3D late gadolinium enhancement in a single prolonged breath-hold using supplemental oxygenation and hyperventilation.

PubMed

Roujol, Sébastien; Basha, Tamer A; Akçakaya, Mehmet; Foppa, Murilo; Chan, Raymond H; Kissinger, Kraig V; Goddu, Beth; Berg, Sophie; Manning, Warren J; Nezafat, Reza

2014-09-01

To evaluate the feasibility of three-dimensional (3D) single breath-hold late gadolinium enhancement (LGE) of the left ventricle (LV) using supplemental oxygen and hyperventilation and compressed-sensing acceleration. Breath-hold metrics [breath-hold duration, diaphragmatic/LV position drift, and maximum variation of R wave to R wave (RR) interval] without and with supplemental oxygen and hyperventilation were assessed in healthy adult subjects using a real-time single shot acquisition. Ten healthy subjects and 13 patients then underwent assessment of the proposed 3D breath-hold LGE acquisition (field of view = 320 × 320 × 100 mm(3) , resolution = 1.6 × 1.6 × 5.0 mm(3) , acceleration rate of 4) and a free-breathing acquisition with right hemidiaphragm navigator (NAV) respiratory gating. Semiquantitative grading of overall image quality, motion artifact, myocardial nulling, and diagnostic value was performed by consensus of two blinded observers. Supplemental oxygenation and hyperventilation increased the breath-hold duration (35 ± 11 s to 58 ± 21 s; P < 0.0125) without significant impact on diaphragmatic/LV position drift or maximum variation of RR interval (both P > 0.01). LGE images were of similar quality when compared with free-breathing acquisitions, but with reduced total scan time (85 ± 22 s to 35 ± 6 s; P < 0.001). Supplemental oxygenation and hyperventilation allow for prolonged breath-holding and enable single breath-hold 3D accelerated LGE with similar image quality as free breathing with NAV. Copyright © 2013 Wiley Periodicals, Inc.

All APAPs Are Not Equivalent for the Treatment of Sleep Disordered Breathing: A Bench Evaluation of Eleven Commercially Available Devices

PubMed Central

Zhu, Kaixian; Roisman, Gabriel; Aouf, Sami; Escourrou, Pierre

2015-01-01

Study Objectives: This study challenged on a bench-test the efficacy of auto-titrating positive airway pressure (APAP) devices for obstructive sleep disordered breathing treatment and evaluated the accuracy of the device reports. Methods: Our bench consisted of an active lung simulator and a Starling resistor. Eleven commercially available APAP devices were evaluated on their reactions to single-type SDB sequences (obstructive apnea and hypopnea, central apnea, and snoring), and to a long general breathing scenario (5.75 h) simulating various SDB during four sleep cycles and to a short scenario (95 min) simulating one sleep cycle. Results: In the single-type sequence of 30-minute repetitive obstructive apneas, only 5 devices normalized the airflow (> 70% of baseline breathing amplitude). Similarly, normalized breathing was recorded with 8 devices only for a 20-min obstructive hypopnea sequence. Five devices increased the pressure in response to snoring. Only 4 devices maintained a constant minimum pressure when subjected to repeated central apneas with an open upper airway. In the long general breathing scenario, the pressure responses and the treatment efficacy differed among devices: only 5 devices obtained a residual obstructive AHI < 5/h. During the short general breathing scenario, only 2 devices reached the same treatment efficacy (p < 0.001), and 3 devices underestimated the AHI by > 10% (p < 0.001). The long scenario led to more consistent device reports. Conclusion: Large differences between APAP devices in the treatment efficacy and the accuracy of report were evidenced in the current study. Citation: Zhu K, Roisman G, Aouf S, Escourrou P. All APAPs are not equivalent for the treatment of sleep disordered breathing: a bench evaluation of eleven commercially available devices. J Clin Sleep Med 2015;11(7):725–734. PMID:25766708

Status of selected ion flow tube MS: accomplishments and challenges in breath analysis and other areas.

PubMed

Smith, David; Španěl, Patrik

2016-06-01

This article reflects our observations of recent accomplishments made using selected ion flow tube MS (SIFT-MS). Only brief descriptions are given of SIFT-MS as an analytical method and of the recent extensions to the underpinning analytical ion chemistry required to realize more robust analyses. The challenge of breath analysis is given special attention because, when achieved, it renders analysis of other air media relatively straightforward. Brief overviews are given of recent SIFT-MS breath analyses by leading research groups, noting the desirability of detection and quantification of single volatile biomarkers rather than reliance on statistical analyses, if breath analysis is to be accepted into clinical practice. A 'strengths, weaknesses, opportunities and threats' analysis of SIFT-MS is made, which should help to increase its utility for trace gas analysis.

Single-breath analysis using a novel simple sampler and capillary electrophoresis with contactless conductometric detection.

PubMed

Greguš, Michal; Foret, František; Kubáň, Petr

2015-02-01

The analysis of ionic content of exhaled breath condensate (EBC) from one single breath by CE with C(4) D is demonstrated for the first time. A miniature sampler made from a 2-mL syringe and an aluminum cooling cylinder for collection of EBC was developed. Various parameters of the sampler that influence its collection efficiency, repeatability, and effect of respiratory patterns were studied in detail. Efficient procedures for the cleanup of the miniature sampler were also developed and resulted in significant improvement of sampling repeatability. Analysis of EBC was performed by CE-C(4) D in a 60 mM MES/l-histidine BGE with 30 μM CTAB and 2 mM 18-crown-6 at pH 6 and excellent repeatability of migration times (RSD < 1.3% (n = 7)) and peak areas (RSD < 7% (n = 7)) of 12 inorganic anions, cations, and organic acids was obtained. It has been shown that the breathing pattern has a significant impact on the concentration of the analytes in the collected EBC. As the ventilatory pattern can be easily controlled during single exhalation, the developed collection system and method provides a highly reproducible and fast way of collecting EBC with applicability in point-of-care diagnostics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Patient training in respiratory-gated radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kini, Vijay R.; Vedam, Subrahmanya S.; Keall, Paul J.

2003-03-31

Respiratory gating is used to counter the effects of organ motion during radiotherapy for chest tumors. The effects of variations in patient breathing patterns during a single treatment and from day to day are unknown. We evaluated the feasibility of using patient training tools and their effect on the breathing cycle regularity and reproducibility during respiratory-gated radiotherapy. To monitor respiratory patterns, we used a component of a commercially available respiratory-gated radiotherapy system (Real Time Position Management (RPM) System, Varian Oncology Systems, Palo Alto, CA 94304). This passive marker video tracking system consists of reflective markers placed on the patient's chestmore » or abdomen, which are detected by a wall-mounted video camera. Software installed on a PC interfaced to this camera detects the marker motion digitally and records it. The marker position as a function of time serves as the motion signal that may be used to trigger imaging or treatment. The training tools used were audio prompting and visual feedback, with free breathing as a control. The audio prompting method used instructions to 'breathe in' or 'breathe out' at periodic intervals deduced from patients' own breathing patterns. In the visual feedback method, patients were shown a real-time trace of their abdominal wall motion due to breathing. Using this, they were asked to maintain a constant amplitude of motion. Motion traces of the abdominal wall were recorded for each patient for various maneuvers. Free breathing showed a variable amplitude and frequency. Audio prompting resulted in a reproducible frequency; however, the variability and the magnitude of amplitude increased. Visual feedback gave a better control over the amplitude but showed minor variations in frequency. We concluded that training improves the reproducibility of amplitude and frequency of patient breathing cycles. This may increase the accuracy of respiratory-gated radiation therapy.« less

Tidal Volume Single Breath Washout of Two Tracer Gases - A Practical and Promising Lung Function Test

PubMed Central

Singer, Florian; Stern, Georgette; Thamrin, Cindy; Fuchs, Oliver; Riedel, Thomas; Gustafsson, Per; Frey, Urs; Latzin, Philipp

2011-01-01

Background Small airway disease frequently occurs in chronic lung diseases and may cause ventilation inhomogeneity (VI), which can be assessed by washout tests of inert tracer gas. Using two tracer gases with unequal molar mass (MM) and diffusivity increases specificity for VI in different lung zones. Currently washout tests are underutilised due to the time and effort required for measurements. The aim of this study was to develop and validate a simple technique for a new tidal single breath washout test (SBW) of sulfur hexafluoride (SF6) and helium (He) using an ultrasonic flowmeter (USFM). Methods The tracer gas mixture contained 5% SF6 and 26.3% He, had similar total MM as air, and was applied for a single tidal breath in 13 healthy adults. The USFM measured MM, which was then plotted against expired volume. USFM and mass spectrometer signals were compared in six subjects performing three SBW. Repeatability and reproducibility of SBW, i.e., area under the MM curve (AUC), were determined in seven subjects performing three SBW 24 hours apart. Results USFM reliably measured MM during all SBW tests (n = 60). MM from USFM reflected SF6 and He washout patterns measured by mass spectrometer. USFM signals were highly associated with mass spectrometer signals, e.g., for MM, linear regression r-squared was 0.98. Intra-subject coefficient of variation of AUC was 6.8%, and coefficient of repeatability was 11.8%. Conclusion The USFM accurately measured relative changes in SF6 and He washout. SBW tests were repeatable and reproducible in healthy adults. We have developed a fast, reliable, and straightforward USFM based SBW method, which provides valid information on SF6 and He washout patterns during tidal breathing. PMID:21423739

Specialized physiological studies in support of manned space flight

NASA Technical Reports Server (NTRS)

Luft, U. C.

1973-01-01

The areas of physiological research reported include: (1) evaluation of the single-breath method for determining cardiac output, (2) optimum protocol for the assessment of cardio-pulmonary competence, (3) body fluids and electrolytes under conditions of single and combined stress, (4) re-evaluation of the open-circuit method for measuring metabolic rate with regard to the alleged metabolic production of gaseous nitrogen, and (5) the use of the forced-oscillation method to determine total respiratory conductance in healthy subjects and pulmonary patients.

Acquiring 4D Thoracic CT Scans Using Ciné CT Acquisition

NASA Astrophysics Data System (ADS)

Low, Daniel

One method for acquiring 4D thoracic CT scans is to use ciné acquisition. Ciné acquisition is conducted by rotating the gantry and acquiring x-ray projections while keeping the couch stationary. After a complete rotation, a single set of CT slices, the number corresponding to the number of CT detector rows, is produced. The rotation period is typically sub second so each image set corresponds to a single point in time. The ciné image acquisition is repeated for at least one breathing cycle to acquire images throughout the breathing cycle. Once the images are acquired at a single couch position, the couch is moved to the abutting position and the acquisition is repeated. Post-processing of the images sets typically resorts the sets into breathing phases, stacking images from a specific phase to produce a thoracic CT scan at that phase. Benefits of the ciné acquisition protocol include, the ability to precisely identify the phase with respect to the acquired image, the ability to resort images after reconstruction, and the ability to acquire images over arbitrarily long times and for arbitrarily many images (within dose constraints).

Online recording of ethane traces in human breath via infrared laser spectroscopy.

PubMed

von Basum, Golo; Dahnke, Hannes; Halmer, Daniel; Hering, Peter; Mürtz, Manfred

2003-12-01

A method is described for rapidly measuring the ethane concentration in exhaled human breath. Ethane is considered a volatile marker for lipid peroxidation. The breath samples are analyzed in real time during single exhalations by means of infrared cavity leak-out spectroscopy. This is an ultrasensitive laser-based method for the analysis of trace gases on the sub-parts per billion level. We demonstrate that this technique is capable of online quantifying of ethane traces in exhaled human breath down to 500 parts per trillion with a time resolution of better than 800 ms. This study includes what we believe to be the first measured expirograms for trace fractions of ethane. The expirograms were recorded after a controlled inhalation exposure to 1 part per million of ethane. The normalized slope of the alveolar plateau was determined, which shows a linear increase over the first breathing cycles and ends in a mean value between 0.21 and 0.39 liter-1. The washout process was observed for a time period of 30 min and was modelled by a threefold exponential decay function, with decay times ranging from 12 to 24, 341 to 481, and 370 to 1770 s. Our analyzer provides a promising noninvasive tool for online monitoring of the oxidative stress status.

Real-time continuous visual biofeedback in the treatment of speech breathing disorders following childhood traumatic brain injury: report of one case.

PubMed

Murdoch, B E; Pitt, G; Theodoros, D G; Ward, E C

1999-01-01

The efficacy of traditional and physiological biofeedback methods for modifying abnormal speech breathing patterns was investigated in a child with persistent dysarthria following severe traumatic brain injury (TBI). An A-B-A-B single-subject experimental research design was utilized to provide the subject with two exclusive periods of therapy for speech breathing, based on traditional therapy techniques and physiological biofeedback methods, respectively. Traditional therapy techniques included establishing optimal posture for speech breathing, explanation of the movement of the respiratory muscles, and a hierarchy of non-speech and speech tasks focusing on establishing an appropriate level of sub-glottal air pressure, and improving the subject's control of inhalation and exhalation. The biofeedback phase of therapy utilized variable inductance plethysmography (or Respitrace) to provide real-time, continuous visual biofeedback of ribcage circumference during breathing. As in traditional therapy, a hierarchy of non-speech and speech tasks were devised to improve the subject's control of his respiratory pattern. Throughout the project, the subject's respiratory support for speech was assessed both instrumentally and perceptually. Instrumental assessment included kinematic and spirometric measures, and perceptual assessment included the Frenchay Dysarthria Assessment, Assessment of Intelligibility of Dysarthric Speech, and analysis of a speech sample. The results of the study demonstrated that real-time continuous visual biofeedback techniques for modifying speech breathing patterns were not only effective, but superior to the traditional therapy techniques for modifying abnormal speech breathing patterns in a child with persistent dysarthria following severe TBI. These results show that physiological biofeedback techniques are potentially useful clinical tools for the remediation of speech breathing impairment in the paediatric dysarthric population.

Nonenhanced MR angiography of the pulmonary arteries using single-shot radial quiescent-interval slice-selective (QISS): a technical feasibility study.

PubMed

Edelman, Robert R; Silvers, Robert I; Thakrar, Kiran H; Metzl, Mark D; Nazari, Jose; Giri, Shivraman; Koktzoglou, Ioannis

2017-06-30

For evaluation of the pulmonary arteries in patients suspected of pulmonary embolism, CT angiography (CTA) is the first-line imaging test with contrast-enhanced MR angiography (CEMRA) a potential alternative. Disadvantages of CTA include exposure to ionizing radiation and an iodinated contrast agent, while CEMRA is sensitive to respiratory motion and requires a gadolinium-based contrast agent. The primary goal of our technical feasibility study was to evaluate pulmonary arterial conspicuity using breath-hold and free-breathing implementations of a recently-developed nonenhanced approach, single-shot radial quiescent-interval slice-selective (QISS) MRA. Breath-hold and free-breathing, navigator-gated versions of radial QISS MRA were evaluated at 1.5 Tesla in three healthy subjects and 11 patients without pulmonary embolism or arterial occlusion by CTA. Images were scored by three readers for conspicuity of the pulmonary arteries through the level of the segmental branches. In addition, one patient with pulmonary embolism was imaged. Scan time for a 54-slice acquisition spanning the pulmonary arteries was less than 2 minutes for breath-hold QISS, and less than 3.4 min using free-breathing QISS. Pulmonary artery branches through the segmental level were conspicuous with either approach. Free-breathing scans showed only mild blurring compared with breath-hold scans. For both readers, less than 1% of pulmonary arterial segments were rated as "not seen" for breath-hold and navigator-gated QISS, respectively. In subjects with atrial fibrillation, single-shot radial QISS consistently depicted the pulmonary artery branches, whereas navigator-gated 3D balanced steady-state free precession showed motion artifacts. In one patient with pulmonary embolism, radial QISS demonstrated central pulmonary emboli comparably to CEMRA and CTA. The thrombi were highly conspicuous on radial QISS images, but appeared subtle and were not prospectively identified on scout images acquired using a single-shot bSSFP acquisition. In this technical feasibility study, both breath-hold and free-breathing single-shot radial QISS MRA enabled rapid, consistent demonstration of the pulmonary arteries through the level of the segmental branches, with only minimal artifacts from respiratory motion and cardiac arrhythmias. Based on these promising initial results, further evaluation in patients with suspected pulmonary embolism appears warranted.

A new method for measuring lung deposition efficiency of airborne nanoparticles in a single breath

NASA Astrophysics Data System (ADS)

Jakobsson, Jonas K. F.; Hedlund, Johan; Kumlin, John; Wollmer, Per; Löndahl, Jakob

2016-11-01

Assessment of respiratory tract deposition of nanoparticles is a key link to understanding their health impacts. An instrument was developed to measure respiratory tract deposition of nanoparticles in a single breath. Monodisperse nanoparticles are generated, inhaled and sampled from a determined volumetric lung depth after a controlled residence time in the lung. The instrument was characterized for sensitivity to inter-subject variability, particle size (22, 50, 75 and 100 nm) and breath-holding time (3-20 s) in a group of seven healthy subjects. The measured particle recovery had an inter-subject variability 26-50 times larger than the measurement uncertainty and the results for various particle sizes and breath-holding times were in accordance with the theory for Brownian diffusion and values calculated from the Multiple-Path Particle Dosimetry model. The recovery was found to be determined by residence time and particle size, while respiratory flow-rate had minor importance in the studied range 1-10 L/s. The instrument will be used to investigate deposition of nanoparticles in patients with respiratory disease. The fast and precise measurement allows for both diagnostic applications, where the disease may be identified based on particle recovery, and for studies with controlled delivery of aerosol-based nanomedicine to specific regions of the lungs.

Single Breath-Hold Non-Contrast Thoracic MRA Using Highly-Accelerated Parallel Imaging With a 32-element Coil Array

PubMed Central

Xu, Jian; Mcgorty, Kelly Anne; Lim, Ruth. P.; Bruno, Mary; Babb, James S.; Srichai, Monvadi B.; Kim, Daniel; Sodickson, Daniel K.

2011-01-01

OBJECTIVE To evaluate the feasibility of performing single breath-hold 3D thoracic non-contrast magnetic resonance angiography (NC-MRA) using highly-accelerated parallel imaging. MATERIALS AND METHODS We developed a single breath-hold NC MRA pulse sequence using balanced steady state free precession (SSFP) readout and highly-accelerated parallel imaging. In 17 subjects, highly-accelerated non-contrast MRA was compared against electrocardiogram (ECG)-triggered contrast-enhanced MRA. Anonymized images were randomized for blinded review by two independent readers for image quality, artifact severity in 8 defined vessel segments and aortic dimensions in 6 standard sites. NC-MRA and CE-MRA were compared in terms of these measures using paired sample t and Wilcoxon tests. RESULTS The overall image quality (3.21±0.68 for NC-MRA vs. 3.12±0.71 for CE-MRA) and artifact (2.87±1.01 for NC-MRA vs. 2.92±0.87 for CE-MRA) scores were not significantly different, but there were significant differences for the great vessel and coronary artery origins. NC-MRA demonstrated significantly lower aortic diameter measurements compared to CE-MRA; however, this difference was not considered clinically relevant (>3 mm difference) for less than 12% of segments, most commonly at the sinotubular junction. Mean total scan time was significantly lower for NC-MRA compared to CE-MRA (18.2 ± 6.0s vs. 28.1 ± 5.4s, respectively; p < 0.05). CONCLUSION Single breath-hold NC-MRA is feasible and can be a useful alternative for evaluation and follow-up of thoracic aortic diseases. PMID:22147589

Clinical photoacoustic computed tomography of the human breast in vivo within a single breath hold

NASA Astrophysics Data System (ADS)

Lin, Li; Hu, Peng; Shi, Junhui; Appleton, Catherine M.; Maslov, Konstantin; Wang, Lihong V.

2018-03-01

We have developed a single-breath-hold photoacoustic computed tomography (SBH-PACT) system to detect tumors and reveal detailed angiographic information about human breasts. SBH-PACT provides high spatial and temporal resolutions with a deep in vivo penetration depth of over 4 cm. A volumetric breast image can be acquired by scanning the breast within a single breath hold ( 15 sec). We imaged a healthy female volunteer and seven breast cancer patients. SBH-PACT clearly identified all tumors by revealing higher blood vessel densities and lower compliance associated with the tumors

Chiral pathways in DNA dinucleotides using gradient optimized refinement along metastable borders

NASA Astrophysics Data System (ADS)

Romano, Pablo; Guenza, Marina

We present a study of DNA breathing fluctuations using Markov state models (MSM) with our novel refinement procedure. MSM have become a favored method of building kinetic models, however their accuracy has always depended on using a significant number of microstates, making the method costly. We present a method which optimizes macrostates by refining borders with respect to the gradient along the free energy surface. As the separation between macrostates contains highest discretization errors, this method corrects for any errors produced by limited microstate sampling. Using our refined MSM methods, we investigate DNA breathing fluctuations, thermally induced conformational changes in native B-form DNA. Running several microsecond MD simulations of DNA dinucleotides of varying sequences, to include sequence and polarity effects, we've analyzed using our refined MSM to investigate conformational pathways inherent in the unstacking of DNA bases. Our kinetic analysis has shown preferential chirality in unstacking pathways that may be critical in how proteins interact with single stranded regions of DNA. These breathing dynamics can help elucidate the connection between conformational changes and key mechanisms within protein-DNA recognition. NSF Chemistry Division (Theoretical Chemistry), the Division of Physics (Condensed Matter: Material Theory), XSEDE.

Short-Term Intra-Subject Variation in Exhaled Volatile Organic Compounds (VOCs) in COPD Patients and Healthy Controls and Its Effect on Disease Classification

PubMed Central

Phillips, Christopher; Mac Parthaláin, Neil; Syed, Yasir; Deganello, Davide; Claypole, Timothy; Lewis, Keir

2014-01-01

Exhaled volatile organic compounds (VOCs) are of interest for their potential to diagnose disease non-invasively. However, most breath VOC studies have analyzed single breath samples from an individual and assumed them to be wholly consistent representative of the person. This provided the motivation for an investigation of the variability of breath profiles when three breath samples are taken over a short time period (two minute intervals between samples) for 118 stable patients with Chronic Obstructive Pulmonary Disease (COPD) and 63 healthy controls and analyzed by gas chromatography and mass spectroscopy (GC/MS). The extent of the variation in VOC levels differed between COPD and healthy subjects and the patterns of variation differed for isoprene versus the bulk of other VOCs. In addition, machine learning approaches were applied to the breath data to establish whether these samples differed in their ability to discriminate COPD from healthy states and whether aggregation of multiple samples, into single data sets, could offer improved discrimination. The three breath samples gave similar classification accuracy to one another when evaluated separately (66.5% to 68.3% subjects classified correctly depending on the breath repetition used). Combining multiple breath samples into single data sets gave better discrimination (73.4% subjects classified correctly). Although accuracy is not sufficient for COPD diagnosis in a clinical setting, enhanced sampling and analysis may improve accuracy further. Variability in samples, and short-term effects of practice or exertion, need to be considered in any breath testing program to improve reliability and optimize discrimination. PMID:24957028

Short-Term Intra-Subject Variation in Exhaled Volatile Organic Compounds (VOCs) in COPD Patients and Healthy Controls and Its Effect on Disease Classification.

PubMed

Phillips, Christopher; Mac Parthaláin, Neil; Syed, Yasir; Deganello, Davide; Claypole, Timothy; Lewis, Keir

2014-05-09

Exhaled volatile organic compounds (VOCs) are of interest for their potential to diagnose disease non-invasively. However, most breath VOC studies have analyzed single breath samples from an individual and assumed them to be wholly consistent representative of the person. This provided the motivation for an investigation of the variability of breath profiles when three breath samples are taken over a short time period (two minute intervals between samples) for 118 stable patients with Chronic Obstructive Pulmonary Disease (COPD) and 63 healthy controls and analyzed by gas chromatography and mass spectroscopy (GC/MS). The extent of the variation in VOC levels differed between COPD and healthy subjects and the patterns of variation differed for isoprene versus the bulk of other VOCs. In addition, machine learning approaches were applied to the breath data to establish whether these samples differed in their ability to discriminate COPD from healthy states and whether aggregation of multiple samples, into single data sets, could offer improved discrimination. The three breath samples gave similar classification accuracy to one another when evaluated separately (66.5% to 68.3% subjects classified correctly depending on the breath repetition used). Combining multiple breath samples into single data sets gave better discrimination (73.4% subjects classified correctly). Although accuracy is not sufficient for COPD diagnosis in a clinical setting, enhanced sampling and analysis may improve accuracy further. Variability in samples, and short-term effects of practice or exertion, need to be considered in any breath testing program to improve reliability and optimize discrimination.

The impact of dual-source parallel radiofrequency transmission with patient-adaptive shimming on the cardiac magnetic resonance in children at 3.0 T.

PubMed

Wang, Haipeng; Qiu, Liyun; Wang, Guangbin; Gao, Fei; Jia, Haipeng; Zhao, Junyu; Chen, Weibo; Wang, Cuiyan; Zhao, Bin

2017-06-01

The cardiac magnetic resonance (CMR) of children at 3.0 T presents a unique set of technical challenges because of their small cardiac anatomical structures, fast heart rates, and the limited ability to keep motionless and hold breathe, which could cause problems associated with field inhomogeneity and degrade the image quality. The aim of our study was to evaluate the effect of dual-source parallel radiofrequency (RF) transmission on the B1 homogeneity and image quality in children with CMR at 3.0 T. The study was approved by the institutional ethics committee and written informed consent was obtained. A total of 30 free-breathing children and 30 breath-hold children performed CMR examinations with dual-source and single-source RF transmission. The B1 homogeneity, contrast ratio (CR) of cine images, and off-resonance artifacts in cine images between dual-source and single-source RF transmission were assessed in free-breathing and breath-hold groups, respectively. In both free-breathing and breath-hold groups, higher mean percentage of flip angle (free-breathing group: 104.2 ± 4.6 vs 95.5 ± 6.3, P < .001; breath-hold group: 101.5 ± 5.1 vs 92.5 ± 6.3, P < .001) and lower coefficient of variation (free-breathing group: 0.06 ± 0.02 vs 0.09 ± 0.03, P < .001; breath-hold group: 0.07 ± 0.03 vs 0.10 ± 0.04, P = .005) were found with dual-source than with single-source RF transmission. Both the CRs in the horizontal long axis (HLA) and short axis of cine images with dual-source RF transmission was improved (P < .05 for all). The scores of off-resonance artifacts in the HLA with dual-source RF transmission were higher in both free-breathing and breath-hold groups (P < .05 for all), with substantial interreader agreement (kappa values from 0.68 to 0.74). Compared with conventional single-source, dual-source parallel RF transmission could significantly improve the B1 homogeneity and image quality for CMR in children at 3.0 T. This technology could be taken into account in CMR for children with cardiac diseases.

Multibreath alveolar oxygen tension imaging.

PubMed

Clapp, Justin; Hamedani, Hooman; Kadlecek, Stephen; Xin, Yi; Shaghaghi, Hoora; Siddiqui, Sarmad; Rossman, Milton D; Rizi, Rahim R

2016-10-01

This study tested the ability of a multibreath hyperpolarized HP (3) He MRI protocol to increase the accuracy of regional alveolar oxygen tension (PA O2 ) measurements by lessening the influence of gas-flow artifacts. Conventional single-breath PA O2 measurement has been susceptible to error induced by intervoxel gas flow, particularly when used to study subjects with moderate-to-severe chronic obstructive pulmonary disease (COPD). Both single-breath and multibreath PA O2 imaging schemes were implemented in seven human subjects (one healthy, three asymptomatic smokers, and three COPD). The number and location of voxels with nonphysiologic PA O2 values generated by intervoxel gas flow were compared between the two protocols. The multibreath scheme resulted in a significantly lower total percentage of nonphysiologic PA O2 values (6.0%) than the single-breath scheme (13.7%) (P = 0.006). PA O2 maps showed several patterns of gas-flow artifacts that were present in the single-breath protocol but mitigated by the multibreath approach. Multibreath imaging also allowed for the analysis of slow-filling areas that presented no signal after a single breath. A multibreath approach enhances the accuracy and completeness of noninvasive PA O2 measurement by significantly lessening the proportion of nonphysiologic values generated by intervoxel gas flow. Magn Reson Med 76:1092-1101, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Matter Over Mind: A Randomised-Controlled Trial of Single-Session Biofeedback Training on Performance Anxiety and Heart Rate Variability in Musicians

PubMed Central

Wells, Ruth; Outhred, Tim; Heathers, James A. J.; Quintana, Daniel S.; Kemp, Andrew H.

2012-01-01

Background Musical performance is a skilled activity performed under intense pressure, thus is often a profound source of anxiety. In other contexts, anxiety and its concomitant symptoms of sympathetic nervous system arousal have been successfully ameliorated with HRV biofeedback (HRV BF), a technique involving slow breathing which augments autonomic and emotional regulatory capacity. Objective: This randomised-controlled study explored the impact of a single 30-minute session of HRV BF on anxiety in response to a highly stressful music performance. Methods A total of 46 trained musicians participated in this study and were randomly allocated to a slow breathing with or without biofeedback or no-treatment control group. A 3 Group×2 Time mixed experimental design was employed to compare the effect of group before and after intervention on performance anxiety (STAI-S) and frequency domain measures of HRV. Results Slow breathing groups (n = 30) showed significantly greater improvements in high frequency (HF) and LF/HF ratio measures of HRV relative to control (n = 15) during 5 minute recordings of performance anticipation following the intervention (effect size: η2 = 0.122 and η2 = 0.116, respectively). The addition of biofeedback to a slow breathing protocol did not produce differential results. While intervention groups did not exhibit an overall reduction in self-reported anxiety, participants with high baseline anxiety who received the intervention (n = 15) displayed greater reductions in self-reported state anxiety relative to those in the control condition (n = 7) (r = 0.379). Conclusions These findings indicate that a single session of slow breathing, regardless of biofeedback, is sufficient for controlling physiological arousal in anticipation of psychosocial stress associated with music performance and that slow breathing is particularly helpful for musicians with high levels of anxiety. Future research is needed to further examine the effects of HRV BF as a low-cost, non-pharmacological treatment for music performance anxiety. PMID:23056361

A new method for measuring lung deposition efficiency of airborne nanoparticles in a single breath

PubMed Central

Jakobsson, Jonas K. F.; Hedlund, Johan; Kumlin, John; Wollmer, Per; Löndahl, Jakob

2016-01-01

Assessment of respiratory tract deposition of nanoparticles is a key link to understanding their health impacts. An instrument was developed to measure respiratory tract deposition of nanoparticles in a single breath. Monodisperse nanoparticles are generated, inhaled and sampled from a determined volumetric lung depth after a controlled residence time in the lung. The instrument was characterized for sensitivity to inter-subject variability, particle size (22, 50, 75 and 100 nm) and breath-holding time (3–20 s) in a group of seven healthy subjects. The measured particle recovery had an inter-subject variability 26–50 times larger than the measurement uncertainty and the results for various particle sizes and breath-holding times were in accordance with the theory for Brownian diffusion and values calculated from the Multiple-Path Particle Dosimetry model. The recovery was found to be determined by residence time and particle size, while respiratory flow-rate had minor importance in the studied range 1–10 L/s. The instrument will be used to investigate deposition of nanoparticles in patients with respiratory disease. The fast and precise measurement allows for both diagnostic applications, where the disease may be identified based on particle recovery, and for studies with controlled delivery of aerosol-based nanomedicine to specific regions of the lungs. PMID:27819335

Single-Breath-Hold Whole-heart Unenhanced Coronary MRA Using Multi-shot Gradient Echo EPI at 3T: Comparison with Free-breathing Turbo-field-echo Coronary MRA on Healthy Volunteers.

PubMed

Iyama, Yuji; Nakaura, Takeshi; Nagayama, Yasunori; Oda, Seitaro; Utsunomiya, Daisuke; Kidoh, Masafumi; Yuki, Hideaki; Hirata, Kenichiro; Namimoto, Tomohiro; Kitajima, Mika; Morita, Kosuke; Funama, Yoshinori; Takemura, Atsushi; Okuaki, Tomoyuki; Yamashita, Yasuyuki

2018-04-10

We investigated the feasibility of single breath hold unenhanced coronary MRA using multi-shot gradient echo planar imaging (MSG-EPI) on a 3T-scanner. Fourteen volunteers underwent single breath hold coronary MRA with a MSG-EPI and free-breathing turbo field echo (TFE) coronary MRA at 3T. The acquisition time, signal to noise ratio (SNR), and the contrast of the sequences were compared with the paired t-test. Readers evaluated the image contrast, noise, sharpness, artifacts, and the overall image quality. The acquisition time was 88.1% shorter for MSG-EPI than TFE (24.7 ± 2.5 vs 206.4 ± 23.1 sec, P < 0.01). The SNR was significantly higher on MSG-EPI than TFE scans (P < 0.01). There was no significant difference in the contrast on MSG-EPI and TFE scans (1.8 ± 0.3 vs 1.9 ± 0.3, P = 0.24). There was no significant difference in image contrast, image sharpness, and overall image quality between two scan techniques. The score of image noise and artifact were significantly higher on MSG-EPI than TFE scans (P < 0.05). The single breath hold MSG-EPI sequence is a promising technique for shortening the scan time and for preserving the image quality of unenhanced whole heart coronary MRA on a 3T scanner.

A Portable Real-Time Ringdown Breath Acetone Analyzer: Toward Potential Diabetic Screening and Management.

PubMed

Jiang, Chenyu; Sun, Meixiu; Wang, Zhennan; Chen, Zhuying; Zhao, Xiaomeng; Yuan, Yuan; Li, Yingxin; Wang, Chuji

2016-07-30

Breath analysis has been considered a suitable tool to evaluate diseases of the respiratory system and those that involve metabolic changes, such as diabetes. Breath acetone has long been known as a biomarker for diabetes. However, the results from published data by far have been inconclusive regarding whether breath acetone is a reliable index of diabetic screening. Large variations exist among the results of different studies because there has been no "best-practice method" for breath-acetone measurements as a result of technical problems of sampling and analysis. In this mini-review, we update the current status of our development of a laser-based breath acetone analyzer toward real-time, one-line diabetic screening and a point-of-care instrument for diabetic management. An integrated standalone breath acetone analyzer based on the cavity ringdown spectroscopy technique has been developed. The instrument was validated by using the certificated gas chromatography-mass spectrometry. The linear fittings suggest that the obtained acetone concentrations via both methods are consistent. Breath samples from each individual subject under various conditions in total, 1257 breath samples were taken from 22 Type 1 diabetic (T1D) patients, 312 Type 2 diabetic (T2D) patients, which is one of the largest numbers of T2D subjects ever used in a single study, and 52 non-diabetic healthy subjects. Simultaneous blood glucose (BG) levels were also tested using a standard diabetic management BG meter. The mean breath acetone concentrations were determined to be 4.9 ± 16 ppm (22 T1D), and 1.5 ± 1.3 ppm (312 T2D), which are about 4.5 and 1.4 times of the one in the 42 non-diabetic healthy subjects, 1.1 ± 0.5 ppm, respectively. A preliminary quantitative correlation (R = 0.56, p < 0.05) between the mean individual breath acetone concentration and the mean individual BG levels does exist in 20 T1D subjects with no ketoacidosis. No direct correlation is observed in T1D subjects, T2D subjects, and healthy subjects. The results from a relatively large number of subjects tested indicate that an elevated mean breath acetone concentration exists in diabetic patients in general. Although many physiological parameters affect breath acetone, under a specifically controlled condition fast (<1 min) and portable breath acetone measurement can be used for screening abnormal metabolic status including diabetes, for point-of-care monitoring status of ketone bodies which have the signature smell of breath acetone, and for breath acetone related clinical studies requiring a large number of tests.

COLLECTION OF A SINGLE ALVEOLAR EXHALED BREATH FOR VOLATILE ORGANIC COMPOUNDS ANALYSIS

EPA Science Inventory

Measurement of specific organic compounds in exhaled breath has been used as an indicator of recent exposure to pollutants or as an indicator of the health of an individual. Typical application involves the collection of multiple breaths onto a sorbent cartridge or into an evacua...

Photoplethysmography as a single source for analysis of sleep-disordered breathing in patients with severe cardiovascular disease.

PubMed

Amir, Offer; Barak-Shinar, Deganit; Henry, Antonietta; Smart, Frank W

2012-02-01

Sleep-disordered breathing and Cheyne-Stokes breathing are often not diagnosed, especially in cardiovascular patients. An automated system based on photoplethysmographic signals might provide a convenient screening and diagnostic solution for patient evaluation at home or in an ambulatory setting. We compared event detection and classification obtained by full polysomnography (the 'gold standard') and by an automated new algorithm system in 74 subjects. Each subject underwent overnight polysomnography, 60 in a hospital cardiology department and 14 while being tested for suspected sleep-disordered breathing in a sleep laboratory. The sleep-disordered breathing and Cheyne-Stokes breathing parameters measured by a new automated algorithm system correlated very well with the corresponding results obtained by full polysomnography. The sensitivity of the Cheyne-Stokes breathing detected from the system compared to full polysomnography was 92% [95% confidence interval (CI): 78.6-98.3%] and specificity 94% (95% CI: 81.3-99.3%). Comparison of the Apnea Hyponea Index with a cutoff level of 15 shows a sensitivity of 98% (95% CI: 87.1-99.6%) and specificity of 96% (95% CI: 79.8-99.3%). The detection of respiratory events showed agreement of approximately 80%. Regression and Bland-Altman plots revealed good agreement between the two methods. Relative to gold-standard polysomnography, the simply used automated system in this study yielded an acceptable analysis of sleep- and/or cardiac-related breathing disorders. Accordingly, and given the convenience and simplicity of its application, this system can be considered as a suitable platform for home and ambulatory screening and diagnosis of sleep-disordered breathing in patients with cardiovascular disease. © 2011 European Sleep Research Society.

Effects of Diaphragmatic Breathing Patterns on Balance: A Preliminary Clinical Trial.

PubMed

Stephens, Rylee J; Haas, Mitchell; Moore, William L; Emmil, Jordan R; Sipress, Jayson A; Williams, Alex

The purpose of this study was to determine the feasibility of performing a larger study to determine if training in diaphragmatic breathing influences static and dynamic balance. A group of 13 healthy persons (8 men, 5 women), who were staff, faculty, or students at the University of Western States participated in an 8-week breathing and balance study using an uncontrolled clinical trial design. Participants were given a series of breathing exercises to perform weekly in the clinic and at home. Balance and breathing were assessed at the weekly clinic sessions. Breathing was evaluated with Liebenson's breathing assessment, static balance with the Modified Balance Error Scoring System, and dynamic balance with OptoGait's March in Place protocol. Improvement was noted in mean diaphragmatic breathing scores (1.3 to 2.6, P < .001), number of single-leg stance balance errors (7.1 to 3.8, P = .001), and tandem stance balance errors (3.2 to 0.9, P = .039). A decreasing error rate in single-leg stance was associated with improvement in breathing score within participants over the 8 weeks of the study (-1.4 errors/unit breathing score change, P < .001). Tandem stance performance did not reach statistical significance (-0.5 error/unit change, P = .118). Dynamic balance was insensitive to balance change, being error free for all participants throughout the study. This proof-of-concept study indicated that promotion of a costal-diaphragmatic breathing pattern may be associated with improvement in balance and suggests that a study of this phenomenon using an experimental design is feasible. Copyright © 2017. Published by Elsevier Inc.

Tidal volume single breath washout of two tracer gases--a practical and promising lung function test.

PubMed

Singer, Florian; Stern, Georgette; Thamrin, Cindy; Fuchs, Oliver; Riedel, Thomas; Gustafsson, Per; Frey, Urs; Latzin, Philipp

2011-03-10

Small airway disease frequently occurs in chronic lung diseases and may cause ventilation inhomogeneity (VI), which can be assessed by washout tests of inert tracer gas. Using two tracer gases with unequal molar mass (MM) and diffusivity increases specificity for VI in different lung zones. Currently washout tests are underutilised due to the time and effort required for measurements. The aim of this study was to develop and validate a simple technique for a new tidal single breath washout test (SBW) of sulfur hexafluoride (SF(6)) and helium (He) using an ultrasonic flowmeter (USFM). The tracer gas mixture contained 5% SF(6) and 26.3% He, had similar total MM as air, and was applied for a single tidal breath in 13 healthy adults. The USFM measured MM, which was then plotted against expired volume. USFM and mass spectrometer signals were compared in six subjects performing three SBW. Repeatability and reproducibility of SBW, i.e., area under the MM curve (AUC), were determined in seven subjects performing three SBW 24 hours apart. USFM reliably measured MM during all SBW tests (n = 60). MM from USFM reflected SF(6) and He washout patterns measured by mass spectrometer. USFM signals were highly associated with mass spectrometer signals, e.g., for MM, linear regression r-squared was 0.98. Intra-subject coefficient of variation of AUC was 6.8%, and coefficient of repeatability was 11.8%. The USFM accurately measured relative changes in SF(6) and He washout. SBW tests were repeatable and reproducible in healthy adults. We have developed a fast, reliable, and straightforward USFM based SBW method, which provides valid information on SF(6) and He washout patterns during tidal breathing.

Whole-heart magnetic resonance coronary angiography with multiple breath-holds and automatic breathing-level tracking

NASA Astrophysics Data System (ADS)

Kuhara, Shigehide; Ninomiya, Ayako; Okada, Tomohisa; Kanao, Shotaro; Kamae, Toshikazu; Togashi, Kaori

2010-05-01

Whole-heart (WH) magnetic resonance coronary angiography (MRCA) studies are usually performed during free breathing while monitoring the position of the diaphragm with real-time motion correction. However, this results in a long scan time and the patient's breathing pattern may change, causing the study to be aborted. Alternatively, WH MRCA can be performed with multiple breath-holds (mBH). However, one problem in the mBH method is that patients cannot hold their breath at the same position every time, leading to image degradation. We have developed a new WH MRCA imaging method that employs both the mBH method and automatic breathing-level tracking to permit automatic tracking of the changes in breathing or breath-hold levels. Evaluation of its effects on WH MRCA image quality showed that this method can provide high-quality images within a shorter scan time. This proposed method is expected to be very useful in clinical WH MRCA studies.

Exploratory breath analyses for assessing toxic dermal exposures of firefighters during suppression of structural burns.

PubMed

Pleil, Joachim D; Stiegel, Matthew A; Fent, Kenneth W

2014-09-01

Firefighters wear fireproof clothing and self-contained breathing apparatus (SCBA) during rescue and fire suppression activities to protect against acute effects from heat and toxic chemicals. Fire services are also concerned about long-term health outcomes from chemical exposures over a working lifetime, in particular about low-level exposures that might serve as initiating events for adverse outcome pathways (AOP) leading to cancer. As part of a larger US National Institute for Occupational Safety and Health (NIOSH) study of dermal exposure protection from safety gear used by the City of Chicago firefighters, we collected pre- and post-fire fighting breath samples and analyzed for single-ring and polycyclic aromatic hydrocarbons as bioindicators of occupational exposure to gas-phase toxicants. Under the assumption that SCBA protects completely against inhalation exposures, any changes in the exhaled profile of combustion products were attributed to dermal exposures from gas and particle penetration through the protective clothing. Two separate rounds of firefighting activity were performed each with 15 firefighters per round. Exhaled breath samples were collected onto adsorbent tubes and analyzed with gas-chromatography-mass spectrometry (GC-MS) with a targeted approach using selective ion monitoring. We found that single ring aromatics and some PAHs were statistically elevated in post-firefighting samples of some individuals, suggesting that fire protective gear may allow for dermal exposures to airborne contaminants. However, in comparison to a previous occupational study of Air Force maintenance personnel where similar compounds were measured, these exposures are much lower suggesting that firefighters' gear is very effective. This study suggests that exhaled breath sampling and analysis for specific targeted compounds is a suitable method for assessing systemic dermal exposure in a simple and non-invasive manner.

Single-breath-hold abdominal [Formula: see text]  mapping using 3D Cartesian Look-Locker with spatiotemporal sparsity constraints.

PubMed

Lugauer, Felix; Wetzl, Jens; Forman, Christoph; Schneider, Manuel; Kiefer, Berthold; Hornegger, Joachim; Nickel, Dominik; Maier, Andreas

2018-06-01

Our aim was to develop and validate a 3D Cartesian Look-Locker [Formula: see text] mapping technique that achieves high accuracy and whole-liver coverage within a single breath-hold. The proposed method combines sparse Cartesian sampling based on a spatiotemporally incoherent Poisson pattern and k-space segmentation, dedicated for high-temporal-resolution imaging. This combination allows capturing tissue with short relaxation times with volumetric coverage. A joint reconstruction of the 3D + inversion time (TI) data via compressed sensing exploits the spatiotemporal sparsity and ensures consistent quality for the subsequent multistep [Formula: see text] mapping. Data from the National Institute of Standards and Technology (NIST) phantom and 11 volunteers, along with reference 2D Look-Locker acquisitions, are used for validation. 2D and 3D methods are compared based on [Formula: see text] values in different abdominal tissues at 1.5 and 3 T. [Formula: see text] maps obtained from the proposed 3D method compare favorably with those from the 2D reference and additionally allow for reformatting or volumetric analysis. Excellent agreement is shown in phantom [bias[Formula: see text] < 2%, bias[Formula: see text] < 5% for (120; 2000) ms] and volunteer data (3D and 2D deviation < 4% for liver, muscle, and spleen) for clinically acceptable scan (20 s) and reconstruction times (< 4 min). Whole-liver [Formula: see text] mapping with high accuracy and precision is feasible in one breath-hold using spatiotemporally incoherent, sparse 3D Cartesian sampling.

From Chicken Breath to the Killers Lake of Cameroon: Uniting Seven Interesting Phenomena with a Single Chemical Underpinning

NASA Astrophysics Data System (ADS)

Delorenzo, Ron

2001-02-01

By using a single equation prototype, seven interesting mysteries and phenomena can be seen as sharing a common chemical underpinning. The applications discussed are the Killer Lakes of Cameroon, chicken breath, the Permian Ocean, the snow line, boiler scale, the Fizz Keeper, and stalactites and stalagmites.

Syllable-related breathing in infants in the second year of life.

PubMed

Parham, Douglas F; Buder, Eugene H; Oller, D Kimbrough; Boliek, Carol A

2011-08-01

This study explored whether breathing behaviors of infants within the 2nd year of life differ between tidal breathing and breathing supporting single unarticulated syllables and canonical/articulated syllables. Vocalizations and breathing kinematics of 9 infants between 53 and 90 weeks of age were recorded. A strict selection protocol was used to identify analyzable breath cycles. Syllables were categorized on the basis of consensus coding. Inspiratory and expiratory durations, excursions, and slopes were calculated for the 3 breath cycle types and were normalized using mean tidal breath measures. Tidal breathing cycles were significantly different from syllable-related cycles on all breathing measures. There were no significant differences between unarticulated syllable cycles and canonical syllable cycles, even after controlling for utterance duration and sound pressure level. Infants in the 2nd year of life exhibit clear differences between tidal breathing and speech-related breathing, but categorically distinct breath support for syllable types with varying articulatory demands was not evident in the present findings. Speech development introduces increasingly complex utterances, so older infants may produce detectable articulation-related adaptations of breathing kinematics. For younger infants, breath support may vary systematically among utterance types, due more to phonatory variations than to articulatory demands.

Free-breathing Sparse Sampling Cine MR Imaging with Iterative Reconstruction for the Assessment of Left Ventricular Function and Mass at 3.0 T.

PubMed

Sudarski, Sonja; Henzler, Thomas; Haubenreisser, Holger; Dösch, Christina; Zenge, Michael O; Schmidt, Michaela; Nadar, Mariappan S; Borggrefe, Martin; Schoenberg, Stefan O; Papavassiliu, Theano

2017-01-01

Purpose To prospectively evaluate the accuracy of left ventricle (LV) analysis with a two-dimensional real-time cine true fast imaging with steady-state precession (trueFISP) magnetic resonance (MR) imaging sequence featuring sparse data sampling with iterative reconstruction (SSIR) performed with and without breath-hold (BH) commands at 3.0 T. Materials and Methods Ten control subjects (mean age, 35 years; range, 25-56 years) and 60 patients scheduled to undergo a routine cardiac examination that included LV analysis (mean age, 58 years; range, 20-86 years) underwent a fully sampled segmented multiple BH cine sequence (standard of reference) and a prototype undersampled SSIR sequence performed during a single BH and during free breathing (non-BH imaging). Quantitative analysis of LV function and mass was performed. Linear regression, Bland-Altman analysis, and paired t testing were performed. Results Similar to the results in control subjects, analysis of the 60 patients showed excellent correlation with the standard of reference for single-BH SSIR (r = 0.93-0.99) and non-BH SSIR (r = 0.92-0.98) for LV ejection fraction (EF), volume, and mass (P < .0001 for all). Irrespective of breath holding, LV end-diastolic mass was overestimated with SSIR (standard of reference: 163.9 g ± 58.9, single-BH SSIR: 178.5 g ± 62.0 [P < .0001], non-BH SSIR: 175.3 g ± 63.7 [P < .0001]); the other parameters were not significantly different (EF: 49.3% ± 11.9 with standard of reference, 48.8% ± 11.8 with single-BH SSIR, 48.8% ± 11 with non-BH SSIR; P = .03 and P = .12, respectively). Bland-Altman analysis showed similar measurement errors for single-BH SSIR and non-BH SSIR when compared with standard of reference measurements for EF, volume, and mass. Conclusion Assessment of LV function with SSIR at 3.0 T is noninferior to the standard of reference irrespective of BH commands. LV mass, however, is overestimated with SSIR. © RSNA, 2016 Online supplemental material is available for this article.

Validation of a new mixing chamber system for breath-by-breath indirect calorimetry.

PubMed

Kim, Do-Yeon; Robergs, Robert Andrew

2012-02-01

Limited validation research exists for applications of breath-by-breath systems of expired gas analysis indirect calorimetry (EGAIC) during exercise. We developed improved hardware and software for breath-by-breath indirect calorimetry (NEW) and validated this system as well as a commercial system (COM) against 2 methods: (i) mechanical ventilation with known calibration gas, and (ii) human subjects testing for 5 min each at rest and cycle ergometer exercise at 100 and 175 W. Mechanical calibration consisted of medical grade and certified calibration gas ((4.95% CO(2), 12.01% O(2), balance N(2)), room air (20.95% O(2), 0.03% CO(2), balance N(2)), and 100% nitrogen), and an air flow turbine calibrated with a 3-L calibration syringe. Ventilation was mimicked manually using complete 3-L calibration syringe manouvers at a rate of 10·min(-1) from a Douglas bag reservoir of calibration gas. The testing of human subjects was completed in a counterbalanced sequence based on 5 repeated tests of all conditions for a single subject. Rest periods of 5 and 10 min followed the 100 and 175 W conditions, respectively. COM and NEW had similar accuracy when tested with known ventilation and gas fractions. However, during human subjects testing COM significantly under-measured carbon dioxide gas fractions, over-measured oxygen gas fractions and minute ventilation, and resulted in errors to each of oxygen uptake, carbon dioxide output, and respiratory exchange ratio. These discrepant findings reveal that controlled ventilation and gas fractions are insufficient to validate breath-by-breath, and perhaps even time-averaged, systems of EGAIC. The errors of the COM system reveal the need for concern over the validity of commercial systems of EGAIC.

Collection of Aerosolized Human Cytokines Using Teflon® Filters

PubMed Central

McKenzie, Jennifer H.; McDevitt, James J.; Fabian, M. Patricia; Hwang, Grace M.; Milton, Donald K.

2012-01-01

Background Collection of exhaled breath samples for the analysis of inflammatory biomarkers is an important area of research aimed at improving our ability to diagnose, treat and understand the mechanisms of chronic pulmonary disease. Current collection methods based on condensation of water vapor from exhaled breath yield biomarker levels at or near the detection limits of immunoassays contributing to problems with reproducibility and validity of biomarker measurements. In this study, we compare the collection efficiency of two aerosol-to-liquid sampling devices to a filter-based collection method for recovery of dilute laboratory generated aerosols of human cytokines so as to identify potential alternatives to exhaled breath condensate collection. Methodology/Principal Findings Two aerosol-to-liquid sampling devices, the SKC® Biosampler and Omni 3000™, as well as Teflon® filters were used to collect aerosols of human cytokines generated using a HEART nebulizer and single-pass aerosol chamber setup in order to compare the collection efficiencies of these sampling methods. Additionally, methods for the use of Teflon® filters to collect and measure cytokines recovered from aerosols were developed and evaluated through use of a high-sensitivity multiplex immunoassay. Our results show successful collection of cytokines from pg/m3 aerosol concentrations using Teflon® filters and measurement of cytokine levels in the sub-picogram/mL concentration range using a multiplex immunoassay with sampling times less than 30 minutes. Significant degradation of cytokines was observed due to storage of cytokines in concentrated filter extract solutions as compared to storage of dry filters. Conclusions Use of filter collection methods resulted in significantly higher efficiency of collection than the two aerosol-to-liquid samplers evaluated in our study. The results of this study provide the foundation for a potential new technique to evaluate biomarkers of inflammation in exhaled breath samples. PMID:22574123

Trajectory optimization and guidance for an aerospace plane

NASA Technical Reports Server (NTRS)

Mease, Kenneth D.; Vanburen, Mark A.

1989-01-01

The first step in the approach to developing guidance laws for a horizontal take-off, air breathing single-stage-to-orbit vehicle is to characterize the minimum-fuel ascent trajectories. The capability to generate constrained, minimum fuel ascent trajectories for a single-stage-to-orbit vehicle was developed. A key component of this capability is the general purpose trajectory optimization program OTIS. The pre-production version, OTIS 0.96 was installed and run on a Convex C-1. A propulsion model was developed covering the entire flight envelope of a single-stage-to-orbit vehicle. Three separate propulsion modes, corresponding to an after burning turbojet, a ramjet and a scramjet, are used in the air breathing propulsion phase. The Generic Hypersonic Aerodynamic Model Example aerodynamic model of a hypersonic air breathing single-stage-to-orbit vehicle was obtained and implemented. Preliminary results pertaining to the effects of variations in acceleration constraints, available thrust level and fuel specific impulse on the shape of the minimum-fuel ascent trajectories were obtained. The results show that, if the air breathing engines are sized for acceleration to orbital velocity, it is the acceleration constraint rather than the dynamic pressure constraint that is active during ascent.

Evaluation of pulmonary function using single-breath-hold dual-energy computed tomography with xenon

PubMed Central

Kyoyama, Hiroyuki; Hirata, Yusuke; Kikuchi, Satoshi; Sakai, Kosuke; Saito, Yuriko; Mikami, Shintaro; Moriyama, Gaku; Yanagita, Hisami; Watanabe, Wataru; Otani, Katharina; Honda, Norinari; Uematsu, Kazutsugu

2017-01-01

Abstract Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results. Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon–oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images. Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects. Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images reflected pulmonary function. Xenon images obtained with xenon-enhanced CT using a single-breath-hold technique can qualitatively depict pulmonary ventilation. A larger study comprising only COPD patients should be conducted, as xenon-enhanced CT is expected to be a promising technique for the management of COPD. PMID:28099359

Evaluation of pulmonary function using single-breath-hold dual-energy computed tomography with xenon: Results of a preliminary study.

PubMed

Kyoyama, Hiroyuki; Hirata, Yusuke; Kikuchi, Satoshi; Sakai, Kosuke; Saito, Yuriko; Mikami, Shintaro; Moriyama, Gaku; Yanagita, Hisami; Watanabe, Wataru; Otani, Katharina; Honda, Norinari; Uematsu, Kazutsugu

2017-01-01

Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results.Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon-oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images.Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects.Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images reflected pulmonary function. Xenon images obtained with xenon-enhanced CT using a single-breath-hold technique can qualitatively depict pulmonary ventilation. A larger study comprising only COPD patients should be conducted, as xenon-enhanced CT is expected to be a promising technique for the management of COPD.

Automatic detection of respiration rate from ambulatory single-lead ECG.

PubMed

Boyle, Justin; Bidargaddi, Niranjan; Sarela, Antti; Karunanithi, Mohan

2009-11-01

Ambulatory electrocardiography is increasingly being used in clinical practice to detect abnormal electrical behavior of the heart during ordinary daily activities. The utility of this monitoring can be improved by deriving respiration, which previously has been based on overnight apnea studies where patients are stationary, or the use of multilead ECG systems for stress testing. We compared six respiratory measures derived from a single-lead portable ECG monitor with simultaneously measured respiration air flow obtained from an ambulatory nasal cannula respiratory monitor. Ten controlled 1-h recordings were performed covering activities of daily living (lying, sitting, standing, walking, jogging, running, and stair climbing) and six overnight studies. The best method was an average of a 0.2-0.8 Hz bandpass filter and RR technique based on lengthening and shortening of the RR interval. Mean error rates with the reference gold standard were +/-4 breaths per minute (bpm) (all activities), +/-2 bpm (lying and sitting), and +/-1 breath per minute (overnight studies). Statistically similar results were obtained using heart rate information alone (RR technique) compared to the best technique derived from the full ECG waveform that simplifies data collection procedures. The study shows that respiration can be derived under dynamic activities from a single-lead ECG without significant differences from traditional methods.

TR-BREATH: Time-Reversal Breathing Rate Estimation and Detection.

PubMed

Chen, Chen; Han, Yi; Chen, Yan; Lai, Hung-Quoc; Zhang, Feng; Wang, Beibei; Liu, K J Ray

2018-03-01

In this paper, we introduce TR-BREATH, a time-reversal (TR)-based contact-free breathing monitoring system. It is capable of breathing detection and multiperson breathing rate estimation within a short period of time using off-the-shelf WiFi devices. The proposed system exploits the channel state information (CSI) to capture the miniature variations in the environment caused by breathing. To magnify the CSI variations, TR-BREATH projects CSIs into the TR resonating strength (TRRS) feature space and analyzes the TRRS by the Root-MUSIC and affinity propagation algorithms. Extensive experiment results indoor demonstrate a perfect detection rate of breathing. With only 10 s of measurement, a mean accuracy of can be obtained for single-person breathing rate estimation under the non-line-of-sight (NLOS) scenario. Furthermore, it achieves a mean accuracy of in breathing rate estimation for a dozen people under the line-of-sight scenario and a mean accuracy of in breathing rate estimation of nine people under the NLOS scenario, both with 63 s of measurement. Moreover, TR-BREATH can estimate the number of people with an error around 1. We also demonstrate that TR-BREATH is robust against packet loss and motions. With the prevailing of WiFi, TR-BREATH can be applied for in-home and real-time breathing monitoring.

Monitoring pulmonary function with superimposed pulmonary gas exchange curves from standard analyzers.

PubMed

Zar, Harvey A; Noe, Frances E; Szalados, James E; Goodrich, Michael D; Busby, Michael G

2002-01-01

A repetitive graphic display of the single breath pulmonary function can indicate changes in cardiac and pulmonary physiology brought on by clinical events. Parallel advances in computer technology and monitoring make real-time, single breath pulmonary function clinically practicable. We describe a system built from a commercially available airway gas monitor and off the shelf computer and data-acquisition hardware. Analog data for gas flow rate, O2, and CO2 concentrations are introduced into a computer through an analog-to-digital conversion board. Oxygen uptake (VO2) and carbon dioxide output (VCO2) are calculated for each breath. Inspired minus expired concentrations for O2 and CO2 are displayed simultaneously with the expired gas flow rate curve for each breath. Dead-space and alveolar ventilation are calculated for each breath and readily appreciated from the display. Graphs illustrating the function of the system are presented for the following clinical scenarios; upper airway obstruction, bronchospasm, bronchopleural fistula, pulmonary perfusion changes and inadequate oxygen delivery. This paper describes a real-time, single breath pulmonary monitoring system that displays three parameters graphed against time: expired flow rate, oxygen uptake and carbon dioxide production. This system allows for early and rapid recognition of treatable conditions that may lead to adverse events without any additional patient measurements or invasive procedures. Monitoring systems similar to the one described in this paper may lead to a higher level of patient safety without any additional patient risk.

Breath-hold black-blood T1rho mapping improves liver T1rho quantification in healthy volunteers.

PubMed

Wáng, Yì Xiáng J; Deng, Min; Lo, Gladys G; Liang, Dong; Yuan, Jing; Chen, Weitian

2018-03-01

Background Recent researches suggest that T1rho may be a non-invasive and quantitative technique for detecting and grading liver fibrosis. Purpose To compare a multi-breath-hold bright-blood fast gradient echo (GRE) imaging and a single breath-hold single-shot fast spin echo (FSE) imaging with black-blood effect for liver parenchyma T1rho measurement and to study liver physiological T1rho value in healthy volunteers. Material and Methods The institutional Ethics Committee approved this study. 28 healthy participants (18 men, 10 women; age = 29.6 ± 5.1 years) underwent GRE liver T1rho imaging, and 20 healthy participants (10 men, 10 women; age = 36.9 ± 10.3 years) underwent novel black-blood FSE liver T1rho imaging, both at 3T with spin-lock frequency of 500 Hz. The FSE technique allows simultaneous acquisition of four spin lock times (TSLs; 1 ms, 10 ms, 30 ms, 50msec) in 10 s. Results For FSE technique the intra-scan repeatability intraclass correlation coefficient (ICC) was 0.98; while the inter-scan reproducibility ICC was 0.82 which is better than GRE technique's 0.76. Liver T1rho value in women tended to have a higher value than T1rho values in men (FSE: 42.28 ± 4.06 ms for women and 39.13 ± 2.12 ms for men; GRE: 44.44 ± 1.62 ms for women and 42.36 ± 2.00 ms for men) and FSE technique showed liver T1rho value decreased slightly as age increased. Conclusion Single breath-hold black-blood FSE sequence has better scan-rescan reproducibility than multi-breath-hold bright-blood GRE sequence. Gender and age dependence of liver T1rho in healthy participants is observed, with young women tending to have a higher T1rho measurement.

Oxygen Uptake Efficiency Plateau Best Predicts Early Death in Heart Failure

PubMed Central

Hansen, James E.; Stringer, William W.

2012-01-01

Background: The responses of oxygen uptake efficiency (ie, oxygen uptake/ventilation = V˙o2/V˙e) and its highest plateau (OUEP) during incremental cardiopulmonary exercise testing (CPET) in patients with chronic left heart failure (HF) have not been previously reported. We planned to test the hypothesis that OUEP during CPET is the best single predictor of early death in HF. Methods: We evaluated OUEP, slope of V˙o2 to log(V˙e) (oxygen uptake efficiency slope), oscillatory breathing, and all usual resting and CPET measurements in 508 patients with low-ejection-fraction (< 35%) HF. Each had further evaluations at other sites, including cardiac catheterization. Outcomes were 6-month all-reason mortality and morbidity (death or > 24 h cardiac hospitalization). Statistical analyses included area under curve of receiver operating characteristics, ORs, univariate and multivariate Cox regression, and Kaplan-Meier plots. Results: OUEP, which requires only moderate exercise, was often reduced in patients with HF. A low % predicted OUEP was the single best predictor of mortality (P < .0001), with an OR of 13.0 (P < .001). When combined with oscillatory breathing, the OR increased to 56.3, superior to all other resting or exercise parameters or combinations of parameters. Other statistical analyses and morbidity analysis confirmed those findings. Conclusions: OUEP is often reduced in patients with HF. Low % predicted OUEP (< 65% predicted) is the single best predictor of early death, better than any other CPET or other cardiovascular measurement. Paired with oscillatory breathing, it is even more powerful. PMID:22030802

Crackle pitch and rate do not vary significantly during a single automated-auscultation session in patients with pneumonia, congestive heart failure, or interstitial pulmonary fibrosis.

PubMed

Vyshedskiy, Andrey; Ishikawa, Sadamu; Murphy, Raymond L H

2011-06-01

To determine the variability of crackle pitch and crackle rate during a single automated-auscultation session with a computerized 16-channel lung-sound analyzer. Forty-nine patients with pneumonia, 52 with congestive heart failure (CHF), and 18 with interstitial pulmonary fibrosis (IPF) performed breathing maneuvers in the following sequence: normal breathing, deep breathing, cough several times; deep breathing, vital-capacity maneuver, and deep breathing. From the auscultation recordings we measured the crackle pitch and crackle rate. Crackle pitch variability, expressed as a percentage of the average crackle pitch, was small in all patients and in all maneuvers: pneumonia 11%, CHF 11%, pulmonary fibrosis 7%. Crackle rate variability was also small: pneumonia 31%, CHF 32%, IPF 24%. Compared to the first deep-breathing maneuver (100%), the average crackle pitch did not significantly change following coughing (pneumonia 100%, CHF 103%, IPF 100%), the vital-capacity maneuver (pneumonia 100%, CHF 92%, IPF 104%), or during quiet breathing (pneumonia 97%, CHF 100%, IPF 104%). Similarly, the average crackle rate did not change significantly following coughing (pneumonia 105%, CHF 110%, IPF 90%) or the vital-capacity maneuver (pneumonia 102%, CHF 101%, IPF 99%). However, during normal breathing the crackle rate was significantly lower in the patients with pneumonia (74%, P < .001) and significantly higher in the patients with IPF (147%, P < .05) than it was during deep breathing. In patients with CHF the average crackle rate during normal breathing was not significantly different from that during the first deep-breathing maneuver (108%). Crackle pitch and rate were surprisingly stable in all 3 conditions. Neither crackle pitch nor crackle rate changed significantly from breath to breath or from one deep-breathing maneuver to another, even when the maneuvers were separated by cough or the vital-capacity maneuver. The observation that crackle rate is a reproducible measurement during one automated-auscultation session suggests that crackle rate can be used to follow the course of cardiopulmonary illnesses such as pneumonia, IPF, and CHF.

Evaluation of noninvasive cardiac output methods during exercise

NASA Technical Reports Server (NTRS)

Moore, Alan D.; Barrows, Linda H.; Rashid, Michael; Siconolfi, Steven F.

1992-01-01

Noninvasive techniques to estimate cardiac output (Qc) will be used during future space flight. This retrospective literature survey compared the Qc techniques of carbon dioxide rebreathing (CO2-R), CO2 single breath (CO2-S), Doppler (DOP), impedance (IM), and inert gas (IG: acetylene or nitrous oxide) to direct (DIR) assessments measured at rest and during exercise.

Breath-hold imaging of the coronary arteries using Quiescent-Interval Slice-Selective (QISS) magnetic resonance angiography: pilot study at 1.5 Tesla and 3 Tesla.

PubMed

Edelman, Robert R; Giri, S; Pursnani, A; Botelho, M P F; Li, W; Koktzoglou, I

2015-11-23

Coronary magnetic resonance angiography (MRA) is usually obtained with a free-breathing navigator-gated 3D acquisition. Our aim was to develop an alternative breath-hold approach that would allow the coronary arteries to be evaluated in a much shorter time and without risk of degradation by respiratory motion artifacts. For this purpose, we implemented a breath-hold, non-contrast-enhanced, quiescent-interval slice-selective (QISS) 2D technique. Sequence performance was compared at 1.5 and 3 Tesla using both radial and Cartesian k-space trajectories. The left coronary circulation was imaged in six healthy subjects and two patients with coronary artery disease. Breath-hold QISS was compared with T2-prepared 2D balanced steady-state free-precession (bSSFP) and free-breathing, navigator-gated 3D bSSFP. Approximately 10 2.1-mm thick slices were acquired in a single ~20-s breath-hold using two-shot QISS. QISS contrast-to-noise ratio (CNR) was 1.5-fold higher at 3 Tesla than at 1.5 Tesla. Cartesian QISS provided the best coronary-to-myocardium CNR, whereas radial QISS provided the sharpest coronary images. QISS image quality exceeded that of free-breathing 3D coronary MRA with few artifacts at either field strength. Compared with T2-prepared 2D bSSFP, multi-slice capability was not restricted by the specific absorption rate at 3 Tesla and pericardial fluid signal was better suppressed. In addition to depicting the coronary arteries, QISS could image intra-cardiac structures, pericardium, and the aortic root in arbitrary slice orientations. Breath-hold QISS is a simple, versatile, and time-efficient method for coronary MRA that provides excellent image quality at both 1.5 and 3 Tesla. Image quality exceeded that of free-breathing, navigator-gated 3D MRA in a much shorter scan time. QISS also allowed rapid multi-slice bright-blood, diastolic phase imaging of the heart, which may have complementary value to multi-phase cine imaging. We conclude that, with further clinical validation, QISS might provide an efficient alternative to commonly used free-breathing coronary MRA techniques.

Apparent diffusion coefficient of hyperpolarized (3)He with minimal influence of the residual gas in small animals.

PubMed

Carrero-González, L; Kaulisch, T; Ruiz-Cabello, J; Pérez-Sánchez, J M; Peces-Barba, G; Stiller, D; Rodríguez, I

2012-09-01

The apparent diffusion coefficient (ADC) of hyperpolarized (HP) gases is a parameter that reflects changes in lung microstructure. However, ADC is dependent on many physiological and experimental variables that need to be controlled or specified in order to ensure the reliability and reproducibility of this parameter. A single breath-hold experiment is desirable in order to reduce the amount of consumed HP gas. The application of a positive end-expiratory pressure (PEEP) causes an increase in the residual gas volume. Depending on the applied PEEP, the ratio between the incoming and residual gas volumes will change and the ADC will vary, as long as both gases do not have the same diffusion coefficient. The most standard method for human applications uses air for breathing and a bolus of pure HP (3)He for MRI data acquisition. By applying this method in rats, we have demonstrated that ADC values are strongly dependent on the applied PEEP, and therefore on the residual gas volume in the lung. This outcome will play an important role in studies concerning certain diseases, such as emphysema, which is characterized by an increase in the residual volume. Ventilation with an oxygen-helium mixture (VOHeM) is a proposed single breath-hold method that uses two different gas mixtures (O(2)-(4)He for ventilation and HP (3)He-N(2) for imaging). The concentration of each gas in its respective mixture was calculated in order to obtain the same diffusion coefficient in both mixtures. ADCs obtained from VOHeM are independent of PEEP, thus minimizing the effect of the different residual volumes. Copyright © 2012 John Wiley & Sons, Ltd.

'Breath figure' PLGA films as implant coatings for controlled drug release

NASA Astrophysics Data System (ADS)

Ponnusamy, Thiruselvam

The breath figure method is a versatile and facile approach of generating ordered micro and nanoporous structures in polymeric materials. When a polymer solution (dissolved in a high vapor pressure organic solvent) is evaporated out in the presence of a moist air stream, the evaporative cooling effect causes the condensation and nucleation of water droplets onto the polymer solution surface. This leads to the formation of an imprinted porous structure upon removal of the residual solvent and water. The facile removal of the water droplet template leaving its structural imprint is a specifically appealing aspect of the breath figure film technology. The first part of the dissertation work involves the fabrication of drug loaded breath figure thin films and its utilization as a controlled drug release carrier and biomaterial scaffold. In a single fabrication step, single layer/multilayer porous thin films were designed and developed by combining the breath figure process and a modified spin or dip coating technique. Using biodegradable polymers such as poly (lactic-co-glycolic acid) (PLGA) and poly (ethylene glycol) (PEG), drug loaded films were fabricated onto FDA approved medical devices (the Glaucoma drainage device and the Surgical hernia mesh). The porosity of the films is in the range of 2-4 microm as characterized by scanning electron microscope. The drug coated medical implants were characterized for their surface and bulk morphology, the degradation rate of the film, drug release rate and cell cytotoxicity. The results suggest that the use of breath figure morphologies in biodegradable polymer films adds an additional level of control to drug release. In comparison to non-porous films, the breath figure films showed an increased degradation and enhanced drug release. Furthermore, the porous nature of the film was investigated as a biomaterial scaffold to construct three dimensional in vitro tissue model systems. The breath figure film with interconnected pores facilitates cell infiltration and tissue remodelling in vitro, suggesting its high potential in regenerative medicine and tissue engineering applications. In the second part of the dissertation, the versatility of breath figure polymers was explored as a reverse template to create micropatterned soft materials. Unlike traditional lithographic masters, the breath figure assembly is a simple and cost-effective approach to create micro/nano sized "bead" like uniform patterns on the surface of hydrogels and biopolymers. By incorporating iron nanoparticles into the pores, this technique was extended to form hydrogels decorated with nanoparticles specifically in the pattern. The morphology features and the functional characteristics were demonstrated through scanning electron microscopy. The potential applications of these micro-fabricated materials in biosensors and cell culture substrates are outlined.

Improved workflow for quantification of left ventricular volumes and mass using free-breathing motion corrected cine imaging.

PubMed

Cross, Russell; Olivieri, Laura; O'Brien, Kendall; Kellman, Peter; Xue, Hui; Hansen, Michael

2016-02-25

Traditional cine imaging for cardiac functional assessment requires breath-holding, which can be problematic in some situations. Free-breathing techniques have relied on multiple averages or real-time imaging, producing images that can be spatially and/or temporally blurred. To overcome this, methods have been developed to acquire real-time images over multiple cardiac cycles, which are subsequently motion corrected and reformatted to yield a single image series displaying one cardiac cycle with high temporal and spatial resolution. Application of these algorithms has required significant additional reconstruction time. The use of distributed computing was recently proposed as a way to improve clinical workflow with such algorithms. In this study, we have deployed a distributed computing version of motion corrected re-binning reconstruction for free-breathing evaluation of cardiac function. Twenty five patients and 25 volunteers underwent cardiovascular magnetic resonance (CMR) for evaluation of left ventricular end-systolic volume (ESV), end-diastolic volume (EDV), and end-diastolic mass. Measurements using motion corrected re-binning were compared to those using breath-held SSFP and to free-breathing SSFP with multiple averages, and were performed by two independent observers. Pearson correlation coefficients and Bland-Altman plots tested agreement across techniques. Concordance correlation coefficient and Bland-Altman analysis tested inter-observer variability. Total scan plus reconstruction times were tested for significant differences using paired t-test. Measured volumes and mass obtained by motion corrected re-binning and by averaged free-breathing SSFP compared favorably to those obtained by breath-held SSFP (r = 0.9863/0.9813 for EDV, 0.9550/0.9685 for ESV, 0.9952/0.9771 for mass). Inter-observer variability was good with concordance correlation coefficients between observers across all acquisition types suggesting substantial agreement. Both motion corrected re-binning and averaged free-breathing SSFP acquisition and reconstruction times were shorter than breath-held SSFP techniques (p < 0.0001). On average, motion corrected re-binning required 3 min less than breath-held SSFP imaging, a 37% reduction in acquisition and reconstruction time. The motion corrected re-binning image reconstruction technique provides robust cardiac imaging that can be used for quantification that compares favorably to breath-held SSFP as well as multiple average free-breathing SSFP, but can be obtained in a fraction of the time when using cloud-based distributed computing reconstruction.

Quantification of liver fat with respiratory-gated quantitative chemical shift encoded MRI.

PubMed

Motosugi, Utaroh; Hernando, Diego; Bannas, Peter; Holmes, James H; Wang, Kang; Shimakawa, Ann; Iwadate, Yuji; Taviani, Valentina; Rehm, Jennifer L; Reeder, Scott B

2015-11-01

To evaluate free-breathing chemical shift-encoded (CSE) magnetic resonance imaging (MRI) for quantification of hepatic proton density fat-fraction (PDFF). A secondary purpose was to evaluate hepatic R2* values measured using free-breathing quantitative CSE-MRI. Fifty patients (mean age, 56 years) were prospectively recruited and underwent the following four acquisitions to measure PDFF and R2*; 1) conventional breath-hold CSE-MRI (BH-CSE); 2) respiratory-gated CSE-MRI using respiratory bellows (BL-CSE); 3) respiratory-gated CSE-MRI using navigator echoes (NV-CSE); and 4) single voxel MR spectroscopy (MRS) as the reference standard for PDFF. Image quality was evaluated by two radiologists. MRI-PDFF measured from the three CSE-MRI methods were compared with MRS-PDFF using linear regression. The PDFF and R2* values were compared using two one-sided t-test to evaluate statistical equivalence. There was no significant difference in the image quality scores among the three CSE-MRI methods for either PDFF (P = 1.000) or R2* maps (P = 0.359-1.000). Correlation coefficients (95% confidence interval [CI]) for the PDFF comparisons were 0.98 (0.96-0.99) for BH-, 0.99 (0.97-0.99) for BL-, and 0.99 (0.98-0.99) for NV-CSE. The statistical equivalence test revealed that the mean difference in PDFF and R2* between any two of the three CSE-MRI methods was less than ±1 percentage point (pp) and ±5 s(-1) , respectively (P < 0.046). Respiratory-gated CSE-MRI with respiratory bellows or navigator echo are feasible methods to quantify liver PDFF and R2* and are as valid as the standard breath-hold technique. © 2015 Wiley Periodicals, Inc.

An Ultrasound Image-Based Dynamic Fusion Modeling Method for Predicting the Quantitative Impact of In Vivo Liver Motion on Intraoperative HIFU Therapies: Investigations in a Porcine Model

PubMed Central

N'Djin, W. Apoutou; Chapelon, Jean-Yves; Melodelima, David

2015-01-01

Organ motion is a key component in the treatment of abdominal tumors by High Intensity Focused Ultrasound (HIFU), since it may influence the safety, efficacy and treatment time. Here we report the development in a porcine model of an Ultrasound (US) image-based dynamic fusion modeling method for predicting the effect of in vivo motion on intraoperative HIFU treatments performed in the liver in conjunction with surgery. A speckle tracking method was used on US images to quantify in vivo liver motions occurring intraoperatively during breathing and apnea. A fusion modeling of HIFU treatments was implemented by merging dynamic in vivo motion data in a numerical modeling of HIFU treatments. Two HIFU strategies were studied: a spherical focusing delivering 49 juxtapositions of 5-second HIFU exposures and a toroidal focusing using 1 single 40-second HIFU exposure. Liver motions during breathing were spatially homogenous and could be approximated to a rigid motion mainly encountered in the cranial-caudal direction (f = 0.20Hz, magnitude >13mm). Elastic liver motions due to cardiovascular activity, although negligible, were detectable near millimeter-wide sus-hepatic veins (f = 0.96Hz, magnitude <1mm). The fusion modeling quantified the deleterious effects of respiratory motions on the size and homogeneity of a standard “cigar-shaped” millimetric lesion usually predicted after a 5-second single spherical HIFU exposure in stationary tissues (Dice Similarity Coefficient: DSC<45%). This method assessed the ability to enlarge HIFU ablations during respiration, either by juxtaposing “cigar-shaped” lesions with spherical HIFU exposures, or by generating one large single lesion with toroidal HIFU exposures (DSC>75%). Fusion modeling predictions were preliminarily validated in vivo and showed the potential of using a long-duration toroidal HIFU exposure to accelerate the ablation process during breathing (from 0.5 to 6 cm3·min-1). To improve HIFU treatment control, dynamic fusion modeling may be interesting for assessing numerically focusing strategies and motion compensation techniques in more realistic conditions. PMID:26398366

Single-shot turbo spin echo acquisition for in vivo cardiac diffusion MRI.

PubMed

Edalati, Masoud; Lee, Gregory R; Hui Wang; Taylor, Michael D; Li, Yu Y

2016-08-01

Diffusion MRI offers the ability to noninvasively characterize the microstructure of myocardium tissue and detect disease related pathology in cardiovascular examination. This study investigates the feasibility of in vivo cardiac diffusion MRI under free-breathing condition. A high-speed imaging technique, correlation imaging, is used to enable single-shot turbo spin echo for free-breathing cardiac data acquisition. The obtained in vivo cardiac diffusion-weighted images illustrate robust image quality and minor geometry distortions. The resultant diffusion scalar maps show reliable quantitative values consistent with those previously published in the literature. It is demonstrated that this technique has the potential for in vivo free-breathing cardiac diffusion MRI.

Exhaled breath condensate – from an analytical point of view

PubMed Central

Dodig, Slavica; Čepelak, Ivana

2013-01-01

Over the past three decades, the goal of many researchers is analysis of exhaled breath condensate (EBC) as noninvasively obtained sample. A total quality in laboratory diagnostic processes in EBC analysis was investigated: pre-analytical (formation, collection, storage of EBC), analytical (sensitivity of applied methods, standardization) and post-analytical (interpretation of results) phases. EBC analysis is still used as a research tool. Limitations referred to pre-analytical, analytical, and post-analytical phases of EBC analysis are numerous, e.g. low concentrations of EBC constituents, single-analyte methods lack in sensitivity, and multi-analyte has not been fully explored, and reference values are not established. When all, pre-analytical, analytical and post-analytical requirements are met, EBC biomarkers as well as biomarker patterns can be selected and EBC analysis can hopefully be used in clinical practice, in both, the diagnosis and in the longitudinal follow-up of patients, resulting in better outcome of disease. PMID:24266297

Fetal oxygenation measurement using wireless near infrared spectroscopy

NASA Astrophysics Data System (ADS)

Macnab, Andrew; Shadgan, Babak; Janssen, Patricia; Rurak, Dan

2012-03-01

Background: Fetal well-being is determined in large part by how well the placenta is able to supply oxygen and nutrients, but current technology is unable to directly measure how well a placenta functions. Near-infrared spectroscopy (NIRS) utilizes optical methods to measure tissue oxygenation. This pilot project evaluated the feasibility of NIRS for fetal monitoring through the maternal abdominal wall using a sheep model. Methods: A miniature wireless 2-wavelength NIRS device was placed on the abdominal skin over the placenta of a pregnant ewe whose fetus had been chronically catheterized to allow arterial sampling for measurement of arterial oxygen saturation. The NIRS device has 3-paired light emitting diodes and a single photodiode detector; allowing measurement of an index of tissue oxygen saturation (TSI%). Fetal limb TSI% values were compared before and during fetal breathing movements. Correlation was made during these events between arterial values and placental TSI% monitored continuously in real time. Results: Serial measurements were obtained in a single experiment. The correlation between transcutaneous NIRS derived TSI% and direct arterial oxygen saturation was very high (R2=0.86). Measures of fetal limb TSI% were declined after episodes of fetal breathing (P<0.005). Conclusions: This correlation suggests that NIRS is sensitive enough to detect changes in fetal tissue oxygenation noninvasively through the maternal abdominal wall in real-time in a sheep model. NIRS data confirmed that fetal breathing movements decrease arterial oxygen saturation in fetal lambs. If validated by further study this optical methodology could be applied as means of monitoring fetal wellbeing in humans.

Comparison of breath gases, including acetone, with blood glucose and blood ketones in children and adolescents with type 1 diabetes.

PubMed

Blaikie, Tom P J; Edge, Julie A; Hancock, Gus; Lunn, Daniel; Megson, Clare; Peverall, Rob; Richmond, Graham; Ritchie, Grant A D; Taylor, David

2014-11-25

Previous studies have suggested that breath gases may be related to simultaneous blood glucose and blood ketone levels in adults with type 2 and type 1 diabetes. The aims of this study were to investigate these relationships in children and young people with type 1 diabetes in order to assess the efficacy of a simple breath test as a non-invasive means of diabetes management. Gases were collected in breath bags and measurements were compared with capillary blood glucose and ketone levels taken at the same time on a single visit to a routine hospital clinic in 113 subjects (59 male, age 7 years 11 months-18 years 3 months) with type 1 diabetes. The patients were well-controlled with relatively low concentrations of the blood ketone measured (β hydroxybutyrate, 0-0.4 mmol l(-1)). Breath acetone levels were found to increase with blood β hydroxybutyrate levels and a significant relationship was found between the two (Spearman's rank correlation ρ = 0.364, p < 10(-4)). A weak positive relationship was found between blood glucose and breath acetone (ρ = 0.16, p = 0.1), but led to the conclusion that single breath measurements of acetone do not provide a good measure of blood glucose levels in this cohort. This result suggests a potential to develop breath gas analysis to provide an alternative to blood testing for ketone measurement, for example to assist with the management of type 1 diabetes.

Design options for advanced manned launch systems

NASA Astrophysics Data System (ADS)

Freeman, Delma C.; Talay, Theodore A.; Stanley, Douglas O.; Lepsch, Roger A.; Wilhite, Alan W.

1995-03-01

Various concepts for advanced manned launch systems are examined for delivery missions to space station and polar orbit. Included are single-and two-stage winged systems with rocket and/or air-breathing propulsion systems. For near-term technologies, two-stage reusable rocket systems are favored over single-stage rocket or two-stage air-breathing/rocket systems. Advanced technologies enable viable single-stage-to-orbit (SSTO) concepts. Although two-stage rocket systems continue to be lighter in dry weight than SSTO vehicles, advantages in simpler operations may make SSTO vehicles more cost-effective over the life cycle. Generally, rocket systems maintain a dry-weight advantage over air-breathing systems at the advanced technology levels, but to a lesser degree than when near-term technologies are used. More detailed understanding of vehicle systems and associated ground and flight operations requirements and procedures is essential in determining quantitative discrimination between these latter concepts.

Research Technology

NASA Image and Video Library

2004-04-15

Pictured is a component of the Rocket Based Combined Cycle (RBCC) engine. This engine was designed to ultimately serve as the near term basis for Two Stage to Orbit (TSTO) air breathing propulsion systems and ultimately a Single Stage to Orbit (SSTO) air breathing propulsion system.

Breathing exercises for dysfunctional breathing/hyperventilation syndrome in adults.

PubMed

Jones, Mandy; Harvey, Alex; Marston, Louise; O'Connell, Neil E

2013-05-31

Dysfunctional breathing/hyperventilation syndrome (DB/HVS) is a respiratory disorder, psychologically or physiologically based, involving breathing too deeply and/or too rapidly (hyperventilation) or erratic breathing interspersed with breath-holding or sighing (DB). DB/HVS can result in significant patient morbidity and an array of symptoms including breathlessness, chest tightness, dizziness, tremor and paraesthesia. DB/HVS has an estimated prevalence of 9.5% in the general adult population, however, there is little consensus regarding the most effective management of this patient group. (1) To determine whether breathing exercises in patients with DB/HVS have beneficial effects as measured by quality of life indices (2) To determine whether there are any adverse effects of breathing exercises in patients with DB/HVS SEARCH METHODS: We identified trials for consideration using both electronic and manual search strategies. We searched CENTRAL, MEDLINE, EMBASE, and four other databases. The latest search was in February 2013. We planned to include randomised, quasi-randomised or cluster randomised controlled trials (RCTs) in which breathing exercises, or a combined intervention including breathing exercises as a key component, were compared with either no treatment or another therapy that did not include breathing exercises in patients with DB/HVS. Observational studies, case studies and studies utilising a cross-over design were not eligible for inclusion.We considered any type of breathing exercise for inclusion in this review, such as breathing control, diaphragmatic breathing, yoga breathing, Buteyko breathing, biofeedback-guided breathing modification, yawn/sigh suppression. Programs where exercises were either supervised or unsupervised were eligible as were relaxation techniques and acute-episode management, as long as it was clear that breathing exercises were a key component of the intervention.We excluded any intervention without breathing exercises or where breathing exercises were not key to the intervention. Two review authors independently checked search results for eligible studies, assessed all studies that appeared to meet the selection criteria and extracted data. We used standard procedures recommended by The Cochrane Collaboration. We included a single RCT assessed at unclear risk of bias, which compared relaxation therapy (n = 15) versus relaxation therapy and breathing exercises (n = 15) and a no therapy control group (n = 15).Quality of life was not an outcome measure in this RCT, and no numerical data or statistical analysis were presented in this paper. A significant reduction in the frequency and severity of hyperventilation attacks in the breathing exercise group compared with the control group was reported. In addition, a significant difference in frequency and severity of hyperventilation attacks between the breathing and relaxation group was reported. However, no information could be extracted from the paper regarding the size of the treatment effects. The results of this systematic review are unable to inform clinical practice, based on the inclusion of only one small, poorly reported RCT. There is no credible evidence regarding the effectiveness of breathing exercises for the clinical symptoms of DB/HVS. It is currently unknown whether these interventions offer any added value in this patient group or whether specific types of breathing exercise demonstrate superiority over others. Given that breathing exercises are frequently used to treat DB/HVS, there is an urgent need for further well designed clinical trials in this area. Future trials should conform to the CONSORT statement for standards of reporting and use appropriate, validated outcome measures. Trial reports should also ensure full disclosure of data for all important clinical outcomes.

A Gaussian method to improve work-of-breathing calculations.

PubMed

Petrini, M F; Evans, J N; Wall, M A; Norman, J R

1995-01-01

The work of breathing is a calculated index of pulmonary function in ventilated patients that may be useful in deciding when to wean and when to extubate. However, the accuracy of the calculated work of breathing of the patient (WOBp) can suffer from artifacts introduced by coughing, swallowing, and other non-breathing maneuvers. The WOBp in this case will include not only the usual work of inspiration, but also the work of performing these non-breathing maneuvers. The authors developed a method to objectively eliminate the calculated work of these movements from the work of breathing, based on fitting to a Gaussian curve the variable P, which is obtained from the difference between the esophageal pressure change and the airway pressure change during each breath. In spontaneously breathing adults the normal breaths fit the Gaussian curve, while breaths that contain non-breathing maneuvers do not. In this Gaussian breath-elimination method (GM), breaths that are two standard deviations from that mean obtained by the fit are eliminated. For normally breathing control adult subjects, GM had little effect on WOBp, reducing it from 0.49 to 0.47 J/L (n = 8), while there was a 40% reduction in the coefficient of variation. Non-breathing maneuvers were simulated by coughing, which increased WOBp to 0.88 (n = 6); with the GM correction, WOBp was 0.50 J/L, a value not significantly different from that of normal breathing. Occlusion also increased WOBp to 0.60 J/L, but GM-corrected WOBp was 0.51 J/L, a normal value. As predicted, doubling the respiratory rate did not change the WOBp before or after the GM correction.(ABSTRACT TRUNCATED AT 250 WORDS)

A cross-sectional study of breath acetone based on diabetic metabolic disorders.

PubMed

Li, Wenwen; Liu, Yong; Lu, Xiaoyong; Huang, Yanping; Liu, Yu; Cheng, Shouquan; Duan, Yixiang

2015-02-26

Breath acetone is a known biomarker for diabetes mellitus in breath analysis. In this work, a cross-sectional study of breath acetone based on clinical metabolic disorders of type 2 diabetes mellitus (T2DM) was carried out. Breath acetone concentrations of 113 T2DM patients and 56 apparently healthy individuals were measured at a single time point. Concentrations varied from 0.22 to 9.41 ppmv (mean 1.75 ppmv) for T2DM, which were significantly higher than those for normal controls (ranged from 0.32 to 1.96 ppmv, mean 0.72 ppmv, p = 0.008). Observations in our work revealed that breath acetone concentrations elevated to different degrees, along with the abnormality of blood glucose, glycated hemoglobin (HbA1c), triglyceride and cholesterol. Breath acetone showed obviously positive correlations with blood ketone and urine ketone. Possible metabolic relations between breath acetone and diabetic disorders were also discussed. This work aimed at giving an overall assessment of breath acetone from the perspective of clinical parameters for type 2 diabetes.

Emptying patterns of the lung studied by multiple-breath N2 washout

NASA Technical Reports Server (NTRS)

Lewis, S. M.

1978-01-01

Changes in the nitrogen concentration seen during the single-breath nitrogen washout reflect changes in relative flow (ventilation) from units with differing ventilation/volume ratios. The multiple-breath washout provides sufficient data on ventilation for units with varying ventilation/volume ratios to be plotted as a function of the volume expired. Flow from the dead space may also be determined. In young normals the emptying patterns are narrow and unimodal throughout the alveolar plateau with little or no flow from the dead space at the end of the breath. Older normals show more flow from the dead space, particularly toward the end of the breath, and some show a high ventilation/volume ratio mode early in the breath. Patients with obstructive lung disease have a high flow from the dead space which is present throughout the breath. A well ventilated mode at the end of the breath is seen in some obstructed subjects. Patients with cystic fibrosis showed a poorly ventilated mode appearing at the end of the breath as well as a very high dead space.

Effects of microgravity on tissue perfusion and the efficacy of astronaut denitrogenation for EVA

NASA Technical Reports Server (NTRS)

Gerth, Wayne A.; Vann, Richard D.; Leatherman, Nelson E.; Feezor, Michael D.

1987-01-01

A potentially flight-applicable, breath-by-breath method for measuring N2 elimination from human subjects breathing 100 percent O2 for 2-3 hr periods has been developed. The present report describes this development with particular emphasis on required methodological accuracy and its achievement in view of certain properties of mass spectrometer performance. A method for the breath-by-breath analysis of errors in measured N2 elimination profiles is also described.

A Portable Real-Time Ringdown Breath Acetone Analyzer: Toward Potential Diabetic Screening and Management

PubMed Central

Jiang, Chenyu; Sun, Meixiu; Wang, Zhennan; Chen, Zhuying; Zhao, Xiaomeng; Yuan, Yuan; Li, Yingxin; Wang, Chuji

2016-01-01

Breath analysis has been considered a suitable tool to evaluate diseases of the respiratory system and those that involve metabolic changes, such as diabetes. Breath acetone has long been known as a biomarker for diabetes. However, the results from published data by far have been inconclusive regarding whether breath acetone is a reliable index of diabetic screening. Large variations exist among the results of different studies because there has been no “best-practice method” for breath-acetone measurements as a result of technical problems of sampling and analysis. In this mini-review, we update the current status of our development of a laser-based breath acetone analyzer toward real-time, one-line diabetic screening and a point-of-care instrument for diabetic management. An integrated standalone breath acetone analyzer based on the cavity ringdown spectroscopy technique has been developed. The instrument was validated by using the certificated gas chromatography-mass spectrometry. The linear fittings suggest that the obtained acetone concentrations via both methods are consistent. Breath samples from each individual subject under various conditions in total, 1257 breath samples were taken from 22 Type 1 diabetic (T1D) patients, 312 Type 2 diabetic (T2D) patients, which is one of the largest numbers of T2D subjects ever used in a single study, and 52 non-diabetic healthy subjects. Simultaneous blood glucose (BG) levels were also tested using a standard diabetic management BG meter. The mean breath acetone concentrations were determined to be 4.9 ± 16 ppm (22 T1D), and 1.5 ± 1.3 ppm (312 T2D), which are about 4.5 and 1.4 times of the one in the 42 non-diabetic healthy subjects, 1.1 ± 0.5 ppm, respectively. A preliminary quantitative correlation (R = 0.56, p < 0.05) between the mean individual breath acetone concentration and the mean individual BG levels does exist in 20 T1D subjects with no ketoacidosis. No direct correlation is observed in T1D subjects, T2D subjects, and healthy subjects. The results from a relatively large number of subjects tested indicate that an elevated mean breath acetone concentration exists in diabetic patients in general. Although many physiological parameters affect breath acetone, under a specifically controlled condition fast (<1 min) and portable breath acetone measurement can be used for screening abnormal metabolic status including diabetes, for point-of-care monitoring status of ketone bodies which have the signature smell of breath acetone, and for breath acetone related clinical studies requiring a large number of tests. PMID:27483281

Respiratory rate extraction from pulse oximeter and electrocardiographic recordings.

PubMed

Lee, Jinseok; Florian, John P; Chon, Ki H

2011-11-01

We present an algorithm of respiratory rate extraction using particle filter (PF), which is applicable to both photoplethysmogram (PPG) and electrocardiogram (ECG) signals. For the respiratory rate estimation, 1 min data are analyzed with combination of a PF method and an autoregressive model where among the resultant coefficients, the corresponding pole angle with the highest magnitude is searched since this reflects the closest approximation of the true breathing rate. The PPG data were collected from 15 subjects with the metronome breathing rate ranging from 24 to 36 breaths per minute in the supine and upright positions. The ECG data were collected from 11 subjects with spontaneous breathing ranging from 36 to 60 breaths per minute during treadmill exercises. Our method was able to accurately extract respiratory rates for both metronome and spontaneous breathing even during strenuous exercises. More importantly, despite slow increases in breathing rates concomitant with greater exercise vigor with time, our method was able to accurately track these progressive increases in respiratory rates. We quantified the accuracy of our method by using the mean, standard deviation and interquartile range of the error rates which all reflected high accuracy in estimating the true breathing rates. We are not aware of any other algorithms that are able to provide accurate respiratory rates directly from either ECG signals or PPG signals with spontaneous breathing during strenuous exercises. Our method is near real-time realizable because the computational time on 1 min data segment takes only 10 ms on a 2.66 GHz Intel Core2 microprocessor; the data are subsequently shifted every 10 s to obtain near-continuous breathing rates. This is an attractive feature since most other techniques require offline data analyses to estimate breathing rates.

Air-Breathing Launch Vehicle Technology Being Developed

NASA Technical Reports Server (NTRS)

Trefny, Charles J.

2003-01-01

Of the technical factors that would contribute to lowering the cost of space access, reusability has high potential. The primary objective of the GTX program is to determine whether or not air-breathing propulsion can enable reusable single-stage-to-orbit (SSTO) operations. The approach is based on maturation of a reference vehicle design with focus on the integration and flight-weight construction of its air-breathing rocket-based combined-cycle (RBCC) propulsion system.

SU-E-J-178: A Normalization Method Can Remove Discrepancy in Ventilation Function Due to Different Breathing Patterns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qu, H; Yu, N; Stephans, K

2014-06-01

Purpose: To develop a normalization method to remove discrepancy in ventilation function due to different breathing patterns. Methods: Twenty five early stage non-small cell lung cancer patients were included in this study. For each patient, a ten phase 4D-CT and the voluntarily maximum inhale and exhale CTs were acquired clinically and retrospectively used for this study. For each patient, two ventilation maps were calculated from voxel-to-voxel CT density variations from two phases of the quiet breathing and two phases of the extreme breathing. For the quiet breathing, 0% (inhale) and 50% (exhale) phases from 4D-CT were used. An in-house toolmore » was developed to calculate and display the ventilation maps. To enable normalization, the whole lung of each patient was evenly divided into three parts in the longitude direction at a coronal image with a maximum lung cross section. The ratio of cumulated ventilation from the top one-third region to the middle one-third region of the lung was calculated for each breathing pattern. Pearson's correlation coefficient was calculated on the ratios of the two breathing patterns for the group. Results: For each patient, the ventilation map from the quiet breathing was different from that of the extreme breathing. When the cumulative ventilation was normalized to the middle one-third of the lung region for each patient, the normalized ventilation functions from the two breathing patterns were consistent. For this group of patients, the correlation coefficient of the normalized ventilations for the two breathing patterns was 0.76 (p < 0.01), indicating a strong correlation in the ventilation function measured from the two breathing patterns. Conclusion: For each patient, the ventilation map is dependent of the breathing pattern. Using a regional normalization method, the discrepancy in ventilation function induced by the different breathing patterns thus different tidal volumes can be removed.« less

Application of ion chemistry and the SIFT technique to the quantitative analysis of trace gases in air and on breath

NASA Astrophysics Data System (ADS)

Smith, David; Španěl, Patrik

Our major objective in this paper is to describe a new method we have developed for the analysis of trace gases at partial pressures down to the ppb level in atmospheric air, with special emphasis on the detection and quantification of trace gases on human breath. It involves the use of our selected ion flow tube (Sift) technique which we previously developed and used extensively for the study of gas phase ionic reactions occurring in ionized media such as the terrestrial atmosphere and interstellar gas clouds. Before discussing this analytical technique we describe the results of our very recent Sift and flowing afterglow (FA) studies of the reactions of the H3O+ and OH- ions, of their hydrates H3O+(H2O)1,2,3 and OH- (H2O)1,2, and of NO+ and O2+, with several hydrocarbons and oxygen-bearing organic molecules, studies that are very relevant to our trace gas analytical studies. Then follows a detailed discussion of the application of our Sift technique to trace gas analysis, after which we present some results obtained for the analyses of laboratory air, the breath of a healthy non-smoking person, the breath of a person who regularly smokes cigarettes, the complex vapours emitted by banana and onion, and the molecules present in a butane/air flame. We show how the quantitative analysis of breath can be achieved from only a single exhalation and in real time (the time response of the instrument is only about 20 ms). We also show how the time variation of breath gases over long time periods can be followed, using the decay of ethanol on the breath after the ingestion of distilled liquor as an example, yet simultaneously following several other trace gases including acetone and isoprene which are very easily detected on the breath of all individuals because of their relatively high partial pressures (typically 100 to 1000 ppb). The breath of a smoker is richer in complex molecules, some nitrogen containing organics apparently being very evident at the 5 to 50 ppb level. These results and those for banana and onion vapours and butane/air flame forcibly demonstrate the value and the scope of our Sift ion chemistry approach to the analysis of very complex gas mixtures, and that this method is accurately quantitative if the appropriate ion chemistry is properly understood.

Rocket Based Combined Cycle (RBCC) engine inlet

NASA Technical Reports Server (NTRS)

2004-01-01

Pictured is a component of the Rocket Based Combined Cycle (RBCC) engine. This engine was designed to ultimately serve as the near term basis for Two Stage to Orbit (TSTO) air breathing propulsion systems and ultimately a Single Stage to Orbit (SSTO) air breathing propulsion system.

Use of an acoustic helium analyzer for measuring lung volumes.

PubMed

Krumpe, P E; MacDannald, H J; Finley, T N; Schear, H E; Hall, J; Cribbs, D

1981-01-01

We have evaluated the use of an acoustic gas analyzer (AGA) for the measurement of total lung capacity (TLC) by single-breath helium dilution. The AGA has a rapid response time (0-90% response = 160 ms for 10% He), is linear for helium concentration of 0.1-10%, is stable over a wide range of ambient temperatures, and is small and portable. We plotted the output of the AGA vs. expired lung volume after a vital capacity breath of 10% He. However, since the AGA is sensitive to changes in speed of sound relative to air, the AGA output signal also reports an artifact due to alveolar gases. We corrected for this artifact by replotting a single-breath expiration after a vital capacity breath of room air. Mean alveolar helium concentration (HeA) was then measured by planimetry, using this alveolar gas curve as the base line. TLC was calculated using the HeA from the corrected AGA output and compared with TLC calculated from HeA simultaneously measured using a mass spectrometer (MS). In 12 normal subjects and 9 patients with chronic obstructive pulmonary disease (COPD) TLC-AGA and TLC-MS were compared by linear regression analysis; correlation coefficient (r) was 0.973 for normals and 0.968 for COPD patients (P less than 0.001). This single-breath; estimation of TLC using the corrected signal of the AGA vs. Expired volume seems ideally suited for the measurement of subdivisions of lung volume in field studies.

New method for single-breath fraction of exhaled nitric oxide measurement with improved feasibility in preschool children with asthma.

PubMed

Heijkenskjöld-Rentzhog, Charlotte; Kalm-Stephens, Pia; Nordvall, Lennart; Malinovschi, Andrei; Alving, Kjell

2015-11-01

Respiratory societies recommend use of standardized methodologies for fraction of exhaled nitric oxide (FeNO) measurements in adults and children, but in preschoolers, feasibility remains a problem. The exhalation time needed to obtain steady-state FeNO is unclear. Our primary aim was to study the feasibility of an adapted single-breath FeNO method with age-adjusted exhalation times. We also studied the association between time to steady-state NO level and height, as well as FeNO in relation to asthma and current treatment with inhaled corticosteroids (ICS). Sixty-three children aged 3-10 years performed FeNO measurements with a hand-held electrochemical device with a newly developed flow-control unit. Exhalation times were pre-adapted to age. Exhaled air was simultaneously sampled to a chemiluminescence analyzer to measure time to steady-state NO level. Eighty-one percent of the children achieved at least one approved measurement. From 4 years upwards, success rate was high (96%). Time to steady-state [NO] (median and interquartile range) was 2.5 s (2.4-3.5) at the age of 3-4 years and 3.5 s (2.7-3.8) at the age of 5-6 years. Height was associated with time to steady state (r(2) = 0.13, p = 0.02). FeNO (geometric mean [95% CI]) was higher in ICS-naïve asthmatic children (n = 19): 15.9 p.p.b. (12.2-20.9), than in both healthy controls (n = 8) 9.1 p.p.b. (6.6-12.4) and asthmatic subjects on treatment (n = 24) 11.5 p.p.b. (9.7-13.6). We found this adapted single-breath method with age-adjusted exhalation times highly feasible for children aged 4-10 years. ICS-naïve asthmatic children had FeNO levels under the current guideline cutoff level (20 p.p.b.), highlighting the importance of taking age into account when setting reference values. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Collecting Protein Biomarkers in Breath Using Electret Filters: A Preliminary Method on New Technical Model and Human Study.

PubMed

Li, Wang; Pi, Xitian; Qiao, Panpan; Liu, Hongying

2016-01-01

Biomarkers in exhaled breath are useful for respiratory disease diagnosis in human volunteers. Conventional methods that collect non-volatile biomarkers, however, necessitate an extensive dilution and sanitation processes that lowers collection efficiencies and convenience of use. Electret filter emerged in recent decade to collect virus biomarkers in exhaled breath given its simplicity and effectiveness. To investigate the capability of electret filters to collect protein biomarkers, a model that consists of an atomizer that produces protein aerosol and an electret filter that collects albumin and carcinoembryonic antigen-a typical biomarker in lung cancer development- from the atomizer is developed. A device using electret filter as the collecting medium is designed to collect human albumin from exhaled breath of 6 volunteers. Comparison of the collecting ability between the electret filter method and other 2 reported methods is finally performed based on the amounts of albumin collected from human exhaled breath. In conclusion, a decreasing collection efficiency ranging from 17.6% to 2.3% for atomized albumin aerosol and 42% to 12.5% for atomized carcinoembryonic antigen particles is found; moreover, an optimum volume of sampling human exhaled breath ranging from 100 L to 200 L is also observed; finally, the self-designed collecting device shows a significantly better performance in collecting albumin from human exhaled breath than the exhaled breath condensate method (p<0.05) but is not significantly more effective than reported 3-stage impactor method (p>0.05). In summary, electret filters are potential in collecting non-volatile biomarkers in human exhaled breath not only because it was simpler, cheaper and easier to use than traditional methods but also for its better collecting performance.

Single-breath CO2 analysis as a predictor of lung volume in a healthy animal model during controlled ventilation.

PubMed

Stenz, R I; Grenier, B; Thompson, J E; Arnold, J H

1998-08-01

To examine the utility of single-breath CO2 analysis as a measure of lung volume. A prospective, animal cohort study comparing 21 parameters derived from single-breath CO2 analysis with lung volume measurements determined by nitrogen washout in animals during controlled ventilation. An animal laboratory in a university-affiliated medical center. Seven healthy lambs. The single-breath CO2 analysis station consists of a mainstream capnometer, a variable orifice pneumotachometer, a signal processor and computer software with capability for both on- and off-line data analysis. Twenty-one derived components of the CO2 expirogram were evaluated as predictors of lung volume. Lung volume was manipulated by 3 cm H2O incremental increases in positive end-expiratory pressure from 0 to 21 cm H2O, and ranged between 147 and 942 mL. Fifty-five measurements of lung volume were available for comparison with derived variables from the CO2 expirogam. Stepwise linear regression identified four variables that were most predictive of lung volume: a) dynamic lung compliance; b) the slope of phase 3; c) the slope of phase 2 divided by the mixed expired CO2 tension; and d) airway deadspace. The multivariate equation was highly statistically significant and explained 94% of the variance (adjusted r2 =.94, p < .0001). The bias and precision of the calculated lung volume was .00 and 51, respectively. The mean percent difference for the lung volume estimate derived from the single-breath CO2 analysis station was 0.79%. Our data indicate that analysis of the CO2 expirogram can yield accurate information about lung volume. Specifically, four variables derived from a plot of expired CO2 concentration vs. expired volume predict changes in lung volume in healthy lambs with an adjusted coefficient of determination of .94. Prospective application of this technology in the setting of lung injury and rapidly changing physiology is essential in determining the clinical usefulness of the technique.

Apparatus and method for monitoring breath acetone and diabetic diagnostics

DOEpatents

Duan, Yixiang [Los Alamos, NM; Cao, Wenqing [Los Alamos, NM

2008-08-26

An apparatus and method for monitoring diabetes through breath acetone detection and quantitation employs a microplasma source in combination with a spectrometer. The microplasma source provides sufficient energy to produce excited acetone fragments from the breath gas that emit light. The emitted light is sent to the spectrometer, which generates an emission spectrum that is used to detect and quantify acetone in the breath gas.

Robust optimization methods for cardiac sparing in tangential breast IMRT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahmoudzadeh, Houra, E-mail: houra@mie.utoronto.ca; Lee, Jenny; Chan, Timothy C. Y.

Purpose: In left-sided tangential breast intensity modulated radiation therapy (IMRT), the heart may enter the radiation field and receive excessive radiation while the patient is breathing. The patient’s breathing pattern is often irregular and unpredictable. We verify the clinical applicability of a heart-sparing robust optimization approach for breast IMRT. We compare robust optimized plans with clinical plans at free-breathing and clinical plans at deep inspiration breath-hold (DIBH) using active breathing control (ABC). Methods: Eight patients were included in the study with each patient simulated using 4D-CT. The 4D-CT image acquisition generated ten breathing phase datasets. An average scan was constructedmore » using all the phase datasets. Two of the eight patients were also imaged at breath-hold using ABC. The 4D-CT datasets were used to calculate the accumulated dose for robust optimized and clinical plans based on deformable registration. We generated a set of simulated breathing probability mass functions, which represent the fraction of time patients spend in different breathing phases. The robust optimization method was applied to each patient using a set of dose-influence matrices extracted from the 4D-CT data and a model of the breathing motion uncertainty. The goal of the optimization models was to minimize the dose to the heart while ensuring dose constraints on the target were achieved under breathing motion uncertainty. Results: Robust optimized plans were improved or equivalent to the clinical plans in terms of heart sparing for all patients studied. The robust method reduced the accumulated heart dose (D10cc) by up to 801 cGy compared to the clinical method while also improving the coverage of the accumulated whole breast target volume. On average, the robust method reduced the heart dose (D10cc) by 364 cGy and improved the optBreast dose (D99%) by 477 cGy. In addition, the robust method had smaller deviations from the planned dose to the accumulated dose. The deviation of the accumulated dose from the planned dose for the optBreast (D99%) was 12 cGy for robust versus 445 cGy for clinical. The deviation for the heart (D10cc) was 41 cGy for robust and 320 cGy for clinical. Conclusions: The robust optimization approach can reduce heart dose compared to the clinical method at free-breathing and can potentially reduce the need for breath-hold techniques.« less

Qualitative assessment of contrast-enhanced magnetic resonance angiography using breath-hold and non-breath-hold techniques in the portal venous system

NASA Astrophysics Data System (ADS)

Goo, Eun-Hoe; Kim, Sun-Ju; Dong, Kyung-Rae; Kim, Kwang-Choul; Chung, Woon-Kwan

2016-09-01

The purpose of this study is to evaluate the image quality in delineation of the portal venous systems with two different methods, breath-hold and non-breath-hold by using the 3D FLASH sequence. We used a 1.5 T system to obtain magnetic resonance(MR)images. Arterial and portal phase 3D FLASH images were obtained with breath-hold after a bolus injection of GD-DOTA. The detection of PVS on the MR angiograms was classified into three grades. First, the angiograms of the breath-hold method showed well the portal vein, the splenic vein and the superior mesenteric vein systems in 13 of 15 patients (86%) and the inferior mesenteric vein system in 6 of 15 patients (40%), Second, MR angiograms of the non-breath-hold method demonstrated the PVS and the SMV in 12 of 15 patients (80%) and the IMV in 5 of 15 patients (33%). Our study showed contrast-enhanced 3D FLASH MR angiography, together with the breath-hold technique, may provide reliable and accurate information on the portal venous system.

All APAPs Are Not Equivalent for the Treatment of Sleep Disordered Breathing: A Bench Evaluation of Eleven Commercially Available Devices.

PubMed

Zhu, Kaixian; Roisman, Gabriel; Aouf, Sami; Escourrou, Pierre

2015-07-15

This study challenged on a bench-test the efficacy of auto-titrating positive airway pressure (APAP) devices for obstructive sleep disordered breathing treatment and evaluated the accuracy of the device reports. Our bench consisted of an active lung simulator and a Starling resistor. Eleven commercially available APAP devices were evaluated on their reactions to single-type SDB sequences (obstructive apnea and hypopnea, central apnea, and snoring), and to a long general breathing scenario (5.75 h) simulating various SDB during four sleep cycles and to a short scenario (95 min) simulating one sleep cycle. In the single-type sequence of 30-minute repetitive obstructive apneas, only 5 devices normalized the airflow (> 70% of baseline breathing amplitude). Similarly, normalized breathing was recorded with 8 devices only for a 20-min obstructive hypopnea sequence. Five devices increased the pressure in response to snoring. Only 4 devices maintained a constant minimum pressure when subjected to repeated central apneas with an open upper airway. In the long general breathing scenario, the pressure responses and the treatment efficacy differed among devices: only 5 devices obtained a residual obstructive AHI < 5/h. During the short general breathing scenario, only 2 devices reached the same treatment efficacy (p < 0.001), and 3 devices underestimated the AHI by > 10% (p < 0.001). The long scenario led to more consistent device reports. Large differences between APAP devices in the treatment efficacy and the accuracy of report were evidenced in the current study. © 2015 American Academy of Sleep Medicine.

A randomised controlled trial of three or one breathing technique training sessions for breathlessness in people with malignant lung disease.

PubMed

Johnson, Miriam J; Kanaan, Mona; Richardson, Gerry; Nabb, Samantha; Torgerson, David; English, Anne; Barton, Rachael; Booth, Sara

2015-09-07

About 90 % of patients with intra-thoracic malignancy experience breathlessness. Breathing training is helpful, but it is unknown whether repeated sessions are needed. The present study aims to test whether three sessions are better than one for breathlessness in this population. This is a multi-centre randomised controlled non-blinded parallel arm trial. Participants were allocated to three sessions or single (1:2 ratio) using central computer-generated block randomisation by an independent Trials Unit and stratified for centre. The setting was respiratory, oncology or palliative care clinics at eight UK centres. Inclusion criteria were people with intrathoracic cancer and refractory breathlessness, expected prognosis ≥3 months, and no prior experience of breathing training. The trial intervention was a complex breathlessness intervention (breathing training, anxiety management, relaxation, pacing, and prioritisation) delivered over three hour-long sessions at weekly intervals, or during a single hour-long session. The main primary outcome was worst breathlessness over the previous 24 hours ('worst'), by numerical rating scale (0 = none; 10 = worst imaginable). Our primary analysis was area under the curve (AUC) 'worst' from baseline to 4 weeks. All analyses were by intention to treat. Between April 2011 and October 2013, 156 consenting participants were randomised (52 three; 104 single). Overall, the 'worst' score reduced from 6.81 (SD, 1.89) to 5.84 (2.39). Primary analysis [n = 124 (79 %)], showed no between-arm difference in the AUC: three sessions 22.86 (7.12) vs single session 22.58 (7.10); P value = 0.83); mean difference 0.2, 95 % CIs (-2.31 to 2.97). Complete case analysis showed a non-significant reduction in QALYs with three sessions (mean difference -0.006, 95 % CIs -0.018 to 0.006). Sensitivity analyses found similar results. The probability of the single session being cost-effective (threshold value of £20,000 per QALY) was over 80 %. There was no evidence that three sessions conferred additional benefits, including cost-effectiveness, over one. A single session of breathing training seems appropriate and minimises patient burden. Registry: ISRCTN; ISRCTN49387307; http://www.isrctn.com/ISRCTN49387307 ; registration date: 25/01/2011.

A dual mode breath sampler for the collection of the end-tidal and dead space fractions.

PubMed

Salvo, P; Ferrari, C; Persia, R; Ghimenti, S; Lomonaco, T; Bellagambi, F; Di Francesco, F

2015-06-01

This work presents a breath sampler prototype automatically collecting end-tidal (single and multiple breaths) or dead space air fractions (multiple breaths). This result is achieved by real time measurements of the CO2 partial pressure and airflow during the expiratory and inspiratory phases. Suitable algorithms, used to control a solenoid valve, guarantee that a Nalophan(®) bag is filled with the selected breath fraction even if the subject under test hyperventilates. The breath sampler has low pressure drop (<0.5 kPa) and uses inert or disposable components to avoid bacteriological risk for the patients and contamination of the breath samples. A fully customisable software interface allows a real time control of the hardware and software status. The performances of the breath sampler were evaluated by comparing (a) the CO2 partial pressure calculated during the sampling with the CO2 pressure measured off-line within the Nalophan(®) bag; (b) the concentrations of four selected volatile organic compounds in dead space, end-tidal and mixed breath fractions. Results showed negligible deviations between calculated and off-line CO2 pressure values and the distributions of the selected compounds into dead space, end-tidal and mixed breath fractions were in agreement with their chemical-physical properties. Copyright © 2015. Published by Elsevier Ltd.

TU-A-12A-02: Novel Lung Ventilation Imaging with Single Energy CT After Single Inhalation of Xenon: Comparison with SPECT Ventilation Images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Negahdar, M; Yamamoto, T; Shultz, D

Purpose: We propose a novel lung functional imaging method to determine the spatial distribution of xenon (Xe) gas in a single inhalation as a measure of regional ventilation. We compare Xe-CT ventilation to single-photon emission CT (SPECT) ventilation, which is the current clinical reference. Regional lung ventilation information may be useful for the diagnosis and monitoring of pulmonary diseases such as COPD, radiotherapy planning, and assessing the progression of toxicity after radiation therapy. Methods: In an IRB-approved clinical study, Xe-CT and SPECT ventilation scans were acquired for three patients including one patient with severe emphysema and two lung cancer patientsmore » treated with radiotherapy. For Xe- CT, we acquired two breath-hold single energy CT images of the entire lung with inspiration of 100% O2 and a mixture of 70% Xe and 30% O2, respectively. A video biofeedback system was used to achieve reproducible breath-holds. We used deformable image registration to align the breathhold images with each other to accurately subtract them, producing a map of the distribution of Xe as a surrogate of lung ventilation. We divided each lung into twelve parts and correlated the Hounsfield unit (HU) enhancement at each part with the SPECT ventilation count of the corresponding part of the lung. Results: The mean of the Pearson linear correlation coefficient values between the Xe-CT and ventilation SPECT count for all three patients were 0.62 (p<0.01). The Xe-CT image had a higher resolution than SPECT, and did not show central airway deposition artifacts that were present in the SPECT image. Conclusion: We developed a rapid, safe, clinically practical, and potentially widely accessible method for regional lung functional imaging. We demonstrated strong correlations between the Xe-CT ventilation image and SPECT ventilation image as the clinical reference. This ongoing study will investigate more patients to confirm this finding.« less

Continuous on-line measurements of respiratory system, lung and chest wall mechanics during mechanic ventilation.

PubMed

Kárason, S; Søndergaard, S; Lundin, S; Stenqvist, O

2001-08-01

We present a concept of on-line, manoeuvre-free monitoring of respiratory mechanics during dynamic conditions, displaying calculated alveolar pressure/volume curves continuously and separating lung and chest wall mechanics. Prospective observational study. Intensive care unit of a university hospital. Ten ventilator-treated patients with acute lung injury. Different positive end-expiratory pressure (PEEP) and tidal volumes, low flow inflation. Previously validated methods were used to present a single-value dynostatic compliance for the whole breath and a dynostatic volume-dependent initial, middle and final compliance within the breath. A high individual variation of respiratory mechanics was observed. Reproducibility of repeated measurements was satisfactory (coefficients of variations for dynostatic volume-dependent compliance: < or =9.2% for total respiratory system, < or =18% for lung). Volume-dependent compliance showed a statistically significant pattern of successively decreasing compliance from the initial segment through the middle and final parts within each breath at all respiratory settings. This pattern became more prominent with increasing PEEP and tidal volume, indicating a greater distension of alveoli. No lower inflection point (LIP) was seen in patients with respiratory rate 20/min and PEEP at 4 cmH2O. A trial with low flow inflation in four of the patients showed formation of a LIP in three of them and an upper inflection in one. The monitoring concept revealed a constant pattern of successively decreasing compliance within each breath, which became more prominent with increasing PEEP and tidal volume. The monitoring concept offers a simple and reliable method of monitoring respiratory mechanics during ongoing ventilator treatment.

Abdominal organ motion during inhalation and exhalation breath-holds: pancreatic motion at different lung volumes compared.

PubMed

Lens, Eelco; Gurney-Champion, Oliver J; Tekelenburg, Daniël R; van Kesteren, Zdenko; Parkes, Michael J; van Tienhoven, Geertjan; Nederveen, Aart J; van der Horst, Astrid; Bel, Arjan

2016-11-01

Contrary to what is commonly assumed, organs continue to move during breath-holding. We investigated the influence of lung volume on motion magnitude during breath-holding and changes in velocity over the duration of breath-holding. Sixteen healthy subjects performed 60-second inhalation breath-holds in room-air, with lung volumes of ∼100% and ∼70% of the inspiratory capacity, and exhalation breath-holds, with lung volumes of ∼30% and ∼0% of the inspiratory capacity. During breath-holding, we obtained dynamic single-slice magnetic-resonance images with a time-resolution of 0.6s. We used 2-dimensional image correlation to obtain the diaphragmatic and pancreatic velocity and displacement during breath-holding. Organ velocity was largest in the inferior-superior direction and was greatest during the first 10s of breath-holding, with diaphragm velocities of 0.41mm/s, 0.29mm/s, 0.16mm/s and 0.15mm/s during BH 100% , BH 70% , BH 30% and BH 0% , respectively. Organ motion magnitudes were larger during inhalation breath-holds (diaphragm moved 9.8 and 9.0mm during BH 100% and BH 70% , respectively) than during exhalation breath-holds (5.6 and 4.3mm during BH 30% and BH 0% , respectively). Using exhalation breath-holds rather than inhalation breath-holds and delaying irradiation until after the first 10s of breath-holding may be advantageous for irradiation of abdominal tumors. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Quantitative analysis of hepatic fat fraction by single-breath-holding MR spectroscopy with T₂ correction: phantom and clinical study with histologic assessment.

PubMed

Hayashi, Norio; Miyati, Tosiaki; Minami, Takashi; Takeshita, Yumie; Ryu, Yasuji; Matsuda, Tsuyoshi; Ohno, Naoki; Hamaguchi, Takashi; Kato, Kenichiro; Takamura, Toshinari; Matsui, Osamu

2013-01-01

The focus of this study was on the investigation of the accuracy of the fat fraction of the liver by use of single-breath-holding magnetic resonance spectroscopy (MRS) with T (2) correction. Single-voxel proton MRS was performed with several TE values, and the fat fraction was determined with and without T (2) correction. MRS was also performed with use of the point-resolved spectroscopy sequence in single breath holding. The T (2) values of both water and fat were determined separately at the same time, and the effect of T (2) on the fat fraction was corrected. In addition, MRS-based fat fractions were compared with the degree of hepatic steatosis (HS) by liver biopsy in human subjects. With T (2) correction, the MRI-derived fat fractions were in good agreement with the fat fractions in all phantoms, but the fat fractions were overestimated without T (2) correction. R (2) values were in good agreement with the preset iron concentrations in the phantoms. The MRI-derived fat fraction was well correlated with the degree of HS. Iron deposited in the liver affects the signal strength when proton MRS is used for detection of the fat signal in the liver. However, the fat signal can be evaluated more accurately when the T (2) correction is applied. Breath-holding MRS minimizes the respiratory motion, and it can be more accurate in the quantification of the hepatic fat fraction.

Free-breathing quantification of hepatic fat in healthy children and children with nonalcoholic fatty liver disease using a multi-echo 3-D stack-of-radial MRI technique.

PubMed

Armstrong, Tess; Ly, Karrie V; Murthy, Smruthi; Ghahremani, Shahnaz; Kim, Grace Hyun J; Calkins, Kara L; Wu, Holden H

2018-05-04

In adults, noninvasive chemical shift encoded Cartesian magnetic resonance imaging (MRI) and single-voxel magnetic resonance (MR) spectroscopy (SVS) accurately quantify hepatic steatosis but require breath-holding. In children, especially young and sick children, breath-holding is often limited or not feasible. Sedation can facilitate breath-holding but is highly undesirable. For these reasons, there is a need to develop free-breathing MRI technology that accurately quantifies steatosis in all children. This study aimed to compare non-sedated free-breathing multi-echo 3-D stack-of-radial (radial) MRI versus standard breath-holding MRI and SVS techniques in a group of children for fat quantification with respect to image quality, accuracy and repeatability. Healthy children (n=10, median age [±interquartile range]: 10.9 [±3.3] years) and overweight children with nonalcoholic fatty liver disease (NAFLD) (n=9, median age: 15.2 [±3.2] years) were imaged at 3 Tesla using free-breathing radial MRI, breath-holding Cartesian MRI and breath-holding SVS. Acquisitions were performed twice to assess repeatability (within-subject mean difference, MD within ). Images and hepatic proton-density fat fraction (PDFF) maps were scored for image quality. Free-breathing and breath-holding PDFF were compared using linear regression (correlation coefficient, r and concordance correlation coefficient, ρ c ) and Bland-Altman analysis (mean difference). P<0.05 was considered significant. In patients with NAFLD, free-breathing radial MRI demonstrated significantly less motion artifacts compared to breath-holding Cartesian (P<0.05). Free-breathing radial PDFF demonstrated a linear relationship (P<0.001) versus breath-holding SVS PDFF and breath-holding Cartesian PDFF with r=0.996 and ρ c =0.994, and r=0.997 and ρ c =0.995, respectively. The mean difference in PDFF between free-breathing radial MRI, breath-holding Cartesian MRI and breath-holding SVS was <0.7%. Repeated free-breathing radial MRI had MD within =0.25% for PDFF. In this pediatric study, non-sedated free-breathing radial MRI provided accurate and repeatable hepatic PDFF measurements and improved image quality, compared to standard breath-holding MR techniques.

The Short-Term Effect of Breathing Tasks Via an Incentive Spirometer on Lung Function Compared With Autogenic Drainage in Subjects With Cystic Fibrosis.

PubMed

Sokol, Gil; Vilozni, Daphna; Hakimi, Ran; Lavie, Moran; Sarouk, Ifat; Bat-El Bar; Dagan, Adi; Ofek, Miryam; Efrati, Ori

2015-12-01

Forced expiration may assist secretion movement by manipulating airway dynamics in patients with cystic fibrosis (CF). Expiratory resistive breathing via a handheld incentive spirometer has the potential to control the expiratory flow via chosen resistances (1-8 mm) and thereby mobilize secretions and improve lung function. Our objective was to explore the short-term effect of using a resistive-breathing incentive spirometer on lung function in subjects with CF compared with the autogenic drainage technique. This was a retrospective study. Subjects with CF performed 30-45 min of either the resistive-breathing incentive spirometer (n = 40) or autogenic drainage (n = 32) technique on separate days. The spirometer encourages the patient to exhale as long as possible while maintaining a low lung volume. The autogenic drainage technique includes repetitive inspiratory and expiratory maneuvers at various tidal breathing magnitudes while exhalation is performed in a sighing manner. Spirometry was performed before and 20-30 min after the therapy. Use of a resistive-breathing incentive spirometer improved FVC and FEV1 by 5-42% in 26 subjects. The forced expiratory flow during the middle half of the FVC maneuver (FEF25-75%) improved by >20% in 9 (22%) subjects. FVC improved the most in subjects with an FEV1 of 40-60% of predicted. Improvements negatively correlated with baseline percent-of-predicted FVC values provided improvements were above 10% (r(2) = 0.28). Values improved in a single subjects using the autogenic drainage technique. These 2 techniques may allow lower thoracic pressures and assist in the prevention of central airway collapse. The resistive-breathing incentive spirometer is a self-administered simple method that may aid airway clearance and has the potential to improve lung function as measured by FVC, FEV1, and FEF25-75% in patients with CF. Copyright © 2015 by Daedalus Enterprises.

Inter- and intraobserver agreement of ADC measurements of lung cancer in free breathing, breath-hold and respiratory triggered diffusion-weighted MRI.

PubMed

Cui, Lei; Yin, Jian-Bing; Hu, Chun-Hong; Gong, Shen-Chu; Xu, Jun-Feng; Yang, Ju-Shun

2016-01-01

To prospectively evaluate the inter- and intraobserver agreement of apparent diffusion coefficient (ADC) measurements in free breathing, breath-hold, and respiratory triggered diffusion-weighted imaging (DWI) of lung cancer. Twenty-two patients with lung cancer (tumor size >2cm) underwent DWIs (3.0T) in three imaging methods. Lesion ADCs were measured twice by both of the two independent observers and compared. No statistical significance was found among methods, though respiratory-triggered DWI tended to have higher ADCs than breath-hold DWI. Great inter- and intraobserver agreement was shown. ADCs had good inter- and intraobserver agreement in all three DWI methods. Copyright © 2016 Elsevier Inc. All rights reserved.

Epiglottitis

MedlinePlus

... used. This examination is best done in the operating room or a similar setting where sudden breathing problems ... (ICU). Treatment involves methods to help the person breathe, including: Breathing tube ( ...

SU-E-J-67: Evaluation of Breathing Patterns for Respiratory-Gated Radiation Therapy Using Respiration Regularity Index

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheong, K; Lee, M; Kang, S

2014-06-01

Purpose: Despite the importance of accurately estimating the respiration regularity of a patient in motion compensation treatment, an effective and simply applicable method has rarely been reported. The authors propose a simple respiration regularity index based on parameters derived from a correspondingly simplified respiration model. Methods: In order to simplify a patient's breathing pattern while preserving the data's intrinsic properties, we defined a respiration model as a power of cosine form with a baseline drift. According to this respiration formula, breathing-pattern fluctuation could be explained using four factors: sample standard deviation of respiration period, sample standard deviation of amplitude andmore » the results of simple regression of the baseline drift (slope and standard deviation of residuals of a respiration signal. Overall irregularity (δ) was defined as a Euclidean norm of newly derived variable using principal component analysis (PCA) for the four fluctuation parameters. Finally, the proposed respiration regularity index was defined as ρ=ln(1+(1/ δ))/2, a higher ρ indicating a more regular breathing pattern. Subsequently, we applied it to simulated and clinical respiration signals from real-time position management (RPM; Varian Medical Systems, Palo Alto, CA) and investigated respiration regularity. Moreover, correlations between the regularity of the first session and the remaining fractions were investigated using Pearson's correlation coefficient. Results: The respiration regularity was determined based on ρ; patients with ρ<0.3 showed worse regularity than the others, whereas ρ>0.7 was suitable for respiratory-gated radiation therapy (RGRT). Fluctuations in breathing cycle and amplitude were especially determinative of ρ. If the respiration regularity of a patient's first session was known, it could be estimated through subsequent sessions. Conclusions: Respiration regularity could be objectively determined using a respiration regularity index, ρ. Such single-index testing of respiration regularity can facilitate determination of RGRT availability in clinical settings, especially for free-breathing cases. This work was supported by a Korea Science and Engineering Foundation (KOSEF) grant funded by the Korean Ministry of Science, ICT and Future Planning (No. 2013043498)« less

Assessing the severity of sleep apnea syndrome based on ballistocardiogram

PubMed Central

Zhou, Xingshe; Zhao, Weichao; Liu, Fan; Ni, Hongbo; Yu, Zhiwen

2017-01-01

Background Sleep Apnea Syndrome (SAS) is a common sleep-related breathing disorder, which affects about 4-7% males and 2-4% females all around the world. Different approaches have been adopted to diagnose SAS and measure its severity, including the gold standard Polysomnography (PSG) in sleep study field as well as several alternative techniques such as single-channel ECG, pulse oximeter and so on. However, many shortcomings still limit their generalization in home environment. In this study, we aim to propose an efficient approach to automatically assess the severity of sleep apnea syndrome based on the ballistocardiogram (BCG) signal, which is non-intrusive and suitable for in home environment. Methods We develop an unobtrusive sleep monitoring system to capture the BCG signals, based on which we put forward a three-stage sleep apnea syndrome severity assessment framework, i.e., data preprocessing, sleep-related breathing events (SBEs) detection, and sleep apnea syndrome severity evaluation. First, in the data preprocessing stage, to overcome the limits of BCG signals (e.g., low precision and reliability), we utilize wavelet decomposition to obtain the outline information of heartbeats, and apply a RR correction algorithm to handle missing or spurious RR intervals. Afterwards, in the event detection stage, we propose an automatic sleep-related breathing event detection algorithm named Physio_ICSS based on the iterative cumulative sums of squares (i.e., the ICSS algorithm), which is originally used to detect structural breakpoints in a time series. In particular, to efficiently detect sleep-related breathing events in the obtained time series of RR intervals, the proposed algorithm not only explores the practical factors of sleep-related breathing events (e.g., the limit of lasting duration and possible occurrence sleep stages) but also overcomes the event segmentation issue (e.g., equal-length segmentation method might divide one sleep-related breathing event into different fragments and lead to incorrect results) of existing approaches. Finally, by fusing features extracted from multiple domains, we can identify sleep-related breathing events and assess the severity level of sleep apnea syndrome effectively. Conclusions Experimental results on 136 individuals of different sleep apnea syndrome severities validate the effectiveness of the proposed framework, with the accuracy of 94.12% (128/136). PMID:28445548

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chow, Kam Kong; Zeng, Haishan, E-mail: hzeng@bccrc.ca; Short, Michael

Purpose: Breath analysis has a potential prospect to benefit the medical field based on its perceived advantages to become a point-of-care, easy to use, and cost-effective technology. Early studies done by mass spectrometry show that volatile organic compounds from human breath can represent certain disease states of our bodies, such as lung cancer, and revealed the potential of breath analysis. But mass spectrometry is costly and has slow-turnaround time. The authors’ goal is to develop a more portable and cost effective device based on Raman spectroscopy and hollow core-photonic crystal fiber (HC-PCF) for breath analysis. Methods: Raman scattering is amore » photon-molecular interaction based on the kinetic modes of an analyte which offers unique fingerprint type signals that allow molecular identification. HC-PCF is a novel light guide which allows light to be confined in a hollow core and it can be filled with a gaseous sample. Raman signals generated by the gaseous sample (i.e., human breath) can be guided and collected effectively for spectral analysis. Results: A Raman-cell based on HC-PCF in the near infrared wavelength range was developed and tested in a single pass forward-scattering mode for different gaseous samples. Raman spectra were obtained successfully from reference gases (hydrogen, oxygen, carbon dioxide gases), ambient air, and a human breath sample. The calculated minimum detectable concentration of this system was ∼15 parts per million by volume, determined by measuring the carbon dioxide concentration in ambient air via the characteristic Raman peaks at 1286 and 1388 cm{sup −1}. Conclusions: The results of this study were compared to a previous study using HC-PCF to trap industrial gases and backward-scatter 514.5 nm light from them. The authors found that the method presented in this paper has an advantage to enhance the signal-to-noise ratio (SNR). This SNR advantage, coupled with the better transmission of HC-PCF in the near-IR than in the visible wavelengths led to an estimated seven times improvement in the detection sensitivity. The authors’ prototype device also demonstrated a 100-fold improvement over a recently reported detection limit of a reflective capillary fiber-based Raman cell for breath analysis. Continued development is underway to increase the detection sensitivity further to reach practical clinical applications.« less

The rise in carboxyhemoglobin from repeated pulmonary diffusing capacity tests.

PubMed

Zavorsky, Gerald S

2013-03-01

The purpose of this study determined the rise in carboxyhemoglobin percentage (COHb) from repeated pulmonary diffusing capacity tests using 5 or 10s single breath-hold maneuvers. Five male and four female non-smokers [baseline COHb=1.2 (SD 0.5%)] performed repeated pulmonary diffusing capacity testing on two separate days. The days were randomized to either repeated 10s (0.28% CO), or 5s (0.28% CO, 55ppm NO) breath-hold maneuvers. Twenty-two 5s breath-hold maneuvers, each separated by 4min rest, raised COHb to 11.1 (1.4)% and minimally raised the methemoglobin percentage (METHb) by 0.3 (0.2)% to a value of 0.8 (0.2)%. After the 22nd test, pulmonary diffusing capacity for carbon monoxide (DLCO) was reduced by about 4mL/min/mmHg, equating to a 0.44% increase in COHb per 5s breath-hold maneuver and a concomitant 0.35mL/min/mmHg decrease in DLCO. Pulmonary diffusing capacity for nitric oxide (DLNO) was not altered after 22 tests. On another day, the 10s single breath-hold maneuver increased COHb by 0.64% per test, and reduced DLCO by 0.44mL/min/mmHg per test. In conclusion, 5s breath-hold maneuvers do not appreciably raise METHb or DLNO, and DLCO is only significantly reduced when COHb is at least 6%. Copyright © 2013 Elsevier B.V. All rights reserved.

MO-FG-BRA-02: A Feasibility Study of Integrating Breathing Audio Signal with Surface Surrogates for Respiratory Motion Management

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lei, Y; Zhu, X; Zheng, D

Purpose: Tracking the surrogate placed on patient skin surface sometimes leads to problematic signals for certain patients, such as shallow breathers. This in turn impairs the 4D CT image quality and dosimetric accuracy. In this pilot study, we explored the feasibility of monitoring human breathing motion by integrating breathing sound signal with surface surrogates. Methods: The breathing sound signals were acquired though a microphone attached adjacently to volunteer’s nostrils, and breathing curve were analyzed using a low pass filter. Simultaneously, the Real-time Position Management™ (RPM) system from Varian were employed on a volunteer to monitor respiratory motion including both shallowmore » and deep breath modes. The similar experiment was performed by using Calypso system, and three beacons taped on volunteer abdominal region to capture breath motion. The period of each breathing curves were calculated with autocorrelation functions. The coherence and consistency between breathing signals using different acquisition methods were examined. Results: Clear breathing patterns were revealed by the sound signal which was coherent with the signal obtained from both the RPM system and Calypso system. For shallow breathing, the periods of breathing cycle were 3.00±0.19 sec (sound) and 3.00±0.21 sec (RPM); For deep breathing, the periods were 3.49± 0.11 sec (sound) and 3.49±0.12 sec (RPM). Compared with 4.54±0.66 sec period recorded by the calypso system, the sound measured 4.64±0.54 sec. The additional signal from sound could be supplement to the surface monitoring, and provide new parameters to model the hysteresis lung motion. Conclusion: Our preliminary study shows that the breathing sound signal can provide a comparable way as the RPM system to evaluate the respiratory motion. It’s instantaneous and robust characteristics facilitate it possibly to be a either independently or as auxiliary methods to manage respiratory motion in radiotherapy.« less

Comparison of the heart and breathing rate of acutely ill medical patients recorded by nursing staff with those measured over 5 min by a piezoelectric belt and ECG monitor at the time of admission to hospital.

PubMed

Kellett, John; Li, Min; Rasool, Shahzeb; Green, Geoffrey C; Seely, Andrew

2011-11-01

Heart and breathing rates are predictors of disease severity and of a poor outcome. However, few reports have compared their machine measurements with traditional manual methods. A small rural Irish hospital. The heart and breathing rates of 377 acutely ill medical patients (mean age 68.3 SD 16.8 years) recorded by nursing staff at the time of admission to hospital was compared with those measured over 5 min by a piezoelectric belt and ECG monitor (the BT16 acquisition system). The mean breathing rate measured by the nursing staff (20.9 SD 4.8 breaths per min) and that measured by the BT16 piezoelectric belt (19.9 SD 4.5 breaths per min) were significantly different (p 0.004), as were the nurse and BT16 measured heart rates (85.4 SD 21.3 vs. 81.2 SD 18.7, p 0.004), and the correlation coefficient between the two methods of breathing and heart rate measurement were low. Nurse measured breathing rate measurements were clustered around rates of 18, 20 and 22 breaths per min. Unlike those obtained by nurses, BT16 measured heart and breathing rates were shown by logistic regression to be independent predictors of in-hospital mortality. There is a poor correlation between breathing and heart rates measured by traditional methods and those obtained by the BT16 device. BT16 derived breathing and heart rates, but not those measured manually, were independent predictors of in-hospital mortality. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Personal exposure to JP-8 jet fuel vapors and exhaust at air force bases.

PubMed

Pleil, J D; Smith, L B; Zelnick, S D

2000-03-01

JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and ground crew personnel during preflight operations and for maintenance personnel performing routine tasks. Personal exposure at an Air Force base occurs through occupational exposure for personnel involved with fuel and aircraft handling and/or through incidental exposure, primarily through inhalation of ambient fuel vapors. Because JP-8 is less volatile than its predecessor fuel (JP-4), contact with liquid fuel on skin and clothing may result in prolonged exposure. The slowly evaporating JP-8 fuel tends to linger on exposed personnel during their interaction with their previously unexposed colleagues. To begin to assess the relative exposures, we made ambient air measurements and used recently developed methods for collecting exhaled breath in special containers. We then analyzed for certain volatile marker compounds for JP-8, as well as for some aromatic hydrocarbons (especially benzene) that are related to long-term health risks. Ambient samples were collected by using compact, battery-operated, personal whole-air samplers that have recently been developed as commercial products; breath samples were collected using our single-breath canister method that uses 1-L canisters fitted with valves and small disposable breathing tubes. We collected breath samples from various groups of Air Force personnel and found a demonstrable JP-8 exposure for all subjects, ranging from slight elevations as compared to a control cohort to > 100 [mutilpe] the control values. This work suggests that further studies should be performed on specific issues to obtain pertinent exposure data. The data can be applied to assessments of health outcomes and to recommendations for changes in the use of personal protective equipment that optimize risk reduction without undue impact on a mission.

SU-E-J-223: A BOLD Contrast Imaging Sequence to Evaluate Oxygenation Changes Due to Breath Holding for Breast Radiotherapy: A Pilot Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamson, J; Chang, Z; Cai, J

Purpose: To develop a robust MRI sequence to measure BOLD breath hold induced contrast in context of breast radiotherapy. Methods: Two sequences were selected from prior studies as candidates to measure BOLD contrast attributable to breath holding within the breast: (1) T2* based Gradient Echo EPI (TR/TE = 500/41ms, flip angle = 60°), and (2) T2 based Single Shot Fast Spin Echo (SSFSE) (TR/TE = 3000/60ms). We enrolled ten women post-lumpectomy for breast cancer who were undergoing treatment planning for whole breast radiotherapy. Each session utilized a 1.5T GE MRI and 4 channel breast coil with the subject immobilized pronemore » on a custom board. For each sequence, 1–3 planes of the lumpectomy breast were imaged continuously during a background measurement (1min) and intermittent breath holds (20–40s per breath hold, 3–5 holds per sequence). BOLD contrast was quantified as correlation of changes in per-pixel intensity with the breath hold schedule convolved with a hemodynamic response function. Subtle motion was corrected using a deformable registration algorithm. Correlation with breath-holding was considered significant if p<0.001. Results: The percentage of the breast ROI with positive BOLD contrast measured by the two sequences were in agreement with a correlation coefficient of R=0.72 (p=0.02). While both sequences demonstrated areas with strong BOLD response, the response was more systematic throughout the breast for the SSFSE (T2) sequence (% breast with response in the same direction: 51.2%±0.7% for T2* vs. 68.1%±16% for T2). In addition, the T2 sequence was less prone to magnetic susceptibility artifacts, especially in presence of seroma, and provided a more robust image with little distortion or artifacts. Conclusion: A T2 SSFSE sequence shows promise for measuring BOLD contrast in the context of breast radiotherapy utilizing a breath hold technique. Further study in a larger patient cohort is warranted to better refine this novel technique.« less

Detection of gaseous compounds by needle trap sampling and direct thermal-desorption photoionization mass spectrometry: concept and demonstrative application to breath gas analysis.

PubMed

Kleeblatt, Juliane; Schubert, Jochen K; Zimmermann, Ralf

2015-02-03

A fast detection method to analyze gaseous organic compounds in complex gas mixtures was developed, using a needle trap device (NTD) in conjunction with thermal-desorption photoionization time-of-flight mass spectrometry (TD-PI-TOFMS). The mass spectrometer was coupled via a deactivated fused silica capillary to an injector of a gas chromatograph. In the hot injector, the analytes collected on the NTD were thermally desorbed and directly transferred to the PI-TOFMS ion source. The molecules are softly ionized either by single photon ionization (SPI, 118 nm) or by resonance enhanced multiphoton ionization (REMPI, 266 nm), and the molecular ion signals are detected in the TOF mass analyzer. Analyte desorption and the subsequent PI-TOFMS detection step only lasts ten seconds. The specific selectivity of REMPI (i.e., aromatic compounds) and universal ionization characteristics render PI-MS as a promising detection system. As a first demonstrative application, the alveolar phase breath gas of healthy, nonsmoking subjects was sampled on NTDs. While smaller organic compounds such as acetone, acetaldehyde, isoprene, or cysteamine can be detected in the breath gas with SPI, REMPI depicts the aromatic substances phenol and indole at 266 nm. In the breath gas of a healthy, smoking male subject, several xenobiotic substances such as benzene, toluene, styrene, and ethylbenzene can be found as well. Furthermore, the NTD-REMPI-TOFMS setup was tested for breath gas taken from a mechanically ventilated pig under continuous intravenous propofol (2,6-diisopropylphenol, narcotic drug) infusion.

New method to calculate the N2 evolution from mixed venous blood during the N2 washout.

PubMed

Han, D; Jeng, D R; Cruz, J C; Flores, X F; Mallea, J M

2001-08-01

To model the normalized phase III slope (Sn) from N2 expirograms of the multibreath N2 washout is a challenge to researchers. Experimental measurements show that Sn increases with the number of breaths. Previously, we predicted Sn by setting the concentration (atm) of mixed venous blood (Fbi,N2) to a constant value of 0.3 after the fifth breath to calculate the amount of N2 transferred from the blood to the alveoli. As a consequence, the predicted curve of the Sn values showed a maximum before the quasi-steady state was reached. In this paper, we present a way of calculating the amount of N2 transferred from the blood to the alveoli by setting Fbi,N2 in the following way: In the first six breaths Fbi,N2 is kept constant at the initial value of 0.8 because circulation time needs at least 30 s to alter it. Thereafter, a single exponential function with respect the number of breaths is used: Fbi = 0.8 exp[0.112(6-n)], in which n is the breath number. The predicted Sn values were compared with experimental data from the literature. The assumption of an exponential decay in the N2 evolved from mixed venous blood is important in determining the shape of the Sn curve but new experimental data are needed to determine the validity of the model. We concluded that this new approach to calculate the N2 evolution from the blood is more meaningful physiologically.

Matter over mind: a randomised-controlled trial of single-session biofeedback training on performance anxiety and heart rate variability in musicians.

PubMed

Wells, Ruth; Outhred, Tim; Heathers, James A J; Quintana, Daniel S; Kemp, Andrew H

2012-01-01

Musical performance is a skilled activity performed under intense pressure, thus is often a profound source of anxiety. In other contexts, anxiety and its concomitant symptoms of sympathetic nervous system arousal have been successfully ameliorated with HRV biofeedback (HRV BF), a technique involving slow breathing which augments autonomic and emotional regulatory capacity. This randomised-controlled study explored the impact of a single 30-minute session of HRV BF on anxiety in response to a highly stressful music performance. A total of 46 trained musicians participated in this study and were randomly allocated to a slow breathing with or without biofeedback or no-treatment control group. A 3 Group×2 Time mixed experimental design was employed to compare the effect of group before and after intervention on performance anxiety (STAI-S) and frequency domain measures of HRV. Slow breathing groups (n=30) showed significantly greater improvements in high frequency (HF) and LF/HF ratio measures of HRV relative to control (n=15) during 5 minute recordings of performance anticipation following the intervention (effect size: η(2) =0.122 and η(2) =0.116, respectively). The addition of biofeedback to a slow breathing protocol did not produce differential results. While intervention groups did not exhibit an overall reduction in self-reported anxiety, participants with high baseline anxiety who received the intervention (n=15) displayed greater reductions in self-reported state anxiety relative to those in the control condition (n=7) (r=0.379). These findings indicate that a single session of slow breathing, regardless of biofeedback, is sufficient for controlling physiological arousal in anticipation of psychosocial stress associated with music performance and that slow breathing is particularly helpful for musicians with high levels of anxiety. Future research is needed to further examine the effects of HRV BF as a low-cost, non-pharmacological treatment for music performance anxiety.

The Wagner-Nelson method can generate an accurate gastric emptying flow curve from CO2 data obtained by a 13C-labeled substrate breath test.

PubMed

Sanaka, Masaki; Yamamoto, Takatsugu; Ishii, Tarou; Kuyama, Yasushi

2004-01-01

In pharmacokinetics, the Wagner-Nelson (W-N) method can accurately estimate the rate of drug absorption from its urinary elimination rate. A stable isotope (13C) breath test attempts to estimate the rate of absorption of 13C, as an index of gastric emptying rate, from the rate of pulmonary elimination of 13CO2. The time-gastric emptying curve determined by the breath test is quite different from that determined by scintigraphy or ultrasonography. In this report, we have shown that the W-N method can adjust the difference. The W-N equation to estimate gastric emptying from breath data is as follows: the fractional cumulative amount of gastric contents emptied by time t = Abreath (t)/Abreath (infinity) + (1/0.65).d[Abreath (t)/Abreath (infinity) ]/dt, where Abreath (t) = the cumulative recovery of 13CO2 in breath by time t and Abreath ( infinity ) = the ultimate cumulative 13CO2 recovery. The emptying flow curve generated by ultrasonography was compared with that generated by the W-N method-adjusted breath test in 6 volunteers. The emptying curves by the W-N method were almost identical to those by ultrasound. The W-N method can generate an accurate emptying flow curve from 13CO2 data, and it can adjust the difference between ultrasonography and the breath test. Copyright 2004 S. Karger AG, Basel

Multiview 3-D Echocardiography Fusion with Breath-Hold Position Tracking Using an Optical Tracking System.

PubMed

Punithakumar, Kumaradevan; Hareendranathan, Abhilash R; McNulty, Alexander; Biamonte, Marina; He, Allen; Noga, Michelle; Boulanger, Pierre; Becher, Harald

2016-08-01

Recent advances in echocardiography allow real-time 3-D dynamic image acquisition of the heart. However, one of the major limitations of 3-D echocardiography is the limited field of view, which results in an acquisition insufficient to cover the whole geometry of the heart. This study proposes the novel approach of fusing multiple 3-D echocardiography images using an optical tracking system that incorporates breath-hold position tracking to infer that the heart remains at the same position during different acquisitions. In six healthy male volunteers, 18 pairs of apical/parasternal 3-D ultrasound data sets were acquired during a single breath-hold as well as in subsequent breath-holds. The proposed method yielded a field of view improvement of 35.4 ± 12.5%. To improve the quality of the fused image, a wavelet-based fusion algorithm was developed that computes pixelwise likelihood values for overlapping voxels from multiple image views. The proposed wavelet-based fusion approach yielded significant improvement in contrast (66.46 ± 21.68%), contrast-to-noise ratio (49.92 ± 28.71%), signal-to-noise ratio (57.59 ± 47.85%) and feature count (13.06 ± 7.44%) in comparison to individual views. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Raman spectroscopy: Watching a molecule breathe

NASA Astrophysics Data System (ADS)

Piatkowski, Lukasz; Hugall, James T.; van Hulst, Niek F.

2014-08-01

Marrying the single-molecule detection ability of surface-enhanced Raman scattering with the extreme time resolution of ultrafast coherent spectroscopy enables the vibrations of a single molecule to be observed.

Application of cabin atmosphere monitors to rapid screening of breath samples for the early detection of disease states

NASA Technical Reports Server (NTRS)

Valentine, J. L.; Bryant, P. J.

1975-01-01

Analysis of human breath is a nonintrusive method to monitor both endogenous and exogenous chemicals found in the body. Several technologies were investigated and developed which are applicable to monitoring some organic molecules important in both physiological and pathological states. Two methods were developed for enriching the organic molecules exhaled in the breath of humans. One device is based on a respiratory face mask fitted with a polyethylene foam wafer; while the other device is a cryogenic trap utilizing an organic solvent. Using laboratory workers as controls, two organic molecules which occurred in the enriched breath of all subjects were tentatively identified as lactic acid and contisol. Both of these substances occurred in breath in sufficient amounts that the conventional method of gas-liquid chromatography was adequate for detection and quantification. To detect and quantitate trace amounts of chemicals in breath, another type of technology was developed in which analysis was conducted using high pressure liquid chromatography and mass spectrometry.

Breath Figure Method for Construction of Honeycomb Films

PubMed Central

Dou, Yingying; Jin, Mingliang; Zhou, Guofu; Shui, Lingling

2015-01-01

Honeycomb films with various building units, showing potential applications in biological, medical, physicochemical, photoelectric, and many other areas, could be prepared by the breath figure method. The ordered hexagonal structures formed by the breath figure process are related to the building units, solvents, substrates, temperature, humidity, air flow, and other factors. Therefore, by adjusting these factors, the honeycomb structures could be tuned properly. In this review, we summarized the development of the breath figure method of fabricating honeycomb films and the factors of adjusting honeycomb structures. The organic-inorganic hybrid was taken as the example building unit to discuss the preparation, mechanism, properties, and applications of the honeycomb films. PMID:26343734

Decompression sickness in breath-hold diving, and its probable connection to the growth and dissolution of small arterial gas emboli.

PubMed

Goldman, Saul; Solano-Altamirano, J M

2015-04-01

We solved the Laplace equation for the radius of an arterial gas embolism (AGE), during and after breath-hold diving. We used a simple three-region diffusion model for the AGE, and applied our results to two types of breath-hold dives: single, very deep competitive-level dives and repetitive shallower breath-hold dives similar to those carried out by indigenous commercial pearl divers in the South Pacific. Because of the effect of surface tension, AGEs tend to dissolve in arterial blood when arteries remote from supersaturated tissue. However if, before fully dissolving, they reach the capillary beds that perfuse the brain and the inner ear, they may become inflated with inert gas that is transferred into them from these contiguous temporarily supersaturated tissues. By using simple kinetic models of cerebral and inner ear tissue, the nitrogen tissue partial pressures during and after the dive(s) were determined. These were used to theoretically calculate AGE growth and dissolution curves for AGEs lodged in capillaries of the brain and inner ear. From these curves it was found that both cerebral and inner ear decompression sickness are expected to occur occasionally in single competitive-level dives. It was also determined from these curves that for the commercial repetitive dives considered, the duration of the surface interval (the time interval separating individual repetitive dives from one another) was a key determinant, as to whether inner ear and/or cerebral decompression sickness arose. Our predictions both for single competitive-level and repetitive commercial breath-hold diving were consistent with what is known about the incidence of cerebral and inner ear decompression sickness in these forms of diving. Copyright © 2015 Elsevier Inc. All rights reserved.

Two dimensional microcirculation mapping with real time spatial frequency domain imaging

NASA Astrophysics Data System (ADS)

Zheng, Yang; Chen, Xinlin; Lin, Weihao; Cao, Zili; Zhu, Xiuwei; Zeng, Bixin; Xu, M.

2018-02-01

We present a spatial frequency domain imaging (SFDI) study of local hemodynamics in the human finger cuticle of healthy volunteers performing paced breathing and the forearm of healthy young adults performing normal breathing with our recently developed Real Time Single Snapshot Multiple Frequency Demodulation - Spatial Frequency Domain Imaging (SSMD-SFDI) system. A two-layer model was used to map the concentrations of deoxy-, oxy-hemoglobin, melanin, epidermal thickness and scattering properties at the subsurface of the forearm and the finger cuticle. The oscillations of the concentrations of deoxy- and oxy-hemoglobin at the subsurface of the finger cuticle and forearm induced by paced breathing and normal breathing, respectively, were found to be close to out-of-phase, attributed to the dominance of the blood flow modulation by paced breathing or heartbeat. Our results suggest that the real time SFDI platform may serve as one effective imaging modality for microcirculation monitoring.

Technologies for Clinical Diagnosis Using Expired Human Breath Analysis

PubMed Central

Mathew, Thalakkotur Lazar; Pownraj, Prabhahari; Abdulla, Sukhananazerin; Pullithadathil, Biji

2015-01-01

This review elucidates the technologies in the field of exhaled breath analysis. Exhaled breath gas analysis offers an inexpensive, noninvasive and rapid method for detecting a large number of compounds under various conditions for health and disease states. There are various techniques to analyze some exhaled breath gases, including spectrometry, gas chromatography and spectroscopy. This review places emphasis on some of the critical biomarkers present in exhaled human breath, and its related effects. Additionally, various medical monitoring techniques used for breath analysis have been discussed. It also includes the current scenario of breath analysis with nanotechnology-oriented techniques. PMID:26854142

Can simple mobile phone applications provide reliable counts of respiratory rates in sick infants and children? An initial evaluation of three new applications.

PubMed

Black, James; Gerdtz, Marie; Nicholson, Pat; Crellin, Dianne; Browning, Laura; Simpson, Julie; Bell, Lauren; Santamaria, Nick

2015-05-01

Respiratory rate is an important sign that is commonly either not recorded or recorded incorrectly. Mobile phone ownership is increasing even in resource-poor settings. Phone applications may improve the accuracy and ease of counting of respiratory rates. The study assessed the reliability and initial users' impressions of four mobile phone respiratory timer approaches, compared to a 60-second count by the same participants. Three mobile applications (applying four different counting approaches plus a standard 60-second count) were created using the Java Mobile Edition and tested on Nokia C1-01 phones. Apart from the 60-second timer application, the others included a counter based on the time for ten breaths, and three based on the time interval between breaths ('Once-per-Breath', in which the user presses for each breath and the application calculates the rate after 10 or 20 breaths, or after 60s). Nursing and physiotherapy students used the applications to count respiratory rates in a set of brief video recordings of children with different respiratory illnesses. Limits of agreement (compared to the same participant's standard 60-second count), intra-class correlation coefficients and standard errors of measurement were calculated to compare the reliability of the four approaches, and a usability questionnaire was completed by the participants. There was considerable variation in the counts, with large components of the variation related to the participants and the videos, as well as the methods. None of the methods was entirely reliable, with no limits of agreement better than -10 to +9 breaths/min. Some of the methods were superior to the others, with ICCs from 0.24 to 0.92. By ICC the Once-per-Breath 60-second count and the Once-per-Breath 20-breath count were the most consistent, better even than the 60-second count by the participants. The 10-breath approaches performed least well. Users' initial impressions were positive, with little difference between the applications found. This study provides evidence that applications running on simple phones can be used to count respiratory rates in children. The Once-per-Breath methods are the most reliable, outperforming the 60-second count. For children with raised respiratory rates the 20-breath version of the Once-per-Breath method is faster, so it is a more suitable option where health workers are under time pressure. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cross-cultural comparison of the sleep-disordered breathing prevalence among Americans and Japanese

PubMed Central

Yamagishi, Kazumasa; Ohira, Tetsuya; Nakano, Hiroshi; Bielinski, Suzette J.; Sakurai, Susumu; Imano, Hironori; Kiyama, Masahiko; Kitamura, Akihiko; Sato, Shinichi; Konishi, Masamitsu; Shahar, Eyal; Folsom, Aaron R.; Iso, Hiroyasu; Tanigawa, Takeshi

2010-01-01

To compare the sleep-disordered breathing prevalence among Hispanic and white Americans and Japanese, we performed a one-night sleep study with a single channel airflow monitor on 211 Hispanics and 246 whites from the Minnesota Field Center of the Multi-Ethnic Study of Atherosclerosis (MESA), and 978 Japanese from three community-based cohorts of the Circulatory Risk in Communities Study (CIRCS) in Japan. The respiratory disturbance index and sleep-disordered breathing, defined as respiratory disturbance index ≥ 15 disturbances/hr, were estimated. The sleep-disordered breathing prevalence was higher in men (34.2%) than women (14.8%), and higher among Hispanics (36.5%) and whites (33.3%) than among Japanese (18.4%), corresponding to differences in body mass index. Within body mass index strata, the race difference in sleep-disordered breathing was attenuated. This was also true when we adjusted for body mass index instead of stratification. The strong association between body mass index and sleep-disordered breathing was similar in Japanese and Americans. The sleep-disordered breathing prevalence was lower among Japanese than the Americans. However, the association of body mass index with sleep-disordered breathing was strong, and similar among the race/ethnic groups studied. The majority of the race/ethnic difference in sleep-disordered breathing prevalence was explained by a difference in body mass index distribution. PMID:20110399

Patients' experiences of breathing retraining for asthma: a qualitative process analysis of participants in the intervention arms of the BREATHE trial.

PubMed

Arden-Close, Emily; Yardley, Lucy; Kirby, Sarah; Thomas, Mike; Bruton, Anne

2017-10-05

Poor symptom control and impaired quality of life are common in adults with asthma, and breathing retraining exercises may be an effective method of self-management. This study aimed to explore the experiences of participants in the intervention arms of the BREATHE trial, which investigated the effectiveness of breathing retraining as a mode of asthma management. Sixteen people with asthma (11 women, 8 per group) who had taken part in the intervention arms of the BREATHE trial (breathing retraining delivered by digital versatile disc (DVD) or face-to-face sessions with a respiratory physiotherapist) took part in semi-structured telephone interviews about their experiences. Interviews were analysed using thematic analysis. Breathing retraining was perceived positively as a method of asthma management. Motivations for taking part included being asked, to enhance progress in research, to feel better/reduce symptoms, and to reduce medication. Participants were positive about the physiotherapist, liked having the materials tailored, found meetings motivational, and liked the DVD and booklet. The impact of breathing retraining following regular practice included increased awareness of breathing and development of new habits. Benefits of breathing retraining included increased control over breathing, reduced need for medication, feeling more relaxed, and improved health and quality of life. Problems included finding time to practice the exercises, and difficulty mastering techniques. Breathing retraining was acceptable and valued by almost all participants, and many reported improved wellbeing. Face to face physiotherapy was well received. However, some participants in the DVD group mentioned being unable to master techniques. PATIENTS RECEPTIVE TO BREATHING RETRAINING: Patients with asthma taught how to change their unconscious breathing patterns generally like non-pharmacological interventions. Researchers in the UK, led by Mike Thomas from the University of Southampton, interviewed 16 people about their experiences in a trial that tested breathing retraining exercises delivered by DVD or face-to-face sessions with a respiratory physiotherapist. Overwhelmingly, trial participants reported that breathing retraining sessions gave them greater control over their symptoms, helped them relax, improved their quality of life and reduced the need for medications. Some participants who received DVD instruction said they had trouble mastering the techniques, and many in both groups found it hard to find time to practice the exercises. Overall, however, patients were positive about the experience. The authors conclude that breathing exercises are likely to be a well-received method of asthma management.

Evaluation of Bio-VOC Sampler for Analysis of Volatile Organic Compounds in Exhaled Breath

PubMed Central

Kwak, Jae; Fan, Maomian; Harshman, Sean W.; Garrison, Catherine E.; Dershem, Victoria L.; Phillips, Jeffrey B.; Grigsby, Claude C.; Ott, Darrin K.

2014-01-01

Monitoring volatile organic compounds (VOCs) from exhaled breath has been used to determine exposures of humans to chemicals. Prior to analysis of VOCs, breath samples are often collected with canisters or bags and concentrated. The Bio-VOC breath sampler, a commercial sampling device, has been recently introduced to the market with growing use. The main advantage for this sampler is to collect the last portion of exhaled breath, which is more likely to represent the air deep in the lungs. However, information about the Bio-VOC sampler is somewhat limited. Therefore, we have thoroughly evaluated the sampler here. We determined the volume of the breath air collected in the sampler was approximately 88 mL. When sampling was repeated multiple times, with the succeeding exhalations applied to a single sorbent tube, we observed linear relationships between the normalized peak intensity and the number of repeated collections with the sampler in many of the breath VOCs detected. No moisture effect was observed on the Tenax sorbent tubes used. However, due to the limitation in the collection volume, the use of the Bio-VOC sampler is recommended only for detection of VOCs present at high concentrations unless repeated collections of breath samples on the sampler are conducted. PMID:25532709

The analysis of volatile organic compounds in exhaled breath and biomarkers in exhaled breath condensate in children - clinical tools or scientific toys?

PubMed

van Mastrigt, E; de Jongste, J C; Pijnenburg, M W

2015-07-01

Current monitoring strategies for respiratory diseases are mainly based on clinical features, lung function and imaging. As airway inflammation is the hallmark of many respiratory diseases in childhood, noninvasive methods to assess the presence and severity of airway inflammation might be helpful in both diagnosing and monitoring paediatric respiratory diseases. At present, the measurement of fractional exhaled nitric oxide is the only noninvasive method available to assess eosinophilic airway inflammation in clinical practice. We aimed to evaluate whether the analysis of volatile organic compounds (VOCs) in exhaled breath (EB) and biomarkers in exhaled breath condensate (EBC) is helpful in diagnosing and monitoring respiratory diseases in children. An extensive literature search was conducted in Medline, Embase and PubMed on the analysis and applications of VOCs in EB and EBC in children. We retrieved 1165 papers, of which nine contained original data on VOCs in EB and 84 on biomarkers in EBC. These were included in this review. We give an overview of the clinical applications in childhood and summarize the methodological issues. Several VOCs in EB and biomarkers in EBC have the potential to distinguish patients from healthy controls and to monitor treatment responses. Lack of standardization of collection methods and analysis techniques hampers the introduction in clinical practice. The measurement of metabolomic profiles may have important advantages over detecting single markers. There is a lack of longitudinal studies and external validation to reveal whether EB and EBC analysis have added value in the diagnostic process and follow-up of children with respiratory diseases. In conclusion, the use of VOCs in EB and biomarkers in EBC as markers of inflammatory airway diseases in children is still a research tool and not validated for clinical use. © 2014 John Wiley & Sons Ltd.

Simple quality assurance method of dynamic tumor tracking with the gimbaled linac system using a light field.

PubMed

Miura, Hideharu; Ozawa, Shuichi; Hayata, Masahiro; Tsuda, Shintaro; Yamada, Kiyoshi; Nagata, Yasushi

2016-09-08

We proposed a simple visual method for evaluating the dynamic tumor tracking (DTT) accuracy of a gimbal mechanism using a light field. A single photon beam was set with a field size of 30 × 30 mm2 at a gantry angle of 90°. The center of a cube phantom was set up at the isocenter of a motion table, and 4D modeling was performed based on the tumor and infrared (IR) marker motion. After 4D modeling, the cube phantom was replaced with a sheet of paper, which was placed perpen-dicularly, and a light field was projected on the sheet of paper. The light field was recorded using a web camera in a treatment room that was as dark as possible. Calculated images from each image obtained using the camera were summed to compose a total summation image. Sinusoidal motion sequences were produced by moving the phantom with a fixed amplitude of 20 mm and different breathing periods of 2, 4, 6, and 8 s. The light field was projected on the sheet of paper under three conditions: with the moving phantom and DTT based on the motion of the phantom, with the moving phantom and non-DTT, and with a stationary phantom for comparison. The values of tracking errors using the light field were 1.12 ± 0.72, 0.31 ± 0.19, 0.27 ± 0.12, and 0.15 ± 0.09 mm for breathing periods of 2, 4, 6, and 8s, respectively. The tracking accuracy showed dependence on the breath-ing period. We proposed a simple quality assurance (QA) process for the tracking accuracy of a gimbal mechanism system using a light field and web camera. Our method can assess the tracking accuracy using a light field without irradiation and clearly visualize distributions like film dosimetry. © 2016 The Authors.

Effectiveness of respiratory-gated radiotherapy with audio-visual biofeedback for synchrotron-based scanned heavy-ion beam delivery

NASA Astrophysics Data System (ADS)

He, Pengbo; Li, Qiang; Zhao, Ting; Liu, Xinguo; Dai, Zhongying; Ma, Yuanyuan

2016-12-01

A synchrotron-based heavy-ion accelerator operates in pulse mode at a low repetition rate that is comparable to a patient’s breathing rate. To overcome inefficiencies and interplay effects between the residual motion of the target and the scanned heavy-ion beam delivery process for conventional free breathing (FB)-based gating therapy, a novel respiratory guidance method was developed to help patients synchronize their breathing patterns with the synchrotron excitation patterns by performing short breath holds with the aid of personalized audio-visual biofeedback (BFB) system. The purpose of this study was to evaluate the treatment precision, efficiency and reproducibility of the respiratory guidance method in scanned heavy-ion beam delivery mode. Using 96 breathing traces from eight healthy volunteers who were asked to breathe freely and guided to perform short breath holds with the aid of BFB, a series of dedicated four-dimensional dose calculations (4DDC) were performed on a geometric model which was developed assuming a linear relationship between external surrogate and internal tumor motions. The outcome of the 4DDCs was quantified in terms of the treatment time, dose-volume histograms (DVH) and dose homogeneity index. Our results show that with the respiratory guidance method the treatment efficiency increased by a factor of 2.23-3.94 compared with FB gating, depending on the duty cycle settings. The magnitude of dose inhomogeneity for the respiratory guidance methods was 7.5 times less than that of the non-gated irradiation, and good reproducibility of breathing guidance among different fractions was achieved. Thus, our study indicates that the respiratory guidance method not only improved the overall treatment efficiency of respiratory-gated scanned heavy-ion beam delivery, but also had the advantages of lower dose uncertainty and better reproducibility among fractions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiely, J Blanco; Olszanski, A; Both, S

Purpose: To develop a quantitative decision making metric for automatically detecting irregular breathing using a large patient population that received phase-sorted 4DCT. Methods: This study employed two patient cohorts. Cohort#1 contained 256 patients who received a phasesorted 4DCT. Cohort#2 contained 86 patients who received three weekly phase-sorted 4DCT scans. A previously published technique used a single abdominal surrogate to calculate the ratio of extreme inhalation tidal volume to normal inhalation tidal volume, referred to as the κ metric. Since a single surrogate is standard for phase-sorted 4DCT in radiation oncology clinical practice, tidal volume was not quantified. Without tidal volume,more » the absolute κ metric could not be determined, so a relative κ (κrel) metric was defined based on the measured surrogate amplitude instead of tidal volume. Receiver operator characteristic (ROC) curves were used to quantitatively determine the optimal cutoff value (jk) and efficiency cutoff value (τk) of κrel to automatically identify irregular breathing that would reduce the image quality of phase-sorted 4DCT. Discriminatory accuracy (area under the ROC curve) of κrel was calculated by a trapezoidal numeric integration technique. Results: The discriminatory accuracy of ?rel was found to be 0.746. The key values of jk and tk were calculated to be 1.45 and 1.72 respectively. For values of ?rel such that jk≤κrel≤τk, the decision to reacquire the 4DCT would be at the discretion of the physician. This accounted for only 11.9% of the patients in this study. The magnitude of κrel held consistent over 3 weeks for 73% of the patients in cohort#3. Conclusion: The decision making metric, ?rel, was shown to be an accurate classifier of irregular breathing patients in a large patient population. This work provided an automatic quantitative decision making metric to quickly and accurately assess the extent to which irregular breathing is occurring during phase-sorted 4DCT.« less

Extraction and Analysis of Respiratory Motion Using Wearable Inertial Sensor System during Trunk Motion

PubMed Central

Gaidhani, Apoorva; Moon, Kee S.; Ozturk, Yusuf; Lee, Sung Q.; Youm, Woosub

2017-01-01

Respiratory activity is an essential vital sign of life that can indicate changes in typical breathing patterns and irregular body functions such as asthma and panic attacks. Many times, there is a need to monitor breathing activity while performing day-to-day functions such as standing, bending, trunk stretching or during yoga exercises. A single IMU (inertial measurement unit) can be used in measuring respiratory motion; however, breathing motion data may be influenced by a body trunk movement that occurs while recording respiratory activity. This research employs a pair of wireless, wearable IMU sensors custom-made by the Department of Electrical Engineering at San Diego State University. After appropriate sensor placement for data collection, this research applies principles of robotics, using the Denavit-Hartenberg convention, to extract relative angular motion between the two sensors. One of the obtained relative joint angles in the “Sagittal” plane predominantly yields respiratory activity. An improvised version of the proposed method and wearable, wireless sensors can be suitable to extract respiratory information while performing sports or exercises, as they do not restrict body motion or the choice of location to gather data. PMID:29258214

Breathing Pattern Interpretation as an Alternative and Effective Voice Communication Solution.

PubMed

Elsahar, Yasmin; Bouazza-Marouf, Kaddour; Kerr, David; Gaur, Atul; Kaushik, Vipul; Hu, Sijung

2018-05-15

Augmentative and alternative communication (AAC) systems tend to rely on the interpretation of purposeful gestures for interaction. Existing AAC methods could be cumbersome and limit the solutions in terms of versatility. The study aims to interpret breathing patterns (BPs) to converse with the outside world by means of a unidirectional microphone and researches breathing-pattern interpretation (BPI) to encode messages in an interactive manner with minimal training. We present BP processing work with (1) output synthesized machine-spoken words (SMSW) along with single-channel Weiner filtering (WF) for signal de-noising, and (2) k -nearest neighbor ( k-NN ) classification of BPs associated with embedded dynamic time warping (DTW). An approved protocol to collect analogue modulated BP sets belonging to 4 distinct classes with 10 training BPs per class and 5 live BPs per class was implemented with 23 healthy subjects. An 86% accuracy of k-NN classification was obtained with decreasing error rates of 17%, 14%, and 11% for the live classifications of classes 2, 3, and 4, respectively. The results express a systematic reliability of 89% with increased familiarity. The outcomes from the current AAC setup recommend a durable engineering solution directly beneficial to the sufferers.

A prospective gating method to acquire a diverse set of free-breathing CT images for model-based 4DCT

NASA Astrophysics Data System (ADS)

O'Connell, D.; Ruan, D.; Thomas, D. H.; Dou, T. H.; Lewis, J. H.; Santhanam, A.; Lee, P.; Low, D. A.

2018-02-01

Breathing motion modeling requires observation of tissues at sufficiently distinct respiratory states for proper 4D characterization. This work proposes a method to improve sampling of the breathing cycle with limited imaging dose. We designed and tested a prospective free-breathing acquisition protocol with a simulation using datasets from five patients imaged with a model-based 4DCT technique. Each dataset contained 25 free-breathing fast helical CT scans with simultaneous breathing surrogate measurements. Tissue displacements were measured using deformable image registration. A correspondence model related tissue displacement to the surrogate. Model residual was computed by comparing predicted displacements to image registration results. To determine a stopping criteria for the prospective protocol, i.e. when the breathing cycle had been sufficiently sampled, subsets of N scans where 5  ⩽  N  ⩽  9 were used to fit reduced models for each patient. A previously published metric was employed to describe the phase coverage, or ‘spread’, of the respiratory trajectories of each subset. Minimum phase coverage necessary to achieve mean model residual within 0.5 mm of the full 25-scan model was determined and used as the stopping criteria. Using the patient breathing traces, a prospective acquisition protocol was simulated. In all patients, phase coverage greater than the threshold necessary for model accuracy within 0.5 mm of the 25 scan model was achieved in six or fewer scans. The prospectively selected respiratory trajectories ranked in the (97.5  ±  4.2)th percentile among subsets of the originally sampled scans on average. Simulation results suggest that the proposed prospective method provides an effective means to sample the breathing cycle with limited free-breathing scans. One application of the method is to reduce the imaging dose of a previously published model-based 4DCT protocol to 25% of its original value while achieving mean model residual within 0.5 mm.

Improved Pharmacokinetics of Sumatriptan With Breath Powered™ Nasal Delivery of Sumatriptan Powder

PubMed Central

Obaidi, Mohammad; Offman, Elliot; Messina, John; Carothers, Jennifer; Djupesland, Per G; Mahmoud, Ramy A

2013-01-01

Objectives.— The purpose of this study was to directly compare the pharmacokinetic (PK) profile of 22-mg sumatriptan powder delivered intranasally with a novel Breath Powered™ device (11 mg in each nostril) vs a 20-mg sumatriptan liquid nasal spray, a 100-mg oral tablet, and a 6-mg subcutaneous injection. Background.— A prior PK study found that low doses of sumatriptan powder delivered intranasally with a Breath Powered device were efficiently and rapidly absorbed. An early phase clinical trial with the same device and doses found excellent tolerability with high response rates and rapid onset of pain relief, approaching the benefits of injection despite significantly lower predicted drug levels. Methods.— An open-label, cross-over, comparative bioavailability study was conducted in 20 healthy subjects at a single center in the USA. Following randomization, fasted subjects received a single dose of each of the 4 treatments separated by a 7-day washout. Blood samples were taken pre-dose and serially over 14 hours post-dose for PK analysis. Results.— Quantitative measurement of residuals in used Breath Powered devices demonstrated that the devices delivered 8 ± 0.9 mg (mean ± standard deviation) of sumatriptan powder in each nostril (total dose 16 mg). Although the extent of systemic exposure over 14 hours was similar following Breath Powered delivery of 16-mg sumatriptan powder and 20-mg liquid nasal spray (area under the curve [AUC]0-∞ 64.9 ng*hour/mL vs 61.1 ng*hour/mL), sumatriptan powder, despite a 20% lower dose, produced 27% higher peak exposure (Cmax 20.8 ng/mL vs 16.4 ng/mL) and 61% higher exposure in the first 30 minutes compared with the nasal spray (AUC0-30 minutes 5.8 ng*hour/mL vs 3.6 ng*hour/mL). The magnitude of difference is larger on a per-milligram basis. The absorption profile following standard nasal spray demonstrated bimodal peaks, consistent with lower early followed by higher later absorptions. In contrast, the profile following Breath Powered delivery showed higher early and lower late absorptions. Relative to the 100-mg oral tablet (Cmax 70.2 ng/mL, AUC0-∞, 308.8 ng*hour/mL) and 6-mg injection (Cmax 111.6 ng/mL, AUC0-∞ 128.2 ng*hour/mL), the peak and overall exposure following Breath Powered intranasal delivery of sumatriptan powder was substantially lower. Conclusions.— Breath Powered intranasal delivery of sumatriptan powder is a more efficient form of drug delivery, producing a higher peak and earlier exposure with a lower delivered dose than nasal spray and faster absorption than either nasal spray or oral administration. It also produces a significantly lower peak and total systemic exposure than oral tablet or subcutaneous injection. PMID:23992438

Imaging Breathing Rate in the CO2Absorption Band.

PubMed

Fei, Jin; Zhu, Zhen; Pavlidis, Ioannis

2005-01-01

Following up on our previous work, we have developed one more non-contact method to measure human breathing rate. We have retrofitted our Mid-Wave Infra-Red (MWIR) imaging system with a narrow band-pass filter in the CO2absorption band (4.3 µm). This improves the contrast between the foreground (i.e., expired air) and background (e.g., wall). Based on the radiation information within the breath flow region, we get the mean dynamic thermal signal. This signal is quasi-periodic due to the interleaving of high and low intensities corresponding to expirations and inspirations respectively. We sample the signal at a constant rate and then determine the breathing frequency through Fourier analysis. We have performed experiments on 9 subjects at distances ranging from 6-8 ft. We compared the breathing rate computed by our novel method with ground-truth measurements obtained via a traditional contact device (PowerLab/4SP from ADInstruments with an abdominal transducer). The results show high correlation between the two modalities. For the first time, we report a Fourier based breathing rate computation method on a MWIR signal in the CO2absorption band. The method opens the way for desktop, unobtrusive monitoring of an important vital sign, that is, breathing rate. It may find widespread applications in preventive medicine as well as sustained physiological monitoring of subjects suffering from chronic ailments.

Electret filter collects more exhaled albumin than glass condenser: A method comparison based on human study.

PubMed

Jia, Ziru; Liu, Hongying; Li, Wang; Xie, Dandan; Cheng, Ke; Pi, Xitian

2018-02-01

In recent years, noninvasive diagnosis based on biomarkers in exhaled breath has been extensively studied. The procedure of biomarker collection is a key step. However, the traditional condenser method has low efficacy in collecting nonvolatile compounds especially the protein biomarkers in breath. To solve this deficiency, here we propose an electret filter method.Exhaled breath of 6 volunteers was collected with a glass condenser and an electret filter. The amount of albumin was analyzed. Furthermore, the difference of exhaled albumin between smokers and nonsmokers was evaluated.The electret filter method collected more albumin than the glass condenser method at the same breath volume level (P < .01). Smokers exhaling more albumin than nonsmokers were also observed (P < .01).The electret filter is capable of collecting proteins more effectively than the condenser method. In addition, smokers tend to exhale more albumin than nonsmokers.

Recovery of Percent Vital Capacity by Breathing Training in Patients With Panic Disorder and Impaired Diaphragmatic Breathing.

PubMed

Yamada, Tatsuji; Inoue, Akiomi; Mafune, Kosuke; Hiro, Hisanori; Nagata, Shoji

2017-09-01

Slow diaphragmatic breathing is one of the therapeutic methods used in behavioral therapy for panic disorder. In practice, we have noticed that some of these patients could not perform diaphragmatic breathing and their percent vital capacity was initially reduced but could be recovered through breathing training. We conducted a comparative study with healthy controls to investigate the relationship between diaphragmatic breathing ability and percent vital capacity in patients with panic disorder. Our findings suggest that percent vital capacity in patients with impaired diaphragmatic breathing was significantly reduced compared with those with normal diaphragmatic breathing and that diaphragmatic breathing could be restored by breathing training. Percent vital capacity of the healthy controls was equivalent to that of the patients who had completed breathing training. This article provides preliminary findings regarding reduced vital capacity in relation to abnormal respiratory movements found in patients with panic disorder, potentially offering alternative perspectives for verifying the significance of breathing training for panic disorder.

Increasing conclusiveness of clinical breath analysis by improved baseline correction of multi capillary column - ion mobility spectrometry (MCC-IMS) data.

PubMed

Szymańska, Ewa; Tinnevelt, Gerjen H; Brodrick, Emma; Williams, Mark; Davies, Antony N; van Manen, Henk-Jan; Buydens, Lutgarde M C

2016-08-05

Current challenges of clinical breath analysis include large data size and non-clinically relevant variations observed in exhaled breath measurements, which should be urgently addressed with competent scientific data tools. In this study, three different baseline correction methods are evaluated within a previously developed data size reduction strategy for multi capillary column - ion mobility spectrometry (MCC-IMS) datasets. Introduced for the first time in breath data analysis, the Top-hat method is presented as the optimum baseline correction method. A refined data size reduction strategy is employed in the analysis of a large breathomic dataset on a healthy and respiratory disease population. New insights into MCC-IMS spectra differences associated with respiratory diseases are provided, demonstrating the additional value of the refined data analysis strategy in clinical breath analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous Measurement of Breathing and Heartbeat using Airborne Ultrasound in a Standing Position

NASA Astrophysics Data System (ADS)

Hoshiba, Kotaro; Hirata, Shinnosuke; Hachiya, Hiroyuki

We have been studied about non-contact measurement of respiration and heart rates. In previous papers, the measurement system of small velocity using the M-sequence-modulated signal and phase difference of reflected signals from the target has been proposed. In this paper, we describe measurement of breathing and heartbeat in a standing position using the proposed method. Body-surface velocities by breathing and heartbeat could be observed respectively when the volunteer was breathing and holding the breath. In addition, measured velocity of breathing volunteer includes the component by heartbeat. It is considered that it has possibility to measure breathing and heartbeat concurrently.

Refinement of Speech Breathing in Healthy 4- to 6-Year-Old Children

ERIC Educational Resources Information Center

Boliek, Carol A.; Hixon, Thomas J.; Watson, Peter J.; Jones, Patricia B.

2009-01-01

Purpose: The purpose of this study was to offer a better understanding of the development of neuromotor control for speech breathing and provide a normative data set that can serve as a useful standard for clinical evaluation and management of young children with speech disorders involving the breathing subsystem. Method: Speech breathing was…

Comparison of breathing gated CT images generated using a 5DCT technique and a commercial clinical protocol in a porcine model

PubMed Central

O’Connell, Dylan P.; Thomas, David H.; Dou, Tai H.; Lamb, James M.; Feingold, Franklin; Low, Daniel A.; Fuld, Matthew K.; Sieren, Jered P.; Sloan, Chelsea M.; Shirk, Melissa A.; Hoffman, Eric A.; Hofmann, Christian

2015-01-01

Purpose: To demonstrate that a “5DCT” technique which utilizes fast helical acquisition yields the same respiratory-gated images as a commercial technique for regular, mechanically produced breathing cycles. Methods: Respiratory-gated images of an anesthetized, mechanically ventilated pig were generated using a Siemens low-pitch helical protocol and 5DCT for a range of breathing rates and amplitudes and with standard and low dose imaging protocols. 5DCT reconstructions were independently evaluated by measuring the distances between tissue positions predicted by a 5D motion model and those measured using deformable registration, as well by reconstructing the originally acquired scans. Discrepancies between the 5DCT and commercial reconstructions were measured using landmark correspondences. Results: The mean distance between model predicted tissue positions and deformably registered tissue positions over the nine datasets was 0.65 ± 0.28 mm. Reconstructions of the original scans were on average accurate to 0.78 ± 0.57 mm. Mean landmark displacement between the commercial and 5DCT images was 1.76 ± 1.25 mm while the maximum lung tissue motion over the breathing cycle had a mean value of 27.2 ± 4.6 mm. An image composed of the average of 30 deformably registered images acquired with a low dose protocol had 6 HU image noise (single standard deviation) in the heart versus 31 HU for the commercial images. Conclusions: An end to end evaluation of the 5DCT technique was conducted through landmark based comparison to breathing gated images acquired with a commercial protocol under highly regular ventilation. The techniques were found to agree to within 2 mm for most respiratory phases and most points in the lung. PMID:26133604

DOE Office of Scientific and Technical Information (OSTI.GOV)

Depauw, N; Patel, S; MacDonald, S

Purpose: Deep inspiration breath-hold techniques (DIBH) have been shown to carry significant dosimetric advantages in conventional radiotherapy of left-sided breast cancer. The purpose of this study is to evaluate the use of DIBH techniques for post-mastectomy radiation therapy (PMRT) using proton pencil beam scanning (PBS). Method: Ten PMRT patients, with or without breast implant, underwent two helical CT scans: one with free breathing and the other with deep inspiration breath-hold. A prescription of 50.4 Gy(RBE) to the whole chest wall and lymphatics (axillary, supraclavicular, and intramammary nodes) was considered. PBS plans were generated for each patient’s CT scan using Astroid,more » an in-house treatment planning system, with the institution conventional clinical PMRT parameters; that is, using a single en-face field with a spot size varying from 8 mm to 14 mm as a function of energy. Similar optimization parameters were used in both plans in order to ensure appropriate comparison. Results: Regardless of the technique (free breathing or DIBH), the generated plans were well within clinical acceptability. DIBH allowed for higher target coverage with better sparing of the cardiac structures. The lung doses were also slightly improved. While the use of DIBH techniques might be of interest, it is technically challenging as it would require a fast PBS delivery, as well as the synchronization of the beam delivery with a gating system, both of which are not currently available at the institution. Conclusion: DIBH techniques display some dosimetric advantages over free breathing treatment for PBS PMRT patients, which warrants further investigation. Plans will also be generated with smaller spot sizes (2.5 mm to 5.5 mm and 5 mm to 9 mm), corresponding to new generation machines, in order to further quantify the dosimetric advantages of DIBH as a function of spot size.« less

Clinical research on liver reserve function by 13C-phenylalanine breath test in aged patients with chronic liver diseases

PubMed Central

2010-01-01

Background The objective of this study was to investigate whether the 13C-phenylalanine breath test could be useful for the evaluation of hepatic function in elderly volunteers and patients with chronic hepatitis B and liver cirrhosis. Methods L-[1-13C] phenylalanine was administered orally at a dose of 100 mg to 55 elderly patients with liver cirrhosis, 30 patients with chronic hepatitis B and 38 elderly healthy subjects. The breath test was performed at 8 different time points (0, 10, 20, 30, 45, 60, 90, 120 min) to obtain the values of Delta over baseline, percentage 13CO2 exhalation rate and cumulative excretion (Cum). The relationships of the cumulative excretion with the 13C-%dose/h and blood biochemical parameters were investigated. Results The 13C-%dose/h at 20 min and 30 min combined with the cumulative excretion at 60 min and 120 min correlated with hepatic function tests, serum albumin, hemoglobin, platelet and Child-Pugh score. Prothrombin time, total and direct bilirubin were significantly increased, while serum albumin, hemoglobin and platelet, the cumulative excretion at 60 min and 120 min values decreased by degrees of intensity of the disease in Child-Pugh A, B, and C patients (P < 0.01). Conclusions The 13C-phenylalanine breath test can be used as a non-invasive assay to evaluate hepatic function in elderly patients with liver cirrhosis. The 13C-%dose/h at 20 min, at 30 min and cumulative excretion at 60 min may be the key value for determination at a single time-point. 13C-phenylalanine breath test is safe and helpful in distinguishing different stages of hepatic dysfunction for elderly cirrhosis patients. PMID:20459849

The effects of Pilates breathing trainings on trunk muscle activation in healthy female subjects: a prospective study

PubMed Central

Kim, Sung-Tae; Lee, Joon-Hee

2017-01-01

[Purpose] To investigate the effects of Pilates breathing on trunk muscle activation. [Subjects and Methods] Twenty-eight healthy female adults were selected for this study. Participants’ trunk muscle activations were measured while they performed curl-ups, chest-head lifts, and lifting tasks. Pilates breathing trainings were performed for 60 minutes per each session, 3 times per week for 2 weeks. Post-training muscle activations were measured by the same methods used for the pre-training muscle activations. [Results] All trunk muscles measured in this study had increased activities after Pilates breathing trainings. All activities of the transversus abdominis/internal abdominal oblique, and multifidus significantly increased. [Conclusion] Pilates breathing increased activities of the trunk stabilizer muscles. Activation of the trunk muscle indicates that practicing Pilates breathing while performing lifting tasks will reduce the risk of trunk injuries. PMID:28265138

The effects of Pilates breathing trainings on trunk muscle activation in healthy female subjects: a prospective study.

PubMed

Kim, Sung-Tae; Lee, Joon-Hee

2017-02-01

[Purpose] To investigate the effects of Pilates breathing on trunk muscle activation. [Subjects and Methods] Twenty-eight healthy female adults were selected for this study. Participants' trunk muscle activations were measured while they performed curl-ups, chest-head lifts, and lifting tasks. Pilates breathing trainings were performed for 60 minutes per each session, 3 times per week for 2 weeks. Post-training muscle activations were measured by the same methods used for the pre-training muscle activations. [Results] All trunk muscles measured in this study had increased activities after Pilates breathing trainings. All activities of the transversus abdominis/internal abdominal oblique, and multifidus significantly increased. [Conclusion] Pilates breathing increased activities of the trunk stabilizer muscles. Activation of the trunk muscle indicates that practicing Pilates breathing while performing lifting tasks will reduce the risk of trunk injuries.

Application of drug testing using exhaled breath for compliance monitoring of drug addicts in treatment.

PubMed

Carlsson, Sten; Olsson, Robert; Lindkvist, Irene; Beck, Olof

2015-04-01

Exhaled breath has recently been identified as a possible matrix for drug testing. This study explored the potential of this new method for compliance monitoring of patients being treated for dependence disorders. Outpatients in treatment programs were recruited for this study. Urine was collected as part of clinical routine and a breath sample was collected in parallel together with a questionnaire about their views of the testing procedure. Urine was analyzed for amphetamines, benzodiazepines, cannabis, cocaine, buprenorphine, methadone and opiates using CEDIA immunochemical screening and mass spectrometry confirmation. The exhaled breath was collected using the SensAbues device and analyzed by mass spectrometry for amphetamine, methamphetamine, diazepam, oxazepam, tetrahydrocannabinol, cocaine, benzoylecgonine, buprenorphine, methadone, morphine, codeine and 6-acetylmorphine. A total of 122 cases with parallel urine and breath samples were collected; 34 of these were negative both in urine and breath. Out of 88 cases with positive urine samples 51 (58%) were also positive in breath. Among the patients on methadone treatment, all were positive for methadone in urine and 83% were positive in breath. Among patients in treatment with buprenorphine, 92% were positive in urine and among those 80% were also positive in breath. The questionnaire response documented that in general, patients accepted drug testing well and that the breath sampling procedure was preferred. Compliance testing for the intake of prescribed and unprescribed drugs among patients in treatment for dependence disorders using the exhaled breath sampling technique is a viable method and deserves future attention.

Human breath metabolomics using an optimized noninvasive exhaled breath condensate sampler

PubMed Central

Zamuruyev, Konstantin O.; Aksenov, Alexander A.; Pasamontes, Alberto; Brown, Joshua F.; Pettit, Dayna R.; Foutouhi, Soraya; Weimer, Bart C.; Schivo, Michael; Kenyon, Nicholas J.; Delplanque, Jean-Pierre; Davis, Cristina E.

2017-01-01

Exhaled breath condensate (EBC) analysis is a developing field with tremendous promise to advance personalized, non-invasive health diagnostics as new analytical instrumentation platforms and detection methods are developed. Multiple commercially-available and researcher-built experimental samplers are reported in the literature. However, there is very limited information available to determine an effective breath sampling approach, especially regarding the dependence of breath sample metabolomic content on the collection device design and sampling methodology. This lack of an optimal standard procedure results in a range of reported results that are sometimes contradictory. Here, we present a design of a portable human EBC sampler optimized for collection and preservation of the rich metabolomic content of breath. The performance of the engineered device is compared to two commercially available breath collection devices: the RTube™ and TurboDECCS. A number of design and performance parameters are considered, including: condenser temperature stability during sampling, collection efficiency, condenser material choice, and saliva contamination in the collected breath samples. The significance of the biological content of breath samples, collected with each device, is evaluated with a set of mass spectrometry methods and was the primary factor for evaluating device performance. The design includes an adjustable mass-size threshold for aerodynamic filtering of saliva droplets from the breath flow. Engineering an inexpensive device that allows efficient collection of metalomic-rich breath samples is intended to aid further advancement in the field of breath analysis for non-invasive health diagnostic. EBC sampling from human volunteers was performed under UC Davis IRB protocol 63701-3 (09/30/2014-07/07/2017). PMID:28004639

Human breath metabolomics using an optimized non-invasive exhaled breath condensate sampler.

PubMed

Zamuruyev, Konstantin O; Aksenov, Alexander A; Pasamontes, Alberto; Brown, Joshua F; Pettit, Dayna R; Foutouhi, Soraya; Weimer, Bart C; Schivo, Michael; Kenyon, Nicholas J; Delplanque, Jean-Pierre; Davis, Cristina E

2016-12-22

Exhaled breath condensate (EBC) analysis is a developing field with tremendous promise to advance personalized, non-invasive health diagnostics as new analytical instrumentation platforms and detection methods are developed. Multiple commercially-available and researcher-built experimental samplers are reported in the literature. However, there is very limited information available to determine an effective breath sampling approach, especially regarding the dependence of breath sample metabolomic content on the collection device design and sampling methodology. This lack of an optimal standard procedure results in a range of reported results that are sometimes contradictory. Here, we present a design of a portable human EBC sampler optimized for collection and preservation of the rich metabolomic content of breath. The performance of the engineered device is compared to two commercially available breath collection devices: the RTube ™ and TurboDECCS. A number of design and performance parameters are considered, including: condenser temperature stability during sampling, collection efficiency, condenser material choice, and saliva contamination in the collected breath samples. The significance of the biological content of breath samples, collected with each device, is evaluated with a set of mass spectrometry methods and was the primary factor for evaluating device performance. The design includes an adjustable mass-size threshold for aerodynamic filtering of saliva droplets from the breath flow. Engineering an inexpensive device that allows efficient collection of metalomic-rich breath samples is intended to aid further advancement in the field of breath analysis for non-invasive health diagnostic. EBC sampling from human volunteers was performed under UC Davis IRB protocol 63701-3 (09/30/2014-07/07/2017).

A 4DCT imaging-based breathing lung model with relative hysteresis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyawaki, Shinjiro; Choi, Sanghun; Hoffman, Eric A.

To reproduce realistic airway motion and airflow, the authors developed a deforming lung computational fluid dynamics (CFD) model based on four-dimensional (4D, space and time) dynamic computed tomography (CT) images. A total of 13 time points within controlled tidal volume respiration were used to account for realistic and irregular lung motion in human volunteers. Because of the irregular motion of 4DCT-based airways, we identified an optimal interpolation method for airway surface deformation during respiration, and implemented a computational solid mechanics-based moving mesh algorithm to produce smooth deforming airway mesh. In addition, we developed physiologically realistic airflow boundary conditions for bothmore » models based on multiple images and a single image. Furthermore, we examined simplified models based on one or two dynamic or static images. By comparing these simplified models with the model based on 13 dynamic images, we investigated the effects of relative hysteresis of lung structure with respect to lung volume, lung deformation, and imaging methods, i.e., dynamic vs. static scans, on CFD-predicted pressure drop. The effect of imaging method on pressure drop was 24 percentage points due to the differences in airflow distribution and airway geometry. - Highlights: • We developed a breathing human lung CFD model based on 4D-dynamic CT images. • The 4DCT-based breathing lung model is able to capture lung relative hysteresis. • A new boundary condition for lung model based on one static CT image was proposed. • The difference between lung models based on 4D and static CT images was quantified.« less

Electret filter collects more exhaled albumin than glass condenser

PubMed Central

Jia, Ziru; Liu, Hongying; Li, Wang; Xie, Dandan; Cheng, Ke; Pi, Xitian

2018-01-01

Abstract In recent years, noninvasive diagnosis based on biomarkers in exhaled breath has been extensively studied. The procedure of biomarker collection is a key step. However, the traditional condenser method has low efficacy in collecting nonvolatile compounds especially the protein biomarkers in breath. To solve this deficiency, here we propose an electret filter method. Exhaled breath of 6 volunteers was collected with a glass condenser and an electret filter. The amount of albumin was analyzed. Furthermore, the difference of exhaled albumin between smokers and nonsmokers was evaluated. The electret filter method collected more albumin than the glass condenser method at the same breath volume level (P < .01). Smokers exhaling more albumin than nonsmokers were also observed (P < .01). The electret filter is capable of collecting proteins more effectively than the condenser method. In addition, smokers tend to exhale more albumin than nonsmokers. PMID:29384875

Prospective MR image alignment between breath-holds: Application to renal BOLD MRI.

PubMed

Kalis, Inge M; Pilutti, David; Krafft, Axel J; Hennig, Jürgen; Bock, Michael

2017-04-01

To present an image registration method for renal blood oxygen level-dependent (BOLD) measurements that enables semiautomatic assessment of parenchymal and medullary R2* changes under a functional challenge. In a series of breath-hold acquisitions, three-dimensional data were acquired initially for prospective image registration of subsequent BOLD measurements. An algorithm for kidney alignment for BOLD renal imaging (KALIBRI) was implemented to detect the positions of the left and right kidney so that the kidneys were acquired in the subsequent BOLD measurement at consistent anatomical locations. Residual in-plane distortions were corrected retrospectively so that semiautomatic dynamic R2* measurements of the renal cortex and medulla become feasible. KALIBRI was tested in six healthy volunteers during a series of BOLD experiments, which included a 600- to 1000-mL water challenge. Prospective image registration and BOLD imaging of each kidney was achieved within a total measurement time of about 17 s, enabling its execution within a single breath-hold. KALIBRI improved the registration by up to 35% as found with mutual information measures. In four volunteers, a medullary R2* decrease of up to 40% was observed after water ingestion. KALIBRI improves the quality of two-dimensional time-resolved renal BOLD MRI by aligning local renal anatomy, which allows for consistent R2* measurements over many breath-holds. Magn Reson Med 77:1573-1582, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Does alcohol contribute to accident and emergency department attendance in elderly people?

PubMed Central

van der Pol, V; Rodgers, H; Aitken, P; James, O; Curless, R

1996-01-01

OBJECTIVE: To evaluate the possible contribution of alcohol to presentation of elderly subjects at a hospital accident and emergency (A&E) department. METHODS: 105 patients aged 70 years and over who attended the department were interviewed by a single observer using a structured questionnaire based on previously validated general population surveys. Details of alcohol consumption within the previous 24 hours were recorded. Usual consumption of alcohol in the preceding 12 months was estimated by the quantity frequency method. Alcohol dependence was screened for by the CAGE questionnaire. An assessment of disability was made using the Barthel index. Breath alcohol was measured. RESULTS: In only 2% of attenders was alcohol thought to be a contributory factor. Breath alcohol measurements were technically unsatisfactory in this age group. Regular drinkers were functionally and socially more independent than non-regular drinkers. Drinking patterns in this age group may partly be determined by the physical ability to obtain alcohol. CONCLUSIONS: Alcohol was not found to be a major factor in A&E attendance in elderly people. PMID:8832344

From Chicken Breath to the Killer Lakes of Cameroon: Uniting Seven Interesting Phenomena with a Single Chemical Underpinning.

ERIC Educational Resources Information Center

DeLorenzo, Ron

2001-01-01

Recommends integrating different applications to serve the need for students to know the relevancy of the course of their future. Uses different and unrelated phenomena to teach equilibria. Introduces six phenomena; (1) Killer Lakes of Cameroon, (2) Chicken Breath, (3) The Permian Ocean, (4) Snow Line, (5) Hard-Water Boiler Scale, and (6)…

An initial study on the estimation of time-varying volumetric treatment images and 3D tumor localization from single MV cine EPID images

PubMed Central

Mishra, Pankaj; Li, Ruijiang; Mak, Raymond H.; Rottmann, Joerg; Bryant, Jonathan H.; Williams, Christopher L.; Berbeco, Ross I.; Lewis, John H.

2014-01-01

Purpose: In this work the authors develop and investigate the feasibility of a method to estimate time-varying volumetric images from individual MV cine electronic portal image device (EPID) images. Methods: The authors adopt a two-step approach to time-varying volumetric image estimation from a single cine EPID image. In the first step, a patient-specific motion model is constructed from 4DCT. In the second step, parameters in the motion model are tuned according to the information in the EPID image. The patient-specific motion model is based on a compact representation of lung motion represented in displacement vector fields (DVFs). DVFs are calculated through deformable image registration (DIR) of a reference 4DCT phase image (typically peak-exhale) to a set of 4DCT images corresponding to different phases of a breathing cycle. The salient characteristics in the DVFs are captured in a compact representation through principal component analysis (PCA). PCA decouples the spatial and temporal components of the DVFs. Spatial information is represented in eigenvectors and the temporal information is represented by eigen-coefficients. To generate a new volumetric image, the eigen-coefficients are updated via cost function optimization based on digitally reconstructed radiographs and projection images. The updated eigen-coefficients are then multiplied with the eigenvectors to obtain updated DVFs that, in turn, give the volumetric image corresponding to the cine EPID image. Results: The algorithm was tested on (1) Eight digital eXtended CArdiac-Torso phantom datasets based on different irregular patient breathing patterns and (2) patient cine EPID images acquired during SBRT treatments. The root-mean-squared tumor localization error is (0.73 ± 0.63 mm) for the XCAT data and (0.90 ± 0.65 mm) for the patient data. Conclusions: The authors introduced a novel method of estimating volumetric time-varying images from single cine EPID images and a PCA-based lung motion model. This is the first method to estimate volumetric time-varying images from single MV cine EPID images, and has the potential to provide volumetric information with no additional imaging dose to the patient. PMID:25086523

An initial study on the estimation of time-varying volumetric treatment images and 3D tumor localization from single MV cine EPID images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishra, Pankaj, E-mail: pankaj.mishra@varian.com; Mak, Raymond H.; Rottmann, Joerg

2014-08-15

Purpose: In this work the authors develop and investigate the feasibility of a method to estimate time-varying volumetric images from individual MV cine electronic portal image device (EPID) images. Methods: The authors adopt a two-step approach to time-varying volumetric image estimation from a single cine EPID image. In the first step, a patient-specific motion model is constructed from 4DCT. In the second step, parameters in the motion model are tuned according to the information in the EPID image. The patient-specific motion model is based on a compact representation of lung motion represented in displacement vector fields (DVFs). DVFs are calculatedmore » through deformable image registration (DIR) of a reference 4DCT phase image (typically peak-exhale) to a set of 4DCT images corresponding to different phases of a breathing cycle. The salient characteristics in the DVFs are captured in a compact representation through principal component analysis (PCA). PCA decouples the spatial and temporal components of the DVFs. Spatial information is represented in eigenvectors and the temporal information is represented by eigen-coefficients. To generate a new volumetric image, the eigen-coefficients are updated via cost function optimization based on digitally reconstructed radiographs and projection images. The updated eigen-coefficients are then multiplied with the eigenvectors to obtain updated DVFs that, in turn, give the volumetric image corresponding to the cine EPID image. Results: The algorithm was tested on (1) Eight digital eXtended CArdiac-Torso phantom datasets based on different irregular patient breathing patterns and (2) patient cine EPID images acquired during SBRT treatments. The root-mean-squared tumor localization error is (0.73 ± 0.63 mm) for the XCAT data and (0.90 ± 0.65 mm) for the patient data. Conclusions: The authors introduced a novel method of estimating volumetric time-varying images from single cine EPID images and a PCA-based lung motion model. This is the first method to estimate volumetric time-varying images from single MV cine EPID images, and has the potential to provide volumetric information with no additional imaging dose to the patient.« less

Nonlinear damage identification of breathing cracks in Truss system

NASA Astrophysics Data System (ADS)

Zhao, Jie; DeSmidt, Hans

2014-03-01

The breathing cracks in truss system are detected by Frequency Response Function (FRF) based damage identification method. This method utilizes damage-induced changes of frequency response functions to estimate the severity and location of structural damage. This approach enables the possibility of arbitrary interrogation frequency and multiple inputs/outputs which greatly enrich the dataset for damage identification. The dynamical model of truss system is built using the finite element method and the crack model is based on fracture mechanics. Since the crack is driven by tensional and compressive forces of truss member, only one damage parameter is needed to represent the stiffness reduction of each truss member. Assuming that the crack constantly breathes with the exciting frequency, the linear damage detection algorithm is developed in frequency/time domain using Least Square and Newton Raphson methods. Then, the dynamic response of the truss system with breathing cracks is simulated in the time domain and meanwhile the crack breathing status for each member is determined by the feedback from real-time displacements of member's nodes. Harmonic Fourier Coefficients (HFCs) of dynamical response are computed by processing the data through convolution and moving average filters. Finally, the results show the effectiveness of linear damage detection algorithm in identifying the nonlinear breathing cracks using different combinations of HFCs and sensors.

Breath volatile organic compounds for the gut-fatty liver axis: Promise, peril, and path forward

PubMed Central

Solga, Steven Francis

2014-01-01

The worldwide interest in the gut microbiome and its impact on the upstream liver highlight a critical upside to breath research: it can uniquely measure otherwise unmeasurable biology. Bacteria make gases [volatile organic compounds (VOCs)] that are directly relevant to pathophysiology of the fatty liver and associated conditions, including obesity. Measurement of these VOCs and their metabolites in the exhaled breath, therefore, present an opportunity to safely and easily evaluate, on both a personal and a population level, some of our most pressing public health threats. This is an opportunity that must be pursued. To date, however, breath analysis remains a slowly evolving field which only occasionally impacts clinical research or patient care. One major obstacle to progress is that breath analysis is inherently and emphatically mutli-disciplinary: it connects engineering, chemistry, breath mechanics, biology and medicine. Unbalanced or incomplete teams may produce inconsistent and often unsatisfactory results. A second impediment is the lack of a well-known stepwise structure for the development of non-invasive diagnostics. As a result, the breath research landscape is replete with orphaned single-center pilot studies. Often, important hypotheses and key observations have not been pursued to maturation. This paper reviews the rationale and requirements for breath VOC research applied to the gut-fatty liver axis and offers some suggestions for future development. PMID:25083075

Does taking endurance into account improve the prediction of weaning outcome in mechanically ventilated children?

PubMed Central

Noizet, Odile; Leclerc, Francis; Sadik, Ahmed; Grandbastien, Bruno; Riou, Yvon; Dorkenoo, Aimée; Fourier, Catherine; Cremer, Robin; Leteurtre, Stephane

2005-01-01

Introduction We conducted the present study to determine whether a combination of the mechanical ventilation weaning predictors proposed by the collective Task Force of the American College of Chest Physicians (TF) and weaning endurance indices enhance prediction of weaning success. Method Conducted in a tertiary paediatric intensive care unit at a university hospital, this prospective study included 54 children receiving mechanical ventilation (≥6 hours) who underwent 57 episodes of weaning. We calculated the indices proposed by the TF (spontaneous respiratory rate, paediatric rapid shallow breathing, rapid shallow breathing occlusion pressure [ROP] and maximal inspiratory pressure during an occlusion test [Pimax]) and weaning endurance indices (pressure-time index, tension-time index obtained from P0.1 [TTI1] and from airway pressure [TTI2]) during spontaneous breathing. Performances of each TF index and combinations of them were calculated, and the best single index and combination were identified. Weaning endurance parameters (TTI1 and TTI2) were calculated and the best index was determined using a logistic regression model. Regression coefficients were estimated using the maximum likelihood ratio (LR) method. Hosmer–Lemeshow test was used to estimate goodness-of-fit of the model. An equation was constructed to predict weaning success. Finally, we calculated the performances of combinations of best TF indices and best endurance index. Results The best single TF index was ROP, the best TF combination was represented by the expression (0.66 × ROP) + (0.34 × Pimax), and the best endurance index was the TTI2, although their performance was poor. The best model resulting from the combination of these indices was defined by the following expression: (0.6 × ROP) – (0.1 × Pimax) + (0.5 × TTI2). This integrated index was a good weaning predictor (P < 0.01), with a LR+ of 6.4 and LR+/LR- ratio of 12.5. However, at a threshold value <1.3 it was only predictive of weaning success (LR- = 0.5). Conclusion The proposed combined index, incorporating endurance, was of modest value in predicting weaning outcome. This is the first report of the value of endurance parameters in predicting weaning success in children. Currently, clinical judgement associated with spontaneous breathing trials apparently remain superior. PMID:16356229

Diagnostic Chemical Analysis of Exhaled Human Breath Using a Novel Sub-Millimeter Spectroscopic Approach

NASA Astrophysics Data System (ADS)

Fosnight, Alyssa M.; Moran, Benjamin L.; Branco, Daniela R.; Thomas, Jessica R.; Medvedev, Ivan R.

2013-06-01

As many as 3000 chemicals are reported to be found in exhaled human breath. Many of these chemicals are linked to certain health conditions and environmental exposures. Present state of the art techniques used for analysis of exhaled human breath include mass spectrometry based methods, infrared spectroscopic sensors, electro chemical sensors and semiconductor oxide based testers. Some of these techniques are commercially available but are somewhat limited in their specificity and exhibit fairly high probability of false alarm. Here, we present the results of our most recent study which demonstrated a novel application of a terahertz high resolutions spectroscopic technique to the analysis of exhaled human breath, focused on detection of ethanol in the exhaled breath of a person which consumed an alcoholic drink. This technique possesses nearly ``absolute'' specificity and we demonstrated its ability to uniquely identify ethanol, methanol, and acetone in human breath. This project is now complete and we are looking to extend this method of chemical analysis of exhaled human breath to a broader range of chemicals in an attempt to demonstrate its potential for biomedical diagnostic purposes.

A novel CT acquisition and analysis technique for breathing motion modeling

NASA Astrophysics Data System (ADS)

Low, Daniel A.; White, Benjamin M.; Lee, Percy P.; Thomas, David H.; Gaudio, Sergio; Jani, Shyam S.; Wu, Xiao; Lamb, James M.

2013-06-01

To report on a novel technique for providing artifact-free quantitative four-dimensional computed tomography (4DCT) image datasets for breathing motion modeling. Commercial clinical 4DCT methods have difficulty managing irregular breathing. The resulting images contain motion-induced artifacts that can distort structures and inaccurately characterize breathing motion. We have developed a novel scanning and analysis method for motion-correlated CT that utilizes standard repeated fast helical acquisitions, a simultaneous breathing surrogate measurement, deformable image registration, and a published breathing motion model. The motion model differs from the CT-measured motion by an average of 0.65 mm, indicating the precision of the motion model. The integral of the divergence of one of the motion model parameters is predicted to be a constant 1.11 and is found in this case to be 1.09, indicating the accuracy of the motion model. The proposed technique shows promise for providing motion-artifact free images at user-selected breathing phases, accurate Hounsfield units, and noise characteristics similar to non-4D CT techniques, at a patient dose similar to or less than current 4DCT techniques.

Reaction time following yoga bellows-type breathing and breath awareness.

PubMed

Telles, Shirley; Yadav, Arti; Gupta, Ram Kumar; Balkrishna, Acharya

2013-08-01

The reaction time (RT) was assessed in two groups of healthy males, yoga group (M age = 29.0 yr.) and non-yoga or control group (M age = 29.0 yr.), with 35 participants each. The yoga group had an average experience of 6 months, while the control group was yoga-naïve. The yoga group was assessed in two sessions, (i) bhastrika pranayama or bellows breathing and (ii) breath awareness, while the control group had a single control session. The two experimental sessions, one with each type of breathing, and the control session consisted of pre- (5 min.), during (18 min.), and post-session epochs (5 min.). Assessments were made in the pre- and post-session epochs using a Multi-Operational Apparatus for Reaction Time. Following 18 min. of bhastrika pranayama there was a statistically significant reduction in number of anticipatory responses compared to before the practice. This suggests that the immediate effect of bhastrika pranayama is to inhibit unnecessary responding to stimuli.

Spirometry, Static Lung Volumes, and Diffusing Capacity.

PubMed

Vaz Fragoso, Carlos A; Cain, Hilary C; Casaburi, Richard; Lee, Patty J; Iannone, Lynne; Leo-Summers, Linda S; Van Ness, Peter H

2017-09-01

Spirometric Z-scores from the Global Lung Initiative (GLI) rigorously account for age-related changes in lung function and are thus age-appropriate when establishing spirometric impairments, including a restrictive pattern and air-flow obstruction. However, GLI-defined spirometric impairments have not yet been evaluated regarding associations with static lung volumes (total lung capacity [TLC], functional residual capacity [FRC], and residual volume [RV]) and gas exchange (diffusing capacity). We performed a retrospective review of pulmonary function tests in subjects ≥40 y old (mean age 64.6 y), including pre-bronchodilator measures for: spirometry ( n = 2,586), static lung volumes by helium dilution with inspiratory capacity maneuver ( n = 2,586), and hemoglobin-adjusted single-breath diffusing capacity ( n = 2,508). Using multivariable linear regression, adjusted least-squares means (adj LS Means) were calculated for TLC, FRC, RV, and hemoglobin-adjusted single-breath diffusing capacity. The adj LS Means were expressed with and without height-cubed standardization and stratified by GLI-defined spirometry, including normal ( n = 1,251), restrictive pattern ( n = 663), and air-flow obstruction (mild, [ n = 128]; moderate, [ n = 150]; and severe, [ n = 394]). Relative to normal spirometry, restrictive-pattern had lower adj LS Means for TLC, FRC, RV, and hemoglobin-adjusted single-breath diffusing capacity ( P ≤ .001). Conversely, relative to normal spirometry, mild, moderate, and severe air-flow obstruction had higher adj LS Means for FRC and RV ( P < .001). However, only mild and moderate air-flow obstruction had higher adj LS Means for TLC ( P < .001), while only moderate and severe air-flow obstruction had higher adj LS Means for RV/TLC ( P < .001) and lower adj LS Means for hemoglobin-adjusted single-breath diffusing capacity ( P < .001). Notably, TLC (calculated as FRC + inspiratory capacity) was not increased in severe air-flow obstruction ( P ≥ .11) because inspiratory capacity decreased with increasing air-flow obstruction ( P < .001), thus opposing the increased FRC ( P < .001). Finally, P values were similar whether adj LS Means were height-cubed standardized. A GLI-defined spirometric restrictive pattern is strongly associated with a restrictive ventilatory defect (decreased TLC, FRC, and RV), while GLI-defined spirometric air-flow obstruction is strongly associated with hyperinflation (increased FRC) and air trapping (increased RV and RV/TLC). Both spirometric impairments were strongly associated with impaired gas exchange (decreased hemoglobin-adjusted single-breath diffusing capacity). Copyright © 2017 by Daedalus Enterprises.

Paced respiration with end-expiration technique offers superior BOLD signal repeatability for breath-hold studies.

PubMed

Scouten, A; Schwarzbauer, C

2008-11-01

As a simple, non-invasive method of blood oxygenation level-dependent (BOLD) signal calibration, the breath-hold task offers considerable potential for the quantification of neuronal activity from functional magnetic resonance imaging (fMRI) measurements. With an aim to improve the precision of this calibration method, the impact of respiratory rate control on the BOLD signal achieved with the breath-hold task was investigated. In addition to self-paced breathing, three different computer-paced breathing rates were imposed during the periods between end-expiration breath-hold blocks. The resulting BOLD signal timecourses and statistical activation maps were compared in eleven healthy human subjects. Results indicate that computer-paced respiration produces a larger peak BOLD signal increase with breath-hold than self-paced breathing, in addition to lower variability between trials. This is due to the more significant post-breath-hold signal undershoot present in self-paced runs, a characteristic which confounds the definition of baseline and is difficult to accurately model. Interestingly, the specific respiratory rate imposed between breath-hold periods generally does not have a statistically significant impact on the BOLD signal change. This result can be explained by previous reports of humans adjusting their inhalation depth to compensate for changes in rate, with the end-goal of maintaining homeostatic ventilation. The advantage of using end-expiration relative to end-inspiration breath-hold is apparent in view of the high repeatability of the BOLD signal in the present study, which does not suffer from the previously reported high variability associated with uncontrolled inspiration depth when using the end-inspiration technique.

SU-E-J-160: 4D Dynamic Arc of Non-Modulated Variable-Dose-Rate Fields for Lung SBRT: A Feasibility Study.

PubMed

Yi, B; Yang, X; Niu, Y; Yu, C

2012-06-01

Conformal SBRT plans for Lung cancer with static gantry angles are ideal candidates for applying motion tracking because of: (1) better dosimetric conformity with reduced target margin and (2) easier and more faithful target tracking without intensity modulation. This work is to demonstrate that by delivering the target tracking during gantry rotation, we can significantly improve delivery efficiency without negatively affecting plan quality. A lung SBRT plan with static beams was created using CT images of the reference breathing phase. It is converted to an arc plan with variable dose rate followed by the conversion to a 4D plan with the segment aperture morphing (SAM) method (Gui 2010) with considerations of both target location and shape changes as depicted by the 4D CT. Gantry angle ranges were determined from the clinical monitor units, with the 22.2 MU/degree, which is chosen to maximize the dose rate. All segments of the dynamic 4D plan were merged into a single arc with variable dose rate. Each segment occupying 1/10 of the breathing period delivers 6.6 MUs at a dose rate of 1000 MU/min. Delivery time was measured and compared to the planned. The dose distributions of the single phase 3D plan and the arc 4D plan showed little difference. The delivered time for the 4D arc plan agreed with the calculated time, and is almost the same as delivering the 3D plan without target tracking. A 12 Gy treatment takes less than 2.5 min. The feasibility of a novel 4D delivery method where a 3D SBRT plan is converted into 4D arc delivery has been demonstrated. In addition to realizing the conventional target tracking benefits, our method further improves delivery efficiency, which is important for maintaining the geometric relationship between the target motion and the breathing surrogate during treatment. This study is supported by NIH_Grant_1R01CA133539-01 A2. © 2012 American Association of Physicists in Medicine.

Effect of Maximal Apnoea Easy-Going and Struggle Phases on Subarachnoid Width and Pial Artery Pulsation in Elite Breath-Hold Divers.

PubMed

Winklewski, Pawel J; Barak, Otto; Madden, Dennis; Gruszecka, Agnieszka; Gruszecki, Marcin; Guminski, Wojciech; Kot, Jacek; Frydrychowski, Andrzej F; Drvis, Ivan; Dujic, Zeljko

2015-01-01

The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of intracranial pressure (ICP), pial artery pulsation (cc-TQ) and cardiac contribution to blood pressure (BP), cerebral blood flow velocity (CBFV) and cc-TQ oscillations throughout the maximal breath hold in elite apnoea divers. Non-invasive assessment of sas-TQ and cc-TQ became possible due to recently developed method based on infrared radiation, called near-infrared transillumination/backscattering sounding (NIR-T/BSS). The experimental group consisted of seven breath-hold divers (six men). During testing, each participant performed a single maximal end-inspiratory breath hold. Apnoea consisted of the easy-going and struggle phases (characterised by involuntary breathing movements (IBMs)). Heart rate (HR) was determined using a standard ECG. BP was assessed using the photoplethysmography method. SaO2 was monitored continuously with pulse oximetry. A pneumatic chest belt was used to register thoracic and abdominal movements. Cerebral blood flow velocity (CBFV) was estimated by a 2-MHz transcranial Doppler ultrasonic probe. sas-TQ and cc-TQ were measured using NIR-T/BSS. Wavelet transform analysis was performed to assess cardiac contribution to BP, CBFV and cc-TQ oscillations. Mean BP and CBFV increased compared to baseline at the end of the easy phase and were further augmented by IBMs. cc-TQ increased compared to baseline at the end of the easy phase and remained stable during the IBMs. HR did not change significantly throughout the apnoea, although a trend toward a decrease during the easy phase and recovery during the IBMs was visible. Amplitudes of BP, CBFV and cc-TQ were augmented. sas-TQ and SaO2 decreased at the easy phase of apnoea and further decreased during the IBMs. Apnoea increases intracranial pressure and pial artery pulsation. Pial artery pulsation seems to be stabilised by the IBMs. Cardiac contribution to BP, CBFV and cc-TQ oscillations does not change throughout the apnoea.

Personal exposure to JP-8 jet fuel vapors and exhaust at air force bases.

PubMed Central

Pleil, J D; Smith, L B; Zelnick, S D

2000-01-01

JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and ground crew personnel during preflight operations and for maintenance personnel performing routine tasks. Personal exposure at an Air Force base occurs through occupational exposure for personnel involved with fuel and aircraft handling and/or through incidental exposure, primarily through inhalation of ambient fuel vapors. Because JP-8 is less volatile than its predecessor fuel (JP-4), contact with liquid fuel on skin and clothing may result in prolonged exposure. The slowly evaporating JP-8 fuel tends to linger on exposed personnel during their interaction with their previously unexposed colleagues. To begin to assess the relative exposures, we made ambient air measurements and used recently developed methods for collecting exhaled breath in special containers. We then analyzed for certain volatile marker compounds for JP-8, as well as for some aromatic hydrocarbons (especially benzene) that are related to long-term health risks. Ambient samples were collected by using compact, battery-operated, personal whole-air samplers that have recently been developed as commercial products; breath samples were collected using our single-breath canister method that uses 1-L canisters fitted with valves and small disposable breathing tubes. We collected breath samples from various groups of Air Force personnel and found a demonstrable JP-8 exposure for all subjects, ranging from slight elevations as compared to a control cohort to > 100 [mutilpe] the control values. This work suggests that further studies should be performed on specific issues to obtain pertinent exposure data. The data can be applied to assessments of health outcomes and to recommendations for changes in the use of personal protective equipment that optimize risk reduction without undue impact on a mission. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:10706522

Systems for Lung Volume Standardization during Static and Dynamic MDCT-based Quantitative Assessment of Pulmonary Structure and Function

PubMed Central

Fuld, Matthew K.; Grout, Randall; Guo, Junfeng; Morgan, John H.; Hoffman, Eric A.

2013-01-01

Rationale and Objectives Multidetector-row Computed Tomography (MDCT) has emerged as a tool for quantitative assessment of parenchymal destruction, air trapping (density metrics) and airway remodeling (metrics relating airway wall and lumen geometry) in chronic obstructive pulmonary disease (COPD) and asthma. Critical to the accuracy and interpretability of these MDCT-derived metrics is the assurance that the lungs are scanned during a breath-hold at a standardized volume. Materials and Methods A computer monitored turbine-based flow meter system was developed to control patient breath-holds and facilitate static imaging at fixed percentages of the vital capacity. Due to calibration challenges with gas density changes during multi-breath xenon-CT an alternative system was required. The design incorporated dual rolling seal pistons. Both systems were tested in a laboratory environment and human subject trials. Results The turbine-based system successfully controlled lung volumes in 32/37 subjects, having a linear relationship for CT measured air volume between repeated scans: for all scans, the mean and confidence interval of the differences (scan1-scan2) was −9 ml (−169, 151); for TLC alone 6 ml (−164, 177); for FRC alone, −23 ml (−172, 126). The dual-piston system successfully controlled lung volume in 31/41 subjects. Study failures related largely to subject non-compliance with verbal instruction and gas leaks around the mouthpiece. Conclusion We demonstrate the successful use of a turbine-based system for static lung volume control and demonstrate its inadequacies for dynamic xenon-CT studies. Implementation of a dual-rolling seal spirometer has been shown to adequately control lung volume for multi-breath wash-in xenon-CT studies. These systems coupled with proper patient coaching provide the tools for the use of CT to quantitate regional lung structure and function. The wash-in xenon-CT method for assessing regional lung function, while not necessarily practical for routine clinical studies, provides for a dynamic protocol against which newly emerging single breath, dual-energy xenon-CT measures can be validated. PMID:22555001

Bioanalysis of underivatized amino acids in non-invasive exhaled breath condensate samples using liquid chromatography coupled with tandem mass spectrometry.

PubMed

Konieczna, Lucyna; Pyszka, Magdalena; Okońska, Magdalena; Niedźwiecki, Maciej; Bączek, Tomasz

2018-03-23

Exhaled breath condensate (EBC) is receiving increased attention as a novel, entirely non-invasive technique for collecting biomarker samples. This increased attention is due to the fact that EBC is simple, effort independent, rapid, can be repeated frequently, and can be performed on young children and patients suffering from a variety of diseases. By having a subject breathe tidally through a cooling system for 15-20 min, a sufficient amount of condensate is collected for analysis of biomarkers in clinical studies. However, bioanalysis of EBC involves an unavoidable sample preparation step due to the low concentration of its components. Thus, there is a need for a new and more sensitive analytical method of assessing EBC samples. While researchers have considered analyses of single and small quantities of amino acids - for example, those connected with leukemia - no one has previously attempted to simultaneously analyze a panel of 23 amino acids. Moreover, the present study is well-justified, as prior studies focusing on single amino acids and leukemia at the moment of diagnosis and during chemotherapy (33 days of treatment) are inconsistent. In the present study, amino acids were separated using an XBridge Amide column (3 mm × 100 mm, 3.5 μm). The mobile phase consisted of 10 mM of ammonium buffer in water with a pH of 3 (Phase A) and 10 mM ammonium buffer in acetonitrile (Phase B) under gradient program elution. The analytes were detected in electrospray positive ionization mode. Under optimal conditions, the proposed method exhibited limits of quantification (LOQ) in the range of 0.05-0.5 ng/mL, and good linearity, with the determination coefficient (R 2 ) falling between 0.9904 and 0.9998. The accuracy in human exhaled breath condensate samples ranged between 93.3-113.3% for the 23 studied amino acids, with intra- and inter-day coefficient of variation (CVs) of 0.13-9.92% and 0.17-10.53%, respectively. To demonstrate the liquid chromatography with hydrophilic interaction with electrospray source coupled to tandem mass spectrometry (LC-HILIC-ESI-MS/MS) method's applicability for biomedical investigations, it was verified and applied to determine amino acids in pediatric patients with leukemia. These tests confirmed that glutamine, arginine, homoarginine, asparagine, histidine, methionine, proline, hydroxyproline, threonine, tyrosine, and valine were present in significantly higher levels in pediatric leukemia patients than in the healthy control group. The developed assay is an attractive alternative to standard analytical methods, because it allows for the non-invasive, fast, sensitive, and reliable analysis of amino acids without derivatization in EBC. Copyright © 2018 Elsevier B.V. All rights reserved.

How Dark Are Radial Breathing Modes in Plasmonic Nanodisks?

PubMed

Schmidt, Franz-Philipp; Losquin, Arthur; Hofer, Ferdinand; Hohenau, Andreas; Krenn, Joachim R; Kociak, Mathieu

2018-03-21

Due to a vanishing dipole moment, radial breathing modes in small flat plasmonic nanoparticles do not couple to light and have to be probed with a near-field source, as in electron energy loss spectroscopy (EELS). With increasing particle size, retardation gives rise to light coupling, enabling probing breathing modes optically or by cathodoluminescence (CL). Here, we investigate single silver nanodisks with diameters of 150-500 nm by EELS and CL in an electron microscope and quantify the EELS/CL ratio, which corresponds to the ratio of full to radiative damping of the breathing mode. For the investigated diameter range, we find the CL signal to increase by about 1 order of magnitude, in agreement with numerical simulations. Due to reciprocity, our findings corroborate former optical experiments and enable a quantitative understanding of the light coupling of dark plasmonic modes.

Breath Analysis in Disease Diagnosis: Methodological Considerations and Applications

PubMed Central

Lourenço, Célia; Turner, Claire

2014-01-01

Breath analysis is a promising field with great potential for non-invasive diagnosis of a number of disease states. Analysis of the concentrations of volatile organic compounds (VOCs) in breath with an acceptable accuracy are assessed by means of using analytical techniques with high sensitivity, accuracy, precision, low response time, and low detection limit, which are desirable characteristics for the detection of VOCs in human breath. “Breath fingerprinting”, indicative of a specific clinical status, relies on the use of multivariate statistics methods with powerful in-built algorithms. The need for standardisation of sample collection and analysis is the main issue concerning breath analysis, blocking the introduction of breath tests into clinical practice. This review describes recent scientific developments in basic research and clinical applications, namely issues concerning sampling and biochemistry, highlighting the diagnostic potential of breath analysis for disease diagnosis. Several considerations that need to be taken into account in breath analysis are documented here, including the growing need for metabolomics to deal with breath profiles. PMID:24957037

Breath analysis in disease diagnosis: methodological considerations and applications.

PubMed

Lourenço, Célia; Turner, Claire

2014-06-20

Breath analysis is a promising field with great potential for non-invasive diagnosis of a number of disease states. Analysis of the concentrations of volatile organic compounds (VOCs) in breath with an acceptable accuracy are assessed by means of using analytical techniques with high sensitivity, accuracy, precision, low response time, and low detection limit, which are desirable characteristics for the detection of VOCs in human breath. "Breath fingerprinting", indicative of a specific clinical status, relies on the use of multivariate statistics methods with powerful in-built algorithms. The need for standardisation of sample collection and analysis is the main issue concerning breath analysis, blocking the introduction of breath tests into clinical practice. This review describes recent scientific developments in basic research and clinical applications, namely issues concerning sampling and biochemistry, highlighting the diagnostic potential of breath analysis for disease diagnosis. Several considerations that need to be taken into account in breath analysis are documented here, including the growing need for metabolomics to deal with breath profiles.

Effect of Time-of-Flight Information on PET/MR Reconstruction Artifacts: Comparison of Free-breathing versus Breath-hold MR-based Attenuation Correction.

PubMed

Delso, Gaspar; Khalighi, Mohammed; Ter Voert, Edwin; Barbosa, Felipe; Sekine, Tetsuro; Hüllner, Martin; Veit-Haibach, Patrick

2017-01-01

Purpose To evaluate the magnitude and anatomic extent of the artifacts introduced on positron emission tomographic (PET)/magnetic resonance (MR) images by respiratory state mismatch in the attenuation map. Materials and Methods The method was tested on 14 patients referred for an oncologic examination who underwent PET/MR imaging. The acquisition included standard PET and MR series for each patient, and an additional attenuation correction series was acquired by using breath hold. PET data were reconstructed with and without time-of-flight (TOF) information, first by using the standard free-breathing attenuation map and then again by using the additional breath-hold map. Two-tailed paired t testing and linear regression with 0 intercept was performed on TOF versus non-TOF and free-breathing versus breath-hold data for all detected lesions. Results Fluorodeoxyglucose-avid lesions were found in eight of the 14 patients included in the study. The uptake differences (maximum standardized uptake values) between PET reconstructions with free-breathing versus breath-hold attenuation ranged, for non-TOF reconstructions, from -18% to 26%. The corresponding TOF reconstructions yielded differences from -15% to 18%. Conclusion TOF information was shown to reduce the artifacts caused at PET/MR by respiratory mismatch between emission and attenuation data. © RSNA, 2016 Online supplemental material is available for this article.

An automated system for pulmonary function testing

NASA Technical Reports Server (NTRS)

Mauldin, D. G.

1974-01-01

An experiment to quantitate pulmonary function was accepted for the space shuttle concept verification test. The single breath maneuver and the nitrogen washout are combined to reduce the test time. Parameters are defined from the forced vital capacity maneuvers. A spirometer measures the breath volume and a magnetic section mass spectrometer provides definition of gas composition. Mass spectrometer and spirometer data are analyzed by a PDP-81 digital computer.

Research Technology

NASA Image and Video Library

2004-04-15

Pictured is an artist's concept of the Rocket Based Combined Cycle (RBCC) launch. The RBCC's overall objective is to provide a technology test bed to investigate critical technologies associated with opperational usage of these engines. The program will focus on near term technologies that can be leveraged to ultimately serve as the near term basis for Two Stage to Orbit (TSTO) air breathing propulsions systems and ultimately a Single Stage To Orbit (SSTO) air breathing propulsion system.

Validation of 13C-acetic acid breath test by measuring effects of loperamide, morphine, mosapride, and itopride on gastric emptying in mice.

PubMed

Matsumoto, Kenjiro; Kimura, Hiroshi; Tashima, Kimihito; Uchida, Masayuki; Horie, Syunji

2008-10-01

Several methods are used to evaluate gastric motility in rodents, but they all have technical limitations. Recent technical developments enable a convenient method to evaluate gastric motility. The (13)C-acetic acid breath test in rodents is a non-invasive and repeatable method that can be used without physical restraints. The present study aimed to validate the (13)C-acetic acid breath test by measuring the effects of loperamide, morphine, mosapride, and itopride on gastric emptying in mice. Loperamide (1-10 mg/kg) and morphine (1.25-10 mg/kg) slowed gastric emptying and decreased the maximum concentration (C(max)) and area under the curve (AUC(90 min)) value in a dose-dependent manner. Mosapride (0.2-5 mg/kg) accelerated gastric emptying and increased C(max) value. Mosapride (20 mg/kg) did not accelerate gastric emptying on the (13)C-breath test. Itopride (30 mg/kg, per os) significantly accelerated gastric emptying compared with the vehicle group. In a comparison with the conventional phenol red test, there was a correlation between the C(max) value of breath test and gastric emptying (%) of phenol red tests in treatment with loperamide or mosapride. These results indicate that the (13)C-acetic acid breath test is an accurate, noninvasive, and simple method for monitoring gastric emptying in mice. This method is useful to assess the effect of drugs and gut function pharmacologically.

Analysis of breath volatile organic compounds as a screening tool for detection of Tuberculosis in cattle

USDA-ARS?s Scientific Manuscript database

• Keywords: bovine tuberculosis; Mycobacterium bovis; breath analysis; volatile organic compound; gas chromatography; mass spectrometry; NaNose • Introduction: This presentation describes two studies exploring the use of breath VOCs to identify Mycobacterium bovis infection in cattle. • Methods: ...

Is breath acetone a biomarker of diabetes? A historical review on breath acetone measurements.

PubMed

Wang, Zhennan; Wang, Chuji

2013-09-01

Since the ancient discovery of the 'sweet odor' in human breath gas, pursuits of the breath analysis-based disease diagnostics have never stopped. Actually, the 'smell' of the breath, as one of three key disease diagnostic techniques, has been used in Eastern-Medicine for more than three thousand years. With advancement of measuring technologies in sensitivity and selectivity, more specific breath gas species have been identified and established as a biomarker of a particular disease. Acetone is one of the breath gases and its concentration in exhaled breath can now be determined with high accuracy using various techniques and methods. With the worldwide prevalence of diabetes that is typically diagnosed through blood testing, human desire to achieve non-blood based diabetic diagnostics and monitoring has never been quenched. Questions, such as is breath acetone a biomarker of diabetes and how is the breath acetone related to the blood glucose (BG) level (the golden criterion currently used in clinic for diabetes diagnostic, monitoring, and management), remain to be answered. A majority of current research efforts in breath acetone measurements and its technology developments focus on addressing the first question. The effort to tackle the second question has begun recently. The earliest breath acetone measurement in clearly defined diabetic patients was reported more than 60 years ago. For more than a half-century, as reviewed in this paper, there have been more than 41 independent studies of breath acetone using various techniques and methods, and more than 3211 human subjects, including 1581 healthy people, 242 Type 1 diabetic patients, 384 Type 2 diabetic patients, 174 unspecified diabetic patients, and 830 non-diabetic patients or healthy subjects who are under various physiological conditions, have been used in the studies. The results of the breath acetone measurements collected in this review support that many conditions might cause changes to breath acetone concentrations; however, the results from the six independent studies using clearly-defined Type 1 and Type 2 diabetic patients unanimously support that an elevated mean breath acetone concentration exists in Type 1 diabetes. Note that there is some overlap between the ranges of breath acetone concentration in individual T1D patients and healthy subjects; this reminds one to be careful when using an acetone breath test on T1D diagnostics. Comparatively, it is too early to draw a general conclusion on the relationship between a breath acetone level and a BG level from the very limited data in the literature.

Intermittent Hypoxia and Stem Cell Implants Preserve Breathing Capacity in a Rodent Model of Amyotrophic Lateral Sclerosis

PubMed Central

Nichols, Nicole L.; Gowing, Genevieve; Satriotomo, Irawan; Nashold, Lisa J.; Dale, Erica A.; Suzuki, Masatoshi; Avalos, Pablo; Mulcrone, Patrick L.; McHugh, Jacalyn

2013-01-01

Rationale: Amyotrophic lateral sclerosis (ALS) is a devastating motor neuron disease causing paralysis and death from respiratory failure. Strategies to preserve and/or restore respiratory function are critical for successful treatment. Although breathing capacity is maintained until late in disease progression in rodent models of familial ALS (SOD1G93A rats and mice), reduced numbers of phrenic motor neurons and decreased phrenic nerve activity are observed. Decreased phrenic motor output suggests imminent respiratory failure. Objectives: To preserve or restore phrenic nerve activity in SOD1G93A rats at disease end stage. Methods: SOD1G93A rats were injected with human neural progenitor cells (hNPCs) bracketing the phrenic motor nucleus before disease onset, or exposed to acute intermittent hypoxia (AIH) at disease end stage. Measurements and Main Results: The capacity to generate phrenic motor output in anesthetized rats at disease end stage was: (1) transiently restored by a single presentation of AIH; and (2) preserved ipsilateral to hNPC transplants made before disease onset. hNPC transplants improved ipsilateral phrenic motor neuron survival. Conclusions: AIH-induced respiratory plasticity and stem cell therapy have complementary translational potential to treat breathing deficits in patients with ALS. PMID:23220913

Risk of Neurological Insult in Competitive Deep Breath-Hold Diving.

PubMed

Tetzlaff, Kay; Schöppenthau, Holger; Schipke, Jochen D

2017-02-01

It has been widely believed that tissue nitrogen uptake from the lungs during breath-hold diving would be insufficient to cause decompression stress in humans. With competitive free diving, however, diving depths have been ever increasing over the past decades. A case is presented of a competitive free-diving athlete who suffered stroke-like symptoms after surfacing from his last dive of a series of 3 deep breath-hold dives. A literature and Web search was performed to screen for similar cases of subjects with serious neurological symptoms after deep breath-hold dives. A previously healthy 31-y-old athlete experienced right-sided motor weakness and difficulty speaking immediately after surfacing from a breathhold dive to a depth of 100 m. He had performed 2 preceding breath-hold dives to that depth with surface intervals of only 15 min. The presentation of symptoms and neuroimaging findings supported a clinical diagnosis of stroke. Three more cases of neurological insults were retrieved by literature and Web search; in all cases the athletes presented with stroke-like symptoms after single breath-hold dives of depths exceeding 100 m. Two of these cases only had a short delay to recompression treatment and completely recovered from the insult. This report highlights the possibility of neurological insult, eg, stroke, due to cerebral arterial gas embolism as a consequence of decompression stress after deep breath-hold dives. Thus, stroke as a clinical presentation of cerebral arterial gas embolism should be considered another risk of extreme breath-hold diving.

Analysis of Exhaled Breath for Disease Detection

NASA Astrophysics Data System (ADS)

Amann, Anton; Miekisch, Wolfram; Schubert, Jochen; Buszewski, Bogusław; Ligor, Tomasz; Jezierski, Tadeusz; Pleil, Joachim; Risby, Terence

2014-06-01

Breath analysis is a young field of research with great clinical potential. As a result of this interest, researchers have developed new analytical techniques that permit real-time analysis of exhaled breath with breath-to-breath resolution in addition to the conventional central laboratory methods using gas chromatography-mass spectrometry. Breath tests are based on endogenously produced volatiles, metabolites of ingested precursors, metabolites produced by bacteria in the gut or the airways, or volatiles appearing after environmental exposure. The composition of exhaled breath may contain valuable information for patients presenting with asthma, renal and liver diseases, lung cancer, chronic obstructive pulmonary disease, inflammatory lung disease, or metabolic disorders. In addition, oxidative stress status may be monitored via volatile products of lipid peroxidation. Measurement of enzyme activity provides phenotypic information important in personalized medicine, whereas breath measurements provide insight into perturbations of the human exposome and can be interpreted as preclinical signals of adverse outcome pathways.

Hydrogen breath test in schoolchildren.

PubMed Central

Douwes, A C; Schaap, C; van der Klei-van Moorsel, J M

1985-01-01

The frequency of negative hydrogen breath tests due to colonic bacterial flora which are unable to produce hydrogen was determined after oral lactulose challenge in 98 healthy Dutch schoolchildren. There was a negative result in 9.2%. The probability of a false normal lactose breath test (1:77) was calculated from these results together with those from a separate group of children with lactose malabsorption (also determined by hydrogen breath test). A study of siblings and mothers of subjects with a negative breath test did not show familial clustering of this condition. Faecal incubation tests with various sugars showed an increase in breath hydrogen greater than 100 parts per million in those with a positive breath test while subjects with a negative breath test also had a negative faecal incubation test. The frequency of a false negative hydrogen breath test was higher than previously reported, but this does not affect the superiority of this method of testing over the conventional blood glucose determination. PMID:4004310

Designing breathalyser technology for the developing world: how a single breath can fight the double disease burden.

PubMed

Krisher, Sarah; Riley, Alison; Mehta, Khanjan

2014-04-01

The meteoric rise in the prevalence of non-communicable diseases, alongside already high rates of infectious diseases, is exacerbating the 'double disease burden' in the developing world. There is a desperate need for affordable, accessible and ruggedized diagnostic tools that detect diseases early and direct patients to the correct channels. Breath analysis, the science of utilizing biomarkers in the breath for diagnostic measures, is growing rapidly, especially for use in clinical diagnostic settings. Breathalyser technologies are improving scientifically, but are not yet ready for productization and dissemination to address healthcare challenges. How does one ensure that these new biomedical devices will be suitable for use in developing communities? This article presents a comprehensive review of breath analysis technologies followed by a discussion on how such devices can be designed to conform with WHO's ASSURED criteria so as to reach and sustain in developing countries where they are needed the most.

How Dark Are Radial Breathing Modes in Plasmonic Nanodisks?

PubMed Central

2017-01-01

Due to a vanishing dipole moment, radial breathing modes in small flat plasmonic nanoparticles do not couple to light and have to be probed with a near-field source, as in electron energy loss spectroscopy (EELS). With increasing particle size, retardation gives rise to light coupling, enabling probing breathing modes optically or by cathodoluminescence (CL). Here, we investigate single silver nanodisks with diameters of 150–500 nm by EELS and CL in an electron microscope and quantify the EELS/CL ratio, which corresponds to the ratio of full to radiative damping of the breathing mode. For the investigated diameter range, we find the CL signal to increase by about 1 order of magnitude, in agreement with numerical simulations. Due to reciprocity, our findings corroborate former optical experiments and enable a quantitative understanding of the light coupling of dark plasmonic modes. PMID:29607350

Time-delayed feedback control of breathing localized structures in a three-component reaction-diffusion system.

PubMed

Gurevich, Svetlana V

2014-10-28

The dynamics of a single breathing localized structure in a three-component reaction-diffusion system subjected to time-delayed feedback is investigated. It is shown that variation of the delay time and the feedback strength can lead either to stabilization of the breathing or to delay-induced periodic or quasi-periodic oscillations of the localized structure. A bifurcation analysis of the system in question is provided and an order parameter equation is derived that describes the dynamics of the localized structure in the vicinity of the Andronov-Hopf bifurcation. With the aid of this equation, the boundaries of the stabilization domains as well as the dependence of the oscillation radius on delay parameters can be explicitly derived, providing a robust mechanism to control the behaviour of the breathing localized structure in a straightforward manner. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

High-resolution diffusion tensor imaging of the human kidneys using a free-breathing, multi-slice, targeted field of view approach

PubMed Central

Chan, Rachel W; Von Deuster, Constantin; Stoeck, Christian T; Harmer, Jack; Punwani, Shonit; Ramachandran, Navin; Kozerke, Sebastian; Atkinson, David

2014-01-01

Fractional anisotropy (FA) obtained by diffusion tensor imaging (DTI) can be used to image the kidneys without any contrast media. FA of the medulla has been shown to correlate with kidney function. It is expected that higher spatial resolution would improve the depiction of small structures within the kidney. However, the achievement of high spatial resolution in renal DTI remains challenging as a result of respiratory motion and susceptibility to diffusion imaging artefacts. In this study, a targeted field of view (TFOV) method was used to obtain high-resolution FA maps and colour-coded diffusion tensor orientations, together with measures of the medullary and cortical FA, in 12 healthy subjects. Subjects were scanned with two implementations (dual and single kidney) of a TFOV DTI method. DTI scans were performed during free breathing with a navigator-triggered sequence. Results showed high consistency in the greyscale FA, colour-coded FA and diffusion tensors across subjects and between dual- and single-kidney scans, which have in-plane voxel sizes of 2 × 2 mm2 and 1.2 × 1.2 mm2, respectively. The ability to acquire multiple contiguous slices allowed the medulla and cortical FA to be quantified over the entire kidney volume. The mean medulla and cortical FA values were 0.38 ± 0.017 and 0.21 ± 0.019, respectively, for the dual-kidney scan, and 0.35 ± 0.032 and 0.20 ± 0.014, respectively, for the single-kidney scan. The mean FA between the medulla and cortex was significantly different (p < 0.001) for both dual- and single-kidney implementations. High-spatial-resolution DTI shows promise for improving the characterization and non-invasive assessment of kidney function. © 2014 The Authors. NMR in Biomedicine published by John Wiley & Sons, Ltd. PMID:25219683

High-resolution diffusion tensor imaging of the human kidneys using a free-breathing, multi-slice, targeted field of view approach.

PubMed

Chan, Rachel W; Von Deuster, Constantin; Stoeck, Christian T; Harmer, Jack; Punwani, Shonit; Ramachandran, Navin; Kozerke, Sebastian; Atkinson, David

2014-11-01

Fractional anisotropy (FA) obtained by diffusion tensor imaging (DTI) can be used to image the kidneys without any contrast media. FA of the medulla has been shown to correlate with kidney function. It is expected that higher spatial resolution would improve the depiction of small structures within the kidney. However, the achievement of high spatial resolution in renal DTI remains challenging as a result of respiratory motion and susceptibility to diffusion imaging artefacts. In this study, a targeted field of view (TFOV) method was used to obtain high-resolution FA maps and colour-coded diffusion tensor orientations, together with measures of the medullary and cortical FA, in 12 healthy subjects. Subjects were scanned with two implementations (dual and single kidney) of a TFOV DTI method. DTI scans were performed during free breathing with a navigator-triggered sequence. Results showed high consistency in the greyscale FA, colour-coded FA and diffusion tensors across subjects and between dual- and single-kidney scans, which have in-plane voxel sizes of 2 × 2 mm(2) and 1.2 × 1.2 mm(2) , respectively. The ability to acquire multiple contiguous slices allowed the medulla and cortical FA to be quantified over the entire kidney volume. The mean medulla and cortical FA values were 0.38 ± 0.017 and 0.21 ± 0.019, respectively, for the dual-kidney scan, and 0.35 ± 0.032 and 0.20 ± 0.014, respectively, for the single-kidney scan. The mean FA between the medulla and cortex was significantly different (p < 0.001) for both dual- and single-kidney implementations. High-spatial-resolution DTI shows promise for improving the characterization and non-invasive assessment of kidney function. © 2014 The Authors. NMR in Biomedicine published by John Wiley & Sons, Ltd.

Rocket Based Combined Cycle (RBCC) Engine

NASA Technical Reports Server (NTRS)

2004-01-01

Pictured is an artist's concept of the Rocket Based Combined Cycle (RBCC) launch. The RBCC's overall objective is to provide a technology test bed to investigate critical technologies associated with opperational usage of these engines. The program will focus on near term technologies that can be leveraged to ultimately serve as the near term basis for Two Stage to Orbit (TSTO) air breathing propulsions systems and ultimately a Single Stage To Orbit (SSTO) air breathing propulsion system.

Toward Anatomical Simulation for Breath Training in Mind/Body Medicine

NASA Astrophysics Data System (ADS)

Sanders, Benjamin; Dilorenzo, Paul; Zordan, Victor; Bakal, Donald

The use of breath in healing is poorly understood by patients and professionals alike. Dysfunctional breathing is a characteristic of many unexplained symptoms and mind/body medical professionals seek methods for breath training to alleviate such problems. Our approach is to re-purpose and evolve a recently developed anatomically inspired respiration simulation which was created for synthesizing motion in entertainment for the use of visualization in breath training. In mind/body medicine, problems are often created from patients being advised to breathe according to some standard based on pace or volume. However, a breathing pattern that is comfortable and effortless for one person may not have the same benefits for the next person. The breathing rhythm which is most effortless for each person needs to be dynamically identified. To this end, in this chapter, we employ optimization to modify a generic model of respiration to fit the breath patterns of specific individuals. In practice, the corresponding visualization which is specific to individual patients could be used to train proper breath behavior, both by showing specific (abnormal) practice and recommended modification(s).

A selective nanosensor device for exhaled breath analysis.

PubMed

Gouma, P; Prasad, A; Stanacevic, S

2011-09-01

This paper describes a novel concept of a three-nanosensor array microsystem that may potentially serve as a coarse diagnostic tool handheld breath analyzer to provide a first detection device. The specification and performance of a simple metal oxide nanosensor operating between three distinct temperatures are discussed, focusing on the need for a noninvasive blood cholesterol monitor. Interfacing the sensor array to an integrated circuit for electrical readout and temperature control provides a complete microsystem capable of capturing a single exhaled breath and analyzing it with respect to the relative content of isoprene, carbon dioxide and ammonia gas. This inexpensive sensor technology may be used as a personalized medical diagnostics tool in the near future.

Breathing Maneuvers as a Vasoactive Stimulus for Detecting Inducible Myocardial Ischemia – An Experimental Cardiovascular Magnetic Resonance Study

PubMed Central

Fischer, Kady; Guensch, Dominik P; Shie, Nancy; Lebel, Julie; Friedrich, Matthias G

2016-01-01

Background Breathing maneuvers can elicit a similar vascular response as vasodilatory agents like adenosine; yet, their potential diagnostic utility in the presence of coronary artery stenosis is unknown. The objective of the study is to investigate if breathing maneuvers can non-invasively detect inducible ischemia in an experimental animal model when the myocardium is imaged with oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR). Methods and Findings In 11 anesthetised swine with experimentally induced significant stenosis (fractional flow reserve <0.75) of the left anterior descending coronary artery (LAD) and 9 control animals, OS-CMR at 3T was performed during two different breathing maneuvers, a long breath-hold; and a combined maneuver of 60s of hyperventilation followed by a long breath-hold. The resulting change of myocardial oxygenation was compared to the invasive measurements of coronary blood flow, blood gases, and oxygen extraction. In control animals, all breathing maneuvers could significantly alter coronary blood flow as hyperventilation decreased coronary blood flow by 34±23%. A long breath-hold alone led to an increase of 97±88%, while the increase was 346±327% (p<0.001), when the long breath-hold was performed after hyperventilation. In stenosis animals, the coronary blood flow response was attenuated after both hyperventilation and the following breath-hold. This was matched by the observed oxygenation response as breath-holds following hyperventilation consistently yielded a significant difference in the signal of the MRI images between the perfusion territory of the stenosis LAD and remote myocardium. There was no difference between the coronary territories during the other breathing maneuvers or in the control group at any point. Conclusion In an experimental animal model, the response to a combined breathing maneuver of hyperventilation with subsequent breath-holding is blunted in myocardium subject to significant coronary artery stenosis. This maneuver may allow for detecting severe coronary artery stenosis and have a significant clinical potential as a non-pharmacological method for diagnostic testing in patients with suspected coronary artery disease. PMID:27741282

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Swarajit N., E-mail: snghosh@mcw.ed; Zhang Rong; Department of Pharmacology, Harbin Medical University College of Pharmacy, Harbin

Purpose: To find the mitigators of pneumonitis induced by moderate doses of thoracic radiation (10-15 Gy). Methods and Materials: Unanesthetized WAG/RijCmcr female rats received a single dose of X-irradiation (10, 12, or 15 Gy at 1.615 Gy/min) to the thorax. Captopril (an angiotensin-converting enzyme inhibitor) or losartan (an angiotensin receptor blocker) was administered in the drinking water after irradiation. Pulmonary structure and function were assessed after 8 weeks in randomly selected rats by evaluating the breathing rate, ex vivo vascular reactivity, and histopathologic findings. Survival analysis was undertaken on all animals, except those scheduled for death. Results: Survival after amore » dose of 10 Gy to the thorax was not different from that of unirradiated rats for <=1 year. Survival decreased to <50% by 45 weeks after 12 Gy and by 8-9 weeks after 15 Gy. Captopril (17-56mg/kg/d) improved survival and reduced radiation-induced increases in breathing rate, changes in vascular reactivity, and histopathologic evidence of injury. Radiation-induced increases in the breathing rate were prevented even if captopril was started 1 week after irradiation or if it was discontinued after 5 weeks. Losartan, although effective in reducing mortality, was not as efficacious as captopril in mitigating radiation-induced increases in the breathing rate or altered vasoreactivity. Conclusion: In rats, a moderate thoracic radiation dose induced pneumonitis and morbidity. These injuries were mitigated by captopril even when it was begun 1 week after radiation or if discontinued 5 weeks after exposure. Losartan was less effective in protecting against radiation-induced changes in vascular reactivity or tachypnea.« less

The Effect of Vocal Training Methods on Improving Turkish Accent Defects

ERIC Educational Resources Information Center

Aycan, Kivanc; Evren, Gul Fahriye

2016-01-01

Problem Statement: Despite analyses of how vocal training methods can correct or improve Turkish-language accent defects, for most voice educators, the most important methods continue to be breathe management control and correct vocalization exercises. We therefore sought to demonstrate the relationship of song lyrics to breathe control, accent…

Flow in the human upper airway: work of breathing and the compliant soft palate and tongue

NASA Astrophysics Data System (ADS)

Jermy, Mark; Adams, Cletus; Aplin, Jonathan; Buchajczyk, Marcin; van Hove, Sibylle; Kabaliuk, Natalia; Geoghegan, Patrick; Cater, John

2016-11-01

The human upper airway (nasal cavity, pharynx and trachea) filters, heats and humidifies inspired air. Its pressure drop affects the work of breathing (WOB, energy expended to inspire and expire) to a degree which varies from person to person, and which is altered by breathing therapy devices. We report experimental studies using 3D printed models of the upper airway based on CT scans of single individuals (adult and paediatric), and average geometries based on PCA analysis of 150 individuals. Particle Image Velocimetry (PIV), gas concentration and pressure measurements, coupled with CFD simulation. These reveal the details of the washout of CO2 rich exhaled gas, the direction-dependent time-varying pressure drop, and the effect of high-flow nasal therapy (HFNT) on these phenomena. A 1D multi-compartment model is used to estimate the work of breathing. For the first time, soft (compliant) elements have been included in the model airways and show that the assumption of rigid tissue is acceptable for unassisted breathing, but unrealistic for therapy-assisted flows.

Automatic Recognition of Breathing Route During Sleep Using Snoring Sounds

NASA Astrophysics Data System (ADS)

Mikami, Tsuyoshi; Kojima, Yohichiro

This letter classifies snoring sounds into three breathing routes (oral, nasal, and oronasal) with discriminant analysis of the power spectra and k-nearest neighbor method. It is necessary to recognize breathing route during snoring, because oral snoring is a typical symptom of sleep apnea but we cannot know our own breathing and snoring condition during sleep. As a result, about 98.8% classification rate is obtained by using leave-one-out test for performance evaluation.

Pulmonary function of nonsmoking female asbestos workers without radiographic signs of asbestosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, X.R.; Yano, E.; Nonaka, Koichi

Researchers disagree about whether exposure to asbestos causes significant respiratory impairments and airway obstruction in the absence of radiographic asbestosis and smoking. To obtain confirmatory information, the authors examined pulmonary function of 208 nonsmoking female asbestos workers who did not have asbestosis and 136 controls. The authors observed an overall lower single-breath carbon monoxide diffusing capacity in the asbestos workers than in controls. In addition, significant decreases in percentage vital capacity, percentage forced vital capacity, and percentage mean forced expiratory flow during the middle half of the forced vital capacity were evident in the older workers. Logistic regression analysis revealedmore » that asbestos exposure was associated with abnormal single-breath carbon monoxide diffusing capacity, vital capacity, and mean forced expiratory flow during the middle half of the forced vital capacity among the older workers. The age-related decline in vital capacity, forced vital capacity, and mean forced expiratory flow during the middle half of the forced vital capacity was significantly greater in the asbestos workers than the controls. The findings imply that asbestos-exposure per se contributes predominantly to restricted lung volume and reduced single-breath carbon monoxide diffusing capacity. Asbestos may also cause slight airway obstruction, especially in workers who are heavily exposed.« less

Decompression sickness in breath-hold divers: a review.

PubMed

Lemaitre, Frederic; Fahlman, Andreas; Gardette, Bernard; Kohshi, Kiyotaka

2009-12-01

Although it has been generally assumed that the risk of decompression sickness is virtually zero during a single breath-hold dive in humans, repeated dives may result in a cumulative increase in the tissue and blood nitrogen tension. Many species of marine mammals perform extensive foraging bouts with deep and long dives interspersed by a short surface interval, and some human divers regularly perform repeated dives to 30-40 m or a single dive to more than 200 m, all of which may result in nitrogen concentrations that elicit symptoms of decompression sickness. Neurological problems have been reported in humans after single or repeated dives and recent necropsy reports in stranded marine mammals were suggestive of decompression sickness-like symptoms. Modelling attempts have suggested that marine mammals may live permanently with elevated nitrogen concentrations and may be at risk when altering their dive behaviour. In humans, non-pathogenic bubbles have been recorded and symptoms of decompression sickness have been reported after repeated dives to modest depths. The mechanisms implicated in these accidents indicate that repeated breath-hold dives with short surface intervals are factors that predispose to decompression sickness. During deep diving, the effect of pulmonary shunts and/or lung collapse may play a major role in reducing the incidence of decompression sickness in humans and marine mammals.

Pulmonary function in workers exposed to diesel exhausts: the effect of control measures.

PubMed

Ulfvarson, U; Alexandersson, R; Dahlqvist, M; Ekholm, U; Bergström, B

1991-01-01

To assess the protective effect of exhausts pipe filters or respirators on pulmonary function, 15 workers in a tunnel construction site, truck and loading machine drivers, rock workers, and others were studied. The total and respirable dust, combustible matter in respirable dust, carbon monoxide, nitrogen monoxide and nitrogen dioxide were measured for each subject during entire work shifts. The effect of the exposure on the lung function variables was measured by dynamic spirometry, carbon monoxide single breath technique, and nitrogen single breath wash-out. The exhaust pipe filtering had a protective effect, directly discernible in the drivers on vital capacity and FEV1.0 and for the whole group on FEV% and TLco. The dust respirators had no effect, probably because of the difficulties in correctly using personal protection under the circumstances in the tunnel. In the absence of a true exposure assessment, control measures for diesel exhausts can be tested by medical effect studies. Catalytic particle filters of diesel exhausts are one method of rendering the emissions less irritant, although they will not remove irritant gases. An indicator of diesel exhaust exposure should include the particle fraction of the diesel exhausts, but a discrimination between different sources of organic dust must be possible.

Optimization of PROPELLER reconstruction for free-breathing T1-weighted cardiac imaging.

PubMed

Huang, Teng-Yi; Tseng, Yu-Shen; Tang, Yu-Wei; Lin, Yi-Ru

2012-08-01

Clinical cardiac MR imaging techniques generally require patients to hold their breath during the scanning process to minimize respiratory motion-related artifacts. However, some patients cannot hold their breath because of illness or limited breath-hold capacity. This study aims to optimize the PROPELLER reconstruction for free-breathing myocardial T1-weighted imaging. Eight healthy volunteers (8 men; mean age 26.4 years) participated in this study after providing institutionally approved consent. The PROPELLER encoding method can reconstruct a low-resolution image from every blade because of k-space center oversampling. This study investigated the feasibility of extracting a respiratory trace from the PROPELLER blades by implementing a fully automatic region of interest selection and introducing a best template index to account for the property of the human respiration cycle. Results demonstrated that the proposed algorithm significantly improves the contrast-to-noise ratio and the image sharpness (p < 0.05). The PROPELLER method is expected to provide a robust tool for clinical application in free-breathing myocardial T1-weighted imaging. It could greatly facilitate the acquisition procedures during such a routine examination.

Four-dimensional dose distributions of step-and-shoot IMRT delivered with real-time tumor tracking for patients with irregular breathing: Constant dose rate vs dose rate regulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang Xiaocheng; Han-Oh, Sarah; Gui Minzhi

2012-09-15

Purpose: Dose-rate-regulated tracking (DRRT) is a tumor tracking strategy that programs the MLC to track the tumor under regular breathing and adapts to breathing irregularities during delivery using dose rate regulation. Constant-dose-rate tracking (CDRT) is a strategy that dynamically repositions the beam to account for intrafractional 3D target motion according to real-time information of target location obtained from an independent position monitoring system. The purpose of this study is to illustrate the differences in the effectiveness and delivery accuracy between these two tracking methods in the presence of breathing irregularities. Methods: Step-and-shoot IMRT plans optimized at a reference phase weremore » extended to remaining phases to generate 10-phased 4D-IMRT plans using segment aperture morphing (SAM) algorithm, where both tumor displacement and deformation were considered. A SAM-based 4D plan has been demonstrated to provide better plan quality than plans not considering target deformation. However, delivering such a plan requires preprogramming of the MLC aperture sequence. Deliveries of the 4D plans using DRRT and CDRT tracking approaches were simulated assuming the breathing period is either shorter or longer than the planning day, for 4 IMRT cases: two lung and two pancreatic cases with maximum GTV centroid motion greater than 1 cm were selected. In DRRT, dose rate was regulated to speed up or slow down delivery as needed such that each planned segment is delivered at the planned breathing phase. In CDRT, MLC is separately controlled to follow the tumor motion, but dose rate was kept constant. In addition to breathing period change, effect of breathing amplitude variation on target and critical tissue dose distribution is also evaluated. Results: Delivery of preprogrammed 4D plans by the CDRT method resulted in an average of 5% increase in target dose and noticeable increase in organs at risk (OAR) dose when patient breathing is either 10% faster or slower than the planning day. In contrast, DRRT method showed less than 1% reduction in target dose and no noticeable change in OAR dose under the same breathing period irregularities. When {+-}20% variation of target motion amplitude was present as breathing irregularity, the two delivery methods show compatible plan quality if the dose distribution of CDRT delivery is renormalized. Conclusions: Delivery of 4D-IMRT treatment plans, stemmed from 3D step-and-shoot IMRT and preprogrammed using SAM algorithm, is simulated for two dynamic MLC-based real-time tumor tracking strategies: with and without dose-rate regulation. Comparison of cumulative dose distribution indicates that the preprogrammed 4D plan is more accurately and efficiently conformed using the DRRT strategy, as it compensates the interplay between patient breathing irregularity and tracking delivery without compromising the segment-weight modulation.« less

Gated CT imaging using a free-breathing respiration signal from flow-volume spirometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

D'Souza, Warren D.; Kwok, Young; Deyoung, Chad

2005-12-15

Respiration-induced tumor motion is known to cause artifacts on free-breathing spiral CT images used in treatment planning. This leads to inaccurate delineation of target volumes on planning CT images. Flow-volume spirometry has been used previously for breath-holds during CT scans and radiation treatments using the active breathing control (ABC) system. We have developed a prototype by extending the flow-volume spirometer device to obtain gated CT scans using a PQ 5000 single-slice CT scanner. To test our prototype, we designed motion phantoms to compare image quality obtained with and without gated CT scan acquisition. Spiral and axial (nongated and gated) CTmore » scans were obtained of phantoms with motion periods of 3-5 s and amplitudes of 0.5-2 cm. Errors observed in the volume estimate of these structures were as much as 30% with moving phantoms during CT simulation. Application of motion-gated CT with active breathing control reduced these errors to within 5%. Motion-gated CT was then implemented in patients and the results are presented for two clinical cases: lung and abdomen. In each case, gated scans were acquired at end-inhalation, end-exhalation in addition to a conventional free-breathing (nongated) scan. The gated CT scans revealed reduced artifacts compared with the conventional free-breathing scan. Differences of up to 20% in the volume of the structures were observed between gated and free-breathing scans. A comparison of the overlap of structures between the gated and free-breathing scans revealed misalignment of the structures. These results demonstrate the ability of flow-volume spirometry to reduce errors in target volumes via gating during CT imaging.« less

An accurate method to quantify breathing-induced prostate motion for patients implanted with electromagnetic transponders.

PubMed

Giandini, Tommaso; Panaino, Costanza M V; Avuzzi, Barbara; Morlino, Sara; Villa, Sergio; Bedini, Nice; Carabelli, Gabriele; Frasca, Sarah C; Romanyukha, Anna; Rosenfeld, Anatoly; Pignoli, Emanuele; Valdagni, Riccardo; Carrara, Mauro

2017-03-24

To validate and apply a method for the quantification of breathing-induced prostate motion (BIPM) for patients treated with radiotherapy and implanted with electromagnetic transponders for prostate localization and tracking. For the analysis of electromagnetic transponder signal, dedicated software was developed and validated with a programmable breathing simulator phantom. The software was then applied to 1,132 radiotherapy fractions of 30 patients treated in supine position, and to a further 61 fractions of 2 patients treated in prone position. Application of the software in phantom demonstrated reliability of the developed method in determining simulated breathing frequencies and amplitudes. For supine patients, the in vivo analysis of BIPM resulted in median (maximum) amplitudes of 0.10 mm (0.35 mm), 0.24 mm (0.66 mm), and 0.17 mm (0.61 mm) in the left-right (LR), cranio-caudal (CC), and anterior-posterior (AP) directions, respectively. Breathing frequency ranged between 7.73 and 29.43 breaths per minute. For prone patients, the ranges of the BIPM amplitudes were 0.1-0.5 mm, 0.5-1.3 mm, and 0.7-1.7 mm in the LR, CC, and AP directions, respectively. The developed method was able to detect the BIPM with sub-millimeter accuracy. While for patients treated in supine position the BIPM represents a reduced source of treatment uncertainty, for patients treated in prone position, it can be higher than 3 mm.

Performance of an exhaled nitric oxide and carbon dioxide sensor using quantum cascade laser-based integrated cavity output spectroscopy.

PubMed

McCurdy, Matthew R; Bakhirkin, Yury; Wysocki, Gerard; Tittel, Frank K

2007-01-01

Exhaled nitric oxide (NO) is an important biomarker in asthma and other respiratory disorders. The optical performance of a NOCO(2) sensor employing integrated cavity output spectroscopy (ICOS) with a quantum cascade laser operating at 5.22 microm capable of real-time NO and CO(2) measurements in a single breath cycle is reported. A NO noise-equivalent concentration of 0.4 ppb within a 1-sec integration time is achieved. The off-axis ICOS sensor performance is compared to a chemiluminescent NO analyzer and a nondispersive infrared (NDIR) CO(2) absorption capnograph. Differences between the gas analyzers are assessed by the Bland-Altman method to estimate the expected variability between the gas sensors. The off-axis ICOS sensor measurements are in good agreement with the data acquired with the two commercial gas analyzers. This work demonstrates the performance characteristics and merits of mid-infrared spectroscopy for exhaled breath analysis.

MEASUREMENT OF VOLATILE ORGANIC COMPOUNDS IN EXHALED BREATH AS COLLECTED IN EVACUATED ELECTROPOLISHED CANISTERS

EPA Science Inventory

A set of three complementary analytical methods were developed specifically for exhaled breath as collected in evacuated stainless steel canisters using gas chromatography - mass spectrometry detection. The first is a screening method to quantify the carbon dioxide component (gen...

Determination of breath acetone in 149 type 2 diabetic patients using a ringdown breath-acetone analyzer.

PubMed

Sun, Meixiu; Chen, Zhuying; Gong, Zhiyong; Zhao, Xiaomeng; Jiang, Chenyu; Yuan, Yuan; Wang, Zhennang; Li, Yingxin; Wang, Chuji

2015-02-01

Over 90% of diabetic patients have Type 2 diabetes. Although an elevated mean breath acetone concentration has been found to exist in Type 1 diabetes (T1D), information on breath acetone in Type 2 diabetes (T2D) has yet to be obtained. In this study, we first used gas chromatography-mass spectrometry (GC-MS) to validate a ringdown breath-acetone analyzer based on the cavity-ringdown-spectroscopy technique, through comparing breath acetone concentrations in the range 0.5-2.5 ppm measured using both methods. The linear fitting of R = 0.99 suggests that the acetone concentrations obtained using both methods are consistent with a largest standard deviation of ±0.4 ppm in the lowest concentration of the range. Next, 620 breath samples from 149 T2D patients and 42 healthy subjects were collected and tested using the breath analyzer. Four breath samples were taken from each subject under each of four different conditions: fasting, 2 h post-breakfast, 2 h post-lunch, and 2 h post-dinner. Simultaneous blood glucose levels were also measured using a standard diabetic-management blood-glucose meter. For the 149 T2D subjects, their exhaled breath acetone concentrations ranged from 0.1 to 19.8 ppm; four different ranges of breath acetone concentration, 0.1-19.8, 0.1-7.1, 0.1-6.3, and 0.1-9.5 ppm, were obtained for the subjects under the four different conditions, respectively. For the 42 healthy subjects, their breath acetone concentration ranged from 0.1 to 2.6 ppm; four different ranges of breath acetone concentration, 0.3-2.6, 0.1-2.6, 0.1-1.7, and 0.3-1.6 ppm, were obtained for the four different conditions. The mean breath acetone concentration of the 149 T2D subjects was determined to be 1.5 ± 1.5 ppm, which was 1.5 times that of 1.0 ± 0.6 ppm for the 42 healthy subjects. No correlation was found between the breath acetone concentration and the blood glucose level of the T2D subjects and the healthy volunteers. This study using a relatively large number of subjects provides new data regarding breath acetone in diabetes (T1D and T2D) and suggests that an elevated mean breath acetone concentration also exists in T2D.

News from the Breath Analysis Summit 2011.

PubMed

Corradi, Massimo; Mutti, Antonio

2012-06-01

This special section highlights some of the important work presented at the Breath Analysis Summit 2011, which was held in Parma (Italy) from 11 to 14 September 2011. The meeting, which was jointly organized by the International Association for Breath Research and the University of Parma, was attended by more than 250 delegates from 33 countries, and offered 34 invited lectures and 64 unsolicited scientific contributions. The summit was organized to provide a forum to scientists, engineers and clinicians to present their latest findings and to meet industry executives and entrepreneurs to discuss key trends, future directions and technologies available for breath analysis. A major focus was on nitric oxide, exhaled breath condensate, electronic nose, mass spectrometry and newer sensor technologies. Medical applications ranged from asthma and other respiratory diseases to gastrointestinal disease, occupational diseases, critical care and cancer. Most people identify breath tests with breathalysers used by police to estimate ethanol concentration in blood. However, breath testing has far more sophisticated applications. Breath analysis is rapidly evolving as a new frontier in medical testing for disease states in the lung and beyond. Every individual has a breath fingerprint-or 'breathprint'-that can provide useful information about his or her state of health. This breathprint comprises the many thousands of molecules that are expelled with each breath we exhale. Breath research in the past few years has uncovered the scientific and molecular basis for such clinical observations. Relying on mass spectrometry, we have been able to identify many such unique substances in exhaled breath, including gases, such as nitric oxide (NO) and carbon monoxide (CO), and a wide array of volatile organic compounds. Exhaled breath also carries aerosolized droplets that can be collected as an exhaled breath condensate that contains endogenously produced non-volatile compounds. Breath analysis is now used to diagnose and monitor asthma, check for transplant organ rejection, detect lung cancer and test for Helicobacter pyloriinfection-and the list is growing. A major milestone in the scientific study of breath was marked in the 1970s when Linus Pauling demonstrated that there is more to exhaled breath than the classic gases of nitrogen, oxygen, carbon dioxide and water vapour-a lot more. Based on the gas-liquid partition chromatography analysis, Pauling reported the presence of 250 substances in exhaled breath. We now have the technology to test for any and all of these components. The field of breath analysis has made considerable advances in the 21st century and the utility of breath analysis in health care is advancing quickly. The science is rapidly expanding, the technology is improving and several new applications have been developed or are under commercial development. Breath analysis may rely on both direct (on line) and indirect (off line) reading methods: in the on-line method, breath analysis is immediately available, whereas the use of indirect methods generally involves collecting and trapping the breath sample and subsequently transferring it to an analytical instrument for analysis. Various kinds of breath samples have been used in biological monitoring, including mixed expired air and end expired air: end exhaled air represents the alveolar air concentration and mixed exhaled air represents the gas mixture coming from the dead space of the bronchial tree and the alveolar gas-exchange space. Exhaled breath analysis is an area where the modern day advances in technology and engineering meet the ever expanding need in medicine for more sensitive, specific and non-invasive tests which makes this area a major front in the interface between medicine and engineering. A major breakthrough over the past decade has been the increase in breath-based tests approved by the US Food and Drug Administration (FDA). Devices measuring common breath gases (oxygen, nitrogen, water vapour and CO(2)) in patient respiratory monitoring have served as a platform for technological growth in clinical breath-testing applications. A few exhaled breath tests have demonstrated clinical utility and are in widespread use, and several FDA-approved devices are available. These widely used exhaled breath tests include detection of blood alcohol concentration and exhaled CO(2). Other clinical applications of exhaled breath analysis include testing for H. pylori infection, lactose intolerance, heart transplant rejection and, more recently, monitoring of airway inflammation by means of exhaled NO. Examination of exhaled breath has the potential to change the existing routine approaches in human medicine. The rapidly developing new analytical and computer technologies along with novel, unorthodox ideas are prerequisites for future advances in this field. Scientists who participated in the Breath Analysis Summit 2011 were invited to submit a full length paper to the Journal of Breath Research and this issue includes eight articles which describe the different applications of breath analysis. We thank all the authors for their valuable contribution and we trust that this collection will provide useful information and an update to this rapidly evolving field, giving an example of integration among scientists who address the same topic-breath analysis-from different and complementary perspectives, from basic to clinical research.

Remote Measurements of Heart and Respiration Rates for Telemedicine

PubMed Central

Qian, Yi; Tsien, Joe Z.

2013-01-01

Non-contact and low-cost measurements of heart and respiration rates are highly desirable for telemedicine. Here, we describe a novel technique to extract blood volume pulse and respiratory wave from a single channel images captured by a video camera for both day and night conditions. The principle of our technique is to uncover the temporal dynamics of heart beat and breathing rate through delay-coordinate transformation and independent component analysis-based deconstruction of the single channel images. Our method further achieves robust elimination of false positives via applying ratio-variation probability distributions filtering approaches. Moreover, it enables a much needed low-cost means for preventing sudden infant death syndrome in new born infants and detecting stroke and heart attack in elderly population in home environments. This noncontact-based method can also be applied to a variety of animal model organisms for biomedical research. PMID:24115996

Extraction of RBM frequency of a (10, 0) SWNT using MATLAB

NASA Astrophysics Data System (ADS)

Yadav, Monika; Negi, Sunita

2018-05-01

In the last few decades carbon nanotubes (CNT) have attracted great interest for future applications of these tubes in the field of electronics, composite material and drug delivery etc. The normal modes associated with a carbon nanotube are therefore important to be understood for a better understanding of their behavior. In this paper we report the frequency of the most important "Radial Breathing Mode (RBM)" associated with a single walled carbon nanotube. This is done with the help of a MATLAB program. We observe a RBM frequency associated with a (10, 0) single walled carbon nanotube at 340 cm-1. A very slow frequency component is also observed to be associated with the RBM of the carbon nanotube as reported earlier also. This method used for the extraction of RBM frequency is observed to be simple and fast as compared with the other methods.

Outcome of breath tests in adult patients with suspected small intestinal bacterial overgrowth

PubMed Central

Mattsson, Johanna; Minaya, Maria Teresa; Monegro, Milka; Lebwohl, Benjamin; Lewis, Suzanne K.; Green, Peter HR; Stenberg, Reidun

2017-01-01

Aim: The aim was to investigate breath test outcomes in patients with suspected SIBO and indicative symptoms of SIBO, diagnosed by breath testing. Background: Breath testing is used to detect small intestinal bacterial overgrowth (SIBO) by measuring hydrogen and methane produced by intestinal bacteria. Methods: This retrospective cross sectional study included 311 patients with gastrointestinal symptoms who underwent the breath test for evaluation of SIBO at Celiac Disease Center at Columbia University, New York, in 2014-2015. The patients were divided into two groups based on the physician’s choice: lactulose breath test group (72%) and glucose breath test group (28%). Among them, 38% had a history of celiac disease or non-celiac gluten sensitivity. Results: In total, 46% had a positive breath test: 18% were positive for methane, 24 % positive for hydrogen and 4% positive for both gases (p=0.014). Also, 50% had a positive lactulose breath result and 37% had a positive glucose breath result (p=0.036). The most common symptom for performing the breath test was bloating and the only clinical symptom that significantly showed a positive glucose breath test was increased gas (p=0.028). Conclusion: Lactulose breath test was more often positive than glucose breath test. Positivity for hydrogen was more common than methane. Bloating was the most frequently perceived symptom of the patients undergoing the breath test but the only statistically significant clinical symptom for a positive glucose breath test was increased gas. Furthermore, the results showed that there was no significant association between positive breath test result and gender, age, non-celiac gluten sensitivity or celiac disease. PMID:29118931

Research Technology (ASTP) Rocket Based Combined Cycle (RBCC) Engine

NASA Technical Reports Server (NTRS)

2004-01-01

Pictured is an artist's concept of the Rocket Based Combined Cycle (RBCC) launch. The RBCC's overall objective is to provide a technology test bed to investigate critical technologies associated with opperational usage of these engines. The program will focus on near term technologies that can be leveraged to ultimately serve as the near term basis for Two Stage to Orbit (TSTO) air breathing propulsions systems and ultimately a Single Stage To Orbit (SSTO) air breathing propulsion system.

Oxygen Breathing Accelerates Decompression from Saturation at 40 msw in 70-kg Swine

DTIC Science & Technology

2010-07-01

2010 0 2 AFfER A DEEP SATURATION DIVE-PETERSEN ET AL. REFERENCES 1. Bain SA, Tmg J, Simeonovic CJ, Wilson JO. Technique of venous catheterization ...was catheterized with a 16-gauge by 20.3-cm single lumen catheter (Braun Certofix; B. Braun Medical Inc., Bethlehem, PA) via the modified Seldinger...respiratory distress, as evidenced by open-mouthed, labored breathing, central cyanosis, or the production of frothy white sputum. The onset of se- vere

Real time chemical exposure and risk monitor

DOEpatents

Thrall, Karla D.; Kenny, Donald V.; Endres, George W. R.; Sisk, Daniel R.

1997-01-01

The apparatus of the present invention is a combination of a breath interface and an external exposure dosimeter interface to a chemical analysis device, all controlled by an electronic processor for quantitatively analyzing chemical analysis data from both the breath interface and the external exposure dosimeter for determining internal tissue dose. The method of the present invention is a combination of steps of measuring an external dose, measuring breath content, then analyzing the external dose and breath content and determining internal tissue dose.

Real time chemical exposure and risk monitor

DOEpatents

Thrall, K.D.; Kenny, D.V.; Endres, G.W.R.; Sisk, D.R.

1997-07-08

The apparatus of the present invention is a combination of a breath interface and an external exposure dosimeter interface to a chemical analysis device, all controlled by an electronic processor for quantitatively analyzing chemical analysis data from both the breath interface and the external exposure dosimeter for determining internal tissue dose. The method of the present invention is a combination of steps of measuring an external dose, measuring breath content, then analyzing the external dose and breath content and determining internal tissue dose. 7 figs.

Screening of exhaled breath by low-resolution multicomponent FT-IR spectrometry in patients attending emergency departments.

PubMed

Laakso, Olli; Haapala, Matti; Kuitunen, Tapio; Himberg, Jaakko-Juhani

2004-03-01

Interest in noninvasive methods for disease diagnosis is increasing. In this study, we tested the utility and potential of a portable Fourier transform infrared (FT-IR) multicomponent analyzer in the emergency rooms (ERs) of two Finnish hospitals. Major detected breath volatiles in this population were ethanol, carbon monoxide, methane, and acetone, in addition to carbon dioxide and water. The analysis of breath revealed an ethanol concentration of over 25 ppm (0.1 g/L in blood) in 56 out of 589 patients (9.5%). During nightshifts the proportion was 30% for all and 63% for trauma patients. Five-hundred eighty-four patients had measurable carbon monoxide in their breath. A breath carbon monoxide of over 4 ppm (4.4 micro g/L) differentiated smokers from nonsmokers. Methane over 2 ppm (1.3 micro g/L) was detected in the breath of 32% of the participants. Methane concentration was higher among aged patients. Two-hundred ninety-eight participants had detectable acetone in their breath. Elevated exhaled acetone [10-76 ppm (23-75 micro g/L)] was detected in 10 patients. The FT-IR method proved functional in the ER setting. A major advantage over blood sampling was fast and easy analysis performed by nonlaboratory personnel.

The application of chromatographic breath analysis in the search of volatile biomarkers of chronic kidney disease and coexisting type 2 diabetes mellitus.

PubMed

Grabowska-Polanowska, B; Skowron, M; Miarka, P; Pietrzycka, A; Śliwka, I

2017-08-15

Chromatographic studies on breath composition are aimed at finding volatile markers useful for medical diagnostics or in screening investigations. Studies leading to the development of screening breath tests are especially important for the diagnostics of chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). The aim of the presented study was to confirm diagnostic usefulness of chosen volatile compounds detected in breath, which are suggested as potential biomarkers of renal dysfunction and diabetes. Breath analysis were carried out in three groups: 10 healthy volunteers, 10 patients with CKD and 10 patients with CKD and T2DM. All exhaled air samples were analyzed using gas chromatograph (Agilent 6890GC) coupled with mass spectrometer (5975MSD). Thermal desorption was applied as the enrichment method. TMA was detected only in CKD patients. Higher breath concentrations of methanethiol (MeSH) were observed in CKD patients with coexisting diabetes than in patients with renal dysfunction only or in the healthy group. There was a tendency of increasing MeSH concentration in breath with increasing total glutathione in plasma (r=0.53, p=0.0026). Also, a trend of increasing dimethylsulfide (DMS) levels detected in breath was noticed with an increase of hydrogen sulfide concentration in plasma (r=0.74; p=0.00001) as well as with aspartate aminotransferase (AST), (r=0.61; p=0.001). The presented results suggest the possibility of applying TMA, MeSH, and DMS detection in breath as diagnostic methods. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of Fractional Regional Ventilation Using 4D-CT and Effects of Breathing Maneuvers on Ventilation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mistry, Nilesh N., E-mail: nmistry@som.umaryland.edu; Diwanji, Tejan; Shi, Xiutao

2013-11-15

Purpose: Current implementations of methods based on Hounsfield units to evaluate regional lung ventilation do not directly incorporate tissue-based mass changes that occur over the respiratory cycle. To overcome this, we developed a 4-dimensional computed tomography (4D-CT)-based technique to evaluate fractional regional ventilation (FRV) that uses an individualized ratio of tidal volume to end-expiratory lung volume for each voxel. We further evaluated the effect of different breathing maneuvers on regional ventilation. The results from this work will help elucidate the relationship between global and regional lung function. Methods and Materials: Eight patients underwent 3 sets of 4D-CT scans during 1more » session using free-breathing, audiovisual guidance, and active breathing control. FRV was estimated using a density-based algorithm with mass correction. Internal validation between global and regional ventilation was performed by use of the imaging data collected during the use of active breathing control. The impact of breathing maneuvers on FRV was evaluated comparing the tidal volume from 3 breathing methods. Results: Internal validation through comparison between the global and regional changes in ventilation revealed a strong linear correlation (slope of 1.01, R{sup 2} of 0.97) between the measured global lung volume and the regional lung volume calculated by use of the “mass corrected” FRV. A linear relationship was established between the tidal volume measured with the automated breathing control system and FRV based on 4D-CT imaging. Consistently larger breathing volumes were observed when coached breathing techniques were used. Conclusions: The technique presented improves density-based evaluation of lung ventilation and establishes a link between global and regional lung ventilation volumes. Furthermore, the results obtained are comparable with those of other techniques of functional evaluation such as spirometry and hyperpolarized-gas magnetic resonance imaging. These results were demonstrated on retrospective analysis of patient data, and further research using prospective data is under way to validate this technique against established clinical tests.« less

Vocal warm-up and breathing training for teachers: randomized clinical trial

PubMed Central

Pereira, Lílian Paternostro de Pina; Masson, Maria Lúcia Vaz; Carvalho, Fernando Martins

2015-01-01

OBJECTIVE To compare the effectiveness of two speech therapy interventions, vocal warm-up and breathing training, focusing on teachers’ voice quality. METHODS A single-blind, randomized, parallel clinical trial was conducted. The research included 31 20 to 60-year old teachers from a public school in Salvador, BA, Northeasatern Brazil, with minimum workloads of 20 hours a week, who have or have not reported having vocal alterations. The exclusion criteria were the following: being a smoker, excessive alcohol consumption, receiving additional speech therapy assistance while taking part in the study, being affected by upper respiratory tract infections, professional use of the voice in another activity, neurological disorders, and history of cardiopulmonary pathologies. The subjects were distributed through simple randomization in groups vocal warm-up (n = 14) and breathing training (n = 17). The teachers’ voice quality was subjectively evaluated through the Voice Handicap Index (Índice de Desvantagem Vocal, in the Brazilian version) and computerized voice analysis (average fundamental frequency, jitter, shimmer, noise, and glottal-to-noise excitation ratio) by speech therapists. RESULTS Before the interventions, the groups were similar regarding sociodemographic characteristics, teaching activities, and vocal quality. The variations before and after the intervention in self-assessment and acoustic voice indicators have not significantly differed between the groups. In the comparison between groups before and after the six-week interventions, significant reductions in the Voice Handicap Index of subjects in both groups were observed, as wells as reduced average fundamental frequencies in the vocal warm-up group and increased shimmer in the breathing training group. Subjects from the vocal warm-up group reported speaking more easily and having their voices more improved in a general way as compared to the breathing training group. CONCLUSIONS Both interventions were similar regarding their effects on the teachers’ voice quality. However, each contribution has individually contributed to improve the teachers’ voice quality, especially the vocal warm-up. PMID:26465664

Role of Multimodal Evaluation of Cerebral Hemodynamics in Selecting Patients with Symptomatic Carotid or Middle Cerebral Artery Steno-occlusive Disease for Revascularization

PubMed Central

Sharma, Vijay K; Tsivgoulis, Georgios; Ning, Chou; Teoh, Hock L; Bairaktaris, Chrisostomos; Chong, Vincent FH; Ong, Benjamin KC; Chan, Bernard PL; Sinha, Arvind K

2008-01-01

Background: The circle of Willis provides collateral pathways to perfuse the affected vascular territories in patients with severe stenoocclusive disease of major arteries. The collateral perfusion may become insufficient in certain physiological circumstances due to failed vasodilatory reserve and intracranial steal phenomenon, so-called ‘Reversed-Robinhood syndrome’. We evaluated cerebral hemodynamics and vasodilatory reserve in patients with symptomatic distal internal carotid (ICA) or middle cerebral artery (MCA) severe steno-occlusive disease. Methods: Diagnostic transcranial Doppler (TCD) and TCD-monitoring with voluntary breath-holding according to a standard scanning protocol were performed in patients with severe ICA or MCA steno-occlusive disease. The steal phenomenon was detected as transient, spontaneous, or vasodilatory stimuli-induced velocity reductions in affected arteries at the time of velocity increase in normal vessels. Patients with exhausted vasomotor reactivity and intracranial steal phenomenon during breath-holding were further evaluated by 99technetiumm-hexamethyl propylene amine oxime single photon emission computed tomography (HMPAO-SPECT) with acetazolamide challenge. Results: Sixteen patients (age 27–74 years, 11 men) fulfilled our TCD criteria for exhausted vasomotor reactivity and intracranial steal phenomenon during the standard vasomotor testing by breath holding. Acetazolamide-challenged HMPAO-SPECT demonstrated significant hypoperfusion in 12 patients in affected arterial territories, suggestive of failed vasodilatory reserve. A breath-holding index of ≤0.3 on TCD was associated with an abnormal HMPAO-SPECT with acetazolamide challenge. TCD findings of a breath holding index of ≤0.3 and intracranial steal during the procedure were determinants of a significant abnormality on HMPAO-SPECT with acetazolamide challenge. Conclusion: Multimodal evaluation of cerebral hemodynamics in symptomatic patients with severe steno-occlusive disease of the ICA or MCA is helpful in the identification and quantification of failed vasodilatory reserve. This approach may be useful in selecting patients for possible revascularization procedures. PMID:22518232

Ammonia and ethylene biomarkers in the respiration of the people with schizophrenia using photoacoustic spectroscopy

NASA Astrophysics Data System (ADS)

Popa, Cristina; Petrus, Mioara; Bratu, Ana Maria

2015-05-01

Oxidative stress has become an exciting area of schizophrenia (SCZ) research, and provides ample opportunities and hope for a better understanding of its pathophysiology, which may lead to new treatment strategies. The first objective of the present study was to analyze the oxidative stress markers in breath samples of patients with SCZ before and after the treatment with Levomepromazine. The second objective was to analyze the deficiency of amino acids marker in breath samples of patients with SCZ before and after the treatment. Exhaled breath was collected from 15 SCZ patients and 19 healthy controls; subsequently, CO2 laser photoacoustic spectroscopy was used to assess the exhaled breath compounds of the study subjects. One of the main breath biomarkers of the oxidative stress is ethylene, while one of the main breath biomarkers of the amino acids deficiency is ammonia. The breath biomarkers in the exhalation of SCZ patients exhibited significant differences from the breath biomarkers in the exhalation of healthy controls. Analysis of breath ethylene and breath ammonia provides a related model of SCZ exhalation that could represent an effective and convenient screening method for this intellectual disability.

Clinical applications of breath testing

PubMed Central

Paschke, Kelly M; Mashir, Alquam

2010-01-01

Breath testing has the potential to benefit the medical field as a cost-effective, non-invasive diagnostic tool for diseases of the lung and beyond. With growing evidence of clinical worth, standardization of methods, and new sensor and detection technologies the stage is set for breath testing to gain considerable attention and wider application in upcoming years. PMID:21173863

A Computational Experiment on Single-Walled Carbon Nanotubes

ERIC Educational Resources Information Center

Simpson, Scott; Lonie, David C.; Chen, Jiechen; Zurek, Eva

2013-01-01

A computational experiment that investigates single-walled carbon nanotubes (SWNTs) has been developed and employed in an upper-level undergraduate physical chemistry laboratory course. Computations were carried out to determine the electronic structure, radial breathing modes, and the influence of the nanotube's diameter on the…

SU-C-9A-06: The Impact of CT Image Used for Attenuation Correction in 4D-PET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, Y; Bowsher, J; Yan, S

2014-06-01

Purpose: To evaluate the appropriateness of using 3D non-gated CT image for attenuation correction (AC) in a 4D-PET (gated PET) imaging protocol used in radiotherapy treatment planning simulation. Methods: The 4D-PET imaging protocol in a Siemens PET/CT simulator (Biograph mCT, Siemens Medical Solutions, Hoffman Estates, IL) was evaluated. CIRS Dynamic Thorax Phantom (CIRS Inc., Norfolk, VA) with a moving glass sphere (8 mL) in the middle of its thorax portion was used in the experiments. The glass was filled with {sup 18}F-FDG and was in a longitudinal motion derived from a real patient breathing pattern. Varian RPM system (Varian Medicalmore » Systems, Palo Alto, CA) was used for respiratory gating. Both phase-gating and amplitude-gating methods were tested. The clinical imaging protocol was modified to use three different CT images for AC in 4D-PET reconstruction: first is to use a single-phase CT image to mimic actual clinical protocol (single-CT-PET); second is to use the average intensity projection CT (AveIP-CT) derived from 4D-CT scanning (AveIP-CT-PET); third is to use 4D-CT image to do the phase-matched AC (phase-matching- PET). Maximum SUV (SUVmax) and volume of the moving target (glass sphere) with threshold of 40% SUVmax were calculated for comparison between 4D-PET images derived with different AC methods. Results: The SUVmax varied 7.3%±6.9% over the breathing cycle in single-CT-PET, compared to 2.5%±2.8% in AveIP-CT-PET and 1.3%±1.2% in phasematching PET. The SUVmax in single-CT-PET differed by up to 15% from those in phase-matching-PET. The target volumes measured from single- CT-PET images also presented variations up to 10% among different phases of 4D PET in both phase-gating and amplitude-gating experiments. Conclusion: Attenuation correction using non-gated CT in 4D-PET imaging is not optimal process for quantitative analysis. Clinical 4D-PET imaging protocols should consider phase-matched 4D-CT image if available to achieve better accuracy.« less

A Novel Method to Compute Breathing Volumes via Motion Capture Systems: Design and Experimental Trials.

PubMed

Massaroni, Carlo; Cassetta, Eugenio; Silvestri, Sergio

2017-10-01

Respiratory assessment can be carried out by using motion capture systems. A geometrical model is mandatory in order to compute the breathing volume as a function of time from the markers' trajectories. This study describes a novel model to compute volume changes and calculate respiratory parameters by using a motion capture system. The novel method, ie, prism-based method, computes the volume enclosed within the chest by defining 82 prisms from the 89 markers attached to the subject chest. Volumes computed with this method are compared to spirometry volumes and to volumes computed by a conventional method based on the tetrahedron's decomposition of the chest wall and integrated in a commercial motion capture system. Eight healthy volunteers were enrolled and 30 seconds of quiet breathing data collected from each of them. Results show a better agreement between volumes computed by the prism-based method and the spirometry (discrepancy of 2.23%, R 2  = .94) compared to the agreement between volumes computed by the conventional method and the spirometry (discrepancy of 3.56%, R 2  = .92). The proposed method also showed better performances in the calculation of respiratory parameters. Our findings open up prospects for the further use of the new method in the breathing assessment via motion capture systems.

Multifrequency high precise subTHz-THz-IR spectroscopy for exhaled breath research

NASA Astrophysics Data System (ADS)

Vaks, Vladimir L.; Domracheva, Elena G.; Pripolzin, Sergey I.; Chernyaeva, Mariya B.

2016-09-01

Nowadays the development of analytical spectroscopy with high performance, sensitivity and spectral resolution for exhaled breath research is attended. The method of two-frequency high precise THz spectroscopy and the method of high precise subTHz-THz-IR spectroscopy are presented. Development of a subTHz-THz-IR gas analyzer increases the number of gases that can be identified and the reliability of the detection by confirming the signature in both THz and MIR ranges. The testing measurements have testified this new direction of analytical spectroscopy to open widespread trends of its using for various problems of medicine and biology. First of all, there are laboratory investigations of the processes in exhaled breath and studying of their dynamics. Besides, the methods presented can be applied for detecting intermediate and short time living products of reactions in exhaled breath. The spectrometers have been employed for investigations of acetone, methanol and ethanol in the breath samples of healthy volunteers and diabetes patients. The results have demonstrated an increased concentration of acetone in breath of diabetes patients. The dynamic of changing the acetone concentration before and after taking the medicines is discovered. The potential markers of pre-cancer states and oncological diseases of gastrointestinal tract organs have been detected. The changes in the NO concentration in exhaled breath of cancer patients during radiotherapy as well as increase of the NH3 concentration at gastrointestinal diseases have been revealed. The preliminary investigations of biomarkers in three frequency ranges have demonstrated the advantages of the multifrequency high precise spectroscopy for noninvasive medical diagnostics.

Therapeutic hypertension system based on a microbreathing pressure sensor system.

PubMed

Diao, Ziji; Liu, Hongying; Zhu, Lan; Gao, Xiaoqiang; Zhao, Suwen; Pi, Xitian; Zheng, Xiaolin

2011-01-01

A novel therapeutic system for the treatment of hypertension was developed on the basis of a slow-breath training mechanism, using a microbreathing pressure sensor device for the detection of human respiratory signals attached to the abdomen. The system utilizes a single-chip AT89C51 microcomputer as a core processor, programmed by Microsoft Visual C++6.0 to communicate with a PC via a full-speed PDIUSBD12 interface chip. The programming is based on a slow-breath guided algorithm in which the respiratory signal serves as a physiological feedback parameter. Inhalation and exhalation by the subject is guided by music signals. Our study indicates that this microbreathing sensor system may assist in slow-breath training and may help to decrease blood pressure.

A rapid method for the chromatographic analysis of volatile organic compounds in exhaled breath of tobacco cigarette and electronic cigarette smokers.

PubMed

Marco, Esther; Grimalt, Joan O

2015-09-04

A method for the rapid analysis of volatile organic compounds (VOCs) in smoke from tobacco and electronic cigarettes and in exhaled breath of users of these smoking systems has been developed. Both disposable and rechargeable e-cigarettes were considered. Smoke or breath were collected in Bio-VOCs. VOCs were then desorbed in Tenax cartridges which were subsequently analyzed by thermal desorption coupled to gas chromatography-mass spectrometry. The method provides consistent results when comparing the VOC compositions from cigarette smoke and the equivalent exhaled breath of the smokers. The differences in composition of these two sample types are useful to ascertain which compounds are retained in the respiratory system after tobacco cigarette or e-cigarette smoking. Strong differences were observed in the VOC composition of tobacco cigarette smoke and exhaled breath when comparing with those of e-cigarette smoking. The former involved transfers of a much larger burden of organic compounds into smokers, including benzene, toluene, naphthalene and other pollutants of general concern. e-Cigarettes led to strong absorptions of propylene glycol and glycerin in the users of these systems. Tobacco cigarettes were also those showing highest concentration differences between nicotine concentrations in smoke and exhaled breath. The results from disposable e-cigarettes were very similar to those from rechargeable e-cigarettes. Copyright © 2015 Elsevier B.V. All rights reserved.

A Modified Carbon Monoxide Breath Test for Measuring Erythrocyte Lifespan in Small Animals

PubMed Central

Ma, Yong-Jian; Zhang, Hou-De; Ji, Yong-Qiang; Zhu, Guo-Liang; Huang, Jia-Liang; Du, Li-Tao; Cao, Ping; Zang, De-Yue; Du, Ji-Hui; Li, Rong; Wang, Lei

2016-01-01

This study was to develop a CO breath test for RBC lifespan estimation of small animals. The ribavirin induced hemolysis rabbit models were placed individually in a closed rebreath cage and air samples were collected for measurement of CO concentration. RBC lifespan was calculated from accumulated CO, blood volume, and hemoglobin concentration data. RBC lifespan was determined in the same animals with the standard biotin-labeling method. RBC lifespan data obtained by the CO breath test method for control (CON, 49.0 ± 5.9 d) rabbits, rabbits given 10 mg/kg·d−1 of ribavirin (RIB10, 31.0 ± 4.0 d), and rabbits given 20 mg/kg·d−1 of ribavirin (RIB20, 25.0 ± 2.9 d) were statistically similar (all p > 0.05) to and linearly correlated (r = 0.96, p < 0.01) with the RBC lifespan data obtained for the same rabbits by the standard biotin-labeling method (CON, 51.0 ± 2.7 d; RIB10, 33.0 ± 1.3 d; and RIB20, 27.0 ± 0.8 d). The CO breath test method takes less than 3 h to complete, whereas the standard method requires at least several weeks. In conclusion, the CO breath test method provides a simple and rapid means of estimating RBC lifespan and is feasible for use with small animal models. PMID:27294128

[Renal arterial spin labeling magnetic resonance imaging in normal adults: a study with a 3.0 T scanner].

PubMed

Zhang, Fan; Zhang, Xuelin; Yang, Li; Shen, Jie; Gao, Wei

2013-10-01

To analyze the renal relative blood flow value (rBFV) and image quality in normal adults using single-shot fast spin echo, flow sensitive invention recovery (SSFSE-FAIR) magnetic resonance (MR) sequence and echo planar imaging, and flow sensitive invention recovery (EPI-FAIR) MR sequence, and assess its value for clinical application in routine renal examination. Forty volunteers (25 male and 15 female adults, aged 30 to 62 years) with normal renal function were included in this prospective study. All the subjects underwent 3.0 Tesla MR scanning using 3 MR scan modes, namely breath-holding EPI-FAIR, breath-holding SSFSE-FAIR and free breathing SSFSE-FAIR. SSFSE-FAIR without breath-holding was capable of differentiating the renal cortex and medulla with the corresponding rBFVs of 111.48∓9.23 and 94.98∓3.38, respectively. Breath-holding SSFSE-FAIR and EPI-FAIR failed to distinguish the borders of the renal cortex and medulla. The EPI-FAIR rBFV of mixed cortex and medulla value was 178.50∓17.17 (95%CI: 167.59, 189.41). Breath-holding SSFSE-FAIR and EPI-FAIR can not distinguish the renal cortex and medulla due to a poor spatial resolution but can be used for rough evaluation of renal blood perfusion. Free breathing SSFSE-FAIR with an improved spatial resolution allows evaluation of the status of renal perfusion of the cortex and medulla.

Advances in Fabrication Materials of Honeycomb Structure Films by the Breath-Figure Method

PubMed Central

Heng, Liping; Wang, Bin; Li, Muchen; Zhang, Yuqi; Jiang, Lei

2013-01-01

Creatures in nature possess almost perfect structures and properties, and exhibit harmonization and unification between structure and function. Biomimetics, mimicking nature for engineering solutions, provides a model for the development of functional surfaces with special properties. Recently, honeycomb structure materials have attracted wide attention for both fundamental research and practical applications and have become an increasingly hot research topic. Though progress in the field of breath-figure formation has been reviewed, the advance in the fabrication materials of bio-inspired honeycomb structure films has not been discussed. Here we review the recent progress of honeycomb structure fabrication materials which were prepared by the breath-figure method. The application of breath figures for the generation of all kinds of honeycomb is discussed. PMID:28809319

Active cycle of breathing technique for cystic fibrosis.

PubMed

Mckoy, Naomi A; Wilson, Lisa M; Saldanha, Ian J; Odelola, Olaide A; Robinson, Karen A

2016-07-05

People with cystic fibrosis experience chronic airway infections as a result of mucus build up within the lungs. Repeated infections often cause lung damage and disease. Airway clearance therapies aim to improve mucus clearance, increase sputum production, and improve airway function. The active cycle of breathing technique (also known as ACBT) is an airway clearance method that uses a cycle of techniques to loosen airway secretions including breathing control, thoracic expansion exercises, and the forced expiration technique. This is an update of a previously published review. To compare the clinical effectiveness of the active cycle of breathing technique with other airway clearance therapies in cystic fibrosis. We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Date of last search: 25 April 2016. Randomised or quasi-randomised controlled clinical studies, including cross-over studies, comparing the active cycle of breathing technique with other airway clearance therapies in cystic fibrosis. Two review authors independently screened each article, abstracted data and assessed the risk of bias of each study. Our search identified 62 studies, of which 19 (440 participants) met the inclusion criteria. Five randomised controlled studies (192 participants) were included in the meta-analysis; three were of cross-over design. The 14 remaining studies were cross-over studies with inadequate reports for complete assessment. The study size ranged from seven to 65 participants. The age of the participants ranged from six to 63 years (mean age 22.33 years). In 13 studies, follow up lasted a single day. However, there were two long-term randomised controlled studies with follow up of one to three years. Most of the studies did not report on key quality items, and therefore, have an unclear risk of bias in terms of random sequence generation, allocation concealment, and outcome assessor blinding. Due to the nature of the intervention, none of the studies blinded participants or the personnel applying the interventions. However, most of the studies reported on all planned outcomes, had adequate follow up, assessed compliance, and used an intention-to-treat analysis.Included studies compared the active cycle of breathing technique with autogenic drainage, airway oscillating devices, high frequency chest compression devices, conventional chest physiotherapy, and positive expiratory pressure. Preference of technique varied: more participants preferred autogenic drainage over the active cycle of breathing technique; more preferred the active cycle of breathing technique over airway oscillating devices; and more were comfortable with the active cycle of breathing technique versus high frequency chest compression. No significant difference was seen in quality of life, sputum weight, exercise tolerance, lung function, or oxygen saturation between the active cycle of breathing technique and autogenic drainage or between the active cycle of breathing technique and airway oscillating devices. There was no significant difference in lung function and the number of pulmonary exacerbations between the active cycle of breathing technique alone or in conjunction with conventional chest physiotherapy. All other outcomes were either not measured or had insufficient data for analysis. There is insufficient evidence to support or reject the use of the active cycle of breathing technique over any other airway clearance therapy. Five studies, with data from eight different comparators, found that the active cycle of breathing technique was comparable with other therapies in outcomes such as participant preference, quality of life, exercise tolerance, lung function, sputum weight, oxygen saturation, and number of pulmonary exacerbations. Longer-term studies are needed to more adequately assess the effects of the active cycle of breathing technique on outcomes important for people with cystic fibrosis such as quality of life and preference.

Evolution of clinical and environmental health applications of exhaled breath research: Review of methods and instrumentation for gas-phase, condensate, and aerosols

EPA Science Inventory

Human breath, along with urine and blood, has long been one of the three major biological media for assessing human health and environmental exposure. In fact, the detection of odor on human breath, as described by Hippocrates in 400 BC, is considered the first analytical healt...

Whole left ventricular functional assessment from two minutes free breathing multi-slice CINE acquisition

NASA Astrophysics Data System (ADS)

Usman, M.; Atkinson, D.; Heathfield, E.; Greil, G.; Schaeffter, T.; Prieto, C.

2015-04-01

Two major challenges in cardiovascular MRI are long scan times due to slow MR acquisition and motion artefacts due to respiratory motion. Recently, a Motion Corrected-Compressed Sensing (MC-CS) technique has been proposed for free breathing 2D dynamic cardiac MRI that addresses these challenges by simultaneously accelerating MR acquisition and correcting for any arbitrary motion in a compressed sensing reconstruction. In this work, the MC-CS framework is combined with parallel imaging for further acceleration, and is termed Motion Corrected Sparse SENSE (MC-SS). Validation of the MC-SS framework is demonstrated in eight volunteers and three patients for left ventricular functional assessment and results are compared with the breath-hold acquisitions as reference. A non-significant difference (P > 0.05) was observed in the volumetric functional measurements (end diastolic volume, end systolic volume, ejection fraction) and myocardial border sharpness values obtained with the proposed and gold standard methods. The proposed method achieves whole heart multi-slice coverage in 2 min under free breathing acquisition eliminating the time needed between breath-holds for instructions and recovery. This results in two-fold speed up of the total acquisition time in comparison to the breath-hold acquisition.

SU-E-T-326: The Oxygen Saturation (SO2) and Breath-Holding Time Variation Applied Active Breathing Control (ABC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, G; Yin, Y

Purpose: To study the oxygen saturation (SO2) and breath-holding time variation applied active breathing control (ABC) in radiotherapy of tumor. Methods: 24 volunteers were involved in our trials, and they all did breath-holding motion assisted by ELEKTA Active Breathing Coordinator 2.0 for 10 times respectively. And the patient monitor was used to observe the oxygen saturation (SO2) variation. The variation of SO2, and length of breath-holding time and the time for recovering to the initial value of SO2 were recorded and analyzed. Results: (1) The volunteers were divided into two groups according to the SO2 variation in breath-holding: A group,more » 14 cases whose SO2 reduction were more than 2% (initial value was 97% to 99%, while termination value was 91% to 96%); B group, 10 cases were less than 2% in breath-holding without inhaling oxygen. (2) The interfraction breath holding time varied from 8 to 20s for A group compared to the first breath-holding time, and for B group varied from 4 to 14s. (3) The breathing holding time of B group prolonged mean 8s, compared to A group. (4) The time for restoring to the initial value of SO2 was from 10s to 30s. And the breath-holding time shortened obviously for patients whose SO2 did not recover to normal. Conclusion: It is very obvious that the SO2 reduction in breath-holding associated with ABC for partial people. It is necessary to check the SO2 variation in breath training, and enough time should be given to recover SO2.« less

Assessment of distribution of ventilation by electrical impedance tomography in standing horses.

PubMed

Ambrisko, T D; Schramel, J P; Adler, A; Kutasi, O; Makra, Z; Moens, Y P S

2016-02-01

The aim was to evaluate the feasibility of using electrical impedance tomography (EIT) in horses. Thoracic EIT was used in nine horses. Thoracic and abdominal circumference changes were also measured with respiratory ultrasound plethysmography (RUP). Data were recorded during baseline, rebreathing of CO2 and sedation. Three breaths were selected for analysis from each recording. During baseline breathing, horses regularly took single large breaths (sighs), which were also analysed. Functional EIT images were created using standard deviations (SD) of pixel signals and correlation coefficients (R) of each pixel signal with a reference respiratory signal. Left-to-right ratio, centre-of-ventilation and global-inhomogeneity-index were calculated. RM-ANOVA and Bonferroni tests were used (P < 0.05). Distribution of ventilation shifted towards right during sighs and towards dependent regions during sighs, rebreathing and sedation. Global-inhomogeneity-index did not change for SD but increased for R images during sedation. The sum of SDs for the respiratory EIT signals correlated well with thoracic (r(2) = 0.78) and abdominal (r(2) = 0.82) tidal circumferential changes. Inverse respiratory signals were identified on the images at sternal location and based on reviewing CT images, seemed to correspond to location of gas filled intestines. Application of EIT in standing non-sedated horses is feasible. EIT images may provide physiologically useful information even in situations, such as sighs, that cannot easily be tested by other methods.

Method and apparatus for non-invasive evaluation of diaphragmatic function

NASA Technical Reports Server (NTRS)

Yost, William T. (Inventor); Wait, Juliette L. (Inventor); Nahormek, Patricia A. (Inventor); Cantrell, John H. (Inventor); Hanna-Hawver, Pamela D. (Inventor)

1995-01-01

A method for non-invasive evaluation of diaphragmatic function in humans measures the thickness of the diaphragm in real time with an ultrasonic device, and displays the variations of diaphragm thickness versus time. Formulae are given for calculating a quantitative value for the reserve fatigue capacity of a patient's diaphragm from data obtained by measuring the time limits for maintaining a constant breathing pattern on the display at two different pressure differentials in series with the patient's airways. An apparatus for displaying the diaphragm thickness in real time is also described. The method can be used both on healthy patients and on patients with so severe breathing dysfunctions that they require breathing support from respirators.

Method and apparatus for non-invasive evaluation of diaphragmatic function

NASA Technical Reports Server (NTRS)

Yost, William T. (Inventor); Wait, Juliette L. (Inventor); Nahormek, Patricia A. (Inventor); Cantrell, John H. (Inventor); Hanna-Hawver, Pamela D. (Inventor)

1994-01-01

A method for non-invasive evaluation of diaphragmatic function in humans measures the thickness of the diaphragm in real time with an ultrasonic device, and displays the variations of diaphragm thickness versus time. Formulae are given for calculating a quantitative value for the reserve fatigue capacity of a patient's diaphragm from data obtained by measuring the time limits for maintaining a constant breathing pattern on the display at two different pressure differentials in series with the patient's airways. An apparatus for displaying the diaphragm thickness in real time is also described. The method can be used both on healthy patients and on patients with so severe breathing dysfunctions that they require breathing support from respirators.

Metabolomic analysis of breath volatile organic compounds reveals unique breathprints in children with inflammatory bowel disease: a pilot study.

PubMed

Patel, N; Alkhouri, N; Eng, K; Cikach, F; Mahajan, L; Yan, C; Grove, D; Rome, E S; Lopez, R; Dweik, R A

2014-09-01

Breath testing is becoming an important diagnostic method to evaluate many disease states. In the light of rising healthcare costs, is important to develop a simple non-invasive tool to potentially identify paediatric patients who need endoscopy for suspected inflammatory bowel disease (IBD). To analyse exhaled volatile organic compounds (VOCs) and investigate the presence of a unique breath patterns to differentiate paediatric patients with (IBD) from healthy controls. A cross-sectional, single-centre study included paediatric IBD patients and healthy controls (age range, 5-21 years). The diagnosis of IBD was confirmed by endoscopic, histological and radiographic data. Exhaled breath was collected and analysed using a selective ion flow tube mass spectroscopy (SIFT-MS) to identify new markers or patterns of IBD. One hundred and seventeen patients (62 with IBD and 55 healthy controls) were included in the study. Linear discriminant analysis and principle component analysis of mass scanning ion peak data demonstrated 21 pre-selected VOCs correctly classify patients with IBD or as healthy controls; P < 0.0001. Multivariable logistic regression analysis further showed three specific VOCs (1-octene, 1-decene, (E)-2-nonene) had excellent accuracy for predicting the presence of IBD with an area under the curve (AUC) of 0.96 (95% CI: 0.93-0.99). No significant difference in VOCs was found between patients with Crohn's disease or ulcerative colitis, and no significant correlation was seen with disease activity. These pilot data support the hypothesis that a unique breathprint potentially exists for paediatric IBD in the exhaled metabolome. © 2014 John Wiley & Sons Ltd.

Natural 18O and 13C-urea in gastric juice: a new route for non-invasive detection of ulcers.

PubMed

Maity, Abhijit; Pal, Mithun; Som, Suman; Maithani, Sanchi; Chaudhuri, Sujit; Pradhan, Manik

2017-01-01

The 13 C-urea breath test ( 13 C-UBT), developed a few decades ago, is widely used as a non-invasive diagnostic method to detect only the presence of the gastric pathogen Helicobacter pylori infection; however, the actual disease state, i.e. whether the person harbouring H. pylori has peptic ulcer disease (PUD) or non-ulcerous dyspepsia (NUD), is still poorly understood. Nevertheless, the present 13 C-UBT has numerous limitations, drawbacks and pitfalls owing to the ingestion of 13 C-labelled external urea. Here, we show that H. pylori is able to utilize the natural 13 C and 18 O-urea inherently present in the gastric juice in humans for its urease activity which has never been explored before. In vitro measurements of isotopic fractionations of gastric juice urea provide new insights into the actual state of the infection of PUD or NUD. We also provide evidence of the unusual 13 C and 18 O-isotopic fractionations of breath CO 2 that are distinctively altered in individuals with PUD encompassing both gastric and duodenal ulcers as well as with NUD by the enzymatic activity of H. pylori in the gastric niche without oral administration of any 13 C-enriched external urea. This deepens our understanding of the UBT exploiting the natural 13 C and 18 O-gastric juice urea in the pathogenesis of H. pylori infection, reveals the actual disease state of PUD or NUD and thus offers novel opportunities for a simple, robust, cost-effective and non-toxic global strategy devoid of any 13 C-enriched urea for treating these common diseases by a single breath test. Graphical Abstract Urea breath test without any external urea.

Towards Breath Gas Analysis Based on Millimeter-Wave Molecular Spectroscopy

NASA Astrophysics Data System (ADS)

Rothbart, Nick; Hübers, Heinz-Wilhelm; Schmalz, Klaus; Borngräber, Johannes; Kissinger, Dietmar

2018-03-01

Breath gas analysis is a promising non-invasive tool for medical diagnosis as there are thousands of Volatile Organic Compounds (VOCs) in human breath that can be used as health monitoring markers. Millimeter-wave/terahertz molecular spectroscopy is highly suitable for breath gas analysis due to unique fingerprint spectra of many VOCs in that frequency range. We present our recent work on sensor systems for gas spectroscopy based on integrated transmitters (TX) and receivers (RX) fabricated in IHP's 0.13 μm SiGe BiCMOS technology. For a single-band system, spectroscopic measurements and beam profiles are presented. The frequency is tuned by direct voltage-frequency tuning and by a fractional-n PLL, respectively. The spectroscopic system includes a folded gas absorption cell with gas pre-concentration abilities demonstrating the detection of a 50 ppm mixture of ethanol in ambient air corresponding to a minimum detectable concentration of 260 ppb. Finally, the design of a 3-band system covering frequencies from 225 to 273 GHz is introduced.

Pore Breathing of Metal-Organic Frameworks by Environmental Transmission Electron Microscopy.

PubMed

Parent, Lucas R; Pham, C Huy; Patterson, Joseph P; Denny, Michael S; Cohen, Seth M; Gianneschi, Nathan C; Paesani, Francesco

2017-10-11

Metal-organic frameworks (MOFs) have emerged as a versatile platform for the rational design of multifunctional materials, combining large specific surface areas with flexible, periodic frameworks that can undergo reversible structural transitions, or "breathing", upon temperature and pressure changes, and through gas adsorption/desorption processes. Although MOF breathing can be inferred from the analysis of adsorption isotherms, direct observation of the structural transitions has been lacking, and the underlying processes of framework reorganization in individual MOF nanocrystals is largely unknown. In this study, we describe the characterization and elucidation of these processes through the combination of in situ environmental transmission electron microscopy (ETEM) and computer simulations. This combined approach enables the direct monitoring of the breathing behavior of individual MIL-53(Cr) nanocrystals upon reversible water adsorption and temperature changes. The ability to characterize structural changes in single nanocrystals and extract lattice level information through in silico correlation provides fundamental insights into the relationship between pore size/shape and host-guest interactions.

Effects of ion channel noise on neural circuits: an application to the respiratory pattern generator to investigate breathing variability.

PubMed

Yu, Haitao; Dhingra, Rishi R; Dick, Thomas E; Galán, Roberto F

2017-01-01

Neural activity generally displays irregular firing patterns even in circuits with apparently regular outputs, such as motor pattern generators, in which the output frequency fluctuates randomly around a mean value. This "circuit noise" is inherited from the random firing of single neurons, which emerges from stochastic ion channel gating (channel noise), spontaneous neurotransmitter release, and its diffusion and binding to synaptic receptors. Here we demonstrate how to expand conductance-based network models that are originally deterministic to include realistic, physiological noise, focusing on stochastic ion channel gating. We illustrate this procedure with a well-established conductance-based model of the respiratory pattern generator, which allows us to investigate how channel noise affects neural dynamics at the circuit level and, in particular, to understand the relationship between the respiratory pattern and its breath-to-breath variability. We show that as the channel number increases, the duration of inspiration and expiration varies, and so does the coefficient of variation of the breath-to-breath interval, which attains a minimum when the mean duration of expiration slightly exceeds that of inspiration. For small channel numbers, the variability of the expiratory phase dominates over that of the inspiratory phase, and vice versa for large channel numbers. Among the four different cell types in the respiratory pattern generator, pacemaker cells exhibit the highest sensitivity to channel noise. The model shows that suppressing input from the pons leads to longer inspiratory phases, a reduction in breathing frequency, and larger breath-to-breath variability, whereas enhanced input from the raphe nucleus increases breathing frequency without changing its pattern. A major source of noise in neuronal circuits is the "flickering" of ion currents passing through the neurons' membranes (channel noise), which cannot be suppressed experimentally. Computational simulations are therefore the best way to investigate the effects of this physiological noise by manipulating its level at will. We investigate the role of noise in the respiratory pattern generator and show that endogenous, breath-to-breath variability is tightly linked to the respiratory pattern. Copyright © 2017 the American Physiological Society.

Deep breathing exercises performed 2 months following cardiac surgery: a randomized controlled trial.

PubMed

Westerdahl, Elisabeth; Urell, Charlotte; Jonsson, Marcus; Bryngelsson, Ing-Liss; Hedenström, Hans; Emtner, Margareta

2014-01-01

Postoperative breathing exercises are recommended to cardiac surgery patients. Instructions concerning how long patients should continue exercises after discharge vary, and the significance of treatment needs to be determined. Our aim was to assess the effects of home-based deep breathing exercises performed with a positive expiratory pressure device for 2 months following cardiac surgery. The study design was a prospective, single-blinded, parallel-group, randomized trial. Patients performing breathing exercises 2 months after cardiac surgery (n = 159) were compared with a control group (n = 154) performing no breathing exercises after discharge. The intervention consisted of 30 slow deep breaths performed with a positive expiratory pressure device (10-15 cm H2O), 5 times a day, during the first 2 months after surgery. The outcomes were lung function measurements, oxygen saturation, thoracic excursion mobility, subjective perception of breathing and pain, patient-perceived quality of recovery (40-Item Quality of Recovery score), health-related quality of life (36-Item Short Form Health Survey), and self-reported respiratory tract infection/pneumonia and antibiotic treatment. Two months postoperatively, the patients had significantly reduced lung function, with a mean decrease in forced expiratory volume in 1 second to 93 ± 12% (P< .001) of preoperative values. Oxygenation had returned to preoperative values, and 5 of 8 aspects in the 36-Item Short Form Health Survey were improved compared with preoperative values (P< .01). There were no significant differences between the groups in any of the measured outcomes. No significant differences in lung function, subjective perceptions, or quality of life were found between patients performing home-based deep breathing exercises and control patients 2 months after cardiac surgery.

Chemical sensors for breath gas analysis: the latest developments at the Breath Analysis Summit 2013.

PubMed

Tisch, Ulrike; Haick, Hossam

2014-06-01

Profiling the body chemistry by means of volatile organic compounds (VOCs) in the breath opens exciting new avenues in medical diagnostics. Gas sensors could provide ideal platforms for realizing portable, hand-held breath testing devices in the near future. This review summarizes the latest developments and applications in the field of chemical sensors for diagnostic breath testing that were presented at the Breath Analysis Summit 2013 in Wallerfangen, Germany. Considerable progress has been made towards clinically applicable breath testing devices, especially by utilizing chemo-sensitive nanomaterials. Examples of several specialized breath testing applications are presented that are either based on stand-alone nanomaterial-based sensors being highly sensitive and specific to individual breath compounds over others, or on combinations of several highly specific sensors, or on experimental nanomaterial-based sensors arrays. Other interesting approaches include the adaption of a commercially available MOx-based sensor array to indirect breath testing applications, using a sample pre-concentration method, and the development of compact integrated GC-sensor systems. The recent trend towards device integration has led to the development of fully integrated prototypes of point-of-care devices. We describe and compare the performance of several prototypes that are based on different sensing technologies and evaluate their potential as low-cost and readily available next-generation medical devices.

New breathing functions for the transverse breathing crack of the cracked rotor system: Approach for critical and subcritical harmonic analysis

NASA Astrophysics Data System (ADS)

Al-Shudeifat, Mohammad A.; Butcher, Eric A.

2011-01-01

The actual breathing mechanism of the transverse breathing crack in the cracked rotor system that appears due to the shaft weight is addressed here. As a result, the correct time-varying area moments of inertia for the cracked element cross-section during shaft rotation are also determined. Hence, two new breathing functions are identified to represent the actual breathing effect on the cracked element stiffness matrix. The new breathing functions are used in formulating the time-varying finite element stiffness matrix of the cracked element. The finite element equations of motion are then formulated for the cracked rotor system and solved via harmonic balance method for response, whirl orbits and the shift in the critical and subcritical speeds. The analytical results of this approach are compared with some previously published results obtained using approximate formulas for the breathing mechanism. The comparison shows that the previously used breathing function is a weak model for the breathing mechanism in the cracked rotor even for small crack depths. The new breathing functions give more accurate results for the dynamic behavior of the cracked rotor system for a wide range of the crack depths. The current approach is found to be efficient for crack detection since the critical and subcritical shaft speeds, the unique vibration signature in the neighborhood of the subcritical speeds and the sensitivity to the unbalance force direction all together can be utilized to detect the breathing crack before further damage occurs.

Drinking influences exhaled breath condensate acidity.

PubMed

Kullmann, Tamás; Barta, Imre; Antus, Balázs; Horváth, Ildikó

2008-01-01

Exhaled breath condensate analysis is a developing method for investigating airway pathology. Impact of food and drink on breath condensate composition has not been systematically addressed. The aim of the study was to follow exhaled breath condensate pH after drinking an acidic and a neutral beverage. Breath condensate, capillary blood, and urine of 12 healthy volunteers were collected before and after drinking either 1 l of coke or 1 l of mineral water. The pH of each sample was determined with a blood gas analyzer. The mean difference between the pH of two breath condensate samples collected within 15 min before drinking was 0.13+/-0.03. Condensate pH decreased significantly from 6.29+/-0.02 to 6.24+/-0.02 (p<0.03) after drinking coke and from 6.37+/-0.03 to 6.22+/-0.04 (p<0.003) after drinking water. Drinking coke induced significant changes in blood and urine pH as well. Drinking influences exhaled breath condensate composition and may contribute to the variability of exhaled breath condensate pH.

Dew inspired breathing-based detection of genetic point mutation visualized by naked eye

PubMed Central

Xie, Liping; Wang, Tongzhou; Huang, Tianqi; Hou, Wei; Huang, Guoliang; Du, Yanan

2014-01-01

A novel label-free method based on breathing-induced vapor condensation was developed for detection of genetic point mutation. The dew-inspired detection was realized by integration of target-induced DNA ligation with rolling circle amplification (RCA). The vapor condensation induced by breathing transduced the RCA-amplified variances in DNA contents into visible contrast. The image could be recorded by a cell phone for further or even remote analysis. This green assay offers a naked-eye-reading method potentially applied for point-of-care liver cancer diagnosis in resource-limited regions. PMID:25199907

Dew inspired breathing-based detection of genetic point mutation visualized by naked eye

NASA Astrophysics Data System (ADS)

Xie, Liping; Wang, Tongzhou; Huang, Tianqi; Hou, Wei; Huang, Guoliang; Du, Yanan

2014-09-01

A novel label-free method based on breathing-induced vapor condensation was developed for detection of genetic point mutation. The dew-inspired detection was realized by integration of target-induced DNA ligation with rolling circle amplification (RCA). The vapor condensation induced by breathing transduced the RCA-amplified variances in DNA contents into visible contrast. The image could be recorded by a cell phone for further or even remote analysis. This green assay offers a naked-eye-reading method potentially applied for point-of-care liver cancer diagnosis in resource-limited regions.

Dew inspired breathing-based detection of genetic point mutation visualized by naked eye.

PubMed

Xie, Liping; Wang, Tongzhou; Huang, Tianqi; Hou, Wei; Huang, Guoliang; Du, Yanan

2014-09-09

A novel label-free method based on breathing-induced vapor condensation was developed for detection of genetic point mutation. The dew-inspired detection was realized by integration of target-induced DNA ligation with rolling circle amplification (RCA). The vapor condensation induced by breathing transduced the RCA-amplified variances in DNA contents into visible contrast. The image could be recorded by a cell phone for further or even remote analysis. This green assay offers a naked-eye-reading method potentially applied for point-of-care liver cancer diagnosis in resource-limited regions.

Analytical methodologies for broad metabolite coverage of exhaled breath condensate.

PubMed

Aksenov, Alexander A; Zamuruyev, Konstantin O; Pasamontes, Alberto; Brown, Joshua F; Schivo, Michael; Foutouhi, Soraya; Weimer, Bart C; Kenyon, Nicholas J; Davis, Cristina E

2017-09-01

Breath analysis has been gaining popularity as a non-invasive technique that is amenable to a broad range of medical uses. One of the persistent problems hampering the wide application of the breath analysis method is measurement variability of metabolite abundances stemming from differences in both sampling and analysis methodologies used in various studies. Mass spectrometry has been a method of choice for comprehensive metabolomic analysis. For the first time in the present study, we juxtapose the most commonly employed mass spectrometry-based analysis methodologies and directly compare the resultant coverages of detected compounds in exhaled breath condensate in order to guide methodology choices for exhaled breath condensate analysis studies. Four methods were explored to broaden the range of measured compounds across both the volatile and non-volatile domain. Liquid phase sampling with polyacrylate Solid-Phase MicroExtraction fiber, liquid phase extraction with a polydimethylsiloxane patch, and headspace sampling using Carboxen/Polydimethylsiloxane Solid-Phase MicroExtraction (SPME) followed by gas chromatography mass spectrometry were tested for the analysis of volatile fraction. Hydrophilic interaction liquid chromatography and reversed-phase chromatography high performance liquid chromatography mass spectrometry were used for analysis of non-volatile fraction. We found that liquid phase breath condensate extraction was notably superior compared to headspace extraction and differences in employed sorbents manifested altered metabolite coverages. The most pronounced effect was substantially enhanced metabolite capture for larger, higher-boiling compounds using polyacrylate SPME liquid phase sampling. The analysis of the non-volatile fraction of breath condensate by hydrophilic and reverse phase high performance liquid chromatography mass spectrometry indicated orthogonal metabolite coverage by these chromatography modes. We found that the metabolite coverage could be enhanced significantly with the use of organic solvent as a device rinse after breath sampling to collect the non-aqueous fraction as opposed to neat breath condensate sample. Here, we show the detected ranges of compounds in each case and provide a practical guide for methodology selection for optimal detection of specific compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

MR fingerprinting for rapid quantification of myocardial T1 , T2 , and proton spin density.

PubMed

Hamilton, Jesse I; Jiang, Yun; Chen, Yong; Ma, Dan; Lo, Wei-Ching; Griswold, Mark; Seiberlich, Nicole

2017-04-01

To introduce a two-dimensional MR fingerprinting (MRF) technique for quantification of T 1 , T 2 , and M 0 in myocardium. An electrocardiograph-triggered MRF method is introduced for mapping myocardial T 1 , T 2 , and M 0 during a single breath-hold in as short as four heartbeats. The pulse sequence uses variable flip angles, repetition times, inversion recovery times, and T 2 preparation dephasing times. A dictionary of possible signal evolutions is simulated for each scan that incorporates the subject's unique variations in heart rate. Aspects of the sequence design were explored in simulations, and the accuracy and precision of cardiac MRF were assessed in a phantom study. In vivo imaging was performed at 3 Tesla in 11 volunteers to generate native parametric maps. T 1 and T 2 measurements from the proposed cardiac MRF sequence correlated well with standard spin echo measurements in the phantom study (R 2  > 0.99). A Bland-Altman analysis revealed good agreement for myocardial T 1 measurements between MRF and MOLLI (bias 1 ms, 95% limits of agreement -72 to 72 ms) and T 2 measurements between MRF and T 2 -prepared balanced steady-state free precession (bias, -2.6 ms; 95% limits of agreement, -8.5 to 3.3 ms). MRF can provide quantitative single slice T 1 , T 2 , and M 0 maps in the heart within a single breath-hold. Magn Reson Med 77:1446-1458, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Variability in delivered dose and respirable delivered dose from nebulizers: are current regulatory testing guidelines sufficient to produce meaningful information?

PubMed

Hatley, Ross Hm; Byrne, Sarah M

2017-01-01

To improve convenience to patients, there have been advances in the operation of nebulizers, resulting in fast treatment times and less drug lost to the environment. However, limited attention has been paid to the effects of these developments on the delivered dose (DD) and respirable delivered dose (RDD). Published pharmacopoeia and ISO testing guidelines for adult-use testing utilize a single breathing pattern, which may not be sufficient to enable effective comparisons between the devices. The DD of 5 mg of salbutamol sulfate into adult breathing patterns with inhalation:exhalation (I:E) ratios between 1:1 and 1:4 was determined. Droplet size was determined by laser diffraction and RDD calculated. Nine different nebulizer brands with different modes of operation (conventional, venturi, breath-enhanced, mesh, and breath-activated) were tested. Between the non-breath-activated nebulizers, a 2.5-fold difference in DD (~750-1,900 µg salbutamol) was found; with RDD, there was a more than fourfold difference (~210-980 µg). With increasing time spent on exhalation, there were progressive reductions in DD and RDD, with the RDD at an I:E ratio of 1:4 being as little as 40% of the dose with the 1:1 I:E ratio. The DD and RDD from the breath-activated mesh nebulizer were independent of the I:E ratio, and for the breath-activated jet nebulizer, there was less than 20% change in RDD between the I:E ratios of 1:1 and 1:4. Comparing nebulizers using the I:E ratio recommended in the guidelines does not predict relative performance between the devices at other ratios. There was significant variance in DD or RDD between different brands of non-breath-activated nebulizer. In future, consideration should be given to revision of the test protocols included in the guidelines, to reflect more accurately the potential therapeutic dose that is delivered to a realistic spectrum of breathing patterns.

Reproducibility of CT Perfusion Parameters in Liver Tumors and Normal Liver

PubMed Central

Ng, Chaan S.; Chandler, Adam G.; Wei, Wei; Herron, Delise H.; Anderson, Ella F.; Kurzrock, Razelle; Charnsangavej, Chusilp

2011-01-01

Purpose: To assess the reproducibility of computed tomographic (CT) perfusion measurements in liver tumors and normal liver and effects of motion and data acquisition time on parameters. Materials and Methods: Institutional review board approval and written informed consent were obtained for this prospective study. The study complied with HIPAA regulations. Two CT perfusion scans were obtained 2–7 days apart in seven patients with liver tumors with two scanning phases (phase 1: 30-second breath-hold cine; phase 2: six intermittent free-breathing cines) spanning 135 seconds. Blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability–surface area product (PS) for tumors and normal liver were calculated from phase 1 with and without rigid registration and, for combined phases 1 and 2, with manually and rigid-registered phase 2 images, by using deconvolution modeling. Variability was assessed with within-patient coefficients of variation (CVs) and Bland-Altman analyses. Results: For tumors, BF, BV, MTT, and PS values and reproducibility varied by analytical method, the former by up to 11%, 23%, 21%, and 138%, respectively. Median PS values doubled with the addition of phase 2 data to phase 1 data. The best overall reproducibility was obtained with rigidly registered phase 1 and phase 2 images, with within-patient CVs for BF, BV, MTT, and PS of 11.2%, 14.4%, 5.5% and 12.1%, respectively. Normal liver evaluations were similar, except with marginally lower variability. Conclusion: Absolute values and reproducibility of CT perfusion parameters were markedly influenced by motion and data acquisition time. PS, in particular, probably requires data acquisition beyond a single breath hold, for which motion-correction techniques are likely necessary. © RSNA, 2011 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11110331/-/DC1 PMID:21788525

Motion induced interplay effects for VMAT radiotherapy.

PubMed

Edvardsson, Anneli; Nordström, Fredrik; Ceberg, Crister; Ceberg, Sofie

2018-04-19

The purpose of this study was to develop a method to simulate breathing motion induced interplay effects for volumetric modulated arc therapy (VMAT), to verify the proposed method with measurements, and to use the method to investigate how interplay effects vary with different patient- and machine specific parameters. VMAT treatment plans were created on a virtual phantom in a treatment planning system (TPS). Interplay effects were simulated by dividing each plan into smaller sub-arcs using an in-house developed software and shifting the isocenter for each sub-arc to simulate a sin 6 breathing motion in the superior-inferior direction. The simulations were performed for both flattening-filter (FF) and flattening-filter free (FFF) plans and for different breathing amplitudes, period times, initial breathing phases, dose levels, plan complexities, CTV sizes, and collimator angles. The resulting sub-arcs were calculated in the TPS, generating a dose distribution including the effects of motion. The interplay effects were separated from dose blurring and the relative dose differences to 2% and 98% of the CTV volume (ΔD 98% and ΔD 2% ) were calculated. To verify the simulation method, measurements were carried out, both static and during motion, using a quasi-3D phantom and a motion platform. The results of the verification measurements during motion were comparable to the results of the static measurements. Considerable interplay effects were observed for individual fractions, with the minimum ΔD 98% and maximum ΔD 2% being  -16.7% and 16.2%, respectively. The extent of interplay effects was larger for FFF compared to FF and generally increased for higher breathing amplitudes, larger period times, lower dose levels, and more complex treatment plans. Also, the interplay effects varied considerably with the initial breathing phase, and larger variations were observed for smaller CTV sizes. In conclusion, a method to simulate motion induced interplay effects was developed and verified with measurements, which allowed for a large number of treatment scenarios to be investigated. The simulations showed large interplay effects for individual fractions and that the extent of interplay effects varied with the breathing pattern, FFF/FF, dose level, CTV size, collimator angle, and the complexity of the treatment plan.

Motion induced interplay effects for VMAT radiotherapy

NASA Astrophysics Data System (ADS)

Edvardsson, Anneli; Nordström, Fredrik; Ceberg, Crister; Ceberg, Sofie

2018-04-01

The purpose of this study was to develop a method to simulate breathing motion induced interplay effects for volumetric modulated arc therapy (VMAT), to verify the proposed method with measurements, and to use the method to investigate how interplay effects vary with different patient- and machine specific parameters. VMAT treatment plans were created on a virtual phantom in a treatment planning system (TPS). Interplay effects were simulated by dividing each plan into smaller sub-arcs using an in-house developed software and shifting the isocenter for each sub-arc to simulate a sin6 breathing motion in the superior–inferior direction. The simulations were performed for both flattening-filter (FF) and flattening-filter free (FFF) plans and for different breathing amplitudes, period times, initial breathing phases, dose levels, plan complexities, CTV sizes, and collimator angles. The resulting sub-arcs were calculated in the TPS, generating a dose distribution including the effects of motion. The interplay effects were separated from dose blurring and the relative dose differences to 2% and 98% of the CTV volume (ΔD98% and ΔD2%) were calculated. To verify the simulation method, measurements were carried out, both static and during motion, using a quasi-3D phantom and a motion platform. The results of the verification measurements during motion were comparable to the results of the static measurements. Considerable interplay effects were observed for individual fractions, with the minimum ΔD98% and maximum ΔD2% being  ‑16.7% and 16.2%, respectively. The extent of interplay effects was larger for FFF compared to FF and generally increased for higher breathing amplitudes, larger period times, lower dose levels, and more complex treatment plans. Also, the interplay effects varied considerably with the initial breathing phase, and larger variations were observed for smaller CTV sizes. In conclusion, a method to simulate motion induced interplay effects was developed and verified with measurements, which allowed for a large number of treatment scenarios to be investigated. The simulations showed large interplay effects for individual fractions and that the extent of interplay effects varied with the breathing pattern, FFF/FF, dose level, CTV size, collimator angle, and the complexity of the treatment plan.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, D; Kang, S; Kim, T

Purpose: Patient breathing-related sorting method of projections in 4D digital tomosythesis (DTS) can be suffered from severe artifacts due to non-uniform angle distribution of projections and noncoplanar reconstructed images for each phase. In this study, we propose a method for optimally acquiring projection images in 4D DTS. Methods: In this method every pair of projections at x-ray tube’s gantry angles symmetrical with respect to the center of the range of gantry rotation is obtained at the same respiration amplitude. This process is challenging but becomes feasible with visual-biofeedback using a patient specific respiration guide wave which is in sinusoidal shapemore » (i.e., smooth and symmetrical enough). Depending on scan parameters such as the number of acquisition points per cycle, total scan angle and projections per acquisition amplitude, acquisition sequence is pre-determined. A simulation study for feasibility test was performed. To mimic actual situation closely, a group of volunteers were recruited and breathing data were acquired both with/without biofeedback. Then, x-ray projections for a humanoid phantom were virtually performed following (1) the breathing data from volunteers without guide, (2) the breathing data with guide and (3) the planned breathing data (i.e., ideal situation). Images from all of 3 scenarios were compared. Results: Scenario #2 showed significant artifact reduction compared to #1 while did minimal increase from the ideal situation (i.e., scenario #3). We verified the performance of the method with regard to the degree of inaccuracy during respiratory guiding. Also, the scan angle dependence-related differences in the DTS images could reduce between using the proposed method and the established patient breathing-related sorting method. Conclusion: Through the proposed 4D DTS method, it is possible to improve the accuracy of image guidance between intra/inter fractions with relatively low imaging dose. This research was supported by the Mid-career Researcher Program through NRF funded by the Ministry of Science, ICT & Future Planning of Korea (NRF-2014R1A2A1A10050270) and by the Radiation Technology R&D program through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning (No. 2013M2A2A7038291)« less

A Non-Invasive Method for Estimating Cardiopulmonary Variables Using Breath-by-Breath Injection of Two Tracer Gases.

PubMed

Clifton, Lei; Clifton, David A; Hahn, Clive E W; Farmeryy, Andrew D

2013-01-01

Conventional methods for estimating cardiopulmonary variables usually require complex gas analyzers and the active co-operation of the patient. Therefore, they are not compatible with the crowded environment of the intensive care unit (ICU) or operating theatre, where patient co-operation is typically impossible. However, it is these patients that would benefit the most from accurate estimation of cardiopulmonary variables, because of their critical condition. This paper describes the results of a collaborative development between an anesthesiologists and biomedical engineers to create a compact and non-invasive system for the measurement of cardiopulmonary variables such as lung volume, airway dead space volume, and pulmonary blood flow. In contrast with conventional methods, the compact apparatus and non-invasive nature of the proposed method allow it to be used in the ICU, as well as in general clinical settings. We propose the use of a non-invasive method, in which tracer gases are injected into the patient's inspired breath, and the concentration of the tracer gases is subsequently measured. A novel breath-by-breath tidal ventilation model is then used to estimate the value of a patient's cardiopulmonary variables. Experimental results from an artificial lung demonstrate minimal error in the estimation of known parameters using the proposed method. Results from analysis of a cohort of 20 healthy volunteers (within the Oxford University Hospitals NHS Trust) show that the values of estimated cardiopulmonary variables from these subjects lies within the expected ranges. Advantages of this method are that it is non-invasive, compact, portable, and can perform analysis in real time with less than 1 min of acquired respiratory data.

CO[subscript 2] Rebreathing: An Undergraduate Laboratory to Study the Chemical Control of Breathing

ERIC Educational Resources Information Center

Domnik, N. J.; Turcotte, S. E.; Yuen, N. Y.; Iscoe, S.; Fisher, J. T.

2013-01-01

The Read CO[subscript]2 rebreathing method (Read DJ. "A clinical method for assessing the ventilatory response to carbon dioxide." "Australas Ann Med" 16: 20-32, 1967) provides a simple and reproducible approach for studying the chemical control of breathing. It has been widely used since the modifications made by Duffin and…

Detection of creatinine in exhaled breath of humans with chronic kidney disease by extractive electrospray ionization mass spectrometry.

PubMed

Zeng, Qian; Li, Penghui; Cai, Yunfeng; Zhou, Wei; Wang, Haidong; Luo, Jiao; Ding, Jianhua; Chen, Huanwen

2016-02-09

Exhaled breath contains chemicals that have a diagnostic value in human pathologies. Here in vivo breath analysis of creatinine has been demonstrated by constructing a novel platform based on extractive electrospray ionization mass spectrometry (EESI-MS) without sample pretreatment. Under optimized experimental conditions, the limit of creatinine detection in breath was 30.57 ng L(-1), and the linear range of detection was from 0.3 μg L(-1) to 100 μg L(-1). The concentration range of creatinine in the exhaled breath of 50 volunteers with chronic kidney disease was from 42 pptv to 924 pptv, and the range of the relative standard deviations was from 9.3% to 19.2%. The method provides high sensitivity, high specificity and high speed for semi-quantitative analysis of creatinine in exhaled human breath.

Effects of deep breathing on internal oblique and multifidus muscle activity in three sitting postures

PubMed Central

Ko, Min-Joo; Jung, Eun-Joo; Kim, Moon-Hwan; Oh, Jae-Seop

2018-01-01

[Purpose] This study was to investigate differences in the level of activity of the external oblique (EO), internal oblique (IO), and multifidus (MF) muscles with deep breathing in three sitting postures. [Subjects and Methods] Sixteen healthy women were recruited. The muscle activity (EO, IO, MF) of all subjects was measured in three sitting postures (slumped, thoracic upright, and lumbo-pelvic upright sitting postures) using surface electromyography. The activity of the same muscles was then remeasured in the three sitting postures during deep breathing. [Results] Deep breathing significantly increased activity in the EO, IO, and MF compared with normal breathing. Comparing postures, the activity of the MF and IO muscles was highest in the lumbo-pelvic upright sitting posture. [Conclusion] An lumbo-pelvic upright sitting posture with deep breathing could increase IO and MF muscle activity, thus improving lumbo-pelvic region stability. PMID:29706695

Applications of principal component analysis to breath air absorption spectra profiles classification

NASA Astrophysics Data System (ADS)

Kistenev, Yu. V.; Shapovalov, A. V.; Borisov, A. V.; Vrazhnov, D. A.; Nikolaev, V. V.; Nikiforova, O. Y.

2015-12-01

The results of numerical simulation of application principal component analysis to absorption spectra of breath air of patients with pulmonary diseases are presented. Various methods of experimental data preprocessing are analyzed.

Tests for H. pylori

MedlinePlus

Peptic ulcer disease - H. pylori ; PUD - H. pylori ... There are several methods to test for H. pylori infection. Breath Test (Carbon Isotope-urea Breath Test, or UBT) Up to 2 weeks before the test, you need to stop taking ...

Automated measurement of respiratory gas exchange by an inert gas dilution technique

NASA Technical Reports Server (NTRS)

Sawin, C. F.; Rummel, J. A.; Michel, E. L.

1974-01-01

A respiratory gas analyzer (RGA) has been developed wherein a mass spectrometer is the sole transducer required for measurement of respiratory gas exchange. The mass spectrometer maintains all signals in absolute phase relationships, precluding the need to synchronize flow and gas composition as required in other systems. The RGA system was evaluated by comparison with the Douglas bag technique. The RGA system established the feasibility of the inert gas dilution method for measuring breath-by-breath respiratory gas exchange. This breath-by-breath analytical capability permits detailed study of transient respiratory responses to exercise.

Residential Air Pollution and Associations with Wheeze and Shortness of Breath in Adults: A Combined Analysis of Cross-Sectional Data from Two Large European Cohorts

PubMed Central

de Hoogh, Kees; Probst-Hensch, Nicole; Mbatchou, Stéphane; Eeftens, Marloes; Cai, Yutong; Schindler, Christian; Fortier, Isabel; Hodgson, Susan; Gaye, Amadou; Stolk, Ronald; Hansell, Anna

2017-01-01

Background: Research examining associations between air pollution exposure and respiratory symptoms in adults has generally been inconclusive. This may be related in part to sample size issues, which also preclude analysis in potentially vulnerable subgroups. Objectives: We estimated associations between air pollution exposures and the prevalence of wheeze and shortness of breath using harmonized baseline data from two very large European cohorts, Lifelines (2006–2013) and UK Biobank (2006–2010). Our aim was also to determine whether the relationship between air pollution and respiratory symptom prevalence differed between individuals with different characteristics. Methods: Cross-sectional analyses explored associations between prevalence of self-reported wheeze and shortness of breath and annual mean particulate matter with aerodynamic diameter <2.5μm, 2.5–10μm, and <10μm (PM2.5, PMcoarse, and PM10, respectively) and nitrogen dioxide (NO2) concentrations at place of residence using logistic regression. Subgroup analyses and tests for interaction were performed for age, sex, smoking status, household income, obesity status, and asthma status. Results: All PM exposures were associated with respiratory symptoms based on single-pollutant models, with the largest associations seen for PM2.5 with prevalence of wheezing {odds ratio (OR)=1.16 per 5μg/m³ [95% confidence interval (CI): 1.11, 1.21]} and shortness of breath [OR=1.61 per 5μg/m³ (95% CI: 1.45, 1.78)]. The association between shortness of breath and a 5-μg/m³ increment in PM2.5 was significantly higher for individuals from lower-[OR=1.73 (95% CI: 1.52, 1.97)] versus higher-income households [OR=1.31 (95% CI: 1.11, 1.55); p-interaction=0.005), whereas the association between PM2.5 and wheeze was limited to lower-income participants [OR=1.30 (95% CI: 1.22, 1.38) vs. OR=1.02; (95% CI: 0.96, 1.08); p-interaction<0.001]. Exposure to NO2 also showed positive associations with wheeze and shortness of breath. Conclusion: Exposure to PM and NO2 air pollution was associated with the prevalence of wheeze and shortness of breath in this large study, with stronger associations between PM2.5 and both outcomes among lower- versus higher-income participants. https://doi.org/10.1289/EHP1353 PMID:28963089

DEVELOPMENT OF A SCREENING PROTOCOL TO IDENTIFY INDIVIDUALS WITH DYSFUNCTIONAL BREATHING

PubMed Central

Kiesel, Kyle; Rhodes, Tonya; Mueller, Jacob; Waninger, Alyssa; Butler, Robert

2017-01-01

Introduction Dysfunctional breathing (DB) has been linked to health conditions including low back pain and neck pain and adversely effects the musculoskeletal system. Individuals with DB often have decreased pain thresholds and impaired motor control, balance, and movement. No single test or screen identifies DB, which is multi-dimensional, and includes biochemical, biomechanical, and psychophysiological components. Several tools assess and test for DB, but no screen exists to determine whether additional testing and assessment are indicated. Purpose/Background The purpose of this study was to develop a breathing screening procedure that could be utilized by fitness and healthcare providers to screen for the presence of disordered breathing. A diagnostic test study approach was utilized to establish the diagnostic accuracy of the newly developed screen for DB. Methods A convenience sample of 51 subjects (27 females, 27.0 years, BMI 23.3) were included. To test for DB related to the biochemical dimension, end-tidal CO2 (ETCO2) was measured with a capnography unit. To test for DB related to biomechanical dimension, the Hi-Lo test was utilized. To test for DB related to the psychophysiological dimension, the Self Evaluation of Breathing Symptoms Questionnaire (SEBQ) and Nijmegen questionnaires were utilized. Potential screening items that have been shown to be related to DB in previous research and that could be performed by non-health care personnel were utilized to create the index test including activity level, breath hold time (BHT), respiration rate, and the Functional Movement Screen (FMS™). Results There were no strong correlations between the three measures of DB. Five subjects had normal breathing, 14 failed at least one measure, 20 failed at least two, and 12 failed all three. To develop screening items for each dimension, data were examined for association with failure. BHT and a four-item mini-questionnaire were identified as the most closely associated variables with failure of all three dimensions. A BHT of < 25 seconds and four questions were combined and yielded a sensitivity of 0.89 (0.85-0.93) and a specificity of 0.60 (0.18-0.92) for clinical identification of DB. Conclusion Easily obtained clinical measures of BHT and four questions can be utilized to screen for the presence of DB. If the screen is passed, there is an 89% chance that DB is not present. If the screen is failed, further assessment is recommended. Level of Evidence 2b PMID:29181255

Evaluation of breathing patterns for respiratory-gated radiation therapy using the respiration regularity index

NASA Astrophysics Data System (ADS)

Cheong, Kwang-Ho; Lee, MeYeon; Kang, Sei-Kwon; Yoon, Jai-Woong; Park, SoAh; Hwang, Taejin; Kim, Haeyoung; Kim, KyoungJu; Han, Tae Jin; Bae, Hoonsik

2015-01-01

Despite the considerable importance of accurately estimating the respiration regularity of a patient in motion compensation treatment, not to mention the necessity of maintaining that regularity through the following sessions, an effective and simply applicable method by which those goals can be accomplished has rarely been reported. The authors herein propose a simple respiration regularity index based on parameters derived from a correspondingly simplified respiration model. In order to simplify a patient's breathing pattern while preserving the data's intrinsic properties, we defined a respiration model as a cos4( ω( t) · t) wave form with a baseline drift. According to this respiration formula, breathing-pattern fluctuation could be explained using four factors: the sample standard deviation of respiration period ( s f ), the sample standard deviation of amplitude ( s a ) and the results of a simple regression of the baseline drift (slope as β, and standard deviation of residuals as σ r ) of a respiration signal. The overall irregularity ( δ) was defined as , where is a variable newly-derived by using principal component analysis (PCA) for the four fluctuation parameters and has two principal components ( ω 1, ω 2). The proposed respiration regularity index was defined as ρ = ln(1 + (1/ δ))/2, a higher ρ indicating a more regular breathing pattern. We investigated its clinical relevance by comparing it with other known parameters. Subsequently, we applied it to 110 respiration signals acquired from five liver and five lung cancer patients by using real-time position management (RPM; Varian Medical Systems, Palo Alto, CA). Correlations between the regularity of the first session and the remaining fractions were investigated using Pearson's correlation coefficient. Additionally, the respiration regularity was compared between the liver and lung cancer patient groups. The respiration regularity was determined based on ρ; patients with ρ < 0.3 showed worse regularity than the others whereas ρ > 0.7 was suitable for respiratory-gated radiation therapy (RGRT). Fluctuations in the breathing cycle and the amplitude were especially determinative of ρ. If the respiration regularity of a patient's first session was known, it could be estimated through subsequent sessions. Notably, the breathing patterns of the lung cancer patients were more irregular than those of the liver cancer patients. Respiration regularity could be objectively determined by using a composite index, ρ. Such a single-index testing of respiration regularity can facilitate determination of RGRT availability in clinical settings, especially for free-breathing cases.

Breath acidification in adolescent runners exposed to atmospheric pollution: A prospective, repeated measures observational study

PubMed Central

Ferdinands, Jill M; Crawford, Carol A Gotway; Greenwald, Roby; Van Sickle, David; Hunter, Eric; Teague, W Gerald

2008-01-01

Background Vigorous outdoors exercise during an episode of air pollution might cause airway inflammation. The purpose of this study was to examine the effects of vigorous outdoor exercise during peak smog season on breath pH, a biomarker of airway inflammation, in adolescent athletes. Methods We measured breath pH both pre- and post-exercise on ten days during peak smog season in 16 high school athletes engaged in daily long-distance running in a downwind suburb of Atlanta. The association of post-exercise breath pH with ambient ozone and particulate matter concentrations was tested with linear regression. Results We collected 144 pre-exercise and 146 post-exercise breath samples from 16 runners (mean age 14.9 years, 56% male). Median pre-exercise breath pH was 7.58 (interquartile range: 6.90 to 7.86) and did not change significantly after exercise. We observed no significant association between ambient ozone or particulate matter and post-exercise breath pH. However both pre- and post-exercise breath pH were strikingly low in these athletes when compared to a control sample of 14 relatively sedentary healthy adults and to published values of breath pH in healthy subjects. Conclusion Although we did not observe an acute effect of air pollution exposure during exercise on breath pH, breath pH was surprisingly low in this sample of otherwise healthy long-distance runners. We speculate that repetitive vigorous exercise may induce airway acidification. PMID:18328105

Marital status and sleep-disordered breathing in a sample of middle-aged French men.

PubMed

Teculescu, D; Hannhart, B; Virion, J M; Montaut-Verient, B; Michaely, J P

2004-01-01

The aim of the present study was to test the hypothesis that unmarried (single) men have more sleep-disordered breathing symptoms due to a higher prevalence of obesity and a less healthy lifestyle than men living with a partner. Men (499) aged 23-66 years completed a structured questionnaire, had standard anthropometric measurements and a simple, noninvasive nose-throat examination. Of the 499,496 subjects answered the question concerning their marital status; 86% of them were married or lived with a partner (reference group) and the other 14% had never been married, divorced, or widowed ("single" group, considered at risk). Single subjects were younger, included slightly more smokers (30 vs. 23%) and more subjects with a history of chronic bronchitis, and less frequently had a large soft palate. The prevalence of sleep-disordered symptoms was not significantly different between the two groups. However, a study involving a larger number of subjects with information regarding alcoholic consumption may be needed to further evaluate this question.

Design of a breath analysis system for diabetes screening and blood glucose level prediction.

PubMed

Yan, Ke; Zhang, David; Wu, Darong; Wei, Hua; Lu, Guangming

2014-11-01

It has been reported that concentrations of several biomarkers in diabetics' breath show significant difference from those in healthy people's breath. Concentrations of some biomarkers are also correlated with the blood glucose levels (BGLs) of diabetics. Therefore, it is possible to screen for diabetes and predict BGLs by analyzing one's breath. In this paper, we describe the design of a novel breath analysis system for this purpose. The system uses carefully selected chemical sensors to detect biomarkers in breath. Common interferential factors, including humidity and the ratio of alveolar air in breath, are compensated or handled in the algorithm. Considering the intersubject variance of the components in breath, we build subject-specific prediction models to improve the accuracy of BGL prediction. A total of 295 breath samples from healthy subjects and 279 samples from diabetic subjects were collected to evaluate the performance of the system. The sensitivity and specificity of diabetes screening are 91.51% and 90.77%, respectively. The mean relative absolute error for BGL prediction is 21.7%. Experiments show that the system is effective and that the strategies adopted in the system can improve its accuracy. The system potentially provides a noninvasive and convenient method for diabetes screening and BGL monitoring as an adjunct to the standard criteria.

Breath Group Analysis for Reading and Spontaneous Speech in Healthy Adults

PubMed Central

Wang, Yu-Tsai; Green, Jordan R.; Nip, Ignatius S.B.; Kent, Ray D.; Kent, Jane Finley

2010-01-01

Aims The breath group can serve as a functional unit to define temporal and fundamental frequency (f0) features in continuous speech. These features of the breath group are determined by the physiologic, linguistic, and cognitive demands of communication. Reading and spontaneous speech are two speaking tasks that vary in these demands and are commonly used to evaluate speech performance for research and clinical applications. The purpose of this study is to examine differences between reading and spontaneous speech in the temporal and f0 aspects of their breath groups. Methods Sixteen participants read two passages and answered six questions while wearing a circumferentially vented mask connected to a pneumotach. The aerodynamic signal was used to identify inspiratory locations. The audio signal was used to analyze task differences in breath group structure, including temporal and f0 components. Results The main findings were that spontaneous speech task exhibited significantly more grammatically inappropriate breath group locations and longer breath group duration than did the passage reading task. Conclusion The task differences in the percentage of grammatically inadequate breath group locations and in breath group duration for healthy adult speakers partly explain the differences in cognitive-linguistic load between the passage reading and spontaneous speech. PMID:20588052

Measurement and prediction of indoor air quality using a breathing thermal manikin.

PubMed

Melikov, A; Kaczmarczyk, J

2007-02-01

The analyses performed in this paper reveal that a breathing thermal manikin with realistic simulation of respiration including breathing cycle, pulmonary ventilation rate, frequency and breathing mode, gas concentration, humidity and temperature of exhaled air and human body shape and surface temperature is sensitive enough to perform reliable measurement of characteristics of air as inhaled by occupants. The temperature, humidity, and pollution concentration in the inhaled air can be measured accurately with a thermal manikin without breathing simulation if they are measured at the upper lip at a distance of <0.01 m from the face. Body surface temperature, shape and posture as well as clothing insulation have impact on the measured inhaled air parameters. Proper simulation of breathing, especially of exhalation, is needed for studying the transport of exhaled air between occupants. A method for predicting air acceptability based on inhaled air parameters and known exposure-response relationships established in experiments with human subjects is suggested. Recommendations for optimal simulation of human breathing by means of a breathing thermal manikin when studying pollution concentration, temperature and humidity of the inhaled air as well as the transport of exhaled air (which may carry infectious agents) between occupants are outlined. In order to compare results obtained with breathing thermal manikins, their nose and mouth geometry should be standardized.

Measurement of hepatic functional mass by means of 13C-methacetin and 13C-phenylalanine breath tests in chronic liver disease: Comparison with Child-Pugh score and serum bile acid levels

PubMed Central

Festi, D.; Capodicasa, S.; Sandri, L.; Colaiocco-Ferrante, L.; Staniscia, T.; Vitacolonna, E.; Vestito, A.; Simoni, P.; Mazzella, G.; Portincasa, P.; Roda, E.; Colecchia, A.

2005-01-01

AIM: To evaluate and compare the clinical usefulness of 13C-phenylalanine and 13C-methacetin breath tests in quantitating functional hepatic mass in patients with chronic liver disease and to further compare these results with those of conventional tests, Child-Pugh score and serum bile acid levels. METHODS: One hundred and forty patients (50 HCV- related chronic hepatitis, 90 liver cirrhosis patients) and 40 matched healthy controls were studied. Both breath test and routine liver test, serum levels of cholic and chenodeoxycholic acid conjugates were evaluated. RESULTS: Methacetin breath test, expressed as 60 min cumulative percent of oxidation, discriminated the hepatic functional capacity not only between controls and liver disease patients, but also between different categories of chronic liver disease patients. Methacetin breath test was correlated with liver function tests and serum bile acids. Furthermore, methacetin breath test, as well as serum bile acids, were highly predictive of Child-Pugh scores. The diagnostic power of phenylalanine breath test was always less than that of methacetin breath test. CONCLUSION: Methacetin breath test represents a safe and accurate diagnostic tool in the evaluation of hepatic functional mass in chronic liver disease patients. PMID:15609414

The QED engine spectrum - Fusion-electric propulsion for air-breathing to interstellar flight

NASA Technical Reports Server (NTRS)

Bussard, Robert W.; Jameson, Lorin W.

1993-01-01

A new inertial-electrostatic-fusion direct electric power source can be used to drive a relativistic e-beam to heat propellant. The resulting system is shown to yield specific impulse and thrust/mass ratio 2-3 orders of magnitude larger than from other advanced propulsion concepts. This QED system can be applied to aerospace vehicles from air-breathing to near-interstellar flight. Examples are given for Earth/Mars flight missions, that show transit times of 40 d with 20 percent payload in single-stage vehicles.

Low-power system for the acquisition of the respiratory signal of neonates using diaphragmatic electromyography

PubMed Central

Torres, Róbinson; López-Isaza, Sergio; Mejía-Mejía, Elisa; Paniagua, Viviana; González, Víctor

2017-01-01

Introduction An apnea episode is defined as the cessation of breathing for ≥15 seconds or as any suspension of breathing accompanied by hypoxia and bradycardia. Obtaining information about the respiratory system in a neonate can be accomplished using electromyography signals from the diaphragm muscle. Objective The purpose of this paper is to illustrate a method by which the respiratory and electrocardiographic signals from neonates can be obtained using diaphragmatic electromyography. Materials and methods The system was developed using single-supply, micropower components, which deliver a low-power consumption system appropriate for the development of portable devices. The stages of the system were tested in both adult and neonate patients. Results The system delivers signals as those expected in both patients and allows the acquisition of respiratory signals directly from the diaphragmatic electromyography. Conclusion This low-power system may present a good alternative for monitoring the cardiac and respiratory activity in newborn babies, both in the hospital and at home. Significance The system delivers good signals but needs to be validated for its use in neonates. It is being used in the Neonatal Intensive Care Unit of the Hospital General de Medellín Luz Castro de Gutiérrez. PMID:28260954

Pure-rotational spectrometry: a vintage analytical method applied to modern breath analysis.

PubMed

Hrubesh, Lawrence W; Droege, Michael W

2013-09-01

Pure-rotational spectrometry (PRS) is an established method, typically used to study structures and properties of polar gas-phase molecules, including isotopic and isomeric varieties. PRS has also been used as an analytical tool where it is particularly well suited for detecting or monitoring low-molecular-weight species that are found in exhaled breath. PRS is principally notable for its ultra-high spectral resolution which leads to exceptional specificity to identify molecular compounds in complex mixtures. Recent developments using carbon aerogel for pre-concentrating polar molecules from air samples have extended the sensitivity of PRS into the part-per-billion range. In this paper we describe the principles of PRS and show how it may be configured in several different modes for breath analysis. We discuss the pre-concentration concept and demonstrate its use with the PRS analyzer for alcohols and ammonia sampled directly from the breath.

Planning 4D intensity-modulated arc therapy for tumor tracking with a multileaf collimator

NASA Astrophysics Data System (ADS)

Niu, Ying; Betzel, Gregory T.; Yang, Xiaocheng; Gui, Minzhi; Parke, William C.; Yi, Byongyong; Yu, Cedric X.

2017-02-01

This study introduces a practical four-dimensional (4D) planning scheme of IMAT using 4D computed tomography (4D CT) for planning tumor tracking with dynamic multileaf beam collimation. We assume that patients can breathe regularly, i.e. the same way as during 4D CT with an unchanged period and amplitude, and that the start of 4D-IMAT delivery can be synchronized with a designated respiratory phase. Each control point of the IMAT-delivery process can be associated with an image set of 4D CT at a specified respiratory phase. Target is contoured at each respiratory phase without a motion-induced margin. A 3D-IMAT plan is first optimized on a reference-phase image set of 4D CT. Then, based on the projections of the planning target volume in the beam’s eye view at different respiratory phases, a 4D-IMAT plan is generated by transforming the segments of the optimized 3D plan by using a direct aperture deformation method. Compensation for both translational and deformable tumor motion is accomplished, and the smooth delivery of the transformed plan is ensured by forcing connectivity between adjacent angles (control points). It is envisioned that the resultant plans can be delivered accurately using the dose rate regulated tracking method which handles breathing irregularities (Yi et al 2008 Med. Phys. 35 3955-62).This planning process is straightforward and only adds a small step to current clinical 3D planning practice. Our 4D planning scheme was tested on three cases to evaluate dosimetric benefits. The created 4D-IMAT plans showed similar dose distributions as compared with the 3D-IMAT plans on a single static phase, indicating that our method is capable of eliminating the dosimetric effects of breathing induced target motion. Compared to the 3D-IMAT plans with large treatment margins encompassing respiratory motion, our 4D-IMAT plans reduced radiation doses to surrounding normal organs and tissues.

Breath biomarkers in toxicology.

PubMed

Pleil, Joachim D

2016-11-01

Exhaled breath has joined blood and urine as a valuable resource for sampling and analyzing biomarkers in human media for assessing exposure, uptake metabolism, and elimination of toxic chemicals. This article focuses current use of exhaled gas, aerosols, and vapor in human breath, the methods for collection, and ultimately the use of the resulting data. Some advantages of breath are the noninvasive and self-administered nature of collection, the essentially inexhaustible supply, and that breath sampling does not produce potentially infectious waste such as needles, wipes, bandages, and glassware. In contrast to blood and urine, breath samples can be collected on demand in rapid succession and so allow toxicokinetic observations of uptake and elimination in any time frame. Furthermore, new technologies now allow capturing condensed breath vapor directly, or just the aerosol fraction alone, to gain access to inorganic species, lung pH, proteins and protein fragments, cellular DNA, and whole microorganisms from the pulmonary microbiome. Future applications are discussed, especially the use of isotopically labeled probes, non-targeted (discovery) analysis, cellular level toxicity testing, and ultimately assessing "crowd breath" of groups of people and the relation to dose of airborne and other environmental chemicals at the population level.

Association between the rapid shallow breathing index and extubation success in patients with traumatic brain injury

PubMed Central

dos Reis, Helena França Correia; Almeida, Mônica Lajana Oliveira; da Silva, Mário Ferreira; Moreira, Julião Oliveira; Rocha, Mário de Seixas

2013-01-01

Objective To investigate the association between the rapid shallow breathing index and successful extubation in patients with traumatic brain injury. Methods This study was a prospective study conducted in patients with traumatic brain injury of both genders who underwent mechanical ventilation for at least two days and who passed a spontaneous breathing trial. The minute volume and respiratory rate were measured using a ventilometer, and the data were used to calculate the rapid shallow breathing index (respiratory rate/tidal volume). The dependent variable was the extubation outcome: reintubation after up to 48 hours (extubation failure) or not (extubation success). The independent variable was the rapid shallow breathing index measured after a successful spontaneous breathing trial. Results The sample comprised 119 individuals, including 111 (93.3%) males. The average age of the sample was 35.0±12.9 years old. The average duration of mechanical ventilation was 8.1±3.6 days. A total of 104 (87.4%) participants achieved successful extubation. No association was found between the rapid shallow breathing index and extubation success. Conclusion The rapid shallow breathing index was not associated with successful extubation in patients with traumatic brain injury. PMID:24213084

Noninvasive determination of respiratory ozone absorption: development of a fast-responding ozone analyzer.

PubMed

Ultman, J S; Ben-Jebria, A

1991-03-01

We developed a chemiluminescent ozone analyzer and constructed an ozone bolus generator with the eventual goal of using a bolus-response method to measure noninvasively the longitudinal distribution of ozone absorption in human lungs. Because the analyzer will be used to sample gases within a single breath, it must have a sufficiently rapid response to monitor changes in ozone concentration during a four-second breathing period, yet its sampling flow must be small enough that it does not interfere with quiet respiratory flows of 300 mL/sec. Our analyzer, which is based on the chemiluminescent reaction between 2-methyl-2-butene and ozone, has favorable performance characteristics: a 90 percent step-response time of 110 msec; a linear calibration from 0.03 to 10 parts per million (ppm)2 with a sensitivity of 2.3 nA/ppm; a signal-to-noise ratio of 30 evaluated at 0.5 ppm; and a minimum detection limit of 0.017 ppm. At an airflow corresponding to quiet breathing, the ozone generator is capable of producing single boluses with a peak ozone fraction as high as 4 ppm, but containing only 0.35 micrograms of ozone dispersed over a small volume of 19 mL. To test the combination of ozone analyzer and bolus generator, we performed bolus-response experiments at steady airflows of 50 to 200 mL/sec in excised pig and sheep tracheas. In spite of the small surface area available for radial diffusion, we found that 25 to 50 percent of the ozone introduced into the trachea was absorbed. By comparing the mathematical moments of the bolus input and the response curves to the predictions of a diffusion theory, we computed an absorption coefficient (K). The values of K increased with increasing airflow, implying that ozone absorption is limited by diffusion processes in the airway lumen as well as in the surrounding tissue.

Preferential action of arsenic trioxide in solid-tumor microenvironment enhances radiation therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffin, Robert J.; Williams, Brent W.; Park, Heon Joo

2005-04-01

Purpose: To investigate the effect of arsenic trioxide, Trisenox (TNX), on primary cultures of endothelial cells and tumor tissue under varying pH and pO{sub 2} environments and the effects of combined TNX and radiation therapy on experimental tumors. Methods and Materials: Human dermal microvascular endothelial cells were cultured in vitro and exposed to TNX under various combinations of aerobic, hypoxic, neutral, or acidic conditions, and levels of activated JNK MAP kinase were assessed by Western blotting. FSaII fibrosarcoma cells grown in the hind limb of female C3H mice were used to study the effect of TNX on tumor blood perfusionmore » and oxygenation. The tumor-growth delay after a single or fractionated irradiation with or without TNX treatment was assessed. Results: A single intraperitoneal injection of 8 mg/kg TNX reduced the blood perfusion in FSaII tumors by 53% at 2 hours after injection. To increase the oxygenation of the tumor vasculature during TNX treatment, some animals were allowed to breathe carbogen (95% O{sub 2}/5% CO{sub 2}). Carbogen breathing alone for 2 hours reduced tumor perfusion by 33%. When carbogen breathing was begun immediately after TNX injection, no further reduction occurred in tumor blood perfusion at 2 hours after injection. In vitro, TNX exposure increased activity JNK MAP kinase preferentially in endothelial cells cultured in an acidic or hypoxic environment. In vivo, the median oxygenation in FSaII tumors measured at 3 or 5 days after TNX injection was found to be significantly elevated compared with control tumors. Subsequently, radiation-induced tumor-growth delay was synergistically increased when radiation and TNX injection were fractionated at 3-day or 5-day intervals. Conclusions: Trisenox has novel vascular-damaging properties, preferentially against endothelium in regions of low pH or pO{sub 2}, which leads to tumor cell death and enhancement of the response of tumors to radiotherapy.« less

Free-breathing cine DENSE MRI using phase cycling with matchmaking and stimulated-echo image-based navigators.

PubMed

Cai, Xiaoying; Epstein, Frederick H

2018-04-01

This study aimed to develop a self-navigated method for free-breathing spiral cine displacement encoding with stimulated echoes (DENSE), a myocardial strain imaging technique that uses phase-cycling for artifact suppression. The method needed to address 2 consequences of motion for DENSE: striping artifacts from incomplete suppression of the T 1 -relaxation echo and blurring. The method identifies phase-cycled spiral interleaves at matched respiratory phases by minimizing the residual signal due to T 1 relaxation after phase-cycling subtraction. Next, the method reconstructs image-based navigators from matched phase-cycled interleaves that are comprised of the stimulated echo (ste-iNAVs). Ste-iNAVs are used for motion estimation and compensation of k-space data. The method was demonstrated in phantoms and compared to diaphragm-based navigator (dNAV) and conventional iNAV (c-iNAV) methods for the reconstruction of free-breathing volunteer data sets (N = 10). Phantom experiments demonstrated that the proposed method removes striping artifacts and blurring due to motion. Volunteer results showed that respiratory motion measured by ste-iNAVs was better correlated than c-iNAVs to dNAV data (R 2  = 0.82 ± 0.03 vs. 0.70 ± 0.05, P < 0.05). Match-making reconstructions of free-breathing data sets achieved lower residual T 1 -relaxation echo energy (1.04 ± 0.01 vs. 1.18 ± 0.04 for dNAV and 1.18 ± 0.03 for c-iNAV, P < 0.05), higher apparent SNR (11.93 ± 1.05 vs. 10.68 ± 1.06 for dNAV and 10.66 ± 0.99 for c-iNAV, P < 0.05), and better phase quality (0.147 ± 0.012 vs. 0.166 ± 0.017 for dNAV, P = 0.06, and 0.168 ± 0.015 for c-iNAV, P < 0.05) than dNAV and c-iNAV methods. For free-breathing cine DENSE, the proposed method addresses both types of breathing-induced artifacts and provides better quality images than conventional dNAV and iNAV methods. © 2018 International Society for Magnetic Resonance in Medicine.

Use of a single ventilator to support 4 patients: laboratory evaluation of a limited concept.

PubMed

Branson, Richard D; Blakeman, Thomas C; Robinson, Bryce Rh; Johannigman, Jay A

2012-03-01

A mass-casualty respiratory failure event where patients exceed available ventilators has spurred several proposed solutions. One proposal is use of a single ventilator to support 4 patients. A ventilator was modified to allow attachment of 4 circuits. Each circuit was connected to one chamber of 2 dual-chambered, test lungs. The ventilator was set at a tidal volume (V(T)) of 2.0 L, respiratory frequency of 10 breaths/min, and PEEP of 5 cm H(2)O. Tests were repeated with pressure targeted breaths at 15 cm H(2)O. Airway pressure, volume, and flow were measured at each chamber. The test lungs were set to simulate 4 patients using combinations of resistance (R) and compliance (C). These included equivalent C and R, constant R and variable C, constant C and variable R, and variable C and variable R. When R and C were equivalent the V(T) distributed to each chamber of the test lung was similar during both volume (range 428-442 mL) and pressure (range 528-544 mL) breaths. Changing C while R was constant resulted in large variations in delivered V(T) (volume range 257-621 mL, pressure range 320-762 mL). Changing R while C was constant resulted in a smaller variation in V(T) (volume range 418-460 mL, pressure range 502-554 mL) compared to only C changes. When R and C were both varied, the range of delivered V(T) in both volume (336-517 mL) and pressure (417-676 mL) breaths was greater, compared to only R changes. Using a single ventilator to support 4 patients is an attractive concept; however, the V(T) cannot be controlled for each subject and V(T) disparity is proportional to the variability in compliance. Along with other practical limitations, these findings cannot support the use of this concept for mass-casualty respiratory failure.

A Method for Assessing Ground-Truth Accuracy of the 5DCT Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dou, Tai H., E-mail: tdou@mednet.ucla.edu; Thomas, David H.; O'Connell, Dylan P.

2015-11-15

Purpose: To develop a technique that assesses the accuracy of the breathing phase-specific volume image generation process by patient-specific breathing motion model using the original free-breathing computed tomographic (CT) scans as ground truths. Methods: Sixteen lung cancer patients underwent a previously published protocol in which 25 free-breathing fast helical CT scans were acquired with a simultaneous breathing surrogate. A patient-specific motion model was constructed based on the tissue displacements determined by a state-of-the-art deformable image registration. The first image was arbitrarily selected as the reference image. The motion model was used, along with the free-breathing phase information of the originalmore » 25 image datasets, to generate a set of deformation vector fields that mapped the reference image to the 24 nonreference images. The high-pitch helically acquired original scans served as ground truths because they captured the instantaneous tissue positions during free breathing. Image similarity between the simulated and the original scans was assessed using deformable registration that evaluated the pointwise discordance throughout the lungs. Results: Qualitative comparisons using image overlays showed excellent agreement between the simulated images and the original images. Even large 2-cm diaphragm displacements were very well modeled, as was sliding motion across the lung–chest wall boundary. The mean error across the patient cohort was 1.15 ± 0.37 mm, and the mean 95th percentile error was 2.47 ± 0.78 mm. Conclusion: The proposed ground truth–based technique provided voxel-by-voxel accuracy analysis that could identify organ-specific or tumor-specific motion modeling errors for treatment planning. Despite a large variety of breathing patterns and lung deformations during the free-breathing scanning session, the 5-dimensionl CT technique was able to accurately reproduce the original helical CT scans, suggesting its applicability to a wide range of patients.« less

Automated processing of the single-lead electrocardiogram for the detection of obstructive sleep apnoea.

PubMed

de Chazal, Philip; Heneghan, Conor; Sheridan, Elaine; Reilly, Richard; Nolan, Philip; O'Malley, Mark

2003-06-01

A method for the automatic processing of the electrocardiogram (ECG) for the detection of obstructive apnoea is presented. The method screens nighttime single-lead ECG recordings for the presence of major sleep apnoea and provides a minute-by-minute analysis of disordered breathing. A large independently validated database of 70 ECG recordings acquired from normal subjects and subjects with obstructive and mixed sleep apnoea, each of approximately eight hours in duration, was used throughout the study. Thirty-five of these recordings were used for training and 35 retained for independent testing. A wide variety of features based on heartbeat intervals and an ECG-derived respiratory signal were considered. Classifiers based on linear and quadratic discriminants were compared. Feature selection and regularization of classifier parameters were used to optimize classifier performance. Results show that the normal recordings could be separated from the apnoea recordings with a 100% success rate and a minute-by-minute classification accuracy of over 90% is achievable.

Instrumentation development for drug detection on the breath

DOT National Transportation Integrated Search

1972-09-01

Based on a survey of candidate analytical methods, mass spectrometry was identified as a promising technique for drug detection on the breath. To demonstrate its capabilities, an existing laboratory mass spectrometer was modified by the addition of a...

MEASUREMENT METHOD FOR VOLATILE METABOLIC BIOMARKERS IN EXHALED BREATH CONDENSATE

EPA Science Inventory

EPA is developing biomarker methodology to interpret spot biological measurements and their linkage to previous environmental pollutants exposures for individuals. This work explores the use of a promising biological media, exhaled breath condensate (EBC), which contains trapped...

[Examination of gastric emptying rate by means of 13C-octanoic acid breath test. Methods of the test for adults and results of the investigation of healthy volunteers].

PubMed

Bures, J; Kopácová, M; Vorísek, V; Bukac, J; Neumann, D; Rejchrt, S; Pozler, O; Douda, T; Zivný, P; Palicka, V

2005-01-01

13C-octanoic acid breath test (13C-OABT) is a simple, safe and non-invasive technique for measuring gastric emptying. However, the method has not been standardized yet. Aim of the study was to work up, introduce and evaluate our own method of the 13C-OABT for adults. Ten healthy volunteers entered the study (5 men, 5 women, mean age 32 years, 50 % Helicobacter pylori positive). Standard test meals (with 100 mg 13C-sodium octanoate) were used three times within 3 weeks. The same solid meal (1,178 kJ) for Tests 1 and 2 contained scrambled egg (+ 3 g oil), white bread (40 g), butter (10 g) and distilled water (200 ml). Semi-solid meal (1,020 kJ) for Test 3 contained milk pudding (200 g) and distilled water (200 ml). Duplicate breath samples were obtained before and every 15 minutes after eating the test meal during 255 minutes. Altogether 1,080 breath samples were analysed twice (isotope ratio mass spectrometry, AP2003 Analytical Precision, UK). To assess the half-life of elimination (t1/2 E), we modelled the process of elimination with the incomplete gamma-function, which has a convenient form for the empiric plotting of breath test data. Mean t1/2E was 136+/-10 minutes (Test 1), 134+/-14 (Test 2) and 123+/-16 minutes (Test 3). Clinical reproducibility of 13C-OABT in particular persons was 98.2% (18 breath samples series), 90.8 % (15 samples) and 87.1% (9 breath samples series). There was a significant correlation between Test 1 and Test 2 results (r=0.887, p<0.0001). Mean difference of duplicate breath sample analysis was 1.460 % (in 540 pairs), mean baseline one-day analysis difference was 0.0982 (99.9274% accuracy). In healthy volunteers, normal range of t1/2E is 110-160 minutes for solids and 91-155 minutes for semisolid test meal. Using our own computed mean time of intermediate metabolism of 13C-octanoic acid (76.5+/-7.5 minutes), gastric emptying half-time is 33.5-83.5 minutes for solids and 14.5-78.5 minutes for semisolid test meal in healthy volunteers. The 13C-OABT is accurate non-invasive method for gastric emptying measurement.

Combined sensing platform for advanced diagnostics in exhaled mouse breath

NASA Astrophysics Data System (ADS)

Fortes, Paula R.; Wilk, Andreas; Seichter, Felicia; Cajlakovic, Merima; Koestler, Stefan; Ribitsch, Volker; Wachter, Ulrich; Vogt, Josef; Radermacher, Peter; Carter, Chance; Raimundo, Ivo M.; Mizaikoff, Boris

2013-03-01

Breath analysis is an attractive non-invasive strategy for early disease recognition or diagnosis, and for therapeutic progression monitoring, as quantitative compositional analysis of breath can be related to biomarker panels provided by a specific physiological condition invoked by e.g., pulmonary diseases, lung cancer, breast cancer, and others. As exhaled breath contains comprehensive information on e.g., the metabolic state, and since in particular volatile organic constituents (VOCs) in exhaled breath may be indicative of certain disease states, analytical techniques for advanced breath diagnostics should be capable of sufficient molecular discrimination and quantification of constituents at ppm-ppb - or even lower - concentration levels. While individual analytical techniques such as e.g., mid-infrared spectroscopy may provide access to a range of relevant molecules, some IR-inactive constituents require the combination of IR sensing schemes with orthogonal analytical tools for extended molecular coverage. Combining mid-infrared hollow waveguides (HWGs) with luminescence sensors (LS) appears particularly attractive, as these complementary analytical techniques allow to simultaneously analyze total CO2 (via luminescence), the 12CO2/13CO2 tracer-to-tracee (TTR) ratio (via IR), selected VOCs (via IR) and O2 (via luminescence) in exhaled breath, yet, establishing a single diagnostic platform as both sensors simultaneously interact with the same breath sample volume. In the present study, we take advantage of a particularly compact (shoebox-size) FTIR spectrometer combined with novel substrate-integrated hollow waveguide (iHWG) recently developed by our research team, and miniaturized fiberoptic luminescence sensors for establishing a multi-constituent breath analysis tool that is ideally compatible with mouse intensive care stations (MICU). Given the low tidal volume and flow of exhaled mouse breath, the TTR is usually determined after sample collection via gas chromatography coupled to mass spectrometric detection. Here, we aim at potentially continuously analyzing the TTR via iHWGs and LS flow-through sensors requiring only minute (< 1 mL) sample volumes. Furthermore, this study explores non-linearities observed for the calibration functions of 12CO2 and 13CO2 potentially resulting from effects related to optical collision diameters e.g., in presence of molecular oxygen. It is anticipated that the simultaneous continuous analysis of oxygen via LS will facilitate the correction of these effects after inclusion within appropriate multivariate calibration models, thus providing more reliable and robust calibration schemes for continuously monitoring relevant breath constituents.

Neck breathing: a form of voluntary respiration for the spine-injured ventilator-dependent quadriplegic child.

PubMed

Gilgoff, I S; Barras, D M; Jones, M S; Adkins, H V

1988-11-01

Children with respirator-dependent quadriplegia because of C-2 spinal cord injuries are now surviving the acute stages of their injury. The major cause of mortality and morbidity in the chronic stage is due to respiratory complications. Surveillance, 24 h/d, is the best way to prevent accidental disconnection of respirator equipment from the patient and its inherent catastrophic consequences. The constant risk of disconnection adds tension to the home environment and takes away from the patient any degree of independence or privacy. Because of this, an alternative method of respiration using neck accessory muscles was developed to restore a patient-controlled, voluntary system of respiration. This method, neck breathing, is described in detail in seven children varying in age from 3 years to 16 years 3 months. All seven patients had complete paralysis of the intercostal muscles and the diaphragm. An eighth patient who was unable to learn the technique is also described. Neck breathing is also compared to glossopharygeal breathing, an alternative method of respiration developed during the polio era.

The influence of dilution on the offline measurement of exhaled nitric oxide.

PubMed

MacBean, Victoria; Pooranampillai, Dharmika; Howard, Catherine; Lunt, Alan; Greenough, Anne

2018-02-26

Measurement of fractional exhaled nitric oxide (FeNO) is used to determine the presence and severity of eosinophilic airway inflammation in asthma and other wheezing illnesses. The gold standard of online measurement during a single prolonged exhalation is not suitable for use in young children. The international guidelines for offline measurements recommend collection of exhaled gas in an appropriate reservoir for later analysis in young children. The apparatus required for gas collection, however, creates dead space within the system, which may result in sample dilution and hence inaccuracy. Our objective was to investigate the effect such dilution might have on the accuracy of offline FeNO by comparing the results to online results. Thirty-five adult subjects without respiratory disease underwent online measurement of FeNO and, thereafter, undertook offline FeNO measurements via exhalation into a collection reservoir using one, five or ten inhalation-exhalation cycles. Fifteen of the subjects also exhaled using the five-breath technique via apparatus with additional dead space. An equation incorporating dead space volume and the number of breaths was used to predict the degree of dilution; the predicted results were compared to the measured results. The median (IQR) FeNO from a one-breath technique (22 (15-28) ppb was not significantly different to online values (19 (12-27) ppb, p  =  1.00), but the results from the five-breath technique (11 (4-19) ppb, p  <  0.0001), the ten-breath technique (6 (4-15) ppb, p  <  0.0001) and the additional dead space experiment (6 (3-8) ppb, p  =  0.0006) were significantly lower than online FeNO. Measured values were consistently significantly different to those predicted by the dilution equation, even when incorporating the exact exhaled volume of gas. Offline FeNO results may be inaccurate when subjects are unable to fill the collection reservoir with a single exhalation, thus the technique may not be suitable for preschool children.

Phase diagram and breathing dynamics of a single red blood cell and a biconcave capsule in dilute shear flow.

PubMed

Yazdani, Alireza Z K; Bagchi, Prosenjit

2011-08-01

We present phase diagrams of the single red blood cell and biconcave capsule dynamics in dilute suspension using three-dimensional numerical simulations. The computational geometry replicates an in vitro linear shear flow apparatus. Our model includes all essential properties of the cell membrane, namely, the resistance against shear deformation, area dilatation, and bending, as well as the viscosity difference between the cell interior and suspending fluids. By considering a wide range of shear rate and interior-to-exterior fluid viscosity ratio, it is shown that the cell dynamics is often more complex than the well-known tank-treading, tumbling, and swinging motion and is characterized by an extreme variation of the cell shape. As a result, it is often difficult to clearly establish whether the cell is swinging or tumbling. Identifying such complex shape dynamics, termed here as "breathing" dynamics, is the focus of this article. During the breathing motion at moderate bending rigidity, the cell either completely aligns with the flow direction and the membrane folds inward, forming two cusps, or it undergoes large swinging motion while deep, craterlike dimples periodically emerge and disappear. At lower bending rigidity, the breathing motion occurs over a wider range of shear rates, and is often characterized by the emergence of a quad-concave shape. The effect of the breathing dynamics on the tank-treading-to-tumbling transition is illustrated by detailed phase diagrams which appear to be more complex and richer than those of vesicles. In a remarkable departure from the vesicle dynamics, and from the classical theory of nondeformable cells, we find that there exists a critical viscosity ratio below which the transition is independent of the viscosity ratio, and dependent on shear rate only. Further, unlike the reduced-order models, the present simulations do not predict any intermittent dynamics of the red blood cells.

Effect of tracheostomy tube on work of breathing: Comparison of pre- and post-decannulation.

PubMed

Villalba, Darío; Feld, Viviana; Leiva, Valeria; Scrigna, Mariana; Distéfano, Eduardo; Pratto, Romina; Rodriguez, Matías; Collins, Jesica; Rocco, Ana; Matesa, Amelia; Rossi, Damián; Areas, Laura; Virgilio, Sacha; Golfarini, Nicolás; Gil-Rosetti, Gregorio; Diaz-Ballve, Pablo; Planells, Fernando

2016-01-01

To describe and compare the work of breathing (WOB) during spontaneous breathing under four conditions: (1) breathing through a tracheostomy tube with an inflated cuff, (2) breathing through the upper airway (UA) with a deflated cuff and occluded tube, (3) breathing through the UA with an occluded cuffless tube, and (4) postdecannulation. Patients who tolerated an occluded cuffless tube were included. Ventilatory variables and esophageal pressure were recorded. The pressure-time product (PTP), PTP/min, and PTP/min/tidal volume (PTP/min/VT) were measured. Each condition was measured for 5 min with a 15 min time interval between evaluations. Quantitative data are expressed as mean ± standard deviation. Single-factor analysis of variance was used, and the Games-Howell test was used for post hoc analysis of comparisons between group means ( P ≤ 0.05). Eight patients were studied under each of the four conditions described above. Statistically significant differences were found for PTP, PTP/min, and PTP/min/VT. In the post hoc analysis for PTP, significant differences among all conditions were found. For PTP/min, there was no significant difference between Conditions 2 and 4 ( P = 0.138), and for PTP/min/VT, there was no significant difference between Conditions 1 and 2 ( P = 0.072) or between Conditions 2 and 3 ( P = 0.106). A trend toward a higher PTP, PTP/min, and PTP/min/VT was observed when breathing through a cuffless tracheostomy tube. The four conditions differed with respect to WOB. Cuff inflation could result in a reduced WOB because there is less dead space. Cuffless tracheostomy tubes generate increased WOB, perhaps due to the material deformity caused by body temperature.

Exposure to potentially toxic hydrocarbons and halocarbons released from the dialyzer and tubing set during hemodialysis.

PubMed

Lee, Hyun Ji Julie; Meinardi, Simone; Pahl, Madeleine V; Vaziri, Nostratola D; Blake, Donald R

2012-10-01

Although much is known about the effect of chronic kidney failure and dialysis on the composition of solutes in plasma, little is known about their impact on the composition of gaseous compounds in exhaled breath. This study was designed to explore the effect of uremia and the hemodialysis (HD) procedure on the composition of exhaled breath. Breath samples were collected from 10 dialysis patients immediately before, during, and after a dialysis session. To determine the potential introduction of gaseous compounds from dialysis components, gasses emitted from dialyzers, tubing set, dialysate, and water supplies were collected. Prospective cohort study. 10 HD patients and 10 age-matched healthy individuals. Predictors include the dialyzers, tubing set, dialysate, and water supplies before, during, and after dialysis. Changes in the composition of exhaled breath. A 5-column/detector gas chromatography system was used to measure hydrocarbon, halocarbon, oxygenate, and alkyl nitrate compounds. Concentrations of 14 hydrocarbons and halocarbons in patients' breath rapidly increased after the onset of the HD treatment. All 14 compounds and 5 others not found in patients' breath were emitted from the dialyzers and tubing sets. Contrary to earlier reports, exhaled breath ethane concentrations in our dialysis patients were virtually unchanged during the HD treatment. Single-center study with a small sample size may limit the generalizability of the findings. The study documented the release of several potentially toxic hydrocarbons and halocarbons to patients from the dialyzer and tubing sets during the HD procedure. Because long-term exposure to these compounds may contribute to the morbidity and mortality in dialysis population, this issue should be considered in the manufacturing of the new generation of dialyzers and dialysis tubing sets. Copyright © 2012 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Breath condensate levels of 8-isoprostane and leukotriene B4 after ozone inhalation are greater in sensitive versus nonsensitive subjects.

PubMed

Alfaro, Mario F; Walby, William F; Adams, William C; Schelegle, Edward S

2007-01-01

Ozone (O3) inhalation induces pulmonary function decrements and inflammation. The present study was designed to determine if a relationship exists between O3 induced pulmonary function changes and the presence of inflammatory markers as measured in exhaled breath condensates (EBCs) obtained from O3-sensitive and nonsensitive human subjects. Eight healthy adult volunteers (4 males/4 females, age 18 to 30 years) were studied, characterized as to their ozone sensitivity and placed into 2 groups (sensitive and nonsensitive) with each group having 2 males and 2 females. Subjects completed a 20-minute EBC collection and pulmonary function test (PFT) prior to a single 60-minute bout of cycle ergometer exercise (V(E) = 50-55 L/min) while breathing filtered air (FA) or 0.35 ppm O3. Subjective symptom scores (SSSs) were collected at 6, 20, 40, and 60 minutes during exposure. An immediate postexposure PFT was performed followed by an EBC collection. Subjective symptom scores, EBCs, and PFTs were collected at 1, 4 and 8 hours post exposure. EBCs were analyzed for prostaglandin E2 (PGE2), leukotriene B4 (LTB4), 8-isoprostane, and total nitric oxide (NO) metabolites (nitrate + nitrite content). Sensitive subjects, breathing O3, had significantly greater functional decrements in PFTs, increased SSSs, and increased rapid shallow breathing as well as elevated levels of 8-isoprostane and LTB4 in EBCs compared to those breathing FA. In addition, there were significant increases in nitrate + nitrite content in both sensitive and nonsensitive subjects breathing O3 compared to FA. These results indicate that sensitive subjects have elevated arachidonic acid metabolites in EBCs compared to nonsensitive subjects after O3 inhalation.

Standardisation and application of the single-breath determination of nitric oxide uptake in the lung.

PubMed

Zavorsky, Gerald S; Hsia, Connie C W; Hughes, J Michael B; Borland, Colin D R; Guénard, Hervé; van der Lee, Ivo; Steenbruggen, Irene; Naeije, Robert; Cao, Jiguo; Dinh-Xuan, Anh Tuan

2017-02-01

Diffusing capacity of the lung for nitric oxide ( D LNO ), otherwise known as the transfer factor, was first measured in 1983. This document standardises the technique and application of single-breath D LNO This panel agrees that 1) pulmonary function systems should allow for mixing and measurement of both nitric oxide (NO) and carbon monoxide (CO) gases directly from an inspiratory reservoir just before use, with expired concentrations measured from an alveolar "collection" or continuously sampled via rapid gas analysers; 2) breath-hold time should be 10 s with chemiluminescence NO analysers, or 4-6 s to accommodate the smaller detection range of the NO electrochemical cell; 3) inspired NO and oxygen concentrations should be 40-60 ppm and close to 21%, respectively; 4) the alveolar oxygen tension ( P AO 2 ) should be measured by sampling the expired gas; 5) a finite specific conductance in the blood for NO (θNO) should be assumed as 4.5 mL·min -1 ·mmHg -1 ·mL -1 of blood; 6) the equation for 1/θCO should be (0.0062· P AO 2 +1.16)·(ideal haemoglobin/measured haemoglobin) based on breath-holding P AO 2 and adjusted to an average haemoglobin concentration (male 14.6 g·dL -1 , female 13.4 g·dL -1 ); 7) a membrane diffusing capacity ratio ( D MNO / D MCO ) should be 1.97, based on tissue diffusivity. Copyright ©ERS 2017.

The effects of locomotor-respiratory coupling on the pattern of breathing in horses.

PubMed Central

Lafortuna, C L; Reinach, E; Saibene, F

1996-01-01

1. To investigate the effect of locomotor activity on the pattern of breathing in quadrupeds, ventilatory response was studied in four healthy horses during horizontal and inclined (7%) treadmill exercise at different velocities (1.4-6.9 m s(-1)) and during chemical stimulation with a rebreathing method. Stride frequency (f(s)) and locomotor-respiratory coupling (LRC) were also simultaneously determined by means of video recordings synchronized with respiratory events. 2. Tidal volume (V(T)) was positively correlated with pulmonary ventilation (V(E)) but significantly different linear regression equations were found between the experimental conditions (P < 0.0001), since the chemical hyperventilation was mainly due to increases in V(T), whereas the major contribution to exercise hyperpnoea came from changes in respiratory frequency (f(R)). 3. The average f(R) at each exercise level was not significantly different from f(S), although there was not always a tight 1:1 LRC. At constant speeds, f(S) was independent of the treadmill slope and hence the greater V(E) during inclined exercise was due to increased V(T). 4. At any ventilatory level, the differences in breathing patterns between locomotion and rebreathing or locomotion at different slopes derived from different set points of the inspiratory off-switch mechanism. 5. The percentage of single breaths entrained with locomotor rhythm rose progressively and significantly with treadmill speed (P < 0.0001) up to a 1:1 LRC and was significantly affected by treadmill slope (P < 0.001). 6. A LRC of 1:1 was systematically observed at canter (10 out of 10 trials) and sometimes at trot (5 out of 14) and it entailed (i) a 4- to 5-fold reduction in both V(T) and f(R) variability, and (ii) a gait-specific phase locking of inspiratory onset during the locomotor cycle. 7. It is concluded that different patterns of breathing are employed during locomotion and rebreathing due to the interference between locomotor and respiratory functions, which may play a role in the optimization and control of exercise ventilation in horses. PMID:9019552

An optimized 13C-urea breath test for the diagnosis of H pylori infection

PubMed Central

Campuzano-Maya, Germán

2007-01-01

AIM: To validate an optimized 13C-urea breath test (13C-UBT) protocol for the diagnosis of H pylori infection that is cost-efficient and maintains excellent diagnostic accuracy. METHODS: 70 healthy volunteers were tested with two simplified 13C-UBT protocols, with test meal (Protocol 2) and without test meal (Protocol 1). Breath samples were collected at 10, 20 and 30 min after ingestion of 50 mg 13C-urea dissolved in 10 mL of water, taken as a single swallow, followed by 200 mL of water (pH 6.0) and a circular motion around the waistline to homogenize the urea solution. Performance of both protocols was analyzed at various cut-off values. Results were validated against the European protocol. RESULTS: According to the reference protocol, 65.7% individuals were positive for H pylori infection and 34.3% were negative. There were no significant differences in the ability of both protocols to correctly identify positive and negative H pylori individuals. However, only Protocol 1 with no test meal achieved accuracy, sensitivity, specificity, positive and negative predictive values of 100%. The highest values achieved by Protocol 2 were 98.57%, 97.83%, 100%, 100% and 100%, respectively. CONCLUSION: A 10 min, 50 mg 13C-UBT with no test meal using a cut-off value of 2-2.5 is a highly accurate test for the diagnosis of H pylori infection at a reduced cost. PMID:17907288

U-2 Pilot Post-Mission Fatigue Questionnaire

DTIC Science & Technology

2014-10-01

conduct missions in a single- seat aircraft at altitudes above 70,000 feet, requiring the pilot to wear a full pressure suit and breathe 100% oxygen...2014 1.0 SUMMARY U-2 pilots routinely conduct missions in a single- seat aircraft at altitudes above 70,000 feet, requiring the pilot to wear a...pilots, the physical discomfort resulting from prolonged immobility in a single- seat aircraft may contribute to subjective pain and fatigue. Prolonged

RECENT DEVELOPMENTS IN EXHALED BREATH ANALYSIS AND HUMAN EXPOSURE ASSESSMENT RESEARCH

EPA Science Inventory

This presentation will explore historical and newly emerging methods for the collection and analysis of exhaled breath for use in environmental exposure assessment studies. We will discuss their applicability and limitations with respect to environmental research. Particular em...

Automatic control of arterial carbon dioxide tension in mechanically ventilated patients.

PubMed

Fernando, Tyrone; Cade, John; Packer, John

2002-12-01

This paper presents a method of controlling the arterial carbon dioxide tension of patients receiving mechanical ventilation. Controlling of the CO2 tension is achieved by regulating the ventilator initiated breath frequency and also volume per breath.

Photoacoustic sensor for VOCs: first step towards a lung cancer breath test

NASA Astrophysics Data System (ADS)

Wolff, Marcus; Groninga, Hinrich G.; Dressler, Matthias; Harde, Hermann

2005-08-01

Development of new optical sensor technologies has a major impact on the progression of diagnostic methods. Specifically, the optical analysis of breath is an extraordinarily promising technique. Spectroscopic sensors for the non-invasive 13C-breath tests (the Urea Breath Test for detection of Helicobacter pylori is most prominent) are meanwhile well established. However, recent research and development go beyond gastroenterological applications. Sensitive and selective detection of certain volatile organic compounds (VOCs) in a patient's breath, could enable the diagnosis of diseases that are very difficult to diagnose with contemporary techniques. For instance, an appropriate VOC biomarker for early-stage bronchial carcinoma (lung cancer) is n-butane (C4H10). We present a new optical detection scheme for VOCs that employs an especially compact and simple set-up based on photoacoustic spectroscopy (PAS). This method makes use of the transformation of absorbed modulated radiation into a sound wave. Employing a wavelength-modulated distributed feedback (DFB) diode laser and taking advantage of acoustical resonances of the sample cell, we performed very sensitive and selective measurements on butane. A detection limit for butane in air in the ppb range was achieved. In subsequent research the sensitivity will be successively improved to match the requirements of the medical application. Upon optimization, our photoacoustic sensor has the potential to enable future breath tests for early-stage lung cancer diagnostics.

Real-time breath analysis with active capillary plasma ionization-ambient mass spectrometry.

PubMed

Bregy, Lukas; Sinues, Pablo Martinez-Lozano; Nudnova, Maryia M; Zenobi, Renato

2014-06-01

On-line analysis of exhaled human breath is a growing area in analytical science, for applications such as fast and non-invasive medical diagnosis and monitoring. In this work, we present a novel approach based on ambient ionization of compounds in breath and subsequent real-time mass spectrometric analysis. We introduce a plasma ionization source for this purpose, which has no need for additional gases, is very small, and is easily interfaced with virtually any commercial atmospheric pressure ionization mass spectrometer (API-MS) without major modifications. If an API-MS instrument exists in a laboratory, the cost to implement this technology is only around [Formula: see text]500, far less than the investment for a specialized mass spectrometric system designed for volatile organic compounds (VOCs) analysis. In this proof-of-principle study we were able to measure mass spectra of exhaled human breath and found these to be comparable to spectra obtained with other electrospray-based methods. We detected over 100 VOCs, including relevant metabolites like fatty acids, with molecular weights extending up to 340 Da. In addition, we were able to monitor the time-dependent evolution of the peaks and show the enhancement of the metabolism after a meal. We conclude that this approach may complement current methods to analyze breath or other types of vapors, offering an affordable option to upgrade any pre-existing API-MS to a real-time breath analyzer.

Obstructive sleep apnea screening by NIRS imaging

NASA Astrophysics Data System (ADS)

Kashefi, Feraydune; Watenpaugh, Donald E.; Liu, Hanli

2007-02-01

This study aimed at determining cerebral hemodynamic parameters in human subjects during breath holding using near infrared spectroscopy (NIRS). Breath holding serves as a method of simulation OSA (Obstructive Sleep Apnea). Data was acquired non-invasively from 40 subjects, twenty OSA sufferers (10 females, 10 males, age 20-70 years), and twenty normal volunteers (10 females, 10 males, age 20-65 years). Measurements were conducted using a LED Imager (LEDI) during breath holding. In comparing OSA subjects with controls during breath holding, a consistent increase or even a decrease in oxy- ([O IIHb]), deoxy- ([HHb]), total hemoglobin ([tHb]) concentrations, and tissue hemoglobin oxygen saturation (SO II) in the regional brain tissue were observed. The LEDI probe consists of 4 sources and 10 detectors serving as 4 sets of 1 source and 4 detectors each. A three wavelength (730, 805, and 850 nm) LED was used and the wavelengths were switched sequentially. The distance between sources and the source-detector separation were 2.5 cm. Data acquisition consisted of three segments, baseline for one minute, followed by a period of breath holding, and then 2 minutes of recovery time. The duration of the breath holding was subject-dependent. Our investigation proves that NIR spectroscopy could be used as a tool for detecting cerebral hemodynamics and also serves as a method of screening patients with OSA.

Additional Value of CH4 Measurement in a Combined 13C/H2 Lactose Malabsorption Breath Test: A Retrospective Analysis

PubMed Central

Houben, Els; De Preter, Vicky; Billen, Jaak; Van Ranst, Marc; Verbeke, Kristin

2015-01-01

The lactose hydrogen breath test is a commonly used, non-invasive method for the detection of lactose malabsorption and is based on an abnormal increase in breath hydrogen (H2) excretion after an oral dose of lactose. We use a combined 13C/H2 lactose breath test that measures breath 13CO2 as a measure of lactose digestion in addition to H2 and that has a better sensitivity and specificity than the standard test. The present retrospective study evaluated the results of 1051 13C/H2 lactose breath tests to assess the impact on the diagnostic accuracy of measuring breath CH4 in addition to H2 and 13CO2. Based on the 13C/H2 breath test, 314 patients were diagnosed with lactase deficiency, 138 with lactose malabsorption or small bowel bacterial overgrowth (SIBO), and 599 with normal lactose digestion. Additional measurement of CH4 further improved the accuracy of the test as 16% subjects with normal lactose digestion and no H2-excretion were found to excrete CH4. These subjects should have been classified as subjects with lactose malabsorption or SIBO. In conclusion, measuring CH4-concentrations has an added value to the 13C/H2 breath test to identify methanogenic subjects with lactose malabsorption or SIBO. PMID:26371034

How to deal with morning bad breath: A randomized, crossover clinical trial

PubMed Central

Oliveira-Neto, Jeronimo M.; Sato, Sandra; Pedrazzi, Vinícius

2013-01-01

Context: The absence of a protocol for the treatment of halitosis has led us to compare mouthrinses with mechanical oral hygiene procedures for treating morning breath by employing a hand-held sulfide monitor. Aims: To compare the efficacy of five modalities of treatment for controlling morning halitosis in subjects with no dental or periodontal disease. Settings and Design: This is a five-period, randomized, crossover clinical trial. Materials and Methods: Twenty volunteers were randomly assigned to the trial. Testing involved the use of a conventional tongue scraper, a tongue scraper joined to the back of a toothbrush's head, two mouthrinses (0.05% cetylpyridinium chloride and 0.12% chlorhexidine digluconate) and a soft-bristled toothbrush and fluoride toothpaste for practicing oral hygiene. Statistical Analysis Used: Data analysis was performed using SPSS version 17 for Windows and NCSS 2007 software (P < 0.05). The products and the periods were compared with each other using the Friedman's test. When significant differences (P < 0.05) were determined, the products and periods were compared in pairs by using the Wilcoxon's test and by adjusting the original significance level (0.05) for multiple comparisons by using the Bonferroni's method. Results: The toothbrush's tongue scraper was able to significantly reduce bad breath for up to 2 h. Chlorhexidine reduced bad breath only at the end of the second hour, an effect that lasted for 3 h. Conclusions: Mechanical tongue cleaning was able to immediately reduce bad breath for a short period, whereas chlorhexidine and mechanical oral hygiene reduced bad breath for longer periods, achieving the best results against morning breath. PMID:24554886

Fast and Accurate Exhaled Breath Ammonia Measurement

PubMed Central

Solga, Steven F.; Mudalel, Matthew L.; Spacek, Lisa A.; Risby, Terence H.

2014-01-01

This exhaled breath ammonia method uses a fast and highly sensitive spectroscopic method known as quartz enhanced photoacoustic spectroscopy (QEPAS) that uses a quantum cascade based laser. The monitor is coupled to a sampler that measures mouth pressure and carbon dioxide. The system is temperature controlled and specifically designed to address the reactivity of this compound. The sampler provides immediate feedback to the subject and the technician on the quality of the breath effort. Together with the quick response time of the monitor, this system is capable of accurately measuring exhaled breath ammonia representative of deep lung systemic levels. Because the system is easy to use and produces real time results, it has enabled experiments to identify factors that influence measurements. For example, mouth rinse and oral pH reproducibly and significantly affect results and therefore must be controlled. Temperature and mode of breathing are other examples. As our understanding of these factors evolves, error is reduced, and clinical studies become more meaningful. This system is very reliable and individual measurements are inexpensive. The sampler is relatively inexpensive and quite portable, but the monitor is neither. This limits options for some clinical studies and provides rational for future innovations. PMID:24962141

A nanomaterial-based breath test for distinguishing gastric cancer from benign gastric conditions.

PubMed

Xu, Z-q; Broza, Y Y; Ionsecu, R; Tisch, U; Ding, L; Liu, H; Song, Q; Pan, Y-y; Xiong, F-x; Gu, K-s; Sun, G-p; Chen, Z-d; Leja, M; Haick, H

2013-03-05

Upper digestive endoscopy with biopsy and histopathological evaluation of the biopsy material is the standard method for diagnosing gastric cancer (GC). However, this procedure may not be widely available for screening in the developing world, whereas in developed countries endoscopy is frequently used without major clinical gain. There is a high demand for a simple and non-invasive test for selecting the individuals at increased risk that should undergo the endoscopic examination. Here, we studied the feasibility of a nanomaterial-based breath test for identifying GC among patients with gastric complaints. Alveolar exhaled breath samples from 130 patients with gastric complaints (37 GC/32 ulcers / 61 less severe conditions) that underwent endoscopy/biopsy were analyzed using nanomaterial-based sensors. Predictive models were built employing discriminant factor analysis (DFA) pattern recognition, and their stability against possible confounding factors (alcohol/tobacco consumption; Helicobacter pylori) was tested. Classification success was determined (i) using leave-one-out cross-validation and (ii) by randomly blinding 25% of the samples as a validation set. Complementary chemical analysis of the breath samples was performed using gas chromatography coupled with mass spectrometry. Three DFA models were developed that achieved excellent discrimination between the subpopulations: (i) GC vs benign gastric conditions, among all the patients (89% sensitivity; 90% specificity); (ii) early stage GC (I and II) vs late stage (III and IV), among GC patients (89% sensitivity; 94% specificity); and (iii) ulcer vs less severe, among benign conditions (84% sensitivity; 87% specificity). The models were insensitive against the tested confounding factors. Chemical analysis found that five volatile organic compounds (2-propenenitrile, 2-butoxy-ethanol, furfural, 6-methyl-5-hepten-2-one and isoprene) were significantly elevated in patients with GC and/or peptic ulcer, as compared with less severe gastric conditions. The concentrations both in the room air and in the breath samples were in the single p.p.b.v range, except in the case of isoprene. The preliminary results of this pilot study could open a new and promising avenue to diagnose GC and distinguish it from other gastric diseases. It should be noted that the applied methods are complementary and the potential marker compounds identified by gas-chromatography/mass spectrometry are not necessarily responsible for the differences in the sensor responses. Although this pilot study does not allow drawing far-reaching conclusions, the encouraging preliminary results presented here have initiated a large multicentre clinical trial to confirm the observed patterns for GC and benign gastric conditions.

Nondispersive infrared spectrometry for 13CO2/12CO2-measurements: a clinically feasible analyzer for stable isotope breath tests in gastroenterology.

PubMed

Braden, B; Caspary, W F; Lembcke, B

1999-06-01

13C-urea breath tests have become clinical routine for the diagnosis of Helicobacter pylori infection and other isotope breath tests have been invented e.g. for gastric emptying or quantitative liver function testing. Recently, isotope-selective nondispersive infrared spectrometers (NDIRS) have been developed for the analysis of the 13CO2/12CO2-enrichment in breath. In this study, we prospectively tested the validity of a newly developed NDIRS in comparison to isotope ratio mass spectrometry (IRMS). 142 patients with dyspeptic symptoms were tested for Helicobacter pylori infection using the 13C-urea breath test. The isotope ratio analysis of the breath samples was performed in duplicate both using IRMS and NDIRS. The results of the baseline-corrected 13CO2-exhalation values between IRMS and NDIRS were in excellent agreement. The mean difference between both methods was 0.28 +/- 1.93 delta/1000. Evaluating the qualitative urea breath test results in reference to IRMS as the reference the NDIRS had a sensitivity of 97.8% and a specificity of 98.9%. The isotope-selective nondispersive infrared spectroscopy is going to become a reliable, but low-cost and easy-to-operate alternative to expensive isotope ratio mass spectrometry in the analysis of 13C-breath tests.

Utility of Deep Inspiration Breath Hold for Left-Sided Breast Radiation Therapy in Preventing Early Cardiac Perfusion Defects: A Prospective Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zagar, Timothy M., E-mail: zagar@med.unc.edu; Kaidar-Person, Orit; Tang, Xiaoli

Purpose: To evaluate early cardiac single photon computed tomography (SPECT) findings after left breast/chest wall postoperative radiation therapy (RT) in the setting of deep inspiration breath hold (DIBH). Methods and Materials: We performed a prospective single-institution single-arm study of patients who were planned for tangential RT with DIBH to the left breast/chest wall (± internal mammary nodes). The DIBH was done by use of a controlled surface monitoring technique (AlignRT, Vision RT Ltd, London, UK). The RT was given with tangential fields and a heart block. Radiation-induced cardiac perfusion and wall motion changes were assessed by pre-RT and 6-month post-RTmore » SPECT scans. A cumulative SPECT summed-rest score was used to quantify perfusion in predefined left ventricle segments. The incidence of wall motion abnormalities was assessed in each of these same segments. Results: A total of 20 patients with normal pre-RT scans were studied; their median age was 56 years (range, 39-72 years). Seven (35%) patients also received irradiation to the left internal mammary chain, and 5 (25%) received an additional RT field to supraclavicular nodes. The median heart dose was 94 cGy (range, 56-200 cGy), and the median V25{sub Gy} was zero (range, 0-0.1). None of the patients had post-RT perfusion or wall motion abnormalities. Conclusions: Our results suggest that DIBH and conformal cardiac blocking for patients receiving tangential RT for left-sided breast cancer is an effective means to avoid early RT-associated cardiac perfusion defects.« less

ENHANCED CONCENTRATION AND ANALYSIS METHOD FOR MEASURING WATER SOLUABLE ENDOGENOUS COMPOUNDS IN HUMAN BREATH

EPA Science Inventory

Exhaled human breath analysis has become a standard technique for assessing exposure to exogenous volatile organic compounds (VOCs) such as trihalomethanes from water chlorination; aromatics, hydrocarbons, and oxygenates from fuels usage; and various chlorinated solvents from i...

NONINVASIVE APPROACHES FOR TOXICOLOICAL RESEARCH OF THE LUNG

EPA Science Inventory

Four presentations are planned to overview this topic: 1) a review of gas chromatographic and mass spectrometric methods and sensitivity of these measures of volatile molecules present in exhaled breath. Molecular species present in breath have been predictive markers in a number...

SU-E-J-158: Audiovisual Biofeedback Reduces Image Artefacts in 4DCT: A Digital Phantom Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pollock, S; Kipritidis, J; Lee, D

2015-06-15

Purpose: Irregular breathing motion has a deleterious impact on 4DCT image quality. The breathing guidance system: audiovisual biofeedback (AVB) is designed to improve breathing regularity, however, its impact on 4DCT image quality has yet to be quantified. The purpose of this study was to quantify the impact of AVB on thoracic 4DCT image quality by utilizing the digital eXtended Cardiac Torso (XCAT) phantom driven by lung tumor motion patterns. Methods: 2D tumor motion obtained from 4 lung cancer patients under two breathing conditions (i) without breathing guidance (free breathing), and (ii) with guidance (AVB). There were two breathing sessions, yieldingmore » 8 tumor motion traces. This tumor motion was synchronized with the XCAT phantom to simulate 4DCT acquisitions under two acquisition modes: (1) cine mode, and (2) prospective respiratory-gated mode. Motion regularity was quantified by the root mean square error (RMSE) of displacement. The number of artefacts was visually assessed for each 4DCT and summed up for each breathing condition. Inter-session anatomic reproducibility was quantified by the mean absolute difference (MAD) between the Session 1 4DCT and Session 2 4DCT. Results: AVB improved tumor motion regularity by 30%. In cine mode, the number of artefacts was reduced from 61 in free breathing to 40 with AVB, in addition to AVB reducing the MAD by 34%. In gated mode, the number of artefacts was reduced from 63 in free breathing to 51 with AVB, in addition to AVB reducing the MAD by 23%. Conclusion: This was the first study to compare the impact of breathing guidance on 4DCT image quality compared to free breathing, with AVB reducing the amount of artefacts present in 4DCT images in addition to improving inter-session anatomic reproducibility. Results thus far suggest that breathing guidance interventions could have implications for improving radiotherapy treatment planning and interfraction reproducibility.« less

Real-time 3D visualization of the thoraco-abdominal surface during breathing with body movement and deformation extraction.

PubMed

Povšič, K; Jezeršek, M; Možina, J

2015-07-01

Real-time 3D visualization of the breathing displacements can be a useful diagnostic tool in order to immediately observe the most active regions on the thoraco-abdominal surface. The developed method is capable of separating non-relevant torso movement and deformations from the deformations that are solely related to breathing. This makes it possible to visualize only the breathing displacements. The system is based on the structured laser triangulation principle, with simultaneous spatial and color data acquisition of the thoraco-abdominal region. Based on the tracking of the attached passive markers, the torso movement and deformation is compensated using rigid and non-rigid transformation models on the three-dimensional (3D) data. The total time of 3D data processing together with visualization equals 20 ms per cycle.In vitro verification of the rigid movement extraction was performed using the iterative closest point algorithm as a reference. Furthermore, a volumetric evaluation on a live subject was performed to establish the accuracy of the rigid and non-rigid model. The root mean square deviation between the measured and the reference volumes shows an error of  ±0.08 dm(3) for rigid movement extraction. Similarly, the error was calculated to be  ±0.02 dm(3) for torsional deformation extraction and  ±0.11 dm(3) for lateral bending deformation extraction. The results confirm that during the torso movement and deformation, the proposed method is sufficiently accurate to visualize only the displacements related to breathing. The method can be used, for example, during the breathing exercise on an indoor bicycle or a treadmill.

Prospective targeting and control of end-tidal CO2 and O2 concentrations

PubMed Central

Slessarev, Marat; Han, Jay; Mardimae, Alexandra; Prisman, Eitan; Preiss, David; Volgyesi, George; Ansel, Cliff; Duffin, James; Fisher, Joseph A

2007-01-01

Current methods of forcing end-tidal PCO2 (PETCO2) and PO2 (PETO2) rely on breath-by-breath adjustment of inspired gas concentrations using feedback loop algorithms. Such servo-control mechanisms are complex because they have to anticipate and compensate for the respiratory response to a given inspiratory gas concentration on a breath-by-breath basis. In this paper, we introduce a low gas flow method to prospectively target and control PETCO2 and PETO2 independent of each other and of minute ventilation in spontaneously breathing humans. We used the method to change PETCO2 from control (40 mmHg for PETCO2 and 100 mmHg for PETO2) to two target PETCO2 values (45 and 50 mmHg) at iso-oxia (100 mmHg), PETO2 to two target values (200 and 300 mmHg) at normocapnia (40 mmHg), and PETCO2 with PETO2 simultaneously to the same targets (45 with 200 mmHg and 50 with 300 mmHg). After each targeted value, PETCO2 and PETO2 were returned to control values. Each state was maintained for 30 s. The average difference between target and measured values for PETCO2 was ± 1 mmHg, and for PETO2 was ± 4 mmHg. PETCO2 varied by ± 1 mmHg and PETO2 by ± 5.6 mmHg (s.d.) over the 30 s stages. This degree of control was obtained despite considerable variability in minute ventilation between subjects (± 7.6 l min−1). We conclude that targeted end-tidal gas concentrations can be attained in spontaneously breathing subjects using this prospective, feed-forward, low gas flow system. PMID:17446225

SU-E-T-247: Determinations of the Optimal Phase for Respiratory Gated Radiotherapy From Statistical Analysis Using a Visible Guidance System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oh, S; Yea, J; Kang, M

Purpose: Respiratory gated radiation therapy (RGRT) is used to minimize the radiation dose to normal tissue in lung cancer patients. Determination of the optimal point in the respiratory phase of a patient is important in RGRT but it is not easy. The goal of the present study was to see if a visible guidance system is helpful in determining the optimal phase in respiratory gated therapy. Methods: The breathing signals of 23 lung cancer patients were recorded with a Real-time Position Management (RPM) respiratory gating system (Varian, USA). The patients underwent breathing training with our visible guidance system, after whichmore » their breathing signals were recorded during 5 min of free breathing and 5 min of guided breathing. The breathing signals recorded between 3 and 5 min before and after training were compared. We performed statistical analysis of the breathing signals to find the optimal duty cycle in guided breathing for RGRT. Results: The breathing signals aided by the visible guidance system had more regular cycles over time and smaller variations in the positions of the marker block than the free breathing signals. Of the 23 lung cancer patients, 19 showed statistically significant differences by time when the values obtained before and after breathing were compared (p < 0.05); 30% and 40% of the duty cycle, respectively, was determined to be the most effective, and the corresponding phases were 30 60% (duty cycle, 30%; p < 0.05) and 30 70% (duty cycle, 40%; p < 0.05). Conclusion: Respiratory regularity was significantly improved with the use of the RPM with our visible guiding system; therefore, it would help improve the accuracy and efficiency of RGRT.« less

Empirical Equation Based Chirality (n, m) Assignment of Semiconducting Single Wall Carbon Nanotubes from Resonant Raman Scattering Data

PubMed Central

Arefin, Md Shamsul

2012-01-01

This work presents a technique for the chirality (n, m) assignment of semiconducting single wall carbon nanotubes by solving a set of empirical equations of the tight binding model parameters. The empirical equations of the nearest neighbor hopping parameters, relating the term (2n− m) with the first and second optical transition energies of the semiconducting single wall carbon nanotubes, are also proposed. They provide almost the same level of accuracy for lower and higher diameter nanotubes. An algorithm is presented to determine the chiral index (n, m) of any unknown semiconducting tube by solving these empirical equations using values of radial breathing mode frequency and the first or second optical transition energy from resonant Raman spectroscopy. In this paper, the chirality of 55 semiconducting nanotubes is assigned using the first and second optical transition energies. Unlike the existing methods of chirality assignment, this technique does not require graphical comparison or pattern recognition between existing experimental and theoretical Kataura plot. PMID:28348319

Breath Tests in Respiratory and Critical Care Medicine: From Research to Practice in Current Perspectives

PubMed Central

Cheepsattayakorn, Attapon; Cheepsattayakorn, Ruangrong

2013-01-01

Today, exhaled nitric oxide has been studied the most, and most researches have now focusd on asthma. More than a thousand different volatile organic compounds have been observed in low concentrations in normal human breath. Alkanes and methylalkanes, the majority of breath volatile organic compounds, have been increasingly used by physicians as a novel method to diagnose many diseases without discomforts of invasive procedures. None of the individual exhaled volatile organic compound alone is specific for disease. Exhaled breath analysis techniques may be available to diagnose and monitor the diseases in home setting when their sensitivity and specificity are improved in the future. PMID:24151617

Respiratory rate estimation from the built-in cameras of smartphones and tablets.

PubMed

Nam, Yunyoung; Lee, Jinseok; Chon, Ki H

2014-04-01

This paper presents a method for respiratory rate estimation using the camera of a smartphone, an MP3 player or a tablet. The iPhone 4S, iPad 2, iPod 5, and Galaxy S3 were used to estimate respiratory rates from the pulse signal derived from a finger placed on the camera lens of these devices. Prior to estimation of respiratory rates, we systematically investigated the optimal signal quality of these 4 devices by dividing the video camera's resolution into 12 different pixel regions. We also investigated the optimal signal quality among the red, green and blue color bands for each of these 12 pixel regions for all four devices. It was found that the green color band provided the best signal quality for all 4 devices and that the left half VGA pixel region was found to be the best choice only for iPhone 4S. For the other three devices, smaller 50 × 50 pixel regions were found to provide better or equally good signal quality than the larger pixel regions. Using the green signal and the optimal pixel regions derived from the four devices, we then investigated the suitability of the smartphones, the iPod 5 and the tablet for respiratory rate estimation using three different computational methods: the autoregressive (AR) model, variable-frequency complex demodulation (VFCDM), and continuous wavelet transform (CWT) approaches. Specifically, these time-varying spectral techniques were used to identify the frequency and amplitude modulations as they contain respiratory rate information. To evaluate the performance of the three computational methods and the pixel regions for the optimal signal quality, data were collected from 10 healthy subjects. It was found that the VFCDM method provided good estimates of breathing rates that were in the normal range (12-24 breaths/min). Both CWT and VFCDM methods provided reasonably good estimates for breathing rates that were higher than 26 breaths/min but their accuracy degraded concomitantly with increased respiratory rates. Overall, the VFCDM method provided the best results for accuracy (smaller median error), consistency (smaller interquartile range of the median value), and computational efficiency (less than 0.5 s on 1 min of data using a MATLAB implementation) to extract breathing rates that varied from 12 to 36 breaths/min. The AR method provided the least accurate respiratory rate estimation among the three methods. This work illustrates that both heart rates and normal breathing rates can be accurately derived from a video signal obtained from smartphones, an MP3 player and tablets with or without a flashlight.

Applications of absorption spectroscopy using quantum cascade lasers.

PubMed

Zhang, Lizhu; Tian, Guang; Li, Jingsong; Yu, Benli

2014-01-01

Infrared laser absorption spectroscopy (LAS) is a promising modern technique for sensing trace gases with high sensitivity, selectivity, and high time resolution. Mid-infrared quantum cascade lasers, operating in a pulsed or continuous wave mode, have potential as spectroscopic sources because of their narrow linewidths, single mode operation, tunability, high output power, reliability, low power consumption, and compactness. This paper reviews some important developments in modern laser absorption spectroscopy based on the use of quantum cascade laser (QCL) sources. Among the various laser spectroscopic methods, this review is focused on selected absorption spectroscopy applications of QCLs, with particular emphasis on molecular spectroscopy, industrial process control, combustion diagnostics, and medical breath analysis.

Gravitational independence of single-breath washout tests in recumbent dogs

NASA Technical Reports Server (NTRS)

Tomioka, Shinichi; Kubo, Susumu; Guy, Harold J. B.; Prisk, G. K.

1988-01-01

The effect of gravitational orientation in the mechanism of lung filling and emptying in dogs was examined by conducting simultaneously Ar-bolus and N2 single-breath washout tests (SBWTs) in 10 anesthetized dogs (prone and supine), with three of the dogs subjected to body rotation. Transpulmonary pressure was measured simultaneously, allowing identification of the lung volume above residual volume at which there was an inflection point in the pressure-volume curve. Combined resident gas and bolus SBWTs in recumbent dogs were found to be different from such tests in humans; in dogs, the regional distribution of ventilation was not primarily determined by gravity. The measurements did not make it possible to discern exact mechanisms of filling and emptying, but both processes appear to be related to lung, thorax, and mediastinum interactions and/or differences in regional mechanical properties of the lungs.

A Single-Chip CMOS Pulse Oximeter with On-Chip Lock-In Detection.

PubMed

He, Diwei; Morgan, Stephen P; Trachanis, Dimitrios; van Hese, Jan; Drogoudis, Dimitris; Fummi, Franco; Stefanni, Francesco; Guarnieri, Valerio; Hayes-Gill, Barrie R

2015-07-14

Pulse oximetry is a noninvasive and continuous method for monitoring the blood oxygen saturation level. This paper presents the design and testing of a single-chip pulse oximeter fabricated in a 0.35 µm CMOS process. The chip includes photodiode, transimpedance amplifier, analogue band-pass filters, analogue-to-digital converters, digital signal processor and LED timing control. The experimentally measured AC and DC characteristics of individual circuits including the DC output voltage of the transimpedance amplifier, transimpedance gain of the transimpedance amplifier, and the central frequency and bandwidth of the analogue band-pass filters, show a good match (within 1%) with the circuit simulations. With modulated light source and integrated lock-in detection the sensor effectively suppresses the interference from ambient light and 1/f noise. In a breath hold and release experiment the single chip sensor demonstrates consistent and comparable performance to commercial pulse oximetry devices with a mean of 1.2% difference. The single-chip sensor enables a compact and robust design solution that offers a route towards wearable devices for health monitoring.

A Single-Chip CMOS Pulse Oximeter with On-Chip Lock-In Detection

PubMed Central

He, Diwei; Morgan, Stephen P.; Trachanis, Dimitrios; van Hese, Jan; Drogoudis, Dimitris; Fummi, Franco; Stefanni, Francesco; Guarnieri, Valerio; Hayes-Gill, Barrie R.

2015-01-01

Pulse oximetry is a noninvasive and continuous method for monitoring the blood oxygen saturation level. This paper presents the design and testing of a single-chip pulse oximeter fabricated in a 0.35 µm CMOS process. The chip includes photodiode, transimpedance amplifier, analogue band-pass filters, analogue-to-digital converters, digital signal processor and LED timing control. The experimentally measured AC and DC characteristics of individual circuits including the DC output voltage of the transimpedance amplifier, transimpedance gain of the transimpedance amplifier, and the central frequency and bandwidth of the analogue band-pass filters, show a good match (within 1%) with the circuit simulations. With modulated light source and integrated lock-in detection the sensor effectively suppresses the interference from ambient light and 1/f noise. In a breath hold and release experiment the single chip sensor demonstrates consistent and comparable performance to commercial pulse oximetry devices with a mean of 1.2% difference. The single-chip sensor enables a compact and robust design solution that offers a route towards wearable devices for health monitoring. PMID:26184225

Measurement of Respiration Rate and Depth Through Difference in Temperature Between Skin Surface and Nostril by Using Thermal Image.

PubMed

Jeong, Hieyong; Matsuura, Yutaka; Ohno, Yuko

2017-01-01

The purpose of the present study was to propose a method to measure a respiration rate (RR) and depth at once through difference in temperature between the skin surface and nostril by using a thermal image. Although there have been a lot of devices for contact RR monitoring, it was considered that the subjects could be inconvenienced by having the sensing device in contact with their body. Our algorithm enabled us to make a breathing periodic function (BPF) under the non-contact and non-invasive condition through temperature differences near the nostril during the breath. As a result, it was proved that our proposed method was able to classify differences in breathing pattern between normal, deep, and shallow breath (P < 0.001). These results lead us to conclude that the RR and depth is simultaneously measured by the proposed algorithm of BPF without any contact or invasive procedure.

Breathing gas perfluorocarbon measurements using an absorber filled with zeolites.

PubMed

Proquitté, H; Rüdiger, M; Wauer, R R; Schmalisch, G

2003-11-01

Perfluorocarbon (PFC) has been widely used in the treatment of respiratory diseases; however, PFC content of the breathing gases remains unknown. Therefore, we developed an absorber using PFC selective zeolites for PFC measurement in gases and investigated its accuracy. To generate a breathing gas with different PFC contents a heated flask was rinsed with a constant air flow of 4 litre x min(-1) and 1, 5, 10, and 20 ml of PFC were infused over 20 min using an infusor. The absorber was placed on an electronic scale and the total PFC volume was calculated from the weight gain. Steady-state increase in weight was achieved 3.5 min after stopping the infusion. The calculated PFC volume was slightly underestimated but the measuring error did not exceed -1% for PFC less than 1 ml. The measurement error decreased with increasing PFC volume. This zeolite absorber is an accurate method to quantitatively determine PFC in breathing gases and can be used as a reference method to validate other PFC sensors.

Multishot EPI-SSFP in the Heart

PubMed Central

Herzka, Daniel A.; Kellman, Peter; Aletras, Anthony H.; Guttman, Michael A.; McVeigh, Elliot R.

2007-01-01

Refocused steady-state free precession (SSFP), or fast imaging with steady precession (FISP or TrueFISP), has recently proven valuable for cardiac imaging because of its high signal-to-noise ratio (SNR) and excellent blood-myocardium contrast. In this study, various implementations of multiecho SSFP or EPI-SSFP for imaging in the heart are presented. EPI-SSFP has higher scan-time efficiency than single-echo SSFP, as two or more phase-encode lines are acquired per repetition time (TR) at the cost of a modest increase in TR. To minimize TR, a noninterleaved phase-encode order in conjunction with a phased-array ghost elimination (PAGE) technique was employed, removing the need for echo time shifting (ETS). The multishot implementation of EPI-SSFP was used to decrease the breath-hold duration for cine acquisitions or to increase the temporal or spatial resolution for a fixed breath-hold duration. The greatest gain in efficiency was obtained with the use of a three-echo acquisition. Image quality for cardiac cine applications using multishot EPI-SSFP was comparable to that of single-echo SSFP in terms of blood-myocardium contrast and contrast-to-noise ratio (CNR). The PAGE method considerably reduced flow artifacts due to both the inherent ghost suppression and the concomitant reduction in phase-encode blip size. The increased TR of multishot EPI-SSFP led to a reduced specific absorption rate (SAR) for a fixed RF flip angle, and allowed the use of a larger flip angle without increasing the SAR above the FDA-approved limits. PMID:11948726

Cardiac Repolarization Changes in the Children with Breath-Holding Spells

PubMed Central

Amoozgar, Hamid; Saleh, Fazl; Farhani, Nahal; Rafiei, Mohammad; Inaloo, Soroor; Asadipooya, Ali-Akbar

2013-01-01

Objective Breath-holding spells are known as benign attacks, frequencies of which decrease by the development of the autonomic nervous system. The present study aims to compare the electrocardiographic repolarization in children with breath-holding spells. Methods In this study, QT dispersion, QTc dispersion, T peak to T end dispersion, and P wave dispersion of the twelve-lead surface electrocardiography of fifty children who had breath-holding spells were measured and compared with normal children from April 2011 to August 2012. Findings Forty-four (88%) patients had cyanotic spells, while 6 (12%) had pallid spells. QTc dispersion was increased in the patients with breath-holding spells (148.2±33.1) compared to the healthy children (132±27.3) and the difference was statically significant (P = 0.01). Meanwhile, no statistically significant differences were observed between the patients and the control subjects regarding the other parameters (P > 0.05). Conclusion QTc dispersion was significantly increased in the patients with breath-holding spells compared to normal children and this is a sign of cardiac repolarization abnormality as well as the increased risk of cardiac arrhythmia in patients with breath-holding spells. PMID:24910749

Influence of the viscoelastic properties of the respiratory system on the energetically optimum breathing frequency.

PubMed

Bates, J H; Milic-Emili, J

1993-01-01

We hypothesized that the viscoelastic properties of the respiratory system should have significant implications for the energetically optimal frequency of breathing, in view of the fact that these properties cause marked dependencies of overall system resistance and elastance on frequency. To test our hypothesis we simulated two models of canine and human respiratory system mechanics during sinusoidal breathing and calculated the inspiratory work (WI) and pressure-time integral (PTI) per minute under both resting and exercise conditions. The two models were a two-compartment viscoelastic model and a single-compartment model. Requiring minute alveolar ventilation to be fixed, we found that both models predicted almost identical optimum breathing frequencies. The calculated PTI was very insensitive to increases in breathing frequency above the optimal frequencies, while WI was found to increase slowly with frequency above its optimum. In contrast, both WI and PTI increased sharply as frequency decreased below their respective optima. A sensitivity analysis showed that the model predictions were very insensitive to the elastance and resistance values chosen to characterize tissue viscoelasticity. We conclude that the WI criterion for choosing the frequency of breathing is compatible with observations in nature, whereas the optimal frequency predictions of the PTI are rather too high. Both criteria allow for a fairly wide margin of choice in frequency above the optimum values without incurring excessive additional energy expenditure. Furthermore, contrary to our expectations, the viscoelastic properties of the respiratory system tissues do not pose a noticeable problem to the respiratory controller in terms of energy expenditure.

Breath-Hold Diving.

PubMed

Fitz-Clarke, John R

2018-03-25

Breath-hold diving is practiced by recreational divers, seafood divers, military divers, and competitive athletes. It involves highly integrated physiology and extreme responses. This article reviews human breath-hold diving physiology beginning with an historical overview followed by a summary of foundational research and a survey of some contemporary issues. Immersion and cardiovascular adjustments promote a blood shift into the heart and chest vasculature. Autonomic responses include diving bradycardia, peripheral vasoconstriction, and splenic contraction, which help conserve oxygen. Competitive divers use a technique of lung hyperinflation that raises initial volume and airway pressure to facilitate longer apnea times and greater depths. Gas compression at depth leads to sequential alveolar collapse. Airway pressure decreases with depth and becomes negative relative to ambient due to limited chest compliance at low lung volumes, raising the risk of pulmonary injury called "squeeze," characterized by postdive coughing, wheezing, and hemoptysis. Hypoxia and hypercapnia influence the terminal breakpoint beyond which voluntary apnea cannot be sustained. Ascent blackout due to hypoxia is a danger during long breath-holds, and has become common amongst high-level competitors who can suppress their urge to breathe. Decompression sickness due to nitrogen accumulation causing bubble formation can occur after multiple repetitive dives, or after single deep dives during depth record attempts. Humans experience responses similar to those seen in diving mammals, but to a lesser degree. The deepest sled-assisted breath-hold dive was to 214 m. Factors that might determine ultimate human depth capabilities are discussed. © 2018 American Physiological Society. Compr Physiol 8:585-630, 2018. Copyright © 2018 American Physiological Society. All rights reserved.

Measurement of breath acetone in patients referred for an oral glucose tolerance test.

PubMed

Andrews, Brian Terence; Denzer, Wolfgang; Hancock, Gus; Lunn, Dan; Peverall, Robert; Ritchie, Grant; Williams, Karen

2018-04-12

Breath acetone concentrations were measured in 141 subjects (aged 19-91 yrs, mean=59.11yrs standard deviation=12.99yrs), male and female, undergoing an oral glucose tolerance test (OGTT), having been referred to clinic on suspicion of type 2 diabetes. Breath samples were measured using an ion-molecule-reaction mass spectrometer, at the commencement of the OGTT, and after 1 and 2hrs. Subjects were asked to observe the normal routine before and during the OGTT, which includes an overnight fast and ingestion of 75g glucose at the beginning of the routine. Several groups of diagnosis were identified: type 2 Diabetes Mellitus positive (T2DM), n=22; impaired glucose intolerance (IGT), n=33; impaired fasting glucose (IFG), n=14; and reactive hypoglycaemia (RHG), n=5. The subjects with no diagnosis (i.e. normoglycaemia) were used as a control group, n=67. Distributions of breath acetone are presented for the different groups. There was no evidence of a direct relationship between blood glucose and acetone measurements at any time during the study (0hr: p=0.4482; 1hr: p=0.6854; and 2hr: p=0.1858). Nor were there significant differences between the measurements of breath acetone for the control group and the T2DM group (0hr: p=0.1759; 1hr: p=0.4521; and 2hr: p=0.7343). However, the ratio of breath acetone at 1hr to the initial breath acetone was found to be significantly different for the T2DM group compared to both the control and IGT groups (p=0.0189 and 0.011, respectively). The T2DM group was also found to be different in terms of ratio of breath acetone after 1hr to that at 2hrs during the OGTT. And was distinctive in that it showed a significant dependence upon the level of blood glucose at 2hrs (p=0.0146). We conclude that single measurements of the concentrations of breath acetone cannot be used as a potential screening diagnostic for T2DM diabetes in this cohort, but monitoring the evolution of breath acetone could open a non-invasive window to aid in the diagnosis of metabolic conditions. © 2018 IOP Publishing Ltd.

Breath-Figure Self-Assembly, a Versatile Method of Manufacturing Membranes and Porous Structures: Physical, Chemical and Technological Aspects

PubMed Central

2017-01-01

The review is devoted to the physical, chemical, and technological aspects of the breath-figure self-assembly process. The main stages of the process and impact of the polymer architecture and physical parameters of breath-figure self-assembly on the eventual pattern are covered. The review is focused on the hierarchy of spatial and temporal scales inherent to breath-figure self-assembly. Multi-scale patterns arising from the process are addressed. The characteristic spatial lateral scales of patterns vary from nanometers to dozens of micrometers. The temporal scale of the process spans from microseconds to seconds. The qualitative analysis performed in the paper demonstrates that the process is mainly governed by interfacial phenomena, whereas the impact of inertia and gravity are negligible. Characterization and applications of polymer films manufactured with breath-figure self-assembly are discussed. PMID:28813026

Quantitative analysis of the breath-holding half-Fourier acquisition single-shot turbo spin-echo technique in abdominal MRI

NASA Astrophysics Data System (ADS)

Dong, Kyung-Rae; Goo, Eun-Hoe; Lee, Jae-Seung; Chung, Woon-Kwan

2013-01-01

A consecutive series of 50 patients (28 males and 22 females) who underwent hepatic magnetic resonance imaging (MRI) from August to December 2011 were enrolled in this study. The appropriate parameters for abdominal MRI scans were determined by comparing the images (TE = 90 and 128 msec) produced using the half-Fourier acquisition single-shot turbo spin-echo (HASTE) technique at different signal acquisition times. The patients consisted of 15 normal patients, 25 patients with a hepatoma and 10 patients with a hemangioma. The TE in a single patient was set to either 90 msec or 128 msec. This was followed by measurements using the four normal rendering methods of the biliary tract system and the background signal intensity using the maximal signal intensity techniques in the liver, spleen, pancreas, gallbladder, fat, muscles and hemangioma. The signal-to-noise and the contrast-to-noise ratios were obtained. The image quality was assessed subjectively, and the results were compared. The signal-to-noise and the contrast-to-noise ratios were significantly higher at TE = 128 msec than at TE = 90 when diseases of the liver, spleen, pancreas, gallbladder, and fat and muscles, hepatocellular carcinomas and hemangiomas, and rendering the hepatobiliary tract system based on the maximum signal intensity technique were involved (p < 0.05). In addition, the presence of artifacts, the image clarity and the overall image quality were excellent at TE = 128 msec (p < 0.05). In abdominal MRI, the breath-hold half-Fourier acquisition single-shot turbo spin-echo (HASTE) was found to be effective in illustrating the abdominal organs for TE = 128 msec. Overall, the image quality at TE = 128 msec was better than that at TE = 90 msec due to the improved signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Overall, the HASTE technique for abdominal MRI based on a high-magnetic field (3.0 T) at a TE of 128 msec can provide useful data.

A novel 13C-urea breath test device for the diagnosis of Helicobacter pylori infection: continuous online measurements allow for faster test results with high accuracy.

PubMed

Israeli, Eran; Ilan, Yaron; Meir, Shimon Bar; Buenavida, Claudia; Goldin, Eran

2003-08-01

The aim of this study is to determine the accuracy of a novel laptop sized 13C-Urea breath test analyzer that continuously measures expired breath and to use its advantages to decrease testing time. One hundred and eighty-six subjects (mean age of 47.8 years) were tested simultaneously by the BreathID system (Oridion, Israel), and by the traditional IRMS. BreathID continuously measured the expired breath for a ratio of 13CO(2):12CO(2.) This value was expressed as delta over baseline (DOB) and displayed graphically on a screen in real time. One hundred and one subjects were positive and 85 were negative for H. pylori by isotope ratio mass spectrometry (IRMS). The correlation for the BreathID system at 30 minutes was 100% for positive cases and 98% for negative cases. Analysis of the continuous curves generated by the BreathID for all patients permitted definition of different DOB thresholds for a positive or negative result at shorter time intervals. Thus, after 6 minutes a conclusive test result could be obtained for 64% of subjects, and after 10 minutes for 92% of subjects. The 13C-Urea breath test utilizing the technology of molecular correlation spectrometry is an accurate method for determining infection by H. pylori. The advantage of continuous measurements can shorten testing time without compromising accuracy.

The Diagnostic Validity of the 13C-Urea Breath Test in the Gastrectomized Patients: Single Tertiary Center Retrospective Cohort Study

PubMed Central

Kwon, Yong Hwan; Kim, Nayoung; Lee, Ju Yup; Choi, Yoon Jin; Yoon, Kichul; Yoon, Hyuk; Shin, Cheol Min; Park, Young Soo; Lee, Dong Ho

2014-01-01

Background: This study was conducted to evaluate the diagnostic validity of the 13C-urea breath test (13C-UBT) in the remnant stomach after partial gastrectomy for gastric cancer. Methods: The 13C-UBT results after Helicobacter pylori eradication therapy was compared with the results of endoscopic biopsy-based methods in the patients who have received partial gastrectomy for the gastric cancer. Results: Among the gastrectomized patients who showed the positive 13C-UBT results (≥ 2.5‰, n = 47) and negative 13C-UBT results (< 2.5‰, n = 114) after H. pylori eradication, 26 patients (16.1%) and 4 patients (2.5%) were found to show false positive and false negative results based on biopsy-based methods, respectively. The sensitivity, specificity, false positive rate, and false negative rate for the cut-off value of 2.5‰ were 84.0%, 80.9%, 19.1%, and 16.0%, respectively. The positive and negative predictive values were 44.7% and 96.5%, respectively. In the multivariate analysis, two or more H. pylori eradication therapies (odds ratio = 3.248, 95% confidence interval= 1.088–9.695, P = 0.035) was associated with a false positive result of the 13C-UBT. Conclusions: After partial gastrectomy, a discordant result was shown in the positive 13C-UBT results compared to the endoscopic biopsy methods for confirming the H. pylori status after eradication. Additional endoscopic biopsy-based H. pylori tests would be helpful to avoid unnecessary treatment for H. pylori eradication in these cases. PMID:25574466

Aspirin does not affect exercise performance.

PubMed

Roi, G S; Garagiola, U; Verza, P; Spadari, G; Radice, D; Zecca, L; Cerretelli, P

1994-07-01

A single-blind, cross-over study was carried out to evaluate the effects of acetylsalicylic acid (ASA) on cardiorespiratory performance during exercise. Eighteen young men, 9 athletes and 9 untrained but active subjects, performed a progressive maximal exercise test on a cycle ergometer (30 watt, 3 min steps, starting at 60 watt) on three different occasions, after a single administration of plain aspirin (1000mg of ASA), chewable buffered aspirin (1000mg of ASA and 600 mg of calcium carbonate) and placebo. Continuous measurement of breath-by-breath ventilation, oxygen consumption, carbon dioxide output, respiratory frequency and heart rate was carried-out at rest and during the exercise test. Blood lactate concentration was measured just before the start of exercise and at the third minute of each step in order to detect the anaerobic threshold. The pharmacokinetics of aspirin during exercise was also investigated in ten of the eighteen participants. The analysis of all investigated variables did not show any statistically significant difference between treatments, suggesting that a single dose of 1000mg of aspirin does not affect physical performance during submaximal and maximal exercise.

Evaluation of the monitor cursor-line method for measuring pulmonary artery and central venous pressures.

PubMed

Pasion, Editha; Good, Levell; Tizon, Jisebelle; Krieger, Staci; O'Kier, Catherine; Taylor, Nicole; Johnson, Jennifer; Horton, Carrie M; Peterson, Mary

2010-11-01

To determine if the monitor cursor-line feature on bedside monitors is accurate for measuring central venous and pulmonary artery pressures in cardiac surgery patients. Central venous and pulmonary artery pressures were measured via 3 methods (end-expiratory graphic recording, monitor cursor-line display, and monitor digital display) in a convenience sample of postoperative cardiac surgery patients. Pressures were measured twice during both mechanical ventilation and spontaneous breathing. Analysis of variance was used to determine differences between measurement methods and the percentage of monitor pressures that differed by 4 mm Hg or more from the measurement obtained from the graphic recording. Significance level was set at P less than .05. Twenty-five patients were studied during mechanical ventilation (50 measurements) and 21 patients during spontaneous breathing (42 measurements). Measurements obtained via the 3 methods did not differ significantly for either type of pressure (P > .05). Graphically recorded pressures and measurements obtained via the monitor cursor-line or digital display methods differed by 4 mm Hg or more in 4% and 6% of measurements, respectively, during mechanical ventilation and 4% and 11%, respectively, during spontaneous breathing. The monitor cursor-line method for measuring central venous and pulmonary artery pressures may be a reasonable alternative to the end-expiratory graphic recording method in hemodynamically stable, postoperative cardiac surgery patients. Use of the digital display on the bedside monitor may result in larger discrepancies from the graphically recorded pressures than when the cursor-line method is used, particularly in spontaneously breathing patients.

Establishment of a Quick and Highly Accurate Breath Test for ALDH2 Genotyping

PubMed Central

Aoyama, Ikuo; Ohashi, Shinya; Amanuma, Yusuke; Hirohashi, Kenshiro; Mizumoto, Ayaka; Funakoshi, Makiko; Tsurumaki, Mihoko; Nakai, Yukie; Tanaka, Katsuyuki; Hanada, Mariko; Uesaka, Aki; Chiba, Tsutomu; Muto, Manabu

2017-01-01

Objectives: Acetaldehyde, the first metabolite of ethanol, is a definite carcinogen for the esophagus, head, and neck; and aldehyde dehydrogenase 2 (ALDH2) is a mitochondrial enzyme that catalyzes the metabolism of acetaldehyde. The ALDH2 genotype exists as ALDH2*1/*1 (active ALDH2), ALDH2*1/*2 (heterozygous inactive ALDH2), and ALDH2*2/*2 (homozygous inactive ALDH2). Many epidemiological studies have reported that ALDH2*2 carriers are at high risk for esophageal or head and neck squamous cell carcinomas by habitual drinking. Therefore, identification of ALDH2*2 carriers would be helpful for the prevention of those cancers, but there have been no methods suitable for mass screening to identify these individuals. Methods: One hundred and eleven healthy volunteers (ALDH2*1/*1 carriers: 53; ALDH2*1/*2 carriers: 48; and ALDH2*2/*2 carriers: 10) were recruited. Breath samples were collected after drinking 100 ml of 0.5% ethanol using specially designed gas bags, and breath ethanol and acetaldehyde levels were measured by semiconductor gas chromatography. Results: The median (range) breath acetaldehyde levels at 1 min after alcohol ingestion were 96.1 (18.1–399.0) parts per billion (p.p.b.) for the ALDH2*1/*1 genotype, 333.5 (78.4–1218.4) p.p.b. for the ALDH2*1/*2 genotype, and 537.1 (213.2–1353.8) p.p.b. for the ALDH2*2/*2 genotype. The breath acetaldehyde levels in ALDH2*2 carriers were significantly higher than for the ALDH2*1/*1 genotype. Notably, the ratio of breath acetaldehyde level-to-breath ethanol level could identify carriers of the ALDH2*2 allele very accurately (whole accuracy; 96.4%). Conclusions: Our novel breath test is a useful tool for identifying ALDH2*2 carriers, who are at high risk for esophageal and head and neck cancers. PMID:28594397

Effects of Fresh and Aged Vehicular Exhaust Emissions on Breathing Pattern and Cellular Responses – Pilot Single Vehicle Study

PubMed Central

Diaz, Edgar A.; Chung, Yeonseung; Papapostolou, Vasileios; Lawrence, Joy; Long, Mark S.; Hatakeyama, Vivian; Gomes, Brenno; Calil, Yasser; Sato, Rodrigo; Koutrakis, Petros; Godleski, John J.

2013-01-01

The study presented here is a laboratory pilot study using diluted car exhaust from a single vehicle to assess differences in toxicological response between primary emissions and secondary products resulting from atmospheric photochemical reactions of gas phase compounds with O3, OH and other radicals. Sprague-Dawley rats were exposed for five hours to either filtered room air (Sham) or one of two different atmospheres: 1. Diluted Car Exhaust (P) + Mt. Saint Helens Ash (MSHA); 2. P+MSHA+SOA (Secondary Organic Aerosol, formed during simulated photochemical aging of diluted exhaust). Primary and secondary gases were removed using a non-selective diffusion denuder. Continuous respiratory data was collected during the exposure, and broncho-alveolar lavage (BAL) and complete blood counts (CBC) were performed 24 hours after exposure. ANOVA models were used to assess the exposure effect and to compare those effects across different exposure types. Total average exposures were 363±66 μg/m3 P+MSHA and 212±95 μg/m3 P+MSHA+SOA. For both exposures, we observed decreases in breathing rate, tidal and minute volumes (TV, MV) and peak and median flows (PIF, PEF and EF50) along with increases in breathing cycle times (Ti, Te) compared to sham. These results indicate that the animals are changing their breathing pattern with these test atmospheres. Exposure to P+MSHA+SOA produced significant increases in Total Cells, Macrophages and Neutrophils in the BAL and in-vivo chemiluminescence of the lung. There were no significant differences in CBC parameters. Our data suggest that simulated atmospheric photochemistry, producing SOA in the P+MSHA+SOA exposures, enhanced the toxicity of vehicular emissions. PMID:22486346

Effect of a single brushing with two Zn-containing toothpastes on VSC in morning breath: a 12 h, randomized, double-blind, cross-over clinical study.

PubMed

Young, A; Jonski, G

2011-12-01

This randomized, double-blind, 12 h clinical study tested the effect of a single brushing with two Zn-containing toothpastes on volatile sulfur compound (VSC) levels in morning breath. The following toothpastes were each tested by all 28 participants: A-Zn toothpaste, B--experimental toothpaste (Zn citrate + PVM/MA copolymer) and C--control toothpaste without Zn. The evening prior to test days participants brushed their teeth for 2 min with 1 g toothpaste. 12 h later and prior to eating or performing oral hygiene, morning breath levels of VSC (H(2)S, CH(3)SH) were analysed by gas chromatography. Subjects then rinsed for 30 s with 5 ml cysteine and breath samples were analysed for H(2)S (H(2)S(cys)). Median VSC (area under the curve) values were compared for A, B and C and the effects of A and B on VSC were compared with C. Toothpaste B was more effective than both toothpastes A and C in reducing H(2)S, CH(3)SH and H(2)S(cys) (p < 0.05). Compared with toothpaste C, toothpastes A and B reduced H(2)S by 35% and 68%, respectively (p = 0.003), and CH(3)SH by 12% and 47%, respectively (p = 0.002). Toothpaste B reduced H(2)S(cys) by 48% compared with toothpaste C (p = 0.001). It is suggested that the superior effect of the experimental toothpaste was most likely due to a higher Zn concentration combined with longer retention of Zn due to the PVM/MA copolymer.

Effects of fresh and aged vehicular exhaust emissions on breathing pattern and cellular responses--pilot single vehicle study.

PubMed

Diaz, Edgar A; Chung, Yeonseung; Papapostolou, Vasileios; Lawrence, Joy; Long, Mark S; Hatakeyama, Vivian; Gomes, Brenno; Calil, Yasser; Sato, Rodrigo; Koutrakis, Petros; Godleski, John J

2012-04-01

The study presented here is a laboratory pilot study using diluted car exhaust from a single vehicle to assess differences in toxicological response between primary emissions and secondary products resulting from atmospheric photochemical reactions of gas phase compounds with O₃, OH and other radicals. Sprague Dawley rats were exposed for 5 h to either filtered room air (sham) or one of two different atmospheres: (i) diluted car exhaust (P)+Mt. Saint Helens Ash (MSHA); (ii) P+MSHA+secondary organic aerosol (SOA, formed during simulated photochemical aging of diluted exhaust). Primary and secondary gases were removed using a nonselective diffusion denuder. Continuous respiratory data was collected during the exposure, and bronchoalveolar lavage (BAL) and complete blood counts (CBC) were performed 24 h after exposure. ANOVA models were used to assess the exposure effect and to compare those effects across different exposure types. Total average exposures were 363 ± 66 μg/m³ P+MSHA and 212 ± 95 µg/m³ P+MSHA+SOA. For both exposures, we observed decreases in breathing rate, tidal and minute volumes (TV, MV) and peak and median flows (PIF, PEF and EF50) along with increases in breathing cycle times (Ti, Te) compared to sham. These results indicate that the animals are changing their breathing pattern with these test atmospheres. Exposure to P+MSHA+SOA produced significant increases in total cells, macrophages and neutrophils in the BAL and in vivo chemiluminescence of the lung. There were no significant differences in CBC parameters. Our data suggest that simulated atmospheric photochemistry, producing SOA in the P+MSHA+SOA exposures, enhanced the toxicity of vehicular emissions.

24-hour evaluation of dental plaque bacteria and halitosis after consumption of a single placebo or dental treat by dogs.

PubMed

Jeusette, Isabelle C; Román, Aurora Mateo; Torre, Celina; Crusafont, Josep; Sánchez, Nuria; Sánchez, Maria C; Pérez-Salcedo, Leire; Herrera, David

2016-06-01

OBJECTIVE To determine whether consumption of a single dental treat with specific mechanical properties and active ingredients would provide a 24-hour effect on dental plaque bacteria and halitosis in dogs. ANIMALS 10 dogs of various breeds from a privately owned colony that had received routine dental scaling and polishing 4 weeks before the study began. PROCEDURES Dogs were randomly assigned to receive 1 placebo or dental treat first. A 4-week washout period was provided, and then dogs received the opposite treatment. Oral plaque and breath samples were collected before and 0.5, 3, 12, and 24 hours after treat consumption. Volatile sulfur compounds (VSCs) concentration was measured in breath samples. Total aerobic, total anaerobic, Porphyromonas gulae, Prevotella intermedia-like, Tannerella forsythia, and Fusobacterium nucleatum bacterial counts (measured via bacterial culture) and total live bacterial counts, total live and dead bacterial counts, and bacterial vitality (measured via quantitative real-time PCR assay) were assessed in plaque samples. RESULTS Compared with placebo treat consumption, dental treat consumption resulted in a significant decrease in breath VSCs concentration and all plaque bacterial counts, without an effect on bacterial vitality. Effects of the dental treat versus the placebo treat persisted for 12 hours for several bacterial counts and for 24 hours for breath VSCs concentration. CONCLUSIONS AND CLINICAL RELEVANCE Although clinical benefits should be investigated in larger scale, longer-term studies, results of this study suggested that feeding the evaluated dental treat may help to decrease oral bacterial growth in dogs for 12 hours and oral malodor for 24 hours. A feeding interval of 12 hours is therefore recommended.

Interplay effects in proton scanning for lung: a 4D Monte Carlo study assessing the impact of tumor and beam delivery parameters.

PubMed

Dowdell, S; Grassberger, C; Sharp, G C; Paganetti, H

2013-06-21

Relative motion between a tumor and a scanning proton beam results in a degradation of the dose distribution (interplay effect). This study investigates the relationship between beam scanning parameters and the interplay effect, with the goal of finding parameters that minimize interplay. 4D Monte Carlo simulations of pencil beam scanning proton therapy treatments were performed using the 4DCT geometry of five lung cancer patients of varying tumor size (50.4-167.1 cc) and motion amplitude (2.9-30.1 mm). Treatments were planned assuming delivery in 35 × 2.5 Gy(RBE) fractions. The spot size, time to change the beam energy (τes), time required for magnet settling (τss), initial breathing phase, spot spacing, scanning direction, scanning speed, beam current and patient breathing period were varied for each of the five patients. Simulations were performed for a single fraction and an approximation of conventional fractionation. For the patients considered, the interplay effect could not be predicted using the superior-inferior motion amplitude alone. Larger spot sizes (σ ~ 9-16 mm) were less susceptible to interplay, giving an equivalent uniform dose (EUD) of 99.0 ± 4.4% (1 standard deviation) in a single fraction compared to 86.1 ± 13.1% for smaller spots (σ ~ 2-4 mm). The smaller spot sizes gave EUD values as low as 65.3% of the prescription dose in a single fraction. Reducing the spot spacing improved the target dose homogeneity. The initial breathing phase can have a significant effect on the interplay, particularly for shorter delivery times. No clear benefit was evident when scanning either parallel or perpendicular to the predominant axis of motion. Longer breathing periods decreased the EUD. In general, longer delivery times led to lower interplay effects. Conventional fractionation showed significant improvement in terms of interplay, giving a EUD of at least 84.7% and 100.0% of the prescription dose for the small and larger spot sizes respectively. The interplay effect is highly patient specific, depending on the motion amplitude, tumor location and the delivery parameters. Large degradations of the dose distribution in a single fraction were observed, but improved significantly using conventional fractionation.

Interplay effects in proton scanning for lung: A 4D Monte Carlo study assessing the impact of tumor and beam delivery parameters

PubMed Central

Dowdell, S; Grassberger, C; Sharp, G C; Paganetti, H

2013-01-01

Relative motion between a tumor and a scanning proton beam results in a degradation of the dose distribution (interplay effect). This study investigates the relationship between beam scanning parameters and the interplay effect, with the goal of finding parameters that minimize interplay. 4D Monte Carlo simulations of pencil beam scanning proton therapy treatments were performed using the 4DCT geometry of 5 lung cancer patients of varying tumor size (50.4–167.1cc) and motion amplitude (2.9–30.1mm). Treatments were planned assuming delivery in 35×2.5Gy(RBE) fractions. The spot size, time to change the beam energy (τes), time required for magnet settling (τss), initial breathing phase, spot spacing, scanning direction, scanning speed, beam current and patient breathing period were varied for each of the 5 patients. Simulations were performed for a single fraction and an approximation of conventional fractionation. For the patients considered, the interplay effect could not be predicted using the superior-inferior (SI) motion amplitude alone. Larger spot sizes (σ ~9–16mm) were less susceptible to interplay, giving an equivalent uniform dose (EUD) of 99.0±4.4% (1 standard deviation) in a single fraction compared to 86.1±13.1% for smaller spots (σ ~2–4mm). The smaller spot sizes gave EUD values as low as 65.3% of the prescription dose in a single fraction. Reducing the spot spacing improved the target dose homogeneity. The initial breathing phase can have a significant effect on the interplay, particularly for shorter delivery times. No clear benefit was evident when scanning either parallel or perpendicular to the predominant axis of motion. Longer breathing periods decreased the EUD. In general, longer delivery times led to lower interplay effects. Conventional fractionation showed significant improvement in terms of interplay, giving a EUD of at least 84.7% and 100.0% of the prescription dose for the small and larger spot sizes respectively. The interplay effect is highly patient specific, depending on the motion amplitude, tumor location and the delivery parameters. Large degradations of the dose distribution in a single fraction were observed, but improved significantly using conventional fractionation. PMID:23689035

Breath alcohol analysis incorporating standardization to water vapour is as precise as blood alcohol analysis.

PubMed

Grubb, D; Rasmussen, B; Linnet, K; Olsson, S G; Lindberg, L

2012-03-10

A novel breath-alcohol analyzer based on the standardization of the breath alcohol concentration (BrAC) to the alveolar-air water vapour concentration has been developed and evaluated. The present study compares results with this particular breath analyzer with arterial blood alcohol concentrations (ABAC), the most relevant quantitative measure of brain alcohol exposure. The precision of analysis of alcohol in arterial blood and breath were determined as well as the agreement between ABAC and BrAC over time post-dosing. Twelve healthy volunteers were administered 0.6g alcohol/kg bodyweight via an orogastric tube. Duplicate breath and arterial blood samples were obtained simultaneously during the absorption, distribution and elimination phases of the alcohol metabolism with particular emphasis on the absorption phase. The precision of the breath analyzer was similar to the determination of blood alcohol concentration by headspace gas chromatography (CV 2.40 vs. 2.38%, p=0.43). The ABAC/BrAC ratio stabilized 30min post-dosing (2089±99; mean±SD). Before this the BrAC tended to underestimate the coexisting ABAC. In conclusion, breath alcohol analysis utilizing standardization of alcohol to water vapour was as precise as blood alcohol analysis, the present "gold standard" method. The BrAC reliably predicted the coexisting ABAC from 30min onwards after the intake of alcohol. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

The effects of inspiratory diaphragm breathing exercise and expiratory pursed-lip breathing exercise on chronic stroke patients' respiratory muscle activation.

PubMed

Seo, KyoChul; Hwan, Park Seung; Park, KwangYong

2017-03-01

[Purpose] The purpose of this study is to examine the effects of inspiratory diaphragm breathing exercise and expiratory pursed-lip breathing exercise on chronic stroke patients' respiratory muscle activation. [Subjects and Methods] All experimental subjects performed exercises five times per week for four weeks. Thirty chronic stroke patients were randomly assign to an experimental group of 15 patients and a control group of 15 patients. The experimental group underwent exercises consisting of basic exercise treatment for 15 minutes and inspiratory diaphragm breathing exercise and expiratory pursed-lip breathing exercise for 15 minutes and the control group underwent exercises consisting of basic exercise treatment for 15 minutes and auto-med exercise for 15 minutes. The activation levels of respiratory muscles were measured before and after the experiment using MP 150WSW to obtain the results of the experiment. [Results] In the present study, when the pulmonary functions of the experimental group and the control group before and after the experiment were compared, whereas the experimental group showed significant differences in all sections. In the verification of intergroup differences between the experimental group and the control group before and after the experiment. [Conclusion] The respiratory rehabilitation exercise is considered to be capable of inducing positive effects on stroke patients' respiratory muscles through diaphragm breathing exercise and lip puckering breathing exercise.

Direct analysis of human breath ammonia using corona discharge ion mobility spectrometry.

PubMed

Jazan, Elham; Mirzaei, Hadi

2014-01-01

In this study, ammonia in human breath was directly determined using corona discharge ionization ion mobility spectrometry (CD-IMS) technique with several important advantages including high sensitivity, low cost, high speed, and ease of maintenance. The temperature effect on the ammonia signal was evaluated too. The results indicated that the best temperature for the investigation of breath ammonia was 150°C. The analytical results showed that the linear dynamic range was between 12 and 810ppb and the detection limit was 6.6ppb. The relative standard deviation (RSD) was obtained to be 5, 3, and 3 for 290, 348, and 522ppb, respectively. The amounts of ammonia in breath of eight healthy volunteers were measured. The values were between 236 and 1218ppb. Also, the inequality in breath ammonia levels was scrutinized over a 6h working day for three healthy volunteers. The results showed a drop in breath ammonia from the morning amount to the mid-day measurement and then, a progressive increase while the day continued. In addition, the amounts of ammonia were determined to be 1494-1553ppb in exhaled breath of two renal failure patients. The results obtained in this work revealed that the method was conveniently established without any considerable sample pretreatment for direct analysis of ammonia in human breath. Copyright © 2013 Elsevier B.V. All rights reserved.

Feedback linearization for control of air breathing engines

NASA Technical Reports Server (NTRS)

Phillips, Stephen; Mattern, Duane

1991-01-01

The method of feedback linearization for control of the nonlinear nozzle and compressor components of an air breathing engine is presented. This method overcomes the need for a large number of scheduling variables and operating points to accurately model highly nonlinear plants. Feedback linearization also results in linear closed loop system performance simplifying subsequent control design. Feedback linearization is used for the nonlinear partial engine model and performance is verified through simulation.

Proposal of Screening Method of Sleep Disordered Breathing Using Fiber Grating Vision Sensor

NASA Astrophysics Data System (ADS)

Aoki, Hirooki; Nakamura, Hidetoshi; Nakajima, Masato

Every conventional respiration monitoring technique requires at least one sensor to be attached to the body of the subject during measurement, thereby imposing a sense of restraint that results in aversion against measurements that would last over consecutive days. To solve this problem, we developed a respiration monitoring system for sleepers, and it uses a fiber-grating vision sensor, which is a type of active image sensor to achieve non-contact respiration monitoring. In this paper, we verified the effectiveness of the system, and proposed screening method of the sleep disordered breathing. It was shown that our system could equivalently measure the respiration with thermistor and accelerograph. And, the respiratory condition of sleepers can be grasped by our screening method in one look, and it seems to be useful for the support of the screening of sleep disordered breathing.

Optical fiber sensor for breathing diagnostics

NASA Astrophysics Data System (ADS)

Claus, Richard O.; Distler, T.; Mecham, J. B.; Davis, B.; Arregui, F. J.; Matias, I. R.

2004-06-01

We report improvements of an optical fiber-based humidity sensor to the problem of breathing diagnostics. The sensor is fabricated by molecularly self-assembling selected polymers and functionalized inorganic nanoclusters into multilayered optical thin films on the cleaved and polished flat end of a singlemode optical fiber. Recent work has studied the synthesis process and the fundamental mechanisms responsible for the change in optical reflection from such a multicomponent film that occurs as a function of humidity and various chemicals. We briefly review that prior work as a way to introduce more recent developments. The paper then discusses the application of these humidity sensors to the analysis of air flow associated with breathing [1]. We have designed the sensor thin film materials to enable the detection of relative humidity over a wide range, from approximately 5 to 95%, and for response times as short as several microseconds. This fast response time allows the near real-time analysis of air flow and water vapor transport during a single breath, with the advantage of very small size. The use of multiple sensors spaced a known distance apart allows the measurement of flow velocity, and recent work indicates a variation in sensor response versus coating thickness.

Electronic Noses for Well-Being: Breath Analysis and Energy Expenditure

PubMed Central

Gardner, Julian W.; Vincent, Timothy A.

2016-01-01

The wealth of information concealed in a single human breath has been of interest for many years, promising not only disease detection, but also the monitoring of our general well-being. Recent developments in the fields of nano-sensor arrays and MEMS have enabled once bulky artificial olfactory sensor systems, or so-called “electronic noses”, to become smaller, lower power and portable devices. At the same time, wearable health monitoring devices are now available, although reliable breath sensing equipment is somewhat missing from the market of physical, rather than chemical sensor gadgets. In this article, we report on the unprecedented rise in healthcare problems caused by an increasingly overweight population. We first review recently-developed electronic noses for the detection of diseases by the analysis of basic volatile organic compounds (VOCs). Then, we discuss the primary cause of obesity from over eating and the high calorific content of food. We present the need to measure our individual energy expenditure from our exhaled breath. Finally, we consider the future for handheld or wearable devices to measure energy expenditure; and the potential of these devices to revolutionize healthcare, both at home and in hospitals. PMID:27347946

Changes in sitting posture induce multiplanar changes in chest wall shape and motion with breathing.

PubMed

Lee, Linda-Joy; Chang, Angela T; Coppieters, Michel W; Hodges, Paul W

2010-03-31

This study examined the effect of sitting posture on regional chest wall shape in three dimensions, chest wall motion (measured with electromagnetic motion analysis system), and relative contributions of the ribcage and abdomen to tidal volume (%RC/V(t)) (measured with inductance plethysmography) in 7 healthy volunteers. In seven seated postures, increased dead space breathing automatically increased V(t) (to 1.5 V(t)) to match volume between conditions and study the effects of posture independent of volume changes. %RC/V(t) (p<0.05), chest wall shape (p<0.05) and motion during breathing differed between postures. Compared to a reference posture, movement at the 9th rib lateral diameter increased in the thoracolumbar extension posture (p<0.008). In slumped posture movement at the AP diameters at T1 and axilla increased (p<0.00001). Rotation postures decreased movement in the lateral diameter at the axilla (p<0.0007). The data show that single plane changes in sitting posture alter three-dimensional ribcage configuration and chest wall kinematics during breathing, while maintaining constant respiratory function. Copyright 2010 Elsevier B.V. All rights reserved.

Rumination and modes of processing around meal times in women with anorexia nervosa: qualitative and quantitative results from a pilot study.

PubMed

Cowdrey, Felicity A; Stewart, Anne; Roberts, Jill; Park, Rebecca J

2013-09-01

The primary aim of this exploratory study was to examine qualitatively and quantitatively the effects of rumination, mindful breathing, and distraction on processing styles and the meal time experience in women with a history of anorexia nervosa (AN). A quasi-experimental within-participant design was employed. Thirty-seven women with history of AN and all experiencing current eating disorder psychopathology listened to a single rumination, mindful breathing and distraction exercise before a meal time. Qualitative and quantitative analyses were employed. Specific themes were extracted for each exercise including avoidance, being in the moment and rumination. The rumination exercise led to significantly greater analytical self-focus. Mindful breathing led to significantly greater experiential self-focus compared with distraction in partially weight-restored AN participants. In AN, self-material is processed in a ruminative way and avoidance is valued. It is difficult to shift individuals with AN out of a rumination around meal times using brief mindful breathing. Future research should investigate at what stage of AN illness mindful-based and acceptance-based strategies are useful and how these strategies could be incorporated in treatment. Copyright © 2013 John Wiley & Sons, Ltd and Eating Disorders Association.

Accuracy of the dose-shift approximation in estimating the delivered dose in SBRT of lung tumors considering setup errors and breathing motions.

PubMed

Karlsson, Kristin; Lax, Ingmar; Lindbäck, Elias; Poludniowski, Gavin

2017-09-01

Geometrical uncertainties can result in a delivered dose to the tumor different from that estimated in the static treatment plan. The purpose of this project was to investigate the accuracy of the dose calculated to the clinical target volume (CTV) with the dose-shift approximation, in stereotactic body radiation therapy (SBRT) of lung tumors considering setup errors and breathing motion. The dose-shift method was compared with a beam-shift method with dose recalculation. Included were 10 patients (10 tumors) selected to represent a variety of SBRT-treated lung tumors in terms of tumor location, CTV volume, and tumor density. An in-house developed toolkit within a treatment planning system allowed the shift of either the dose matrix or a shift of the beam isocenter with dose recalculation, to simulate setup errors and breathing motion. Setup shifts of different magnitudes (up to 10 mm) and directions as well as breathing with different peak-to-peak amplitudes (up to 10:5:5 mm) were modeled. The resulting dose-volume histograms (DVHs) were recorded and dose statistics were extracted. Generally, both the dose-shift and beam-shift methods resulted in calculated doses lower than the static planned dose, although the minimum (D 98% ) dose exceeded the prescribed dose in all cases, for setup shifts up to 5 mm. The dose-shift method also generally underestimated the dose compared with the beam-shift method. For clinically realistic systematic displacements of less than 5 mm, the results demonstrated that in the minimum dose region within the CTV, the dose-shift method was accurate to 2% (root-mean-square error). Breathing motion only marginally degraded the dose distributions. Averaged over the patients and shift directions, the dose-shift approximation was determined to be accurate to approximately 2% (RMS) within the CTV, for clinically relevant geometrical uncertainties for SBRT of lung tumors.

Molecular and Microscopic Analysis of Bacteria and Viruses in Exhaled Breath Collected Using a Simple Impaction and Condensing Method

PubMed Central

Xu, Zhenqiang; Shen, Fangxia; Li, Xiaoguang; Wu, Yan; Chen, Qi; Jie, Xu; Yao, Maosheng

2012-01-01

Exhaled breath condensate (EBC) is increasingly being used as a non-invasive method for disease diagnosis and environmental exposure assessment. By using hydrophobic surface, ice, and droplet scavenging, a simple impaction and condensing based collection method is reported here. Human subjects were recruited to exhale toward the device for 1, 2, 3, and 4 min. The exhaled breath quickly formed into tiny droplets on the hydrophobic surface, which were subsequently scavenged into a 10 µL rolling deionized water droplet. The collected EBC was further analyzed using culturing, DNA stain, Scanning Electron Microscope (SEM), polymerase chain reaction (PCR) and colorimetry (VITEK 2) for bacteria and viruses. Experimental data revealed that bacteria and viruses in EBC can be rapidly collected using the method developed here, with an observed efficiency of 100 µL EBC within 1 min. Culturing, DNA stain, SEM, and qPCR methods all detected high bacterial concentrations up to 7000 CFU/m3 in exhaled breath, including both viable and dead cells of various types. Sphingomonas paucimobilis and Kocuria variants were found dominant in EBC samples using VITEK 2 system. SEM images revealed that most bacteria in exhaled breath are detected in the size range of 0.5–1.0 µm, which is able to enable them to remain airborne for a longer time, thus presenting a risk for airborne transmission of potential diseases. Using qPCR, influenza A H3N2 viruses were also detected in one EBC sample. Different from other devices restricted solely to condensation, the developed method can be easily achieved both by impaction and condensation in a laboratory and could impact current practice of EBC collection. Nonetheless, the reported work is a proof-of-concept demonstration, and its performance in non-invasive disease diagnosis such as bacterimia and virus infections needs to be further validated including effects of its influencing matrix. PMID:22848436

Speaking-Related Dyspnea in Healthy Adults

ERIC Educational Resources Information Center

Hoit, Jeannette D.; Lansing, Robert W.; Perona, Kristen E.

2007-01-01

Purpose: To reveal the qualities and intensity of speaking-related dyspnea in healthy adults under conditions of high ventilatory drive, in which the behavioral and metabolic control of breathing must compete. Method: Eleven adults read aloud while breathing different levels of inspired carbon dioxide (CO[subscript 2]). After the highest level,…

Application of Novel Method to Measure Endogenous VOCs in Exhaled Breath Condensate Before and After Exposure to Diesel Exhaust

EPA Science Inventory

Polar volatile organic compounds (PVOCs) such as aldehydes, ketones, and alcohols are byproducts of normal human metabolism and are present in exhaled breath and blood. Environmental exposures, individual activities, and disease states can perturb normal metabolic processes and ...

The impact of breathing on HRV measurements: implications for the longitudinal follow-up of athletes.

PubMed

Saboul, Damien; Pialoux, Vincent; Hautier, Christophe

2013-01-01

The purpose of the present work was to compare daily variations of heart rate variability (HRV) parameters between controlled breathing (CB) and spontaneous breathing (SB) sessions during a longitudinal follow-up of athletes. HRV measurements were performed daily on 10 healthy male runners for 21 consecutive days. The signals were recorded during two successive randomised 5-minutes sessions. One session was performed in CB and the other in SB. The results showed significant differences between the two respiration methods in the temporal, nonlinear and frequency domains. However, significant correlations were observed between CB and SB (higher than 0.70 for RMSSD and SD1), demonstrating that during a longitudinal follow-up, these markers provide the same HRV variations regardless of breathing pattern. By contrast, independent day-to-day variations were observed with HF and LF/HF frequency markers, indicating no significant relationship between SB and CB data over time. Therefore, we consider that SB and CB may be used for HRV longitudinal follow-ups only for temporal and nonlinear markers. Indeed, the same daily increases and decreases were observed whatever the breathing method employed. Conversely, frequency markers did not provide the same variations between SB and CB and we propose that these indicators are not reliable enough to be used for day-to-day HRV monitoring.

Cellular respiration: replicating in vivo systems biology for in ...

EPA Pesticide Factsheets

This editorial develops a philosophy for expanding the scope of Journal of Breath Research (JBR) into the realm of cellular level study, and links certain topics back to more traditional systemic research for understanding human health based on exhaled breath constituents. The express purpose is to provide a publication outlet for novel breath related research that includes in vitro studies, especially those that explore the biological origin and expression of compounds that may ultimately influence the constituents of exhaled breath. The new topics include all manner of methods and instrumentations for making in vivo and in vitro measurements, the use of different biological media (blood, urine saliva, swabs) including human and microbial cell-lines, in vitro kinetic studies of metabolism, and advances in ex vivo methods for maintaining metabolic competency and viability of biological samples. Traditionally, JBR has published articles on human breath analysis for diagnosing disease, tracking health state, assessing the dose and effect of exogenous chemicals, and contributions of malodorous compounds from the oral/nasal cavity. These have also included research describing novel sampling and analytical technologies, most notably those implementing mass spectrometry, chemical sensors and optical measurement instrumentation (Amann and Smith 2013). The journal’s original scope has also embraced animal models as surrogates for human sampling, new mathematical and

SU-E-J-136: Evaluation of a Non-Invasive Method on Lung Tumor Tracking.

PubMed

Zhao, T; White, B; Low, D

2012-06-01

to develop a non-invasive method to track lung motion in free-breathing patients. A free-breathing breathing model has been developed to use tidal volume and air flow rate as surrogates for lung trajectories. In this study, 4D CT data sets were acquired during simulation and were reconstructed into 10 phases. Total lung capacities were calculated from the reconstructed images. Continuous signals from the abdominal pneumatic belt were correlated to the volumes and were therefore converted into a curve of tidal volumes. Air flow rate were calculated as the first order derivative of the tidal volume curve. Lung trajectories in the 10 reconstructed images were obtained using B-Spline registration. Parameters of the free-breathing lung motion model were fit from the tidal volumes, airflow rates and lung trajectories using the simulation data. Patients were rescanned every week during the treatment. Prediction of lung trajectories from the model were given and compared to the actual positions in BEV. Trajectories of lung were predicted with residual error of 1.49mm at 95th percentile of all tracked points. Tracking was stable and reproducible over two weeks. Non-invasive tumor tracking based on a free-breathing lung motion model is feasible and stable over weeks. © 2012 American Association of Physicists in Medicine.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubinstein, A; Kingsley, C; Melancon, A

Purpose: To evaluate the use of post-irradiation changes in respiratory rate and CBCT-based morphology as predictors of survival in mice. Methods: C57L/J mice underwent whole-thorax irradiation with a Co-60 beam to four different doses [0Gy (n=3), 9Gy (n=5), 11Gy (n=7), and 13Gy (n=5)] in order to induce varying levels of pneumonitis. Respiratory rate measurements, breath-hold CBCTs, and free-breathing CBCTs were acquired pre-irradiation and at six time points between two and seven months post-irradiation. For respiratory rate measurements, we developed a novel computer-vision-based technique. We recorded mice sleeping in standard laboratory cages with a 30 fps, 1080p webcam (Logitech C920). Wemore » calculated respiratory rate using corner detection and optical flow to track cyclical motion in the fur in the recorded video. Breath-hold and free-breathing CBCTs were acquired on the X-RAD225Cx system. For breathhold imaging, the mice were intubated and their breath was held at full-inhale for 20 seconds. Healthy lung tissue was delineated in the scans using auto-threshold contouring (0–0.7 g/cm{sup 3}). The volume of healthy lung was measured in each of the scans. Next, lung density was measured in a 6-mm{sup 2} ROI in a fixed anatomic location in each of the scans. Results: Day-to-day variability in respiratory rate with our technique was 13%. All metrics except for breath-hold lung volume were correlated with survival: lung density on free-breathing (r=−0.7482,p<0.01) and breath-hold images (r=−0.5864,p<0.01), free-breathing lung volume (r=0.7179,p<0.01), and respiratory rate (r= 0.6953,p<0.01). Lung density on free-breathing scans was correlated with respiratory rate (r=0.7142,p<0.01) and lung density on breath-hold scans (r=0.5543,p<0.01). One significant practical hurdle in the CBCT measurements was that at least one lobe of the lung was collapsed in 36% of free-breathing scans and 45% of breath-hold scans. Conclusion: Lung density and lung volume on free-breathing CBCTs and respiratory rate outperform breath-hold CBCT measurements as indicators for survival from radiation-induced pneumonitis. This work was partially funded by Elekta.« less

Anatomic and Pathologic Variability During Radiotherapy for a Hybrid Active Breath-Hold Gating Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glide-Hurst, Carri K.; Gopan, Ellen; Department of Radiation Oncology Wayne State University, Detroit, MI

2010-07-01

Purpose: To evaluate intra- and interfraction variability of tumor and lung volume and position using a hybrid active breath-hold gating technique. Methods and Materials: A total of 159 repeat normal inspiration active breath-hold CTs were acquired weekly during radiotherapy for 9 lung cancer patients (12-21 scans per patient). A physician delineated the gross tumor volume (GTV), lungs, and spinal cord on the first breath-hold CT, and contours were propagated semiautomatically. Intra- and interfraction variability of tumor and lung position and volume were evaluated. Tumor centroid and border variability were quantified. Results: On average, intrafraction variability of lung and GTV centroidmore » position was <2.0 mm. Interfraction population variability was 3.6-6.7 mm (systematic) and 3.1-3.9 mm (random) for the GTV centroid and 1.0-3.3 mm (systematic) and 1.5-2.6 mm (random) for the lungs. Tumor volume regressed 44.6% {+-} 23.2%. Gross tumor volume border variability was patient specific and demonstrated anisotropic shape change in some subjects. Interfraction GTV positional variability was associated with tumor volume regression and contralateral lung volume (p < 0.05). Inter-breath-hold reproducibility was unaffected by time point in the treatment course (p > 0.1). Increases in free-breathing tidal volume were associated with increases in breath-hold ipsilateral lung volume (p < 0.05). Conclusions: The breath-hold technique was reproducible within 2 mm during each fraction. Interfraction variability of GTV position and shape was substantial because of tumor volume and breath-hold lung volume change during therapy. These results support the feasibility of a hybrid breath-hold gating technique and suggest that online image guidance would be beneficial.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thrall, Karla D.; Schwartz, Ronald E.; Weitz, Karl K.

Nasal dosimetry models have become increasingly quantitative as insights into tissue deposition/clearance and computational fluid dynamics have become available. Validation of these models requires sufficient experimental data. However, investigations into respiratory deposition, particularly in human volunteers, have been historically limited due to methodological limitations. To overcome this, a method for evaluating the nasal wash-in, wash-out phenomena of a highly water-soluble compound in human volunteers was developed and characterized. This methodology was assessed using controlled human inhalation exposures to uniformly labeled 13C-acetone at approximately 1 ppm concentration for 30 minutes under different breathing maneuvers (inhale nose/exhale nose; inhale nose/exhale mouth; inhalemore » mouth/exhale nose). A small-diameter air-sampling probe inserted in the nasopharyngeal cavity of the volunteer was connected directly to an ion-trap mass spectrometer capable of sampling every 0.8 sec. A second ion-trap mass spectrometer simultaneously sampled from the volunteer?s exhaled breath stream via a breath-inlet device interface. Together, the two mass spectrometers provided real-time appraisal of the 13C-acetone concentrations in the nasopharyngeal region and in the exhaled breath stream before, during, and after the different breathing maneuvers. The breathing cycle (depth and frequency) and heart rate were concurrently monitored throughout the exposure using a heart rate monitor and a human plethysmograph to differentiate inhalation and exhalation. Graphical overlay of the plethysmography results with the mass spectrometer measurements show clear quantifiable differences in 13C-acetone levels at the nasal probe as a function of breathing maneuvers. Breath-by-breath analysis of 13C-acetone concentrations indicate that between 40-75% of the compound is absorbed upon inhalation and nearly all of that absorbed released back into the breath stream during exhalation.« less

Inhaled Hydrogen Sulfide

PubMed Central

Volpato, Gian Paolo; Searles, Robert; Yu, Binglan; Scherrer-Crosbie, Marielle; Bloch, Kenneth D.; Ichinose, Fumito; Zapol, Warren M.

2010-01-01

Background Breathing hydrogen sulfide (H2S) has been reported to induce a suspended animation–like state with hypothermia and a concomitant metabolic reduction in rodents. However, the impact of H2S breathing on cardiovascular function remains incompletely understood. In this study, the authors investigated the cardiovascular and metabolic effects of inhaled H2S in a murine model. Methods The impact of breathing H2S on cardiovascular function was examined using telemetry and echocardiography in awake mice. The effects of breathing H2S on carbon dioxide production and oxygen consumption were measured at room temperature and in a warmed environment. Results Breathing H2S at 80 parts per million by volume at 27°C ambient temperature for 6 h markedly reduced heart rate, core body temperature, respiratory rate, and physical activity, whereas blood pressure remained unchanged. Echocardiography demonstrated that H2S exposure decreased both heart rate and cardiac output but preserved stroke volume. Breathing H2S for 6 h at 35°C ambient temperature (to prevent hypothermia) decreased heart rate, physical activity, respiratory rate, and cardiac output without altering stroke volume or body temperature. H2S breathing seems to induce bradycardia by depressing sinus node activity. Breathing H2S for 30 min decreased whole body oxygen consumption and carbon dioxide production at either 27° or 35°C ambient temperature. Both parameters returned to baseline levels within 10 min after the cessation of H2S breathing. Conclusions Inhalation of H2S at either 27° or 35°C reversibly depresses cardiovascular function without changing blood pressure in mice. Breathing H2S also induces a rapidly reversible reduction of metabolic rate at either body temperature. PMID:18362598

Rare-earth metal halogenide encapsulation-induced modifications in Raman spectra of single-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Kharlamova, M. V.

2015-01-01

In the present work, a detailed Raman spectroscopy investigation on the single-walled carbon nanotubes (SWCNTs) filled with praseodymium chloride, terbium chloride and thulium chloride was performed. The salts were incorporated inside the SWCNTs by a capillary filling method using melts, and the high-resolution transmission electron microscopy data proved the high filling degree of the nanotube channels. A thorough analysis of the radial breathing mode and G-band of the Raman spectra of the pristine and filled SWCNTs showed that the encapsulated salts cause acceptor doping of the host nanotubes, and the doping efficiency depends on the compound. The incorporated thulium chloride has the strongest doping effect on the SWCNTs, whereas praseodymium chloride has the weakest effect. It was found that the encapsulated salts modify more significantly the electronic structure of metallic nanotubes than semiconducting SWCNTs.

Microsoft Kinect Visual and Depth Sensors for Breathing and Heart Rate Analysis

PubMed Central

Procházka, Aleš; Schätz, Martin; Vyšata, Oldřich; Vališ, Martin

2016-01-01

This paper is devoted to a new method of using Microsoft (MS) Kinect sensors for non-contact monitoring of breathing and heart rate estimation to detect possible medical and neurological disorders. Video sequences of facial features and thorax movements are recorded by MS Kinect image, depth and infrared sensors to enable their time analysis in selected regions of interest. The proposed methodology includes the use of computational methods and functional transforms for data selection, as well as their denoising, spectral analysis and visualization, in order to determine specific biomedical features. The results that were obtained verify the correspondence between the evaluation of the breathing frequency that was obtained from the image and infrared data of the mouth area and from the thorax movement that was recorded by the depth sensor. Spectral analysis of the time evolution of the mouth area video frames was also used for heart rate estimation. Results estimated from the image and infrared data of the mouth area were compared with those obtained by contact measurements by Garmin sensors (www.garmin.com). The study proves that simple image and depth sensors can be used to efficiently record biomedical multidimensional data with sufficient accuracy to detect selected biomedical features using specific methods of computational intelligence. The achieved accuracy for non-contact detection of breathing rate was 0.26% and the accuracy of heart rate estimation was 1.47% for the infrared sensor. The following results show how video frames with depth data can be used to differentiate different kinds of breathing. The proposed method enables us to obtain and analyse data for diagnostic purposes in the home environment or during physical activities, enabling efficient human–machine interaction. PMID:27367687

Microsoft Kinect Visual and Depth Sensors for Breathing and Heart Rate Analysis.

PubMed

Procházka, Aleš; Schätz, Martin; Vyšata, Oldřich; Vališ, Martin

2016-06-28

This paper is devoted to a new method of using Microsoft (MS) Kinect sensors for non-contact monitoring of breathing and heart rate estimation to detect possible medical and neurological disorders. Video sequences of facial features and thorax movements are recorded by MS Kinect image, depth and infrared sensors to enable their time analysis in selected regions of interest. The proposed methodology includes the use of computational methods and functional transforms for data selection, as well as their denoising, spectral analysis and visualization, in order to determine specific biomedical features. The results that were obtained verify the correspondence between the evaluation of the breathing frequency that was obtained from the image and infrared data of the mouth area and from the thorax movement that was recorded by the depth sensor. Spectral analysis of the time evolution of the mouth area video frames was also used for heart rate estimation. Results estimated from the image and infrared data of the mouth area were compared with those obtained by contact measurements by Garmin sensors (www.garmin.com). The study proves that simple image and depth sensors can be used to efficiently record biomedical multidimensional data with sufficient accuracy to detect selected biomedical features using specific methods of computational intelligence. The achieved accuracy for non-contact detection of breathing rate was 0.26% and the accuracy of heart rate estimation was 1.47% for the infrared sensor. The following results show how video frames with depth data can be used to differentiate different kinds of breathing. The proposed method enables us to obtain and analyse data for diagnostic purposes in the home environment or during physical activities, enabling efficient human-machine interaction.

Small Airway Dysfunction and Abnormal Exercise Responses

PubMed Central

Petsonk, Edward L.; Stansbury, Robert C.; Beeckman-Wagner, Lu-Ann; Long, Joshua L.; Wang, Mei Lin

2016-01-01

Rationale Coal mine dust exposure can cause symptoms and loss of lung function from multiple mechanisms, but the roles of each disease process are not fully understood. Objectives We investigated the implications of small airway dysfunction for exercise physiology among a group of workers exposed to coal mine dust. Methods Twenty coal miners performed spirometry, first breathing air and then helium-oxygen, single-breath diffusing capacity, and computerized chest tomography, and then completed cardiopulmonary exercise testing. Measurements and Main Results Six participants meeting criteria for small airway dysfunction were compared with 14 coal miners who did not. At submaximal workload, miners with small airway dysfunction used a higher proportion of their maximum voluntary ventilation and had higher ventilatory equivalents for both O2 and CO2. Regression modeling indicated that inefficient ventilation was significantly related to small airway dysfunction but not to FEV1 or diffusing capacity. At the end of exercise, miners with small airway dysfunction had 27% lower O2 consumption. Conclusions Small airway abnormalities may be associated with important inefficiency of exercise ventilation. In dust-exposed individuals with only mild abnormalities on resting lung function tests or chest radiographs, cardiopulmonary exercise testing may be important in defining causes of exercise intolerance. PMID:27073987

Low-power system for the acquisition of the respiratory signal of neonates using diaphragmatic electromyography.

PubMed

Torres, Róbinson; López-Isaza, Sergio; Mejía-Mejía, Elisa; Paniagua, Viviana; González, Víctor

2017-01-01

An apnea episode is defined as the cessation of breathing for ≥15 seconds or as any suspension of breathing accompanied by hypoxia and bradycardia. Obtaining information about the respiratory system in a neonate can be accomplished using electromyography signals from the diaphragm muscle. The purpose of this paper is to illustrate a method by which the respiratory and electrocardiographic signals from neonates can be obtained using diaphragmatic electromyography. The system was developed using single-supply, micropower components, which deliver a low-power consumption system appropriate for the development of portable devices. The stages of the system were tested in both adult and neonate patients. The system delivers signals as those expected in both patients and allows the acquisition of respiratory signals directly from the diaphragmatic electromyography. This low-power system may present a good alternative for monitoring the cardiac and respiratory activity in newborn babies, both in the hospital and at home. The system delivers good signals but needs to be validated for its use in neonates. It is being used in the Neonatal Intensive Care Unit of the Hospital General de Medellín Luz Castro de Gutiérrez.

Dynamic volume vs respiratory correlated 4DCT for motion assessment in radiation therapy simulation.

PubMed

Coolens, Catherine; Bracken, John; Driscoll, Brandon; Hope, Andrew; Jaffray, David

2012-05-01

Conventional (i.e., respiratory-correlated) 4DCT exploits the repetitive nature of breathing to provide an estimate of motion; however, it has limitations due to binning artifacts and irregular breathing in actual patient breathing patterns. The aim of this work was to evaluate the accuracy and image quality of a dynamic volume, CT approach (4D(vol)) using a 320-slice CT scanner to minimize these limitations, wherein entire image volumes are acquired dynamically without couch movement. This will be compared to the conventional respiratory-correlated 4DCT approach (RCCT). 4D(vol) CT was performed and characterized on an in-house, programmable respiratory motion phantom containing multiple geometric and morphological "tumor" objects over a range of regular and irregular patient breathing traces obtained from 3D fluoroscopy and compared to RCCT. The accuracy of volumetric capture and breathing displacement were evaluated and compared with the ground truth values and with the results reported using RCCT. A motion model was investigated to validate the number of motion samples needed to obtain accurate motion probability density functions (PDF). The impact of 4D image quality on this accuracy was then investigated. Dose measurements using volumetric and conventional scan techniques were also performed and compared. Both conventional and dynamic volume 4DCT methods were capable of estimating the programmed displacement of sinusoidal motion, but patient breathing is known to not be regular, and obvious differences were seen for realistic, irregular motion. The mean RCCT amplitude error averaged at 4 mm (max. 7.8 mm) whereas the 4D(vol) CT error stayed below 0.5 mm. Similarly, the average absolute volume error was lower with 4D(vol) CT. Under irregular breathing, the 4D(vol) CT method provides a close description of the motion PDF (cross-correlation 0.99) and is able to track each object, whereas the RCCT method results in a significantly different PDF from the ground truth, especially for smaller tumors (cross-correlation ranging between 0.04 and 0.69). For the protocols studied, the dose measurements were higher in the 4D(vol) CT method (40%), but it was shown that significant mAs reductions can be achieved by a factor of 4-5 while maintaining image quality and accuracy. 4D(vol) CT using a scanner with a large cone-angle is a promising alternative for improving the accuracy with which respiration-induced motion can be characterized, particularly for patients with irregular breathing motion. This approach also generates 4DCT image data with a reduced total scan time compared to a RCCT scan, without the need for image binning or external respiration signals within the 16 cm scan length. Scan dose can be made comparable to RCCT by optimization of the scan parameters. In addition, it provides the possibility of measuring breathing motion for more than one breathing cycle to assess stability and obtain a more accurate motion PDF, which is currently not feasible with the conventional RCCT approach.

Estimating lifetime risk from spot biomarker data and intra‐class correlation coefficients (ICC)

EPA Science Inventory

Human biomarker measurements in tissues including blood, breath, and urine can serve as efficient surrogates for environmental monitoring because a single biological sample integrates personal exposure across all environmental media and uptake pathways. However, biomarkers repres...

Nonuniformity of diffusing capacity from small alveolar gas samples is increased in smokers.

PubMed

Cotton, D J; Mink, J T; Graham, B L

1998-01-01

Although centrilobular emphysema, and small airway, interstitial and alveoli inflammation can be detected pathologically in the lungs of smokers with relatively well preserved lung function, these changes are difficult to assess using available physiological tests. Because submaximal single breath washout (SBWSM) manoeuvres improve the detection of abnormalities in ventilation inhomogeneity in the lung periphery in smokers compared with traditional vital capacity manoeuvres, SBWSM manoeuvres were used in this study to measure temporal differences in diffusing capacity using a rapid response carbon monoxide analyzer. To determine whether abnormalities in the lung periphery can be detected in smokers with normal forced expired volumes in 1 s using the three-equation diffusing capacity (DLcoSB-3EQ) among small alveolar gas samples and whether the abnormalities correlate with increases in peripheral ventilation inhomogeneity. Cross-sectional study in 21 smokers and 21 nonsmokers all with normal forced exhaled flow rates. Both smokers and nonsmokers performed SBWSM manoeuvres consisting of slow inhalation of test gas from functional residual capacity to one-half inspiratory capacity with either 0 or 10 s of breath holding and slow exhalation to residual volume (RV). They also performed conventional vital capacity single breath (SBWVC) manoeuvres consisting of slow inhalation of test gas from RV to total lung capacity and, without breath holding, slow exhalation to RV. DLcoSB-3EQ was calculated from the total alveolar gas sample. DLcoSB-3EQ was also calculated from four equal sequential, simulated aliquots of the total alveolar gas sample. DLcoSB-3EQ values from the four alveolar samples were normalized by expressing each as a percentge of DLcoSB-3EQ from the entire alveolar gas sample. An index of variation (DI) among the small-sample DLcoSB-3EQ values was correlated with the normalized phase III helium slope (Sn) and the mixing efficiency (Emix). For SBWSM, DI was increased in smokers at 0 s of breath holding compared with nonsmokers, and correlated with age, smoking pack-years and Sn. The decrease in DI with breath holding was greater in smokers and correlated with the change in Sn with breath holding. For SBWVC manoeuvres, there were no differences due to smoking in Sn or Emix, but DI was increased in smokers and correlated with age and smoking pack-years, but not with Sn. For SBWSM manoeuvres the increase in DI in smokers correlated with breath hold time-dependent increases in Sn, suggesting that the changes in DI reflected the same structural alterations that caused increases in peripheral ventilation inhomogeneity. For SBWVC manoeuvres, the increase in DI in smokers was not associated with changes in ventilation inhomogeneity, suggesting that the effect of smoking on DI during this manoeuvre was due to smoke-related changes in alveolar capillary diffusion, rather than due solely to alterations in the distribution of ventilation.

Changes in the palatal dimensions of mouth breathing children caused by nasal obstruction

NASA Astrophysics Data System (ADS)

Indiarti, I. S.; Setyanto, D. B.; Kusumaningrum, A.; Budiardjo, S. B.

2017-08-01

During children’s growth and development, the breathing process plays an important role in craniofacial growth, especially of the palate. Nose breathing can stimulate the lateral growth of the maxilla, thus making the palate flat. Disturbances in nose breathing caused by nasal obstruction such as allergic rhinitis, adenoid hypertrophy, rhinosinusitis, nasal polyps, and obstructive sleep apnea can lead to a mouth breathing habit in children. This habit can cause palatal dimension changes such as a narrow V-shaped maxillary arch and a high palatal vault. This study analyzed the relationship between the mouth breathing habit in children who have nasal obstruction and palatal dimension changes. A cross-sectional descriptive study was conducted with a consecutive sampling method on children 7-18 years old with a history of allergic rhinitis, adenoid hypertrophy, rhinosinusitis, nasal polyps, and obstructive sleep apnea in the Pediatric Respirology and Pediatric Immunology Allergy Outpatient Clinic Kiara Maternal and Child Health Center at Cipto Mangunkusumo Hospital in Jakarta. The palatal dimensions were measured by the height and transversal width of the hard palate of castings of each child’s upper dental arch using vernier calipers. Palatal dimension changes were found in children with a mouth breathing habit due to nasal obstruction.

Volatile Biomarkers in Breath Associated With Liver Cirrhosis — Comparisons of Pre- and Post-liver Transplant Breath Samples

PubMed Central

Fernández del Río, R.; O'Hara, M.E.; Holt, A.; Pemberton, P.; Shah, T.; Whitehouse, T.; Mayhew, C.A.

2015-01-01

Background The burden of liver disease in the UK has risen dramatically and there is a need for improved diagnostics. Aims To determine which breath volatiles are associated with the cirrhotic liver and hence diagnostically useful. Methods A two-stage biomarker discovery procedure was used. Alveolar breath samples of 31 patients with cirrhosis and 30 healthy controls were mass spectrometrically analysed and compared (stage 1). 12 of these patients had their breath analysed after liver transplant (stage 2). Five patients were followed longitudinally as in-patients in the post-transplant period. Results Seven volatiles were elevated in the breath of patients versus controls. Of these, five showed statistically significant decrease post-transplant: limonene, methanol, 2-pentanone, 2-butanone and carbon disulfide. On an individual basis limonene has the best diagnostic capability (the area under a receiver operating characteristic curve (AUROC) is 0.91), but this is improved by combining methanol, 2-pentanone and limonene (AUROC curve 0.95). Following transplant, limonene shows wash-out characteristics. Conclusions Limonene, methanol and 2-pentanone are breath markers for a cirrhotic liver. This study raises the potential to investigate these volatiles as markers for early-stage liver disease. By monitoring the wash-out of limonene following transplant, graft liver function can be non-invasively assessed. PMID:26501124

Usefulness of Guided Breathing for Dose Rate-Regulated Tracking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han-Oh, Sarah; Department of Radiation Oncology, University of Maryland Medical System, Baltimore, MD; Yi, Byong Yong

2009-02-01

Purpose: To evaluate the usefulness of guided breathing for dose rate-regulated tracking (DRRT), a new technique to compensate for intrafraction tumor motion. Methods and Materials: DRRT uses a preprogrammed multileaf collimator sequence that tracks the tumor motion derived from four-dimensional computed tomography and the corresponding breathing signals measured before treatment. Because the multileaf collimator speed can be controlled by adjusting the dose rate, the multileaf collimator positions are adjusted in real time during treatment by dose rate regulation, thereby maintaining synchrony with the tumor motion. DRRT treatment was simulated with free, audio-guided, and audiovisual-guided breathing signals acquired from 23 lungmore » cancer patients. The tracking error and duty cycle for each patient were determined as a function of the system time delay (range, 0-1.0 s). Results: The tracking error and duty cycle averaged for all 23 patients was 1.9 {+-} 0.8 mm and 92% {+-} 5%, 1.9 {+-} 1.0 mm and 93% {+-} 6%, and 1.8 {+-} 0.7 mm and 92% {+-} 6% for the free, audio-guided, and audiovisual-guided breathing, respectively, for a time delay of 0.35 s. The small differences in both the tracking error and the duty cycle with guided breathing were not statistically significant. Conclusion: DRRT by its nature adapts well to variations in breathing frequency, which is also the motivation for guided-breathing techniques. Because of this redundancy, guided breathing does not result in significant improvements for either the tracking error or the duty cycle when DRRT is used for real-time tumor tracking.« less

Δ(9)-Tetrahydrocannabinol concentrations in exhaled breath and physiological effects following cannabis intake - A pilot study using illicit cannabis.

PubMed

Coucke, Line; Massarini, Enrico; Ostijn, Zachery; Beck, Olof; Verstraete, Alain G

2016-09-01

Δ(9)-Tetrahydrocannabinol (THC) can be measured in exhaled breath by using an aerosol particle collection device. The sampling procedure is simple, non-invasive and takes only 2-3min. In the present study we measured the amount of THC in exhaled breath of cannabis users at specific time intervals up to 3h after smoking one cannabis cigarette. The breath concentration-effect relationship was studied by measuring the pulse rate and the pupil diameter to assess physiological changes. THC and the main metabolite 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol were analyzed in exhaled breath by a liquid chromatography-tandem mass spectrometry method. Thirteen subjects (9 males and 4 females, aged 23-24years) participated. Five of those were using cannabis more frequently than monthly. THC was detected in most subjects already at baseline, concentrations increased following smoking and remained detectable for over 3h (mean THC concentration in breath at 3h: 1479pg/sample). Pulse rate (p=0.015) and pupil diameter (p=0.044) were significantly altered up to 30min after smoking. The detection window of cannabis in breath after smoking one cannabis cigarette in occasional and chronic smokers was at least 3h. Only THC was detected, and not the metabolite. The THC concentration in exhaled breath was related to the physiological changes that occur over time. Exhaled breath can be used to detect recent cannabis exposure. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Variations in respiratory excretion of carbon dioxide can be used to calculate pulmonary blood flow.

PubMed

Preiss, David A; Azami, Takafumi; Urman, Richard D

2015-02-01

A non-invasive means of measuring pulmonary blood flow (PBF) would have numerous benefits in medicine. Traditionally, respiratory-based methods require breathing maneuvers, partial rebreathing, or foreign gas mixing because exhaled CO2 volume on a per-breath basis does not accurately represent alveolar exchange of CO2. We hypothesized that if the dilutional effect of the functional residual capacity was accounted for, the relationship between the calculated volume of CO2 removed per breath and the alveolar partial pressure of CO2 would be reversely linear. A computer model was developed that uses variable tidal breathing to calculate CO2 removal per breath at the level of the alveoli. We iterated estimates for functional residual capacity to create the best linear fit of alveolar CO2 pressure and CO2 elimination for 10 minutes of breathing and incorporated the volume of CO2 elimination into the Fick equation to calculate PBF. The relationship between alveolar pressure of CO2 and CO2 elimination produced an R(2) = 0.83. The optimal functional residual capacity differed from the "actual" capacity by 0.25 L (8.3%). The repeatability coefficient leveled at 0.09 at 10 breaths and the difference between the PBF calculated by the model and the preset blood flow was 0.62 ± 0.53 L/minute. With variations in tidal breathing, a linear relationship exists between alveolar CO2 pressure and CO2 elimination. Existing technology may be used to calculate CO2 elimination during quiet breathing and might therefore be used to accurately calculate PBF in humans with healthy lungs.

(13)C-Breath testing in animals: theory, applications, and future directions.

PubMed

McCue, Marshall D; Welch, Kenneth C

2016-04-01

The carbon isotope values in the exhaled breath of an animal mirror the carbon isotope values of the metabolic fuels being oxidized. The measurement of stable carbon isotopes in carbon dioxide is called (13)C-breath testing and offers a minimally invasive method to study substrate oxidation in vivo. (13)C-breath testing has been broadly used to study human exercise, nutrition, and pathologies since the 1970s. Owing to reduced use of radioactive isotopes and the increased convenience and affordability of (13)C-analyzers, the past decade has witnessed a sharp increase in the use of breath testing throughout comparative physiology--especially to answer questions about how and when animals oxidize particular nutrients. Here, we review the practical aspects of (13)C-breath testing and identify the strengths and weaknesses of different methodological approaches including the use of natural abundance versus artificially-enriched (13)C tracers. We critically compare the information that can be obtained using different experimental protocols such as diet-switching versus fuel-switching. We also discuss several factors that should be considered when designing breath testing experiments including extrinsic versus intrinsic (13)C-labelling and different approaches to model nutrient oxidation. We use case studies to highlight the myriad applications of (13)C-breath testing in basic and clinical human studies as well as comparative studies of fuel use, energetics, and carbon turnover in multiple vertebrate and invertebrate groups. Lastly, we call for increased and rigorous use of (13)C-breath testing to explore a variety of new research areas and potentially answer long standing questions related to thermobiology, locomotion, and nutrition.

Real-time tracking of respiratory-induced tumor motion by dose-rate regulation

NASA Astrophysics Data System (ADS)

Han-Oh, Yeonju Sarah

We have developed a novel real-time tumor-tracking technology, called Dose-Rate-Regulated Tracking (DRRT), to compensate for tumor motion caused by breathing. Unlike other previously proposed tumor-tracking methods, this new method uses a preprogrammed dynamic multileaf collimator (MLC) sequence in combination with real-time dose-rate control. This new scheme circumvents the technical challenge in MLC-based tumor tracking, that is to control the MLC motion in real time, based on real-time detected tumor motion. The preprogrammed MLC sequence describes the movement of the tumor, as a function of breathing phase, amplitude, or tidal volume. The irregularity of tumor motion during treatment is handled by real-time regulation of the dose rate, which effectively speeds up or slows down the delivery of radiation as needed. This method is based on the fact that all of the parameters in dynamic radiation delivery, including MLC motion, are enslaved to the cumulative dose, which, in turn, can be accelerated or decelerated by varying the dose rate. Because commercially available MLC systems do not allow the MLC delivery sequence to be modified in real time based on the patient's breathing signal, previously proposed tumor-tracking techniques using a MLC cannot be readily implemented in the clinic today. By using a preprogrammed MLC sequence to handle the required motion, the task for real-time control is greatly simplified. We have developed and tested the pre- programmed MLC sequence and the dose-rate regulation algorithm using lung-cancer patients breathing signals. It has been shown that DRRT can track the tumor with an accuracy of less than 2 mm for a latency of the DRRT system of less than 0.35 s. We also have evaluated the usefulness of guided breathing for DRRT. Since DRRT by its very nature can compensate for breathing-period changes, guided breathing was shown to be unnecessary for real-time tracking when using DRRT. Finally, DRRT uses the existing dose-rate control system that is provided for current linear accelerators. Therefore, DRRT can be achieved with minimal modification of existing technology, and this can shorten substantially the time necessary to establish DRRT in clinical practice.

Evaluation of model-based methods in estimating respiratory mechanics in the presence of variable patient effort.

PubMed

Redmond, Daniel P; Chiew, Yeong Shiong; Major, Vincent; Chase, J Geoffrey

2016-09-23

Monitoring of respiratory mechanics is required for guiding patient-specific mechanical ventilation settings in critical care. Many models of respiratory mechanics perform poorly in the presence of variable patient effort. Typical modelling approaches either attempt to mitigate the effect of the patient effort on the airway pressure waveforms, or attempt to capture the size and shape of the patient effort. This work analyses a range of methods to identify respiratory mechanics in volume controlled ventilation modes when there is patient effort. The models are compared using 4 Datasets, each with a sample of 30 breaths before, and 2-3 minutes after sedation has been administered. The sedation will reduce patient efforts, but the underlying pulmonary mechanical properties are unlikely to change during this short time. Model identified parameters from breathing cycles with patient effort are compared to breathing cycles that do not have patient effort. All models have advantages and disadvantages, so model selection may be specific to the respiratory mechanics application. However, in general, the combined method of iterative interpolative pressure reconstruction, and stacking multiple consecutive breaths together has the best performance over the Dataset. The variability of identified elastance when there is patient effort is the lowest with this method, and there is little systematic offset in identified mechanics when sedation is administered. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Electrospun polystyrene/graphene nanofiber film as a novel adsorbent of thin film microextraction for extraction of aldehydes in human exhaled breath condensates.

PubMed

Huang, Jing; Deng, Hongtao; Song, Dandan; Xu, Hui

2015-06-09

In the current study, we introduced a novel polystyrene/graphene (PS/G) composite nanofiber film for thin film microextraction (TFME) for the first time. The PS/G nanofiber film was fabricated on the surface of filter paper by a facile electrospinning method. The morphology and extraction performance of the resultant composite film were investigated systematically. The PS/G nanofiber film exhibited porous fibrous structure, large surface area and strong hydrophobicity. A new thin film microextraction-high performance liquid chromatography (TFME-HPLC) method was developed for the determination of six aldehydes in human exhaled breath condensates. The method showed high enrichment efficiency and fast analysis speed. Under the optimal conditions, the linear ranges of the analytes were in the range of 0.02-30 μmol L(-1) with correlation coefficients above 0.9938, and the recoveries were between 79.8% and 105.6% with the relative standard deviation values lower than 16.3% (n=5). The limits of quantification of six aldehydes ranged from 13.8 to 64.6 nmol L(-1). The established method was successfully applied for the quantification of aldehyde metabolites in exhaled breath condensates of lung cancer patients and healthy people. Taken together, the TFME-HPLC method provides a simple, rapid, sensitive, cost-effective, non-invasion approach for the analysis of linear aliphatic aldehydes in human exhaled breath condensates. Copyright © 2015 Elsevier B.V. All rights reserved.

Atropine microdialysis within or near the pre-Botzinger Complex increases breathing frequency more during wakefulness than during NREM sleep.

PubMed

Muere, Clarissa; Neumueller, Suzanne; Miller, Justin; Olesiak, Samantha; Hodges, Matthew R; Pan, Lawrence; Forster, Hubert V

2013-03-01

Normal activity of neurons within the medullary ventral respiratory column (VRC) in or near the pre-Bötzinger Complex (preBötC) is dependent on the balance of inhibitory and excitatory neuromodulators acting at their respective receptors. The role of cholinergic neuromodulation during awake and sleep states is unknown. Accordingly, our objective herein was to test the hypotheses that attenuation of cholinergic modulation of VRC/preBötC neurons in vivo with atropine would: 1) decrease breathing frequency more while awake than during non-rapid-eye-movement (NREM) sleep and 2) increase other excitatory neuromodulators. To test these hypotheses, we unilaterally dialyzed mock cerebrospinal fluid (mCSF) or 50 mM atropine in mCSF in or near the preBötC region of adult goats during the awake (n = 9) and NREM sleep (n = 7) states. Breathing was monitored, and effluent dialysate was collected for analysis of multiple neurochemicals. Compared with dialysis of mCSF alone, atropine increased (P < 0.05) breathing frequency while awake during the day [+10 breaths (br)/min] and at night (+9 br/min) and, to a lesser extent, during NREM sleep (+5 br/min). Atropine increased (P < 0.05) effluent concentrations of serotonin (5-HT), substance P (SP), and glycine during the day and at night. When atropine was dialyzed in one preBötC and mCSF in the contralateral preBötC, 5-HT and SP increased only at the site of atropine dialysis. We conclude: 1) attenuation of a single neuromodulator results in local changes in other neuromodulators that affect ventilatory control, 2) effects of perturbations of cholinergic neuromodulation on breathing are state-dependent, and 3) interpretation of perturbations in vivo requires consideration of direct and indirect effects.

Association between in vivo alcohol metabolism and genetic variation in pathways that metabolize the carbon skeleton of ethanol and NADH reoxidation in the Alcohol Challenge Twin Study

PubMed Central

Lind, Penelope A; Macgregor, Stuart; Heath, Andrew C; Madden, Pamela AF; Montgomery, Grant W; Martin, Nicholas G; Whitfield, John B

2013-01-01

Background Variation in alcohol metabolism affects the duration of intoxication and alcohol use. While the majority of genetic association studies investigating variation in alcohol metabolism have focused on polymorphisms in alcohol or aldehyde dehydrogenases, we have now tested for association with genes in alternative metabolic pathways that catalyze the carbon skeleton of ethanol and NADH reoxidation. Methods 950 single nucleotide polymorphisms (SNPs) spanning 14 genes (ACN9, ACSS1, ACSS2, ALDH1A1, CAT, CYP2E1, GOT1, GOT2, MDH1, MDH2, SLC25A10, SLC25A11, SLC25A12, SLC25A13) were genotyped in 352 young adults who participated in an alcohol challenge study. Traits tested were blood and breath alcohol concentration, peak alcohol concentration and rates of alcohol absorption and elimination. Allelic association was tested using quantitative univariate and multivariate methods. Results A CYP2E1 promoter SNP (rs4838767, minor allele frequency 0.008) exceeded the threshold for study-wide significance (4.01 × 10−5) for two early blood alcohol concentration (BAC), eight breath alcohol concentration (BrAC) measures and the peak BrAC. For each phenotype the minor C-allele was related to a lower alcohol concentration, most strongly for the fourth BrAC (P = 2.07 × 10−7) explaining ~8% of the phenotypic variance. We also observed suggestive patterns of association with variants in ALDH1A1 and on chromosome 17 near SLC25A11 for aspects of blood and breath alcohol metabolism. A SNP upstream of GOT1 (rs2490286) reached study-wide significance for multivariate BAC metabolism (P = 0.000040). Conclusions Overall, we did not find strong evidence that variation in genes coding for proteins that further metabolize the carbon backbone of acetaldehyde, or contribute to mechanisms for regenerating NAD from NADH, affects alcohol metabolism in our European-descent subjects. However, based on the breath alcohol data, variation in the promoter of CYP2E1 may play a role in pre-absorptive or early hepatic alcohol metabolism, but more samples are required to validate this finding. PMID:22577853

SU-E-J-185: A Systematic Review of Breathing Guidance in Radiation Oncology and Radiology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pollock, S; Keall, P; Keall, R

Purpose: The advent of image-guided radiation therapy (IGRT) has led to dramatic improvements in the accuracy of treatment delivery in radiotherapy. Such advancements have highlighted the deleterious impact tumor motion can have on both image quality and radiation treatment delivery. One approach to reducing tumor motion is the use of breathing guidance systems during imaging and treatment. A review of such research had not yet been performed, it was therefore our aim to perform a systematic review of breathing guidance interventions within the fields of radiation oncology and radiology. Methods: Results of online database searches were filtered in accordance tomore » a set of eligibility criteria. The search, filtration, and analysis of articles were conducted in accordance with the PRISMAStatement reporting standard (Preferred Reporting Items for Systematic reviews and Meta-Analyses) utilizing the PICOS approach (Participants, Intervention, Comparison, Outcome, Study design). Participants: Cancer patients, healthy volunteers. Intervention: Biofeedback breathing guidance systems. Comparison: No breathing guidance of the same breathing type. Outcome: Regularity of breathing signal and anatomic/tumor motion, medical image quality, radiation treatment margins and coverage, medical imaging and radiation treatment times. Study design: Quantitative and controlled prospective or retrospective trials. Results: The systematic search yielded a total of 479 articles, which were filtered down to 27 relevant articles in accordance to the eligibility criteria. The vast majority of investigated outcomes were significantly positively impacted by the use of breathing guidance; however, this was dependent upon the nature of the breathing guidance system and study design. In 25/27 studies significant improvements from the use of breathing guidance were observed. Conclusion: The results found here indicate that further clinical studies are warranted which quantify more comprehensively the clinical impact of The results found here indicate that further clinical studies are warranted which quantify more comprehensively the clinical impact of breathing guidance interventions.« less

Reliable quantification of BOLD fMRI cerebrovascular reactivity despite poor breath-hold performance.

PubMed

Bright, Molly G; Murphy, Kevin

2013-12-01

Cerebrovascular reactivity (CVR) can be mapped using BOLD fMRI to provide a clinical insight into vascular health that can be used to diagnose cerebrovascular disease. Breath-holds are a readily accessible method for producing the required arterial CO2 increases but their implementation into clinical studies is limited by concerns that patients will demonstrate highly variable performance of breath-hold challenges. This study assesses the repeatability of CVR measurements despite poor task performance, to determine if and how robust results could be achieved with breath-holds in patients. Twelve healthy volunteers were scanned at 3 T. Six functional scans were acquired, each consisting of 6 breath-hold challenges (10, 15, or 20 s duration) interleaved with periods of paced breathing. These scans simulated the varying breath-hold consistency and ability levels that may occur in patient data. Uniform ramps, time-scaled ramps, and end-tidal CO2 data were used as regressors in a general linear model in order to measure CVR at the grey matter, regional, and voxelwise level. The intraclass correlation coefficient (ICC) quantified the repeatability of the CVR measurement for each breath-hold regressor type and scale of interest across the variable task performances. The ramp regressors did not fully account for variability in breath-hold performance and did not achieve acceptable repeatability (ICC<0.4) in several regions analysed. In contrast, the end-tidal CO2 regressors resulted in "excellent" repeatability (ICC=0.82) in the average grey matter data, and resulted in acceptable repeatability in all smaller regions tested (ICC>0.4). Further analysis of intra-subject CVR variability across the brain (ICCspatial and voxelwise correlation) supported the use of end-tidal CO2 data to extract robust whole-brain CVR maps, despite variability in breath-hold performance. We conclude that the incorporation of end-tidal CO2 monitoring into scanning enables robust, repeatable measurement of CVR that makes breath-hold challenges suitable for routine clinical practice. © 2013.

eAMI: A Qualitative Quantification of Periodic Breathing Based on Amplitude of Oscillations

PubMed Central

Fernandez Tellez, Helio; Pattyn, Nathalie; Mairesse, Olivier; Dolenc-Groselj, Leja; Eiken, Ola; Mekjavic, Igor B.; Migeotte, P. F.; Macdonald-Nethercott, Eoin; Meeusen, Romain; Neyt, Xavier

2015-01-01

Study Objectives: Periodic breathing is sleep disordered breathing characterized by instability in the respiratory pattern that exhibits an oscillatory behavior. Periodic breathing is associated with increased mortality, and it is observed in a variety of situations, such as acute hypoxia, chronic heart failure, and damage to respiratory centers. The standard quantification for the diagnosis of sleep related breathing disorders is the apnea-hypopnea index (AHI), which measures the proportion of apneic/hypopneic events during polysomnography. Determining the AHI is labor-intensive and requires the simultaneous recording of airflow and oxygen saturation. In this paper, we propose an automated, simple, and novel methodology for the detection and qualification of periodic breathing: the estimated amplitude modulation index (eAMI). Patients or Participants: Antarctic cohort (3,800 meters): 13 normal individuals. Clinical cohort: 39 different patients suffering from diverse sleep-related pathologies. Measurements and Results: When tested in a population with high levels of periodic breathing (Antarctic cohort), eAMI was closely correlated with AHI (r = 0.95, P < 0.001). When tested in the clinical setting, the proposed method was able to detect portions of the signal in which subclinical periodic breathing was validated by an expert (n = 93; accuracy = 0.85). Average eAMI was also correlated with the loop gain for the combined clinical and Antarctica cohorts (r = 0.58, P < 0.001). Conclusions: In terms of quantification and temporal resolution, the eAMI is able to estimate the strength of periodic breathing and the underlying loop gain at any given time within a record. The impaired prognosis associated with periodic breathing makes its automated detection and early diagnosis of clinical relevance. Citation: Fernandez Tellez H, Pattyn N, Mairesse O, Dolenc-Groselj L, Eiken O, Mekjavic IB, Migeotte PF, Macdonald-Nethercott E, Meeusen R, Neyt X. eAMI: a qualitative quantification of periodic breathing based on amplitude of oscillations. SLEEP 2015;38(3):381–389. PMID:25581914

Investigation of Exhaled Breath Samples from Patients with Alzheimer's Disease Using Gas Chromatography-Mass Spectrometry and an Exhaled Breath Sensor System.

PubMed

Lau, Hui-Chong; Yu, Joon-Boo; Lee, Ho-Won; Huh, Jeung-Soo; Lim, Jeong-Ok

2017-08-03

Exhaled breath is a body secretion, and the sampling process of this is simple and cost effective. It can be non-invasively collected for diagnostic procedures. Variations in the chemical composition of exhaled breath resulting from gaseous exchange in the extensive capillary network of the body are proposed to be associated with pathophysiological changes. In light of the foreseeable potential of exhaled breath as a diagnostic specimen, we used gas chromatography and mass spectrometry (GC-MS) to study the chemical compounds present in exhaled breath samples from patients with Alzheimer's disease (AD), Parkinson's disease (PD), and from healthy individuals as a control group. In addition, we also designed and developed a chemical-based exhaled breath sensor system to examine the distribution pattern in the patient and control groups. The results of our study showed that several chemical compounds, such as 1-phenantherol and ethyl 3-cyano-2,3-bis (2,5,-dimethyl-3-thienyl)-acrylate, had a higher percentage area in the AD group than in the PD and control groups. These results may indicate an association of these chemical components in exhaled breath with the progression of disease. In addition, in-house fabricated exhaled breath sensor systems, containing several types of gas sensors, showed significant differences in terms of the normalized response of the sensitivity characteristics between the patient and control groups. A subsequent clustering analysis was able to distinguish between the AD patients, PD patients, and healthy individuals using principal component analysis, Sammon's mapping, and a combination of both methods, in particular when using the exhaled breath sensor array system A consisting of eight sensors. With this in mind, the exhaled breath sensor system could provide alternative option for diagnosis and be applied as a useful, effective tool for the screening and diagnosis of AD in the near future.

Comparative analysis between the alveolar recruitment maneuver and breath stacking technique in patients with acute lung injury

PubMed Central

Porto, Elias Ferreira; Tavolaro, Kelly Cristiani; Kumpel, Claudia; Oliveira, Fernanda Augusta; Sousa, Juciaria Ferreira; de Carvalho, Graciele Vieira; de Castro, Antonio Adolfo Mattos

2014-01-01

Objective To compare the effectiveness of the alveolar recruitment maneuver and the breath stacking technique with respect to lung mechanics and gas exchange in patients with acute lung injury. Methods Thirty patients were distributed into two groups: Group 1 - breath stacking; and Group 2 - alveolar recruitment maneuver. After undergoing conventional physical therapy, all patients received both treatments with an interval of 1 day between them. In the first group, the breath stacking technique was used initially, and subsequently, the alveolar recruitment maneuver was applied. Group 2 patients were initially subjected to alveolar recruitment, followed by the breath stacking technique. Measurements of lung compliance and airway resistance were evaluated before and after the use of both techniques. Gas analyses were collected before and after the techniques were used to evaluate oxygenation and gas exchange. Results Both groups had a significant increase in static compliance after breath stacking (p=0.021) and alveolar recruitment (p=0.03), but with no significant differences between the groups (p=0.95). The dynamic compliance did not increase for the breath stacking (p=0.22) and alveolar recruitment (p=0.074) groups, with no significant difference between the groups (p=0.11). The airway resistance did not decrease for either groups, i.e., breath stacking (p=0.91) and alveolar recruitment (p=0.82), with no significant difference between the groups (p=0.39). The partial pressure of oxygen increased significantly after breath stacking (p=0.013) and alveolar recruitment (p=0.04), but there was no significant difference between the groups (p=0.073). The alveolar-arterial O2 difference decreased for both groups after the breath stacking (p=0.025) and alveolar recruitment (p=0.03) interventions, and there was no significant difference between the groups (p=0.81). Conclusion Our data suggest that the breath stacking and alveolar recruitment techniques are effective in improving the lung mechanics and gas exchange in patients with acute lung injury. PMID:25028951

Labeled carbon dioxide (C18O2): an indicator gas for phase II in expirograms.

PubMed

Schulz, Holger; Schulz, Anne; Eder, Gunter; Heyder, Joachim

2004-11-01

Carbon dioxide labeled with 18O (C18O2) was used as a tracer gas for single-breath measurements in six anesthetized, mechanically ventilated beagle dogs. C18O2 is taken up quasi-instantaneously in the gas-exchanging region of the lungs but much less so in the conducting airways. Its use allows a clear separation of phase II in an expirogram even from diseased individuals and excludes the influence of alveolar concentration differences. Phase II of a C18O2 expirogram mathematically corresponds to the cumulative distribution of bronchial pathways to be traversed completely in the course of exhalation. The derivative of this cumulative distribution with respect to respired volume was submitted to a power moment analysis to characterize volumetric mean (position), standard deviation (broadness), and skewness (asymmetry) of phase II. Position is an estimate of dead space volume, whereas broadness and skewness are measures of the range and asymmetry of functional airway pathway lengths. The effects of changing ventilatory patterns and of changes in airway size (via carbachol-induced bronchoconstriction) were studied. Increasing inspiratory or expiratory flow rates or tidal volume had only minor influence on position and shape of phase II. With the introduction of a postinspiratory breath hold, phase II was continually shifted toward the airway opening (maximum 45% at 16 s) and became steeper by up to 16%, whereas skewness showed a biphasic response with a moderate decrease at short breath holding and a significant increase at longer breath holds. Stepwise bronchoconstriction decreased position up to 45 +/- 2% and broadness of phase II up to 43 +/- 4%, whereas skewness was increased up to twofold at high-carbachol concentrations. Under all circumstances, position of phase II by power moment analysis and dead space volume by the Fowler technique agreed closely in our healthy dogs. Overall, power moment analysis provides a more comprehensive view on phase II of single-breath expirograms than conventional dead space volume determinations and may be useful for respiratory physiology studies as well as for the study of diseased lungs.

Physiological responses and air consumption during simulated firefighting tasks in a subway system.

PubMed

Williams-Bell, F Michael; Boisseau, Geoff; McGill, John; Kostiuk, Andrew; Hughson, Richard L

2010-10-01

Professional firefighters (33 men, 3 women), ranging in age from 30 to 53 years, participated in a simulation of a subway system search and rescue while breathing from their self-contained breathing apparatus (SCBA). We tested the hypothesis that during this task, established by expert firefighters to be of moderate intensity, the rate of air consumption would exceed the capacity of a nominal 30-min cylinder. Oxygen uptake, carbon dioxide output, and air consumption were measured with a portable breath-by-breath gas exchange analysis system, which was fully integrated with the expired port of the SCBA. The task involved descending a flight of stairs, walking, performing a search and rescue, retreat walking, then ascending a single flight of stairs to a safe exit. This scenario required between 9:56 and 13:24 min:s (mean, 12:10 ± 1:10 min:s) to complete, with an average oxygen uptake of 24.3 ± 4.5 mL kg(-1) min(-1) (47 ± 10 % peak oxygen uptake) and heart rate of 76% ± 7% of maximum. The highest energy requirement was during the final single-flight stair climb (30.4 ± 5.4 mL kg(-1) min(-1)). The average respiratory exchange ratio (carbon dioxide output/oxygen uptake) throughout the scenario was 0.95 ± 0.08, indicating a high carbon dioxide output for a relatively moderate average energy requirement. Air consumption from the nominal "30-min" cylinder averaged 51% (range, 26%-68%); however, extrapolation of these rates of consumption suggested that the low-air alarm, signalling that only 25% of the air remains, would have occurred as early as 11 min for an individual with the highest rate of air consumption, and at 16 min for the group average. These data suggest that even the moderate physical demands of walking combined with search and rescue while wearing full protective gear and breathing through the SCBA impose considerable physiological strain on professional firefighters. As well, the rate of air consumption in these tasks classed as moderate, compared with high-rise firefighting, would have depleted the air supply well before the nominal time used to describe the cylinders.

Nasal and Oral Inspiration during Natural Speech Breathing

ERIC Educational Resources Information Center

Lester, Rosemary A.; Hoit, Jeannette D.

2014-01-01

Purpose: The purpose of this study was to determine the typical pattern for inspiration during speech breathing in healthy adults, as well as the factors that might influence it. Method: Ten healthy adults, 18-45 years of age, performed a variety of speaking tasks while nasal ram pressure, audio, and video recordings were obtained. Inspirations…

Sleep-Disordered Breathing and Cognitive Functioning in Preschool Children with and without Down Syndrome

ERIC Educational Resources Information Center

Joyce, A.; Dimitriou, D.

2017-01-01

Background: Sleep affects children's cognitive development, preparedness for school and future academic outcomes. People with Down syndrome (DS) are particularly at risk for sleep-disordered breathing (SDB). To our knowledge, the association between SDB and cognition in preschoolers with DS is unknown. Methods: We assessed sleep by using…

Performance Validation Approach for the GTX Air-Breathing Launch Vehicle

NASA Technical Reports Server (NTRS)

Trefny, Charles J.; Roche, Joseph M.

2002-01-01

The primary objective of the GTX effort is to determine whether or not air-breathing propulsion can enable a launch vehicle to achieve orbit in a single stage. Structural weight, vehicle aerodynamics, and propulsion performance must be accurately known over the entire flight trajectory in order to make a credible assessment. Structural, aerodynamic, and propulsion parameters are strongly interdependent, which necessitates a system approach to design, evaluation, and optimization of a single-stage-to-orbit concept. The GTX reference vehicle serves this purpose, by allowing design, development, and validation of components and subsystems in a system context. The reference vehicle configuration (including propulsion) was carefully chosen so as to provide high potential for structural and volumetric efficiency, and to allow the high specific impulse of air-breathing propulsion cycles to be exploited. Minor evolution of the configuration has occurred as analytical and experimental results have become available. With this development process comes increasing validation of the weight and performance levels used in system performance determination. This paper presents an overview of the GTX reference vehicle and the approach to its performance validation. Subscale test rigs and numerical studies used to develop and validate component performance levels and unit structural weights are outlined. The sensitivity of the equivalent, effective specific impulse to key propulsion component efficiencies is presented. The role of flight demonstration in development and validation is discussed.

Single-Site Cannulation Venovenous Extracorporeal CO2 Removal as Bridge to Lung Volume Reduction Surgery in End-Stage Lung Emphysema.

PubMed

Redwan, Bassam; Ziegeler, Stephan; Semik, Michael; Fichter, Joachim; Dickgreber, Nicolas; Vieth, Volker; Ernst, Erik Christian; Fischer, Stefan

Lung volume reduction surgery (LVRS) is an important treatment option for end-stage lung emphysema in carefully selected patients. Here, we first describe the application of low-flow venovenous extracorporeal CO2 removal (LFVV-ECCO2R) as bridge to LVRS in patients with end-stage lung emphysema experiencing severe hypercapnia caused by acute failure of the breathing pump. Between March and October 2015, n = 4 patients received single-site LFVV-ECCO2R as bridge to LVRS. Indication for extracorporeal lung support was severe hypercapnia with respiratory acidosis and acute breathing pump failure. Two patients required continuous mechanical ventilation over a temporary tracheostomy and were bed ridden. The other two patients were nearly immobile because of severe dyspnea at rest. Length of preoperative ECCO2R was 14 (1-42) days. All patients underwent unilateral LVRS. Anatomical resection of the right (n = 3) or left (n = 1) upper lobe was performed. Postoperatively, both patients with previous mechanical ventilatory support were successfully weaned. ECCO2R in patients with end-stage lung emphysema experiencing severe hypercapnia caused by acute breathing pump failure is a safe and effective bridging tool to LVRS. In such patients, radical surgery leads to a significant improvement of the performance status and furthermore facilitates respiratory weaning from mechanical ventilation.

Insulin sensitivity index (ISI0, 120) potentially linked to carbon isotopes of breath CO2 for pre-diabetes and type 2 diabetes

PubMed Central

Ghosh, Chiranjit; Mukhopadhyay, Prabuddha; Ghosh, Shibendu; Pradhan, Manik

2015-01-01

New strategies for an accurate and early detection of insulin resistance are important to delay or prevent the acute onset of type 2 diabetes (T2D). Currently, insulin sensitivity index (ISI0,120) is considered to be a viable invasive method of whole-body insulin resistance for use in clinical settings in comparison with other invasive sensitivity indexes like homeostasis model assessment (HOMA), and quantitative insulin sensitivity check index (QUICKI). To investigate how these sensitivity indexes link the 13C/12C-carbon isotopes of exhaled breath CO2 to pre-diabetes (PD) and type 2 diabetes in response to glucose ingestion, we studied excretion dynamics of 13C/12C-isotopic fractionations of breath CO2. Here, we show that 13C/12C-isotope ratios of breath CO2 were well correlated with blood glucose, insulin, glycosylated-hemoglobin as well as with HOMA-IR and 1/QUICKI. Conversely, the strongest correlation was observed between 1/ISI0,120 and breath CO2 isotopes. Consequently, we determined several optimal diagnostic cut-off points of 1/ISI0,120 and 13CO2/12CO2-isotope ratios to distinctively track the evolution of PD prior to the onset of T2D. Our findings suggest that isotopic breath CO2 is a novel method for accurate estimation of ISI0,120 and thus may open new perspectives into the isotope-specific non-invasive evaluation of insulin resistance for large-scale real-time diabetes screening purposes. PMID:26148706

Liver diffusivity in healthy volunteers and patients with chronic liver disease: Comparison of breath-hold and free-breathing techniques

PubMed Central

Eatesam, Mamak; Noworolski, Susan M; Tien, Phyllis C; Nystrom, Michelle; Dodge, Jennifer L.; Merriman, Raphael B.; Qayyum, Aliya

2011-01-01

Purpose To compare liver ADC obtained with breath-hold and free-breathing diffusion weighted imaging (DWI) in healthy volunteers and patients with liver disease. Materials and Methods Twenty-eight subjects, 12 healthy volunteers and 16 patients (9 NAFLD, 7 chronic active HCV), underwent breath-hold (BH) and free-breathing (FB) DWI MRI at 1.5T. Pearson’s correlation coefficient was used to determine correlation while paired t-tests assessed differences between BH and FB ADC. Estimated bias was calculated using the Bland-Altman method. Results Liver ADC (×10−3 mm2/sec) was lower on BH for all groups (mean difference 0.36±0.20; p<0.01). ADC was higher in healthy volunteers (BH 1.80±0.18; FB 2.24±0.20) compared to NAFLD patients (BH 1.43±0.27; FB 1.78±0.28) (p<0.001) and HCV patients (BH 1.63±0.191; FB 1.88±0.12). Overall correlation between BH and FB ADC was (r =0.75), greatest in NAFLD (r =0.90) compared to the correlation in HCV (r =0.24) and healthy subjects (r =0.34). Bland-Altman plots did not show agreement in mean absolute difference and estimated bias between subjects. Conclusion Correlation between BH and FB liver ADC is moderate indicating that BH and FB should not be used interchangeably. Additionally, the lower ADC values in BH versus FB should be accounted for when comparing different liver DWI studies. PMID:22034200

Feasibility of using single photon counting X-ray for lung tumor position estimation based on 4D-CT.

PubMed

Aschenbrenner, Katharina P; Guthier, Christian V; Lyatskaya, Yulia; Boda-Heggemann, Judit; Wenz, Frederik; Hesser, Jürgen W

2017-09-01

In stereotactic body radiation therapy of lung tumors, reliable position estimation of the tumor is necessary in order to minimize normal tissue complication rate. While kV X-ray imaging is frequently used, continuous application during radiotherapy sessions is often not possible due to concerns about the additional dose. Thus, ultra low-dose (ULD) kV X-ray imaging based on a single photon counting detector is suggested. This paper addresses the lower limit of photons to locate the tumor reliably with an accuracy in the range of state-of-the-art methods, i.e. a few millimeters. 18 patient cases with four dimensional CT (4D-CT), which serves as a-priori information, are included in the study. ULD cone beam projections are simulated from the 4D-CTs including Poisson noise. The projections from the breathing phases which correspond to different tumor positions are compared to the ULD projection by means of Poisson log-likelihood (PML) and correlation coefficient (CC), and template matching under these metrics. The results indicate that in full thorax imaging five photons per pixel suffice for a standard deviation in tumor positions of less than half a breathing phase. Around 50 photons per pixel are needed to achieve this accuracy with the field of view restricted to the tumor region. Compared to CC, PML tends to perform better for low photon counts and shifts in patient setup. Template matching only improves the position estimation in high photon counts. The quality of the reconstruction is independent of the projection angle. The accuracy of the proposed ULD single photon counting system is in the range of a few millimeters and therefore comparable to state-of-the-art tumor tracking methods. At the same time, a reduction in photons per pixel by three to four orders of magnitude relative to commercial systems with flatpanel detectors can be achieved. This enables continuous kV image-based position estimation during all fractions since the additional dose to the patient is negligible. Copyright © 2017. Published by Elsevier GmbH.

Music structure determines heart rate variability of singers

PubMed Central

Vickhoff, Björn; Malmgren, Helge; Åström, Rickard; Nyberg, Gunnar; Ekström, Seth-Reino; Engwall, Mathias; Snygg, Johan; Nilsson, Michael; Jörnsten, Rebecka

2013-01-01

Choir singing is known to promote wellbeing. One reason for this may be that singing demands a slower than normal respiration, which may in turn affect heart activity. Coupling of heart rate variability (HRV) to respiration is called Respiratory sinus arrhythmia (RSA). This coupling has a subjective as well as a biologically soothing effect, and it is beneficial for cardiovascular function. RSA is seen to be more marked during slow-paced breathing and at lower respiration rates (0.1 Hz and below). In this study, we investigate how singing, which is a form of guided breathing, affects HRV and RSA. The study comprises a group of healthy 18 year olds of mixed gender. The subjects are asked to; (1) hum a single tone and breathe whenever they need to; (2) sing a hymn with free, unguided breathing; and (3) sing a slow mantra and breathe solely between phrases. Heart rate (HR) is measured continuously during the study. The study design makes it possible to compare above three levels of song structure. In a separate case study, we examine five individuals performing singing tasks (1–3). We collect data with more advanced equipment, simultaneously recording HR, respiration, skin conductance and finger temperature. We show how song structure, respiration and HR are connected. Unison singing of regular song structures makes the hearts of the singers accelerate and decelerate simultaneously. Implications concerning the effect on wellbeing and health are discussed as well as the question how this inner entrainment may affect perception and behavior. PMID:23847555

Underwater study of arterial blood pressure in breath-hold divers.

PubMed

Sieber, Arne; L'abbate, Antonio; Passera, Mirko; Garbella, Erika; Benassi, Antonio; Bedini, Remo

2009-11-01

Knowledge regarding arterial blood pressure (ABP) values during breath-hold diving is scanty. It derives from a few reports of measurements performed at the water's surface, showing slight or no increase in ABP, and from a single study of two simulated deep breath-hold dives in a hyperbaric chamber. Simulated dives showed an increase in ABP to values considered life threatening by standard clinical criteria. For the first time, using a novel noninvasive subaquatic sphygmomanometer, we successfully measured ABP in 10 healthy elite breath-hold divers at a depth of 10 m of freshwater (mfw). ABP was measured in dry conditions, at the surface (head-out immersion), and twice at a depth of 10 mfw. Underwater measurements of ABP were obtained in all subjects. Each measurement lasted 50-60 s and was accomplished without any complications or diver discomfort. In the 10 subjects as a whole, mean ABP values were 124/93 mmHg at the surface and 123/94 mmHg at a depth of 10 mfw. No significant statistical differences were found when blood pressure measurements at the water surface were compared with breath-hold diving conditions at a depth of 10 mfw. No systolic blood pressure values >140 mmHg or diastolic blood pressure values >115 mmHg were recorded. In conclusion, direct measurements of ABP during apnea diving showed no or only mild increases in ABP. However, our results cannot be extended over environmental conditions different from those of the present study.

Frequency of rhinitis and orofacial disorders in patients with dental malocclusion

PubMed Central

Imbaud, Tamara Christine de Souza; Mallozi, Márcia Carvalho; Domingos, Vanda Beatriz Teixeira Coelho; Solé, Dirceu

2016-01-01

Abstract Objective: To describe the frequency and etiology of rhinitis, oral breathing, types of malocclusion and orofacial disorders in patients treated for dental malocclusion. Methods: Patients with poor dental occlusion (n=89, 8-15 years) undergoing orthodontic treatment at the Postgraduate Orthodontics Center (São Paulo, Brazil) participated in the study. Rhinitis and oral breathing were diagnosed by anamnesis, clinical assessment and allergic etiology of rhinitis through immediate hypersensitivity skin prick test with airborne allergens. The association between types of breathing (oral or nasal), rhinitis and types of dental malocclusion, bruxism and cephalometric alterations (increased Y axis of facial growth) compared to standard cephalometric tracing (Escola de Odontologia da Universidade de São Paulo) were assessed. Results: The frequency of rhinitis in patients with dental malocclusion was 76.4% (68), and, of these, 81.7% were allergic (49/60 positive skin prick test), whereas the frequency of oral breathing was 62.9%. There was a significant association between an increased Y axis of facial growth and oral breathing (p<0.001), as well as between oral breathing and rhinitis (p=0.009). There was no association between rhinitis and bruxism. Conclusions: The frequency of rhinitis in children with dental malocclusion is higher than that in the general population, which is approximately 30%. Patients with oral breathing have a tendency to a dolichofacial growth pattern (increased Y axis of facial growth). In patients with rhinitis, regardless of the presence of oral breathing, the dolichofacial growth tendency was not observed. PMID:26631324

Breath carbon stable isotope ratios identify changes in energy balance and substrate utilization in humans.

PubMed

Whigham, L D; Butz, D E; Johnson, L K; Schoeller, D A; Abbott, D H; Porter, W P; Cook, M E

2014-09-01

Rapid detection of shifts in substrate utilization and energy balance would provide a compelling biofeedback tool for individuals attempting weight loss. As a proof of concept, we tested whether the natural abundance of exhaled carbon stable isotope ratios (breath δ(13)C) reflects shifts between negative and positive energy balance. Volunteers (n=5) consumed a 40% energy-restricted diet for 6 days followed by 50% excess on day 7. Breath was sampled immediately before and 1 h and 2 h after breakfast, lunch and dinner. Exhaled breath δ(13)C values were measured by cavity ring-down spectroscopy. Using repeated measures analysis of variance (ANOVA) followed by Dunnett's contrasts, pre-breakfast breath values on days 2-6 were compared with day 1, and postprandial day 7 time points were compared with pre-breakfast day 7. Energy restriction diminished pre-breakfast breath δ(13)C by day 3 (P<0.05). On day 7, increased energy intake was first detected immediately before dinner (-23.8±0.6 vs -21.9±0.7‰, P=0.002 (means±s.d.)), and breath δ(13)C remained elevated at least 2 h post dinner. In conclusion, when shifting between negative and positive energy balance, breath δ(13)C showed anticipated isotopic changes. Although additional research is needed to determine specificity and repeatability, this method may provide a biomarker for marked increases in caloric intake.

Solid-state gas sensors for breath analysis: a review.

PubMed

Di Natale, Corrado; Paolesse, Roberto; Martinelli, Eugenio; Capuano, Rosamaria

2014-05-08

The analysis of volatile compounds is an efficient method to appraise information about the chemical composition of liquids and solids. This principle is applied to several practical applications, such as food analysis where many important features (e.g. freshness) can be directly inferred from the analysis of volatile compounds. The same approach can also be applied to a human body where the volatile compounds, collected from the skin, the breath or in the headspace of fluids, might contain information that could be used to diagnose several kinds of diseases. In particular, breath is widely studied and many diseases can be potentially detected from breath analysis. The most fascinating property of breath analysis is the non-invasiveness of the sample collection. Solid-state sensors are considered the natural complement to breath analysis, matching the non-invasiveness with typical sensor features such as low-cost, easiness of use, portability, and the integration with the information networks. Sensors based breath analysis is then expected to dramatically extend the diagnostic capabilities enabling the screening of large populations for the early diagnosis of pathologies. In the last years there has been an increased attention to the development of sensors specifically aimed to this purpose. These investigations involve both specific sensors designed to detect individual compounds and non-specific sensors, operated in array configurations, aimed at clustering subjects according to their health conditions. In this paper, the recent significant applications of these sensors to breath analysis are reviewed and discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

An Ultrasonic Contactless Sensor for Breathing Monitoring

PubMed Central

Arlotto, Philippe; Grimaldi, Michel; Naeck, Roomila; Ginoux, Jean-Marc

2014-01-01

The monitoring of human breathing activity during a long period has multiple fundamental applications in medicine. In breathing sleep disorders such as apnea, the diagnosis is based on events during which the person stops breathing for several periods during sleep. In polysomnography, the standard for sleep disordered breathing analysis, chest movement and airflow are used to monitor the respiratory activity. However, this method has serious drawbacks. Indeed, as the subject should sleep overnight in a laboratory and because of sensors being in direct contact with him, artifacts modifying sleep quality are often observed. This work investigates an analysis of the viability of an ultrasonic device to quantify the breathing activity, without contact and without any perception by the subject. Based on a low power ultrasonic active source and transducer, the device measures the frequency shift produced by the velocity difference between the exhaled air flow and the ambient environment, i.e., the Doppler effect. After acquisition and digitization, a specific signal processing is applied to separate the effects of breath from those due to subject movements from the Doppler signal. The distance between the source and the sensor, about 50 cm, and the use of ultrasound frequency well above audible frequencies, 40 kHz, allow monitoring the breathing activity without any perception by the subject, and therefore without any modification of the sleep quality which is very important for sleep disorders diagnostic applications. This work is patented (patent pending 2013-7-31 number FR.13/57569). PMID:25140632

Comparison and reproducibility of ADC measurements in breathhold, respiratory triggered, and free-breathing diffusion-weighted MR imaging of the liver.

PubMed

Kwee, Thomas C; Takahara, Taro; Koh, Dow-Mu; Nievelstein, Rutger A J; Luijten, Peter R

2008-11-01

To compare and determine the reproducibility of apparent diffusion coefficient (ADC) measurements of the normal liver parenchyma in breathhold, respiratory triggered, and free-breathing diffusion-weighted magnetic resonance imaging (DWI). Eleven healthy volunteers underwent three series of DWI. Each DWI series consisted of one breathhold, one respiratory triggered, and two free-breathing (thick and thin slice acquisition) scans of the liver, at b-values of 0 and 500 s/mm2. ADCs of the liver parenchyma were compared by using nonparametric tests. Reproducibility was assessed by the Bland-Altman method. Mean ADCs (in 10(-3) mm2/sec) in respiratory triggered DWI (2.07-2.27) were significantly higher than mean ADCs in breathhold DWI (1.57-1.62), thick slice free-breathing DWI (1.62-1.65), and thin slice free-breathing DWI (1.57-1.66) (P<0.005). Ranges of mean difference in ADC measurement+/-limits of agreement between two scans were -0.02-0.05+/-0.16-0.24 in breathhold DWI, -0.14-0.20+/-0.59-0.60 in respiratory triggered DWI, -0.03-0.03+/-0.20-0.29 in thick slice free-breathing DWI, and -0.01-0.09+/-0.21-0.29 in thin slice free-breathing DWI. ADC measurements of the normal liver parenchyma in respiratory triggered DWI are significantly higher and less reproducible than in breathhold and free-breathing DWI. Copyright (c) 2008 Wiley-Liss, Inc.

A method of reconstruction of clinical gas-analyzer signals corrupted by positive-pressure ventilation.

PubMed

Farmery, A D; Hahn, C E

2001-04-01

The use of sidestream infrared and paramagnetic clinical gas analyzers is widespread in anesthesiology and respiratory medicine. For most clinical applications, these instruments are entirely satisfactory. However, their ability to measure breath-by-breath volumetric gas fluxes, as required for measurement of airway dead space, oxygen uptake, and so on, is usually inferior to that of the mass spectrometer, and this is thought to be due, in part, to their slower response times. We describe how volumetric gas analysis with the Datex Ultima analyzer, although reasonably accurate for spontaneous ventilation, gives very inaccurate results in conditions of positive-pressure ventilation. We show that this problem is a property of the gas sampling system rather than the technique of gas analysis itself. We examine the source of this error and describe how cyclic changes in airway pressure result in variations in the flow rate of the gas within the sampling catheter. This results in the phenomenon of "time distortion," and the resultant gas concentration signal becomes a nonlinear time series. This corrupted signal cannot be aligned or integrated with the measured flow signal. We describe a method to correct for this effect. With the use of this method, measurements required for breath-by-breath gas-exchange models can be made easily and reliably in the clinical setting.

A simple, remote, video based breathing monitor.

PubMed

Regev, Nir; Wulich, Dov

2017-07-01

Breathing monitors have become the all-important cornerstone of a wide variety of commercial and personal safety applications, ranging from elderly care to baby monitoring. Many such monitors exist in the market, some, with vital signs monitoring capabilities, but none remote. This paper presents a simple, yet efficient, real time method of extracting the subject's breathing sinus rhythm. Points of interest are detected on the subject's body, and the corresponding optical flow is estimated and tracked using the well known Lucas-Kanade algorithm on a frame by frame basis. A generalized likelihood ratio test is then utilized on each of the many interest points to detect which is moving in harmonic fashion. Finally, a spectral estimation algorithm based on Pisarenko harmonic decomposition tracks the harmonic frequency in real time, and a fusion maximum likelihood algorithm optimally estimates the breathing rate using all points considered. The results show a maximal error of 1 BPM between the true breathing rate and the algorithm's calculated rate, based on experiments on two babies and three adults.

Real-time volumetric image reconstruction and 3D tumor localization based on a single x-ray projection image for lung cancer radiotherapy.

PubMed

Li, Ruijiang; Jia, Xun; Lewis, John H; Gu, Xuejun; Folkerts, Michael; Men, Chunhua; Jiang, Steve B

2010-06-01

To develop an algorithm for real-time volumetric image reconstruction and 3D tumor localization based on a single x-ray projection image for lung cancer radiotherapy. Given a set of volumetric images of a patient at N breathing phases as the training data, deformable image registration was performed between a reference phase and the other N-1 phases, resulting in N-1 deformation vector fields (DVFs). These DVFs can be represented efficiently by a few eigenvectors and coefficients obtained from principal component analysis (PCA). By varying the PCA coefficients, new DVFs can be generated, which, when applied on the reference image, lead to new volumetric images. A volumetric image can then be reconstructed from a single projection image by optimizing the PCA coefficients such that its computed projection matches the measured one. The 3D location of the tumor can be derived by applying the inverted DVF on its position in the reference image. The algorithm was implemented on graphics processing units (GPUs) to achieve real-time efficiency. The training data were generated using a realistic and dynamic mathematical phantom with ten breathing phases. The testing data were 360 cone beam projections corresponding to one gantry rotation, simulated using the same phantom with a 50% increase in breathing amplitude. The average relative image intensity error of the reconstructed volumetric images is 6.9% +/- 2.4%. The average 3D tumor localization error is 0.8 +/- 0.5 mm. On an NVIDIA Tesla C1060 GPU card, the average computation time for reconstructing a volumetric image from each projection is 0.24 s (range: 0.17 and 0.35 s). The authors have shown the feasibility of reconstructing volumetric images and localizing tumor positions in 3D in near real-time from a single x-ray image.

Lung cancer detection by proton transfer reaction mass-spectrometric analysis of human breath gas

NASA Astrophysics Data System (ADS)

Wehinger, Andreas; Schmid, Alex; Mechtcheriakov, Sergei; Ledochowski, Maximilian; Grabmer, Christoph; Gastl, Guenther A.; Amann, Anton

2007-08-01

Background Determination of the diagnostic usefulness of proton transfer reaction mass spectrometry (PTR-MS) for detecting primary lung cancer through analysis of volatile organic compounds (VOCs) in exhaled human breath was demonstrated in this investigation. Unlike, for example, gas-chromatographic analyses, PTR-MS can be used without time-consuming preconcentration of the gas samples.Methods By means of PTR-MS, exhaled breath samples from primary lung cancer patients (n = 17) were analyzed and compared with both an overall control collective (controls total, n = 170) and three sub-collectives: hospital personnel (controls hospital, n = 35), age-matched persons (controls age, n = 25), and smokers (controls s, n = 60), respectively.Results Among the VOCs present at reasonably high concentrations, the ones leading to the product ion at m/z = 31 (VOC-31, tentatively protonated formaldehyde) and m/z = 43 (VOC-43, tentatively a fragment of protonated iso-propanol), were found at significantly higher concentrations in the breath gas of the primary lung cancer patients as compared to the healthy controls at the following median concentrations (with interquartile distance, iqr): For VOC-31 the median concentrations were 7.0 ppb (iqr, 15.5 ppb) versus 3.0 ppb (iqr, 1.9 ppb) with P < 10-4. For VOC-43 the median concentrations were 244.1 ppb (iqr, 236.2 ppb) versus 94.1 ppb (iqr, 55.2 ppb) with P < 10-6. The discriminative power between the two collectives was further assessed by ROC-curves obtained upon variation of the chosen threshold concentration and by Fisher's Quadratic Discriminant Method.Conclusions Within the limits of pilot study, VOC-31 and -43 were found to best discriminate between exhaled breath of primary lung cancer cases and healthy controls. Simple and time-saving breath gas analysis by PTR-MS makes this method attractive for a larger clinical evaluation. It may become a new valuable tool for diagnosing primary lung cancer.

Bioavailability of organic solvents in soils: Input into biologically based dose-response models for human risk assessments. 1998 annual progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wester, R.C.; Maibach, H.I.

1998-06-01

'The purpose of this study is to determine the bioavailability of organic solvents following dermal exposures to contaminated soil and water. Breath analysis is being used to obtain real-time measurements of volatile organics in expired air following exposure in rats and humans. Rhesus monkeys will be used as surrogates for humans in benzene exposures. The exhaled breath data is being analyzed using physiologically based pharmacokinetic (PBPK) models to determine the dermal bioavailability of organic solvents under realistic exposure conditions. The end product of this research will be a tested framework for the rapid screening of real and potential exposures whilemore » simultaneously developing physiologically based pharmacokinetic (PBPK) models to comprehensively evaluate and compare exposures to organics from either contaminated soil or water. This report summarizes work 7 months into a 3-year project. Method development has produced systems for solvent exposure from soil and water which mimic actual exposure, and for which animals and human volunteers can be safely tested. Soil exposure is generally open to the air (working the soil) while water exposure is generally immersion. For 6--8 hour test exposure, a patch has been developed where soil is contained against the skin by a non-occlusive membrane, while simultaneously allowing volatilization of test solvent to the environment (activated charcoal). The water counterpart is an occlusive glass culture dish, sealed to skin with silicone adhesive. Shorter term exposure is done by one hand immersion in a bucket containing circulating water or soil, the volunteer instructed to move fingers through the water or soil. Human volunteers and animals breathe fresh air via a new breath-inlet system that allows for continuous real-time analysis of undiluted exhaled air. The air supply system is self-contained and separated from the exposure solvent-laden environment. The system uses a Teledyne 3DQ Discovery ion trap mass spectrometer (MS/MS) equipped with an atmospheric sampling glow discharge ionization source (ASGDI). The MS/MS system provides an appraisal of individual chemical components in the breath stream in the single-digit parts-per-billion (ppb) detectable range for each of the compounds proposed for study, while maintaining linearity of response over a wide dynamic range.'« less

Bench experiments comparing simulated inspiratory effort when breathing helium-oxygen mixtures to that during positive pressure support with air

PubMed Central

2012-01-01

Background Inhalation of helium-oxygen (He/O2) mixtures has been explored as a means to lower the work of breathing of patients with obstructive lung disease. Non-invasive ventilation (NIV) with positive pressure support is also used for this purpose. The bench experiments presented herein were conducted in order to compare simulated patient inspiratory effort breathing He/O2 with that breathing medical air, with or without pressure support, across a range of adult, obstructive disease patterns. Methods Patient breathing was simulated using a dual-chamber mechanical test lung, with the breathing compartment connected to an ICU ventilator operated in NIV mode with medical air or He/O2 (78/22 or 65/35%). Parabolic or linear resistances were inserted at the inlet to the breathing chamber. Breathing chamber compliance was also varied. The inspiratory effort was assessed for the different gas mixtures, for three breathing patterns, with zero pressure support (simulating unassisted spontaneous breathing), and with varying levels of pressure support. Results Inspiratory effort increased with increasing resistance and decreasing compliance. At a fixed resistance and compliance, inspiratory effort increased with increasing minute ventilation, and decreased with increasing pressure support. For parabolic resistors, inspiratory effort was lower for He/O2 mixtures than for air, whereas little difference was measured for nominally linear resistance. Relatively small differences in inspiratory effort were measured between the two He/O2 mixtures. Used in combination, reductions in inspiratory effort provided by He/O2 and pressure support were additive. Conclusions The reduction in inspiratory effort afforded by breathing He/O2 is strongly dependent on the severity and type of airway obstruction. Varying helium concentration between 78% and 65% has small impact on inspiratory effort, while combining He/O2 with pressure support provides an additive reduction in inspiratory effort. In addition, breathing He/O2 alone may provide an alternative to pressure support in circumstances where NIV is not available or poorly tolerated. PMID:23031537

Breath air measurement using wide-band frequency tuning IR laser photo-acoustic spectroscopy

NASA Astrophysics Data System (ADS)

Kistenev, Yury V.; Borisov, Alexey V.; Kuzmin, Dmitry A.; Bulanova, Anna A.; Boyko, Andrey A.; Kostyukova, Nadezhda Y.; Karapuzikov, Alexey A.

2016-03-01

The results of measuring of biomarkers in breath air of patients with broncho-pulmonary diseases using wide-band frequency tuning IR laser photo-acoustic spectroscopy and the methods of data mining are presented. We will discuss experimental equipment and various methods of intellectual analysis of the experimental spectra in context of above task. The work was carried out with partial financial support of the FCPIR contract No 14.578.21.0082 (ID RFMEFI57814X0082).

[Analysis of breath hydrogen (H2) in diagnosis of gastrointestinal function: validation of a pocket breath H2 test analyzer].

PubMed

Braden, B; Braden, C P; Klutz, M; Lembcke, B

1993-04-01

Breath hydrogen (H2) analysis, as used in gastroenterologic function tests, requires a stationary analysis system equipped with a gaschromatograph or an electrochemical sensor cell. Now a portable breath H2-analyzer has been miniaturized to pocket size (104 mm x 62 mm x 29 mm). The application of this device in clinical practice has been assessed in comparison to the standard GMI-exhaled monitor. The pocket analyzer showed a linear response to standards with H2-concentrations ranging from 0-100 ppm (n = 7), which was not different from the GMI-apparatus. The correlation of both methods during clinical application (lactose tolerance tests, mouth-to-coecum transit time determined with lactulose) was excellent (Y = 1.08 X + 0.96; r = 0.959). Using the new device, both, analysis (3 s vs. 90 s) and the reset-time (43 s vs. 140 s) were shorter whereas calibration was more feasible with the GMI-apparatus. It is concluded, that the considerably cheaper pocket-sized breath H2-analyzer is as precise and sensitive as the GMI-exhaled monitor, and thus presents a valid alternative for H2-breath tests.

Determination of volatile organic compounds in human breath for Helicobacter pylori detection by SPME-GC/MS.

PubMed

Ulanowska, Agnieszka; Kowalkowski, Tomasz; Hrynkiewicz, Katarzyna; Jackowski, Marek; Buszewski, Bogusław

2011-03-01

Helicobacter pylori living in the human stomach release volatile organic compounds (VOCs) that can be detected in expired air. The aim of the study was the application of breath analysis for bacteria detection. It was accomplished by determination of VOCs characteristic for patients with H. pylori and the analysis of gases released by bacteria in suspension. Solid-phase microextraction was applied as a selective technique for preconcentration and isolation of analytes. Gas chromatography coupled with mass spectrometry was used for the separation and identification of volatile analytes in breath samples and bacterial headspace. For data calculation and processing, discriminant and factor analyses were used. Endogenous substances such as isobutane, 2-butanone and ethyl acetate were detected in the breath of persons with H. pylori in the stomach and in the gaseous mixture released by the bacteria strain but they were not identified in the breath of healthy volunteers. The canonical analysis of discrimination functions showed a strong difference between the three examined groups. Knowledge of substances emitted by H. pylori with the application of an optimized breath analysis method might become a very useful tool for noninvasive detection of this bacterium. Copyright © 2010 John Wiley & Sons, Ltd.

Removing respiratory artefacts from transthoracic bioimpedance spectroscopy measurements

NASA Astrophysics Data System (ADS)

Cuba-Gyllensten, I.; Abtahi, F.; Bonomi, A. G.; Lindecrantz, K.; Seoane, F.; Amft, O.

2013-04-01

Transthoracic impedance spectroscopy (TIS) measurements from wearable textile electrodes provide a tool to remotely and non-invasively monitor patient health. However, breathing and cardiac processes inevitably affect TIS measurements, since they are sensitive to changes in geometry and air or fluid volumes in the thorax. This study aimed at investigating the effect of respiration on Cole parameters extracted from TIS measurements and developing a method to suppress artifacts. TIS data were collected from 10 participants at 16 frequencies (range: 10 kHz - 1 MHz) using a textile electrode system (Philips Technologie Gmbh). Simultaneously, breathing volumes and frequency were logged using an electronic spirometer augmented with data from a breathing belt. The effect of respiration on TIS measurements was studied at paced (10 and 16 bpm) deep and shallow breathing. These measurements were repeated for each subject in three different postures (lying down, reclining and sitting). Cole parameter estimation was improved by assessing the tidal expiration point thus removing breathing artifacts. This leads to lower intra-subject variability between sessions and a need for less measurements points to accurately assess the spectra. Future work should explore algorithmic artifacts compensation models using breathing and posture or patient contextual information to improve ambulatory transthoracic impedance measurements.

Optical fiber sensors for breathing diagnostics

NASA Astrophysics Data System (ADS)

Chen, Q.; Claus, Richard O.; Mecham, Jeffrey B.; Vercellino, M.; Arregui, Francisco J.; Matias, Ignacio R.

2002-03-01

We report the application of an optical fiber-based humidity sensor to the problem of breathing diagnostics. The sensor is fabricated by molecularly self-assembling selected polymers and functionalized inorganic nanoclusters into multilayered optical thin films on the cleaved and polished flat end of a singlemode optical fiber. Prior work has studied the synthesis process and the fundamental mechanisms responsible for the change in optical reflection from the film that occurs as a function of humidity. We will briefly review that prior work as a way to introduce more recent developments. This paper will then discuss the application of these sensors to the analysis of air flow. We have designed the sensor thin film materials for the detection of relative humidity over a wide range, from approximately 10 to 95%, and for response times as short as several tens of milliseconds. This very fast response time allows the near real-time analysis of air flow and humidity during a single breath, with the advantage of very small size.

Heat Exchanger Design in Combined Cycle Engines

NASA Astrophysics Data System (ADS)

Webber, H.; Feast, S.; Bond, A.

Combined cycle engines employing both pre-cooled air-breathing and rocket modes of operation are the most promising propulsion system for achieving single stage to orbit vehicles. The air-breathing phase is purely for augmentation of the mission velocity required in the rocket phase and as such must be mass effective, re-using the components of the rocket cycle, whilst achieving adequate specific impulse. This paper explains how the unique demands placed on the air-breathing cycle results in the need for sophisticated thermodynamics and the use of a series of different heat exchangers to enable precooling and high pressure ratio compression of the air for delivery to the rocket combustion chambers. These major heat exchanger roles are; extracting heat from incoming air in the precooler, topping up cycle flow temperatures to maintain constant turbine operating conditions and extracting rejected heat from the power cycle via regenerator loops for thermal capacity matching. The design solutions of these heat exchangers are discussed.

The Sensitivity of Precooled Air-Breathing Engine Performance to Heat Exchanger Design Parameters

NASA Astrophysics Data System (ADS)

Webber, H.; Bond, A.; Hempsell, M.

The issues relevant to propulsion design for Single Stage To Orbit (SSTO) vehicles are considered. In particular two air- breathing engine concepts involving precooling are compared; SABRE (Synergetic Air-Breathing and Rocket Engine) as designed for the Skylon SSTO launch vehicle, and a LACE (Liquid Air Cycle Engine) considered in the 1960's by the Americans for an early generation spaceplane. It is shown that through entropy minimisation the SABRE has made substantial gains in performance over the traditional LACE precooled engine concept, and has shown itself as the basis of a viable means of realising a SSTO vehicle. Further, it is demonstrated that the precooler is a major source of thermodynamic irreversibility within the engine cycle and that further reduction in entropy can be realised by increasing the heat transfer coefficient on the air side of the precooler. If this were to be achieved, it would improve the payload mass delivered to orbit by the Skylon launch vehicle by between 5 and 10%.

Enhancing the sensitivity of mid-IR quantum cascade laser-based cavity-enhanced absorption spectroscopy using RF current perturbation.

PubMed

Manfred, Katherine M; Kirkbride, James M R; Ciaffoni, Luca; Peverall, Robert; Ritchie, Grant A D

2014-12-15

The sensitivity of mid-IR quantum cascade laser (QCL) off-axis cavity-enhanced absorption spectroscopy (CEAS), often limited by cavity mode structure and diffraction losses, was enhanced by applying a broadband RF noise to the laser current. A pump-probe measurement demonstrated that the addition of bandwidth-limited white noise effectively increased the laser linewidth, thereby reducing mode structure associated with CEAS. The broadband noise source offers a more sensitive, more robust alternative to applying single-frequency noise to the laser. Analysis of CEAS measurements of a CO(2) absorption feature at 1890  cm(-1) averaged over 100 ms yielded a minimum detectable absorption of 5.5×10(-3)  Hz(-1/2) in the presence of broadband RF perturbation, nearly a tenfold improvement over the unperturbed regime. The short acquisition time makes this technique suitable for breath applications requiring breath-by-breath gas concentration information.

A stochastic convolution/superposition method with isocenter sampling to evaluate intrafraction motion effects in IMRT.

PubMed

Naqvi, Shahid A; D'Souza, Warren D

2005-04-01

Current methods to calculate dose distributions with organ motion can be broadly classified as "dose convolution" and "fluence convolution" methods. In the former, a static dose distribution is convolved with the probability distribution function (PDF) that characterizes the motion. However, artifacts are produced near the surface and around inhomogeneities because the method assumes shift invariance. Fluence convolution avoids these artifacts by convolving the PDF with the incident fluence instead of the patient dose. In this paper we present an alternative method that improves the accuracy, generality as well as the speed of dose calculation with organ motion. The algorithm starts by sampling an isocenter point from a parametrically defined space curve corresponding to the patient-specific motion trajectory. Then a photon is sampled in the linac head and propagated through the three-dimensional (3-D) collimator structure corresponding to a particular MLC segment chosen randomly from the planned IMRT leaf sequence. The photon is then made to interact at a point in the CT-based simulation phantom. Randomly sampled monoenergetic kernel rays issued from this point are then made to deposit energy in the voxels. Our method explicitly accounts for MLC-specific effects (spectral hardening, tongue-and-groove, head scatter) as well as changes in SSD with isocentric displacement, assuming that the body moves rigidly with the isocenter. Since the positions are randomly sampled from a continuum, there is no motion discretization, and the computation takes no more time than a static calculation. To validate our method, we obtained ten separate film measurements of an IMRT plan delivered on a phantom moving sinusoidally, with each fraction starting with a random phase. For 2 cm motion amplitude, we found that a ten-fraction average of the film measurements gave an agreement with the calculated infinite fraction average to within 2 mm in the isodose curves. The results also corroborate the existing notion that the interfraction dose variability due to the interplay between the MLC motion and breathing motion averages out over typical multifraction treatments. Simulation with motion waveforms more representative of real breathing indicate that the motion can produce penumbral spreading asymmetric about the static dose distributions. Such calculations can help a clinician decide to use, for example, a larger margin in the superior direction than in the inferior direction. In the paper we demonstrate that a 15 min run on a single CPU can readily illustrate the effect of a patient-specific breathing waveform, and can guide the physician in making informed decisions about margin expansion and dose escalation.

Assessing breathing motion by shape matching of lung and diaphragm surfaces

NASA Astrophysics Data System (ADS)

Urschler, Martin; Bischof, Horst

2005-04-01

Studying complex thorax breating motion is an important research topic for accurate fusion of functional and anatomical data, radiotherapy planning or reduction of breathing motion artifacts. We investigate segmented CT lung, airway and diaphragm surfaces at several different breathing states between Functional Residual and Total Lung Capacity. In general, it is hard to robustly derive corresponding shape features like curvature maxima from lung and diaphragm surfaces since diaphragm and rib cage muscles tend to deform the elastic lung tissue such that e.g. ridges might disappear. A novel registration method based on the shape context approach for shape matching is presented where we extend shape context to 3D surfaces. The shape context approach was reported as a promising method for matching 2D shapes without relying on extracted shape features. We use the point correspondences for a non-rigid thin-plate-spline registration to get deformation fields that describe the movement of lung and diaphragm. Our validation consists of experiments on phantom and real sheep thorax data sets. Phantom experiments make use of shapes that are manipulated with known transformations that simulate breathing behaviour. Real thorax data experiments use a data set showing lungs and diaphragm at 5 distinct breathing states, where we compare subsets of the data sets and qualitatively and quantitatively asses the registration performance by using manually identified corresponding landmarks.

Detection of bronchial breathing caused by pneumonia.

PubMed

Gross, V; Fachinger, P; Penzel, Th; Koehler, U; von Wichert, P; Vogelmeier, C

2002-06-01

The classic auscultation with stethoscope is the established clinical method for the detection of lung diseases. The interpretation of the sounds depends on the experience of the investigating physician. Therefore, a new computer-based method has been developed to classify breath sounds from digital lung sound recordings. Lung sounds of 11 patients with one-sided pneumonia and bronchial breathing were recorded on both the pneumonia side and on contralateral healthy side simultaneously using two microphones. The spectral power for the 300-600 Hz frequency band was computed for four respiratory cycles and normalized. For each breath, the ratio R between the time-segments (duration = 0.1 s) with the highest inspiratory and highest expiratory flow was calculated and averaged. We found significant differences in R between the pneumonia side (R = 1.4 +/- 1.3) and the healthy side (R = 0.5 +/- 0.5; p = 0.003 Wilcoxon-test) of lung. In 218 healthy volunteers we found R = 0.3 +/- 0.2 as a reference-value. The differences of ratio R (delta R) between the pneumonia side and the healthy side (delta R = 1.0 +/- 0.9) were significantly higher compared to follow-up studies after recovery (delta R = 0.0 +/- 0.1, p = 0.005 Wilcoxon-test). The computer based detection of bronchial breathing can be considered useful as part of a quantitative monitoring of patients at risk to develop pneumonia.

Exploring the Waveform Characteristics of Tidal Breathing Carbon Dioxide, Measured Using the N-Tidal C Device in Different Breathing Conditions (The General Breathing Record Study): Protocol for an Observational, Longitudinal Study

PubMed Central

Rupani, Hitasha; Kalra, Paul R; Adeniji, Kayode; Quint, Matthew; De Vos, Ruth; Begum, Selina; Mottershaw, Mark; Fogg, Carole; Jones, Thomas L; Lanning, Eleanor; Bassett, Paul; Chauhan, Anoop J

2018-01-01

Background In an increasingly comorbid population, there are significant challenges to diagnosing the cause of breathlessness, and once diagnosed, considerable difficulty in detecting deterioration early enough to provide effective intervention. The burden of the breathless patient on the health care economy is substantial, with asthma, chronic heart failure, and pneumonia affecting over 6 million people in the United Kingdom alone. Furthermore, these patients often have more than one contributory factor to their breathlessness symptoms, with conditions such as dysfunctional breathing pattern disorders—an under-recognized component. Current methods of diagnosing and monitoring breathless conditions can be extensive and difficult to perform. As a consequence, home monitoring is poorly complied with. In contrast, capnography (the measurement of tidal breath carbon dioxide) is performed during normal breathing. There is a need for a simple, easy-to-use, personal device that can aid in the diagnosis and monitoring of respiratory and cardiac causes of breathlessness. Objective The aim of this study was to explore the use of a new, handheld capnometer (called the N-Tidal C) in different conditions that cause breathlessness. We will study whether the tidal breath carbon dioxide (TBCO2) waveform, as measured by the N-Tidal C, has different characteristics in a range of respiratory and cardiac conditions. Methods We will perform a longitudinal, observational study of the TBCO2 waveform (capnogram) as measured by the N-Tidal C capnometer. Participants with a confirmed diagnosis of asthma, breathing pattern disorders, chronic heart failure, motor neurone disease, pneumonia, as well as volunteers with no history of lung disease will be asked to provide twice daily, 75-second TBCO2 collection via the N-Tidal C device for 6 months duration. The collated capnograms will be correlated with the underlying diagnosis and disease state (stable or exacerbation) to determine if there are different TBCO2 characteristics that can distinguish different respiratory and cardiac causes of breathlessness. Results This study’s recruitment is ongoing. It is anticipated that the results will be available in late 2018. Conclusions The General Breathing Record Study will provide an evaluation of the use of capnography as a diagnostic and home-monitoring tool for various diseases. Registered Report Identifier RR1-10.2196/9767 PMID:29798833

TH-CD-202-09: Free-Breathing Proton MRI Functional Lung Avoidance Maps to Guide Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capaldi, D; Sheikh, K; Parraga, G

Purpose: Pulmonary functional MRI using inhaled gas contrast agents was previously investigated as a way to identify well-functioning lung in patients with NSCLC who are clinical candidates for radiotherapy. Hyperpolarized noble-gas ({sup 3}He and {sup 129}Xe) MRI has also been optimized to measure functional lung information, but for a number of reasons, the clinical translation of this approach to guide radiotherapy planning has been limited. As an alternative, free-breathing pulmonary 1H MRI using clinically available MRI systems and pulse sequences provides a non-contrast-enhanced method to generate both ventilation and perfusion maps. Free-breathing {sup 1}H MRI exploits non-rigid registration and Fouriermore » decomposition of MRI signal intensity differences (Bauman et al., MRM, 2009) that may be generated during normal tidal breathing. Here, our objective was to generate free-breathing {sup 1}H MRI ventilation and lung function avoidance maps in patients with NSCLC as a way to guide radiation therapy planning. Methods: Stage IIIA/IIIB NSCLC patients (n=8, 68±9yr) provided written informed consent to a randomized controlled clinical trial ( https://clinicaltrials.gov/ct2/show/NCT02002052 ) that aimed to compare outcomes related to image-guided versus conventional radiation therapy planning. Hyperpolarized {sup 3}He/{sup 129}Xe and dynamic free tidal-breathing {sup 1}H MRI were acquired as previously described (Capaldi et al., Acad Radiol, 2015). Non-rigid registration was performed using the modality-independent-neighbourhood-descriptor (MIND) deformable approach (Heinrich et al., Med Image Anal, 2012). Ventilation-defect-percent ({sup 3}He:VDP{sub He}, {sup 129}Xe:VDP{sub Xe}, Free-breathing-{sup 1}H:VDP{sub FB}) and the corresponding ventilation maps were compared using Pearson correlation coefficients (r) and the Dice similarity coefficient (DSC). Results: VDP{sub FB} was significantly related to VDP{sub He} (r=.71; p=.04) and VDP{sub Xe} (r=.80; p=.01) and there were also strong spatial relationships (DSC{sub He}/DSC{sub Xe}=89±3%/77±11%). Conclusion: In this proof of concept study in NSCLC patients, free-breathing {sup 1}H MRI ventilation defects were quantitatively and spatially related to inhaled-noble-gas MRI ventilation defects. Free-breathing {sup 1}H MRI measures lung function/ventilation that can be used to optimize radiotherapy planning in NSCLC patients.« less

Methods used to calculate doses resulting from inhalation of Capstone depleted uranium aerosols.

PubMed

Miller, Guthrie; Cheng, Yung Sung; Traub, Richard J; Little, Tom T; Guilmette, Raymond A

2009-03-01

The methods used to calculate radiological and toxicological doses to hypothetical persons inside either a U.S. Army Abrams tank or Bradley Fighting Vehicle that has been perforated by depleted uranium munitions are described. Data from time- and particle-size-resolved measurements of depleted uranium aerosol as well as particle-size-resolved measurements of aerosol solubility in lung fluids for aerosol produced in the breathing zones of the hypothetical occupants were used. The aerosol was approximated as a mixture of nine monodisperse (single particle size) components corresponding to particle size increments measured by the eight stages plus the backup filter of the cascade impactors used. A Markov Chain Monte Carlo Bayesian analysis technique was employed, which straightforwardly calculates the uncertainties in doses. Extensive quality control checking of the various computer codes used is described.

An Electrochemical Gas Biosensor Based on Enzymes Immobilized on Chromatography Paper for Ethanol Vapor Detection.

PubMed

Kuretake, Tatsumi; Kawahara, Shogo; Motooka, Masanobu; Uno, Shigeyasu

2017-02-01

This paper presents a novel method of fabricating an enzymatic biosensor for breath analysis using chromatography paper as enzyme supporting layer and a liquid phase layer on top of screen printed carbon electrodes. We evaluated the performance with ethanol vapor being one of the breathing ingredients. The experimental results show that our sensor is able to measure the concentration of ethanol vapor within the range of 50 to 500 ppm. These results suggest the ability of detecting breath ethanol, and it can possibly be applied as a generic vapor biosensor to a wide range of diseases.

Off-axis integrated cavity output spectroscopy with a mid-infrared interband cascade laser for real-time breath ethane measurements.

PubMed

Parameswaran, Krishnan R; Rosen, David I; Allen, Mark G; Ganz, Alan M; Risby, Terence H

2009-02-01

Cavity-enhanced tunable diode laser absorption spectroscopy is an attractive method for measuring small concentrations of gaseous species. Ethane is a breath biomarker of lipid peroxidation initiated by reactive oxygen species. A noninvasive means of quickly quantifying oxidative stress status has the potential for broad clinical application. We present a simple, compact system using off-axis integrated cavity output spectroscopy with an interband cascade laser and demonstrate its use in real-time measurements of breath ethane. We demonstrate a detection sensitivity of 0.48 ppb/Hz(1/2).

Effect of physical therapy scoliosis specific exercises using breathing pattern on adolescent idiopathic scoliosis.

PubMed

Yoon, Sungyoung; Rhee, Min-Hyung

2016-11-01

[Purpose] This study was performed to confirm physical therapy scoliosis specific exercises on adolescent idiopathic scoliosis patients. [Subject and Methods] A 15-year-old male middle school student with scoliosis. Cobb's angle, angle of rotation of the spine, and breathing pattern were measured before and after 8 weeks training. [Results] After 8 weeks training, Cobb's angle, angle of rotation of the spine, and breathing pattern were improved better. [Conclusion] These results indicate that physical therapy scoliosis specific exercises improves scoliosis curves and could provide an effective intervention and management of scoliosis.

Dose-dependent social-cognitive effects of intranasal oxytocin delivered with novel Breath Powered device in adults with autism spectrum disorder: a randomized placebo-controlled double-blind crossover trial

PubMed Central

Quintana, D S; Westlye, L T; Hope, S; Nærland, T; Elvsåshagen, T; Dørum, E; Rustan, Ø; Valstad, M; Rezvaya, L; Lishaugen, H; Stensønes, E; Yaqub, S; Smerud, K T; Mahmoud, R A; Djupesland, P G; Andreassen, O A

2017-01-01

The neuropeptide oxytocin has shown promise as a treatment for symptoms of autism spectrum disorders (ASD). However, clinical research progress has been hampered by a poor understanding of oxytocin’s dose–response and sub-optimal intranasal delivery methods. We examined two doses of oxytocin delivered using a novel Breath Powered intranasal delivery device designed to improve direct nose-to-brain activity in a double-blind, crossover, randomized, placebo-controlled trial. In a randomized sequence of single-dose sessions, 17 male adults with ASD received 8 international units (IU) oxytocin, 24IU oxytocin or placebo followed by four social-cognitive tasks. We observed an omnibus main effect of treatment on the primary outcome measure of overt emotion salience as measured by emotional ratings of faces (η2=0.18). Compared to placebo, 8IU treatment increased overt emotion salience (P=0.02, d=0.63). There was no statistically significant increase after 24IU treatment (P=0.12, d=0.4). The effects after 8IU oxytocin were observed despite no significant increase in peripheral blood plasma oxytocin concentrations. We found no significant effects for reading the mind in the eyes task performance or secondary outcome social-cognitive tasks (emotional dot probe and face-morphing). To our knowledge, this is the first trial to assess the dose-dependent effects of a single oxytocin administration in autism, with results indicating that a low dose of oxytocin can significantly modulate overt emotion salience despite minimal systemic exposure. PMID:28534875

Dose-dependent social-cognitive effects of intranasal oxytocin delivered with novel Breath Powered device in adults with autism spectrum disorder: a randomized placebo-controlled double-blind crossover trial.

PubMed

Quintana, D S; Westlye, L T; Hope, S; Nærland, T; Elvsåshagen, T; Dørum, E; Rustan, Ø; Valstad, M; Rezvaya, L; Lishaugen, H; Stensønes, E; Yaqub, S; Smerud, K T; Mahmoud, R A; Djupesland, P G; Andreassen, O A

2017-05-23

The neuropeptide oxytocin has shown promise as a treatment for symptoms of autism spectrum disorders (ASD). However, clinical research progress has been hampered by a poor understanding of oxytocin's dose-response and sub-optimal intranasal delivery methods. We examined two doses of oxytocin delivered using a novel Breath Powered intranasal delivery device designed to improve direct nose-to-brain activity in a double-blind, crossover, randomized, placebo-controlled trial. In a randomized sequence of single-dose sessions, 17 male adults with ASD received 8 international units (IU) oxytocin, 24IU oxytocin or placebo followed by four social-cognitive tasks. We observed an omnibus main effect of treatment on the primary outcome measure of overt emotion salience as measured by emotional ratings of faces (η 2 =0.18). Compared to placebo, 8IU treatment increased overt emotion salience (P=0.02, d=0.63). There was no statistically significant increase after 24IU treatment (P=0.12, d=0.4). The effects after 8IU oxytocin were observed despite no significant increase in peripheral blood plasma oxytocin concentrations. We found no significant effects for reading the mind in the eyes task performance or secondary outcome social-cognitive tasks (emotional dot probe and face-morphing). To our knowledge, this is the first trial to assess the dose-dependent effects of a single oxytocin administration in autism, with results indicating that a low dose of oxytocin can significantly modulate overt emotion salience despite minimal systemic exposure.

Multishot EPI-SSFP in the heart.

PubMed

Herzka, Daniel A; Kellman, Peter; Aletras, Anthony H; Guttman, Michael A; McVeigh, Elliot R

2002-04-01

Refocused steady-state free precession (SSFP), or fast imaging with steady precession (FISP or TrueFISP), has recently proven valuable for cardiac imaging because of its high signal-to-noise ratio (SNR) and excellent blood-myocardium contrast. In this study, various implementations of multiecho SSFP or EPI-SSFP for imaging in the heart are presented. EPI-SSFP has higher scan-time efficiency than single-echo SSFP, as two or more phase-encode lines are acquired per repetition time (TR) at the cost of a modest increase in TR. To minimize TR, a noninterleaved phase-encode order in conjunction with a phased-array ghost elimination (PAGE) technique was employed, removing the need for echo time shifting (ETS). The multishot implementation of EPI-SSFP was used to decrease the breath-hold duration for cine acquisitions or to increase the temporal or spatial resolution for a fixed breath-hold duration. The greatest gain in efficiency was obtained with the use of a three-echo acquisition. Image quality for cardiac cine applications using multishot EPI-SSFP was comparable to that of single-echo SSFP in terms of blood-myocardium contrast and contrast-to-noise ratio (CNR). The PAGE method considerably reduced flow artifacts due to both the inherent ghost suppression and the concomitant reduction in phase-encode blip size. The increased TR of multishot EPI-SSFP led to a reduced specific absorption rate (SAR) for a fixed RF flip angle, and allowed the use of a larger flip angle without increasing the SAR above the FDA-approved limits. Copyright 2002 Wiley-Liss, Inc.

Relationship between clinical signs and pulmonary function estimated by the single breath diagram for CO(2) (SBD-CO(2)) in horses with chronic obstructive pulmonary disease.

PubMed

Herholz, C; Straub, R; Gerber, V; Wampfler, B; Lüthi, S; Imhof, A; Moens, Y; Busato, A

2002-03-01

The pulmonary health of 66 horses was assessed by a clinical examination and simple supplementary diagnostic methods. Single breath diagrams for CO(2) (SBD-CO(2)) and derived lung function indices were used to determine pulmonary function. The clinical signs in different groups were related to the results of the lung function indices derived from the SBD-CO(2). In horses with moderate to severe chronic obstructive pulmonary disease (COPD), a significant relationship was found between the respiratory frequency and the ratio of Bohr's dead space to the tidal volume (VD(Bohr)/VT), and between the physiological dead space/tidal volume ratio (VD(phys)/VT) and the ratio of the alveolar dead space to the alveolar tidal volume (VD(alv)/VT(alv)), but no significant associations were found between the arterial oxygen tension (P(a)O(2)) and lung function indices derived from the SBD-CO(2). The occurrence of cough, the viscosity of tracheobronchial mucus and the amount of polynuclear neutrophils in tracheobronchial aspirates were significantly related to the expiratory tidal volume (VT), the total expired volume of CO(2) (VCO(2)), VD(Bohr)/VT, VD(phys)/VT and VD(alv)/VT(alv). We conclude that abnormal findings in these clinical parameters indicate a measurable ventilation and perfusion (V(A)/Q) mismatch which is reflected by increases in dead space, VD(Bohr)/VT and VD(phys)/VT as well as VD(alv)/VT(alv). Copyright 2002 Elsevier Science Ltd. All rights reserved.

Diagnosis of acute respiratory distress syndrome by exhaled breath analysis

PubMed Central

2018-01-01

The acute respiratory distress syndrome (ARDS) is a complication of critical illness that is characterized by acute onset, protein rich, pulmonary edema. There is no treatment for ARDS, other than the reduction of additional ventilator induced lung injury. Prediction or earlier recognition of ARDS could result in preventive measurements and might decrease mortality and morbidity. Exhaled breath contains volatile organic compounds (VOCs), a collection of hundreds of small molecules linked to several physiological and pathophysiological processes. Analysis of exhaled breath through gas-chromatography and mass-spectrometry (GC-MS) has resulted in an accurate diagnosis of ARDS in several studies. Most identified markers are linked to lipid peroxidation. Octane is one of the few markers that was validated as a marker of ARDS and is pathophysiologically likely to be increased in ARDS. None of the currently studied breath analysis methods is directly applicable in clinical practice. Two steps have to be taken before any breath test can be allowed into the intensive care unit. External validation in a multi-center study is a prerequisite for any of the candidate breath markers and the breath test should outperform clinical prediction scores. Second, the technology for breath analysis should be adapted so that it is available at a decentralized lab inside the intensive care unit and can be operated by trained nurses, in order to reduce the analysis time. In conclusion, exhaled analysis might be used for the early diagnosis and prediction of ARDS in the near future but several obstacles have to be taken in the coming years. Most of the candidate markers can be linked to lipid peroxidation. Only octane has been validated in a temporal external validation cohort and is, at this moment, the top-ranking breath biomarker for ARDS. PMID:29430450

Unloading work of breathing during high-frequency oscillatory ventilation: a bench study

PubMed Central

van Heerde, Marc; Roubik, Karel; Kopelent, Vitek; Plötz, Frans B; Markhorst, Dick G

2006-01-01

Introduction With the 3100B high-frequency oscillatory ventilator (SensorMedics, Yorba Linda, CA, USA), patients' spontaneous breathing efforts result in a high level of imposed work of breathing (WOB). Therefore, spontaneous breathing often has to be suppressed during high-frequency oscillatory ventilation (HFOV). A demand-flow system was designed to reduce imposed WOB. Methods An external gas flow controller (demand-flow system) accommodates the ventilator fresh gas flow during spontaneous breathing simulation. A control algorithm detects breathing effort and regulates the demand-flow valve. The effectiveness of this system has been evaluated in a bench test. The Campbell diagram and pressure time product (PTP) are used to quantify the imposed workload. Results Using the demand-flow system, imposed WOB is considerably reduced. The demand-flow system reduces inspiratory imposed WOB by 30% to 56% and inspiratory imposed PTP by 38% to 59% compared to continuous fresh gas flow. Expiratory imposed WOB was decreased as well by 12% to 49%. In simulations of shallow to normal breathing for an adult, imposed WOB is 0.5 J l-1 at maximum. Fluctuations in mean airway pressure on account of spontaneous breathing are markedly reduced. Conclusion The use of the demand-flow system during HFOV results in a reduction of both imposed WOB and fluctuation in mean airway pressure. The level of imposed WOB was reduced to the physiological range of WOB. Potentially, this makes maintenance of spontaneous breathing during HFOV possible and easier in a clinical setting. Early initiation of HFOV seems more possible with this system and the possibility of weaning of patients directly on a high-frequency oscillatory ventilator is not excluded either. PMID:16848915

Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing

PubMed Central

2015-01-01

Background The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Methods Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. Results The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. Conclusion The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates. PMID:26192188

Exhaled breath profiling using broadband quantum cascade laser-based spectroscopy in healthy children and children with asthma and cystic fibrosis.

PubMed

van Mastrigt, E; Reyes-Reyes, A; Brand, K; Bhattacharya, N; Urbach, H P; Stubbs, A P; de Jongste, J C; Pijnenburg, M W

2016-04-08

Exhaled breath analysis is a potential non-invasive tool for diagnosing and monitoring airway diseases. Gas chromatography-mass spectrometry and electrochemical sensor arrays are the main techniques to detect volatile organic compounds (VOC) in exhaled breath. We developed a broadband quantum cascade laser spectroscopy technique for VOC detection and identification. The objective of this study was to assess the repeatability of exhaled breath profiling with broadband quantum cascade laser-based spectroscopy and to explore the clinical applicability by comparing exhaled breath samples from healthy children with those from children with asthma or cystic fibrosis (CF). Healthy children and children with stable asthma or stable CF, aged 6-18 years, were included. Two to four exhaled breath samples were collected in Tedlar bags and analyzed by quantum cascade laser spectroscopy to detect VOCs with an absorption profile in the wavenumber region between 832 and 1262.55 cm(-1). We included 35 healthy children, 39 children with asthma and 15 with CF. Exhaled breath VOC profiles showed poor repeatability (Spearman's rho  =  0.36 to 0.46) and agreement of the complete profiles. However, we were able to discriminate healthy children from children with stable asthma or stable CF and identified VOCs that were responsible for this discrimination. Broadband quantum cascade laser-based spectroscopy detected differences in VOC profiles in exhaled breath samples between healthy children and children with asthma or CF. The combination of a relatively easy and fast method and the possibility of molecule identification makes broadband quantum cascade laser-based spectroscopy attractive to investigate the diagnostic and prognostic potential of volatiles in exhaled breath.

SPECT Analysis of Cardiac Perfusion Changes After Whole-Breast/Chest Wall Radiation Therapy With or Without Active Breathing Coordinator: Results of a Randomized Phase 3 Trial

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zellars, Richard, E-mail: zellari@jhmi.edu; Bravo, Paco E.; Tryggestad, Erik

2014-03-15

Purpose: Cardiac muscle perfusion, as determined by single-photon emission computed tomography (SPECT), decreases after breast and/or chest wall (BCW) irradiation. The active breathing coordinator (ABC) enables radiation delivery when the BCW is farther from the heart, thereby decreasing cardiac exposure. We hypothesized that ABC would prevent radiation-induced cardiac toxicity and conducted a randomized controlled trial evaluating myocardial perfusion changes after radiation for left-sided breast cancer with or without ABC. Methods and Materials: Stages I to III left breast cancer patients requiring adjuvant radiation therapy (XRT) were randomized to ABC or No-ABC. Myocardial perfusion was evaluated by SPECT scans (before andmore » 6 months after BCW radiation) using 2 methods: (1) fully automated quantitative polar mapping; and (2) semiquantitative visual assessment. The left ventricle was divided into 20 segments for the polar map and 17 segments for the visual method. Segments were grouped by anatomical rings (apical, mid, basal) or by coronary artery distribution. For the visual method, 2 nuclear medicine physicians, blinded to treatment groups, scored each segment's perfusion. Scores were analyzed with nonparametric tests and linear regression. Results: Between 2006 and 2010, 57 patients were enrolled and 43 were available for analysis. The cohorts were well matched. The apical and left anterior descending coronary artery segments had significant decreases in perfusion on SPECT scans in both ABC and No-ABC cohorts. In unadjusted and adjusted analyses, controlling for pretreatment perfusion score, age, and chemotherapy, ABC was not significantly associated with prevention of perfusion deficits. Conclusions: In this randomized controlled trial, ABC does not appear to prevent radiation-induced cardiac perfusion deficits.« less

Nonstationary multivariate modeling of cerebral autoregulation during hypercapnia.

PubMed

Kostoglou, Kyriaki; Debert, Chantel T; Poulin, Marc J; Mitsis, Georgios D

2014-05-01

We examined the time-varying characteristics of cerebral autoregulation and hemodynamics during a step hypercapnic stimulus by using recursively estimated multivariate (two-input) models which quantify the dynamic effects of mean arterial blood pressure (ABP) and end-tidal CO2 tension (PETCO2) on middle cerebral artery blood flow velocity (CBFV). Beat-to-beat values of ABP and CBFV, as well as breath-to-breath values of PETCO2 during baseline and sustained euoxic hypercapnia were obtained in 8 female subjects. The multiple-input, single-output models used were based on the Laguerre expansion technique, and their parameters were updated using recursive least squares with multiple forgetting factors. The results reveal the presence of nonstationarities that confirm previously reported effects of hypercapnia on autoregulation, i.e. a decrease in the MABP phase lead, and suggest that the incorporation of PETCO2 as an additional model input yields less time-varying estimates of dynamic pressure autoregulation obtained from single-input (ABP-CBFV) models. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

The classification of the patients with pulmonary diseases using breath air samples spectral analysis

NASA Astrophysics Data System (ADS)

Kistenev, Yury V.; Borisov, Alexey V.; Kuzmin, Dmitry A.; Bulanova, Anna A.

2016-08-01

Technique of exhaled breath sampling is discussed. The procedure of wavelength auto-calibration is proposed and tested. Comparison of the experimental data with the model absorption spectra of 5% CO2 is conducted. The classification results of three study groups obtained by using support vector machine and principal component analysis methods are presented.

Impact of Typical Aging and Parkinson's Disease on the Relationship among Breath Pausing, Syntax, and Punctuation

ERIC Educational Resources Information Center

Huber, Jessica E.; Darling, Meghan; Francis, Elaine J.; Zhang, Dabao

2012-01-01

Purpose: The present study examines the impact of typical aging and Parkinson's disease (PD) on the relationship among breath pausing, syntax, and punctuation. Method: Thirty young adults, 25 typically aging older adults, and 15 individuals with PD participated. Fifteen participants were age- and sex-matched to the individuals with PD.…

Breath-based biomarkers for tuberculosis

NASA Astrophysics Data System (ADS)

Kolk, Arend H. J.; van Berkel, Joep J. B. N.; Claassens, Mareli M.; Walters, Elisabeth; Kuijper, Sjoukje; Dallinga, Jan W.; van Schooten, Fredrik-Jan

2012-06-01

We investigated the potential of breath analysis by gas chromatography - mass spectrometry (GC-MS) to discriminate between samples collected prospectively from patients with suspected tuberculosis (TB). Samples were obtained in a TB endemic setting in South Africa where 28% of the culture proven TB patients had a Ziehl-Neelsen (ZN) negative sputum smear. A training set of breath samples from 50 sputum culture proven TB patients and 50 culture negative non-TB patients was analyzed by GC-MS. A classification model with 7 compounds resulted in a training set with a sensitivity of 72%, specificity of 86% and accuracy of 79% compared with culture. The classification model was validated with an independent set of breath samples from 21 TB and 50 non-TB patients. A sensitivity of 62%, specificity of 84% and accuracy of 77% was found. We conclude that the 7 volatile organic compounds (VOCs) that discriminate breath samples from TB and non-TB patients in our study population are probably host-response related VOCs and are not derived from the VOCs secreted by M. tuberculosis. It is concluded that at present GC-MS breath analysis is able to differentiate between TB and non-TB breath samples even among patients with a negative ZN sputum smear but a positive culture for M. tuberculosis. Further research is required to improve the sensitivity and specificity before this method can be used in routine laboratories.

Detection of response to command using voluntary control of breathing in disorders of consciousness

PubMed Central

Charland-Verville, Vanessa; Lesenfants, Damien; Sela, Lee; Noirhomme, Quentin; Ziegler, Erik; Chatelle, Camille; Plotkin, Anton; Sobel, Noam; Laureys, Steven

2014-01-01

Background: Detecting signs of consciousness in patients in a vegetative state/unresponsive wakefulness syndrome (UWS/VS) or minimally conscious state (MCS) is known to be very challenging. Plotkin et al. (2010) recently showed the possibility of using a breathing-controlled communication device in patients with locked in syndrome. We here aim to test a breathing-based “sniff controller” that could be used as an alternative diagnostic tool to evaluate response to command in severely brain damaged patients with chronic disorders of consciousness (DOC). Methods: Twenty-five DOC patients were included. Patients’ resting breathing-amplitude was measured during a 5 min resting condition. Next, they were instructed to end the presentation of a music sequence by sniffing vigorously. An automated detection of changes in breathing amplitude (i.e., >1.5 SD of resting) ended the music and hence provided positive feedback to the patient. Results: None of the 11 UWS/VS patients showed a sniff-based response to command. One out of 14 patients with MCS was able to willfully modulate his breathing pattern to answer the command on 16/19 trials (accuracy 84%). Interestingly, this patient failed to show any other motor response to command. Discussion: We here illustrate the possible interest of using breathing-dependent response to command in the detection of residual cognition in patients with DOC after severe brain injury. PMID:25566035

A dosimetric study of cardiac dose sparing using the reverse semi-decubitus technique for left breast and internal mammary chain irradiation.

PubMed

Niglas, Mark; McCann, Claire; Keller, Brian M; Makhani, Nadiya; Presutti, Joseph; Vesprini, Danny; Rakovitch, Eileen; Elzibak, Alyaa; Mashouf, Shahram; Lee, Justin

2016-01-01

Breath-hold techniques can reduce cardiac dose in breast radiotherapy. The reverse semi-decubitus (RSD) technique is an alternative free-breathing method used at our centre. This study compares the dosimetry of free-breathing supine, RSD and moderate deep inspiration breath-hold (mDIBH) techniques. Twelve patients with left-sided breast cancer who were simulated using standard supine, RSD and mDIBH techniques were identified retrospectively. New plans using standard breast tangents and techniques for internal mammary chain (IMC) nodal coverage were assessed. Using standard tangents, mean heart dose, heart V25Gy and mean left anterior descending artery (LAD) dose were found to be significantly lower for RSD and mDIBH when compared to free-breathing supine (p ⩽ 0.03). Using wide-tangents, the maximum LAD point dose was also lower for RSD and mDIBH (p ⩽ 0.02). There were no statistically significant dosimetric differences found between the RSD and mDIBH simulation techniques for standard breast-tangent plans, though organ-at-risk doses were lower for mDIBH in wide-tangent plans. There was no improvement in cardiac dosimetry between RSD and free-breathing supine when using an electron field IMC plan. For patients unable to tolerate breath-hold, the RSD technique is an alternative approach that can reduce cardiac dose. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

SU-F-P-14: Oxygen Inhalation Should Be the Conventional Approach in the Treatment of Thoracic and Abdominal Cancer by Radiotherapy with Active Breathing Control (ABC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, G; Guo, Y; Yin, Y

Purpose: To investigate the feasibility and potential benefit of oxygen inhalation (OI) during radiotherapy applying an active breathing control (ABC) device, by analyzing the blood oxygen saturation (SpO2) and the instantaneous heart rate (IHR) variation in breath holding with OI and oxygen non-inhalation (ONI). Methods: The 27 healthy volunteers (16 males, 11 females) who were involved in this trial were all required to hold their breath for 10 times, non-inhaling and inhaling oxygen successively. The breath-holding time (BHT), rest time (RT), SpO2 and IHR under different oxygen status were recorded and compared. Results: The volunteers were divided into two groupsmore » according to SpO2 variations in breath-holding: group A (12 cases), with less than2% decline of SpO2; group B (15 cases), with a decline that surpassed 2%, and which could reach 3–6%. The BHT of group A, without inhaling oxygen, was significantly longer than that of group B (mean 33.77s Vs 30.51s, p<0.05); and was extended by 26.6% and 27.85%, after inhaling oxygen, in groups A and B, respectively. The SpO2 decreased in all volunteers during RT with ONI, to an extent that could reach up to 6%. The IHR of all volunteers showed the fast-slow-fast variation rule, and the oxygen had little effect. More than 70% of the volunteers stated that oxygen made them feel more comfortable and were more cooperative when ABC was used. Conclusion: The SpO2 declines during breath holding and RT could not be ignored while applying ABC, oxygen inhalation should become a conventional method with lengthening BHT and shortening RT, which yielded the benefit of improving the stability and reproducibility.« less

Portable method of measuring gaseous acetone concentrations.

PubMed

Worrall, Adam D; Bernstein, Jonathan A; Angelopoulos, Anastasios P

2013-08-15

Measurement of acetone in human breath samples has been previously shown to provide significant non-invasive diagnostic insight into the control of a patient's diabetic condition. In patients with diabetes mellitus, the body produces excess amounts of ketones such as acetone, which are then exhaled during respiration. Using various breath analysis methods has allowed for the accurate determination of acetone concentrations in exhaled breath. However, many of these methods require instrumentation and pre-concentration steps not suitable for point-of-care use. We have found that by immobilizing resorcinol reagent into a perfluorosulfonic acid polymer membrane, a controlled organic synthesis reaction occurs with acetone in a dry carrier gas. The immobilized, highly selective product of this reaction (a flavan) is found to produce a visible spectrum color change which could measure acetone concentrations to less than ppm. We here demonstrate how this approach can be used to produce a portable optical sensing device for real-time, non-invasive acetone analysis. Copyright © 2013 Elsevier B.V. All rights reserved.

3D tumor localization through real-time volumetric x-ray imaging for lung cancer radiotherapy.

PubMed

Li, Ruijiang; Lewis, John H; Jia, Xun; Gu, Xuejun; Folkerts, Michael; Men, Chunhua; Song, William Y; Jiang, Steve B

2011-05-01

To evaluate an algorithm for real-time 3D tumor localization from a single x-ray projection image for lung cancer radiotherapy. Recently, we have developed an algorithm for reconstructing volumetric images and extracting 3D tumor motion information from a single x-ray projection [Li et al., Med. Phys. 37, 2822-2826 (2010)]. We have demonstrated its feasibility using a digital respiratory phantom with regular breathing patterns. In this work, we present a detailed description and a comprehensive evaluation of the improved algorithm. The algorithm was improved by incorporating respiratory motion prediction. The accuracy and efficiency of using this algorithm for 3D tumor localization were then evaluated on (1) a digital respiratory phantom, (2) a physical respiratory phantom, and (3) five lung cancer patients. These evaluation cases include both regular and irregular breathing patterns that are different from the training dataset. For the digital respiratory phantom with regular and irregular breathing, the average 3D tumor localization error is less than 1 mm which does not seem to be affected by amplitude change, period change, or baseline shift. On an NVIDIA Tesla C1060 graphic processing unit (GPU) card, the average computation time for 3D tumor localization from each projection ranges between 0.19 and 0.26 s, for both regular and irregular breathing, which is about a 10% improvement over previously reported results. For the physical respiratory phantom, an average tumor localization error below 1 mm was achieved with an average computation time of 0.13 and 0.16 s on the same graphic processing unit (GPU) card, for regular and irregular breathing, respectively. For the five lung cancer patients, the average tumor localization error is below 2 mm in both the axial and tangential directions. The average computation time on the same GPU card ranges between 0.26 and 0.34 s. Through a comprehensive evaluation of our algorithm, we have established its accuracy in 3D tumor localization to be on the order of 1 mm on average and 2 mm at 95 percentile for both digital and physical phantoms, and within 2 mm on average and 4 mm at 95 percentile for lung cancer patients. The results also indicate that the accuracy is not affected by the breathing pattern, be it regular or irregular. High computational efficiency can be achieved on GPU, requiring 0.1-0.3 s for each x-ray projection.

Task-dependent output of human parasternal intercostal motor units across spinal levels.

PubMed

Hudson, Anna L; Gandevia, Simon C; Butler, Jane E

2017-12-01

During breathing, there is differential activity in the human parasternal intercostal muscles and the activity is tightly coupled to the known mechanical advantages for inspiration of the same regions of muscles. It is not known whether differential activity is preserved for the non-respiratory task of ipsilateral trunk rotation. In the present study, we compared single motor units during resting breathing and axial rotation of the trunk during apnoea. We not only confirmed non-uniform recruitment of motor units across parasternal intercostal muscles in breathing, but also demonstrated that the same motor units show an altered pattern of recruitment in the non-respiratory task of trunk rotation. The output of parasternal intercostal motoneurones is modulated differently across spinal levels depending on the task and these results help us understand the mechanisms that may govern task-dependent differences in motoneurone output. During inspiration, there is differential activity in the human parasternal intercostal muscles across interspaces. We investigated whether the earlier recruitment of motor units in the rostral interspaces compared to more caudal spaces during inspiration is preserved for the non-respiratory task of ipsilateral trunk rotation. Single motor unit activity (SMU) was recorded from the first, second and fourth parasternal interspaces on the right side in five participants in two tasks: resting breathing and 'isometric' axial rotation of the trunk during apnoea. Recruitment of the same SMUs was compared between tasks (n = 123). During resting breathing, differential activity was indicated by earlier recruitment of SMUs in the first and second interspaces compared to the fourth space in inspiration (P < 0.01). By contrast, during trunk rotation, the same motor units showed an altered pattern of recruitment because SMUs in the first interspace were recruited later and at a higher rotation torque than those in the second and fourth interspaces (P < 0.05). Tested for a subset of SMUs, the reliability of the breathing and rotation tasks, as well as the SMU recruitment measures, was good-excellent [intraclass correlation (2,1): 0.69-0.91]. Thus, the output of parasternal intercostal motoneurones is modulated differently across spinal levels depending on the task. Given that the differential inspiratory output of parasternal intercostal muscles is linked to their relative mechanical effectiveness for inspiration and also that this output is altered in trunk rotation, we speculate that a mechanism matching neural drive to muscle mechanics underlies the task-dependent differences in output of axial motoneurone pools. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

Effectiveness of different rescanning techniques for scanned proton radiotherapy in lung cancer patients

NASA Astrophysics Data System (ADS)

Engwall, E.; Glimelius, L.; Hynning, E.

2018-05-01

Non-small cell lung cancer (NSCLC) is a tumour type thought to be well-suited for proton radiotherapy. However, the lung region poses many problems related to organ motion and can for actively scanned beams induce severe interplay effects. In this study we investigate four mitigating rescanning techniques: (1) volumetric rescanning, (2) layered rescanning, (3) breath-sampled (BS) layered rescanning, and (4) continuous breath-sampled (CBS) layered rescanning. The breath-sampled methods will spread the layer rescans over a full breathing cycle, resulting in an improved averaging effect at the expense of longer treatment times. In CBS, we aim at further improving the averaging by delivering as many rescans as possible within one breathing cycle. The interplay effect was evaluated for 4D robustly optimized treatment plans (with and without rescanning) for seven NSCLC patients in the treatment planning system RayStation. The optimization and final dose calculation used a Monte Carlo dose engine to account for the density heterogeneities in the lung region. A realistic treatment delivery time structure given from the IBA ScanAlgo simulation tool served as basis for the interplay evaluation. Both slow (2.0 s) and fast (0.1 s) energy switching times were simulated. For all seven studied patients, rescanning improves the dose conformity to the target. The general trend is that the breath-sampled techniques are superior to layered and volumetric rescanning with respect to both target coverage and variability in dose to OARs. The spacing between rescans in our breath-sampled techniques is set at planning, based on the average breathing cycle length obtained in conjunction with CT acquisition. For moderately varied breathing cycle lengths between planning and delivery (up to 15%), the breath-sampled techniques still mitigate the interplay effect well. This shows the potential for smooth implementation at the clinic without additional motion monitoring equipment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conroy, L; Quirk, S; Smith, WL

Purpose: We used Real-Time Position Management (RPM) to evaluate breath hold amplitude and variability when gating with a visually monitored deep inspiration breath hold technique (VM-DIBH) with retrospective cine image chest wall position verification. Methods: Ten patients with left-sided breast cancer were treated using VM-DIBH. Respiratory motion was passively collected once weekly using RPM with the marker block positioned at the xiphoid process. Cine images on the tangent medial field were acquired on fractions with RPM monitoring for retrospective verification of chest wall position during breath hold. The amplitude and duration of all breath holds on which treatment beams weremore » delivered were extracted from the RPM traces. Breath hold position coverage was evaluated for symmetric RPM gating windows from ± 1 to 5 mm centered on the average breath hold amplitude of the first measured fraction as a baseline. Results: The average (range) breath hold amplitude and duration was 18 mm (3–36 mm) and 19 s (7–34 s). The average (range) of amplitude standard deviation per patient over all breath holds was 2.7 mm (1.2–5.7 mm). With the largest allowable RPM gating window (± 5 mm), 4 of 10 VM-DIBH patients would have had ≥ 10% of their breath hold positions excluded by RPM. Cine verification of the chest wall position during the medial tangent field showed that the chest wall was greater than 5 mm from the baseline in only 1 out of 4 excluded patients. Cine images verify the chest wall/breast position only, whether this variation is acceptable in terms of heart sparing is a subject of future investigation. Conclusion: VM-DIBH allows for greater breath hold amplitude variability than using a 5 mm gating window with RPM, while maintaining chest wall positioning accuracy within 5 mm for the majority of patients.« less

A Novel Fast Helical 4D-CT Acquisition Technique to Generate Low-Noise Sorting Artifact–Free Images at User-Selected Breathing Phases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, David, E-mail: dhthomas@mednet.ucla.edu; Lamb, James; White, Benjamin

2014-05-01

Purpose: To develop a novel 4-dimensional computed tomography (4D-CT) technique that exploits standard fast helical acquisition, a simultaneous breathing surrogate measurement, deformable image registration, and a breathing motion model to remove sorting artifacts. Methods and Materials: Ten patients were imaged under free-breathing conditions 25 successive times in alternating directions with a 64-slice CT scanner using a low-dose fast helical protocol. An abdominal bellows was used as a breathing surrogate. Deformable registration was used to register the first image (defined as the reference image) to the subsequent 24 segmented images. Voxel-specific motion model parameters were determined using a breathing motion model. Themore » tissue locations predicted by the motion model in the 25 images were compared against the deformably registered tissue locations, allowing a model prediction error to be evaluated. A low-noise image was created by averaging the 25 images deformed to the first image geometry, reducing statistical image noise by a factor of 5. The motion model was used to deform the low-noise reference image to any user-selected breathing phase. A voxel-specific correction was applied to correct the Hounsfield units for lung parenchyma density as a function of lung air filling. Results: Images produced using the model at user-selected breathing phases did not suffer from sorting artifacts common to conventional 4D-CT protocols. The mean prediction error across all patients between the breathing motion model predictions and the measured lung tissue positions was determined to be 1.19 ± 0.37 mm. Conclusions: The proposed technique can be used as a clinical 4D-CT technique. It is robust in the presence of irregular breathing and allows the entire imaging dose to contribute to the resulting image quality, providing sorting artifact–free images at a patient dose similar to or less than current 4D-CT techniques.« less

Wrist sensor for warfighter status monitor

NASA Astrophysics Data System (ADS)

Chen, Wuping

2000-04-01

There is a pressing need to improve human status monitoring in the medical and military communities. The heart rate and breading rate are the most important human vital signs. The current heart rate and breading rate monitors are rather cumbersome, expensive, and usually confined to the intensive care unit or ambulatory setting. These techniques are therefore unavailable to certain applications, such as home care and military applications. The purpose of this work is to develop new methods and new technologies for heart rate and breathing rate monitoring. To accomplish this task, a novel optical acoustic laser sensor (OALS) is characterized and used to generate an optical signal corresponding to human heart beat and breathing. An application specific integrated circuit (ASIC) is developed for this unique compact human status monitor Extensive experimental data analysis and simulation are conducted to investigate robust digital signal processing (DSP) methods. The Gauss-Hermite wavelet transform (GHWT) is utilized as a time-frequency representative technique to provide a method for the detection of the very low frequency heart rate and breathing rate from the large and noisy biomedical lasergram (BLG) signal. A 915MHz RF transceiver provides a reliable wireless link for the monitor to receive commands or transmit the measurement results to a remote commander center. A complete micro-instrument based on the ideas and methods above are developed and tested. The results show that the heart rate and breathing rate could be measured under difficult environmental situations.

Autocalibrating motion-corrected wave-encoding for highly accelerated free-breathing abdominal MRI.

PubMed

Chen, Feiyu; Zhang, Tao; Cheng, Joseph Y; Shi, Xinwei; Pauly, John M; Vasanawala, Shreyas S

2017-11-01

To develop a motion-robust wave-encoding technique for highly accelerated free-breathing abdominal MRI. A comprehensive 3D wave-encoding-based method was developed to enable fast free-breathing abdominal imaging: (a) auto-calibration for wave-encoding was designed to avoid extra scan for coil sensitivity measurement; (b) intrinsic butterfly navigators were used to track respiratory motion; (c) variable-density sampling was included to enable compressed sensing; (d) golden-angle radial-Cartesian hybrid view-ordering was incorporated to improve motion robustness; and (e) localized rigid motion correction was combined with parallel imaging compressed sensing reconstruction to reconstruct the highly accelerated wave-encoded datasets. The proposed method was tested on six subjects and image quality was compared with standard accelerated Cartesian acquisition both with and without respiratory triggering. Inverse gradient entropy and normalized gradient squared metrics were calculated, testing whether image quality was improved using paired t-tests. For respiratory-triggered scans, wave-encoding significantly reduced residual aliasing and blurring compared with standard Cartesian acquisition (metrics suggesting P < 0.05). For non-respiratory-triggered scans, the proposed method yielded significantly better motion correction compared with standard motion-corrected Cartesian acquisition (metrics suggesting P < 0.01). The proposed methods can reduce motion artifacts and improve overall image quality of highly accelerated free-breathing abdominal MRI. Magn Reson Med 78:1757-1766, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

The environmental effect on the radial breathing mode of carbon nanotubes in water

NASA Astrophysics Data System (ADS)

Longhurst, M. J.; Quirke, N.

2006-06-01

We investigate, using molecular dynamics, the effect on the radial breathing mode (RBM) frequency of immersion in water for a range of single-walled carbon nanotubes. We find that nanotube-water interactions are responsible for an upshift in the RBM frequency of the order of 4-10 wave numbers. The upshift is comprised of two components: increased hydrostatic pressure on the nanotube due to curvature effects, and the dynamic coupling of the RBM with its solvation shell. In contrast to much of the current literature, we find that the latter of the two effects is dominant. This could serve as an innovative tool for determining the interaction potential between nanotubes/graphitic surfaces and fluids.

A real-time respiration position based passive breath gating equipment for gated radiotherapy: A preclinical evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu Weigang; Xu Anjie; Li Guichao

2012-03-15

Purpose: To develop a passive gating system incorporating with the real-time position management (RPM) system for the gated radiotherapy. Methods: Passive breath gating (PBG) equipment, which consists of a breath-hold valve, a controller mechanism, a mouthpiece kit, and a supporting frame, was designed. A commercial real-time positioning management system was implemented to synchronize the target motion and radiation delivery on a linear accelerator with the patient's breathing cycle. The respiratory related target motion was investigated by using the RPM system for correlating the external markers with the internal target motion while using PBG for passively blocking patient's breathing. Six patientsmore » were enrolled in the preclinical feasibility and efficiency study of the PBG system. Results: PBG equipment was designed and fabricated. The PBG can be manually triggered or released to block or unblock patient's breathing. A clinical workflow was outlined to integrate the PBG with the RPM system. After implementing the RPM based PBG system, the breath-hold period can be prolonged to 15-25 s and the treatment delivery efficiency for each field can be improved by 200%-400%. The results from the six patients showed that the diaphragm motion caused by respiration was reduced to less than 3 mm and the position of the diaphragm was reproducible for difference gating periods. Conclusions: A RPM based PBG system was developed and implemented. With the new gating system, the patient's breath-hold time can be extended and a significant improvement in the treatment delivery efficiency can also be achieved.« less

The Effect of Breathing Exercises on the Nocturnal Enuresis in the Children with the Sleep-Disordered Breathing

PubMed Central

Khaleghipour, Shahnaz; Masjedi, Mohsen; Kelishadi, Roya

2013-01-01

Background The nocturnal enuresis is one of the most common complaints of childhood. Upper airway obstruction and nocturnal snoring affect the nocturnal enuresis in children. Objectives The aim of this study was to investigate the effects of breathing exercises on the nocturnal enuresis in the children with the sleep-disordered breathing. Patients and Methods This study was conducted in year of 2011 by a semi-experimental design with the control group among 40 children, aged 6 - 12 years, who had the nocturnal enuresis. Participants were examined based on the criteria of nocturnal enuresis, oral breathing, and nocturnal snoring. Subsequently, they were randomly assigned to the case and control groups. In the case group, the breathing exercises were performed for 45 minutes, and were pursued for four weeks in the morning following and prior to sleeping, and subsequently the arterial blood gases were measured and the frequency of enuresis and the respiratory rates (RR) were recorded. Results After intervention the means of PaCO2 and RR in the control group were significantly higher than the case group (P < 0.0001). Likewise, O2sat, PaO2 in the case group were higher than the control group (P < 0.0001). The nocturnal enuresis decreased significantly in the case group, compared to the control group (P < 0.0001). Conclusions This study suggests that the breathing exercises may reduce the frequency of nocturnal enuresis in the patients with the oral breathing and nocturnal snore. The clinical implications of these findings should be verified in the future longitudinal studies. PMID:24719691

Drug detection in breath: non-invasive assessment of illicit or pharmaceutical drugs.

PubMed

Trefz, Phillip; Kamysek, Svend; Fuchs, Patricia; Sukul, Pritam; Schubert, Jochen K; Miekisch, Wolfram

2017-03-20

Breath analysis not only holds great potential for the development of new non-invasive diagnostic methods, but also for the identification and follow up of drug levels in breath. This is of interest for both, forensic and medical science. On the one hand, the detection of drugs of abuse in exhaled breath-similar to the well-known breath alcohol tests-would be highly desirable as an alternative to blood or urine analysis in situations such as police controls for drugged driving. The non-invasive detection of drugs and their metabolites is thus of great interest in forensic science, especially since marijuana is becoming legalized in certain parts of the US and the EU. The detection and monitoring of medical drugs in exhaled breath without the need of drawing blood samples on the other hand, is of high relevance in the clinical environment. This could facilitate a more precise medication and enable therapy control without any burden to the patient. Furthermore, it could be a step towards personalized medicine. This review gives an overview of the current state of drug detection in breath, including both volatile and non-volatile substances. The review is divided into two sections. The first section deals with qualitative detection of drugs (drugs of abuse), while the second is related to quantitative drug detection (medical drugs). Chances and limitations are discussed for both aspects. The detection of the intravenous anesthetic propofol is presented as a detailed example that demonstrates the potential, requirements, pitfalls and limitations of therapeutic drug monitoring by means of breath analysis.

Postural disorders in mouth breathing children: a systematic review.

PubMed

Neiva, Patricia Dayrell; Kirkwood, Renata Noce; Mendes, Polyana Leite; Zabjek, Karl; Becker, Helena Gonçalves; Mathur, Sunita

Mouth breathing syndrome can cause sleep disturbances that compromise the performance of children in school. It might also cause postural abnormalities involving the head and cervical spine; however, the association between postural abnormalities and mouth breathing in children is unclear. To assess the methodological quality of studies and determine if there is an association between mouth breathing and postural disorders in children. Databases comprised MEDLINE, CINAHL, PEDro, LILACS, EMBASE and Cochrane Central Registrar of Controlled Trials. Searches were until March 2016 and included studies that evaluated postural disorders in children diagnosed with mouth breathing. The Downs and Black checklist was used to evaluate the quality of the evidences. Ten studies were included totaling 417 children from 5 to 14 years. Two studies used the New York State Postural Rating Scale, seven used photography and one used motion capture to measure posture. The methods used to analyze the data included the Postural Analysis Software (SAPO), Fisiometer, ALCimagem and routines in MATLAB program. Quality assessment resulted in low scores (<14) for all the studies. The main areas of weakness were a clear description of the participants, of the methods used to access posture, of the principal confounders and lack of power analysis. External and internal validity were also threatened by the lack of a representative sample and blinding of the participants and assessors, respectively. The review provides low evidence that mouth-breathing pattern in children between the ages 5-14 years is associated with postural deviations. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

Evaluation of a new method for the collection and measurement of 8-isoprostane in exhaled breath for future application in nanoparticle exposure biomonitoring.

PubMed

Marie-Desvergne, Caroline; Dubosson, Muriel; Mossuz, Véronique Chamel

2018-05-14

In the field of nanoparticle exposure biomonitoring, oxidative stress biomarkers measured in exhaled breath condensate appear promising to detect early respiratory effects in workers handling nanomaterials. However, condensation is known for its poor efficiency in collecting non-volatiles in exhaled breath, leading to the low sensitivity of such measurements. Moreover, to be easily used in field studies on large groups of workers, the collection device must be disposable and convenient. In this study, we have tested a totally disposable commercial device that allows for the easy dry collection of exhaled air after filtration on a patented filter. The suitability and efficiency of the SensAbues (SB) device for collecting 8-isoprostane were evaluated and compared to the RTube (RT). Seven healthy volunteers performed two 15 min collections of exhaled breath, one with the SB and one with the RT. Blank devices were used to determine the background levels induced by each device. 8-isoprostane was measured in all samples using an EIA technique. The levels of 8-isoprostane in the exhaled breath of volunteers after collection with the SB were significantly higher than those after collection with the RT. Moreover, the levels obtained in volunteers with the SB were significantly higher than background levels obtained in blank devices, which was not the case for the RT. This is the first study to report the ability of the SB device to collect and measure 8-isoprostane in exhaled breath. The proposed method offers better sensitivity than a classical collection with the RT device and should be further explored before future application in biomonitoring studies.

Analysis of single-breath profiles of exhaled nitric oxide in children with allergy and asthma: guideline-derived plateau concentrations compared to results of automatic evaluation by two analyzers.

PubMed

Chládková, Jirina; Havlínová, Zuzana; Chyba, Tomás; Krcmová, Irena; Chládek, Jaroslav

2008-11-01

Current guidelines recommend the single-breath measurement of fractional concentration of exhaled nitric oxide (FE(NO)) at the expiratory flow rate of 50 mL/s as a gold standard. The time profile of exhaled FE(NO) consists of a washout phase followed by a plateau phase with a stable concentration. This study performed measurements of FE(NO) using a chemiluminescence analyzer Ecomedics CLD88sp and an electrochemical monitor NIOX MINO in 82 children and adolescents (44 males) from 4.9 to 18.7 years of age with corticosteroid-treated allergic rhinitis (N = 58) and/or asthma (N = 59). Duration of exhalation was 6 seconds for children less than 12 years of age and 10 seconds for older children. The first aim was to compare the evaluation of FE(NO)-time profiles from Ecomedics by its software in fixed intervals of 7 to 10 seconds (older children) and 2 to 4 seconds (younger children) since the start of exhalation (method A) with the guideline-based analysis of plateau concentrations at variable time intervals (method B). The second aim was to assess the between-analyzer agreement. In children over 12 years of age, the median ratio of FE(NO) concentrations of 1.00 (95% CI: 0.99-1.02) indicated an excellent agreement between the methods A and B. Compared with NIOX MINO, the Ecomedics results were higher by 11% (95% CI: 1-22) (method A) and 14% (95% CI: 4-26) (method B), respectively. In children less than 12 years of age, the FE(NO) concentrations obtained by the method B were 34% (95% CI: 21-48) higher and more reproducible (p < 0.02) compared to the method A. The Ecomedics results of the method A were 11% lower (95% CI: 2-20) than NIOX MINO concentrations while the method B gave 21% higher concentrations (95% CI: 9-35). We conclude that in children less than 12 years of age, the guideline-based analysis of FE(NO)-time profiles from Ecomedics at variable times obtains FE(NO) concentrations that are higher and more reproducible than those from the fixed interval of 2 to 4 seconds and higher than NIOX MINO concentrations obtained during a short exhalation (6 seconds). The Ecomedics FE(NO) concentrations of children more than 12 years of age calculated in the interval of 7 to 10 seconds represent plateau values and agree well with NIOX MINO results obtained during a standard 10-second exhalation.

Computerized method to compensate for breathing body motion in dynamic chest radiographs

NASA Astrophysics Data System (ADS)

Matsuda, H.; Tanaka, R.; Sanada, S.

2017-03-01

Dynamic chest radiography combined with computer analysis allows quantitative analyses on pulmonary function and rib motion. The accuracy of kinematic analysis is directly linked to diagnostic accuracy, and thus body motion compensation is a major concern. Our purpose in this study was to develop a computerized method to reduce a breathing body motion in dynamic chest radiographs. Dynamic chest radiographs of 56 patients were obtained using a dynamic flat-panel detector. The images were divided into a 1 cm-square and the squares on body counter were used to detect the body motion. Velocity vector was measured using cross-correlation method on the body counter and the body motion was then determined on the basis of the summation of motion vector. The body motion was then compensated by shifting the images based on the measured vector. By using our method, the body motion was accurately detected by the order of a few pixels in clinical cases, mean 82.5% in right and left directions. In addition, our method detected slight body motion which was not able to be identified by human observations. We confirmed our method effectively worked in kinetic analysis of rib motion. The present method would be useful for the reduction of a breathing body motion in dynamic chest radiography.

SU-E-J-191: Motion Prediction Using Extreme Learning Machine in Image Guided Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, J; Cao, R; Pei, X

Purpose: Real-time motion tracking is a critical issue in image guided radiotherapy due to the time latency caused by image processing and system response. It is of great necessity to fast and accurately predict the future position of the respiratory motion and the tumor location. Methods: The prediction of respiratory position was done based on the positioning and tracking module in ARTS-IGRT system which was developed by FDS Team (www.fds.org.cn). An approach involving with the extreme learning machine (ELM) was adopted to predict the future respiratory position as well as the tumor’s location by training the past trajectories. For themore » training process, a feed-forward neural network with one single hidden layer was used for the learning. First, the number of hidden nodes was figured out for the single layered feed forward network (SLFN). Then the input weights and hidden layer biases of the SLFN were randomly assigned to calculate the hidden neuron output matrix. Finally, the predicted movement were obtained by applying the output weights and compared with the actual movement. Breathing movement acquired from the external infrared markers was used to test the prediction accuracy. And the implanted marker movement for the prostate cancer was used to test the implementation of the tumor motion prediction. Results: The accuracy of the predicted motion and the actual motion was tested. Five volunteers with different breathing patterns were tested. The average prediction time was 0.281s. And the standard deviation of prediction accuracy was 0.002 for the respiratory motion and 0.001 for the tumor motion. Conclusion: The extreme learning machine method can provide an accurate and fast prediction of the respiratory motion and the tumor location and therefore can meet the requirements of real-time tumor-tracking in image guided radiotherapy.« less

The respiratory system under weightlessness

NASA Technical Reports Server (NTRS)

Paiva, M.; Engel, L. A.; Hughes, J. M. B.; Guy, H. J.; Prisk, G. K.; West, J. B.

1987-01-01

Studies of pulmonary functions at rest to be studied on Spacelab mission D-2 are introduced. Gravity dependence of the distribution of ventilation (single breath washout, multibreath washout-washin); chest wall shape and motion; and the vascular compartment (lung blood flow, capillary volume, liquid content, diffusive capacity) are discussed.

Blinded Validation of Breath Biomarkers of Lung Cancer, a Potential Ancillary to Chest CT Screening

PubMed Central

Phillips, Michael; Bauer, Thomas L.; Cataneo, Renee N.; Lebauer, Cassie; Mundada, Mayur; Pass, Harvey I.; Ramakrishna, Naren; Rom, William N.; Vallières, Eric

2015-01-01

Background Breath volatile organic compounds (VOCs) have been reported as biomarkers of lung cancer, but it is not known if biomarkers identified in one group can identify disease in a separate independent cohort. Also, it is not known if combining breath biomarkers with chest CT has the potential to improve the sensitivity and specificity of lung cancer screening. Methods Model-building phase (unblinded): Breath VOCs were analyzed with gas chromatography mass spectrometry in 82 asymptomatic smokers having screening chest CT, 84 symptomatic high-risk subjects with a tissue diagnosis, 100 without a tissue diagnosis, and 35 healthy subjects. Multiple Monte Carlo simulations identified breath VOC mass ions with greater than random diagnostic accuracy for lung cancer, and these were combined in a multivariate predictive algorithm. Model-testing phase (blinded validation): We analyzed breath VOCs in an independent cohort of similar subjects (n = 70, 51, 75 and 19 respectively). The algorithm predicted discriminant function (DF) values in blinded replicate breath VOC samples analyzed independently at two laboratories (A and B). Outcome modeling: We modeled the expected effects of combining breath biomarkers with chest CT on the sensitivity and specificity of lung cancer screening. Results Unblinded model-building phase. The algorithm identified lung cancer with sensitivity 74.0%, specificity 70.7% and C-statistic 0.78. Blinded model-testing phase: The algorithm identified lung cancer at Laboratory A with sensitivity 68.0%, specificity 68.4%, C-statistic 0.71; and at Laboratory B with sensitivity 70.1%, specificity 68.0%, C-statistic 0.70, with linear correlation between replicates (r = 0.88). In a projected outcome model, breath biomarkers increased the sensitivity, specificity, and positive and negative predictive values of chest CT for lung cancer when the tests were combined in series or parallel. Conclusions Breath VOC mass ion biomarkers identified lung cancer in a separate independent cohort, in a blinded replicated study. Combining breath biomarkers with chest CT could potentially improve the sensitivity and specificity of lung cancer screening. Trial Registration ClinicalTrials.gov NCT00639067 PMID:26698306

Sleep-Disordered Breathing and Mortality: A Prospective Cohort Study

PubMed Central

Punjabi, Naresh M.; Caffo, Brian S.; Goodwin, James L.; Gottlieb, Daniel J.; Newman, Anne B.; O'Connor, George T.; Rapoport, David M.; Redline, Susan; Resnick, Helaine E.; Robbins, John A.; Shahar, Eyal; Unruh, Mark L.; Samet, Jonathan M.

2009-01-01

Background Sleep-disordered breathing is a common condition associated with adverse health outcomes including hypertension and cardiovascular disease. The overall objective of this study was to determine whether sleep-disordered breathing and its sequelae of intermittent hypoxemia and recurrent arousals are associated with mortality in a community sample of adults aged 40 years or older. Methods and Findings We prospectively examined whether sleep-disordered breathing was associated with an increased risk of death from any cause in 6,441 men and women participating in the Sleep Heart Health Study. Sleep-disordered breathing was assessed with the apnea–hypopnea index (AHI) based on an in-home polysomnogram. Survival analysis and proportional hazards regression models were used to calculate hazard ratios for mortality after adjusting for age, sex, race, smoking status, body mass index, and prevalent medical conditions. The average follow-up period for the cohort was 8.2 y during which 1,047 participants (587 men and 460 women) died. Compared to those without sleep-disordered breathing (AHI: <5 events/h), the fully adjusted hazard ratios for all-cause mortality in those with mild (AHI: 5.0–14.9 events/h), moderate (AHI: 15.0–29.9 events/h), and severe (AHI: ≥30.0 events/h) sleep-disordered breathing were 0.93 (95% CI: 0.80–1.08), 1.17 (95% CI: 0.97–1.42), and 1.46 (95% CI: 1.14–1.86), respectively. Stratified analyses by sex and age showed that the increased risk of death associated with severe sleep-disordered breathing was statistically significant in men aged 40–70 y (hazard ratio: 2.09; 95% CI: 1.31–3.33). Measures of sleep-related intermittent hypoxemia, but not sleep fragmentation, were independently associated with all-cause mortality. Coronary artery disease–related mortality associated with sleep-disordered breathing showed a pattern of association similar to all-cause mortality. Conclusions Sleep-disordered breathing is associated with all-cause mortality and specifically that due to coronary artery disease, particularly in men aged 40–70 y with severe sleep-disordered breathing. Please see later in the article for the Editors' Summary PMID:19688045

Fructose and lactose intolerance and malabsorption testing: the relationship with symptoms in functional gastrointestinal disorders

PubMed Central

Wilder-Smith, C H; Materna, A; Wermelinger, C; Schuler, J

2013-01-01

Background The association of fructose and lactose intolerance and malabsorption with the symptoms of different functional gastrointestinal disorders (FGID) remains unclear. Aim To investigate the prevalence of fructose and lactose intolerance (symptom induction) and malabsorption and their association with clinical gastrointestinal (GI) as well as non-GI symptoms in FGID and the outcome of dietary intervention. Methods Fructose and lactose intolerance (defined by positive symptom index) and malabsorption (defined by increased hydrogen/methane) were determined in 1372 FGID patients in a single centre using breath testing. Results were correlated with clinical symptoms in different FGID Rome III subgroups. The effectiveness of a targeted saccharide-reduced diet was assessed after 6–8 weeks. Results Intolerance prevalence across all FGIDs was 60% to fructose, 51% to lactose and 33% to both. Malabsorption occurred in 45%, 32% and 16% respectively. There were no differences in intolerance or malabsorption prevalence between FGID subgroups. FGID symptoms correlated with symptoms evoked during testing (r = 0.35–0.61. P < 0.0001), but not with malabsorption. Non-GI symptoms occurred more commonly in patients with intolerances. Methane breath levels were not associated with constipation using several cut-off thresholds. Adequate symptom relief was achieved in >80% of intolerant patients, irrespective of malabsorption. Conclusions Fructose and lactose intolerances are common in FGID and associated with increased non-GI symptoms, but not with specific FGID subtypes. Symptoms experienced during breath testing, but not malabsorption, correlate with FGID symptoms. Effective symptom relief with dietary adaptation is not associated with malabsorption. Mechanisms relating to the generation of GI and non-GI symptoms due to lactose and fructose in FGID need to be explored further. PMID:23574302

Exploring Structural Relationships Between Blood Alcohol Concentration and Signs and Clinical Assessment of Intoxication in Alcohol-Involved Injury Cases

PubMed Central

Bond, Jason; Witbrodt, Jane; Ye, Yu; Cherpitel, Cheryl J.; Room, Robin; Monteiro, Maristela G.

2014-01-01

Aims: Although the relationship between the Y90 (blood alcohol concentration, BAC) and Y91 (clinician intoxication assessment) ICD-10 codes has received attention recently, the role of 10 signs of intoxication in the Y91–Y90 relationship has not been studied yet. This work examines these signs in the estimation of alcohol intoxication levels of patients in medical settings. Methods: Collected and analyzed were data on 1997 injured emergency room patients from 17 countries worldwide reporting drinking prior to injury or presenting with a non-zero BAC from 17 countries worldwide. A model is estimated describing how the 10 signs inform the Y91, Y90 prediction with the goal of the use of observations on patients in place of a biological measure. Results: Signs were consistent with a single underlying construct that strongly predicted Y91. Smell of alcohol on breath predicted Y91 above its contribution through the construct and was stronger for those with tolerance to alcohol than for those without. Controlling for Y91, no sign further contributed to prediction of Y90 indicating that Y91 incorporated all intoxication sign information in predicting Y90. Variance explained was high for Y91 (R2 = 0.84) and intoxication signs (above 0.72 for all but smell on the breath, 0.57) and lower for Y90 (0.38). Conclusion: Intoxication assessments are well predicted by overall intoxication severity, which itself is well represented by intoxication signs along with differential emphasis on smell of alcohol on breath, especially for those with alcohol tolerance. However, BAC levels remain largely unexplained by intoxication signs with a clinician's assessment serving as the primary predictive measure. PMID:24705784

Accelerated dynamic cardiac MRI exploiting sparse-Kalman-smoother self-calibration and reconstruction (k  -  t SPARKS)

NASA Astrophysics Data System (ADS)

Park, Suhyung; Park, Jaeseok

2015-05-01

Accelerated dynamic MRI, which exploits spatiotemporal redundancies in k  -  t space and coil dimension, has been widely used to reduce the number of signal encoding and thus increase imaging efficiency with minimal loss of image quality. Nonetheless, particularly in cardiac MRI it still suffers from artifacts and amplified noise in the presence of time-drifting coil sensitivity due to relative motion between coil and subject (e.g. free breathing). Furthermore, a substantial number of additional calibrating signals is to be acquired to warrant accurate calibration of coil sensitivity. In this work, we propose a novel, accelerated dynamic cardiac MRI with sparse-Kalman-smoother self-calibration and reconstruction (k  -  t SPARKS), which is robust to time-varying coil sensitivity even with a small number of calibrating signals. The proposed k  -  t SPARKS incorporates Kalman-smoother self-calibration in k  -  t space and sparse signal recovery in x  -   f space into a single optimization problem, leading to iterative, joint estimation of time-varying convolution kernels and missing signals in k  -  t space. In the Kalman-smoother calibration, motion-induced uncertainties over the entire time frames were included in modeling state transition while a coil-dependent noise statistic in describing measurement process. The sparse signal recovery iteratively alternates with the self-calibration to tackle the ill-conditioning problem potentially resulting from insufficient calibrating signals. Simulations and experiments were performed using both the proposed and conventional methods for comparison, revealing that the proposed k  -  t SPARKS yields higher signal-to-error ratio and superior temporal fidelity in both breath-hold and free-breathing cardiac applications over all reduction factors.

Advanced treatment planning using direct 4D optimisation for pencil-beam scanned particle therapy

NASA Astrophysics Data System (ADS)

Bernatowicz, Kinga; Zhang, Ye; Perrin, Rosalind; Weber, Damien C.; Lomax, Antony J.

2017-08-01

We report on development of a new four-dimensional (4D) optimisation approach for scanned proton beams, which incorporates both irregular motion patterns and the delivery dynamics of the treatment machine into the plan optimiser. Furthermore, we assess the effectiveness of this technique to reduce dose to critical structures in proximity to moving targets, while maintaining effective target dose homogeneity and coverage. The proposed approach has been tested using both a simulated phantom and a clinical liver cancer case, and allows for realistic 4D calculations and optimisation using irregular breathing patterns extracted from e.g. 4DCT-MRI (4D computed tomography-magnetic resonance imaging). 4D dose distributions resulting from our 4D optimisation can achieve almost the same quality as static plans, independent of the studied geometry/anatomy or selected motion (regular and irregular). Additionally, current implementation of the 4D optimisation approach requires less than 3 min to find the solution for a single field planned on 4DCT of a liver cancer patient. Although 4D optimisation allows for realistic calculations using irregular breathing patterns, it is very sensitive to variations from the planned motion. Based on a sensitivity analysis, target dose homogeneity comparable to static plans (D5-D95  <5%) has been found only for differences in amplitude of up to 1 mm, for changes in respiratory phase  <200 ms and for changes in the breathing period of  <20 ms in comparison to the motions used during optimisation. As such, methods to robustly deliver 4D optimised plans employing 4D intensity-modulated delivery are discussed.

Accelerated dynamic cardiac MRI exploiting sparse-Kalman-smoother self-calibration and reconstruction (k  -  t SPARKS).

PubMed

Park, Suhyung; Park, Jaeseok

2015-05-07

Accelerated dynamic MRI, which exploits spatiotemporal redundancies in k  -  t space and coil dimension, has been widely used to reduce the number of signal encoding and thus increase imaging efficiency with minimal loss of image quality. Nonetheless, particularly in cardiac MRI it still suffers from artifacts and amplified noise in the presence of time-drifting coil sensitivity due to relative motion between coil and subject (e.g. free breathing). Furthermore, a substantial number of additional calibrating signals is to be acquired to warrant accurate calibration of coil sensitivity. In this work, we propose a novel, accelerated dynamic cardiac MRI with sparse-Kalman-smoother self-calibration and reconstruction (k  -  t SPARKS), which is robust to time-varying coil sensitivity even with a small number of calibrating signals. The proposed k  -  t SPARKS incorporates Kalman-smoother self-calibration in k  -  t space and sparse signal recovery in x  -   f space into a single optimization problem, leading to iterative, joint estimation of time-varying convolution kernels and missing signals in k  -  t space. In the Kalman-smoother calibration, motion-induced uncertainties over the entire time frames were included in modeling state transition while a coil-dependent noise statistic in describing measurement process. The sparse signal recovery iteratively alternates with the self-calibration to tackle the ill-conditioning problem potentially resulting from insufficient calibrating signals. Simulations and experiments were performed using both the proposed and conventional methods for comparison, revealing that the proposed k  -  t SPARKS yields higher signal-to-error ratio and superior temporal fidelity in both breath-hold and free-breathing cardiac applications over all reduction factors.

Effect Of Pressure Support Versus Unassisted Breathing Through A Tracheostomy Collar On Weaning Duration In Patients Requiring Prolonged Mechanical Ventilation: A Randomized Trial

PubMed Central

Jubran, Amal; Grant, Brydon J.B.; Duffner, Lisa A.; Collins, Eileen G.; Lanuza, Dorothy M.; Hoffman, Leslie A.; Tobin, Martin J.

2013-01-01

Context Patients requiring prolonged mechanical ventilation (more than 21 days) are commonly weaned at long-term acute care hospitals (LTACHs). The most effective method of weaning such patients has not been investigated. Objective To compare weaning duration with pressure support versus unassisted breathing through a tracheostomy (trach collar) in patients transferred to a LTACH for weaning from prolonged ventilation. Design, Settings, and Participants Between 2000 and 2010, a randomized study was conducted in tracheotomized patients transferred to a single LTACH for weaning from prolonged ventilation. Of 500 patients who underwent a five-day screening procedure, 316 failed and were randomly assigned to wean with pressure support (n=155) or a trach collar (n=161). Six- and twelve-month survival was also determined. Main outcome measure Primary outcome was weaning duration. Secondary outcome was survival at six and twelve months after enrollment. Results Of 316 patients, four were withdrawn and not included in analysis. Of 152 patients in the pressure-support arm, 68 (44.7%) were weaned; 22 (14.5%) died. Of 160 patients in the trach-collar arm, 85 (53.1%) were weaned; 16 (10.0%) died. Median weaning time was shorter with trach collar than with pressure support: 15 [interquartile range, 8–25] versus 19 [12–31] days, p=0.004. The hazard ratio (HR) for successful weaning rate was higher with trach collar than with pressure support (HR, 1.43; 95% confidence interval [CI], 1.03–1.98, p<0.03) after adjusting for baseline clinical covariates. Trach collar achieved faster weaning than did pressure support among subjects who failed the screening procedure at 12–120 hours (HR, 3.33; 95% CI, 1.44–7.70, p<0.01), whereas weaning time was equivalent with the two methods in patients who failed the screening procedure within 0–12 hours. Mortality was equivalent in the pressure-support and trach-collar arms at six months (55.9% versus 51.3%; 4.7 difference, 95% CI −6.4 to 15.7%) and twelve months (66.4% versus 60.0%; 6.5 difference, 95% CI −4.2 to 17.1 %). Conclusion Among patients requiring prolonged mechanical ventilation and treated at a single long-term care facility, unassisted breathing through a tracheostomy, compared with pressure support, resulted in shorter median weaning time, although weaning mode had no effect on survival at 6 and 12 months. PMID:23340588

Effect of pressure support vs unassisted breathing through a tracheostomy collar on weaning duration in patients requiring prolonged mechanical ventilation: a randomized trial.

PubMed

Jubran, Amal; Grant, Brydon J B; Duffner, Lisa A; Collins, Eileen G; Lanuza, Dorothy M; Hoffman, Leslie A; Tobin, Martin J

2013-02-20

Patients requiring prolonged mechanical ventilation (>21 days) are commonly weaned at long-term acute care hospitals (LTACHs). The most effective method of weaning such patients has not been investigated. To compare weaning duration with pressure support vs unassisted breathing through a tracheostomy collar in patients transferred to an LTACH for weaning from prolonged ventilation. Between 2000 and 2010, a randomized study was conducted in tracheotomized patients transferred to a single LTACH for weaning from prolonged ventilation. Of 500 patients who underwent a 5-day screening procedure, 316 did not tolerate the procedure and were randomly assigned to receive weaning with pressure support (n = 155) or a tracheostomy collar (n = 161). Survival at 6- and 12-month time points was also determined. Primary outcome was weaning duration. Secondary outcome was survival at 6 and 12 months after enrollment. Of 316 patients, 4 were withdrawn and not included in analysis. Of 152 patients in the pressure-support group, 68 (44.7%) were weaned; 22 (14.5%) died. Of 160 patients in the tracheostomy collar group, 85 (53.1%) were weaned; 16 (10.0%) died. Median weaning time was shorter with tracheostomy collar use (15 days; interquartile range [IQR], 8-25) than with pressure support (19 days; IQR, 12-31), P = .004. The hazard ratio (HR) for successful weaning rate was higher with tracheostomy collar use than with pressure support (HR, 1.43; 95% CI, 1.03-1.98; P = .033) after adjusting for baseline clinical covariates. Use of the tracheostomy collar achieved faster weaning than did pressure support among patients who did not tolerate the screening procedure between 12 and 120 hours (HR, 3.33; 95% CI, 1.44-7.70; P = .005), whereas weaning time was equivalent with the 2 methods in patients who did not tolerate the screening procedure within 0 to 12 hours. Mortality was equivalent in the pressure-support and tracheostomy collar groups at 6 months (55.92% vs 51.25%; 4.67% difference, 95% CI, -6.4% to 15.7%) and at 12 months (66.45% vs 60.00%; 6.45% difference, 95% CI, -4.2% to 17.1%). Among patients requiring prolonged mechanical ventilation and treated at a single long-term care facility, unassisted breathing through a tracheostomy, compared with pressure support, resulted in shorter median weaning time, although weaning mode had no effect on survival at 6 and 12 months. clinicaltrials.gov Identifier: NCT01541462.

Adults with ADHD and Sleep Complaints: A Pilot Study Identifying Sleep-Disordered Breathing Using Polysomnography and Sleep Quality Assessment

ERIC Educational Resources Information Center

Surman, Craig B. H.; Thomas, Robert J.; Aleardi, Megan; Pagano, Christine; Biederman, Joseph

2006-01-01

Objective: ADHD and sleep-disordered breathing are both prevalent in adulthood. Because both conditions may be responsible for similar symptoms of cognitive impairment, the authors investigate whether their presentation may overlap in adults diagnosed with ADHD. Method: Data are collected from six adults with sleep complaints who were diagnosed…

Nasal and Oral Inspiration During Natural Speech Breathing

PubMed Central

Lester, Rosemary A.; Hoit, Jeannette D.

2015-01-01

Purpose The purpose of this study was to determine the typical pattern for inspiration during speech breathing in healthy adults, as well as the factors that might influence it. Method Ten healthy adults, 18–45 years of age, performed a variety of speaking tasks while nasal ram pressure, audio, and video recordings were obtained. Inspirations were categorized as a nasal only, oral only, simultaneous nasal and oral, or alternating nasal and oral inspiration. The method was validated using nasal airflow, oral airflow, audio, and video recordings for two participants. Results The predominant pattern was simultaneous nasal and oral inspirations for all speaking tasks. This pattern was not affected by the nature of the speaking task or by the phonetic context surrounding the inspiration. The validation procedure confirmed that nearly all inspirations during counting and paragraph reading were simultaneous nasal and oral inspirations; whereas for sentence reading, the predominant pattern was alternating nasal and oral inspirations across the three phonetic contexts. Conclusions Healthy adults inspire through both the nose and mouth during natural speech breathing. This pattern of inspiration is likely beneficial in reducing pathway resistance while preserving some of the benefits of nasal breathing. PMID:24129013

Update on diagnostic value of breath test in gastrointestinal and liver diseases

PubMed Central

Siddiqui, Imran; Ahmed, Sibtain; Abid, Shahab

2016-01-01

In the field of gastroenterology, breath tests (BTs) are used intermittently as diagnostic tools that allow indirect, non-invasive and relatively less cumbersome evaluation of several disorders by simply quantifying the appearance in exhaled breath of a metabolite of a specific substrate administered. The aim of this review is to have an insight into the principles, methods of analysis and performance parameters of various hydrogen, methane and carbon BTs which are available for diagnosing gastrointestinal disorders such as Helicobacter pylori infection, small intestinal bacterial overgrowth, and carbohydrate malabsorption. Evaluation of gastric emptying is routinely performed by scintigraphy which is however, difficult to perform and not suitable for children and pregnant women, this review has abridged the 13C-octanoic acid test in comparison to scintigraphy and has emphasized on its working protocol and challenges. A new development such as electronic nose test is also highlighted. Moreover we have also explored the limitations and constraints restraining the wide use of these BT. We conclude that breath testing has an enormous potential to be used as a diagnostic modality. In addition it offers distinct advantages over the traditional invasive methods commonly employed. PMID:27574563

DOE Office of Scientific and Technical Information (OSTI.GOV)

Latty, Drew, E-mail: drew.latty@health.nsw.gov.au; Stuart, Kirsty E; Westmead Breast Cancer Institute, Sydney, New South Wales

Radiation treatment to the left breast is associated with increased cardiac morbidity and mortality. The deep inspiration breath-hold technique (DIBH) can decrease radiation dose delivered to the heart and this may facilitate the treatment of the internal mammary chain nodes. The aim of this review is to critically analyse the literature available in relation to breath-hold methods, implementation, utilisation, patient compliance, planning methods and treatment verification of the DIBH technique. Despite variation in the literature regarding the DIBH delivery method, patient coaching, visual feedback mechanisms and treatment verification, all methods of DIBH delivery reduce radiation dose to the heart. Furthermore » research is required to determine optimum protocols for patient training and treatment verification to ensure the technique is delivered successfully.« less

Fiber-enhanced Raman multigas spectroscopy: a versatile tool for environmental gas sensing and breath analysis.

PubMed

Hanf, Stefan; Keiner, Robert; Yan, Di; Popp, Jürgen; Frosch, Torsten

2014-06-03

Versatile multigas analysis bears high potential for environmental sensing of climate relevant gases and noninvasive early stage diagnosis of disease states in human breath. In this contribution, a fiber-enhanced Raman spectroscopic (FERS) analysis of a suite of climate relevant atmospheric gases is presented, which allowed for reliable quantification of CH4, CO2, and N2O alongside N2 and O2 with just one single measurement. A highly improved analytical sensitivity was achieved, down to a sub-parts per million limit of detection with a high dynamic range of 6 orders of magnitude and within a second measurement time. The high potential of FERS for the detection of disease markers was demonstrated with the analysis of 27 nL of exhaled human breath. The natural isotopes (13)CO2 and (14)N(15)N were quantified at low levels, simultaneously with the major breath components N2, O2, and (12)CO2. The natural abundances of (13)CO2 and (14)N(15)N were experimentally quantified in very good agreement to theoretical values. A fiber adapter assembly and gas filling setup was designed for rapid and automated analysis of multigas compositions and their fluctuations within seconds and without the need for optical readjustment of the sensor arrangement. On the basis of the abilities of such miniaturized FERS system, we expect high potential for the diagnosis of clinically administered (13)C-labeled CO2 in human breath and also foresee high impact for disease detection via biologically vital nitrogen compounds.

Deep Inspiration Breath Hold—Based Radiation Therapy: A Clinical Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boda-Heggemann, Judit, E-mail: judit.boda-heggemann@umm.de; Knopf, Antje-Christin; Simeonova-Chergou, Anna

Several recent developments in linear accelerator–based radiation therapy (RT) such as fast multileaf collimators, accelerated intensity modulation paradigms like volumeric modulated arc therapy and flattening filter-free (FFF) high-dose-rate therapy have dramatically shortened the duration of treatment fractions. Deliverable photon dose distributions have approached physical complexity limits as a consequence of precise dose calculation algorithms and online 3-dimensional image guided patient positioning (image guided RT). Simultaneously, beam quality and treatment speed have continuously been improved in particle beam therapy, especially for scanned particle beams. Applying complex treatment plans with steep dose gradients requires strategies to mitigate and compensate for motion effectsmore » in general, particularly breathing motion. Intrafractional breathing-related motion results in uncertainties in dose delivery and thus in target coverage. As a consequence, generous margins have been used, which, in turn, increases exposure to organs at risk. Particle therapy, particularly with scanned beams, poses additional problems such as interplay effects and range uncertainties. Among advanced strategies to compensate breathing motion such as beam gating and tracking, deep inspiration breath hold (DIBH) gating is particularly advantageous in several respects, not only for hypofractionated, high single-dose stereotactic body RT of lung, liver, and upper abdominal lesions but also for normofractionated treatment of thoracic tumors such as lung cancer, mediastinal lymphomas, and breast cancer. This review provides an in-depth discussion of the rationale and technical implementation of DIBH gating for hypofractionated and normofractionated RT of intrathoracic and upper abdominal tumors in photon and proton RT.« less

TH-CD-202-06: A Method for Characterizing and Validating Dynamic Lung Density Change During Quiet Respiration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dou, T; Ruan, D; Heinrich, M

2016-06-15

Purpose: To obtain a functional relationship that calibrates the lung tissue density change under free breathing conditions through correlating Jacobian values to the Hounsfield units. Methods: Free-breathing lung computed tomography images were acquired using a fast helical CT protocol, where 25 scans were acquired per patient. Using a state-of-the-art deformable registration algorithm, a set of the deformation vector fields (DVF) was generated to provide spatial mapping from the reference image geometry to the other free-breathing scans. These DVFs were used to generate Jacobian maps, which estimate voxelwise volume change. Subsequently, the set of 25 corresponding Jacobian and voxel intensity inmore » Hounsfield units (HU) were collected and linear regression was performed based on the mass conservation relationship to correlate the volume change to density change. Based on the resulting fitting coefficients, the tissues were classified into parenchymal (Type I), vascular (Type II), and soft tissue (Type III) types. These coefficients modeled the voxelwise density variation during quiet breathing. The accuracy of the proposed method was assessed using mean absolute difference in HU between the CT scan intensities and the model predicted values. In addition, validation experiments employing a leave-five-out method were performed to evaluate the model accuracy. Results: The computed mean model errors were 23.30±9.54 HU, 29.31±10.67 HU, and 35.56±20.56 HU, respectively, for regions I, II, and III, respectively. The cross validation experiments averaged over 100 trials had mean errors of 30.02 ± 1.67 HU over the entire lung. These mean values were comparable with the estimated CT image background noise. Conclusion: The reported validation experiment statistics confirmed the lung density modeling during free breathing. The proposed technique was general and could be applied to a wide range of problem scenarios where accurate dynamic lung density information is needed. This work was supported in part by NIH R01 CA0096679.« less

Determination of volatile organic compounds for a systematic evaluation of third-hand smoking.

PubMed

Ueta, Ikuo; Saito, Yoshihiro; Teraoka, Kenta; Miura, Tomoya; Jinno, Kiyokatsu

2010-01-01

Third-hand smoking was quantitatively evaluated with a polymer-packed sample preparation needle and subsequent gas chromatography-mass spectroscopy analysis. The extraction needle was prepared with polymeric particles as the extraction medium, and successful extraction of typical gaseous volatile organic compounds (VOCs) was accomplished with the extraction needle. For an evaluation of this new cigarette hazard, several types of clothing fabrics were exposed to sidestream smoke, and the smoking-related VOCs evaporated from the fabrics to the environmental air were preconcentrated with the extraction needle. Smoking-related VOCs in smokers' breath were also measured using the extraction needle, and the effect of the breath VOCs on third-hand smoking pollution was evaluated. The results demonstrated that a trace amount of smoking-related VOCs was successfully determined by the proposed method. The adsorption and desorption behaviors of smoking-related VOCs were clearly different for each fabric material, and the time variations of these VOCs concentrations were quantitatively evaluated. The VOCs in the smokers' breath were clearly higher than that of nonsmokers'; however, the results suggested that no significant effect of the smokers' breath on the potential pollution occurred in the typical life space. The method was further applied to the determination of the actual third-hand smoking pollution in an automobile, and a future possibility of the proposed method to the analysis of trace amounts of VOCs in environmental air samples was suggested.

Pressure Dependence of the Radial Breathing Mode of Carbon Nanotubes: The Effect of Fluid Adsorption

NASA Astrophysics Data System (ADS)

Longhurst, M. J.; Quirke, N.

2007-04-01

The pressure dependence of shifts in the vibrational modes of individual carbon nanotubes is strongly affected by the nature of the pressure transmitting medium as a result of adsorption at the nanotube surface. The adsorbate is treated as an elastic shell which couples with the radial breathing mode (RBM) of the nanotube via van der Waal interactions. Using analytical methods as well as molecular simulation, we observe a low frequency breathing mode for the adsorbed fluid at ˜50cm-1, as well as diameter dependent upshifts in the RBM frequency with pressure, suggesting metallic nanotubes may wet more than semiconducting ones.

Micro gas analyzer measurement of nitric oxide in breath by direct wet scrubbing and fluorescence detection.

PubMed

Toda, Kei; Koga, Takahiro; Kosuge, Junichi; Kashiwagi, Mieko; Oguchi, Hiroshi; Arimoto, Takemi

2009-08-15

A novel method is proposed to measure NO in breath. Breath NO is a useful diagnostic measure for asthma patients. Due to the low water solubility of NO, existing wet chemical NO measurements are conducted on NO(2) after removal of pre-existing NO(2) and conversion of NO to NO(2). In contrast, this study utilizes direct measurement of NO by wet chemistry. Gaseous NO was collected into an aqueous phase by a honeycomb-patterned microchannel scrubber and reacted with diaminofluorescein-2 (DAF-2). Fluorescence of the product was measured using a miniature detector, comprising a blue light-emitting diode (LED) and a photodiode. The response intensity was found to dramatically increase following addition of NO(2) into the absorbing solution or air sample. By optimizing the conditions, the sensitivity obtained was sufficient to measure parts per billion by volume levels of NO continuously. The system was applied to real analysis of NO in breath, and the effect of coexisting compounds was investigated. The proposed system could successfully measure breath NO.

The potential offered by real-time, high-sensitivity monitoring of ethane in breath and some pilot studies using optical spectroscopy

NASA Astrophysics Data System (ADS)

Skeldon, Kenneth D.; Patterson, Claire; Wyse, Cathy A.; Gibson, Graham M.; Padgett, Miles J.; Longbottom, Chris; McMillan, Lesley C.

2005-06-01

Breath analysis applied to biomedical applications has gained much momentum is recent years due to the growing research demonstrating that breath gas can provide clinically useful data. Particularly exciting is the area of real-time breath analysis which, when coupled with appropriately chosen target species, can offer a novel method for non-invasive patient monitoring. Here we describe the role of ethane, a breath gas of universal appeal in assessing in vivo oxidative stress (cell damage). We first present a review of emerging applications where real-time ethane monitoring could yield original new results for healthcare. We then report on results from a portable ethane spectroscopy system (accuracy better then 100 parts per trillion (1 part in 1010) over a 1 s time response) that we have developed to exploit some of these applications. By presenting some initial results from pilot studies in the life sciences, we comment on the requirements that the next stage of optical spectroscopy technology has to meet in order to benefit clinical end-users.

Electronic response to nuclear breathing mode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ludwig, Hendrik; Ruffini, Remo; ICRANet, University of Nice-Sophia Antipolis, 28 Av. de Valrose, 06103 Nice Cedex 2

2015-12-17

Based on our previous work on stationary oscillation modes of electrons around giant nuclei, we show how to treat a general driving force on the electron gas, such as the one generated by the breathing mode of the nucleus, by means of the spectral method. As an example we demonstrate this method for a system with Z = 10{sup 4} in β-equilibrium with the electrons compressed up to the nuclear radius. In this case the stationary modes can be obtained analytically, which allows for a very speedy numerical calculation of the final result.

Respiratory muscle activity and patient–ventilator asynchrony during different settings of noninvasive ventilation in stable hypercapnic COPD: does high inspiratory pressure lead to respiratory muscle unloading?

PubMed Central

Duiverman, Marieke L; Huberts, Anouk S; van Eykern, Leo A; Bladder, Gerrie; Wijkstra, Peter J

2017-01-01

Introduction High-intensity noninvasive ventilation (NIV) has been shown to improve outcomes in stable chronic obstructive pulmonary disease patients. However, there is insufficient knowledge about whether with this more controlled ventilatory mode optimal respiratory muscle unloading is provided without an increase in patient–ventilator asynchrony (PVA). Patients and methods Ten chronic obstructive pulmonary disease patients on home mechanical ventilation were included. Four different ventilatory settings were investigated in each patient in random order, each for 15 min, varying the inspiratory positive airway pressure and backup breathing frequency. With surface electromyography (EMG), activities of the intercostal muscles, diaphragm, and scalene muscles were determined. Furthermore, pressure tracings were derived simultaneously in order to assess PVA. Results Compared to spontaneous breathing, the most pronounced decrease in EMG activity was achieved with the high-pressure settings. Adding a high breathing frequency did reduce EMG activity per breath, while the decrease in EMG activity over 1 min was comparable with the high-pressure, low-frequency setting. With high backup breathing frequencies less breaths were pressure supported (25% vs 97%). PVAs occurred more frequently with the low-frequency settings (P=0.017). Conclusion High-intensity NIV might provide optimal unloading of respiratory muscles, without undue increases in PVA. PMID:28138234

Important influence of respiration on human R-R interval power spectra is largely ignored

NASA Technical Reports Server (NTRS)

Brown, T. E.; Beightol, L. A.; Koh, J.; Eckberg, D. L.

1993-01-01

Frequency-domain analyses of R-R intervals are used widely to estimate levels of autonomic neural traffic to the human heart. Because respiration modulates autonomic activity, we determined for nine healthy subjects the influence of breathing frequency and tidal volume on R-R interval power spectra (fast-Fourier transform method). We also surveyed published literature to determine current practices in this burgeoning field of scientific inquiry. Supine subjects breathed at rates of 6, 7.5, 10, 15, 17.1, 20, and 24 breaths/min and with nominal tidal volumes of 1,000 and 1,500 ml. R-R interval power at respiratory and low (0.06-0.14 Hz) frequencies declined significantly as breathing frequency increased. R-R interval power at respiratory frequencies was significantly greater at a tidal volume of 1,500 than 1,000 ml. Neither breathing frequency nor tidal volume influenced average R-R intervals significantly. Our review of studies reporting human R-R interval power spectra showed that 51% of the studies controlled respiratory rate, 11% controlled tidal volume, and 11% controlled both respiratory rate and tidal volume. The major implications of our analyses are that breathing parameters strongly influence low-frequency as well as respiratory frequency R-R interval power spectra and that this influence is largely ignored in published research.

Usefulness of free-breathing readout-segmented echo-planar imaging (RESOLVE) for detection of malignant liver tumors: comparison with single-shot echo-planar imaging (SS-EPI).

PubMed

Tokoro, Hirokazu; Fujinaga, Yasunari; Ohya, Ayumi; Ueda, Kazuhiko; Shiobara, Aya; Kitou, Yoshihiro; Ueda, Hitoshi; Kadoya, Masumi

2014-10-01

We aimed to clarify the usefulness of free-breathing readout-segmented echo-planar imaging (RESOLVE), which is multi-shot echo-planar imaging based on a 2D-navigator-based reacquisition technique, for detecting malignant liver tumor. In 77 patients with malignant liver tumors, free-breathing RESOLVE and respiratory-triggered single-shot echo-planar imaging (SS-EPI) at 3-T MR unit were performed. We set a scan time up to approximately 5 min (300s) before examination, measured actual scan time and assessed (1) susceptibility and (2) motion artifacts in the right and left liver lobes (3, no artifact; 1, marked), and (3) detectability of malignant liver tumors (3, good; 1, poor) using a 3-point scale. The median actual scan time of RESOLVE/SS-EPI was 365/423s. The median scores of each factor in RESOLVE/SS-EPI were as following in this order: (1) 3/2 (right lobe); 3/3 (left lobe), (2) 2/3 (right lobe); 1/2 (left lobe), and (3) 3/3, respectively. Significant differences were noted between RESOLVE and SS-EPI in all evaluated factors (P<0.05) except for susceptibility of left lobe and detectability of the lesions. Despite the effect of motion artifacts, RESOLVE provides a comparable detectability of the lesion and the advantage of reducing scanning time compared with SS-EPI. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Multiple anatomy optimization of accumulated dose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watkins, W. Tyler, E-mail: watkinswt@virginia.edu; Siebers, Jeffrey V.; Moore, Joseph A.

Purpose: To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer radiation therapy compared to the internal target volume (ITV) approach. Methods: MAO aims to optimize a single fluence to be delivered under free-breathing conditions such that the accumulated dose meets the plan objectives, where accumulated dose is defined as the sum of deformably mapped doses computed on each phase of a single four dimensional computed tomography (4DCT) dataset. Phantom and patient simulation studies were carried out to investigate potential advantages of MAO compared to ITV planning. Through simulated delivery of the ITV- and MAO-plans, target dosemore » variations were also investigated. Results: By optimizing the accumulated dose, MAO shows the potential to ensure dose to the moving target meets plan objectives while simultaneously reducing dose to organs at risk (OARs) compared with ITV planning. While consistently superior to the ITV approach, MAO resulted in equivalent OAR dosimetry at planning objective dose levels to within 2% volume in 14/30 plans and to within 3% volume in 19/30 plans for each lung V20, esophagus V25, and heart V30. Despite large variations in per-fraction respiratory phase weights in simulated deliveries at high dose rates (e.g., treating 4/10 phases during single fraction beams) the cumulative clinical target volume (CTV) dose after 30 fractions and per-fraction dose were constant independent of planning technique. In one case considered, however, per-phase CTV dose varied from 74% to 117% of prescription implying the level of ITV-dose heterogeneity may not be appropriate with conventional, free-breathing delivery. Conclusions: MAO incorporates 4DCT information in an optimized dose distribution and can achieve a superior plan in terms of accumulated dose to the moving target and OAR sparing compared to ITV-plans. An appropriate level of dose heterogeneity in MAO plans must be further investigated.« less

The effect of repeated altitude exposures on the incidence of decompression sickness

NASA Technical Reports Server (NTRS)

Pilmanis, Andrew A.; Webb, James T.; Kannan, Nandini; Balldin, Ulf

2002-01-01

INTRODUCTION: Repeated altitude exposures in a single day occur during special operations parachute training, hypobaric chamber training, unpressurized flight, and extravehicular space activity. Inconsistent and contradictory information exists regarding the risk of decompression sickness (DCS) during such hypobaric exposures. HYPOTHESIS: We hypothesized that four short exposures to altitude with and without ground intervals would result in a lower incidence of DCS than a single exposure of equal duration. METHODS: The 32 subjects were exposed to 3 different hypobaric exposures--condition A: 2 h continuous exposure (control); condition B: four 30-min exposures with descent/ascent but no ground interval between the exposures; condition C: four 30-min exposures with descent/ascent and 60 min of ground interval breathing air between exposures. All exposures were to 25,000 ft with 100% oxygen breathing. Subjects were observed for symptoms of DCS, and precordial monitoring of venous gas emboli (VGE) was accomplished with a SONOS 1000 echo-imaging system. RESULTS: DCS occurred in 19 subjects during A (mean onset 70+/-29 min), 7 subjects in B (60+/-34 min), and 2 subjects in C (40+/-18 min). There was a significant difference in DCS incidence between B and A (p = 0.0015) and C and A (p = 0.0002), but no significant difference between B and C. There were 28 cases of VGE in A (mean onset 30+/-23 min), 21 in B (41+/-35 min), and 21 in C (41+/-32 min) with a significant onset curve difference between B and A and between C and A, but not between B and C. Exposure A resulted in four cases of serious respiratory/neurological symptoms, while B had one and C had none. All symptoms resolved during recompression to ground level. CONCLUSION: Data indicate that repeated simulated altitude exposures to 25,000 ft significantly reduce DCS and VGE incidence compared with a single continuous altitude exposure.

Digital versus analog complete-arch impressions for single-unit premolar implant crowns: Operating time and patient preference.

PubMed

Schepke, Ulf; Meijer, Henny J A; Kerdijk, Wouter; Cune, Marco S

2015-09-01

Digital impression-making techniques are supposedly more patient friendly and less time-consuming than analog techniques, but evidence is lacking to substantiate this assumption. The purpose of this in vivo within-subject comparison study was to examine patient perception and time consumption for 2 complete-arch impression-making methods: a digital and an analog technique. Fifty participants with a single missing premolar were included. Treatment consisted of implant therapy. Three months after implant placement, complete-arch digital (Cerec Omnicam; Sirona) and analog impressions (semi-individual tray, Impregum; 3M ESPE) were made, and the participant's opinion was evaluated with a standard questionnaire addressing several domains (inconvenience, shortness of breath, fear of repeating the impression, and feelings of helplessness during the procedure) with the visual analog scale. All participants were asked which procedure they preferred. Operating time was measured with a stopwatch. The differences between impressions made for maxillary and mandibular implants were also compared. The data were analyzed with paired and independent sample t tests, and effect sizes were calculated. Statistically significant differences were found in favor of the digital procedure regarding all subjective domains (P<.001), with medium to large effect sizes. Of all the participants, over 80% preferred the digital procedure to the analog procedure. The mean duration of digital impression making was 6 minutes and 39 seconds (SD=1:51) versus 12 minutes and 13 seconds (SD=1:24) for the analog impression (P<.001, effect size=2.7). Digital impression making for the restoration of a single implant crown takes less time than analog impression making. Furthermore, participants preferred the digital scan and reported less inconvenience, less shortness of breath, less fear of repeating the impression, and fewer feelings of helplessness during the procedure. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Computational Fluid Dynamics Investigation of Human Aspiration in Low Velocity Air: Orientation Effects on Nose-Breathing Simulations

PubMed Central

Anderson, Kimberly R.; Anthony, T. Renée

2014-01-01

An understanding of how particles are inhaled into the human nose is important for developing samplers that measure biologically relevant estimates of exposure in the workplace. While previous computational mouth-breathing investigations of particle aspiration have been conducted in slow moving air, nose breathing still required exploration. Computational fluid dynamics was used to estimate nasal aspiration efficiency for an inhaling humanoid form in low velocity wind speeds (0.1–0.4 m s−1). Breathing was simplified as continuous inhalation through the nose. Fluid flow and particle trajectories were simulated over seven discrete orientations relative to the oncoming wind (0, 15, 30, 60, 90, 135, 180°). Sensitivities of the model simplification and methods were assessed, particularly the placement of the recessed nostril surface and the size of the nose. Simulations identified higher aspiration (13% on average) when compared to published experimental wind tunnel data. Significant differences in aspiration were identified between nose geometry, with the smaller nose aspirating an average of 8.6% more than the larger nose. Differences in fluid flow solution methods accounted for 2% average differences, on the order of methodological uncertainty. Similar trends to mouth-breathing simulations were observed including increasing aspiration efficiency with decreasing freestream velocity and decreasing aspiration with increasing rotation away from the oncoming wind. These models indicate nasal aspiration in slow moving air occurs only for particles <100 µm. PMID:24665111

Identification of breathing cracks in a beam structure with entropy

NASA Astrophysics Data System (ADS)

Wimarshana, Buddhi; Wu, Nan; Wu, Christine

2016-04-01

A cantilever beam with a breathing crack is studied to detect and evaluate the crack using entropy measures. Closed cracks in engineering structures lead to proportional complexities to their vibration responses due to weak bi-linearity imposed by the crack breathing phenomenon. Entropy is a measure of system complexity and has the potential in quantifying the complexity. The weak bi-linearity in vibration signals can be amplified using wavelet transformation to increase the sensitivity of the measurements. A mathematical model of harmonically excited unit length steel cantilever beam with a breathing crack located near the fixed end is established, and an iterative numerical method is applied to generate accurate time domain dynamic responses. The bi-linearity in time domain signals due to the crack breathing are amplified by wavelet transformation first, and then the complexities due to bi-linearity is quantified using sample entropy to detect the possible crack and estimate the crack depth. It is observed that the method is capable of identifying crack depths even at very early stages of 3% with the increase in the entropy values more than 10% compared with the healthy beam. The current study extends the entropy based damage detection of rotary machines to structural analysis and takes a step further in high-sensitivity structural health monitoring by combining wavelet transformation with entropy calculations. The proposed technique can also be applied to other types of structures, such as plates and shells.

Incorporating the gas analyzer response time in gas exchange computations.

PubMed

Mitchell, R R

1979-11-01

A simple method for including the gas analyzer response time in the breath-by-breath computation of gas exchange rates is described. The method uses a difference equation form of a model for the gas analyzer in the computation of oxygen uptake and carbon dioxide production and avoids a numerical differentiation required to correct the gas fraction wave forms. The effect of not accounting for analyzer response time is shown to be a 20% underestimation in gas exchange rate. The present method accurately measures gas exchange rate, is relatively insensitive to measurement errors in the analyzer time constant, and does not significantly increase the computation time.

A Comparative Analysis of Single-Stage-To-Orbit Rocket and Air-Breathing Vehicles

DTIC Science & Technology

2006-06-01

passion to explore. I am indebted to my friends and co-workers who, through their humor and shenanigans , have made this educational experience both...the Nixon administration canceling the program, NASA enlisted financial support from the Air Force in exchange for USAF use of the Shuttle

Oxidative lung injury correlates with one-lung ventilation time during pulmonary lobectomy: a study of exhaled breath condensate and blood.

PubMed

García-de-la-Asunción, José; García-del-Olmo, Eva; Perez-Griera, Jaume; Martí, Francisco; Galan, Genaro; Morcillo, Alfonso; Wins, Richard; Guijarro, Ricardo; Arnau, Antonio; Sarriá, Benjamín; García-Raimundo, Miguel; Belda, Javier

2015-09-01

During lung lobectomy, the operated lung is collapsed and hypoperfused; oxygen deprivation is accompanied by reactive hypoxic pulmonary vasoconstriction. After lung lobectomy, ischaemia present in the collapsed state is followed by expansion-reperfusion and lung injury attributed to the production of reactive oxygen species. The primary objective of this study was to investigate the time course of several markers of oxidative stress simultaneously in exhaled breath condensate and blood and to determine the relationship between oxidative stress and one-lung ventilation time in patients undergoing lung lobectomy. This single-centre, observational, prospective study included 28 patients with non-small-cell lung cancer who underwent lung lobectomy. We measured the levels of hydrogen peroxide, 8-iso-PGF2α, nitrites plus nitrates and pH in exhaled breath condensate (n = 25). The levels of 8-iso-PGF2α and nitrites plus nitrates were also measured in blood (n = 28). Blood samples and exhaled breath condensate samples were collected from all patients at five time points: preoperatively; during one-lung ventilation, immediately before resuming two-lung ventilation; immediately after resuming two-lung ventilation; 60 min after resuming two-lung ventilation and 180 min after resuming two-lung ventilation. Both exhaled breath condensate and blood exhibited significant and simultaneous increases in oxidative-stress markers immediately before two-lung ventilation was resumed. However, all these values underwent larger increases immediately after resuming two-lung ventilation. In both exhaled breath condensate and blood, marker levels significantly and directly correlated with the duration of one-lung ventilation immediately before resuming two-lung ventilation and immediately after resuming two-lung ventilation. Although pH significantly decreased in exhaled breath condensate immediately after resuming two-lung ventilation, these pH values were inversely correlated with the duration of one-lung ventilation. During lung lobectomy, the operated lung is collapsed and oxidative injury occurs, with the levels of markers of oxidative stress increasing simultaneously in exhaled breath condensate and blood during one-lung ventilation. These increases were larger after resuming two-lung ventilation. Increases immediately before resuming two-lung ventilation and immediately after resuming two-lung ventilation were directly correlated with the duration of one-lung ventilation. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Effect of Breathing Technique of Blowing on the Extent of Damage to the Perineum at the Moment of Delivery: A Randomized Clinical Trial

PubMed Central

Ahmadi, Zohre; Torkzahrani, Shahnaz; Roosta, Firouze; Shakeri, Nezhat; Mhmoodi, Zohre

2017-01-01

Introduction: One of the important tasks in managing labor is the protection of perineum. An important variable affecting this outcome is maternal pushing during the second stage of labor. This study was done to investigate the effect of breathing technique on perineal damage extention in laboring Iranian women. Materials and Methods: This randomized clinical trial was performed on 166 nulliparous pregnant women who had reached full-term pregnancy, had low risk pregnancy, and were candidates for vaginal delivery in two following groups: using breathing techniques (case group) and valsalva maneuver (control group). In the control group, pushing was done with holding the breath. In the case group, the women were asked to take 2 deep abdominal breaths at the onset of pain, then take another deep breath, and push 4–5 seconds with the open mouth while controlling exhalation. From the crowning stage onward, the women were directed to control their pushing, and do the blowing technique. Results: According to the results, intact perineum was more observed in the case group (P = 0.002). Posterior tears (Grade 1, 2, and 3) was considerably higher in the control group (P = 0.003). Anterior tears (labias) and episiotomy were not significantly different in the two groups. Conclusions: It was concluded that breathing technique of blowing can be a good alternative to Valsalva maneuver in order to reduce perineal damage in laboring women. PMID:28382061

How to deal with morning bad breath: A randomized, crossover clinical trial.

PubMed

Oliveira-Neto, Jeronimo M; Sato, Sandra; Pedrazzi, Vinícius

2013-11-01

The absence of a protocol for the treatment of halitosis has led us to compare mouthrinses with mechanical oral hygiene procedures for treating morning breath by employing a hand-held sulfide monitor. To compare the efficacy of five modalities of treatment for controlling morning halitosis in subjects with no dental or periodontal disease. This is a five-period, randomized, crossover clinical trial. Twenty volunteers were randomly assigned to the trial. Testing involved the use of a conventional tongue scraper, a tongue scraper joined to the back of a toothbrush's head, two mouthrinses (0.05% cetylpyridinium chloride and 0.12% chlorhexidine digluconate) and a soft-bristled toothbrush and fluoride toothpaste for practicing oral hygiene. Data analysis was performed using SPSS version 17 for Windows and NCSS 2007 software (P < 0.05). The products and the periods were compared with each other using the Friedman's test. When significant differences (P < 0.05) were determined, the products and periods were compared in pairs by using the Wilcoxon's test and by adjusting the original significance level (0.05) for multiple comparisons by using the Bonferroni's method. The toothbrush's tongue scraper was able to significantly reduce bad breath for up to 2 h. Chlorhexidine reduced bad breath only at the end of the second hour, an effect that lasted for 3 h. Mechanical tongue cleaning was able to immediately reduce bad breath for a short period, whereas chlorhexidine and mechanical oral hygiene reduced bad breath for longer periods, achieving the best results against morning breath.

Breath analysis using external cavity diode lasers: a review

NASA Astrophysics Data System (ADS)

Bayrakli, Ismail

2017-04-01

Most techniques that are used for diagnosis and therapy of diseases are invasive. Reliable noninvasive methods are always needed for the comfort of patients. Owing to its noninvasiveness, ease of use, and easy repeatability, exhaled breath analysis is a very good candidate for this purpose. Breath analysis can be performed using different techniques, such as gas chromatography mass spectrometry (MS), proton transfer reaction-MS, and selected ion flow tube-MS. However, these devices are bulky and require complicated procedures for sample collection and preconcentration. Therefore, these are not practical for routine applications in hospitals. Laser-based techniques with small size, robustness, low cost, low response time, accuracy, precision, high sensitivity, selectivity, low detection limit, real-time, and point-of-care detection have a great potential for routine use in hospitals. In this review paper, the recent advances in the fields of external cavity lasers and breath analysis for detection of diseases are presented.

Nonlinear dynamics and health monitoring of 6-DOF breathing cracked Jeffcott rotor

NASA Astrophysics Data System (ADS)

Zhao, Jie; DeSmidt, Hans; Yao, Wei

2015-04-01

Jeffcott rotor is employed to study the nonlinear vibration characteristics of breathing cracked rotor system and explore the possibility of further damage identification. This paper is an extension work of prior study based on 4 degree-of-freedom Jeffcott rotor system. With consideration of disk tilting and gyroscopic effect, 6-dof EOM is derived and the crack model is established using SERR (strain energy release rate) in facture mechanics. Same as the prior work, the damaged stiffness matrix is updated by computing the instant crack closure line through Zero Stress Intensity Factor method. The breathing crack area is taken as a variable to analyze the breathing behavior in terms of eccentricity phase and shaft speed. Furthermore, the coupled vibration among lateral, torsional and longitudinal d.o.f is studied under torsional/axial excitation. The final part demonstrates the possibility of using vibration signal of damaged system for the crack diagnosis and health monitoring.

Information flow to assess cardiorespiratory interactions in patients on weaning trials.

PubMed

Vallverdú, M; Tibaduisa, O; Clariá, F; Hoyer, D; Giraldo, B; Benito, S; Caminal, P

2006-01-01

Nonlinear processes of the autonomic nervous system (ANS) can produce breath-to-breath variability in the pattern of breathing. In order to provide assess to these nonlinear processes, nonlinear statistical dependencies between heart rate variability and respiratory pattern variability are analyzed. In this way, auto-mutual information and cross-mutual information concepts are applied. This information flow analysis is presented as a short-term non linear analysis method to investigate the information flow interactions in patients on weaning trials. 78 patients from mechanical ventilation were studied: Group A of 28 patients that failed to maintain spontaneous breathing and were reconnected; Group B of 50 patients with successful trials. The results show lower complexity with an increase of information flow in group A than in group B. Furthermore, a more (weakly) coupled nonlinear oscillator behavior is observed in the series of group A than in B.

Does rhinoplasty improve nasal breathing?

PubMed

Xavier, Rui

2010-08-01

Rhinoplasty is a surgical procedure that aims to improve nasal aesthetics and nasal breathing. The aesthetic improvement of the nose is usually judged subjectively by the patient and the surgeon, but the degree of improvement of nasal obstruction is difficult to assess by clinical examination only. The measurement of peak nasal inspiratory flow (PNIF) is a reliable tool that has been shown to correlate with other objective methods of assessing nasal breathing and with patients' symptoms of nasal obstruction. Twenty-three consecutive patients undergoing rhinoplasty have been evaluated by measurement of PNIF before and after surgery. All but three patients had an increase in PNIF after surgery. The mean preoperative PNIF was 86.5 L/min and the mean postoperative PNIF was 123.0 L/min ( P < 0.001). Not surprisingly, the greatest improvement in PNIF was achieved when bilateral spreader grafts were used. This study suggests that rhinoplasty does improve nasal breathing. (c) Thieme Medical Publishers

Carbon monoxide in breath in relation to smoking and carboxyhaemoglobin levels.

PubMed Central

Wald, N J; Idle, M; Boreham, J; Bailey, A

1981-01-01

Carboxyhaemoglobin (COHb) levels were studied in 11 249 men. The distribution among the 2613 men who smoked cigarettes was well separated from that in 6641 non-smokers (including ex-smokers). The distribution for 2005 cigar and pipe smokers was intermediate, though some of the highest COHb levels occurred in cigar smokers. Using a COHb cut-off level of 2%, 81% of cigarette smokers, 35% of cigar and pipe smokers, and 1.0% of non-smokers had raised COHb levels. In a subsidiary experiment alveolar air samples were collected from 162 smokers and 25 non-smokers using a simple breath sampling technique. Carbon monoxide concentrations in alveolar breath were highly correlated with COHb levels (r = 0.97) indicating that COHb levels can be estimated reliably by measuring the concentration of carbon monoxide in breath. Alveolar carbon monoxide measurement is thus a simple method of estimating whether a person is likely to be a smoker. PMID:7314006

A rapid non invasive L-DOPA-¹³C breath test for optimally suppressing extracerebral AADC enzyme activity - toward individualizing carbidopa therapy in Parkinson’s disease.

PubMed

Modak, Anil; Durso, Raymon; Josephs, Ephraim; Rosen, David

2012-01-01

Peripheral carbidopa (CD) levels directly impact on central dopamine (DA) production in Parkinson disease (PD) through extracerebral inhibition of dopa decarboxylase (AADC) resulting in an increase in levodopa (LD) bioavailability. Recent data suggests that higher CD doses than those presently used in PD treatment may result in improved clinical response. Optimizing CD doses in individual patients may, therefore, result in ideal individualized treatment. A single center, randomized, double-blind study was carried out recruiting 5 Parkinson’s disease (PD) patients already on LD/CD and 1 treatment näve PD patient using stable isotope labeled LD-1-¹³C as a substrate for a noninvasive breath test to evaluate individual AADC enzyme activity. Each patient was studied five times, receiving 200 mg LD-¹³C at each visit along with one of five randomized CD doses (0, 25, 50, 100 and 200 mg). The metabolite ¹³CO₂ in breath was measured for evaluating AADC enzyme activity and plasma metabolite levels for LD-¹³C and homovanillic acid (HVA) were measured for 4 hours. HVA in plasma and ¹³CO₂ in breath are metabolic products of LD. We found a significant positive correlation of ¹³CO₂ DOB AUC0-240 with serum HVA AUC0-240 following the oral dose of LD-1-¹³C for all 5 doses of CD (r² = 0.9378). With increasing inhibition of AADC enzyme activity with CD, we observed an increase in the plasma concentration of LD.We found an inverse correlation of the 13CO2 DOB AUC with serum LD-¹³C AUC. Our studies indicate the optimal dose of CD for maximal suppression of AADC enzyme activity can be determined for each individual from ¹³CO₂ generation in breath. The LD-breath test can be a useful noninvasive diagnostic tool for evaluation of AADC enzyme activity using the biomarker ¹³CO₂ in breath, a first step in personalizing CD doses for PD patients.