Cardiac dosimetric evaluation of deep inspiration breath-hold level variances using computed tomography scans generated from deformable image registration displacement vectors

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

Harry, Taylor; Department of Radiation Medicine, Oregon Health and Science University, Portland, OR; Department of Nuclear Engineering and Radiation Health Physics, Oregon State University, Corvallis, OR

There is a reduction in cardiac dose for left-sided breast radiotherapy during treatment with deep inspiration breath-hold (DIBH) when compared with treatment with free breathing (FB). Various levels of DIBH may occur for different treatment fractions. Dosimetric effects due to this and other motions are a major component of uncertainty in radiotherapy in this setting. Recent developments in deformable registration techniques allow displacement vectors between various temporal and spatial patient representations to be digitally quantified. We propose a method to evaluate the dosimetric effect to the heart from variable reproducibility of DIBH by using deformable registration to create new anatomicalmore » computed tomography (CT) scans. From deformable registration, 3-dimensional deformation vectors are generated with FB and DIBH. The obtained deformation vectors are scaled to 75%, 90%, and 110% and are applied to the reference image to create new CT scans at these inspirational levels. The scans are then imported into the treatment planning system and dose calculations are performed. The average mean dose to the heart was 2.5 Gy (0.7 to 9.6 Gy) at FB, 1.2 Gy (0.6 to 3.8 Gy, p < 0.001) at 75% inspiration, 1.1 Gy (0.6 to 3.1 Gy, p = 0.004) at 90% inspiration, 1.0 Gy (0.6 to 3.0 Gy) at 100% inspiration or DIBH, and 1.0 Gy (0.6 to 2.8 Gy, p = 0.019) at 110% inspiration. The average mean dose to the left anterior descending artery (LAD) was 19.9 Gy (2.4 to 46.4 Gy), 8.6 Gy (2.0 to 43.8 Gy, p < 0.001), 7.2 Gy (1.9 to 40.1 Gy, p = 0.035), 6.5 Gy (1.8 to 34.7 Gy), and 5.3 Gy (1.5 to 31.5 Gy, p < 0.001), correspondingly. This novel method enables numerous anatomical situations to be mimicked and quantifies the dosimetric effect they have on a treatment plan.« less

Accuracy Evaluation of a 3-Dimensional Surface Imaging System for Guidance in Deep-Inspiration Breath-Hold Radiation Therapy

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

Alderliesten, Tanja; Sonke, Jan-Jakob; Betgen, Anja

2013-02-01

Purpose: To investigate the applicability of 3-dimensional (3D) surface imaging for image guidance in deep-inspiration breath-hold radiation therapy (DIBH-RT) for patients with left-sided breast cancer. For this purpose, setup data based on captured 3D surfaces was compared with setup data based on cone beam computed tomography (CBCT). Methods and Materials: Twenty patients treated with DIBH-RT after breast-conserving surgery (BCS) were included. Before the start of treatment, each patient underwent a breath-hold CT scan for planning purposes. During treatment, dose delivery was preceded by setup verification using CBCT of the left breast. 3D surfaces were captured by a surface imaging systemmore » concurrently with the CBCT scan. Retrospectively, surface registrations were performed for CBCT to CT and for a captured 3D surface to CT. The resulting setup errors were compared with linear regression analysis. For the differences between setup errors, group mean, systematic error, random error, and 95% limits of agreement were calculated. Furthermore, receiver operating characteristic (ROC) analysis was performed. Results: Good correlation between setup errors was found: R{sup 2}=0.70, 0.90, 0.82 in left-right, craniocaudal, and anterior-posterior directions, respectively. Systematic errors were {<=}0.17 cm in all directions. Random errors were {<=}0.15 cm. The limits of agreement were -0.34-0.48, -0.42-0.39, and -0.52-0.23 cm in left-right, craniocaudal, and anterior-posterior directions, respectively. ROC analysis showed that a threshold between 0.4 and 0.8 cm corresponds to promising true positive rates (0.78-0.95) and false positive rates (0.12-0.28). Conclusions: The results support the application of 3D surface imaging for image guidance in DIBH-RT after BCS.« less

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

Deep inspiration breath hold with electromagnetic confirmation of chest wall position for adjuvant therapy of left-sided breast cancer: Technique and accuracy.

PubMed

Kathpal, Madeera; Tinnel, Brent; Sun, Kelly; Ninneman, Stephanie; Malmer, Cynthia; Wendt, Stacie; Buff, Sheena; Valentich, David; Gossweiler, Marisa; Macdonald, Dusten

2016-01-01

With most patients now living long after their breast cancer diagnosis, minimizing long-term side effects of breast cancer treatment, such as reducing late cardiac and pulmonary side effects of radiation therapy (RT), is particularly important. It is now possible to use an electromagnetic tracking system to allow real-time tracking of chest wall (CW) position during the delivery of RT. Here, we report our experience using electromagnetic surface transponders as an added measure of CW position during deep inspiration breath hold (DIBH). We conducted a single-institution institutional review board-approved retrospective review of 15 female left-sided breast cancer patients treated between July 2012 and June 2013 with conventional whole breast radiation. We compared daily port films with treatment planning digitally reconstructed radiographs to establish daily setup accuracy, then used Calypso tracings to compare the position of the CW during the daily port film with the position of the CW during that day's treatment to determine the reproducibility of the breath hold position. Finally, we created competing treatment plans not using DIBH and used a paired t test to compare mean heart (MH) and left anterior descending (LAD) coronary artery dose between the 2 techniques. Mean total error (inter- and intrafraction) was dominated by interfraction error and was greatest in the longitudinal direction with a mean of 2.13 mm and 2 standard deviations of 8.2 mm. DIBH significantly reduced MH and LAD dose versus free breathing plans (MH, 1.26 Gy vs 2.84 Gy, P ≤ .001; LAD, 5.49 Gy vs 18.15 Gy, P ≤ .001). This study demonstrates that DIBH with electromagnetic confirmation of CW position is feasible, and allows potential improvement in the accurate delivery of adjuvant RT therapy for breast cancer. Published by Elsevier Inc.

SU-E-J-33: Cardiac Movement in Deep Inspiration Breath-Hold for Left-Breast Cancer Radiotherapy

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

Kim, M; Lee, S; Suh, T

Purpose: The present study was designed to investigate the displacement of heart using Deep Inspiration Breath Hold (DIBH) CT data compared to free-breathing (FB) CT data and radiation exposure to heart. Methods: Treatment planning was performed on the computed tomography (CT) datasets of 20 patients who had received lumpectomy treatments. Heart, lung and both breasts were outlined. The prescribed dose was 50 Gy divided into 28 fractions. The dose distributions in all the plans were required to fulfill the International Commission on Radiation Units and Measurement specifications that include 100% coverage of the CTV with ≥ 95% of the prescribedmore » dose and that the volume inside the CTV receiving > 107% of the prescribed dose should be minimized. Displacement of heart was measured by calculating the distance between center of heart and left breast. For the evaluation of radiation dose to heart, minimum, maximum and mean dose to heart were calculated. Results: The maximum and minimum left-right (LR) displacements of heart were 8.9 mm and 3 mm, respectively. The heart moved > 4 mm in the LR direction in 17 of the 20 patients. The distances between the heart and left breast ranged from 8.02–17.68 mm (mean, 12.23 mm) and 7.85–12.98 mm (mean, 8.97 mm) with DIBH CT and FB CT, respectively. The maximum doses to the heart were 3115 cGy and 4652 cGy for the DIBH and FB CT dataset, respectively. Conclusion: The present study has demonstrated that the DIBH technique could help to reduce the risk of radiation dose-induced cardiac toxicity by using movement of cardiac; away from radiation field. The DIBH technique could be used in an actual treatment room for a few minutes and could effectively reduce the cardiac dose when used with a sub-device or image acquisition standard to maintain consistent respiratory motion.« less

Left ventricle changes early after breath-holding in deep water in elite apnea divers.

PubMed

Pingitore, Alessandro; Gemignani, Angelo; Menicucci, Danilo; Passera, Mirko; Frassi, Francesca; Marabotti, Claudio; Piarulli, Andrea; Benassi, Antonio; L'Abbate, Antonio; Bedini, Remo

2010-01-01

To study by ultrasounds cardiac morphology and function early after breath-hold diving in deep water in elite athletes. Fifteen healthy male divers (age 28 +/- 3 years) were studied using Doppler-echocardiography, immediately before (basal condition, BC) and two minutes after breath-hold diving (40 meters, acute post-apnea condition, APAC). Each subject performed a series of three consecutive breath-hold dives (20-30 and 40 m depth). End-diastolic left ventricular (LV) diameter (EDD) and end-diastolic LV volume (EDV) increased significantly (p < 0.01). Stroke volume (SV), cardiac index (CI), septal and posterior systolic wall-thickening (SWT) also significantly increased after diving (p < 0.01). No wall motion abnormalities were detected, and wall motion score index was unchanged between BC and APAC. Doppler mitral E wave increased significantly (p < 0.01), whereas the A wave was unchanged. Systemic vascular resistance (SVR) decreased significantly after diving (p < 0.05). In the factor analysis, filtering out the absolute values smaller than 0.7 in the loading matrix, it resulted that factor I consists of EDV, posterior SWT, SV and CI, factor II of diastolic blood pressure, waves A and E and factor III of heart rate and SVR. Systo-diastolic functions were improved in the early period after deep breath-hold diving due to favorable changes in loading conditions relative to pre-diving, namely the recruitment of left ventricular preload reserve and the reduction in afterload.

Relation between lung perfusion defects and intravascular clots in acute pulmonary thromboembolism: assessment with breath-hold SPECT-CT pulmonary angiography fusion images.

PubMed

Suga, Kazuyoshi; Yasuhiko, Kawakami; Iwanaga, Hideyuki; Tokuda, Osamu; Matsunaga, Naofumi

2008-09-01

The relation between lung perfusion defects and intravascular clots in acute pulmonary thromboembolism (PTE) was comprehensively assessed on deep-inspiratory breath-hold (DIBrH) perfusion SPECT-computed tomographic pulmonary angiography (CTPA) fusion images. Subjects were 34 acute PTE patients, who had successfully performed DIBrH perfusion SPECT using a dual-headed SPECT and a respiratory tracking system. Automated DIBrH SPECT-CTPA fusion images were used to assess the relation between lung perfusion defects and intravascular clots detected by CTPA. DIBrH SPECT visualized 175 lobar/segmental or subsegmental defects in 34 patients, and CTPA visualized 61 intravascular clots at variable locations in 30 (88%) patients, but no clots in four (12%) patients. In 30 patients with clots, the fusion images confirmed that 69 (41%) perfusion defects (20 segmental, 45 subsegmental and 4 lobar defects) of total 166 defects were located in lung territories without clots, although the remaining 97 (58%) defects were located in lung territories with clots. Perfusion defect was absent in lung territories with clots (one lobar branch and three segmental branches) in four (12%) of these patients. In four patients without clots, nine perfusion defects including four segmental ones were present. Because of unexpected dissociation between intravascular clots and lung perfusion defects, the present fusion images will be a useful adjunct to CTPA in the diagnosis of acute PTE.

SU-E-J-32: Calypso(R) and Laser-Based Localization Systems Comparison for Left-Sided Breast Cancer Patients Using Deep Inspiration Breath Hold

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

Robertson, S; Kaurin, D; Sweeney, L

2014-06-01

Purpose: Our institution uses a manual laser-based system for primary localization and verification during radiation treatment of left-sided breast cancer patients using deep inspiration breath hold (DIBH). This primary system was compared with sternum-placed Calypso(R) beacons (Varian Medical Systems, CA). Only intact breast patients are considered for this analysis. Methods: During computed tomography (CT) simulation, patients have BB and Calypso(R) surface beacons positioned sternally and marked for free-breathing and DIBH CTs. During dosimetry planning, BB longitudinal displacement between free breathing and DIBH CT determines laser mark (BH mark) location. Calypso(R) beacon locations from the DIBH CT are entered at themore » Tracking Station. During Linac simulation and treatment, patients inhale until the cross-hair and/or lasers coincide with the BH Mark, which can be seen using our high quality cameras (Pelco, CA). Daily Calypso(R) displacement values (difference from the DIBH-CT-based plan) are recorded.The displacement mean and standard deviation was calculated for each patient (77 patients, 1845 sessions). An aggregate mean and standard deviation was calculated weighted by the number of patient fractions.Some patients were shifted based on MV ports. A second data set was calculated with Calypso(R) values corrected by these shifts. Results: Mean displacement values indicate agreement within 1±3mm, with improvement for shifted data (Table). Conclusion: Both unshifted and shifted data sets show the Calypso(R) system coincides with the laser system within 1±3mm, demonstrating either localization/verification system will Resultin similar clinical outcomes. Displacement value uncertainty unilaterally reduces when shifts are taken into account.« less

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.

The ins and outs of breath holding: simple demonstrations of complex respiratory physiology.

PubMed

Skow, Rachel J; Day, Trevor A; Fuller, Jonathan E; Bruce, Christina D; Steinback, Craig D

2015-09-01

The physiology of breath holding is complex, and voluntary breath-hold duration is affected by many factors, including practice, psychology, respiratory chemoreflexes, and lung stretch. In this activity, we outline a number of simple laboratory activities or classroom demonstrations that illustrate the complexity of the integrative physiology behind breath-hold duration. These activities require minimal equipment and are easily adapted to small-group demonstrations or a larger-group inquiry format where students can design a protocol and collect and analyze data from their classmates. Specifically, breath-hold duration is measured during a number of maneuvers, including after end expiration, end inspiration, voluntary prior hyperventilation, and inspired hyperoxia. Further activities illustrate the potential contribution of chemoreflexes through rebreathing and repeated rebreathing after a maximum breath hold. The outcome measures resulting from each intervention are easily visualized and plotted and can comprise a comprehensive data set to illustrate and discuss complex and integrated cardiorespiratory physiology. Copyright © 2015 The American Physiological Society.

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.

Length oscillation mimicking periodic individual deep inspirations during tidal breathing attenuates force recovery and adaptation in airway smooth muscle.

PubMed

Raqeeb, Abdul; Solomon, Dennis; Paré, Peter D; Seow, Chun Y

2010-11-01

Airway smooth muscle (ASM) is able to generate maximal force under static conditions, and this isometric force can be maintained over a large length range due to length adaptation. The increased force at short muscle length could lead to excessive narrowing of the airways. Prolonged exposure of ASM to submaximal stimuli also increases the muscle's ability to generate force in a process called force adaptation. To date, the effects of length and force adaptation have only been demonstrated under static conditions. In the mechanically dynamic environment of the lung, ASM is constantly subjected to periodic stretches by the parenchyma due to tidal breathing and deep inspiration. It is not known whether force recovery due to muscle adaptation to a static environment could occur in a dynamic environment. In this study the effect of length oscillation mimicking tidal breathing and deep inspiration was examined. Force recovery after a length change was attenuated in the presence of length oscillation, except at very short lengths. Force adaptation was abolished by length oscillation. We conclude that in a healthy lung (with intact airway-parenchymal tethering) where airways are not allowed to narrow excessively, large stretches (associated with deep inspiration) may prevent the ability of the muscle to generate maximal force that would occur under static conditions irrespective of changes in mean length; mechanical perturbation on ASM due to tidal breathing and deep inspiration, therefore, is the first line of defense against excessive bronchoconstriction that may result from static length and force adaptation.

Comparison of cardiac and lung doses for breast cancer patients with free breathing and deep inspiration breath hold technique in 3 dimensional conformal radiotherapy - a dosimetric study

NASA Astrophysics Data System (ADS)

Raj Mani, Karthick; Poudel, Suresh; Maria Das, K. J.

2017-12-01

Purpose: To investigate the cardio-pulmonary doses between Deep Inspiration Breath Hold (DIBH) and Free Breathing (FB) technique in left sided breast irradiation. Materials & Methods: DIBH CT and FB CT were acquired for 10 left sided breast patients who underwent whole breast irradiation with or without nodal irradiation. Three fields single isocenter technique were used for patients with node positive patients along with two tangential conformal fields whereas only two tangential fields were used in node negative patients. All the critical structures like lungs, heart, esophagus, thyroid, etc., were delineated in both DIBH and FB scan. Both DIBH and FB scans were fused with the Dicom origin as they were acquired with the same Dicom coordinates. Plans were created in the DIBH scan for a dose range between 50 Gy in 25 fractions. Critical structures doses were recorded from the Dose Volume Histogram for both the DIBH and FB data set for evaluation. Results: The average mean heart dose in DIBH vs FB was 13.18 Gy vs 6.97 Gy, (p = 0.0063) significantly with DIBH as compared to FB technique. The relative reduction in average mean heart dose was 47.12%. The relative V5 reduced by 14.70% (i.e. 34.42% vs 19.72%, p = 0.0080), V10 reduced by 13.83% (i.e. 27.79 % vs 13.96%, p = 0.0073). V20 reduced by 13.19% (i.e. 24.54 % vs 11.35%, p = 0.0069), V30 reduced by 12.38% (i.e. 22.27 % vs 9.89 %, p = 0.0073) significantly with DIBH as compared to FB. The average mean left lung dose reduced marginally by 1.43 Gy (13.73 Gy vs 12.30 Gy, p = 0.4599) but insignificantly with DIBH as compared to FB. Other left lung parameters (V5, V10, V20 and V30) shows marginal decreases in DIBH plans compare to FB plans. Conclusion: DIBH shows a substantial reduction of cardiac doses but slight and insignificant reduction of pulmonary doses as compared with FB technique. Using the simple DIBH technique, we can effectively reduce the cardiac morbidity and at the same time radiation induced lung

Postural Change Alters Autonomic Responses to Breath-Holding

PubMed Central

Taneja, Indu; Medow, Marvin S.; Clarke, Debbie; Ocon, Anthony; Stewart, Julian M.

2011-01-01

We used breath-holding during inspiration as a model to study the effect of pulmonary stretch on sympathetic nerve activity. Twelve healthy subjects (7 females, 5 males; 19–27 yrs) were tested while they performed an inspiratory breath-hold, both supine and during a 60° head-up tilt (HUT 60). Heart rate (HR), mean arterial blood pressure (MAP), respiration, muscle sympathetic nerve activity (MSNA), oxygen saturation (SaO2) and end tidal carbon dioxide (ETCO2) were recorded. Cardiac output (CO) and total peripheral resistance (TPR) were calculated. While breath-holding, ETCO2 increased significantly from 41±2 to 60±2 Torr during supine (p<0.05) and 38±2 Torr to 58±2 during HUT60 (p<0.05); SaO2 decreased from 98±1.5% to 95±1.4% supine, and from 97±1.5% to 94±1.7% during HUT60 (p=NS). MSNA showed three distinctive phases - a quiescent phase due to pulmonary stretch associated with decreased MAP, HR, CO and TPR; a second phase of baroreflex-mediated elevated MSNA which was associated with recovery of MAP and HR only during HUT60; CO and peripheral resistance returned to baseline while supine and HUT60; a third phase of further increased MSNA activity related to hypercapnia and associated with increased TPR. Breath-holding results in initial reductions of MSNA, MAP and HR by the pulmonary stretch reflex followed by increased sympathetic activity related to the arterial baroreflex and chemoreflex. PMID:20012144

Evaluation of sparing organs at risk (OARs) in left-breast irradiation in the supine and prone positions and with deep inspiration breath-hold.

PubMed

Saini, Amitpal Singh; Hwang, Catherine S; Biagioli, Matthew C; Das, Indra J

2018-06-21

To compare doses to organs at risk (OARs) for left-sided whole-breast radiation therapy with comparable planning target volume (PTV) coverage using three techniques: free breathing in a supine position (SFB), deep inspirational breath-hold in a supine position (SDIBH), and free breathing in prone position (PFB). Thirty-three patients with left-sided early-stage breast cancer underwent CT simulation following SFB, SDIBH, and PFB protocols for whole-breast radiation therapy. One radiation oncologist contoured the breast PTV, heart, left ventricle (LV), and left anterior descending artery (LAD). Treatment plans were optimized using field-in-field technique with the AAA algorithm. Each plan was optimized to provide identical coverage to the PTV such that a reasonable comparison for OAR dosimetry could be evaluated. All plans were prescribed 42.56 Gy in 16 fractions to the left-breast PTV. The mean dose in SFB for the heart, LV, and LAD was 1.92, 3.19, and 21.73 Gy, respectively, which were significantly higher than the mean dose in SDIBH for the heart (1.08 Gy, P ≤ 0.0001), LV (1.50 Gy, P ≤ 0.0001), and LAD (6.3 Gy, P ≤ 0.0001) and in PFB for the heart (0.98 Gy, P ≤ 0.0001), LV (1.34 Gy, P ≤ 0.0001), and LAD (6.57 Gy, P ≤ 0.0001). Similar findings were noted for the cardiac components in SFB for V2.5, V5, V10, V20, and V30 compared with values in SDIBH and PFB. The mean dose for the left lung in PFB was 0.61 Gy that was significantly lower than in SFB (5.63 Gy, P ≤ 0.0001) and SDIBH (5.54 Gy, P ≤ 0.0001). Mean dose and dosimetric values for each OAR increased in SFB and SDIBH for patients with a large breast volume compared with values for patients with a small breast volume. SFB results in higher heart, LAD, and LV doses than the other techniques. Both PFB and SDIBH are more advantageous for these OARs irrespective of breast volume. PFB results in significantly lower lung doses than SFB and SDIBH. PFB always provided better

Voluntary Deep Inspiration Breath-hold Reduces the Heart Dose Without Compromising the Target Volume Coverage During Radiotherapy for Left-sided Breast Cancer.

PubMed

Al-Hammadi, Noora; Caparrotti, Palmira; Naim, Carole; Hayes, Jillian; Rebecca Benson, Katherine; Vasic, Ana; Al-Abdulla, Hissa; Hammoud, Rabih; Divakar, Saju; Petric, Primoz

2018-03-01

During radiotherapy of left-sided breast cancer, parts of the heart are irradiated, which may lead to late toxicity. We report on the experience of single institution with cardiac-sparing radiotherapy using voluntary deep inspiration breath hold (V-DIBH) and compare its dosimetric outcome with free breathing (FB) technique. Left-sided breast cancer patients, treated at our department with postoperative radiotherapy of breast/chest wall +/- regional lymph nodes between May 2015 and January 2017, were considered for inclusion. FB-computed tomography (CT) was obtained and dose-planning performed. Cases with cardiac V25Gy ≥ 5% or risk factors for heart disease were coached for V-DIBH. Compliant patients were included. They underwent additional CT in V-DIBH for planning, followed by V-DIBH radiotherapy. Dose volume histogram parameters for heart, lung and optimized planning target volume (OPTV) were compared between FB and BH. Treatment setup shifts and systematic and random errors for V-DIBH technique were compared with FB historic control. Sixty-three patients were considered for V-DIBH. Nine (14.3%) were non-compliant at coaching, leaving 54 cases for analysis. When compared with FB, V-DIBH resulted in a significant reduction of mean cardiac dose from 6.1 +/- 2.5 to 3.2 +/- 1.4 Gy (p < 0.001), maximum cardiac dose from 51.1 +/- 1.4 to 48.5 +/- 6.8 Gy (p = 0.005) and cardiac V25Gy from 8.5 +/- 4.2 to 3.2 +/- 2.5% (p < 0.001). Heart volumes receiving low (10-20 Gy) and high (30-50 Gy) doses were also significantly reduced. Mean dose to the left anterior coronary artery was 23.0 (+/- 6.7) Gy and 14.8 (+/- 7.6) Gy on FB and V-DIBH, respectively (p < 0.001). Differences between FB- and V-DIBH-derived mean lung dose (11.3 +/- 3.2 vs. 10.6 +/- 2.6 Gy), lung V20Gy (20.5 +/- 7 vs. 19.5 +/- 5.1 Gy) and V95% for the OPTV (95.6 +/- 4.1 vs. 95.2 +/- 6.3%) were non-significant. V-DIBH-derived mean shifts for initial patient setup were ≤ 2.7 mm. Random and systematic errors

Cardiac dose reduction with deep inspiration breath hold for left-sided breast cancer radiotherapy patients with and without regional nodal irradiation.

PubMed

Yeung, Rosanna; Conroy, Leigh; Long, Karen; Walrath, Daphne; Li, Haocheng; Smith, Wendy; Hudson, Alana; Phan, Tien

2015-09-22

Deep inspiration breath hold (DIBH) reduces heart and left anterior descending artery (LAD) dose during left-sided breast radiation therapy (RT); however there is limited information about which patients derive the most benefit from DIBH. The primary objective of this study was to determine which patients benefit the most from DIBH by comparing percent reduction in mean cardiac dose conferred by DIBH for patients treated with whole breast RT ± boost (WBRT) versus those receiving breast/chest wall plus regional nodal irradiation, including internal mammary chain (IMC) nodes (B/CWRT + RNI) using a modified wide tangent technique. A secondary objective was to determine if DIBH was required to meet a proposed heart dose constraint of Dmean < 4 Gy in these two cohorts. Twenty consecutive patients underwent CT simulation both free breathing (FB) and DIBH. Patients were grouped into two cohorts: WBRT (n = 11) and B/CWRT + RNI (n = 9). 3D-conformal plans were developed and FB was compared to DIBH for each cohort using Wilcoxon signed-rank tests for continuous variables and McNemar's test for discrete variables. The percent relative reduction conferred by DIBH in mean heart and LAD dose, as well as lung V20 were compared between the two cohorts using Wilcox rank-sum testing. The significance level was set at 0.05 with Bonferroni correction for multiple testing. All patients had comparable target coverage on DIBH and FB. DIBH statistically significantly reduced mean heart and LAD dose for both cohorts. Percent reduction in mean heart and LAD dose with DIBH was significantly larger in the B/CWRT + RNI cohort compared to WBRT group (relative reduction in mean heart and LAD dose: 55.9 % and 72.1 % versus 29.2 % and 43.5 %, p < 0.02). All patients in the WBRT group and five patients (56 %) in the B/CWBRT + RNI group met heart Dmean <4 Gy with FB. All patients met this constraint with DIBH. All patients receiving WBRT met Dmean Heart�

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

Breath-holding times in various phases of respiration and effect of respiratory training in lung cancer patients.

PubMed

Tibdewal, Anil; Munshi, Anusheel; Pathak, Rima; Misra, Shagun; Daptardar, Anuradha; Singh, Vincent; Agarwal, Jai Prakash

2015-08-01

Breath-holding (BH) technique is used for reducing the intrafraction-tumour motion in mobile lung tumours treated with radiotherapy (RT). There is paucity of literature evaluating differences in BH times in various phases of respiration in patients with lung cancer. One hundred consecutive patients with lung cancer planned for radical RT/chemoradiation were accrued in the study. Eighty-seven patients were eligible for analysis at RT conclusion. Baseline pulmonary function test (PFT) were performed in all patients, and respiratory training was given from the day of RT planning. Deep inspiration breath hold (DIBH), deep expiration breath hold (DEBH) and mid-ventilation breath hold (MVBH) were recorded manually with a stopwatch for each patient at four time points (RT planning/baseline, RT starting, during RT and RT conclusion). Median DIBH times at RT planning, RT starting, during RT and RT conclusion were 21.2, 20.6, 20.1 and 21.1 s, respectively. The corresponding median DEBH and MVBH times were 16.3, 18.2, 18.3, 18.5 s and 19.9, 20.5, 21.3, 22.1 s, respectively. Respiratory training increased MVBH time at RT conclusion compared to baseline, which was statistically significant (19.9-22.1 s, P = 0.002). DIBH or DEBH times were stable at various time points with neither a significant improvement nor decline. Among various patient and tumour factors Forced Vital Capacity pre-bronchodilation (FVCpre ) was the only factor that consistently predicted DIBH, DEBH and MVBH at all four time points with P value <0.05. BH was well tolerated by most lung cancer patients with minimum median BH time of at least 16 s in any of the three phases of respiration. Respiratory training improved MVBH time while consistently maintaining DIBH and DEBH times throughout the course of radiotherapy. © 2015 The Royal Australian and New Zealand College of Radiologists.

Preliminary observations on the effect of hypoxic and hyperbaric stress on pulmonary gas exchange in breath-hold divers.

PubMed

Garbella, Erika; Piarulli, Andrea; Fornai, Edo; Pingitore, Alessandro; Prediletto, Renato

2011-06-01

To evaluate pulmonary alveolar-capillary membrane integrity and ventilation/perfusion mismatch after breath-hold diving. Pulmonary diffusing capacity to carbon monoxide (DLCO) and nitric oxide (DLNO), haemoglobin (Hb) and haematocrit (Hct) were measured in six elite divers before and at 2, 10 and 25 minutes after a maximal breath-hold dive to a depth of 10 metres' sea water. Compared to pre-dive, DLCO showed a slight increase at 2 minutes in five subjects and a tendency to decrease at 25 minutes (P < 0.001) in all subjects. DLNO showed an increase at 10 minutes in three divers and a slight decrease at 25 minutes in five subjects. There was a small but significant (P < 0.001) increase in Hb and Hct at 2 minutes, possibly affecting the DLCO measurements. An early but transient increase in DLCO in five divers may reflect the central shift in blood volume during a breath-hold dive. The late parallel decrease in DLCO and DLNO likely reflects alveolar-capillary distress (interstitial oedema). The DLNO increase in three subjects at 10 minutes may suggest ventilation/perfusion mismatch.

Feasibility of deep-inspiration breath-hold PET/CT with short-time acquisition: detectability for pulmonary lesions compared with respiratory-gated PET/CT.

PubMed

Yamashita, Shozo; Yokoyama, Kunihiko; Onoguchi, Masahisa; Yamamoto, Haruki; Hiko, Shigeaki; Horita, Akihiro; Nakajima, Kenichi

2014-01-01

Deep-inspiration breath-hold (DIBH) PET/CT with short-time acquisition and respiratory-gated (RG) PET/CT are performed for pulmonary lesions to reduce the respiratory motion artifacts, and to obtain more accurate standardized uptake value (SUV). DIBH PET/CT demonstrates significant advantages in terms of rapid examination, good quality of CT images and low radiation exposure. On the other hand, the image quality of DIBH PET is generally inferior to that of RG PET because of short-time acquisition resulting in poor signal-to-noise ratio. In this study, RG PET has been regarded as a gold standard, and its detectability between DIBH and RG PET studies was compared using each of the most optimal reconstruction parameters. In the phantom study, the most optimal reconstruction parameters for DIBH and RG PET were determined. In the clinical study, 19 cases were examined using each of the most optimal reconstruction parameters. In the phantom study, the most optimal reconstruction parameters for DIBH and RG PET were different. Reconstruction parameters of DIBH PET could be obtained by reducing the number of subsets for those of RG PET in the state of fixing the number of iterations. In the clinical study, high correlation in the maximum SUV was observed between DIBH and RG PET studies. The clinical result was consistent with that of the phantom study surrounded by air since most of the lesions were located in the low pulmonary radioactivity. DIBH PET/CT may be the most practical method which can be the first choice to reduce respiratory motion artifacts if the detectability of DIBH PET is equivalent with that of RG PET. Although DIBH PET may have limitations in suboptimal signal-to-noise ratio, most of the lesions surrounded by low background radioactivity could provide nearly equivalent image quality between DIBH and RG PET studies when each of the most optimal reconstruction parameters was used.

Sports-related lung injury during breath-hold diving.

PubMed

Mijacika, Tanja; Dujic, Zeljko

2016-12-01

The number of people practising recreational breath-hold diving is constantly growing, thereby increasing the need for knowledge of the acute and chronic effects such a sport could have on the health of participants. Breath-hold diving is potentially dangerous, mainly because of associated extreme environmental factors such as increased hydrostatic pressure, hypoxia, hypercapnia, hypothermia and strenuous exercise.In this article we focus on the effects of breath-hold diving on pulmonary function. Respiratory symptoms have been reported in almost 25% of breath-hold divers after repetitive diving sessions. Acutely, repetitive breath-hold diving may result in increased transpulmonary capillary pressure, leading to noncardiogenic oedema and/or alveolar haemorrhage. Furthermore, during a breath-hold dive, the chest and lungs are compressed by the increasing pressure of water. Rapid changes in lung air volume during descent or ascent can result in a lung injury known as pulmonary barotrauma. Factors that may influence individual susceptibility to breath-hold diving-induced lung injury range from underlying pulmonary or cardiac dysfunction to genetic predisposition.According to the available data, breath-holding does not result in chronic lung injury. However, studies of large populations of breath-hold divers are necessary to firmly exclude long-term lung damage. Copyright ©ERS 2016.

A sigh of relief or a sigh to relieve: The psychological and physiological relief effect of deep breaths.

PubMed

Vlemincx, Elke; Van Diest, Ilse; Van den Bergh, Omer

2016-10-15

Both animal and human research have revealed important associations between sighs and relief. Previously we argued to conceive of sighs as resetters which temporarily induce relief. The present study aimed to investigate the psychological and physiological relief effect of sighs by instructed deep breaths and spontaneous sighs compared to a control breathing maneuver. Participants completed three blocks of 40 trials during which uncertainty cues were followed by either safety cues followed by a positive picture, or danger cues followed by a negative picture. One block was presented without breathing instructions, two subsequent blocks with breathing instructions. During the presentation of the safety and danger cues, an instruction was given to either 'take a deep breath' or 'postpone the next inhalation for 2 s (breath hold). Continuously, participants rated relief and Frontalis electromyography was recorded. Trait anxiety sensitivity was assessed by the Anxiety Sensitivity Index. Self-reported relief and physiological tension were compared 5s before and after instructed deep breaths and breath holds, and before and after spontaneous deep breaths and breath holds in the respective blocks. Results show that self-reported relief following an instructed deep breath was higher than before. Physiological tension decreased following a spontaneous sigh in high anxiety sensitive persons and following a spontaneous breath hold in low anxiety sensitive persons. These results are the first to show that a deep breath relieves and, in anxiety sensitive persons, reduces physiological tension. These findings support the hypothesis that sighs are psychological and physiological resetters. Copyright © 2016 Elsevier Inc. All rights reserved.

Functional Analysis and Intervention for Breath Holding.

ERIC Educational Resources Information Center

Kern, Lee; And Others

1995-01-01

A functional analysis of breath-holding episodes in a 7-year-old girl with severe mental retardation and Cornelia-de-Lange syndrome indicated that breath holding served an operant function, primarily to gain access to attention. Use of extinction, scheduled attention, and a picture card communication system decreased breath holding. (Author/SW)

SU-E-T-450: How Important Is a Reproducible Breath Hold for DIBH Breast Radiotherapy?

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

Liu, H; Wentworth, S; Sintay, B

Purpose: Deep inspiration breath hold (DIBH) for left-sided breast cancer has been shown to reduce heart dose. Surface imaging helps to ensure accurate breast positioning, but does not guarantee a reproducible breath hold (BH) at DIBH treatments. We examine the effects of variable BH positions for DIBH treatments. Methods: Twenty-Five patients with free breathing (FB) and DIBH scans were reviewed. Four plans were created for each patient: 1) FB, 2) DIBH, 3) FB-DIBH – the DIBH plans were copied to the FB images and recalculated (image registration was based on breast tissue), and 4) P-DIBH – a partial BH withmore » the heart shifted midway between the FB and DIBH positions. The FB-DIBH plans give “worst case” scenarios for surface imaging DIBH, where the breast is aligned by surface imaging but the patient is not holding their breath. Students t-tests were used to compare dose metrics. Results: The DIBH plans gave lower heart dose and comparable breast coverage versus FB in all cases. The FB-DIBH plans showed no significant difference versus FB plans for breast coverage, mean heart dose, or maximum heart dose (p >= 0.10). The mean heart dose differed between FB-DIBH and FB by < 2 Gy for all cases, the maximum heart dose differed by < 2 Gy for 21 cases. The P-DIBH plans showed significantly lower mean heart dose than FB (p = 0.01). The mean heart doses for the P-DIBH plans were < FB for 22 cases, the maximum dose < FB for 18 cases. Conclusions: A DIBH plan delivered to a FB patient set-up with surface imaging will yield similar dosimetry to a plan created and delivered FB. A DIBH plan delivered with even a partial BH can give reduced heart dose compared to FB techniques when the breast tissue is well aligned.« less

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

Cardiac dose-sparing effects of deep-inspiration breath-hold in left breast irradiation : Is IMRT more beneficial than VMAT?

PubMed

Sakka, Mazen; Kunzelmann, Leonie; Metzger, Martin; Grabenbauer, Gerhard G

2017-10-01

Given the reduction in death from breast cancer, as well as improvements in overall survival, adjuvant radiotherapy is considered the standard treatment for breast cancer. However, left-sided breast irradiation was associated with an increased rate of fatal cardiovascular events due to incidental irradiation of the heart. Recently, considerable efforts have been made to minimize cardiac toxicity of left-sided breast irradiation by new treatment methods such as deep-inspiration breath-hold (DIBH) and new radiation techniques, particularly intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT). The primary aim of this study was to evaluate the effect of DIBH irradiation on cardiac dose compared with free-breathing (FB) irradiation, while the secondary objective was to compare the advantages of IMRT versus VMAT plans in both the FB and the DIBH position for left-sided breast cancer. In all, 25 consecutive left-sided breast cancer patients underwent CT simulation in the FB and DIBH position. Five patients were excluded with no cardiac displacement following DIBH-CT simulation. The other 20 patients were irradiated in the DIBH position using respiratory gating. Four different treatment plans were generated for each patient, an IMRT and a VMAT plan in the DIBH and in the FB position, respectively. The following parameters were used for plan comparison: dose to the heart, left anterior descending coronary artery (mean dose, maximum dose, D25% and D45%), ipsilateral, contralateral lung (mean dose, D20%, D30%) and contralateral breast (mean dose). The percentage in dose reduction for organs at risk achieved by DIBH for both IMRT and VMAT plans was calculated and compared for each patient by each treatment plan. DIBH irradiation significantly reduced mean dose to the heart and left anterior descending coronary artery (LADCA) using both IMRT (heart -20%; p = 0.0002, LADCA -9%; p = 0.001) and VMAT (heart -23%; p = 0.00003, LADCA -16%; p = 0

[Assessment of influence of breath holding and hyperventilation on human postural stability with spectral analysis of stabilographic signal].

PubMed

Malakhov, M V; Makarenkova, E A; Mel'nikov, A A; Vikulov, A D

2014-01-01

The influence of breath holding and voluntary hyperventilation on the classic stabilometric parameters and the frequency characteristic of stabilographic signal were studied. We measured the stabilometric parameters on the force platform ("Ritm", Russia) on the healthy volunteers (n = 107) during quiet breath, voluntary hyperventilation (20 seconds) and maximal inspiratory breath holding (20 seconds). Respiratory frequency, respiratory amplitude and ventilation were estimated with strain gauge. We found that antero-posterior and medio-lateral sway amplitude and velocity as well as sway surface at breath-holding and at quiet breathing were the same, so breath holding didn't influence the postural stability. However the spectral parameters shifted to the high frequency range due to alteration of the respiratory muscles contractions during breath-holding versus quiet breath. Voluntary hyperventilation caused significant increase of all stabilographic indices that implied an impairment of postural stability, which was due to the increase of respiration frequency and amplitude. We also found that the spectral indices moved toward the high-frequency range with more pronounced degree of this shift versus breath holding. Besides, amplitudes of spectral peaks also increased. Perhaps such change of spectral indices was due to distortion of proprioceptive information because of increased excitability of nerve fibers during hyperventilation. Maximal inspiration breath holding causes strain of the postural control mechanisms that is reflected as elevation of postural sway frequency with no postural stability changes. Hyperventilation leads to the most prominent strain of balance function and decrease of steadiness that is manifested as increase of center of pressure oscillations amplitude and frequency.

Acute Effects of Cannabis on Breath-Holding Duration

PubMed Central

Farris, Samantha G.; Metrik, Jane

2016-01-01

Distress intolerance (an individual’s perceived or actual inability to tolerate distressing psychological or physiological states) is associated with cannabis use. It is unknown whether a bio-behavioral index of distress intolerance, breath-holding duration, is acutely influenced (increased or decreased) by cannabis. Such information may further inform understanding of the expression of psychological or physiological distress post-cannabis use. This within-subjects study examined whether smoked marijuana with 2.7–3.0 % delta-9-tetrahydrocannabinol (THC), relative to placebo, acutely changed duration of breath-holding. Participants (n = 88; 65.9% male) were non-treatment seeking frequent cannabis users who smoked placebo or active THC cigarette on two separate study days and completed breath-holding task. Controlling for baseline breath-holding duration and participant sex, THC produced significantly lower breath-holding durations relative to placebo. There was a significant interaction of drug administration x frequency of cannabis use, such that THC decreased breath-holding time among less frequent but not among more frequent users. Findings indicate that cannabis may be exacerbating distress intolerance (via breath-holding duration). As compared to less frequent cannabis users, frequent users display tolerance to cannabis’ acute effects including increased ability to tolerate respiratory distress when holding breath. Objective measures of distress intolerance are sensitive to contextual factors such as acute drug intoxication, and may inform the link between cannabis use and the expression of psychological distress. PMID:27454678

Facial immersion in cold water enhances cerebral blood velocity during breath-hold exercise in humans.

PubMed

Kjeld, Thomas; Pott, Frank C; Secher, Niels H

2009-04-01

The diving response is initiated by apnea and facial immersion in cold water and includes, besides bradycardia, peripheral vasoconstriction, while cerebral perfusion may be enhanced. This study evaluated whether facial immersion in 10 degrees C water has an independent influence on cerebral perfusion evaluated as the middle cerebral artery mean flow velocity (MCA V(mean)) during exercise in nine male subjects. At rest, a breath hold of maximum duration increased the arterial carbon dioxide tension (Pa(CO(2))) from 4.2 to 6.7 kPa and MCA V(mean) from 37 to 103 cm/s (mean; approximately 178%; P < 0.001). Similarly, during 100-W exercise, a breath hold increased Pa(CO(2)) from 5.9 to 8.2 kPa (P < 0.001) and MCA V(mean) from 55 to 113 cm/s ( approximately 105%), and facial immersion further increased MCA V(mean) to 122 cm/s ( approximately 88%; both P < 0.001). MCA V(mean) also increased during 180-W exercise (from 47 to 53 cm/s), and this increment became larger with facial immersion (76 cm/s, approximately 62%; P < 0.001), although Pa(CO(2)) did not significantly change. These results indicate that a breath hold diverts blood toward the brain with a >100% increase in MCA V(mean), largely because Pa(CO(2)) increases, but the increase in MCA V(mean) becomes larger when combined with facial immersion in cold water independent of Pa(CO(2)).

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.

Horses Auto-Recruit Their Lungs by Inspiratory Breath Holding Following Recovery from General Anaesthesia

PubMed Central

Mosing, Martina; Waldmann, Andreas D.; MacFarlane, Paul; Iff, Samuel; Auer, Ulrike; Bohm, Stephan H.; Bettschart-Wolfensberger, Regula; Bardell, David

2016-01-01

This study evaluated the breathing pattern and distribution of ventilation in horses prior to and following recovery from general anaesthesia using electrical impedance tomography (EIT). Six horses were anaesthetised for 6 hours in dorsal recumbency. Arterial blood gas and EIT measurements were performed 24 hours before (baseline) and 1, 2, 3, 4, 5 and 6 hours after horses stood following anaesthesia. At each time point 4 representative spontaneous breaths were analysed. The percentage of the total breath length during which impedance remained greater than 50% of the maximum inspiratory impedance change (breath holding), the fraction of total tidal ventilation within each of four stacked regions of interest (ROI) (distribution of ventilation) and the filling time and inflation period of seven ROI evenly distributed over the dorso-ventral height of the lungs were calculated. Mixed effects multi-linear regression and linear regression were used and significance was set at p<0.05. All horses demonstrated inspiratory breath holding until 5 hours after standing. No change from baseline was seen for the distribution of ventilation during inspiration. Filling time and inflation period were more rapid and shorter in ventral and slower and longer in most dorsal ROI compared to baseline, respectively. In a mixed effects multi-linear regression, breath holding was significantly correlated with PaCO2 in both the univariate and multivariate regression. Following recovery from anaesthesia, horses showed inspiratory breath holding during which gas redistributed from ventral into dorsal regions of the lungs. This suggests auto-recruitment of lung tissue which would have been dependent and likely atelectic during anaesthesia. PMID:27331910

Breath holding spell

MedlinePlus

... such as Riley-Day syndrome or Rett syndrome Iron deficiency anemia A family history of breath holding spells ( ... tests may be done to check for an iron deficiency. Other tests that may be done include: EKG ...

SU-F-T-254: Dose Volume Histogram (DVH) Analysis of Breath Hold Vs Free Breathing Techniques for Esophageal Tumors

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

Badkul, R; Doke, K; Pokhrel, D

Purpose: Lung and heart doses and associated toxicity are of concern in radiotherapy for esophageal cancer. This study evaluates the dosimetry of deep-inspiration-breath-hold (DIBH) technique as compared to freebreathing( FB) using 3D-conformal treatment(3D-CRT) of esophageal cancer. Methods: Eight patients were planned with FB and DIBH CT scans. DIBH scans were acquired using Varian RPM system. FB and DIBH CTs were contoured per RTOG-1010 to create the planning target volume(PTV) as well as organs at risk volumes(OAR). Two sets of gross target volumes(GTV) with 5cm length were contoured for each patient: proximal at the level of the carina and distal atmore » the level of gastroesophageal junction and were enlarged with appropriate margin to generate Clinical Target Volume and PTV. 3D-CRT plans were created on Eclipse planning system for 45Gy to cover 95% of PTV in 25 fractions for both proximal and distal tumors on FB and DIBH scans. For distal tumors celiac nodes were covered electively. DVH parameters for lung and heart OARs were generated and analyzed. Results: All DIBH DVH parameters were normalized to FB plan values. Average of heart-mean and heart-V40 was 0.70 and 0.66 for proximal lesions. For distal lesions ratios were 1.21 and 2.22 respectively. For DIBH total lung volume increased by 2.43 times versus FB scan. Average of lung-mean, V30, V20, V10, V5 are 0.82, 0.92, 0.76, 0.77 and 0.79 for proximal lesions and 1.17,0.66,0.87,0.93 and 1.03 for distal lesions. Heart doses were lower for breath-hold proximal lesions but higher for distal lesions as compared to free-breathing plans. Lung doses were lower for both proximal and distal breath-hold lesions except mean lung dose and V5 for distal lesions. Conclusion: This study showed improvement of OAR doses for esophageal lesions at mid-thoracic level utilizing DIBH vs FB technique but did not show consistent OAR sparing with DIBH for distal lesions.« less

Breath-Holding Spells

MedlinePlus

... reviewed: October 2016 More on this topic for: Parents Is It Normal for Children to Hold Their Breath? Taming Tempers Disciplining Your Child Disciplining Your Toddler Temper Tantrums Separation Anxiety View more About Us Contact Us Partners ...

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.

Deep breathing after surgery

MedlinePlus

... and taking big breaths can be uncomfortable. A device called an incentive spirometer can help you take deep breaths correctly. If you do not have this device, you can still practice deep breathing on your ...

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.

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.

Effects of depth and chest volume on cardiac function during breath-hold diving.

PubMed

Marabotti, Claudio; Scalzini, Alessandro; Cialoni, Danilo; Passera, Mirko; Ripoli, Andrea; L'Abbate, Antonio; Bedini, Remo

2009-07-01

Cardiac response to breath-hold diving in human beings is primarily characterized by the reduction of both heart rate and stroke volume. By underwater Doppler-echocardiography we observed a "restrictive/constrictive" left ventricular filling pattern compatible with the idea of chest squeeze and heart compression during diving. We hypothesized that underwater re-expansion of the chest would release heart constriction and normalize cardiac function. To this aim, 10 healthy male subjects (age 34.2 +/- 10.4) were evaluated by Doppler-echocardiography during breath-hold immersion at a depth of 10 m, before and after a single maximal inspiration from a SCUBA device. During the same session, all subjects were also studied at surface (full-body immersion) and at 5-m depth in order to better characterize the relationship of echo-Doppler pattern with depth. In comparison to surface immersion, 5-m deep diving was sufficient to reduce cardiac output (P = 0.042) and increase transmitral E-peak velocity (P < 0.001). These changes remained unaltered at a 10-m depth. Chest expansion at 10 m decreased left ventricular end-systolic volume (P = 0.024) and increased left ventricular stroke volume (P = 0.024). In addition, it decreased transmitral E-peak velocity (P = 0.012) and increased deceleration time of E-peak (P = 0.021). In conclusion the diving response, already evident during shallow diving (5 m) did not progress during deeper dives (10 m). The rapid improvement in systolic and diastolic function observed after lung volume expansion is congruous with the idea of a constrictive effect on the heart exerted by chest squeeze.

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

Accelerating free breathing myocardial perfusion MRI using multi coil radial k - t SLR

NASA Astrophysics Data System (ADS)

Goud Lingala, Sajan; DiBella, Edward; Adluru, Ganesh; McGann, Christopher; Jacob, Mathews

2013-10-01

The clinical utility of myocardial perfusion MR imaging (MPI) is often restricted by the inability of current acquisition schemes to simultaneously achieve high spatio-temporal resolution, good volume coverage, and high signal to noise ratio. Moreover, many subjects often find it difficult to hold their breath for sufficiently long durations making it difficult to obtain reliable MPI data. Accelerated acquisition of free breathing MPI data can overcome some of these challenges. Recently, an algorithm termed as k - t SLR has been proposed to accelerate dynamic MRI by exploiting sparsity and low rank properties of dynamic MRI data. The main focus of this paper is to further improve k - t SLR and demonstrate its utility in considerably accelerating free breathing MPI. We extend its previous implementation to account for multi-coil radial MPI acquisitions. We perform k - t sampling experiments to compare different radial trajectories and determine the best sampling pattern. We also introduce a novel augmented Lagrangian framework to considerably improve the algorithm’s convergence rate. The proposed algorithm is validated using free breathing rest and stress radial perfusion data sets from two normal subjects and one patient with ischemia. k - t SLR was observed to provide faithful reconstructions at high acceleration levels with minimal artifacts compared to existing MPI acceleration schemes such as spatio-temporal constrained reconstruction and k - t SPARSE/SENSE.

Accelerating free breathing myocardial perfusion MRI using multi coil radial k-t SLR

PubMed Central

Lingala, Sajan Goud; DiBella, Edward; Adluru, Ganesh; McGann, Christopher; Jacob, Mathews

2013-01-01

The clinical utility of myocardial perfusion MR imaging (MPI) is often restricted by the inability of current acquisition schemes to simultaneously achieve high spatio-temporal resolution, good volume coverage, and high signal to noise ratio. Moreover, many subjects often find it difficult to hold their breath for sufficiently long durations making it difficult to obtain reliable MPI data. Accelerated acquisition of free breathing MPI data can overcome some of these challenges. Recently, an algorithm termed as k − t SLR has been proposed to accelerate dynamic MRI by exploiting sparsity and low rank properties of dynamic MRI data. The main focus of this paper is to further improve k − t SLR and demonstrate its utility in considerably accelerating free breathing MPI. We extend its previous implementation to account for multi-coil radial MPI acquisitions. We perform k − t sampling experiments to compare different radial trajectories and determine the best sampling pattern. We also introduce a novel augmented Lagrangian framework to considerably improve the algorithm's convergence rate. The proposed algorithm is validated using free breathing rest and stress radial perfusion data sets from two normal subjects and one patient with ischemia. k − t SLR was observed to provide faithful reconstructions at high acceleration levels with minimal artifacts compared to existing MPI acceleration schemes such as spatio-temporal constrained reconstruction (STCR) and k − t SPARSE/SENSE. PMID:24077063

Hyperbaric nitrogen prolongs breath-holding time in humans.

PubMed

Morooka, H; Wakasugi, Y; Shimamoto, H; Shibata, O; Sumikawa, K

2000-09-01

Either an increase in PaCO(2) or a decrease in PaO(2), can affect respiratory stimulation through respiratory centers, thus influencing breath-holding time (BHT). This study was designed to determine whether and how hyperbaric air could influence BHT in comparison with hyperbaric oxygen in humans. We studied 36 healthy volunteers in a multiplace hyperbaric chamber. BHT, pulse oximeter, and transcutaneous carbon dioxide tension were measured at 1 and 2.8 atmosphere absolute (ATA) in two groups. Group A (n = 20) breathed air. Group O (n = 16) breathed oxygen with a face mask (5 L/min). BHTs were 108 +/- 28 s at 1.0 ATA and 230 +/- 71 s at 2.8 ATA in Group A, and 137 +/- 48 s at 1.0 ATA and 180 +/- 52 s at 2.8 ATA in Group O. Transcutaneous carbon dioxide tension in Group A (59 +/- 2 mm Hg) was higher than that in Group O (54 +/- 2 mm Hg) at the end of maximal breath-holding at 2.8 ATA. The prolongation of BHT in hyperbaric air is significantly greater than that in hyperbaric oxygen. Breath-holding time is significantly prolonged in hyperbaric air than it is in hyperbaric oxygen. The mechanism involves the anesthetic effect of nitrogen suppressing the suffocating feeling during breath-holding.

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

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

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

Breath-hold times in air compared to breath-hold times during cold water immersions.

PubMed

Taber, Michael J; MacKinnon, Scott N; Power, Jonathan; Walker, Robert

2015-02-01

Given the effects of cold water immersion on breath-hold (BH) capabilities, a practical training exercise was developed for military/paramilitary personnel completing a helicopter underwater egress training (HUET) program. The exercise was designed to provide firsth and experience of the effects of cold water exposure on BH time. After completing the required HUET, 47 subjects completed two BH testing sessions as well as a short questionnaire. The first BH was completed while standing on the pool deck. The second BH was completed while fully immersed (face down) in 2-3°C water. There were 40 of the volunteers who also breathed from an emergency breathing system (EBS) while in the cold water. Results demonstrated that BH capabilities in cold water were significantly lower than those in ambient air. A significant correlation was also found between BH in air and the difference in cold water vs. air BH capabilities, which suggests that subjects who can hold their breath the longest in air experienced the greatest decrease in BH when immersed. Results indicate that 92% of the subjects reported that the practical cold water immersion exercise had a high value. Finally, 58% of those who used the EBS reported that it was harder to breathe in cold water than while in the training pool (approximately 22°C). The BH times for this group were similar to those reported in previous cold water immersion studies. Based on the questionnaire results, it is possible, when carefully applied, to include a practical cold water immersion exercise into existing HUET programs.

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.

Practice It: Deep Conscious Breathing Exercise

Cancer.gov

No time to sit and breathe? No problem; take your breathing practice with you! Deep conscious breathing can also be done with the eyes open wherever you happen to be—simply pause and take two to three full deep breaths (inhale deeply and exhale completely).

Asystole and increased serum myoglobin levels associated with 'packing blackout' in a competitive breath-hold diver.

PubMed

Andersson, Johan P A; Linér, Mats H; Jönsson, Henrik

2009-11-01

Many competitive breath-hold divers use 'glossopharyngeal insufflation', also called 'lung packing', to overfill their lungs above normal total lung capacity. This increases intrathoracic pressure, decreases venous return, compromises cardiac pumping, and reduces arterial blood pressure, possibly resulting in a syncope breath-hold divers call 'packing blackout'. We report a case with a breath-hold diver who inadvertently experienced a packing blackout. During the incident, an electrocardiogram (ECG) and blood pressure were recorded, and blood samples for determinations of biomarkers of cardiac muscle perturbation (creatine kinase-MB isoenzyme (CK-MB), cardiac troponin-T (TnT), and myoglobin) were collected. The ECG revealed short periods of asystole during the period of 'packing blackout', simultaneous with pronounced reductions in systolic, diastolic, and pulse pressures. Serum myoglobin concentration was elevated 40 and 150 min after the incident, whereas there were no changes in CK-MB or TnT. The ultimate cause of syncope in this diver probably was a decrease in cerebral perfusion following glossopharyngeal insufflation. The asystolic periods recorded in this diver could possibly indicate that susceptible individuals may be put at risk of a serious cardiac incident if the lungs are excessively overinflated by glossopharyngeal insufflation. This concern is further substantiated by the observed increase in serum myoglobin concentration after the event.

Localized Spatio-Temporal Constraints for Accelerated CMR Perfusion

PubMed Central

Akçakaya, Mehmet; Basha, Tamer A.; Pflugi, Silvio; Foppa, Murilo; Kissinger, Kraig V.; Hauser, Thomas H.; Nezafat, Reza

2013-01-01

Purpose To develop and evaluate an image reconstruction technique for cardiac MRI (CMR)perfusion that utilizes localized spatio-temporal constraints. Methods CMR perfusion plays an important role in detecting myocardial ischemia in patients with coronary artery disease. Breath-hold k-t based image acceleration techniques are typically used in CMR perfusion for superior spatial/temporal resolution, and improved coverage. In this study, we propose a novel compressed sensing based image reconstruction technique for CMR perfusion, with applicability to free-breathing examinations. This technique uses local spatio-temporal constraints by regularizing image patches across a small number of dynamics. The technique is compared to conventional dynamic-by-dynamic reconstruction, and sparsity regularization using a temporal principal-component (pc) basis, as well as zerofilled data in multi-slice 2D and 3D CMR perfusion. Qualitative image scores are used (1=poor, 4=excellent) to evaluate the technique in 3D perfusion in 10 patients and 5 healthy subjects. On 4 healthy subjects, the proposed technique was also compared to a breath-hold multi-slice 2D acquisition with parallel imaging in terms of signal intensity curves. Results The proposed technique results in images that are superior in terms of spatial and temporal blurring compared to the other techniques, even in free-breathing datasets. The image scores indicate a significant improvement compared to other techniques in 3D perfusion (2.8±0.5 vs. 2.3±0.5 for x-pc regularization, 1.7±0.5 for dynamic-by-dynamic, 1.1±0.2 for zerofilled). Signal intensity curves indicate similar dynamics of uptake between the proposed method with a 3D acquisition and the breath-hold multi-slice 2D acquisition with parallel imaging. Conclusion The proposed reconstruction utilizes sparsity regularization based on localized information in both spatial and temporal domains for highly-accelerated CMR perfusion with potential utility in free-breathing

Quantifying the Reproducibility of Heart Position During Treatment and Corresponding Delivered Heart Dose in Voluntary Deep Inhalation Breath Hold for Left Breast Cancer Patients Treated With External Beam Radiotherapy

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

McIntosh, Alyson; Shoushtari, Asal N.; Benedict, Stanley H.

Purpose: Voluntary deep inhalation breath hold (VDIBH) reduces heart dose during left breast irradiation. We present results of the first study performed to quantify reproducibility of breath hold using bony anatomy, heart position, and heart dose for VDIBH patients at treatment table. Methods and Materials: Data from 10 left breast cancer patients undergoing VDIBH whole-breast irradiation were analyzed. Two computed tomography (CT) scans, free breathing (FB) and VDIBH, were acquired to compare dose to critical structures. Pretreatment weekly kV orthogonal images and tangential ports were acquired. The displacement difference from spinal cord to sternum across the isocenter between coregistered planningmore » Digitally Reconstructed Radiographs (DRRs) and kV imaging of bony thorax is a measure of breath hold reproducibility. The difference between bony coregistration and heart coregistration was the measured heart shift if the patient is aligned to bony anatomy. Results: Percentage of dose reductions from FB to VDIBH: mean heart dose (48%, SD 19%, p = 0.002), mean LAD dose (43%, SD 19%, p = 0.008), and maximum left anterior descending (LAD) dose (60%, SD 22%, p = 0.008). Average breath hold reproducibility using bony anatomy across the isocenter along the anteroposterior (AP) plane from planning to treatment is 1 (range, 0-3; SD, 1) mm. Average heart shifts with respect to bony anatomy between different breath holds are 2 {+-} 3 mm inferior, 1 {+-} 2 mm right, and 1 {+-} 3 mm posterior. Percentage dose changes from planning to delivery: mean heart dose (7%, SD 6%); mean LAD dose, ((9%, SD 7%)S, and maximum LAD dose, (11%, SD 11%) SD 11%, p = 0.008). Conclusion: We observed excellent three-dimensional bony registration between planning and pretreatment imaging. Reduced delivered dose to heart and LAD is maintained throughout VDIBH treatment.« less

Is the Deep Inspiration Breath-Hold Technique Superior to the Free Breathing Technique in Cardiac and Lung Sparing while Treating both Left-Sided Post-Mastectomy Chest Wall and Supraclavicular Regions?

PubMed

Darapu, Anupama; Balakrishnan, Rajesh; Sebastian, Patricia; Hussain, Mohamathu Rafic Kather; Ravindran, Paul; John, Subhashini

2017-01-01

To evaluate the efficacy of the deep inspirational breath-hold (DIBH) technique and its dosimetric advantages over the free breathing (FB) technique in cardiac (heart and left anterior descending artery [LAD]) and ipsilateral lung sparing in left-sided post-mastectomy field-in-field conformal radiotherapy. DIBH is highly reproducible, and this study aims to find out its dosimetric benefits over FB. Nineteen left-sided mastectomy patients were immobilized using breast boards with both arms positioned above the head. All patients had 2 sets of planning CT images (one in FB and another in DIBH) with a Biograph TruePoint HD CT scanner in the same setup. DIBH was performed by tracking the respiratory cycles using a Varian Real-Time Position Management system. The target (chest wall and supraclavicular region), organs at risk (OARs; ipsilateral lung, contralateral lung, heart, LAD, and contralateral breast), and other organs of interests were delineated as per the RTOG (Radiation Therapy Oncology Group) contouring guidelines. The single-isocenter conformal fields in the field treatment plans were generated with the Eclipse Treatment Planning System (Varian Medical Systems) for both FB and DIBH images, and the doses to the target and OARs were compared. The standard fractionation regimen of 50 Gy in 25 fractions over a period of 5 weeks was used for all patients in this study. The target coverage parameters (V95, V105, V107, and D_mean) were found to be 97.8 ± 0.9, 6.1 ± 3.4, 0.2 ± 0.3, and 101.9 ± 0.5% in the FB plans and 98.1 ± 0.8, 6.1 ± 3.2, 0.2 ± 0.3, and 101.9 ± 0.4% in the DIBH plans, respectively. The plan quality indices (conformity index and homogeneity index) also showed 1.3 ± 0.2 and 0.1 for the FB plans and 1.2 ± 0.3 and 0.1 for the DIBH plans, respectively. There was a significant reduction in dose to the heart in the DIBH plans compared to the FB plans, with p values of nearly 0 for the V5, V10, V25, V30, and D_mean dosimetric

A comparative analysis of 3D conformal deep inspiratory–breath hold and free-breathing intensity-modulated radiation therapy for left-sided breast cancer

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

Reardon, Kelli A.; Read, Paul W.; Morris, Monica M.

2013-07-01

Patients undergoing radiation for left-sided breast cancer have increased rates of coronary artery disease. Free-breathing intensity-modulated radiation therapy (FB-IMRT) and 3-dimensional conformal deep inspiratory–breath hold (3D-DIBH) reduce cardiac irradiation. The purpose of this study is to compare the dose to organs at risk in FB-IMRT vs 3D-DIBH for patients with left-sided breast cancer. Ten patients with left-sided breast cancer had 2 computed tomography scans: free breathing and voluntary DIBH. Optimization of the IMRT plan was performed on the free-breathing scan using 6 noncoplanar tangential beams. The 3D-DIBH plan was optimized on the DIBH scan and used standard tangents. Mean volumesmore » of the heart, the left anterior descending coronary artery (LAD), the total lung, and the right breast receiving 5% to 95% (5% increments) of the prescription dose were calculated. Mean volumes of the heart and the LAD were lower (p<0.05) in 3D-DIBH for volumes receiving 5% to 80% of the prescription dose for the heart and 5% for the LAD. Mean dose to the LAD and heart were lower in 3D-DIBH (p≤0.01). Mean volumes of the total lung were lower in FB-IMRT for dose levels 20% to 75% (p<0.05), but mean dose was not different. Mean volumes of the right breast were not different for any dose; however, mean dose was lower for 3D-DIBH (p = 0.04). 3D-DIBH is an alternative approach to FB-IMRT that provides a clinically equivalent treatment for patients with left-sided breast cancer while sparing organs at risk with increased ease of implementation.« less

Attenuation correction of emission PET images with average CT: Interpolation from breath-hold CT

NASA Astrophysics Data System (ADS)

Huang, Tzung-Chi; Zhang, Geoffrey; Chen, Chih-Hao; Yang, Bang-Hung; Wu, Nien-Yun; Wang, Shyh-Jen; Wu, Tung-Hsin

2011-05-01

Misregistration resulting from the difference of temporal resolution in PET and CT scans occur frequently in PET/CT imaging, which causes distortion in tumor quantification in PET. Respiration cine average CT (CACT) for PET attenuation correction has been reported to improve the misalignment effectively by several papers. However, the radiation dose to the patient from a four-dimensional CT scan is relatively high. In this study, we propose a method to interpolate respiratory CT images over a respiratory cycle from inhalation and exhalation breath-hold CT images, and use the average CT from the generated CT set for PET attenuation correction. The radiation dose to the patient is reduced using this method. Six cancer patients of various lesion sites underwent routine free-breath helical CT (HCT), respiration CACT, interpolated average CT (IACT), and 18F-FDG PET. Deformable image registration was used to interpolate the middle phases of a respiratory cycle based on the end-inspiration and end-expiration breath-hold CT scans. The average CT image was calculated from the eight interpolated CT image sets of middle respiratory phases and the two original inspiration and expiration CT images. Then the PET images were reconstructed by these three methods for attenuation correction using HCT, CACT, and IACT. Misalignment of PET image using either CACT or IACT for attenuation correction in PET/CT was improved. The difference in standard uptake value (SUV) from tumor in PET images was most significant between the use of HCT and CACT, while the least significant between the use of CACT and IACT. Besides the similar improvement in tumor quantification compared to the use of CACT, using IACT for PET attenuation correction reduces the radiation dose to the patient.

Optimising diffusion-weighted MR imaging for demonstrating pancreatic cancer: a comparison of respiratory-triggered, free-breathing and breath-hold techniques.

PubMed

Kartalis, Nikolaos; Loizou, Louiza; Edsborg, Nick; Segersvärd, Ralf; Albiin, Nils

2012-10-01

To compare respiratory-triggered, free-breathing, and breath-hold DWI techniques regarding (1) image quality, and (2) signal intensity (SI) and ADC measurements in pancreatic ductal adenocarcinoma (PDAC). Fifteen patients with histopathologically proven PDAC underwent DWI prospectively at 1.5 T (b = 0, 50, 300, 600 and 1,000 s/mm(2)) with the three techniques. Two radiologists, independently and blindly, assigned total image quality scores [sum of rating diffusion images (lesion detection, anatomy, presence of artefacts) and ADC maps (lesion characterisation, overall image quality)] per technique and ranked them. The lesion SI, signal-to-noise ratio, mean ADC and coefficient of variation (CV) were compared. Total image quality scores for respiratory-triggered, free-breathing and breath-hold techniques were 17.9, 16.5 and 17.1 respectively (respiratory-triggered was significantly higher than free-breathing but not breath-hold). The respiratory-triggered technique had a significantly higher ranking. Lesion SI on all b-values and signal-to-noise ratio on b300 and b600 were significantly higher for the respiratory-triggered technique. For respiratory-triggered, free-breathing and breath-hold techniques the mean ADCs were 1.201, 1.132 and 1.253 × 10(-3) mm(2)/s, and mean CVs were 8.9, 10.8 and 14.1 % respectively (respiratory-triggered and free-breathing techniques had a significantly lower mean CV than the breath-hold technique). In both analyses, respiratory-triggered DWI showed superiority and seems the optimal DWI technique for demonstrating PDAC. • Diffusion-weighted magnetic resonance imaging is increasingly used to detect pancreatic cancer • Images are acquired using various breathing techniques and multiple b-values • Breathing techniques used: respiratory-triggering, free-breathing and breath-hold • Respiratory-triggering seems the optimal breathing technique for demonstrating pancreatic cancer.

Breath-hold duration in man and the diving response induced by face immersion.

PubMed

Sterba, J A; Lundgren, C E

1988-09-01

The objective of this study in 5 selected volunteer subjects was to see whether the circulatory diving response which is elicited by breath holding and by cold water on the face would affect the duration of maximal-effort breath holds. Compared to control measurements (breath holding during resting, breathing with 35 degrees C water on the face) breath holding with the face cooled by 20 degrees C water caused a 12% reduction of heart rate, 6% reduction of cardiac output, 33% reduction in [corrected] forearm blood flow, and 9% rise in mean arterial blood pressure, but there was no difference in breath-hold duration (control and experimental both 94 s). There were also no differences in time of appearance of the first involuntary respiratory efforts during breath holding, in alveolar gas exchange, or in breaking-point alveolar O2 and CO2 tensions. When the diving response was magnified by a brief bout of exercise so that there was a 19% [corrected] reduction in heart rate, 23% reduction in cardiac output, and 48% reduction in forearm blood flow, breath-hold duration was still unaffected by face cooling. Compared to intermittent immersions, continuous exposure of the face to cold water abolished the diving response, probably by a cold adaptation of facial thermal receptors. These results with cooling of the face only are consistent with our earlier finding that there was a negative correlation between the duration of a maximal-effort breath hold and the diving response during whole-body submersion in cold water.

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.

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

The effect of CO2 on ventilation and breath-holding during exercise and while breathing through an added resistance.

PubMed

Clark, T J; Godfrey, S

1969-05-01

1. Ventilation was measured while subjects were made to rebreathe from a bag containing CO(2) and O(2) in order to expose them to a steadily rising CO(2) tension (P(CO2)). The object of the experiments was to determine the effect of a variety of stimuli upon the increase in ventilation and fall in breath-holding time which occurs in response to the rising P(CO2).2. Steady-state exercise at 200 kg.m/min resulted in a small fall in the slope of the ventilation-CO(2) response curve (S(V)) and a small, though not statistically significant, fall in the P(CO2) at which ventilation would be zero by extrapolation (B(V)). There was a marked fall in the slope of the breath-holding-CO(2) response curve (S(BH)) and an increase in the P(CO2) at which breath-holding time became zero by extrapolation (B(BH)).3. These results have been interpreted with the aid of a model of the control of breath-holding and it is suggested that there is no change in CO(2) sensitivity on exercise, either during rebreathing or breath-holding.4. An increase in the resistance to breathing caused a marked reduction in S(V) and B(V), but no change in the breath-holding-CO(2) response curve. These findings suggest that the flattening of the ventilation-CO(2) response curve is mechanical in origin and acute airway obstruction produces no change in CO(2) sensitivity.5. On the basis of these results, we suggest that more information about CO(2) sensitivity can be obtained by a combination of ventilation and breath-holding-CO(2) response curves.

Do elite breath-hold divers suffer from mild short-term memory impairments?

PubMed

Billaut, François; Gueit, Patrice; Faure, Sylvane; Costalat, Guillaume; Lemaître, Frédéric

2018-03-01

Repeated apneas are associated with severe hypoxemia that may ultimately lead to loss of consciousness in some breath-hold divers. Despite increasing number of practitioners, the relationship between apnea-induced hypoxia and neurocognitive functions is still poorly understood in the sport of free diving. To shed light onto this phenomenon, we examined the impact of long-term breath-hold diving training on attentional processing, short-term memory, and long-term mnesic and executive functions. Thirty-six men matched for age, height, and weight were separated into the following 3 groups: (i) 12 elite breath-hold divers (EBHD), mean static apnea best time 371 s, 105 months mean apnea experience; (ii) 12 novice breath-hold divers, mean best time 243 s, 8.75 months mean apnea experience; and (iii) 12 physical education students with no breath-hold diving experience; all of these participants performed varied written and computerized neuropsychological tasks. Compared with the 2 other groups, the EBHD group was slower to complete the interference card during a Stroop test (F [1,33] = 4.70, p < 0.05), and presented more errors on the interference card (F [1,33] = 2.96, p < 0.05) and a lower total interference score (F [1,33] = 5.64, p < 0.05). The time to complete the interference card test was positively correlated with maximal static apnea duration (r = 0.73, p < 0.05) and the number of years of breath-hold diving training (r = 0.79, p < 0.001). These findings suggest that breath-hold diving training over several years may cause mild, but persistent, short-term memory impairments.

WE-DE-209-02: Active Breathing Control

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

Comsa, D.

Breast radiation therapy is associated with some risk of lung toxicity as well as cardiac toxicity for left-sided cases. Radiation doses to the lung and heart can be reduced by using the deep inspiration breath hold (DIBH) technique, in which the patient is simulated and treated during the deep inspiration phase of the breathing cycle. During DIBH, the heart is usually displaced posteriorly, inferiorly, and to the right, effectively expanding the distance between the heart and the breast/chest wall. As a result, the distance between the medial treatment field border and heart/lung is increased. Also, in a majority of DIBHmore » patients, the air drawn into the thoracic cavity increases the total lung volume. The DIBH was discussed by an AAPM Task Group 10 years ago in the AAPM TG 76 report. However, DIBH is still not the standard of care in many clinics, which may be partially due to challenges associated with its implementation. Therefore, this seccion will focus primarily on how to clinically implement four different DIBH techniques: (1) Active Breathing Control, (2) Spirometric Motion Management, (3) 3D Surface Image-Guided, and (4) Self-held Breath Control with Respiratory Monitoring and Feedback Guidance. Learning Objectives: Describe the physical displacement of the heart and the change in lung volume during DIBH and discuss dosimetric consequences of those changes. Provide an overview of the technical aspects. Describe work flow for patient simulation and treatment. Give an overview of commissioning and routine. Provide practical tips for clinical implementation.« less

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

Breath-hold device for laboratory rodents undergoing imaging procedures.

PubMed

Rivera, Belinda; Bushman, Mark J; Beaver, Richard G; Cody, Dianna D; Price, Roger E

2006-07-01

The increased use in noninvasive imaging of laboratory rodents has prompted innovative techniques in animal handling. Lung imaging of rodents can be a difficult task because of tissue motion caused by breathing, which affects image quality. The use of a prototype flat-panel computed tomography unit allows the acquisition of images in as little as 2, 4, or 8 s. This short acquisition time has allowed us to improve the image quality of this instrument by performing a breath-hold during image acquisition. We designed an inexpensive and safe method for performing a constant-pressure breath-hold in intubated rodents. Initially a prototypic manual 3-way valve system, consisting of a 3-way valve, an air pressure regulator, and a manometer, was used to manually toggle between the ventilator and the constant-pressure breath-hold equipment. The success of the manual 3-way valve system prompted the design of an electronically actuated valve system. In the electronic system, the manual 3-way valve was replaced with a custom designed 3-way valve operated by an electrical solenoid. The electrical solenoid is triggered by using a hand-held push button or a foot pedal that is several feet away from the gantry of the scanner. This system has provided improved image quality and is safe for the animals, easy to use, and reliable.

Prolonged dry apnoea: effects on brain activity and physiological functions in breath-hold divers and non-divers.

PubMed

Ratmanova, Patricia; Semenyuk, Roxana; Popov, Daniil; Kuznetsov, Sergey; Zelenkova, Irina; Napalkov, Dmitry; Vinogradova, Olga

2016-07-01

The aim of the study was to investigate the effects of voluntary breath-holding on brain activity and physiological functions. We hypothesised that prolonged apnoea would trigger cerebral hypoxia, resulting in a decrease of brain performance; and the apnoea's effects would be more pronounced in breath-hold divers. Trained breath-hold divers and non-divers performed maximal dry breath-holdings. Lung volume, alveolar partial pressures of O2 and CO2, attention and anxiety levels were estimated. Heart rate, blood pressure, arterial blood oxygenation, brain tissue oxygenation, EEG, and DC potential were monitored continuously during breath-holding. There were a few significant changes in electrical brain activity caused by prolonged apnoea. Brain tissue oxygenation index and DC potential were relatively stable up to the end of the apnoea in breath-hold divers and non-divers. We also did not observe any decrease of attention level or speed of processing immediately after breath-holding. Interestingly, trained breath-hold divers had some peculiarities in EEG activity at resting state (before any breath-holding): non-spindled, sharpened alpha rhythm; slowed-down alpha with the frequency nearer to the theta band; and untypical spatial pattern of alpha activity. Our findings contradicted the primary hypothesis. Apnoea up to 5 min does not lead to notable cerebral hypoxia or a decrease of brain performance in either breath-hold divers or non-divers. It seems to be the result of the compensatory mechanisms similar to the diving response aimed at centralising blood circulation and reducing peripheral O2 uptake. Adaptive changes during apnoea are much more prominent in trained breath-hold divers.

3D Late Gadolinium Enhancement in a Single Prolonged Breath-hold using Supplemental Oxygenation and Hyperventilation

PubMed Central

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

2013-01-01

Purpose: To evaluate the feasibility of 3D single breath-hold late gadolinium enhancement (LGE) of the left ventricle (LV) using supplemental oxygen and hyperventilation and compressed-sensing acceleration. Methods: Breath-hold metrics (breath-hold duration, diaphragmatic/LV position drift, and maximum variation of 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 (FOV=320×320×100 mm3, resolution=1.6×1.6×5.0 mm3, acceleration rate of 4) and a free breathing acquisition with right hemidiaphragm navigator (NAV) respiratory gating. Semi-quantitative grading of overall image quality, motion artifact, myocardial nulling, and diagnostic value was performed by consensus of two blinded observers. Results: 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 to free breathing acquisitions but with reduced total scan time (85±22 s to 35±6 s, p<0.001). Conclusions: 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. PMID:24186772

Cardiac Dose Reduction with Deep-Inspiratory Breath Hold Technique of Radiotherapy for Left-Sided Breast Cancer.

PubMed

Sripathi, Lalitha Kameshwari; Ahlawat, Parveen; Simson, David K; Khadanga, Chira Ranjan; Kamarsu, Lakshmipathi; Surana, Shital Kumar; Arasu, Kavi; Singh, Harpreet

2017-01-01

Different techniques of radiation therapy have been studied to reduce the cardiac dose in left breast cancer. In this prospective dosimetric study, the doses to heart as well as other organs at risk (OAR) were compared between free-breathing (FB) and deep inspiratory breath hold (DIBH) techniques in intensity modulated radiotherapy (IMRT) and opposed-tangent three-dimensional radiotherapy (3DCRT) plans. Fifteen patients with left-sided breast cancer underwent computed tomography simulation and images were obtained in both FB and DIBH. Radiotherapy plans were generated with 3DCRT and IMRT techniques in FB and DIBH images in each patient. Target coverage, conformity index, homogeneity index, and mean dose to heart (Heart D mean ), left lung, left anterior descending artery (LAD) and right breast were compared between the four plans using the Wilcoxon signed rank test. Target coverage was adequate with both 3DCRT and IMRT plans, but IMRT plans showed better conformity and homogeneity. A statistically significant dose reduction of all OARs was found with DIBH. 3DCRT DIBH decreased the Heart D mean by 53.5% (7.1 vs. 3.3 Gy) and mean dose to LAD by 28% compared to 3DCRT FB . IMRT further lowered mean LAD dose by 18%. Heart D mean was lower with 3DCRT DIBH over IMRT DIBH (3.3 vs. 10.2 Gy). Mean dose to the contralateral breast was also lower with 3DCRT over IMRT (0.32 vs. 3.35 Gy). Mean dose and the V 20 of ipsilateral lung were lower with 3DCRT DIBH over IMRT DIBH (13.78 vs. 18.9 Gy) and (25.16 vs. 32.95%), respectively. 3DCRT DIBH provided excellent dosimetric results in patients with left-sided breast cancer without the need for IMRT.

Cardiac Dose Reduction with Deep-Inspiratory Breath Hold Technique of Radiotherapy for Left-Sided Breast Cancer

PubMed Central

Sripathi, Lalitha Kameshwari; Ahlawat, Parveen; Simson, David K; Khadanga, Chira Ranjan; Kamarsu, Lakshmipathi; Surana, Shital Kumar; Arasu, Kavi; Singh, Harpreet

2017-01-01

Introduction: Different techniques of radiation therapy have been studied to reduce the cardiac dose in left breast cancer. Aim: In this prospective dosimetric study, the doses to heart as well as other organs at risk (OAR) were compared between free-breathing (FB) and deep inspiratory breath hold (DIBH) techniques in intensity modulated radiotherapy (IMRT) and opposed-tangent three-dimensional radiotherapy (3DCRT) plans. Materials and Methods: Fifteen patients with left-sided breast cancer underwent computed tomography simulation and images were obtained in both FB and DIBH. Radiotherapy plans were generated with 3DCRT and IMRT techniques in FB and DIBH images in each patient. Target coverage, conformity index, homogeneity index, and mean dose to heart (Heart Dmean), left lung, left anterior descending artery (LAD) and right breast were compared between the four plans using the Wilcoxon signed rank test. Results: Target coverage was adequate with both 3DCRT and IMRT plans, but IMRT plans showed better conformity and homogeneity. A statistically significant dose reduction of all OARs was found with DIBH. 3DCRTDIBH decreased the Heart Dmean by 53.5% (7.1 vs. 3.3 Gy) and mean dose to LAD by 28% compared to 3DCRTFB. IMRT further lowered mean LAD dose by 18%. Heart Dmean was lower with 3DCRTDIBH over IMRTDIBH (3.3 vs. 10.2 Gy). Mean dose to the contralateral breast was also lower with 3DCRT over IMRT (0.32 vs. 3.35 Gy). Mean dose and the V20 of ipsilateral lung were lower with 3DCRTDIBH over IMRTDIBH (13.78 vs. 18.9 Gy) and (25.16 vs. 32.95%), respectively. Conclusions: 3DCRTDIBH provided excellent dosimetric results in patients with left-sided breast cancer without the need for IMRT. PMID:28974856

Effects of breathing pattern and inspired air conditions on breath condensate volume, pH, nitrite, and protein concentrations.

PubMed

McCafferty, J B; Bradshaw, T A; Tate, S; Greening, A P; Innes, J A

2004-08-01

The effects of breathing pattern and inspired air conditions on the volume and content of exhaled breath condensate (EBC) were investigated. Total exhaled water (TEW), EBC volume, pH, nitrite and protein concentrations were measured in three groups of 10 healthy subjects breathing into a condenser at different target minute ventilations (Vm), tidal volumes (Vt), and inspired air conditions. The volumes of both TEW and EBC increased significantly with Vm. For Vm 7.5, 15 and 22.5 l/min, mean (SD) EBC was 627 (258) microl, 1019 (313) microl, and 1358 (364) microl, respectively (p<0.001) and TEW was 1879 (378) microl, 2986 (496) microl, and 4679 (700) microl, respectively (p<0.001). TEW was significantly higher than EBC, reflecting a condenser efficiency of 40% at a target Vm of 7.5 l/min which reduced to 29% at Vm 22.5 l/min. Lower Vt gave less TEW than higher Vt (26.6 v 30.7 microl/l, mean difference 4.1 (95% CI 2.6 to 5.6), p<0.001) and a smaller EBC volume (4.3 v 7.6 microl/l, mean difference 3.4 (95% CI 2.3 to 4.5), p<0.001). Cooler and drier inspired air yielded less water vapour and less breath condensate than standard conditions (p<0.05). Changes in the breathing pattern had no effect on EBC protein and nitrite concentrations and pH. These results show that condensate volume can be increased by using high Vt and increased Vm without compromising the dilution of the sample.

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…

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.

The Ins and Outs of Breath Holding: Simple Demonstrations of Complex Respiratory Physiology

ERIC Educational Resources Information Center

Skow, Rachel J.; Day, Trevor A.; Fuller, Jonathan E.; Bruce, Christina D.; Steinback, Craig D.

2015-01-01

The physiology of breath holding is complex, and voluntary breath-hold duration is affected by many factors, including practice, psychology, respiratory chemoreflexes, and lung stretch. In this activity, we outline a number of simple laboratory activities or classroom demonstrations that illustrate the complexity of the integrative physiology…

Optimization of single shot 3D breath-hold non-enhanced MR angiography of the renal arteries.

PubMed

Tan, Huan; Koktzoglou, Ioannis; Glielmi, Christopher; Galizia, Mauricio; Edelman, Robert R

2012-05-19

Cardiac and navigator-gated, inversion-prepared non-enhanced magnetic resonance angiography techniques can accurately depict the renal arteries without the need for contrast administration. However, the scan time and effectiveness of navigator-gated techniques depend on the subject respiratory pattern, which at times results in excessively prolonged scan times or suboptimal image quality. A single-shot 3D magnetization-prepared steady-state free precession technique was implemented to allow the full extent of the renal arteries to be depicted within a single breath-hold. Technical optimization of the breath-hold technique was performed with fourteen healthy volunteers. An alternative magnetization preparation scheme was tested to maximize inflow signal. Quantitative and qualitative comparisons were made between the breath-hold technique and the clinically accepted navigator-gated technique in both volunteers and patients on a 1.5 T scanner. The breath-hold technique provided an average of seven fold reduction in imaging time, without significant loss of image quality. Comparable single-to-noise and contrast-to-noise ratios of intra- and extra-renal arteries were found between the breath-hold and the navigator-gated techniques in volunteers. Furthermore, the breath-hold technique demonstrated good image quality for diagnostic purposes in a small number of patients in a pilot study. The single-shot, breath-hold technique offers an alternative to navigator-gated methods for non-enhanced renal magnetic resonance angiography. The initial results suggest a potential supplementary clinical role for the breath-hold technique in the evaluation of suspected renal artery diseases.

Effects of breathing pattern and inspired air conditions on breath condensate volume, pH, nitrite, and protein concentrations

PubMed Central

McCafferty, J; Bradshaw, T; Tate, S; Greening, A; Innes, J

2004-01-01

Background: The effects of breathing pattern and inspired air conditions on the volume and content of exhaled breath condensate (EBC) were investigated. Methods: Total exhaled water (TEW), EBC volume, pH, nitrite and protein concentrations were measured in three groups of 10 healthy subjects breathing into a condenser at different target minute ventilations (Vm), tidal volumes (Vt), and inspired air conditions. Results: The volumes of both TEW and EBC increased significantly with Vm. For Vm 7.5, 15 and 22.5 l/min, mean (SD) EBC was 627 (258) µl, 1019 (313) µl, and 1358 (364) µl, respectively (p<0.001) and TEW was 1879 (378) µl, 2986 (496) µl, and 4679 (700) µl, respectively (p<0.001). TEW was significantly higher than EBC, reflecting a condenser efficiency of 40% at a target Vm of 7.5 l/min which reduced to 29% at Vm 22.5 l/min. Lower Vt gave less TEW than higher Vt (26.6 v 30.7 µl/l, mean difference 4.1 (95% CI 2.6 to 5.6), p<0.001) and a smaller EBC volume (4.3 v 7.6 µl/l, mean difference 3.4 (95% CI 2.3 to 4.5), p<0.001). Cooler and drier inspired air yielded less water vapour and less breath condensate than standard conditions (p<0.05). Changes in the breathing pattern had no effect on EBC protein and nitrite concentrations and pH. Conclusion: These results show that condensate volume can be increased by using high Vt and increased Vm without compromising the dilution of the sample. PMID:15282391

Optimal technique for deep breathing exercises after cardiac surgery.

PubMed

Westerdahl, E

2015-06-01

Cardiac surgery patients often develop a restrictive pulmonary impairment and gas exchange abnormalities in the early postoperative period. Chest physiotherapy is routinely prescribed in order to reduce or prevent these complications. Besides early mobilization, positioning and shoulder girdle exercises, various breathing exercises have been implemented as a major component of postoperative care. A variety of deep breathing maneuvres are recommended to the spontaneously breathing patient to reduce atelectasis and to improve lung function in the early postoperative period. Different breathing exercises are recommended in different parts of the world, and there is no consensus about the most effective breathing technique after cardiac surgery. Arbitrary instructions are given, and recommendations on performance and duration vary between hospitals. Deep breathing exercises are a major part of this therapy, but scientific evidence for the efficacy has been lacking until recently, and there is a lack of trials describing how postoperative breathing exercises actually should be performed. The purpose of this review is to provide a brief overview of postoperative breathing exercises for patients undergoing cardiac surgery via sternotomy, and to discuss and suggest an optimal technique for the performance of deep breathing exercises.

Affective brain areas and sleep disordered breathing

PubMed Central

Harper, Ronald M.; Kumar, Rajesh; Macey, Paul M.; Woo, Mary A.; Ogren, Jennifer A.

2014-01-01

The neural damage accompanying the hypoxia, reduced perfusion, and other consequences of sleep-disordered breathing found in obstructive sleep apnea, heart failure (HF), and congenital central hypoventilation syndrome (CCHS), appears in areas that serve multiple functions, including emotional drives to breathe, and involve systems that serve affective, cardiovascular, and breathing roles. The damage, assessed with structural magnetic resonance imaging (MRI) procedures, shows tissue loss or water content and diffusion changes indicative of injury, and impaired axonal integrity between structures; damage is preferentially unilateral. Functional MRI responses in affected areas also are time- or amplitude- distorted to ventilatory or autonomic challenges. Among the structures injured are the insular, cingulate, and ventral medial prefrontal cortices, as well as cerebellar deep nuclei and cortex, anterior hypothalamus, raphé, ventrolateral medulla, basal ganglia and, in CCHS, the locus coeruleus. Raphé and locus coeruleus injury may modify serotonergic and adrenergic modulation of upper airway and arousal characteristics. Since both axons and gray matter show injury, the consequences to function, especially to autonomic, cognitive, and mood regulation, are major. Several affected rostral sites, including the insular and cingulate cortices and hippocampus, mediate aspects of dyspnea, especially in CCHS, while others, including the anterior cingulate and thalamus, participate in initiation of inspiration after central breathing pauses, and the medullary injury can impair baroreflex and breathing control. The ancillary injury associated with sleep-disordered breathing to central structures can elicit multiple other distortions in cardiovascular, cognitive, and emotional functions in addition to effects on breathing regulation. PMID:24746053

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.

Comparison of cerebral vascular reactivity measures obtained using breath-holding and CO2 inhalation

PubMed Central

Tancredi, Felipe B; Hoge, Richard D

2013-01-01

Stimulation of cerebral vasculature using hypercapnia has been widely used to study cerebral vascular reactivity (CVR), which can be expressed as the quantitative change in cerebral blood flow (CBF) per mm Hg change in end-tidal partial pressure of CO2 (PETCO2). We investigate whether different respiratory manipulations, with arterial spin labeling used to measure CBF, lead to consistent measures of CVR. The approaches included: (1) an automated system delivering variable concentrations of inspired CO2 for prospective targeting of PETCO2, (2) administration of a fixed concentration of CO2 leading to subject-dependent changes in PETCO2, (3) a breath-hold (BH) paradigm with physiologic modeling of CO2 accumulation, and (4) a maneuver combining breath-hold and hyperventilation. When CVR was expressed as the percent change in CBF per mm Hg change in PETCO2, methods 1 to 3 gave consistent results. The CVR values using method 4 were significantly lower. When CVR was expressed in terms of the absolute change in CBF (mL/100 g per minute per mm Hg), greater discrepancies became apparent: methods 2 and 3 gave lower absolute CVR values compared with method 1, and the value obtained with method 4 was dramatically lower. Our findings indicate that care must be taken to ensure that CVR is measured over the linear range of the CBF-CO2 dose–response curve, avoiding hypocapnic conditions. PMID:23571282

Free-breathing cardiac MR stress perfusion with real-time slice tracking.

PubMed

Basha, Tamer A; Roujol, Sébastien; Kissinger, Kraig V; Goddu, Beth; Berg, Sophie; Manning, Warren J; Nezafat, Reza

2014-09-01

To develop a free-breathing cardiac MR perfusion sequence with slice tracking for use after physical exercise. We propose to use a leading navigator, placed immediately before each 2D slice acquisition, for tracking the respiratory motion and updating the slice location in real-time. The proposed sequence was used to acquire CMR perfusion datasets in 12 healthy adult subjects and 8 patients. Images were compared with the conventional perfusion (i.e., without slice tracking) results from the same subjects. The location and geometry of the myocardium were quantitatively analyzed, and the perfusion signal curves were calculated from both sequences to show the efficacy of the proposed sequence. The proposed sequence was significantly better compared with the conventional perfusion sequence in terms of qualitative image scores. Changes in the myocardial location and geometry decreased by 50% in the slice tracking sequence. Furthermore, the proposed sequence had signal curves that are smoother and less noisy. The proposed sequence significantly reduces the effect of the respiratory motion on the image acquisition in both rest and stress perfusion scans. Copyright © 2013 Wiley Periodicals, Inc.

Fourier modeling of the BOLD response to a breath-hold task: Optimization and reproducibility.

PubMed

Pinto, Joana; Jorge, João; Sousa, Inês; Vilela, Pedro; Figueiredo, Patrícia

2016-07-15

Cerebrovascular reactivity (CVR) reflects the capacity of blood vessels to adjust their caliber in order to maintain a steady supply of brain perfusion, and it may provide a sensitive disease biomarker. Measurement of the blood oxygen level dependent (BOLD) response to a hypercapnia-inducing breath-hold (BH) task has been frequently used to map CVR noninvasively using functional magnetic resonance imaging (fMRI). However, the best modeling approach for the accurate quantification of CVR maps remains an open issue. Here, we compare and optimize Fourier models of the BOLD response to a BH task with a preparatory inspiration, and assess the test-retest reproducibility of the associated CVR measurements, in a group of 10 healthy volunteers studied over two fMRI sessions. Linear combinations of sine-cosine pairs at the BH task frequency and its successive harmonics were added sequentially in a nested models approach, and were compared in terms of the adjusted coefficient of determination and corresponding variance explained (VE) of the BOLD signal, as well as the number of voxels exhibiting significant BOLD responses, the estimated CVR values, and their test-retest reproducibility. The brain average VE increased significantly with the Fourier model order, up to the 3rd order. However, the number of responsive voxels increased significantly only up to the 2nd order, and started to decrease from the 3rd order onwards. Moreover, no significant relative underestimation of CVR values was observed beyond the 2nd order. Hence, the 2nd order model was concluded to be the optimal choice for the studied paradigm. This model also yielded the best test-retest reproducibility results, with intra-subject coefficients of variation of 12 and 16% and an intra-class correlation coefficient of 0.74. In conclusion, our results indicate that a Fourier series set consisting of a sine-cosine pair at the BH task frequency and its two harmonics is a suitable model for BOLD-fMRI CVR measurements

WE-DE-209-05: Self-Held Breath Control with Respiratory Monitoring and Feedback Guidance

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

Gifford, K.

Breast radiation therapy is associated with some risk of lung toxicity as well as cardiac toxicity for left-sided cases. Radiation doses to the lung and heart can be reduced by using the deep inspiration breath hold (DIBH) technique, in which the patient is simulated and treated during the deep inspiration phase of the breathing cycle. During DIBH, the heart is usually displaced posteriorly, inferiorly, and to the right, effectively expanding the distance between the heart and the breast/chest wall. As a result, the distance between the medial treatment field border and heart/lung is increased. Also, in a majority of DIBHmore » patients, the air drawn into the thoracic cavity increases the total lung volume. The DIBH was discussed by an AAPM Task Group 10 years ago in the AAPM TG 76 report. However, DIBH is still not the standard of care in many clinics, which may be partially due to challenges associated with its implementation. Therefore, this seccion will focus primarily on how to clinically implement four different DIBH techniques: (1) Active Breathing Control, (2) Spirometric Motion Management, (3) 3D Surface Image-Guided, and (4) Self-held Breath Control with Respiratory Monitoring and Feedback Guidance. Learning Objectives: Describe the physical displacement of the heart and the change in lung volume during DIBH and discuss dosimetric consequences of those changes. Provide an overview of the technical aspects. Describe work flow for patient simulation and treatment. Give an overview of commissioning and routine. Provide practical tips for clinical implementation.« less

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.

Treatment of Chronic Breath-Holding in an Adult with Severe Mental Retardation: A Clinical Case Study

ERIC Educational Resources Information Center

Reed, Derek D.; Martens, Brian K.

2008-01-01

We describe a clinical case study surrounding the behavioral assessment and operant treatment of, an adult with severe mental retardation who engaged in chronic breath-holding. In this clinical case, previous neurological and medical testing had ruled out biological bases for the individual's breath-holding. A functional behavioral assessment…

Agreement and repeatability of vascular reactivity estimates based on a breath-hold task and a resting state scan

PubMed Central

Lipp, Ilona; Murphy, Kevin; Caseras, Xavier; Wise, Richard G.

2015-01-01

FMRI BOLD responses to changes in neural activity are influenced by the reactivity of the vasculature. By complementing a task-related BOLD acquisition with a vascular reactivity measure obtained through breath-holding or hypercapnia, this unwanted variance can be statistically reduced in the BOLD responses of interest. Recently, it has been suggested that vascular reactivity can also be estimated using a resting state scan. This study aimed to compare three breath-hold based analysis approaches (block design, sine–cosine regressor and CO2 regressor) and a resting state approach (CO2 regressor) to measure vascular reactivity. We tested BOLD variance explained by the model and repeatability of the measures. Fifteen healthy participants underwent a breath-hold task and a resting state scan with end-tidal CO2 being recorded during both. Vascular reactivity was defined as CO2-related BOLD percent signal change/mm Hg change in CO2. Maps and regional vascular reactivity estimates showed high repeatability when the breath-hold task was used. Repeatability and variance explained by the CO2 trace regressor were lower for the resting state data based approach, which resulted in highly variable measures of vascular reactivity. We conclude that breath-hold based vascular reactivity estimations are more repeatable than resting-based estimates, and that there are limitations with replacing breath-hold scans by resting state scans for vascular reactivity assessment. PMID:25795342

Mechanics of airway and alveolar collapse in human breath-hold diving.

PubMed

Fitz-Clarke, John R

2007-11-15

A computational model of the human respiratory tract was developed to study airway and alveolar compression and re-expansion during deep breath-hold dives. The model incorporates the chest wall, supraglottic airway, trachea, branched airway tree, and elastic alveoli assigned time-dependent surfactant properties. Total lung collapse with degassing of all alveoli is predicted to occur around 235 m, much deeper than estimates for aquatic mammals. Hysteresis of the pressure-volume loop increases with maximum diving depth due to progressive alveolar collapse. Reopening of alveoli occurs stochastically as airway pressure overcomes adhesive and compressive forces on ascent. Surface area for gas exchange vanishes at collapse depth, implying that the risk of decompression sickness should reach a plateau beyond this depth. Pulmonary capillary transmural stresses cannot increase after local alveolar collapse. Consolidation of lung parenchyma might provide protection from capillary injury or leakage caused by vascular engorgement due to outward chest wall recoil at extreme depths.

Deep-breathing exercises reduce atelectasis and improve pulmonary function after coronary artery bypass surgery.

PubMed

Westerdahl, Elisabeth; Lindmark, Birgitta; Eriksson, Tomas; Friberg, Orjan; Hedenstierna, Göran; Tenling, Arne

2005-11-01

To investigate the effects of deep-breathing exercises on pulmonary function, atelectasis, and arterial blood gas levels after coronary artery bypass graft (CABG) surgery. In a prospective, randomized trial, patients performing deep-breathing exercises (n = 48) were compared to a control group (n = 42) who performed no breathing exercises postoperatively. Patient management was similar in the groups in terms of assessment, positioning, and mobility. The patients in the deep-breathing group were instructed to perform breathing exercises hourly during daytime for the first 4 postoperative days. The exercises consisted of 30 slow, deep breaths performed with a positive expiratory pressure blow-bottle device (+ 10 cm H(2)O). Spirometric measurements, spiral CT (three transverse levels), arterial blood gas analysis, and scoring of subjective experience of the breathing exercises were performed on the fourth postoperative day. Atelectasis was only half the size in the deep-breathing group compared to the control group, amounting to 2.6 +/- 2.2% vs 4.7 +/- 5.7% (p = 0.045) at the basal level and 0.1 +/- 0.2% vs 0.3 +/- 0.5% (mean +/- SD) [p = 0.01] at the apical level. Compared to the control subjects, the patients in the deep-breathing group had a significantly smaller reduction in FVC (to 71 +/- 12%, vs 64 +/- 13% of the preoperative values; p = 0.01) and FEV(1) (to 71 +/- 11%, vs 65 +/- 13% of the preoperative values; p = 0.01). Arterial oxygen tension, carbon dioxide tension, fever, or length of ICU or hospital stay did not differ between the groups. In the deep-breathing group, 72% of the patients experienced a subjective benefit from the exercises. Patients performing deep-breathing exercises after CABG surgery had significantly smaller atelectatic areas and better pulmonary function on the fourth postoperative day compared to a control group performing no exercises.

Agreement and repeatability of vascular reactivity estimates based on a breath-hold task and a resting state scan.

PubMed

Lipp, Ilona; Murphy, Kevin; Caseras, Xavier; Wise, Richard G

2015-06-01

FMRI BOLD responses to changes in neural activity are influenced by the reactivity of the vasculature. By complementing a task-related BOLD acquisition with a vascular reactivity measure obtained through breath-holding or hypercapnia, this unwanted variance can be statistically reduced in the BOLD responses of interest. Recently, it has been suggested that vascular reactivity can also be estimated using a resting state scan. This study aimed to compare three breath-hold based analysis approaches (block design, sine-cosine regressor and CO2 regressor) and a resting state approach (CO2 regressor) to measure vascular reactivity. We tested BOLD variance explained by the model and repeatability of the measures. Fifteen healthy participants underwent a breath-hold task and a resting state scan with end-tidal CO2 being recorded during both. Vascular reactivity was defined as CO2-related BOLD percent signal change/mmHg change in CO2. Maps and regional vascular reactivity estimates showed high repeatability when the breath-hold task was used. Repeatability and variance explained by the CO2 trace regressor were lower for the resting state data based approach, which resulted in highly variable measures of vascular reactivity. We conclude that breath-hold based vascular reactivity estimations are more repeatable than resting-based estimates, and that there are limitations with replacing breath-hold scans by resting state scans for vascular reactivity assessment. Copyright © 2015. Published by Elsevier Inc.

Influence of forward leaning and incentive spirometry on inspired volumes and inspiratory electromyographic activity during breathing exercises in healthy subjects.

PubMed

Santos, Thalita Vilaboim; Ruas, Gualberto; Sande de Souza, Luciane Aparecida Pascucci; Volpe, Marcia Souza

2012-12-01

Breathing exercises (BE), incentive spirometry and positioning are considered treatment modalities to achieve lung re-expansion. This study evaluated the influence of incentive spirometry and forward leaning on inspired tidal volumes (V(T)) and electromyographic activity of inspiratory muscles during BE. Four modalities of exercises were investigated: deep breathing, spirometry using both flow and volume-oriented devices, and volume-oriented spirometry after modified verbal instruction. Twelve healthy subjects aged 22.7 ± 2.1 years were studied. Surface electromyography activity of diaphragm, external intercostals, sternocleidomastoid and scalenes was recorded. Comparisons among the three types of exercises, without considering spirometry after modified instruction, showed that electromyographic activity and V(T) were lower during volume-oriented spirometry (p = 0.000, p = 0.054, respectively). Forward leaning resulted in a lower V(T) when compared to upright sitting (p = 0.000), but electromyographic activity was not different (p = 0.606). Inspired V(T) and electromyographic activity were higher during volume-oriented spirometry performed after modified instruction when compared with the flow-oriented device (p = 0.027, p = 0.052, respectively). In conclusion BE using volume-oriented spirometry before modified instruction resulted in a lower work of breathing as a result of a lower V(T) and was not a consequence of the device type used. Forward leaning might not be assumed by healthy subjects during situations of augmented respiratory demand. Copyright © 2012 Elsevier Ltd. All rights reserved.

SU-E-J-55: End-To-End Effectiveness Analysis of 3D Surface Image Guided Voluntary Breath-Holding Radiotherapy for Left Breast

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

Lin, M; Feigenberg, S

Purpose To evaluate the effectiveness of using 3D-surface-image to guide breath-holding (BH) left-side breast treatment. Methods Two 3D surface image guided BH procedures were implemented and evaluated: normal-BH, taking BH at a comfortable level, and deep-inspiration-breath-holding (DIBH). A total of 20 patients (10 Normal-BH and 10 DIBH) were recruited. Patients received a BH evaluation using a commercialized 3D-surface- tracking-system (VisionRT, London, UK) to quantify the reproducibility of BH positions prior to CT scan. Tangential 3D/IMRT plans were conducted. Patients were initially setup under free-breathing (FB) condition using the FB surface obtained from the untaged CT to ensure a correct patientmore » position. Patients were then guided to reach the planned BH position using the BH surface obtained from the BH CT. Action-levels were set at each phase of treatment process based on the information provided by the 3D-surface-tracking-system for proper interventions (eliminate/re-setup/ re-coaching). We reviewed the frequency of interventions to evaluate its effectiveness. The FB-CBCT and port-film were utilized to evaluate the accuracy of 3D-surface-guided setups. Results 25% of BH candidates with BH positioning uncertainty > 2mm are eliminated prior to CT scan. For >90% of fractions, based on the setup deltas from3D-surface-trackingsystem, adjustments of patient setup are needed after the initial-setup using laser. 3D-surface-guided-setup accuracy is comparable as CBCT. For the BH guidance, frequency of interventions (a re-coaching/re-setup) is 40%(Normal-BH)/91%(DIBH) of treatments for the first 5-fractions and then drops to 16%(Normal-BH)/46%(DIBH). The necessity of re-setup is highly patient-specific for Normal-BH but highly random among patients for DIBH. Overall, a −0.8±2.4 mm accuracy of the anterior pericardial shadow position was achieved. Conclusion 3D-surface-image technology provides effective intervention to the treatment process and

Dark chocolate reduces endothelial dysfunction after successive breath-hold dives in cool water.

PubMed

Theunissen, Sigrid; Schumacker, Julie; Guerrero, François; Tillmans, Frauke; Boutros, Antoine; Lambrechts, Kate; Mazur, Aleksandra; Pieri, Massimo; Germonpré, Peter; Balestra, Costantino

2013-12-01

The aim of this study is to observe the effects of dark chocolate on endothelial function after a series of successive apnea dives in non-thermoneutral water. Twenty breath-hold divers were divided into two groups: a control group (8 males and 2 females) and a chocolate group (9 males and 1 female). The control group was asked to perform a series of dives to 20 m adding up to 20 min in the quiet diving pool of Conflans-Ste-Honorine (Paris, France), water temperature was 27 °C. The chocolate group performed the dives 1 h after ingestion of 30 g of dark chocolate. Flow-mediated dilatation (FMD), digital photoplethysmography, nitric oxide (NO), and peroxynitrite ONOO−) levels were measured before and after each series of breath-hold dives. A significant decrease in FMD was observed in the control group after the dives (95.28 ± 2.9 % of pre-dive values, p < 0.001) while it was increased in the chocolate group (104.1 ± 2.9 % of pre-dive values, p < 0.01). A decrease in the NO level was observed in the control group (86.76 ± 15.57 %, p < 0.05) whereas no difference was shown in the chocolate group (98.44 ± 31.86 %, p > 0.05). No differences in digital photoplethysmography and peroxynitrites were observed between before and after the dives. Antioxidants contained in dark chocolate scavenge free radicals produced during breath-hold diving. Ingestion of 30 g of dark chocolate 1 h before the dive can thus prevent endothelial dysfunction which can be observed after a series of breath-hold dives.

Reproducibility of The Abdominal and Chest Wall Position by Voluntary Breath-Hold Technique Using a Laser-Based Monitoring and Visual Feedback System

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

Nakamura, Katsumasa; Shioyama, Yoshiyuki; Nomoto, Satoru

2007-05-01

Purpose: The voluntary breath-hold (BH) technique is a simple method to control the respiration-related motion of a tumor during irradiation. However, the abdominal and chest wall position may not be accurately reproduced using the BH technique. The purpose of this study was to examine whether visual feedback can reduce the fluctuation in wall motion during BH using a new respiratory monitoring device. Methods and Materials: We developed a laser-based BH monitoring and visual feedback system. For this study, five healthy volunteers were enrolled. The volunteers, practicing abdominal breathing, performed shallow end-expiration BH (SEBH), shallow end-inspiration BH (SIBH), and deep end-inspirationmore » BH (DIBH) with or without visual feedback. The abdominal and chest wall positions were measured at 80-ms intervals during BHs. Results: The fluctuation in the chest wall position was smaller than that of the abdominal wall position. The reproducibility of the wall position was improved by visual feedback. With a monitoring device, visual feedback reduced the mean deviation of the abdominal wall from 2.1 {+-} 1.3 mm to 1.5 {+-} 0.5 mm, 2.5 {+-} 1.9 mm to 1.1 {+-} 0.4 mm, and 6.6 {+-} 2.4 mm to 2.6 {+-} 1.4 mm in SEBH, SIBH, and DIBH, respectively. Conclusions: Volunteers can perform the BH maneuver in a highly reproducible fashion when informed about the position of the wall, although in the case of DIBH, the deviation in the wall position remained substantial.« less

Breast tumor hemodynamic response during a breath-hold as a biomarker to predict chemotherapeutic efficacy: preclinical study

NASA Astrophysics Data System (ADS)

Lee, Songhyun; Kim, Jae Gwan

2018-04-01

Continuous wave diffuse optical tomographic/spectroscopic system does not provide absolute concentrations of chromophores in tissue and monitor only the changes of chromophore concentration. Therefore, it requires a perturbation of physiological signals, such as blood flow and oxygenation. In that sense, a few groups reported that monitoring a relative hemodynamic change during a breast tissue compression or a breath-hold to a patient can provide good contrast between tumor and nontumor. However, no longitudinal study reports the utilization of a breath-hold to predict tumor response during chemotherapy. A continuous wave near-infrared spectroscopy was employed to monitor hemodynamics in rat breast tumor during a hyperoxic to normoxic inhalational gas intervention to mimic a breath-hold during tumor growth and chemotherapy. The reduced oxyhemoglobin concentration during inhalational gas intervention correlated well with tumor growth, and it responded one day earlier than the change of tumor volume after chemotherapy. In conclusion, monitoring tumor hemodynamics during a breath-hold may serve as a biomarker to predict chemotherapeutic efficacy of tumor.

Reproducibility of lung tumor position and reduction of lung mass within the planning target volume using active breathing control (ABC).

PubMed

Cheung, Patrick C F; Sixel, Katharina E; Tirona, Romeo; Ung, Yee C

2003-12-01

The active breathing control (ABC) device allows for temporary immobilization of respiratory motion by implementing a breath hold at a predefined relative lung volume and air flow direction. The purpose of this study was to quantitatively evaluate the ability of the ABC device to immobilize peripheral lung tumors at a reproducible position, increase total lung volume, and thereby reduce lung mass within the planning target volume (PTV). Ten patients with peripheral non-small-cell lung cancer tumors undergoing radiotherapy had CT scans of their thorax with and without ABC inspiration breath hold during the first 5 days of treatment. Total lung volumes were determined from the CT data sets. Each peripheral lung tumor was contoured by one physician on all CT scans to generate gross tumor volumes (GTVs). The lung density and mass contained within a 1.5-cm PTV margin around each peripheral tumor was calculated using CT numbers. Using the center of the GTV from the Day 1 ABC scan as the reference, the displacement of subsequent GTV centers on Days 2 to 5 for each patient with ABC applied was calculated in three dimensions. With the use of ABC inspiration breath hold, total lung volumes increased by an average of 42%. This resulted in an average decrease in lung mass of 18% within a standard 1.5-cm PTV margin around the GTV. The average (+/- standard deviation) displacement of GTV centers with ABC breath hold applied was 0.3 mm (+/- 1.8 mm), 1.2 mm (+/- 2.3 mm), and 1.1 mm (+/- 3.5 mm) in the lateral direction, anterior-posterior direction, and superior-inferior direction, respectively. Results from this study indicate that there remains some inter-breath hold variability in peripheral lung tumor position with the use of ABC inspiration breath hold, which prevents significant PTV margin reduction. However, lung volumes can significantly increase, thereby decreasing the mass of lung within a standard PTV.

Neurophysiological study on the effect of various short durations of deep breathing: A randomized controlled trial.

PubMed

Cheng, Kok Suen; Han, Ray P S; Lee, Poh Foong

2018-02-01

The study aims to study the effects of short duration deep breathing on the EEG power with topography based on parallel group randomized controlled trial design which was lacking in prior reports. 50 participants were split into 4 groups: control (CONT), deep breathing (DB) for 5 (DB5), 7 (DB7), and 9 (DB9) minutes. EEG recordings were obtained during baseline, deep breathing session, after deep breathing, and a follow-up session after 7 days of consecutive practice. Frontal theta power of DB5 and DB9 was significantly larger than that of CONT after the deep breathing session (p = 0.027 and p = 0.006, respectively) and the profound finding showed that the theta topography obtained a central-focused distribution for DB7 and DB9. The result obtained was consistent with previous literature, albeit for certain deep breathing durations only, indicating a possible linkage between the deep breathing duration and the neurophysiology of the brain. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Sci-Fri PM: Radiation Therapy, Planning, Imaging, and Special Techniques - 11: Quantification of chest wall motion during deep inspiration breast hold treatments using cine EPID images and a physics based algorithm

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

Alpuche Aviles, Jorge E.; VanBeek, Timothy

Purpose: This work presents an algorithm used to quantify intra-fraction motion for patients treated using deep inspiration breath hold (DIBH). The algorithm quantifies the position of the chest wall in breast tangent fields using electronic portal images. Methods: The algorithm assumes that image profiles, taken along a direction perpendicular to the medial border of the field, follow a monotonically and smooth decreasing function. This assumption is invalid in the presence of lung and can be used to calculate chest wall position. The algorithm was validated by determining the position of the chest wall for varying field edge positions in portalmore » images of a thoracic phantom. The algorithm was used to quantify intra-fraction motion in cine images for 7 patients treated with DIBH. Results: Phantom results show that changes in the distance between chest wall and field edge were accurate within 0.1 mm on average. For a fixed field edge, the algorithm calculates the position of the chest wall with a 0.2 mm standard deviation. Intra-fraction motion for DIBH patients was within 1 mm 91.4% of the time and within 1.5 mm 97.9% of the time. The maximum intra-fraction motion was 3.0 mm. Conclusions: A physics based algorithm was developed and can be used to quantify the position of chest wall irradiated in tangent portal images with an accuracy of 0.1 mm and precision of 0.6 mm. Intra-fraction motion for patients treated with DIBH at our clinic is less than 3 mm.« less

EIT based pulsatile impedance monitoring during spontaneous breathing in cystic fibrosis.

PubMed

Krueger-Ziolek, Sabine; Schullcke, Benjamin; Gong, Bo; Müller-Lisse, Ullrich; Moeller, Knut

2017-06-01

Evaluating the lung function in patients with obstructive lung disease by electrical impedance tomography (EIT) usually requires breathing maneuvers containing deep inspirations and forced expirations. Since these maneuvers strongly depend on the patient's co-operation and health status, normal tidal breathing was investigated in an attempt to develop continuous maneuver-free measurements. Ventilation related and pulsatile impedance changes were systematically analyzed during normal tidal breathing in 12 cystic fibrosis (CF) patients and 12 lung-healthy controls (HL). Tidal breaths were subdivided into three inspiratory (In1, In2, In3) and three expiratory (Ex1, Ex2, Ex3) sections of the same amplitude of global impedance change. Maximal changes of the ventilation and the pulsatile impedance signal occurring during these sections were determined (▵I V and ▵I P ). Differences in ▵I V and ▵I P among sections were ascertained in relation to the first inspiratory section. In addition, ▵I V /▵I P was calculated for each section. Medians of changes in ▵I V were  <0.05% in all sections for both subject groups. Both groups showed a similar pattern of ▵I P changes during tidal breathing. Changes in ▵I P first decreased during inspiration (In2), then increased towards the end of inspiration (In3) and reached a maximum at the beginning of expiration (Ex1). During the last two sections of expiration (Ex2, Ex3) ▵I P changes decreased. The CF patients showed higher variations in ▵I P changes compared to the controls (CF:  -426.5%, HL:  -158.1%, coefficient of variation). Furthermore, ▵I V /▵I P significantly differed between expiratory sections for the CF patients (Ex1-Ex2, p  <  0.01; Ex1-Ex3, p  <  0.001; Ex2-Ex3, p  <  0.05), but not for the controls. No significant differences in ▵I V /▵I P between inspiratory sections were determined for both groups. Differences in ▵I P changes and in ▵I V /▵I P between

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.

Double-blind, placebo-controlled trial on the effect of piracetam on breath-holding spells.

PubMed

Sawires, Happy; Botrous, Osama

2012-07-01

Breath-holding spells (BHS) are apparently frightening events occurring in otherwise healthy children.The aim of this study was to evaluate the efficacy of piracetam in the treatment of breath-holding spells. Forty patients with BHS (who were classified into two groups)were involved in a double-blinded placebo-controlled prospective study. Piracetam was given to group A while group B received placebo. Patients were followed monthly for a total period of 4 months. The numbers of attacks/month before and monthly after treatment were documented, and the overall number of attacks/month after treatment was calculated in both groups. The median number of attacks/month before treatment in the two groups was 5.5 and 5,respectively, while after the first month of treatment, it was 2 and 5, respectively. The median overall number of attacks/month after treatment in both groups was 1 and 5, respectively.There was a significant decline of number of attacks after piracetam treatment compared to placebo (p value<0.001). There were no reported side effects of the piracetam throughout the study period. In conclusion, piracetam is a safe and effective drug for the treatment of breath-holding spells in children.

Reflex anoxic seizures ('white breath-holding'): nonepileptic vagal attacks.

PubMed Central

Stephenson, J B

1978-01-01

From clinical history 58 children were diagnosed as having reflex anoxic seizures secondary to provoked cardioinhibition (also known as white breath-holding attacks). Before referral, these seizures were commonly misdiagnosed as epileptic either because the provocation was ignored, not recognised, or was a febrile illness, or because there was no crying, no obvious breath-holding, little cyanosis, and often no pallor to suggest syncope and cerebral ischaemia. The duration of cardiac asystole after ocular compression was measured in these children and in 60 additional children with other paroxysmal disorders. In 45 (78%) of the 58 with reflex anoxic seizures asystole was 2 seconds or over, and in 32 (55%) it was 4 seconds or greater, an abnormal response. Review of the literature supports the concept that these seizures result from vagal-mediated reflex cardiac arrest which can if necessary be prevented by atropine. The simple name 'vagal attack' is proposed. Ocular compression under EEG and ECG control supports the clinical diagnosis if asystole and/or an anoxic seizure is induced; the procedure described is safe and should be routine in seizure or syncope evaluation, when a meticulous history still leaves room for doubt. Images Figs. 1-8 p194-b p194-c p194-d p194-e p194-f p194-g p194-h PMID:348123

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

Breath-hold time during cold water immersion: effects of habituation with psychological training.

PubMed

Barwood, Martin J; Datta, Avijit K; Thelwell, Richard C; Tipton, Michael J

2007-11-01

The loss of the conscious control of respiration on whole body cold water immersion (CWI) can result in the aspiration of water and drowning. Repeated CWI reduces the respiratory drive evoked by CWI and should prolong breath-hold time on CWI (BHmax(CWI)). Psychological skills training (PST) can also increase BHmax(CWI) by improving the ability of individuals to consciously suppress the drive to breathe. This study tested the hypothesis that combining PST and repeated CWI would extend BHmax(CWI) beyond that seen following only repeated CWI. There were 20 male subjects who completed two 2.5-min, head-out breath-hold CWI (BH1 and BH2) in water at 12 degrees C. Following BH1, subjects were matched on BHmax(CWI) and allocated to a habituation (HAB) group or a habituation plus PST group (H+PST). Between BH1 and BH2 both experimental groups undertook five 2.5-min CWI on separate days, during which they breathed freely. The H+PST also received psychological training to help tolerate cold and suppress the drive to breathe on immersion to extend BHmax(CWI). During BH1, mean BHmax(CWI) (+/- SD) in the HAB group was 22.00 (10.33) s and 22.38 (10.65) s in the H+PST. After the five free-breathing CWI, both groups had a longer BHmax(CWI) in BH2. The HAB group improved by 14.13 (20.21) s, an increase of 73%. H+PST improved by 26.86 (24.70) s, a 120% increase. No significant differences were identified between the groups. Habituation significantly increases BHmax on CWI, the addition of PST did not result in statistically significant improvements in BHmax(CWI), but may have practical significance.

Cardiac changes induced by immersion and breath-hold diving in humans.

PubMed

Marabotti, Claudio; Scalzini, Alessandro; Cialoni, Danilo; Passera, Mirko; L'Abbate, Antonio; Bedini, Remo

2009-01-01

To evaluate the separate cardiovascular response to body immersion and increased environmental pressure during diving, 12 healthy male subjects (mean age 35.2 +/- 6.5 yr) underwent two-dimensional Doppler echocardiography in five different conditions: out of water (basal); head-out immersion while breathing (condition A); fully immersed at the surface while breathing (condition B) and breath holding (condition C); and breath-hold diving at 5-m depth (condition D). Heart rate, left ventricular volumes, stroke volume, and cardiac output were obtained by underwater echocardiography. Early (E) and late (A) transmitral flow velocities, their ratio (E/A), and deceleration time of E (DTE) were also obtained from pulsed-wave Doppler, as left ventricular diastolic function indexes. The experimental protocol induced significant reductions in left ventricular volumes, left ventricular stroke volume (P < 0.05), cardiac output (P < 0.001), and heart rate (P < 0.05). A significant increase in E peak (P < 0.01) and E/A (P < 0.01) and a significant reduction of DTE (P < 0.01) were also observed. Changes occurring during diving (condition D) accounted for most of the changes observed in the experimental series. In particular, cardiac output at condition D was significantly lower compared with each of the other experimental conditions, E/A was significantly higher during condition D than in conditions A and C. Finally, DTE was significantly shorter at condition D than in basal and condition C. This study confirms a reduction of cardiac output in diving humans. Since most of the changes were observed during diving, the increased environmental pressure seems responsible for this hemodynamic rearrangement. Left ventricular diastolic function changes suggest a constrictive effect on the heart, possibly accounting for cardiac output reduction.

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

The immediate effects of deep breathing exercises on atelectasis and oxygenation after cardiac surgery.

PubMed

Westerdahl, Elisabeth; Lindmark, Birgitta; Eriksson, Tomas; Hedenstierna, Göran; Tenling, Arne

2003-12-01

Objective--To investigate the effects of deep breathing performed on the second postoperative day after coronary artery bypass graft surgery. Design--The immediate effects of 30 deep breaths performed without a mechanical device (n = 21), with a blow bottle device (n = 20) and with an inspiratory resistance-positive expiratory pressure mask (n = 20) were studied. Spiral computed tomography and arterial blood gas analyses were performed immediately before and after the intervention. Results--Deep breathing caused a significant decrease in atelectatic area from 12.3 +/- 7.3% to 10.2 +/- 6.7% (p < 0.0001) of total lung area 1 cm above the diaphragm and from 3.9 +/- 3.5% to 3.3 +/- 3.1% (p < 0.05) 5 cm above the diaphragm. No difference between the breathing techniques was found. The aerated lung area increased by 5% (p < 0.001). The PaO (2) increased by 0.2 kPa (p < 0.05), while PaCO (2) was unchanged in the three groups. Conclusion--A significant decrease of atelectatic area, increase in aerated lung area and a small increase in PaO (2) were found after performance of 30 deep breaths. No difference between the three breathing techniques was found.

Correlational analysis of electroencephalographic and end-tidal carbon dioxide signals during breath-hold exercise.

PubMed

Morelli, Maria Sole; Vanello, Nicola; Giannoni, Alberto; Frijia, Francesca; Hartwig, Valentina; Maestri, Michelangelo; Bonanni, Enrica; Carnicelli, Luca; Positano, Vincenzo; Passino, Claudio; Emdin, Michele; Landini, Luigi

2015-01-01

The central mechanism of breathing control is not totally understood. Several studies evaluated the correlation between electroencephalographic (EEG) power spectra and respiratory signals by performing resting state tasks or adopting hypercapnic/hypoxic stimuli. The observation of brain activity during voluntary breath hold tasks, might be an useful approach to highlight the areas involved in mechanism of breath regulation. Nevertheless, studies of brain activity with EEG could present some limitations due to presence of severe artifacts. When artifact rejection methods, as independent component analysis, cannot reliably clean EEG data, it is necessary to exclude noisy segments. In this study, global field power in the delta band and end-tidal CO2 were derived from EEG and CO2 signals respectively in 4 healthy subjects during a breath-hold task. The cross correlation function between the two signals was estimated taking into account the presence of missing samples. The statistical significance of the correlation coefficients at different time lags was assessed using surrogate data. Some simulations are introduced to evaluate the effect of missing data on the correlational analysis and their results are discussed. Results obtained on subjects show a significant correlation between changes in EEG power in the delta band and end-tidal CO2. Moreover, the changes in end-tidal CO2 were found to precede those of global field power. These results might help to better understand the cortical mechanisms involved in the control of breathing.

Effects of breathing exercises on breathing patterns in obese and non-obese subjects.

PubMed

Olsén, M F; Lönroth, H; Bake, B

1999-05-01

Chest physiotherapy in connection with abdominal surgery includes different deep-breathing exercises to prevent post-operative pulmonary complications. The therapy is effective in preventing pulmonary complications, especially in high-risk patients such as obese persons. The mechanisms behind the effect is unclear, but part of the effect may be explained by the changes in breathing patterns. The aim of this study was therefore to describe and to analyse the breathing patterns in obese and non-obese subjects during three different breathing techniques frequently used in the treatment of post-operative patients. Twenty-one severely obese [body mass index (BMI) > 40] and 21 non-obese (BMI 19-25) subjects were studied. All persons denied having any lung disease and were non-smokers. The breathing techniques investigated were: deep breaths without any resistance (DB), positive expiratory pressure (PEP) with an airway resistance of approximately +15 cmH2O (1.5 kPa) during expiration, inspiratory resistance positive expiratory pressure (IR-PEP) with a pressure of approximately -10 cmH2O (-1.0 kPa) during inspiration. Expiratory resistance as for PEP. Volume against time was monitored while the subjects were sitting in a body plethysmograph. Variables for volume and flow during the breathing cycle were determined. Tidal volume and alveolar ventilation were highest during DB, and peak inspiratory volume was significantly higher than during PEP and IR-PEP in the group of obese subjects. The breathing cycles were prolonged in all techniques but were most prolonged in PEP and IR-PEP. The functional residual capacity (FRC) was significantly lower during DB than during PEP and IR-PEP in the group of obese subjects. FRC as determined within 2 min of finishing each breathing technique was identical to before the breathing manoeuvres.

The effect of climbing Mount Everest on spleen contraction and increase in hemoglobin concentration during breath holding and exercise.

PubMed

Engan, Harald K; Lodin-Sundström, Angelica; Schagatay, Fanny; Schagatay, Erika

2014-04-01

Release of stored red blood cells resulting from spleen contraction improves human performance in various hypoxic situations. This study determined spleen volume resulting from two contraction-evoking stimuli: breath holding and exercise before and after altitude acclimatization during a Mount Everest ascent (8848 m). Eight climbers performed the following protocol before and after the climb: 5 min ambient air respiration at 1370 m during rest, 20 min oxygen respiration, 20 min ambient air respiration at 1370 m, three maximal-effort breath holds spaced by 2 min, 10 min ambient air respiration, 5 min of cycling at 100 W, and finally 10 min ambient air respiration. We measured spleen volume by ultrasound and capillary hemoglobin (HB) concentration after each exposure, and heart rate (HR) and arterial oxygen saturation (Sao2) continuously. Mean (SD) baseline spleen volume was unchanged at 213 (101) mL before and 206 (52) mL after the climb. Before the climb, spleen volume was reduced to 184 (83) mL after three breath holds, and after the climb three breath holds resulted in a spleen volume of 132 (26) mL (p=0.032). After exercise, the preclimb spleen volume was 186 (89) mL vs. 112 (389) mL) after the climb (p=0.003). Breath hold duration and cardiovascular responses were unchanged after the climb. We concluded that spleen contraction may be enhanced by altitude acclimatization, probably reflecting both the acclimatization to chronic hypoxic exposure and acute hypoxia during physical work.

SU-C-BRF-01: Correlation of DIBH Breath Hold Amplitude with Dosimetric Sparing of Heart and Left Anterior Descending Artery in Left Breast Radiotherapy

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

Kim, Taeho; Reardon, Kelli; Sukovich, Kaitlyn

Purpose: A 7.4% increase in major coronary events per 1 Gy increase in mean heart dose has been reported from the population-based analysis of radiation-induced cardiac toxicity following treatment of left sided breast cancer. Deep inhalation breath-hold (DIBH) is clinically utilized to reduce radiation dose to heart and left anterior descending artery (LAD). We investigated the correlation of dose sparing in heart and LAD with internal DIBH amplitude to develop a quantitative predictive model for expected dose to heart and LAD based on internal breath hold amplitude. Methods: A treatment planning study (Prescription Dose = 50 Gy) was performed onmore » 50 left breast cancer patients underwent DIBH whole breast radiotherapy. Two CT datasets, free breathing (FB) and DIBH, were utilized for treatment planning and for determination of the internal anatomy DIBH amplitude (difference between sternum position at FB and DIBH). The heart and LAD dose between FB and DIBH plans was compared and dose to the heart and LAD as a function of breath hold amplitude was determined. Results: Average DIBH amplitude using internal anatomy was 13.9±4.2 mm. The DIBH amplitude-mean dose reduction correlation is 20%/5mm (0.3 Gy/5mm) for the heart and 18%/5mm (1.1 Gy/5mm) for LAD. The correlation with max dose reduction is 12%/5mm (3.8 Gy/5mm) for the heart and 16%/5mm (3.2 Gy/5mm) for LAD. We found that average dose reductions to LAD from 6.0±6.5 Gy to 2.0±1.6 Gy with DIBH (4.0 Gy reduction: -67%, p < 0.001) and average dose reduction to the heart from 1.3±0.7 Gy to 0.7±0.2 Gy with DIBH (0.6 Gy reduction: -46%, p < 0.001). That suggests using DIBH may reduce the risk of the major coronary event for left sided breast cancer patients. Conclusion: The correlation between breath hold amplitude and dosimetric sparing suggests that dose sparing linearly increases with internal DIBH amplitude.« less

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

Essential Hypertension: Cardiovascular Response to Breath Hold Combined with Exercise.

PubMed

Hoffmann, U; Urban, P; Koschate, J; Drescher, U; Pfister, R; Michels, G

2015-07-01

Essential hypertension (EH) is a widespread disease and might be prevalent in apnea divers and master athletes. Little is known about the influence of EH and the antihypertensive drugs (AHD) on cardiovascular reactions to combined breath hold (BH) and exercise. In this pilot study, healthy divers (HCON) were compared with treated hypertensive divers with regard to heart rate (HR) and mean blood-pressure (MAP) responses to BH, exercise and the combination of both. Ten subjects with EH and ten healthy divers were tested. 3 different 20 s stimuli were applied: BH combined with 30 W or 150 W and 150 W without BH. The time-charts during the stress intervals and during recovery were compared. Subjects treated with an angiotensin-converting enzyme (ACE) inhibitor showed higher changes for MAP values if breath hold was performed. HR responses were obviously changed if a β-blocker was part of the medication. One subject showed extreme MAP responses to all stimuli and conspicuous HR if BH was involved. The modulation of HR-/MAP-response in EH subjects depends on the mechanisms of antihypertensive agents. The combination of an ACE inhibitor and a β-blocker may give the best protection. It is recommended to include short apnea tests in the fitness-to-dive examination to individually predict potential endangerment. © Georg Thieme Verlag KG Stuttgart · New York.

Fine tuning breath-hold-based cerebrovascular reactivity analysis models.

PubMed

van Niftrik, Christiaan Hendrik Bas; Piccirelli, Marco; Bozinov, Oliver; Pangalu, Athina; Valavanis, Antonios; Regli, Luca; Fierstra, Jorn

2016-02-01

We elaborate on existing analysis methods for breath-hold (BH)-derived cerebrovascular reactivity (CVR) measurements and describe novel insights and models toward more exact CVR interpretation. Five blood-oxygen-level-dependent (BOLD) fMRI datasets of neurovascular patients with unilateral hemispheric hemodynamic impairment were used to test various BH CVR analysis methods. Temporal lag (phase), percent BOLD signal change (CVR), and explained variance (coherence) maps were calculated using three different sine models and two novel "Optimal Signal" model-free methods based on the unaffected hemisphere and the sagittal sinus fMRI signal time series, respectively. All models showed significant differences in CVR and coherence between the affected-hemodynamic impaired-and unaffected hemisphere. Voxel-wise phase determination significantly increases CVR (0.60 ± 0.18 vs. 0.82 ± 0.27; P < 0.05). Incorporating different durations of breath hold and resting period in one sine model (two-task) did increase coherence in the unaffected hemisphere, as well as eliminating negative phase commonly obtained by one-task frequency models. The novel model-free "optimal signal" methods both explained the BOLD MR data similar to the two task sine model. Our CVR analysis demonstrates an improved CVR and coherence after implementation of voxel-wise phase and frequency adjustment. The novel "optimal signal" methods provide a robust and feasible alternative to the sine models, as both are model-free and independent of compliance. Here, the sagittal sinus model may be advantageous, as it is independent of hemispheric CVR impairment.

Breath-holding spells may be associated with maturational delay in myelination of brain stem.

PubMed

Vurucu, Sebahattin; Karaoglu, Abdulbaki; Paksu, Sukru M; Oz, Oguzhan; Yaman, Halil; Gulgun, Mustafa; Babacan, Oguzhan; Unay, Bulent; Akin, Ridvan

2014-02-01

To evaluate possible contribution of maturational delay of brain stem in the etiology of breath-holding spells in children using brain stem auditory evoked potentials. The study group included children who experienced breath-holding spells. The control group consisted of healthy age- and sex-matched children. Age, gender, type and frequency of spell, hemoglobin, and ferritin levels in study group and brain stem auditory evoked potentials results in both groups were recorded. Study group was statistically compared with control group for brain stem auditory evoked potentials. The mean age of study and control groups was 26.3 ± 14.6 and 28.9 ± 13.9 months, respectively. The III-V and I-V interpeak latencies were significantly prolonged in the study group compared with the control group (2.07 ± 0.2 milliseconds; 1.92 ± 0.13 milliseconds and 4.00 ± 0.27 milliseconds; 3.83 ± 0.19 milliseconds; P = 0.009 and P = 0.03, respectively). At the same time, III-V and I-V interpeak latencies of patients without anemia in the study group compared with those of control group were significantly prolonged (2.09 ± 0.24 milliseconds; 1.92 ± 0.13 milliseconds and 4.04 ± 0.28 milliseconds; 3.83 ± 0.19 milliseconds; P = 0.007 and P = 0.01, respectively). Our results consider that maturational delay in myelination of brain stem may have a role in the etiology of breath-holding spells in children.

Breath-holding ability of offshore workers inadequate to ensure escape from ditched helicopters.

PubMed

Cheung, S S; D'Eon, N J; Brooks, C J

2001-10-01

Following a helicopter ditching in water, the survival rate of individuals not mortally injured by the impact ranges from 50-85%. One possible cause for this low survival rate is that the crew and passengers cannot hold their breath underwater long enough to make the often difficult escape from an inverted and submerged helicopter. We investigated pulmonary function, breath-holding times in air (BHTa) and water (BHTw) of 228 students enrolled in offshore survival courses required to work in either the offshore petroleum industry or in military marine aviation. Comparisons were performed based on occupation, SCUBA experience, and smoking. In 25 degrees C pool water, the overall BHTw ranged from 5.4 to 120 s with a median of 37 s. Of the 228 subjects, 34% had a BHTw less than the 28 s required for the complete evacuation of a Super Puma helicopter under ideal conditions. No significant differences in BHTw were observed based on either smoking history (Non-Smoker, 41.5 +/- 21.6 s; Smoker, 37.2 +/- 20.2 s) or occupation (Novice, 37.5 +/- 21.1 s; Offshore, 40.5 +/- 21.1 s; Military, 45.2 +/- 20.9 s). However, SCUBA-trained individuals had a significantly longer BHT, (47.4 +/- 21.6 s) than non-SCUBA (37.6 +/- 20.6 s), as well as a greater force vital capacity (FVC), BHTa, and subjective comfort in water. It is concluded that the inability to breath-hold in emergency situations is a major contributor to the low survival rates of marine helicopter ditchings. Therefore, efforts must be made to both decrease escape times and to increase survival time underwater.

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

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.

Retrograde Cerebral Perfusion Results in Better Perfusion to the Striatum Than the Cerebral Cortex During Deep Hypothermic Circulatory Arrest: A Microdialysis Study.

PubMed

Liang, Meng-Ya; Chen, Guang-Xian; Tang, Zhi-Xian; Rong, Jian; Yao, Jian-ping; Wu, Zhong-Kai

2016-03-01

It remains controversial whether contemporary cerebral perfusion techniques, utilized during deep hypothermic circulatory arrest (DHCA), establish adequate perfusion to deep structures in the brain. This study aimed to investigate whether selective antegrade cerebral perfusion (SACP) or retrograde cerebral perfusion (RCP) can provide perfusion equally to various anatomical positions in the brain using metabolic evidence obtained from microdialysis. Eighteen piglets were randomly assigned to 40 min of circulatory arrest (CA) at 18°C without cerebral perfusion (DHCA group, n = 6) or with SACP (SACP group, n = 6) or RCP (RCP group, n = 6). Microdialysis parameters (glucose, lactate, pyruvate, and glutamate) were measured every 30 min in cortex and striatum. After 3 h of reperfusion, brain tissue was harvested for Western blot measurement of α-spectrin. After 40 min of CA, the DHCA group showed marked elevations of lactate and glycerol and a reduction in glucose in the microdialysis perfusate (all P < 0.05). The changes in glucose, lactate, and glycerol in the perfusate and α-spectrin expression in brain tissue were similar between cortex and striatum in the SACP group (all P > 0.05). In the RCP group, the cortex exhibited lower glucose, higher lactate, and higher glycerol in the perfusate and higher α-spectrin expression in brain tissue compared with the striatum (all P < 0.05). Glutamate showed no difference between cortex and striatum in all groups (all P > 0.05). In summary, SACP provided uniform and continuous cerebral perfusion to most anatomical sites in the brain, whereas RCP resulted in less sufficient perfusion to the cortex but better perfusion to the striatum. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Inhomogeneity of pulmonary perfusion during sustained microgravity on SLS-1

NASA Technical Reports Server (NTRS)

Prisk, G. Kim; Guy, Harold J. B.; Elliott, Ann R.; West, John B.

1994-01-01

We studied the effects of gravity on the inhomogeneity of pulmonary perfusion in humans by performing hyperventilation-breath-hold single-breath measurements before, during, and after 9 days of continuous exposure to microgravity during the Spacelab Life Sciences-1 (SLS-1) mission. In microgravity the indicators of inhomogeneity of perfusion, especially the size of cardiogenic oscillations in expired CO2 and the height of phase IV, were markedly reduced. Cardiogenic oscillations were reduced to approximately 60% of their preflight standing size, and the height of phase IV was between 0 and -8% (a terminal fall became a small terminal rise) of the preflight standing value. The terminal change in expired CO2 was nearly abolished in microgravity, indicating more uniformity of blood flow between lung units that close and those that remain open at the end of expiration. A possible explanation of this observation is the disappearance of gravity-dependent topographic inequality of blood flow. The residual cardiogenic oscillations in expired CO2 imply a persisting inhomogeneity of perfusion in the absence of gravity, probably in lung regions that are not within the same acinus.

SU-E-J-211: Design and Study of In-House Software Based Respiratory Motion Monitoring, Controlling and Breath-Hold Device for Gated Radiotherapy

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

Shanmugam, Senthilkumar

Purpose: The purpose of this present work was to fabricate an in-house software based respiratory monitoring, controlling and breath-hold device using computer software programme which guides the patient to have uniform breath hold in response to request during the gated radiotherapy. Methods: The respiratory controlling device consists of a computer, inhouse software, video goggles, a highly sensitive sensor for measurement of distance, mounting systems, a camera, a respiratory signal device, a speaker and a visual indicator. The computer is used to display the respiratory movements of the patient with digital as well as analogue respiration indicators during the respiration cycle,more » to control, breath-hold and analyze the respiratory movement using indigenously developed software. Results: Studies were conducted with anthropomophic phantoms by simulating the respiratory motion on phantoms and recording the respective movements using the respiratory monitoring device. The results show good agreement between the simulated and measured movements. Further studies were conducted for 60 cancer patients with several types of cancers in the thoracic region. The respiratory movement cycles for each fraction of radiotherapy treatment were recorded and compared. Alarm indications are provided in the system to indicate when the patient breathing movement exceeds the threshold level. This will help the patient to maintain uniform breath hold during the radiotherapy treatment. Our preliminary clinical test results indicate that our device is highly reliable and able to maintain the uniform respiratory motion and breathe hold during the entire course of gated radiotherapy treatment. Conclusion: An indigenous respiratory monitoring device to guide the patient to have uniform breath hold device was fabricated. The alarm feature and the visual waveform indicator in the system guide the patient to have normal respiration. The signal from the device can be connected to the

Imaging of cardiac perfusion of free-breathing small animals using dynamic phase-correlated micro-CT

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

Sawall, Stefan; Kuntz, Jan; Socher, Michaela

Purpose:Mouse models of cardiac diseases have proven to be a valuable tool in preclinical research. The high cardiac and respiratory rates of free breathing mice prohibit conventional in vivo cardiac perfusion studies using computed tomography even if gating methods are applied. This makes a sacrification of the animals unavoidable and only allows for the application of ex vivo methods. Methods: To overcome this issue the authors propose a low dose scan protocol and an associated reconstruction algorithm that allows for in vivo imaging of cardiac perfusion and associated processes that are retrospectively synchronized to the respiratory and cardiac motion ofmore » the animal. The scan protocol consists of repetitive injections of contrast media within several consecutive scans while the ECG, respiratory motion, and timestamp of contrast injection are recorded and synchronized to the acquired projections. The iterative reconstruction algorithm employs a six-dimensional edge-preserving filter to provide low-noise, motion artifact-free images of the animal examined using the authors' low dose scan protocol. Results: The reconstructions obtained show that the complete temporal bolus evolution can be visualized and quantified in any desired combination of cardiac and respiratory phase including reperfusion phases. The proposed reconstruction method thereby keeps the administered radiation dose at a minimum and thus reduces metabolic inference to the animal allowing for longitudinal studies. Conclusions: The authors' low dose scan protocol and phase-correlated dynamic reconstruction algorithm allow for an easy and effective way to visualize phase-correlated perfusion processes in routine laboratory studies using free-breathing mice.« less

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

Effects of Slow Deep Breathing at High Altitude on Oxygen Saturation, Pulmonary and Systemic Hemodynamics

PubMed Central

Bilo, Grzegorz; Revera, Miriam; Bussotti, Maurizio; Bonacina, Daniele; Styczkiewicz, Katarzyna; Caldara, Gianluca; Giglio, Alessia; Faini, Andrea; Giuliano, Andrea; Lombardi, Carolina; Kawecka-Jaszcz, Kalina; Mancia, Giuseppe; Agostoni, Piergiuseppe; Parati, Gianfranco

2012-01-01

Slow deep breathing improves blood oxygenation (SpO2) and affects hemodynamics in hypoxic patients. We investigated the ventilatory and hemodynamic effects of slow deep breathing in normal subjects at high altitude. We collected data in healthy lowlanders staying either at 4559 m for 2–3 days (Study A; N = 39) or at 5400 m for 12–16 days (Study B; N = 28). Study variables, including SpO2 and systemic and pulmonary arterial pressure, were assessed before, during and after 15 minutes of breathing at 6 breaths/min. At the end of slow breathing, an increase in SpO2 (Study A: from 80.2±7.7% to 89.5±8.2%; Study B: from 81.0±4.2% to 88.6±4.5; both p<0.001) and significant reductions in systemic and pulmonary arterial pressure occurred. This was associated with increased tidal volume and no changes in minute ventilation or pulmonary CO diffusion. Slow deep breathing improves ventilation efficiency for oxygen as shown by blood oxygenation increase, and it reduces systemic and pulmonary blood pressure at high altitude but does not change pulmonary gas diffusion. PMID:23152851

Effects of slow deep breathing at high altitude on oxygen saturation, pulmonary and systemic hemodynamics.

PubMed

Bilo, Grzegorz; Revera, Miriam; Bussotti, Maurizio; Bonacina, Daniele; Styczkiewicz, Katarzyna; Caldara, Gianluca; Giglio, Alessia; Faini, Andrea; Giuliano, Andrea; Lombardi, Carolina; Kawecka-Jaszcz, Kalina; Mancia, Giuseppe; Agostoni, Piergiuseppe; Parati, Gianfranco

2012-01-01

Slow deep breathing improves blood oxygenation (Sp(O2)) and affects hemodynamics in hypoxic patients. We investigated the ventilatory and hemodynamic effects of slow deep breathing in normal subjects at high altitude. We collected data in healthy lowlanders staying either at 4559 m for 2-3 days (Study A; N = 39) or at 5400 m for 12-16 days (Study B; N = 28). Study variables, including Sp(O2) and systemic and pulmonary arterial pressure, were assessed before, during and after 15 minutes of breathing at 6 breaths/min. At the end of slow breathing, an increase in Sp(O2) (Study A: from 80.2±7.7% to 89.5±8.2%; Study B: from 81.0±4.2% to 88.6±4.5; both p<0.001) and significant reductions in systemic and pulmonary arterial pressure occurred. This was associated with increased tidal volume and no changes in minute ventilation or pulmonary CO diffusion. Slow deep breathing improves ventilation efficiency for oxygen as shown by blood oxygenation increase, and it reduces systemic and pulmonary blood pressure at high altitude but does not change pulmonary gas diffusion.

Motion management within two respiratory-gating windows: feasibility study of dual quasi-breath-hold technique in gated medical procedures

NASA Astrophysics Data System (ADS)

Kim, Taeho; Kim, Siyong; Park, Yang-Kyun; Youn, Kaylin K.; Keall, Paul; Lee, Rena

2014-11-01

A dual quasi-breath-hold (DQBH) technique is proposed for respiratory motion management (a hybrid technique combining breathing-guidance with breath-hold task in the middle). The aim of this study is to test a hypothesis that the DQBH biofeedback system improves both the capability of motion management and delivery efficiency. Fifteen healthy human subjects were recruited for two respiratory motion measurements (free breathing and DQBH biofeedback breathing for 15 min). In this study, the DQBH biofeedback system utilized the abdominal position obtained using an real-time position management (RPM) system (Varian Medical Systems, Palo Alto, USA) to audio-visually guide a human subject for 4 s breath-hold at EOI and 90% EOE (EOE90%) to improve delivery efficiency. We investigated the residual respiratory motion and the delivery efficiency (duty-cycle) of abdominal displacement within the gating window. The improvement of the abdominal motion reproducibility was evaluated in terms of cycle-to-cycle displacement variability, respiratory period and baseline drift. The DQBH biofeedback system improved the abdominal motion management capability compared to that with free breathing. With a phase based gating (mean ± std: 55  ±  5%), the averaged root mean square error (RMSE) of the abdominal displacement in the dual-gating windows decreased from 2.26 mm of free breathing to 1.16 mm of DQBH biofeedback (p-value = 0.007). The averaged RMSE of abdominal displacement over the entire respiratory cycles reduced from 2.23 mm of free breathing to 1.39 mm of DQBH biofeedback breathing in the dual-gating windows (p-value = 0.028). The averaged baseline drift dropped from 0.9 mm min-1 with free breathing to 0.09 mm min-1 with DQBH biofeedback (p-value = 0.048). The averaged duty-cycle with an 1 mm width of displacement bound increased from 15% of free breathing to 26% of DQBH biofeedback (p-value = 0.003). The study demonstrated that the DQBH biofeedback

Clinico-laboratory profile of breath-holding spells in children in Sohag University Hospital, Upper Egypt

PubMed Central

Sadek, Abdelrahim Abdrabou; Mohamed, Montaser Mohamed; Sharaf, El-Zahraa El-Said Ahmed; Magdy, Rofaida Mohamed; Allam, Ahmed Ahmed

2016-01-01

Introduction Breath-holding spells (BHSs) are involuntary pauses of breathing, sometimes accompanied by loss of consciousness. They usually occur in response to an upsetting or surprising situation. Breath-holding spells are usually caused by either a change in the usual breathing pattern or a slowing of the heart rate. In some children, BHSs may be related to iron deficiency anemia. The aim of the work was to study the clinical and laboratory profile of BPHs in children presented to the Neuropediatric Clinic at Sohag University Hospital. Methods An observational prospective study was done at Sohag University Hospital over a period of one year on children diagnosed as having BHSs by clinical history and laboratory evaluation, including complete blood count (CBC), serum iron, serum ferritin, total iron binding capacity, and Electroencephalography (EEG). Results During the period of study (one year), we reviewed data of 32 children who had been diagnosed as having BHSs. We found that cyanotic spells (71.88%) predominated over pallid spells. There were positive family histories (31.25%) and consanguinity (53.135) in the studied patients. We found a high incidence of iron deficiency anemia (62.5%) in association with BHS. Abnormal EEGs were found in (65.63%) of studied children. Conclusion BHS is a common, important problem associated with iron deficiency anemia, which is, in turn, a common nutritional problem in our country. PMID:27279996

Reduction of cardiac and pulmonary complication probabilities after breathing adapted radiotherapy for breast cancer

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

Korreman, Stine S.; Pedersen, Anders N.; Aarup, Lasse Rye

Purpose: Substantial reductions of cardio-pulmonary radiation doses can be achieved using voluntary deep inspiration breath-hold (DIBH) or free breathing inspiration gating (IG) in radiotherapy after conserving surgery for breast cancer. The purpose of this study is to evaluate the radiobiological implications of such dosimetric benefits. Methods and Materials: Patients from previously reported studies were pooled for a total of 33 patients. All patients underwent DIBH and free breathing (FB) scans, and 17 patients underwent an additional IG scan. Tangential conformal treatment plans covering the remaining breast, internal mammary, and periclavicular nodes were optimized for each scan, prescription dose 48 Gy.more » Normal tissue complication probabilities were calculated using the relative seriality model for the heart, and the model proposed by Burman et al. for the lung. Results: Previous computed tomography studies showed that both voluntary DIBH and IG provided reduction of the lung V{sub 5} (relative volume receiving more than 50% of prescription dose) on the order of 30-40%, and a 80-90% reduction of the heart V{sub 5} for left-sided cancers. Corresponding pneumonitis probability of 28.1% (range, 0.7-95.6%) for FB could be reduced to 2.6% (range, 0.1-40.1%) for IG, and 4.3% (range, 0.1-59%) for DIBH. The cardiac mortality probability could be reduced from 4.8% (range, 0.1-23.4%) in FB to 0.5% (range, 0.1-2.6%) for IG and 0.1% (range, 0-3.0%) for DIBH. Conclusions: Remarkable potential is shown for simple voluntary DIBH and free breathing IG to reduce the risk of both cardiac mortality and pneumonitis for the common technique of adjuvant tangential breast irradiation.« less

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.

Permeability Surface of Deep Middle Cerebral Artery Territory on Computed Tomographic Perfusion Predicts Hemorrhagic Transformation After Stroke.

PubMed

Li, Qiao; Gao, Xinyi; Yao, Zhenwei; Feng, Xiaoyuan; He, Huijin; Xue, Jing; Gao, Peiyi; Yang, Lumeng; Cheng, Xin; Chen, Weijian; Yang, Yunjun

2017-09-01

Permeability surface (PS) on computed tomographic perfusion reflects blood-brain barrier permeability and is related to hemorrhagic transformation (HT). HT of deep middle cerebral artery (MCA) territory can occur after recanalization of proximal large-vessel occlusion. We aimed to determine the relationship between HT and PS of deep MCA territory. We retrospectively reviewed 70 consecutive acute ischemic stroke patients presenting with occlusion of the distal internal carotid artery or M1 segment of the MCA. All patients underwent computed tomographic perfusion within 6 hours after symptom onset. Computed tomographic perfusion data were postprocessed to generate maps of different perfusion parameters. Risk factors were identified for increased deep MCA territory PS. Receiver operating characteristic curve analysis was performed to calculate the optimal PS threshold to predict HT of deep MCA territory. Increased PS was associated with HT of deep MCA territory. After adjustments for age, sex, onset time to computed tomographic perfusion, and baseline National Institutes of Health Stroke Scale, poor collateral status (odds ratio, 7.8; 95% confidence interval, 1.67-37.14; P =0.009) and proximal MCA-M1 occlusion (odds ratio, 4.12; 95% confidence interval, 1.03-16.52; P =0.045) were independently associated with increased deep MCA territory PS. Relative PS most accurately predicted HT of deep MCA territory (area under curve, 0.94; optimal threshold, 2.89). Increased PS can predict HT of deep MCA territory after recanalization therapy for cerebral proximal large-vessel occlusion. Proximal MCA-M1 complete occlusion and distal internal carotid artery occlusion in conjunction with poor collaterals elevate deep MCA territory PS. © 2017 American Heart Association, Inc.

Comparison between hyperventilation and breath-holding in panic disorder: patients responsive and non-responsive to both tests.

PubMed

Nardi, Antonio E; Valença, Alexandre M; Mezzasalma, Marco A; Levy, Sandra P; Lopes, Fabiana L; Nascimento, Isabella; Freire, Rafael C; Veras, Andre B; Zin, Walter A

2006-06-15

Our aim was to compare the demographic and psychopathological features of panic disorder (PD) patients who underwent hyperventilation and breath-holding challenge tests, and to describe the features of patients who had a panic attack after both tests versus those patients who did not experience panic after either test. Eighty-five PD patients were induced to hyperventilate (30 breaths/min) for 4 min, and a week later to hold their breath for as long as possible four times with a 2-min interval in between. Anxiety scales were applied before and after the tests. Patients who responded with a panic attack to both tests (BPA, n = 25) were compared with patients who experienced spontaneous panic attacks but did not panic in response to the two tests (NPA, n = 16). The BPA group had a significantly higher presence of respiratory symptoms during a panic attack. The criteria for the respiratory PD subtype were fulfilled in 18 (72.0%) BPA patients and in 6 (37.5%) NPA patients. The BPA patients had a later onset of panic disorder and a higher familial prevalence of PD. Our data suggest that there is a distinction between PD patients who were sensitive to both hyperventilation and breath-holding tests and PD patients who were not affected by the challenge tests. The panic attack may be a final common pathway for different types of stimuli, and respiratory tests may characterize different PD subgroups.

Role of cerebral blood flow in extreme breath holding

PubMed Central

Ainslie, Philip N.; Hoiland, Ryan L.; Willie, Chris K.; MacLeod, David B.; Madden, Dennis; Maslov, Petra Zubin; Drviš, Ivan; Dujić, Željko

2016-01-01

Abstract The role of cerebral blood flow (CBF) on a maximal breath-hold (BH) in ultra-elite divers was examined. Divers (n = 7) performed one control BH, and one BH following oral administration of the non-selective cyclooxygenase inhibitor indomethacin (1.2 mg/kg). Arterial blood gases and CBF were measured prior to (baseline), and at BH termination. Compared to control, indomethacin reduced baseline CBF and cerebral delivery of oxygen (CDO2) by about 26% (p < 0.01). Indomethacin reduced maximal BH time from 339 ± 51 to 319 ± 57 seconds (p = 0.04). In both conditions, the CDO2 remained unchanged from baseline to the termination of apnea. At BH termination, arterial oxygen tension was higher following oral administration of indomethacin compared to control (4.05 ± 0.45 vs. 3.44 ± 0.32 kPa). The absolute increase in CBF from baseline to the termination of apnea was lower with indomethacin (p = 0.01). These findings indicate that the impact of CBF on maximal BH time is likely attributable to its influence on cerebral H+ washout, and therefore central chemoreceptive drive to breathe, rather than to CDO2. PMID:28123816

Role of cerebral blood flow in extreme breath holding.

PubMed

Bain, Anthony R; Ainslie, Philip N; Hoiland, Ryan L; Willie, Chris K; MacLeod, David B; Madden, Dennis; Maslov, Petra Zubin; Drviš, Ivan; Dujić, Željko

2016-01-01

The role of cerebral blood flow (CBF) on a maximal breath-hold (BH) in ultra-elite divers was examined. Divers (n = 7) performed one control BH, and one BH following oral administration of the non-selective cyclooxygenase inhibitor indomethacin (1.2 mg/kg). Arterial blood gases and CBF were measured prior to (baseline), and at BH termination. Compared to control, indomethacin reduced baseline CBF and cerebral delivery of oxygen (CDO 2 ) by about 26% (p < 0.01). Indomethacin reduced maximal BH time from 339 ± 51 to 319 ± 57 seconds (p = 0.04). In both conditions, the CDO 2 remained unchanged from baseline to the termination of apnea. At BH termination, arterial oxygen tension was higher following oral administration of indomethacin compared to control (4.05 ± 0.45 vs. 3.44 ± 0.32 kPa). The absolute increase in CBF from baseline to the termination of apnea was lower with indomethacin (p = 0.01). These findings indicate that the impact of CBF on maximal BH time is likely attributable to its influence on cerebral H + washout, and therefore central chemoreceptive drive to breathe, rather than to CDO 2 .

MO-G-18C-05: Real-Time Prediction in Free-Breathing Perfusion MRI

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

Song, H; Liu, W; Ruan, D

Purpose: The aim is to minimize frame-wise difference errors caused by respiratory motion and eliminate the need for breath-holds in magnetic resonance imaging (MRI) sequences with long acquisitions and repeat times (TRs). The technique is being applied to perfusion MRI using arterial spin labeling (ASL). Methods: Respiratory motion prediction (RMP) using navigator echoes was implemented in ASL. A least-square method was used to extract the respiratory motion information from the 1D navigator. A generalized artificial neutral network (ANN) with three layers was developed to simultaneously predict 10 time points forward in time and correct for respiratory motion during MRI acquisition.more » During the training phase, the parameters of the ANN were optimized to minimize the aggregated prediction error based on acquired navigator data. During realtime prediction, the trained ANN was applied to the most recent estimated displacement trajectory to determine in real-time the amount of spatial Results: The respiratory motion information extracted from the least-square method can accurately represent the navigator profiles, with a normalized chi-square value of 0.037±0.015 across the training phase. During the 60-second training phase, the ANN successfully learned the respiratory motion pattern from the navigator training data. During real-time prediction, the ANN received displacement estimates and predicted the motion in the continuum of a 1.0 s prediction window. The ANN prediction was able to provide corrections for different respiratory states (i.e., inhalation/exhalation) during real-time scanning with a mean absolute error of < 1.8 mm. Conclusion: A new technique enabling free-breathing acquisition during MRI is being developed. A generalized ANN development has demonstrated its efficacy in predicting a continuum of motion profile for volumetric imaging based on navigator inputs. Future work will enhance the robustness of ANN and verify its effectiveness with

First-time imaging of effects of inspired oxygen concentration on regional lung volumes and breathing pattern during hypergravity.

PubMed

Borges, João Batista; Hedenstierna, Göran; Bergman, Jakob S; Amato, Marcelo B P; Avenel, Jacques; Montmerle-Borgdorff, Stéphanie

2015-02-01

Aeroatelectasis can develop in aircrew flying the latest generation high-performance aircraft. Causes alleged are relative hyperoxia, increased gravity in the head-to-foot direction (+Gz), and compression of legs and stomach by anti-G trousers (AGT). We aimed to assess, in real time, the effects of hyperoxia, +Gz accelerations and AGT inflation on changes in regional lung volumes and breathing pattern evaluated in an axial plane by electrical impedance tomography (EIT). The protocol mimicked a routine peacetime flight in combat aircraft. Eight subjects wearing AGT were studied in a human centrifuge during 1 h 15 min exposure of +1 to +3.5Gz. They performed this sequence three times, breathing AIR, 44.5 % O2 or 100 % O2. Continuous recording of functional EIT enabled uninterrupted assessment of regional lung volumes at the 5th intercostal level. Breathing pattern was also monitored. EIT data showed that +3.5Gz, compared with any moment without hypergravity, caused an abrupt decrease in regional tidal volume (VT) and regional end-expiratory lung volume (EELV) measured in the EIT slice, independently of inspired oxygen concentration. Breathing AIR or 44.5 % O2, sub-regional EELV measured in the EIT slice decreased similarly in dorsal and ventral regions, but sub-regional VT measured in the EIT slice decreased significantly more dorsally than ventrally. Breathing 100 % O2, EELV and VT decreased similarly in both regions. Inspired tidal volume increased in hyperoxia, whereas breathing frequency increased in hypergravity and hyperoxia. Our findings suggest that hypergravity and AGT inflation cause airway closure and air trapping in gravity-dependent lung regions, facilitating absorption atelectasis formation, in particular during hyperoxia.

Does smoking abstinence influence distress tolerance? An experimental study comparing the response to a breath-holding test of smokers under tobacco withdrawal and under nicotine replacement therapy.

PubMed

Cosci, Fiammetta; Anna Aldi, Giulia; Nardi, Antonio Egidio

2015-09-30

Distress tolerance has been operationalized as task persistence in stressful behavioral laboratory tasks. According to the distress tolerance perspective, how an individual responds to discomfort/distress predicts early smoking lapses. This theory seems weakly supported by experimental studies since they are limited in number, show inconsistent results, do not include control conditions. We tested the response to a stressful task in smokers under abstinence and under no abstinence to verify if tobacco abstinence reduces task persistence, thus distress tolerance. A placebo-controlled, double-blind, randomized, cross-over design was used. Twenty smokers underwent a breath holding test after the administration of nicotine on one test day and a placebo on another test day. Physiological and psychological variables were assessed at baseline and directly before and after each challenge. Abstinence induced a statistically significant shorter breath holding duration relative to the nicotine condition. No different response to the breath holding test was observed when nicotine and placebo conditions were compared. No response to the breath holding test was found when pre- and post-test values of heart rate, blood pressure, Visual Analogue Scale for fear or discomfort were compared. In brief, tobacco abstinence reduces breath holding duration but breath holding test does not influence discomfort. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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.

Measuring vascular reactivity with resting-state blood oxygenation level-dependent (BOLD) signal fluctuations: A potential alternative to the breath-holding challenge?

PubMed

Jahanian, Hesamoddin; Christen, Thomas; Moseley, Michael E; Pajewski, Nicholas M; Wright, Clinton B; Tamura, Manjula K; Zaharchuk, Greg

2017-07-01

Measurement of the ability of blood vessels to dilate and constrict, known as vascular reactivity, is often performed with breath-holding tasks that transiently raise arterial blood carbon dioxide (P a CO 2 ) levels. However, following the proper commands for a breath-holding experiment may be difficult or impossible for many patients. In this study, we evaluated two approaches for obtaining vascular reactivity information using blood oxygenation level-dependent signal fluctuations obtained from resting-state functional magnetic resonance imaging data: physiological fluctuation regression and coefficient of variation of the resting-state functional magnetic resonance imaging signal. We studied a cohort of 28 older adults (69 ± 7 years) and found that six of them (21%) could not perform the breath-holding protocol, based on an objective comparison with an idealized respiratory waveform. In the subjects that could comply, we found a strong linear correlation between data extracted from spontaneous resting-state functional magnetic resonance imaging signal fluctuations and the blood oxygenation level-dependent percentage signal change during breath-holding challenge ( R 2  = 0.57 and 0.61 for resting-state physiological fluctuation regression and resting-state coefficient of variation methods, respectively). This technique may eliminate the need for subject cooperation, thus allowing the evaluation of vascular reactivity in a wider range of clinical and research conditions in which it may otherwise be impractical.

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.

Chronic daily headache with analgesics overuse in professional women breath-hold divers.

PubMed

Choi, Jay Chol; Lee, Jung Seok; Kang, Sa-Yoon; Kang, Ji-Hoon; Bae, Jong-Myon

2008-07-01

The object of this study is to investigate the prevalence and characteristics of headache in Korean professional women breath-hold divers, including their overuse of analgesics. Headache is a common problem encountered in clinical practice, and undersea divers exhibit unique causes of headache in addition to other common primary headaches. Many scuba divers are known to use various types of drugs to overcome dive-related symptoms or to enhance their underwater performance. The target population of this study was women divers in the northern district of Jeju Island who were registered in the divers' union. Data were collected using telephone interviews with a structured questionnaire. Headache was diagnosed and classified according to criteria of the International Headache Society. Nine hundred and eleven (80.3%) divers responded to the telephone interview. The prevalence rates of headache were 21.4% for tension-type headache and 9.1% for migraine. One hundred and four divers (11.4%) fulfilled the criteria for chronic daily headache (CDH). Overuse of combination analgesics was reported by 70.7% of divers. Women divers with CDH were significantly older and they complained more of tinnitus and dizziness, and had a greater history of hypertension than divers without headache. The prevalence of CDH is high in Korean professional women breath-hold divers, with many of them being combination-analgesics overusers.

Breathing synchronized assessment of the chest hemodynamics: application to gamma and MR angiography

NASA Astrophysics Data System (ADS)

Eclancher, Bernard; Demangeat, Jean-Louis; Germain, Philippe; Baruthio, Joseph

2003-05-01

The project was to assess by gamma and MR angiography the bulk variations of chest blood volume related to deep and slow breathing movements. The acquisitions were performed at constant intervals on the widely moving system, without cardiac gating. Two fast enough modalities were used: a gamma-stethoscope working at 30 msec intervals for bulk volumic detection (of 99Tc labelled red cells), and MR imaging at 0.5 sec intervals well depicting displacements but not yet performing true angiography. The third modality yielding quantitative imaging was the scintillation gamma camera, but which required 30 sec signal acquisitions for each image. Frames were acquired at 1 sec intervals for up to 30 breathing cycles, and later sorted with double (inspiration and expiration) synchronization for the reconstruction of an average breathing cycle. Convergent results were obtained from the three angiographic modalities, confirming that the deep breathing movements produced inspiratory increases in bulk blood volume and caudal-median displacement of heart and great vessels, and expiratory decreases in blood volume and cranial-left displacement of heart and great vessels. Deep and slow breathing contributed effectively to thoracic blood pumping. The design of a 64x64 channels collimator has been undertaken to speed up the scintillation camera imaging acquisitions.

Respiratory motion compensation algorithm of ultrasound hepatic perfusion data acquired in free-breathing

NASA Astrophysics Data System (ADS)

Wu, Kaizhi; Zhang, Xuming; Chen, Guangxie; Weng, Fei; Ding, Mingyue

2013-10-01

Images acquired in free breathing using contrast enhanced ultrasound exhibit a periodic motion that needs to be compensated for if a further accurate quantification of the hepatic perfusion analysis is to be executed. In this work, we present an algorithm to compensate the respiratory motion by effectively combining the PCA (Principal Component Analysis) method and block matching method. The respiratory kinetics of the ultrasound hepatic perfusion image sequences was firstly extracted using the PCA method. Then, the optimal phase of the obtained respiratory kinetics was detected after normalizing the motion amplitude and determining the image subsequences of the original image sequences. The image subsequences were registered by the block matching method using cross-correlation as the similarity. Finally, the motion-compensated contrast images can be acquired by using the position mapping and the algorithm was evaluated by comparing the TICs extracted from the original image sequences and compensated image subsequences. Quantitative comparisons demonstrated that the average fitting error estimated of ROIs (region of interest) was reduced from 10.9278 +/- 6.2756 to 5.1644 +/- 3.3431 after compensating.

Presumed Arterial Gas Embolism After Breath-Hold Diving in Shallow Water.

PubMed

Harmsen, Stefani; Schramm, Dirk; Karenfort, Michael; Christaras, Andreas; Euler, Michael; Mayatepek, Ertan; Tibussek, Daniel

2015-09-01

Dive-related injuries are relatively common, but almost exclusively occur in recreational or scuba diving. We report 2 children with acute central nervous system complications after breath-hold diving. A 12-year-old boy presented with unilateral leg weakness and paresthesia after diving beneath the water surface for a distance of ∼25 m. After ascent, he suddenly felt extreme thoracic pain that resolved spontaneously. Neurologic examination revealed right leg weakness and sensory deficits with a sensory level at T5. Spinal MRI revealed a nonenhancing T2-hyperintense lesion in the central cord at the level of T1/T2 suggesting a spinal cord edema. A few weeks later, a 13-year-old girl was admitted with acute dizziness, personality changes, confusion, and headache. Thirty minutes before, she had practiced diving beneath the water surface for a distance of ∼25 m. After stepping out, she felt sudden severe thoracic pain and lost consciousness. Shortly later she reported headache and vertigo, and numbness of the complete left side of her body. Neurologic examination revealed reduced sensibility to all modalities, a positive Romberg test, and vertigo. Cerebral MRI revealed no pathologic findings. Both children experienced a strikingly similar clinical course. The chronology of events strongly suggests that both patients were suffering from arterial gas embolism. This condition has been reported for the first time to occur in children after breath-hold diving beneath the water surface without glossopharyngeal insufflation. Copyright © 2015 by the American Academy of Pediatrics.

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

Perfusion CT to assess angiogenesis in colon cancer: technical limitations and practical challenges.

PubMed

Dighe, S; Castellano, E; Blake, H; Jeyadevan, N; Koh, M U; Orten, M; Swift, I; Brown, G

2012-10-01

Perfusion CT may have the potential to quantify the degree of angiogenesis of solid tumours in vivo. This study aims to identify the practical and technical challenges inherent to the technique, and evaluate its feasibility in colorectal tumours. 51 patients from 2 institutions prospectively underwent a single perfusion CT on 2 different multidetector scanners. The patients were advised to breath-hold as long as possible, followed by shallow breathing, and were given intravenous buscopan to reduce movement. Numerous steps were explored to identify the challenges. 43 patients successfully completed the perfusion CT as per protocol. Inability to detect the tumour (n=3), misplacement of dynamic sequence co-ordinates (n=2), failure of contrast injection (n=2) and displacement of tumour (n=1) were the reasons for failure. In 14 cases excessive respiratory motion displaced the tumour out of the scanning field along the temporal sequence, leading to erroneous data capture. In nine patients, minor displacements of the tumour were corrected by repositioning the region of interest (ROI) to its original position after reviewing each dynamic sequence slice. In 20 patients the tumour was stable, and data captured from the ROI were representative, and could have been analysed by commercially available Body Tumor Perfusion 3.0® software (GE Healthcare, Waukesha, WI). Hence all data were manually analysed by MATLAB® processing software (MathWorks, Cambridge, UK). Perfusion CT in tumours susceptible to motion during acquisition makes accurate data capture challenging and requires meticulous attention to detail. Motion correction software is essential if perfusion CT is to be used routinely in colorectal cancer.

Breath-hold [68Ga]DOTA-TOC PET/CT in neuroendocrine tumors: detection of additional lesions and effects on quantitative parameters.

PubMed

Zirnsak, Mariana; Bärwolf, Robert; Freesmeyer, Martin

2016-11-08

Respiratory motion during PET/CT acquisition generates artifacts in the form of breath-related blurring, which influences the lesion detectability and diagnostic accuracy. The goal of this study was to verify whether breath-hold [68Ga]DOTA-TOC PET/CT (bhPET) allows detection of additional foci compared to free-breathing PET/CT (fbPET), and to assess the impact of breath-holding on standard uptake values (SUV) and isocontoured volume (Vic40) in patients with neuroendocrine tumors (NET). Patients with NET (n=39) were included in this study. BhPET and fbPET characteristics of 96 lesions were compared, and correlated with standard contrast-enhanced (ce) CT and MRI for lesion verification. Quantitative parameters SUV (max and mean) and Vic40 were assessed for both methods and evaluated by linear regression and Spearman's correlation. The impact of lesion size, localization and time interval between investigations was also analyzed. bhPET identified one additional metastasis not seen at fbPET but visible at ceMRI. Another additional bhPET focus did not have a morphological correlate. At bhPET, the SUVmax and SUVmean proved significantly higher and the Vic40 significantly lower than at fbPET. Lesion size, localization and time intervals did not impact significantly on SUV or Vic40. Currently, routine use of breath-hold [68Ga]DOTA-TOC PET/CT cannot be recommended as only one additional lesion was identified. Therefore, bhPET has currently no indication in patients with NET. If technical improvements regarding PET/CT scanner sensitivity are available, bhPET should be reevaluated in the future.

Effects of forced deep breathing on blood flow velocity in the femoral vein: Developing a new physical prophylaxis for deep vein thrombosis in patients with plaster cast immobilization of the lower limb.

PubMed

Nakanishi, Keisuke; Takahira, Naonobu; Sakamoto, Miki; Yamaoka-Tojo, Minako; Katagiri, Masato; Kitagawa, Jun

2018-02-01

Patients with plaster cast immobilization of the lower limb have an estimated symptomatic venous thromboembolism rate of 5.5%. However, there is currently no practical physical prophylaxis for deep-vein thrombosis (DVT). The objective of this study was to examine the effects of forced deep breathing on peak blood velocity in the superficial femoral vein (PBVFV), which is a surrogate measure of the efficacy of thromboprophylaxis against DVT, in patients with plaster cast immobilization of the lower limb. Nine young males and 18 elderly males were recruited. We immobilized the right lower limb of each subject with a plaster splint and measured PBVFV during forced deep breathing in supine and sitting positions. In all subjects, PBVFV during forced deep breathing in both positions was significantly higher than at rest. There was no significant difference in the PBVFV change ratio for three breathing rates in the sitting position for the young subjects (15breaths/min: 415%, 5breaths/min: 475%, 3breaths/min: 483%), whereas that for the elderly subjects at 3breaths/min (449%) was significantly higher than that at 15breaths/min (284%). Forced deep breathing significantly increased PBVFV in patients with plaster cast immobilization of the lower limb in both supine and sitting positions. Testing the efficacy and adherence in clinical contexts, and following up with the incidence rate of DVT in future studies, is necessary for the development of a new physical prophylaxis for DVT. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improved oxygenation during standing performance of deep breathing exercises with positive expiratory pressure after cardiac surgery: A randomized controlled trial.

PubMed

Pettersson, Henrik; Faager, Gun; Westerdahl, Elisabeth

2015-09-01

Breathing exercises after cardiac surgery are often performed in a sitting position. It is unknown whether oxygenation would be better in the standing position. The aim of this study was to evaluate oxygenation and subjective breathing ability during sitting vs standing performance of deep breathing exercises on the second day after cardiac surgery. Patients undergoing coronary artery bypass grafting (n = 189) were randomized to sitting (controls) or standing. Both groups performed 3 × 10 deep breaths with a positive expiratory pressure device. Peripheral oxygen saturation was measured before, directly after, and 15 min after the intervention. Subjective breathing ability, blood pressure, heart rate, and pain were assessed. Oxygenation improved significantly in the standing group compared with controls directly after the breathing exercises (p < 0.001) and after 15 min rest (p = 0.027). The standing group reported better deep breathing ability compared with controls (p = 0.004). A slightly increased heart rate was found in the standing group (p = 0.047). After cardiac surgery, breathing exercises with positive expiratory pressure, performed in a standing position, significantly improved oxygenation and subjective breathing ability compared with sitting performance. Performance of breathing exercises in the standing position is feasible and could be a valuable treatment for patients with postoperative hypoxaemia.

A randomised crossover trial of the acute effects of a deep-fried Mars bar or porridge on the cerebral vasculature.

PubMed

Dunn, William G; Walters, Matthew R

2014-11-01

The deep-fried Mars bar has been cited as 'all that is wrong with the high-fat, high-sugar Scottish diet'. We investigated the effect of ingestion of a deep-fried Mars bar or porridge on cerebrovascular reactivity. We hypothesised that deep-fried Mars bar ingestion would impair cerebrovascular reactivity, which is associated with increased risk of ischaemic stroke. Twenty-four fasted volunteers were randomised to receive a deep-fried Mars bar and then porridge (control), or vice-versa. We used transcranial Doppler ultrasound to calculate Breath Holding Index as a surrogate measure of cerebrovascular reactivity. Change in Breath Holding Index post-ingestion was the primary outcome measure. Twenty-four healthy adults (mean (SD) age 21.5 (1.7) years, 14 males) completed the protocol. Deep-fried Mars bar ingestion caused a non-significant reduction in cerebrovascular reactivity relative to control (mean difference in absolute Breath Holding Index after deep-fried Mars bar versus porridge -0.11, p = 0.40). Comparison of the difference between the absolute change in Breath Holding Index between genders demonstrated a significant impairment of cerebrovascular reactivity in males (mean difference women minus men of 0.65, 95% CI 0.30 to 1.00, p = 0.0003). Ingestion of a bolus of sugar and fat caused no overall difference in cerebrovascular reactivity, but there was a modest decrease in males. Impaired cerebrovascular reactivity is associated with increased stroke risk, and therefore deep-fried Mars bar ingestion may acutely contribute to cerebral hypoperfusion in men. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Breathing patterns in preterm and term infants immediately after birth.

PubMed

te Pas, Arjan B; Wong, Connie; Kamlin, C Omar F; Dawson, Jennifer A; Morley, Colin J; Davis, Peter G

2009-03-01

There is limited data describing how preterm and term infants breathe spontaneously immediately after birth. We studied spontaneously breathing infants >or=29 wk immediately after birth. Airway flow and tidal volume were measured for 90 s using a hot wire anemometer attached to a facemask. Twelve preterm and 13 term infants had recordings suitable for analysis. The median (interquartile range) proportion of expiratory braking was very high in both groups (preterm 90 [74-99] vs. term 87 [74-94]%; NS). Crying pattern was the predominant breathing pattern for both groups (62 [36-77]% vs. 64 [46-79]%; NS). Preterm infants showed a higher incidence of expiratory hold pattern (9 [4-17]% vs. 2 [0-6]%; p = 0.02). Both groups had large tidal volumes (6.7 [3.9] vs. 6.5 [4.1] mL/kg), high peak inspiratory flows (5.7 [3.8] vs. 8.0 [5] L/min), lower peak expiratory flow (3.6 [2.4] vs. 4.8 [3.2] L/min), short inspiration time (0.31 [0.13] vs. 0.32 [0.16] s) and long expiration time (0.93 [0.64] vs. 1.14 [0.86] s). Directly after birth, both preterm and term infants frequently brake their expiration, mostly by crying. Preterm infants use significantly more expiratory breath holds to defend their lung volume.

MR angiography of the renal artery: comparison of breath-hold two-dimensional phase-contrast cine technique with the phased-array coil and breath-hold two-dimensional time-of-flight technique with the body coil.

PubMed

Masui, T; Takehara, Y; Igarashi, T; Ichijo, K; Takahashi, M; Kaneko, M; Nozaki, A

1997-07-01

Breath-hold 2D phase-contrast (PC) cine MR angiography with a phased-array coil and 2D time-of-flight (TOF) MR angiography were performed in the renal arteries and their findings were compared. Breath-hold 2D thin slice PC and TOF MR angiography were performed in 10 normal volunteers for renal arteries. A PC technique with k-space segmentation was utilized with the phased-array coil. A PC technique provided visualization of the renal artery more distally than a TOF technique (4.8 +/- 0.5 cm vs. 3.7 +/- 0.8 cm). With cardiac triggering, distal renal arteries were well demonstrated in PC MR angiography. On PC images, up- or downward movements of the mid to distal renal arteries with aortic pulsatility were recognized. The quality of the images was better with the PC than with the TOF technique (3.4 vs. 2.7). The mid to distal portions of the renal arteries translationally move with aortic pulsatility. To consistently visualize and evaluate them on MR angiography, cardiac triggering might be required to reduce the effects of pulsatile motions of the renal artery in the use of a phased-array coil.

Can multi-slice or navigator-gated R2* MRI replace single-slice breath-hold acquisition for hepatic iron quantification?

PubMed

Loeffler, Ralf B; McCarville, M Beth; Wagstaff, Anne W; Smeltzer, Matthew P; Krafft, Axel J; Song, Ruitian; Hankins, Jane S; Hillenbrand, Claudia M

2017-01-01

Liver R2* values calculated from multi-gradient echo (mGRE) magnetic resonance images (MRI) are strongly correlated with hepatic iron concentration (HIC) as shown in several independently derived biopsy calibration studies. These calibrations were established for axial single-slice breath-hold imaging at the location of the portal vein. Scanning in multi-slice mode makes the exam more efficient, since whole-liver coverage can be achieved with two breath-holds and the optimal slice can be selected afterward. Navigator echoes remove the need for breath-holds and allow use in sedated patients. To evaluate if the existing biopsy calibrations can be applied to multi-slice and navigator-controlled mGRE imaging in children with hepatic iron overload, by testing if there is a bias-free correlation between single-slice R2* and multi-slice or multi-slice navigator controlled R2*. This study included MRI data from 71 patients with transfusional iron overload, who received an MRI exam to estimate HIC using gradient echo sequences. Patient scans contained 2 or 3 of the following imaging methods used for analysis: single-slice images (n = 71), multi-slice images (n = 69) and navigator-controlled images (n = 17). Small and large blood corrected region of interests were selected on axial images of the liver to obtain R2* values for all data sets. Bland-Altman and linear regression analysis were used to compare R2* values from single-slice images to those of multi-slice images and navigator-controlled images. Bland-Altman analysis showed that all imaging method comparisons were strongly associated with each other and had high correlation coefficients (0.98 ≤ r ≤ 1.00) with P-values ≤0.0001. Linear regression yielded slopes that were close to 1. We found that navigator-gated or breath-held multi-slice R2* MRI for HIC determination measures R2* values comparable to the biopsy-validated single-slice, single breath-hold scan. We conclude that these three R2

Ventilation-perfusion distribution in normal subjects.

PubMed

Beck, Kenneth C; Johnson, Bruce D; Olson, Thomas P; Wilson, Theodore A

2012-09-01

Functional values of LogSD of the ventilation distribution (σ(V)) have been reported previously, but functional values of LogSD of the perfusion distribution (σ(q)) and the coefficient of correlation between ventilation and perfusion (ρ) have not been measured in humans. Here, we report values for σ(V), σ(q), and ρ obtained from wash-in data for three gases, helium and two soluble gases, acetylene and dimethyl ether. Normal subjects inspired gas containing the test gases, and the concentrations of the gases at end-expiration during the first 10 breaths were measured with the subjects at rest and at increasing levels of exercise. The regional distribution of ventilation and perfusion was described by a bivariate log-normal distribution with parameters σ(V), σ(q), and ρ, and these parameters were evaluated by matching the values of expired gas concentrations calculated for this distribution to the measured values. Values of cardiac output and LogSD ventilation/perfusion (Va/Q) were obtained. At rest, σ(q) is high (1.08 ± 0.12). With the onset of ventilation, σ(q) decreases to 0.85 ± 0.09 but remains higher than σ(V) (0.43 ± 0.09) at all exercise levels. Rho increases to 0.87 ± 0.07, and the value of LogSD Va/Q for light and moderate exercise is primarily the result of the difference between the magnitudes of σ(q) and σ(V). With known values for the parameters, the bivariate distribution describes the comprehensive distribution of ventilation and perfusion that underlies the distribution of the Va/Q ratio.

Bronchodilatory effect of deep inspiration in freshly isolated sheep lungs.

PubMed

Wong, William D; Wang, Lu; Paré, Peter D; Seow, Chun Y

2017-02-01

Taking a big breath is known to reverse bronchoconstriction induced by bronchochallenge in healthy subjects; this bronchodilatory effect of deep inspiration (DI) is diminished in asthmatics. The mechanism underlying the DI effect is not clear. Observations from experiments using isolated airway smooth muscle (ASM) preparations and airway segments suggest that straining of ASM due to DI could lead to bronchodilation, possibly due to strain-induced reduction in ASM contractility. However, factors external to the lung cannot be excluded as potential causes for the DI effect. Neural reflex initiated by stretch receptors in the lung are known to inhibit the broncho-motor tone and enhance vasodilatation; the former directly reduces airway resistance, and the latter facilitates removal of contractile agonists through the bronchial circulation. If the DI effect is solely mediated by factors extrinsic to the lung, the DI effect would be absent in isolated, nonperfused lungs. Here we examined the DI effect in freshly isolated, nonperfused sheep lungs. We found that imposition of DI on isolated lungs resulted in significant bronchodilation, that this DI effect was present only after the lungs were challenged with a contractile agonist (acetylcholine or histamine), and that the effect was independent of the difference in lung volume observed pre- and post-DI. We conclude that a significant portion of the bronchodilatory DI effect stems from factors internal to the lung related to the activation of ASM. Copyright © 2017 the American Physiological Society.

Gestation increases the energetic cost of breathing in the lizard Tiliqua rugosa.

PubMed

Munns, Suzanne L

2013-01-15

High gestational loads result in fetuses that occupy a large proportion of the body cavity and may compress maternal organs. Compression of the lungs results in alterations in breathing patterns during gestation, which may affect the energetic cost of breathing. In this study, the energetic cost of breathing during gestation was determined in the viviparous skink Tiliqua rugosa. Radiographic imaging showed progressive lung compression during gestation and a 30% reduction in the lung inflation index (rib number at which the caudal margin of the lung was imaged divided by total rib number). Pneumotachography and open flow respirometry were used to measure breathing patterns and metabolic rates. Gestation induced a twofold increase in minute ventilation via increases in breathing frequency, but no change in inspired tidal volume. The rates of O(2) consumption and CO(2) production did not change significantly during gestation. Together, these results suggest that a relative hyperventilation occurs during gestation in T. rugosa, which in turn suggests that diffusion and/or perfusion limitations may exist at the lung during gestation. The energetic cost of breathing was estimated as a percentage of resting metabolic rate using hypercapnia to stimulate ventilation at different stages of pregnancy. The energetic cost of breathing in non-pregnant lizards was 19.96±3.85% of resting metabolic rate and increased threefold to 62.80±10.11% during late gestation. This significant increase in the energetic cost of breathing may have significant consequences for energy budgets during gestation.

Robustness of the Voluntary Breath-Hold Approach for the Treatment of Peripheral Lung Tumors Using Hypofractionated Pencil Beam Scanning Proton Therapy

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

Dueck, Jenny, E-mail: jenny.dueck@psi.ch; Center for Proton Therapy, Paul Scherrer Institut, Villigen PSI; Niels Bohr Institute, University of Copenhagen, Copenhagen

Purpose: The safe clinical implementation of pencil beam scanning (PBS) proton therapy for lung tumors is complicated by the delivery uncertainties caused by breathing motion. The purpose of this feasibility study was to investigate whether a voluntary breath-hold technique could limit the delivery uncertainties resulting from interfractional motion. Methods and Materials: Data from 15 patients with peripheral lung tumors previously treated with stereotactic radiation therapy were included in this study. The patients had 1 computed tomographic (CT) scan in voluntary breath-hold acquired before treatment and 3 scans during the treatment course. PBS proton treatment plans with 2 fields (2F) andmore » 3 fields (3F), respectively, were calculated based on the planning CT scan and subsequently recalculated on the 3 repeated CT scans. Recalculated plans were considered robust if the V{sub 95%} (volume receiving ≥95% of the prescribed dose) of the gross target volume (GTV) was within 5% of what was expected from the planning CT data throughout the simulated treatment. Results: A total of 14/15 simulated treatments for both 2F and 3F met the robustness criteria. Reduced V{sub 95%} was associated with baseline shifts (2F, P=.056; 3F, P=.008) and tumor size (2F, P=.025; 3F, P=.025). Smaller tumors with large baseline shifts were also at risk for reduced V{sub 95%} (interaction term baseline/size: 2F, P=.005; 3F, P=.002). Conclusions: The breath-hold approach is a realistic clinical option for treating lung tumors with PBS proton therapy. Potential risk factors for reduced V{sub 95%} are small targets in combination with large baseline shifts. On the basis of these results, the baseline shift of the tumor should be monitored (eg, through image guided therapy), and appropriate measures should be taken accordingly. The intrafractional motion needs to be investigated to confirm that the breath-hold approach is robust.« less

All puffed out: do pufferfish hold their breath while inflated?

PubMed Central

McGee, Georgia Evelyn; Clark, Timothy Darren

2014-01-01

The inflation response of pufferfishes is one of the most iconic predator defence strategies in nature. Current dogma suggests that pufferfish inflation represents a breath-holding response, whereby gill oxygen uptake ceases for the duration of inflation and cutaneous respiration increases to compensate. Here, we show that the black-saddled pufferfish (Canthigaster valentini) has an excellent capacity for oxygen uptake while inflated, with uptake rates increasing to five-times that of resting levels. Moreover, we show that this species has negligible capacity for cutaneous respiration, concluding that the gills are the primary site of oxygen uptake while inflated. Despite this, post-deflation recovery of aerobic metabolism took an average of 5.6 h, suggesting a contribution of anaerobic metabolism during pre-inflation activity and during the act of ingesting water to achieve inflation. PMID:25472941

Markerless positional verification using template matching and triangulation of kV images acquired during irradiation for lung tumors treated in breath-hold

NASA Astrophysics Data System (ADS)

Hazelaar, Colien; Dahele, Max; Mostafavi, Hassan; van der Weide, Lineke; Slotman, Ben; Verbakel, Wilko

2018-06-01

Lung tumors treated in breath-hold are subject to inter- and intra-breath-hold variations, which makes tumor position monitoring during each breath-hold important. A markerless technique is desirable, but limited tumor visibility on kV images makes this challenging. We evaluated if template matching  +  triangulation of kV projection images acquired during breath-hold stereotactic treatments could determine 3D tumor position. Band-pass filtering and/or digital tomosynthesis (DTS) were used as image pre-filtering/enhancement techniques. On-board kV images continuously acquired during volumetric modulated arc irradiation of (i) a 3D-printed anthropomorphic thorax phantom with three lung tumors (n  =  6 stationary datasets, n  =  2 gradually moving), and (ii) four patients (13 datasets) were analyzed. 2D reference templates (filtered DRRs) were created from planning CT data. Normalized cross-correlation was used for 2D matching between templates and pre-filtered/enhanced kV images. For 3D verification, each registration was triangulated with multiple previous registrations. Generally applicable image processing/algorithm settings for lung tumors in breath-hold were identified. For the stationary phantom, the interquartile range of the 3D position vector was on average 0.25 mm for 12° DTS  +  band-pass filtering (average detected positions in 2D  =  99.7%, 3D  =  96.1%, and 3D excluding first 12° due to triangulation angle  =  99.9%) compared to 0.81 mm for band-pass filtering only (55.8/52.9/55.0%). For the moving phantom, RMS errors for the lateral/longitudinal/vertical direction after 12° DTS  +  band-pass filtering were 1.5/0.4/1.1 mm and 2.2/0.3/3.2 mm. For the clinical data, 2D position was determined for at least 93% of each dataset and 3D position excluding first 12° for at least 82% of each dataset using 12° DTS  +  band-pass filtering. Template matching�

Determination of ethane, pentane and isoprene in exhaled air--effects of breath-holding, flow rate and purified air.

PubMed

Lärstad, M A E; Torén, K; Bake, B; Olin, A-C

2007-01-01

Exhaled ethane, pentane and isoprene have been proposed as biomarkers of oxidative stress. The objectives were to explore whether ethane, pentane and isoprene are produced within the airways and to explore the effect of different sampling parameters on analyte concentrations. The flow dependency of the analyte concentrations, the concentrations in dead-space and alveolar air after breath-holding and the influence of inhaling purified air on analyte concentrations were investigated. The analytical method involved thermal desorption from sorbent tubes and gas chromatography. The studied group comprised 13 subjects with clinically stable asthma and 14 healthy controls. Ethane concentrations decreased slightly, but significantly, at higher flow rates in subjects with asthma (P = 0.0063) but not in healthy controls. Pentane levels were increased at higher flow rates both in healthy and asthmatic subjects (P = 0.022 and 0.0063 respectively). Isoprene levels were increased at higher flow rates, but only significantly in healthy subjects (P = 0.0034). After breath-holding, no significant changes in ethane levels were observed. Pentane and isoprene levels increased significantly after 20 s of breath-holding. Inhalation of purified air before exhalation resulted in a substantial decrease in ethane levels, a moderate decrease in pentane levels and an increase in isoprene levels. The major fractions of exhaled ethane, pentane and isoprene seem to be of systemic origin. There was, however, a tendency for ethane to be flow rate dependent in asthmatic subjects, although to a very limited extent, suggesting that small amounts of ethane may be formed in the airways.

Noninvasive quantification of left-to-right shunt by phase contrast magnetic resonance imaging in secundum atrial septal defect: the effects of breath holding and comparison with invasive oximetry.

PubMed

Yamasaki, Yuzo; Kawanami, Satoshi; Kamitani, Takeshi; Sagiyama, Koji; Sakamoto, Ichiro; Hiasa, Ken-Ichi; Yabuuchi, Hidetake; Nagao, Michinobu; Honda, Hiroshi

2018-01-16

To investigate the effect of breath-holding on left-to-right shunts in patients with a secundum atrial septal defect (ASD). Thirty-five consecutive patients with secundum ASDs underwent right heart catheterization and invasive oximetry. Phase-contrast magnetic resonance imaging (MRI) was performed for the main pulmonary artery and ascending aorta. All measurements were obtained during free breathing (FB) (quiet breathing; no breath-hold), expiratory breath-hold (EBH), and inspiratory breath-hold (IBH). Pulmonary circulation flow (Qp) and systemic circulation flow (Qs) were calculated by multiplying the heart rate by the stroke volume. Measurements during FB, EBH, and IBH were compared, and the differences compared to invasive oximetry were evaluated. There were significant differences among the measurements during FB, EBH, and IBH for Qp (FB, 7.70 ± 2.68; EBH, 7.18 ± 2.34; IBH, 6.88 ± 2.51 l/min); however, no significant difference was found for Qs (FB, 3.44 ± 0.74; EBH, 3.40 ± 0.83; IBH, 3.40 ± 0.86 l/min). There were significant differences among the measurements during FB, EBH, and IBH for Qp/Qs (FB, 2.38 ± 1.12; EBH, 2.24 ± 0.95; IBH, 2.14 ± 0.97). Qp/Qs during FB and EBH correlated better with Qp/Qs measured by invasive oximetry than did IBH. The limit of agreement was smaller for EBH than for FB and IBH. In patients with secundum ASDs, Qp/Qs significantly decreased with breath-holding. The accuracy of the Qp/Qs measurement by MRI compared with invasive oximetry during EBH was higher than during FB and IBH.

Submaximal exercise with self-contained breathing apparatus: the effects of hyperoxia and inspired gas density.

PubMed

Eves, Neil D; Petersen, Stewart R; Jones, Richard L

2003-10-01

The self-contained breathing apparatus (SCBA) used by firefighters, and other working in dangerous environments, adds an external resistance to expiration, which increases expiratory work during heavy exercise. Compressed air is typically used with the SCBA and we hypothesized that changing the inspired oxygen concentration and/or gas density with helium would reduce the external expiratory resistance. On separate days, 15 men completed four 30-min bouts of treadmill exercise dressed in protective clothing and breathing the test gases through the SCBA. Four different gas mixtures were assigned in random order: [compressed air (NOX: 21% O2, 79% N2), hyperoxia (HOX: 40% O2, 60% N2), normoxic-helium (HE-OX: 21% O2, 79% He), and helium-hyperoxia (HE-HOX: 40% O2, 60% He)]. Compared with NOX, the two helium mixtures (but not HOX), decreased the external breathing resistance and all three gas mixtures decreased the peak expired mask pressure and the ventilatory mass moved. Both hyperoxic mixtures decreased blood lactate and the rating of perceived exertion was decreased at 30 min with HE-HOX. These results demonstrate that the helium-based gas mixtures, and to a lesser extent HOX, reduce the expiratory work associated with the SCBA during strenuous exercise.

Selective cerebral perfusion prevents abnormalities in glutamate cycling and neuronal apoptosis in a model of infant deep hypothermic circulatory arrest and reperfusion.

PubMed

Kajimoto, Masaki; Ledee, Dolena R; Olson, Aaron K; Isern, Nancy G; Robillard-Frayne, Isabelle; Des Rosiers, Christine; Portman, Michael A

2016-11-01

Deep hypothermic circulatory arrest is often required for the repair of complex congenital cardiac defects in infants. However, deep hypothermic circulatory arrest induces neuroapoptosis associated with later development of neurocognitive abnormalities. Selective cerebral perfusion theoretically provides superior neural protection possibly through modifications in cerebral substrate oxidation and closely integrated glutamate cycling. We tested the hypothesis that selective cerebral perfusion modulates glucose utilization, and ameliorates abnormalities in glutamate flux, which occur in association with neuroapoptosis during deep hypothermic circulatory arrest. Eighteen infant male Yorkshire piglets were assigned randomly to two groups of seven (deep hypothermic circulatory arrest or deep hypothermic circulatory arrest with selective cerebral perfusion for 60 minutes at 18℃) and four control pigs without cardiopulmonary bypass support. Carbon-13-labeled glucose as a metabolic tracer was infused, and gas chromatography-mass spectrometry and nuclear magnetic resonance were used for metabolic analysis in the frontal cortex. Following 2.5 h of cerebral reperfusion, we observed similar cerebral adenosine triphosphate levels, absolute levels of lactate and citric acid cycle intermediates, and carbon-13 enrichment among three groups. However, deep hypothermic circulatory arrest induced significant abnormalities in glutamate cycling resulting in reduced glutamate/glutamine and elevated γ-aminobutyric acid/glutamate along with neuroapoptosis, which were all prevented by selective cerebral perfusion. The data suggest that selective cerebral perfusion prevents these modifications in glutamate/glutamine/γ-aminobutyric acid cycling and protects the cerebral cortex from apoptosis. © The Author(s) 2016.

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

Deep breathing exercises with positive expiratory pressure at a higher rate improve oxygenation in the early period after cardiac surgery--a randomised controlled trial.

PubMed

Urell, Charlotte; Emtner, Margareta; Hedenström, Hans; Tenling, Arne; Breidenskog, Marie; Westerdahl, Elisabeth

2011-07-01

In addition to early mobilisation, a variety of breathing exercises are used to prevent postoperative pulmonary complications after cardiac surgery. The optimal duration of the treatment is not well evaluated. The aim of this study was to determine the effect of 30 versus 10 deep breaths hourly, while awake, with positive expiratory pressure on oxygenation and pulmonary function the first days after cardiac surgery. A total of 181 patients, undergoing cardiac surgery, were randomised into a treatment group, performing 30 deep breaths hourly the first postoperative days, or into a control group performing 10 deep breaths hourly. The main outcome measurement arterial blood gases and the secondary outcome pulmonary function, evaluated with spirometry, were determined on the second postoperative day. Preoperatively, both study groups were similar in terms of age, SpO(2), forced expiratory volume in 1s and New York Heart Association classification. On the second postoperative day, arterial oxygen tension (PaO(2)) was 8.9 ± 1.7 kPa in the treatment group and 8.1 ± 1.4 kPa in the control group (p = 0.004). Arterial oxygen saturation (SaO(2)) was 92.7 ± 3.7% in the treatment group and 91.1 ± 3.8% in the control group (p = 0.016). There were no differences in measured lung function between the groups or in compliance to the breathing exercises. Compliance was 65% of possible breathing sessions. A significantly increased oxygenation was found in patients performing 30 deep breaths the first two postoperative days compared with control patients performing 10 deep breaths hourly. These results support the implementation of a higher rate of deep breathing exercises in the initial phase after cardiac surgery. Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Magnetic Resonance Imaging of Ventilation and Perfusion in the Lung

NASA Technical Reports Server (NTRS)

Prisk, Gordon Kim (Inventor); Hopkins, Susan Roberta (Inventor); Pereira De Sa, Rui Carlos (Inventor); Theilmann, Rebecca Jean (Inventor); Buxton, Richard Bruce (Inventor); Cronin, Matthew Vincent (Inventor)

2017-01-01

Methods, devices, and systems are disclosed for implementing a fully quantitative non-injectable contrast proton MRI technique to measure spatial ventilation-perfusion (VA/Q) matching and spatial distribution of ventilation and perfusion. In one aspect, a method using MRI to characterize ventilation and perfusion in a lung includes acquiring an MR image of the lung having MR data in a voxel and obtaining a breathing frequency parameter, determining a water density value, a specific ventilation value, and a perfusion value in at least one voxel of the MR image based on the MR data and using the water density value to determine an air content value, and determining a ventilation-perfusion ratio value that is the product of the specific ventilation value, the air content value, the inverse of the perfusion value, and the breathing frequency.

Moderate correlation between breath-holding and CO(2) inhalation/hyperventilation methods for transcranial doppler evaluation of cerebral vasoreactivity.

PubMed

Haussen, Diogo C; Katsnelson, Michael; Rodriguez, Abiezer; Campo, Nelly; Campo-Bustillo, Iszet; Romano, Jose G; Koch, Sebastian

2012-01-01

Both CO(2) inhalation followed by hyperventilation and breath-holding have been utilized to measure cerebral vasomotor reactivity (VMR) but their correlation has been poorly studied and understood. A retrospective study was conducted in 143 subjects (62.6 ± 15.8 years old, 64% men) with transcranial Doppler ultrasonography measurement of mean flow velocity (MFV) at baseline, after 30 seconds of breath-holding, and after CO(2) inhalation followed by hyperventilation, in the left and right middle cerebral artery. Breath-holding index (BHI) was calculated as the percentage of MFV increase from baseline per second of apnea. CO(2) inhalation/hyperventilation index (CO(2) /HV) was calculated as the percentage of MFV difference between CO(2) inhalation and hyperventilation. There were 75 carotid arteries with >70% stenosis or occlusion, and 18 middle cerebral arteries with >50% stenosis or occlusion. The mean BHI was 0.93 ± 0.7 and 0.89 ± 0.6, whereas the mean CO(2) /HV was 61 ± 26% and 60 ± 26%, respectively, on the right and left sides. The correlation between BHI and CO(2) /HV was moderate on the right (r = 0.33; p < 0.01) and left sides (r = 0.38; p < 0.01). Multivariate linear regression analysis indicated that age (p = 0.01) and history of stroke (p = 0.007) were associated independently with an impaired VMR on the right as measured by CO(2) /HV. No predictors for impaired VMR by CO(2) /HV on the left and by BHI on either side were found. CO(2) /HV and BHI are only moderately correlated. Further studies are necessary to determine which method more accurately predicts clinical morbidity. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound 2012; Published online in Wiley Online Library. Copyright © 2012 Wiley Periodicals, Inc.

Poster - Thur Eve - 26: Interfraction reproducibility of heart position during breast irradiation using Active Breathing Control.

PubMed

Comsa, D; Zhang, B; Mosely, D; Yeung, I

2012-07-01

The moderate deep-inspiration breath hold (mDIBH) technique using the Active Breathing Coordinator (ABC) from Elekta is used in our clinic to lower the heart dose during left breast irradiations. The purpose of this work was to investigate the interfraction reproducibility of the heart to chest distance during these treatments and to evaluate the dosimetric effect of any changes in the heart position. Daily CBCT images were available for 5 patients who had been treated with ABC tangents and a cavity boost. On these images, one-dimensional measurements of the distance between the heart and the chest wall were taken at two anatomical locations corresponding roughly with the location where the radiation field most likely intercepts the heart. The average change in this distance was interpreted as a shift of the heart position. To assess the effect of this shift on the delivered heart dose, the heart contours in the clinical plans of the corresponding patients were shifted towards the treatment field using standard Pinnacle tools. Although the ABC device allows good reproducibility of the volume of air held, this does not warrant reproducibility of heart position for all patients during treatment. The largest average heart shift extracted from CBCT images in this study was 6.2mm. The heart dose reconstructed using this shift for the corresponding patient also showed the largest effect. However, even in the presence of a systematic heart shift of this magnitude, the ABC plan still showed superior heart dose reduction compared to the free-breathing plan. © 2012 American Association of Physicists in Medicine.

Respiratory motion prediction and prospective correction for free-breathing arterial spin-labeled perfusion MRI of the kidneys.

PubMed

Song, Hao; Ruan, Dan; Liu, Wenyang; Stenger, V Andrew; Pohmann, Rolf; Fernández-Seara, Maria A; Nair, Tejas; Jung, Sungkyu; Luo, Jingqin; Motai, Yuichi; Ma, Jingfei; Hazle, John D; Gach, H Michael

2017-03-01

Respiratory motion prediction using an artificial neural network (ANN) was integrated with pseudocontinuous arterial spin labeling (pCASL) MRI to allow free-breathing perfusion measurements in the kidney. In this study, we evaluated the performance of the ANN to accurately predict the location of the kidneys during image acquisition. A pencil-beam navigator was integrated with a pCASL sequence to measure lung/diaphragm motion during ANN training and the pCASL transit delay. The ANN algorithm ran concurrently in the background to predict organ location during the 0.7-s 15-slice acquisition based on the navigator data. The predictions were supplied to the pulse sequence to prospectively adjust the axial slice acquisition to match the predicted organ location. Additional navigators were acquired immediately after the multislice acquisition to assess the performance and accuracy of the ANN. The technique was tested in eight healthy volunteers. The root-mean-square error (RMSE) and mean absolute error (MAE) for the eight volunteers were 1.91 ± 0.17 mm and 1.43 ± 0.17 mm, respectively, for the ANN. The RMSE increased with transit delay. The MAE typically increased from the first to last prediction in the image acquisition. The overshoot was 23.58% ± 3.05% using the target prediction accuracy of ± 1 mm. Respiratory motion prediction with prospective motion correction was successfully demonstrated for free-breathing perfusion MRI of the kidney. The method serves as an alternative to multiple breathholds and requires minimal effort from the patient. © 2017 American Association of Physicists in Medicine.

Assessment of regional ventilation and deformation using 4D-CT imaging for healthy human lungs during tidal breathing

PubMed Central

Jahani, Nariman; Choi, Jiwoong; Iyer, Krishna; Hoffman, Eric A.

2015-01-01

This study aims to assess regional ventilation, nonlinearity, and hysteresis of human lungs during dynamic breathing via image registration of four-dimensional computed tomography (4D-CT) scans. Six healthy adult humans were studied by spiral multidetector-row CT during controlled tidal breathing as well as during total lung capacity and functional residual capacity breath holds. Static images were utilized to contrast static vs. dynamic (deep vs. tidal) breathing. A rolling-seal piston system was employed to maintain consistent tidal breathing during 4D-CT spiral image acquisition, providing required between-breath consistency for physiologically meaningful reconstructed respiratory motion. Registration-derived variables including local air volume and anisotropic deformation index (ADI, an indicator of preferential deformation in response to local force) were employed to assess regional ventilation and lung deformation. Lobar distributions of air volume change during tidal breathing were correlated with those of deep breathing (R2 ≈ 0.84). Small discrepancies between tidal and deep breathing were shown to be likely due to different distributions of air volume change in the left and the right lungs. We also demonstrated an asymmetric characteristic of flow rate between inhalation and exhalation. With ADI, we were able to quantify nonlinearity and hysteresis of lung deformation that can only be captured in dynamic images. Nonlinearity quantified by ADI is greater during inhalation, and it is stronger in the lower lobes (P < 0.05). Lung hysteresis estimated by the difference of ADI between inhalation and exhalation is more significant in the right lungs than that in the left lungs. PMID:26316512

Proof of Concept to Isolate and Culture Primary Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-hold Diving

DTIC Science & Technology

2013-09-30

Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-hold Diving...Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-hold Diving 5a...two day period in September, 2012. The first major huddle to the study was to determine the effect of the overnight shipping of the viability of

Proof of Concept to Isolate and Culture Primary Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-Hold Diving

DTIC Science & Technology

2014-09-30

that are too small have less effective results with mechanical trituration that follows digestion). 5. Move dish and sample into the cell culture...Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-Hold Diving...Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-Hold Diving 5a

SU-F-J-22: Lung VolumeVariability Assessed by Bh-CBCT in 3D Surface Image Guided Deep InspirationBreath Hold (DIBH) Radiotherapy for Left-Sided Breast Cancer

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

Gutierrez, A; Stanley, D; Papanikolaou, N

Purpose: With the increasing use of DIBH techniques for left-sided breast cancer, 3D surface-image guided DIBH techniques have improved patient setup and facilitated DIBH radiation delivery. However, quantification of the daily separation between the heart and left breast still presents a challenge. One method of assuring separation is to ensure consistent left lung filling. With this in mind, the aim of this study is to retrospectively quantify left lung volume from weekly breath hold-CBCTs (bh-CBCT) of left-sided breast patients treated using a 3D surface imaging system. Methods: Ten patients (n=10) previously treated to the left breast using the C-Rad CatalystHDmore » system (C-RAD AG, Uppsala Sweden) were evaluated. Patients were positioned with CatalystHD and with bh-CBCT. bh-CBCTs were acquired at the validation date, first day of treatment and at subsequent weekly intervals. Total treatment courses spanned from 3 to 5 weeks. bh-CBCT images were exported to VelocityAI and the left lung volume was segmented. Volumes were recorded and analyzed. Results: A total of 41 bh-CBCTs were contoured in VelocityAI for the 10 patients. The mean left lung volume for all patients was 1657±295cc based on validation bh-CBCT. With the subsequent lung volumes normalized to the validation lung volume, the mean relative ratios for all patients were 1.02±0.11, 0.97±0.14, 0.98±0.11, 1.02±0.01, and 0.96±0.02 for week 1, 2, 3, 4, and 5, respectively. Overall, the mean left lung volume change was ≤4.0% over a 5-week course; however left lung volume variations of up to 28% were noted in a select patient. Conclusion: With the use of the C-RAD CatalystHD system, the mean lung volume variability over a 5-week course of DIBH treatments was ≤4.0%. By minimizing left lung volume variability, heart to left breast separation maybe more consistently maintained. AN Gutierrez has a research grant from C-RAD AG.« less

Deep Learning for Prediction of Obstructive Disease From Fast Myocardial Perfusion SPECT: A Multicenter Study.

PubMed

Betancur, Julian; Commandeur, Frederic; Motlagh, Mahsaw; Sharir, Tali; Einstein, Andrew J; Bokhari, Sabahat; Fish, Mathews B; Ruddy, Terrence D; Kaufmann, Philipp; Sinusas, Albert J; Miller, Edward J; Bateman, Timothy M; Dorbala, Sharmila; Di Carli, Marcelo; Germano, Guido; Otaki, Yuka; Tamarappoo, Balaji K; Dey, Damini; Berman, Daniel S; Slomka, Piotr J

2018-03-12

The study evaluated the automatic prediction of obstructive disease from myocardial perfusion imaging (MPI) by deep learning as compared with total perfusion deficit (TPD). Deep convolutional neural networks trained with a large multicenter population may provide improved prediction of per-patient and per-vessel coronary artery disease from single-photon emission computed tomography MPI. A total of 1,638 patients (67% men) without known coronary artery disease, undergoing stress 99m Tc-sestamibi or tetrofosmin MPI with new generation solid-state scanners in 9 different sites, with invasive coronary angiography performed within 6 months of MPI, were studied. Obstructive disease was defined as ≥70% narrowing of coronary arteries (≥50% for left main artery). Left ventricular myocardium was segmented using clinical nuclear cardiology software and verified by an expert reader. Stress TPD was computed using sex- and camera-specific normal limits. Deep learning was trained using raw and quantitative polar maps and evaluated for prediction of obstructive stenosis in a stratified 10-fold cross-validation procedure. A total of 1,018 (62%) patients and 1,797 of 4,914 (37%) arteries had obstructive disease. Area under the receiver-operating characteristic curve for disease prediction by deep learning was higher than for TPD (per patient: 0.80 vs. 0.78; per vessel: 0.76 vs. 0.73: p < 0.01). With deep learning threshold set to the same specificity as TPD, per-patient sensitivity improved from 79.8% (TPD) to 82.3% (deep learning) (p < 0.05), and per-vessel sensitivity improved from 64.4% (TPD) to 69.8% (deep learning) (p < 0.01). Deep learning has the potential to improve automatic interpretation of MPI as compared with current clinical methods. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. 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.

A better state-of-mind: deep breathing reduces state anxiety and enhances test performance through regulating test cognitions in children.

PubMed

Khng, Kiat Hui

2017-11-01

A pre-test/post-test, intervention-versus-control experimental design was used to examine the effects, mechanisms and moderators of deep breathing on state anxiety and test performance in 122 Primary 5 students. Taking deep breaths before a timed math test significantly reduced self-reported feelings of anxiety and improved test performance. There was a statistical trend towards greater effectiveness in reducing state anxiety for boys compared to girls, and in enhancing test performance for students with higher autonomic reactivity in test-like situations. The latter moderation was significant when comparing high-versus-low autonomic reactivity groups. Mediation analyses suggest that deep breathing reduces state anxiety in test-like situations, creating a better state-of-mind by enhancing the regulation of adaptive-maladaptive thoughts during the test, allowing for better performance. The quick and simple technique can be easily learnt and effectively applied by most children to immediately alleviate some of the adverse effects of test anxiety on psychological well-being and academic performance.

A simple test of one minute heart rate variability during deep breathing for evaluation of sympatovagal imbalance in hyperthyroidism.

PubMed

Shuvy, Mony; Arbelle, Jonathan E; Grosbard, Aviva; Katz, Amos

2008-01-01

Heart rate variability is a sensitive marker of cardiac sympathetic activity. To determine whether long-term hyperthyroidism induced by thyroxine suppressive therapy affects HRV. Nineteen patients treated with suppressive doses of thyroxin for thyroid cancer and 19 age-matched controls were enrolled. Thyroid function tests and 1 minute HRV were performed on all subjects and the results were compared between the groups. The 1 minute HRV was analyzed during deep breathing and defined as the difference in beats/minute between the shortest and the longest heart rate interval measured by eletrocardiographic recording during six cycles of deep breathing. One minute HRV during deep breathing was significantly lower among thyroxine-treated patients compared to healthy controls (25.6 +/- 10.5 vs. 34.3 +/- 12.6 beats/min, P < 0.05). There were no significant differences in mean, maximal and minimal heart rate between the groups. Thyroxine therapy administered for epithelial thyroid cancer resulted in subclinical hyperthyroidism and significantly decreased HRV due to autonomic dysfunction rather than basic elevated heart rate.

Laughter is not always funny: breath-holding spells in familial dysautonomia.

PubMed

Maayan, Channa; Katz, Eliot; Begin, Michal; Yuvchev, Ivelin; Kharasch, Virginia S

2015-02-01

Familial dysautonomia (FD) is a genetic disease characterized by primary autonomic dysfunction including parasympathetic hypersensitivity. Breath-holding spells (BHS) are believed to be caused by autonomic dysregulation mediated via the vagus nerve and increased in patients with a family history of BHS. Details and understanding of its pathophysiology are lacking. In this retrospective study of patients with FD, the incidence of BHS was higher at 53.3%, compared with previous studies in normal children. Laughter as a precipitating factor for BHS has not been previously reported in FD and occurred in 10% of patients in this study. Lower lung volumes, chronic lung disease, chronic CO2 retention, and inadequate autonomic compensation occur in those with FD leading to a higher incidence and severity of BHS when crying or laughing. Thus, FD may be a good model for understanding manifestations of the autonomic nervous system dysfunction and contribute to our knowledge of BHS mechanisms. © The Author(s) 2014.

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

Enhanced conflict monitoring via a short-duration, video-assisted deep breathing in healthy young adults: an event-related potential approach through the Go/NoGo paradigm.

PubMed

Cheng, Kok Suen; Chang, Yun Fah; Han, Ray P S; Lee, Poh Foong

2017-01-01

Practitioners of mindfulness are reported to have greater cognitive control especially in conflict monitoring, response inhibition and sustained attention. However, due to the various existing methods in each mindfulness practices and also, the high commitment factor, a barrier still exists for an individual to pick up the practices. Therefore, the effect of short duration deep breathing on the cognitive control is investigated here. Short duration guided deep breathing videos consisting of 5, 7 and 9 min respectively were created and used on subjects training. The effect on cognitive control was assessed using a Go/NoGo task along with event-related potential (ERP) measurements at Fz, Cz, and Pz. From the study, the significant outcome showed at the follow-up session in which participants engaged for 5 min deep breathing group showed a profound NoGo N2 amplitude increment as compared to the control group, indicating an enhanced conflict monitoring ability. An inverse relationship between the NoGo N2 amplitude and the breathing duration is observed as well at the follow-up session. These results indicated the possibility of performing short duration deep breathing guided by a video to achieve an enhanced conflict monitoring as an alternative to other mindfulness practices and 5 min is found to be the optimum practice duration. This study is the first to establish a relationship between deep breathing and conflict monitoring through ERP. The study population of young adults taken from the same environment reduces the variance in ERP results due to age and environment. A larger sample size would provide a greater statistical power. A longer duration of deep breathing should be investigated to further clarify the relationship between the practice duration and the NoGo N2 amplitude. The result can be split by gender and analyzed separately due to the different brain structure of males and females.

Evaluation of Free Breathing Versus Breath Hold Diffusion Weighted Imaging in Terms Apparent Diffusion Coefficient (ADC) and Signal-to-Noise Ratio (SNR) Values for Solid Abdominal Organs.

PubMed

Herek, Duygu; Karabulut, Nevzat; Kocyıgıt, Ali; Yagcı, Ahmet Baki

2016-01-01

Our aim was to compare the apparent diffusion coefficient (ADC) values of normal abdominal parenchymal organs and signal-to-noise ratio (SNR) measurements in the same patients with breath hold (BH) and free breathing (FB) diffusion weighted imaging (DWI). Forty-eight patients underwent both BH and FB DWI. Spherical region of interest (ROI) was placed on the right hepatic lobe, spleen, pancreas, and renal cortices. ADC values were calculated for each organ on each sequence using an automated software. Image noise, defined as the standard deviation (SD) of the signal intensities in the most artifact-free area of the image background was measured by placing the largest possible ROI on either the left or the right side of the body outside the object in the recorded field of view. SNR was calculated using the formula: SNR=signal intensity (SI) (organ) /standard deviation (SD) (noise) . There were no statistically significant differences in ADC values of the abdominal organs between BH and FB DWI sequences ( p >0.05). There were statistically significant differences between SNR values of organs on BH and FB DWIs. SNRs were found to be better on FB DWI than BH DWI ( p <0.001). Free breathing DWI technique reduces image noise and increases SNR for abdominal examinations. Free breathing technique is therefore preferable to BH DWI in the evaluation of abdominal organs by DWI.

Feasibility of free-breathing dynamic contrast-enhanced MRI of gastric cancer using a golden-angle radial stack-of-stars VIBE sequence: comparison with the conventional contrast-enhanced breath-hold 3D VIBE sequence.

PubMed

Li, Huan-Huan; Zhu, Hui; Yue, Lei; Fu, Yi; Grimm, Robert; Stemmer, Alto; Fu, Cai-Xia; Peng, Wei-Jun

2018-05-01

To investigate the feasibility and diagnostic value of free-breathing, radial, stack-of-stars three-dimensional (3D) gradient echo (GRE) sequence ("golden angle") on dynamic contrast-enhanced (DCE) MRI of gastric cancer. Forty-three gastric cancer patients were divided into cooperative and uncooperative groups. Respiratory fluctuation was observed using an abdominal respiratory gating sensor. Those who breath-held for more than 15 s were placed in the cooperative group and the remainder in the uncooperative group. The 3-T MRI scanning protocol included 3D GRE and conventional breath-hold VIBE (volume-interpolated breath-hold examination) sequences, comparing images quantitatively and qualitatively. DCE-MRI parameters from VIBE images of normal gastric wall and malignant lesions were compared. For uncooperative patients, 3D GRE scored higher qualitatively, and had higher SNRs (signal-to-noise ratios) and CNRs (contrast-to-noise ratios) than conventional VIBE quantitatively. Though 3D GRE images scored lower in qualitative parameters compared with conventional VIBE for cooperative patients, it provided images with fewer artefacts. DCE parameters differed significantly between normal gastric wall and lesions, with higher Ve (extracellular volume) and lower Kep (reflux constant) in gastric cancer. The free-breathing, golden-angle, radial stack-of-stars 3D GRE technique is feasible for DCE-MRI of gastric cancer. Dynamic enhanced images can be used for quantitative analysis of this malignancy. • Golden-angle radial stack-of-stars VIBE aids gastric cancer MRI diagnosis. • The 3D GRE technique is suitable for patients unable to suspend respiration. • Method scored higher in the qualitative evaluation for uncooperative patients. • The technique produced images with fewer artefacts than conventional VIBE sequence. • Dynamic enhanced images can be used for quantitative analysis of gastric cancer.

β1-Blockade increases maximal apnea duration in elite breath-hold divers

PubMed Central

Ainslie, Philip N.; Bain, Anthony R.; MacLeod, David B.; Stembridge, Mike; Drvis, Ivan; Madden, Dennis; Barak, Otto; MacLeod, Douglas M.; Dujic, Zeljko

2017-01-01

We hypothesized that the cardioselective β1-adrenoreceptor antagonist esmolol would improve maximal apnea duration in elite breath-hold divers. In elite national-level divers (n = 9), maximal apneas were performed in a randomized and counterbalanced order while receiving either iv esmolol (150 μg·kg−1·min−1) or volume-matched saline (placebo). During apnea, heart rate (ECG), beat-by-beat blood pressure, stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were measured (finger photoplethysmography). Myocardial oxygen consumption (MV̇o2) was estimated from rate pressure product. Cerebral blood flow through the internal carotid (ICA) and vertebral arteries (VA) was assessed using Duplex ultrasound. Apnea duration improved in the esmolol trial when compared with placebo (356 ± 57 vs. 323 ± 61 s, P < 0.01) despite similar end-apnea peripheral oxyhemoglobin saturation (71.8 ± 10.3 vs. 74.9 ± 9.5%, P = 0.10). The HR response to apnea was reduced by esmolol at 10–30% of apnea duration, whereas MAP was unaffected. Esmolol reduced SV (main effect, P < 0.05) and CO (main effect; P < 0.05) and increased TPR (main effect, P < 0.05) throughout apnea. Esmolol also reduced MV̇o2 throughout apnea (main effect, P < 0.05). Cerebral blood flow through the ICA and VA was unchanged by esmolol at baseline and the last 30 s of apnea; however, global cerebral blood flow was reduced in the esmolol trial at end-apnea (P < 0.05). Our findings demonstrate that, in elite breath-hold divers, apnea breakpoint is improved by β1-blockade, likely owing to an improved total body oxygen sparring through increased centralization of blood volume (↑TPR) and reduced MV̇o2. NEW & NOTEWORTHY The governing bodies for international apnea competition, the Association Internationale pour le Développment de l’Apnée and La Confédération Mondaile des Activités Subaquatiques, have banned the use of β-blockers based on anecdotal reports that they improve apnea

Transpulmonary pressures and lung mechanics with glossopharyngeal insufflation and exsufflation beyond normal lung volumes in competitive breath-hold divers.

PubMed

Loring, Stephen H; O'Donnell, Carl R; Butler, James P; Lindholm, Peter; Jacobson, Francine; Ferrigno, Massimo

2007-03-01

Throughout life, most mammals breathe between maximal and minimal lung volumes determined by respiratory mechanics and muscle strength. In contrast, competitive breath-hold divers exceed these limits when they employ glossopharyngeal insufflation (GI) before a dive to increase lung gas volume (providing additional oxygen and intrapulmonary gas to prevent dangerous chest compression at depths recently greater than 100 m) and glossopharyngeal exsufflation (GE) during descent to draw air from compressed lungs into the pharynx for middle ear pressure equalization. To explore the mechanical effects of these maneuvers on the respiratory system, we measured lung volumes by helium dilution with spirometry and computed tomography and estimated transpulmonary pressures using an esophageal balloon after GI and GE in four competitive breath-hold divers. Maximal lung volume was increased after GI by 0.13-2.84 liters, resulting in volumes 1.5-7.9 SD above predicted values. The amount of gas in the lungs after GI increased by 0.59-4.16 liters, largely due to elevated intrapulmonary pressures of 52-109 cmH(2)O. The transpulmonary pressures increased after GI to values ranging from 43 to 80 cmH(2)O, 1.6-2.9 times the expected values at total lung capacity. After GE, lung volumes were reduced by 0.09-0.44 liters, and the corresponding transpulmonary pressures decreased to -15 to -31 cmH(2)O, suggesting closure of intrapulmonary airways. We conclude that the lungs of some healthy individuals are able to withstand repeated inflation to transpulmonary pressures far greater than those to which they would normally be exposed.

Comparison between deep breathing exercises and incentive spirometry after CABG surgery.

PubMed

Renault, Julia Alencar; Costa-Val, Ricardo; Rosseti, Márcia Braz; Houri Neto, Miguel

2009-01-01

To compare the effects of deep breathing exercises (DBE) and the flow-oriented incentive spirometry (IS) in patients undergone coronary artery bypass grafting (CABG) through the following variables: forced vital capacity - FVC, forced expiratory volume in 1 second - FEV(1), maximal respiratory pressures and oxygen saturation. Thirty six patients in CABG postoperative period underwent thirty minutes of non-invasive ventilation during the first 24 hours after extubation and were randomly shared into two groups as following: DBE (n=18) and IS (n=18). The spirometric variables were assessed on the preoperative period and seventh postoperative day (POD). The respiratory muscle strength and oxygen saturation were assessed on the preoperative period, first, second and seventh POD. The groups were considered homogeneous in relation to the demographic and surgical variables. It has been noted fall in the values of FVC and FEV(1) between the preoperative period and the seventh POD, but without significant differences between groups. The maximal respiratory pressures showed drop in the first POD but with and partial recovery until the seventh POD, also without significant differences between groups. The oxygen saturation was the only variable that was completely recovered on the seventh POD, also without significant differences between groups. There were not observed significant differences in maximal respiratory pressures, spirometric variables and oxygen saturation in patients undergone deep breathing exercises and flow-oriented incentive spirometry after coronary artery bypass grafting.

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

Controlled breathing protocols probe human autonomic cardiovascular rhythms

NASA Technical Reports Server (NTRS)

Cooke, W. H.; Cox, J. F.; Diedrich, A. M.; Taylor, J. A.; Beightol, L. A.; Ames, J. E. 4th; Hoag, J. B.; Seidel, H.; Eckberg, D. L.

1998-01-01

The purpose of this study was to determine how breathing protocols requiring varying degrees of control affect cardiovascular dynamics. We measured inspiratory volume, end-tidal CO2, R-R interval, and arterial pressure spectral power in 10 volunteers who followed the following 5 breathing protocols: 1) uncontrolled breathing for 5 min; 2) stepwise frequency breathing (at 0.3, 0.25, 0.2, 0.15, 0.1, and 0.05 Hz for 2 min each); 3) stepwise frequency breathing as above, but with prescribed tidal volumes; 4) random-frequency breathing (approximately 0.5-0.05 Hz) for 6 min; and 5) fixed-frequency breathing (0.25 Hz) for 5 min. During stepwise breathing, R-R interval and arterial pressure spectral power increased as breathing frequency decreased. Control of inspired volume reduced R-R interval spectral power during 0.1 Hz breathing (P < 0.05). Stepwise and random-breathing protocols yielded comparable coherence and transfer functions between respiration and R-R intervals and systolic pressure and R-R intervals. Random- and fixed-frequency breathing reduced end-tidal CO2 modestly (P < 0.05). Our data suggest that stringent tidal volume control attenuates low-frequency R-R interval oscillations and that fixed- and random-rate breathing may decrease CO2 chemoreceptor stimulation. We conclude that autonomic rhythms measured during different breathing protocols have much in common but that a stepwise protocol without stringent control of inspired volume may allow for the most efficient assessment of short-term respiratory-mediated autonomic oscillations.

Deep breathing exercises with positive expiratory pressure in patients with multiple sclerosis - a randomized controlled trial.

PubMed

Westerdahl, Elisabeth; Wittrin, Anna; Kånåhols, Margareta; Gunnarsson, Martin; Nilsagård, Ylva

2016-11-01

Breathing exercises with positive expiratory pressure are often recommended to patients with advanced neurological deficits, but the potential benefit in multiple sclerosis (MS) patients with mild and moderate symptoms has not yet been investigated in randomized controlled trials. To study the effects of 2 months of home-based breathing exercises for patients with mild to moderate MS on respiratory muscle strength, lung function, and subjective breathing and health status outcomes. Forty-eight patients with MS according to the revised McDonald criteria were enrolled in a randomized controlled trial. Patients performing breathing exercises (n = 23) were compared with a control group (n = 25) performing no breathing exercises. The breathing exercises were performed with a positive expiratory pressure device (10-15 cmH 2 O) and consisted of 30 slow deep breaths performed twice a day for 2 months. Respiratory muscle strength (maximal inspiratory and expiratory pressure at the mouth), spirometry, oxygenation, thoracic excursion, subjective perceptions of breathing and self-reported health status were evaluated before and after the intervention period. Following the intervention, there was a significant difference between the breathing group and the control group regarding the relative change in lung function, favoring the breathing group (vital capacity: P < 0.043; forced vital capacity: P < 0.025). There were no other significant differences between the groups. Breathing exercises may be beneficial in patients with mild to moderate stages of MS. However, the clinical significance needs to be clarified, and it remains to be seen whether a sustainable effect in delaying the development of respiratory dysfunction in MS can be obtained. © 2015 The Authors. The Clinical Respiratory Journal published by John Wiley & Sons Ltd.

How Does a Hopping Kangaroo Breathe?

ERIC Educational Resources Information Center

Giuliodori, Mauricio J.; Lujan, Heidi L.; Janbaih, Hussein; DiCarlo, Stephen E.

2010-01-01

We developed a model to demonstrate how a hopping kangaroo breathes. Interestingly, a kangaroo uses less energy to breathe while hopping than while standing still. This occurs, in part, because rather than using muscle power to move air into and out of the lungs, air is pulled into (inspiration) and pushed out of (expiration) the lungs as the…

Shortness of Breath

MedlinePlus

... with blood clots in the legs or pelvis (deep venous thrombosis), debilitating medical conditions, immobility, or inherited ... it hard for a person to take a deep breath, which usually results in retention of carbon ...

Respiratory-induced 3D deformations of the renal arteries quantified with geometric modeling during inspiration and expiration breath-holds of magnetic resonance angiography.

PubMed

Suh, Ga-Young; Choi, Gilwoo; Draney, Mary T; Herfkens, Robert J; Dalman, Ronald L; Cheng, Christopher P

2013-12-01

To quantify renal artery deformation due to respiration using magnetic resonance (MR) image-based geometric analysis. Five males were imaged with contrast-enhanced MR angiography during inspiratory and expiratory breath-holds. From 3D models of the abdominal aorta, left and right renal arteries (LRA and RRA), we quantified branching angle, curvature, peak curve angle, axial length, and locations of branch points. With expiration, maximum curvature changes were 0.054 ± 0.025 mm(-1) (P < 0.01), and curve angle at the most proximal curvature peak increased by 8.0 ± 4.5° (P < 0.05) in the LRA. Changes in maximum curvature and curve angles were not significant in the RRA. The first renal bifurcation point translated superiorly and posteriorly by 9.7 ± 3.6 mm (P < 0.005) and 3.5 ± 2.1 mm (P < 0.05), respectively, in the LRA, and 10.8 ± 6.1 mm (P < 0.05) and 3.6 ± 2.5 mm (P < 0.05), respectively, in the RRA. Changes in branching angle, axial length, and renal ostia locations were not significant. The LRA and RRA deformed and translated significantly. Greater deformation of the LRA as compared to the RRA may be due to asymmetric anatomy and mechanical support by the inferior vena cava. The presented methodology can extend to quantification of deformation of diseased and stented arteries to help renal artery implant development. Copyright © 2013 Wiley Periodicals, Inc.

Body Growth and Rapid Hematological Development Support Breath Hold of Baby Belugas (Delphinapterus leucas) during Subice Transit.

PubMed

Noren, Shawn R; Poll, Caryn P; Edwards, Matthew S

Body size and oxygen stores in the blood and muscle set breath-hold limits in marine mammals, yet these characteristics are understudied in immature cetaceans. We examined body mass and hematology from birth through adulthood in beluga whales (Delphinapterus leucas). At birth, body mass was 8% and 6% of the maximum mass recorded for adult females and males, respectively. Body mass then increased rapidly, approaching an asymptote around 12 yr for females and 18 yr for males. Interestingly, red blood cell counts, hemoglobin content, and hematocrit levels decreased after birth; this neonatal anemia was reversed as levels increased after 2 mo postpartum. Mature levels were obtained at approximately 8, 9, and 11 mo postpartum, respectively. Neonatal mean corpuscular hemoglobin also increased with ontogeny; mature levels were achieved by approximately 13 mo after birth. In contrast, mean corpuscular volume and mean corpuscular hemoglobin concentration demonstrated a significant but subtle increase throughout ontogeny. Our results indicate that postnatal maturation was required and that maturation occurred far earlier than the age at weaning (i.e., 2-3 yr postpartum). This is atypical of marine mammals, which generally achieve mature hemoglobin levels at weaning. Hematological maturation before maternal independence undoubtedly supports the prolonged breath holds of young belugas transiting under sea ice. This assessment enhances our knowledge of cetacean physiology and provides important inputs for determining age-specific dive capacity, yielding insights into age-specific flexibility to alter underwater behaviors, as will be required for future regime shifts and disturbances.

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

[Changes in P-wave, T-wave, and ST segment amplitude in 12 lead electrocardiogram in children with breath holding spell].

PubMed

Zhang, Wenhua; Wang, Cheng; Zou, Runmei; Liu, Liping; Wu, Lijia; Luo, Xuemei; Li, Fang; Liao, Donglei; Cai, Hong

2016-06-28

To explore the change of the amplitude of P wave, T wave and ST segment of 12 lead electrocardiogram (ECG) in children with breath holding spell.
 A total of 29 children (24 males and 5 females) with breath holding spell in Second Xiangya Hospital, Central South University were enrolled for this study from October, 2009 to September, 2015. Their ages ranged from 3 months to 6 years, with an average of 1.82±1.27 years old. The control group consisted of 30 age-matched and gender-matched healthy children. All subjects were underwent electrocardiography by the SR-1000A comprehensive automatic electrocardiograph analyzer, and the changes of the ECG parameters were compared between the two groups.
 Compared with the control group, the amplitude of P-wave of V5 lead was decreased [(44.10±23.98) vs (58.30±21.19) μV, P<0.05], the amplitude of T-wave of V6 lead was increased [(423.80±122.6) vs (350.00±105.73) μV, P<0.05], the amplitude of ST segment of II lead was increased [(84.80±39.97) vs (57.30±38.77) μV, P<0.05], the amplitude of ST segment of aVR lead was increased [(-77.60±37.41) vs (-51.00±33.46) μV, P<0.05], the amplitude of ST segment of aVL lead was increased [(35.20±28.24) vs (17.70±33.90) μV, P<0.05], the amplitude of ST segment of V5 lead was increased [(111.00±59.36) vs (69.00±36.33) μV, P<0.05], the amplitude of ST segment of V6 lead was increased [(79.30±45.51) vs (51.30±33.19) μV, P<0.05]. 
 The children with breath holding spell have autonomic nerve dysfunction. The amplitude of ST segment changes is sensitive.

INSPIRE and MarCO - Technology Development for the First Deep Space CubeSats

NASA Astrophysics Data System (ADS)

Klesh, Andrew

2016-07-01

INSPIRE (Interplanetary NanoSpacecraft Pathfinder In a Relevant Environment) and MarCO (Mars Cube One) will open the door for tiny spacecraft to explore the solar system. INSPIRE serves as a trailblazer, designed to demonstrate new technology needed for deep space. MarCO will open the door for NanoSpacecraft to serve in support roles for much larger primary missions - in this case, providing a real-time relay of for the InSight project and will likely be the first CubeSats to reach deep space. Together, these four spacecraft (two for each mission) enable fundamental science objectives to be met with tiny vehicles. Originally designed for a March, 2016 launch with the InSight mission to Mars, the MarCO spacecraft are now complete and in storage. When launched with the InSight lander from Vandenberg Air Force Base, the spacecraft will begin a 6.5 month cruise to Mars. Soon after InSight itself separates from the upper stage of the launch vehicle, the two MarCO CubeSats will deploy and independently fly to Mars to support telecommunications relay for InSight's entry, descent, and landing sequence. These spacecraft will have onboard capability for deep space trajectory correction maneuvers; high-speed direct-to-Earth & DSN-compatible communications; an advanced navigation transponder; a large deployable reflect-array high gain antenna; and a robust software suite. This talk will present an overview of the INSPIRE and MarCO projects, including a concept of operations, details of the spacecraft and subsystem design, and lessons learned from integration and test. Finally, the talk will outline how lessons from these spacecraft are already being utilized in the next generation of interplanetary CubeSats, as well as a brief vision of their applicability for solar system exploration. The research described here was carried out at the Jet Propulsion Laboratory, Caltech, under a contract with the National Aeronautics and Space Administration (NASA).

Ventilation heterogeneity measured by multiple breath inert gas testing is not affected by inspired oxygen concentration in healthy humans

PubMed Central

Elliott, Ann R.; Prisk, G. Kim; Darquenne, Chantal

2017-01-01

Multiple breath washout (MBW) and oxygen-enhanced MRI techniques use acute exposure to 100% oxygen to measure ventilation heterogeneity. Implicit is the assumption that breathing 100% oxygen does not induce changes in ventilation heterogeneity; however, this is untested. We hypothesized that ventilation heterogeneity decreases with increasing inspired oxygen concentration in healthy subjects. We performed MBW in 8 healthy subjects (4 women, 4 men; age = 43 ± 15 yr) with normal pulmonary function (FEV1 = 98 ± 6% predicted) using 10% argon as a tracer gas and oxygen concentrations of 12.5%, 21%, or 90%. MBW was performed in accordance with ERS-ATS guidelines. Subjects initially inspired air followed by a wash-in of test gas. Tests were performed in balanced order in triplicate. Gas concentrations were measured at the mouth, and argon signals rescaled to mimic a N2 washout, and analyzed to determine the distribution of specific ventilation (SV). Heterogeneity was characterized by the width of a log-Gaussian fit of the SV distribution and from Sacin and Scond indexes derived from the phase III slope. There were no significant differences in the ventilation heterogeneity due to altered inspired oxygen: histogram width (hypoxia 0.57 ± 0.11, normoxia 0.60 ± 0.08, hyperoxia 0.59 ± 0.09, P = 0.51), Scond (hypoxia 0.014 ± 0.011, normoxia 0.012 ± 0.015, hyperoxia 0.010 ± 0.011, P = 0.34), or Sacin (hypoxia 0.11 ± 0.04, normoxia 0.10 ± 0.03, hyperoxia 0.12 ± 0.03, P = 0.23). Functional residual capacity was increased in hypoxia (P = 0.04) and dead space increased in hyperoxia (P = 0.0001) compared with the other conditions. The acute use of 100% oxygen in MBW or MRI is unlikely to affect ventilation heterogeneity. NEW & NOTEWORTHY Hyperoxia is used to measure the distribution of ventilation in imaging and MBW but may alter the underlying ventilation distribution. We used MBW to evaluate the effect of inspired oxygen concentration on the ventilation distribution

Ventilation heterogeneity measured by multiple breath inert gas testing is not affected by inspired oxygen concentration in healthy humans.

PubMed

Hopkins, Susan R; Elliott, Ann R; Prisk, G Kim; Darquenne, Chantal

2017-06-01

Multiple breath washout (MBW) and oxygen-enhanced MRI techniques use acute exposure to 100% oxygen to measure ventilation heterogeneity. Implicit is the assumption that breathing 100% oxygen does not induce changes in ventilation heterogeneity; however, this is untested. We hypothesized that ventilation heterogeneity decreases with increasing inspired oxygen concentration in healthy subjects. We performed MBW in 8 healthy subjects (4 women, 4 men; age = 43 ± 15 yr) with normal pulmonary function (FEV 1 = 98 ± 6% predicted) using 10% argon as a tracer gas and oxygen concentrations of 12.5%, 21%, or 90%. MBW was performed in accordance with ERS-ATS guidelines. Subjects initially inspired air followed by a wash-in of test gas. Tests were performed in balanced order in triplicate. Gas concentrations were measured at the mouth, and argon signals rescaled to mimic a N 2 washout, and analyzed to determine the distribution of specific ventilation (SV). Heterogeneity was characterized by the width of a log-Gaussian fit of the SV distribution and from S acin and S cond indexes derived from the phase III slope. There were no significant differences in the ventilation heterogeneity due to altered inspired oxygen: histogram width (hypoxia 0.57 ± 0.11, normoxia 0.60 ± 0.08, hyperoxia 0.59 ± 0.09, P = 0.51), S cond (hypoxia 0.014 ± 0.011, normoxia 0.012 ± 0.015, hyperoxia 0.010 ± 0.011, P = 0.34), or S acin (hypoxia 0.11 ± 0.04, normoxia 0.10 ± 0.03, hyperoxia 0.12 ± 0.03, P = 0.23). Functional residual capacity was increased in hypoxia ( P = 0.04) and dead space increased in hyperoxia ( P = 0.0001) compared with the other conditions. The acute use of 100% oxygen in MBW or MRI is unlikely to affect ventilation heterogeneity. NEW & NOTEWORTHY Hyperoxia is used to measure the distribution of ventilation in imaging and MBW but may alter the underlying ventilation distribution. We used MBW to evaluate the effect of inspired oxygen concentration on the ventilation

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.

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

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

Pulmonary ventilation-perfusion mismatch: a novel hypothesis for how diving vertebrates may avoid the bends.

PubMed

Garcia Párraga, Daniel; Moore, Michael; Fahlman, Andreas

2018-04-25

Hydrostatic lung compression in diving marine mammals, with collapsing alveoli blocking gas exchange at depth, has been the main theoretical basis for limiting N 2 uptake and avoiding gas emboli (GE) as they ascend. However, studies of beached and bycaught cetaceans and sea turtles imply that air-breathing marine vertebrates may, under unusual circumstances, develop GE that result in decompression sickness (DCS) symptoms. Theoretical modelling of tissue and blood gas dynamics of breath-hold divers suggests that changes in perfusion and blood flow distribution may also play a significant role. The results from the modelling work suggest that our current understanding of diving physiology in many species is poor, as the models predict blood and tissue N 2 levels that would result in severe DCS symptoms (chokes, paralysis and death) in a large fraction of natural dive profiles. In this review, we combine published results from marine mammals and turtles to propose alternative mechanisms for how marine vertebrates control gas exchange in the lung, through management of the pulmonary distribution of alveolar ventilation ([Formula: see text]) and cardiac output/lung perfusion ([Formula: see text]), varying the level of [Formula: see text] in different regions of the lung. Man-made disturbances, causing stress, could alter the [Formula: see text] mismatch level in the lung, resulting in an abnormally elevated uptake of N 2 , increasing the risk for GE. Our hypothesis provides avenues for new areas of research, offers an explanation for how sonar exposure may alter physiology causing GE and provides a new mechanism for how air-breathing marine vertebrates usually avoid the diving-related problems observed in human divers. © 2018 The Authors.

Measuring vascular reactivity with breath-holds after stroke: a method to aid interpretation of group-level BOLD signal changes in longitudinal fMRI studies.

PubMed

Geranmayeh, Fatemeh; Wise, Richard J S; Leech, Robert; Murphy, Kevin

2015-05-01

Blood oxygenation level-dependent (BOLD) contrast functional magnetic resonance imaging (fMRI) is a widely used technique to map brain function, and to monitor its recovery after stroke. Since stroke has a vascular etiology, the neurovascular coupling between cerebral blood flow and neural activity may be altered, resulting in uncertainties when interpreting longitudinal BOLD signal changes. The purpose of this study was to demonstrate the feasibility of using a recently validated breath-hold task in patients with stroke, both to assess group level changes in cerebrovascular reactivity (CVR) and to determine if alterations in regional CVR over time will adversely affect interpretation of task-related BOLD signal changes. Three methods of analyzing the breath-hold data were evaluated. The CVR measures were compared over healthy tissue, infarcted tissue and the peri-infarct tissue, both sub-acutely (∼2 weeks) and chronically (∼4 months). In this cohort, a lack of CVR differences in healthy tissue between the patients and controls indicates that any group level BOLD signal change observed in these regions over time is unlikely to be related to vascular alterations. CVR was reduced in the peri-infarct tissue but remained unchanged over time. Therefore, although a lack of activation in this region compared with the controls may be confounded by a reduced CVR, longitudinal group-level BOLD changes may be more confidently attributed to neural activity changes in this cohort. By including this breath-hold-based CVR assessment protocol in future studies of stroke recovery, researchers can be more assured that longitudinal changes in BOLD signal reflect true alterations in neural activity. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Mechanical indentation improves cerebral blood oxygenation signal quality of functional near-infrared spectroscopy (fNIRS) during breath holding

NASA Astrophysics Data System (ADS)

Vogt, William C.; Romero, Edwin; LaConte, Stephen M.; Rylander, Christopher G.

2013-03-01

Functional near-infrared spectroscopy (fNIRS) is a well-known technique for non-invasively measuring cerebral blood oxygenation, and many studies have demonstrated that fNIRS signals can be related to cognitive function. However, the fNIRS signal is attenuated by the skin, while scalp blood content has been reported to influence cerebral oxygenation measurements. Mechanical indentation has been shown to increase light transmission through soft tissues by causing interstitial water and blood flow away from the compressed region. To study the effects of indentation on fNIRS, a commercial fNIRS system with 16 emitter/detector pairs was used to measure cerebral blood oxygenation at 2 Hz. This device used diffuse reflectance at 730 nm and 850 nm to calculate deoxy- and oxy-hemoglobin concentrations. A borosilicate glass hemisphere was epoxied over each sensor to function as both an indenter and a lens. After placing the indenter/sensor assembly on the forehead, a pair of plastic bands was placed on top of the fNIRS headband and strapped to the head to provide uniform pressure and tightened to approx. 15 N per strap. Cerebral blood oxygenation was recorded during a breath holding regime (15 second hold, 15 second rest, 6 cycles) in 4 human subjects both with and without the indenter array. Results showed that indentation increased raw signal intensity by 85 +/- 35%, and that indentation increased amplitude of hemoglobin changes during breath cycles by 313% +/- 105%. These results suggest that indentation improves sensing of cerebral blood oxygenation, and may potentially enable sensing of deeper brain tissues.

Photogrammetry of fetal breathing movements during the third trimester of pregnancy: observations in normal and abnormal pregnancies.

PubMed

Florido, J; Padilla, M C; Soto, V; Camacho, A; Moscoso, G; Navarrete, L

2008-09-01

To evaluate parameters of fetal breathing movements-displacement of the fetal abdominal wall during inspiration and expiration, time of inspiration and expiration and speed of inspiration and expiration-between 30 and 36 weeks' gestation in normal pregnancies, and in those complicated by gestational diabetes or maternal hypertension. Three categories of pregnancy were investigated: 49 were normal, 16 had pregnancy-induced diabetes and 10 were hypertensive. According to their gestational age, the patients were divided into two groups: Group A between 30 and 32 weeks' gestation and Group B between 33 and 36 weeks. Using photogrammetry and a computer-operated algorithm, six parameters of fetal breathing movements were investigated. There were significant differences in the various fetal parameters measured among the three categories of pregnant women. Up until 32 weeks of gestation, the displacements during inspiration and expiration were larger, the speeds of inspiration and expiration were higher, and the times for inspiration and expiration were shorter in the diabetic and hypertensive groups than in the normal group. In the later period, between 33 and 36 weeks, fetuses of pregnancy-induced diabetic patients showed the lowest inspiration and expiration times and the highest speeds of inspiration and expiration. Photogrammetry in conjunction with a computer-operated algorithm can be used to assess fetal breathing movements. There are significant differences in fetal breathing movements between normal pregnancies and those that are complicated by gestational diabetes or hypertension.

[Pursed Lips Inspiration for Vocal Cord Dysfunction].

PubMed

Maruyama, Yumiko; Tsukada, Yayoi; Hirai, Nobuyuki; Nakanishi, Yosuke; Yoshizaki, Tomokazu

2015-01-01

Paradoxical vocal cord motion (PVCM) during vocal cord dysfunction (VCD) generally occurs spasmodically and transiently. After we had experienced 36 cases of VCD and successfully treated with conservative treatment including "pursed lips inspiration" method, we experienced a boy who had persistent PVCM. It was observed his PVCM vanished when he breathed in through pursed lips, while it appeared again when he stopped pursed lips inspiration. An airway reflex has been reported where the negative pressure in the subglottic space resulting from the inspiratory effort against a narrowed glottis activates the vocal cord adductor. VCD is considered to have both acceleration of laryngeal closure reflex against airway stimuli and active adductive movement of vocal cords against negative pressure in the subglottic space as underlying factors. The pursed lips inspiration method enables VCD patients not only to accomplish slow and light breathing but also to decrease the difference in the pressure between the supra--and subglottic space by occluding the nasal cavity and voluntary puckering up of the mouth which generate negative pressure in the supraglottic space. This is the first report of the pursed lips inspiration method as a treatment for VCD. Pursed lips inspiration is a simple method which is easy to perform anytime, anywhere without any special equipment, and is considered to be worth trying for VCD.

Quantification of Contralateral Breast Dose and Risk Estimate of Radiation-Induced Contralateral Breast Cancer Among Young Women Using Tangential Fields and Different Modes of Breathing

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

Zurl, Brigitte, E-mail: brigitte.zurl@klinikum-graz.at; Stranzl, Heidi; Winkler, Peter

2013-02-01

Purpose: Whole breast irradiation with deep-inspiration breath-hold (DIBH) technique among left-sided breast cancer patients significantly reduces cardiac irradiation; however, a potential disadvantage is increased incidental irradiation of the contralateral breast. Methods and Materials: Contralateral breast dose (CBD) was calculated by comparing 400 treatment plans of 200 left-sided breast cancer patients whose tangential fields had been planned on gated and nongated CT data sets. Various anatomic and field parameters were analyzed for their impact on CBD. For a subgroup of patients (aged {<=}45 years) second cancer risk in the contralateral breast (CB) was modeled by applying the linear quadratic model, compoundmore » models, and compound models considering dose-volume information (DVH). Results: The mean CBD was significantly higher in DIBH with 0.69 Gy compared with 0.65 Gy in normal breathing (P=.01). The greatest impact on CBD was due to a shift of the inner field margin toward the CB in DIBH (mean 0.4 cm; range, 0-2), followed by field size in magnitude. Calculation with different risk models for CBC revealed values of excess relative risk/Gy ranging from 0.48-0.65 vs 0.46-0.61 for DIBH vs normal breathing, respectively. Conclusion: Contralateral breast dose, although within a low dose range, was mildly but significantly increased in 200 treatment plans generated under gated conditions, predominately due to a shift in the medial field margin. Risk modeling for CBC among women aged {<=}45 years also pointed to a higher risk when comparing DIBH with normal breathing. This risk, however, was substantially lower in the model considering DVH information. We think that clinical decisions should not be affected by this small increase in CBD with DIBH because DIBH is effective in reducing the dose to the heart in all patients.« less

The effect of deep and slow breathing on pain perception, autonomic activity, and mood processing--an experimental study.

PubMed

Busch, Volker; Magerl, Walter; Kern, Uwe; Haas, Joachim; Hajak, Göran; Eichhammer, Peter

2012-02-01

Deep and slow breathing (DSB) techniques, as a component of various relaxation techniques, have been reported as complementary approaches in the treatment of chronic pain syndromes, but the relevance of relaxation for alleviating pain during a breathing intervention was not evaluated so far. In order to disentangle the effects of relaxation and respiration, we investigated two different DSB techniques at the same respiration rates and depths on pain perception, autonomic activity, and mood in 16 healthy subjects. In the attentive DSB intervention, subjects were asked to breathe guided by a respiratory feedback task requiring a high degree of concentration and constant attention. In the relaxing DSB intervention, the subjects relaxed during the breathing training. The skin conductance levels, indicating sympathetic tone, were measured during the breathing maneuvers. Thermal detection and pain thresholds for cold and hot stimuli and profile of mood states were examined before and after the breathing sessions. The mean detection and pain thresholds showed a significant increase resulting from the relaxing DSB, whereas no significant changes of these thresholds were found associated with the attentive DSB. The mean skin conductance levels indicating sympathetic activity decreased significantly during the relaxing DSB intervention but not during the attentive DSB. Both breathing interventions showed similar reductions in negative feelings (tension, anger, and depression). Our results suggest that the way of breathing decisively influences autonomic and pain processing, thereby identifying DSB in concert with relaxation as the essential feature in the modulation of sympathetic arousal and pain perception. Wiley Periodicals, Inc.

Detection of pulmonary metastases with pathological correlation: effect of breathing on the accuracy of spiral CT.

PubMed

Coakley, F V; Cohen, M D; Waters, D J; Davis, M M; Karmazyn, B; Gonin, R; Hanna, M P

1997-07-01

CT of the chest for suspected pulmonary metastases in adults is generally performed using a breath-hold technique. The results may not be applicable to young children in whom breath-holding may be impossible. Determine the effect of breathing on the accuracy of pulmonary metastasis detection by spiral CT (SCT). Prior to euthanasia four anesthetized dogs with metastatic osteosarcoma underwent SCT with a collimation of 5 mm and a pitch of 2, during both induced breath-hold and normal quiet breathing. Images were reconstructed as contiguous 5-mm slices. Macroscopically evident metastases were noted at postmortem. Hard-copy SCT images were reviewed by ten radiologists, each of whom circled all suspected metastases. SCT images were compared with postmortem results to determine true and false positives. The pathologist identified 132 macroscopically evident pulmonary metastases. For metastasis detection, there was no significant difference between breath-hold SCT and breathing SCT. In our animal model, SCT can be performed during normal resting breathing without significant loss of accuracy in the detection of pulmonary metastases.

[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.

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.

High-pitch Helical Dual-source Computed Tomographic Pulmonary Angiography: Comparing Image Quality in Inspiratory Breath-hold and During Free Breathing.

PubMed

Ajlan, Amr M; Binzaqr, Salma; Jadkarim, Dalia A; Jamjoom, Lamia G; Leipsic, Jonathon

2016-01-01

The purpose of this study was to compare qualitative and quantitative image parameters of dual-source high-pitch helical computed tomographic pulmonary angiography (CTPA) in breath-holding (BH) versus free-breathing (FB) patients. Ninety-nine consented patients (61 female individuals; mean age±SD, 49±18.7 y) were randomized into BH (n=45) versus FB (n=54) high-pitch helical CTPA. Patient characteristics and CTPA radiation doses were analyzed. Two readers assessed for pulmonary embolism (PE), transient interruption of contrast, and respiratory and cardiac motion. The readers used a subjective 3-point scale to rate the pulmonary artery opacification and lung parenchymal appearance. A single reader assessed mean pulmonary artery signal intensity, noise, contrast, signal to noise ratio, and contrast to noise ratio. PE was diagnosed in 16% BH and 19% FB patients. CTPAs of both groups were of excellent or acceptable quality for PE evaluation and of similar mean radiation doses (1.3 mSv). Transient interruption of contrast was seen in 5/45 (11%) BH and 5/54 (9%) FB patients (not statistically significant, P=0.54). No statistically significant difference was noted in cardiac, diaphragmatic, and lung parenchymal motion. Lung parenchymal assessment was excellent in all cases, except for 5/54 (9%) motion-affected FB cases with acceptable quality (statistically significant, P=0.03). No CTPA was considered nondiagnostic by any of the readers. No objective image quality differences were noted between both groups (P>0.05). High-pitch helical CTPA acquired during BH or in FB yields comparable image quality for the diagnosis of PE and lung pathology, with low radiation exposure. Only a modest increase in lung parenchymal artifacts is encountered in FB high-pitch helical CTPA.

Cardiorespiratory adaptation to breath-holding in air: Analysis via a cardiopulmonary simulation model.

PubMed

Albanese, Antonio; Limei Cheng; Ursino, Mauro; Chbat, Nicolas W

2015-01-01

Apnea via breath-holding (BH) in air induces cardiorespiratory adaptation that involves the activation of several reflex mechanisms and their complex interactions. Hence, the effects of BH in air on cardiorespiratory function can become hardly predictable and difficult to be interpreted. Particularly, the effect on heart rate is not yet completely understood because of the contradicting results of different physiological studies. In this paper we apply our previously developed cardiopulmonary model (CP Model) to a scenario of BH with a twofold intent: (1) further validating the CP Model via comparison against experimental data; (2) gaining insights into the physiological reasoning for such contradicting experimental results. Model predictions agreed with published experimental animal and human data and indicated that heart rate increases during BH in air. Changes in the balance between sympathetic and vagal effects on heart rate within the model proved to be effective in inverting directions of the heart rate changes during BH. Hence, the model suggests that intra-subject differences in such sympatho-vagal balance may be one of the reasons for the contradicting experimental results.

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.

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

First MRI application of an active breathing coordinator

NASA Astrophysics Data System (ADS)

Kaza, E.; Symonds-Tayler, R.; Collins, D. J.; McDonald, F.; McNair, H. A.; Scurr, E.; Koh, D.-M.; Leach, M. O.

2015-02-01

A commercial active breathing coordinator (ABC) device, employed to hold respiration at a specific level for a predefined duration, was successfully adapted for magnetic resonance imaging (MRI) use for the first time. Potential effects of the necessary modifications were assessed and taken into account. Automatic MR acquisition during ABC breath holding was achieved. The feasibility of MR-ABC thoracic and abdominal examinations together with the advantages of imaging in repeated ABC-controlled breath holds were demonstrated on healthy volunteers. Five lung cancer patients were imaged under MR-ABC, visually confirming the very good intra-session reproducibility of organ position in images acquired with the same patient positioning as used for computed tomography (CT). Using identical ABC settings, good MR-CT inter-modality registration was achieved. This demonstrates the value of ABC, since application of T1, T2 and diffusion weighted MR sequences provides a wider range of contrast mechanisms and additional diagnostic information compared to CT, thus improving radiotherapy treatment planning and assessment.

First MRI application of an active breathing coordinator.

PubMed

Kaza, E; Symonds-Tayler, R; Collins, D J; McDonald, F; McNair, H A; Scurr, E; Koh, D-M; Leach, M O

2015-02-21

A commercial active breathing coordinator (ABC) device, employed to hold respiration at a specific level for a predefined duration, was successfully adapted for magnetic resonance imaging (MRI) use for the first time. Potential effects of the necessary modifications were assessed and taken into account. Automatic MR acquisition during ABC breath holding was achieved. The feasibility of MR-ABC thoracic and abdominal examinations together with the advantages of imaging in repeated ABC-controlled breath holds were demonstrated on healthy volunteers. Five lung cancer patients were imaged under MR-ABC, visually confirming the very good intra-session reproducibility of organ position in images acquired with the same patient positioning as used for computed tomography (CT). Using identical ABC settings, good MR-CT inter-modality registration was achieved. This demonstrates the value of ABC, since application of T1, T2 and diffusion weighted MR sequences provides a wider range of contrast mechanisms and additional diagnostic information compared to CT, thus improving radiotherapy treatment planning and assessment.

First MRI application of an active breathing coordinator

PubMed Central

Kaza, E; Symonds-Tayler, R; Collins, D J; McDonald, F; McNair, H A; Scurr, E; Koh, D-M; Leach, M O

2015-01-01

Abstract A commercial active breathing coordinator (ABC) device, employed to hold respiration at a specific level for a predefined duration, was successfully adapted for magnetic resonance imaging (MRI) use for the first time. Potential effects of the necessary modifications were assessed and taken into account. Automatic MR acquisition during ABC breath holding was achieved. The feasibility of MR-ABC thoracic and abdominal examinations together with the advantages of imaging in repeated ABC-controlled breath holds were demonstrated on healthy volunteers. Five lung cancer patients were imaged under MR-ABC, visually confirming the very good intra-session reproducibility of organ position in images acquired with the same patient positioning as used for computed tomography (CT). Using identical ABC settings, good MR-CT inter-modality registration was achieved. This demonstrates the value of ABC, since application of T1, T2 and diffusion weighted MR sequences provides a wider range of contrast mechanisms and additional diagnostic information compared to CT, thus improving radiotherapy treatment planning and assessment. PMID:25633183

Effect of stratified inequality of blood flow on gas exchange in liquid-filled lungs.

NASA Technical Reports Server (NTRS)

West, J. B.; Maloney, J. E.; Castle, B. L.

1972-01-01

This investigation set out to answer two questions: (1) are the distal alveoli in the terminal lung units less well perfused than the proximal alveoli, i.e., is there stratification of blood flow; and (2) if so, does this enhance gas exchange in the presence of stratified inequality of ventilation. Excised dog lungs were ventilated with saline and perfused with blood. Following single inspirations of xenon 133 in saline and various periods of breath holding, the expired xenon concentration against volume was measured and it confirmed marked stratified inequality of ventilation under these conditions. By measuring the rate of depletion of xenon from alveoli during a period of blood flow, we showed that the alveoli which emptied at the end of expiration had 16% less blood flow than those exhaling earlier. However, by measuring the xenon concentration in pulmonary venous blood, we found that about 10% less tracer was transferred from the alveoli into the blood when the inspired xenon was stratified within the respiratory zone. Thus while stratification of blood flow was confirmed, it was shown to impair rather than enhance the efficiency of gas transfer.

SU-G-BRC-13: Model Based Classification for Optimal Position Selection for Left-Sided Breast Radiotherapy: Free Breathing, DIBH, Or Prone

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

Lin, H; Liu, T; Xu, X

Purpose: There are clinical decision challenges to select optimal treatment positions for left-sided breast cancer patients—supine free breathing (FB), supine Deep Inspiration Breath Hold (DIBH) and prone free breathing (prone). Physicians often make the decision based on experiences and trials, which might not always result optimal OAR doses. We herein propose a mathematical model to predict the lowest OAR doses among these three positions, providing a quantitative tool for corresponding clinical decision. Methods: Patients were scanned in FB, DIBH, and prone positions under an IRB approved protocol. Tangential beam plans were generated for each position, and OAR doses were calculated.more » The position with least OAR doses is defined as the optimal position. The following features were extracted from each scan to build the model: heart, ipsilateral lung, breast volume, in-field heart, ipsilateral lung volume, distance between heart and target, laterality of heart, and dose to heart and ipsilateral lung. Principal Components Analysis (PCA) was applied to remove the co-linearity of the input data and also to lower the data dimensionality. Feature selection, another method to reduce dimensionality, was applied as a comparison. Support Vector Machine (SVM) was then used for classification. Thirtyseven patient data were acquired; up to now, five patient plans were available. K-fold cross validation was used to validate the accuracy of the classifier model with small training size. Results: The classification results and K-fold cross validation demonstrated the model is capable of predicting the optimal position for patients. The accuracy of K-fold cross validations has reached 80%. Compared to PCA, feature selection allows causal features of dose to be determined. This provides more clinical insights. Conclusion: The proposed classification system appeared to be feasible. We are generating plans for the rest of the 37 patient images, and more statistically

Simple retrograde cerebral perfusion is as good as complex antegrade cerebral perfusion for hemiarch replacement.

PubMed

Tanaka, Akiko; Estrera, Anthony L

2018-01-01

Cerebral complication is a major concern after aortic arch surgery, which may lead to death. Thus, cerebral protection strategy plays the key role to obtain respectable results in aortic arch repair. Deep hypothermic circulatory arrest was introduced in 1970s to decrease the ischemic insults to the brain. However, safe duration of circulatory arrest time was limited to 30 minutes. The 1990s was the decade of evolution for cerebral protection, in which two adjuncts for deep hypothermic circulatory arrest were introduced: retrograde and antegrade cerebral perfusion (ACP) techniques. These two cerebral perfusion techniques significantly decreased incidence of postoperative neurological dysfunction and mortality after aortic arch surgery. Although there are no large prospective studies that demonstrate which perfusion technique provide better outcomes, multiple retrospective studies implicate that ACP may decrease cerebral complications compared to retrograde cerebral perfusion (RCP) when a long circulatory arrest time is required during aortic arch reconstructions. To date, many surgeons favor ACP over RCP during a complex aortic arch repair, such as total arch replacement and hybrid arch replacement. However, the question is whether the use of ACP is necessary during a short, limited circulatory arrest time, such as hemiarch replacement? There is a paucity of data that proves the advantages of a complex ACP over a simple RCP for a short circulatory arrest time. RCP with deep hypothermic circulatory arrest is the simple, efficient cerebral protection technique with minimal interference to the surgical field-and it potentially allows to flush atheromatous debris out from the arch vessels. Thus, it is the preferred adjunct to deep hypothermic circulatory arrest during hemiarch replacement in our institution.

Simple retrograde cerebral perfusion is as good as complex antegrade cerebral perfusion for hemiarch replacement

PubMed Central

Tanaka, Akiko

2018-01-01

Cerebral complication is a major concern after aortic arch surgery, which may lead to death. Thus, cerebral protection strategy plays the key role to obtain respectable results in aortic arch repair. Deep hypothermic circulatory arrest was introduced in 1970s to decrease the ischemic insults to the brain. However, safe duration of circulatory arrest time was limited to 30 minutes. The 1990s was the decade of evolution for cerebral protection, in which two adjuncts for deep hypothermic circulatory arrest were introduced: retrograde and antegrade cerebral perfusion (ACP) techniques. These two cerebral perfusion techniques significantly decreased incidence of postoperative neurological dysfunction and mortality after aortic arch surgery. Although there are no large prospective studies that demonstrate which perfusion technique provide better outcomes, multiple retrospective studies implicate that ACP may decrease cerebral complications compared to retrograde cerebral perfusion (RCP) when a long circulatory arrest time is required during aortic arch reconstructions. To date, many surgeons favor ACP over RCP during a complex aortic arch repair, such as total arch replacement and hybrid arch replacement. However, the question is whether the use of ACP is necessary during a short, limited circulatory arrest time, such as hemiarch replacement? There is a paucity of data that proves the advantages of a complex ACP over a simple RCP for a short circulatory arrest time. RCP with deep hypothermic circulatory arrest is the simple, efficient cerebral protection technique with minimal interference to the surgical field—and it potentially allows to flush atheromatous debris out from the arch vessels. Thus, it is the preferred adjunct to deep hypothermic circulatory arrest during hemiarch replacement in our institution. PMID:29682460

The effects of furosemide on remal blood flow and cortical perfusion during methoxyflurane and halothane anaesthesia.

PubMed

Leighton, K M; Bruce, C; Machin, R

1976-01-01

Nephrotoxicity due to methoxyflurane may be due in part to alterations in intra-renal perfusion. Furosemide is believed to alter the intra-renal distribution of blood flow. Studies have been carried out to observe the effects of systemic furosemide administration during methoxyflurane and halothane anaesthesia in normotensive animals and in animals made hypotensive by increasing inspired concentrations of the anaesthetics. During halothane anaesthesia normotensive dogs showed a rise in total renal blood flow during the infusion of furosemide. Hypotensive dogs showed no increase in flow. During methoxyflurane anaesthesia no change in total renal blood flow followed furosemide administration to normotensive animals. Some diminution in total blood flow followed the administration of furosemide in hypotensive dogs during methoxyflurane anaesthesia. In normotensive dogs during halothane anaesthesia there was a significant increase in deep cortical perfusion after furosemide. Furosemide, therefore, is unlikely to mitigate the potential for nephrotoxicity which methoxyflurane possesses. Furthermore, this diuretic may adversely influence renal function when administered during halothane anaesthesia.

Phase Synchronization of Hemodynamic Variables at Rest and after Deep Breathing Measured during the Course of Pregnancy

PubMed Central

Papousek, Ilona; Roessler, Andreas; Hinghofer-Szalkay, Helmut; Lang, Uwe; Kolovetsiou-Kreiner, Vassiliki

2013-01-01

Background The autonomic nervous system plays a central role in the functioning of systems critical for the homeostasis maintenance. However, its role in the cardiovascular adaptation to pregnancy-related demands is poorly understood. We explored the maternal cardiovascular systems throughout pregnancy to quantify pregnancy-related autonomic nervous system adaptations. Methodology Continuous monitoring of heart rate (R-R interval; derived from the 3-lead electrocardiography), blood pressure, and thoracic impedance was carried out in thirty-six women at six time-points throughout pregnancy. In order to quantify in addition to the longitudinal effects on baseline levels throughout gestation the immediate adaptive heart rate and blood pressure changes at each time point, a simple reflex test, deep breathing, was applied. Consequently, heart rate variability and blood pressure variability in the low (LF) and high (HF) frequency range, respiration and baroreceptor sensitivity were analyzed in resting conditions and after deep breathing. The adjustment of the rhythms of the R-R interval, blood pressure and respiration partitioned for the sympathetic and the parasympathetic branch of the autonomic nervous system were quantified by the phase synchronization index γ, which has been adopted from the analysis of weakly coupled chaotic oscillators. Results Heart rate and LF/HF ratio increased throughout pregnancy and these effects were accompanied by a continuous loss of baroreceptor sensitivity. The increases in heart rate and LF/HF ratio levels were associated with an increasing decline in the ability to flexibly respond to additional demands (i.e., diminished adaptive responses to deep breathing). The phase synchronization index γ showed that the observed effects could be explained by a decreased coupling of respiration and the cardiovascular system (HF components of heart rate and blood pressure). Conclusions/Significance The findings suggest that during the course of

The Cellular Building Blocks of Breathing

PubMed Central

Ramirez, J.M.; Doi, A.; Garcia, A.J.; Elsen, F.P.; Koch, H.; Wei, A.D.

2013-01-01

Respiratory brainstem neurons fulfill critical roles in controlling breathing: they generate the activity patterns for breathing and contribute to various sensory responses including changes in O2 and CO2. These complex sensorimotor tasks depend on the dynamic interplay between numerous cellular building blocks that consist of voltage-, calcium-, and ATP-dependent ionic conductances, various ionotropic and metabotropic synaptic mechanisms, as well as neuromodulators acting on G-protein coupled receptors and second messenger systems. As described in this review, the sensorimotor responses of the respiratory network emerge through the state-dependent integration of all these building blocks. There is no known respiratory function that involves only a small number of intrinsic, synaptic, or modulatory properties. Because of the complex integration of numerous intrinsic, synaptic, and modulatory mechanisms, the respiratory network is capable of continuously adapting to changes in the external and internal environment, which makes breathing one of the most integrated behaviors. Not surprisingly, inspiration is critical not only in the control of ventilation, but also in the context of “inspiring behaviors” such as arousal of the mind and even creativity. Far-reaching implications apply also to the underlying network mechanisms, as lessons learned from the respiratory network apply to network functions in general. PMID:23720262

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.

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

Spatial distribution of airway wall displacements during breathing and bronchoconstriction measured by ultrasound elastography using finite element image registration.

PubMed

Harvey, Brian C; Lutchen, Kenneth R; Barbone, Paul E

2017-03-01

With every breath, the airways within the lungs are strained. This periodic stretching is thought to play an important role in determining airway caliber in health and disease. Particularly, deep breaths can mitigate excessive airway narrowing in healthy subjects, but this beneficial effect is absent in asthmatics, perhaps due to an inability to stretch the airway smooth muscle (ASM) embedded within an airway wall. The heterogeneous composition throughout an airway wall likely modulates the strain felt by the ASM but the magnitude of ASM strain is difficult to measure directly. In this study, we optimized a finite element image registration method to measure the spatial distribution of displacements and strains throughout an airway wall during pressure inflation within the physiological breathing range before and after induced narrowing with acetylcholine (ACh). The method was shown to be repeatable, and displacements estimated from different image sequences of the same deformation agreed to within 5.3μm (0.77%). We found the magnitude and spatial distribution of displacements were radially and longitudinally heterogeneous. The region in the middle layer of the airway experienced the largest radial strain due to a transmural pressure (Ptm) increase simulating tidal breathing and a deep inspiration (DI), while the region containing the ASM (i.e., closest to the lumen) strained least. During induced narrowing with ACh, we observed temporal longitudinal heterogeneity of the airway wall. After constriction, the displacements and strain are much smaller than the relaxed airway and the pattern of strains changed, suggesting the airway stiffened heterogeneously. Copyright © 2016 Elsevier B.V. All rights reserved.

Automated Registration of Sequential Breath-Hold Dynamic Contrast-Enhanced MRI Images: a Comparison of 3 Techniques

PubMed Central

Rajaraman, Sivaramakrishnan; Rodriguez, Jeffery J.; Graff, Christian; Altbach, Maria I.; Dragovich, Tomislav; Sirlin, Claude B.; Korn, Ronald L.; Raghunand, Natarajan

2011-01-01

Dynamic Contrast-Enhanced MRI (DCE-MRI) is increasingly in use as an investigational biomarker of response in cancer clinical studies. Proper registration of images acquired at different time-points is essential for deriving diagnostic information from quantitative pharmacokinetic analysis of these data. Motion artifacts in the presence of time-varying intensity due to contrast-enhancement make this registration problem challenging. DCE-MRI of chest and abdominal lesions is typically performed during sequential breath-holds, which introduces misregistration due to inconsistent diaphragm positions, and also places constraints on temporal resolution vis-à-vis free-breathing. In this work, we have employed a computer-generated DCE-MRI phantom to compare the performance of two published methods, Progressive Principal Component Registration and Pharmacokinetic Model-Driven Registration, with Sequential Elastic Registration (SER) to register adjacent time-sample images using a published general-purpose elastic registration algorithm. In all 3 methods, a 3-D rigid-body registration scheme with a mutual information similarity measure was used as a pre-processing step. The DCE-MRI phantom images were mathematically deformed to simulate misregistration which was corrected using the 3 schemes. All 3 schemes were comparably successful in registering large regions of interest (ROIs) such as muscle, liver, and spleen. SER was superior in retaining tumor volume and shape, and in registering smaller but important ROIs such as tumor core and tumor rim. The performance of SER on clinical DCE-MRI datasets is also presented. PMID:21531108

Highly accelerated single breath-hold noncontrast thoracic MRA: evaluation in a clinical population.

PubMed

Lim, Ruth P; Winchester, Priscilla A; Bruno, Mary T; Xu, Jian; Storey, Pippa; McGorty, Kellyanne; Sodickson, Daniel K; Srichai, Monvadi B

2013-03-01

The objective of this study was to evaluate the performance of a highly accelerated breath-hold 3-dimensional noncontrast-enhanced steady-state free precession thoracic magnetic resonance angiography (NC-MRA) technique in a clinical population, including assessment of image quality, aortic dimensions, and aortic pathology, compared with electrocardiographically gated gadolinium-enhanced MRA (Gd-MRA). After approval from the institution board and informed consent were obtained, 30 patients (22 men; mean age, 53.4 years) with known or suspected aortic pathology were imaged with NC-MRA followed by Gd-MRA at a single examination at 1.5 T. Images were made anonymous and reviewed by 2 readers for aortic pathology and diagnostic confidence on a 5-point scale (1, worst; 5, best) on a patient basis. Image quality and artifacts were also evaluated in 10 vascular segments: aortic annulus, sinuses of Valsalva, sinotubular junction, ascending aorta, aortic arch, descending aorta, diaphragmatic aorta, great vessel origins, and the left main and right coronary artery origins. Finally, aortic dimensions were measured in each of the 7 aortic segments. The Wilcoxon signed rank test was used to compare diagnostic confidence, image quality, and artifact scores between NC-MRA and Gd-MRA. The paired Student t test and Bland-Altman analysis were used for comparison of aortic dimensions. All patients completed NC-MRA and Gd-MRA successfully. Vascular pathologic findings were concordant with Gd-MRA in 29 of 30 (96.7%) patients and 28 of 30 (93.3%) patients for readers 1 and 2, respectively, with high diagnostic confidence (mean [SD], 4.35 [0.77]) not significantly different from Gd-MRA (4.38 [0.64]; P = 0.74). The image quality and artifact scores were comparable with Gd-MRA in most vascular segments. Notable differences were observed at the ascending aorta, where Gd-MRA had superior image quality (4.13 [0.73]) compared with NC-MRA (3.80 [0.88]; P = 0.028), and at the coronary artery

Changes in breathing pattern in the normal horse at rest up to age one year.

PubMed

Koterba, A M; Wozniak, J A; Kosch, P C

1995-07-01

Changes in pattern of airflow, sequence of respiratory muscle activation and generated pressures were measured serially in a group of foals during the first year post partum, in order to describe the maturation of the equine breathing pattern. In neonatal foals, inspiration and expiration were both primarily active and airflow pattern was essentially monophasic. By age 1 year, foals displayed essentially the same breathing pattern previously described in adult horses, utilising a combination of active and passive inspiration and expiration to breathe around, rather than from, the relaxation volume of the respiratory system (Vrx). A strong temporal relationship during growth was found between the timing of changes observed in airflow pattern and in the neuromuscular strategy of breathing. The transition to the adult breathing pattern appeared to involve a time delay in activation of both inspiratory and expiratory muscle groups, establishing a passive and active component to both inspiration and expiration. Throughout the study period, concurrent with the increase in delay of abdominal muscle activation, the expiratory flow pattern became progressively more biphasic in appearance. The time of appearance of a consistent biphasic inspiratory flow pattern was considerably later, at approximately age 1 year and coincided with the appearance of a delay in inspiratory muscle activation. From our results, we conclude that the transition from the neonatal to the adult breathing strategy in the horse appears not to be induced by the time course of chest wall stiffening during maturation. While changes in relative body proportions and size of abdominal contents during growth may influence the transition in breathing, our results also indicate that respiratory control mechanisms play an essential role in the expression of the polyphasic breathing pattern.

Prediction of pharmacologically induced baroreflex sensitivity from local time and frequency domain indices of R-R interval and systolic blood pressure signals obtained during deep breathing.

PubMed

Arica, Sami; Firat Ince, N; Bozkurt, Abdi; Tewfik, Ahmed H; Birand, Ahmet

2011-07-01

Pharmacological measurement of baroreflex sensitivity (BRS) is widely accepted and used in clinical practice. Following the introduction of pharmacologically induced BRS (p-BRS), alternative assessment methods eliminating the use of drugs were in the center of interest of the cardiovascular research community. In this study we investigated whether p-BRS using phenylephrine injection can be predicted from non-pharmacological time and frequency domain indices computed from electrocardiogram (ECG) and blood pressure (BP) data acquired during deep breathing. In this scheme, ECG and BP data were recorded from 16 subjects in a two-phase experiment. In the first phase the subjects performed irregular deep breaths and in the second phase the subjects received phenylephrine injection. From the first phase of the experiment, a large pool of predictors describing the local characteristic of beat-to-beat interval tachogram (RR) and systolic blood pressure (SBP) were extracted in time and frequency domains. A subset of these indices was selected using twelve subjects with an exhaustive search fused with a leave one subject out cross validation procedure. The selected indices were used to predict the p-BRS on the remaining four test subjects. A multivariate regression was used in all prediction steps. The algorithm achieved best prediction accuracy with only two features extracted from the deep breathing data, one from the frequency and the other from the time domain. The normalized L2-norm error was computed as 22.9% and the correlation coefficient was 0.97 (p=0.03). These results suggest that the p-BRS can be estimated from non-pharmacological indices computed from ECG and invasive BP data related to deep breathing. Copyright © 2011 Elsevier Ltd. All rights reserved.

Impact of changes in inspired oxygen and carbon dioxide on respiratory instability in the lamb.

PubMed

Wilkinson, Malcolm H; Sia, Kah-Ling; Skuza, Elizabeth M; Brodecky, Vojta; Berger, Philip J

2005-02-01

We examined the effect of hypoxia and hypercapnia administered during deliberately induced periodic breathing (PB) in seven lambs following posthyperventilation apnea. Based on our theoretical analysis, the sensitivity or loop gain (LG) of the respiratory control system of the lamb is directly proportional to the difference between alveolar PO2 and inspired PO2. This analysis indicates that during PB, when by necessity LG is >1, replacement of the inspired gas with one of reduced PO2 lowers LG; if we made inspired PO2 approximate alveolar PO2, we predict that LG would be approximately zero and breathing would promptly stabilize. In six lambs, we switched the inspired gas from an inspiratory oxygen fraction of 0.4 to one of 0.12 during an epoch of PB; PB was immediately suppressed, supporting the view that the peripheral chemoreceptors play a pivotal role in the genesis and control of unstable breathing in the lamb. In the six lambs in which we administered hypercapnic gas during PB, breathing instability was also suppressed, but only after a considerable time lag, indicating the CO2 effect is likely to have been mediated through the central chemoreceptors. When we simulated both interventions in a published model of the adult respiratory controller, PB was immediately suppressed by CO2 inhalation and exacerbated by inhalation of hypoxic gas. These fundamentally different responses in lambs and adult humans demonstrate that PB has differing underlying mechanisms in the two species.

Hypoxic cardiorespiratory reflexes in the facultative air-breathing fish jeju (Hoplerythrinus unitaeniatus): role of branchial O2 chemoreceptors.

PubMed

Lopes, Jane Mello; Boijink, Cheila de Lima; Florindo, Luiz Henrique; Leite, Cleo Alcantara Costa; Kalinin, Ana Lúcia; Milsom, William K; Rantin, Francisco Tadeu

2010-08-01

In one series of experiments, heart frequency (f (H)), blood pressure (P (a)), gill ventilation frequency (f ( R )), ventilation amplitude (V (AMP)) and total gill ventilation (V (TOT)) were measured in intact jeju (Hoplerythrinus unitaeniatus) and jeju with progressive denervation of the branchial branches of cranial nerves IX (glossopharyngeal) and X (vagus) without access to air. When these fish were submitted to graded hypoxia (water PO(2) approximately 140, normoxia to 17 mmHg, severe hypoxia), they increased f ( R ), V (AMP), V (TOT) and P (a) and decreased f (H). In a second series of experiments, air-breathing frequency (f (RA)), measured in fish with access to the surface, increased with graded hypoxia. In both series, bilateral denervation of all gill arches eliminated the responses to graded hypoxia. Based on the effects of internal (caudal vein, 150 microg NaCN in 0.2 mL saline) and external (buccal) injections of NaCN (500 microg NaCN in 1.0 mL water) on f (R), V (AMP), V (TOT), P (a) and f (H) we conclude that the O(2) receptors involved in eliciting changes in gill ventilation and associated cardiovascular responses are present on all gill arches and monitor the O(2) levels of both inspired water and blood perfusing the gills. We also conclude that air breathing arises solely from stimulation of branchial chemoreceptors and support the hypothesis that internal hypoxaemia is the primary drive to air breathing.

WE-DE-209-04: 3D Surface Image-Guided

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

Tang, X.

Breast radiation therapy is associated with some risk of lung toxicity as well as cardiac toxicity for left-sided cases. Radiation doses to the lung and heart can be reduced by using the deep inspiration breath hold (DIBH) technique, in which the patient is simulated and treated during the deep inspiration phase of the breathing cycle. During DIBH, the heart is usually displaced posteriorly, inferiorly, and to the right, effectively expanding the distance between the heart and the breast/chest wall. As a result, the distance between the medial treatment field border and heart/lung is increased. Also, in a majority of DIBHmore » patients, the air drawn into the thoracic cavity increases the total lung volume. The DIBH was discussed by an AAPM Task Group 10 years ago in the AAPM TG 76 report. However, DIBH is still not the standard of care in many clinics, which may be partially due to challenges associated with its implementation. Therefore, this seccion will focus primarily on how to clinically implement four different DIBH techniques: (1) Active Breathing Control, (2) Spirometric Motion Management, (3) 3D Surface Image-Guided, and (4) Self-held Breath Control with Respiratory Monitoring and Feedback Guidance. Learning Objectives: Describe the physical displacement of the heart and the change in lung volume during DIBH and discuss dosimetric consequences of those changes. Provide an overview of the technical aspects. Describe work flow for patient simulation and treatment. Give an overview of commissioning and routine. Provide practical tips for clinical implementation.« less

WE-DE-209-01: Dosimetric Benefits of DIBH

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

Howell, R.

Breast radiation therapy is associated with some risk of lung toxicity as well as cardiac toxicity for left-sided cases. Radiation doses to the lung and heart can be reduced by using the deep inspiration breath hold (DIBH) technique, in which the patient is simulated and treated during the deep inspiration phase of the breathing cycle. During DIBH, the heart is usually displaced posteriorly, inferiorly, and to the right, effectively expanding the distance between the heart and the breast/chest wall. As a result, the distance between the medial treatment field border and heart/lung is increased. Also, in a majority of DIBHmore » patients, the air drawn into the thoracic cavity increases the total lung volume. The DIBH was discussed by an AAPM Task Group 10 years ago in the AAPM TG 76 report. However, DIBH is still not the standard of care in many clinics, which may be partially due to challenges associated with its implementation. Therefore, this seccion will focus primarily on how to clinically implement four different DIBH techniques: (1) Active Breathing Control, (2) Spirometric Motion Management, (3) 3D Surface Image-Guided, and (4) Self-held Breath Control with Respiratory Monitoring and Feedback Guidance. Learning Objectives: Describe the physical displacement of the heart and the change in lung volume during DIBH and discuss dosimetric consequences of those changes. Provide an overview of the technical aspects. Describe work flow for patient simulation and treatment. Give an overview of commissioning and routine. Provide practical tips for clinical implementation.« less

WE-DE-209-03: Spirometric Motion Management System

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

Hadley, S.

Breast radiation therapy is associated with some risk of lung toxicity as well as cardiac toxicity for left-sided cases. Radiation doses to the lung and heart can be reduced by using the deep inspiration breath hold (DIBH) technique, in which the patient is simulated and treated during the deep inspiration phase of the breathing cycle. During DIBH, the heart is usually displaced posteriorly, inferiorly, and to the right, effectively expanding the distance between the heart and the breast/chest wall. As a result, the distance between the medial treatment field border and heart/lung is increased. Also, in a majority of DIBHmore » patients, the air drawn into the thoracic cavity increases the total lung volume. The DIBH was discussed by an AAPM Task Group 10 years ago in the AAPM TG 76 report. However, DIBH is still not the standard of care in many clinics, which may be partially due to challenges associated with its implementation. Therefore, this seccion will focus primarily on how to clinically implement four different DIBH techniques: (1) Active Breathing Control, (2) Spirometric Motion Management, (3) 3D Surface Image-Guided, and (4) Self-held Breath Control with Respiratory Monitoring and Feedback Guidance. Learning Objectives: Describe the physical displacement of the heart and the change in lung volume during DIBH and discuss dosimetric consequences of those changes. Provide an overview of the technical aspects. Describe work flow for patient simulation and treatment. Give an overview of commissioning and routine. Provide practical tips for clinical implementation.« less

Breathing strategy of the adult horse (Equus caballus) at rest.

PubMed

Koterba, A M; Kosch, P C; Beech, J; Whitlock, T

1988-01-01

To investigate the mechanism underlying the polyphasic airflow pattern of the equine species, we recorded airflow, tidal volum, rib cage and abdominal motion, and the sequence of activation of the diaphragm, intercostal, and abdominal muscles during quiet breathing in nine adult horses standing at rest. In addition, esophageal, abdominal, and transdiaphragmatic pressures were simultaneously recorded using balloon-tipped catheters. Analysis of tidal flow-volume loops showed that, unlike humans, the horse at rest breathes around, rather than from, the relaxed volume of the respiratory system (Vrx). Analysis of the pattern of electromyographic activities and changes in generated pressures during the breathing cycle indicate that the first part of expiration is passive, as in humans, with deflation toward Vrx, but subsequent abdominal activity is responsible for a second phase of expiration: active deflation to below Vrx. From this end-expiratory volume, passive inflation occurs toward Vrx, followed by a second phase of inspiration: active inflation to above Vrx, brought about by inspiratory muscle contraction. Under these conditions the abdominal muscles appear to share the principal pumping duties with the diaphragm. Adoption of this breathing strategy by the horse may relate to its peculiar thoracoabdominal anatomic arrangement and to its very low passive chest wall compliance. We conclude that there is a passive and active phase to both inspiration and expiration due to the coordinated action of the respiratory pump muscles responsible for the resting adult horse's biphasic inspiratory and expiratory airflow pattern. This unique breathing pattern perhaps represents a strategy of minimizing the high elastic work of breathing in this species, at least at resting breathing frequencies.

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).

MO-FG-BRA-09: Towards an Optimal Breath-Holding Procedure for Radiotherapy: Differences in Organ Motion During Inhalation and Exhalation Breath-Holds

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

Lens, E; Gurney-Champion, O; Horst, A van der

Purpose: Breath-holding (BH) is often used to reduce organ motion during radiotherapy. The aim of this study was to determine the differences in pancreatic and diaphragmatic motion during BH between inhalation and exhalation BHs with variable lung volumes and to investigate whether motion increases/decreases during BH. Methods: Sixteen healthy volunteers were asked to perform four different 60-second BHs, from fully inflated to fully deflated lungs (i.e. lung volumes of: 100%, ∼70%, ∼30% and 0% of inspiratory capacity) three times (total of 192 BHs). During each BH, we obtained single-slice (coronal) magnetic-resonance scans with spatial resolution 0.93×0.93×8.0 mm3 and temporal resolutionmore » 0.6 s. We used 2-dimensional image correlation to obtain the motion of pancreatic head and diaphragm during BH. Motion magnitude in inferior-superior direction was obtained by determining the maximum displacement during BH. Results: Pancreatic and diaphragmatic drifts occurred during BH and were mostly in the superior direction. We observed significantly smaller pancreatic and diaphragmatic motion magnitudes in inferior-superior direction during exhalation BHs (BH{sub 30%} and BH{sub 0%}) compared to inhalation BHs (BH{sub 100%} and BH{sub 70%}). The mean motion magnitudes of the pancreatic head were 7.0, 6.5, 4.4 and 4.2 mm during BH{sub 100%}, BH{sub 70%}, BH{sub 30%} and BH{sub 0%}, respectively, and mean BH durations were 59.9, 59.1, 59.0 and 52.7 s. For the diaphragm, mean motion magnitudes were 9.8, 9.0, 5.6 and 4.3 mm, respectively. When considering 30-second BHs, as often used in the clinic, the motion was most pronounced during the first 10 s and excluding these from the analysis (yielding an effective BH period of 20 s) significantly reduced (P≤0.002) organ motion. Conclusion: Organ motion was significantly smaller during exhalation BHs compared to inhalation BHs. Also, motion was largest at the start of BH. Hence, waiting for 10 s may significantly

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

Inhomogeneity of pulmonary perfusion during sustained microgravity

NASA Technical Reports Server (NTRS)

Prisk, G. Kim; Guy, Harold J. B.; Elliott, Ann R.; West, John B.

1994-01-01

The effects of gravity on the inhomogeneity of pulmonary perfusion in man were studied by performing hyperventilation-breathhold single-breath measurements before, during and after 9 days of continuous exposure to microgravity. In microgravity the indicators of inhomogeneity of perfusion, especially the size of cardiogenic oscillations in expired CO2 and the height of phase 4, were both markedly reduced. Cardiogenic oscillations were reduced to approximately 60 of their preflight standing size, while the height of phase 4 was between 0 and -8% (a terminal fall became a small terminal rise) of preflights standing. The terminal change in CO2 was nearly abolished in microgravity indicating more uniformity of blood flow between lung units that close at the end of expiration and units that remain open. This may result from the disappearance of gravity-dependent topographical inequality of blood flow. The residual cardiographic oscillations in expired CO2 imply a persisting inhomogeneity of perfusion in the absence of gravity at a level larger than acinar.

Effects of Cold Therapy on Pain and Breathing Exercises Among Median Sternotomy Patients.

PubMed

Zencir, Gülbanu; Eser, Ismet

2016-12-01

The most painful activities during the days following cardiac surgery are coughing and deep breathing exercises. Cold therapy is an effective nonpharmacological method that decreases the pain during coughing and mobilization. In this study, the effects of cold therapy on pain and breathing exercises among patients with median sternotomy following cardiac surgery were investigated in a randomized crossover clinical trial. Data were collected from patients with median sternotomy (N = 34) in the first two postoperative days. Because of the crossover design of the study, each patient was taken as a simultaneous control. Gel pack application was used as the cold therapy. Patients underwent four episodes of deep breathing and coughing exercises using an incentive spirometer (volumetric). Patients were evaluated according to the visual analogue scale for pain intensity before and after deep breathing and coughing exercise sessions. The pain score was 3.44 ± 2.45 at baseline for deep breathing and coughing exercises on the first day. The reported postoperative pain in the gel-pack group was not significantly different before and after the deep breathing and coughing exercises, but it significantly increased in the no-gel-pack group (p < .001). Although the interaction between the treatment and time was significant (partial eta-squared: .09), the gel-pack group had a lower change in average pain levels. This interaction was not significant in terms of spirometric values. In conclusion, cold therapy had a positive effect on pain management in the early period of post-cardiac surgery but was not effective for the pain associated with breathing exercises. Copyright © 2016 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

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.

[Evaluation of benefits of the course of positive pressure breathing training on exercise performance].

PubMed

Medvedev, D V; Gorbaneva, E P; Iumatova, S N; Kuznetsova, T Iu; Solopov, I N; Katuntsev, V P

2007-01-01

The purpose was to evaluate effects of muscle training combined with positive pressure breathing on exercise performance of 16 runners at the age of 18-20. All subjects had the first or second-class sport qualification. The 4-wk. training course for the experimental group (n=11) included 20-25% of exercises performed in an aperture mask creating an inspiration-expiration resistance of 8-10 mm H2O. The control group (n=5) worked on the same training course but w/o positive pressure breathing. The course began and ended with the PWC170 test in order to evaluate exercise performance. Indices of external respiration and gas exchange were determined on metabolograph Ergooxyscreen (Jaeger) and lung-tester Spirosift-3000 (Fukuda). Inspiration and expiration force of the breathing muscles (mm Hg) was measured isometrically with the help of a pneumomanometer. Heart rate was calculated from ECG R-R intervals. It was stated that positive pressure breathing during muscle training increases significantly sportsmen's exercise performance due to growth of the body spare capacities, and optimization of the body systems dependence structure and efficiency.

Occult pulmonary embolism: a common occurrence in deep venous thrombosis

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

Dorfman, G.S.; Cronan, J.J.; Tupper, T.B.

1987-02-01

Ventilation-perfusion scans were used in a prospective study to determine the prevalence of occult pulmonary embolus in proven deep venous thrombosis. Fifty-eight patients without symptoms of pulmonary embolism, but with venographically proven deep venous thrombosis, were subjected to chest radiographs, /sup 99m/Tc macroaggregated-albumin perfusion scans, and /sup 133/Xe ventilation scans. Of the 49 patients with deep venous thrombosis proximal to the calf veins, 17 (35%) had high-probability scans. Of all 58 patients, only 12 (21%) had normal scans. When the study population was compared with a group of 430 patients described in reports of pulmonary perfusion in asymptomatic persons, amore » significantly higher percentage of high-probability scans was found in the study population with deep venous thrombosis. Baseline ventilation-perfusion lung scanning is valuable for patients with proven above-knee deep venous thrombosis.« less

Assessment of regional lung functional impairment with co-registered respiratory-gated ventilation/perfusion SPET-CT images: initial experiences.

PubMed

Suga, Kazuyoshi; Yasuhiko, Kawakami; Zaki, Mohammed; Yamashita, Tomio; Seto, Aska; Matsumoto, Tsuneo; Matsunaga, Naofumi

2004-02-01

In this study, respiratory-gated ventilation and perfusion single-photon emission tomography (SPET) were used to define regional functional impairment and to obtain reliable co-registration with computed tomography (CT) images in various lung diseases. Using a triple-headed SPET unit and a physiological synchroniser, gated perfusion SPET was performed in a total of 78 patients with different pulmonary diseases, including metastatic nodules (n = 15); in 34 of these patients, it was performed in combination with gated technetium-99m Technegas SPET. Projection data were acquired using 60 stops over 120 degrees for each detector. Gated end-inspiration and ungated images were reconstructed from 1/8 data centered at peak inspiration for each regular respiratory cycle and full respiratory cycle data, respectively. Gated images were registered with tidal inspiration CT images using automated three-dimensional (3D) registration software. Registration mismatch was assessed by measuring 3D distance of the centroid of the nine selected round perfusion-defective nodules. Gated SPET images were completed within 29 min, and increased the number of visible ventilation and perfusion defects by 9.7% and 17.2%, respectively, as compared with ungated images; furthermore, lesion-to-normal lung contrast was significantly higher on gated SPET images. In the nine round perfusion-defective nodules, gated images yielded a significantly better SPET-CT match compared with ungated images (4.9 +/- 3.1 mm vs 19.0 +/- 9.1 mm, P<0.001). The co-registered SPET-CT images allowed accurate perception of the location and extent of each ventilation/perfusion defect on the underlying CT anatomy, and characterised the pathophysiology of the various diseases. By reducing respiratory motion effects and enhancing perfusion/ventilation defect clarity, gated SPET can provide reliable co-registered images with CT images to accurately characterise regional functional impairment in various lung diseases.

Non-Contact Detection of Breathing Using a Microwave Sensor

PubMed Central

Dei, Devis; Grazzini, Gilberto; Luzi, Guido; Pieraccini, Massimiliano; Atzeni, Carlo; Boncinelli, Sergio; Camiciottoli, Gianna; Castellani, Walter; Marsili, Massimo; Dico, Juri Lo

2009-01-01

In this paper the use of a continuous-wave microwave sensor as a non-contact tool for quantitative measurement of respiratory tidal volume has been evaluated by experimentation in seventeen healthy volunteers. The sensor working principle is reported and several causes that can affect its response are analyzed. A suitable data processing has been devised able to reject the majority of breath measurements taken under non suitable conditions. Furthermore, a relationship between microwave sensor measurements and volume inspired and expired at quiet breathing (tidal volume) has been found. PMID:22574033

Sensing the effects of mouth breathing by using 3-tesla MRI

NASA Astrophysics Data System (ADS)

Park, Chan-A.; Kang, Chang-Ki

2017-06-01

We investigated the effects of mouth breathing and typical nasal breathing on brain function by using blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI). The study had two parts: the first test was a simple contrast between mouth and nasal breathing, and the second test involved combined breathing modes, e.g., mouth inspiration and nasal expiration. Eleven healthy participants performed the combined breathing task while undergoing 3T fMRI. In the group-level analysis, contrast images acquired by using an individual participantlevel analysis were processed using the one-sample t test. We also conducted a region-of-interest analysis comparing signal intensity changes between the breathing modes; the region was selected using an automated anatomical labeling map. The results demonstrated that the BOLD signal in the hippocampus and brainstem was significantly decreased in mouth breathing relative to nasal breathing. On the other hand, both the precentral and postcentral gyri showed activation that was more significant in mouth breathing compared to nasal breathing. This study suggests that the BOLD activity patterns between mouth and nasal breathing may be induced differently, especially in the hippocampus, which could provide clues to explain the effects on brain cognitive function due to mouth breathing.

Breathing is affected by dopamine D2-like receptors in the basolateral amygdala.

PubMed

Sugita, Toshihisa; Kanamaru, Mitsuko; Iizuka, Makito; Sato, Kanako; Tsukada, Setsuro; Kawamura, Mitsuru; Homma, Ikuo; Izumizaki, Masahiko

2015-04-01

The precise mechanisms underlying how emotions change breathing patterns remain unclear, but dopamine is a candidate neurotransmitter in the process of emotion-associated breathing. We investigated whether basal dopamine release occurs in the basolateral amygdala (BLA), where sensory-related inputs are received and lead to fear or anxiety responses, and whether D1- and D2-like receptor antagonists affect breathing patterns and dopamine release in the BLA. Adult male mice (C57BL/6N) were perfused with artificial cerebrospinal fluid, a D1-like receptor antagonist (SCH 23390), or a D2-like receptor antagonist ((S)-(-)-sulpiride) through a microdialysis probe in the BLA. Respiratory variables were measured using a double-chamber plethysmograph. Dopamine release was measured by an HPLC. Perfusion of (S)-(-)-sulpiride in the BLA, not SCH 23390, specifically decreased respiratory rate without changes in local release of dopamine. These results suggest that basal dopamine release in the BLA, at least partially, increases respiratory rates only through post-synaptic D2-like receptors, not autoreceptors, which might be associated with emotional responses. Copyright © 2014 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.

Aortic arch reconstruction: deep and moderate hypothermic circulatory arrest with selective antegrade cerebral perfusion.

PubMed

Wu, YanWen; Xiao, LiQiong; Yang, Ting; Wang, Lei; Chen, Xin

2017-07-01

To compare the effects of moderate and deep hypothermic circulatory arrest (DHCA) with selective antegrade cerebral perfusion (SACP) during aortic arch surgery in adult patients and to offer the evidence for the detection of the temperature which provides best brain protection in the subjects who accept aortic arch reconstruction surgery. A total of 109 patients undergoing surgery of the aortic arch were divided into the moderate hypothermic circulatory arrest group (Group I) and the deep hypothermic circulatory arrest group (Group II). We recorded the data of the patients and their cardiopulmonary bypass (CPB) time, aortic clamping time, SACP time and postoperative anesthetized recovery time, tracheal intubation time, time in the intensive care unit (ICU) and postoperative neurologic dysfunction. Patient characteristics were similar in the two groups. There were four patients who died in Group II and 1 patient in Group I. There were no significant differences in aortic clamping time of each group (111.4±58.4 vs. 115.9±16.2) min; SACP time (27.4±5.9 vs. 23.5±6.1) min of the moderate hypothermic circulatory arrest group and the deep hypothermic circulatory arrest group; there were significant differences in cardiopulmonary bypass time (207.4±20.9 vs. 263.8±22.6) min, postoperative anesthetized recovery time (19.0±11.1 vs. 36.8±25.3) hours, extubation time (46.4±15.1 vs. 64.4±6.0) hours; length of stay in the intensive care unit (ICU) (4.7±1.7 vs. 8±2.3) days and postoperative neurologic dysfunction in the two groups. Compared to deep hypothermic circulatory arrest, moderate hypothermic circulatory arrest can provide better brain protection and achieve good clinical results.

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.

Is moderate hypothermic circulatory arrest with selective antegrade cerebral perfusion superior to deep hypothermic circulatory arrest in elective aortic arch surgery?

PubMed

Poon, Shi Sum; Estrera, Anthony; Oo, Aung; Field, Mark

2016-09-01

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether moderate hypothermia circulatory arrest with selective antegrade cerebral perfusion (SACP) is more beneficial than deep hypothermic circulatory arrest in elective aortic arch surgery. Altogether, 1028 papers were found using the reported search, of which 6 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. There were four retrospective observational studies, one prospective randomized controlled trial and one meta-analysis study. There were no local or neuromuscular complications related to axillary arterial cannulation reported. In the elective setting, four studies showed that the in-hospital mortality for moderate hypothermia is consistently low, ranging from 1.0 to 4.3%. In a large series of hemiarch replacement comparing 682 cases of deep hypothermia with 94 cases of moderate hypothermia with SACP, 20 cases (2.8%) of permanent neurological deficit were reported, compared to 3 cases (3.2%) in moderate hypothermia. Three observational studies and a meta-analysis study did not identify an increased risk of postoperative renal failure and dialysis following either deep or moderate hypothermia although a higher incidence of stroke was reported in the meta-analysis study with deep hypothermia (12.7 vs 7.3%). Longer cardiopulmonary bypass time and circulatory arrest time were reported in four studies for deep hypothermia, suggesting an increased time required for systemic cooling and rewarming in that group. Overall, these findings suggested that in elective aortic arch surgery, moderate hypothermia with selective antegrade cerebral perfusion adapted to the duration of circulatory arrest can be performed safely with acceptable mortality and morbidity outcomes. The risk of spinal cord

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)

CO2-evoked release of PGE2 modulates sighs and inspiration as demonstrated in brainstem organotypic culture

PubMed Central

Forsberg, David; Horn, Zachi; Tserga, Evangelia; Smedler, Erik; Silberberg, Gilad; Shvarev, Yuri; Kaila, Kai; Uhlén, Per; Herlenius, Eric

2016-01-01

Inflammation-induced release of prostaglandin E2 (PGE2) changes breathing patterns and the response to CO2 levels. This may have fatal consequences in newborn babies and result in sudden infant death. To elucidate the underlying mechanisms, we present a novel breathing brainstem organotypic culture that generates rhythmic neural network and motor activity for 3 weeks. We show that increased CO2 elicits a gap junction-dependent release of PGE2. This alters neural network activity in the preBötzinger rhythm-generating complex and in the chemosensitive brainstem respiratory regions, thereby increasing sigh frequency and the depth of inspiration. We used mice lacking eicosanoid prostanoid 3 receptors (EP3R), breathing brainstem organotypic slices and optogenetic inhibition of EP3R+/+ cells to demonstrate that the EP3R is important for the ventilatory response to hypercapnia. Our study identifies a novel pathway linking the inflammatory and respiratory systems, with implications for inspiration and sighs throughout life, and the ability to autoresuscitate when breathing fails. DOI: http://dx.doi.org/10.7554/eLife.14170.001 PMID:27377173

Breathing and Singing: Objective Characterization of Breathing Patterns in Classical Singers

PubMed Central

Salomoni, Sauro; van den Hoorn, Wolbert; Hodges, Paul

2016-01-01

Singing involves distinct respiratory kinematics (i.e. movements of rib cage and abdomen) to quiet breathing because of different demands on the respiratory system. Professional classical singers often advocate for the advantages of an active control of the abdomen on singing performance. This is presumed to prevent shortening of the diaphragm, elevate the rib cage, and thus promote efficient generation of subglottal pressure during phonation. However, few studies have investigated these patterns quantitatively and inter-subject variability has hindered the identification of stereotypical patterns of respiratory kinematics. Here, seven professional classical singers and four untrained individuals were assessed during quiet breathing, and when singing both a standard song and a piece of choice. Several parameters were extracted from respiratory kinematics and airflow, and principal component analysis was used to identify typical patterns of respiratory kinematics. No group differences were observed during quiet breathing. During singing, both groups adapted to rhythmical constraints with decreased time of inspiration and increased peak airflow. In contrast to untrained individuals, classical singers used greater percentage of abdominal contribution to lung volume during singing and greater asynchrony between movements of rib cage and abdomen. Classical singers substantially altered the coordination of rib cage and abdomen during singing from that used for quiet breathing. Despite variations between participants, principal component analysis revealed consistent pre-phonatory inward movements of the abdominal wall during singing. This contrasted with untrained individuals, who demonstrated synchronous respiratory movements during all tasks. The inward abdominal movements observed in classical singers elevates intra-abdominal pressure and may increase the length and the pressure-generating capacity of rib cage expiratory muscles for potential improvements in voice

Breathing and Singing: Objective Characterization of Breathing Patterns in Classical Singers.

PubMed

Salomoni, Sauro; van den Hoorn, Wolbert; Hodges, Paul

2016-01-01

Singing involves distinct respiratory kinematics (i.e. movements of rib cage and abdomen) to quiet breathing because of different demands on the respiratory system. Professional classical singers often advocate for the advantages of an active control of the abdomen on singing performance. This is presumed to prevent shortening of the diaphragm, elevate the rib cage, and thus promote efficient generation of subglottal pressure during phonation. However, few studies have investigated these patterns quantitatively and inter-subject variability has hindered the identification of stereotypical patterns of respiratory kinematics. Here, seven professional classical singers and four untrained individuals were assessed during quiet breathing, and when singing both a standard song and a piece of choice. Several parameters were extracted from respiratory kinematics and airflow, and principal component analysis was used to identify typical patterns of respiratory kinematics. No group differences were observed during quiet breathing. During singing, both groups adapted to rhythmical constraints with decreased time of inspiration and increased peak airflow. In contrast to untrained individuals, classical singers used greater percentage of abdominal contribution to lung volume during singing and greater asynchrony between movements of rib cage and abdomen. Classical singers substantially altered the coordination of rib cage and abdomen during singing from that used for quiet breathing. Despite variations between participants, principal component analysis revealed consistent pre-phonatory inward movements of the abdominal wall during singing. This contrasted with untrained individuals, who demonstrated synchronous respiratory movements during all tasks. The inward abdominal movements observed in classical singers elevates intra-abdominal pressure and may increase the length and the pressure-generating capacity of rib cage expiratory muscles for potential improvements in voice

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

CRUSTAL FAILURE DURING BINARY INSPIRAL

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

Penner, A. J.; Andersson, N.; Jones, D. I.

2012-04-20

We present the first fully relativistic calculations of the crustal strain induced in a neutron star by a binary companion at the late stages of inspiral, employing realistic equations of state for the fluid core and the solid crust. We show that while the deep crust is likely to fail only shortly before coalescence, there is a large variation in elastic strain, with the outermost layers failing relatively early on in the inspiral. We discuss the significance of the results for both electromagnetic and gravitational-wave astronomy.

Fully automated motion correction in first-pass myocardial perfusion MR image sequences.

PubMed

Milles, Julien; van der Geest, Rob J; Jerosch-Herold, Michael; Reiber, Johan H C; Lelieveldt, Boudewijn P F

2008-11-01

This paper presents a novel method for registration of cardiac perfusion magnetic resonance imaging (MRI). The presented method is capable of automatically registering perfusion data, using independent component analysis (ICA) to extract physiologically relevant features together with their time-intensity behavior. A time-varying reference image mimicking intensity changes in the data of interest is computed based on the results of that ICA. This reference image is used in a two-pass registration framework. Qualitative and quantitative validation of the method is carried out using 46 clinical quality, short-axis, perfusion MR datasets comprising 100 images each. Despite varying image quality and motion patterns in the evaluation set, validation of the method showed a reduction of the average right ventricle (LV) motion from 1.26+/-0.87 to 0.64+/-0.46 pixels. Time-intensity curves are also improved after registration with an average error reduced from 2.65+/-7.89% to 0.87+/-3.88% between registered data and manual gold standard. Comparison of clinically relevant parameters computed using registered data and the manual gold standard show a good agreement. Additional tests with a simulated free-breathing protocol showed robustness against considerable deviations from a standard breathing protocol. We conclude that this fully automatic ICA-based method shows an accuracy, a robustness and a computation speed adequate for use in a clinical environment.

Goal-directed-perfusion in neonatal aortic arch surgery.

PubMed

Cesnjevar, Robert Anton; Purbojo, Ariawan; Muench, Frank; Juengert, Joerg; Rueffer, André

2016-07-01

Reduction of mortality and morbidity in congenital cardiac surgery has always been and remains a major target for the complete team involved. As operative techniques are more and more standardized and refined, surgical risk and associated complication rates have constantly been reduced to an acceptable level but are both still present. Aortic arch surgery in neonates seems to be of particular interest, because perfusion techniques differ widely among institutions and an ideal form of a so called "total body perfusion (TBP)" is somewhat difficult to achieve. Thus concepts of deep hypothermic circulatory arrest (DHCA), regional cerebral perfusion (RCP/with cardioplegic cardiac arrest or on the perfused beating heart) and TBP exist in parallel and all carry an individual risk for organ damage related to perfusion management, chosen core temperature and time on bypass. Patient safety relies more and more on adequate end organ perfusion on cardiopulmonary bypass, especially sensitive organs like the brain, heart, kidney, liver and the gut, whereby on adequate tissue protection, temperature management and oxygen delivery should be visualized and monitored.

Validation of motion correction techniques for liver CT perfusion studies

PubMed Central

Chandler, A; Wei, W; Anderson, E F; Herron, D H; Ye, Z; Ng, C S

2012-01-01

Objectives Motion in images potentially compromises the evaluation of temporally acquired CT perfusion (CTp) data; image registration should mitigate this, but first requires validation. Our objective was to compare the relative performance of manual, rigid and non-rigid registration techniques to correct anatomical misalignment in acquired liver CTp data sets. Methods 17 data sets in patients with liver tumours who had undergone a CTp protocol were evaluated. Each data set consisted of a cine acquisition during a breath-hold (Phase 1), followed by six further sets of cine scans (each containing 11 images) acquired during free breathing (Phase 2). Phase 2 images were registered to a reference image from Phase 1 cine using two semi-automated intensity-based registration techniques (rigid and non-rigid) and a manual technique (the only option available in the relevant vendor CTp software). The performance of each technique to align liver anatomy was assessed by four observers, independently and blindly, on two separate occasions, using a semi-quantitative visual validation study (employing a six-point score). The registration techniques were statistically compared using an ordinal probit regression model. Results 306 registrations (2448 observer scores) were evaluated. The three registration techniques were significantly different from each other (p=0.03). On pairwise comparison, the semi-automated techniques were significantly superior to the manual technique, with non-rigid significantly superior to rigid (p<0.0001), which in turn was significantly superior to manual registration (p=0.04). Conclusion Semi-automated registration techniques achieved superior alignment of liver anatomy compared with the manual technique. We hope this will translate into more reliable CTp analyses. PMID:22374283

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

Bio-Inspired Controller on an FPGA Applied to Closed-Loop Diaphragmatic Stimulation

PubMed Central

Zbrzeski, Adeline; Bornat, Yannick; Hillen, Brian; Siu, Ricardo; Abbas, James; Jung, Ranu; Renaud, Sylvie

2016-01-01

Cervical spinal cord injury can disrupt connections between the brain respiratory network and the respiratory muscles which can lead to partial or complete loss of ventilatory control and require ventilatory assistance. Unlike current open-loop technology, a closed-loop diaphragmatic pacing system could overcome the drawbacks of manual titration as well as respond to changing ventilation requirements. We present an original bio-inspired assistive technology for real-time ventilation assistance, implemented in a digital configurable Field Programmable Gate Array (FPGA). The bio-inspired controller, which is a spiking neural network (SNN) inspired by the medullary respiratory network, is as robust as a classic controller while having a flexible, low-power and low-cost hardware design. The system was simulated in MATLAB with FPGA-specific constraints and tested with a computational model of rat breathing; the model reproduced experimentally collected respiratory data in eupneic animals. The open-loop version of the bio-inspired controller was implemented on the FPGA. Electrical test bench characterizations confirmed the system functionality. Open and closed-loop paradigm simulations were simulated to test the FPGA system real-time behavior using the rat computational model. The closed-loop system monitors breathing and changes in respiratory demands to drive diaphragmatic stimulation. The simulated results inform future acute animal experiments and constitute the first step toward the development of a neuromorphic, adaptive, compact, low-power, implantable device. The bio-inspired hardware design optimizes the FPGA resource and time costs while harnessing the computational power of spike-based neuromorphic hardware. Its real-time feature makes it suitable for in vivo applications. PMID:27378844

Volumetric Arterial Spin-labeled Perfusion Imaging of the Kidneys with a Three-dimensional Fast Spin Echo Acquisition.

PubMed

Robson, Philip M; Madhuranthakam, Ananth J; Smith, Martin P; Sun, Maryellen R M; Dai, Weiying; Rofsky, Neil M; Pedrosa, Ivan; Alsop, David C

2016-02-01

Renal perfusion measurements using noninvasive arterial spin-labeled (ASL) magnetic resonance imaging techniques are gaining interest. Currently, focus has been on perfusion in the context of renal transplant. Our objectives were to explore the use of ASL in patients with renal cancer, and to evaluate three-dimensional (3D) fast spin echo (FSE) acquisition, a robust volumetric imaging method for abdominal applications. We evaluate 3D ASL perfusion magnetic resonance imaging in the kidneys compared to two-dimensional (2D) ASL in patients and healthy subjects. Isotropic resolution (2.6 × 2.6 × 2.8 mm(3)) 3D ASL using segmented FSE was compared to 2D single-shot FSE. ASL used pseudo-continuous labeling, suppression of background signal, and synchronized breathing. Quantitative perfusion values and signal-to-noise ratio (SNR) were compared between 3D and 2D ASL in four healthy volunteers and semiquantitative assessments were made by four radiologists in four patients with known renal masses (primary renal cell carcinoma). Renal cortex perfusion in healthy subjects was 284 ± 21 mL/100 g/min, with test-retest repeatability of 8.8%. No significant differences were found between the quantitative perfusion value and SNR in volunteers between 3D ASL and 2D ASL, or in 3D ASL with synchronized or free breathing. In patients, semiquantitative assessment by radiologists showed no significant difference in image quality between 2D ASL and 3D ASL. In one case, 2D ASL missed a high perfusion focus in a mass that was seen by 3D ASL. 3D ASL renal perfusion imaging provides isotropic-resolution images, with comparable quantitative perfusion values and image SNR in similar imaging time to single-slice 2D ASL. Copyright © 2015 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

TU-CD-BRA-08: Single-Energy Computed Tomography-Based Pulmonary Perfusion Imaging: Proof-Of-Principle in a Canine Model

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

Yamamoto, T; Boone, J; Kent, M

Purpose: Pulmonary perfusion imaging has provided significant insights into pulmonary diseases, and can be useful in radiotherapy. The purpose of this study was to prospectively establish proof-of-principle in a canine model for single-energy CT-based perfusion imaging, which has the potential for widespread clinical implementation. Methods: Single-energy CT perfusion imaging is based on: (1) acquisition of inspiratory breath-hold CT scans before and after intravenous injection of iodinated contrast medium, (2) deformable image registration (DIR) of the two CT image data sets, and (3) subtraction of the pre-contrast image from post-contrast image, yielding a map of Hounsfield unit (HU) enhancement. These subtractionmore » image data sets hypothetically represent perfused blood volume, a surrogate for perfusion. In an IACUC-approved clinical trial, we acquired pre- and post-contrast CT scans in the prone posture for six anesthetized, mechanically-ventilated dogs. The elastix algorithm was used for DIR. The registration accuracy was quantified using the target registration errors (TREs) for 50 pulmonary landmarks in each dog. The gradient of HU enhancement between gravity-dependent (ventral) and non-dependent (dorsal) regions was evaluated to quantify the known effect of gravity, i.e., greater perfusion in ventral regions. Results: The lung volume difference between the two scans was 4.3±3.5% on average (range 0.3%–10.1%). DIR demonstrated an average TRE of 0.7±1.0 mm. HU enhancement in lung parenchyma was 34±10 HU on average and varied considerably between individual dogs, indicating the need for improvement of the contrast injection protocol. HU enhancement in ventral (gravity-dependent) regions was found to be greater than in dorsal regions. A population average ventral-to-dorsal gradient of HU enhancement was strong (R{sup 2}=0.94) and statistically significant (p<0.01). Conclusion: This canine study demonstrated relatively accurate DIR and a strong

Cardiac Side-effects From Breast Cancer Radiotherapy.

PubMed

Taylor, C W; Kirby, A M

2015-11-01

Breast cancer radiotherapy reduces the risk of cancer recurrence and death. However, it usually involves some radiation exposure of the heart and analyses of randomised trials have shown that it can increase the risk of heart disease. Estimates of the absolute risks of radiation-related heart disease are needed to help oncologists plan each individual woman's treatment. The risk for an individual woman varies according to her estimated cardiac radiation dose and her background risk of ischaemic heart disease in the absence of radiotherapy. When it is known, this risk can then be compared with the absolute benefit of the radiotherapy. At present, many UK cancer centres are already giving radiotherapy with mean heart doses of less than 3 Gy and for most women the benefits of the radiotherapy will probably far outweigh the risks. Technical approaches to minimising heart dose in breast cancer radiotherapy include optimisation of beam angles, use of multileaf collimator shielding, intensity-modulated radiotherapy, treatment in a prone position, treatment in deep inspiration (including the use of breath-hold and gating techniques), proton therapy and partial breast irradiation. The multileaf collimator is suitable for many women with upper pole left breast cancers, but for women with central or lower pole cancers, breath-holding techniques are now recommended in national UK guidelines. Ongoing work aims to identify ways of irradiating pan-regional lymph nodes that are effective, involve minimal exposure of organs at risk and are feasible to plan, deliver and verify. These will probably include wide tangent-based field-in-field intensity-modulated radiotherapy or arc radiotherapy techniques in combination with deep inspiratory breath-hold, and proton beam irradiation for women who have a high predicted heart dose from intensity-modulated radiotherapy. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Evaluation of a semiautomated lung mass calculation technique for internal dosimetry applications

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

Busse, Nathan; Erwin, William; Pan, Tinsu

2013-12-15

Purpose: The authors sought to evaluate a simple, semiautomated lung mass estimation method using computed tomography (CT) scans obtained using a variety of acquisition techniques and reconstruction parameters for mass correction of medical internal radiation dose-based internal radionuclide radiation absorbed dose estimates.Methods: CT scans of 27 patients with lung cancer undergoing stereotactic body radiation therapy treatment planning with PET/CT were analyzed retrospectively. For each patient, free-breathing (FB) and respiratory-gated 4DCT scans were acquired. The 4DCT scans were sorted into ten respiratory phases, representing one complete respiratory cycle. An average CT reconstruction was derived from the ten-phase reconstructions. Mid expiration breath-holdmore » CT scans were acquired in the same session for many patients. Deep inspiration breath-hold diagnostic CT scans of many of the patients were obtained from different scanning sessions at similar time points to evaluate the effect of contrast administration and maximum inspiration breath-hold. Lung mass estimates were obtained using all CT scan types, and intercomparisons made to assess lung mass variation according to scan type. Lung mass estimates using the FB CT scans from PET/CT examinations of another group of ten male and ten female patients who were 21–30 years old and did not have lung disease were calculated and compared with reference lung mass values. To evaluate the effect of varying CT acquisition and reconstruction parameters on lung mass estimation, an anthropomorphic chest phantom was scanned and reconstructed with different CT parameters. CT images of the lungs were segmented using the OsiriX MD software program with a seed point of about −850 HU and an interval of 1000. Lung volume, and mean lung, tissue, and air HUs were recorded for each scan. Lung mass was calculated by assuming each voxel was a linear combination of only air and tissue. The specific gravity of lung volume

Qualitative and quantitative evaluation of rigid and deformable motion correction algorithms using dual-energy CT images in view of application to CT perfusion measurements in abdominal organs affected by breathing motion

PubMed Central

Skornitzke, S; Fritz, F; Klauss, M; Pahn, G; Hansen, J; Hirsch, J; Grenacher, L; Kauczor, H-U

2015-01-01

Objective: To compare six different scenarios for correcting for breathing motion in abdominal dual-energy CT (DECT) perfusion measurements. Methods: Rigid [RRComm(80 kVp)] and non-rigid [NRComm(80 kVp)] registration of commercially available CT perfusion software, custom non-rigid registration [NRCustom(80 kVp], demons algorithm) and a control group [CG(80 kVp)] without motion correction were evaluated using 80 kVp images. Additionally, NRCustom was applied to dual-energy (DE)-blended [NRCustom(DE)] and virtual non-contrast [NRCustom(VNC)] images, yielding six evaluated scenarios. After motion correction, perfusion maps were calculated using a combined maximum slope/Patlak model. For qualitative evaluation, three blinded radiologists independently rated motion correction quality and resulting perfusion maps on a four-point scale (4 = best, 1 = worst). For quantitative evaluation, relative changes in metric values, R2 and residuals of perfusion model fits were calculated. Results: For motion-corrected images, mean ratings differed significantly [NRCustom(80 kVp) and NRCustom(DE), 3.3; NRComm(80 kVp), 3.1; NRCustom(VNC), 2.9; RRComm(80 kVp), 2.7; CG(80 kVp), 2.7; all p < 0.05], except when comparing NRCustom(80 kVp) with NRCustom(DE) and RRComm(80 kVp) with CG(80 kVp). NRCustom(80 kVp) and NRCustom(DE) achieved the highest reduction in metric values [NRCustom(80 kVp), 48.5%; NRCustom(DE), 45.6%; NRComm(80 kVp), 29.2%; NRCustom(VNC), 22.8%; RRComm(80 kVp), 0.6%; CG(80 kVp), 0%]. Regarding perfusion maps, NRCustom(80 kVp) and NRCustom(DE) were rated highest [NRCustom(80 kVp), 3.1; NRCustom(DE), 3.0; NRComm(80 kVp), 2.8; NRCustom(VNC), 2.6; CG(80 kVp), 2.5; RRComm(80 kVp), 2.4] and had significantly higher R2 and lower residuals. Correlation between qualitative and quantitative evaluation was low to moderate. Conclusion: Non-rigid motion correction improves spatial alignment of the target region and fit of CT

A wireless breathing-training support system for kinesitherapy.

PubMed

Tawa, Hiroki; Yonezawa, Yoshiharu; Maki, Hiromichi; Ogawa, Hidekuni; Ninomiya, Ishio; Sada, Kouji; Hamada, Shingo; Caldwell, W Morton

2009-01-01

We have developed a new wireless breathing-training support system for kinesitherapy. The system consists of an optical sensor, an accelerometer, a microcontroller, a Bluetooth module and a laptop computer. The optical sensor, which is attached to the patient's chest, measures chest circumference. The low frequency components of circumference are mainly generated by breathing. The optical sensor outputs the circumference as serial digital data. The accelerometer measures the dynamic acceleration force produced by exercise, such as walking. The microcontroller sequentially samples this force. The acceleration force and chest circumference are sent sequentially via Bluetooth to a physical therapist's laptop computer, which receives and stores the data. The computer simultaneously displays these data so that the physical therapist can monitor the patient's breathing and acceleration waveforms and give instructions to the patient in real time during exercise. Moreover, the system enables a quantitative training evaluation and calculation the volume of air inspired and expired by the lungs.

Usefulness of Deep Hypothermic Circulatory Arrest and Regional Cerebral Perfusion in Children

PubMed Central

Guo, Zheng; Hu, Ren-Jie; Zhu, De-Ming; Zhu, Zhong-Qun; Zhang, Hai-Bo

2013-01-01

To compare the safety and usefulness of deep hypothermic circulatory arrest (DHCA) and regional cerebral perfusion (RCP) during pediatric open heart surgery. Between January 1, 2004 and September 30, 2012, 1250 children with congenital cardiac defect underwent corrective operation with the DHCA or RCP technique in the Shanghai Children's Medical Center. Of them, 947 cases underwent the operation with the aid of DHCA (DHCA group), and 303 cases with RCP (RCP group). The mean DHCA time was 30.64±15.81 (7–63) minutes and mean RCP time was 36.18±12.86 (10–82) minutes. The mortality rate was 7.18% (68/947) and 6.60% (20/30) in two groups, respectively. The postoperative incidences of temporary and permanent neurological dysfunction were 6.23% (59/947) in the DHCA group and 2.64% (8/303) in the RCP group (p<0.01). The incidence of other complications such as low cardiac output, renal dysfunction, and lung issues are similar in both groups. RCP is a reliable technique for cerebral protection and it facilitates time-consuming corrected procedures for complex congenital cardiac defect repair procedures. PMID:24066266

A multislice single breath-hold scheme for imaging alveolar oxygen tension in humans.

PubMed

Hamedani, Hooman; Kadlecek, Stephen J; Emami, Kiarash; Kuzma, Nicholas N; Xu, Yinan; Xin, Yi; Mongkolwisetwara, Puttisarn; Rajaei, Jennia; Barulic, Amy; Wilson Miller, G; Rossman, Milton; Ishii, Masaru; Rizi, Rahim R

2012-05-01

Reliable, noninvasive, and high-resolution imaging of alveolar partial pressure of oxygen (p(A)O(2)) is a potentially valuable tool in the early diagnosis of pulmonary diseases. Several techniques have been proposed for regional measurement of p(A)O(2) based on the increased depolarization rate of hyperpolarized (3) He. In this study, we explore one such technique by applying a multislice p(A)O(2) -imaging scheme that uses interleaved-slice ordering to utilize interslice time-delays more efficiently. This approach addresses the low spatial resolution and long breath-hold requirements of earlier techniques, allowing p(A)O(2) measurements to be made over the entire human lung in 10-15 s with a typical resolution of 8.3 × 8.3 × 15.6 mm(3). PO(2) measurements in a glass syringe phantom were in agreement with independent gas analysis within 4.7 ± 4.1% (R = 0.9993). The technique is demonstrated in four human subjects (healthy nonsmoker, healthy former smoker, healthy smoker, and patient with COPD), each imaged six times on 3 different days during a 2-week span. Two independent measurements were performed in each session, consisting of 12 coronal slices. The overall p(A)O(2) mean across all subjects was 95.9 ± 12.2 Torr and correlated well with end-tidal O(2) (R = 0.805, P < 0.0001). The alveolar O(2) uptake rate was consistent with the expected range of 1-2 Torr/s. Repeatable visual features were observed in p(A)O(2) maps over different days, as were characteristic differences among the subjects and gravity-dependent effects. Copyright © 2011 Wiley Periodicals, Inc.

Influence of Ankle Active Dorsiflexion Movement Guided by Inspiration on the Venous Return From the Lower Limbs: A Prospective Study.

PubMed

Pi, Hongying; Ku, Hong'an; Zhao, Ting; Wang, Jie; Fu, Yicheng

2018-04-01

Active ankle movement is recommended intervention for preventing deep vein thrombosis effectively and easily by promoting venous return from the lower limbs. The active ankle dorsiflexion and plantar flexion movement guided by deep breathing is considered the most effective method, although outstanding problems remain, including low patient compliance and difficult motion essentials. The aims of this study were to compare the influence of different ankle active movements on venous return from the lower limbs and to suggest the optimal movement for preventing deep venous thrombosis in the lower limbs. A self-controlled study on 130 subjects was undertaken. The femoral venous hemodynamics of the left femoral vein and changes in pulse oxygen saturation and heart rate were compared among the three states of quiescent, active ankle 30° dorsiflexion movement, and active ankle 30° dorsiflexion with active plantar 45° flexion movement. The immediate master rates of the two ankle movements were examined before the study. The femoral venous hemodynamics of the left femoral vein were significantly higher in both movement states compared with the quiescent state. Moreover, no significant difference was found among the three states in terms of pulse oxygen saturation and heart rate. The immediate master rate was significantly higher in the active ankle 30° dorsiflexion movement than in the active ankle 30° dorsiflexion and active plantar 45° flexion movement. Therefore, active ankle 30° dorsiflexion movement guided by inspiration was found in this study to increase femoral venous hemodynamics, which heightened the immediate master rate but had no obvious influence on pulse oxygen saturation and heart rate. Active ankle 30° dorsiflexion movement guided by inspiration effectively promotes venous return from the lower limbs and is a better method to prevent deep vein thrombosis of the lower limbs.

Mind-body relationships in elite apnea divers during breath holding: a study of autonomic responses to acute hypoxemia

PubMed Central

Laurino, Marco; Menicucci, Danilo; Mastorci, Francesca; Allegrini, Paolo; Piarulli, Andrea; Scilingo, Enzo P.; Bedini, Remo; Pingitore, Alessandro; Passera, Mirko; L'Abbate, Antonio; Gemignani, Angelo

2011-01-01

The mental control of ventilation with all associated phenomena, from relaxation to modulation of emotions, from cardiovascular to metabolic adaptations, constitutes a psychophysiological condition characterizing voluntary breath-holding (BH). BH induces several autonomic responses, involving both autonomic cardiovascular and cutaneous pathways, whose characterization is the main aim of this study. Electrocardiogram and skin conductance (SC) recordings were collected from 14 elite divers during three conditions: free breathing (FB), normoxic phase of BH (NPBH) and hypoxic phase of BH (HPBH). Thus, we compared a set of features describing signal dynamics between the three experimental conditions: from heart rate variability (HRV) features (in time and frequency-domains and by using nonlinear methods) to rate and shape of spontaneous SC responses (SCRs). The main result of the study rises by applying a Factor Analysis to the subset of features significantly changed in the two BH phases. Indeed, the Factor Analysis allowed to uncover the structure of latent factors which modeled the autonomic response: a factor describing the autonomic balance (AB), one the information increase rate (IIR), and a latter the central nervous system driver (CNSD). The BH did not disrupt the FB factorial structure, and only few features moved among factors. Factor Analysis indicates that during BH (1) only the SC described the emotional output, (2) the sympathetic tone on heart did not change, (3) the dynamics of interbeats intervals showed an increase of long-range correlation that anticipates the HPBH, followed by a drop to a random behavior. In conclusion, data show that the autonomic control on heart rate and SC are differentially modulated during BH, which could be related to a more pronounced effect on emotional control induced by the mental training to BH. PMID:22461774

The Risk of Neurological Dysfunctions after Deep Hypothermic Circulatory Arrest with Retrograde Cerebral Perfusion.

PubMed

Gatti, Giuseppe; Benussi, Bernardo; Currò, Placido; Forti, Gabriella; Rauber, Elisabetta; Minati, Alessandro; Gabrielli, Marco; Tognolli, Umberto; Sinagra, Gianfranco; Pappalardo, Aniello

2017-12-01

Retrograde cerebral perfusion (RCP) is a brain protection technique that is adopted generally for anticipated short periods of deep hypothermic circulatory arrest (DHCA). However, the real impact of this technique on cerebral protection during DHCA remains a controversial issue. For 344 (59.5%) of 578 consecutive patients (mean age, 66.9 ± 10.9 years) who underwent cardiovascular surgery under DHCA at the present authors' institution (1999-2015), RCP was the sole technique of cerebral protection that was adopted in addition to deep hypothermia. Surgery of the thoracic aorta was performed in 95.9% of these RCP patients; in 92 cases there was an aortic arch involvement. Outcomes were reviewed retrospectively. The focus was on postoperative neurological dysfunctions. There were 33 (9.6%) in-hospital deaths. Thirty-one (9%) patients had permanent neurological dysfunctions and 66 (19.1%) transitory neurological dysfunctions alone. Age older than 74 years (odds ratio [OR], 1.88, P = .023), surgery for acute aortic dissection (OR, 2.57; P = .0009), and DHCA time longer than 25 minutes (OR, 2.44; P = .0021) were predictors of neurological dysfunctions. The 10-year nonparametric estimate of freedom from all-cause death was 61.8% (95% confidence interval, 57.8%-65.8%). Permanent postoperative neurological dysfunctions were risk factors for cardiac or cerebrovascular death (hazard ratio, 2.6; P = .039) even after an adjusted survival analysis (P < .04). According to the study findings, RCP, in addition to deep hypothermia, combines with a low risk of neurological dysfunctions provided that DHCA length is 25 minutes or less. Permanent postoperative neurological dysfunctions are predictors of poor late survival. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Fully automated registration of first-pass myocardial perfusion MRI using independent component analysis.

PubMed

Milles, J; van der Geest, R J; Jerosch-Herold, M; Reiber, J H C; Lelieveldt, B P F

2007-01-01

This paper presents a novel method for registration of cardiac perfusion MRI. The presented method successfully corrects for breathing motion without any manual interaction using Independent Component Analysis to extract physiologically relevant features together with their time-intensity behavior. A time-varying reference image mimicking intensity changes in the data of interest is computed based on the results of ICA, and used to compute the displacement caused by breathing for each frame. Qualitative and quantitative validation of the method is carried out using 46 clinical quality, short-axis, perfusion MR datasets comprising 100 images each. Validation experiments showed a reduction of the average LV motion from 1.26+/-0.87 to 0.64+/-0.46 pixels. Time-intensity curves are also improved after registration with an average error reduced from 2.65+/-7.89% to 0.87+/-3.88% between registered data and manual gold standard. We conclude that this fully automatic ICA-based method shows an excellent accuracy, robustness and computation speed, adequate for use in a clinical environment.

Simple motion correction strategy reduces respiratory-induced motion artifacts for k-t accelerated and compressed-sensing cardiovascular magnetic resonance perfusion imaging.

PubMed

Zhou, Ruixi; Huang, Wei; Yang, Yang; Chen, Xiao; Weller, Daniel S; Kramer, Christopher M; Kozerke, Sebastian; Salerno, Michael

2018-02-01

Cardiovascular magnetic resonance (CMR) stress perfusion imaging provides important diagnostic and prognostic information in coronary artery disease (CAD). Current clinical sequences have limited temporal and/or spatial resolution, and incomplete heart coverage. Techniques such as k-t principal component analysis (PCA) or k-t sparcity and low rank structure (SLR), which rely on the high degree of spatiotemporal correlation in first-pass perfusion data, can significantly accelerate image acquisition mitigating these problems. However, in the presence of respiratory motion, these techniques can suffer from significant degradation of image quality. A number of techniques based on non-rigid registration have been developed. However, to first approximation, breathing motion predominantly results in rigid motion of the heart. To this end, a simple robust motion correction strategy is proposed for k-t accelerated and compressed sensing (CS) perfusion imaging. A simple respiratory motion compensation (MC) strategy for k-t accelerated and compressed-sensing CMR perfusion imaging to selectively correct respiratory motion of the heart was implemented based on linear k-space phase shifts derived from rigid motion registration of a region-of-interest (ROI) encompassing the heart. A variable density Poisson disk acquisition strategy was used to minimize coherent aliasing in the presence of respiratory motion, and images were reconstructed using k-t PCA and k-t SLR with or without motion correction. The strategy was evaluated in a CMR-extended cardiac torso digital (XCAT) phantom and in prospectively acquired first-pass perfusion studies in 12 subjects undergoing clinically ordered CMR studies. Phantom studies were assessed using the Structural Similarity Index (SSIM) and Root Mean Square Error (RMSE). In patient studies, image quality was scored in a blinded fashion by two experienced cardiologists. In the phantom experiments, images reconstructed with the MC strategy had higher

Weyl magnons in breathing pyrochlore antiferromagnets

PubMed Central

Li, Fei-Ye; Li, Yao-Dong; Kim, Yong Baek; Balents, Leon; Yu, Yue; Chen, Gang

2016-01-01

Frustrated quantum magnets not only provide exotic ground states and unusual magnetic structures, but also support unconventional excitations in many cases. Using a physically relevant spin model for a breathing pyrochlore lattice, we discuss the presence of topological linear band crossings of magnons in antiferromagnets. These are the analogues of Weyl fermions in electronic systems, which we dub Weyl magnons. The bulk Weyl magnon implies the presence of chiral magnon surface states forming arcs at finite energy. We argue that such antiferromagnets present a unique example, in which Weyl points can be manipulated in situ in the laboratory by applied fields. We discuss their appearance specifically in the breathing pyrochlore lattice, and give some general discussion of conditions to find Weyl magnons, and how they may be probed experimentally. Our work may inspire a re-examination of the magnetic excitations in many magnetically ordered systems. PMID:27650053

Weyl magnons in breathing pyrochlore antiferromagnets

DOE PAGES

Li, Fei-Ye; Li, Yao-Dong; Kim, Yong Baek; ...

2016-09-21

Frustrated quantum magnets not only provide exotic ground states and unusual magnetic structures, but also support unconventional excitations in many cases. Using a physically relevant spin model for a breathing pyrochlore lattice, we discuss the presence of topological linear band crossings of magnons in antiferromagnets. These are the analogues of Weyl fermions in electronic systems, which we dub Weyl magnons. The bulk Weyl magnon implies the presence of chiral magnon surface states forming arcs at finite energy. We argue that such antiferromagnets present a unique example, in which Weyl points can be manipulated in situ in the laboratory by appliedmore » fields. We discuss their appearance specifically in the breathing pyrochlore lattice, and give some general discussion of conditions to find Weyl magnons, and how they may be probed experimentally. Our work may inspire a re-examination of the magnetic excitations in many magnetically ordered systems.« less

Respiratory mechanics and breathing pattern in the neonatal foal.

PubMed

Koterba, A M; Kosch, P C

1987-01-01

Breathing pattern, respiratory muscle activation pattern, lung volumes and volume-pressure characteristics of the respiratory system of normal, term, neonatal foals on Days 2 and 7 of age were determined to test the hypothesis that the foal actively maintains end-expiratory lung volume (EEV) greater than the relaxation volume of the respiratory system (Vrx) because of a highly compliant chest wall. Breathing pattern was measured in the awake, unsedated foal during quiet breathing in lateral and standing positions. The typical neonatal foal breathing pattern was characterized by a monophasic inspiratory and expiratory flow pattern. Both inspiration and expiration were active, with onset of Edi activity preceding onset of inspiratory flow, and phasic abdominal muscle activity detectable throughout most of expiration. No evidence was found to support the hypothesis that the normal, term neonatal foal actively maintains EEV greater than Vrx. In the neonatal foal, normalized lung volume and lung compliance values were similar to those reported for neonates of other species, while normalized chest wall compliance was considerably lower. We conclude that the chest wall of the term neonatal foal is sufficiently rigid to prevent a low Vrx. This characteristic probably prevents the foal from having to use a breathing strategy which maintains an EEV greater than Vrx.

Reduced lung dose during radiotherapy for thoracic esophageal carcinoma: VMAT combined with active breathing control for moderate DIBH.

PubMed

Gong, Guanzhong; Wang, Ruozheng; Guo, Yujie; Zhai, Deyin; Liu, Tonghai; Lu, Jie; Chen, Jinhu; Liu, Chengxin; Yin, Yong

2013-12-20

Lung radiation injury is a critical complication of radiotherapy (RT) for thoracic esophageal carcinoma (EC). Therefore, the goal of this study was to investigate the feasibility and dosimetric effects of reducing the lung tissue irradiation dose during RT for thoracic EC by applying volumetric modulated arc radiotherapy (VMAT) combined with active breathing control (ABC) for moderate deep inspiration breath-hold (mDIBH). Fifteen patients with thoracic EC were randomly selected to undergo two series of computed tomography (CT) simulation scans with ABC used to achieve mDIBH (representing 80% of peak DIBH value) versus free breathing (FB). Gross tumor volumes were contoured on different CT images, and planning target volumes (PTVs) were obtained using different margins. For PTV-FB, intensity-modulated radiotherapy (IMRT) was designed with seven fields, and VMAT included two whole arcs. For PTV-DIBH, VMAT with three 135° arcs was applied, and the corresponding plans were named: IMRT-FB, VMAT-FB, and VMAT-DIBH, respectively. Dosimetric differences between the different plans were compared. The heart volumes decreased by 19.85%, while total lung volume increased by 52.54% in mDIBH, compared to FB (p < 0.05). The mean conformality index values and homogeneity index values for VMAT-DIBH (0.86, 1.07) were slightly worse than those for IMRT-FB (0.90, 1.05) and VMAT-FB (0.90, 1.06) (p > 0.05). Furthermore, compared to IMRT-FB and VMAT-FB, VMAT-DIBH reduced the mean total lung dose by 18.64% and 17.84%, respectively (p < 0.05); moreover, the V5, V10, V20, and V30 values for IMRT-FB and VMAT-FB were reduced by 10.84% and 10.65% (p > 0.05), 12.5% and 20% (p < 0.05), 30.77% and 33.33% (p < 0.05), and 50.33% and 49.15% (p < 0.05), respectively. However, the heart dose-volume indices were similar between VMAT-DIBH and VMAT-FB which were lower than IMRT-FB without being statistically significant (p > 0.05). The monitor units and treatment time of VMAT-DIBH were also the lowest (p

Iris Transponder-Communications and Navigation for Deep Space

NASA Technical Reports Server (NTRS)

Duncan, Courtney B.; Smith, Amy E.; Aguirre, Fernando H.

2014-01-01

The Jet Propulsion Laboratory has developed the Iris CubeSat compatible deep space transponder for INSPIRE, the first CubeSat to deep space. Iris is 0.4 U, 0.4 kg, consumes 12.8 W, and interoperates with NASA's Deep Space Network (DSN) on X-Band frequencies (7.2 GHz uplink, 8.4 GHz downlink) for command, telemetry, and navigation. This talk discusses the Iris for INSPIRE, it's features and requirements; future developments and improvements underway; deep space and proximity operations applications for Iris; high rate earth orbit variants; and ground requirements, such as are implemented in the DSN, for deep space operations.

7. VIEW FROM NEAR INSPIRATION POINT, MOUNT RAINIER IN BACKGROUND, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. VIEW FROM NEAR INSPIRATION POINT, MOUNT RAINIER IN BACKGROUND, HAER HISTORIAN RICHARD QUIN HOLDING SCALE STICK - Stevens Canyon Highway, Between Paradise, WA, & State Highway 123, Ashford, Pierce County, WA

Exercise at depth alters bradycardia and incidence of cardiac anomalies in deep-diving marine mammals.

PubMed

Williams, Terrie M; Fuiman, Lee A; Kendall, Traci; Berry, Patrick; Richter, Beau; Noren, Shawn R; Thometz, Nicole; Shattock, Michael J; Farrell, Edward; Stamper, Andy M; Davis, Randall W

2015-01-16

Unlike their terrestrial ancestors, marine mammals routinely confront extreme physiological and physical challenges while breath-holding and pursuing prey at depth. To determine how cetaceans and pinnipeds accomplish deep-sea chases, we deployed animal-borne instruments that recorded high-resolution electrocardiograms, behaviour and flipper accelerations of bottlenose dolphins (Tursiops truncatus) and Weddell seals (Leptonychotes weddellii) diving from the surface to >200 m. Here we report that both exercise and depth alter the bradycardia associated with the dive response, with the greatest impacts at depths inducing lung collapse. Unexpectedly, cardiac arrhythmias occurred in >73% of deep, aerobic dives, which we attribute to the interplay between sympathetic and parasympathetic drivers for exercise and diving, respectively. Such marked cardiac variability alters the common view of a stereotypic 'dive reflex' in diving mammals. It also suggests the persistence of ancestral terrestrial traits in cardiac function that may help explain the unique sensitivity of some deep-diving marine mammals to anthropogenic disturbances.

Active Breathing Control for Hodgkin's Disease in Childhood and Adolescence: Feasibility, Advantages, and Limits

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

Claude, Line; Malet, Claude Phys.; Pommier, Pascal

2007-04-01

Purpose: The challenge in early Hodgkin's disease (HD) in children is to maintain good survival rates while sparing organs at risk. This study assesses the feasibility of active breathing control (ABC) in children, and compares normal tissue irradiation with and without ABC. Methods and Materials: Between May 2003 and June 2004, seven children with HD with mediastinal involvement, median age 15, were treated by chemotherapy and involved-field radiation therapy. A free-breathing computed tomography simulation scan and one additional scan during deep inspiration using ABC were performed. A comparison between planning treatment with clinical target volume including supraclavicular regions, mediastinum, andmore » hila was performed, both in free breathing and using ABC. Results: For a prescription of 36 Gy, pulmonary dose-volume histograms revealed a mean reduction in lung volume irradiated at more than 20 Gy (V20) and 30 Gy (V30) of 25% and 26%, respectively, using ABC (p = 0.016). The mean volume of heart irradiated at 30 Gy or more decreased from 15% to 12% (nonsignificant). The mean dose delivered to breasts in girls was small in both situations (less than 2 Gy) and stable with or without ABC. Considering axillary irradiation, the mean dose delivered to breasts remained low (<9 Gy), without significant difference using ABC or not. The mean radiation dose delivered to thyroid was stable using ABC or not. Conclusions: Using ABC is feasible in childhood. The use of ABC decreases normal lung tissue irradiation. Concerning heart irradiation, a minimal gain is also shown. No significant change has been demonstrated concerning breast and thyroid irradiation.« less

Learning to breathe? Feedforward regulation of the inspiratory motor drive.

PubMed

Zaman, Jonas; Van den Bergh, Omer; Fannes, Stien; Van Diest, Ilse

2014-09-15

Claims have been made that breathing is in part controlled by feedforward regulation. In a classical conditioning paradigm, we investigated anticipatory increases in the inspiratory motor drive as measured by inspiratory occlusion pressure (P100). In an acquisition phase, an experimental group (N=13) received a low-intensity resistive load (5 cmH2O/l/s) for three consecutive inspirations as Conditioned Stimulus (CS), preceding a load of a stronger intensity (20 cmH2O/l/s) for three subsequent inspirations as unconditioned stimulus (US). The control group (N=11) received the low-intensity load for six consecutive inspirations. In a post-acquisition phase both groups received the low-intensity load for six consecutive inspirations. Responses to the CS-load only differed between groups during the first acquisition trials and a strong increase in P100 during the US-loads was observed, which habituated across the experiment. Our results suggest that the disruption caused by adding low to moderate resistive loads to three consecutive inspirations results in a short-lasting anticipatory increase in inspiratory motor drive. Copyright © 2014 Elsevier B.V. All rights reserved.

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

The effects of voluntary control of respiration on the excitability of the primary motor hand area, evaluated by end-tidal CO2 monitoring.

PubMed

Ozaki, Isamu; Kurata, Kiyoshi

2015-11-01

To investigate the effects of voluntary deep breathing on the excitability of the hand area in the primary motor cortex (M1). We applied near-threshold transcranial magnetic stimulation (TMS) over M1 during the early phase of inspiration or expiration in both normal automatic and voluntary deep, but not "forced", breathing in eight healthy participants at rest. We monitored exhaled CO2 levels continuously, and recorded motor-evoked potentials (MEPs) simultaneously from the abductor pollicis brevis, first dorsal interosseous, abductor digiti minimi, flexor digitorum superficialis, and extensor incidis muscles. We observed that, during voluntary deep breathing, MEP amplitude increased by up to 50% for all recorded muscles and the latency of MEPs decreased by approximately 1ms, compared with normal automatic breathing. We found no difference in the amplitude or latency of MEPs between inspiratory and expiratory phases in either normal automatic or voluntary deep breathing. Voluntary deep breathing at rest facilitates MEPs following TMS over the hand area of M1, and MEP enhancement occurs throughout the full respiratory cycle. The M1 hand region is continuously driven by top-down neural signals over the entire respiratory cycle of voluntary deep breathing. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

A Novel Deep Inspiration Maneuver for Difficult Transseptal Puncture.

PubMed

Aksu, Tolga; Guler, Tumer Erdem; Yalin, Kivanc; Golcuk, Sukriye Ebru; Ozcan, Kazim Serhan; Guler, Niyazi

2017-02-01

Transseptal puncture (TSP) may not be possible in cases of an elastic, aneurysmal, or thickened interatrial septum (IAS). During deep inspiration (DI), the chest wall expands and the diaphragm descends. This makes intrapleural pressure to become more negative, which leads to movement of the IAS to the right side. The aim of this study was to verify prospectively the feasibility, safety, and outcome of DI associated with conventional TSP technique in patients with challenging IAS anatomy. From September 2012 to May 2016, 224 patients underwent TSP due to different indications. Patients were divided into 2 groups: 213 patients in whom the left atrium was successfully accessed in 3 attempts were grouped as conventional TSP group and 11 patients in whom left atrium access was failed after 3 conventional attempts were grouped as DI-TSP group. Conventional TSP was successful in 89.6% of patients with the first attempt. Second and third attempts were required in 4.1% and 1.4%, respectively. Septal puncture was achieved at the first attempt in 10 patients within a median of 1 second of DI maneuver (interquartile range, 1 to 3) and without any complications. Challenging IAS anatomy consisting of IAS aneurysm, a thick IAS, and an excessively mobile IAS were more frequent in the DI-TSP group (45% to 8%, 27% to 3%, and 21% to 5%, respectively, p <0.001). In conclusion, TSP by using the DI maneuver may be a reliable and safe method after failed conventional attempts. If there is any doubt about the correct location of the needle, additional imaging modalities have to be used. Copyright © 2016 Elsevier Inc. All rights reserved.

Cardiorespiratory and autonomic interactions during snoring related resistive breathing.

PubMed

Mateika, J H; Mitru, G

2001-03-15

We hypothesized that blood pressure (BP) is less during snoring as compared to periods of non-snoring in non-apneic individuals. Furthermore, we hypothesized that this reduction may be accompanied by a simultaneous decrease in sympathetic (SNSA) and parasympathetic (PNSA) nervous system activity and an increase in heart rate (HR). N/A. N/A. N/A. The variables mentioned above in addition to breathing frequency were measured in 9 subjects during NREM sleep. In addition, the lowest systolic (SBP) and diastolic blood pressure (DBP) during inspiration and the highest SBP and DBP during expiration was determined breath-by-breath from segments selected from each NREM cycle. Heart rate variability was used as a marker of autonomic nervous system activity. Our results showed that BP during snoring decreased compared to non-snoring and the breath-by-breath BP analysis suggested that this difference may have been mediated by changes in intrathoracic pressure. In conjunction with the decrease in BP, SNSA decreased and HR increased however PNSA remained constant. Thus, a decrease in PNSA was likely not the primary mechanism responsible for the HR response. We conclude that BP responses and SNSA during snoring are similar to that reported previously in non-snoring individuals. However, the causal mechanisms maybe different and manifested in other measures such as HR. Thus, nocturnal cardiovascular and autonomic function maybe uniquely different in non-apneic snoring individuals.

Examining Ritual in a Reggio-Inspired Preschool

ERIC Educational Resources Information Center

Hayes, Shirley

2015-01-01

Working and researching in a Reggio-inspired preschool for one year allowed me to witness repeated rituals of schooling, especially the walk-around-the-candle birthday ceremony. In this paper, I focus on the importance of ritual to human endeavors and share the educational, transformational, and caring quality that these rituals hold for children…

Coaxial Tubing Systems Increase Artificial Airway Resistance and Work of Breathing.

PubMed

Wenzel, Christin; Schumann, Stefan; Spaeth, Johannes

2017-09-01

Tubing systems are an essential component of the ventilation circuit, connecting the ventilator to the patient's airways. Coaxial tubing systems incorporate the inspiratory tube within the lumen of the expiratory one. We hypothesized that by design, these tubing systems increase resistance to air flow compared with conventional ones. We investigated the flow-dependent pressure gradient across coaxial, conventional disposable, and conventional reusable tubing systems from 3 different manufacturers. Additionally, the additional work of breathing and perception of resistance during breathing through the different devices were determined in 18 healthy volunteers. The pressure gradient across coaxial tubing systems was up to 6 times higher compared with conventional ones (1.90 ± 0.03 cm H 2 O vs 0.34 ± 0.01 cm H 2 O, P < .001) and was higher during expiration compared with inspiration ( P < .001). Additional work of breathing and perceived breathing resistance were highest in coaxial tubing systems, accordingly. Our findings suggest that the use of coaxial tubing systems should be carefully considered with respect to their increased resistance. Copyright © 2017 by Daedalus Enterprises.

Influence of Deep Breathing on Heart Rate Variability in Parkinson's Disease: Co-relation with Severity of Disease and Non-Motor Symptom Scale Score.

PubMed

Bidikar, Mukta Pritam; Jagtap, Gayatri J; Chakor, Rahul T

2014-07-01

Dysautonomia and non-motor symptoms (NMS) in Parkinson's disease (PD) are frequent, disabling and reduce quality of life of patient. There is a paucity of studies on autonomic dysfunction in PD in Indian population. The study aimed to evaluate autonomic dysfunction in PD patients and co-relate the findings with severity of PD and Non-Motor Symptoms Scale (NMSS) score. We evaluated autonomic function in 30 diagnosed patients of PD (age 55-70 years) and 30 healthy age-matched controls by 3 min deep breathing test (DBT). NMSS was used to identify non-motor symptoms and Hoehn and Yahr (HY) Scale to grade severity of PD. The DBT findings were co-related with severity of PD (HY staging) and NMSS score. DBT was found to be abnormal in 40% while it was on borderline in 33.3% of PD patients. There was a statistically significant difference (p<0.01) between patients and control group for the DBT. NMS were reported across all the stages of PD but with variable frequency and severity for individual symptom. A negative co-relation was found between results of deep breathing test and clinical severity of disease and NMSS score. Abnormalities of autonomic function and NMS were integral and present across all the stages of PD patients. Early recognition and treatment of these may decrease morbidity and improve quality of life of PD patients.

Abdominal 4D flow MR imaging in a breath hold: combination of spiral sampling and dynamic compressed sensing for highly accelerated acquisition.

PubMed

Dyvorne, Hadrien; Knight-Greenfield, Ashley; Jajamovich, Guido; Besa, Cecilia; Cui, Yong; Stalder, Aurélien; Markl, Michael; Taouli, Bachir

2015-04-01

To develop a highly accelerated phase-contrast cardiac-gated volume flow measurement (four-dimensional [4D] flow) magnetic resonance (MR) imaging technique based on spiral sampling and dynamic compressed sensing and to compare this technique with established phase-contrast imaging techniques for the quantification of blood flow in abdominal vessels. This single-center prospective study was compliant with HIPAA and approved by the institutional review board. Ten subjects (nine men, one woman; mean age, 51 years; age range, 30-70 years) were enrolled. Seven patients had liver disease. Written informed consent was obtained from all participants. Two 4D flow acquisitions were performed in each subject, one with use of Cartesian sampling with respiratory tracking and the other with use of spiral sampling and a breath hold. Cartesian two-dimensional (2D) cine phase-contrast images were also acquired in the portal vein. Two observers independently assessed vessel conspicuity on phase-contrast three-dimensional angiograms. Quantitative flow parameters were measured by two independent observers in major abdominal vessels. Intertechnique concordance was quantified by using Bland-Altman and logistic regression analyses. There was moderate to substantial agreement in vessel conspicuity between 4D flow acquisitions in arteries and veins (κ = 0.71 and 0.61, respectively, for observer 1; κ = 0.71 and 0.44 for observer 2), whereas more artifacts were observed with spiral 4D flow (κ = 0.30 and 0.20). Quantitative measurements in abdominal vessels showed good equivalence between spiral and Cartesian 4D flow techniques (lower bound of the 95% confidence interval: 63%, 77%, 60%, and 64% for flow, area, average velocity, and peak velocity, respectively). For portal venous flow, spiral 4D flow was in better agreement with 2D cine phase-contrast flow (95% limits of agreement: -8.8 and 9.3 mL/sec, respectively) than was Cartesian 4D flow (95% limits of agreement: -10.6 and 14.6 m

WE-AB-202-07: Ventilation CT: Voxel-Level Comparison with Hyperpolarized Helium-3 & Xenon-129 MRI

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

Tahir, B; Marshall, H; Hughes, P

Purpose: To compare the spatial correlation of ventilation surrogates computed from inspiratory and expiratory breath-hold CT with hyperpolarized Helium-3 & Xenon-129 MRI in a cohort of lung cancer patients. Methods: 5 patients underwent expiration & inspiration breath-hold CT. Xenon-129 & {sup 1}H MRI were also acquired at the same inflation state as inspiratory CT. This was followed immediately by acquisition of Helium-3 & {sup 1}H MRI in the same breath and at the same inflation state as inspiratory CT. Expiration CT was deformably registered to inspiration CT for calculation of ventilation CT from voxel-wise differences in Hounsfield units. Inspiration CTmore » and the Xenon-129’s corresponding anatomical {sup 1}H MRI were registered to Helium-3 MRI via the same-breath anatomical {sup 1}H MRI. This enabled direct comparison of CT ventilation with Helium-3 MRI & Xenon-129 MRI for the median values in corresponding regions of interest, ranging from finer to coarser in-plane dimensions of 10 by 10, 20 by 20, 30 by 30 and 40 by 40, located within the lungs as defined by the same-breath {sup 1}H MRI lung mask. Spearman coefficients were used to assess voxel-level correlation. Results: The median Spearman’s coefficients of ventilation CT with Helium-3 & Xenon-129 MRI for ROIs of 10 by 10, 20 by 20, 30 by 30 and 40 by 40 were 0.52, 0.56, 0.60 and 0.68 and 0.40, 0.42, 0.52 and 0.70, respectively. Conclusion: This work demonstrates a method of acquiring CT & hyperpolarized gas MRI (Helium-3 & Xenon-129 MRI) in similar breath-holds to enable direct spatial comparison of ventilation maps. Initial results show moderate correlation between ventilation CT & hyperpolarized gas MRI, improving for coarser regions which could be attributable to the inherent noise in CT intensity, non-ventilatory effects and registration errors at the voxel-level. Thus, it may be more beneficial to quantify ventilation at a more regional level.« less

First in vivo magnetic particle imaging of lung perfusion in rats

NASA Astrophysics Data System (ADS)

Zhou, Xinyi Y.; Jeffris, Kenneth E.; Yu, Elaine Y.; Zheng, Bo; Goodwill, Patrick W.; Nahid, Payam; Conolly, Steven M.

2017-05-01

Pulmonary embolism (PE), along with the closely related condition of deep vein thrombosis, affect an estimated 600 000 patients in the US per year. Untreated, PE carries a mortality rate of 30%. Because many patients experience mild or non-specific symptoms, imaging studies are necessary for definitive diagnosis of PE. Iodinated CT pulmonary angiography is recommended for most patients, while nuclear medicine-based ventilation/perfusion (V/Q) scans are reserved for patients in whom the use of iodine is contraindicated. Magnetic particle imaging (MPI) is an emerging tracer imaging modality with high image contrast (no tissue background signal) and sensitivity to superparamagnetic iron oxide (SPIO) tracer. Importantly, unlike CT or nuclear medicine, MPI uses no ionizing radiation. Further, MPI is not derived from magnetic resonance imaging (MRI); MPI directly images SPIO tracers via their strong electronic magnetization, enabling deep imaging of anatomy including within the lungs, which is very challenging with MRI. Here, the first high-contrast in vivo MPI lung perfusion images of rats are shown using a novel lung perfusion agent, MAA-SPIOs.

Dyssynchronous breathing during arm but not leg exercise in patients with chronic airflow obstruction.

PubMed

Celli, B R; Rassulo, J; Make, B J

1986-06-05

Some patients with chronic airflow obstruction experience dyspnea with mild arm exercise but not with more-intense leg exercise. To investigate why these patients have limited endurance during arm exertion, we studied ventilatory responses to exercise with unsupported arms in 12 patients with chronic airflow obstruction (mean [+/- SD] forced expiratory volume in one second, 0.68 +/- 0.28 liters). Unloaded leg cycling was also studied for comparison. In the five patients who had the most severe airflow obstruction, arm exercise was limited by dyspnea after 3.3 +/- 0.7 minutes, and dyssynchronous thoracoabdominal breathing developed. In the other seven patients, arm exercise was limited by the sensation of muscle fatigue after 6.1 +/- 2.0 minutes (P less than 0.05), and dyssynchronous breathing did not occur. None of the 12 patients had dyssynchronous breathing during unloaded leg cycling. Maximal transdiaphragmatic pressure, a measure of diaphragmatic fatigue, declined similarly after arm and leg exercise in both groups. During unsupported arm work, the accessory muscles of inspiration help position the torso and arms. We hypothesize that the extra demand placed on these muscles during arm exertion leads to early fatigue, an increased load on the diaphragm, and dyssynchronous thoracoabdominal inspirations. This sequence may contribute to dyspnea and limited endurance during upper-extremity exercise.

Liver diffusion-weighted MR imaging: reproducibility comparison of ADC measurements obtained with multiple breath-hold, free-breathing, respiratory-triggered, and navigator-triggered techniques.

PubMed

Chen, Xin; Qin, Lei; Pan, Dan; Huang, Yanqi; Yan, Lifen; Wang, Guangyi; Liu, Yubao; Liang, Changhong; Liu, Zaiyi

2014-04-01

To prospectively compare the reproducibility of normal liver apparent diffusion coefficient (ADC) measurements by using different respiratory motion compensation techniques with multiple breath-hold (MBH), free-breathing (FB), respiratory-triggered (RT), and navigator-triggered (NT) diffusion-weighted (DW) imaging and to compare the ADCs at different liver anatomic locations. The study protocol was approved by the institutional review board, and written informed consent was obtained from each participant. Thirty-nine volunteers underwent liver DW imaging twice. Imaging was performed with a 1.5-T MR imager with MBH, FB, RT, and NT techniques (b = 0, 100, and 500 sec/mm(2)). Three representative sections--superior, central, and inferior--were selected on left and right liver lobes, respectively. On each selected section, three regions of interest were drawn, and ADCs were measured. Analysis of variance was used to assess ADCs among the four techniques and various anatomic locations. Reproducibility of ADCs was assessed with the Bland-Altman method. ADCs obtained with MBH (range: right lobe, [1.641-1.662] × 10(-3)mm(2)/sec; left lobe, [2.034-2.054] ×10(-3)mm(2)/sec) were higher than those obtained with FB (right, [1.349-1.391] ×10(-3)mm(2)/sec; left, [1.630-1.700] ×10(-3)mm(2)/sec), RT (right, [1.439-1.455] ×10(-3)mm(2)/sec; left, [1.720-1.755] ×10(-3)mm(2)/sec), or NT (right, [1.387-1.400] ×10(-3)mm(2)/sec; left, [1.661-1.736] ×10(-3)mm(2)/sec) techniques (P < .001); however, no significant difference was observed between ADCs obtained with FB, RT, and NT techniques (P = .130 to P >.99). ADCs showed a trend to decrease moving from left to right. Reproducibility in the left liver lobe was inferior to that in the right, and the central middle segment in the right lobe had the most reproducible ADC. Statistical differences in ADCs were observed in the left-right direction in the right lobe (P < .001), but they were not observed in the superior-inferior direction

Arterial stress hormones during scuba diving with different breathing gases.

PubMed

Weist, Frank; Strobel, Günther; Hölzl, Mathias; Böning, Dieter

2012-07-01

The purpose of the study was to determine whether the conditions during scuba diving without exercise (e.g., submersion, restricted breathing) stimulate the activities of the sympathoadrenergic system and the hypothalamic-pituitary-adrenal axis. This might facilitate panic reactions in dangerous situations. Fifteen experienced rescue divers participated in three experiments with two submersions each in a diving tower where ambient pressure could be varied. During submersion (duration = 15 min), they were breathing either pure oxygen (ambient pressure = 1.1 bar) or air (1.1 and 5.3 bar) or Heliox21 (21% O(2) and 79% He, 1.1 and 5.3 bar). The subjects stayed upright immediately below the water surface holding one hand with a cannulated radial artery out in the air. Noradrenaline, adrenaline, and dopamine concentrations in arterial blood and heart rate (HR) variability as indicators of sympathoadrenergic activity and cortisol and adrenocorticotropic hormone concentrations as strain indicators were measured. [Noradrenaline] and [adrenaline] (initial values (mean ± SE) = 1616 ± 93 and 426 ± 38 pmol·L(-1)) decreased significantly by up to 30% and 50%, respectively, after 11 min of submersion, independent of pressure and inspired gas. HR variability showed roughly corresponding changes and also indications for parasympathetic stimulation, but artifacts by interference among HR monitors reduced the number of usable measurements. The other hormone concentrations did not change significantly. There was no increase of stress hormone concentrations in experienced subjects. The reduction of [noradrenaline] and [adrenaline] during scuba diving seems to be a reaction to orthostatic relief caused by external hydrostatic pressure on peripheral vasculature. The activity of the vegetative nervous system might be estimated from HR variability if interference among pulse watches can be avoided.

Response to deep hypoglycemia does not involve glucoreceptors in carotid perfused tissue

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

Cane, P.; Haun, C.K.; Evered, J.

1988-11-01

In the present study the authors examined whether the magnified hormonal counter-regulatory response seen during deep hypoglycemia (40 mg/dl) could be attenuated by supplying the forebrain with glucose furnished through carotid infusion. Two protocols were performed in conscious dogs. In the first protocol they infused glucose bilaterally into the carotid circulation to produce a forebrain glycemia of 55 {plus minus} 1 mg/dl whereas systemic glycemia declined to 39 {plus minus} 2 mg/dl. In the second protocol as a control they infused glucose into the systemic circulation at a rate matched to protocol 1 so that both systemic and jugular plasmamore » glucose concentrations were equivalent to the systemic glucose concentrations in protocol 1. In spite of a substantial difference in forebrain glycemia there were no differences in the counter-regulatory responses of catecholamines or glucagon. In addition, through the use of radiolabeled microspheres, they defined the precise regions of the forebrain irrigated during bilateral intracarotid glucose infusions. The concentration of microspheres was high in the forebrain but very low in the hindbrain. The results indicate that glucoreceptor cells in tissues perfused by carotid arteries may play a tautological role in the sympathetic response to hypoglycemia and imply that glucose-sensitive receptors must also be located elsewhere in the central nervous system or in the periphery.« less

Poster – 41: External marker block placement on the breast or chest wall for left-sided deep inspiration breath-hold radiotherapy

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

Conroy, Leigh; Guebert, Alexandra; Smith, Wendy

Purpose: We investigate DIBH breast radiotherapy using the Real-time Position Management (RPM) system with the marker-block placed on the target breast or chest wall. Methods: We measured surface dose for three different RPM marker-blocks using EBT3 Gafchromic film at 0° and 30° incidence. A registration study was performed to determine the breast surface position that best correlates with overall internal chest wall position. Surface and chest wall contours from MV images of the medial tangent field were extracted for 15 patients. Surface contours were divided into three potential marker-block positions on the breast: Superior, Middle, and Inferior. Translational registration wasmore » used to align the partial contours to the first-fraction contour. Each resultant transformation matrix was applied to the chest wall contour, and the minimum distance between the reference chest wall contour and the transformed chest wall contour was evaluated for each pixel. Results: The measured surface dose for the 2-dot, 6-dot, and 4-dot marker-blocks at 0° incidence were 74%, 71%, and 77% of dose to dmax respectively. At 30° beam incidence this increased to 76%, 72%, and 81%. The best external surface position was patient and fraction dependent, with no consistent best choice. Conclusions: The increase in surface dose directly under the RPM block is approximately equivalent to 3 mm of bolus. No marker-block position on the breast surface was found to be more representative of overall chest wall motion; therefore block positional stability and reproducibility can be used to determine optimal placement on the breast or chest wall.« less

Slow Breathing and Hypoxic Challenge: Cardiorespiratory Consequences and Their Central Neural Substrates

PubMed Central

Critchley, Hugo D.; Nicotra, Alessia; Chiesa, Patrizia A.; Nagai, Yoko; Gray, Marcus A.; Minati, Ludovico; Bernardi, Luciano

2015-01-01

Controlled slow breathing (at 6/min, a rate frequently adopted during yoga practice) can benefit cardiovascular function, including responses to hypoxia. We tested the neural substrates of cardiorespiratory control in humans during volitional controlled breathing and hypoxic challenge using functional magnetic resonance imaging (fMRI). Twenty healthy volunteers were scanned during paced (slow and normal rate) breathing and during spontaneous breathing of normoxic and hypoxic (13% inspired O2) air. Cardiovascular and respiratory measures were acquired concurrently, including beat-to-beat blood pressure from a subset of participants (N = 7). Slow breathing was associated with increased tidal ventilatory volume. Induced hypoxia raised heart rate and suppressed heart rate variability. Within the brain, slow breathing activated dorsal pons, periaqueductal grey matter, cerebellum, hypothalamus, thalamus and lateral and anterior insular cortices. Blocks of hypoxia activated mid pons, bilateral amygdalae, anterior insular and occipitotemporal cortices. Interaction between slow breathing and hypoxia was expressed in ventral striatal and frontal polar activity. Across conditions, within brainstem, dorsal medullary and pontine activity correlated with tidal volume and inversely with heart rate. Activity in rostroventral medulla correlated with beat-to-beat blood pressure and heart rate variability. Widespread insula and striatal activity tracked decreases in heart rate, while subregions of insular cortex correlated with momentary increases in tidal volume. Our findings define slow breathing effects on central and cardiovascular responses to hypoxic challenge. They highlight the recruitment of discrete brainstem nuclei to cardiorespiratory control, and the engagement of corticostriatal circuitry in support of physiological responses that accompany breathing regulation during hypoxic challenge. PMID:25973923

Single-energy computed tomography-based pulmonary perfusion imaging: Proof-of-principle in a canine model

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

Yamamoto, Tokihiro, E-mail: toyamamoto@ucdavis.edu

Purpose: Radiotherapy (RT) that selectively avoids irradiating highly functional lung regions may reduce pulmonary toxicity, which is substantial in lung cancer RT. Single-energy computed tomography (CT) pulmonary perfusion imaging has several advantages (e.g., higher resolution) over other modalities and has great potential for widespread clinical implementation, particularly in RT. The purpose of this study was to establish proof-of-principle for single-energy CT perfusion imaging. Methods: Single-energy CT perfusion imaging is based on the following: (1) acquisition of end-inspiratory breath-hold CT scans before and after intravenous injection of iodinated contrast agents, (2) deformable image registration (DIR) for spatial mapping of those twomore » CT image data sets, and (3) subtraction of the precontrast image data set from the postcontrast image data set, yielding a map of regional Hounsfield unit (HU) enhancement, a surrogate for regional perfusion. In a protocol approved by the institutional animal care and use committee, the authors acquired CT scans in the prone position for a total of 14 anesthetized canines (seven canines with normal lungs and seven canines with diseased lungs). The elastix algorithm was used for DIR. The accuracy of DIR was evaluated based on the target registration error (TRE) of 50 anatomic pulmonary landmarks per subject for 10 randomly selected subjects as well as on singularities (i.e., regions where the displacement vector field is not bijective). Prior to perfusion computation, HUs of the precontrast end-inspiratory image were corrected for variation in the lung inflation level between the precontrast and postcontrast end-inspiratory CT scans, using a model built from two additional precontrast CT scans at end-expiration and midinspiration. The authors also assessed spatial heterogeneity and gravitationally directed gradients of regional perfusion for normal lung subjects and diseased lung subjects using a two-sample two

In Search of the Optimal Heart Perfusion Ultrasound Imaging Platform.

PubMed

Grishenkov, Dmitry; Gonon, Adrian; Janerot-Sjoberg, Birgitta

2015-09-01

Quantification of myocardial perfusion by contrast echocardiography remains a challenge. Existing imaging phantoms used to evaluate the performance of ultrasound scanners do not comply with perfusion basics in the myocardium, where perfusion and motion are inherently coupled. To contribute toward an improvement, we developed a contrast echocardiographic perfusion imaging platform based on an isolated rat heart coupled to an ultrasound scanner. Perfusion was assessed by using 3 different types of contrast agents: dextran-based Promiten (Meda AB, Solna, Sweden), phospholipid-shelled SonoVue (Bracco Diagnostics, Inc, Princeton, NJ), and polymer-shelled MB-pH5-RT, developed in-house. The myocardial video intensity was monitored over time from contrast agent administration to peak, and 2 characteristic constants were calculated by using an exponential fit: A, representing capillary volume; and β, representing inflow velocity. Acquired experimental evidence demonstrates that the application of all 3 contrast agents allows sonographic estimation of myocardial perfusion in the isolated rat heart. Video intensity maps show that an increase in contrast concentration increases the late-plateau values, A, mimicking increased capillary volume. Estimated values of the flow, proportional to A × β, increase when the pressure of the perfusate column increases from 80 to 110 cm of water. This finding is in agreement with the true values of the coronary flow increase measured by a flowmeter attached to the aortic cannula. The contrast echocardiographic perfusion imaging platform described holds promise for standardized evaluation and optimization of contrast perfusion ultrasound imaging in which real-time inflow curves at low acoustic power semiquantitatively reflect coronary flow. © 2015 by the American Institute of Ultrasound in Medicine.

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

Assessment of Tissue Perfusion Following Conventional Liposuction of Perforator-Based Abdominal Flaps

PubMed Central

Saçak, Bülent; Yalçın, Doğuş; Pilancı, Özgür; Tuncer, Fatma Betül; Çelebiler, Özhan

2017-01-01

Background The effect of liposuction on the perforators of the lower abdominal wall has been investigated in several studies. There are controversial results in the literature that have primarily demonstrated the number and patency of the perforators. The aim of this study was to determine the effect of liposuction on the perfusion of perforator-based abdominal flaps using a combined laser–Doppler spectrophotometer (O2C, Oxygen to See, LEA Medizintechnik). Methods Nine female patients undergoing classical abdominoplasty were included in the study. Perforators and the perfusion zones of the deep inferior epigastric artery flap were marked on the patient's abdominal wall. Flap perfusion was quantitatively assessed by measuring blood flow, velocity, capillary oxygen saturation, and relative amount of hemoglobin for each zone preoperatively, after tumescent solution infiltration, following elevation of the flap on a single perforator, and after deep and superficial liposuction, respectively. Results The measurements taken after elevation of the flap were not significantly different than measurements taken after the liposuction procedures. Conclusions The liposuction procedure does not significantly alter the perfusion of perforator-based abdominal flaps in the early period. The abdominal tissue discarded in a classic abdominoplasty operation can be raised as a perforator flap and has been demonstrated to be a unique model for clinical research. PMID:28352599

Does the addition of deep breathing exercises to physiotherapy-directed early mobilisation alter patient outcomes following high-risk open upper abdominal surgery? Cluster randomised controlled trial.

PubMed

Silva, Y R; Li, S K; Rickard, M J F X

2013-09-01

To investigate whether the inclusion of deep breathing exercises in physiotherapy-directed early mobilisation confers any additional benefit in reducing postoperative pulmonary complications (PPCs) when patients are treated once daily after elective open upper abdominal surgery. This study also compared postoperative outcomes following early and delayed mobilisation. Cluster randomised controlled trial. Single-centre study in a teaching hospital. Eighty-six high-risk patients undergoing elective open upper abdominal surgery. Three groups: early mobilisation (Group A), early mobilisation plus breathing exercises (Group B), and delayed mobilisation (mobilised from third postoperative day) plus breathing exercises (Group C). PPCs and postoperative outcomes [number of days until discharge from physiotherapy, physiotherapy input and length of stay (LOS)]. There was no significant difference in PPCs between Groups A and B. The LOS for Group A {mean 10.7 [standard deviation (SD) 5.0] days} was significantly shorter than the LOS for Groups B [mean 16.7 (SD 9.7) days] and C [mean 15.2 (SD 9.8) days; P=0.036]. The greatest difference was between Groups A and B (mean difference -5.93, 95% confidence interval -10.22 to -1.65; P=0.008). Group C had fewer smokers (26%) and patients with chronic obstructive pulmonary disease (0%) compared with Group B (53% and 14%, respectively). This may have led to fewer PPCs in Group C, but the difference was not significant. Despite Group C having fewer PPCs and less physiotherapy input, the number of days until discharge from physiotherapy and LOS were similar to Group B. The addition of deep breathing exercises to physiotherapy-directed early mobilisation did not further reduce PPCs compared with mobility alone. PPCs can be reduced with once-daily physiotherapy if the patients are mobilised to a moderate level of exertion. Delayed mobilisation tended to increase physiotherapy input and the number of days until discharge from physiotherapy

Effect of waveforms of inspired gas tension on the respiratory oscillations of carotid body discharge.

PubMed

Kumar, P; Nye, P C; Torrance, R W

1991-07-01

The responses of carotid body chemoreceptor discharge to repeated ramps (20- to 60-s forcing cycle durations) of inspired gas tensions were studied in spontaneously breathing and in artificially ventilated pentobarbitone-anesthetized cats. In all animals the mean intensity of chemoreceptor discharge followed the frequency of the forcing cycle, and superimposed on this were oscillations at the frequency of ventilation (breath-by-breath oscillations). The amplitude of the breath-by-breath oscillations in discharge was often large, and it waxed and waned with the forcing cycle. It was greatest when the mean level of discharge was falling and smallest near the peak of mean discharge. No qualitative differences were observed between PO2-alone forcing in constant normocapnia and PCO2-alone forcing in constant hypoxia. The variation in the amplitudes of breath-by-breath oscillations was shown to be due primarily to variations in the amplitudes of the downslope component of the discharge oscillation. Variations in the upslope component of individual oscillations were small. The factors responsible for the breath-by-breath oscillations are discussed, and it is concluded that the shape of the waveform of arterial gas tensions that stimulate the peripheral chemoreceptors departs markedly from that of a line joining end-tidal gas tensions. This causes breath-by-breath oscillations of discharge to be very large after an "off" stimulus. Reflex studies involving the forcing of respiratory gases should therefore include consideration of these effects.

Modeling of nanotherapeutics delivery based on tumor perfusion

PubMed Central

van de Ven, Anne L.; Abdollahi, Behnaz; Martinez, Carlos J.; Burey, Lacey A.; Landis, Melissa D.; Chang, Jenny C.; Ferrari, Mauro; Frieboes, Hermann B.

2013-01-01

Heterogeneities in the perfusion of solid tumors prevent optimal delivery of nanotherapeutics. Clinical imaging protocols to obtain patient-specific data have proven difficult to implement. It is challenging to determine which perfusion features hold greater prognostic value and to relate measurements to vessel structure and function. With the advent of systemically administered nanotherapeutics, whose delivery is dependent on overcoming diffusive and convective barriers to transport, such knowledge is increasingly important. We describe a framework for the automated evaluation of vascular perfusion curves measured at the single vessel level. Primary tumor fragments, collected from triple-negative breast cancer patients and grown as xenografts in mice, were injected with fluorescence contrast and monitored using intravital microscopy. The time to arterial peak and venous delay, two features whose probability distributions were measured directly from time-series curves, were analyzed using a Fuzzy C-mean (FCM) supervised classifier in order to rank individual tumors according to their perfusion characteristics. The resulting rankings correlated inversely with experimental nanoparticle accumulation measurements, enabling modeling of nanotherapeutics delivery without requiring any underlying assumptions about tissue structure or function, or heterogeneities contained within. With additional calibration, these methodologies may enable the study of nanotherapeutics delivery strategies in a variety of tumor models. PMID:24039540

Modeling of nanotherapeutics delivery based on tumor perfusion

NASA Astrophysics Data System (ADS)

van de Ven, Anne L.; Abdollahi, Behnaz; Martinez, Carlos J.; Burey, Lacey A.; Landis, Melissa D.; Chang, Jenny C.; Ferrari, Mauro; Frieboes, Hermann B.

2013-05-01

Heterogeneities in the perfusion of solid tumors prevent optimal delivery of nanotherapeutics. Clinical imaging protocols for obtaining patient-specific data have proven difficult to implement. It is challenging to determine which perfusion features hold greater prognostic value and to relate measurements to vessel structure and function. With the advent of systemically administered nanotherapeutics whose delivery is dependent on overcoming diffusive and convective barriers to transport, such knowledge is increasingly important. We describe a framework for the automated evaluation of vascular perfusion curves measured at the single vessel level. Primary tumor fragments, collected from triple-negative breast cancer patients and grown as xenografts in mice, were injected with fluorescence contrast and monitored using intravital microscopy. The time to arterial peak and venous delay, two features whose probability distributions were measured directly from time-series curves, were analyzed using a fuzzy c-mean supervised classifier in order to rank individual tumors according to their perfusion characteristics. The resulting rankings correlated inversely with experimental nanoparticle accumulation measurements, enabling the modeling of nanotherapeutics delivery without requiring any underlying assumptions about tissue structure or function, or heterogeneities contained therein. With additional calibration, these methodologies may enable the investigation of nanotherapeutics delivery strategies in a variety of tumor models.

Rate of disappearance of labeled carbon dioxide from the lungs of humans during breath holding: a method for studying the dynamics of pulmonary CO2 exchange

PubMed Central

Hyde, Richard W.; Puy, Ricardo J. M.; Raub, William F.; Forster, Robert E.

1968-01-01

The dynamics of CO2 exchange in the lungs of man was studied by observing the rate of disappearance of a stable isotope of CO2 (13CO2) from the alveolar gas during breath holding. Over 50% of the inspired isotope disappeared within the first 3 sec followed by a moderately rapid logarithmic decline in which one-half of the remaining 13CO2 disappeared every 10 sec. The large initial disappearance of 13CO2 indicated that alveolar 13CO2 equilibrated in less than 3 sec with the CO2 stored in the pulmonary tissues and capillary blood. The volume of CO2 in the pulmonary tissues calculated from this initial disappearance was 200 ml or 0.33 ml of CO2 per milliliter of pulmonary tissue volume. The alveolar to end-capillary gradient for 13CO2 was calculated by comparing the simultaneous disappearance rates of 13CO2 and acetylene. At rest and during exercise this gradient for 13CO2 was either very small or not discernible, and diffusing capacity for CO2 (DLCO2) exceeded 200 ml/(min × mm Hg). After the administration of a carbonic anhydrase inhibitor the rate of disappearance of 13CO2 decreased markedly. DLCO2 fell to 42 ml/(min × mm Hg) and at least 70% of the exchange of 13CO2 with the CO2 stores in the pulmonary tissues and blood was blocked by the inhibitor. These changes were attributed to impairment of exchange of 13CO2 with the bicarbonate in the pulmonary tissues and blood. The pH of the pulmonary tissues (Vtis) was determined by a method based on the premise that the CO2 space in the pulmonary tissues blocked by the inhibitor represented total bicarbonate content. At an alveolar PCO2 of 40 mm Hg pH of Vtis equalled 6.97 ± 0.09. PMID:5658586

Measurement of Venous Blood Flow in the Lower Limbs: Prevention of Deep Vein Thrombosis during Prolonged Sitting

DTIC Science & Technology

2004-06-01

Abstract. The venous blood flow during stretching and deep breathing in the sitting posture was examined in the present study. First, an...increase in the venous return. Therefore, we suggest that stretching and deep breathing can be used sometimes as preventive measures for deep vein...thrombosis during prolonged sitting. Keywords. Venous blood flow, Near infrared spectroscopy, Deep vein thrombosis. 1. Introduction It has been

Breathing pattern and breathlessness in idiopathic pulmonary fibrosis: An observational study.

PubMed

Olukogbon, Kasope L; Thomas, Paul; Colasanti, Ricardo; Hope-Gill, Ben; Williams, Edgar Mark

2016-02-01

Idiopathic pulmonary fibrosis (IPF) is characterized by progressive decline in lung function and increasing dyspnoea. The aim of this study was to investigate the relationship among IPF, pulmonary function, resting tidal breathing patterns and level of breathlessness. Thirty-one participants with IPF and 17 matched healthy controls underwent lung function testing, followed by a 2-min period of resting tidal breathing. The IPF cohort was stratified according to disease severity, based on their forced vital capacity and diffusion capacity for carbon monoxide. In comparison to the healthy controls, the IPF cohort showed a higher tidal volume, VT , of 0.22 L (P = 0.026) and a raised minute ventilation in the severest IPF group, while no differences in the timing of inspiration or expiration were observed. In the IPF cohort, the ratio of VT to forced vital capacity was around 15% higher. These changes corresponded with an increase in the self-reported sensation of breathlessness. Those with IPF increased their depth of breathing with worsening disease severity, with IPF-induced changes in pulmonary function and breathlessness associated with an altered tidal breathing pattern. © 2015 Asian Pacific Society of Respirology.

Hierarchy of orofacial rhythms revealed through whisking and breathing

PubMed Central

Moore, Jeffrey D.; Deschênes, Martin; Furuta, Takahiro; Huber, Daniel; Smear, Matthew C.; Demers, Maxime; Kleinfeld, David

2014-01-01

Whisking and sniffing are predominant aspects of exploratory behavior in rodents, yet the neural mechanisms that generate their motor patterns remain largely uncharacterized. We use anatomical, behavioral, electrophysiological, and pharmacological tools to demonstrate that these patterns are coordinated by respiratory centers in the ventral medulla. We delineate a distinct region in the ventral medulla that provides rhythmic input to the facial motoneurons that drive protraction of the vibrissae. Neuronal output from this region is reset at each inspiration by direct input from the preBötzinger complex, such that high frequency sniffing has a one-to-one coordination with whisking while basal respiration is accompanied by intervening whisks that occur between breaths. We conjecture that the respiratory nuclei, which project to other premotor regions for oral and facial control, function as a master clock for behaviors that coordinate with breathing. PMID:23624373

Cold therapy for the management of pain associated with deep breathing and coughing post-cardiac surgery.

PubMed

Chailler, Myrianne; Ellis, Jacqueline; Stolarik, Anne; Woodend, Kirsten

2010-01-01

Coughing has been identified as the most painful experience post cardiac surgery. Participants (n = 32), in a randomized crossover trial, applied a frozen gel pack to their sternal incision dressing before performing deep breathing and coughing (DB & C) exercises. Pain scores from 0 to 10 at rest were compared with pain scores post DB & C with and without the gel pack. Participants were also asked to describe their sensations with the frozen gel pack, as well as their preferences for gel pack application. The repeated measures analysis of variance revealed a significant reduction in pain scores between pre- and post-application of the gel pack (F = 28.69, p < .001). There were 22 (69%) participants who preferred the application of the gel pack compared with no gel pack. All 32 (100%) participants would reapply the gel pack in the future. This study demonstrates that cold therapy can be used to manage sternal incisional pain when DB & C.

Reprint of "Learning to breathe? Feedforward regulation of the inspiratory motor drive".

PubMed

Zaman, Jonas; Van den Bergh, Omer; Fannes, Stien; Van Diest, Ilse

2014-12-01

Claims have been made that breathing is in part controlled by feedforward regulation. In a classical conditioning paradigm, we investigated anticipatory increases in the inspiratory motor drive as measured by inspiratory occlusion pressure (P100). In an acquisition phase, an experimental group (N = 13) received a low-intensity resistive load (5 cmH2O/l/s) for three consecutive inspirations as Conditioned Stimulus (CS), preceding a load of a stronger intensity (20 cmH2O/l/s) for three subsequent inspirations as unconditioned stimulus (US). The control group (N = 11) received the low-intensity load for six consecutive inspirations. In a post-acquisition phase both groups received the low-intensity load for six consecutive inspirations. Responses to the CS-load only differed between groups during the first acquisition trials and a strong increase in P100 during the US-loads was observed, which habituated across the experiment. Our results suggest that the disruption caused by adding low to moderate resistive loads to three consecutive inspirations results in a short-lasting anticipatory increase in inspiratory motor drive. Copyright © 2014 Elsevier B.V. All rights reserved.

Anatomic study of the vascular perfusion of the sternum and its clinical relevance in deep sternal wound infection.

PubMed

Spindler, Nick; Kaatz, Florian; Feja, Christine; Etz, Christian; Mohr, Friedrich-Wilhelm; Bechmann, Ingo; Josten, Christoph; Langer, Stefan; Loeffler, Sabine

2017-01-01

Introduction: Deep sternal wound infections (DSWI) are a rare but devastating complication after median sternotomy. Minor perfusion in bone and soft tissue, especially after recruiting the internal mammary artery for bypass supports the development of wound infection and nonunion of the sternal bone. The aim of the study was the macroscopic and radiological presentation of the vascular system supplying the sternum, in particular the compensating blood supply routes in the event that the internal mammary artery is no longer available after use as a bypass vessel. Method: This anatomic study was carried out on the anterior chest wall of 7 specimens. The thorax plates of 7 specimens were analyzed macroscopically after microsurgical preparation. Different anatomic preparations were produced using different contrast or form-giving substances. Radiological analysis and three-dimensional reconstructions were performed to show alternative, collateral sternal vessel perfusion under estimation of the loss of the internal thoracic artery due to a bypass. Results: The length of the ITA (internal thoracic artery), measured from the beginning of the first rib to the division into the superior epigastric artery and musculophrenic artery, was an average of 16.3 cm. On average, 18.5 branches were delivered from each artery, 10 medially to the sternum supply, and 8 to the intercostal muscle. Conclusion: Our analysis gives an overview of the macroanatomic vessel system supplying the sternal bone, describing especially a common trunk deriving from the ITA and supplying multiple branches and playing an important role in building a collateral circulation of the sternum. For better evaluation, in vivo CT analysis with contrast media should be performed in patients prior to the operation and directly after the use of the double ITA to demonstrate the change in perfusion of the sternum. In the future, preconditioning of the sternum by coiling the deriving branches could become an option

Radial Ultrashort TE Imaging Removes the Need for Breath-Holding in Hepatic Iron Overload Quantification by R2* MRI.

PubMed

Tipirneni-Sajja, Aaryani; Krafft, Axel J; McCarville, M Beth; Loeffler, Ralf B; Song, Ruitian; Hankins, Jane S; Hillenbrand, Claudia M

2017-07-01

The objective of this study is to evaluate radial free-breathing (FB) multiecho ultrashort TE (UTE) imaging as an alternative to Cartesian FB multiecho gradient-recalled echo (GRE) imaging for quantitative assessment of hepatic iron content (HIC) in sedated patients and subjects unable to perform breath-hold (BH) maneuvers. FB multiecho GRE imaging and FB multiecho UTE imaging were conducted for 46 test group patients with iron overload who could not complete BH maneuvers (38 patients were sedated, and eight were not sedated) and 16 control patients who could complete BH maneuvers. Control patients also underwent standard BH multiecho GRE imaging. Quantitative R2* maps were calculated, and mean liver R2* values and coefficients of variation (CVs) for different acquisitions and patient groups were compared using statistical analysis. FB multiecho GRE images displayed motion artifacts and significantly lower R2* values, compared with standard BH multiecho GRE images and FB multiecho UTE images in the control cohort and FB multiecho UTE images in the test cohort. In contrast, FB multiecho UTE images produced artifact-free R2* maps, and mean R2* values were not significantly different from those measured by BH multiecho GRE imaging. Motion artifacts on FB multiecho GRE images resulted in an R2* CV that was approximately twofold higher than the R2* CV from BH multiecho GRE imaging and FB multiecho UTE imaging. The R2* CV was relatively constant over the range of R2* values for FB multiecho UTE, but it increased with increases in R2* for FB multiecho GRE imaging, reflecting that motion artifacts had a stronger impact on R2* estimation with increasing iron burden. FB multiecho UTE imaging was less motion sensitive because of radial sampling, produced excellent image quality, and yielded accurate R2* estimates within the same acquisition time used for multiaveraged FB multiecho GRE imaging. Thus, FB multiecho UTE imaging is a viable alternative for accurate HIC assessment

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.

Breath biomarkers for lung cancer detection and assessment of smoking related effects--confounding variables, influence of normalization and statistical algorithms.

PubMed

Kischkel, Sabine; Miekisch, Wolfram; Sawacki, Annika; Straker, Eva M; Trefz, Phillip; Amann, Anton; Schubert, Jochen K

2010-11-11

Up to now, none of the breath biomarkers or marker sets proposed for cancer recognition has reached clinical relevance. Possible reasons are the lack of standardized methods of sampling, analysis and data processing and effects of environmental contaminants. Concentration profiles of endogenous and exogenous breath markers were determined in exhaled breath of 31 lung cancer patients, 31 smokers and 31 healthy controls by means of SPME-GC-MS. Different correcting and normalization algorithms and a principal component analysis were applied to the data. Differences of exhalation profiles in cancer and non-cancer patients did not persist if physiology and confounding variables were taken into account. Smoking history, inspired substance concentrations, age and gender were recognized as the most important confounding variables. Normalization onto PCO2 or BSA or correction for inspired concentrations only partially solved the problem. In contrast, previous smoking behaviour could be recognized unequivocally. Exhaled substance concentrations may depend on a variety of parameters other than the disease under investigation. Normalization and correcting parameters have to be chosen with care as compensating effects may be different from one substance to the other. Only well-founded biomarker identification, normalization and data processing will provide clinically relevant information from breath analysis. 2010 Elsevier B.V. All rights reserved.

Quantitative myocardial perfusion from static cardiac and dynamic arterial CT

NASA Astrophysics Data System (ADS)

Bindschadler, Michael; Branch, Kelley R.; Alessio, Adam M.

2018-05-01

Quantitative myocardial blood flow (MBF) estimation by dynamic contrast enhanced cardiac computed tomography (CT) requires multi-frame acquisition of contrast transit through the blood pool and myocardium to inform the arterial input and tissue response functions. Both the input and the tissue response functions for the entire myocardium are sampled with each acquisition. However, the long breath holds and frequent sampling can result in significant motion artifacts and relatively high radiation dose. To address these limitations, we propose and evaluate a new static cardiac and dynamic arterial (SCDA) quantitative MBF approach where (1) the input function is well sampled using either prediction from pre-scan timing bolus data or measured from dynamic thin slice ‘bolus tracking’ acquisitions, and (2) the whole-heart tissue response data is limited to one contrast enhanced CT acquisition. A perfusion model uses the dynamic arterial input function to generate a family of possible myocardial contrast enhancement curves corresponding to a range of MBF values. Combined with the timing of the single whole-heart acquisition, these curves generate a lookup table relating myocardial contrast enhancement to quantitative MBF. We tested the SCDA approach in 28 patients that underwent a full dynamic CT protocol both at rest and vasodilator stress conditions. Using measured input function plus single (enhanced CT only) or plus double (enhanced and contrast free baseline CT’s) myocardial acquisitions yielded MBF estimates with root mean square (RMS) error of 1.2 ml/min/g and 0.35 ml/min/g, and radiation dose reductions of 90% and 83%, respectively. The prediction of the input function based on timing bolus data and the static acquisition had an RMS error compared to the measured input function of 26.0% which led to MBF estimation errors greater than threefold higher than using the measured input function. SCDA presents a new, simplified approach for quantitative

Cortical drive to breathe in amyotrophic lateral sclerosis: a dyspnoea-worsening defence?

PubMed

Georges, Marjolaine; Morawiec, Elise; Raux, Mathieu; Gonzalez-Bermejo, Jésus; Pradat, Pierre-François; Similowski, Thomas; Morélot-Panzini, Capucine

2016-06-01

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease causing diaphragm weakness that can be partially compensated by inspiratory neck muscle recruitment. This disappears during sleep, which is compatible with a cortical contribution to the drive to breathe. We hypothesised that ALS patients with respiratory failure exhibit respiratory-related cortical activity, relieved by noninvasive ventilation (NIV) and related to dyspnoea.We studied 14 ALS patients with respiratory failure. Electroencephalographic recordings (EEGs) and electromyographic recordings of inspiratory neck muscles were performed during spontaneous breathing and NIV. Dyspnoea was evaluated using the Multidimensional Dyspnea Profile.Eight patients exhibited slow EEG negativities preceding inspiration (pre-inspiratory potentials) during spontaneous breathing. Pre-inspiratory potentials were attenuated during NIV (p=0.04). Patients without pre-inspiratory potentials presented more advanced forms of ALS and more severe respiratory impairment, but less severe dyspnoea. Patients with pre-inspiratory potentials had stronger inspiratory neck muscle activation and more severe dyspnoea during spontaneous breathing.ALS-related diaphragm weakness can engage cortical resources to augment the neural drive to breathe. This might reflect a compensatory mechanism, with the intensity of dyspnoea a negative consequence. Disease progression and the corresponding neural loss could abolish this phenomenon. A putative cognitive cost should be investigated. Copyright ©ERS 2016.

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

Parental attitude, depression, anxiety in mothers, family functioning and breath-holding spells: A case control study.

PubMed

Eliacik, Kayi; Bolat, Nurullah; Kanik, Ali; Sargin, Enis; Selkie, Ellen; Korkmaz, Nurhan; Baydan, Figen; Akar, Ebru; Sarioglu, Berrak

2016-05-01

This study aimed to identify differences in the antenatal stressful life events, parenting style, family functioning, depression and anxiety of mothers who have children with breath-holding spells (BHS) compared with controls. This case control study divided 66 children into a group of children with BHS and a control group, with the children's ages ranging between 6 months and 5 years of age. This study explored underlying anxiety and depression in mothers as well as functioning of their families. Socio-demographical data and stressful life events that the mother experienced during pregnancy were analysed. In order to evaluate the effects of family structure, depression and anxiety in mothers on BHS in children, the Family Assessment Device, and both the Parental Attitude Research Instrument and the Beck Depression Inventory as well as the State-Trait Anxiety Inventory were used to assess both groups. Exposure to stressful life events during pregnancy (P < 0.001), depressive traits (P < 0.001), state-trait anxiety (P < 0.001), overprotective maternal characteristics (P = 0.027) and most of the family functioning subscales were found to be significantly different between BHS and control groups. The association of anxiety, depression, prenatal stressful events and poor family functioning in mothers who have children with BHS is significantly higher than controls. An evaluation of these problems may be beneficial in the management of BHS. © 2016 The Authors. Journal of Paediatrics and Child Health © 2016 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Combined effects of inspired oxygen, carbon dioxide, and carbon monoxide on oxygen transport and aerobic capacity.

PubMed

Crocker, George H; Toth, Balazs; Jones, James H

2013-09-01

We hypothesized that breathing hypoxic, hypercapnic, and CO-containing gases together reduces maximal aerobic capacity (Vo2max) as the sum of each gas' individual effect on Vo2max. To test this hypothesis, goats breathed combinations of inspired O2 fraction (FiO2) of 0.06-0.21 and inspired CO2 fraction of 0.00 or 0.05, with and without inspired CO that elevated carboxyhemoglobin fraction (FHbCO) to 0.02-0.45, while running on a treadmill at speeds eliciting Vo2max. Individually, hypoxia and elevated FHbCO decreased fractional Vo2max (FVo2max, fraction of a goat's Vo2max breathing air) in linear, dose-dependent manners; hypercapnia did not change Vo2max. Concomitant hypoxia and elevated FHbCO decreased Vo2max less than the individual gas effects summed, indicating their combined effects on Vo2max are attenuated, fitting the following regression: FVo2max = 4.24 FiO2 + 0.519 FHbCO - 8.22 (FiO2 × FHbCO) + 0.117, (R(2) = 0.965, P < 0.001). The FVo2max correlated highly with total cardiopulmonary O2 delivery, not peripheral diffusing capacity, and with arterial O2 concentration (CaO2), not cardiac output. Hypoxia and elevated FHbCO decreased CaO2 by different mechanisms: hypoxia decreased arterial O2 saturation (SaO2), whereas elevated FHbCO decreased O2 capacitance {concentration of hemoglobin (Hb) available to bind O2 ([Hbavail])}. When breathing hypoxic gas (FiO2 0.12), CaO2 did not change with increasing FHbCO up to 0.30 because higher SaO2 of Hbavail offset decreased [Hbavail] due to the following: 1) hyperventilation with hypoxia and/or elevated FHbCO; 2) increased Hb affinity for O2 due to both Bohr and direct carboxyhemoglobin effects; and 3) the sigmoid relationship between O2 saturation and partial pressure elevating SaO2 more with hypoxia than normoxia.

Myocardial perfusion characteristics during machine perfusion for heart transplantation.

PubMed

Peltz, Matthias; Cobert, Michael L; Rosenbaum, David H; West, LaShondra M; Jessen, Michael E

2008-08-01

Optimal parameters for machine perfusion preservation of hearts prior to transplantation have not been determined. We sought to define regional myocardial perfusion characteristics of a machine perfusion device over a range of conditions in a large animal model. Dog hearts were connected to a perfusion device (LifeCradle, Organ Transport Systems, Inc, Frisco, TX) and cold perfused at differing flow rates (1) at initial device startup and (2) over the storage interval. Myocardial perfusion was determined by entrapment of colored microspheres. Myocardial oxygen consumption (MVO(2)) was estimated from inflow and outflow oxygen differences. Intra-myocardial lactate was determined by (1)H magnetic resonance spectroscopy. MVO(2) and tissue perfusion increased up to flows of 15 mL/100 g/min, and the ratio of epicardial:endocardial perfusion remained near 1:1. Perfusion at lower flow rates and when low rates were applied during startup resulted in decreased capillary flow and greater non-nutrient flow. Increased tissue perfusion correlated with lower myocardial lactate accumulation but greater edema. Myocardial perfusion is influenced by flow rates during device startup and during the preservation interval. Relative declines in nutrient flow at low flow rates may reflect greater aortic insufficiency. These factors may need to be considered in clinical transplant protocols using machine perfusion.

Improving the Diagnostic Specificity of CT for Early Detection of Lung Cancer: 4D CT-Based Pulmonary Nodule Elastometry

DTIC Science & Technology

2015-10-01

malignant PNs treated with stereotactic ablative radiotherapy ( SABR ) with those of the lung. Methods: We analyzed breath-hold images of 30...patients with malignant PNs who underwent SABR in our department. A parametric nonrigid transformation model based on multi-level B-spline guided by Sum of...and 50 of 4D CT and deep inhale and natural exhale of breath-hold CT images of 30 MPN treated with stereotactic ablative radiotherapy ( SABR ). The

Retrospective 4D MR image construction from free-breathing slice Acquisitions: A novel graph-based approach.

PubMed

Tong, Yubing; Udupa, Jayaram K; Ciesielski, Krzysztof C; Wu, Caiyun; McDonough, Joseph M; Mong, David A; Campbell, Robert M

2017-01-01

comparison to a method called Random Stacking - a 4D phantom study and 10 4D MRI acquisitions from TIS patients and normal subjects. The 4D phantom was constructed by 3D printing the pleural spaces of an adult thorax, which were segmented in a breath-held MRI acquisition. Qualitative visual inspection via cine display of the slices in space and time and in 3D rendered form showed smooth variation for all data sets constructed by the proposed method. Quantitative evaluation was carried out to measure spatial and temporal contiguity of the slices via segmented pleural spaces. The optimal method showed smooth variation of the pleural space as compared to Random Stacking whose behavior was erratic. The volumes of the pleural spaces at the respiratory phase corresponding to end inspiration and end expiration were compared to volumes obtained from breath-hold acquisitions at roughly the same phase. The mean difference was found to be roughly 3%. The proposed method is purely image-based and post-hoc and does not need breath holding or external surrogates or instruments to record respiratory motion or tidal volume. This is important and practically warranted for pediatric patients. The constructed 4D images portray spatial and temporal smoothness that should be expected in a consistent 4D volume. We believe that the method can be routinely used for thoracic 4D imaging. Copyright © 2016 Elsevier B.V. All rights reserved.

Negative pressure ventilation decreases inflammation and lung edema during normothermic ex-vivo lung perfusion.

PubMed

Aboelnazar, Nader S; Himmat, Sayed; Hatami, Sanaz; White, Christopher W; Burhani, Mohamad S; Dromparis, Peter; Matsumura, Nobutoshi; Tian, Ganghong; Dyck, Jason R B; Mengel, Michael; Freed, Darren H; Nagendran, Jayan

2018-04-01

Normothermic ex-vivo lung perfusion (EVLP) using positive pressure ventilation (PPV) and both acellular and red blood cell (RBC)-based perfusate solutions have increased the rate of donor organ utilization. We sought to determine whether a negative pressure ventilation (NPV) strategy would improve donor lung assessment during EVLP. Thirty-two pig lungs were perfused ex vivo for 12 hours in a normothermic state, and were allocated equally to 4 groups according to the mode of ventilation (positive pressure ventilation [PPV] vs NPV) and perfusate composition (acellular vs RBC). The impact of ventilation strategy on the preservation of 6 unutilized human donor lungs was also evaluated. Physiologic parameters, cytokine profiles, lung injury, bullae and edema formation were compared between treatment groups. Perfused lungs demonstrated acceptable oxygenation (partial pressure of arterial oxygen/fraction of inspired oxygen ratio >350 mm Hg) and physiologic parameters. However, there was less generation of pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-6 and interleukin-8) in human and pig lungs perfused, irrespective of perfusate solution used, when comparing NPV with PPV (p < 0.05), and a reduction in bullae formation with an NPV modality (p = 0.02). Pig lungs developed less edema with NPV (p < 0.01), and EVLP using an acellular perfusate solution had greater edema formation, irrespective of ventilation strategy (p = 0.01). Interestingly, human lungs perfused with NPV developed negative edema, or "drying" (p < 0.01), and lower composite acute lung injury (p < 0.01). Utilization of an NPV strategy during extended EVLP is associated with significantly less inflammation, and lung injury, irrespective of perfusate solution composition. Copyright © 2018 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Prospective comparative study of brain protection in total aortic arch replacement: deep hypothermic circulatory arrest with retrograde cerebral perfusion or selective antegrade cerebral perfusion.

PubMed

Okita, Y; Minatoya, K; Tagusari, O; Ando, M; Nagatsuka, K; Kitamura, S

2001-07-01

The purpose of this study was to compare the results of total aortic arch replacement using two different methods of brain protection, particularly with respect to neurologic outcome. From June 1997, 60 consecutive patients who underwent total arch replacement through a midsternotomy were alternately allocated to one of two methods of brain protection: deep hypothermic circulatory arrest with retrograde cerebral perfusion (RCP: 30 patients) or with selective antegrade cerebral perfusion (SCP: 30 patients). Preoperative and postoperative (3 weeks) brain CT scan, neurological examination, and cognitive function tests were performed. Serum 100b protein was assayed before and after the cardiopulmonary bypass, as well as 24 hours and 48 hours after the operation. Hospital mortality occurred in 2 patients in the RCP group (6.6%) and 2 in the SCP group (6.6%). New strokes occurred in 1 (3.3%) of the RCP group and in 2 (6.6%) of the SCP group (p = 0.6). The incidence of transient brain dysfunction was significantly higher in the RCP group than in the SCP group (10, 33.3% vs 4, 13.3%, p = 0.05). Except in patients with strokes, S-100b values showed no significant differences in the two groups (RCP: SCP, prebypass 0.01+/-0.04: 0.05+/-0.16, postbypass 2.17+/-0.94: 1.97+/-1.00, 24 hours 0.61+/-0.36: 0.60+/-0.37, 48 hours 0.36+/-0.45: 0.46+/-0.40 microg/L, p = 0.7). There were no intergroup differences in the scores of memory decline (RCP 0.74+/-0.99; SCP 0.55+/-1.19, p = 0.6), orientation (RCP 1.11+/-1.29; SCP 0.50+/-0.76, p = 0.08), or intellectual function (RCP 1.21+/-1.27; SCP 1.05+/-1.15, p = 0.7). Both methods of brain protection for patients undergoing total arch replacement resulted in acceptable levels of mortality and morbidity. However, the prevalence of transient brain dysfunction was significantly higher in patients with the RCP.

Perfusion flow bioreactor for 3D in situ imaging: investigating cell/biomaterials interactions.

PubMed

Stephens, J S; Cooper, J A; Phelan, F R; Dunkers, J P

2007-07-01

The capability to image real time cell/material interactions in a three-dimensional (3D) culture environment will aid in the advancement of tissue engineering. This paper describes a perfusion flow bioreactor designed to hold tissue engineering scaffolds and allow for in situ imaging using an upright microscope. The bioreactor can hold a scaffold of desirable thickness for implantation (>2 mm). Coupling 3D culture and perfusion flow leads to the creation of a more biomimetic environment. We examined the ability of the bioreactor to maintain cell viability outside of an incubator environment (temperature and pH stability), investigated the flow features of the system (flow induced shear stress), and determined the image quality in order to perform time-lapsed imaging of two-dimensional (2D) and 3D cell culture. In situ imaging was performed on 2D and 3D, culture samples and cell viability was measured under perfusion flow (2.5 mL/min, 0.016 Pa). The visualization of cell response to their environment, in real time, will help to further elucidate the influences of biomaterial surface features, scaffold architectures, and the influence of flow induced shear on cell response and growth of new tissue. (c) 2006 Wiley Periodicals, Inc.

SU-E-T-18: A Comparison of Planning Techniques for Bilateral Reconstructed Chest Wall Patients Undergoing Whole Breast Irradiation

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

Volpe, T; Margiasso, R; Saleh, Z

2015-06-15

Purpose: As we continuously see more bilateral reconstructed chest wall cases, new challenges are being presented to deliver left-sided breast irradiation. We herein compare three Deep Inspiration Breath Hold (DIBH) planning techniques (tangents, VMAT, and IMRT) and two free breathing techniques (VMAT and IMRT). Methods: Three left-sided chest wall patients with bilateral implants were studied. Tangents, VMAT, and IMRT plans were created for DIBH scans. VMAT and IMRT plans were created for free breathing scans. All plans were normalized so that 95% of the prescription dose was delivered to 95% of the planning target volume (PTV). The maximum point dosemore » was constrained to less than 120% of the prescription dose. Since the success of DIBH delivery largely depends on patient’s ability to perform consistent breath hold during beam on time, smaller number of Monitor Units (MU) is in general desired. For each patient, the following information was collected to compare the planning techniques: heart mean dose, left and right lung V20 Gy, contra-lateral (right) breast mean dose, cord max dose, and MU. Results: The average heart mean dose over all patients are 1561, 692, 985, 1245, and 1121 cGy, for DIBH tangents, VMAT, IMRT, free breathing VMAT and IMRT, respectively. For left lung V20 are 60%, 28%, 26%, 30%, and 29%. For contra-lateral breast mean dose are 244, 687, 616, 783, 438 cGy. MU are 253, 853, 2048, 1035, and 1874 MUs. Conclusion: In the setting of bilateral chest wall reconstruction, opposed tangent beams cannot consistently achieve desired heart and left lung sparing. DIBH consistently achieves better healthy tissue sparing. VMAT appears to be preferential to IMRT for planning and delivering radiation to patients with bilaterally reconstructed chest walls being treated with DIBH.« less

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

Diaphragm breathing movement measurement using ultrasound and radiographic imaging: a concurrent validity.

PubMed

Noh, Dong K; Lee, Jae J; You, Joshua H

2014-01-01

Recent ultrasound imaging evidence asserts that the diaphragm is an important multifunctional muscle to control breathing as well as stabilize the core and posture in humans. However, the validity and accuracy of ultrasound for the measurement of dynamic diaphragm movements during breathing and functional core activities have not been determined. The specific aim of this study was to validate the accuracy of ultrasound imaging measurements of diaphragm movements by concurrently comparing these measurements to the gold standard of radiographic imaging measurements. A total of 14 asymptomatic adults (9 males, 5 females; mean age =28.4 ± 3.0 years) were recruited to participate in the study. Ultrasound and radiographic images were used concurrently to determine diaphragm movement (inspiration, expiration, and excursion) during tidal breathing. Pearson correlation analysis showed strong correlations, ranging from r=0.78 to r=0.83, between ultrasound and radiographic imaging measurements of the diaphragm during inhalation, exhalation, and excursion. These findings suggest that ultrasound imaging measurement is useful to accurately evaluate diaphragm movements during tidal breathing. Clinically, ultrasound imaging measurements can be used to diagnose and treat diaphragm movement impairments in individuals with neuromuscular disorders including spinal cord injuries, stroke, and multiple sclerosis.

Effect of upper costal and costo-diaphragmatic breathing types on electromyographic activity of respiratory muscles.

PubMed

Celhay, Isabel; Cordova, Rosa; Miralles, Rodolfo; Meza, Francisco; Erices, Pia; Barrientos, Camilo; Valenzuela, Saúl

2015-04-01

To compare electromyographic (EMG) activity in young-adult subjects with different breathing types. This study included 50 healthy male subjects with complete natural dentition, and no history of orofacial pain or craniomandibular-cervical-spinal disorders. Subjects were classified into two groups: upper costal breathing type, and costo-diaphragmatic breathing. Bipolar surface electrodes were located on sternocleidomastoid, diaphragm, external intercostal, and latissimus dorsi muscles. Electromyographic activity was recorded during the following tasks: (1) normal quiet breathing; (2) speaking the word 'Mississippi'; (3) swallowing saliva; and (4) forced deep breathing. Sternocleidomastoid and latissimus dorsi EMG activity was not significantly different between breathing types, whereas diaphragm and external intercostal EMG activity was significantly higher in the upper costal than costo-diaphragmatic breathing type in all tasks (P<0·05; Wilcoxon signed rank-sum test). Diaphragm and external intercostal EMG activity suggests that there could be differences in motor unit recruitment strategies depending on the breathing type.

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...

Code of Federal Regulations, 2010 CFR

2010-10-01

... closed-circuit apparatus; maximum allowable limits. 84.97 Section 84.97 Public Health PUBLIC HEALTH... ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.97 Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable limits. (a) Open...

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...

Code of Federal Regulations, 2011 CFR

2011-10-01

... closed-circuit apparatus; maximum allowable limits. 84.97 Section 84.97 Public Health PUBLIC HEALTH... ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.97 Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable limits. (a) Open...

Interfractional Dose Variations in Intensity-Modulated Radiotherapy With Breath-Hold for Pancreatic Cancer

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

Nakamura, Mitsuhiro; Shibuya, Keiko, E-mail: kei@kuhp.kyoto-u.ac.jp; Nakamura, Akira

2012-04-01

Purpose: To investigate the interfractional dose variations for intensity-modulated radiotherapy (RT) combined with breath-hold (BH) at end-exhalation (EE) for pancreatic cancer. Methods and Materials: A total of 10 consecutive patients with pancreatic cancer were enrolled. Each patient was fixed in the supine position on an individualized vacuum pillow with both arms raised. Computed tomography (CT) scans were performed before RT, and three additional scans were performed during the course of chemoradiotherapy using a conventional RT technique. The CT data were acquired under EE-BH conditions (BH-CT) using a visual feedback technique. The intensity-modulated RT plan, which used five 15-MV coplanar ports,more » was designed on the initial BH-CT set with a prescription dose of 39 Gy at 2.6 Gy/fraction. After rigid image registration between the initial and subsequent BH-CT scans, the dose distributions were recalculated on the subsequent BH-CT images under the same conditions as in planning. Changes in the dose-volume metrics of the gross tumor volume (GTV), clinical target volume (CTV = GTV + 5 mm), stomach, and duodenum were evaluated. Results: For the GTV and clinical target volume (CTV), the 95th percentile of the interfractional variations in the maximal dose, mean dose, dose covering 95% volume of the region of structure, and percentage of the volume covered by the 90% isodose line were within {+-}3%. Although the volume covered by the 39 Gy isodose line for the stomach and duodenum did not exceed 0.1 mL at planning, the volume covered by the 39 Gy isodose line for these structures was up to 11.4 cm{sup 3} and 1.8 cm{sup 3}, respectively. Conclusions: Despite variations in the gastrointestinal state and abdominal wall position at EE, the GTV and CTV were mostly ensured at the planned dose, with the exception of 1 patient. Compared with the duodenum, large variations in the stomach volume receiving high-dose radiation were observed, which might be beyond the

The perfused swine uterus model: long-term perfusion

PubMed Central

2012-01-01

Background It has previously been shown that the viability of swine uteri can be maintained within the physiological range in an open perfusion model for up to 8 hours. The aim of this study was to assess medium- to long-term perfusion of swine uteri using a modified Krebs–Ringer bicarbonate buffer solution (KRBB) in the established open perfusion model. Methods In an experimental study at an infertility institute, 30 swine uteri were perfused: group 1: n = 11, KRBB; group 2: n = 8, modified KRBB with drainage of perfusate supernatant; group 3: n = 11, modified KRBB with drainage of perfusate every 2 h and substitution with fresh medium. Modified and conventional KRBB were compared with regard to survival and contraction parameters: intrauterine pressure (IUP), area under the curve (AUC), and frequency of contractions (F). Results Modified KRBB showed significantly higher IUP, AUC, and F values than perfusion with conventional KRBB. In group 3, the organ survival time of up to 17 h, with a 98% rate of effective contraction time, differed significantly from group 1 (P < 0.001). Conclusions Using modified KRBB in combination with perfusate substitution improves the open model for perfusion of swine uteri with regard to survival time and quality of contraction parameters. This model can be used for medium- to long-term perfusion of swine uteri, allowing further metabolic ex vivo studies in a cost-effective way and with little logistic effort. PMID:23241226

Optogenetically inspired deep brain stimulation: linking basic with clinical research.

PubMed

Lüscher, Christian; Pollak, Pierre

2016-01-01

In the last decade, optogenetics has revolutionised the neurosciences. The technique, which allows for cell-type specific excitation and inhibition of neurons in the brain of freely moving rodents, has been used to tighten the links of causality between neural activity and behaviour. Optogenetics is also enabling an unprecedented characterisation of circuits and their dysfunction in a number of brain diseases, above all those conditions that are not caused by neurodegeneration. Notable progress has been made in addiction, depression and obsessive-compulsive disorders, as well as other anxiety disorders. By extension, the technique has also been used to propose blueprints for innovative rational treatment of these diseases. The goal is to design manipulations that disrupt pathological circuit function or restore normal activity. This can be achieved by targeting specific projections in order to apply specific stimulation protocols validated by ex-vivo analysis of the mechanisms underlying the dysfunction. In a number of cases, specific forms of pathological synaptic plasticity have been implicated. For example, addictive drugs via strong increase of dopamine trigger a myriad of alterations of glutamate and γ-aminobutyric acid transmission, also called drug-evoked synaptic plasticity. This opens the way to the design of optogenetic reversal protocols, which might restore normal transmission with the hope to abolish the pathological behaviour. Several proof of principle studies for this approach have recently been published. However, for many reasons, optogenetics will not be translatable to human applications in the near future. Here, we argue that an intermediate step is novel deep brain stimulation (DBS) protocols that emulate successful optogenetic approaches in animal models. We provide a roadmap for a translational path to rational, optogenetically inspired DBS protocols to refine existing approaches and expand to novel indications.

Similar cerebral protective effectiveness of antegrade and retrograde cerebral perfusion during deep hypothermic circulatory arrest in aortic surgery: a meta-analysis of 7023 patients.

PubMed

Guo, Shasha; Sun, Yanhua; Ji, Bingyang; Liu, Jinping; Wang, Guyan; Zheng, Zhe

2015-04-01

In aortic arch surgery, deep hypothermic circulatory arrest (DHCA) combined with cerebral perfusion is employed worldwide as a routine practice. Even though antegrade cerebral perfusion (ACP) is more widely used than retrograde cerebral perfusion (RCP), the difference in benefit and risk between ACP and RCP during DHCA is uncertain. The purpose of this meta-analysis is to compare neurologic outcomes and early mortality between ACP and RCP in patients who underwent aortic surgery during DHCA. PubMed, EMBASE, and the Cochrane Library were searched using the key words "antegrade," "retrograde," "cerebral perfusion," "cardiopulmonary bypass," "extracorporeal circulation," and "cardiac surgery" for studies reporting on clinical endpoints including early mortality, stroke, temporary neurologic dysfunction (TND), and permanent neurologic dysfunction (PND) in aortic surgery requiring DHCA with ACP or RCP. Heterogeneity was analyzed with the Cochrane Q statistic and I(2) statistic. Publication bias was tested with Begg's funnel plot and Egger's test. Thirty-four studies were included in this meta-analysis, with 4262 patients undergoing DHCA + ACP and 2761 undergoing DHCA + RCP. The overall pooled relative risk for TND was 0.722 (95% CI = [0.579, 0.900]), and the z-score for overall effect was 2.9 (P = 0.004). There was low heterogeneity (I(2) = 18.7%). The analysis showed that patients undergoing DHCA + ACP had better outcomes than those undergoing DHCA + RCP in terms of TND, while there were no significant differences between groups in terms of PND, stroke, and early mortality. This meta-analysis indicates that DHCA + ACP has an advantage over DHCA + RCP in terms of TND, while the two methods show similar results in terms of PND, early mortality, and stroke. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

The effect of consistent practice of yogic breathing exercises on the human cardiorespiratory system.

PubMed

McKay, Joshua A A; McCulloch, Cara L; Querido, Jordan S; Foster, Glen E; Koehle, Michael S; Sheel, A William

2016-11-01

The purpose of this investigation was to quantify the cardiovascular, respiratory, and cerebrovascular effects of two common yogic breathing exercises (YBE): bhastrika and chaturbhuj; and to determine the effect of their consistent practice on chemosensitivity. The first study was cross-sectional and compared experienced yogic breathers (YB) with matched controls; whereas the second was a 10-week longitudinal training study. The results support four major findings. First chaturbhuj resulted in a hypoxic stimulus in experienced YB compared to control [end-tidal oxygen tension (P ET O 2 ), YB: 77.5±5.7mmHg, P<0.05; control: 94.3±12.0mmHg]. Second, performance of chaturbhuj resulted in cyclic oscillations of mean arterial pressure (MAP), heart rate (HR), and middle cerebral artery velocity (MCAv) consistent with the phases of respiration. Third, post training, performance of bhastrika reduced P ET O 2 (end breath-hold: 90.8 8±12.1mmHg) compared to rest (100.1±7.4, P<0.05); it also resulted in significantly increased MAP at end breath-hold (96.7±13.0mmHg) compared to rest (83.0±6.6mmHg, P<0.05) and significantly increased mean MCAv (end breath-hold: 87.4±23.0cm/s, P<0.05; rest: 55.8±26.3cm/s). Fourth, experienced YB had lower central chemosensitivity than controls (YB: 3.4±0.4; control: 4.6±1.2L/min/mmHg; P<0.05). In conclusion, YBE significantly alter end-tidal gases, resulting in complex oscillations of cardiovascular and cerebrovascular variables, and if practiced consistently, may reduce chemosensitivity. Copyright © 2016. Published by Elsevier B.V.

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

Cicada-inspired cell-instructive nanopatterned arrays

NASA Astrophysics Data System (ADS)

Diu, Ting; Faruqui, Nilofar; Sjöström, Terje; Lamarre, Baptiste; Jenkinson, Howard F.; Su, Bo; Ryadnov, Maxim G.

2014-11-01

Biocompatible surfaces hold key to a variety of biomedical problems that are directly related to the competition between host-tissue cell integration and bacterial colonisation. A saving solution to this is seen in the ability of cells to uniquely respond to physical cues on such surfaces thus prompting the search for cell-instructive nanoscale patterns. Here we introduce a generic rationale engineered into biocompatible, titanium, substrates to differentiate cell responses. The rationale is inspired by cicada wing surfaces that display bactericidal nanopillar patterns. The surfaces engineered in this study are titania (TiO2) nanowire arrays that are selectively bactericidal against motile bacteria, while capable of guiding mammalian cell proliferation according to the type of the array. The concept holds promise for clinically relevant materials capable of differential physico-mechanical responses to cellular adhesion.

Cicada-inspired cell-instructive nanopatterned arrays.

PubMed

Diu, Ting; Faruqui, Nilofar; Sjöström, Terje; Lamarre, Baptiste; Jenkinson, Howard F; Su, Bo; Ryadnov, Maxim G

2014-11-20

Biocompatible surfaces hold key to a variety of biomedical problems that are directly related to the competition between host-tissue cell integration and bacterial colonisation. A saving solution to this is seen in the ability of cells to uniquely respond to physical cues on such surfaces thus prompting the search for cell-instructive nanoscale patterns. Here we introduce a generic rationale engineered into biocompatible, titanium, substrates to differentiate cell responses. The rationale is inspired by cicada wing surfaces that display bactericidal nanopillar patterns. The surfaces engineered in this study are titania (TiO2) nanowire arrays that are selectively bactericidal against motile bacteria, while capable of guiding mammalian cell proliferation according to the type of the array. The concept holds promise for clinically relevant materials capable of differential physico-mechanical responses to cellular adhesion.

Lung anatomy and histology of the extant coelacanth shed light on the loss of air-breathing during deep-water adaptation in actinistians.

PubMed

Cupello, Camila; Meunier, François J; Herbin, Marc; Clément, Gaël; Brito, Paulo M

2017-03-01

Lungs are specialized organs originated from the posterior pharyngeal cavity and considered as plesiomorphic for osteichthyans, as they are found in extant basal actinopterygians (i.e. Polypterus ) and in all major groups of extant sarcopterygians. The presence of a vestigial lung in adult stages of the extant coelacanth Latimeria chalumnae is the result of allometric growth during ontogeny, in relation with long-time adaptation to deep water. Here, we present the first detailed histological and anatomical description of the lung of Latimeria chalumnae , providing new insights into its arrested differentiation in an air-breathing complex, mainly represented by the absence of pneumocytes and of compartmentalization in the latest ontogenetic stages.

Similar cerebral protective effectiveness of antegrade and retrograde cerebral perfusion combined with deep hypothermia circulatory arrest in aortic arch surgery: a meta-analysis and systematic review of 5060 patients.

PubMed

Hu, Zhipeng; Wang, Zhiwei; Ren, Zongli; Wu, Hongbing; Zhang, Min; Zhang, Hao; Hu, Xiaoping

2014-08-01

Our objective was to determine if antegrade cerebral perfusion (ACP) and retrograde cerebral perfusion (RCP) combined with deep hypothermia circulatory arrest in aortic arch surgery results in different mortality and neurologic outcomes. The Cochrane Library, Medline, EMBASE, CINAHL, Web of Science, and the Chinese Biomedical Database were searched for studies reporting on postoperative strokes, permanent neurologic dysfunction, temporary neurologic dysfunction, and all causes mortality within 30 days postoperation in aortic arch surgery. Meta-analysis for effect size, t test, and I(2) for detecting heterogeneity and sensitivity analysis for assessing the relative influence of each study was performed. Fifteen included studies encompassed a total of 5060 patients of whom 2855 were treated with deep hypothermic circulatory arrest plus ACP and 1897 were treated with deep hypothermic circulatory arrest plus RCP. Pooled analysis showed no significant statistical difference (P > .01) of 30-day mortality, permanent neurologic dysfunction, and transient neurologic dysfunction in the 2 groups. Before sensitivity analysis, postoperative stroke incidence in the ACP group was higher than in the RCP group (7.2% vs 4.7%; P < .01). After a study that included a different percentage of patients with a history of central neurologic events in the 2 groups was ruled out, postoperative stroke incidence in the 2 groups also showed no significant statistical difference (P > .01). ACP and RCP provide similar cerebral protective effectiveness combined with deep hypothermia circulatory arrest and could be selected according to the actual condition in aortic arch surgery. A high-quality randomized controlled trial is urgently needed to confirm this conclusion, especially for stroke morbidity following ACP or RCP. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

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.

Conditioning of inspired air by a hygroscopic condenser humidifier.

PubMed

Primiano, F P; Moranz, M E; Montague, F W; Miller, R B; Sachs, D P

1984-08-01

The heat and water content of inspired air is critical to the pulmonary viability of patients with artificial airways. By continuously measuring gas conditions in the ventilator circuits of 6 adult ICU patients, we studied the heat and water reclaimed from expired air by a hygroscopic condenser humidifier (HCH) in the circuit. Temperature, partial pressure of water vapor (PH2O) and relative humidity (RH) were determined at the tracheal outlet of the endotracheal tube. The HCH was 63% efficient; the end-inspiratory gas delivered to the patients averaged 30.9 degrees C with a PH2O of 32.5 mm Hg and an RH of 97.3% or, equivalently, an RH of 69.2% referenced to 37 degrees C. These values are lower than those reported in the literature for gas in the trachea during nose breathing of ambient air, but greater than the values reported for mouth breathing of ambient air.

Three-Hour Dives with Exercise While Breathing Oxygen Partial Pressure of 1.3 ATM

DTIC Science & Technology

2007-10-01

after the breath hold. Adjustments were made for carboxyhemoglobin and hemoglobin concentrations,9 and the samples were chosen to ensure that the...CO and 0.3% methane. A CO oximeter (Instrumentation Laboratory; Lexington, MA) determined the pretest carboxyhemoglobin and hemoglobin concentrations

Within-breath respiratory impedance and airway obstruction in patients with chronic obstructive pulmonary disease.

PubMed

Silva, Karla Kristine Dames da; Faria, Alvaro Camilo Dias; Lopes, Agnaldo José; Melo, Pedro Lopes de

2015-07-01

Recent work has suggested that within-breath respiratory impedance measurements performed using the forced oscillation technique may help to noninvasively evaluate respiratory mechanics. We investigated the influence of airway obstruction on the within-breath forced oscillation technique in smokers and chronic obstructive pulmonary disease patients and evaluated the contribution of this analysis to the diagnosis of chronic obstructive pulmonary disease. Twenty healthy individuals and 20 smokers were assessed. The study also included 74 patients with stable chronic obstructive pulmonary disease. We evaluated the mean respiratory impedance (Zm) as well as values for the inspiration (Zi) and expiration cycles (Ze) at the beginning of inspiration (Zbi) and expiration (Zbe), respectively. The peak-to-peak impedance (Zpp=Zbe-Zbi) and the respiratory cycle dependence (ΔZrs=Ze-Zi) were also analyzed. The diagnostic utility was evaluated by investigating the sensitivity, the specificity and the area under the receiver operating characteristic curve. ClinicalTrials.gov: NCT01888705. Airway obstruction increased the within-breath respiratory impedance parameters that were significantly correlated with the spirometric indices of airway obstruction (R=-0.65, p<0.0001). In contrast to the control subjects and the smokers, the chronic obstructive pulmonary disease patients presented significant expiratory-inspiratory differences (p<0.002). The adverse effects of moderate airway obstruction were detected based on the Zpp with an accuracy of 83%. Additionally, abnormal effects in severe and very severe patients were detected based on the Zm, Zi, Ze, Zbe, Zpp and ΔZrs with a high degree of accuracy (>90%). We conclude the following: (1) chronic obstructive pulmonary disease introduces higher respiratory cycle dependence, (2) this increase is proportional to airway obstruction, and (3) the within-breath forced oscillation technique may provide novel parameters that facilitate the

Breath detection by transcutaneous electromyography of the diaphragm and the Graseby capsule in preterm infants.

PubMed

de Waal, Cornelia G; Kraaijenga, Juliette V; Hutten, Gerard J; de Jongh, Frans H; van Kaam, Anton H

2017-12-01

To compare triggering, breath detection and delay time of the Graseby capsule (GC) and transcutaneous electromyography of the diaphragm (dEMG) in spontaneous breathing preterm infants. In this observational study, a 30 minutes respiration measurement was conducted by respiratory inductance plethysmography (RIP), the GC, and dEMG in stable preterm infants. Triggering was investigated with an in vitro set-up using the Infant Flow ® SiPAP TM system. The possibility to optimize breath detection was tested by developing new algorithms with the abdominal RIP band (RIP AB ) as gold standard. In a subset of breaths, the delay time was calculated between the inspiratory onset in the RIP AB signal and in the GC and dEMG signal. Fifteen preterm infants with a mean gestational age of 28 ± 2 weeks and a mean birth weight of 1086 ± 317 g were included. In total, 14 773 breaths were analyzed. Based on the GC and dEMG signal, the Infant Flow ® SiPAP™ system, respectively, triggered 67.8% and 62.6% of the breaths. Breath detection was improved to 99.9% for the GC and 113.4% for dEMG in new algorithms. In 1492 stable breaths, the median delay time of inspiratory onset detection was +154 ms (IQR +118 to +164) in the GC and -50 ms (IQR -90 to -22) in the dEMG signal. Breath detection using the GC can be improved by optimizing the algorithm. Transcutaneous dEMG provides similar breath detection but with the advantage of detecting the onset of inspiration earlier than the GC. © 2017 Wiley Periodicals, Inc.

Perfusion-induced changes in cardiac contractility depend on capillary perfusion.

PubMed

Dijkman, M A; Heslinga, J W; Sipkema, P; Westerhof, N

1998-02-01

The perfusion-induced increase in cardiac contractility (Gregg phenomenon) is especially found in heart preparations that lack adequate coronary autoregulation and thus protection of changes in capillary pressure. We determined in the isolated perfused papillary muscle of the rat whether cardiac muscle contractility is related to capillary perfusion. Oxygen availability of this muscle is independent of internal perfusion, and perfusion may be varied or even stopped without loss of function. Muscles contracted isometrically at 27 degrees C (n = 7). During the control state stepwise increases in perfusion pressure resulted in all muscles in a significant increase in active tension. Muscle diameter always increased with increased perfusion pressure, but muscle segment length was unaffected. Capillary perfusion was then obstructed by plastic microspheres (15 microns). Flow, at a perfusion pressure of 66.6 +/- 26.2 cmH2O, reduced from 17.6 +/- 5.4 microliters/min in the control state to 3.2 +/- 1.3 microliters/min after microspheres. Active tension developed by the muscle in the unperfused condition before microspheres and after microspheres did not differ significantly (-12.8 +/- 29.4% change). After microspheres similar perfusion pressure steps as in control never resulted in an increase in active tension. Even at the two highest perfusion pressures (89.1 +/- 28.4 and 106.5 +/- 31.7 cmH2O) that were applied a significant decrease in active tension was found. We conclude that the Gregg phenomenon is related to capillary perfusion.

Clinical Feasibility of Free-Breathing Dynamic T1-Weighted Imaging With Gadoxetic Acid-Enhanced Liver Magnetic Resonance Imaging Using a Combination of Variable Density Sampling and Compressed Sensing.

PubMed

Yoon, Jeong Hee; Yu, Mi Hye; Chang, Won; Park, Jin-Young; Nickel, Marcel Dominik; Son, Yohan; Kiefer, Berthold; Lee, Jeong Min

2017-10-01

The purpose of the study was to investigate the clinical feasibility of free-breathing dynamic T1-weighted imaging (T1WI) using Cartesian sampling, compressed sensing, and iterative reconstruction in gadoxetic acid-enhanced liver magnetic resonance imaging (MRI). This retrospective study was approved by our institutional review board, and the requirement for informed consent was waived. A total of 51 patients at high risk of breath-holding failure underwent dynamic T1WI in a free-breathing manner using volumetric interpolated breath-hold (BH) examination with compressed sensing reconstruction (CS-VIBE) and hard gating. Timing, motion artifacts, and image quality were evaluated by 4 radiologists on a 4-point scale. For patients with low image quality scores (<3) on the late arterial phase, respiratory motion-resolved (extradimension [XD]) reconstruction was additionally performed and reviewed in the same manner. In addition, in 68.6% (35/51) patients who had previously undergone liver MRI, image quality and motion artifacts on dynamic phases using CS-VIBE were compared with previous BH-T1WIs. In all patients, adequate arterial-phase timing was obtained at least once. Overall image quality of free-breathing T1WI was 3.30 ± 0.59 on precontrast and 2.68 ± 0.70, 2.93 ± 0.65, and 3.30 ± 0.49 on early arterial, late arterial, and portal venous phases, respectively. In 13 patients with lower than average image quality (<3) on the late arterial phase, motion-resolved reconstructed T1WI (XD-reconstructed CS-VIBE) significantly reduced motion artifacts (P < 0.002-0.021) and improved image quality (P < 0.0001-0.002). In comparison with previous BH-T1WI, CS-VIBE with hard gating or XD reconstruction showed less motion artifacts and better image quality on precontrast, arterial, and portal venous phases (P < 0.0001-0.013). Volumetric interpolated breath-hold examination with compressed sensing has the potential to provide consistent, motion-corrected free-breathing dynamic T

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...

Code of Federal Regulations, 2013 CFR

2013-10-01

... machine. An acceptable method for measuring the concentration of carbon dioxide is described in Bureau of Mines Report of Investigations 6865, A Machine-Test Method for Measuring Carbon Dioxide in the Inspired... of 10.5 liters. (3) A sedentary breathing machine cam will be used. (4) The apparatus will be tested...

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...

Code of Federal Regulations, 2012 CFR

2012-10-01

... machine. An acceptable method for measuring the concentration of carbon dioxide is described in Bureau of Mines Report of Investigations 6865, A Machine-Test Method for Measuring Carbon Dioxide in the Inspired... of 10.5 liters. (3) A sedentary breathing machine cam will be used. (4) The apparatus will be tested...

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...

Code of Federal Regulations, 2014 CFR

2014-10-01

... machine. An acceptable method for measuring the concentration of carbon dioxide is described in Bureau of Mines Report of Investigations 6865, A Machine-Test Method for Measuring Carbon Dioxide in the Inspired... of 10.5 liters. (3) A sedentary breathing machine cam will be used. (4) The apparatus will be tested...

Air-breathing fishes in aquaculture. What can we learn from physiology?

PubMed

Lefevre, S; Wang, T; Jensen, A; Cong, N V; Huong, D T T; Phuong, N T; Bayley, M

2014-03-01

During the past decade, the culture of air-breathing fish species has increased dramatically and is now a significant global source of protein for human consumption. This development has generated a need for specific information on how to maximize growth and minimize the environmental effect of culture systems. Here, the existing data on metabolism in air-breathing fishes are reviewed, with the aim of shedding new light on the oxygen requirements of air-breathing fishes in aquaculture, reaching the conclusion that aquatic oxygenation is much more important than previously assumed. In addition, the possible effects on growth of the recurrent exposure to deep hypoxia and associated elevated concentrations of carbon dioxide, ammonia and nitrite, that occurs in the culture ponds used for air-breathing fishes, are discussed. Where data on air-breathing fishes are simply lacking, data for a few water-breathing species will be reviewed, to put the physiological effects into a growth perspective. It is argued that an understanding of air-breathing fishes' respiratory physiology, including metabolic rate, partitioning of oxygen uptake from air and water in facultative air breathers, the critical oxygen tension, can provide important input for the optimization of culture practices. Given the growing importance of air breathers in aquaculture production, there is an urgent need for further data on these issues. © 2014 The Fisheries Society of the British Isles.

Lung anatomy and histology of the extant coelacanth shed light on the loss of air-breathing during deep-water adaptation in actinistians

PubMed Central

Meunier, François J.; Herbin, Marc; Clément, Gaël; Brito, Paulo M.

2017-01-01

Lungs are specialized organs originated from the posterior pharyngeal cavity and considered as plesiomorphic for osteichthyans, as they are found in extant basal actinopterygians (i.e. Polypterus) and in all major groups of extant sarcopterygians. The presence of a vestigial lung in adult stages of the extant coelacanth Latimeria chalumnae is the result of allometric growth during ontogeny, in relation with long-time adaptation to deep water. Here, we present the first detailed histological and anatomical description of the lung of Latimeria chalumnae, providing new insights into its arrested differentiation in an air-breathing complex, mainly represented by the absence of pneumocytes and of compartmentalization in the latest ontogenetic stages. PMID:28405393

How to Perfuse: Concepts of Cerebral Protection during Arch Replacement

PubMed Central

Habertheuer, Andreas; Wiedemann, Dominik; Kocher, Alfred; Laufer, Guenther; Vallabhajosyula, Prashanth

2015-01-01

Arch surgery remains undoubtedly among the most technically and strategically challenging endeavors in cardiovascular surgery. Surgical interventions of thoracic aneurysms involving the aortic arch require complete circulatory arrest in deep hypothermia (DHCA) or elaborate cerebral perfusion strategies with varying degrees of hypothermia to achieve satisfactory protection of the brain from ischemic insults, that is, unilateral/bilateral antegrade cerebral perfusion (ACP) and retrograde cerebral perfusion (RCP). Despite sophisticated and increasingly individualized surgical approaches for complex aortic pathologies, there remains a lack of consensus regarding the optimal method of cerebral protection and circulatory management during the time of arch exclusion. Many recent studies argue in favor of ACP with various degrees of hypothermic arrest during arch reconstruction and its advantages have been widely demonstrated. In fact ACP with more moderate degrees of hypothermia represents a paradigm shift in the cardiac surgery community and is widely adopted as an emergent strategy; however, many centers continue to report good results using other perfusion strategies. Amidst this important discussion we review currently available surgical strategies of cerebral protection management and compare the results of recent European multicenter and single-center data. PMID:26713319

Microfluidic perfusion culture.

PubMed

Hattori, Koji; Sugiura, Shinji; Kanamori, Toshiyuki

2014-01-01

Microfluidic perfusion culture is a novel technique to culture animal cells in a small-scale microchamber with medium perfusion. Polydimethylsiloxane (PDMS) is the most popular material to fabricate a microfluidic perfusion culture chip. Photolithography and replica molding techniques are generally used for fabrication of a microfluidic perfusion culture chip. Pressure-driven perfusion culture system is convenient technique to carry out the perfusion culture of animal cells in a microfluidic device. Here, we describe a general theory on microfluid network design, microfabrication technique, and experimental technique for pressure-driven perfusion culture in an 8 × 8 microchamber array on a glass slide-sized microchip made out of PDMS.

Variation in Perfusion Strategies for Neonatal and Infant Aortic Arch Repair: Contemporary Practice in the STS Congenital Heart Surgery Database.

PubMed

Meyer, David B; Jacobs, Jeffrey P; Hill, Kevin; Wallace, Amelia S; Bateson, Brian; Jacobs, Marshall L

2016-09-01

Regional cerebral perfusion (RCP) is used as an adjunct or alternative to deep hypothermic circulatory arrest (DHCA) for neonates and infants undergoing aortic arch repair. Clinical studies have not demonstrated clear superiority of either strategy, and multicenter data regarding current use of these strategies are lacking. We sought to describe the variability in contemporary practice patterns for use of these techniques. The Society of Thoracic Surgeons Congenital Heart Surgery Database (2010-2013) was queried to identify neonates and infants whose index operation involved aortic arch repair with cardiopulmonary bypass. Perfusion strategy was classified as isolated DHCA, RCP (with less than or equal to ten minutes of DHCA), or mixed (RCP with more than ten minutes of DHCA). Data were analyzed for the entire cohort and stratified by operation subgroups. Overall, 4,523 patients (105 centers) were identified; median age seven days (interquartile range: 5.0-13.0). The most prevalent perfusion strategy was RCP (43%). Deep hypothermic circulatory arrest and mixed perfusion accounted for 32% and 16% of cases, respectively. In all, 59% of operations involved some period of RCP. Regional cerebral perfusion was the most prevalent perfusion strategy for each operation subgroup. Neither age nor weight was associated with perfusion strategy, but reoperations were less likely to use RCP (31% vs 45%, P < .001). The combined duration of RCP and DHCA in the RCP group was longer than the DHCA time in the DHCA group (45 vs 36 minutes, P < .001). There is considerable variability in practice regarding perfusion strategies for arch repair in neonates and infants. In contemporary practice, RCP is the most prevalent perfusion strategy for these procedures. Use of DHCA is also common. Further investigation is warranted to ascertain possible relative merits of the various perfusion techniques. © The Author(s) 2016.

Induction of Inducible Nitric Oxide Synthase by Lipopolysaccharide and the Influences of Cell Volume Changes, Stress Hormones and Oxidative Stress on Nitric Oxide Efflux from the Perfused Liver of Air-Breathing Catfish, Heteropneustes fossilis

PubMed Central

Choudhury, Mahua G.; Saha, Nirmalendu

2016-01-01

The air-breathing singhi catfish (Heteropneustes fossilis) is frequently being challenged by bacterial contaminants, and different environmental insults like osmotic, hyper-ammonia, dehydration and oxidative stresses in its natural habitats throughout the year. The main objectives of the present investigation were to determine (a) the possible induction of inducible nitric oxide synthase (iNOS) gene with enhanced production of nitric oxide (NO) by intra-peritoneal injection of lipopolysaccharide (LPS) (a bacterial endotoxin), and (b) to determine the effects of hepatic cell volume changes due to anisotonicity or by infusion of certain metabolites, stress hormones and by induction of oxidative stress on production of NO from the iNOS-induced perfused liver of singhi catfish. Intra-peritoneal injection of LPS led to induction of iNOS gene and localized tissue specific expression of iNOS enzyme with more production and accumulation of NO in different tissues of singhi catfish. Further, changes of hydration status/cell volume, caused either by anisotonicity or by infusion of certain metabolites such as glutamine plus glycine and adenosine, affected the NO production from the perfused liver of iNOS-induced singhi catfish. In general, increase of hydration status/cell swelling due to hypotonicity caused decrease, and decrease of hydration status/cell shrinkage due to hypertonicity caused increase of NO efflux from the perfused liver, thus suggesting that changes in hydration status/cell volume of hepatic cells serve as a potent modulator for regulating the NO production. Significant increase of NO efflux from the perfused liver was also observed while infusing the liver with stress hormones like epinephrine and norepinephrine, accompanied with decrease of hydration status/cell volume of hepatic cells. Further, oxidative stress, caused due to infusion of t-butyl hydroperoxide and hydrogen peroxide separately, in the perfused liver of singhi catfish, resulted in

Induction of Inducible Nitric Oxide Synthase by Lipopolysaccharide and the Influences of Cell Volume Changes, Stress Hormones and Oxidative Stress on Nitric Oxide Efflux from the Perfused Liver of Air-Breathing Catfish, Heteropneustes fossilis.

PubMed

Choudhury, Mahua G; Saha, Nirmalendu

2016-01-01

The air-breathing singhi catfish (Heteropneustes fossilis) is frequently being challenged by bacterial contaminants, and different environmental insults like osmotic, hyper-ammonia, dehydration and oxidative stresses in its natural habitats throughout the year. The main objectives of the present investigation were to determine (a) the possible induction of inducible nitric oxide synthase (iNOS) gene with enhanced production of nitric oxide (NO) by intra-peritoneal injection of lipopolysaccharide (LPS) (a bacterial endotoxin), and (b) to determine the effects of hepatic cell volume changes due to anisotonicity or by infusion of certain metabolites, stress hormones and by induction of oxidative stress on production of NO from the iNOS-induced perfused liver of singhi catfish. Intra-peritoneal injection of LPS led to induction of iNOS gene and localized tissue specific expression of iNOS enzyme with more production and accumulation of NO in different tissues of singhi catfish. Further, changes of hydration status/cell volume, caused either by anisotonicity or by infusion of certain metabolites such as glutamine plus glycine and adenosine, affected the NO production from the perfused liver of iNOS-induced singhi catfish. In general, increase of hydration status/cell swelling due to hypotonicity caused decrease, and decrease of hydration status/cell shrinkage due to hypertonicity caused increase of NO efflux from the perfused liver, thus suggesting that changes in hydration status/cell volume of hepatic cells serve as a potent modulator for regulating the NO production. Significant increase of NO efflux from the perfused liver was also observed while infusing the liver with stress hormones like epinephrine and norepinephrine, accompanied with decrease of hydration status/cell volume of hepatic cells. Further, oxidative stress, caused due to infusion of t-butyl hydroperoxide and hydrogen peroxide separately, in the perfused liver of singhi catfish, resulted in

Laws of physics help explain capillary non-perfusion in diabetic retinopathy.

PubMed

Stefánsson, E; Chan, Y K; Bek, T; Hardarson, S H; Wong, D; Wilson, D I

2018-02-01

The purpose is to use laws of physics to elucidate the mechanisms behind capillary non-perfusion in diabetic retinopathy. In diabetic retinopathy, loss of pericytes weakens capillary walls and the vessel dilates. A dilated capillary has reduced resistance to flow, therefore increased flow in that vessel and decreased in adjoining capillaries. A preferential shunt vessel is thus formed from the dilated capillary and the adjacent capillaries become non-perfused. We apply the laws of Laplace and Hagen-Poiseuille to better understand the phenomena that lead to capillary non-perfusion. These laws of physics can give a foundation for physical or mathematical models to further elucidate this field of study. The law of Laplace predicts that a weaker vessel wall will dilate, assuming constant transmural pressure. The Hagen-Poiseuille equation for flow and the Ostwald-de Waele relationship for viscosity predict that a dilated vessel will receive a higher portion of the fluid flow than the adjoining capillaries. Viscosity will decrease in the dilated vessel, furthering the imbalance and resulting in a patch of non-perfused capillaries next to the dilated 'preferential' shunt vessel. Physical principles support or inspire novel hypotheses to explain poorly understood phenomena in ophthalmology. This thesis of pericyte death and capillary remodelling, which was first proposed by Cogan and Kuwabara, already agrees with histological and angiographical observations in diabetic retinopathy. We have shown that it is also supported by classical laws of physics.

SU-E-T-605: RapidArc Combined with DIBH Technique for Thoracic Esophageal Carcinoma: The Potential Value of Target Immobilization and Reduced Lung Density in Dose Escalation.

PubMed

Yin, Y; Liu, T; Zhai, D

2012-06-01

To compare the dosimetric benefits of Rapidarc (RA) combined with deep inspiration breath-hold (DIBH) with those of other standard techniques, including free breathing (FB) during fixed-field intensity modulated radiation therapy (IMRT) and dual arc RA, in the treatment of patients with thoracic esophageal carcinoma (EC). Ten patients with EC underwent computed tomography (CT) scans under 2 respiration conditions: free-breathing (FB) and DIBH. These scans were used to generate 3-dimensional conformal treatment plans. For breath-hold scans, the patients were brought to reproducible respiration levels using active breathing control (ABC) maneuvers. Planning target volumes (PTVs) for FB plans included a 0.5 cm margin for setup plus a 1 cm margin equal to the extent of tumor motion for respiration. PTVs for DIBH plans included a 0.5 cm margin for setup error and a 0.5 cm margin for residual uncertainty in tumor position. Using a dose level of 60 Gy to the PTV, three treatment plans were generated: IMRT-FB, RA-FB and RA-ABC, and the target and normal tissue volumes were compared, as were the dosimetry parameters. On average, the DIBH technique resulted in increased lung volumes compared with FB techniques. There was no significant differences in gross tumor volume between the two breathing states (p > 0.05); but PTV and heart volume were larger for FB than for DIBH (p < 0.05). The overall CI and HI for the RA-ABC plan was slightly inferior to those of the IMRT- FB and RA-FB plans (p < 0.05 each). With DIBH, the heart was partly out of the beam portals and the average mean heart dose was reduced. Compared with conventional FB, RA combined with DIBH significantly reduced cardiac and pulmonary doses without compromising the target coverage and may reduce treatment toxicity, enabling dose escalation in future prospective studies of patients with EC. © 2012 American Association of Physicists in Medicine.

[The proliferative characteristics of cells in culture during perfusion of the medium].

PubMed

Akatov, V S; Lavrovskaia, V P; Lezhnev, E I

1991-01-01

The proliferation of Chinese hamster fibroblasts (CHF) and NIH 3T3 cells was studied at different flow rates immediately above the cells. It is shown that there is a limiting density of saturation of the perfused culture that accounts for 1.7 x 10(6) - 2.0 x 10(6) cells/cm2 for NIH 3T3 cells, and for 6 x 10(6) - 7 x 10(6) cells/cm2 for CHF. The growth curves and the distribution of cells with respect to the phases of the cell cycle during cultivation with and without perfusion are presented. Based on the results obtained it is assumed that the limit of saturation density of perfused CHF culture is due to the mass transfer of the growth-inhibiting metabolites inside the multilayer structures. The assumption seems to hold true for NIH 3T3 cells, too, even though the multilayer character of growth of this culture is less pronounced than in CHF.

SU-F-J-123: CT-Based Determination of DIBH Variability and Its Dosimetric Impact On Post-Mastectomy Plus Regional Nodal Radiation Therapy

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

Malin, M; Kang, H; Tatebe, K

Purpose: Breast cancer radiotherapy delivered using voluntary deep inspiration breath-hold (DIBH) requires reproducible breath holds, particularly when matching supraclavicular fields to tangential fields. We studied the impact of variation in DIBHs on CTV and OAR dose metrics by comparing the dose distribution computed on two DIBH CT scans taken at the time of simulation. Methods: Ten patients receiving 50Gy in 25 fractions to the left chestwall and regional lymph nodes were studied. Two simulation CT scans were taken during separate DIBHs along with a free-breathing (FB) scan. The treatment was planned using one DIBH CT. The dose was recomputed onmore » the other two scans using adaptive planning (Pinnacle 9.10) in which the scans are registered using a cross-correlation algorithm. The chestwall, lymph nodes and OARs were contoured on the scans following the RTOG consensus guidelines. The overall translational and rotational variation between the DIBH scans was used to estimate positional variation between breath-holds. Dose metrics between plans were compared using paired t-tests (p < 0.05) and means and standard deviations were reported. Results: The registration parameters were sub-millimeter and sub-degree. Although DIBH significantly reduced mean heart dose by 2.4Gy compared to FB (p < 0.01), no significant changes in dose were observed for targets or OARs between the two DIBH scans. Nodal coverage as assessed by V90% was 90%±8% and 89%±8% for supraclavicular and 99%±2% and 97%±22% for IM nodes. Though a significant decrease (10.5%±12.4%) in lung volume in the second DIBH CT was observed, the lung V20Gy was unchanged (14±2% and 14±3%) between the two DIBH scans. Conclusion: While the lung volume often varied between DIBHs, the CTV and OAR dose metrics were largely unchanged. This indicates that manual DIBH has the potential to provide consistent dose delivery to the chestwall and regional nodes targets when using matched fields.« less

Humidification performance of humidifying devices for tracheostomized patients with spontaneous breathing: a bench study.

PubMed

Chikata, Yusuke; Oto, Jun; Onodera, Mutsuo; Nishimura, Masaji

2013-09-01

Heat and moisture exchangers (HMEs) are commonly used for humidifying respiratory gases administered to mechanically ventilated patients. While they are also applied to tracheostomized patients with spontaneous breathing, their performance in this role has not yet been clarified. We carried out a bench study to investigate the effects of spontaneous breathing parameters and oxygen flow on the humidification performance of 11 HMEs. We evaluated the humidification provided by 11 HMEs for tracheostomized patients, and also by a system delivering high-flow CPAP, and an oxygen mask with nebulizer heater. Spontaneous breathing was simulated with a mechanical ventilator, lung model, and servo-controlled heated humidifier at tidal volumes of 300, 500, and 700 mL, and breathing frequencies of 10 and 20 breaths/min. Expired gas was warmed to 37°C. The high-flow CPAP system was set to deliver 15, 30, and 45 L/min. With the 8 HMEs that were equipped with ports to deliver oxygen, and with the high-flow CPAP system, measurements were taken when delivering 0 and 3 L/min of dry oxygen. After stabilization we measured the absolute humidity (AH) of inspired gas with a hygrometer. AH differed among HMEs applied to tracheostomized patients with spontaneous breathing. For all the HMEs, as tidal volume increased, AH decreased. At 20 breaths/min, AH was higher than at 10 breaths/min. For all the HMEs, when oxygen was delivered, AH decreased to below 30 mg/L. With an oxygen mask and high-flow CPAP, at all settings, AH exceeded 30 mg/L. None of the HMEs provided adequate humidification when supplemental oxygen was added. In the ICU, caution is required when applying HME to tracheostomized patients with spontaneous breathing, especially when supplemental oxygen is required.

Non-invasive monitoring of muscle blood perfusion by photoplethysmography: evaluation of a new application.

PubMed

Sandberg, M; Zhang, Q; Styf, J; Gerdle, B; Lindberg, L-G

2005-04-01

To evaluate a specially developed photoplethysmographic (PPG) technique, using green and near-infrared light sources, for simultaneous non-invasive monitoring of skin and muscle perfusion. Evaluation was based on assessments of changes in blood perfusion to various provocations, such as post-exercise hyperaemia and hyperaemia following the application of liniment. The deep penetrating feature of PPG was investigated by measurement of optical radiation inside the muscle. Simultaneous measurements using ultrasound Doppler and the new PPG application were performed to elucidate differences between the two methods. Specific problems related to the influence of skin temperature on blood flow were highlightened, as well. Following static and dynamic contractions an immediate increase in muscle perfusion was shown, without increase in skin perfusion. Liniment application to the skin induced a rapid increase in skin perfusion, but not in muscle. Both similarities and differences in blood flow measured by Ultrasound Doppler and PPG were demonstrated. The radiant power measured inside the muscle, by use of an optical fibre, showed that the near-infrared light penetrates down to the vascular depth inside the muscle. The results of this study indicate the potentiality of the method for non-invasive measurement of local muscle perfusion, although some considerations still have to be accounted for, such as influence of temperature on blood perfusion.

Free-breathing volumetric fat/water separation by combining radial sampling, compressed sensing, and parallel imaging.

PubMed

Benkert, Thomas; Feng, Li; Sodickson, Daniel K; Chandarana, Hersh; Block, Kai Tobias

2017-08-01

Conventional fat/water separation techniques require that patients hold breath during abdominal acquisitions, which often fails and limits the achievable spatial resolution and anatomic coverage. This work presents a novel approach for free-breathing volumetric fat/water separation. Multiecho data are acquired using a motion-robust radial stack-of-stars three-dimensional GRE sequence with bipolar readout. To obtain fat/water maps, a model-based reconstruction is used that accounts for the off-resonant blurring of fat and integrates both compressed sensing and parallel imaging. The approach additionally enables generation of respiration-resolved fat/water maps by detecting motion from k-space data and reconstructing different respiration states. Furthermore, an extension is described for dynamic contrast-enhanced fat-water-separated measurements. Uniform and robust fat/water separation is demonstrated in several clinical applications, including free-breathing noncontrast abdominal examination of adults and a pediatric subject with both motion-averaged and motion-resolved reconstructions, as well as in a noncontrast breast exam. Furthermore, dynamic contrast-enhanced fat/water imaging with high temporal resolution is demonstrated in the abdomen and breast. The described framework provides a viable approach for motion-robust fat/water separation and promises particular value for clinical applications that are currently limited by the breath-holding capacity or cooperation of patients. Magn Reson Med 78:565-576, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Lesional perfusion abnormalities in Leigh disease demonstrated by arterial spin labeling correlate with disease activity.

PubMed

Whitehead, Matthew T; Lee, Bonmyong; Gropman, Andrea

2016-08-01

Leigh disease is a metabolic disorder of the mitochondrial respiratory chain culminating in symmetrical necrotizing lesions in the deep gray nuclei or brainstem. Apart from classic gliotic/necrotic lesions, small-vessel proliferation is also characteristic on histopathology. We have observed lesional hyperperfusion on arterial spin-labeling (ASL) sequence in children with Leigh disease. In this cross-sectional analysis, we evaluated lesional ASL perfusion characteristics in children with Leigh syndrome. We searched the imaging database from an academic children's hospital for "arterial spin labeling, perfusion, necrosis, lactate, and Leigh" to build a cohort of children for retrospective analysis. We reviewed each child's medical record to confirm a diagnosis of Leigh disease, excluding exams with artifact, technical limitations, and without ASL images. We evaluated the degree and extent of cerebral blood flow and relationship to brain lesions. Images were compared to normal exams from an aged-matche cohort. The database search yielded 45 exams; 30 were excluded. We evaluated 15 exams from 8 children with Leigh disease and 15 age-matched normal exams. In general, Leigh brain perfusion ranged from hyperintense (n=10) to hypointense (n=5). Necrotic lesions appeared hypointense/hypoperfused. Active lesions with associated restricted diffusion demonstrated hyperperfusion. ASL perfusion patterns differed significantly from those on age-matched normal studies (P=<.0001). Disease activity positively correlated with cerebral deep gray nuclei hyperperfusion (P=0.0037) and lesion grade (P=0.0256). Children with Leigh disease have abnormal perfusion of brain lesions. Hyperperfusion can be found in active brain lesions, possibly associated with small-vessel proliferation characteristic of the disease.

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

Breath-collection device for delayed breath-alcohol analysis

DOT National Transportation Integrated Search

1980-12-01

The report includes the details of a study to develop, evaluate, and validate a breath collection device (BCD) for delayed breath-alcohol analysis. Primary applications of the BCD include collection of breath-alcohol samples for field surveys or for ...

Classifying geometric variability by dominant eigenmodes of deformation in regressing tumours during active breath-hold lung cancer radiotherapy

NASA Astrophysics Data System (ADS)

Badawi, Ahmed M.; Weiss, Elisabeth; Sleeman, William C., IV; Hugo, Geoffrey D.

2012-01-01

The purpose of this study is to develop and evaluate a lung tumour interfraction geometric variability classification scheme as a means to guide adaptive radiotherapy and improve measurement of treatment response. Principal component analysis (PCA) was used to generate statistical shape models of the gross tumour volume (GTV) for 12 patients with weekly breath hold CT scans. Each eigenmode of the PCA model was classified as ‘trending’ or ‘non-trending’ depending on whether its contribution to the overall GTV variability included a time trend over the treatment course. Trending eigenmodes were used to reconstruct the original semi-automatically delineated GTVs into a reduced model containing only time trends. Reduced models were compared to the original GTVs by analyzing the reconstruction error in the GTV and position. Both retrospective (all weekly images) and prospective (only the first four weekly images) were evaluated. The average volume difference from the original GTV was 4.3% ± 2.4% for the trending model. The positional variability of the GTV over the treatment course, as measured by the standard deviation of the GTV centroid, was 1.9 ± 1.4 mm for the original GTVs, which was reduced to 1.2 ± 0.6 mm for the trending-only model. In 3/13 cases, the dominant eigenmode changed class between the prospective and retrospective models. The trending-only model preserved GTV and shape relative to the original GTVs, while reducing spurious positional variability. The classification scheme appears feasible for separating types of geometric variability by time trend.

Inside anesthesia breathing circuits: time to reach a set sevoflurane concentration in toddlers and newborns: simulation using a test lung.

PubMed

Kern, Delphine; Larcher, Claire; Basset, Bertrand; Alacoque, Xavier; Fesseau, Rose; Samii, Kamran; Minville, Vincent; Fourcade, Olivier

2012-08-01

We measured the time it takes to reach the desired inspired anesthetic concentration using the Primus (Drägerwerk, AG, Lübeck, Germany) and the Avance (GE Datex-Ohmeda, Munich, Germany) anesthesia machines with toddler and newborn ventilation settings. The time to reach 95% of inspired target sevoflurane concentration was measured during wash-in from 0 to 6 vol% sevoflurane and during wash-out from 6 to 0 vol% with fresh gas flows equal to 1 and 2 times the minute ventilation. The Avance was faster than the Primus (65 seconds [95% confidence interval (CI): 55 to 78] vs 310 seconds [95% CI: 261 to 359]) at 1.5 L/min fresh gas flow, tidal volume of 50 mL, and 30 breaths/min. Times were shorter by the same magnitude at higher fresh gas flows and higher minute ventilation rates. The effect of doubling fresh gas flow was variable and less than expected. The Primus is slower during newborn than toddler ventilation, whereas the Avance's response time was the same for newborn and toddler ventilation. Our data confirm that the time to reach the target-inspired anesthetic concentration depends on breathing circuit volume, fresh gas flow, and minute ventilation.

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.

PERIODIC AIR-BREATHING BEHAVIOUR IN A PRIMITIVE FISH REVEALED BY SPECTRAL ANALYSIS

PubMed

Hedrick; Katz; Jones

1994-12-01

The ventilatory patterns of air-breathing fish are commonly described as 'arrhythmic' or 'irregular' because the variable periods of breath-holding are punctuated by seemingly unpredictable air-breathing events (see Shelton et al. 1986). This apparent arrhythmicity contrasts with the perceived periodism or regularity in the gill ventilation patterns of some fish and with lung ventilation in birds and mammals. In this sense, periodism refers to behaviour that occurs with a definite, recurring interval (Bendat and Piersol, 1986). The characterisation of aerial ventilation patterns in fish as 'aperiodic' has been generally accepted on the basis of qualitative examination and it remains to be validated with rigorous testing. The bowfin, Amia calva (L.), is a primitive air-breathing fish that makes intermittent excursions to the air­water interface to gulp air, which is transferred to its well-vascularized gas bladder. Its phylogenetic position as the only extant member of the sister lineage of modern teleosts affords a unique opportunity to examine the evolution of aerial ventilation and provides a model for the examination of ventilatory patterns in primitive fishes. To establish whether Amia calva exhibit a particular pattern of air-breathing, we examined time series records of aerial ventilations from undisturbed fish over long periods (8 h). These records were the same as those used to calculate average ventilation intervals under a variety of experimental conditions (Hedrick and Jones, 1993). Their study also reported the occurrence of two distinct breath types. Type I breaths were characterised by an exhalation followed by an inhalation, whereas type II breaths were characterised by inhalation only. It was also hypothesized that the type I breaths were employed to meet oxygen demands, whereas the type II breaths were used to regulate gas bladder volume. However, they did not investigate the potential presence of a periodic ventilatory pattern. We now report

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.

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.

Ventilation/perfusion ratios measured by multiple inert gas elimination during experimental cardiopulmonary resuscitation.

PubMed

Hartmann, E K; Duenges, B; Boehme, S; Szczyrba, M; Liu, T; Klein, K U; Baumgardner, J E; Markstaller, K; David, M

2014-09-01

During cardiopulmonary resuscitation (CPR) the ventilation/perfusion distribution (VA /Q) within the lung is difficult to assess. This experimental study examines the capability of multiple inert gas elimination (MIGET) to determine VA /Q under CPR conditions in a pig model. Twenty-one anaesthetised pigs were randomised to three fractions of inspired oxygen (1.0, 0.7 or 0.21). VA/ Q by micropore membrane inlet mass spectrometry-derived MIGET was determined at baseline and during CPR following induction of ventricular fibrillation. Haemodynamics, blood gases, ventilation distribution by electrical impedance tomography and return of spontaneous circulation were assessed. Intergroup differences were analysed by non-parametric testing. MIGET measurements were feasible in all animals with an excellent correlation of measured and predicted arterial oxygen partial pressure (R(2)  = 0.96, n = 21 for baseline; R(2)  = 0.82, n = 21 for CPR). CPR induces a significant shift from normal VA /Q ratios to the high VA /Q range. Electrical impedance tomography indicates a dorsal to ventral shift of the ventilation distribution. Diverging pulmonary shunt fractions induced by the three inspired oxygen levels considerably increased during CPR and were traceable by MIGET, while 100% oxygen most negatively influenced the VA /Q. Return of spontaneous circulation were achieved in 52% of the animals. VA /Q assessment by MIGET is feasible during CPR and provides a novel tool for experimental purposes. Changes in VA /Q caused by different oxygen fractions are traceable during CPR. Beyond pulmonary perfusion deficits, these data imply an influence of the inspired oxygen level on VA /Q. Higher oxygen levels significantly increase shunt fractions and impair the normal VA /Q ratio. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Quantitative lung perfusion evaluation using Fourier decomposition perfusion MRI.

PubMed

Kjørstad, Åsmund; Corteville, Dominique M R; Fischer, Andre; Henzler, Thomas; Schmid-Bindert, Gerald; Zöllner, Frank G; Schad, Lothar R

2014-08-01

To quantitatively evaluate lung perfusion using Fourier decomposition perfusion MRI. The Fourier decomposition (FD) method is a noninvasive method for assessing ventilation- and perfusion-related information in the lungs, where the perfusion maps in particular have shown promise for clinical use. However, the perfusion maps are nonquantitative and dimensionless, making follow-ups and direct comparisons between patients difficult. We present an approach to obtain physically meaningful and quantifiable perfusion maps using the FD method. The standard FD perfusion images are quantified by comparing the partially blood-filled pixels in the lung parenchyma with the fully blood-filled pixels in the aorta. The percentage of blood in a pixel is then combined with the temporal information, yielding quantitative blood flow values. The values of 10 healthy volunteers are compared with SEEPAGE measurements which have shown high consistency with dynamic contrast enhanced-MRI. All pulmonary blood flow (PBF) values are within the expected range. The two methods are in good agreement (mean difference = 0.2 mL/min/100 mL, mean absolute difference = 11 mL/min/100 mL, mean PBF-FD = 150 mL/min/100 mL, mean PBF-SEEPAGE = 151 mL/min/100 mL). The Bland-Altman plot shows a good spread of values, indicating no systematic bias between the methods. Quantitative lung perfusion can be obtained using the Fourier Decomposition method combined with a small amount of postprocessing. Copyright © 2013 Wiley Periodicals, Inc.

How to breathe when you are short of breath

MedlinePlus

... pursed lip breathing; Hypoxia - pursed lip breathing; Chronic respiratory failure - pursed lip breathing ... et al, eds. Murray and Nadel's Textbook of Respiratory Medicine . 6th ed. Philadelphia, PA: Elsevier Saunders; 2016: ...

Renal perfusion scintiscan

MedlinePlus

... Radionuclide renal perfusion scan; Perfusion scintiscan - renal; Scintiscan - renal perfusion Images Kidney anatomy Kidney - blood and urine flow Intravenous pyelogram References Rottenberg G, Andi AC. Renal ...

High-performance mussel-inspired adhesives of reduced complexity.

PubMed

Ahn, B Kollbe; Das, Saurabh; Linstadt, Roscoe; Kaufman, Yair; Martinez-Rodriguez, Nadine R; Mirshafian, Razieh; Kesselman, Ellina; Talmon, Yeshayahu; Lipshutz, Bruce H; Israelachvili, Jacob N; Waite, J Herbert

2015-10-19

Despite the recent progress in and demand for wet adhesives, practical underwater adhesion remains limited or non-existent for diverse applications. Translation of mussel-inspired wet adhesion typically entails catechol functionalization of polymers and/or polyelectrolytes, and solution processing of many complex components and steps that require optimization and stabilization. Here we reduced the complexity of a wet adhesive primer to synthetic low-molecular-weight catecholic zwitterionic surfactants that show very strong adhesion (∼50 mJ m(-2)) and retain the ability to coacervate. This catecholic zwitterion adheres to diverse surfaces and self-assembles into a molecularly smooth, thin (<4 nm) and strong glue layer. The catecholic zwitterion holds particular promise as an adhesive for nanofabrication. This study significantly simplifies bio-inspired themes for wet adhesion by combining catechol with hydrophobic and electrostatic functional groups in a small molecule.

SU-D-18A-06: Variation of Controlled Breath Hold From CT Simulation to Treatment and Its Dosimetric Impact for Left-Sided Breast Radiotherapy with a Real-Time Optical Tracking System

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

Mittauer, K; Deraniyagala, R; Li, J

2014-06-01

Purpose: Different breath-hold (BH) maneuvers (abdominal breathing vs. chest breathing) during CT simulation and treatment can lead to chest wall positional variation. The purpose of this study is to quantify the variation of active breathing control (ABC)-assisted BH and estimate its dosimetric impact for left-sided whole-breast radiotherapy with a real-time optical tracking system (OTS). Methods: Seven breast cancer patients were included. An in-house OTS tracked an infrared (IR) marker affixed over the xiphoid process of the patient at CT simulation and throughout the treatment course to measure BH variations. Correlation between the IR marker and the breast was studied formore » dosimetric purposes. The positional variations of 860 BHs were retrospectively incorporated into treatment plans to assess their dosimetric impact on breast and cardiac organs (heart and left anterior descending artery [LAD]). Results: The mean intrafraction variations were 2.8 mm, 2.7 mm, and 1.6 mm in the anteroposterior (AP), craniocaudal (CC), and mediolateral (ML) directions, respectively. Mean stability in any direction was within 1.5 mm. A general trend of BH undershoot at treatment relative to CT simulation was observed with an average of 4.4 mm, 3.6 mm, and 0.1 mm in the AP, CC, and ML directions, respectively. Undershoot up to 12.6 mm was observed for individual patients. The difference between the planned and delivered dose to breast targets was negligible. The average planned/delivered mean heart doses, mean LAD doses, and max LAD doses were 1.4/2.1, 7.4/15.7, and 18.6/31.0 Gy, respectively. Conclusion: Systematic undershoot was observed in ABC-assisted BHs from CT simulation to treatment. Its dosimetric impact on breast coverage was minimized with image guidance, but the benefits of cardiac organ sparing were degraded. A real-time tracking system can be used in junction with the ABC device to improve BH reproducibility.« less

Comparison of spectroscopically measured finger and forearm tissue ethanol concentration to blood and breath ethanol measurements

NASA Astrophysics Data System (ADS)

Ridder, Trent D.; Hull, Edward L.; Ver Steeg, Benjamin J.; Laaksonen, Bentley D.

2011-02-01

Previous works investigated a spectroscopic technique that offered a promising alternative to blood and breath assays for determining in vivo alcohol concentration. Although these prior works measured the dorsal forearm, we report the results of a 26-subject clinical study designed to evaluate the spectroscopic technique at a finger measurement site through comparison to contemporaneous forearm spectroscopic, venous blood, and breath measurements. Through both Monte Carlo simulation and experimental data, it is shown that tissue optical probe design has a substantial impact on the effective path-length of photons through the skin and the signal-to-noise ratio of the spectroscopic measurements. Comparison of the breath, blood, and tissue assays demonstrated significant differences in alcohol concentration that are attributable to both assay accuracy and alcohol pharmacokinetics. Similar to past works, a first order kinetic model is used to estimate the fraction of concentration variance explained by alcohol pharmacokinetics (72.6-86.7%). A significant outcome of this work was significantly improved pharmacokinetic agreement with breath (arterial) alcohol of the finger measurement (mean kArt-Fin = 0.111 min-1) relative to the forearm measurement (mean kArt-For = 0.019 min-1) that is likely due to the increased blood perfusion of the finger.

Assessment of multislice CT to quantify pulmonary emphysema function and physiology in a rat model

NASA Astrophysics Data System (ADS)

Cao, Minsong; Stantz, Keith M.; Liang, Yun; Krishnamurthi, Ganapathy; Presson, Robert G., Jr.

2005-04-01

Purpose: The purpose of this study is to evaluate multi-slice computed tomography technology to quantify functional and physiologic changes in rats with pulmonary emphysema. Method: Seven rats were scanned using a 16-slice CT (Philips MX8000 IDT) before and after artificial inducement of emphysema. Functional parameters i.e. lung volumes were measured by non-contrast spiral scan during forced breath-hold at inspiration and expiration followed by image segmentation based on attenuation threshold. Dynamic CT imaging was performed immediately following the contrast injection to estimate physiology changes. Pulmonary perfusion, fractional blood volume, and mean transit times (MTTs) were estimated by fitting the time-density curves of contrast material using a compartmental model. Results: The preliminary results indicated that the lung volumes of emphysema rats increased by 3.52+/-1.70mL (p<0.002) at expiration and 4.77+/-3.34mL (p<0.03) at inspiration. The mean lung densities of emphysema rats decreased by 91.76+/-68.11HU (p<0.01) at expiration and low attenuation areas increased by 5.21+/-3.88% (p<0.04) at inspiration compared with normal rats. The perfusion for normal and emphysema rats were 0.25+/-0.04ml/s/ml and 0.32+/-0.09ml/s/ml respectively. The fractional blood volumes for normal and emphysema rats were 0.21+/-0.04 and 0.15+/-0.02. There was a trend toward faster MTTs for emphysema rats (0.42+/-0.08s) than normal rats (0.89+/-0.19s) with p<0.006, suggesting that blood flow crossing the capillaries increases as the capillary volume decreases and which may cause the red blood cells to leave the capillaries incompletely saturated with oxygen if the MTTs become too short. Conclusion: Quantitative measurement using CT of structural and functional changes in pulmonary emphysema appears promising for small animals.

Diffusion Tractography of the Entire Left Ventricle by Using Free-breathing Accelerated Simultaneous Multisection Imaging.

PubMed

Mekkaoui, Choukri; Reese, Timothy G; Jackowski, Marcel P; Cauley, Stephen F; Setsompop, Kawin; Bhat, Himanshu; Sosnovik, David E

2017-03-01

Purpose To develop a clinically feasible whole-heart free-breathing diffusion-tensor (DT) magnetic resonance (MR) imaging approach with an imaging time of approximately 15 minutes to enable three-dimensional (3D) tractography. Materials and Methods The study was compliant with HIPAA and the institutional review board and required written consent from the participants. DT imaging was performed in seven healthy volunteers and three patients with pulmonary hypertension by using a stimulated echo sequence. Twelve contiguous short-axis sections and six four-chamber sections that covered the entire left ventricle were acquired by using simultaneous multisection (SMS) excitation with a blipped-controlled aliasing in parallel imaging readout. Rate 2 and rate 3 SMS excitation was defined as two and three times accelerated in the section axis, respectively. Breath-hold and free-breathing images with and without SMS acceleration were acquired. Diffusion-encoding directions were acquired sequentially, spatiotemporally registered, and retrospectively selected by using an entropy-based approach. Myofiber helix angle, mean diffusivity, fractional anisotropy, and 3D tractograms were analyzed by using paired t tests and analysis of variance. Results No significant differences (P > .63) were seen between breath-hold rate 3 SMS and free-breathing rate 2 SMS excitation in transmural myofiber helix angle, mean diffusivity (mean ± standard deviation, [0.89 ± 0.09] × 10 -3 mm 2 /sec vs [0.9 ± 0.09] × 10 -3 mm 2 /sec), or fractional anisotropy (0.43 ± 0.05 vs 0.42 ± 0.06). Three-dimensional tractograms of the left ventricle with no SMS and rate 2 and rate 3 SMS excitation were qualitatively similar. Conclusion Free-breathing DT imaging of the entire human heart can be performed in approximately 15 minutes without section gaps by using SMS excitation with a blipped-controlled aliasing in parallel imaging readout, followed by spatiotemporal registration and entropy

Factors influencing the measurement of closing volume.

PubMed

Make, B; Lapp, N L

1975-06-01

The various factors influencing closing volume were studied by performing the single-breath N2 test on 9 healthy nonsmokers. Time of day, day of the week, and preceding volume history had no effect on either closing volume or alveolar plateau. Slow inspiratory flow resulted in larger ratio of closing volume to vital capacity, ratio of closing capacity to total lung capacity, and change in N2 concentration than fast inspiratory flow. Voluntary regulation of the expiratory flow resulted in smaller ratios of closing volume to vital capacity and closing capacity to total lung capacity than when flow was regulated by a resistance. Prolonged breath holding of the inspired O2 led to larger ratio of closing volume to vital capacity and ratio of closing capacity to total lung capacity. To obtain uniform, comparable closing volumes, it is suggested that the subject inspire slowly, control expiratory flow (preferably voluntarily), and not pause between inspiration and expiration.

A Voluntary Breath-Hold Treatment Technique for the Left Breast With Unfavorable Cardiac Anatomy Using Surface Imaging

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

Gierga, David P., E-mail: dgierga@partners.org; Harvard Medical School, Boston, Massachusetts; Turcotte, Julie C.

2012-12-01

Purpose: Breath-hold (BH) treatments can be used to reduce cardiac dose for patients with left-sided breast cancer and unfavorable cardiac anatomy. A surface imaging technique was developed for accurate patient setup and reproducible real-time BH positioning. Methods and Materials: Three-dimensional surface images were obtained for 20 patients. Surface imaging was used to correct the daily setup for each patient. Initial setup data were recorded for 443 fractions and were analyzed to assess random and systematic errors. Real time monitoring was used to verify surface placement during BH. The radiation beam was not turned on if the BH position difference wasmore » greater than 5 mm. Real-time surface data were analyzed for 2398 BHs and 363 treatment fractions. The mean and maximum differences were calculated. The percentage of BHs greater than tolerance was calculated. Results: The mean shifts for initial patient setup were 2.0 mm, 1.2 mm, and 0.3 mm in the vertical, longitudinal, and lateral directions, respectively. The mean 3-dimensional vector shift was 7.8 mm. Random and systematic errors were less than 4 mm. Real-time surface monitoring data indicated that 22% of the BHs were outside the 5-mm tolerance (range, 7%-41%), and there was a correlation with breast volume. The mean difference between the treated and reference BH positions was 2 mm in each direction. For out-of-tolerance BHs, the average difference in the BH position was 6.3 mm, and the average maximum difference was 8.8 mm. Conclusions: Daily real-time surface imaging ensures accurate and reproducible positioning for BH treatment of left-sided breast cancer patients with unfavorable cardiac anatomy.« less

Neuropeptides and nitric oxide synthase in the gill and the air-breathing organs of fishes.

PubMed

Zaccone, Giacomo; Mauceri, Angela; Fasulo, Salvatore

2006-05-01

Anatomical and histochemical studies have demonstrated that the bulk of autonomic neurotransmission in fish gill is attributed to cholinergic and adrenergic mechanisms (Nilsson. 1984. In: Hoar WS, Randall DJ, editors. Fish physiology, Vol. XA. Orlando: Academic Press. p 185-227; Donald. 1998. In: Evans DH, editor. The physiology of fishes, 2nd edition. Boca Raton: CRC Press. p 407-439). In many tissues, blockade of adrenergic and cholinergic transmission results in residual responses to nerve stimulation, which are termed NonAdrenergic, NonCholinergic (NANC). The discovery of nitric oxide (NO) has provided a basis for explaining many examples of NANC transmissions with accumulated physiological and pharmacological data indicating its function as a primary NANC transmitter. Little is known about the NANC neurotransmission, and studies on neuropeptides and NOS (Nitric Oxide Synthase) are very fragmentary in the gill and the air-breathing organs of fishes. Knowledge of the distribution of nerves and effects of perfusing agonists may help to understand the mechanisms of perfusion regulation in the gill (Olson. 2002. J Exp Zool 293:214-231). Air breathing as a mechanism for acquiring oxygen has evolved independently in several groups of fishes, necessitating modifications of the organs responsible for the exchange of gases. Aquatic hypoxia in freshwaters has been probably the more important selective force in the evolution of air breathing in vertebrates. Fishes respire with gills that are complex structures with many different effectors and potential control systems. Autonomic innervation of the gill has received considerable attention. An excellent review on branchial innervation includes Sundin and Nilsson's (2002. J Exp Zool 293:232-248) with an emphasis on the anatomy and basic functioning of afferent and efferent fibers of the branchial nerves. The chapters by Evans (2002. J Exp Zool 293:336-347) and Olson (2002) provide new challenges about a variety of

Air breathing and aquatic gas exchange during hypoxia in armoured catfish.

PubMed

Scott, Graham R; Matey, Victoria; Mendoza, Julie-Anne; Gilmour, Kathleen M; Perry, Steve F; Almeida-Val, Vera M F; Val, Adalberto L

2017-01-01

Air breathing in fish is commonly believed to have arisen as an adaptation to aquatic hypoxia. The effectiveness of air breathing for tissue O 2 supply depends on the ability to avoid O 2 loss as oxygenated blood from the air-breathing organ passes through the gills. Here, we evaluated whether the armoured catfish (Hypostomus aff. pyreneusi)-a facultative air breather-can avoid branchial O 2 loss while air breathing in aquatic hypoxia, and we measured various other respiratory and metabolic traits important for O 2 supply and utilization. Fish were instrumented with opercular catheters to measure the O 2 tension (PO 2 ) of expired water, and air breathing and aquatic respiration were measured during progressive stepwise hypoxia in the water. Armoured catfish exhibited relatively low rates of O 2 consumption and gill ventilation, and gill ventilation increased in hypoxia due primarily to increases in ventilatory stroke volume. Armoured catfish began air breathing at a water PO 2 of 2.5 kPa, and both air-breathing frequency and hypoxia tolerance (as reflected by PO 2 at loss of equilibrium, LOE) was greater in individuals with a larger body mass. Branchial O 2 loss, as reflected by higher PO 2 in expired than in inspired water, was observed in a minority (4/11) of individuals as water PO 2 approached that at LOE. Armoured catfish also exhibited a gill morphology characterized by short filaments bearing short fused lamellae, large interlamellar cell masses, low surface area, and a thick epithelium that increased water-to-blood diffusion distance. Armoured catfish had a relatively low blood-O 2 binding affinity when sampled in normoxia (P 50 of 3.1 kPa at pH 7.4), but were able to rapidly increase binding affinity during progressive hypoxia exposure (to a P 50 of 1.8 kPa). Armoured catfish also had low activities of several metabolic enzymes in white muscle, liver, and brain. Therefore, low rates of metabolism and gill ventilation, and a reduction in branchial gas

Hypoxic Pulmonary Vasoconstriction Does Not Explain All Regional Perfusion Redistribution in Asthma.

PubMed

Kelly, Vanessa J; Hibbert, Kathryn A; Kohli, Puja; Kone, Mamary; Greenblatt, Elliot E; Venegas, Jose G; Winkler, Tilo; Harris, R Scott

2017-10-01

Regional hypoventilation in bronchoconstricted patients with asthma is spatially associated with reduced perfusion, which is proposed to result from hypoxic pulmonary vasoconstriction (HPV). To determine the role of HPV in the regional perfusion redistribution in bronchoconstricted patients with asthma. Eight patients with asthma completed positron emission tomographic/computed tomographic lung imaging at baseline and after bronchoconstriction, breathing either room air or 80% oxygen (80% O 2 ) on separate days. Relative perfusion, specific ventilation (sV), and gas fraction (Fgas) in the 25% of the lung with the lowest specific ventilation (sV low ) and the remaining lung (sV high ) were quantified and compared. In the sV low region, bronchoconstriction caused a significant decrease in sV under both room air and 80% O 2 conditions (baseline vs. bronchoconstriction, mean ± SD, 1.02 ± 0.20 vs. 0.35 ± 0.19 and 1.03 ± 0.20 vs. 0.32 ± 0.16, respectively; P < 0.05). In the sV low region, relative perfusion decreased after bronchoconstriction under room air conditions and also, to a lesser degree, under 80% O 2 conditions (1.02 ± 0.19 vs. 0.72 ± 0.08 [P < 0.001] and 1.08 ± 0.19 vs. 0.91 ± 0.12 [P < 0.05], respectively). The Fgas increased after bronchoconstriction under room air conditions only (0.99 ± 0.04 vs. 1.00 ± 0.02; P < 0.05). The sV low subregion analysis indicated that some of the reduction in relative perfusion after bronchoconstriction under 80% O 2 conditions occurred as a result of the presence of regional hypoxia. However, relative perfusion was also significantly reduced in sV low subregions that were hyperoxic under 80% O 2 conditions. HPV is not the only mechanism that contributes to perfusion redistribution in bronchoconstricted patients with asthma, suggesting that another nonhypoxia mechanism also contributes. We propose that this nonhypoxia mechanism may be either direct

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

A decrease in nasal CO2 stimulates breathing in the tegu lizard.

PubMed

Coates, E L; Furilla, R A; Ballam, G O; Bartlett, D

1991-10-01

Tegu lizards decrease ventilatory frequency (f) when constant CO2, as low as 0.4%, is delivered to the nasal cavities. In contrast, CO2, as high as 6%, pulsed into the nasal cavities during the expiratory phase of the breathing cycle does not alter f. The purpose of the present study was to investigate further the effect of nasal CO2 pattern on f in tegu lizards. Specifically, we tested: (1) whether f was affected by CO2 delivered to the nasal cavities during the inspiratory phase of the breathing cycle, and (2) whether pulsed decreases in nasal CO2 from 4% to 2% and from 4% to 0% would remove the f inhibition caused by constant nasal CO2. Ventilation was measured using a pneumotachograph and pressure transducer in-line with an endotracheal T-tube inserted through the glottis. CO2 was delivered to the nasal cavities through small tubes inserted into the external nares. Ventilatory frequency was not significantly altered when 4% CO2 was pulsed into the nasal cavities during inspiration. Dropping the CO2 in the nasal cavities from 4% to 0% at either 15 cycles/min (0.25 Hz) or for one cycle stimulated breathing. There was no significant difference between the f response to a drop in CO2 from 4% to 0% and that to a drop in CO2 from 4% to 2%. The failure to link the phasic CO2 ventilatory response to a phase in the respiratory cycle indicates that the nasal CO2 receptors do not participate in the breath-by-breath regulation of breathing in these lizards. The observation that small decreases in nasal CO2 abolished the f inhibition caused by constant nasal CO2 provides further evidence for the ability of the nasal CO2 receptors to distinguish between pulsed and constant CO2.

Pressure breathing in fighter aircraft for G accelerations and loss of cabin pressurization at altitude--a brief review.

PubMed

Lauritzsen, Lars P; Pfitzner, John

2003-04-01

The purpose of this brief review is to outline the past and present use of pressure breathing, not by patients but by fighter pilots. Of the historical and recent references quoted, most are from aviation-medicine journals that are not often readily available to anesthesiologists. Pressure breathing at moderate levels of airway pressure gave World War II fighter pilots a tactical altitude advantage. With today's fast and highly maneuverable jet fighters, very much higher airway pressures of the order of 8.0 kPa (identical with 60 mmHg) are used. They are used in conjunction with a counterpressure thoracic vest and an anti-G suit for the abdomen and lower body. Pressurization is activated automatically in response to +Gz accelerations, and to a potentially catastrophic loss of cabin pressurization at altitude. During +Gz accelerations, pressure breathing has been shown to maintain cerebral perfusion by raising the systemic arterial pressure, so increasing the level of G-tolerance that is afforded by the use of anti-G suits and seat tilt-back angles alone. This leaves the pilot less reliant on rigorous, and potentially distracting, straining maneuvers. With loss of cabin pressurization at altitude, pressure breathing of 100% oxygen at high airway pressures enables the pilot's alveolar PO(2) to be maintained at a safe level during emergency descent. Introduced in military aviation, pressure breathing for G-tolerance and pressure breathing for altitude presented as concepts that may be of general physiological interest to many anesthesiologists.

Fourier-based linear systems description of free-breathing pulmonary magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Capaldi, D. P. I.; Svenningsen, S.; Cunningham, I. A.; Parraga, G.

2015-03-01

Fourier-decomposition of free-breathing pulmonary magnetic resonance imaging (FDMRI) was recently piloted as a way to provide rapid quantitative pulmonary maps of ventilation and perfusion without the use of exogenous contrast agents. This method exploits fast pulmonary MRI acquisition of free-breathing proton (1H) pulmonary images and non-rigid registration to compensate for changes in position and shape of the thorax associated with breathing. In this way, ventilation imaging using conventional MRI systems can be undertaken but there has been no systematic evaluation of fundamental image quality measurements based on linear systems theory. We investigated the performance of free-breathing pulmonary ventilation imaging using a Fourier-based linear system description of each operation required to generate FDMRI ventilation maps. Twelve subjects with chronic obstructive pulmonary disease (COPD) or bronchiectasis underwent pulmonary function tests and MRI. Non-rigid registration was used to co-register the temporal series of pulmonary images. Pulmonary voxel intensities were aligned along a time axis and discrete Fourier transforms were performed on the periodic signal intensity pattern to generate frequency spectra. We determined the signal-to-noise ratio (SNR) of the FDMRI ventilation maps using a conventional approach (SNRC) and using the Fourier-based description (SNRF). Mean SNR was 4.7 ± 1.3 for subjects with bronchiectasis and 3.4 ± 1.8, for COPD subjects (p>.05). SNRF was significantly different than SNRC (p<.01). SNRF was approximately 50% of SNRC suggesting that the linear system model well-estimates the current approach.

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

The autonomic control and functional significance of the changes in heart rate associated with air breathing in the jeju, Hoplerythrinus unitaeniatus.

PubMed

McKenzie, D J; Campbell, H A; Taylor, E W; Micheli, M; Rantin, F T; Abe, A S

2007-12-01

The jeju is a teleost fish with bimodal respiration that utilizes a modified swim bladder as an air-breathing organ (ABO). Like all air-breathing fish studied to date, jeju exhibit pronounced changes in heart rate (fH) during air-breathing events, and it is believed that these may facilitate oxygen uptake (MO2) from the ABO. The current study employed power spectral analysis (PSA) of fH patterns, coupled with instantaneous respirometry, to investigate the autonomic control of these phenomena and their functional significance for the efficacy of air breathing. The jeju obtained less than 5% of total MO2 (MtO2) from air breathing in normoxia at 26 degrees C, and PSA of beat-to-beat variability in fH revealed a pattern similar to that of unimodal water-breathing fish. In deep aquatic hypoxia (water PO2)=1 kPa) the jeju increased the frequency of air breathing (fAB) tenfold and maintained MtO2 unchanged from normoxia. This was associated with a significant increase in heart rate variability (HRV), each air breath (AB) being preceded by a brief bradycardia and then followed by a brief tachycardia. These fH changes are qualitatively similar to those associated with breathing in unimodal air-breathing vertebrates. Within 20 heartbeats after the AB, however, a beat-to-beat variability in fH typical of water-breathing fish was re-established. Pharmacological blockade revealed that both adrenergic and cholinergic tone increased simultaneously prior to each AB, and then decreased after it. However, modulation of inhibitory cholinergic tone was responsible for the major proportion of HRV, including the precise beat-to-beat modulation of fH around each AB. Pharmacological blockade of all variations in fH associated with air breathing in deep hypoxia did not, however, have a significant effect upon fAB or the regulation of MtO2. Thus, the functional significance of the profound HRV during air breathing remains a mystery.