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Sample records for breath measured blood

  1. Comparison of spectroscopically measured tissue alcohol concentration to blood and breath alcohol measurements

    NASA Astrophysics Data System (ADS)

    Ridder, Trent D.; Ver Steeg, Benjamin J.; Laaksonen, Bentley D.

    2009-09-01

    Alcohol testing is an expanding area of interest due to the impacts of alcohol abuse that extend well beyond drunk driving. However, existing approaches such as blood and urine assays are hampered in some testing environments by biohazard risks. A noninvasive, in vivo spectroscopic technique offers a promising alternative, as no body fluids are required. The purpose of this work is to report the results of a 36-subject clinical study designed to characterize tissue alcohol measured using near-infrared spectroscopy relative to venous blood, capillary blood, and breath alcohol. Comparison of blood and breath alcohol concentrations demonstrated significant differences in alcohol concentration [root mean square of 9.0 to 13.5 mg/dL] that were attributable to both assay accuracy and precision as well as alcohol pharmacokinetics. A first-order kinetic model was used to estimate the contribution of alcohol pharmacokinetics to the differences in concentration observed between the blood, breath, and tissue assays. All pair-wise combinations of alcohol assays were investigated, and the fraction of the alcohol concentration variance explained by pharmacokinetics ranged from 41.0% to 83.5%. Accounting for pharmacokinetic concentration differences, the accuracy and precision of the spectroscopic tissue assay were found to be comparable to those of the blood and breath assays.

  2. Laser speckle contrast imaging of blood flow from anesthetized mice: correcting drifts in measurements due to breathing movements

    NASA Astrophysics Data System (ADS)

    Nogueira, Gesse E. C.; Ribeiro, Márcio A. C.; Campos, Juliane C.; Ferreira, Julio C. B.

    2015-06-01

    Background: Laser speckle contrast imaging allows non-invasive assessment of cutaneous blood flow. Although the technique is attractive to measure a quantity related to the skin blood flow (SBF) in anesthetized animal models, movements from breathing can mask the SBF signal. As a consequence, the measurement is overestimated because a variable amount of a DC component due to the breathing movements is added to the SBF signal. Objective: To evaluate a method for estimating the background level of the SBF signal, rejecting artefacts from breathing. Methods: A baseline correction method used for accurate DNA sequencing was evaluated, based on estimating the background level of a signal in small temporal sliding-windows. The method was applied to evaluate a mouse model of hindlimb ischemia. SBF signals from hindlimbs of anesthetized C57BL/6 mice (n=13) were registered. The mean SBF (Fi and Fc from ischemic and control hindlimbs) were computed from the registers and from the corresponding estimated background levels (Fib and Fcb from ischemic and control hindlimbs). Results: The mean values of the percentages (a measure of ischemia) MI = (Fi/Fc).100 and MIb = (Fib/Fcb).100 were computed to be 30+/-4% and 23+/-3% respectively (mean +/- SE). Evidences of statistical differences between both, ischemic and control hindlimbs, were obtained (p<0.05, paired student-t). The mean error [(MI-MIb)/MIb].100 obtained was 45+/-14% (mean+/-SE). Conclusion: The recovery of a corrupted SBF signal by breathing artefacts is feasible, allowing more accurate measurements.

  3. Breath measurements as volatile organic compound biomarkers.

    PubMed Central

    Wallace, L; Buckley, T; Pellizzari, E; Gordon, S

    1996-01-01

    A brief review of the uses of breath analysis in studies of environmental exposure to volatile organic compounds (VOCs) is provided. The U.S. Environmental Protection Agency's large-scale Total Exposure Assessment Methodology Studies have measured concentrations of 32 target VOCs in the exhaled breath of about 800 residents of various U.S. cities. Since the previous 12-hr integrated personal air exposures to the same chemicals were also measured, the relation between exposure and body burden is illuminated. Another major use of the breath measurements has been to detect unmeasured pathways of exposure; the major impact of active smoking on exposure to benzene and styrene was detected in this way. Following the earlier field studies, a series of chamber studies have provided estimates of several important physiological parameters. Among these are the fraction, f, of the inhaled chemical that is exhaled under steady-state conditions and the residence times. tau i in several body compartments, which may be associated with the blood (or liver), organs, muscle, and fat. Most of the targeted VOCs appear to have similar residence times of a few minutes, 30 min, several hours, and several days in the respective tissue groups. Knowledge of these parameters can be helpful in estimating body burden from exposure or vice versa and in planning environmental studies, particularly in setting times to monitor breath in studies of the variation with time of body burden. Improvements in breath methods have made it possible to study short-term peak exposure situations such as filling a gas tank or taking a shower in contaminated water. PMID:8933027

  4. Interactions between breathing rate and low-frequency fluctuations in blood pressure and cardiac intervals.

    PubMed

    Horsman, H M; Peebles, K C; Tzeng, Y C

    2015-10-01

    Evidence derived from spontaneous measures of cardiovagal baroreflex sensitivity (BRS) suggests that slow breathing at 6 breaths/min augments BRS. However, increases in BRS associated with slow breathing may simply reflect the frequency-dependent nature of the baroreflex rather than the modulation of baroreflex function by changes in breathing rate per se. To test this hypothesis we employed a crossover study design (n = 14) wherein breathing rate and systolic arterial blood pressure (SAP) oscillation induced via the application of oscillating lower body negative pressure (OLBNP) were independently varied at fixed frequencies. Breathing rate was controlled at 6 or 10 breaths/min with the aid of a metronome, and SAP oscillations were driven at 0.06 Hz and 0.1 Hz using OLBNP. The magnitudes of SAP and R-R interval (cardiac period) oscillations were quantified using power spectral analysis, and the transfer function gain between SAP and R-R interval was used to estimate BRS. Linear mixed-effects models were used to examine the main effects and interactions between breathing rate and OLBNP frequency. There was no statistical interaction between breathing and OLBNP frequency (P = 0.59), indicating that the effect of breathing rate on BRS did not differ according to OLBNP frequency (and vice versa). Additionally, there was no main effect for breathing rate (P = 0.28). However, we observed a significant main effect for OLBNP frequency (P = 0.01) consistent with the frequency-dependent nature of baroreflex. These findings suggest that increases in spectral indices of BRS reflect the frequency dependence of the baroreflex and are not due to slow breathing per se. PMID:26205543

  5. Blood and breath levels of selected volatile organic compounds in healthy volunteers

    PubMed Central

    King, Julian; Klieber, Martin; Unterkofler, Karl; Hinterhuber, Hartmann; Baumann, Matthias

    2016-01-01

    Gas chromatography with mass spectrometric detection (GC-MS) was used to identify and quantify volatile organic compounds in the blood and breath of healthy individuals. Blood and breath volatiles were preconcentrated using headspace solid phase micro-extraction (HS-SPME) and needle trap devices (NTDs), respectively. The study involved a group of 28 healthy test subjects and resulted in the quantification of a total of 74 compounds in both types of samples. The concentrations of the species under study varied between 0.01 and 6700 nmol L−1 in blood and between 0.02 and 2500 ppb in exhaled air. Limits of detection (LOD) ranged from 0.01 to 270 nmol L−1 for blood compounds and from 0.01 to 0.7 ppb for breath species. Relative standard deviations for both measurement regimes varied from 1.5 to 14%. The predominant chemical classes among the compounds quantified were hydrocarbons (24), ketones (10), terpenes (8), heterocyclic compounds (7) and aromatic compounds (7). Twelve analytes were found to be highly present in both blood and exhaled air (with incidence rates higher than 80%) and for 32 species significant differences (Wilcoxon signed-rank test) between room air and exhaled breath were observed. By comparing blood, room air and breath levels in parallel, a tentative classification of volatiles into endogenous and exogenous compounds can be achieved. PMID:23435188

  6. 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

  7. Longitudinal study (32 years) of exercise tolerance, breathing response, blood pressure, and blood lipids in young men.

    PubMed

    Gillum, R F; Taylor, H L; Anderson, J; Blackburn, H

    1981-01-01

    Changes in exercise tolerance, blood lipids, and blood pressure from youth to middle age was studied in 106 subjects followed 32 years. In addition, the responses to cold pressor and CO2 stress were studied as correlates of future lipids and blood pressure. Treadmill exercise test, cold pressor test, response to breathing a mixture of 6% CO2, and 21% O2, for 5 minutes, blood pressure, and lipid measurements were performed in 1947 when subjects were 20 +/- 2 years old. Exercise, blood pressure and lipid tests were repeated in 1979. Tracking of blood pressure and pulse response to exercise over the period was demonstrated. Baseline exercise response correlated with future blood pressure, cholesterol, triglycerides, and high density lipoproteins. Change in exercise pulse rate over the period correlated with change in cholesterol. Cold pressor systolic blood pressure response correlated with future systolic blood pressure and triglycerides. Pulse and blood pressure response to CO2 breathing correlated with cholesterol, triglyceride and high density lipoprotein 32 years later. These correlations were independent of baseline values of the variables and body mass index. Individuals who were judged "fit" (exercise pulse rise less than median) at both baseline and follow-up had the best cardiovascular risk profile (blood pressure and lipids). Blood pressure and pulse response to exercise tracked between ages 20 and 50. Exercise, cold pressor, and CO2 responses in youth correlated with blood lipid levels in middle age. PMID:6810858

  8. Blood pressure measurement

    MedlinePlus

    Diastolic blood pressure; Systolic blood pressure; Blood pressure reading; Measuring blood pressure ... your health care provider will wrap the blood pressure cuff snugly around your upper arm. The lower ...

  9. Blood pressure measurement

    MedlinePlus

    Diastolic blood pressure; Systolic blood pressure; Blood pressure reading; Measuring blood pressure ... or your health care provider will wrap the blood pressure cuff snugly around your upper arm. The ...

  10. Increased Cerebral Blood Flow Velocity in Children with Mild Sleep-Disordered Breathing

    PubMed Central

    Hill, Catherine M.; Hogan, Alexandra M.; Onugha, Nwanneka; Harrison, Dawn; Cooper, Sara; McGrigor, Victoria J.; Datta, Avijit; Kirkham, Fenella J.

    2007-01-01

    polysomnography. Weight, height, and head circumference were measured in all of the children. BMI and occipitofrontal circumference z scores were computed. Resting systolic and diastolic blood pressure were obtained. Both sleep-disordered breathing children and the age- and BMI-similar controls were assessed using the Behavior Rating Inventory of Executive Function (BRIEF), Neuropsychological Test Battery for Children (NEPSY) visual attention and visuomotor integration, and IQ assessment (Wechsler Preschool and Primary Scale of Intelligence Version III). Transcranial Doppler was performed using a TL2-64b 2-MHz pulsed Doppler device between 2 PM and 7 PM in all of the patients and the majority of controls while awake. Time-averaged mean of the maximal cerebral blood flow velocities was measured in the left and right middle cerebral artery and the higher used for analysis. Results Twenty-one snoring children had an apnea/hypopnea index <5, consistent with mild sleep-disordered breathing below the conventional threshold for surgical intervention. Compared with 17 nonsnoring controls, these children had significantly raised middle cerebral artery blood flow velocities. There was no correlation between cerebral blood flow velocities and BMI or systolic or diastolic blood pressure indices. Exploratory analyses did not reveal any significant associations with apnea/hypopnea index, apnea index, hypopnea index, mean pulse oxygen saturation, lowest pulse oxygen saturation, accumulated time at pulse oxygen saturation <90%, or respiratory arousals when examined in separate bivariate correlations or in aggregate when entered simultaneously. Similarly, there was no significant association between cerebral blood flow velocities and parental estimation of child’s exposure to sleep-disordered breathing. However, it is important to note that whereas the sleep-disordered breathing group did not exhibit significant hypoxia at the time of study, it was unclear to what extent this may have been a

  11. 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. PMID:19696356

  12. Spleen volume and blood flow response to repeated breath-hold apneas.

    PubMed

    Baković, Darija; Valic, Zoran; Eterović, Davor; Vukovic, Ivica; Obad, Ante; Marinović-Terzić, Ivana; Dujić, Zeljko

    2003-10-01

    The purpose of this study was 1) to answer whether the reduction in spleen size in breath-hold apnea is an active contraction or a passive collapse secondary to reduced splenic arterial blood flow and 2) to monitor the spleen response to repeated breath-hold apneas. Ten trained apnea divers and 10 intact and 7 splenectomized untrained persons repeated five maximal apneas (A1-A5) with face immersion in cold water, with 2 min interposed between successive attempts. Ultrasonic monitoring of the spleen and noninvasive cardiopulmonary measurements were performed before, between apneas, and at times 0, 10, 20, 40, and 60 min after the last apnea. Blood flows in splenic artery and splenic vein were not significantly affected by breath-hold apnea. The duration of apneas peaked after A3 (143, 127, and 74 s in apnea divers, intact, and splenectomized persons, respectively). A rapid decrease in spleen volume ( approximately 20% in both apnea divers and intact persons) was mainly completed throughout the first apnea. The spleen did not recover in size between apneas and only partly recovered 60 min after A5. The well-known physiological responses to apnea diving, i.e., bradycardia and increased blood pressure, were observed in A1 and remained unchanged throughout the following apneas. These results show rapid, probably active contraction of the spleen in response to breath-hold apnea in humans. Rapid spleen contraction and its slow recovery may contribute to prolongation of successive, briefly repeated apnea attempts. PMID:12819225

  13. An analysis of estimation of pulmonary blood flow by the single-breath method

    NASA Technical Reports Server (NTRS)

    Srinivasan, R.

    1986-01-01

    The single-breath method represents a simple noninvasive technique for the assessment of capillary blood flow across the lung. However, this method has not gained widespread acceptance, because its accuracy is still being questioned. A rigorous procedure is described for estimating pulmonary blood flow (PBF) using data obtained with the aid of the single-breath method. Attention is given to the minimization of data-processing errors in the presence of measurement errors and to questions regarding a correction for possible loss of CO2 in the lung tissue. It is pointed out that the estimations are based on the exact solution of the underlying differential equations which describe the dynamics of gas exchange in the lung. The reported study demonstrates the feasibility of obtaining highly reliable estimates of PBF from expiratory data in the presence of random measurement errors.

  14. Regulation of brain blood flow and oxygen delivery in elite breath-hold divers.

    PubMed

    Willie, Christopher K; Ainslie, Philip N; Drvis, Ivan; MacLeod, David B; Bain, Anthony R; Madden, Dennis; Maslov, Petra Zubin; Dujic, Zeljko

    2015-01-01

    The roles of involuntary breathing movements (IBMs) and cerebral oxygen delivery in the tolerance to extreme hypoxemia displayed by elite breath-hold divers are unknown. Cerebral blood flow (CBF), arterial blood gases (ABGs), and cardiorespiratory metrics were measured during maximum dry apneas in elite breath-hold divers (n=17). To isolate the effects of apnea and IBM from the concurrent changes on ABG, end-tidal forcing ('clamp') was then used to replicate an identical temporal pattern of decreasing arterial PO2 (PaO2) and increasing arterial PCO2 (PaCO2) while breathing. End-apnea PaO2 ranged from 23 to 37 mm Hg (30 ± 7 mm Hg). Elevation in mean arterial pressure was greater during apnea than during clamp reaching +54 ± 24% versus 34 ± 26%, respectively; however, CBF increased similarly between apnea and clamp (93.6 ± 28% and 83.4 ± 38%, respectively). This latter observation indicates that during the overall apnea period IBM per se do not augment CBF and that the brain remains sufficiently protected against hypertension. Termination of apnea was not determined by reduced cerebral oxygen delivery; despite 40% to 50% reductions in arterial oxygen content, oxygen delivery was maintained by commensurately increased CBF. PMID:25370857

  15. Response of choroidal blood flow to carbogen breathing in smokers and non-smokers

    PubMed Central

    Wimpissinger, B; Resch, H; Berisha, F; Weigert, G; Schmetterer, L; Polak, K

    2004-01-01

    Aim: To investigate a potential difference in ocular vascular reactivity during carbogen breathing in optic nerve head, choroid, and retina between healthy smokers and non-smokers. Methods: 25 (13 smokers and 12 non-smokers) healthy male volunteers participated in this observer masked, two cohort study. During inhalation of carbogen (5% CO2 and 95% O2) over 10 minutes measurements were taken using laser Doppler flowmetry to assess submacular choroidal and optic nerve head blood flow, laser interferometry to assess fundus pulsation amplitudes, and retinal vessel analyser (RVA) to assess retinal vessel diameters. Results: At baseline choroidal blood flow was higher (p = 0.018, ANOVA) in smokers than in non-smokers. During administration of carbogen the response in choroidal blood flow was significantly different between the two groups: there was an increase in non-smokers after carbogen breathing (p = 0.048) compared with relatively stable blood flow in smokers (p = 0.049 between groups, ANOVA). A similar response pattern was seen for fundus pulsation amplitude, which increased notably after carbogen breathing in non-smokers but not in smokers (p<0.001 between groups, ANOVA). Optic nerve head blood flow and retinal vessel diameters were reduced in both groups to a comparable degree during carbogen breathing. Conclusion: The study indicated abnormal choroidal vascular reactivity in chronic smokers. These early haemodynamic changes may be related to the increased risk to smokers of developing ocular vascular diseases. The specific mechanisms underlying abnormal choroidal vascular reactivity in chronic smokers remain to be characterised. PMID:15148211

  16. Monitoring of rapid blood pH variations by CO detection in breath with tunable diode laser

    NASA Astrophysics Data System (ADS)

    Kouznetsov, Andrian I.; Stepanov, Eugene V.; Zyrianov, Pavel V.; Shulagin, Yurii A.; Diachenko, Alexander I.; Gurfinkel, Youri I.

    1997-06-01

    Detection of endogenous carbon monoxide content in breath with tunable diode lasers (TDL) was proposed for noninvasive monitoring of rapid blood pH variation. Applied approach is based on high sensitivity of the haemoglobin and myoglobin affinity for CO to blood pH value and an ability to detect rapidly small variations of CO content in expired air. Breath CO absorption in 4.7 micrometers spectral region was carefully measured using PbSSe tunable diode laser that can provide 1 ppb CO concentration sensitivity and 10 s time constant. Applied TDL gas analyzer was used to monitor expired air of studied persons in physiological tests including hyperventilation and physical load. Simultaneous blood tests were conducted to demonstrate correlation between blood and breath chemical parameters.

  17. Measurement of nitric oxide in human exhaled breath

    SciTech Connect

    Gordon, S.M.; Spicer, C.W.; Ollison, W.M.

    1997-12-31

    This project was initiated to confirm the reliability of nitric oxide (NO) measurement in the breath matrix, using two different analytical techniques - ozone and luminol chemiluminescence - and to corroborate literature reports of elevated breath NO values. To measure peak oral and nasal NO levels, subjects performed slow vital capacity and breath holding maneuvers directly into the monitors through the mouth and the nose, respectively. Additional measurements were made using normal breathing techniques. Initial interferent tests indicate that measured NO signals are real and are not confounded by measurement artifacts. Similar results were obtained using the two independent analytical methods in dry or humid air. The NO signal was unaffected by maximum concentrations of potential breath interferents, such as sulfur compounds and alkenes. The measured breath NO concentrations were greater than typical room air levels and differed significantly with the breathing technique used. During these tests room air averaged 4-5 ppb NO. Peak oral NO levels were 4.3 {+-} 1.5 ppb during a slow vital capacity maneuver and 8.0 {+-} 5.0 ppb during a breath holding maneuver. By contrast, higher peak nasal NO levels were measured for both slow vital capacity (17.8 {+-} 7.8 ppb) and breath holding maneuvers (45.4 {+-} 29.5 ppb).

  18. The acute effect of mouth only breathing on time to completion, heart rate, rate of perceived exertion, blood lactate, and ventilatory measures during a high-intensity shuttle run sequence.

    PubMed

    Meir, Rudi; Zhao, Guang-Gao; Zhou, Shi; Beavers, Rosalind; Davie, Allan

    2014-04-01

    This study investigated the effect of restricting nasal breathing during a series of 20-m shuttle runs. Ten male participants (mean age = 21.7 ± 2.4 years, height = 1.80 ± 0.62 m, mass = 79.2 ± 10.4 kg, sum of 4 skinfolds = 54.5 ± 7.8 mm) were required to either (a) dive on the ground and complete a rolling sequence (condition = GRD) or (b) complete the shuttles while staying on their feet and tagging the line with 1 foot, at the end of each 20-m segment (condition = STD). The shuttle runs were completed with and without a nose clip (no clip = nc; with a clip = clip) under 4 different trial conditions in a randomized order (GRDnc; GRDclip; STDnc; and STDclip), requiring the participants to return on 4 separate occasions separated by 5-7 days. Heart rate was recorded throughout each trial, and the rate of perceived exertion (RPE) was measured at the completion of each shuttle sequence. Pretrial and posttrial lactate and respiratory function measures were also recorded. The general linear model with repeated measures analysis indicated that there was a significant effect for Roll (GRD > STD) (p ≤ 0.05) but not for Clip (p > 0.05) on total time to completion in the trials. There was no significant interaction of the conditions (Roll × Clip) for RPE (p > 0.05). Similarly, there was no significant effect for blood lactate measured 3 minutes post the last shuttle for Roll (p > 0.05) and Clip (p > 0.05). There was a significant main effect on the HR across all 6 time points (i.e., pre, intervals 1-4 and 10 minutes post) (p ≤ 0.05) and for Roll (GRD > STD) (p ≤ 0.05), but not for Clip (p > 0.05). No significant effect of Roll or Clip was found for any of the recorded ventilation measures (p > 0.05). On the basis of these findings, the use of restricted nasal breathing, while performing a high-intensity shuttle sequence as a method of increasing the acute training effect on athletes, is questionable, so strength and conditioning coaches should carefully consider

  19. Blood Pressure and Heart Rate Variability during Yoga-Based Alternate Nostril Breathing Practice and Breath Awareness

    PubMed Central

    Telles, Shirley; Sharma, Sachin Kumar; Balkrishna, Acharya

    2014-01-01

    Background Previous research has shown a reduction in blood pressure (BP) immediately after the practice of alternate nostril yoga breathing (ANYB) in normal healthy male volunteers and in hypertensive patients of both sexes. The BP during ANYB has not been recorded. Material/Methods Participants were 26 male volunteers (group mean age ±SD, 23.8±3.5 years). We assessed (1) heart rate variability, (2) non-invasive arterial BP, and (3) respiration rate, during (a) ANYB and (b) breath awareness (BAW) sessions. Each session was 25 minutes. We performed assessments at 3 time points: Pre (5 minutes), during (15 minutes; for ANYB or BAW) and Post (5 minutes). A naïve-to-yoga control group (n=15 males, mean age ±SD 26.1±4.0 years) were assessed while seated quietly for 25 minutes. Results During ANYB there was a significant decrease (repeated measures ANOVA) in systolic BP and respiration rate; while RMSSD (the square root of the mean of the sum of squares of differences between adjacent NN intervals) and NN50 (the number of interval differences of successive normal to normal intervals greater than 50 ms) significantly increased. During BAW respiration rate decreased. In contrast, respiration rate increased during the control state. ANYB and BAW were significantly different (2-factor ANOVA) in RMSSD and respiration rate. BAW and control were different with respect to respiration rate. Conclusions The results suggest that vagal activity increased during and after ANYB, which could have contributed to the decrease in BP and changes in the HRV. PMID:25408140

  20. MEASUREMENT METHOD FOR VOLATILE METABOLIC BIOMARKERS IN EXHALED BREATH CONDENSATE

    EPA Science Inventory

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

  1. Measuring breath acetone for monitoring fat loss: Review

    PubMed Central

    2015-01-01

    Objective Endogenous acetone production is a by‐product of the fat metabolism process. Because of its small size, acetone appears in exhaled breath. Historically, endogenous acetone has been measured in exhaled breath to monitor ketosis in healthy and diabetic subjects. Recently, breath acetone concentration (BrAce) has been shown to correlate with the rate of fat loss in healthy individuals. In this review, the measurement of breath acetone in healthy subjects is evaluated for its utility in predicting fat loss and its sensitivity to changes in physiologic parameters. Results BrAce can range from 1 ppm in healthy non‐dieting subjects to 1,250 ppm in diabetic ketoacidosis. A strong correlation exists between increased BrAce and the rate of fat loss. Multiple metabolic and respiratory factors affect the measurement of BrAce. BrAce is most affected by changes in the following factors (in descending order): dietary macronutrient composition, caloric restriction, exercise, pulmonary factors, and other assorted factors that increase fat metabolism or inhibit acetone metabolism. Pulmonary factors affecting acetone exchange in the lung should be controlled to optimize the breath sample for measurement. Conclusions When biologic factors are controlled, BrAce measurement provides a non‐invasive tool for monitoring the rate of fat loss in healthy subjects. PMID:26524104

  2. Blood and breath profiles of volatile organic compounds in patients with end-stage renal disease

    PubMed Central

    2014-01-01

    Background Monitoring of volatile organic compounds (VOCs) in exhaled breath shows great potential as a non-invasive method for assessing hemodialysis efficiency. In this work we aim at identifying and quantifying of a wide range of VOCs characterizing uremic breath and blood, with a particular focus on species responding to the dialysis treatment. Methods Gas chromatography with mass spectrometric detection coupled with solid-phase microextraction as pre-concentration method. Results A total of 60 VOCs were reliably identified and quantified in blood and breath of CKD patients. Excluding contaminants, six compounds (isoprene, dimethyl sulfide, methyl propyl sulfide, allyl methyl sulfide, thiophene and benzene) changed their blood and breath levels during the hemodialysis treatment. Conclusions Uremic breath and blood patterns were found to be notably affected by the contaminants from the extracorporeal circuits and hospital room air. Consequently, patient exposure to a wide spectrum of volatile species (hydrocarbons, aldehydes, ketones, aromatics, heterocyclic compounds) is expected during hemodialysis. Whereas highly volatile pollutants were relatively quickly removed from blood by exhalation, more soluble ones were retained and contributed to the uremic syndrome. At least two of the species observed (cyclohexanone and 2-propenal) are uremic toxins. Perhaps other volatile substances reported within this study may be toxic and have negative impact on human body functions. Further studies are required to investigate if VOCs responding to HD treatment could be used as markers for monitoring hemodialysis efficiency. PMID:24607025

  3. Multi-window PIV measurements around a breathing manikin

    NASA Astrophysics Data System (ADS)

    Marr, David

    2005-11-01

    The presented work includes multi-scale measurements via a stereo article Image Velocimetry (PIV) system to view a pair of two-component windows of dissimilar scale using a varied focal length. These measurements are taken in the breathing zone of an isothermal breathing manikin (from mouth) in an environmental chamber of average office cubicle dimensions without ventilation and are analogous to an oscillatory jet. From these phase-averaged measurements, we can extract information concerning length scales, turbulence quantities and low dimensional information in order to both determine correlation between data at different length scales as well as continuing research in exposure assessment for the indoor environment. In this talk we will present these turbulence quantities and interpret their influence on the breathing zone. While the largest scale is that of the room itself, we find that the relevant spatial scales associated with the breathing zone are much lower in magnitude. In future experiments, we will expand the multi window PIV technique to include PIV window configured to obtain scales of order the cubicle simultaneously with those of the breathing zone. This will aid in our understanding of the combined impact of these multiple scales on occupant exposure in the indoor environment.

  4. The effects of progressive muscular relaxation and breathing control technique on blood pressure during pregnancy

    PubMed Central

    Aalami, Mahboobeh; Jafarnejad, Farzaneh; ModarresGharavi, Morteza

    2016-01-01

    Background: Hypertensive disorders in pregnancy are the main cause of maternal and fetal mortality; however, they have no definite effective treatment. The researchers aimed to study the effects of progressive muscular relaxation and breathing control technique on blood pressure (BP) during pregnancy. Materials and Methods: This three-group clinical trial was conducted in Mashhad health centers and governmental hospitals. Sixty pregnant (after 20 weeks of gestational age) women with systolic BP ≥ 135 mmHg or diastolic BP ≥ 85 mmHg were assigned to three groups. Progressive muscular relaxation and breathing control exercises were administered to the two experimental groups once a week in person and in the rest of the days by instructions given on a CD for 4 weeks. BP was checked before and after the interventions. BP was measured before and after 15 min subjects' waiting without any especial intervention in the control group. Results: After 4 weeks of intervention, the systolic (by a mean of 131.3 to 117.2, P = 0.001 and by a mean of 131.05 to 120.5, P = 0.004, respectively) and diastolic (by a mean of 79.2 to 72.3, P = 0.001 and by a mean of 80.1 to 76.5, P = 0.047, respectively) BPs were significantly decreased in progressive muscular relaxation and breathing control groups, but they were not statistically significant in the control group. Conclusions: The interventions were effective on decreasing systolic and diastolic BP to normal range after 4 weeks in both the groups. The effects of both the interventions were more obvious on systolic BP compared to diastolic BP. PMID:27186213

  5. Tissue gas and blood analyses of human subjects breathing 80% argon and 20% oxygen

    NASA Technical Reports Server (NTRS)

    Horrigan, D. J.; Wells, C. H.; Guest, M. M.; Hart, G. B.; Goodpasture, J. E.

    1979-01-01

    Eight human volunteers, individually studied in a hyperbaric chamber, breathed: (1) air at 1 ATA; (2) 80% argon and 20% oxygen at 1 ATA for 30 min; (3) air at 1 ATA for 30 min; (4) 100% O2 at 1 ATA for 30 min; (5) air at 1 ATA for 30 min; (6) 100% O2 at 2 ATA for 60 min; and (7) 80% argon and 20% oxygen at 1 ATA for 30 min. Oxygen, carbon dioxide, nitrogen, and argon tensions were measured in muscle and subcutaneous tissue by mass spectroscopic analyses. Venous blood obtained at regular intervals was analyzed for coagulation and fibrinolytic factors. Inert gas narcosis was not observed. After breathing argon for 30 min, muscle argon tensions were almost three times the subcutaneous tensions. Argon wash-in mirrored nitrogen wash-out. Argon wash-in and wash-out had no effect on tissue PO2 or PCO2. Coagulation and fibrinolytic changes usually associated with vascular bubbles were absent.

  6. Heart rate and blood pressure responses during hypoxic cycles of a 3-week intermittent hypoxia breathing program in patients at risk for or with mild COPD

    PubMed Central

    Faulhaber, Martin; Gatterer, Hannes; Haider, Thomas; Linser, Tobias; Netzer, Nikolaus; Burtscher, Martin

    2015-01-01

    The aim of this study was to provide information on heart rate and blood pressure responses during a 3-week intermittent hypoxia breathing program in COPD patients. Sixteen participants with COPD symptoms were randomly assigned to a hypoxia or control group and completed a 3-week intermittent hypoxia breathing program (five sessions per week, each consisting of three to five breathing cycles, each cycle lasting 3–5 minutes with 3-minute breaks between cycles). During the breathing cycles, the hypoxia group received hypoxic air (inspired fraction of oxygen 15%–12%), whereas the control group received normal air (sham hypoxia). During the breaks, all participants breathed normoxic room air. Arterial oxygen saturation, systolic and diastolic blood pressure, and heart rate were measured during the normoxic and hypoxic/sham hypoxic periods. For each breathing cycle, changes from normoxia to hypoxia/sham hypoxia were calculated, and changes were averaged for each of the 15 sessions and for each week. Changes in arterial oxygen saturation were significantly different between groups in the course of the 3 weeks (two-way analysis of variance for repeated measures), with post hoc differences in weeks 1, 2, and 3. During the course of the intermittent hypoxia application, no between-group differences were detected for blood pressure or rate pressure product values. Changes in heart rate were significantly different between groups in the course of the 3 weeks (two-way analysis of variance for repeated measures), with post hoc differences only in week 3. Averages over all 15 sessions were significantly higher in the hypoxia group for heart rate and rate pressure product, and tended to be increased for systolic blood pressure. The applied intermittent hypoxia breathing program resulted in specific and moderate heart rate and blood pressure responses, and did not provoke a progressive increase in blood pressure during the hypoxic cycles in the course of the application. PMID

  7. Heart rate and blood pressure responses during hypoxic cycles of a 3-week intermittent hypoxia breathing program in patients at risk for or with mild COPD.

    PubMed

    Faulhaber, Martin; Gatterer, Hannes; Haider, Thomas; Linser, Tobias; Netzer, Nikolaus; Burtscher, Martin

    2015-01-01

    The aim of this study was to provide information on heart rate and blood pressure responses during a 3-week intermittent hypoxia breathing program in COPD patients. Sixteen participants with COPD symptoms were randomly assigned to a hypoxia or control group and completed a 3-week intermittent hypoxia breathing program (five sessions per week, each consisting of three to five breathing cycles, each cycle lasting 3-5 minutes with 3-minute breaks between cycles). During the breathing cycles, the hypoxia group received hypoxic air (inspired fraction of oxygen 15%-12%), whereas the control group received normal air (sham hypoxia). During the breaks, all participants breathed normoxic room air. Arterial oxygen saturation, systolic and diastolic blood pressure, and heart rate were measured during the normoxic and hypoxic/sham hypoxic periods. For each breathing cycle, changes from normoxia to hypoxia/sham hypoxia were calculated, and changes were averaged for each of the 15 sessions and for each week. Changes in arterial oxygen saturation were significantly different between groups in the course of the 3 weeks (two-way analysis of variance for repeated measures), with post hoc differences in weeks 1, 2, and 3. During the course of the intermittent hypoxia application, no between-group differences were detected for blood pressure or rate pressure product values. Changes in heart rate were significantly different between groups in the course of the 3 weeks (two-way analysis of variance for repeated measures), with post hoc differences only in week 3. Averages over all 15 sessions were significantly higher in the hypoxia group for heart rate and rate pressure product, and tended to be increased for systolic blood pressure. The applied intermittent hypoxia breathing program resulted in specific and moderate heart rate and blood pressure responses, and did not provoke a progressive increase in blood pressure during the hypoxic cycles in the course of the application. PMID

  8. Automated Blood Pressure Measurement

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The Vital-2 unit pictured is a semi-automatic device that permits highly accurate blood pressure measurement, even by untrained personnel. Developed by Meditron Instrument Corporation, Milford, New Hampshire, it is based in part on NASA technology found in a similar system designed for automatic monitoring of astronauts' blood pressure. Vital-2 is an advancement over the familiar arm cuff, dial and bulb apparatus customarily used for blood pressure checks. In that method, the physician squeezes the bulb to inflate the arm cuff, which restricts the flow of blood through the arteries. As he eases the pressure on the arm, he listens, through a stethoscope, to the sounds of resumed blood flow as the arteries expand and contract. Taking dial readings related to sound changes, he gets the systolic (contracting) and diastolic (expanding) blood pressure measurements. The accuracy of the method depends on the physician's skill in interpreting the sounds. Hospitals sometimes employ a more accurate procedure, but it is "invasive," involving insertion of a catheter in the artery.

  9. 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.

  10. Prostaglandin E2 decreases fetal breathing movements, but not pulmonary blood flow, in fetal sheep.

    PubMed

    Savich, R D; Guerra, F A; Lee, C C; Kitterman, J A

    1995-04-01

    Fetal breathing movements are vital for normal fetal lung growth. Inhibition of these fetal breathing movements is associated with pulmonary hypoplasia. Pulmonary hypoplasia also occurs subsequent to alterations in other factors, such as a significant decrease in pulmonary blood flow. The prostaglandin system is known to have profound effects on both fetal breathing movements and on the pulmonary vascular system. We studied six late-gestation chronically instrumented fetal sheep by using an electromagnetic flow transducer around the left pulmonary artery to determine whether a decrease in fetal breathing movements, subsequent to a continuous infusion of prostaglandin E2 (PGE2), is associated with a decrease in pulmonary blood flow. A continuous PGE2 infusion of 0.88 +/- 0.11 microgram.kg-1.min-1 over 120 min led to a significant decrease in fetal breathing movements (control 40.5 +/- 3.6%, infusion 3.3 +/- 1.6%; P < 0.001). In contrast, the PGE2 infusion had no effect on mean left pulmonary artery blood flow (control 27.7 +/- 9.3 ml.min-1.kg-1, infusion 23.8 +/- 7.0 ml.min-1.kg-1. The PGE2 infusion demonstrated central effects in the percentage of time the fetus was in high-voltage electrocortical activity (control 41.9 +/- 2.5%, infusion 56.5 +/- 5.4%; P < 0.05) and in the amount of time spent in low-voltage electrocortical activity without fetal breathing movements (control 17.5 +/- 2.7%, infusion 40.2 +/- 4.8%; P < 0.05). A significant decrease in the fetal heart rate during the infusion was seen with no effect on either the systemic or pulmonary blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7615458

  11. Fuzzy blood pressure measurement

    NASA Astrophysics Data System (ADS)

    Cuce, Antonino; Di Guardo, Mario; Sicurella, Gaetano

    1998-10-01

    In this paper, an intelligent system for blood pressure measurement is posed together with a possible implementation using an eight bit fuzzy processor. The system can automatically determine the ideal cuff inflation level eliminating the discomfort and misreading caused by incorrect cuff inflation. Using statistics distribution of the systolic and diastolic blood pressure, in the inflation phase, a fuzzy rule system determine the pressure levels at which checking the presence of heart beat in order to exceed the systolic pressure with the minimum gap. The heart beats, characterized through pressure variations, are recognized by a fuzzy classifier.

  12. Lung function measurement with multiple-breath-helium washout system.

    PubMed

    Wang, J-Y; Suddards, M E; Mellor, C J; Owers-Bradley, J R

    2013-04-01

    Multiple-breath-washout (MBW) measurements are regarded as a sensitive technique which can reflect the ventilation inhomogeneity of respiratory airways. Typically nitrogen is used as the tracer gas and is washed out by pure oxygen in multiple-breath-nitrogen washout (MBNW) tests. In this study, instead of using nitrogen, (4)He is used as the tracer gas with smaller gas density which may be able to reach deeper into our lungs in a given time and the helium washout results may be more sensitive to the ventilation inhomogeneity in small airways. A multiple-breath-helium-washout (MBHW) system developed for the lung function study is also presented. Quartz tuning forks with a resonance frequency of 32,768Hz have been used for detecting the change of the respiratory gas density. The resonance frequency of the quartz tuning fork decreases linearly with increasing density of the surrounding gas. Knowing the CO2 concentration from the infrared carbon dioxide detector, the helium concentration can be determined. Results from 14 volunteers (3 mild asthmatics, 4 tobacco smokers, 1 with asthma history, 1 with COPD history, 5 normal) have shown that mild asthmatics have higher ventilation inhomogeneity in either conducting or acinar airways (or both). A feature has been found in washout curve of single breaths from 4 tobacco smokers with different length of smoking history which may indicate the early stage of respiratory ventilation inhomogeneity in acinar airways. PMID:22835436

  13. Breath-hold black blood quantitative T1rho imaging of liver using single shot fast spin echo acquisition

    PubMed Central

    Chan, Queenie; Wáng, Yì-Xiáng J.

    2016-01-01

    Background Liver fibrosis is a key feature in most chronic liver diseases. T1rho magnetic resonance imaging is a potentially important technique for noninvasive diagnosis, severity grading, and therapy monitoring of liver fibrosis. However, it remains challenging to perform robust T1rho quantification of liver on human subjects. One major reason is that the presence of rich blood signal in liver can cause artificially high T1rho measurement and makes T1rho quantification susceptible to motion. Methods A pulse sequence based on single shot fast/turbo spin echo (SSFSE/SSTSE) acquisition, with theoretical analysis and simulation based on the extended phase graph (EPG) algorithm, was presented for breath-hold single slice quantitative T1rho imaging of liver with suppression of blood signal. The pulse sequence was evaluated in human subjects at 3.0 T with 500 Hz spinlock frequency and time-of-spinlock (TSL) 0, 10, 30 and 50 ms. Results Human scan demonstrated that the entire T1rho data sets with four spinlock time can be acquired within a single breath-hold of 10 seconds with black blood effect. T1rho quantification with suppression of blood signal results in significantly reduced T1rho value of liver compared to the results without blood suppression. Conclusions A signal-to-noise ratio (SNR) efficient pulse sequence was reported for T1rho quantification of liver. The black blood effect, together with a short breath-hold, mitigates the risk of quantification errors as would occur in the conventional methods. PMID:27190769

  14. How Ecosystems Breathe: Measuring Respiration of Soil

    NASA Astrophysics Data System (ADS)

    McTammany, M. E.

    2005-05-01

    Curriculum for general ecology labs often uses in-lab exercises and computer simulations to demonstrate ecological principles rather than experimental field projects. In addition, ecosystem processes can be difficult to incorporate into general ecology labs because the techniques require sophisticated equipment or complex field designs. As an alternative to in-lab projects, I have integrated field measurement of soil respiration into my general ecology lab to teach students aspects of experimental design (sampling, replication, error, etc.) and to demonstrate how organism-level processes operate beyond single organisms in nature and are influenced by environmental conditions. In a program laden with biomedical interests, analogies between organisms and ecosystems are quite appealing to students. Students in my general ecology course complete a 2-week field project in which they measure soil respiration inside a dark microcosm chamber. We use 10% KOH to trap evolved CO2 and titrate unreacted KOH in lab using 1N HCl. The protocol is simple, only requires some chemicals, and can be used in many different habitats (including flower beds on campus) quite easily. Potential experiments could involve varying environmental conditions, such as soil moisture, nutrient availability, gaseous environment, carbon supply, or temperature, to affect soil respiration rate.

  15. Measurement of Ethanol in Gaseous Breath Using a Miniature Gas Chromatograph

    PubMed Central

    Morey, Timothy E.; Booth, Matthew M.; Prather, Robert A.; Nixon, Sara J.; Boissoneault, Jeff; Melker, Richard J.; Goldberger, Bruce A.; Wohltjen, Hank; Dennis, Donn M.

    2011-01-01

    We designed and built a novel, miniature gas chromatograph (mGC) to use exhaled breath to estimate blood ethanol concentrations that may offer GC quality sensitivity and specificity, but with portability, reduced size, and decreased cost. We hypothesized that the mGC would accurately estimate the serum ethanol concentration using exhaled breath. Human subjects (n = 8) were dosed with ethanol employing the Widmark criteria, targeting a blood concentration of 0.08 g/dL. Serum and breath samples were collected concurrently over an hour. Ethanol concentrations in serum were measured using a CLIA-approved laboratory. Ethanol concentrations in conventional breath were assayed using a calibrated mGC or Intoxilyzer 400PA. Data were analyzed using Bland-Altman analysis using serum concentrations as a “gold standard”. For the mGC, the regression line (correlation coefficient), bias, and 95% limits of agreement were y = 1.013x − 0.009 (r = 0.91), −0.008 g/dL, and −0.031 to 0.016 g/dL, respectively, for 30 specimens. For the Intoxilyzer 400PA, the regression line (correlation coefficient), bias, and 95% limits of agreement were y = 0.599x + 0.008 (r = 0.86), −0.024 g/dL, and −0.049 to 0.002 g/dL, respectively, for 71 specimens with a large magnitude effect. We concluded that the mGC, using exhaled breath, performed well to estimate the serum ethanol concentrations. PMID:21439148

  16. 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.

  17. Blood (Breath) Alcohol Concentration Rates of College Football Fans on Game Day

    ERIC Educational Resources Information Center

    Glassman, Tavis; Braun, Robert; Reindl, Diana M.; Whewell, Aubrey

    2011-01-01

    The purpose of this study was to determine the Blood (breath) Alcohol Concentration (BrAC) rates of college football fans on game day. Researchers employed a time-series study design, collecting data at home football games at a large university in the Midwest. Participants included 536 individuals (64.4% male) ages 18-83 (M = 28.44, SD = 12.32).…

  18. [An Examination of Variable Image Positions in the Aortic Valve Blood Flow Using Phase Contrast MRI: Effect of Breath-holding Methods in Healthy Volunteers].

    PubMed

    Nakagawa, Kenichi; Morimoto, Noriyoshi; Fukushima, Sachi

    2015-12-01

    Phase contrast MRI (PC-MRI) is a useful tool for evaluating valvular pathology. In addition, PC-MRI can provide a noninvasive assessment of blood flow in an arbitrary cross section. However, the blood flow measurement with breath-hold or free breath PC-MRI may be different from each other because of intrathoracic pressure changing and variable image position. The aim of this study was to find both the optimal breath-hold technique and the image position. Quantitative flow images were acquired in four planes (ascending aorta: Ao, sino-tubular junction: STJ, valsalva sinus: valsalva, left ventricular outflow tract: LVOT), in healthy subjects (n=10). The study protocol was divided into two parts: (1) stroke volume (SV) measured in each slice positions by using inspiration, expiration, and navigation method during normal breathing and (2) SV measured at each breath-hold techniques in the Ao, STJ, valsalva, and LVOT. As a result, (1) SV of the respective measurement positions were not significant by using inspiration, expiration, and navigation method and (2) LVOT SV was significantly lower than Ao, STJ, and valsalva. PMID:26685835

  19. Effect of inhibition of prostaglandin synthesis on breathing movements and pulmonary blood flow in fetal sheep.

    PubMed

    Savich, R D; Guerra, F A; Lee, C C; Kitterman, J A

    1995-02-01

    During transition from fetal to extrauterine life, respiration increases in incidence and magnitude as pulmonary blood flow dramatically increases. To determine whether alterations in pulmonary blood flow in utero are directly related to alterations in fetal breathing movements (FBM), we studied six chronically instrumented fetal sheep late in gestation to assess the effects of continuous FBM caused by a 4-h infusion of meclofenamate, a prostaglandin synthase inhibitor, on mean pulmonary blood flow to the fetus. We found a striking increase in FBM from 46 +/- 15% (SD) of the time during control to > 85% of the time by 1 h (P < 0.001), with the fetuses exhibiting continuous FBM by the last 1 h of infusion. The mean pulmonary blood flow also increased significantly during the first 90 min of the infusion as the incidences of FBM were increasing (26 +/- 14 and 56 +/- 23 ml.min-1.kg-1 for control and infusion, respectively; P < 0.01). Despite the simultaneous initial increase in FBM and mean pulmonary blood flow, the increase in left pulmonary artery blood flow was not sustained and decreased back to baseline by 2 h, even though the incidence of FBM continued to increase at this time. During the infusion, the mean pulmonary blood flow was not different between the presence or absence of FBM. There were no changes in fetal heart rate or pulmonary or systemic blood pressures during the infusion nor in arterial pH or blood gas tensions. We conclude that this increase in mean pulmonary blood flow in utero was not solely related to the increase in breathing movements. PMID:7759422

  20. Noninvasive Measurement of Plasma Triglycerides and Free Fatty Acids from Exhaled Breath

    PubMed Central

    Minh, Timothy Do Chau; Oliver, Stacy R; Flores, Rebecca L; Ngo, Jerry; Meinardi, Simone; Carlson, Matthew K; Midyett, Jason; Rowland, F Sherwood; Blake, Donald R; Galassetti, Pietro Renato

    2012-01-01

    Background Although altered metabolism has long been known to affect human breath, generating clinically usable metabolic tests from exhaled compounds has proven challenging. If developed, a breath-based lipid test would greatly simplify management of diabetes and serious pathological conditions (e.g., obesity, familial hyperlipidemia, and coronary artery disease), in which systemic lipid levels are a critical risk factor for onset and development of future cardiovascular events. Methods We, therefore, induced controlled fluctuations of plasma lipids (insulin-induced lipid suppression or intravenous infusion of Intralipid) during 4-h in vivo experiments on 23 healthy volunteers (12 males/11 females, 28.0 ± 0.3 years) to find correlations between exhaled volatile organic compounds and plasma lipids. In each subject, plasma triglycerides (TG) and free fatty acids (FFA) concentrations were both directly measured and calculated via individualized prediction equations based on the multiple linear regression analysis of a cluster of 4 gases. In the lipid infusion protocol, we also generated common prediction equations using a maximum of 10 gases. Results This analysis yielded strong correlations between measured and predicted values during both lipid suppression (r = 0.97 for TG; r = 0.90 for FFA) and lipid infusion (r = 0.97 for TG; r = 0.94 for FFA) studies. In our most accurate common prediction model, measured and predicted TG and FFA values also displayed very strong statistical agreement (r = 0.86 and r = 0.81, respectively). Conclusions Our results demonstrate the feasibility of measuring plasma lipids through breath analysis. Optimization of this technology may ultimately lead to the development of portable breath analyzers for plasma lipids, replacing blood-based bioassays. PMID:22401327

  1. Changes in the blood parameters of an air-breathing fish during different respiratory conditions.

    PubMed

    Singh, B R; Thakur, R N; Yadav, A N

    1976-01-01

    Some of the blood parameters recorded in an air-breathing eel, Amphipnous cuchia under normal respiratory condition during non-breeding period (September-April) are haemoglobin (Hb) concentration 19.26%, haematocrit value 56.16%, RBC number 1.71 million/mm3, RBC size 18.86 X 9.70 mum, mean corpuscular haemoglobin (MCH) 113.4 ng, mean corpuscular haemoglobin concentration (MCHC) 34.2%, blood sugar 77 mg% and ascorbic acid 0.435 mg%. The higher concentration of haemoglobin (19.26%) appears to be related to its obligatory air breathing habit and habitat in a water of low oxygen content. Though a definite trend of increase in the haemoglobin and haematocrit concentration with an increase in the body weight of the fish was lacking, variations were clearly marked related to intrinsic activity of the fish connected with different respiratory conditions. Asphyxiation in a submerged but continuous flow of water (liter/h) for 5 1/2 h resulted in an increase in the above-mentioned parameters to an appreciable extent. These increases were 0.23 million/mm3 in the number of erythrocytes, 6.16% in haemoglobin concentration, 10% in haematocrit value, 20% in blood sugar and 35% in ascorbic acid content. The mean corpuscular haemoglobin showed a decline of 6.2%. Exclusive aerial breathing for 5 1/2 h also caused 7.4% increase in haemoglobin concentration, 9.4% in haematocrit value, 0.14 million/mm3 in RBC number, 20% in blood sugar level, 9% in ascorbic acid content but almost no change in mean corpuscular haemoglobin. The average surface area for diffusion of gases appeared to have reduced by 6.8 mum2 per RBC. PMID:61915

  2. The effect of fetal breathing movements on pulmonary blood flow in fetal sheep.

    PubMed

    Savich, R D; Guerra, F A; Lee, C C; Kitterman, J A

    1994-04-01

    In the fetus, normal lung growth requires both fetal breathing movements (FBM) and adequate pulmonary blood flow. We postulated that FBM intermittently increase pulmonary blood flow and may stimulate lung growth through that effect. To test the hypothesis that normal intermittent FBM cause associated intermittent increases in pulmonary blood flow, we studied eight chronically instrumented fetal sheep (gestational ages 125-143 d) on 34 occasions (total study time = 65.7 h). Each fetus had a cuff electromagnetic flow transducer around the left pulmonary artery, electrocortical electrodes, and catheters in the trachea, main pulmonary artery, carotid artery, and amniotic cavity. Mean blood flow though the left pulmonary artery averaged 59 +/- 8 mL/min (mean +/- SEM; per kg: 25 +/- 4 mL/kg/min) and was similar in both the presence (61 +/- 9 mL/min) and absence (57 +/- 7 mL/min) of FBM and during both high and low voltage electrocortical activity. In contrast, in utero phasic pulmonary blood flow varied with FBM, increasing during the inspiratory phase and decreasing during the expiratory phase. Both pulmonary and systemic vascular pressures showed changes in the opposite directions. Arterial pH and blood gas tensions were normal and did not change with FBM or electrocortical activity. We conclude that FBM do not increase mean blood flow through the left pulmonary artery; thus, it is unlikely that FBM stimulate lung growth through changes in pulmonary blood flow. PMID:8047386

  3. Reliability and Determinants of Self-Evaluation of Breathing Questionnaire (SEBQ) Score: A Symptoms-Based Measure of Dysfunctional Breathing.

    PubMed

    Mitchell, A J; Bacon, C J; Moran, R W

    2016-03-01

    Dysfunctional breathing is characterised by an abnormal breathing pattern leading to respiratory symptoms. The 25-item Self Evaluation of Breathing Questionnaire (SEBQ) has been developed to measure breathing-related symptoms and their severity but lacks thorough evaluation. To determine reproducibility, internal consistency and predictors of SEBQ score, 180 participants completed an online SEBQ with additional demographic and lifestyle questions. Two weeks later, 155 of those repeated SEBQ. Test-retest correlation of the SEBQ was high [intraclass correlation coefficient (3, 1) = 0.89; 95 % CI 0.85-0.92]. There was no difference in SEBQ score between test and retest (15.1 (11.6) [mean (SD)] versus 14.7 (12.4); P = 0.4) and the score showed a typical error (standard error of measurement) of 4.0. Internal consistency was high (Cronbach's α = 0.93), and a single factor structure for items was shown. Smoking status, reported respiratory disease, recent respiratory illness and female gender were positively-associated predictors of SEBQ score, and together explained 25.6 % of score variance (P ≤ 0.001). The SEBQ has high test-retest reproducibility and its score may be predicted by current smoking, chronic respiratory disease, recent respiratory illness and female gender, thus may be a useful clinical screening tool for dysfunctional breathing. PMID:26400252

  4. Influence of breathing frequency on the pattern of respiratory sinus arrhythmia and blood pressure: old questions revisited.

    PubMed

    Sin, P Y W; Galletly, D C; Tzeng, Y C

    2010-05-01

    Respiratory sinus arrhythmia (RSA) is classically described as a vagally mediated increase and decrease in heart rate concurrent with inspiration and expiration, respectively. However, although breathing frequency is known to alter this temporal relationship, the precise nature of this phase dependency and its relationship to blood pressure remains unclear. In 16 subjects we systematically examined the temporal relationships between respiration, RSA, and blood pressure by graphically portraying cardiac interval (R-R) and systolic blood pressure (SBP) variations as a function of the respiratory cycle (pattern analysis), during incremental stepwise paced breathing. The principal findings were 1) the time interval between R-R maximum and expiration onset remained the same ( approximately 2.5-3.0 s) irrespective of breathing frequency (P = 0.10), whereas R-R minimum progressively shifted from expiratory onset into midinspiration with slower breathing (P < 0.0001); 2) there is a clear qualitative distinction between pre- versus postinspiratory cardiac acceleration during slow (0.10 Hz) but not fast (0.20 Hz) breathing; 3) the time interval from inspiration onset to SBP minimum (P = 0.16) and from expiration onset to SBP maximum (P = 0.26) remained unchanged across breathing frequencies; 4) SBP maximum and R-R maximum maintained an unchanged temporal alignment of approximately 1.1 s irrespective of breathing frequency (P = 0.84), whereas the alignment between SBP minimum and R-R minimum was inconstant (P > 0.0001); and 5) beta(1)-adrenergic blockade did not influence the respiration-RSA relationships or distinct RSA patterns observed during slow breathing, suggesting that temporal dependencies associated with alterations in breathing frequency are unrelated to cardiac sympathetic modulation. Collectively, these results illustrate nonlinear respiration-RSA-blood pressure relationships that may yield new insights to the fundamental mechanism of RSA in humans. PMID:20228262

  5. Noninvasive measurement of plasma glucose from exhaled breath in healthy and type 1 diabetic subjects

    PubMed Central

    Oliver, Stacy R.; Ngo, Jerry; Flores, Rebecca; Midyett, Jason; Meinardi, Simone; Carlson, Matthew K.; Rowland, F. Sherwood; Blake, Donald R.; Galassetti, Pietro R.

    2011-01-01

    Effective management of diabetes mellitus, affecting tens of millions of patients, requires frequent assessment of plasma glucose. Patient compliance for sufficient testing is often reduced by the unpleasantness of current methodologies, which require blood samples and often cause pain and skin callusing. We propose that the analysis of volatile organic compounds (VOCs) in exhaled breath can be used as a novel, alternative, noninvasive means to monitor glycemia in these patients. Seventeen healthy (9 females and 8 males, 28.0 ± 1.0 yr) and eight type 1 diabetic (T1DM) volunteers (5 females and 3 males, 25.8 ± 1.7 yr) were enrolled in a 240-min triphasic intravenous dextrose infusion protocol (baseline, hyperglycemia, euglycemia-hyperinsulinemia). In T1DM patients, insulin was also administered (using differing protocols on 2 repeated visits to separate the effects of insulinemia on breath composition). Exhaled breath and room air samples were collected at 12 time points, and concentrations of ∼100 VOCs were determined by gas chromatography and matched with direct plasma glucose measurements. Standard least squares regression was used on several subsets of exhaled gases to generate multilinear models to predict plasma glucose for each subject. Plasma glucose estimates based on two groups of four gases each (cluster A: acetone, methyl nitrate, ethanol, and ethyl benzene; cluster B: 2-pentyl nitrate, propane, methanol, and acetone) displayed very strong correlations with glucose concentrations (0.883 and 0.869 for clusters A and B, respectively) across nearly 300 measurements. Our study demonstrates the feasibility to accurately predict glycemia through exhaled breath analysis over a broad range of clinically relevant concentrations in both healthy and T1DM subjects. PMID:21467303

  6. Perspective use of direct human blood as an energy source in air-breathing hybrid microfluidic fuel cells

    NASA Astrophysics Data System (ADS)

    Dector, A.; Escalona-Villalpando, R. A.; Dector, D.; Vallejo-Becerra, V.; Chávez-Ramírez, A. U.; Arriaga, L. G.; Ledesma-García, J.

    2015-08-01

    This work presents a flexible and light air-breathing hybrid microfluidic fuel cell (HμFC) operated under biological conditions. A mixture of glucose oxidase, glutaraldehyde, multi-walled carbon nanotubes and vulcan carbon (GOx/VC-MWCNT-GA) was used as the bioanode. Meanwhile, integrating an air-exposed electrode (Pt/C) as the cathode enabled direct oxygen delivery from air. The microfluidic fuel cell performance was evaluated using glucose obtained from three different sources as the fuel: 5 mM glucose in phosphate buffer, human serum and human blood. For the last fuel, an open circuit voltage and maximum power density of 0.52 V and 0.20 mW cm-2 (at 0.38 V) were obtained respectively; meanwhile the maximum current density was 1.1 mA cm-2. Furthermore, the stability of the device was measured in terms of recovery after several polarization curves, showing excellent results. Although this air-breathing HμFC requires technological improvements before being tested in a biomedical device, it represents the best performance to date for a microfluidic fuel cell using human blood as glucose source.

  7. Optical measures of changes in cerebral vascular tone during voluntary breath holding and a Sternberg memory task.

    PubMed

    Tan, Chin Hong; Low, Kathy A; Schneider-Garces, Nils; Zimmerman, Benjamin; Fletcher, Mark A; Maclin, Edward L; Chiarelli, Antonio M; Gratton, Gabriele; Fabiani, Monica

    2016-07-01

    The human cerebral vasculature responds to changes in blood pressure and demands for oxygenation via cerebral autoregulation. Changes in cerebrovascular tone (vasoconstriction and vasodilation) also mediate the changes in blood flow measured by the BOLD fMRI signal. This cerebrovascular reactivity is known to vary with age. In two experiments, we demonstrate that cerebral pulse parameters measured using optical imaging can quantify changes in cerebral vascular tone, both globally and locally. In experiment 1, 51 older adults (age range=55-87) performed a voluntary breath-holding task while cerebral pulse amplitude measures were taken. We found significant pulse amplitude variations across breath-holding periods, indicating vasodilation during, and vasoconstriction after breath holding. The breath-holding index (BHI), a measure of cerebrovascular reactivity (CVR) was derived and found to correlate with age. BHI was also correlated with performance in the Modified Mini-Mental Status Examination, even after controlling for age and education. In experiment 2, the same participants performed a Sternberg task, and changes in regional pulse amplitude between high (set-size 6) and low (set-size 2) task loads were compared. Only task-related areas in the fronto-parietal network (FPN) showed significant reduction in pulse amplitude, indicating vasodilation. Non-task-related areas such as the somatosensory and auditory cortices did not show such reductions. Taken together, these experiments suggest that optical pulse parameters can index changes in brain vascular tone both globally and locally, using both physiological and cognitive load manipulations. PMID:27235126

  8. Ethylene and ammonia traces measurements from the patients' breath with renal failure via LPAS method

    NASA Astrophysics Data System (ADS)

    Popa, C.; Dutu, D. C. A.; Cernat, R.; Matei, C.; Bratu, A. M.; Banita, S.; Dumitras, D. C.

    2011-11-01

    The application of laser photoacoustic spectroscopy (LPAS) for fast and precise measurements of breath biomarkers has opened up new promises for monitoring and diagnostics in recent years, especially because breath test is a non-invasive method, safe, rapid and acceptable to patients. Our study involved assessment of breath ethylene and breath ammonia levels in patients with renal failure receiving haemodialysis (HD) treatment. Breath samples from healthy subjects and from patients with renal failure were collected using chemically inert aluminized bags and were subsequently analyzed using the LPAS technique. We have found out that the composition of exhaled breath in patients with renal failure contains not only ethylene, but also ammonia and gives valuable information for determining efficacy and endpoint of HD. Analysis of ethylene and ammonia traces from the human breath may provide insight into severity of oxidative stress and metabolic disturbances and may ensure optimal therapy and prevention of pathology at patients on continuous HD.

  9. Acoustic plethysmography measures breathing in unrestrained neonatal mice.

    PubMed

    Daubenspeck, J Andrew; Li, Aihua; Nattie, Eugene E

    2008-01-01

    Measurement of breathing volumes in neonatal mice is of growing importance in order to characterize the influence of development and genetic modifications on respiratory control to evaluate hypotheses concerned with human infant deficits that may affect sudden infant death syndrome, for example. Current techniques require undesirable physical constraints or incur possible artifacts specific to very small animals. We have examined the utility of a recently proposed approach using an acoustic resonance procedure that does not require undue physical constraint beyond placement in the acoustic plethysmograph. We show here that this approach can be applied to baby mice 5 days after birth and that it can be accurately calibrated. In addition, this approach should be useful to study unrestrained neonatal mice under conditions where body temperature approaches environmental temperature and barometric plethysmography cannot be used. PMID:17962574

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  12. Heart rate and blood pressure time courses during prolonged dry apnoea in breath-hold divers.

    PubMed

    Perini, Renza; Tironi, Adelaide; Gheza, Alberto; Butti, Ferdinando; Moia, Christian; Ferretti, Guido

    2008-09-01

    To define the dynamics of cardiovascular adjustments to apnoea, beat-to-beat heart rate (HR) and blood pressure and arterial oxygen saturation (SaO(2)) were recorded during prolonged breath-holding in air in 20 divers. Apnoea had a mean duration of 210 +/- 70 s. In all subjects, HR attained a value 14 beats min(-1) lower than control within the initial 30 s (phase I). HR did not change for the following 2-2.5 min (phase II). Then, nine subjects interrupted the apnoea (group A), whereas 11 subjects (group B) could prolong the breath-holding for about 100 s, during which HR continuously decreased (phase III). In both groups, mean blood pressure was 8 mmHg above control at the end of phase I; it then further increased by additional 12 mmHg at the end of the apnoea. In both groups, SaO(2) did not change in the initial 100-140 s of apnoea; then, it decreased to 95% at the end of phase II. In group B, SaO(2) further diminished to 84% at the end of phase III. A typical pattern of cardiovascular readjustments was identified during dry apnoea. This pattern was not compatible with a role for baroreflexes in phase I and phase II. Further readjustment in group B may imply a role for both baroreflexes and chemoreflexes. Hypothesis has been made that the end of phase II corresponds to physiological breakpoint. PMID:18496707

  13. What Controls Your Breathing?

    MedlinePlus

    ... To a limited degree, you can change your breathing rate, such as by breathing faster or holding your ... oxygen levels in your blood and change your breathing rate as needed. Sensors in the airways detect lung ...

  14. Rapid shallow breathing

    MedlinePlus

    Tachypnea; Breathing - rapid and shallow; Fast shallow breathing; Respiratory rate - rapid and shallow ... Shallow, rapid breathing has many possible medical causes, including: Asthma Blood clot in an artery in the lung Choking Chronic obstructive ...

  15. 77 FR 35747 - Highway Safety Programs; Conforming Products List of Evidential Breath Alcohol Measurement Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-14

    ...) published in the Federal Register on March 11, 2010 (75 FR 11624) for instruments that conform to the Model Specifications for Evidential Breath Alcohol Measurement Devices dated, September 17, 1993 (58 FR 48705). DATES... Alcohol (38 FR 30459). A Qualified Products List of Evidential Breath Measurement Devices comprised...

  16. 75 FR 11624 - Highway Safety Programs; Conforming Products List of Evidential Breath Alcohol Measurement Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-11

    ... Register on December 17, 2007 (72 FR 71480) for instruments that conform to the Model Specifications for Evidential Breath Alcohol Measurement Devices (58 FR 48705). DATES: Effective Date: March 11, 2010. FOR... Administration (NHTSA) published the Standards for Devices to Measure Breath Alcohol (38 FR 30459). A...

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

    PubMed

    Tancredi, Felipe B; Hoge, Richard D

    2013-07-01

    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

  18. Stable isotopes in breath, blood, feces and feathers can indicate intra-individual changes in the diet of migratory songbirds.

    PubMed

    Podlesak, David W; McWilliams, Scott R; Hatch, Kent A

    2005-02-01

    We used stable isotopes of C in breath, blood, feces and feathers to identify intra-individual changes in diet and the timescale of diet changes in free-living songbirds at a stopover site. Because accurate interpretation of differences between the delta13C of breath, plasma, and red blood cells (RBCs) relative to diet requires knowing the turnover rate of C within them, we determined the rate of change of C in breath, plasma and RBCs for yellow-rumped warblers (Dendroica coronata). Half-lives of C in breath, plasma, and RBCs were 4.4+/-2.1 h, 24.8+/-12.3 h and 10.9+/-3.2 days, respectively, for yellow-rumped warblers. delta13C of breath, plasma, RBCs and feces from wild-caught golden-crowned kinglets (Regulus satrapa), ruby-crowned kinglets (R. calendula) and gray catbirds (Dumetella carolinensis) indicated that they had maintained an isotopically consistent diet for an extended period of time. However, delta13C of breath and plasma indicated that white-throated sparrows (Zonotrichia albicollis) had recently expanded their diet to include a C4 dietary component. Likewise, delta13C of breath, plasma, RBCs and feces indicated that some wild-caught yellow-rumped warblers had consumed foods with a more enriched protein signature prior to their arrival on Block Island, and since arrival, they had consumed mostly northern bayberry (Myrica pensylvanica). Therefore, comparisons of the delta13C of breath, plasma, RBCs, feces and feathers from individual songbirds can indicate changes in diet and provide an estimate of the timescale of the diet change. PMID:15586297

  19. Individual breathing reactions measured in hemoglobin by hydrogen exchange methods

    SciTech Connect

    Englander, S.W.; Calhoun, D.B.; Englander, J.J.; Kallenbach, N.R.; Liem, R.K.H.; Malin, E.L.; Mandal, C.; Rogero, J.R.

    1980-10-01

    Protein hydrogen exchange is generally believed to register some aspect of internal protein dynamics, but the kind of motion at work is not clear. Experiments are being done to identify the determinants of protein hydrogen exchange and to distinguish between local unfolding and accessibility-penetration mechanisms. Results with small molecules, polynucleotides, and proteins demonstrate that solvent accessibility is by no means sufficient for fast exchange. H-exchange slowing is quite generally connected with intramolecular H-bonding, and the exchange process depends pivotally on transient H-bond cleavage. At least in ..cap alpha..-helical structures, the cooperative aspect of H-bond cleavage mut be expressed in local unfolding reactions. Results obtained by use of a difference hydrogen exchange method appear to provide a direct measurement of transient, cooperative, local unfolding reactions in hemoglobin. The reality of these supposed coherent breathing units is being tested by using the difference H-exchange approach to tritium label the units one at a time and then attempting to locate the tritium by fragmenting the protein, separating the fragments, and testing them for label. Early results demonstrate the feasibility of this approach.

  20. Evaluation of Candidate Measures for Home-Based Screening of Sleep Disordered Breathing in Taiwanese Bus Drivers

    PubMed Central

    Ting, Hua; Huang, Ren-Jing; Lai, Ching-Hsiang; Chang, Shen-Wen; Chung, Ai-Hui; Kuo, Teng-Yao; Chang, Ching-Haur; Shih, Tung-Sheng; Lee, Shin-Da

    2014-01-01

    Background: Sleepiness-at-the-wheel has been identified as a major cause of highway accidents. The aim of our study is identifying the candidate measures for home-based screening of sleep disordered breathing in Taiwanese bus drivers, instead of polysomnography. Methods: Overnight polysomnography accompanied with simultaneous measurements of alternative screening devices (pulse oximetry, ApneaLink, and Actigraphy), heart rate variability, wake-up systolic blood pressure and questionnaires were completed by 151 eligible participants who were long-haul bus drivers with a duty period of more than 12 h a day and duty shifting. Results: 63.6% of professional bus drivers were diagnosed as having sleep disordered breathing and had a higher body mass index, neck circumference, systolic blood pressure, arousal index and desaturation index than those professional bus drivers without evidence of sleep disordered breathing. Simple home-based candidate measures: (1) Pulse oximetry, oxygen-desaturation indices by ≥3% and 4% (r = 0.87∼0.92); (2) Pulse oximetry, pulse-rising indices by ≥7% and 8% from a baseline (r = 0.61∼0.89); and (3) ApneaLink airflow detection, apnea-hypopnea indices (r = 0.70∼0.70), based on recording-time or Actigraphy-corrected total sleep time were all significantly correlated with, and had high agreement with, corresponding polysomnographic apnea-hypopnea indices [(1) 94.5%∼96.6%, (2) 93.8%∼97.2%, (3) 91.1%∼91.3%, respectively]. Conversely, no validities of SDB screening were found in the multi-variables apnea prediction questionnaire, Epworth Sleepiness Scale, night-sleep heart rate variability, wake-up systolic blood pressure and anthropometric variables. Conclusions: The indices of pulse oximetry and apnea flow detection are eligible criteria for home-based screening of sleep disordered breathing, specifically for professional drivers. PMID:24803198

  1. MEASUREMENTS OF AIR POLLUTANT BIOMARKERS WITH EXHALED BREATH TECHNIQUES

    EPA Science Inventory

    Use of exhaled breath condensate (EBC) has appeal as a noninvasive surrogate sample for lung-derived fluid. Additionally, EBC can be collected multiple times over the course of a study, unlike many other lung sampling techniques which can be performed fewer times. However validat...

  2. Endovascular blood flow measurement system

    NASA Astrophysics Data System (ADS)

    Khe, A. K.; Cherevko, A. A.; Chupakhin, A. P.; Krivoshapkin, A. L.; Orlov, K. Yu

    2016-06-01

    In this paper an endovascular measurement system used for intraoperative cerebral blood flow monitoring is described. The system is based on a Volcano ComboMap Pressure and Flow System extended with analogue-to-digital converter and PC laptop. A series of measurements performed in patients with cerebrovascular pathologies allows us to introduce “velocity-pressure” and “flow rate-energy flow rate” diagrams as important characteristics of the blood flow. The measurement system presented here can be used as an additional instrument in neurosurgery for assessment and monitoring of the operation procedure. Clinical data obtained with the system are used for construction of mathematical models and patient-specific simulations. The monitoring of the blood flow parameters during endovascular interventions was approved by the Ethics Committee at the Meshalkin Novosibirsk Research Institute of Circulation Pathology and included in certain surgical protocols for pre-, intra- and postoperative examinations.

  3. Metabolic analyzer. [for measuring metabolic rate and breathing dynamics of human beings

    NASA Technical Reports Server (NTRS)

    Rummel, J. A.; Perry, C. L. (Inventor)

    1974-01-01

    An apparatus is described for the measurement of metabolic rate and breathing dynamics in which inhaled and exhaled breath are sensed by sealed, piston-displacement type spirometers. These spirometers electrically measure the volume of inhaled and exhaled breath. A mass spectrometer analyzes simultaneously for oxygen, carbon dioxide, nitrogen and water vapor. Computation circuits are responsive to the outputs of the spirometers, mass spectrometer, temperature, pressure and timing signals and compute oxygen consumption, carbon dioxide production, minute volume and respiratory exchange ratio. A selective indicator provides for read-out of these data at predetermined cyclic intervals.

  4. Sleep-Disordered Breathing and 24-Hour Blood Pressure Pattern Among Older Adults

    PubMed Central

    White, William B.; Kutner, Michael; Ouslander, Joseph G.; Bliwise, Donald L.

    2009-01-01

    Background To examine the association between sleep-disordered breathing (SDB) and 24-hour blood pressure (BP) pattern among community-dwelling older adults. Methods A convenience sample of 70 community-dwelling older adults, recruited from senior housing, community centers, and learning centers, were admitted to General Clinical Research Center, Emory University Hospital, Atlanta, Ga. Information regarding demographic and clinical history was obtained using questionnaires. Twenty-four–hour BP monitoring in supine position was performed using Spacelabs model 20207. Breathing during sleep was monitored with the use of a modified sleep recording system (Embletta, PDS), which monitors nasal and oral airflow, chest and abdominal movements, and pulse oximetry. Night time–daytime (night-day) BP ratio (average night-time BP divided by daytime BP) was calculated both for systolic and diastolic BPs. Results Sixty-nine participants, mean age 74.9 ± 6.4 years (41 [57%] women), completed the study. The mean apnea-hypopnea index (AHI) was 13 ± 13 per hour of sleep, and 20 participants (29%) had AHI ≥15 per hour of sleep, indicating moderate to severe SDB. Moderate to severe SDB (AHI ≥15 per hour of sleep) was significantly associated with nocturnal hypertension, whereas there was no statistically significant difference in wake-time BP between those with and without moderate to severe SDB. Stepwise multiple regressions showed that AHI independently predicted increased night-day systolic and night-day diastolic BP ratio, even after controlling for nocturia frequency. Conclusions The results indicate increased BP load associated with increased AHI in this group of older adults. This increased BP load may contribute to increased hypertension-related morbidity and disease burden. PMID:19196901

  5. Measurement of retinal blood velocity

    NASA Astrophysics Data System (ADS)

    Winchester, Leonard W., Jr.; Chou, Nee-Yin

    2006-02-01

    A fundus camera was modified to illuminate the retina of a rabbit model with low power laser light in order to obtain laser speckle images. A fast-exposure charge-coupled device (CCD) camera was used to capture laser speckle images of the retina. Image acquisition was synchronized with the arterial pulses of the rabbit to ensure that all images are obtained at the same point in the cardiac cycle. The rabbits were sedated and a speculum was inserted to prevent the eyelid from closing. Both albino (New Zealand; pigmented (Dutch belted) rabbits were used in the study. The rabbit retina is almost avascular. The measurements are obtained for choroidal tissue as well as retinal tissue. Because the retina is in a region of high metabolism, blood velocity is strongly affected by blood oxygen saturation. Measurements of blood velocity obtained over a wide range of O II saturations (58%-100%) showed that blood velocity increases with decreasing O II saturation. For most experiments, the left eye of the rabbit was used for laser measurements whereas the right eye served as a control. No observable difference between pre- and post-experimented eye was noted. Histological examinations of retinal tissue subjected to repeated laser measurements showed no indication of tissue damage.

  6. [*C]octanoic acid breath test to measure gastric emptying rate of solids.

    PubMed

    Maes, B D; Ghoos, Y F; Rutgeerts, P J; Hiele, M I; Geypens, B; Vantrappen, G

    1994-12-01

    We have developed a breath test to measure solid gastric emptying using a standardized scrambled egg test meal (250 kcal) labeled with [14C]octanoic acid or [13C]octanoic acid. In vitro incubation studies showed that octanoic acid is a reliable marker of the solid phase. The breath test was validated in 36 subjects by simultaneous radioscintigraphic and breath test measurements. Nine healthy volunteers were studied after intravenous administration of 200 mg erythromycin and peroral administration of 30 mg propantheline, respectively. Erythromycin significantly enhanced gastric emptying, while propantheline significantly reduced gastric emptying rates. We conclude that the [*C]octanoic breath test is a promising and reliable test for measuring the gastric emptying rate of solids. PMID:7995200

  7. CONTROLLED METHYL TERTIARY BUTYL ETHER (MTBE) EXPOSURE TO HUMANS THROUGH DERMAL, INGESTION, AND INHALATION ROUTES AND THE RESULTANT BIOMARKER TERTIARY BUTYL ALCOHOL (TBA) AS MEASURED IN EXHALED BREATH AND VENOUS BLOOD

    EPA Science Inventory

    Radiocarbon (14C) measurements provide an estimate of the fraction of carbon in a sample that is biogenic. In September 1997 during SCOS97 a series of 3-h canister samples of ambient air were collected at the Azusa air monitoring station during morning and afternoon periods. ...

  8. Measurement of low breath-alcohol concentrations: laboratory studies and field experience.

    PubMed

    Dubowski, K M; Essary, N A

    1999-10-01

    Recent federal rules and traffic law changes impose breath-alcohol thresholds of 0.02 and 0.04 g/210 L upon some classes of motor vehicle operators, such as juveniles and commercial vehicle operators. In federally regulated alcohol testing in the workplace, removal of covered workers from safety-sensitive duties, and other adverse actions, also occur at breath-alcohol concentrations (BrACs) of 0.02 and 0.04 g/210 L. We therefore studied performance of vapor-alcohol and breath-alcohol measurement at low alcohol concentrations in the laboratory and in the field, with current-generation evidential analyzers. We report here chiefly our field experience with evidential breath-alcohol testing of drinking drivers on paired breath samples using 62 Intoxilyzer 5000-D analyzers, for BrACs of 0-0.059 g/210 L. The data from 62 law enforcement breath-alcohol testing sites were collected and pooled, with BrACs recorded to three decimal places, and otherwise carried out under the standard Oklahoma evidential breath-alcohol testing protocol. For 2105 pooled simulator control tests at 0.06-0.13 g/210 L the mean +/- SD of the differences between target and result were -0.001 +/- 0.0035 g/210 L and 0.003 +/- 0.0023 g/210 L for signed and absolute differences, respectively (spans -0.016-0.010, 0.000-0.016). For 2078 paired duplicate breath-alcohol measurements with the Intoxilyzer 5000-D, the mean +/- SD difference (BrAC1-BrAC2) were 0.002 +/- 0.0026 (span 0-0.020 g/210 L). Variability of breath-alcohol measurements was related inversely to the alcohol concentration. Ninety-nine percent prediction limits for paired BrAC measurements correspond to a 0.020 g/210 L maximum absolute difference, meeting the NSC/CAOD recommendation that paired breath-alcohol analysis results within 0.02 g/210 L shall be deemed to be in acceptable agreement. We conclude that the field system for breath-alcohol analysis studied by us can and does perform reliably and accurately at low BrACs. PMID:10517542

  9. Laser 3-D measuring system and real-time visual feedback for teaching and correcting breathing

    NASA Astrophysics Data System (ADS)

    Povšič, Klemen; Fležar, Matjaž; Možina, Janez; Jezeršek, Matija

    2012-03-01

    We present a novel method for real-time 3-D body-shape measurement during breathing based on the laser multiple-line triangulation principle. The laser projector illuminates the measured surface with a pattern of 33 equally inclined light planes. Simultaneously, the camera records the distorted light pattern from a different viewpoint. The acquired images are transferred to a personal computer, where the 3-D surface reconstruction, shape analysis, and display are performed in real time. The measured surface displacements are displayed with a color palette, which enables visual feedback to the patient while breathing is being taught. The measuring range is approximately 400×600×500 mm in width, height, and depth, respectively, and the accuracy of the calibrated apparatus is +/-0.7 mm. The system was evaluated by means of its capability to distinguish between different breathing patterns. The accuracy of the measured volumes of chest-wall deformation during breathing was verified using standard methods of volume measurements. The results show that the presented 3-D measuring system with visual feedback has great potential as a diagnostic and training assistance tool when monitoring and evaluating the breathing pattern, because it offers a simple and effective method of graphical communication with the patient.

  10. Elimination kinetics of volatile organics in humans using breath measurements

    SciTech Connect

    Pellizzari, E.D.; Wallace, L.A.; Gordon, S.M. )

    1992-07-01

    During the past decade significant strides have been made toward understanding the sources and factors which lead to volatile organic chemical (VOC) exposure in the general population. Less is known, however, about the impact of low-level environmental exposure on human health. Investigations are underway in a number of laboratories in an effort to determine the uptake, distribution, metabolism, and elimination kinetics for VOCs in humans. We examined the elimination kinetics for the third phase for ten VOCs--1,1,-trichloroethane, trichloroethylene, tetrachloroethylene, benzene, toluene, m,p-xylenes, o-xylene, ethylbenzene, p-dichlorobenzene, and limonene--in human subjects. Subjects were exposed to a variety of common consumer products and breath samples were collected post-exposure while the subjects spent up to 10 hr in a clean air environment. VOCs from breath samples were collected into canisters or onto Tenax GC cartridges and analyzed by gas chromatography-mass spectrometry. Exponential modeling of the decay data was performed to obtain kinetic parameters. The half-lives for trichloroethylene and 1,1,1-trichloroethane were approximately 5 to 8 hr for the four subjects. In general, the magnitude and range of variability was larger for toluene, limonene, and p-dichlorobenzene than for the other VOCs; the elimination rate spanning a few hours to a day or two. Thus, VOCs exhibit relatively short residence times in the body relative to other halo-carbons, such as polychlorinated biphenyls and dioxins.

  11. Dirhythmic breathing.

    PubMed

    Flemister, G; Goldberg, N B; Sharp, J T

    1981-01-01

    Four patients with severe chronic obstructive lung disease and recent respiratory failure are described in whom two distinct simultaneous respiratory rhythms were identified, one at 8 to 13 breaths per minute and the other at 39 to 65 per minute. Magnetometer measurements of thoracoabdominal motion together with simultaneous electromyograms of multiple inspiratory muscles suggested that both rhythms were the result of coordinated action of several inspiratory muscles. We suggest that this phenomenon, which we have called dirhythmic breathing, results from the conflicting influence upon respiratory centers and motoneurons of two or more stimuli, some favoring rapid shallow breaths and others slow deep breaths. PMID:7449504

  12. Application of Novel Method to Measure Endogenous VOCs in Exhaled Breath Condensate Before and After Exposure to Diesel Exhaust

    EPA Science Inventory

    Polar volatile organic compounds (PVOCs) such as aldehydes, ketones, and alcohols are byproducts of normal human metabolism and are present in exhaled breath and blood. Environmental exposures, individual activities, and disease states can perturb normal metabolic processes and ...

  13. [Peculiarities of respiration mechanics in spontaneously breathing newborn infants. 1. Principles of the measurement technics].

    PubMed

    Wauer, R R; Schmalisch, G

    1983-01-01

    Disturbances of breathing mechanics may involve disturbances of ventilation as one cause of hypoxaemia. The qualitative and quantitative analysis of breathing mechanics has several diagnostical and therapeutical advantages, but their application in newborns, under conditions of spontaneous ventilation, is rendered more difficult by the missing co-operation of the newborns and by the missing of suitable measurement devices for a bedside measurement. The determination of parameters of breathing mechanics is based on the measurement of breathing flow rate (V), tidal volume (VT) and esophageal pressure (Pe). Bodyplethysmographs, face masks and nasal prongs can be used for the measurement of V and VT, however, face masks have the most methodological and technical advantages for the bedside application, moreover, they guarantee a very low injury of newborns. Until now the fluid-filled open catheter is used most frequently for the measurement of esophageal pressure, however, it will be replaced in future by the microtip pressure transducer (Tip-catheter), which offers fundamental advantages. In addition to these technical problems the complete clinical application of breathing mechanical investigations is rendered more difficult, because the standardization of the investigative conditions, the parameters and the proposals on evaluation techniques are absent until now. PMID:6670321

  14. A mind you can count on: validating breath counting as a behavioral measure of mindfulness

    PubMed Central

    Levinson, Daniel B.; Stoll, Eli L.; Kindy, Sonam D.; Merry, Hillary L.; Davidson, Richard J.

    2014-01-01

    Mindfulness practice of present moment awareness promises many benefits, but has eluded rigorous behavioral measurement. To date, research has relied on self-reported mindfulness or heterogeneous mindfulness trainings to infer skillful mindfulness practice and its effects. In four independent studies with over 400 total participants, we present the first construct validation of a behavioral measure of mindfulness, breath counting. We found it was reliable, correlated with self-reported mindfulness, differentiated long-term meditators from age-matched controls, and was distinct from sustained attention and working memory measures. In addition, we employed breath counting to test the nomological network of mindfulness. As theorized, we found skill in breath counting associated with more meta-awareness, less mind wandering, better mood, and greater non-attachment (i.e., less attentional capture by distractors formerly paired with reward). We also found in a randomized online training study that 4 weeks of breath counting training improved mindfulness and decreased mind wandering relative to working memory training and no training controls. Together, these findings provide the first evidence for breath counting as a behavioral measure of mindfulness. PMID:25386148

  15. Measurement of Whole-Body CO2 Production in Birds Using Real-Time Laser-Derived Measurements of Hydrogen (δ(2)H) and Oxygen (δ(18)O) Isotope Concentrations in Water Vapor from Breath.

    PubMed

    Mitchell, G W; Guglielmo, C G; Hobson, K A

    2015-01-01

    The doubly labeled water (DLW) method is commonly used to measure energy expenditure in free-living wildlife and humans. However, DLW studies involving animals typically require three blood samples, which can affect behavior and well-being. Moreover, measurement of H (δ(2)H) and O (δ(18)O) isotope concentrations in H2O derived from blood using conventional isotope ratio mass spectrometry is technically demanding, time-consuming, and often expensive. A novel technique that would avoid these constraints is the real-time measurement of δ(2)H and δ(18)O in the H2O vapor of exhaled breath using cavity ring-down (CRD) spectrometry, provided that δ(2)H and δ(18)O from body H2O and breath were well correlated. Here, we conducted a validation study with CRD spectrometry involving five zebra finches (Taeniopygia guttata), five brown-headed cowbirds (Molothrus ater), and five European starlings (Sturnus vulgaris), where we compared δ(2)H, δ(18)O, and rCO2 (rate of CO2 production) estimates from breath with those from blood. Isotope concentrations from blood were validated by comparing dilution-space estimates with measurements of total body water (TBW) obtained from quantitative magnetic resonance. Isotope dilution-space estimates from δ(2)H and δ(18)O values in the blood were similar to and strongly correlated with TBW measurements (R(2) = 0.99). The (2)H and (18)O (ppm) in breath and blood were also highly correlated (R(2) = 0.99 and 0.98, respectively); however, isotope concentrations in breath were always less enriched than those in blood and slightly higher than expected, given assumed fractionation values between blood and breath. Overall, rCO2 measurements from breath were strongly correlated with those from the blood (R(2) = 0.90). We suggest that this technique will find wide application in studies of animal and human energetics in the field and laboratory. We also provide suggestions for ways this technique could be further improved. PMID:26658408

  16. Environmental and occupational exposure to benzene by analysis of breath and blood.

    PubMed

    Perbellini, L; Faccini, G B; Pasini, F; Cazzoli, F; Pistoia, S; Rosellini, R; Valsecchi, M; Brugnone, F

    1988-05-01

    Benzene exposure of chemical workers was studied, during the entire workshift, by continuous monitoring of workplace benzene concentration, and 16 hours after the end of the workshift by the measurement of alveolar and blood benzene concentrations and excretion of urinary phenol. Exposure of hospital staff was studied by measuring benzene concentrations in the alveolar and blood samples collected during the hospital workshift. Instantaneous environmental air samples were also collected, at the moment of the biological sampling, for all the subjects tested. A group of 34 chemical workers showed an eight hour exposure to benzene, as a geometric mean, of 1.12 micrograms/l which corresponded, 16 hours after the end of the workshift, to a geometric mean benzene concentration of 70 ng/l in the alveolar air and 597 ng/l in the blood. Another group of 27 chemical workers (group A) turned out to be exposed to an indeterminable eight hour exposure to benzene that corresponded, the morning after, to a geometric mean benzene concentration of 28 ng/l in the alveolar air and 256 ng/l in the blood. The group of hospital staff (group B) had a benzene concentration of 14 ng/l in the alveolar air and 269 ng/l in the blood. Instantaneous environmental samples showed that in the infirmaries the geometric mean benzene concentration was 58 ng/l during the examination of the 34 chemical workers, 36 ng/l during the examination of the 27 chemical workers (group A), and 5 ng/l during the examination of the 19 subjects of the hospital staff (group B). Statistical analysis showed that the alveolar and blood benzene concentrations in the 34 workers exposed to 1.12 microgram/l of benzene differed significantly from those in groups A and B. It was found, moreover, that the alveolar and blood benzene concentrations were higher in the smokers in groups A and B but not in the smokers in the group of 34 chemical workers. The slope of the linear correlation between the alveolar and the instantaneous

  17. Automatic blood pressure measuring system (M092)

    NASA Technical Reports Server (NTRS)

    Nolte, R. W.

    1977-01-01

    The Blood Pressure Measuring System is described. It measures blood pressure by the noninvasive Korotkoff sound technique on a continual basis as physical stress is imposed during experiment M092, Lower Body Negative Pressure, and experiment M171, Metabolic Activity.

  18. 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. PMID:24211983

  19. MEASUREMENT OF THE BIOTRANSFER AND TIME CONSTANT OF RADON FROM INGESTED WATER BY HUMAN BREATH ANALYSIS

    EPA Science Inventory

    Forty-one tests were performed on 38 volunteers to measure elimination rates of 222Rn in expired breath. articipants ranged from ages 9 to 85 y, with 16 males and 22 females. he levels of physical activity of the subjects ranged from very inactive to marathon level. alibration of...

  20. How many digits should be reported in forensic breath alcohol measurements?

    PubMed

    Gullberg, Rod G

    2015-06-01

    Uncertainty is an inherent property of all measurements. The magnitude of this uncertainty will determine the number of meaningful digits that should be reported in a measurement result. Several statistical arguments are considered providing evidence that three digit truncated results are more appropriate than two since the first significant digit of the combined uncertainty (standard deviation) in breath alcohol measurement is found in the third decimal place. Probably, the most compelling reason for reporting three digits is the significant reduction in combined uncertainty compared with the use of two digits. For a breath alcohol concentration of 0.089 g/210 L, the combined uncertainty for two digit results is ∼0.0042 g/210 L, compared with 0.0031 g/210 L for three digit results. The historical practice of reporting two digit truncated results in forensic breath alcohol analysis has been largely based on the use of analog scale instruments with 0.01 g/210 L scale resolution. With today's modern digital instrumentation, this practice should be reconsidered. While the focus of this paper is on breath alcohol analysis, the general principles will apply to any quantitative analytical measurement. PMID:25829470

  1. Cuff for Blood-Vessel Pressure Measurements

    NASA Technical Reports Server (NTRS)

    Shimizu, M.

    1982-01-01

    Pressure within blood vessel is measured by new cufflike device without penetration of vessel. Device continuously monitors blood pressure for up to 6 months or longer without harming vessel. Is especially useful for vessels smaller than 4 or 5 millimeters in diameter. Invasive methods damage vessel wall, disturb blood flow, and cause clotting. They do not always give reliable pressure measurements over prolonged periods.

  2. The association of annual air pollution exposure with blood pressure among patients with sleep-disordered breathing.

    PubMed

    Liu, Wen-Te; Lee, Kang-Yun; Lee, Hsin-Chien; Chuang, Hsiao-Chi; Wu, Dean; Juang, Jer-Nan; Chuang, Kai-Jen

    2016-02-01

    While sleep-disordered breathing (SDB), high blood pressure (BP) and air pollution exposure have separately been associated with increased risk of cardiopulmonary mortality, the association linking air pollution exposure to BP among patients with sleep-disordered breathing is still unclear. We collected 3762 participants' data from the Taipei Medical University Hospital's Sleep Center and air pollution data from the Taiwan Environmental Protection Administration. Associations of 1-year mean criteria air pollutants [particulate matter with aerodynamic diameters ≤10 μm (PM10), particulate matter with aerodynamic diameters ≤2.5 μm (PM2.5), nitrogen dioxide (NO2) and ozone (O3)] with systolic BP (SBP) and diastolic BP (DBP) were investigated by generalized additive models. After controlling for age, sex, body mass index (BMI), temperature and relative humidity, we observed that increases in air pollution levels were associated with decreased SBP and increased DBP. We also found that patients with apnea-hypopnea index (AHI) ≥30 showed a stronger BP response to increased levels of air pollution exposure than those with AHI<30. Stronger effects of air pollution exposure on BP were found in overweight participants than in participants with normal BMI. We concluded that annual exposure to air pollution was associated with change of BP among patients with sleep-disordered breathing. The association between annual air pollution exposure and BP could be modified by AHI and BMI. PMID:26580727

  3. Modelling acute renal failure using blood and breath biomarkers in rats.

    PubMed

    Moorhead, Katherine T; Hill, Jonathan V; Chase, J Geoffrey; Hann, Christopher E; Scotter, Jennifer M; Storer, Malina K; Endre, Zoltan H

    2011-02-01

    This paper compares three methods for estimating renal function, as tested in rats. Acute renal failure (ARF) was induced via a 60-min bilateral renal artery clamp in 8 Sprague-Dawley rats and renal function was monitored for 1 week post-surgery. A two-compartment model was developed for estimating glomerular filtration via a bolus injection of a radio-labelled inulin tracer, and was compared with an estimated creatinine clearance method, modified using the Cockcroft-Gault equation for rats. These two methods were compared with selected ion flow tube-mass spectrometry (SIFT-MS) monitoring of breath analytes. Determination of renal function via SIFT-MS is desirable since results are available non-invasively and in real time. Relative decreases in renal function show very good correlation between all 3 methods (R²=0.84, 0.91 and 0.72 for breath-inulin, inulin-creatinine, and breath-creatinine correlations, respectively), and indicate good promise for fast, non-invasive determination of renal function via breath testing. PMID:20728235

  4. Reassessment of chemical control of breathing in undisturbed bullfrogs, Lithobates catesbeianus, using measurements of pulmonary ventilation.

    PubMed

    Santin, Joseph M; Hartzler, Lynn K

    2016-04-01

    Despite the importance of bullfrogs (Lithobates catesbeianus) as models in respiratory control, chemical control of breathing in conscious bullfrogs has never been assessed with methods that measure the tidal volume (VT). This has precluded the calculation of important respiratory variables like minute ventilation (V.E) and air convection requirement. To address this, we adapted airflow pneumotachography for use in bullfrogs and reassessed chemical control of breathing. We show that V.E measured with pneumotachography produces breathing pattern and metabolism values consistent with anurans. Second, we confirm that bullfrogs have small ventilatory responses to hypercarbia that include increases in tidal volume and a post-hypercarbic hyperpnea. We observed that the magnitude of the post-hypercarbic hyperpnea does not depend on ventilatory responses during hypercarbia. Finally, we showed that increases in breathing frequency and VT during hypoxia are differentially regulated with time. These findings comprise the first complete assessment of hypercarbic and hypoxic V.E responses in intact bullfrogs and emphasize the importance of measuring VT. PMID:26478178

  5. Accuracy of the blood pressure measurement.

    PubMed

    Rabbia, F; Del Colle, S; Testa, E; Naso, D; Veglio, F

    2006-08-01

    Blood pressure measurement is the cornerstone for the diagnosis, the treatment and the research on arterial hypertension, and all of the decisions about one of these single aspects may be dramatically influenced by the accuracy of the measurement. Over the past 20 years or so, the accuracy of the conventional Riva-Rocci/Korotkoff technique of blood pressure measurement has been questioned and efforts have been made to improve the technique with automated devices. In the same period, recognition of the phenomenon of white coat hypertension, whereby some individuals with an apparent increase in blood pressure have normal, or reduced, blood pressures when measurement is repeated away from the medical environment, has focused attention on methods of measurement that provide profiles of blood pressure behavior rather than relying on isolated measurements under circumstances that may in themselves influence the level of blood pressure recorded. These methodologies have included repeated measurements of blood pressure using the traditional technique, self-measurement of blood pressure in the home or work place, and ambulatory blood pressure measurement using innovative automated devices. The purpose of this review to serve as a source of practical information about the commonly used methods for blood pressure measurement: the traditional Riva-Rocci method and the automated methods. PMID:17016412

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

    PubMed

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

    2015-09-01

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

  7. H2S concentrations in the arterial blood during H2S administration in relation to its toxicity and effects on breathing

    PubMed Central

    Klingerman, Candice M.; Trushin, Neil; Prokopczyk, Bogdan

    2013-01-01

    Our aim was to establish in spontaneously breathing urethane-anesthetized rats, the relationship between the concentrations of H2S transported in the blood and the corresponding clinical manifestations, i.e., breathing stimulation and inhibition, during and following infusion of NaHS at increasing rates. The gaseous concentration of H2S (CgH2S, one-third of the total soluble form) was computed from the continuous determination of H2S partial pressure in the alveolar gas, while H2S, both dissolved and combined to hemoglobin, was measured at specific time points by sulfide complexation with monobromobimane (CMBBH2S). We found that using a potent reducing agent in vitro, H2S added to the whole blood had little interaction with the plasma proteins, as sulfide appeared to be primarily combined and then oxidized by hemoglobin. In vivo, H2S was undetectable in the blood in its soluble form in baseline conditions, while CMBBH2S averaged 0.7 ± 0.5 μM. During NaHS infusion, H2S was primarily present in nonsoluble form in the arterial blood: CMBBH2S was about 50 times higher than CgH2S at the lowest levels of exposure and 5 or 6 times at the levels wherein fatal apnea occurred. CgH2S averaged only 1.1 ± 0.7 μM when breathing increased, corresponding to a CMBBH2S of 11.1 ± 5.4 μM. Apnea occurred at CgH2S above 5.1 μM and CMBBH2S above 25.4 μM. At the cessation of exposure, CMBBH2S remained elevated, at about 3 times above baseline for at least 15 min. These data provide a frame of reference for studying the putative effects of endogenous H2S and for testing antidotes against its deadly effects. PMID:23904109

  8. The impact of breathing on HRV measurements: implications for the longitudinal follow-up of athletes.

    PubMed

    Saboul, Damien; Pialoux, Vincent; Hautier, Christophe

    2013-01-01

    The purpose of the present work was to compare daily variations of heart rate variability (HRV) parameters between controlled breathing (CB) and spontaneous breathing (SB) sessions during a longitudinal follow-up of athletes. HRV measurements were performed daily on 10 healthy male runners for 21 consecutive days. The signals were recorded during two successive randomised 5-minutes sessions. One session was performed in CB and the other in SB. The results showed significant differences between the two respiration methods in the temporal, nonlinear and frequency domains. However, significant correlations were observed between CB and SB (higher than 0.70 for RMSSD and SD1), demonstrating that during a longitudinal follow-up, these markers provide the same HRV variations regardless of breathing pattern. By contrast, independent day-to-day variations were observed with HF and LF/HF frequency markers, indicating no significant relationship between SB and CB data over time. Therefore, we consider that SB and CB may be used for HRV longitudinal follow-ups only for temporal and nonlinear markers. Indeed, the same daily increases and decreases were observed whatever the breathing method employed. Conversely, frequency markers did not provide the same variations between SB and CB and we propose that these indicators are not reliable enough to be used for day-to-day HRV monitoring. PMID:24050471

  9. Indirect Blood Pressure Measuring Device

    NASA Technical Reports Server (NTRS)

    Hum, L.; Cole, C. E.

    1973-01-01

    Design and performance of a blood pressure recording device for pediatric use are reported. A strain gage transducer with a copper-beryllium strip as force sensing element is used to monitor skin movements and to convert them into electrical signals proportional to those displacements. Experimental tests with this device in recording of force developed above the left femoral artery of a dog accurately produced a blood pressure curve.

  10. Blood Pressure Measurements Taken by Patients are Similar to Home and Ambulatory Blood Pressure Measurements

    PubMed Central

    Pierin, Angela M. G.; Ignez, Edna C.; Filho, Wilson Jacob; Barbato, Alfonso Júlio Guedes; Mion, Décio

    2008-01-01

    OBJECTIVE To compare blood pressure measurements taken at home by physicians, nurses, and patients with office blood pressure measurement , ambulatory blood pressure monitoring and home blood pressure measurement. METHODS A total of 44 patients seen by a home care program were studied. Protocol 1 a) blood pressure was measured by the patient, a physician and a nurse during a regular home visit (Home1); b) home blood pressure measurement was measured for 4 days (HBPM1); c) office blood pressure measurement was measured by a physician, a nurse, and the patient; and by 24-hour ambulatory blood pressure monitoring. Protocol 2 blood pressure was measured by the patient, a physician, and a nurse during a special home visit in the presence of a physician and a nurse only (Home2); and b) home blood pressure measurement was taken for the second time (HBPM2). Echocardiography, guided by a two-dimensional echocardiograph, was performed. RESULTS Protocol 1: a) office blood pressure measurement and Home1 were significantly higher than ambulatory blood pressure monitoring, except for systolic and diastolic office blood pressure measurement taken by the patient or a family member, systolic blood pressure taken by a nurse, and diastolic blood pressure taken by a physician. b) ambulatory blood pressure monitoring and HBPM1 were similar. Protocol 2: a) HBPM2 and Home2 were similar. b) Home2 was significantly lower than Home1, except for diastolic blood pressure taken by a nurse or the patient. There were significant relationships between: a) diastolic blood pressure measured by the patient and the thickness of the interventricular septum, posterior wall, and left ventricular mass; and b) ambulatory and HBPM2 diastolic and systolic blood pressure taken by a physician (home2) and left ventricular mass. Therefore, the data indicate that home blood pressure measurement and ambulatory blood pressure monitoring had good prognostic values relative to “office measurement.” CONCLUSION

  11. Breath holding duration as a measure of distress tolerance: examining its relation to measures of executive control.

    PubMed

    Sütterlin, Stefan; Schroijen, Mathias; Constantinou, Elena; Smets, Elyn; Van den Bergh, Omer; Van Diest, Ilse

    2013-01-01

    Recent research considers distress (in)tolerance as an essential component in the development of various forms of psychopathology. A behavioral task frequently used to assess distress tolerance is the breath holding task. Although breath holding time (BHT) has been associated with behavioral outcomes related to inhibitory control (e.g., smoking cessation), the relationship among breath holding and direct measures of executive control has not yet been thoroughly examined. The present study aims to assess (a) the BHT-task's test-retest reliability in a 1-year follow-up and (b) the relationship between a series of executive function tasks and breath holding duration. One hundred and thirteen students completed an initial BHT assessment, 58 of which also completed a series of executive function tasks [the Wisconsin Card Sorting Test (WCST), the Parametric Go/No-Go task and the N-back memory updating task]. A subsample of these students (N = 34) repeated the breath holding task in a second session 1 year later. Test-retest reliability of the BHT-task over a 1-year period was high (r = 0.67, p < 0.001), but none of the executive function tasks was significantly associated with BHT. The rather moderate levels of unpleasantness induced by breath holding in our sample may suggest that other processes (physiological, motivational) besides distress tolerance influence BHT. Overall, the current findings do not support the assumption of active inhibitory control in the BHT-task in a healthy sample. Our findings suggest that individual differences (e.g., in interoceptive or anxiety sensitivity) should be taken into account when examining the validity of BHT as a measure of distress tolerance. PMID:23908639

  12. Normal breathing pattern and arterial blood gases in awake and sleeping goats after near total destruction of the presumed pre-Bötzinger complex and the surrounding region

    PubMed Central

    Krause, K. L.; Forster, H. V.; Kiner, T.; Davis, S. E.; Bonis, J. M.; Qian, B.; Pan, L. G.

    2009-01-01

    Abrupt neurotoxic destruction of >70% of the pre-Bötzinger complex (preBötzC) in awake goats results in respiratory and cardiac failure (Wenninger JM, Pan LG, Klum L, Leekley T, Bastastic J, Hodges MR, Feroah TR, Davis S, Forster HV. J Appl Physiol 97: 1629–1636, 2004). However, in reduced preparations, rhythmic respiratory activity has been found in other areas of the brain stem (Huang Q, St. John WM. J Appl Physiol 64: 1405–1411, 1988; Janczewski WA, Feldman JL. J Physiol 570: 407–420, 2006; Lieske SP, Thoby-Brisson M, Telgkamo P, Ramierz JM. Nature Neurosci 3: 600–607, 2000; St. John WM, Bledsoe TA. J Appl Physiol 59: 684–690, 1985); thus we hypothesized that, when the preBötzC is destroyed incrementally over weeks, time-dependent plasticity within the respiratory network will result in a respiratory rhythm capable of maintaining normal blood gases. Microtubules were bilaterally implanted into the presumed preBötzC of seven goats. After recovery from surgery, studies were completed to establish baseline values for respiratory parameters. At weekly intervals, increasing volumes (in order 0.5, 1, 5, and 10 μl) of ibotenic acid (IA; 50 mM) were then injected into the preBötzC. All IA injections resulted in an acute tachypnea and dysrhythmia featuring augmented breaths, apneas, and increased breath-to-breath variation in breathing. In studies at night, apneas were nearly all central and occurred in the awake state. Breath-to-breath variation in breathing was greater (P < 0.05) during wakefulness than during non-rapid eye movement sleep. However, one week after the final IA injection, the breathing pattern, breath-to-breath variation, and arterial blood gases and pH were unchanged from baseline, but there was a 20% decrease in respiratory frequency (f) and CO2 sensitivity (P < 0.05), as well as a 40% decrease in the ventilatory response to hypoxia (P < 0.001). In subsequent histological analysis of the presumed preBötzC region of lesioned goats, it

  13. Breath air measurement using wide-band frequency tuning IR laser photo-acoustic spectroscopy

    NASA Astrophysics Data System (ADS)

    Kistenev, Yury V.; Borisov, Alexey V.; Kuzmin, Dmitry A.; Bulanova, Anna A.; Boyko, Andrey A.; Kostyukova, Nadezhda Y.; Karapuzikov, Alexey A.

    2016-03-01

    The results of measuring of biomarkers in breath air of patients with broncho-pulmonary diseases using wide-band frequency tuning IR laser photo-acoustic spectroscopy and the methods of data mining are presented. We will discuss experimental equipment and various methods of intellectual analysis of the experimental spectra in context of above task. The work was carried out with partial financial support of the FCPIR contract No 14.578.21.0082 (ID RFMEFI57814X0082).

  14. Free-Breathing 3D Whole Heart Black Blood Imaging with Motion Sensitized Driven Equilibrium

    PubMed Central

    Srinivasan, Subashini; Hu, Peng; Kissinger, Kraig V.; Goddu, Beth; Goepfert, Lois; Schmidt, Ehud J.; Kozerke, Sebastian; Nezafat, Reza

    2012-01-01

    Purpose To assess the efficacy and robustness of motion sensitized driven equilibrium (MSDE) for blood suppression in volumetric 3D whole heart cardiac MR. Materials and Methods To investigate the efficacy of MSDE on blood suppression and myocardial SNR loss on different imaging sequences. 7 healthy adult subjects were imaged using 3D ECG-triggered MSDE-prep T1-weighted turbo spin echo (TSE), and spoiled gradient echo (GRE), after optimization of MSDE parameters in a pilot study of 5 subjects. Imaging artifacts, myocardial and blood SNR were assessed. Subsequently, the feasibility of isotropic spatial resolution MSDE-prep black-blood was assessed in 6 subjects. Finally, 15 patients with known or suspected cardiovascular disease were recruited to be imaged using conventional multi-slice 2D DIR TSE imaging sequence and 3D MSDE-prep spoiled GRE. Results The MSDE-prep yields significant blood suppression (75-92%), enabling a volumetric 3D black-blood assessment of the whole heart with significantly improved visualization of the chamber walls. The MSDE-prep also allowed successful acquisition of black-blood images with isotropic spatial resolution. In the patient study, 3D black-blood MSDE-prep and DIR resulted in similar blood suppression in LV and RV walls but the MSDE prep had superior myocardial signal and wall sharpness. Conclusion MSDE-prep allows volumetric black-blood imaging of the heart. PMID:22517477

  15. Measuring Time-Averaged Blood Pressure

    NASA Technical Reports Server (NTRS)

    Rothman, Neil S.

    1988-01-01

    Device measures time-averaged component of absolute blood pressure in artery. Includes compliant cuff around artery and external monitoring unit. Ceramic construction in monitoring unit suppresses ebb and flow of pressure-transmitting fluid in sensor chamber. Transducer measures only static component of blood pressure.

  16. Shortness of Breath

    MedlinePlus

    ... deep breath, which usually results in retention of carbon dioxide and not enough oxygen in blood (obesity hypoventilation ... for anemia), and oximetry or blood oxygen or carbon dioxide levels. Your doctor also may obtain a chest ...

  17. Measurement of fat digestion in early life using a stable isotope breath test.

    PubMed Central

    McClean, P; Harding, M; Coward, W A; Green, M R; Weaver, L T

    1993-01-01

    13C breath tests are a safe, non-invasive way of assessing nutrient digestion and absorption that can be used repeatedly in infancy and childhood. The aim of this study was to assess their value for measuring fat digestion in infants and young children with cystic fibrosis, and healthy controls whose pancreatic exocrine function is immature, and to monitor pancreatic enzyme supplementation. Six infants with cystic fibrosis (aged 10-18 months) and nine healthy controls (aged 6-19 months) were studied. After an overnight fast each child ingested 7.5 mg/kg 13C trioctanoin (99 atom % excess) followed by a known volume of milk. Breath samples were collected before and at 30 minute intervals thereafter for five hours. The 13C enrichment of expired carbon dioxide was measured by gas isotope ratio mass spectrometry. The mean (SD) percentage dose recovery of 13C was 13.5 (5.3) for the cystic fibrosis group and 24.2 (6.7) for the healthy controls. When those with cystic fibrosis were studied after supplementary pancreatic enzymes, the mean percentage dose recovery rose to 17.1 (6.9). Total intraluminal lipolysis was diminished by 44% in young children with cystic fibrosis. Pancreatic enzyme supplements improved digestion by 27%. The 13C trioctanoin breath test was effective in detecting fat maldigestion and can be used to measure the benefits of enzyme supplements in early life. PMID:8215547

  18. Pancreatic islet blood flow and its measurement

    PubMed Central

    Jansson, Leif; Barbu, Andreea; Bodin, Birgitta; Drott, Carl Johan; Espes, Daniel; Gao, Xiang; Grapensparr, Liza; Källskog, Örjan; Lau, Joey; Liljebäck, Hanna; Palm, Fredrik; Quach, My; Sandberg, Monica; Strömberg, Victoria; Ullsten, Sara; Carlsson, Per-Ola

    2016-01-01

    Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting β-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future. PMID:27124642

  19. Pancreatic islet blood flow and its measurement.

    PubMed

    Jansson, Leif; Barbu, Andreea; Bodin, Birgitta; Drott, Carl Johan; Espes, Daniel; Gao, Xiang; Grapensparr, Liza; Källskog, Örjan; Lau, Joey; Liljebäck, Hanna; Palm, Fredrik; Quach, My; Sandberg, Monica; Strömberg, Victoria; Ullsten, Sara; Carlsson, Per-Ola

    2016-05-01

    Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting β-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future. PMID:27124642

  20. Automatic blood pressure measuring system (M091)

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The Leg Volume Measuring System is used to measure leg calf girth changes that occur during exposure to lower body negative pressure as a result of pooling of blood and other fluids in the lower extremities.

  1. Blood alcohol measurements in the emergency department: who needs them?

    PubMed Central

    Simel, D L; Feussner, J R

    1988-01-01

    We surveyed North Carolina emergency physicians to determine current medical practices regarding the use of blood alcohol concentrations using a hypothetical scenario. Most physicians (88 per cent) would not have obtained blood alcohol concentrations in a patient who had alcohol on his breath but was coherent and cooperative. For marginally impaired patients, more liberal use of blood alcohol concentrations and explicit instructions to avoid driving while impaired might improve patient care and promote highway safety. PMID:3177726

  2. Measuring tidal breathing parameters using a volumetric vest in neonates with and without lung disease.

    PubMed

    Olden, C; Symes, E; Seddon, P

    2010-11-01

    Lung function measurement is difficult in unsedated infants; tidal breathing parameters are a useful non-invasive surrogate, but even these measurements cause disturbance from applying a facemask. We investigated a novel volumetric vest system (FloRight), which measures volume changes of the respiratory system from changes in the magnetic fields induced by current-carrying coils around the entire chest and abdomen. Using a facemask and ultrasonic flowmeter as comparator, we assessed the validity and repeatability of tidal breathing parameters measured by FloRight in 10 healthy newborn infants during natural sleep. We also assessed the effect of a facemask on tidal volume and tidal expiratory flow parameters. To assess the ability of the FloRight system to detect disease, we compared the healthy infants with 11 infants suffering from bronchopulmonary dysplasia. Tidal parameters with the FloRight vest corresponded closely with facemask measurements. Mean difference, mask minus vest, for tidal volume was 0.096 ml (P < 0.05), with limits of agreement +4.5 to -4.3 ml. Coefficient of repeatability was similar for mask and vest measurements. Tidal volume measured by FloRight with mask in place (20.6 ml) was significantly higher than without mask (16.1 ml), but tidal expiratory flow parameters were not altered. FloRight measurements of tidal parameters were markedly different between the two groups of infants, with tidal volume per Kg significantly higher and tidal expiratory flow parameters significantly lower. Our findings suggest that the FloRight system is able to measure tidal breathing parameters accurately, in healthy newborn infants, without prior calibration on the infant. It appears to have at least sufficient sensitivity to detect severe respiratory disease. PMID:20872815

  3. Principles and techniques of blood pressure measurement

    PubMed Central

    Ogedegbe, Gbenga; Pickering, Thomas

    2013-01-01

    Although the mercury sphygmomanometer is widely regarded as the “gold standard” for office blood pressure measurement, the ban on use of mercury devices continues to diminish their role in office and hospital settings. To date, mercury devices have largely been phased out in US hospitals. This has led to the proliferation of non-mercury devices and has changed (probably for ever) the preferable modality of blood pressure measurement in clinic and hospital settings. In this article, the basic techniques of blood pressure measurement and the technical issues associated with measurements in clinical practice are discussed. The devices currently available for hospital and clinic measurements and their important sources of error are presented. Practical advice is given on how the different devices and measurement techniques should be used. Blood pressure measurements in different circumstances and in special populations such as infants, children, pregnant women, elderly persons, and obese subjects are discussed. PMID:20937442

  4. A medical cloud-based platform for respiration rate measurement and hierarchical classification of breath disorders.

    PubMed

    Fekr, Atena Roshan; Janidarmian, Majid; Radecka, Katarzyna; Zilic, Zeljko

    2014-01-01

    The measurement of human respiratory signals is crucial in cyberbiological systems. A disordered breathing pattern can be the first symptom of different physiological, mechanical, or psychological dysfunctions. Therefore, a real-time monitoring of the respiration patterns, as well as respiration rate is a critical need in medical applications. There are several methods for respiration rate measurement. However, despite their accuracy, these methods are expensive and could not be integrated in a body sensor network. In this work, we present a real-time cloud-based platform for both monitoring the respiration rate and breath pattern classification, remotely. The proposed system is designed particularly for patients with breathing problems (e.g., respiratory complications after surgery) or sleep disorders. Our system includes calibrated accelerometer sensor, Bluetooth Low Energy (BLE) and cloud-computing model. We also suggest a procedure to improve the accuracy of respiration rate for patients at rest positions. The overall error in the respiration rate calculation is obtained 0.53% considering SPR-BTA spirometer as the reference. Five types of respiration disorders, Bradapnea, Tachypnea, Cheyn-stokes, Kaussmal, and Biot's breathing are classified based on hierarchical Support Vector Machine (SVM) with seven different features. We have evaluated the performance of the proposed classification while it is individualized to every subject (case 1) as well as considering all subjects (case 2). Since the selection of kernel function is a key factor to decide SVM's performance, in this paper three different kernel functions are evaluated. The experiments are conducted with 11 subjects and the average accuracy of 94.52% for case 1 and the accuracy of 81.29% for case 2 are achieved based on Radial Basis Function (RBF). Finally, a performance evaluation has been done for normal and impaired subjects considering sensitivity, specificity and G-mean parameters of different kernel

  5. A Medical Cloud-Based Platform for Respiration Rate Measurement and Hierarchical Classification of Breath Disorders

    PubMed Central

    Fekr, Atena Roshan; Janidarmian, Majid; Radecka, Katarzyna; Zilic, Zeljko

    2014-01-01

    The measurement of human respiratory signals is crucial in cyberbiological systems. A disordered breathing pattern can be the first symptom of different physiological, mechanical, or psychological dysfunctions. Therefore, a real-time monitoring of the respiration patterns, as well as respiration rate is a critical need in medical applications. There are several methods for respiration rate measurement. However, despite their accuracy, these methods are expensive and could not be integrated in a body sensor network. In this work, we present a real-time cloud-based platform for both monitoring the respiration rate and breath pattern classification, remotely. The proposed system is designed particularly for patients with breathing problems (e.g., respiratory complications after surgery) or sleep disorders. Our system includes calibrated accelerometer sensor, Bluetooth Low Energy (BLE) and cloud-computing model. We also suggest a procedure to improve the accuracy of respiration rate for patients at rest positions. The overall error in the respiration rate calculation is obtained 0.53% considering SPR-BTA spirometer as the reference. Five types of respiration disorders, Bradapnea, Tachypnea, Cheyn-stokes, Kaussmal, and Biot's breathing are classified based on hierarchical Support Vector Machine (SVM) with seven different features. We have evaluated the performance of the proposed classification while it is individualized to every subject (case 1) as well as considering all subjects (case 2). Since the selection of kernel function is a key factor to decide SVM's performance, in this paper three different kernel functions are evaluated. The experiments are conducted with 11 subjects and the average accuracy of 94.52% for case 1 and the accuracy of 81.29% for case 2 are achieved based on Radial Basis Function (RBF). Finally, a performance evaluation has been done for normal and impaired subjects considering sensitivity, specificity and G-mean parameters of different kernel

  6. In vivo retinal blood flow measurement by Fourier domain Doppler optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Wang, Yimin; Tan, Ou; Huang, David

    2008-02-01

    The measurement of ocular blood flow is important in studying the pathophysiology and treatment of several leading causes of blindness. We present a method for in vivo human retinal flow measurement using Fourier domain optical coherence tomography. A double circular scanning pattern was used to scan the blood vessels around the optic nerve head 8 times over 2 seconds. The venous flow totaled 36.13 μl/min in the right eye of a volunteer. The flow difference was observed before and after breath holding. The fast flow measurement method did not require any assumption on the flow profile over time or space.

  7. Influence of breathing pattern and lung inflation on impulse oscillometry measurements in horses.

    PubMed

    Van Erck, E; Votion, D; Kirschvink, N; Genicot, B; Lindsey, J; Art, T; Lekeux, P

    2004-11-01

    The objective of this paper was to determine if changes in ventilation patterns could influence the outcome of respiratory function measurements performed with our impulse oscillometry system (IOS) in horses. In a first study, IOS tests were performed in vitro on six isolated equine lungs. Lung inflation levels were controlled by modifying depressurisation inside an artificial thorax and different ventilation patterns were imposed. In a second in vivo study, transient variations in breathing pattern were evaluated both with the IOS and a current reference technique (CRT) in five healthy mature horses after an intravenous (i.v.) injection of lobeline hydrochloride. In both studies, respiratory rate (RR, range: 7-42 breaths/min.) and tidal volume (V(T), range: 0.4-25 L) had minor or no influence on IOS parameters. The influence of lung inflation, most marked for resistance at 5 Hz (R(5 Hz)), was limited for the considered physiological range. In vivo, statistical models indicated that maximal changes in pleural pressure (Max Delta Ppl) and peak flows were the main determinants of the variability of the resistance (R(rs)) and the reactance (X(rs)) of the respiratory system. The fourfold increase in baseline Max Delta Ppl and peak flows obtained during hyperpnoea caused a significant increase in R(rs) at 5 and 10 Hz and a decrease in X(rs) at all frequencies. We conclude that IOS parameters are not influenced by tachypnoea, but will reflect alterations in respiratory mechanics caused by hyperpnoeic breathing. PMID:15501143

  8. Technical and practical issues for tidal breathing measurements of nasal nitric oxide in children.

    PubMed

    Beydon, Nicole; Chambellan, Arnaud; Alberti, Corinne; de Blic, Jacques; Clément, Annick; Escudier, Estelle; Le Bourgeois, Muriel

    2015-12-01

    To promote early screening of patients with suspected Primary Ciliary Dyskinesia (PCD), nasal nitric oxide (nNO) measurements during tidal breathing (TB) have been developed for children unable to ensure velum closure (VC) during breath hold or expiration against resistance. To investigate technical and practical issues related to TB-nNO methods in children referred for suspected or asserted PCD, we recorded, in a prospective multicenter study, TB-nNO (calculated as the mean of 5 peaks, 10 or 30 sec during tidal breathing) and VC-nNO when available. We studied 142 children (PCD diagnosis asserted in 47, excluded in 39). Nasal NO values were significantly different according to methods, VC-nNO being higher than TB-nNO (TB-nNO 5 peaks higher than mean of 10 or 30 sec). Specificity (90-94%) and sensitivity (86-97%) were similar between TB-nNO and VC-nNO methods. Age was more correlated with VC-nNO than with TB-nNO. TB-nNO could differ between the two nostrils by more than 10% (or 10 ppb when nNO absolute value lower 100 ppb) in 32-43% of the tested children, according to the different tidal breathing values, and was reproducible in the long term but influenced by ambient NO. Despite TB-nNO values being lower than VC-nNO, TB-nNO was found to be as discriminant for PCD, and probably more discriminant in children less than 8 years old, as the VC method. These results were obtained using the chemiluminescence technique which allows an easier assessment of relevant factors such as nasal permeability and ambient NO than the electrochemical technique. PMID:25731630

  9. Measurement and interpretation of arterial blood gases.

    PubMed

    Syabbalo, N

    1997-01-01

    Arterial blood gases and pH are routinely being measured in clinical practice, both to provide diagnosis and to guide therapy in critically ill patients. Oximetry is clinically useful in establishing the presence of hypoxaemia in patients with respiratory diseases. Oximetry is also a simple and reliable method for monitoring patients undergoing anaesthesia, sleep studies and cardiopulmonary exercise testing. The search continues for new innovative techniques for continuous transcutaneous and intra-arterial blood gas monitoring. This is essential in the management of critically ill patients because blood analysers provide only intermittent monitoring of arterial blood gases. PMID:9293061

  10. Transcutaneous measurement of volume blood flow

    NASA Technical Reports Server (NTRS)

    Daigle, R. E.; Mcleod, F. D.; Miller, C. W.; Histand, M. B.; Wells, M. K.

    1974-01-01

    Blood flow velocity measurements, using Doppler velocimeter, are described. The ability to measure blood velocity using ultrasound is derived from the Doppler effect; the change in frequency which occurs when sound is reflected or transmitted from a moving target. When ultrasound of the appropriate frequency is transmitted through a moving blood stream, the blood cells act as point scatterers of ultrasonic energy. If this scattered ultrasonic energy is detected, it is found to be shifted in frequency according to the velocity of the blood cells, nu, the frequency of the incident sound, f sub o, the speed of sound in the medium, c, and the angle between the sound beam and the velocity vector, o. The relation describing this effect is known as the Doppler equation. Delta f = 2 f sub o x nu x cos alpha/c. The theoretical and experimental methods are evaluated.

  11. Breath tests and airway gas exchange.

    PubMed

    Anderson, Joseph C; Hlastala, Michael P

    2007-01-01

    Measuring soluble gas in the exhaled breath is a non-invasive technique used to estimate levels of respiratory, solvent, and metabolic gases. The interpretation of these measurements is based on the assumption that the measured gases exchange in the alveoli. While the respiratory gases have a low blood-solubility and exchange in the alveoli, high blood-soluble gases exchange in the airways. The effect of airway gas exchange on the interpretation of these exhaled breath measurements can be significant. We describe airway gas exchange in relation to exhaled measurements of soluble gases that exchange in the alveoli. The mechanisms of airway gas exchange are reviewed and criteria for determining if a gas exchanges in the airways are provided. The effects of diffusion, perfusion, temperature and breathing maneuver on airway gas exchange and on measurement of exhaled soluble gas are discussed. A method for estimating the impact of airway gas exchange on exhaled breath measurements is presented. We recommend that investigators should carefully control the inspired air conditions and type of exhalation maneuver used in a breath test. Additionally, care should be taken when interpreting breath tests from subjects with pulmonary disease. PMID:16413216

  12. Simultaneous measurement of breathing rate and heart rate using a microbend multimode fiber optic sensor

    NASA Astrophysics Data System (ADS)

    Chen, Zhihao; Lau, Doreen; Teo, Ju Teng; Ng, Soon Huat; Yang, Xiufeng; Kei, Pin Lin

    2014-05-01

    We propose and demonstrate the feasibility of using a highly sensitive microbend multimode fiber optic sensor for simultaneous measurement of breathing rate (BR) and heart rate (HR). The sensing system consists of a transceiver, microbend multimode fiber, and a computer. The transceiver is comprised of an optical transmitter, an optical receiver, and circuits for data communication with the computer via Bluetooth. Comparative experiments conducted between the sensor and predicate commercial physiologic devices showed an accuracy of ±2 bpm for both BR and HR measurement. Our preliminary study of simultaneous measurement of BR and HR in a clinical trial conducted on 11 healthy subjects during magnetic resonance imaging (MRI) also showed very good agreement with measurements obtained from conventional MR-compatible devices.

  13. Simultaneous measurement of breathing rate and heart rate using a microbend multimode fiber optic sensor.

    PubMed

    Chen, Zhihao; Lau, Doreen; Teo, Ju Teng; Ng, Soon Huat; Yang, Xiufeng; Kei, Pin Lin

    2014-05-01

    We propose and demonstrate the feasibility of using a highly sensitive microbend multimode fiber optic sensor for simultaneous measurement of breathing rate (BR) and heart rate (HR). The sensing system consists of a transceiver, microbend multimode fiber, and a computer. The transceiver is comprised of an optical transmitter, an optical receiver, and circuits for data communication with the computer via Bluetooth. Comparative experiments conducted between the sensor and predicate commercial physiologic devices showed an accuracy of ±2 bpm for both BR and HR measurement. Our preliminary study of simultaneous measurement of BR and HR in a clinical trial conducted on 11 healthy subjects during magnetic resonance imaging (MRI) also showed very good agreement with measurements obtained from conventional MR-compatible devices. PMID:24788372

  14. Measurement of Olfactory Characteristics for Two Kinds of Scent in a Single Breath

    NASA Astrophysics Data System (ADS)

    Ohtsu, Kaori; Sato, Junta; Bannai, Yuichi; Okada, Kenichi

    This study describes a presentation technique of scent designed for users to recognize multiple scents during a very short time period. We measured the olfactory characteristics of subjects when two kinds of scents were presented in a single breath. We defined and measured the minimum ejection interval in which subjects could discriminate the two individually emitted pulses of scent, which we term “separable detection threshold”, and the minimum ejection interval in which they could specify both kinds of scents, “separable recognition threshold”. Further, “response time” and “duration of scent perception” were measured. As a result, we found the duration of scent perception and the separable recognition threshold were positively correlated. Knowledge of this olfactory characteristic brings us closer to being able to provide a greater sense of realism in multimedia environments, by describing more than one object by scent at the same time as the objects are seen on screen.

  15. Measurement of Human Blood and Plasma Volumes

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Szalkay, H. G. H.

    1987-01-01

    Report reviews techniques for measuring blood-plasma volume in humans. Common technique of using radioactive iodine isotope to label plasma albumin involves unwarranted risks from low-level radiation. Report emphasizes techniques using Evans-blue-dye (T-1824) labeling of albumin, hematocrit or hemoglobin/hematocrit measurements, or blood densitometry. In Evans-blue-dye technique, plasma volume determined from decrease in dye concentration occurring after small amount of dye solution injected into circulatory system. Subjection of Evans blue dye to test for carcinogenicity gave negative results.

  16. Breathing difficulties - first aid

    MedlinePlus

    ... a high altitude Blood clot in the lung Collapsed lung (pneumothorax) Heart attack Injury to the neck, chest wall, ... cavity with each breath. This can cause a collapsed lung . Bandage the wound with plastic wrap, a plastic ...

  17. Reliable noninvasive measurement of blood gases

    DOEpatents

    Thomas, Edward V.; Robinson, Mark R.; Haaland, David M.; Alam, Mary K.

    1994-01-01

    Methods and apparatus for, preferably, determining noninvasively and in vivo at least two of the five blood gas parameters (i.e., pH, PCO.sub.2, [HCO.sub.3.sup.- ], PO.sub.2, and O.sub.2 sat.) in a human. The non-invasive method includes the steps of: generating light at three or more different wavelengths in the range of 500 nm to 2500 nm; irradiating blood containing tissue; measuring the intensities of the wavelengths emerging from the blood containing tissue to obtain a set of at least three spectral intensities v. wavelengths; and determining the unknown values of at least two of pH, [HCO.sub.3.sup.- ], PCO.sub.2 and a measure of oxygen concentration. The determined values are within the physiological ranges observed in blood containing tissue. The method also includes the steps of providing calibration samples, determining if the spectral intensities v. wavelengths from the tissue represents an outlier, and determining if any of the calibration samples represents an outlier. The determination of the unknown values is performed by at least one multivariate algorithm using two or more variables and at least one calibration model. Preferably, there is a separate calibration for each blood gas parameter being determined. The method can be utilized in a pulse mode and can also be used invasively. The apparatus includes a tissue positioning device, a source, at least one detector, electronics, a microprocessor, memory, and apparatus for indicating the determined values.

  18. The use of ambulatory blood pressure measurement.

    PubMed

    Hodgkinson, James A; Tucker, Katherine L; Martin, Una; Beesley, Louise; McManus, Richard J

    2015-11-01

    Measurement of ambulatory blood pressure is recommended by the National Institute for Health and Care Excellence guidelines to confirm the diagnosis of hypertension in the UK. This article describes the use of ambulatory devices, and discusses the benefits and disadvantages of their use in clinical practice. PMID:26551492

  19. Multiplex analysis inflammatory cytokines in human blood, breath condensate, and urine matrices

    EPA Science Inventory

    Scientific evidence suggests that inflammation is associated with human health effects and health endpoints, yet most studies have focused on human populations that are already considered “unhealthy”.  As such, it is pertinent to measure inflammatory biomarkers in human biologica...

  20. Accuracy of noninvasive breath methane measurements using Fourier transform infrared methods on individual cows.

    PubMed

    Lassen, J; Løvendahl, P; Madsen, J

    2012-02-01

    Individual methane (CH(4)) production was recorded repeatedly on 93 dairy cows during milking in an automatic milking system (AMS), with the aim of estimating individual cow differences in CH(4) production. Methane and CO(2) were measured with a portable air sampler and analyzer unit based on Fourier transform infrared (FTIR) detection. The cows were 50 Holsteins and 43 Jerseys from mixed parities and at all stages of lactation (mean=156 d in milk). Breath was captured by the FTIR unit inlet nozzle, which was placed in front of the cow's head in each of the 2 AMS as an admixture to normal barn air. The FTIR unit was running continuously for 3 d in each of 2 AMS units, 1 with Holstein and another with Jersey cows. Air was analyzed every 20 s. From each visit of a cow to the AMS, CH(4) and CO(2) records were summarized into the mean, median, 75, and 90% quantiles. Furthermore, the ratio between CH(4) and CO(2) was used as a derived measure with the idea of using CO(2) in breath as a tracer gas to quantify the production of methane. Methane production records were analyzed with a mixed model, containing cow as random effect. Fixed effects of milk yield and daily intake of the total mixed ration and concentrates were also estimated. The repeatability of the CH(4)-to-CO(2) ratio was 0.39 for Holsteins and 0.34 for Jerseys. Both concentrate intake and total mixed ration intake were positively related to CH(4) production, whereas milk production level was not correlated with CH(4) production. In conclusion, the results from this study suggest that the CH(4)-to-CO(2) ratio measured using the noninvasive method is an asset of the individual cow and may be useful in both management and genetic evaluations. PMID:22281353

  1. Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults

    PubMed Central

    Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

    2016-01-01

    Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia. We measured breath ammonia in real time by quartz enhanced photoacoustic spectrometry and blood ammonia in 10 healthy and 10 cirrhotic participants. Each participant contributed 5 breath samples and blood for ammonia measurement within 1 h. We calculated the coefficient of variation (CV) for 5 breath ammonia values, reported medians of healthy and cirrhotic participants, and used scatterplots to display breath and blood ammonia. For healthy participants, mean age was 22 years (±4), 70% were men, and body mass index (BMI) was 27 (±5). For cirrhotic participants, mean age was 61 years (±8), 60% were men, and BMI was 31 (±7). Median blood ammonia for healthy participants was within normal range, 10 μmol L−1 (interquartile range (IQR), 3–18) versus 46 μmol L−1 (IQR, 23–66) for cirrhotic participants. Median breath ammonia was 379 pmol mL−1 CO2 (IQR, 265–765) for healthy versus 350 pmol mL−1 CO2 (IQR, 180–1013) for cirrhotic participants. CV was 17 ± 6%. There remains an important unmet need in the evaluation of systemic ammonia, and breath measurement continues to demonstrate promise to fulfill this need. Given the many differences between breath and blood ammonia measurement, we examined biological explanations for our findings in healthy and cirrhotic participants. We conclude that based upon these preliminary data breath may offer clinically important information this is not provided by blood ammonia. PMID:26658550

  2. News from the Breath Analysis Summit 2011.

    PubMed

    Corradi, Massimo; Mutti, Antonio

    2012-05-23

    This special section highlights some of the important work presented at the Breath Analysis Summit 2011, which was held in Parma (Italy) from 11 to 14 September 2011. The meeting, which was jointly organized by the International Association for Breath Research and the University of Parma, was attended by more than 250 delegates from 33 countries, and offered 34 invited lectures and 64 unsolicited scientific contributions. The summit was organized to provide a forum to scientists, engineers and clinicians to present their latest findings and to meet industry executives and entrepreneurs to discuss key trends, future directions and technologies available for breath analysis. A major focus was on nitric oxide, exhaled breath condensate, electronic nose, mass spectrometry and newer sensor technologies. Medical applications ranged from asthma and other respiratory diseases to gastrointestinal disease, occupational diseases, critical care and cancer. Most people identify breath tests with breathalysers used by police to estimate ethanol concentration in blood. However, breath testing has far more sophisticated applications. Breath analysis is rapidly evolving as a new frontier in medical testing for disease states in the lung and beyond. Every individual has a breath fingerprint-or 'breathprint'-that can provide useful information about his or her state of health. This breathprint comprises the many thousands of molecules that are expelled with each breath we exhale. Breath research in the past few years has uncovered the scientific and molecular basis for such clinical observations. Relying on mass spectrometry, we have been able to identify many such unique substances in exhaled breath, including gases, such as nitric oxide (NO) and carbon monoxide (CO), and a wide array of volatile organic compounds. Exhaled breath also carries aerosolized droplets that can be collected as an exhaled breath condensate that contains endogenously produced non-volatile compounds. Breath

  3. Method for measuring lead concentrations in blood

    DOEpatents

    Nogar, Nicholas S.

    2001-01-01

    Method for measuring lead concentrations in blood. The present invention includes the use of resonant laser ablation to analyze .ltoreq.1 .mu.L (or equivalent mass) samples of blood for lead content. A typical finger prick, for example, yields about 10 .mu.L. Solid samples may also readily be analyzed by resonant laser ablation. The sample is placed on a lead-free, electrically conducting substrate and irradiated with a single, focused laser beam which simultaneously vaporizes, atomizes, and resonantly ionizes an analyte of interest in a sample. The ions are then sorted, collected and detected using a mass spectrometer.

  4. [Usefulness of the integration between the values of the 1-hour blood xylose test and the hydrogen breath-test after xylose oral load for the indirect evaluation of mucosa damage].

    PubMed

    Zaniboni, M G; Lambertini, A; Romeo, N; Albini, P; Pozzi, M

    1985-01-01

    Considering 50 children affected by sub-acute gastrointestinal diseases by severe growth disorders, we have compared the "one-hour blood xylose test" with the "xylose and lactose H2 breath test, looking for a relationship with the duodeno-jejunal mucosal damage. Finally the integration between the "one hour blood xylose test" and the "xylose H2 breath test" may be useful in order to compare more exactly the results of both xylose tests with the mucosal damage. Lactose H2 breath test seems less reliable for our purposes because of the possible presence of children with lactase deficiences, hardly comparable with the mucosal damage. PMID:4094911

  5. Oscillometric blood pressure measurements: A signal analysis

    NASA Astrophysics Data System (ADS)

    Barbé, K.; Van Moer, W.; Lauwers, L.

    2010-07-01

    In this paper, the oscillometric waveform measured by automatic non-invasive blood pressure meters (NIBP) is analyzed by transforming the data from the time domain to the frequency domain. The signal's spectrum of the oscillometric waveform is in current literature badly understood or explored. The only known link between the oscillometric waveform and the blood pressure is the maximum of the oscillometry's envelope equalling the mean arterial pressure (MAP). This link is established under the assumption that the oscillometry is an AM-signal. Unfortunately, computing the MAP is difficult in practice due to the non-sinusoidal nature of the actual measured signals. In this paper, we construct the best AM-signal approximation of the oscillometry and explore its use to compute the MAP.

  6. 21 CFR 864.5950 - Blood volume measuring device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Blood volume measuring device. 864.5950 Section... § 864.5950 Blood volume measuring device. (a) Identification. A blood volume measuring device is a..., and total blood volume. (b) Classification. Class II (performance standards)....

  7. Breath Biomarkers to Measure Uptake of Volatile Organic Compounds by Bicyclists.

    PubMed

    Bigazzi, Alexander Y; Figliozzi, Miguel A; Luo, Wentai; Pankow, James F

    2016-05-17

    Breath biomarkers were used to study uptake of traffic-related volatile organic compounds (VOCs) from urban bicycling. Breath analysis was selected because it is one of the least invasive methods to assess urban traveler exposure. Research hurdles that were overcome included considering that factors other than on-road exposure can influence concentrations in the body, and absorbed doses during a trip can be small compared to baseline body burdens. Pre-trip, on-road, and post-trip breath concentrations and ambient air concentrations were determined for 26 VOCs for bicyclists traveling on different path types. Statistical analyses of the concentration data identified eight monoaromatic hydrocarbons potentially useful as breath biomarkers to compare differences in body levels brought about by urban travel choices. Breath concentrations of the biomarker compounds were significantly higher than background levels after riding on high-traffic arterial streets and on a path through a high-exposure industrial area, but not after riding on low-traffic local streets or on other off-street paths. Modeled effects of high-traffic streets on ambient concentrations were 100-200% larger than those of low-traffic streets; modeled effects of high-traffic streets on breath concentrations were 40-100% larger than those of low-traffic streets. Similar percentage increases in breath concentrations are expected for bicyclists in other cities. PMID:27097118

  8. Use of short-term breath measures to estimate daily methane production by cattle.

    PubMed

    Velazco, J I; Mayer, D G; Zimmerman, S; Hegarty, R S

    2016-01-01

    Methods to measure enteric methane (CH4) emissions from individual ruminants in their production environment are required to validate emission inventories and verify mitigation claims. Estimates of daily methane production (DMP) based on consolidated short-term emission measurements are developing, but method verification is required. Two cattle experiments were undertaken to test the hypothesis that DMP estimated by averaging multiple short-term breath measures of methane emission rate did not differ from DMP measured in respiration chambers (RC). Short-term emission rates were obtained from a GreenFeed Emissions Monitoring (GEM) unit, which measured emission rate while cattle consumed a dispensed supplement. In experiment 1 (Expt. 1), four non-lactating cattle (LW=518 kg) were adapted for 18 days then measured for six consecutive periods. Each period consisted of 2 days of ad libitum intake and GEM emission measurement followed by 1 day in the RC. A prototype GEM unit releasing water as an attractant (GEM water) was also evaluated in Expt. 1. Experiment 2 (Expt. 2) was a larger study based on similar design with 10 cattle (LW=365 kg), adapted for 21 days and GEM measurement was extended to 3 days in each of the six periods. In Expt. 1, there was no difference in DMP estimated by the GEM unit relative to the RC (209.7 v. 215.1 g CH(4)/day) and no difference between these methods in methane yield (MY, 22.7 v. 23.7 g CH(4)/kg of dry matter intake, DMI). In Expt. 2, the correlation between GEM and RC measures of DMP and MY were assessed using 95% confidence intervals, with no difference in DMP or MY between methods and high correlations between GEM and RC measures for DMP (r=0.85; 215 v. 198 g CH(4)/day SEM=3.0) and for MY (r=0.60; 23.8 v. 22.1 g CH(4)/kg DMI SEM=0.42). When data from both experiments was combined neither DMP nor MY differed between GEM- and RC-based measures (P>0.05). GEM water-based estimates of DMP and MY were lower than RC and GEM (P<0

  9. Effect of tubing deposition, breathing pattern, and temperature on aerosol mass distribution measured by cascade impactor.

    PubMed

    Gurses, Burak K; Smaldone, Gerald C

    2003-01-01

    Aerosols produced by nebulizers are often characterized on the bench using cascade impactors. We studied the effects of connecting tubing, breathing pattern, and temperature on mass-weighted aerodynamic particle size aerosol distributions (APSD) measured by cascade impaction. Our experimental setup consisted of a piston ventilator, low-flow (1.0 L/min) cascade impactor, two commercially available nebulizers that produced large and small particles, and two "T"-shaped tubes called "Tconnector(cascade)" and "Tconnector(nebulizer)" placed above the impactor and the nebulizer, respectively. Radiolabeled normal saline was nebulized using an airtank at 50 PSIG; APSD, mass balance, and Tconnector(cascade) deposition were measured with a gamma camera and radioisotope calibrator. Flow through the circuit was defined by the air tank (standing cloud, 10 L/min) with or without a piston pump, which superimposed a sinusoidal flow on the flow from the air tank (tidal volume and frequency of breathing). Experiments were performed at room temperature and in a cooled environment. With increasing tidal volume and frequency, smaller particles entered the cascade impactor (decreasing MMAD; e.g., Misty-Neb, 4.2 +/- 0.9 microm at lowest ventilation and 2.7 +/- 0.1 microm at highest, p = 0.042). These effects were reduced in magnitude for the nebulizer that produced smaller particles (AeroTech II, MMAD 1.8 +/- 0.1 to 1.3 +/- 0.1 microm; p = 0.0044). Deposition on Tconnector(cascade) increased with ventilation but was independent of cascade impactor flow. Imaging of the Tconnector(cascade) revealed a pattern of deposition unaffected by cascade impactor flow. These measurements suggest that changes in MMAD with ventilation were not artifacts of tubing deposition in the Tconnector(cascade). At lower temperatures, APSD distributions were more polydisperse. Our data suggest that, during patient inhalation, changes in particle distribution occur that are related to conditions in the tubing and

  10. How to measure blood pressure manually.

    PubMed

    Rushton, Melanie; Smith, Joyce

    2016-01-20

    Rationale and key points This article aims to help nurses to measure blood pressure (BP) manually using an aneroid sphygmomanometer. ▶ BP measurement is an essential clinical skill, and nurses must be competent in performing this procedure and taking accurate readings. ▶ Nurses should be aware of manual BP measurement techniques and understand the patient and environmental factors that may result in inaccurate readings that could compromise patient care. ▶ Nurses should regularly undertake manual BP measurement to ensure they remain competent to perform the procedure. Reflective activity Clinical skills articles can help update your practice and ensure it remains evidence based. Apply this article to your practice. Reflect on and write a short account of: 1. How reading this article will change your practice. 2. Further learning needs to extend your professional development. Subscribers can upload their reflective accounts at: rcni.com/portfolio . PMID:26786460

  11. Assessing and ensuring patient safety during breath-holding for radiotherapy

    PubMed Central

    Green, S; Stevens, A M; Clutton-Brock, T H

    2014-01-01

    Objective: While there is recent interest in using repeated deep inspiratory breath-holds, or prolonged single breath-holds, to improve radiotherapy delivery, breath-holding has risks. There are no published guidelines for monitoring patient safety, and there is little clinical awareness of the pronounced blood pressure rise and the potential for gradual asphyxia that occur during breath-holding. We describe the blood pressure rise during deep inspiratory breath-holding with air and test whether it can be abolished simply by pre-oxygenation and hypocapnia. Methods: We measured blood pressure, oxygen saturation (SpO2) and heart rate in 12 healthy, untrained subjects performing breath-holds. Results: Even for deep inspiratory breath-holds with air, the blood pressure rose progressively (e.g. mean systolic pressure rose from 133 ± 5 to 175 ± 8 mmHg at breakpoint, p < 0.005, and in two subjects, it reached 200 mmHg). Pre-oxygenation and hypocapnia prolonged breath-hold duration and prevented the development of asphyxia but failed to abolish the pressure rise. The pressure rise was not a function of breath-hold duration and was not signalled by any fall in heart rate (remaining at resting levels of 72 ± 2 beats per minute). Conclusion: Colleagues should be aware of the progressive blood pressure rise during deep inspiratory breath-holding that so far is not easily prevented. In breast cancer patients scheduled for breath-holds, we recommend routine screening for heart, cardiovascular, renal and cerebrovascular disease, routine monitoring of patient blood pressure and SpO2 during breath-holding and requesting patients to stop if systolic pressure rises consistently >180 mmHg and or SpO2 falls <94%. Advances in knowledge: There is recent interest in using deep inspiratory breath-holds, or prolonged single breath-holding techniques, to improve radiotherapy delivery. But there appears to be no clinical awareness of the risks to patients from breath

  12. Standardised exhaled breath collection for the measurement of exhaled volatile organic compounds by proton transfer reaction mass spectrometry

    PubMed Central

    2013-01-01

    Background Exhaled breath volatile organic compound (VOC) analysis for airway disease monitoring is promising. However, contrary to nitric oxide the method for exhaled breath collection has not yet been standardized and the effects of expiratory flow and breath-hold have not been sufficiently studied. These manoeuvres may also reveal the origin of exhaled compounds. Methods 15 healthy volunteers (34 ± 7 years) participated in the study. Subjects inhaled through their nose and exhaled immediately at two different flows (5 L/min and 10 L/min) into methylated polyethylene bags. In addition, the effect of a 20 s breath-hold following inhalation to total lung capacity was studied. The samples were analyzed for ethanol and acetone levels immediately using proton-transfer-reaction mass-spectrometer (PTR-MS, Logan Research, UK). Results Ethanol levels were negatively affected by expiratory flow rate (232.70 ± 33.50 ppb vs. 202.30 ± 27.28 ppb at 5 L/min and 10 L/min, respectively, p < 0.05), but remained unchanged following the breath hold (242.50 ± 34.53 vs. 237.90 ± 35.86 ppb, without and with breath hold, respectively, p = 0.11). On the contrary, acetone levels were increased following breath hold (1.50 ± 0.18 ppm) compared to the baseline levels (1.38 ± 0.15 ppm), but were not affected by expiratory flow (1.40 ± 0.14 ppm vs. 1.49 ± 0.14 ppm, 5 L/min vs. 10 L/min, respectively, p = 0.14). The diet had no significant effects on the gasses levels which showed good inter and intra session reproducibility. Conclusions Exhalation parameters such as expiratory flow and breath-hold may affect VOC levels significantly; therefore standardisation of exhaled VOC measurements is mandatory. Our preliminary results suggest a different origin in the respiratory tract for these two gasses. PMID:23837867

  13. Response of Retinal Blood Flow to Systemic Hyperoxia as Measured with Dual-Beam Bidirectional Doppler Fourier-Domain Optical Coherence Tomography

    PubMed Central

    Werkmeister, René M.; Palkovits, Stefan; Told, Reinhard; Gröschl, Martin; Leitgeb, Rainer A.; Garhöfer, Gerhard; Schmetterer, Leopold

    2012-01-01

    Purpose There is a long-standing interest in the study of retinal blood flow in humans. In the recent years techniques have been established to measure retinal perfusion based on optical coherence tomography (OCT). In the present study we used a technique called dual-beam bidirectional Doppler Fourier-domain optical coherence tomography (FD-OCT) to characterize the effects of 100% oxygen breathing on retinal blood flow. These data were compared to data obtained with a laser Doppler velocimeter (LDV). Methods 10 healthy subjects were studied on 2 study days. On one study day the effect of 100% oxygen breathing on retinal blood velocities was studied using dual-beam bidirectional Doppler FD-OCT. On the second study day the effect of 100% oxygen breathing on retinal blood velocities was assessed by laser Doppler velocimetry (LDV). Retinal vessel diameters were measured on both study days using a commercially available Dynamic Vessel Analyzer. Retinal blood flow was calculated based on retinal vessel diameters and red blood cell velocity. Results As expected, breathing of pure oxygen induced a pronounced reduction in retinal vessel diameters, retinal blood velocities and retinal blood flow on both study days (p<0.001). Blood velocity data correlated well between the two methods applied under both baseline as well as under hyperoxic conditions (r = 0.98 and r = 0.75, respectively). Data as obtained with OCT were, however, slightly higher. Conclusion A good correlation was found between red blood cell velocity as measured with dual-beam bidirectional Doppler FD-OCT and red blood cell velocity assessed by the laser Doppler method. Dual-beam bidirectional Doppler FD-OCT is a promising approach for studying retinal blood velocities in vivo. PMID:23029289

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  16. Laboratory and field evaluation of a SAW microsensor array for measuring perchloroethylene in breath.

    PubMed

    Groves, William A; Achutan, Chandran

    2004-12-01

    This article describes the laboratory and field performance evaluation of a small prototype instrument employing an array of six polymer-coated surface acoustic wave (SAW) sensors and a thermal desorption preconcentration unit for rapid analysis of perchloroethylene in breath. Laboratory calibrations were performed using breath samples spiked with perchloroethylene to prepare calibration standards spanning a concentration range of 0.1-10 ppm. A sample volume of 250 mL was preconcentrated on 40 mg of Tenax GR at a flow rate of 100 mL/min, followed by a dry air purge and thermal desorption at a temperature of 200 degrees C. The resulting pulse of vapor was passed over the sensor array at a flow rate of 20 mL/min and sensor responses were recorded and displayed using a laptop computer. The total time per analysis was 4.5 min. SAW sensor responses were linear, and the instrument's limit of detection was estimated to be 50 ppb based on the criterion that four of the six sensors show a detectable response. Field performance was evaluated at a commercial dry-cleaning operation by comparing prototype instrument results for breath samples with those of a portable gas chromatograph (NIOSH 3704). Four breath samples were collected from a single subject over the course of the workday and analyzed using the portable gas chromatograph (GC) and SAW instruments. An additional seven spiked breath samples were prepared and analyzed so that a broader range of perchloroethylene concentrations could be examined. Linear regression analysis showed excellent agreement between prototype instrument and portable GC breath sample results with a correlation coefficient of 0.99 and a slope of 1.04. The average error for the prototype instrument over a perchloroethylene breath concentration range of 0.9-7.2 ppm was 2.6% relative to the portable GC. These results demonstrate the field capabilities of SAW microsensor arrays for rapid analysis of organic vapors in breath. PMID:15742707

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

    PubMed Central

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

    2015-01-01

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

  18. Design and optimization of a widely tunable semiconductor laser for blood oxygenation and blood flow measurements

    NASA Astrophysics Data System (ADS)

    Feng, Yafei; Deng, Haoyu; Song, Guangyi; He, Jian-Jun

    2014-11-01

    A method for measuring blood oxygenation and blood flow rate using a single widely tunable semiconductor laser is proposed and investigated. It is shown that a 700-nm-band tunable laser gives the highest sensitivity for blood oxygen measurement. The corresponding tunable laser is designed using the V-coupled cavity structure. The wavelength tuning range can reach 8 nm, which is sufficient for the blood oxygenation measurement in the 700-nm-band by using the Beer- Lambert law. In contrast to conventional blood oxygenation measurement method based on two LEDs, the laser can be used at the same time to measure the blood flow rate based on the Doppler principle.

  19. Measurement of Liver Blood Flow: A Review

    PubMed Central

    Stansby, G. P.; Hobbs, K. E. F.; Hawkes, D. J.; Colchester, A. C. F.

    1991-01-01

    The study of hepatic haemodynamics is of importance in understanding both hepatic physiology and disease processes as well as assessing the effects of portosystemic shunting and liver transplantation. The liver has the most complicated circulation of any organ and many physiological and pathological processes can affect it1,2. This review surveys the methods available for assessing liver blood flow, examines the different parameters being measured and outlines problems of applicability and interpretation for each technique. The classification of these techniques is to some extent arbitrary and several so called “different” methods may share certain common principles. The methods reviewed have been classified into two groups (Table 1): those primarily reflecting flow through discrete vessels or to the whole organ and those used to assess local microcirculatory blood flow. All techniques have their advantages and disadvantages and in some situations a combination may provide the most information. In addition, because of the many factors affecting liver blood flow and sinusoidal perfusion, readings in a single subject may vary depending on positioning, recent food intake, anxiety, anaesthesia and drug therapy. This must be borne in mind if different studies are to be meaningfully compared. PMID:1931785

  20. Human breath measurements in a clean-air chamber to determine half-lives for volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Gordon, Sydney M.; Wallace, Lance A.; Pelllzzari, Edo D.; O'Neill, Hugh J.

    The expired breath of four non-occupationally exposed subjects was monitored following exposure at near-normal environmental concentrations using a specially developed pulmonary clearance technique. The four were exposed to polluted air on a heavily trafficked freeway or at a local dry-cleaning establishment, then spent the next 10 h in a clean-air environmental chamber. Breath and chamber-air samples were collected at regular intervals throughout the 10-h period and analyzed for the presence of selected target compounds. The breath levels of two of the compounds were elevated and decreased slowly with time once the subjects began to breathe clean air. Nonlinear least-squares fitting of the decay-uptake curves permitted the calculation of biological half-lives. Several of the target compounds occurred, however, at very low levels, and the resultant experimental scatter limited the value of these measurements. Higher initial exposures to most of the target compounds would have improved the reliability of the estimates.

  1. Breath odor

    MedlinePlus

    ... tube) in place. The breath may have an ammonia-like odor (also described as urine-like or " ... kidney failure (can cause breath to smell like ammonia ) Diabetes (fruity or sweet chemical smell associated with ...

  2. Breathing Problems

    MedlinePlus

    ... re not getting enough air. Sometimes mild breathing problems are from a stuffy nose or hard exercise. ... emphysema or pneumonia cause breathing difficulties. So can problems with your trachea or bronchi, which are part ...

  3. Breathing difficulty

    MedlinePlus

    ... pulmonary disease (COPD), such as chronic bronchitis or emphysema Other lung disease Pneumonia Pulmonary hypertension Problems with ... of breath; Breathlessness; Difficulty breathing; Dyspnea Images Lungs Emphysema References Kraft M. Approach to the patient with ...

  4. Breath odor

    MedlinePlus

    ... is a potentially life-threatening condition. Breath that smells like feces can occur with prolonged vomiting , especially ... renal failure Bowel obstruction (can cause breath to smell like feces) Bronchiectasis Chronic kidney failure (can cause ...

  5. Automatic Blood Pressure Measurements During Exercise

    NASA Technical Reports Server (NTRS)

    Weaver, Charles S.

    1985-01-01

    Microprocessor circuits and a computer algorithm for automatically measuring blood pressure during ambulatory monitoring and exercise stress testing have been under development at SRI International. A system that records ECG, Korotkov sound, and arm cuff pressure for off-line calculation of blood pressure has been delivered to NASA, and an LSLE physiological monitoring system that performs the algorithm calculations in real-time is being constructed. The algorithm measures the time between the R-wave peaks and the corresponding Korotkov sound on-set (RK-interval). Since the curve of RK-interval versus cuff pressure during deflation is predictable and slowly varying, windows can be set around the curve to eliminate false Korotkov sound detections that result from noise. The slope of this curve, which will generally decrease during exercise, is the inverse of the systolic slope of the brachial artery pulse. In measurements taken during treadmill stress testing, the changes in slopes of subjects with coronary artery disease were markedly different from the changes in slopes of healthy subjects. Measurements of slope and O2 consumption were also made before and after ten days of bed rest during NASA/Ames Research Center bed rest studies. Typically, the maximum rate of O2 consumption during the post-bed rest test is less than the maximum rate during the pre-bed rest test. The post-bed rest slope changes differ from the pre-bed rest slope changes, and the differences are highly correlated with the drop in the maximum rate of O2 consumption. We speculate that the differences between pre- and post-bed rest slopes are due to a drop in heart contractility.

  6. Numerical simulation of noninvasive blood pressure measurement.

    PubMed

    Hayashi, Satoru; Hayase, Toshiyuki; Shirai, Atsushi; Maruyama, Masaru

    2006-10-01

    In this paper, a simulation model based on the partially pressurized collapsible tube model for reproducing noninvasive blood pressure measurement is presented. The model consists of a collapsible tube, which models the pressurized part of the artery, rigid pipes connected to the collapsible tube, which model proximal and distal region far from the pressurized part, and the Windkessel model, which represents the capacitance and the resistance of the distal part of the circulation. The blood flow is simplified to a one-dimensional system. Collapse and expansion of the tube is represented by the change in the cross-sectional area of the tube considering the force balance acting on the tube membrane in the direction normal to the tube axis. They are solved using the Runge-Kutta method. This simple model can easily reproduce the oscillation of inner fluid and corresponding tube collapse typical for the Korotkoff sounds generated by the cuff pressure. The numerical result is compared with the experiment and shows good agreement. PMID:16995754

  7. The breathing effect of the LF/HF ratio in the heart rate variability measurements of athletes.

    PubMed

    Saboul, Damien; Pialoux, Vincent; Hautier, Christophe

    2014-01-01

    The purpose of this study was to measure the influence of breathing frequency (BF) on heart rate variability (HRV) and specifically on the Low Frequency/High Frequency (LF/HF) ratio in athletes. Fifteen male athletes were subjected to HRV measurements under six randomised breathing conditions: spontaneous breathing frequency (SBF) and five others at controlled breathing frequencies (CBF) (0.20; 0.175; 0.15; 0.125 and 0.10 Hz). The subjects were divided in two groups: the first group included athletes with SBF <0.15 Hz (infSBF) and the second athletes with SBF higher than 0.15 Hz (supSBF). Fatigue and training load were evaluated using a validated questionnaire. There was no difference between the two groups for the fatigue questionnaire and training load. However, the LF/HF ratio during SBF was higher in infSBF than in supSBF (6.82 ± 4.55 vs. 0.72 ± 0.52; p<0.001). The SBF and LF/HF ratio were significantly correlated (R=-0.69; p=0.004). For the five CBF, no differences were found between groups; however, LF/HF ratios were very significantly different between sessions at 0.20; 0.175; 0.15 Hz and 0.125; 0.10 Hz. In this study, BF was the main modulator of the LF/HF ratio in both controlled breathing and spontaneous breathing. Although, none of the subjects of the infSBF group were overtrained, during SBF they all presented LF/HF ratios higher than four commonly interpreted as an overtraining syndrome. During each CBF, all athletes presented spectral energy mainly concentrated around their BF. Consequently, spectral energy was located either in LF or in HF band. These results demonstrate that the LF/HF ratio is unreliable for studying athletes presenting SBF close to 0.15 Hz leading to misclassification in fatigue. PMID:24444219

  8. 21 CFR 870.1130 - Noninvasive blood pressure measurement system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Noninvasive blood pressure measurement system. 870.1130 Section 870.1130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Noninvasive blood pressure measurement system. (a) Identification. A noninvasive blood pressure...

  9. Blood Pressure Measurement: Clinic, Home, Ambulatory, and Beyond

    PubMed Central

    Drawz, Paul E.; Abdalla, Mohamed; Rahman, Mahboob

    2014-01-01

    Blood pressure has traditionally been measured in the clinic setting using the auscultory method and a mercury sphygmomanometer. Technological advances have led to improvements in measuring clinic blood pressure and allowed for measuring blood pressures outside the clinic. This review outlines various methods for evaluating blood pressure and the clinical utility of each type of measurement. Home blood pressures and 24 hour ambulatory blood pressures have improved our ability to evaluate risk for target organ damage and hypertension related morbidity and mortality. Measuring home blood pressures may lead to more active participation in health care by patients and has the potential to improve blood pressure control. Ambulatory blood pressure monitoring enables the measuring nighttime blood pressures and diurnal changes, which may be the most accurate predictors of risk associated with elevated blood pressure. Additionally, reducing nighttime blood pressure is feasible and may be an important component of effective antihypertensive therapy. Finally, estimating central aortic pressures and pulse wave velocity are two of the newer methods for assessing blood pressure and hypertension related target organ damage. PMID:22521624

  10. Previous blood pressure measurement and associated factors in student adolescents

    PubMed Central

    Magalhães, Marina Gabriella Pereira de Andrada; Farah, Breno Quintella; de Barros, Mauro Virgilio Gomes; Ritti-Dias, Raphael Mendes

    2015-01-01

    Objective To identify prevalence of previous blood pressure measurement and analyze some associated factors in adolescents. Methods This cross-sectional study included 6,077 adolescents aged 14 to 19 years. Demographic characteristics included (sex, age, period of study, region of residence, work, skin color, and economic) status, history of blood pressure measurement within last 12 months, local of blood pressure measurement, and reading obtained. To assess associations between previous blood pressure measurement with demographic characteristics and high blood pressure we used descriptive statistics and logistic regression analysis. Results Out of the adolescents, 56.8% reported no blood pressure measurement within the last 12 months. The health centers and the physician’s office were most mentioned places for blood pressure measurement (28.3% and 36.9%, respectively). Boys (odds ratio of 1.64 95%CI: 1.46-1.84) aged 14 to 16 years (odds ratio of 1.12; 95%CI: 1.01-1.25), whose economic status was unfavorable (odds ratio of 1.48; 95%CI: 1.32-1.67) were significantly associated with no blood pressure measurement. Working was a protective factor for was not blood pressure measurement (odds ratio of 0.84; 95%CI: 0.73-0.97). Conclusion Most of adolescents did not have their blood pressure measured within the last 12 months. Boys aged 14 to 16 years and those with unfavorable economic status had higher chance of not having their blood pressure measured. PMID:26466061

  11. Measurement of Retinal Blood Flow Using Fluorescently Labeled Red Blood Cells1,2,3

    PubMed Central

    Kornfield, Tess E.

    2015-01-01

    Abstract Blood flow is a useful indicator of the metabolic state of the retina. However, accurate measurement of retinal blood flow is difficult to achieve in practice. Most existing optical techniques used for measuring blood flow require complex assumptions and calculations. We describe here a simple and direct method for calculating absolute blood flow in vessels of all sizes in the rat retina. The method relies on ultrafast confocal line scans to track the passage of fluorescently labeled red blood cells (fRBCs). The accuracy of the blood flow measurements was verified by (1) comparing blood flow calculated independently using either flux or velocity combined with diameter measurements, (2) measuring total retinal blood flow in arterioles and venules, (3) measuring blood flow at vessel branch points, and (4) measuring changes in blood flow in response to hyperoxic and hypercapnic challenge. Confocal line scans oriented parallel and diagonal to vessels were used to compute fRBC velocity and to examine velocity profiles across the width of vessels. We demonstrate that these methods provide accurate measures of absolute blood flow and velocity in retinal vessels of all sizes. PMID:26082942

  12. How Accurate Are Blood (or Breath) Tests for Identifying Self-Reported Heavy Drinking Among People with Alcohol Dependence?

    PubMed Central

    Bertholet, Nicolas; Winter, Michael R.; Cheng, Debbie M.; Samet, Jeffrey H.; Saitz, Richard

    2014-01-01

    Aims Managing patients with alcohol dependence includes assessment for heavy drinking, typically by asking patients. Some recommend biomarkers to detect heavy drinking but evidence of accuracy is limited. Methods Among people with dependence, we assessed the performance of disialo-carbohydrate-deficient transferrin (%dCDT, ≥1.7%), gamma-glutamyltransferase (GGT, ≥66 U/l), either %dCDT or GGT positive, and breath alcohol (> 0) for identifying 3 self-reported heavy drinking levels: any heavy drinking (≥4 drinks/day or >7 drinks/week for women, ≥5 drinks/day or >14 drinks/week for men), recurrent (≥5 drinks/day on ≥5 days) and persistent heavy drinking (≥5 drinks/day on ≥7 consecutive days). Subjects (n = 402) with dependence and current heavy drinking were referred to primary care and assessed 6 months later with biomarkers and validated self-reported calendar method assessment of past 30-day alcohol use. Results The self-reported prevalence of any, recurrent and persistent heavy drinking was 54, 34 and 17%. Sensitivity of %dCDT for detecting any, recurrent and persistent self-reported heavy drinking was 41, 53 and 66%. Specificity was 96, 90 and 84%, respectively. %dCDT had higher sensitivity than GGT and breath test for each alcohol use level but was not adequately sensitive to detect heavy drinking (missing 34–59% of the cases). Either %dCDT or GGT positive improved sensitivity but not to satisfactory levels, and specificity decreased. Neither a breath test nor GGT was sufficiently sensitive (both tests missed 70–80% of cases). Conclusions Although biomarkers may provide some useful information, their sensitivity is low the incremental value over self-report in clinical settings is questionable. PMID:24740846

  13. Sensitivity and specificity of an abbreviated 13C-mixed triglyceride breath test for measurement of pancreatic exocrine function

    PubMed Central

    Meier, Viola; Wolfram, Kristina U; Rosien, Ulrich; Layer, Peter

    2014-01-01

    Background A modified 13C-mixed triglyceride breath test (13C -MTGT) detects moderate pancreatic exocrine insufficiency noninvasively and reliably, but it requires prolonged breath sampling (6 hours (hr)). Objective We aimed to investigate whether 13C -MTGT can be abbreviated, to optimize clinical usability. Methods We analyzed the 13C-MTGT of 200 consecutive patients, retrospectively. Cumulative 1–5 hr 13C-exhalation values were compared with the standard parameter (6-hr cumulative 13C-exhalation). We determined the sensitivity and specificity of shortened breath sampling periods, by comparison with the normal values from 10 healthy volunteers, whom also underwent a secretin test to quantitate pancreatic secretion. Moreover, we evaluated the influence of gastric emptying (GE), using a 13C-octanoic acid breath test in a subset (N = 117). Results The 1–5 hr cumulative 13C-exhalation tests correlated highly and significantly with the standard parameter (p < 0.0001). Sensitivity for detection of impaired lipolysis was high (≥77%), but the specificity was low (≥38%) for the early measurements. Both parameters were high after 4 hrs (88% and 94%, respectively) and 5 hrs (98% and 91%, respectively). Multivariate linear correlation analysis confirmed that GE strongly influenced early postprandial 13C-exhalation during the 13C-MTGT. Conclusion Shortening of the 13C -MTGT from 6 to 4 hrs of duration was associated with similar diagnostic accuracy, yet increased clinical usability. The influence of GE on early postprandial results of the 13C-MTGT precluded further abbreviation of the test. PMID:25083286

  14. Heat transfer analysis for peripheral blood flow measurement system

    NASA Astrophysics Data System (ADS)

    Nagata, Koji; Hattori, Hideharu; Sato, Nobuhiko; Ichige, Yukiko; Kiguchi, Masashi

    2009-06-01

    Some disorders such as circulatory disease and metabolic abnormality cause many problems to peripheral blood flow condition. Therefore, frequent measurement of the blood flow condition is bound to contribute to precaution against those disorders and to control of conditions of the diseases. We propose a convenient means of blood flow volume measurement at peripheral part, such as fingertips. Principle of this measurement is based on heat transfer characteristics of peripheral part containing the blood flow. Transition response analysis of skin surface temperature has provided measurement model of the peripheral blood flow volume. We developed the blood flow measurement system based on that model and evaluated it by using artificial finger under various temperature conditions of ambience and internal fluid. The evaluation results indicated that proposed method could estimate the volume of the fluid regardless of temperature condition of them. Finally we applied our system to real finger testing and have obtained results correlated well with laser Doppler blood flow meter values.

  15. Reproducibility of measuring cerebral blood flow by laser-Doppler flowmetry in mice.

    PubMed

    Tajima, Yosuke; Takuwa, Hiroyuki; Kawaguchi, Hiroshi; Masamoto, Kazuto; Ikoma, Yoko; Seki, Chie; Taniguchi, Junko; Kanno, Iwao; Saeki, Naokatsu; Ito, Hiroshi

    2014-01-01

    Laser-Doppler flowmetry has been widely used to trace hemodynamic changes in experimental stroke research. The purpose of the present study was to evaluate the day-to-day test-retest reproducibility of measuring cerebral blood flow by LDF in awake mice. The flux indicating cerebral blood flow (CBF), red blood cell (RBC) velocity, and RBC concentration were measured with LDF via cranial windows for the bilateral somatosensory cortex in awake mice. LDF measurements were performed three times, at baseline, 1 hour after, and 7 days after the baseline measurement. Moreover, breathing rate (BR) and partial pressure of transcutaneous CO₂ (PtCO₂) were measured simultaneously with LDF measurement. Intraclass correlation coefficient (ICC) and within-subject coefficient of variation (CVw) were calculated. CBF, RBC velocity, and RBC concentration showed good day-to-day test-retest reproducibility (ICC: 0.61 - 0.95, CVw: 8.3% - 15.4%). BR and PtCO₂ in awake mice were stable during the course of the experiments. The evaluation of cerebral microcirculation using LDF appears to be applicable to long-term studies. PMID:24389142

  16. Measurement Adherence in the Blood Pressure Self-Measurement Room

    PubMed Central

    Buus, Niels Henrik; Jespersen, Bente; Ahrendt, Peter; Bertelsen, Olav W.; Toftegaard, Thomas S.

    2013-01-01

    Abstract Background: Patients with hypertension or receiving blood pressure (BP)-lowering treatment are often required to self-measure their BP in a dedicated self-measurement room before consultation. Current praxis does not guarantee valid measurements, possibly leading to misdiagnoses or inappropriate antihypertensive medication. The aim of this study was to investigate patients' ability to correctly self-report and follow recommendations. Patients and Methods: We used a context-aware system to gather information on BP measurements and relevant context parameters. Patients were not informed that the system automatically collected behavior data and were instructed to self-report their measurements on a paper sheet as usual. We then compared the automatically recorded data with the self-reported data in order to detect any nonadherent reporting behavior. Also, we investigated the patients' ability to adhere to the measurement recommendations. Results: We found that (1) a third of all 113 participating patients failed to self-report measured BP data correctly and (2) none of the 642 measurements obtained adhered fully to the recommendations. Conclusions: Results indicate that context-aware technology may be useful for accurately modeling aspects of nonadherent patient behavior. This may be used to inform staff of the validity of the measurement and pinpoint patients in need of additional training or to design better aids to assist the patients. The developed system is generally applicable to other self-measurement environments, including the home setting and remote outpatient clinics, as it is built using telemedicine technology and thus well suited for remote monitoring and diagnosis. PMID:23631589

  17. Signal quality measures for unsupervised blood pressure measurement.

    PubMed

    Sukor, J Abdul; Redmond, S J; Chan, G S H; Lovell, N H

    2012-03-01

    Accurate systolic and diastolic pressure estimation, using automated blood pressure measurement, is difficult to achieve when the transduced signals are contaminated with noise or interference, such as movement artifact. This study presents an algorithm for automated signal quality assessment in blood pressure measurement by determining the feasibility of accurately detecting systolic and diastolic pressures when corrupted with various levels of movement artifact. The performance of the proposed algorithm is compared to a manually annotated reference scoring (RS). Based on visual representations and audible playback of Korotkoff sounds, the creation of the RS involved two experts identifying sections of the recorded sounds and annotating sections of noise contamination. The experts determined the systolic and diastolic pressure in 100 recorded Korotkoff sound recordings, using a simultaneous electrocardiograph as a reference signal. The recorded Korotkoff sounds were acquired from 25 healthy subjects (16 men and 9 women) with a total of four measurements per subject. Two of these measurements contained purposely induced noise artifact caused by subject movement. Morphological changes in the cuff pressure signal and the width of the Korotkoff pulse were extracted features which were believed to be correlated with the noise presence in the recorded Korotkoff sounds. Verification of reliable Korotkoff pulses was also performed using extracted features from the oscillometric waveform as recorded from the inflatable cuff. The time between an identified noise section and a verified Korotkoff pulse was the key feature used to determine the validity of possible systolic and diastolic pressures in noise contaminated Korotkoff sounds. The performance of the algorithm was assessed based on the ability to: verify if a signal was contaminated with any noise; the accuracy, sensitivity and specificity of this noise classification, and the systolic and diastolic pressure

  18. Velocity measurements in whole blood using acoustic resolution photoacoustic Doppler.

    PubMed

    Brunker, Joanna; Beard, Paul

    2016-07-01

    Acoustic resolution photoacoustic Doppler velocimetry promises to overcome the spatial resolution and depth penetration limitations of current blood flow measuring methods. Despite successful implementation using blood-mimicking fluids, measurements in blood have proved challenging, thus preventing in vivo application. A common explanation for this difficulty is that whole blood is insufficiently heterogeneous relative to detector frequencies of tens of MHz compatible with deep tissue photoacoustic measurements. Through rigorous experimental measurements we provide new insight that refutes this assertion. We show for the first time that, by careful choice of the detector frequency and field-of-view, and by employing novel signal processing methods, it is possible to make velocity measurements in whole blood using transducers with frequencies in the tens of MHz range. These findings have important implications for the prospects of making deep tissue measurements of blood flow relevant to the study of microcirculatory abnormalities associated with cancer, diabetes, atherosclerosis and other conditions. PMID:27446707

  19. Velocity measurements in whole blood using acoustic resolution photoacoustic Doppler

    PubMed Central

    Brunker, Joanna; Beard, Paul

    2016-01-01

    Acoustic resolution photoacoustic Doppler velocimetry promises to overcome the spatial resolution and depth penetration limitations of current blood flow measuring methods. Despite successful implementation using blood-mimicking fluids, measurements in blood have proved challenging, thus preventing in vivo application. A common explanation for this difficulty is that whole blood is insufficiently heterogeneous relative to detector frequencies of tens of MHz compatible with deep tissue photoacoustic measurements. Through rigorous experimental measurements we provide new insight that refutes this assertion. We show for the first time that, by careful choice of the detector frequency and field-of-view, and by employing novel signal processing methods, it is possible to make velocity measurements in whole blood using transducers with frequencies in the tens of MHz range. These findings have important implications for the prospects of making deep tissue measurements of blood flow relevant to the study of microcirculatory abnormalities associated with cancer, diabetes, atherosclerosis and other conditions. PMID:27446707

  20. [Student diagnostic vignette. How to measure office blood pressure].

    PubMed

    Krzesinski, J-M; Saint-Remy, A

    2012-09-01

    Routinely measuring blood pressure is still performed according to the auscultatory method using recognition of Korotkoff sounds. This usual technique is, however, often mishandled and is thus a source of error in the estimation of the true blood pressure level. Accuracy of such measure is, however, of paramount importance to be useful in daily medical practice. This methodology paper more specifically written for medical students recalls the essential principles of blood pressure measurement at the medical office, but also at home. PMID:23115851

  1. Breathing Problems

    MedlinePlus

    When you're short of breath, it's hard or uncomfortable for you to take in the oxygen your body needs. You may feel as if you're ... stuffy nose or hard exercise. But shortness of breath can also be a sign of a serious ...

  2. Exploring effects of therapeutic massage and patient teaching in the practice of diaphragmatic breathing on blood pressure, stress, and anxiety in hypertensive African-American women: an intervention study.

    PubMed

    Jefferson, Lenetra L

    2010-07-01

    The problem of hypertension among African-Americans is one of the major areas of health disparities. The American Heart Association (2009) noted that the prevalence of hypertension among African-Americans is perhaps among the highest in the world and this is particularly so among African-American women (44.0%). The purpose of this study was to determine how therapeutic chair massage and patient teaching in diaphragmatic breathing affected African-American women's blood pressure, stress, and anxiety levels over one week or six weeks time periods. A Modified Stress, Coping, and Adaptation Model (Roy, 1976; Lazarus, 1966), Descriptives, T-tests, Pearson Product Moment Correlations, Multivariate analysis of variance (MANOVA), and Multivariate analysis of variance with covariate (MANCOVA) were used. Descriptive statistics indicated a significance for decreased systolic blood pressure levels for the one week post massage intervention measurement with p = .01, diastolic blood pressure level significance for the same group p = .02, significance for this group's State Trait Anxiety Inventory (STAI) Y2 Scale score p = .01, and Roy's Largest Root p = .03. PMID:20857772

  3. Methods of Blood Pressure Measurement in the ICU

    PubMed Central

    Lehman, Li-wei H.; Saeed, Mohammed; Talmor, Daniel; Mark, Roger; Malhotra, Atul

    2013-01-01

    Objective Minimal clinical research has investigated the significance of different blood pressure monitoring techniques in the ICU and whether systolic vs. mean blood pressures should be targeted in therapeutic protocols and in defining clinical study cohorts. The objectives of this study are to compare real-world invasive arterial blood pressure with noninvasive blood pressure, and to determine if differences between the two techniques have clinical implications. Design We conducted a retrospective study comparing invasive arterial blood pressure and noninvasive blood pressure measurements using a large ICU database. We performed pairwise comparison between concurrent measures of invasive arterial blood pressure and noninvasive blood pressure. We studied the association of systolic and mean invasive arterial blood pressure and noninvasive blood pressure with acute kidney injury, and with ICU mortality. Setting Adult intensive care units at a tertiary care hospital. Patients Adult patients admitted to intensive care units between 2001 and 2007. Interventions None. Measurements and Main Results Pairwise analysis of 27,022 simultaneously measured invasive arterial blood pressure/noninvasive blood pressure pairs indicated that noninvasive blood pressure overestimated systolic invasive arterial blood pressure during hypotension. Analysis of acute kidney injury and ICU mortality involved 1,633 and 4,957 patients, respectively. Our results indicated that hypotensive systolic noninvasive blood pressure readings were associated with a higher acute kidney injury prevalence (p = 0.008) and ICU mortality (p < 0.001) than systolic invasive arterial blood pressure in the same range (≤70 mm Hg). Noninvasive blood pressure and invasive arterial blood pressure mean arterial pressures showed better agreement; acute kidney injury prevalence (p = 0.28) and ICU mortality (p = 0.76) associated with hypotensive mean arterial pressure readings (≤60 mm Hg) were independent of

  4. THE UNIQUE VALUE OF BREATH BIOMARKERS FOR ESTIMATING PHARMACOKINETIC RATE CONSTANTS AND BODY BURDEN FROM ENVIRONMENTAL EXPOSURES

    EPA Science Inventory

    Although detection of breath odor is the oldest of the medical diagnostic techniques, blood and urine biomarker measurements are the current "gold standard" for modern exposure and health assessments. Of late, it has been recognized that collecting exhaled breath is an attractiv...

  5. A headset-mounted mini sampler for measuring exposure to welding aerosol in the breathing zone.

    PubMed

    Lidén, Göran; Surakka, Jouni

    2009-03-01

    There is a need for a small personal aerosol sampler for measuring occupational exposure to airborne particles in the breathing zone. Existing aerosol samplers are too large to be mounted inside modern welder's protective equipment without disturbing the worker. A headset-mounted mini sampler has been developed to fill this gap with focus on manganese exposure. This mini sampler is easy to use and can be mounted inside modern, slimline welder's face shield. The mini sampler is based on a commercially available 13-mm filter holder that has been modified to incorporate an inlet nozzle made of aluminium. The nominal flow rate of the mini sampler is 0.75 l min(-1). The mini sampler is to be worn mounted on a headset, modified from professional microphone headsets. Several aspects related to using the mini sampler have been tested by personal and static sampling at five workplaces and in the laboratory. Four headset models were tested for their suitability as a sampler holder, of which three models were accepted by the welders. The sampling bias of the mini sampler versus the IOM sampler and the open-face 25-mm filter holder, respectively, depends on the size distribution of the sampled aerosol. At the lowest encountered mass concentration ratio of the open-face 25-mm filter holder to the IOM sampler (0.65), the sampling bias of the mini sampler versus the IOM sampler is approximately -26% and versus the open-face 25-mm filter holder is approximately +12%. For manganese, the negative root mean square (RMS) sampling bias of the mini sampler versus the IOM sampler is -0.046 and versus the open-face 25-mm filter holder is non-significant. Both these biases are statistically non-significant. The mini sampler can therefore be employed for determining welders' occupational exposure to manganese. The pressure drop across the filter can become excessive due to the small filtration area. Compared to the Casella Apex pump, the SKC AirChek2000 pump was generally found to be able

  6. A new method of non-invasive blood pressure measurement

    NASA Astrophysics Data System (ADS)

    Gu, Liangling; Yang, Yongming; Yu, Chengbo; Guo, Qiaohui; Zhu, Gang

    2005-12-01

    Blood pressure reflects a person's health.It is proposed here that the method of detecting blood pressure may be the key to improving the precision of blood pressure measurements. The oscillometric blood pressure measurement technique is widely used in automatic blood pressure measurement instruments correctly. A method of blood pressure measurement by oscillometric method is first presented. In the oscillometric method, the basic principle of the "feature point" method and the "amplitude characteristic ratios" method is also explained and discussed here. A new method of blood pressure measurement, namely the coefficient difference comparative method, is proposed here,which is based on the feature point method and amplitude characteristic ratios method. The method is proved both effective and reliable through the analysis of many cases and clinical tests. Utilizing Visual C++, software for this new and novel method was developed and passed criterion simulation apparatus test. When applied in hospital situation, its error was +/-5%. It is concluded that the oscillometric blood pressure measurement method can provide better means of blood pressure measurements reference for doctors.

  7. Videodensitometry for measuring blood vessel diameter.

    PubMed

    Hoornstra, K; Hanselman, J M; Holland, W P; De Wey Peters, G W; Zwamborn, A W

    1980-01-01

    A method employing a special computer for determining the internal diameters of blood vessels from photofluorographic image is described; in vitro and in vivo experiments are performed with the system. The amount of contrast medium injected is restricted to 4 times 3 ml, and it is possible to determine the diameter (in the range from 2 to 16 mm) at any place where blood vessels can be catheterized. In the in vivo experiments the maximum systematic error is +/-5 percent in the 7 to 8 mm range. PMID:7424549

  8. Blood pressure measurement and display system

    NASA Technical Reports Server (NTRS)

    Farkas, A. J.

    1972-01-01

    System is described that employs solid state circuitry to transmit visual display of patient's blood pressure. Response of sphygmomanometer cuff and microphone provide input signals. Signals and their amplitudes, from turn-on time to turn-off time, are continuously fed to data transmitter which transmits to display device.

  9. Reliable noninvasive measurement of blood gases

    DOEpatents

    Thomas, Edward V.; Robinson, Mark R.; Haaland, David M.; Alam, Mary K.

    1997-05-20

    This invention relates to methods and apparatus for, preferably, determining non-invasively and in vivo at least two of the five blood gas parameters (i.e., pH, [HCO.sub.3.sup.- ], PCO.sub.2, PO.sub.2, and O.sub.2 sat.) in a human.

  10. High-resolution breath-hold cardiac magnetic resonance imaging

    SciTech Connect

    Liu, Yu.

    1993-01-01

    This dissertation work is composed of investigations of three methods for fast cardiac magnetic resonance imaging (MRI). These methods include (1) 2D breath-hold magnetization prepared gradient echo and fast spin-echo (FSE) cardiac imaging, (2) 3D breath-hold magnetization prepared gradient echo cardiac imaging, and (3) real-time monitoring, feedback, and triggering for breath-hold MRI. The hypothesis of this work is that high resolution 2D and 3D magnetic resonance data sets for the heart can be acquired with the combination of magnetization prepared blood suppression for gradient echo techniques and accurate breath-holding methods. The 2D method included development of magnetic resonance data acquisition for cardiac imaging. The acquisition time is within a single breath-hold of 16 seconds (assuming heart 60/min). The data acquisition is synchronized with the electrocardiogram signal. Based on consistent observations of specific small cardiac structures like the papillary muscle, trabeculae, moderator band, and coronary vessels in studies of normal volunteers, the image quality represents a significant improvement over that obtained with fast imaging methods previously. To further improve the image quality provided by the 2D method, the first 3D cardiac MRI technique was developed. This method provides even better spatial resolution for cardiac images, with a voxel size of 1.09 [times] 2.19 [times] 4 mm[sup 3]. A 3D acquisition is completed in 8 breath-holds. The data acquisition for 3D cardiac imaging requires a consistent breath-hold position to avoid respiratory artifacts. To improve the reliability of the 3DFT acquisition, a new technique called MR breath-hold feedback was developed to provide reproducible breathholding. The diaphragm location is used as the index for breath-hold reproducibility measurement. The range of the diaphragm displacement in different breath-hold is reduced from 8.3 mm without the technique, to 1.3 mm with the technique.

  11. Blood Sugar Measurement in Zebrafish Reveals Dynamics of Glucose Homeostasis

    PubMed Central

    Eames, Stefani C.; Philipson, Louis H.; Prince, Victoria E.

    2010-01-01

    Abstract The adult zebrafish has the potential to become an important model for diabetes-related research. To realize this potential, small-scale methods for analyzing pancreas function are required. The measurement of blood glucose level is a commonly used method for assessing β-cell function, but the small size of the zebrafish presents challenges both for collecting blood samples and for measuring glucose. We have developed methods for collecting microsamples of whole blood and plasma for the measurement of hematocrit and blood glucose. We demonstrate that two hand-held glucose meters designed for use by human diabetics return valid results with zebrafish blood. Additionally, we present methods for fasting and for performing postprandial glucose and intraperitoneal glucose tolerance tests. We find that the dynamics of zebrafish blood glucose homeostasis are consistent with patterns reported for other omnivorous teleost fish. PMID:20515318

  12. The effect of adding CO2 to hypoxic inspired gas on cerebral blood flow velocity and breathing during incremental exercise.

    PubMed

    Fan, Jui-Lin; Kayser, Bengt

    2013-01-01

    Hypoxia increases the ventilatory response to exercise, which leads to hyperventilation-induced hypocapnia and subsequent reduction in cerebral blood flow (CBF). We studied the effects of adding CO2 to a hypoxic inspired gas on CBF during heavy exercise in an altitude naïve population. We hypothesized that augmented inspired CO2 and hypoxia would exert synergistic effects on increasing CBF during exercise, which would improve exercise capacity compared to hypocapnic hypoxia. We also examined the responsiveness of CO2 and O2 chemoreception on the regulation ventilation ([Formula: see text]E) during incremental exercise. We measured middle cerebral artery velocity (MCAv; index of CBF), [Formula: see text]E, end-tidal PCO2, respiratory compensation threshold (RC) and ventilatory response to exercise ([Formula: see text]E slope) in ten healthy men during incremental cycling to exhaustion in normoxia and hypoxia (FIO2 = 0.10) with and without augmenting the fraction of inspired CO2 (FICO2). During exercise in normoxia, augmenting FICO2 elevated MCAv throughout exercise and lowered both RC onset and[Formula: see text]E slope below RC (P<0.05). In hypoxia, MCAv and [Formula: see text]E slope below RC during exercise were elevated, while the onset of RC occurred at lower exercise intensity (P<0.05). Augmenting FICO2 in hypoxia increased [Formula: see text]E at RC (P<0.05) but no difference was observed in RC onset, MCAv, or [Formula: see text]E slope below RC (P>0.05). The [Formula: see text]E slope above RC was unchanged with either hypoxia or augmented FICO2 (P>0.05). We found augmenting FICO2 increased CBF during sub-maximal exercise in normoxia, but not in hypoxia, indicating that the 'normal' cerebrovascular response to hypercapnia is blunted during exercise in hypoxia, possibly due to an exhaustion of cerebral vasodilatory reserve. This finding may explain the lack of improvement of exercise capacity in hypoxia with augmented CO2. Our data further indicate that

  13. Bad Breath

    MedlinePlus

    ... mouth and between your teeth produce the bad odor. Other problems in your mouth, such as gum ... and medicines are associated with a specific breath odor. Having good dental habits, like brushing and flossing ...

  14. Bad Breath

    MedlinePlus

    ... hygiene leads to bad breath because when food particles are left in your mouth, they can rot ... Flossing once a day helps get rid of particles wedged between your teeth. Also, visit your dentist ...

  15. Breath sounds

    MedlinePlus

    The lung sounds are best heard with a stethoscope. This is called auscultation. Normal lung sounds occur ... the bottom of the rib cage. Using a stethoscope, the doctor may hear normal breathing sounds, decreased ...

  16. Measurement of Lung Phosphatidylcholines in Exhaled Breath Particles by a Convenient Collection Procedure.

    PubMed

    Ullah, Shahid; Sandqvist, Sören; Beck, Olof

    2015-11-17

    An analytical method based on high-performance liquid chromatography coupled to quadrupole tandem mass spectrometry was developed for the quantitative determination of four phosphatidylcholines (PCs) in human exhaled breath particles. Analytes were conveniently collected on an electrostatic polymer filter and extracted with methanol prior to analysis. Chromatographic separation was performed on an ultraperformance liquid chromatographic ethylene bridged hybrid phenyl column using a mobile phase consisting of water and methanol containing 4 mM ammonium formate and 0.1% ammonia. The mass spectrometer operated in positive electrospray ionization and selected reaction monitoring mode. Detection limits for PC 16:0/16:0 (dipalmitoylphosphatidylcholine, DPPC), PC 16:0/18:1, PC 16:0/18:2, and PC 18:0/18:2 were <0.01 ng/filter. Method recoveries at concentration levels of 0.1 and 10 ng/filter were 100-110% and 101-121%, respectively. Acceptable precision with coefficients of variation <20% and accuracies of 100% ± 20% were achieved. Identification of the individual PCs was performed on the basis of two product ions with correct ion ratios and chromatographic retention times. The highest amount in exhaled breath was found for DPPC with median concentration 1.14 ng/filter (range 0.6-21 ng/filter), and median molar ratios of DPPC/PC (16:0/18:1) of 1.98 (range 0.48-2.75). A different pattern with lower molar ratio (∼0.15) was found for oral fluid. The most significant element of this study was to use a precolumn in the LC system and to collecting exhaled particles in an electret polymer filter. Due to chromatographic interference by background contamination, an isolator column (PFC kit) was installed in between eluent mixer and injector to reduce contamination. This is the first LC/MS study where the method was successfully applied to analyze PCs in human exhaled breath by using a simple and convenient collection procedure. PMID:26505278

  17. Unilateral focal lesions in the rostrolateral medulla influence chemosensitivity and breathing measured during wakefulness, sleep, and exercise

    PubMed Central

    Morrell, M; Heywood, P; Moosavi, S; Guz, A; Stevens, J

    1999-01-01

    OBJECTIVES—The rostrolateral medulla (RLM) has been identified in animals as an important site of chemosensitivity; in humans such site(s) have not been defined. The aim of this study was to investigate the physiological implications of unilateral lesions in the lower brainstem on the control of breathing.
METHODS—In 15 patients breathing was measured awake at rest, asleep, during exercise, and during CO2 stimulation. The lesions were located clinically and by MRI; in nine patients they involved the RLM (RLM group), in six they were in the pons, cerebellum, or medial medulla (Non-RLM group). All RLM group patients, and three non-RLM group patients had ipsilateral Horner's syndrome.
RESULTS—Six of the RLM group had a ventilatory sensitivity to inhaled CO2 (V̇/PET CO2) below normal (group A: V̇/PET CO2, mean, 0.87; range 0.3-1.4 l.min-1/mm Hg). It was normal in all of the non-RLM group (group B: V̇/PET CO2, mean, 3.0; range, 2.6-3.9 min-1/mmHg). There was no significant difference in breathing between groups during relaxed wakefulness (V̇, group A: 7.44 (SD 2.5) l.min-1; group B: 6.02 (SD 1.3) l.min-1; PET CO2, group A: 41.0 (SD 4.2) mm g; group B: 38.3 (SD2.0) mm Hg) or during exercise (V̇/V̇O2: group A: 21 (SD 6.0) l.min-1/l.min-1; group B: 24 (SD 7.3) l.min-1/l.min-1). During sleep, all group A had fragmented sleep compared with only one patient in group B (group A: arousals, range 13 to >60 events/hour); moreover, in group A there was a high incidence of obstructive sleep apnoea associated with hypoxaemia.
CONCLUSION—Patients with unilateral RLM lesions require monitoring during sleep to diagnose any sleep apnoea. The finding that unilateral RLM lesions reduce ventilatory sensitivity to inhaled CO2 is consistent with animal studies. The reduced chemosensitivity had a minimal effect on breathing awake at rest or during exercise.

 PMID:10519871

  18. Continuous measurement of oxygen tensions in the air-breathing organ of Pacific tarpon (Megalops cyprinoides) in relation to aquatic hypoxia and exercise.

    PubMed

    Seymour, Roger S; Farrell, Anthony P; Christian, Keith; Clark, Timothy D; Bennett, Michael B; Wells, Rufus M G; Baldwin, John

    2007-07-01

    The Pacific tarpon is an elopomorph teleost fish with an air-breathing organ (ABO) derived from a physostomous gas bladder. Oxygen partial pressure (PO(2)) in the ABO was measured on juveniles (238 g) with fiber-optic sensors during exposure to selected aquatic PO(2) and swimming speeds. At slow speed (0.65 BL s(-1)), progressive aquatic hypoxia triggered the first breath at a mean PO(2) of 8.3 kPa. Below this, opercular movements declined sharply and visibly ceased in most fish below 6 kPa. At aquatic PO(2) of 6.1 kPa and swimming slowly, mean air-breathing frequency was 0.73 min(-1), ABO PO(2) was 10.9 kPa, breath volume was 23.8 ml kg(-1), rate of oxygen uptake from the ABO was 1.19 ml kg(-1) min(-1), and oxygen uptake per breath was 2.32 ml kg(-1). At the fastest experimental speed (2.4 BL s(-1)) at 6.1 kPa, ABO oxygen uptake increased to about 1.90 ml kg(-1) min(-1), through a variable combination of breathing frequency and oxygen uptake per breath. In normoxic water, tarpon rarely breathed air and apparently closed down ABO perfusion, indicated by a drop in ABO oxygen uptake rate to about 1% of that in hypoxic water. This occurred at a wide range of ABO PO(2) (1.7-26.4 kPa), suggesting that oxygen level in the ABO was not regulated by intrinsic receptors. PMID:17387483

  19. Thinking about breathing: Effects on respiratory sinus arrhythmia.

    PubMed

    Mortola, Jacopo P; Marghescu, Domnica; Siegrist-Johnstone, Rosemarie

    2016-03-01

    Respiratory sinus arrhythmia (RSA), the increase and decrease in instantaneous heart rate (HR) with inspiration and expiration, is commonly evaluated as function of breathing frequency f. However, to the extent that RSA plays a role in the efficiency of gas exchange, it may be expected to correlate better with HR/f ('breathing specific heart rate') than with f, because the former is a better reflection of the cardio-respiratory coupling. We measured RSA breath-by-breath in 209 young men and women during spontaneous breathing and during volitional breathing under auditory cues at vastly different f. In either case, and for both genders, RSA correlated better with HR/f than with f. As HR/f increased so did RSA, in a linear manner. When compared on the basis of HR/f, RSA did not differ significantly between spontaneous and volitional breathing. It is proposed that RSA is a central mechanism that ameliorates the matching between the quasi-continuous pulmonary blood flow and the intermittent airflow, irrespective of the type of ventilatory drive (cortical or autonomic). PMID:26724603

  20. Quantitative blood flux measurement using MUSIC

    NASA Astrophysics Data System (ADS)

    Yousefi, Siavash; Qin, Jia; Wang, Ruikang K.

    2014-03-01

    In this paper, we propose a method to quantify red blood cell (RBC) flow through capillary loops and microvessels using optical microangiography (OMAG). Current existing methods of capillary flow quantification either require a very long scanning time (~few minutes) or a large acquisition number per location (+100 scans per location) to form a highresolution spectral estimation. We utilize a model-based super-resolution spectral estimation technique based on principle of orthogonality to quantify moving RBCs within a voxel. The scanning protocol required for our method is very similar to 3D ultrahigh sensitive OMAG that requires few scans per location (8) and can be performed in few seconds that makes it applicable for in vivo experiments. This method is analogous to power Doppler in ultrasonography and estimates the number of red blood cells passing through the beam as opposed to the velocity of the particles. The technique is tested both qualitatively and quantitatively by using OMAG to image microcirculation within mouse ear flap in vivo.

  1. Optoacoustic measurements of human placenta and umbilical blood oxygenation

    NASA Astrophysics Data System (ADS)

    Nanovskaya, T. N.; Petrov, I. Y.; Petrov, Y.; Patrikeeva, S. L.; Ahmed, M. S.; Hankins, G. D. V.; Prough, D. S.; Esenaliev, R. O.

    2016-03-01

    Adequate oxygenation is essential for normal embryogenesis and fetal growth. Perturbations in the intrauterine oxidative environment during pregnancy are associated with several pathophysiological disorders such as pregnancy loss, preeclampsia, and intrauterine growth restriction. We proposed to use optoacoustic technology for monitoring placental and fetal umbilical blood oxygenation. In this work, we studied optoacoustic monitoring of oxygenation in placenta and umbilical cord blood ex vivo using technique of placenta perfusion. We used a medical grade, nearinfrared, tunable, optoacoustic system developed and built for oxygenation monitoring in blood vessels and in tissues. First, we calibrated the system for cord blood oxygenation measurements by using a CO-Oximeter (gold standard). Then we performed validation in cord blood circulating through the catheters localized on the fetal side of an isolated placental lobule. Finally, the oxygenation measurements were performed in the perfused placental tissue. To increase or decrease blood oxygenation, we used infusion of a gas mixture of 95% O2 + 5% CO2 and 95% N2 + 5% CO2, respectively. In placental tissue, up to four cycles of changes in oxygenation were performed. The optoacoustically measured oxygenation in circulating cord blood and in placental lobule closely correlated with the actual oxygenation data measured by CO-Oximeter. We plan to further test the placental and cord blood oxygenation monitoring with optoacoustics in animal and clinical studies.

  2. How to breathe when you are short of breath

    MedlinePlus

    Pursed lip breathing; COPD - pursed lip breathing; Emphysema - pursed lip breathing; Chronic bronchitis - pursed lip breathing; Pulmonary fibrosis - pursed lip breathing; Interstitial lung disease - pursed lip breathing; Hypoxia - pursed lip breathing; ...

  3. Negative pressure breathing increases cardiac output and nitrogen elimination in seated subjects.

    PubMed

    Lundgren, Claes E G; Eckhardt, Lukas G; Senf, Curtis J; Bowdwin, Melina R; Pendergast, David R

    2013-01-01

    During denitrogenation for rescue, crew members of an internally pressurized disabled submarine (DISSUB) must sit upright, which may hamper venous return, cardiac output and peripheral circulation. Since negative pressure breathing (NPB) might counteract this problem, denitrogenation was measured in sitting subjects performing NPB. Seven male subjects completed 125-minute nitrogen (N2) washouts breathing either 100% oxygen (O2) or a normoxic gas (21% O2 in argon) in control conditions and intermittent (I: inspirations only) or continuous (C) NPB at -10 or -15 cmH2O. N2 elimination was measured using a closed rebreathing system. INPB (intermittent) (-15cmH2O) and CNPB (continous breathing) (-10 and -15cmH2O) increased cardiac output (CO) 9% during both O2 and normoxic breathing. Systolic and diastolic blood pressures were unaffected by the CO increase, suggesting a peripheral vasodilatation and enhanced tissue perfusion leading to increased N2 elimination. With the CO boost, N2 washout increased 6% breathing O2 at -15 cmH2O CNPB and INPB, while during normoxic breathing there were 6% and 12% increases due to CNBP, -10 and -15 respectively and 6% with -15cmH2O INPB; breathing 100% O2 yielding 5% to 15% less N2 washout than normoxic breathing. Negative pressure breathing during denitrogenation may facilitate decompression in divers and in crew members being rescued from a DISSUB. PMID:24224284

  4. Automated measurement of retinal blood vessel tortuosity

    NASA Astrophysics Data System (ADS)

    Joshi, Vinayak; Reinhardt, Joseph M.; Abramoff, Michael D.

    2010-03-01

    Abnormalities in the vascular pattern of the retina are associated with retinal diseases and are also risk factors for systemic diseases, especially cardiovascular diseases. The three-dimensional retinal vascular pattern is mostly formed congenitally, but is then modified over life, in response to aging, vessel wall dystrophies and long term changes in blood flow and pressure. A characteristic of the vascular pattern that is appreciated by clinicians is vascular tortuosity, i.e. how curved or kinked a blood vessel, either vein or artery, appears along its course. We developed a new quantitative metric for vascular tortuosity, based on the vessel's angle of curvature, length of the curved vessel over its chord length (arc to chord ratio), number of curvature sign changes, and combined these into a unidimensional metric, Tortuosity Index (TI). In comparison to other published methods this method can estimate appropriate TI for vessels with constant curvature sign and vessels with equal arc to chord ratios, as well. We applied this method to a dataset of 15 digital fundus images of 8 patients with Facioscapulohumeral muscular dystrophy (FSHD), and to the other publically available dataset of 60 fundus images of normal cases and patients with hypertensive retinopathy, of which the arterial and venous tortuosities have also been graded by masked experts (ophthalmologists). The method produced exactly the same rank-ordered list of vessel tortuosity (TI) values as obtained by averaging the tortuosity grading given by 3 ophthalmologists for FSHD dataset and a list of TI values with high ranking correlation with the ophthalmologist's grading for the other dataset. Our results show that TI has potential to detect and evaluate abnormal retinal vascular structure in early diagnosis and prognosis of retinopathies.

  5. Breathing difficulty - lying down

    MedlinePlus

    ... breath; Paroxysmal nocturnal dyspnea; PND; Difficulty breathing while lying down; Orthopnea ... Obesity (does not directly cause difficulty breathing while lying down but often worsens other conditions that lead ...

  6. [Comparison of invasive blood pressure measurement in the aorta with indirect oscillometric blood pressure measurement at the wrist and forearm].

    PubMed

    Saul, F; Aristidou, Y; Klaus, D; Wiemeyer, A; Lösse, B

    1995-09-01

    Indirectly measured blood pressure at the wrist or upper arm was compared with directly measured values in the aortic arch during routinely performed diagnostic cardiac catheterization in 100 patients (31-80 years, mean 59.3 years, 60% males). The noninvasive measurements were carried out by oscillometric devices, NAiS Blood Pressure Watch for measurements at the wrist, and Hestia OZ80 at the upper arm. Systolic blood pressure measured at the wrist was 4.3 +/- 14.1 mm Hg, and the diastolic value 6.0 +/- 8.9 mm Hg higher than when measured at the aortic arch; the difference was significant in both cases. Correlation coefficients were 0.85 for systolic and 0.71 for diastolic blood pressure. In 16% of the patients the systolic blood pressure at the wrist differed more than +/- 20 mm Hg. The diastolic blood pressure at the wrist measured more than +/- 20 mm Hg higher than in the aorta in 5% of the patients. At the upper arm mean systolic values were not different to the aorta. The diastolic pressure was 9.3 +/- 9.8 mm Hg higher in the aorta than at the upper arm. To verify the accuracy of values measured with the NAiS Blood Pressure Watch compared with the standard technique at the upper arm, sequential measurements were made at wrist and ipsilateral upper arm in the same group of 100 patients. The systolic blood pressure at the left wrist was 3.4 +/- 13.3 mm Hg higher and the diastolic pressure 3.8 +/- 9.5 mm Hg lower than at the upper arm. Only 53% of systolic values lay within a range of +/- 10 mm Hg. The correspondence between wrist and upper arm values was better for diastolic blood pressure, the values differing by less than +/- 10 mm Hg in two-thirds of patients. Self-measurement of arterial blood pressure with an oscillometric device at the wrist can be recommended only in individual cases with a difference of simultaneously measured values at the upper arm of less than +/- 10 mm Hg for systolic and diastolic blood pressures. The standard method for indirectly

  7. Automated analysis of blood pressure measurements (Korotkov sound)

    NASA Technical Reports Server (NTRS)

    Golden, D. P.; Hoffler, G. W.; Wolthuis, R. A.

    1972-01-01

    Automatic system for noninvasive measurements of arterial blood pressure is described. System uses Korotkov sound processor logic ratios to identify Korotkov sounds. Schematic diagram of system is provided to show components and method of operation.

  8. Blood-flow measurement in muscle with Xe-133

    SciTech Connect

    Chung, S.Y.; Kim, I.; Ryo, U.Y.; Maskin, C.; Pinsky, S.

    1987-11-01

    An alternative method to the conventional miniature probe system for the measurement of blood flow in muscle has been developed. Xenon-133 was injected into the quadriceps muscles of ten subjects. A gamma camera and an online computer were then used to measure the half-clearance time of the Xe-133 while the subject was both at rest and exercising on an upright bicycle ergometer. The blood flow in the muscle was then calculated from the acquired data.

  9. Measurement and Comparison of Organic Compound Concentrations in Plasma, Whole Blood, and Dried Blood Spot Samples

    PubMed Central

    Batterman, Stuart A.; Chernyak, Sergey; Su, Feng-Chiao

    2016-01-01

    The preferred sampling medium for measuring human exposures of persistent organic compounds (POPs) is blood, and relevant sample types include whole blood, plasma, and dried blood spots (DBS). Because information regarding the performance and comparability of measurements across these sample types is limited, it is difficult to compare across studies. This study evaluates the performance of POP measurements in plasma, whole blood and DBS, and presents the distribution coefficients needed to convert concentrations among the three sample types. Blood samples were collected from adult volunteers, along with demographic and smoking information, and analyzed by GC/MS for organochlorine pesticides (OCPs), chlorinated hydrocarbons (CHCs), polychlorinated biphenyls (PCBs), and brominated diphenyl ethers (PBDEs). Regression models were used to evaluate the relationships between the sample types and possible effects of personal covariates. Distribution coefficients also were calculated using physically-based models. Across all compounds, concentrations in plasma were consistently the highest; concentrations in whole blood and DBS samples were comparable. Distribution coefficients for plasma to whole blood concentrations ranged from 1.74 to 2.26 for pesticides/CHCs, averaged 1.69 ± 0.06 for the PCBs, and averaged 1.65 ± 0.03 for the PBDEs. Regression models closely fit most chemicals (R2 > 0.80), and whole blood and DBS samples generally showed very good agreement. Distribution coefficients estimated using biologically-based models were near one and did not explain the observed distribution. Among the study population, median concentrations of several pesticides/CHCs and PBDEs exceeded levels reported in the 2007–2008 National Health and Nutrition Examination Survey, while levels of other OCPs and PBDEs were comparable or lower. Race and smoking status appeared to slightly affect plasma/blood concentration ratios for several POPs. The experimentally

  10. Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging

    NASA Astrophysics Data System (ADS)

    Werkmeister, René M.; Vietauer, Martin; Knopf, Corinna; Fürnsinn, Clemens; Leitgeb, Rainer A.; Reitsamer, Herbert; Gröschl, Martin; Garhöfer, Gerhard; Vilser, Walthard; Schmetterer, Leopold

    2014-10-01

    A wide variety of ocular diseases are associated with abnormalities in ocular circulation. As such, there is considerable interest in techniques for quantifying retinal blood flow, among which Doppler optical coherence tomography (OCT) may be the most promising. We present an approach to measure retinal blood flow in the rat using a new optical system that combines the measurement of blood flow velocities via Doppler Fourier-domain optical coherence tomography and the measurement of vessel diameters using a fundus camera-based technique. Relying on fundus images for extraction of retinal vessel diameters instead of OCT images improves the reliability of the technique. The system was operated with an 841-nm superluminescent diode and a charge-coupled device camera that could be operated at a line rate of 20 kHz. We show that the system is capable of quantifying the response of 100% oxygen breathing on the retinal blood flow. In six rats, we observed a decrease in retinal vessel diameters of 13.2% and a decrease in retinal blood velocity of 42.6%, leading to a decrease in retinal blood flow of 56.7%. Furthermore, in four rats, the response of retinal blood flow during stimulation with diffuse flicker light was assessed. Retinal vessel diameter and blood velocity increased by 3.4% and 28.1%, respectively, leading to a relative increase in blood flow of 36.2%;. The presented technique shows much promise to quantify early changes in retinal blood flow during provocation with various stimuli in rodent models of ocular diseases in rats.

  11. Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging.

    PubMed

    Werkmeister, René M; Vietauer, Martin; Knopf, Corinna; Fürnsinn, Clemens; Leitgeb, Rainer A; Reitsamer, Herbert; Gröschl, Martin; Garhöfer, Gerhard; Vilser, Walthard; Schmetterer, Leopold

    2014-01-01

    A wide variety of ocular diseases are associated with abnormalities in ocular circulation. As such, there is considerable interest in techniques for quantifying retinal blood flow, among which Doppler optical coherence tomography (OCT) may be the most promising. We present an approach to measure retinal blood flow in the rat using a new optical system that combines the measurement of blood flow velocities via Doppler Fourier-domain optical coherence tomography and the measurement of vessel diameters using a fundus camera-based technique. Relying on fundus images for extraction of retinal vessel diameters instead of OCT images improves the reliability of the technique. The system was operated with an 841-nm superluminescent diode and a charge-coupled device camera that could be operated at a line rate of 20 kHz. We show that the system is capable of quantifying the response of 100% oxygen breathing on the retinal blood flow. In six rats, we observed a decrease in retinal vessel diameters of 13.2% and a decrease in retinal blood velocity of 42.6%, leading to a decrease in retinal blood flow of 56.7%. Furthermore, in four rats, the response of retinal blood flow during stimulation with diffuse flicker light was assessed. Retinal vessel diameter and blood velocity increased by 3.4% and 28.1%, respectively, leading to a relative increase in blood flow of 36.2%. The presented technique shows much promise to quantify early changes in retinal blood flow during provocation with various stimuli in rodent models of ocular diseases in rats. PMID:25321400

  12. Metabolic breath analyzer

    NASA Technical Reports Server (NTRS)

    Perry, C. L.

    1971-01-01

    Instrument measures metabolic breathing rate and dynamics of human beings in atmospheres ranging from normal air to 100 percent oxygen at ambient pressures from 14.7 to 3.0 psia. Measurements are made at rest or performing tasks up to maximum physical capacity under either zero or normal gravity.

  13. Measuring tissue blood flow using ultrasound modulated diffused light

    NASA Astrophysics Data System (ADS)

    Ron, A.; Racheli, N.; Breskin, I.; Metzger, Y.; Silman, Z.; Kamar, M.; Nini, A.; Shechter, R.; Balberg, M.

    2012-02-01

    We demonstrate the ability of a novel device employing ultrasound modulation of near infrared light (referred as "Ultrasound tagged light" or UTL) to perform non-invasive monitoring of blood flow in the microvascular level in tissue. Monitoring microcirculatory blood flow is critical in clinical situations affecting flow to different organs, such as the brain or the limbs. . However, currently there are no non-invasive devices that measure microcirculatory blood flow in deep tissue continuously. Our prototype device (Ornim Medical, Israel) was used to monitor tissue blood flow on anesthetized swine during controlled manipulations of increased and decreased blood flow. Measurements were done on the calf muscle and forehead of the animal and compared with Laser Doppler (LD). ROC analysis of the sensitivity and specificity for detecting an increase in blood flow on the calf muscle, demonstrated AUC = 0.951 for 23 systemic manipulations of cardiac output by Epinephrine injection, which is comparable to AUC = 0.943 using laser Doppler. Some examples of cerebral blood flow monitoring are presented, along with their individual ROC curves. UTL flowmetry is shown to be effective in detecting changes in cerebral and muscle blood flow in swine, and has merit in clinical applications.

  14. Breath Ketone Testing: A New Biomarker for Diagnosis and Therapeutic Monitoring of Diabetic Ketosis

    PubMed Central

    Qiao, Yue; Gao, Zhaohua; Liu, Yong; Cheng, Yan; Yu, Mengxiao; Zhao, Lingling

    2014-01-01

    Background. Acetone, β-hydroxybutyric acid, and acetoacetic acid are three types of ketone body that may be found in the breath, blood, and urine. Detecting altered concentrations of ketones in the breath, blood, and urine is crucial for the diagnosis and treatment of diabetic ketosis. The aim of this study was to evaluate the advantages of different detection methods for ketones, and to establish whether detection of the concentration of ketones in the breath is an effective and practical technique. Methods. We measured the concentrations of acetone in the breath using gas chromatography-mass spectrometry and β-hydroxybutyrate in fingertip blood collected from 99 patients with diabetes assigned to groups 1 (−), 2 (±), 3 (+), 4 (++), or 5 (+++) according to urinary ketone concentrations. Results. There were strong relationships between fasting blood glucose, age, and diabetic ketosis. Exhaled acetone concentration significantly correlated with concentrations of fasting blood glucose, ketones in the blood and urine, LDL-C, creatinine, and blood urea nitrogen. Conclusions. Breath testing for ketones has a high sensitivity and specificity and appears to be a noninvasive, convenient, and repeatable method for the diagnosis and therapeutic monitoring of diabetic ketosis. PMID:24900994

  15. Traveling with breathing problems

    MedlinePlus

    If you have breathing problems and you: Are short of breath most of the time Get short of breath when you walk 150 ... or less Have been in the hospital for breathing problems recently Use oxygen at home, even if ...

  16. Surfacers change their dive tactics depending on the aim of the dive: evidence from simultaneous measurements of breaths and energy expenditure.

    PubMed

    Okuyama, Junichi; Tabata, Runa; Nakajima, Kana; Arai, Nobuaki; Kobayashi, Masato; Kagawa, Shiro

    2014-11-22

    Air-breathing divers are assumed to have evolved to apportion their time between surface and underwater periods to maximize the benefit gained from diving activities. However, whether they change their time allocation depending on the aim of the dive is still unknown. This may be particularly crucial for 'surfacers' because they dive for various purposes in addition to foraging. In this study, we counted breath events at the surface and estimated oxygen consumption during resting, foraging and other dives in 11 green turtles (Chelonia mydas) in the wild. Breath events were counted by a head-mounted acceleration logger or direct observation based on an animal-borne video logger, and oxygen consumption was estimated by measuring overall dynamic body acceleration. Our results indicate that green turtles maximized their submerged time, following this with five to seven breaths to replenish oxygen for resting dives. However, they changed their dive tactic during foraging and other dives; they surfaced without depleting their estimated stores of oxygen, followed by only a few breaths for effective foraging and locomotion. These dichotomous surfacing tactics would be the result of behavioural modifications by turtles depending on the aim of each dive. PMID:25297856

  17. Surfacers change their dive tactics depending on the aim of the dive: evidence from simultaneous measurements of breaths and energy expenditure

    PubMed Central

    Okuyama, Junichi; Tabata, Runa; Nakajima, Kana; Arai, Nobuaki; Kobayashi, Masato; Kagawa, Shiro

    2014-01-01

    Air-breathing divers are assumed to have evolved to apportion their time between surface and underwater periods to maximize the benefit gained from diving activities. However, whether they change their time allocation depending on the aim of the dive is still unknown. This may be particularly crucial for ‘surfacers’ because they dive for various purposes in addition to foraging. In this study, we counted breath events at the surface and estimated oxygen consumption during resting, foraging and other dives in 11 green turtles (Chelonia mydas) in the wild. Breath events were counted by a head-mounted acceleration logger or direct observation based on an animal-borne video logger, and oxygen consumption was estimated by measuring overall dynamic body acceleration. Our results indicate that green turtles maximized their submerged time, following this with five to seven breaths to replenish oxygen for resting dives. However, they changed their dive tactic during foraging and other dives; they surfaced without depleting their estimated stores of oxygen, followed by only a few breaths for effective foraging and locomotion. These dichotomous surfacing tactics would be the result of behavioural modifications by turtles depending on the aim of each dive. PMID:25297856

  18. Peripheral vascular effects on auscultatory blood pressure measurement.

    PubMed

    Rabbany, S Y; Drzewiecki, G M; Noordergraaf, A

    1993-01-01

    Experiments were conducted to examine the accuracy of the conventional auscultatory method of blood pressure measurement. The influence of the physiologic state of the vascular system in the forearm distal to the site of Korotkoff sound recording and its impact on the precision of the measured blood pressure is discussed. The peripheral resistance in the arm distal to the cuff was changed noninvasively by heating and cooling effects and by induction of reactive hyperemia. All interventions were preceded by an investigation of their effect on central blood pressure to distinguish local effects from changes in central blood pressure. These interventions were sufficiently moderate to make their effect on central blood pressure, recorded in the other arm, statistically insignificant (i.e., changes in systolic [p < 0.3] and diastolic [p < 0.02]). Nevertheless, such alterations were found to modify the amplitude of the Korotkoff sound, which can manifest itself as an apparent change in arterial blood pressure that is readily discerned by the human ear. The increase in diastolic pressure for the cooling experiments was statistically significant (p < 0.001). Moreover, both measured systolic (p < 0.004) and diastolic (p < 0.001) pressure decreases during the reactive hyperemia experiments were statistically significant. The findings demonstrate that alteration in vascular state generates perplexing changes in blood pressure, hence confirming experimental observations by earlier investigators as well as predictions by our model studies. PMID:8463815

  19. Finger temperature controller for non-invasive blood glucose measurement

    NASA Astrophysics Data System (ADS)

    Zhang, Xiqin; Ting, Choon Meng; Yeo, Joon Hock

    2010-11-01

    Blood glucose level is an important parameter for doctors to diagnose and treat diabetes. The Near-Infra-Red (NIR) spectroscopy method is the most promising approach and this involves measurement on the body skin. However it is noted that the skin temperature does fluctuate with the environmental and physiological conditions and we found that temperature has important influences on the glucose measurement. In-vitro and in-vivo investigations on the temperature influence on blood glucose measurement have been carried out. The in-vitro results show that water temperature has significant influence on water absorption. Since 90% of blood components are water, skin temperature of measurement site has significant influence on blood glucose measurement. Also the skin temperature is related to the blood volume, blood volume inside capillary vessels changes with skin temperature. In this paper the relationship of skin temperature and signal from the skin and inside tissue was studied at different finger temperatures. Our OGTT (oral glucose tolerance test) trials results show the laser signals follow the skin temperature trend and the correlation of signal and skin temperature is much stronger than the correlation of signal and glucose concentration. A finger heater device is designed to heat and maintain the skin temperature of measurement site. The heater is controlled by an electronic circuit according to the skin temperature sensed by a thermocouple that is put close to the measurement site. In vivo trials were carried out and the results show that the skin temperature significantly influences the signal fluctuations caused by pulsate blood and the average signal value.

  20. Shot-noise Limited Faraday Rotation Spectroscopy for Detection of Nitric Oxide Isotopes in Breath, Urine, and Blood

    NASA Astrophysics Data System (ADS)

    Wang, Yin; Nikodem, Michal; Zhang, Eric; Cikach, Frank; Barnes, Jarrod; Comhair, Suzy; Dweik, Raed A.; Kao, Christina; Wysocki, Gerard

    2015-03-01

    Measurement of NO and/or its metabolites in the various body compartments has transformed our understanding of biology. The inability of the current NO measurement methods to account for naturally occurring and experimental NO isotopes, however, has prevented the scientific community from fully understating NO metabolism in vivo. Here we present a mid-IR Faraday rotation spectrometer (FRS) for detection of NO isotopes. The instrument utilizes a novel dual modulation/demodulation (DM) FRS method which exhibits noise performance at only 2 times the fundamental quantum shot-noise level and provides the record sensitivity in its class. This is achieved with a system that is fully autonomous, robust, transportable, and does not require cryogenic cooling. The DM-FRS enables continuous monitoring of nitric oxide isotopes with the detection limits of 3.72 ppbv/Hz1/2 to14NO and 0.53 ppbv/Hz1/2 to15NO using only 45 cm active optical path. This DM-FRS measurement method can be used to improve the performance of conventional FRS sensors targeting other radical species. The feasibility of the instrument to perform measurements relevant to studies of NO metabolism in humans is demonstrated.

  1. Shot-noise Limited Faraday Rotation Spectroscopy for Detection of Nitric Oxide Isotopes in Breath, Urine, and Blood

    PubMed Central

    Wang, Yin; Nikodem, Michal; Zhang, Eric; Cikach, Frank; Barnes, Jarrod; Comhair, Suzy; Dweik, Raed A.; Kao, Christina; Wysocki, Gerard

    2015-01-01

    Measurement of NO and/or its metabolites in the various body compartments has transformed our understanding of biology. The inability of the current NO measurement methods to account for naturally occurring and experimental NO isotopes, however, has prevented the scientific community from fully understating NO metabolism in vivo. Here we present a mid-IR Faraday rotation spectrometer (FRS) for detection of NO isotopes. The instrument utilizes a novel dual modulation/demodulation (DM) FRS method which exhibits noise performance at only 2 times the fundamental quantum shot-noise level and provides the record sensitivity in its class. This is achieved with a system that is fully autonomous, robust, transportable, and does not require cryogenic cooling. The DM-FRS enables continuous monitoring of nitric oxide isotopes with the detection limits of 3.72 ppbv/Hz1/2 to14NO and 0.53 ppbv/Hz1/2 to15NO using only 45 cm active optical path. This DM-FRS measurement method can be used to improve the performance of conventional FRS sensors targeting other radical species. The feasibility of the instrument to perform measurements relevant to studies of NO metabolism in humans is demonstrated. PMID:25767064

  2. Easy-to-use blood velocity measurement instruments

    NASA Astrophysics Data System (ADS)

    Vilkomerson, David H. R.; Chilipka, Thomas

    2003-05-01

    This paper describes a new kind of clinical instrument designed to allow non-specialists to quantitatively measure blood velocity. The instrument's design utilizes vector continuous-wave (CW) Doppler. Vector CW Doppler insonates a volume with simultaneous multiple-angle beams that define a measurement region; within that region, the velocity vector of the blood can be measured independently of the probe orientation. By eliminating the need for simultaneous imaging and the specially trained technician required for the complicated instrument needed for such imaging, easy and inexpensive blood velocity measurements becomes possible. A prototype for a CW vector Doppler instrument has been used to measure blood velocity in several clinically important arteries: the radial and ulnar in the arm, the femoral in the leg, and the carotid in the neck. We report here on its first clinical use -- monitoring the flow in dialysis access grafts to prevent graft thrombosis. These early clinical results show accuracy and rapid learning of proper instrument use. The design approach presented shows much promise in creating instruments that will provide simple and low-cost-of-use procedures for measurement of blood velocity.

  3. Temperature influence on non-invasive blood glucose measurement

    NASA Astrophysics Data System (ADS)

    Zhang, Xiqin; Yeo, Joon Hock

    2009-02-01

    Regular monitoring of blood sugar level is important for the management of diabetes. The Near-Infra-Red (NIR) spectroscopy method is a promising approach and this involves some form of contact with the body skin. It is noted that the skin temperature does fluctuate with the environment and physiological conditions and the temperature has an influence on the glucose measurement. In this paper, in-vitro and in-vivo investigations on the temperature influence on blood glucose measurement were studied. The in-vitro results from FTIR spectrometer show that sample temperature has significant influence on water absorption, which significantly affects the glucose absorption measurement. The in-vivo results show that when skin temperature around the measurement site is taken into consideration, the prediction of blood glucose level greatly improves.

  4. Measurement of directed blood flow by laser speckle

    NASA Astrophysics Data System (ADS)

    Hirst, Evan R.; Thompson, Oliver B.; Andrews, Michael K.

    2011-03-01

    Recent success in reconciling laser Doppler and speckle measurements of dermal perfusion by the use of multi-exposure speckle has prompted an investigation of speckle effects arising from directed blood flow which might be expected in the small blood vessels of the eye. Unlike dermal scatter, the blood in retinal vessels is surrounded by few small and stationary scatterers able to assist the return of light energy by large-angle scatter. Returning light is expected to come from multiple small angle scatter from the large red blood cells which dominate the fluid. This work compares speckle measurements on highly scattering skin, with measurements on flow in a retinal phantom consisting of a glass capillary which is itself immersed in an index matching fluid to provide a flat air-phantom interface. Brownian motion dominated measurements when small easily levitated scatters were used, and flow was undetectable. With whole-blood, Brownian motion was small and directed flows in the expected region of tens of mm/s were detectable. The nominal flow speed relates to the known pump rate; within the capillary the flow will have a profile reducing toward the walls. The pulsatile effects on laser speckle contrast in the retina are discussed with preliminary multi-exposure measurements on retinal vessels using a fundus camera. Differences between the multiple exposure curves and power spectra of perfused tissue and ordered flow are discussed.

  5. Measuring Arterial Blood Pressure. A Self-Contained Instructional Module.

    ERIC Educational Resources Information Center

    Schultz, Chris Ellen

    This self-contained instructional module is designed to help adult caregivers learn how to measure arterial blood pressure in the home. The module includes the following parts: objectives; pretest (with answers); four sections of instructional material covering (1) equipment, (2) cuff placement and locating the brachial artery, (3) measuring blood…

  6. Application of end-expired breath sampling to estimate carboxyhemoglobin levels in community air pollution exposure assessments

    NASA Astrophysics Data System (ADS)

    Lambert, William E.; Colome, Steven D.; Wojciechowski, Sandra L.

    Measurement of carbon monoxide (CO) in end-expired air after breath-holding permits the estimation of blood carboxyhemoglobin (COHb) levels. Some literature suggests that the precision of the method decreases at low COHb levels. As part of a community exposure and health study, the end-expired breath method was applied to estimate COHb levels in 28 men with ischemic heart disease. Paired samples of blood and breath were collected at the beginning and end of the 24-h CO monitoring periods. The aggregate regression of all subjects' COHb on breath CO displayed high variability. However, the variability was substantially reduced for any particular subject, promoting the use of individualized blood-breath standard curves to improve the precision of COHb estimates made from breath CO. The ultimate accuracy of the blood-breath relationship could not be resolved by our data. Two major sources of error are identified. The observed person-to-person variability may be caused by physiologic factors or differences in ability to deliver an end-expired breath sample representative of alveolar air. This variation may also be due to instrumentation factors, specifically the accuracy of the IL282 CO-Oximeter at 0-3% levels. Further research into the sources of variability in the end-expired breath method is recommended. Epidemiologists using similar end-expired breath measurements to predict COHb levels should be cognizant of the magnitude and probable direction of the error in COHb estimates. This non-invasive method should continue to allow evaluation of the success of personal monitoring efforts and pharmacokinetic modeling of CO uptake in community exposure research.

  7. Blood oxygenation level-dependent magnetic resonance imaging during carbogen breathing: differentiation between prostate cancer and benign prostate hyperplasia and correlation with vessel maturity

    PubMed Central

    Di, Ningning; Mao, Ning; Cheng, Wenna; Pang, Haopeng; Ren, Yan; Wang, Ning; Liu, Xinjiang; Wang, Bin

    2016-01-01

    Objective The aim of this study was to investigate whether the blood oxygenation level-dependent (BOLD) contrast magnetic resonance imaging (MRI) can evaluate tumor maturity and preoperatively differentiate prostate cancer (PCa) from benign prostate hyperplasia (BPH). Patients and methods BOLD MRI based on transverse relaxation time*-weighted echo planar imaging was performed to assess PCa (19) and BPH (22) responses to carbogen (95% O2 and 5% CO2). The average signal values of PCa and BPH before and after carbogen breathing and the relative increased signal values were computed, respectively. The endothelial-cell marker, CD31, and the pericyte marker, α-smooth muscle actin (mature vessels), were detected with immunofluorescence, and were assessed by microvessel density (MVD) and microvessel pericyte density (MPD). The microvessel pericyte coverage index (MPI) was used to evaluate the degree of vascular maturity. The changed signal from BOLD MRI was correlated with MVD, MPD, and MPI. Results After inhaling carbogen, both PCa and BPH showed an increased signal, but a lower slope was found in PCa than that in BPH (P<0.05). PCa had a higher MPD and MVD but a lower MPI than BPH. The increased signal intensity was positively correlated with MPI in PCa and that in BPH (r=0.616, P=0.011; r=0.658, P=0.002); however, there was no correlation between the increased signal intensity and MPD or MVD in PCa than that in BPH (P>0.05). Conclusion Our results confirmed that the increased signal values induced by BOLD MRI well differentiated PCa from BPH and had a positive correlation with vessel maturity in both of them. BOLD MRI can be utilized as a surrogate marker for the noninvasive assessment of the degree of vessel maturity. PMID:27462169

  8. Superiority of home blood pressure measurements over office measurements for testing antihypertensive drugs.

    PubMed

    Vaur; Dubroca; Dutrey-Dupagne; Genès; Chatellier; Bouvier-d'Yvoire; Elkik; Ménard

    1998-04-01

    OBJECTIVE: To compare the effects on office blood pressure and home blood pressure of placebo and active drug administration. DESIGN: After a 2-week wash-out period, patients with mild-to-moderate hypertension entered a 2-week single-blind placebo period and then a 4-week double-blind period. Patients were randomly assigned to be administered either 2 mg trandolapril once daily or its placebo in a 2:1 proportion. Office blood pressure was measured by a physician at the end of each period, using a mercury sphygmomanometer (mean of three consecutive measurements). Home blood pressure was measured during the last week of each period according to standard procedure carefully taught to each patient by the physician. Compliance was checked by using electronic pill boxes. RESULTS: Data for 34 of the 44 patients who entered the study were eligible for analysis. Baseline systolic blood pressure/diastolic blood pressure were significantly (P = 0.0001/P = 0.0001) higher for office blood pressure (161/101 mmHg) than they were for home blood pressure (145/93 mmHg). There was no statistically significant difference between the placebo and active-treatment groups at baseline. During the single-blind period, blood pressures measured at the office and at home did not change significantly. Office blood pressure decreased by 2.7 +/- 10 mmHg for systolic blood pressure and by 0.5 +/- 4 mmHg for diastolic blood pressure whereas home blood pressure increased by 0.8 +/- 6 mmHg for systolic blood pressure and by 0.7 +/- 4 mmHg for diastolic blood pressure. During the double-blind period, office blood pressure fell significantly with trandolapril treatment (systolic by 10.2 +/- 12 mmHg, diastolic by 8.3 +/- 6 mmHg; P = 0.0005/0.0001, versus single-blind placebo period) but this decrease was not significantly different (P = 0.45/0.92) from the fall in members of the placebo group (systolic by 6.9 +/- 9 mmHg, diastolic by 8.0 +/-6 mmHg; P = 0.04/0.002, versus single-blind placebo period

  9. Microprobes For Blood Flow Measurements In Tissue And Small Vessels

    NASA Astrophysics Data System (ADS)

    Oberg, P. A.; Salerud, E. G.

    1988-04-01

    Laser Doppler flowmetry is a method for the continuous and non-invasive recording of tissue blood flow. The method has already proved to be advantageous in a number of clinical as well as theoretical medical disciplines. In dermatology, plastic- and gastrointestinal surgery laser Doppler measurements have substantially contributed to increase knowledge of microvascular perfusion. In experimental medicine, the method has been used in the study of a great variety of microvascular problems. Spontaneous rhythmical variations, spatial and temporal fluctuations in human skin blood flow are mentioned as examples of problem areas in which new knowledge has been generated. The method has facilitated further investigations of the nature of spongeous bone blood flow, testis and kidney cortex blood flow. Recently we have showed that a variant of the laser Doppler method principle, using a single optical fiber, can be advantageous in deep tissue measurements. With this method laser light is transmitted bidirectionally in a single fiber. The tissue trauma which affects blood flow can be minimized by introducing small diameter fibers (0.1-0.5 mm). A special set-up utilizing the same basic principle has been used for the recording of blood flow in small vessels.

  10. The blood beat measurement with near infrared ray

    NASA Astrophysics Data System (ADS)

    Oshiro, Osamu; Horio, Hideyuki; Masuda, Yasushi

    This paper describes the blood beat measurement system with near infra-red ray. A blood vessel was captured sequentially with a CCD camera, an near infra-red LED and an optical filter. In order to extract a blood vessel portion from each captured image, binarization processing was performed using the threshold on the basis of the first captured image. For the reduction of the error caused by the subject's hand slight movement, the position adjustment was performed with the landmark, which was found with skeltonizing and extracting the diverging point. The pixel number of the blood vessel portion was counted and the thickness of the blood vessel was analyzed by performing a Fourier analysis. The Fourier analysis shows the peak at the frequency of 1.4 Hz corresponding to 84 beat count in a minute. For the evaluation of the proposed method, blood beat was measured with a sphygmomanometer simultaneously. As the results, the almost same pulse rate could be obtained from both method. These results indicate that the method has the possibility to count a pulse.

  11. Retinal blood flow measurement by using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Makita, Shuichi; Fabritius, Tapio; Miura, Masahiro; Yatagai, Toyohiko; Yasuno, Yoshiaki

    2008-02-01

    Quantification of the three-dimensional (3D) retinal vessel structure and blood flow is demonstrated. 3D blood flow distribution is obtained by Doppler optical coherence angiography (D-OCA). Vessel parameters, i.e. diameter, orientation, and position, are determined in an en face vessel image. The Doppler angle is estimated as the angle between the retinal vessel and the incident probing beam in representative cross-sectional flow image which extracted from the 3D flow distribution according to the vessel parameters. Blood flow velocity and volume rate can be quantified with these vessel parameters. The retinal blood flow velocity and volume rate are measured in the retinal vessels around the optic nerve head.

  12. BREATH MEASUREMENT AND MODELS TO ASSESS VOC DERMAL ABSORPTION IN WATER

    EPA Science Inventory

    Dermal exposure to volatile organic compounds (VOCs) in water results from environmental contamination of surface, ground-, and drinking waters. This exposure occurs both in occupational and residential settings. Compartmental models incorporating body burden measurements have ...

  13. Nursing student caring behaviors during blood pressure measurement.

    PubMed

    Becker, Mary Kay; Blazovich, Linda; Schug, Vicki; Schulenberg, Cathy; Daniels, Jessie; Neal, Diana; Pearson, Gloria; Preston, Sara; Ridgeway, Sharon; Simones, Joyce; Swiggum, Paula; Wenkel, Linda; Smith, MaryJo O

    2008-03-01

    The purpose of this multisite, nonexperimental study was to examine, using a repeated measures design, the effects of a teaching intervention designed to promote caring behaviors as students learn the psychomotor skill of blood pressure measurement. Watson's theory of human caring and a combination of cognitive and connectionist learning theories were used as the organizing construct. Baccalaureate nursing student participants were videotaped and evaluated at two points in time while performing the psychomotor skill of blood pressure measurement on a role-player. Role-players rated the students' caring behaviors using the Role Player Survey of Caring Behaviors During Blood Pressure Measurement instrument. Between these data collection points, students learned about caring behaviors through analysis of a videotaped role-play and required readings. An evaluator randomly selected 10 student videotapes from each of the 6 baccalaureate nursing program study sites and noted the presence or absence of caring behaviors on the Caring Behaviors During Blood Pressure Measurement instrument. Pretest and posttest scores on both subjective and objective research instruments were compared using descriptive statistics and repeated measures analysis of variance (ANOVA). Students demonstrated a significant improvement in objective and subjective caring behaviors between the two performance examinations. The findings support further investigation of teaching interventions to promote the development of caring behaviors during nursing psychomotor skill development. PMID:18380262

  14. Non-invasive measurement of blood oxygen levels.

    PubMed

    Beyerl, D

    1982-05-01

    Comparison of transcutaneous (TC) monitoring of blood oxygen levels to arterial blood gas analyses was made on patients at rest with room air, during exercise, and at rest with oxygen. Three different transcutaneous monitors were evaluated: Novametrix TC O2 Mette, Biochem Sensomat, and Radiometer TC M1. The Hewlett-Packard ear oximeter for measuring oxygen saturation was also compared to oxygen saturation values calculated on the Severinghaus slide rule. Using at least one measured PO2 as a baseline, either TC monitoring or ear oximetry were valuable tools in monitoring pulmonary function. PMID:7102718

  15. 21 CFR 862.3050 - Breath-alcohol test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breath-alcohol test system. 862.3050 Section 862....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened to measure alcohol in the human breath. Measurements obtained by this device are used in...

  16. 21 CFR 862.3050 - Breath-alcohol test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Breath-alcohol test system. 862.3050 Section 862....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened to measure alcohol in the human breath. Measurements obtained by this device are used in...

  17. 21 CFR 862.3050 - Breath-alcohol test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Breath-alcohol test system. 862.3050 Section 862....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened to measure alcohol in the human breath. Measurements obtained by this device are used in...

  18. 21 CFR 862.3050 - Breath-alcohol test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Breath-alcohol test system. 862.3050 Section 862....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened to measure alcohol in the human breath. Measurements obtained by this device are used in...

  19. 21 CFR 862.3050 - Breath-alcohol test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Breath-alcohol test system. 862.3050 Section 862....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened to measure alcohol in the human breath. Measurements obtained by this device are used in...

  20. Outdoor, indoor, and human breath content measurements of ammonia by tunable diode laser spectroscopy technique

    SciTech Connect

    Moskalenko, C.L.; Nadezhdinskii, A.I.

    1996-12-31

    Trace contents of ammonia in outdoor, indoor and exhaled air were measured on the base of high resolution absorption spectra. Tunable Diode Laser (TDL) system developed for this purpose possesses: {approximately}one second time constant, {approximately}200 cm{sup 3} sample volume, 5 ppb-sensitivity. The calibration of unit was based on measurements of relative intensities of sQ(3,1){hor_ellipsis}sQ(3,3) absorption lines of {nu}{sub 2S} and following calculation on the base of a priori data on strength and broadening coefficients of detected lines. Measured indoor contents (20--50 ppb) of ammonia was in 5--10 times higher than outdoor contents ({approximately}5 ppb). Approximately two times drop in NH{sub 3} room content after 6 p.m. was detected. Obtained behavior of ammonia content in respiration right after the smoking demonstrates that the removing of ammonia from lungs has the ventilation character. Measured contents of NH{sub 3} in human respiration was ranged between 120 and 220 ppb. The absence of ammonia content differences from respiration of smoking and non-smoking persons demonstrates that the accumulation of NH{sub 3} by humans seems to be rather negligible for a short time exposure, e.g., like smoking.

  1. Outdoor, indoor, and human breath content measurements of ammonia by tunable diode laser spectroscopy technique

    NASA Astrophysics Data System (ADS)

    Moskalenko, Konstantin L.; Nadezhdinskii, Alexander I.

    1996-10-01

    Trace contents of ammonia in outdoor, indoor and exhaled air were measured on the base of high resolution absorption spectra. Tunable diode laser system developed for this purpose possesses approximately one second time constant, approximately 200 cm3 sample volume, 5 ppb sensitivity. The calibration of unit was based on measurements of relative intensities of sQ(3,1)...sQ(3,3) absorption lines of v2s and following calculation on the base of a priori data on strength and broadening coefficients of detected lines. Measured indoor contents of ammonia was in 5-10 times higher than outdoor contents. Approximately two times drop in NH3 room content after 6 p.m. was detected. Obtained behavior of ammonia content in respiration right after the smoking demonstrates that the removing of ammonia from lungs has the ventilation character. Measured contents of NH3 in human respiration was ranged between 120 and 220 ppb. The absence of ammonia content differences from respiration of smoking and non smoking persons demonstrates that the accumulation of NH3 by human organism seems to be rather negligible for a short time exposure, e.g. like smoking.

  2. EXHALED BREATH ANALYSIS FOR HUMAN EXPOSURE RESEARCH

    EPA Science Inventory

    Exhaled breath collection and analysis has historically been used in environmental research studies to characterize exposures to volatile organic compounds. The use of this approach is based on the fact that many compounds present in blood are reflected in the breath, and that...

  3. Effects of breathing patterns and light exercise on linear and nonlinear heart rate variability.

    PubMed

    Weippert, Matthias; Behrens, Kristin; Rieger, Annika; Kumar, Mohit; Behrens, Martin

    2015-08-01

    Despite their use in cardiac risk stratification, the physiological meaning of nonlinear heart rate variability (HRV) measures is not well understood. The aim of this study was to elucidate effects of breathing frequency, tidal volume, and light exercise on nonlinear HRV and to determine associations with traditional HRV indices. R-R intervals, blood pressure, minute ventilation, breathing frequency, and respiratory gas concentrations were measured in 24 healthy male volunteers during 7 conditions: voluntary breathing at rest, and metronome guided breathing (0.1, 0.2 and 0.4 Hz) during rest, and cycling, respectively. The effect of physical load was significant for heart rate (HR; p < 0.001) and traditional HRV indices SDNN, RMSSD, lnLFP, and lnHFP (p < 0.01 for all). It approached significance for sample entropy (SampEn) and correlation dimension (D2) (p < 0.1 for both), while HRV detrended fluctuation analysis (DFA) measures DFAα1 and DFAα2 were not affected by load condition. Breathing did not affect HR but affected all traditional HRV measures. D2 was not affected by breathing; DFAα1 was moderately affected by breathing; and DFAα2, approximate entropy (ApEn), and SampEn were strongly affected by breathing. DFAα1 was strongly increased, whereas DFAα2, ApEn, and SampEn were decreased by slow breathing. No interaction effect of load and breathing pattern was evident. Correlations to traditional HRV indices were modest (r from -0.14 to -0.67, p < 0.05 to <0.01). In conclusion, while light exercise does not significantly affect short-time HRV nonlinear indices, respiratory activity has to be considered as a potential contributor at rest and during light dynamic exercise. PMID:26187271

  4. Pharmacological modulation of gastric emptying rate of solids as measured by the carbon labelled octanoic acid breath test: influence of erythromycin and propantheline.

    PubMed Central

    Maes, B D; Hiele, M I; Geypens, B J; Rutgeerts, P J; Ghoos, Y F; Vantrappen, G

    1994-01-01

    The *C (13C or 14C) labelled octanoic acid breath test was recently developed to measure the gastric emptying rate of solids. This study aimed to investigate whether it is sensitive enough to detect pharmacologically induced changes in the gastric emptying rate. Nine healthy volunteers were studied in basal condition, after intravenous administration of 200 mg erythromycin, and after peroral administration of 30 mg propantheline. Erythromycin significantly enhanced gastric emptying in all subjects, with an increase of the gastric emptying coefficient (p = 0.0043) in eight of nine and a fall in both the gastric half emptying time (p = 0.0020) and the lag phase (p = 0.0044) in all nine. Propantheline significantly reduced the gastric emptying rate, with a decreased gastric emptying coefficient (p = 0.0007) and an increased gastric half emptying time (p = 0.0168) in all subjects, but no change in the lag phase (p = 0.1214). Further mathematical analysis showed that breath sampling at 15 minutes intervals over a four hour period is recommended to guarantee accuracy and the discriminative value of the breath test in various gastric emptying patterns. In conclusion the *C labelled octanoic acid breath test is sufficiently sensitive to show pharmacologically induced changes of gastric emptying rates of solids. PMID:8150342

  5. Viscoelastic properties of blood studied through piezoresistance measurements.

    PubMed

    Peng, Yiyan; Turng, Lih-Sheng; Cui, Zhixiang; Woodson, Robert D; Li, Haimei; Wang, Xiaofeng

    2011-01-01

    Piezoresistance describes the change of electrical resistance in a material undergoing deformation. Heterogeneous materials having different resistivities of dispersed and continuous matrix phases, such as blood (comprised of red and white blood cells and platelets suspended in plasma), can exhibit the piezoresistance effect. For an initially isotropic material, two independent intrinsic material coefficients, λ1 and λ2, would uniquely describe the piezoresistance phenomenon. Materials undergoing deformation affect a material's resistivity in two ways: (a) by introducing anisotropy in the material, which is characterized by λ1 and (b) by changing the volume density of the inclusions, which is associated with (1/3 λ1+λ2). In this paper, the piezoresistance effect in bovine blood samples is studied under oscillatory shear flow with a planar sensor rosette. The first piezoresistance coefficient, λ1, was measured at various frequencies and shear rates in the blood flow and compared with cos δ (equal to G'/G*, where G' and G* are the storage and complex moduli, respectively), which reflects the degree of elasticity. The coefficient λ1 was found to have a trend similar to that of cos δ under all conditions tested. Thus λ1 might potentially be used to characterize the viscoelastic properties of blood and the deformability of red blood cells, thus clarifying pathophysiology and facilitating diagnosis. PMID:22156031

  6. Automated blood pressure measurement (ABPM) in the elderly.

    PubMed

    Trenkwalder, P

    1996-01-01

    Application and feasibility of automated ambulatory blood pressure measurement (ABPM) in the elderly are comparable to younger age groups. Major side-effects are sleep disturbances and pain during cuff-inflation. The main indications for ABPM are diagnosis and control of treatment in hypertensive patients. Further indications are the diagnosis of syncope or hypotensive disorders and the diagnostic work-up of symptoms like vertigo, dizziness and dyspnea. In hypertensives, ABPM can easily assess the "white coat" effect and cases of "white coat" hypertension (prevalence in the elderly 15-25%). The prognostic implications of "white coat" hypertensions remain to be determined. Recording of the total 24-h blood pressure profile with analysis of circadian blood pressure changes, the day-night difference and the early morning surge raises the possibility to assess age-specific patterns. The drop in blood pressure at night (during sleep) is usually decreased and less frequently observed in elderly hypertensives. Possible explanations include decreased daytime activity, an altered sleep pattern in the elderly and secondary forms of hypertension. So-called "non-dippers", with no adequate drop in night-time blood pressure, show a significant increase in cardiovascular complications. Control of treatment via ABPM can assess non-responders and cases of overtreatment, and permits a fairly objective analysis of side-effects. Episodes of transient myocardial ischemia and possible trigger mechanisms can be assessed by simultaneous application of ABPM and Holter monitoring. The insufficient control of hypertension in the majority of elderly patients and the current lower target blood pressures in the elderly call for new methods to improve the level and quality of antihypertensive treatment. Although ABPM provides a closer correlation to target organ damage than measurement of office (casual) blood pressure, and ABPM frequently improves or at least facilitates the care of elderly

  7. Knowledge of accurate blood pressure measurement procedures in chiropractic students

    PubMed Central

    Crosley, Angela M.; Rose, James R. La

    2013-01-01

    Objective Blood pressure measurement is a basic clinical procedure. However, studies have shown that many errors are made when health care providers acquire blood pressure readings. Our study assessed knowledge of blood pressure measurement procedures in chiropractic students. Methods This was an observational, descriptive study. A questionnaire based on one created by the American Heart Association was given to 1st, 2nd, 3rd, and final year students (n = 186). A one way ANOVA was used to analyze the data. Results Of the students 80% were confident that their knowledge of this clinical skill was adequate or better. However, the overall score on the knowledge test of blood pressure–taking skills was 52% (range, 24%–88%). The only significant difference in the mean scores was between the 1st and 2nd year students compared to the 3rd and 4th year students (p < .005). Of the 16 questions given, the following mean scores were: 1st year 10.45, 2nd year 9.75, 3rd year 7.93, and 4th year 8.33. Of the 16 areas tested, 10 were of major concern (test item score <70%), showing the need for frequent retraining of chiropractic students. Conclusion Consistent with studies in other health care disciplines, our research found the knowledge of blood pressure skills to be deficient in our sample. There is a need for subsequent training in our teaching program. PMID:23957320

  8. 21 CFR 870.1130 - Noninvasive blood pressure measurement system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Noninvasive blood pressure measurement system. 870.1130 Section 870.1130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... three pressures can be derived through the use of tranducers placed on the surface of the body....

  9. 21 CFR 870.1130 - Noninvasive blood pressure measurement system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Noninvasive blood pressure measurement system. 870.1130 Section 870.1130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... three pressures can be derived through the use of tranducers placed on the surface of the body....

  10. 21 CFR 870.1130 - Noninvasive blood pressure measurement system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Noninvasive blood pressure measurement system. 870.1130 Section 870.1130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... three pressures can be derived through the use of tranducers placed on the surface of the body....

  11. 21 CFR 870.1130 - Noninvasive blood pressure measurement system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Noninvasive blood pressure measurement system. 870.1130 Section 870.1130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... three pressures can be derived through the use of tranducers placed on the surface of the body....

  12. Host and environmental predictors of exhaled breath temperature in the elderly

    PubMed Central

    2013-01-01

    Background Exhaled breath temperature has been suggested as a new method to detect and monitor pathological processes in the respiratory system. The putative mechanism of this approach is based upon changes in the blood flow. So far potential factors that influence breath temperature have not been studied in the general population. Methods The exhaled breath temperature was measured in 151 healthy non-smoking elderly (aged: 60–80 years) at room temperature with the X-halo device with an accuracy of 0.03°C. We related exhaled breath temperature by use of regression models with potential predictors including: host factors (sex, age) and environmental factors (BMI, physical activity, and traffic indicators). Results Exhaled breath temperature was lower in women than in men and was inversely associated with age, physical activity. BMI and daily average ambient temperature were positively associated with exhaled breath temperature. Independent of the aforementioned covariates, exhaled breath temperature was significantly associated with several traffic indicators. Residential proximity to major road was inversely associated with exhaled breath temperature: doubling the distance to the nearest major intense road was observed a decrease of 0.17°C (95% CI: -0.33 to -0.01; p = 0.036). Conclusions Exhaled breath temperature has been suggested as a noninvasive method for the evaluation of airway inflammation. We provide evidence that several factors known to be involved in proinflammatory conditions including BMI, physical activity and residential proximity to traffic affect exhaled breath temperature. In addition, we identified potential confounders that should be taken into account in clinical and epidemiological studies on exhaled breath temperature including sex, age, and ambient temperature. PMID:24365236

  13. Arterial compliance probe for local blood pulse wave velocity measurement.

    PubMed

    Nabeel, P M; Joseph, Jayaraj; Sivaprakasam, Mohanasankar

    2015-08-01

    Arterial compliance and vessel wall dynamics are significant in vascular diagnosis. We present the design of arterial compliance probes for measurement of local pulse wave velocity (PWV). Two designs of compliance probe are discussed, viz (a) a magnetic plethysmograph (MPG) based probe, and (b) a photoplethysmograph (PPG) based probe. The ability of the local PWV probes to consistently capture carotid blood pulse waves is verified by in-vivo trials on few volunteers. The probes could reliably perform repeatable measurements of local PWV from carotid artery along small artery sections less than 20 mm. Further, correlation between the measured values of local PWV using probes and various measures of blood pressure (BP) was also investigated. The study indicates that such arterial compliance probes have strong potential in cuff less BP monitoring. PMID:26737589

  14. Software Tool for Analysis of Breathing-Related Errors in Transthoracic Electrical Bioimpedance Spectroscopy Measurements

    NASA Astrophysics Data System (ADS)

    Abtahi, F.; Gyllensten, I. C.; Lindecrantz, K.; Seoane, F.

    2012-12-01

    During the last decades, Electrical Bioimpedance Spectroscopy (EBIS) has been applied in a range of different applications and mainly using the frequency sweep-technique. Traditionally the tissue under study is considered to be timeinvariant and dynamic changes of tissue activity are ignored and instead treated as a noise source. This assumption has not been adequately tested and could have a negative impact and limit the accuracy for impedance monitoring systems. In order to successfully use frequency-sweeping EBIS for monitoring time-variant systems, it is paramount to study the effect of frequency-sweep delay on Cole Model-based analysis. In this work, we present a software tool that can be used to simulate the influence of respiration activity in frequency-sweep EBIS measurements of the human thorax and analyse the effects of the different error sources. Preliminary results indicate that the deviation on the EBIS measurement might be significant at any frequency, and especially in the impedance plane. Therefore the impact on Cole-model analysis might be different depending on method applied for Cole parameter estimation.

  15. How Cities Breathe: Ground-Referenced, Airborne Hyperspectral Imaging Precursor Measurements To Space-Based Monitoring

    NASA Technical Reports Server (NTRS)

    Leifer, Ira; Tratt, David; Quattrochi, Dale; Bovensmann, Heinrich; Gerilowski, Konstantin; Buchwitz, Michael; Burrows, John

    2013-01-01

    the complex and often aerosol laden, humid, urban microclimates, atmospheric transport and profile monitoring, spatial resolution, temporal cycles (diurnal and seasonal which involve interactions with the surrounding environment diurnal and seasonal cycles) and representative measurement approaches given traffic realities. Promising approaches incorporate contemporaneous airborne remote sensing and in situ measurements, nocturnal surface surveys, with ground station measurement

  16. NEW METHODOLOGY FOR IDENTIFYING POTENTIAL HUMAN BIOMARKERS BY COLLECTION AND CONCENTRATION OF EXHALED BREATH CONDENSATE

    EPA Science Inventory

    In many studies of human exposure, the measurement of pollutant chemicals in the environment (air, water, food, soil, etc.) is being supplemented by their additional measurement in biological media such as human breath, blood, and urine. This allows an unambiguous confirmation...

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

    PubMed

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

    2016-01-01

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

  18. Blood

    MedlinePlus

    ... solid part of your blood contains red blood cells, white blood cells, and platelets. Red blood cells (RBC) deliver oxygen from your lungs to your tissues and organs. White blood cells (WBC) fight infection and are part of your ...

  19. Intravital video microscopy measurements of retinal blood flow in mice.

    PubMed

    Harris, Norman R; Watts, Megan N; Leskova, Wendy

    2013-01-01

    Alterations in retinal blood flow can contribute to, or be a consequence of, ocular disease and visual dysfunction. Therefore, quantitation of altered perfusion can aid research into the mechanisms of retinal pathologies. Intravital video microscopy of fluorescent tracers can be used to measure vascular diameters and bloodstream velocities of the retinal vasculature, specifically the arterioles branching from the central retinal artery and of the venules leading into the central retinal vein. Blood flow rates can be calculated from the diameters and velocities, with the summation of arteriolar flow, and separately venular flow, providing values of total retinal blood flow. This paper and associated video describe the methods for applying this technique to mice, which includes 1) the preparation of the eye for intravital microscopy of the anesthetized animal, 2) the intravenous infusion of fluorescent microspheres to measure bloodstream velocity, 3) the intravenous infusion of a high molecular weight fluorescent dextran, to aid the microscopic visualization of the retinal microvasculature, 4) the use of a digital microscope camera to obtain videos of the perfused retina, and 5) the use of image processing software to analyze the video. The same techniques can be used for measuring retinal blood flow rates in rats. PMID:24429840

  20. Simplified, noninvasive PET measurement of blood-brain barrier permeability

    SciTech Connect

    Iannotti, F.; Fieschi, C.; Alfano, B.; Picozzi, P.; Mansi, L.; Pozzilli, C.; Punzo, A.; Del Vecchio, G.; Lenzi, G.L.; Salvatore, M.

    1987-05-01

    Blood-brain barrier (BBB) permeability to (/sup 68/Ga)EDTA was measured by positron emission tomography (PET) in four normal volunteers and in 11 patients with brain tumors. A unidirectional transfer constant, Ki, was calculated applying multiple-time graphical analysis (MTGA). This method allows the detection of backflux from brain to blood and, by generalization, the measurement of the constant Kb (brain to blood). Furthermore, the need for an independent measurement of the intravascular tracer is obviated: MTGA itself provides an estimate of the cerebral plasma volume (Vp). In the four normal volunteers the Ki was 3.0 +/- 0.8 X 10(-4) ml g-1 min-1 (mean +/- SD) and the Vp 0.034 +/- 0.007 ml g-1. A net increase in Ki up to a maximum of 121.0 X 10(-4) ml g-1 min-1 (correspondent value of Kb = 0.025 min-1) as well as an increase of Vp was observed in malignant tumors. The input function was calculated using both the (/sup 68/Ga)EDTA concentration in sequential arterial blood samples and, noninvasively, the activity derived from the superior sagittal sinus image. The values of Ki and Vp from these two calculations were in good agreement. The application of MTGA to PET permits the evaluation of passage of substances across the BBB without making assumptions about the compartments in which the tracer distributes.

  1. Oronasal breathing during exercise.

    PubMed

    Saibene, F; Mognoni, P; Lafortuna, C L; Mostardi, R

    1978-12-15

    The shift from nasal to oronasal breathing (ONBS) has been observed on 73 subjects with two independent methods. A first group of 63 subjects exercising on a bicycle ergometer at increasing work load (98--196 W) has been observed. On 35 subjects the highest value of ventilation attained with nasal breathing was 40.2 +/- 9.41 . min-1 S.D. Ten subjects breathed through the mouth at all loads, while 5 never opened the mouth. On 13 subjects it was not possible to make reliable measurements. On a second group of 10 subjects utilizing a different techniques which did not need a face mask, the ventilation at which one changes the pattern of breathing was found to be 44.2 +/- 13.51 . min-1 S.D. On the same subjects nasal resistance did not show any correlation with ONBS. It is concluded that ONBS is not solely determined by nasal resistance, though an indirect effect due to hypoventilation and hence to changes in alveolar air composition cannot be ruled out. It is likely that ONBS is also influenced by psychological factors. PMID:569826

  2. Optimal Blood Suppression Inversion Time Based on Breathing Rates and Heart Rates to Improve Renal Artery Visibility in Spatial Labeling with Multiple Inversion Pulses: A Preliminary Study

    PubMed Central

    Pei, Yigang; Li, Fang; Shen, Hao; Long, Xueying; Liu, Hui; Wang, Xiaoyi; Liu, Jinkang

    2016-01-01

    Objective To determine whether an optimal blood suppression inversion time (BSP TI) can boost arterial visibility and whether the optimal BSP TI is related to breathing rate (BR) and heart rate (HR) for hypertension subjects in spatial labeling with multiple inversion pulses (SLEEK). Materials and Methods This prospective study included 10 volunteers and 93 consecutive hypertension patients who had undergone SLEEK at 1.5T MRI system. Firstly, suitable BSP TIs for displaying clearly renal artery were determined in 10 volunteers. Secondly, non-contrast enhanced magnetic resonance angiography with the suitable BSP TIs were performed on those hypertension patients. Then, renal artery was evaluated and an optimal BSP TI to increase arterial visibility was determined for each patient. Patients' BRs and HRs were recorded and their relationships with the optimal BSP TI were analyzed. Results The optimal BSP TI was negatively correlated with BR (r1 = -0.536, P1 < 0.001; and r2 = -0.535, P2 < 0.001) and HR (r1 = -0.432, P1 = 0.001; and r2 = -0.419, P2 = 0.001) for 2 readers (κ = 0.93). For improving renal arterial visibility, BSP TI = 800 ms could be applied as the optimal BSP TI when the 95% confidence interval were 17-19/min (BR1) and 74-82 bpm (HR1) for reader#1 and 17-19/min (BR2) and 74-83 bpm (HR2) for reader#2; BSP TI = 1100 ms while 14-15/min (BR1, 2) and 71-76 bpm (HR1, 2) for both readers; and BSP TI = 1400 ms when 13-16/min (BR1) and 63-68 bpm (HR1) for reader#1 and 14-15/min (BR2) and 64-70 bpm (HR2) for reader#2. Conclusion In SLEEK, BSP TI is affected by patients' BRs and HRs. Adopting the optimal BSP TI based on BR and HR can improve the renal arterial visibility and consequently the working efficiency. PMID:26798218

  3. Absolute blood velocity measured with a modified fundus camera

    NASA Astrophysics Data System (ADS)

    Duncan, Donald D.; Lemaillet, Paul; Ibrahim, Mohamed; Nguyen, Quan Dong; Hiller, Matthias; Ramella-Roman, Jessica

    2010-09-01

    We present a new method for the quantitative estimation of blood flow velocity, based on the use of the Radon transform. The specific application is for measurement of blood flow velocity in the retina. Our modified fundus camera uses illumination from a green LED and captures imagery with a high-speed CCD camera. The basic theory is presented, and typical results are shown for an in vitro flow model using blood in a capillary tube. Subsequently, representative results are shown for representative fundus imagery. This approach provides absolute velocity and flow direction along the vessel centerline or any lateral displacement therefrom. We also provide an error analysis allowing estimation of confidence intervals for the estimated velocity.

  4. Measurement of normal portal venous blood flow by Doppler ultrasound.

    PubMed

    Brown, H S; Halliwell, M; Qamar, M; Read, A E; Evans, J M; Wells, P N

    1989-04-01

    The volume flow rate of blood in the portal vein was measured using a duplex ultrasound system. The many errors inherent in the duplex method were assessed with particular reference to the portal vein and appropriate correction factors were obtained by in vitro calibration. The effect of posture on flow was investigated by examining 45 healthy volunteers in three different positions; standing, supine and tilted head down at 20 degrees from the horizontal. The mean volume blood flow in the supine position was 864 (188)ml/min (mean 1SD). When standing, the mean volume blood flow was significantly reduced by 26% to 662 (169)ml/min. There was, however, no significant difference between flow when supine and when tilted head down at 20 degrees from the horizontal. PMID:2653973

  5. Real-time analysis of breath for carbon tetrachloride and its metabolites

    SciTech Connect

    Kenny, D.V.; Callahan, P.J.; Thrall, K.D.

    1995-12-31

    Real-time breath analysis offers a non-invasive method to detect exposure to toxic air pollutants. Breath measurements are useful in environmental exposure studies, and may provide evidence about previous long-term or repeated exposures in environments that are not easy to monitor. If breath samples are collected during or immediately following a short term exposure, breath measurements can be used to predict the peak exposure. Previous breath sampling methodologies have been to collect repeated 1-minute breath samples at 5 minute intervals. Although this method can aid in describing the rapid exponential emptying of the blood compartment that occurs following peak exposure, sampling 5 minute intervals still forces an approximation of the true shape of the clearance kinetics. The authors have developed a methodology to quantitively measure the concentration of exhaled volatile compounds in real-time using laboratory rats. Continuously monitoring breath for a parent toxicant and its metabolite(s) provides input into physiologically based pharmacokinetic (PBPK) models to describe the bio-kinetics of a chemical in the body. Real-time analyses are better than batch sampling methods because of the rapidly changing kinetics of elimination of some volatile chemicals from the body.

  6. Measuring blood glucose in neonatal units: how does hemocue compare?

    PubMed Central

    Deshpande, S A; Matthews, J N; Platt, M P

    1996-01-01

    Rapid and reliable determination of blood glucose concentration is essential during the neonatal period to prevent adverse neurodevelopmental outcome from hypoglycaemia. Despite their unreliability, reagent strip methods continue to be used extensively in neonatal nurseries due to their rapidity and convenience. Recently, a new portable laboratory standard technique has been introduced (HemoCue B-Glucose system) for whole blood glucose determination. It is particularly suitable for near-patient testing in neonatal units. This new method, as well as other established methods of whole blood (Yellow Springs Instrument (YSI) and a hexokinase method on Cobas Bio), and plasma (Kodak Ektachem) glucose measurement, were therefore evaluated for their accuracy and concordance of measurements taken in the neonatal period. There were substantial discrepancies among the four methods of glucose measurement with wide limits of agreement between these methods. The glucose concentrations measured by HemoCue and YSI (n = 206), HemoCue and hexokinase (n = 113), HemoCue and plasma glucose on Ektachem (n = 69) and hexokinase and Ektachem (n = 66) were likely to differ by -29 to +61%, -23 to +56%, -36 to +65%, and -19 to +30%, respectively. Even the laboratory methods of blood glucose determination, therefore, can not be used interchangeably. Using a model based approach, the probabilities of "discordant" classification as hypo- or normo-glycaemia were estimated to be 6.8%, 6.5%, and 7.1% between HemoCue and YSI, HemoCue and hexokinase on Cobas Bio, and HemoCue and Ektachem analysers, respectively. In view of these low probabilities of discordant classification with other glucose analysers, the HemoCue system may offer a reasonable compromise between bedside and laboratory blood glucose estimations in neonates. PMID:8976688

  7. Shortness of Breath

    MedlinePlus

    ... Body & lifestyle changes > Shortness of breath Shortness of breath E-mail to a friend Please fill in ... oxygen your baby gets. Causes of shortness of breath during pregnancy Early pregnancy In the first few ...

  8. Breath alcohol test

    MedlinePlus

    Alcohol test - breath ... There are various brands of breath alcohol tests. Each one uses a different method to test the level of alcohol in the breath. The machine may be electronic or manual. One ...

  9. Breath-Holding Spells

    MedlinePlus

    ... less than a minute before a child regains consciousness and resumes breathing normally. Breath-holding spells can ... spells cause kids to stop breathing and lose consciousness for up to a minute. In the most ...

  10. Blood biomarkers for brain injury: What are we measuring?

    PubMed Central

    Kawata, Keisuke; Liu, Charles Y.; Merkel, Steven F.; Ramirez, Servio H.; Tierney, Ryan T.; Langford, Dianne

    2016-01-01

    Accurate diagnosis for mild traumatic brain injury (mTBI) remains challenging, as prognosis and return-to-play/work decisions are based largely on patient reports. Numerous investigations have identified and characterized cellular factors in the blood as potential biomarkers for TBI, in the hope that these factors may be used to gauge the severity of brain injury. None of these potential biomarkers have advanced to use in the clinical setting. Some of the most extensively studied blood biomarkers for TBI include S100β, neuron-specific enolase, glial fibrillary acidic protein, and Tau. Understanding the biological function of each of these factors may be imperative to achieve progress in the field. We address the basic question: what are we measuring? This review will discuss blood biomarkers in terms of cellular origin, normal and pathological function, and possible reasons for increased blood levels. Considerations in the selection, evaluation, and validation of potential biomarkers will also be addressed, along with mechanisms that allow brain-derived proteins to enter the bloodstream after TBI. Lastly, we will highlight perspectives and implications for repetitive neurotrauma in the field of blood biomarkers for brain injury. PMID:27181909