scholarly journals Tidal volume single-breath washin of SF6 and CH4 in transient microgravity

2003 ◽  
Vol 94 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Brigitte Dutrieue ◽  
Manuel Paiva ◽  
Sylvia Verbanck ◽  
Marine Le Gouic ◽  
Chantal Darquenne ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Conformational Changes ◽  
Functional Residual Capacity ◽  
Vital Capacity ◽  
Time Dependent ◽  
Phase Iii ◽  
Lung Volumes ◽  
Single Breath ◽  
Residual Capacity ◽  
Slope Difference

We performed tidal volume single-breath washins (SBW) by using tracers of different diffusivity and varied the time spent in microgravity (μG) before the start of the tests to look for time-dependent effects. SF6 and CH4 phase III slopes decreased by 35 and 26%, respectively, in μG compared with 1 G ( P < 0.05), and the slope difference between gases disappeared. There was no effect of time in μG, suggesting that neither the hypergravity period preceding μG nor the time spent in μG affected gas mixing at volumes near functional residual capacity. In previous studies using SF6 and He (Lauzon A-M, Prisk GK, Elliott AR, Verbanck S, Paiva M, and West JB. J Appl Physiol 82: 859–865, 1997), the vital capacity SBW showed an increase in slope difference between gases in transient μG, the opposite of the decrease in sustained μG. In contrast, tidal volume SBW showed a decrease in slope difference in both μG conditions. Because it is only the behavior of the more diffusive gas that differed between maneuvers and μG conditions, we speculate that, in the previous vital capacity SBW, the hypergravity period preceding the test in transient μG provoked conformational changes at low lung volumes near the acinar entrance.

Helium and sulfur hexafluoride bolus washin in short-term microgravity

1999 ◽  
Vol 86 (5) ◽  
pp. 1594-1602 ◽  
Author(s):  
Brigitte Dutrieue ◽  
Anne-Marie Lauzon ◽  
Sylvia Verbanck ◽  
Ann R. Elliott ◽  
John B. West ◽  
...  
Keyword(s):  
Sulfur Hexafluoride ◽  
Vital Capacity ◽  
Parabolic Flight ◽  
Phase Iii ◽  
Lung Volumes ◽  
Single Breath ◽  
Close Proximity ◽  
Slope Difference ◽  
The Difference ◽  
Phase Iii Slope

We performed single-breath washout (SBW) tests in which He and sulfur hexafluoride (SF6) were inspired throughout the vital capacity inspirations or were inhaled as discrete boluses at different points in the inspiration. Tests were performed in normal gravity (1 G) and in up to 27 s of microgravity (μG) during parabolic flight. The phase III slope of the SBW could be accurately reconstructed from individual bolus tests when allowance for airways closure was made. Bolus tests showed that most of the SBW phase III slope results from events during inspiration at lung volumes below closing capacity and near total lung capacity, as does the SF6-He phase III slope difference. Similarly, the difference between 1 G and μG in phase III slopes for both gases was entirely accounted for by gravity-dependent events at high and low lung volumes. Phase IV height was always larger for SF6 than for He, suggesting at least some airway closure in close proximity to airways that remain open at residual volume. These results help explain previous studies in μG, which show large changes in gas mixing in vital capacity maneuvers but only small effects in tidal volume breaths.

Effect of posture on static lung volumes and pulmonary mechanics in pneumonectomized rabbits

1993 ◽  
Vol 74 (1) ◽  
pp. 415-422 ◽  
Author(s):  
L. E. Olson
Keyword(s):  
Functional Residual Capacity ◽  
Left Lung ◽  
Lateral Position ◽  
Phase Iii ◽  
Pulmonary Mechanics ◽  
Lung Volumes ◽  
Left Lateral Position ◽  
Single Breath ◽  
Residual Capacity ◽  
Induced Changes

Static lung volumes, lung (CL) and respiratory system compliance (Crs), and the slope of phase III of the single-breath O2 test (slope III) were measured in rabbits in the prone, supine, and right and left lateral positions. Control rabbits, rabbits that had the left lung removed (Px), and rabbits that had the left lung removed and replaced with wax (Px + W) were studied. Surgeries were performed > or = 7 wk before study. Lung volumes, Crs, and slope III were not different among groups. Total lung capacity, vital capacity, residual volume, Crs, and slope III were smallest in all rabbits in the prone position. Functional residual capacity and expiratory reserve volume were unaffected by posture in control rabbits but were larger in Px and Px + W rabbits in the left lateral position. CL was unaffected by posture but was smaller in Px and Px + W rabbits than in control rabbits. Pneumonectomy-induced changes in lung shape altered the effect of posture on functional residual capacity but not on regional lung function, as assessed by the single-breath O2 test.

STUDIES OF RESPIRATORY PHYSIOLOGY IN CHILDREN

PEDIATRICS ◽  
1959 ◽  
Vol 24 (2) ◽  
pp. 181-193
Author(s):  
C. D. Cook ◽  
P. J. Helliesen ◽  
L. Kulczycki ◽  
H. Barrie ◽  
L. Friedlander ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Lung Compliance ◽  
Respiratory Physiology ◽  
Residual Volume ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Residual Capacity

Tidal volume, respiratory rate and lung volumes have been measured in 64 patients with cystic fibrosis of the pancreas while lung compliance and resistance were measured in 42 of these. Serial studies of lung volumes were done in 43. Tidal volume was reduced and the respiratory rate increased only in the most severely ill patients. Excluding the three patients with lobectomies, residual volume and functional residual capacity were found to be significantly increased in 46 and 21%, respectively. These changes correlated well with the roentgenographic evaluation of emphysema. Vital capacity was significantly reduced in 34% while total lung capacity was, on the average, relatively unchanged. Seventy per cent of the 61 patients had a signficantly elevated RV/TLC ratio. Lung compliance was significantly reduced in only the most severely ill patients but resistance was significantly increased in 35% of the patients studied. The serial studies of lung volumes showed no consistent trends among the groups of patients in the period between studies. However, 10% of the surviving patients showed evidence of significant improvement while 15% deteriorated. [See Fig. 8. in Source Pdf.] Although there were individual discrepancies, there was a definite correlation between the clinical evaluation and tests of respiratory function, especially the changes in residual volume, the vital capacity, RV/ TLC ratio and the lung compliance and resistance.

Mode shift of an inhaled aerosol bolus is correlated with flow sequencing in the human lung

2002 ◽  
Vol 92 (3) ◽  
pp. 1232-1238 ◽  
Author(s):  
Christopher N. Mills ◽  
Chantal Darquenne ◽  
G. Kim Prisk
Keyword(s):  
Vital Capacity ◽  
Normal Subjects ◽  
Phase Iii ◽  
Mode Shift ◽  
Nitrogen Washout ◽  
Single Breath ◽  
Posture Change ◽  
Supine Posture ◽  
Residual Capacity ◽  
Phase Iii Slope

We studied the effects on aerosol bolus inhalations of small changes in convective inhomogeneity induced by posture change from upright to supine in nine normal subjects. Vital capacity single-breath nitrogen washout tests were used to determine ventilatory inhomogeneity change between postures. Relative to upright, supine phase III slope was increased 33 ± 11% (mean ± SE, P < 0.05) and phase IV height increased 25 ± 11% ( P < 0.05), consistent with an increase in convective inhomogeneity likely due to increases in flow sequencing. Subjects also performed 0.5-μm-particle bolus inhalations to penetration volumes (Vp) between 150 and 1,200 ml during a standardized inhalation from residual volume to 1 liter above upright functional residual capacity. Mode shift (MS) in supine posture was more mouthward than upright at all Vp, changing by 11.6 ml at Vp = 150 ml ( P < 0.05) and 38.4 ml at Vp = 1,200 ml ( P < 0.05). MS and phase III slope changes correlated positively at deeper Vp. Deposition did not change at any Vp, suggesting that deposition did not cause the MS change. We propose that the MS change results from increased sequencing in supine vs. upright posture.

Postural effects on lung volumes and asynchronous ventilation in anesthetized horses

1980 ◽  
Vol 48 (1) ◽  
pp. 97-103 ◽  
Author(s):  
P. R. Sorenson ◽  
N. E. Robinson
Keyword(s):  
Lung Volume ◽  
Phase Iii ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Single Breath ◽  
Supine Posture ◽  
Residual Capacity ◽  
Phase Iii Slope ◽  
Average Body ◽  
Prone Posture

Quasi-static pressure-volume curves and single-breath nitrogen washouts were performed simultaneously on eight anesthetized horses (average body wt = 485 kg) in left lateral, right lateral, prone, and supine postures (sequence randomized). The shift from prone to lateral or supine posture decreased expiratory reserve volume (ERV), vital capacity (VC), residual volume (RV), functional residual capacity (FRC), and total lung capacity (TLC); RV and FRC expressed as %TLC were unchanged, suggesting that in the lateral and supine postures a significant portion of the lung volume was not recruited by VC maneuvers. Phase III slope increased from 0.13 %N2/l in prone horses to 0.34 %N2/l in the lateral and supine positions. The onset of phase IV was not significantly different from FRC in the prone or laterally recombent animal, but exceeded FRC in the supine horse. The sequence of body positions had no effect on any of our results indicating that all changes in lung volumes and regional asynchronous ventilation c;n be reversed by placing the horse in the prone posture. The reduction in lung volume and increased asynchronous ventilation in the lateral and supine horse suggests that impaired gas exchange in anesthetized horses is predominantly related to posture, and not general anesthesia.

Volume-pressure relationships of the thorax and lung in the newborn

1959 ◽  
Vol 14 (6) ◽  
pp. 909-913 ◽  
Author(s):  
Emilio Agostoni
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Lung Capacity ◽  
Extended Range ◽  
Residual Capacity ◽  
Respiratory Apparatus ◽  
Retraction Force ◽  
Volume Range

The volume-pressure relationships of the respiratory apparatus have been studied in the dog fetus and in newborn and adult dogs. The mechanical changes produced when air first enters the lung have been described. In the newborn the lung-thorax compliance per unit vital capacity, taken over an extended range, is larger than in the adult: it is smaller, over the tidal volume range, during the first few days of life. The compliance of the thorax, particularly high at birth, decreases then progressively. The compliance of the lung after some days of life is similar to that of the adult. The relaxation volume and the functional residual capacity per total lung capacity increase significantly during growth. The lung retraction force, at relaxation volume, is smaller in the newborn than in the adult. Submitted on June 19, 1959

scholarly journals Effects of rapid saline infusion on lung mechanics and airway responsiveness in humans

2003 ◽  
Vol 95 (2) ◽  
pp. 728-734 ◽  
Author(s):  
Riccardo Pellegrino ◽  
Raffaele Dellacà ◽  
Peter T. Macklem ◽  
Andrea Aliverti ◽  
Stefania Bertini ◽  
...  
Keyword(s):  
Functional Residual Capacity ◽  
Forced Vital Capacity ◽  
Vital Capacity ◽  
Forced Expiratory Volume ◽  
Airway Responsiveness ◽  
Saline Infusion ◽  
Lung Mechanics ◽  
Elastic Recoil ◽  
Lung Volumes ◽  
Residual Capacity

Lung mechanics and airway responsiveness to methacholine (MCh) were studied in seven volunteers before and after a 20-min intravenous infusion of saline. Data were compared with those of a time point-matched control study. The following parameters were measured: 1-s forced expiratory volume, forced vital capacity, flows at 40% of control forced vital capacity on maximal (V̇m40) and partial (V̇p40) forced expiratory maneuvers, lung volumes, lung elastic recoil, lung resistance (Rl), dynamic elastance (Edyn), and within-breath resistance of respiratory system (Rrs). Rl and Edyn were measured during tidal breathing before and for 2 min after a deep inhalation and also at different lung volumes above and below functional residual capacity. Rrs was measured at functional residual capacity and at total lung capacity. Before MCh, saline infusion caused significant decrements of forced expiratory volume in 1 s, V̇m40, and V̇p40, but insignificantly affected lung volumes, elastic recoil, Rl, Edyn, and Rrs at any lung volume. Furthermore, saline infusion was associated with an increased response to MCh, which was not associated with significant changes in the ratio of V̇m40 to V̇p40. In conclusion, mild airflow obstruction and enhanced airway responsiveness were observed after saline, but this was not apparently due to altered elastic properties of the lung or inability of the airways to dilate with deep inhalation. It is speculated that it was likely the result of airway wall edema encroaching on the bronchial lumen.

scholarly journals Exercise-induced bronchodilation in natural and induced asthma: effects on ventilatory response and performance

2002 ◽  
Vol 92 (6) ◽  
pp. 2353-2360 ◽  
Author(s):  
Emanuele Crimi ◽  
Riccardo Pellegrino ◽  
Attilio Smeraldi ◽  
Vito Brusasco
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Lung Volume ◽  
Forced Vital Capacity ◽  
Vital Capacity ◽  
Breathing Frequency ◽  
Forced Expiratory Flow ◽  
Residual Capacity ◽  
Group 2 ◽  
Group 1

We studied whether bronchodilatation occurs with exercise during the late asthmatic reaction (LAR) to allergen ( group 1, n = 13) or natural asthma (NA; group 2, n = 8) and whether this is sufficient to preserve maximum ventilation (V˙e max), oxygen consumption (V˙o 2 max), and exercise performance (W˙max ). In group 1, partial forced expiratory flow at 30% of resting forced vital capacity increased during exercise, both at control and LAR. W˙max was slightly reduced at LAR, whereasV˙e max, tidal volume, breathing frequency, and V˙o 2 max were preserved. Functional residual capacity and end-inspiratory lung volume were significantly larger at LAR than at control. In group 2, partial forced expiratory flow at 30% of resting forced vital capacity increased greatly with exercise during NA but did not attain control values after appropriate therapy. Compared with control, W˙max was slightly less during NA, whereas V˙o 2 maxand V˙e max were similar. Functional residual capacity, but not end-inspiratory lung volume at maximum load, was significantly greater than at control, whereas tidal volume decreased and breathing frequency increased. In conclusion, remarkable exercise bronchodilation occurs during either LAR or NA and allowsV˙e max andV˙o 2 max to be preserved with small changes in breathing pattern and a slight reduction inW˙max.

Single-breath washouts in a rotating stretcher

2001 ◽  
Vol 90 (4) ◽  
pp. 1415-1423 ◽  
Author(s):  
M. J. Rodríguez-Nieto ◽  
G. Peces-Barba ◽  
N. González Mangado ◽  
S. Verbanck ◽  
M. Paiva
Keyword(s):  
Vital Capacity ◽  
Phase Iii ◽  
Body Postures ◽  
Single Breath ◽  
Supine Posture ◽  
Or Groups ◽  
Slope Difference ◽  
Phase Iii Slope ◽  
Prone Posture ◽  
Phase Iv

Vital capacity single-breath washouts using 90% O2-5% He-5% SF6 as a test gas mixture were performed with subjects sitting on a stool (upright) or recumbent on a stretcher (prone, supine, lateral left, lateral right, with or without rotation at end of inhalation). On the basis of the combinations of supine and prone maneuvers, gravity-dependent contributions to N2 phase III slope and N2 phase IV height in the supine posture were estimated at 18% and 68%, respectively. Whereas both He and SF6 slope decreased from supine to prone, the SF6-He slope difference actually increased ( P = 0.015). N2 phase III slopes, phase IV heights, and cardiogenic oscillations were smallest in the prone posture, and we observed similarities between the modifications of He and SF6 slopes from upright to prone and from upright to short-term microgravity. These results suggest that phase III slope is partially due to emptying patterns of small units with different ventilation-to-volume ratios, corresponding to acini or groups of acini. Of all body postures under study, the prone position most reduces the inhomogeneities of ventilation during a vital capacity maneuver at both inter- and intraregional levels.

Dynamic mechanisms determine functional residual capacity in mice, Mus musculus

1979 ◽  
Vol 46 (5) ◽  
pp. 867-871 ◽  
Author(s):  
A. Vinegar ◽  
E. E. Sinnett ◽  
D. E. Leith
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Flow Volume ◽  
Linear Portion ◽  
Volume Curve ◽  
Flow Volume Curve ◽  
Residual Capacity ◽  
Expiratory Flow ◽  
The Difference ◽  
Pentobarbital Sodium Anesthesia

Awake mice (22.6--32.6 g) were anesthetized intravenously during head-out body plethysmography. One minute after pentobarbital sodium anesthesia, tidal volume had fallen from 0.28 +/- 0.04 to 0.14 +/- 0.02 ml and frequency from 181 +/- 20 to 142 +/- 8. Functional residual capacity (FRC) decreased by 0.10 +/- 0.02 ml. Expiratory flow-volume curves were linear, highly repeatable, and submaximal over substantial portions of expiration in awake and anesthetized mice; and expiration was interrupted at substantial flows that abruptly fell to and crossed zero as inspiration interrupted relaxed expiration. FRC is maintained at a higher level in awake mice due to a higher tidal volume and frequency coupled with expiratory braking (persistent inspiratory muscle activity or increased glottal resistance). In anesthetized mice, the absence of braking, coupled with reductions in tidal volume and frequency and a prolonged expiratory period, leads to FRCs that approach relaxation volume (Vr). An equation in derived to express the difference between FRC and Vr in terms of the portion of tidal volume expired without braking, the slope of the linear portion of the expiratory flow-volume curve expressed as V/V, the time fraction of one respiratory cycle spent in unbraked expiration, and respiratory frequency.

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