Lung function changes of divers after single deep heliox diving

AbstractObjectivesThis study detects the changes in pulmonary function of divers after 80m, 100 m, and 120 m helium-oxygen (heliox) dive. Methods: A total of 26 divers participated in the experiment, of which 15 divers performed the 80m dive, 5 divers performed the 100m dive, and 6 divers performed the 120m dive. The exposure phases included breathing heliox or air in water and O2 in the hyperbaric chamber. Pulmonary function (forced flow-volume) was measured twice before diving, within 30 minutes after diving, and 24 hours after diving. The parameters examined were forced vital capacity (FVC), forced expired volume in 1 second (FEV1), forced expired flow from 25% to 75% volume expired (FEF25-75%), 25-75 percent maximum expiratory flow as compared with vital capacity (MEF 25-75%) and peak expiratory flow (PEF). Results: FEV1/FVC and MEF25% markedly decreased (p = 0.0395, p = 0.0496) within 30min after the 80m dive, but returned to base values at 24h after the dive. Other indicators showed a downward trend within 30min after 80m heliox diving (no statistical difference). Interestingly, FEV1, FEV1/FVC, PEF, MEF decreased after 100m heliox dives, but there was no statistical difference. However, in the 120m heliox dive, FEV1/FVC and MEF75% significantly decreased again after diving (p = 0.0098, p = 0.0073). The relatively small number and more proficient diving skills of divers in 100m and 120m diving may be responsible for the inconsistent results. But when the diving depth reached 120m, results again showed a significant statistical change. Conclusion: Single deep heliox diving can cause temporary expiratory and small airway dysfunction, which can be recovered at 24h after diving.

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Maximum expiratory flow and transpulmonary pressure in the hamster

Journal of Applied Physiology ◽

10.1152/jappl.1978.45.6.840 ◽

1978 ◽

Vol 45 (6) ◽

pp. 840-845 ◽

Cited By ~ 10

Author(s):

E. C. Lucey ◽

B. R. Celli ◽

G. L. Snider

Keyword(s):

Vital Capacity ◽

Simple Technique ◽

Transpulmonary Pressure ◽

Esophageal Pressure ◽

Flow Limitation ◽

Flow Volume ◽

System Pressure ◽

Pleural Surface ◽

Maximum Expiratory Flow ◽

Expiratory Flow

Maximum expiratory flow was measured in 19 normal, anesthetized, tracheostomized, supine hamsters from records of forced deflation produced by the application of varying degrees of negative pressure to the tracheostomies of animals whose lungs had been previously inflated to a transpulmonary pressure (PL) of 25 cmH2O. Flow was measured with a pneumotachograph, volume with a constant-volume pressure plethysmograph and pleural surface pressure (Ppl) with a water-filled esophageal catheter. The esophageal pressure measurement overestimated Ppl and a simple technique was based on an estimate of the resting volume of the chest wall. This volume, at which the Ppl is zero, was calculated for anesthetized supine hamsters from the measurement of respiratory-system pressure and PL made independently of esophageal pressure and was found to be about 30% of vital capacity (VC). Flow limitation was present below 70% of VC with a tracheal deflation pressure of -30cmH2O. Negative effort dependence of flow was seen in small segments of the flow-volume curves. Mean +/- SD maximum expiratory flow at 50% VC was 52 +/- 9.5 ml/s or 9.1 VC/s. Upstream resistance was 0.09 +/- 0.03 cmH2O/ml per s.

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Maximum expiratory flow-volume curves during short periods of microgravity

Journal of Applied Physiology ◽

10.1152/jappl.1991.70.6.2587 ◽

1991 ◽

Vol 70 (6) ◽

pp. 2587-2596 ◽

Cited By ~ 10

Author(s):

H. J. Guy ◽

G. K. Prisk ◽

A. R. Elliott ◽

J. B. West

Keyword(s):

Vital Capacity ◽

Normal Subjects ◽

Flow Volume ◽

Elastic Recoil ◽

Microgravity Research ◽

Maximum Expiratory Flow ◽

Research Aircraft ◽

The Mean ◽

Expiratory Flow ◽

The Individual

To elucidate the effect of normal gravitation on the shape of the maximum expiratory flow-volume (MEFV) curve, we studied nine normal subjects in a National Aeronautics and Space Administration microgravity research aircraft. They performed multiple MEFV maneuvers at 0, 1, and approximately 2 G. The MEFV curves for each subject were filtered, aligned at residual volume, and ensemble averaged to produce an average MEFV curve for each state, allowing differences to be studied. Most subjects showed a decrease in the forced vital capacity at 0 G, which we attribute to an increased intrathoracic blood volume. In most of these subjects, the mean lung volume associated with a given flow was lower at 0 G over about the upper half of the vital capacity. This is similar to the change previously reported during headout immersion and is consistent with the known effect of engorgement of the lung with blood on elastic recoil. There were also consistent but highly individual changes in the position and magnitude of detailed features of the curve, the individual patterns being similar to those previously reported on transition from the erect to the supine position. This supports the idea that the location and motion of choke points that determine the detailed individual configuration of MEFV curves can be significantly influenced by gravitational forces, presumably via the effects of change in longitudinal tension on local airway pressure-diameter behavior and thus wave speed.

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Forced expirations and maximum expiratory flow-volume curves during sustained microgravity on SLS-1

Journal of Applied Physiology ◽

10.1152/jappl.1996.81.1.33 ◽

1996 ◽

Vol 81 (1) ◽

pp. 33-43 ◽

Cited By ~ 22

Author(s):

A. R. Elliott ◽

G. K. Prisk ◽

H. J. Guy ◽

J. M. Kosonen ◽

J. B. West

Keyword(s):

Forced Vital Capacity ◽

Vital Capacity ◽

Forced Expiratory Volume ◽

Slight Reduction ◽

Flow Volume ◽

Lung Volumes ◽

Volume Curve ◽

Supine Posture ◽

Maximum Expiratory Flow ◽

Expiratory Flow

Gravity is known to influence the mechanical behavior of the lung and chest wall. However, the effect of sustained microgravity (microG) on forced expirations has not previously been reported. Tests were carried out by four subjects in both the standing and supine postures during each of seven preflight and four postflight data-collection sessions and four times during the 9 days of microG exposure on Spacelab Life Sciences-1. Compared with preflight standing values, peak expiratory flow rate (PEFR) was significantly reduced by 12.5% on flight day 2 (FD2), 11.6% on FD4, and 5.0% on FD5 but returned to standing values by FD9. The supine posture caused a 9% reduction in PEFR. Forced vital capacity and forced expired volume in 1 s were slightly reduced (approximately 3-4%) on FD2 but returned to preflight standing values on FD4 and FD5, and by FD9 both values were slightly but significantly greater than standing values. Forced vital capacity and forced expiratory volume in 1 s were both reduced in the supine posture (approximately 8-10%). Forced expiratory flows at 50% and between 25 and 75% of vital capacity did not change during microG but were reduced in the supine posture. Analysis of the maximum expiratory flow-volume curve showed that microG caused no consistent change in the curve configuration when individual in-flight days were compared with preflight standing curves, although two subjects did show a slight reduction in flows at low lung volumes from FD2 to FD9. The interpretation of the lack of change in curve configuration must be made cautiously because the lung volumes varied from day to day in flight. Therefore, the flows at absolute lung volumes in microG and preflight standing are not being compared. The supine curves showed a subtle but consistent reduction in flows at low lung volumes. The mechanism responsible for the reduction in PEFR is not clear. It could be due to a lack of physical stabilization when performing the maneuver in the absence of gravity or a transient reduction in respiratory muscle strength.

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Increased gravitational stress does not alter maximum expiratory flow

Journal of Applied Physiology ◽

10.1152/jappl.1985.59.1.28 ◽

1985 ◽

Vol 59 (1) ◽

pp. 28-33 ◽

Cited By ~ 3

Author(s):

D. Pyszczynski ◽

S. N. Mink ◽

N. R. Anthonisen

Keyword(s):

Vital Capacity ◽

Total Lung Capacity ◽

Maximum Flow ◽

Flow Volume ◽

Lung Capacity ◽

Gravitational Stress ◽

Regional Lung ◽

Maximum Expiratory Flow ◽

Expiratory Flow ◽

Capacity Data

We measured maximum expiratory flow-volume (MEFV) curves in six seated subjects during normal (+1 Gz) and increased (+2 and +3 Gz) gravitational stress. Full MEFV curves, initiated at total lung capacity, were recorded, as were partial MEFV curves, initiated at approximately 60% of the vital capacity. Data were acquired in all subjects breathing air at +1 and +2 Gz; results were available for three subjects breathing 80% He-20% O2 at +1 and +2 Gz, and in two subjects, results were obtained at +3 Gz. Changes in gravitational stress were not associated with changes of either full or partial MEFV curves. The known increase in differences of regional lung volume and recoil caused by increased gravitational stress did not influence maximum expiratory flow. Though increased gravitational stress probably changed regional emptying sequences little during full MEFV maneuvers, substantial changes of emptying sequence were expected during partial maneuvers. It is possible that such changes in emptying sequence occurred but were not associated with changes in maximum flow because the latter was determined by choking in central airways common to all regions.

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Computerized method for analyzing maximum and partial expiratory flow-volume curves

Journal of Applied Physiology ◽

10.1152/jappl.1975.39.2.315 ◽

1975 ◽

Vol 39 (2) ◽

pp. 315-317 ◽

Cited By ~ 7

Author(s):

R. J. Soto ◽

H. V. Forster ◽

B. Rasmussen

Keyword(s):

Pilot Study ◽

Flow Rate ◽

Magnetic Tape ◽

Peak Expiratory Flow Rate ◽

Vital Capacity ◽

Reliability And Validity ◽

Flow Volume ◽

Maximum Expiratory Flow ◽

Expiratory Flow ◽

Computerized System

Computerized instrumentation and software have been developed to obtain maximum expiratory flow-volume (MEFV) and partial expiratory flow-volume (PEFV) curves. The computerized system calculates and prints out the flow at 25% and 40% of control vital capacity (VC), the expiratory volume, peak expiratory flow rate and expiratory volume at one second (FEV1) divided by VC, the latter expressed as a percent. The flow-volume curves can be displayed on an oscilloscope or plotter and stored on magnetic tape. A pilot study was completed to demonstrate the reliability and validity of the data obtained.

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Changes in regional emptying sequence need not change maximum expiratory flow

Journal of Applied Physiology ◽

10.1152/jappl.1986.60.6.1834 ◽

1986 ◽

Vol 60 (6) ◽

pp. 1834-1838 ◽

Cited By ~ 1

Author(s):

R. B. Filuk ◽

N. R. Anthonisen

Keyword(s):

Vital Capacity ◽

Total Lung Capacity ◽

Young Men ◽

Forced Expiration ◽

Flow Volume ◽

Lung Volumes ◽

Lung Capacity ◽

Maximum Expiratory Flow ◽

Expiratory Flow

Nine normal young men inhaled boluses of He at the onset of slow vital capacity (VC) inspirations. During the subsequent VC expirations, we measured expired flow, volume, and He concentrations. Expirations consisted of full or partial maximum expiratory flow-volume (MEFV) maneuvers. Full maneuvers were forced expirations from total lung capacity (TLC). Partial maneuvers were accomplished by expiring slowly from TLC to 70, 60, 50, and 40% VC and then initiating forced expiration. Expired He concentrations from full and partial maneuvers were compared with each other and with those resulting from slow expirations. At comparable volumes less than 50% VC, flow during partial and full MEFV maneuvers did not differ. Expired He concentrations were higher during partial maneuvers than during full ones; at the onset of partial maneuvers upper zone emptying predominated, whereas this was not the case at the same lung volumes during maneuvers initiated at TLC. We observed substantial differences in regional emptying sequence that did not influence maximum expiratory flow.

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Analysis of Maximum Expiratory Flow Volume Curves Using Canonical Correlation Analysis

Methods of Information in Medicine ◽

10.1055/s-0038-1635359 ◽

1985 ◽

Vol 24 (02) ◽

pp. 91-100 ◽

Cited By ~ 3

Author(s):

W. van Pelt ◽

Ph. H. Quanjer ◽

M. E. Wise ◽

E. van der Burg ◽

R. van der Lende

Keyword(s):

Correlation Analysis ◽

Canonical Correlation Analysis ◽

Canonical Correlation ◽

Flow Volume ◽

Non Linear ◽

Maximum Expiratory Flow ◽

Expiratory Flow ◽

Relationship Of ◽

The Relationship ◽

Age And Sex

SummaryAs part of a population study on chronic lung disease in the Netherlands, an investigation is made of the relationship of both age and sex with indices describing the maximum expiratory flow-volume (MEFV) curve. To determine the relationship, non-linear canonical correlation was used as realized in the computer program CANALS, a combination of ordinary canonical correlation analysis (CCA) and non-linear transformations of the variables. This method enhances the generality of the relationship to be found and has the advantage of showing the relative importance of categories or ranges within a variable with respect to that relationship. The above is exemplified by describing the relationship of age and sex with variables concerning respiratory symptoms and smoking habits. The analysis of age and sex with MEFV curve indices shows that non-linear canonical correlation analysis is an efficient tool in analysing size and shape of the MEFV curve and can be used to derive parameters concerning the whole curve.

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Pattern and mechanism of airway response to hypocapnia in normal subjects

Journal of Applied Physiology ◽

10.1152/jappl.1979.47.1.8 ◽

1979 ◽

Vol 47 (1) ◽

pp. 8-12 ◽

Cited By ~ 35

Author(s):

C. F. O'Cain ◽

M. J. Hensley ◽

E. R. McFadden ◽

R. H. Ingram

Keyword(s):

Vital Capacity ◽

Normal Subjects ◽

Oxygen Mixture ◽

Flow Volume ◽

Mixture Density ◽

Lung Capacity ◽

Airway Constriction ◽

Maximal Expiratory Flow ◽

Airway Response ◽

Expiratory Flow

We examined the bronchoconstriction produced by airway hypocapnia in normal subjects. Maximal expiratory flow at 25% vital capacity on partial expiratory flow-volume (PEFV) curves fell during hypocapnia both on air and on an 80% helium- 20% oxygen mixture. Density dependence also fell, suggesting predominantly small airway constriction. The changes seen on PEFV curves were not found on maximal expiratory flow-volume curves, indicating the inhalation to total lung capacity substantially reversed the constriction. Pretreatment with a beta-sympathomimetic agent blocked the response, whereas atropine pretreatment did not, suggesting that hypocapnia affects airway smooth muscle directly, not via cholinergic efferents.

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Pulmonary function in men after oxygen breathing at 3.0 ATA for 3.5 h

Journal of Applied Physiology ◽

10.1152/jappl.1991.71.3.878 ◽

1991 ◽

Vol 71 (3) ◽

pp. 878-885 ◽

Cited By ~ 24

Author(s):

J. M. Clark ◽

R. M. Jackson ◽

C. J. Lambertsen ◽

R. Gelfand ◽

W. D. Hiller ◽

...

Keyword(s):

Pulmonary Function ◽

Forced Vital Capacity ◽

Vital Capacity ◽

Large Change ◽

Forced Expiratory Volume ◽

Diffusing Capacity ◽

Mild Degree ◽

Oxygen Breathing ◽

Multiple Organs ◽

Expiratory Flow

As a pulmonary component of Predictive Studies V, designed to determine O2 tolerance of multiple organs and systems in humans at 3.0–1.5 ATA, pulmonary function was evaluated at 1.0 ATA in 13 healthy men before and after O2 exposure at 3.0 ATA for 3.5 h. Measurements included flow-volume loops, spirometry, and airway resistance (Raw) (n = 12); CO diffusing capacity (n = 11); closing volumes (n = 6); and air vs. HeO2 forced vital capacity maneuvers (n = 5). Chest discomfort, cough, and dyspnea were experienced during exposure in mild degree by most subjects. Mean forced expiratory volume in 1 s (FEV1) and forced expiratory flow at 25–75% of vital capacity (FEF25–75) were significantly reduced postexposure by 5.9 and 11.8%, respectively, whereas forced vital capacity was not significantly changed. The average difference in maximum midexpiratory flow rates at 50% vital capacity on air and HeO2 was significantly reduced postexposure by 18%. Raw and CO diffusing capacity were not changed postexposure. The relatively large change in FEF25–75 compared with FEV1, the reduction in density dependence of flow, and the normal Raw postexposure are all consistent with flow limitation in peripheral airways as a major cause of the observed reduction in expiratory flow. Postexposure pulmonary function changes in one subject who convulsed at 3.0 h of exposure are compared with corresponding average changes in 12 subjects who did not convulse.

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