Document Detail

Effects of hyperoxia on ventilation and pulmonary hemodynamics during immersed prone exercise at 4.7 ATA: possible implications for immersion pulmonary edema.
MedLine Citation:
PMID:  20431020     Owner:  NLM     Status:  MEDLINE    
Immersion pulmonary edema (IPE) can occur in otherwise healthy swimmers and divers, likely because of stress failure of pulmonary capillaries secondary to increased pulmonary vascular pressures. Prior studies have revealed progressive increase in ventilation [minute ventilation (Ve)] during prolonged immersed exercise. We hypothesized that this increase occurs because of development of metabolic acidosis with concomitant rise in mean pulmonary artery pressure (MPAP) and that hyperoxia attenuates this increase. Ten subjects were studied at rest and during 16 min of exercise submersed at 1 atm absolute (ATA) breathing air and at 4.7 ATA in normoxia and hyperoxia [inspired P(O(2)) (Pi(O(2))) 1.75 ATA]. Ve increased from early (E, 6th minute) to late (L, 16th minute) exercise at 1 ATA (64.1 +/- 8.6 to 71.7 +/- 10.9 l/min BTPS; P < 0.001), with no change in arterial pH or Pco(2). MPAP decreased from E to L at 1 ATA (26.7 +/- 5.8 to 22.7 +/- 5.2 mmHg; P = 0.003). Ve and MPAP did not change from E to L at 4.7 ATA. Hyperoxia reduced Ve (62.6 +/- 10.5 to 53.1 +/- 6.1 l/min BTPS; P < 0.0001) and MPAP (29.7 +/- 7.4 to 25.1 +/- 5.7 mmHg, P = 0.002). Variability in MPAP among subjects was wide (range 14.1-42.1 mmHg during surface and depth exercise). Alveolar-arterial Po(2) difference increased from E to L in normoxia, consistent with increased lung water. We conclude that increased Ve at 1 ATA is not due to acidosis and is more consistent with respiratory muscle fatigue and that progressive pulmonary vascular hypertension does not occur during prolonged immersed exercise. Wide variation in MPAP among healthy subjects is consistent with variable individual susceptibility to IPE.
Dionne F Peacher; Shelly R H Pecorella; John J Freiberger; Michael J Natoli; Eric A Schinazi; P Owen Doar; Albert E Boso; Aaron J Walker; Matthew Gill; Dawn Kernagis; Donna Uguccioni; Richard E Moon
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2010-04-29
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  109     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-06-30     Completed Date:  2010-10-14     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  68-78     Citation Subset:  IM    
Center for Hyperbaric Medicine and Environmental Physiology, Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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MeSH Terms
Carbon Dioxide / blood
Diving / physiology
Exercise / physiology
Hemodynamics / physiology*
Hydrogen-Ion Concentration
Hyperoxia / physiopathology*
Immersion / physiopathology*
Oxygen / blood
Oxygen Consumption / physiology
Partial Pressure
Prone Position / physiology
Pulmonary Artery / physiology
Pulmonary Edema / physiopathology*
Pulmonary Ventilation / physiology*
Swimming / physiology*
Vital Capacity / physiology
Young Adult
Grant Support
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

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