Document Detail

Enhancement of preoxygenation for decompression sickness protection: effect of exercise duration.
MedLine Citation:
PMID:  12498543     Owner:  NLM     Status:  MEDLINE    
INTRODUCTION: Since strenuous exercise for 10 min during preoxygenation was shown to provide better protection from decompression sickness (DCS) incidence than resting preoxygenation, a logical question was: would a longer period of strenuous exercise improve protection even further? HYPOTHESIS: Increased strenuous exercise duration during preoxygenation increases DCS protection. METHODS: There were 60 subjects, 30 men and 30 women, who were exposed to 9,144 m (4.3 psia) for 4 h while performing mild, upper body exercise. Before the exposures, each subject performed three preoxygenation profiles on different days in balanced order: a 90-min resting preoxygenation control; a 240-min resting preoxygenation control; and a 90-min preoxygenation including exercise during the first 15 min. The subjects were monitored at altitude for venous gas emboli (VGE) with an echo-imaging system and observed for signs and symptoms of DCS. RESULTS: There were no significant differences in occurrence of DCS following any of the three preoxygenation procedures. Results were also comparable to an earlier report of 42% DCS with a 60-min preoxygenation including a 10-min exercise. There was no difference between VGE incidence in the comparison of protection offered by a 90-min preoxygenation with or without 13 min of strenuous exercise. The DCS incidence following a 240-min resting preoxygenation, 40%, was higher than observed during NASA studies and nearly identical with the earlier 42% DCS after a 60-min preoxygenation including exercise during the first 10 min. CONCLUSION: The protection offered by a 10 min exercise in a 60-min preoxygenation was not increased with extension of the preoxygenation exercise period to 15 min in a 90-min preoxygenation, indicating an upper time limit to the beneficial effects of strenuous exercise.
James T Webb; Andrew A Pilmanis; Michele D Fischer; Nandini Kannan
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Aviation, space, and environmental medicine     Volume:  73     ISSN:  0095-6562     ISO Abbreviation:  Aviat Space Environ Med     Publication Date:  2002 Dec 
Date Detail:
Created Date:  2002-12-24     Completed Date:  2003-01-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7501714     Medline TA:  Aviat Space Environ Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1161-6     Citation Subset:  IM; S    
Air Force Research Laboratory, [Wyle Laboratories, Life Sciences, Systems, and Services] Brooks AFB, San Antonio, TX 78232, USA.
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MeSH Terms
Decompression Sickness / prevention & control*
Exercise Test
Oxygen Inhalation Therapy / methods*
Time Factors
A A Pilmanis / Brooks AFB, San Antonio, TX

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