Document Detail


The risk of altitude decompression sickness at 12,000 m and the effect of ascent rate.
MedLine Citation:
PMID:  14556566     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
INTRODUCTION: Loss of aircraft cabin pressurization can result in very rapid decompression rates. The literature contains reports of increased or unchanged levels of altitude decompression sickness (DCS) resulting from increasing the rate of decompression. We conducted two prospective exposure profiles to quantify the DCS risk at 12,192 m (40,000 ft), and to determine if there was a greater DCS hazard associated with a much higher rate of decompression than typically used during past DCS studies. METHODS: The 63 human subjects participated in 80 altitude chamber decompression exposures to a simulated altitude of 12,192 m (2.72 psia; 18.75 kPa) for 90 min, following preoxygenation with 100% oxygen for 90 min. Half of the subject-exposures involved an 8-min decompression (1,524 mpm; 5,000 fpm) and the other half experienced a 30-s decompression (mean of 24,384 mpm; 80,000 fpm). Throughout each ascent and exposure, subjects were seated at rest and breathed 100% oxygen. At altitude, they were monitored for precordial venous gas emboli (VGE) and DCS symptoms. RESULTS: The higher decompression rate yielded 55.0% DCS and 72.5% VGE and the lower rate produced 47.5% DCS and 65.0% VGE. Chi square and log rank tests based on the Kaplan-Meier analyses indicated no difference in the incidence or onset rate of DCS or VGE observed during the two profiles. CONCLUSION: Decompression rate to altitude up to 24,384 mpm was found not to have an effect on DCS risk at altitude. However, research is needed to define the DCS risk with decompression rates greater than 24,384 mpm. It was also found that the onset time to DCS symptoms decreases as altitude increases.
Authors:
Andrew A Pilmanis; James T Webb; Nandini Kannan; Ulf I Balldin
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Aviation, space, and environmental medicine     Volume:  74     ISSN:  0095-6562     ISO Abbreviation:  Aviat Space Environ Med     Publication Date:  2003 Oct 
Date Detail:
Created Date:  2003-10-14     Completed Date:  2004-01-20     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:  1052-7     Citation Subset:  IM; S    
Affiliation:
Air Force Research Laboratory, 2485 Gillingham Drive, Brooks City-Base, TX 78235-5105, USA. andrew.pilmanis@brooks.af.mil
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MeSH Terms
Descriptor/Qualifier:
Adult
Aircraft*
Altitude*
Decompression Sickness / physiopathology*
Embolism, Air / physiopathology
Female
Humans
Male
Prospective Studies
Risk Factors

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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