[abstract] DCS RISKS IN GROUND-BASED HYPOBARIC TRIALS VS. EXTRAVEHICULAR ACTIVITY

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[abstract] DCS RISKS IN GROUND-BASED HYPOBARIC TRIALS VS. EXTRAVEHICULAR ACTIVITY

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dc.contributor.author Gernhardt, ML en_US
dc.contributor.author Conkin, J en_US
dc.contributor.author Vann, RD en_US
dc.contributor.author Pollock, NW en_US
dc.contributor.author Feiveson, AH en_US
dc.date.accessioned 2006-08-21T03:32:46Z
dc.date.available 2006-08-21T03:32:46Z
dc.date.issued 2004 en_US
dc.identifier.other Undersea Hyp Med 2004 en_US
dc.identifier.uri http://archive.rubicon-foundation.org/1537
dc.description Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org ) en_US
dc.description.abstract BACKGROUND: Significant differences were observed in DCS incidence during ground trials (GT=8/35) and extravehicular activity (EVA) (EVA=0/141) using Shuttle prebreathe protocols (Fisher Exact Test [FET] p less than 0.05). Factors potentially contributing to the lower EVA risk include enhanced nitrogen elimination (cardiovascular/respiratory dynamics and/or safety margins incorporated into routinely longer operational prebreathes [mean time at 10.2 psi greater than 42 hrs for EVA vs. 12 hrs for GT]) and decreased nuclei formation (reductions in weight-bearing and/or joint motions in the space suit). METHODS: Differences between flight and ground tests were reviewed to develop an improved ground test bed, incorporating semi-recumbent, non-ambulatory subjects performing EVA simulations with reduced joint motions representative of EVA activity. Light prebreathe metabolic exercise (~5.9 mL kg-1 min-1), simulating normal in-suit metabolic overhead, was added to some protocols. Two-hundred-twenty test subjects performed 7 different protocols using the new test bed. Logistic Regression models (LRM) developed using recent ground test data were used to predict the "as flown" Shuttle EVA DCS risk. RESULTS: Of the 7 protocols tested only one met the conditions for acceptability for flight (Phase II). There have been no reports of DCS in 34 EVA uses of this protocol from the International Space Station (no significant difference between EVA and GT, p greater than 0.05 FET)). The LRM predicted risk of the "as flown" Shuttle protocols is within the 95percent CI of the EVA incidence. CONCLUSION: The current NASA ground tests and predictive models are more representative of EVA than previous ground tests. Ground testing remains an important step in identifying acceptable prebreathe protocols. More research is needed to understand the individual contributions of the variables affecting suited microgravity DCS risk. en_US
dc.language.iso en_US
dc.rights Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org ) en_US
dc.subject decompression en_US
dc.subject exercise en_US
dc.subject nitrogen en_US
dc.subject DCI en_US
dc.subject DCS en_US
dc.subject environment en_US
dc.subject space en_US
dc.subject human en_US
dc.subject NASA en_US
dc.title [abstract] DCS RISKS IN GROUND-BASED HYPOBARIC TRIALS VS. EXTRAVEHICULAR ACTIVITY en_US

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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