| Lower body adynamia as a factor to reduce the risk of hypobaric decompression sickness. | |
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MedLine Citation:
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PMID: 11277286 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: We define lower body adynamia (LBA) as restricted lower body movement, particularly walking, during both the denitrogenation phase at site pressure and during the exercise phase while at altitude. HYPOTHESIS: Our null hypothesis is that subjects who are adynamic in the lower body but do upper body exercise will be at similar risk of decompression sickness (DCS) and venous gas emboli (VGE) as subjects who randomly walk but do no planned exercise while at altitude. METHODS: We selected a data set that contained 1401 altitude exposures with the following conditions: a) walking was part of the exercise at altitude; or b) there was no planned exercise done at altitude but walking was not restricted; or c) LBA was inforced, but upper body exercise was done at altitude. We used logistic regression (LR) on all 1401 exposures, a log logistic survival analysis (SA) on a subset of data from "a" and "c" (n = 234), and estimated a model for how the incidence of VGE changes through time. RESULTS: The estimated probabilities of DCS and VGE with 95% confidence intervals (Cls) from the LR with a simulation of a 3-h oxygen prebreathe, a 4-h exposure to 4.3 psia in a male, and exercise and LBA conditions as described above are: (see text). CONCLUSION: LBA that includes upper body exercise appears to be as protective against DCS and VGE as random walking by subjects who did no prescribed exercise while at altitude, and is more protective than exercise that included walking. Our conclusions are based on an assumption that we have adequately controlled, through our data selection process and the use of multivariable models, important variables in tests that were not done at the Johnson Space Center. |
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Authors:
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J Conkin; M R Powell |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
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Title: Aviation, space, and environmental medicine Volume: 72 ISSN: 0095-6562 ISO Abbreviation: Aviat Space Environ Med Publication Date: 2001 Mar |
Date Detail:
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Created Date: 2001-03-29 Completed Date: 2001-05-17 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 7501714 Medline TA: Aviat Space Environ Med Country: United States |
Other Details:
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Languages: eng Pagination: 202-14 Citation Subset: IM; S |
Affiliation:
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Life Sciences Research Laboratories, NASA-Johnson Space Center, Houston, TX, USA. jconkin@ems.jsc.nasa.gov |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Cardiac Volume
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physiology Cardiovascular System / physiopathology* Cell Membrane Permeability / physiology Confidence Intervals Decompression Sickness / etiology, prevention & control* Embolism, Air / etiology, prevention & control* Female Humans Logistic Models Lower Body Negative Pressure* Male Models, Biological* Nitrogen / metabolism Odds Ratio Survival Analysis |
| Chemical | |
Reg. No./Substance:
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7727-37-9/Nitrogen |
| Investigator | |
Investigator/Affiliation:
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M R Powell / NASA JSC |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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