| Distributions of lung ventilation and perfusion in prone and supine humans exposed to hypergravity. | |
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MedLine Citation:
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PMID: 15047673 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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When normal subjects are exposed to hypergravity [5 times normal gravity (5 G)] there is an impaired arterial oxygenation that is less severe in the prone compared with supine posture. We hypothesized that under these conditions the heterogeneities of ventilation and/or perfusion distributions would be less prominent when subjects were prone compared with supine. Expirograms from a combined rebreathing-single breath washout maneuver (Rohdin M, Sundblad P, and Linnarsson D. J Appl Physiol 96: 1470-1477, 2004) were analyzed for vital capacity (VC), phase III slope, and phase IV amplitude, to analyze heterogeneities in ventilation (Ar) and perfusion [CO(2)-to-Ar ratio (CO(2)/Ar)] distribution, respectively. During hypergravity, VC decreased more in the supine than in the prone position (ANOVA, P = 0.02). Phase III slope was more positive for Ar (P = 0.003) and more negative for CO(2)/Ar (P = 0.007) in the supine compared with prone posture at 5 G, in agreement with the notion of a more severe hypergravity-induced ventilation-perfusion mismatch in supine posture. Phase IV amplitude became lower in the supine than in the prone posture for both Ar (P = 0.02) and CO(2)/Ar (P = 0.004) during hypergravity as a result of the more reduced VC in the supine posture. We speculate that results of VC and phase IV amplitude are due to the differences in heart-lung interaction and diaphragm position between postures: a stable position of the heart and diaphragm in prone hypergravity, in contrast to supine in which the weight of the heart and a cephalad shift of the diaphragm compress lung tissue. |
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Authors:
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M Rohdin; J Petersson; M Mure; R W Glenny; S G E Lindahl; D Linnarsson |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2004-03-26 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 97 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2004 Aug |
Date Detail:
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Created Date: 2004-07-12 Completed Date: 2005-01-14 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 675-82 Citation Subset: IM; S |
Affiliation:
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Section of Environmental Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden. malin.rohdin@fyfa.ki.se |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Diaphragm / physiology Female Heart / physiology Humans Hypergravity / adverse effects* Lung / physiology* Male Posture / physiology* Prone Position Pulmonary Gas Exchange / physiology Supine Position |
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