Source:http://linkedlifedata.com/resource/pubmed/id/14672971
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
4
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pubmed:dateCreated |
2004-3-12
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pubmed:abstractText |
Increased gravity impairs pulmonary distributions of ventilation and perfusion. We sought to develop a method for rapid, simultaneous, and noninvasive assessments of ventilation and perfusion distributions during a short-duration hypergravity exposure. Nine sitting subjects were exposed to one, two, and three times normal gravity (1, 2, and 3 G) in the head-to-feet direction and performed a rebreathing and a single-breath washout maneuver with a gas mixture containing C(2)H(2), O(2), and Ar. Expirograms were analyzed for cardiogenic oscillations (COS) and for phase IV amplitude to analyze inhomogeneities in ventilation (Ar) and perfusion [CO(2)-to-Ar ratio (CO(2)/Ar)] distribution, respectively. COS were normalized for changes in stroke volume. COS for Ar increased from 1-G control to 128 +/- 6% (mean +/- SE) at 2 G (P = 0.02 for 1 vs. 2 G) and 165 +/- 13% at 3 G (P = 0.002 for 2 vs. 3 G). Corresponding values for CO(2)/Ar were 135 +/- 12% (P = 0.04) and 146 +/- 13%. Phase IV amplitude for Ar increased to 193 +/- 39% (P = 0.008) at 2 G and 229 +/- 51% at 3 G compared with 1 G. Corresponding values for CO(2)/Ar were 188 +/- 29% (P = 0.02) and 219 +/- 18%. We conclude that not only large-scale ventilation and perfusion inhomogeneities, as reflected by phase IV amplitude, but also smaller-scale inhomogeneities, as reflected by the ratio of COS to stroke volume, increase with hypergravity. Except for small-scale ventilation distribution, most of the impairments observed at 3 G had been attained at 2 G. For some of the parameters and gravity levels, previous comparable data support the present simplified method.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
8750-7587
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
96
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1470-7
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pubmed:dateRevised |
2008-11-21
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pubmed:meshHeading |
pubmed-meshheading:14672971-Adult,
pubmed-meshheading:14672971-Female,
pubmed-meshheading:14672971-Heart,
pubmed-meshheading:14672971-Humans,
pubmed-meshheading:14672971-Hypergravity,
pubmed-meshheading:14672971-Lung,
pubmed-meshheading:14672971-Male,
pubmed-meshheading:14672971-Methods,
pubmed-meshheading:14672971-Oscillometry,
pubmed-meshheading:14672971-Posture,
pubmed-meshheading:14672971-Pulmonary Circulation,
pubmed-meshheading:14672971-Respiratory Physiological Phenomena,
pubmed-meshheading:14672971-Stroke Volume,
pubmed-meshheading:14672971-Ventilation-Perfusion Ratio
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pubmed:year |
2004
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pubmed:articleTitle |
Effects of hypergravity on the distributions of lung ventilation and perfusion in sitting humans assessed with a simple two-step maneuver.
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pubmed:affiliation |
Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden. Malin.Rohdin@fyfa.ki.se
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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