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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1992-3-30
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pubmed:abstractText |
Water immersion can cause airways closure during tidal breathing, and his may result in areas of low ventilation-perfusion (VA/Q) ratios (VA/Q less than or equal to 0.1) and/or shunt and, ultimately, hypoxemia. We studied this in 12 normal males: 6 young (Y; aged 20-29 yr) with closing volume (CV) less than expiratory reserve volume (ERV), and six older (O; aged 40-54 yr) with CV greater than ERV during seated head-out immersion. Arterial and expired inert gas concentrations and dye-dilution cardiac output (Q) were measured before and at 2, 5, 10, 15, and 20 min in 35 degrees C water. During immersion, Y showed increases in expired minute ventilation (VE; 8.3-10.3 l/min), Q (6.1-8.2 l/min), and arterial PO2 (PaO2; 91-98 Torr; P less than or equal to 0.05). However, O2 uptake (VO2), shunt, amount of low-VA/Q areas (% of Q), and the log standard deviation of the perfusion distribution (log SDQ) were unchanged. During immersion, O showed increases in shunt (0.6-1.8% of Q), VE (8.5-11.4 l/min), and VO2 (0.31-0.40 l/min) but showed no change in low-VA/Q areas, log SDQ, Q, or PaO2. Throughout, O showed more VA/Q inequality (greater log SDQ) than Y (O, 0.69 vs. Y, 0.47).(ABSTRACT TRUNCATED AT 250 WORDS)
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pubmed:grant | |
pubmed:keyword | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Jan
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pubmed:issn |
8750-7587
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
72
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
64-72
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:1311293-Adult,
pubmed-meshheading:1311293-Carbon Dioxide,
pubmed-meshheading:1311293-Cardiac Output,
pubmed-meshheading:1311293-Humans,
pubmed-meshheading:1311293-Immersion,
pubmed-meshheading:1311293-Lung Volume Measurements,
pubmed-meshheading:1311293-Male,
pubmed-meshheading:1311293-Middle Aged,
pubmed-meshheading:1311293-Noble Gases,
pubmed-meshheading:1311293-Oxygen,
pubmed-meshheading:1311293-Ventilation-Perfusion Ratio
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pubmed:year |
1992
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pubmed:articleTitle |
Ventilation-perfusion relationships in the lung during head-out water immersion.
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pubmed:affiliation |
Department of Medicine, University of California San Diego, La Jolla 92093-0623.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.,
Research Support, Non-U.S. Gov't
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