| Effect of metabolic rate on ventilatory roll-off during hypoxia. | |
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MedLine Citation:
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PMID: 7928852 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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This study was done to determine 1) whether goats demonstrate the roll-off phenomenon, i.e., a secondary decrease in minute ventilation (VE), after an initial hyperventilation during various levels of hypoxia and, if so, 2) whether roll-off could be due to changes in metabolic rate. We hypothesized that roll-off occurs in the goat during hypoxia but is not due to hypometabolism. To answer question 1, eight unanesthetized adult goats were exposed to 15-20 min of hypoxia at 0.15, 0.12, and 0.09 inspired O2 fraction (FIO2), resulting in 60, 40, and 30 Torr arterial PO2, respectively. Goats were fitted with a face mask connected to a spirometer to measure VE, and arterial blood gas samples were obtained via carotid arterial catheters. Roll-off was seen with 0.15 and 0.12 FIO2, whereas VE steadily increased with 0.09 FIO2. During hypoxia, arterial PCO2 fell 2, 3, and 7 Torr at 0.15, 0.12, and 0.09 FIO2, respectively. In the second series of experiments, nine different goats were exposed to 30 min of 0.12 FIO2. O2 consumption and CO2 production were measured five times during baseline and hypoxia. VE increased to 32% above baseline values after 2 min of hypoxia and then gradually decreased by 18%. Changes in breathing frequency and tidal volume contributed to the roll-off. O2 consumption decreased (P = 0.0029, analysis of variance) and CO2 production increased (P = 0.0027) during hypoxia, although both changes were small (< 7%) compared with the eventual 18% decrease in VE. We conclude that the adult goat demonstrates the roll-off phenomenon during moderate levels of hypoxia. (ABSTRACT TRUNCATED AT 250 WORDS) |
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Authors:
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W M Gershan; H V Forster; T F Lowry; M J Korducki; A L Forster; M A Forster; P J Ohtake; E A Aaron; A K Garber |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 76 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1994 Jun |
Date Detail:
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Created Date: 1994-11-01 Completed Date: 1994-11-01 Revised Date: 2007-11-14 |
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: 2310-4 Citation Subset: IM |
Affiliation:
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Department of Pediatrics, Medical College of Wisconsin, Milwaukee 53226. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Anoxia / metabolism, physiopathology* Basal Metabolism / physiology* Blood Gas Analysis Body Temperature / physiology Carbon Dioxide / metabolism Goats Oxygen Consumption / physiology Respiratory Mechanics / physiology* Tidal Volume / physiology |
| Grant Support | |
ID/Acronym/Agency:
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HL-25739/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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124-38-9/Carbon Dioxide |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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