Document Detail

Pulmonary response to 3 h of hypoxia in prone pigs.
MedLine Citation:
PMID:  17804304     Owner:  NLM     Status:  MEDLINE    
Studies in whole animals, isolated lungs and pulmonary tissue strips have shown that the pulmonary vascular resistance (PVR) to hypoxia is temporally biphasic in nature. We studied the regional temporal response to hypoxia in prone pigs. The animals were ventilated with an FIO2 of 0.21 (control), followed by an FIO2 of 0.12 for 180 min. A biphasic response in P(pa) to hypoxia was seen with the first peak between 10 and 20 min and a second rise in P(pa) starting after 30 min, which was due to an increase in cardiac output. Regional blood flow (Q ) and ventilation (V (A)) were measured using i.v. infusion of 15 microm and inhalation of 1 microm fluorescent microspheres, respectively. We grouped the lung pieces according to their temporal relative flow response to hypoxia. The five groups were each spatially distributed similarly, but not identically, among the animals. The corresponding relative ventilation to each group did not vary much. We conclude that in the prone pig, the PVR response to sustained hypoxia varies among regions of the lungs. Following an initial rise in PVR in most lung pieces, we found unexpectedly that some regions continue to increase PVR progressively and while other regions decrease PVR after the initial increase. The net effect is little change of overall PVR to hypoxia with time. Normoxic control animals had little change in their hemodynamics and the large majority of the lung pieces did not change their resistance over 3h. We speculate that the differential response of regions may be due to a differential role of nitric oxide, endothelin-1 release or K(+) channels.
Wayne J E Lamm; Blazej Neradilek; Nayak L Polissar; Michael P Hlastala
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Publication Detail:
Type:  Journal Article     Date:  2007-06-13
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  159     ISSN:  1569-9048     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2007 Oct 
Date Detail:
Created Date:  2007-10-01     Completed Date:  2007-12-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  76-84     Citation Subset:  IM    
Department of Medicine, University of Washington, Seattle,WA, USA.
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MeSH Terms
Anoxia / physiopathology*
Lung / blood supply*
Prone Position
Pulmonary Circulation / physiology*
Vascular Resistance / physiology*
Vasoconstriction / physiology*

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