Document Detail

Pressure and flow changes in the pulmonary circulation in exercising sheep: evidence for elevated microvascular pressure.
MedLine Citation:
PMID:  8466128     Owner:  NLM     Status:  MEDLINE    
The purpose of this study was to measure hemodynamic and transvascular filtration changes in the lung during strenuous exercise in sheep. The specific goals were (1) to determine the nature of the reduction in pulmonary arterial pressure (Ppa) after its initial peak rise with onset of exercise; (2) to use a pulmonary artery catheter distal wedge technique ("microwedge") to better assess longitudinal changes in resistance in the pulmonary circulation with exercise; and (3) to compare lung lymph flow and protein concentration changes at comparable estimated microvascular pressure (Pmv) (mean Ppa - mean left atrial pressure) (Pla) x 0.4 + mean Pla) during exercise versus passive left atrial hypertension to determine whether exercise causes a higher than expected lymph flow. We found that cardiac output rises quickly and thereafter remains constant with constant-rate exercise, and, thus, the secondary reduction in Ppa was due to vasodilation and/or recruitment. The microwedge pressure rose more than did Pla, suggesting that actual Pmv was probably higher than that estimated. With hypoxia, most of the change in pulmonary vascular resistance was in upstream vessels (arteries and capillaries), as was most of the exercise-induced vasodilation. Lymph flow rose more quickly and was much higher during brief exercise than during left atrial hypertension at a comparable calculated Pmv, and lymph protein content decreased more quickly. The data point to a Pmv with strenuous exercise that is higher than expected.
J H Newman; C P Cochran; R J Roselli; R E Parker; L S King
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American review of respiratory disease     Volume:  147     ISSN:  0003-0805     ISO Abbreviation:  Am. Rev. Respir. Dis.     Publication Date:  1993 Apr 
Date Detail:
Created Date:  1993-04-30     Completed Date:  1993-04-30     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370523     Medline TA:  Am Rev Respir Dis     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  921-6     Citation Subset:  AIM; IM; S    
Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee.
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MeSH Terms
Anoxia / physiopathology
Atrial Function
Blood Pressure*
Cardiac Output
Lymph / physiology
Microcirculation / physiology
Physical Exertion*
Pulmonary Artery / physiology
Pulmonary Circulation / physiology*
Pulmonary Wedge Pressure
Vascular Resistance
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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