Document Detail

Microvascular volume changes induced by exercise, heat exposure, or endotoxin injection.
MedLine Citation:
PMID:  8092279     Owner:  NLM     Status:  MEDLINE    
The microcirculation as a blood reservoir for volume compensation and the microvascular volume change (MVC) as a means of blood volume regulation are investigated. The density equations of LaForte et al. [Am. J. Physiol. 262 (Heart Circ. Physiol. 31): H190-H199, 1992] are modified to assess the MVC and volume of fluid restitution from changes in systemic hematocrit and plasma protein concentration induced by maximal exercise. It is estimated that exercise causes an MVC that is 5.6% of total blood volume (Vb) to counter the effect of plasma volume loss at 9.4% of Vb. A similar analysis of the result for 120 min of heat exposure indicates that the plasma volume decreases by 8.1% of Vb while the microcirculation constricts to produce an MVC that is 7.9% of Vb, with a net result of insignificant change in the macrovascular volume. Analysis of endotoxin injection to splenectomized dogs indicates that the microvascular dilation and plasma volume decrease combine to decrease the macrovascular volume by 31%, which may lead to the endotoxin shock. I conclude from these findings and the results of lower body negative pressure suction and cyclic hemorrhage that MVC could alter macrovascular filling to change cardiovascular function. It is also shown that the use of systemic hematocrit change as the sole determinant of plasma volume change could be erroneous.
J S Lee
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  267     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1994 Sep 
Date Detail:
Created Date:  1994-10-19     Completed Date:  1994-10-19     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H1142-50     Citation Subset:  IM    
Department of Biomedical Engineering, University of Virginia, Charlottesville 22908.
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MeSH Terms
Blood Volume* / drug effects
Endotoxins / pharmacology*
Hot Temperature*
Microcirculation / drug effects
Models, Cardiovascular
Physical Exertion*
Grant Support
Reg. No./Substance:

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