Document Detail


Orthostatic hypotension and the role of changes in venous capacitance.
MedLine Citation:
PMID:  8897400     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We suggest a mechanism by which blood volume changes might explain the hypotension that, after space flight, often accompanies the return to normal gravity. Upon entering microgravity, peripheral veins may collapse and, because of volume redistribution, raise the pressure in the central venous compartment. After some time in space, homeostatic mechanisms may cause volume excretion and reduce the pressure in the central venous compartment to normal values. Upon return to normal gravity, peripheral veins may re-expand and distribute a reduced blood volume into an enlarged space, thus lowering pressure in the central venous compartment. This would reduce cardiac preload, output, and arterial pressure. To prevent this sequence of events, leg cuffs might be inflated before the end of the space flight to allow homeostatic mechanisms to increase blood volume to normal levels.
Authors:
J V Tyberg; D R Hamilton
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  28     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  1996 Oct 
Date Detail:
Created Date:  1997-03-19     Completed Date:  1997-03-19     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  S29-31     Citation Subset:  IM; S    
Affiliation:
Department of Medicine, University of Calgary, Alberta, Canada. jtyberg@cvr.ucalgary.ca
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MeSH Terms
Descriptor/Qualifier:
Blood Circulation
Blood Volume
Humans
Hypotension, Orthostatic / physiopathology*
Leg / blood supply
Space Flight*
Vascular Capacitance*
Veins / physiology
Weightlessness*

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


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