Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4 Pt 2
pubmed:dateCreated
1991-5-9
pubmed:abstractText
The hemodynamic changes after 24 h of bed rest with -5 degree head-down tilt were studied in six normal subjects as a condition causing an intrathoracic shift of blood volume with a resulting urinary sodium and water loss and a subsequent reduction in total intravascular volume. Vascular resistance and venous tone of the upper and the lower limbs were investigated as were systemic hemodynamics throughout the procedure. Whereas systemic hemodynamic parameters did not change significantly, vascular resistance and venous tone of the upper and lower limbs decreased significantly up to the sixth h and then returned toward baseline values at 24 h. Systemic and forearm vasoconstriction responses to lower body negative pressure (LBNP) were studied just before and at the end of the study period. With LBNP, -5, -10, and -15 mmHg pressure levels were used to investigate mechanoreceptors in the low-pressure system, whereas the -40 mmHg pressure level was used to explore baroreceptors both in low and high pressure systems. Changes in vascular resistance in response to LBNP did not differ at the beginning and at the end of the head-down tilt, whereas an exaggerated heart rate response was observed at -40 mmHg at the end of 24 h of bed rest. The study showed that after 24 h of bed rest with -5 degree head-down tilt, the adaptative changes in venous tone and vascular resistance to blood volume reduction were altered. A dissociation between cardiac and vascular baroreflex response was observed in situations simulating tilting.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
260
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
H1043-50
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Twenty-four hours of bed rest with head-down tilt: venous and arteriolar changes of limbs.
pubmed:affiliation
Department of Internal Medicine, Broussais Hospital, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't