Increased distensibility in dependent veins following prolonged bedrest
2009 (English)In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 106, no 4, 547-554 p.Article in journal (Refereed) Published
Displacement of blood to the lower portion of the body that follows a postural transition from recumbent to erect is augmented by a prolonged period of recumbency (bedrest). Information is scarce as to what extent this augmented blood-volume shift to dependent veins is attributable to increased distensibility of the veins. Accordingly, we studied the effect of 5 weeks of horizontal bedrest on the pressure-distension relationship in limb veins. Elevation of venous distending pressure was induced by exposure of the body except the tested limb to supra-atmospheric pressure with the subject seated in a pressure chamber with one arm, or supine with a lower leg, protruding through a hole in the chamber door. Diameter changes in response to an increase of intravenous pressure (distensibility) from 60 to about 140 mmHg were measured in the brachial and posterior tibial veins using ultrasonographic techniques. Prior to bedrest, the distensibility was substantially less in the tibial than in the brachial vein. Bedrest increased (P < 0.01) pressure distension in the tibial vein by 86% from 7 +/- A 3% before to 13 +/- A 3% after bedrest. In the brachial vein, bedrest increased (P < 0.05) pressure distension by 36% from 14 +/- A 5% before to 19 +/- A 5% after bedrest. Thus, removal of the gravity-dependent pressure components that act along the blood vessels in erect posture increases the distensibility of dependent veins.
Place, publisher, year, edition, pages
2009. Vol. 106, no 4, 547-554 p.
Sustained bedrest, Venous compliance, Gravity, Blood-volume distribution, Vascular deconditioning
IdentifiersURN: urn:nbn:se:kth:diva-25954DOI: 10.1007/s00421-009-1044-3ISI: 000266814800008PubMedID: 19347352OAI: oai:DiVA.org:kth-25954DiVA: diva2:361112
QC 201011082010-11-082010-11-082010-11-09Bibliographically approved