Document Detail


Leg intravenous pressure during head-up tilt.
MedLine Citation:
PMID:  18635882     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Leg vascular resistance is calculated as the arterial-venous pressure gradient divided by blood flow. During orthostatic challenges it is assumed that the hydrostatic pressure contributes equally to leg arterial, as well as to leg venous pressure. Because of venous valves, one may question whether, during orthostatic challenges, a continuous hydrostatic column is formed and if leg venous pressure is equal to the hydrostatic pressure. The purpose of this study was, therefore, to measure intravenous pressure in the great saphenous vein of 12 healthy individuals during 30 degrees and 70 degrees head-up tilt and compare this with the calculated hydrostatic pressure. The height difference between the heart and the right medial malleolus level represented the hydrostatic column. The results demonstrate that there were no differences between the measured intravenous pressure and the calculated hydrostatic pressure during 30 degrees (47.2 +/- 1.0 and 46.9 +/- 1.5 mmHg, respectively) and 70 degrees head-up tilt (83.9 +/- 0.9 and 85.1 +/- 1.2 mmHg, respectively). Steady-state levels of intravenous pressure were reached after 95 +/- 12 s during 30 degrees and 161 +/- 15 s during 70 degrees head-up tilt. In conclusion, the measured leg venous pressure is similar to the calculated hydrostatic pressure during orthostatic challenges. Therefore, the assumption that hydrostatic pressure contributes equally to leg arterial as well as to leg venous pressure during orthostatic challenges can be made.
Authors:
Jan T Groothuis; Fleur Poelkens; Constantijn W Wouters; Miriam Kooijman; Maria T E Hopman
Publication Detail:
Type:  Comparative Study; Journal Article     Date:  2008-07-17
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  105     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2008 Sep 
Date Detail:
Created Date:  2008-09-09     Completed Date:  2008-10-03     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  811-5     Citation Subset:  IM    
Affiliation:
Radboud Univ. Nijmegen Medical Centre, Dept. of Physiology, Geert Grooteplein-noord 21, 6525 EZ Nijmegen, The Netherlands.
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MeSH Terms
Descriptor/Qualifier:
Adult
Dizziness / physiopathology*
Female
Humans
Hydrostatic Pressure
Leg / blood supply*
Male
Models, Cardiovascular
Posture*
Saphenous Vein / physiopathology*
Tilt-Table Test
Time Factors
Vascular Resistance
Venous Pressure*

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


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