Influence of venous emptying on the reactive hyperemic blood flow response.
BACKGROUND
Previous research indicates that venous emptying serves as a stimulus for vasodilation in the human forearm. This suggests the importance of recognizing the potential influence of venous volume on reactive hyperemic blood flow (RHBF) following occlusion. The purpose of this study was to examine the influence of venous emptying on forearm vascular function.


METHODS
Forearm RHBF, venous capacitance and venous outflow were examined in 35 individuals (age = 22 +/- 2 years), using mercury in-Silastic strain gauge plethysmography, at rest and following five minutes of upper arm occlusion using standard procedures (CONTROL). In addition, the same measures were obtained following five minutes of upper arm occlusion preceded by two minutes of passive arm elevation (Pre-elevation).


RESULTS
Average resting arterial inflow was 2.42 +/- 1.11 ml x 100 ml(-1) x min(-1). RHBF and venous capacitance were significantly greater during Pre-elevation compared to CONTROL (RHBF; Pre-elevation: 23.76 +/- 5.95 ml x 100 ml(-1) x min(-1) vs.


METHODS
19.33 +/- 4.50; p = 0.001), (venous capacitance; Pre-elevation: 2.74 +/- 0.89 % vs.


METHODS
2.19 +/- 0.97, p = 0.001). Venous outflow did not differ between the two conditions.


CONCLUSIONS
Venous emptying prior to upper arm occlusion results in a significant greater RHBF response and venous capacitance. Recognition of the influence of venous volume on RHBF is particularly important in studies focusing on arterial inflow, and also provides further evidence for the interplay between the venous and arterial system.
Bahadir
Zeki
Z
Department of Kinesiology, Louisiana State University, Baton Rouge, LA, USA. bahadirz@mybr.cc
Tisdell
Eric
E
Arce Esquivel
Arturo A
AA
Dobrosielski
Devon A
DA
Welsch
Michael A
MA