Identifier

etd-04152004-134854

Degree

Master of Science (MS)

Department

Kinesiology

Document Type

Thesis

Abstract

Recent work by Tschakovsky & Hughson (Am J Physiol Heart Circ Physiol 279: H1007, 2000) indicates that venous emptying serves as a stimulus for vasodilation. This suggests the importance of recognizing the potential influence of venous volume on reactive hyperemic blood flow (RHBF) following occlusion. Purpose: To examine the influence of venous emptying on RHBF. Methods: Non-dominant forearm in-flow, venous capacitance and outflow were examined in 21 individuals [age=23±2.27y]. Forearm arterial inflow, venous capacitance, and outflow were obtained two times using strain gauge plethysmography. Forearm blood inflow was estimated at rest and following 5 min of upper arm occlusion. Forearm venous capacitance and outflow were obtained following 5 min of upper arm venous occlusion pressure at 7 mmHg below diastolic blood pressure. Prior to the second measure the arm was passively elevated for 2 minutes. Immediately before returning the arm to its original position the upper arm cuff was again inflated to 240mmHg. Subsequently, RHBF and venous measures were obtained. Results: Average resting in-flow was 2.84±1.22 ml/100ml/min. RHBF was significantly greater following venous emptying (Before: 18.15±3.80; After: 23.70±5.93 ml/100ml/min, p=0.0001). Venous capacitance was also greater (Before: 1.96±0.82; After: 2.94±0.82 %, p=0.0001), whereas venous outflow (Before: 37.06±10.50; After: 39.00±10.72 ml/100ml/min, p=0.17) remained unaffected after venous emptying. Summary: Venous emptying prior to upper arm occlusion results in a significant greater RHBF response and venous capacitance. A potential explanation for the observation is a decrease in the pressure gradient across the tissue bed and/or withdrawal of the venoarteriolar reflex constriction.

Date

2004

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Michael Welsch

Included in

Kinesiology Commons

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