Effect of altering limb position on blood flow, O₂ uptake, and skin temperature

¹ Department of Physical Medicine and Rehabilitation and Department of Medicine, University of Illinois College of Medicine, Chicago, Illinois

The effect of altering the position of the upper extremity on local blood flow, oxygen uptake and tissue temperatures was studied in a group of 19 normal subjects. In each instance the limb was placed in three positions: 1) horizontally, at the level of the heart; 2) with the elbow at this level, but with the forearm and hand dependent and forming an angle of 34° with the horizontal; and 3) with the forearm and hand elevated and forming an angle of 34° with the horizontal. No consistent change in blood flow or O₂ uptake was noted when the limb was placed in dependency. In the elevated position there was a small, but significant, reduction in blood flow and O₂ uptake. Cutaneous temperature of the forearm was not affected by either position, while a definite fall in skin temperature was noted in the hand in dependency. These results suggest that variations in position of the upper extremity elicit compensatory vascular mechanisms which tend to counteract the hydrostatic effect on local blood flow and O₂ uptake.