Temporary arrest of circulation to a limb for the study of venomotor reactions in man.

Abstract

Reflexly mediated venomotor reactions in human limbs can be conveniently measured by following the changes in venous pressure distal to a pneumatic cuff inflated to arrest the circulation to the part. About 2 min after the arrest, the venous pressure becomes stable. Subsequent changes in venous pressure are due to active changes in tension in the vein walls and are independent of changes in caliber of the precapillary vessels. The metabolic changes associated with arrest of the circulation do not alter the venomotor reactions. With temporary arrest of the circulation for 10-min periods, with 5 min for recovery, recordings can be continued for hours. The reactions of hand, foot, forearm, and calf veins can be studied separately or simultaneously. In response to the stimulus of a deep breath, the increase in venous pressure was greatest in hand and foot veins, intermediate in forearm veins, and least in the long saphenous vein.