Upper extremity tourniquet tolerance.

Twenty unsedated volunteers were tested to compare the relative tolerance of an arm tourniquet on one side and of a forearm tourniquet on the other. The forearm tourniquet was tolerated an average of 13 minutes (45%) longer and was consistently rated as less painful during and immediately after the test. No subject tolerated the arm tourniquet longer than the forearm tourniquet. Two peaks of discomfort were found, one just before deflation beneath the tourniquet and one in the hand 2 minutes later. Ulnar nerve distribution paresthesias were the earliest changes experienced; however, complete numbness occurred first in the median nerve distribution. Complete paralysis occurred 7 minutes later (24%) with the forearm tourniquet. Pulse rate did not correlate with tourniquet pain, but blood pressure did. No measurable tourniquet-induced edema occurred on either side.