Vein occlusion by upper versus forearm tourniquets in humans.

Study Objective: To determine the optimal location for a tourniquet applied to the arm during cannulation of a hand vein.

Design: Experimental study.

Setting: Operating room of a university hospital.

Subjects: 15 volunteers, 6 men and 9 women.

Measurements: A vein on the dorsum of the hand was cannulated and attached to a pressure transducer. A blood pressure cuff was applied to the forearm or upper arm and inflated in graded steps. Vein pressure was recorded when it became steady. Studies were carried out in random order with the cuff on both the forearm and upper arm of both arms of each subject.

Main Results: Vein pressure averaged 70% to 80% of cuff pressure and was higher when the cuff was located on the forearm at cuff pressures of 20 to 40 mmHg. Time to reach a steady pressure was longer with the cuff on the upper arm (average 109 +/- 58 s) than on the forearm (75 +/- 52 s; P < 0.005).

Conclusions: A tourniquet on the forearm effectively distends hand veins and does so more quickly than a tourniquet on the upper arm.