Abstract

High venous pressures are postulated as causing leakage under the cuff in intravenous regional anesthesia (IVRA). The influence of preblock exsanguination and rate of injections on the pressures produced in the median cubital vein were investigated in six subjects during sham IVRA with 0.9% saline 50 ml, distal injection. Two rates of injection (50 ml in 1 minute and 50 ml in 2 minutes) and three degrees of exsanguination were used. Peak pressures were highest with fast injection at all degrees of exsanguination ( p < 0.01) and increasing degrees of exsonguination produced successively lower peak pressures at both rates of injection ( p < 0.01). Two of six subjects had venous pressures exceeding a cuff pressure of 250 mm Hg. Pressures attained were poorly related to any measured physical indices such as arm size, body weight, and height. Conditions predisposing to leakage during IVRA may be minimized by efficient preblock exsanguination and slow injections.