Single-cuff Bier's block in the forearm: factors affecting its efficacy and need for supplementation with local anaesthetics.

Bier's block in the forearm is a safe, effective, and reliable method of regional anaesthesia for operations on the upper extremity. We report 155 patients, of whom only 25 had residual sensation after placement of the block, that required additional local anaesthetic. The purpose of this study was to identify the factors responsible for the residual sensation using the single-cuff Bier's block technique. We recorded all those factors that we thought might have an influence. No patients required conversion to a general anaesthetic. The body mass index, the difference of the systolic and tourniquet pressures, and the site of incision were the three factors correlated with the need for additional anaesthesia.