Brief reports: nerve stimulator evoked motor response predicting a successful supraclavicular brachial plexus block.

ABSTRACT

BACKGROUND: We examined the success rate of supraclavicular brachial plexus block after the different evoked motor responses to nerve stimulation. METHODS: This multicenter observational study included 377 patients. For each block, the evoked motor response elicited at 0.25 mA for 2 milliseconds was recorded, 30 mL bupivacaine 0.25% was injected, and the block was observed for success or failure. RESULTS: Complete anesthesia occurred in 317 cases (84.1%). The success rate was 100% when the evoked motor response was simultaneous flexion of the third and fourth digits or flexion of all 4 digits (digits 2-5) with or without thumb opposition. CONCLUSION: Simultaneous flexion of the third and fourth digits with or without other digits is associated with the highest success rate of supraclavicular brachial plexus block.