Efficacy of ultrasound-guided axillary brachial plexus block: a comparative study with nerve stimulator-guided method.

BACKGROUND The aim of this study was to compare the efficacy of axillary brachial plexus block using an ultrasound-guided method with the nerve stimulator-guided method. We also compared the efficacy of ultrasound-guided single-injection with those of double-injection for the quality of the block. METHODS Ninety patients scheduled for surgery of the forearm or hand were randomly allocated into three groups (n = 30 per group), i.e., nerve stimulator-guided and double-injection (ND) group, ultrasound-guided and double-injection (UD) group, and ultrasound-guided and single-injection (US) group. Each patient received 0.5 ml kg(-1) of 1.5% lidocaine with 5 mg kg(-1) epinephrine. Patients in the ND group received half the volume of lidocaine injected near the median and radial nerves after identification using a nerve stimulator. Patients in the UD group received half the volume of lidocaine injected around the lateral and medial aspects of the axillary artery, while those in the US group were given the entire volume near the lateral aspect of the axillary artery. The extent of the sensory blockade of the seven nerves and motor blockades of the four nerves were assessed 40 min after the performance of axillary brachial plexus block. RESULTS Seventy percent of the patients in the ND and US groups as well as 73% of the patients in the UD group obtained satisfactory sensory and motor blockades. The success rate of performing the block was 90% in patients in the ND and UD groups and 70% in the US group. The incidence of adverse events was significantly higher in the ND group (20%) compared with that in the US group and the UD group (0%; p = 0.03). CONCLUSIONS Ultrasound-guided axillary brachial plexus block, using either single- or double-injection technique, provided excellent sensory and motor blockades with fewer adverse events.