Bloqueio do plexo braquial por via axilar com neuroestimulador: verificação da latência e da eficácia

Abstract

Background and Objectives: Axillary brachial plexus block, although widely used due to a low rate of complications, has some drawbacks which limit its use: failure rate, long onset and restrictions to forearm and hand surgery. This study aimed at evaluating onset time and efficacy of axillary brachial plexus block using a nerve stimulator. Methods: Participated in this prospective and open study, 38 patients physical status ASA I, II and III, aged 13 to 74 years, submitted to upper limb surgery. In the operating room, after monitoring, intravenous line and sedation with 1 to 3 mg midazolam, the patients were submitted to axillary brachial plexus block after the use of a nerve stimulator with decreasing currents starting with 0.9 mA and local anesthetic injection after obtaining fingers and hand motor response with the smallest stimulus. Sensory and motor onset, partial or total sensory and motor efficacy as well as failure and side effects were observed. Results: Sensory and motor onset were 5.2 + 3.8 and 4.6 + 3.3 minutes, respectively. There were six partial sensory failures, ten partial motor failures and two total motor failures, while in twenty cases there were no failures. Just two cases needed to be reverted to general anesthesia. Conclusions: We concluded that, in the conditions of our study, the use of nerve stimulator was useful in inducing axillary brachial plexus block, being important to emphasize that in most cases, no more than 0.3 mA was necessary to locate the nerves.