The efficacy of simultaneous bilateral axillary brachial plexus block under the guidance of neurostimulator or ultrasound: a prospective study

Purpose This study was designed to investigate the risk of local anesthetic toxicity and efficacy of simultaneous bilateral axillary brachial plexus block performed under the guidance of ultrasound or a neurostimulator. Methods One hundred and twenty patients who were anesthetized with bilateral axillary plexus block simultaneously between February 2012 and March 2014 were enrolled in the study. The patients were anesthetized under the guidance of a neurostimulator (group N, n = 60) or ultrasound (group U, n = 60). The block performance time, procedure-related pain, adverse events, total and free plasma concentrations of ropivacaine, and other data were recorded. The comparison was analyzed statistically. Results The block performance time, and onset of the sensory and motor block, of group N was longer than that of group U ( p < 0.001). The procedure-related pain of group N was more serious than that of group U ( p < 0.05). The patient satisfaction rate of group U was higher than that of group N ( p < 0.05). The total plasma concentrations of ropivacaine in group N were comparable to those of group U, except for the value at 50 min after injection ( p < 0.05). The free plasma concentrations of ropivacaine of group N at 5 min were significantly higher than that of group U ( p < 0.001). No apparent serious adverse events were observed perioperatively in both groups. Conclusions Simultaneous bilateral axillary brachial plexus block guided by neurostimulator or ultrasound in bilateral distal upper extremity surgery seems to have a low risk of local anesthetic toxicity and to be effective. The ultrasound-guided block is superior in terms of providing the same degree of anesthesia with shorter duration, less pain, and faster onset of sensory and motor blockades, which is important in clinical practice.