Evolution of ultrasound guided axillary brachial plexus blockade: retrospective analysis of 662 blocks

Abstract

Ultrasound (US) is being used increasingly to guide needle placement during axillary brachial plexus blockade (AXB). This retrospective study investigated whether US guidance can increase the success rate, decrease block onset time, and reduce local anesthetic (LA) volume for AXB compared to a traditional (TRAD) approach, namely, peripheral nerve stimulation (PNS) and transarterial (TA) techniques. The anesthetic records, operative reports, discharge summaries, and surgical consultation notes of all patients who had undergone AXB for surgical anesthesia at the Toronto Western Hospital, between October 2003 and November 2006 were, retrospectively reviewed for evidence of block success and associated complications. Block success was defined as the achievement of surgical anesthesia without additional LA supplementation. Among the 662 patients, 535 patients underwent AXB using US guidance (US group), and 127 using TRAD techniques (TRAD group), namely, 56 using PNS (PNS subgroup) and 71 using the TA technique (TA subgroup). The block success rate was higher in the US group compared to the TRAD group (91.6% vs 81.9%, P = 0.003). The LA volume used for AXB was less in the US group compared to the TRAD group (39.8 +/- 6.4 mL vs 46.7 +/- 17.1 mL, P < 0.0001). Ultrasound group patients spent less time in the block procedure room than those in the TRAD group (30.6 +/- 14.2 min vs 40.1 +/- 27.3 min, P < 0.0001). When analyzed by subgroup, the US group demonstrated significantly greater success and shorter duration in the block room compared to the PNS subgroup, but not the TA subgroup. Complications (inadvertent intravenous LA injection, and transient neuropathy) were lower in the US group compared to the TRAD group (0.37% vs 3.15%, P = 0.014). Our results suggest that US-guided AXB may improve block success, reduce the local anesthetic volume used, and shorten the time spent in the block room compared to traditional nerve localization techniques.