Randomized prospective study of three different techniques for ultrasound-guided axillary brachial plexus block

Introduction: Randomized prospective study comparing two perivascular techniques with the perineural technique for ultrasound-guided axillary brachial plexus block (US-ABPB). The primary objective was to verify if these perivascular techniques are noninferior to the perineural technique. Method: 240 patients were randomized to receive the techniques: below the artery (BA), around the artery (AA) or perineural (PN). The anesthetic volume used was 40 mL of 0.375% bupivacaine. All patients received a musculocutaneous nerve blockade with 10 mL. In BA technique, 30 mL were injected below the axillary artery. In AA technique, 7.5 mL were injected at 4 points around the artery. In PN technique, the median, ulnar, and radial nerves were anesthetized with 10 mL per nerve. Results: Confidence interval analysis showed that the perivascular techniques studied were not inferior to the perineural technique. The time to perform the blockade was shorter for the BA technique (300.4 +/- 78.4 s, 396.5 +/- 117.1 s, 487.6 +/- 172.6 s, respectively). The PN technique showed a lower latency time (PN - 655.3 +/- 348.9 s; BA - 1044 +/- 389.5 s; AA -932.9 +/- 314.5 s), and less total time for the procedure (PN - 1132 +/- 395.8 s; BA - 1346.2 +/- 413.4 s; AA -1329.5 +/- 344.4 s). BA technique had a higher incidence of vascular puncture (BA -22.5%; AA -16.3%; PN - 5%). Conclusion: The perivascular techniques are viable alternatives to perineural technique for US-ABPB. There is a higher incidence of vascular puncture associated with the BA technique. (C) 2017 Published by Elsevier Editora Ltda. on behalf of Sociedade Brasileira de Anestesiologia.