A randomized trial comparing axillary block versus targeted intracluster injection supraclavicular block for upper...

This randomized trial aimed to validate a new method for brachial plexus blockade, i.e., targeted intracluster injection supraclavicular block (TII SCB), by comparing it with ultrasound-guided axillary block (AXB). We hypothesized that TII SCB would result in a shorter total anesthesia-related time.

Forty patients undergoing upper limb surgery were randomized to ultrasound-guided TII SCB (n = 20) or AXB (n = 20). In the TII SCB group, we deposited 16 mL of lidocaine 1.5% with epinephrine 5 µg·mL(-1) into the largest neural cluster (i.e., brachial plexus trunks/divisions). Subsequently, an additional 16 mL was divided into equal aliquots and injected inside each satellite cluster. In the AXB group, 5.5 mL were deposited around the musculocutaneous nerve and 23.5 mL were injected at the 6 o'clock position of the axillary artery. The main outcome for comparison between the two groups was the total anesthesia-related time (defined as the sum of block performance and onset times). We also recorded the number of needle passes, procedural pain, and complications (vascular puncture, paresthesia).

The TII SCB method provided a quicker mean (SD) onset time compared with the AXB group [9.5 (5.8) min vs 18.9 (6.1) min; mean difference, -9.5 min; 99% CI, -14.7 to -4.2; P < 0.001] and a shorter mean (SD) total anesthesia-related time [20.1 (5.0) min vs 27.2 (6.5) min; mean difference, -7.0 min; 95% CI, -10.9 to -3.1; P = 0.001]. There were no intergroup differences in terms of success rate (95%), procedural pain, vascular puncture and paresthesia. The AXB group displayed a faster performance time [8.2 (1.6) min vs 10.6 (2.6) min; P = 0.001] with fewer median [interquartile range] needle passes (3 [2-6] vs 5 [4-8]; P < 0.001).

Ultrasound-guided TII SCB provides a quicker onset and a shorter total anesthesia-related time than ultrasound-guided AXB.