Comparison of the efficacy of costoclavicular space brachial plexus blockade with 0.5% versus 0.375% ropivacaine: a randomized, double-blind, single-centre, noninferiority clinical trial

Abstract

Purpose: Recently, more attention has been given to the costoclavicular space (CCS) as an alternative pathway for ultrasound-guided brachial plexus block (BPB). While 0.5% ropivacaine was used in most related studies, research has shown effective ultrasound-guided supraclavicular BPB using lower local anesthetic concentrations, and our preliminary data have indicated that 0.375% ropivacaine may be effective when given in the CCS. Hence, we hypothesized that the efficacy of 0.375% ropivacaine would be noninferior compared with 0.5% in ultrasound-guided BPB via the CCS. Methods: We conducted a randomized, double-blind, single-centre, noninferiority clinical trial. Seventy patients undergoing elective forearm or hand surgery were randomly assigned to receive either 20 mL of 0.375% ropivacaine (experimental group) or 0.5% ropivacaine (control group) in the CCS for BPB. We assessed sensory and motor blockade at five, ten, 15, 20, 25, and 30 min after the injection. The primary outcome was the rate of successful BPB. Secondary outcomes included onset time, duration of sensory and motor blockade, and adverse reactions. The depth from the skin to the CCS was also recorded during the procedure. Results: A total of 69 patients were evaluable for block success. There was one failed block in both groups, yielding a BPB block success rate of 97% in both groups. 0.375% Ropivacaine was noninferior to 0.5% ropivacaine (P = 0.98). There was no significant difference in the median [interquartile range (IQR)] onset time of sensory-motor blockade in the experimental group (15 [15–20] min; N = 34) compared with the control group (15 [13–20] min; N = 33; Mann–Whitney test, P = 0.48). The median [IQR] duration of sensory blockade was significantly shorter in the experimental group (455 [398–490] min vs 610 [570–655] min in the control group; Hodges–Lehmann estimator of the difference, 165 min; 95.08% confidence interval (CI), 130 to 195; P < 0.001). Likewise, the median [IQR] duration of motor blockade was significantly shorter in the experimental group (470 [409–500] min vs 625 [578–665] min in the control group; Hodges–Lehmann estimator of the difference, 165 min; 95.08% CI, 130 to 195; P < 0.001). There were no adverse reactions directly related to the technique or the ropivacaine injection in either group. Conclusions: 0.375% Ropivacainewas noninferior to 0.5% ropivacaine with regard to rate of successful ultrasound-guided costoclavicular BPB. Study registration: chictr.org.cn (ChiCTR20000306570); registered 8 March 2020.