The effect and safety of dexmedetomidine added to ropivacaine in brachial plexus block A meta-analysis of randomized controlled trials

Background: Dexmedetomidine has been used as an adjuvanty added to local anesthetics to prolong analgesia following peripheral nerve blockade. The aim of this meta-analysis was to investigate the effect and safety of dexmedetomidine added to ropivacaine in brachial plexus block (BPB). Methods: A search strategy was created to identify eligible randomized clinical trial (RCT) in PubMed, Embase, and The Cochrane Library (updated May, 2018). The methodologic quality for each included study was evaluated using the Cochrane Tool for Risk of Bias by 2 independent researchers. Results: Twelve RCTs were included in the meta-analysis (n=671). As an adjuvant to ropivacaine, dexmedetomidine significantly reduced the onset time of sensory (mean difference [MD], -3.86 minutes, 95% CI -5.45 to -2.27 minutes; I-2=85%) and motor (MD, -5.21 minutes; 95% CI -7.48 to -2.94 minutes; I-2=94%). In addition, it increased the blockade duration of sensory (MD, 228.70 minutes; 95% CI 187.87-269.52 minutes; I-2=93%) and motor (MD, 191.70 minutes; 95% CI 152.48-230.91 minutes; I-2=92%). Moreover, the combination prolonged the duration of analgesia (MD, 303.04 minutes; 95% CI 228.84-377.24 minutes; I-2=86%). There was no difference of the incidence of bradycardia (risk difference [RD], 0.01, 95% CI -0.02 to 0.05, I-2=45%; P=.45) and hypotension (RD, 0.01, 95% CI -0.01 to 0.03, I-2=0%; P=.57) between 2 groups. Conclusion: Dexmedetomidine added to ropivacaine in BPB has a better analgesia effect (shorter onset time and longer duration) compared to ropivacaine alone. At the same time, there was no difference in the incidence of bradycardia and hypotension.