Analgesic effect of Ropivacaine combined with Dexmedetomidine on brachial plexus block

BACKGROUND: This randomized controlled study investigated the analgesic effect of ropivacaine in combination with dexmedetomidine versus ropivacaine alone on brachial plexus block to provide alternative anesthetic means for upper limb trauma surgery. METHODS: Totally 114 patients who received upper limb surgeries under brachial plexus block anesthesia in our hospital from February 2013 to July 2015 were enrolled. The patients were randomized to ropivacaine alone (the control group) or ropivacaine combined with dexmedetomidine (the combination group). The blocking effect on sensory and motor neurons, visual analog scale (VAS) score, heart rate (HR), mean arterial pressure (MAP), peripheral capillary oxygen saturation (SPO(2)) and adverse reactions were compared between the two groups. RESULTS: The time to onset of sensory and motor nerve blockade was significantly shorter in the combination group than in the control group (8.9 min vs. 12.4 min for sensation blockade; 7.5 min vs. 12.8 min for motor blockade, P < 0.05 for both comparisons), and the duration of the blockade was significantly longer in the combination group (590.2 min vs. 532.1 min, P < 0.05). There was no significant difference in VAS scores between the two groups immediately and 4 h after surgery; however, 8, 12 and 24 h after surgery, the VAS scores were all significantly lower in the combination group than the control group (2.4 vs. 3.0 for 8 h; 2.2 vs. 4.2 for 12 h, and 2.1 vs. 5.4 for 24 h, respectively, P < 0.05 for all comparisons). There was no statistical difference in HR, MAP and SPO(2) between the two groups before anesthesia, but after anesthesia, the MAP and HR were significantly lower, and the SPO(2) was significantly higher in the combination group than the control group (78 vs. 84 for MAP; 72 vs. 79 for HR; and 95.1 vs. 88.2 for SPO(2), P < 0.05 for all comparisons). The rates of adverse reaction was significantly lower in the combination group than the control group (3.6 vs. 7.2, P < 0.05). CONCLUSION: The brachial plexus blocking effect of ropivacaine combined with dexmedetomidine was superior to that of ropivacaine alone, mainly intra-operatively and postoperatively. TRIAL REGISTRATION: Analgesic Effect of Ropivacaine Combined with Dexmedetomidine on Brachial Plexus Block, ChiCTR1800017372, retrospectively registered on July 26, 2018.