The effect of dexmedetomidine in coracoid approach brachial plexus block under dual stimulation

Background: Coracoid approach brachial plexus block (CABPB) is safe and effective for clinical anesthesia and analgesia. Dual stimulation can enhance the block effect of CABPB when using nerve stimulator. Dexmedetomidine is a highly selective α-adrenoceptor agonist and it can prolong the duration of anesthesia when it is added into local anesthetics. The aim of this study was to assess the effects of dexmedetomidine on the duration of anesthesia and the effective postoperative analgesia time when it was mixed with ropivacaine for CABPB under dual stimulation. Methods: A total of 60 patients were randomly assigned into 2 groups (groups D and C), 30 patients in each group. CABPB were guided by nerve stimulator under dual stimulation. Each patient received 40 mL of 0.375% ropivacaine (group C), or 40 mL of 0.375% ropivacaine mixed with 1 μg/kg dexmedetomidine (group D). The duration of anesthesia, the effective postoperative analgesia time, sensory and motor block onset time, visual analog scale (VAS), and the cumulative dose of rescue tramadol were recorded. Results: Twenty-eight patients in each group were analyzed. The duration of anesthesia was longer in group D as compared with group C (759 vs 634 minutes, P < .05) and the effective postoperative analgesia time was longer in group D as compared with group C (986 vs 789 minutes, P < .05) too. The onset time of sensory and motor blocks were not significantly different between the 2 groups (P > .05). The VAS was similar in the 2 groups at 6 and 12 hours after block (P > .05), but it was lower in group D at 24 hours after block as compared to group C (P < .05). The cumulative dose of rescue tramadol during the first 48 hours postoperative period was significantly lower in group D as compared to group C (P < .05). No significant changes were observed in vital signs in either group. Conclusion: The addition of 1 μg/kg dexmedetomidine to ropivacaine extends the duration of anesthesia and the effective postoperative analgesia time for CABPB under dual stimulation. The VAS at 24 hours after block and the demand for rescue tramadol during the first 48 hours postoperative period are lower as well without side effects in the study group. (Registered in ClinicalTrials.gov id. NCT02961361).