The Analgesic Efficacy of Dexmedetomidine as an Adjunct to Local Anesthetics in Supraclavicular Brachial Plexus Block

Abstract

This study was designed to assess the effects of dexmedetomidine on the onset and duration of block and postoperative analgesia during supraclavicular brachial plexus block in patients undergoing upper limb surgeries.Sixty adult patients undergoing upper limb and hand surgeries were randomly allocated into 2 groups. The control group received equal volumes of 0.75% ropivacaine and 2% lidocaine with adrenaline, whereas the dexmedetomidine (dexmed) group received 1 μg/kg dexmedetomidine along with equal volumes of 0.75% ropivacaine and 2% lidocaine with adrenaline. A total volume of 0.5 mL/kg was administered in ultrasound-guided supraclavicular brachial plexus block in both groups. Patients were observed for hemodynamic stability, onset and duration of sensory and motor blockade, duration of analgesia, postoperative pain, and adverse effects.The onset time of motor blockade was shortened and the duration of sensory, as well as motor, block was significantly prolonged in the dexmed group (P < 0.0001). The duration of postoperative analgesia was also longer in the dexmed group compared with the control group (median [interquartile range], 12 [10.5-13.5] hours and 17 [10.5-19.5] hours in control and dexmed group, respectively [95% confidence interval, -5 {-5, -4}, P < 0.0001]). The requirement for rescue analgesic during the 24-hour postoperative period was less in the dexmed group (P < 0.0001). Postoperative pain scores were comparable among groups except at 8 and 10 hours, when pain scores were lower in the dexmed group. Patients receiving dexmedetomidine were more sedated for 2 hours than the control group patients (P < 0.0001). No episode of bradycardia, hypotension, respiratory depression, or dizziness was reported.We conclude that the addition of dexmedetomidine to ropivacaine-lidocaine prolonged the duration of supraclavicular brachial plexus block and improved postoperative analgesia without significant adverse effects in patients undergoing upper limb surgeries.