Dexmedetomidine versus Nalbuphine as Adjuvant to Low Concentration Bupivacaine in Ultrasound-guided Supraclavicular Brachial Plexus Block: A Randomized Double-blinded Trial

BACKGROUND: This study aimed to compare the adjuvant properties of dexmedetomidine and nalbuphine in ultrasound-guided supraclavicular brachial plexus block using 0.25% bupivacaine in terms of the effects of duration of analgesia achieved, sensorimotor characteristics of block, and postoperative analgesics used. MATERIALS AND METHODS: A total of 60 patients were randomly allocated to receive either 50 μg of dexmedetomidine or 10 mg of nalbuphine in a volume of 30 ml for ultrasound-guided supraclavicular brachial plexus block. The onset time, duration of sensory and motor block, duration of analgesia, need for rescue analgesia, sedation scores, and hemodynamic variables were recorded and compared between the two groups. RESULTS: The onset time was significantly shorter, and the duration of sensory block was significantly longer in the dexmedetomidine group compared to the nalbuphine group. The onset of motor block was faster and of prolonged duration in the dexmedetomidine group. The duration of analgesia was higher in the dexmedetomidine group, with a reduced total dose of rescue analgesics used in the first 24 h postoperatively. Sedation scores and other hemodynamic variables did not differ significantly between the two groups. CONCLUSION: Dexmedetomidine is a more effective adjuvant than nalbuphine in supraclavicular brachial plexus block using low dose 0.25% bupivacaine, as it provided faster onset time, longer sensory and motor block duration, higher duration of analgesia, and reduced need for rescue analgesia. However, both drugs were found to be safe and well-tolerated by patients, with no significant differences in sedation scores or other hemodynamic variables between the two groups. The use of ultrasound guidance for the block placement adds to the precision and safety of the procedure and effectively permits a lower concentration of bupivacaine to be used. Further studies with larger sample sizes are warranted to confirm these findings and explore other aspects of the drug efficacy and safety profiles.