A comparative study between the effect of verapamil versus nalbuphine as an adjuvant in supraclavicular brachial plexus block

Background
Brachial plexus block has substituted general anesthesia in the majority of patients planned for upper limb surgeries as it avoids the undesired effects of the medications used in general anesthesia as well as the stress response associated with airway manipulation. Opioid agonist–antagonists such as nalbuphine are used as adjuvant to improve the anesthetic properties of bupivacaine. Verapamil has an additive effect in brachial plexus blockade in the form of decreasing the consumption of analgesics in the postoperative period with reducing onset time and extending the duration of motor and sensory blockade. The aim of this study is to investigate the adjuvant effect of verapamil versus nalbuphine to 0.5% bupivacaine in brachial plexus block as regards onset, duration of sensory and motor blockade and postoperative analgesic augmentation. The study is randomized, prospective, double-blinded, comparative study where 90 patients subjected to arm, forearm and hand surgeries were randomized into three groups, group A received 30 ml of plain bupivacaine 0.5% plus 2 ml of normal saline, group B received 30 ml of bupivacaine 0.5% plus 2 ml verapamil equivalent to 5 mg, group C received 30 ml of bupivacaine 0.5% plus 10 mg of nalbuphine diluted in 2 ml of normal saline.
Results
Results of this study showed that group C and group B sensory block time onset was 7.25 ± 1.5 vs. 10.92 ± 3.84 min, < 0.001 and was shorter than that in group A (13.2 ± 2.66 min). In addition, the motor block onset was (11.10 ± 1.24 vs. 13.50 ± 3.77 min, < 0.001) shorter than group A (17.16 ± 1.30 min). In group C and group B, sensory block duration was 396 ± 32.17 vs. 355.83 ± 18.48 min, < 0.001, respectively and was longer than that in group A (321.13 ± 25.08 min). Also, there was prolonged motor block duration in group C and group B recording (338.92 ± 25.2 vs. 302.93 ± 15.24 min, < 0.001) and was longer than that in group A (280.70 ± 32.35 min). Time of demand of rescue analgesia dose was significantly long in group C and group B (449.53 ± 52.45 vs. 418.13 ± 41.12 min, < 0.001) and was longer than group A (361.31 ± 21.42 min). Both verapamil and nalbuphine have additive effect to bupivacaine improving the all anesthetic parameters of the block.
Conclusion
Both drugs produce favorable enhancement of time onset and effective prolongation of duration of sensory and motor blockade and extend the period of postoperative analgesia with superiority to nalbuphine over verapamil.