Intrathecal Nalbuphine and Dexmedetomidine as Adjuvants to Bupivacaine versus Plain Bupivacaine for Orthopedic Surgeries under Subarachnoid Block: A Comparative Study.

Background: In long bone surgeries, the severity of pain is more, demanding good intraoperative anesthesia, and prolonged postoperative analgesia. This is achieved in spinal anesthesia with adjuvants to local anesthetics, which act synergistically.

Aims: The aim of this study was to compare the efficacy of nalbuphine and dexmedetomidine as adjuvants to bupivacaine versus bupivacaine alone in lower limb orthopedic surgeries under the subarachnoid block (SAB).

Settings and design: This is a prospective, randomized, double-blind control study conducted on 60 patients belonging to the American Society of Anesthesiologists physical status Classes I and II, undergoing lower limb orthopedic surgeries under SAB.

Materials and methods: Sixty patients were divided into three groups by computer-generated randomization. Group A received 2.7 mL of 0.5% hyperbaric bupivacaine with 1.5 mg nalbuphine, Group B received 2.7 mL of 0.5% hyperbaric bupivacaine with 10 μg dexmedetomidine, and Group C received 2.7 mL of 0.5% hyperbaric bupivacaine with 0.5 mL of normal saline (total volume made to 3.2 mL in all groups with normal saline). Time of onset of block, duration of sensory, and motor blocks were noted. Changes in hemodynamic parameters, postoperative first rescue analgesia requirement, and side effects were recorded.

Statistical analysis used: Data were analyzed using SPSS 22 version software. P < 0.05 was considered statistically significant.

Results: There was no significant difference in the onset of sensory or motor blocks in the three groups. However, the time taken for regression of sensory block was longer in Group B that was statistically significant.

Conclusion: Intrathecal dexmedetomidine acts as a better adjuvant with bupivacaine in providing quality anesthesia, prolonged sensory and motor block, and good postoperative analgesia with less incidence of adverse effects compared to nalbuphine and bupivacaine alone.