A study to compare the efficacy of intrathecal dexmedetomidine versus nalbuphine as an adjuvant to 0.5% hyperbaric bupivacaine for postoperative analgesia in lower abdominal surgeries

Background: The subarachnoid block is a commonly used technique for lower abdominal surgeries. Bupivacaine being a cost-effective drug gives satisfactory analgesia for 90-120 min. Adjuvants such as dexmedetomidine and nalbuphine extend the analgesia in the postoperative period. In this study, we aimed to compare the effects of intrathecal dexmedetomidine and nalbuphine as an adjuvant to hyperbaric bupivacaine regarding the duration of analgesia as the primary objective and the time of onset of sensory and motor blockade, duration of motor blockade, haemodynamics parameters like mean heart rate and mean arterial blood pressure, and side effects if any being the secondary objectives. Eighty patients, aged 18-65 years of ASA physical status I and II, were randomly allocated into two groups. Group NB (n = 40) received 0.5% Inj. hyperbaric bupivacaine 18 mg (3.6 ml) + Inj.nalbuphine 1.0 mg (0.1 ml) while group DB (n = 40) received 0.5% Inj. hyperbaric bupivacaine 18 mg (3.6 ml) + Inj.dexmedetomidine 10 mu g (0.1 ml). Results: Patients in group DB had a significantly prolonged duration of analgesia as compared to group NB. The early onset of sensory and motor blockade was noted in group DB(P < 0.05). The duration of motor blockade was significantly prolonged in group DB (P < 0.05). Patients in both groups showed no significant difference in haemodynamic changes and incidence of side effects (P > 0.05). Conclusions: Dexmedetomidine as an intrathecal adjuvant was found to have prolonged sensory and motor block and provide good quality of postoperative analgesia and stable haemodynamics with minimal side effects as compared to nalbuphine.