A Comparison of Analgesic Effect of Different Doses of Intrathecal Nalbuphine Hydrochloride with Bupivacaine and Bupivacaine Alone for Infraumblical Surgeries

Background: Subarachnoid block (SAB) possesses many benefits with a drawback of short duration of anesthetic action. Intrathecal opioids have been used to enhance the clinical efficiency and duration of action of local anaesthetic drugs. Nalbuphine is a synthetic opioid with mixed agonist-antagonist action, when added as adjuvant to intrathecal bupivacaine acts on kappa receptors in the dorsal horn of the spinal cord producing analgesia. We compared the analgesic effect of different doses of intrathecal nalbuphine with 0.5 % hyperbaric bupivacaine for infra umblical surgeries. Materials& Methods: 210 ASA class-I and II adult patients of either sex, aged 20-60 years undergoing infraumlical surgeries under spinal anaesthesia were selected and randomly allocated in 3 groups (n=70) in a randomized, double-blinded manner. Group A received 3 mL of 0.5 % heavy bupivacaine 15 mg + 0.5 mL of 0.9 % normal saline to a total volume of 3.5 mL. Group B received 3 mL of 0.5 % heavy bupivacaine 15 mg + 0.5 mL of 0.8 mg nalbuphine with 0.9 % normal saline to a total volume of 3.5 mL. Group C received 3 mL of 0.5 % heavy bupivacaine 15 mg + 0.5 mL of 2.5 mg nalbuphine with 0.9 % normal saline to a total volume of 3.5 mL. We assessed the duration of analgesia following administration of spinal anaesthesia. Observation: There was no difference between the groups with regard to demographic data, duration of surgery, highest sensory and motor level achieved. The mean total analgesia time in subjects of group C (264.56 min) was highest, while subjects of group A had 123.01 min and group B had 185.19 min duration of analgesia. This difference in mean total analgesia time among the three study groups was statistically significant. (p