Comparison Between Intrathecal Neostigmine and Fentanyl as Adjuvant to Hyperbaric Bupivacaine in Spinal Anaesthesia for Post-Operative Pain Relief

Abstract

Objective: Many adjuvants are used during lumbar spinal anaesthesia for lower limb and abdominal surgeries in day-to-day anaesthesia practice. The objectives of the study are to evaluate the time to onset of sensory and motor block, analgesic effect, and side effects of Neostigmine and Fentanyl as an adjuvant to hyperbaric Bupivacaine in spinal anaesthesia. Methods: 80 patients aged 18 to 60 y of either sex, American Society of Anaesthesiologist (ASA) Physical Status I and II, undergoing elective lower limb and abdominal surgeries under lumbar spinal anaesthesia, were randomly divided into two groups-Group N and Group F, with 40 patients each. Group N received 50 µg Neostigmine and Group F received 30 µg Fentanyl with 03 ml of 0.5% hyperbaric Bupivacaine intrathecally. Intraoperative vitals, onset of sensory and motor block, time to first rescue analgesia, and side effects were recorded. Results: There was no significant difference in the time to the onset of sensory block, peak sensory block (T6) and motor block in both groups (p-value>0.05). However, the two-segment block regression was slower, and the time to rescue analgesia was delayed in Group N than in Group F (p-value<0.0001). Except for nausea and vomiting, other side effects like hypotension, bradycardia, etc., were not significant and managed successfully. Conclusion: Both Neostigmine and Fentanyl are safe and effective adjuvant to hyperbaric Bupivacaine in spinal anaesthesia for post-operative analgesic effect. However, due to the higher incidence of nausea and vomiting, the use of Neostigmine as an adjuvant is limited.