Intrathecal nalbuphine versus fentanyl as an adjuvant to bupivacaine in spinal anesthesia for elective cesarean section: a randomized double-blind study

Abstract

Background Opioids have been used as an adjunct to bupivacaine in spinal blockade to enhance the onset of action, to improve the quality of intraoperative and postoperative analgesia, and to increase the duration of block. Fentanyl is a synthetic opioid agonist and nalbuphine is a synthetic opioid agonist-antagonist. The present study aimed to compare the effects of adding nalbuphine or fentanyl as an adjunct to bupivacaine on the characteristics of spinal blockade, quality of postoperative analgesia, and on fetomaternal outcome after elective cesarean section. Participants and methods A total of 80 full-term parturients scheduled for elective cesarean section were randomly allocated into two groups. Nalbuphine group (BN group) included parturients who received 12.5 mg of 0.5% hyperbaric bupivacaine with 800 μg nalbuphine intrathecally. Fentanyl group (BF group) included parturients who received the same dose of hyperbaric bupivacaine with 25 μg fentanyl intrathecally. Subarachnoid blockade characteristics, duration of postoperative analgesia, the amount of postoperative analgesic requirements, maternal adverse effects, and neonatal outcome were compared. Results Onset of sensory and complete motor block, maximum height of sensory block, and time to two-segment sensory regression were significantly faster in BF group than in BN group. Maximum dermatomal block level was significantly higher in BF group than in BN group. The duration of motor block and the quality of anesthesia of both groups were comparable. Durations of postoperative complete and effective analgesia were highly significantly longer in BN group than the corresponding durations in BF group (P Conclusion As an adjunct to hyperbaric bupivacaine in spinal block, fentanyl was superior to nalbuphine in enhancing the onset of both sensory and motor block. Nalbuphine is superior to fentanyl in increasing the duration of postoperative complete and effective analgesia and in decreasing incidences of pruritus and shivering, and both drugs have similar effects on neonatal APGAR score and neurologic and adaptive capacity score.