Epidural nalbuphine versus dexmedetomidine as adjuvants to bupivacaine in lower limb orthopedic surgeries for postoperative analgesia: a randomized controlled trial

Abstract Background Administration of adjuvant drugs epidurally in combination with local anesthetics offers new dimensions in the management of postoperative pain. This study aimed to compare the addition of either nalbuphine or dexmedetomidine to epidural bupivacaine for postoperative analgesia in lower limb orthopedic surgeries under combined spinal-epidural anesthesia. Methods This prospective randomized double-blind study included 69 patients scheduled for lower limb orthopedic surgeries. Anesthesia was started with 15 mg hyperbaric bupivacaine 0.5% intrathecally, and then an epidural bolus dose of 12 ml (10 ml 0.25% bupivacaine with 2 ml normal saline in group C, 2 ml (10 mg) nalbuphine in group N or dexmedetomidine 2 ml (100 µg) in group D was administered when sensory regression to T10. Postoperatively, when visual analogue scale (VAS) was ≥ 3, an epidural top-up dose of 8 ml (6 ml 0.25% bupivacaine plus 2 ml normal saline in group C, 2 ml (2 mg) nalbuphine in group N or 20 µg dexmedetomidine (2 ml) in group D was given. The primary outcome was to evaluate the duration of postoperative analgesia and secondary outcomes were any side effects and patient satisfaction. Results The onset of epidural analgesia was 17.83 ± 2.53 versus 13.39 ± 1.27 versus 12.17 ± 1.27 min in groups C, N and D, respectively (p value