Nalbuphine for spinal anesthesia: A systematic review and meta-analysis

Various adjuvants for prolongation of intra-operative and postoperative analgesia have been clinically studied, but the safety and efficiency of nalbuphine as an adjuvant to local anesthetics in spinal anesthesia remains unconfirmed. Therefore, we conducted a meta-analysis about the effect of nalbuphine as an adjuvant to local anesthetics in spinal anesthesia in regard to time of onset of sensory blockade and motor blockade, duration of motor blockade, 2-segment sensory regression time, the duration of analgesia, and incidence of side effects to provide a reliable basis for clinical application.

Databases, including PubMed, Cochrane, EMBASE, Web of Science, CNKI, CBM, WanFang, and Viper, were searched for eligible studies. Data were extracted according to the proposed inclusion and exclusion criteria, RevMan version 5.3 and Stata 16 were selected to perform meta-analysis.

Eighteen published studies including 1633 patients met the inclusion criteria. The results showed that adding nalbuphine to local anesthetics for spinal anesthesia can prolong two-segment sensory regression time (mean difference [MD] = 24.31; 95% confidence interval [CI] = 19.61-29.00, p < 0.001) and the duration of analgesia (MD = 118.11; 95% CI = 71.34-164.89, p < 0.001) without significantly increasing the incidence of adverse reactions in comparison to normal saline group. In addition, the analgesic effect of nalbuphine group was not statistically different from that of control group when compared with the potent opioid group, but the occurrence of hypotension (risk ratio [RR] = 0.35, 95% CI = 0.18-0.68, p < 0.01), the occurrence of shivering (RR = 0.19, 95% CI = 0.08-0.43, p < 0.01), and the occurrence of pruritus (RR = 0.23, 95% CI = 0.10-0.53, p < 0.01) was lower than the potent opioid group.

Nalbuphine as additives to local anesthetics can significantly prolong the two segments of sensory block and the average duration of analgesia without increasing the incidence of adverse reactions when compared with normal saline group. In addition, the analgesic efficacy of nalbuphine served as an adjunct to local anesthetics was clinically not different from that of the potent opioids, but the occurrence of hypotension, shivering, and pruritus was lower than the potent opioids.