Postincision wound infiltration with bupivacaine versus pethidine for postoperative pain relief following myomectomy under spinal anesthesia

Context: Bupivacaine is commonly used agent for wound infiltration because of its local anesthetic effect. However, pethidine an opioid has both local anesthetic and systemic analgesic effect. The combined analgesic effect of pethidine may be superior to bupivacaine that has only a local anesthetic effect. Few studies have however supported the superiority of pethidine over bupivacaine for wound infiltration. Aims: The aim of this study is to evaluate the analgesic effect of pethidine in comparison with bupivacaine wound infiltration for postoperative pain control in nonparturients scheduled for myomectomy under spinal anesthesia. Setting and Design: This study is a prospective, randomized, double-blinded control trial of the analgesic efficacy of plain bupivacaine versus pethidine for patients scheduled for myomectomy under spinal anesthesia in a Tertiary Healthcare center in Nigeria. Subjects and Methods: Seventy-six American Society of Anesthesiologists 1 and 11 patients billed for myomectomy using spinal anesthesia were randomized into two groups. Group bupivacaine had wound infiltration with 50 mg isobaric bupivacaine at a concentration of 0.25%. Group pethidine had 1 mg/kg pethidine. In the ward, pain was assessed at various intervals at rest and on coughing using the numerical rating scale (NRS) pain assessment tool and the time of the first analgesic request. Statistical Analysis: NRS scores were presented as median with interquartile range, Continuous variables such as duration of analgesia and total analgesic consumption were analyzed using the unpaired Student's t-test. Results: The pethidine group had a longer time to first analgesic request, lower pain scores and a higher level of satisfaction. Conclusion: This study showed that postincision wound infiltration with pethidine at 1 mg/kg as a component in multimodal analgesia is more effective than 0.25% bupivacaine in the management of postmyomectomy pain.