A comparative study of caudal bupivacaine and midazolam-bupivacaine mixture for post-operative analgesia in children undergoing genitourinary surgery

Objective: This study was designed to evaluate the analgesic efficacy of ca udal midazolam-bupivacaine combination in providing post-operative pain rel ief in children undergoing genitourinary surgery and to study the occurrenc e of adverse effects. Subjects and methods: Thirty children, aged 2 to 8 ye ars, scheduled for genitourinary surgery were allocated randomly to receive either 0.25% bupivacaine 0.5 ml/kg (group B, n = 15) or 0.25% bupivacaine 0.5 ml/kg with 50 mug/kg midazolam (group BM; n = 15) by the caudal route i mmediately after induction of general anesthesia. Heart rate, arterial bloo d pressure and oxygen saturation were monitored throughout the study period . Postoperative pain was assessed at regular intervals for 12 hours using a n objective pain score. Analgesia was supplemented whenever the pain score was greater than or equal to 4. Duration of analgesia, as well as the requi rement of additional analgesics, were noted. Results: Lowest pain scores we re observed with the addition of midazolam to caudal bupivacaine (p < 0.01) . Duration of analgesia was longer in group BM (11 +/- 0.5 h) as compared t o group B (7.4 +/- 2.1 hours) (p < 0.05). Fewer children (26.6%) required a dditional analgesia in the combination group whereas in group B, 60% of the children received analgesic supplements within 6 hours after surgery (p < 0.05). There were no significant changes in heart rate, blood pressure and oxygen saturation in both groups. We observed no untoward event in either o f the groups. Conclusion: Caudal administration of bupivacaine-midazolam mi xture prolongs post-operative analgesia compared to bupivacaine alone witho ut causing any adverse effects.