Caudal morphine in paediatric patients: a comparison of two different doses in children after major urogenital surgery.

We compared the duration of postoperative analgesia and the occurrence of side-effects of two different doses of caudal morphine in children undergoing major urogenital surgery. Fifty-two children aged between 1 and 12 years were randomly selected to receive caudal morphine, either 25 micrograms.kg-1 (Group A) or 50 micrograms.kg-1 (Group B) with 0.5 ml kg-1 of 0.25% plain bupivacaine immediately before surgery. They were monitored for 24 hours in a high dependency area for known complications of epidural morphine. There was no significant difference in postoperative analgesia between the two doses of caudal morphine. Clinically significant respiratory depression or sedation was not detected in either group. The occurrence of vomiting and pruritus was similar in both groups. Urinary retention was not recorded as all children had an indwelling catheter as required by the surgical procedure. We concluded that 25 micrograms.kg-1 of caudal morphine is as effective as 50 micrograms.kg-1 for providing postoperative analgesia in children undergoing urogenital surgery.