Comparison of epidural morphine, hydromorphone and fentanyl for postoperative pain control in children undergoing orthopaedic surgery.

The safety and side-effects profile of epidural administration of a hydrophilic (morphine), highly lipophilic (fentanyl) and a drug with intermediate hydrophilic and lipophilic activity (hydromorphone) were compared in 90 children undergoing orthopaedic procedures. Ninety patients were randomly assigned (30 in each group) to receive epidural morphine, hydromorphone, or fentanyl for postoperative analgesia. Respiratory effects, nausea, somnolence, urinary retention, pruritus and visual pain scales were evaluated and compared during a 30-h period following surgery. In the morphine group, 25% showed respiratory depression with oxygen saturation below 90% but there was no incidence of respiratory depression in the fentanyl or hydromorphone groups. Somnolence was prominent in some of the patients in all the groups, but was more prolonged in the morphine group. Statistically, there was no significant difference in nausea between the groups, but pruritus was more severe and frequent in the morphine group. The incidence of urinary retention in the morphine group was higher compared with the fentanyl and hydromorphone groups. In conclusion, epidural hydromorphone, demonstrating less side-effects, is preferable to morphine and fentanyl for epidural analgesia in children.