Low-dose intrathecal morphine for postoperative analgesia in children

BACKGROUND: We evaluated the efficacy and safety profile of low-dose (4-5 mcg/kg) intrathecal morphine for postoperative pain management after various surgical procedures in children. METHODS: We reviewed the pain management service database and the medical records of patients who received low-dose intrathecal morphine for postoperative analgesia at The Children's Hospital of Philadelphia between October 2003 and March 2006. Patients had been prospectively followed for 24-48 h after the intrathecal morphine administration. RESULTS: The medical records of 187 patients were examined. The mean age was 5.6 ± 5.1 yr (median 4.0, interquartile range [IQR] 1.0-10.0). The median maximum pain score during the first 24 h in patients evaluated by the FLACC score and in those evaluated by the numeric verbal rating scale, was 0 (IQR 0-3) and 0 (IQR 0-4), respectively. The mean time to first rescue opioid was 22.4 ± 16.9 h (range: 0-48 h, 95% CI: 19.9-24.8 h). During the first 24 h after surgery, 70 patients (37%) did not receive any opioids (oral or IV). Of the 117 patients who received opioids, 59 (50%) were managed with oxycodone only. Pain was managed with ketorolac in 33% of patients, either alone (11%) or in combination with IV or oral opioids (22%). The incidence of nausea or vomiting, pruritus, and urinary retention was 32%, 37%, and 6% respectively. One patient had transient postdural puncture headache, while two patients received supplemental oxygen beyond the first 60 postoperative minutes to manage occasional episodes of hypoxemia. No severe respiratory depression requiring assisted ventilation or naloxone administration was observed. CONCLUSION: We conclude that low-dose intrathecal morphine in the pediatric population can be a useful and safe adjunct for postoperative analgesia.