Postoperative analgesia in children using continuous s.c. morphine.

Sixty children (7 months-20 yr; mean 6.5 yr, median 7-8 yr, mode 1-2 yr) undergoing major surgery received a balanced technique of general anaesthesia combined with bupivacaine as a single injection extradural or peripheral nerve block. Postoperative analgesia consisted of a subcutaneous infusion of morphine 1 mg kg-1 body weight in 20 ml of normal saline [corrected] at a rate of 0.3-0.5 ml h-1, controlled by the nursing staff in the surgical ward. Monitoring included SpO2, pain, sedation and nausea/vomiting scores. Infusions were used for a mean of 38.8 h (range 17-80 h). Ninety-seven percent of recordings of SpO2 were greater than 94% and only one recording in 2361 was less than 90%. Ninety-four percent of pain scores indicated either no pain or slight pain; 1% indicated severe pain. On the order of the medical staff, seven children had the rate of infusion of morphine increased to 0.6 ml h-1 [corrected] because of high pain scores. Sedation scores compatible with children being either awake or asleep but rousable by speech alone were recorded on 99.7% of occasions. No child at any time was unrousable. Of 1248 nausea/vomiting scores, only 2.8% indicated the presence of these side effects; in only two children were they thought to be troublesome. As a result of this audit, nursing staff have been permitted to increase the rate of infusion of morphine to 0.6 ml h-1 [corrected] if required.