Pain relief for infants undergoing abdominal surgery: comparison of infusions of i.v. morphine and extradural bupivacaine.

We have undertaken a prospective, randomized double-blind study to compare extradural bupivacaine infusions with i.v. morphine infusions for postoperative analgesia in 32 infants younger than 4 yr undergoing abdominal surgery. "Sham" extradural or i.v. catheters were used to maintain the blinded nature of the study. Both techniques provided adequate analgesia for most of the 36-h postoperative period; differences in the pattern or quality of the analgesia were not detected. Patients in the i.v. morphine group were significantly more sedated; this was accompanied by slower ventilatory frequencies (26.7 (SD 1.8) b.p.m.) compared with the extradural group (33.6 (1.3) b.p.m.). Similarly, oxygen saturation was significantly less (P < 0.01) in patients receiving morphine (medians and quartiles of 94.0 (93-96)% compared with 96.0 (93-96)%). Mean systolic arterial pressure was similar in the two groups and there were no life-threatening complications. The lack of sedation was troublesome in three patients in the extradural group.