Does patient-controlled analgesia achieve better control of pain and fewer adverse effects than intramuscular analgesia? A prospective randomized trial.

OBJECTIVE: To compare three analgesic regimens in patients undergoing colon resection: patient-controlled morphine sulfate analgesia (PCA), intramuscular (IM) morphine, and IM ketorolac tromethamine.

DESIGN: Prospective randomized case series.

SETTING: Rural, private teaching hospital.

PATIENTS: All patients (307) scheduled to undergo a major colon resection between January 1, 1992, and December 31, 1993, were eligible to participate. Of these, 10 (3%) were missed in the screening process, 132 (43%) declined participation, 73 (24%) were excluded, and 92 (30%) were enrolled and randomly assigned to a treatment group.

INTERVENTIONS: Ninety-two patients were enrolled in the study. Two patients never received the medication to which they were assigned, owing to administrative error; their data was not analyzed. Of the remaining patients, 31 were randomized to the PCA morphine group, 31 were randomized to the IM morphine group, and 28 were randomized to the IM ketorolac group. The randomly assigned drug was first administered in the post-anesthesia care unit. On arrival on the postoperative ward, the patient was asked to rate his or her pain using both a numerical rating scale and a visual analog scale at 30 minutes; 1, 2, 3, 4, and 6 hours after arrival on the ward; and every 4 hours throughout the first 5 postoperative days. The Mini-Mental State Examination (MMSE) was administered the day before surgery and then daily for the first 5 postoperative days. The first day the patient passed flatus after surgery was also recorded.

MAIN OUTCOME MEASURES: The end points analyzed were adverse effects, duration of postoperative ileus, degree of pain control, length of hospitalization, and development of postoperative confusion as measured on serial MMSEs.

RESULTS: Only two patients, both in the PCA group, reported adverse effects; neither required a change in analgesia group. Significantly more patients assigned to IM ketorolac broke protocol and required alternative analgesia than did patients in the morphine groups (32% ketorolac vs 16% IM morphine and 0% PCA). The ketorolac group had a significantly shorter duration of ileus than either morphine group (P<.0l). The ketorolac group also had significantly lower pain scores (P<.04) and less postoperative confusion than the morphine groups (P<.03), although these results are limited by missing values. The ketorolac group had a significantly shorter length of stay than either morphine group (P<.01), while there was no significant difference between the morphine groups (P=.75).

CONCLUSIONS: While it appears that ketorolac provides a better postoperative course than either IM or PCA morphine in terms of pain control, postoperative confusion, length of stay, and duration of ileus, 18% of our patients assigned to ketorolac required additional analgesia, and there was a strong patient preference for PCA. Most patients should probably be managed with PCA narcotics, but the addition of ketorolac might reduce narcotic dose and resultant adverse effects. Those patients particularly prone to adverse effects should receive primarily ketorolac.