Although opioids are widely used and effectively control postoperative pain, they contribute to the delayed recovery of gastrointestinal function. The aim of this study was to investigate the effects of intravenous patient controlled analgesia (iv PCA) with morphine, meperidine or fentanyl on postoperative bowel function.

Sixty ASA physical status I or II adult patients who were scheduled for elective gastrectomy were randomly allocated to morphine, meperidine, or fentanyl groups. After administering an initial bolus dose of morphine 5 mg, meperidine 25 mg, or fentanyl 50µg at OR, each iv PCA pump was started at PACU. The following program was used: morphine group-concentration 3 mg/ml, basal infusion rate 1.5 mg/hr, bolus 1.5 mg, meperidine group-concentration 15 mg/ml, basal infusion rate 7.5 mg/hr, bolus 7.5 mg, fentanyl group-concentration 30µg/ml, basal infusion rate 15µg/hr, bolus 15µg. The lockout time was 15 min in all groups. Postoperative pain at rest was evaluated with NRS (0-100) 6, 24, 48 and 72 hr after the end of surgery. Times from end of surgery to the passage of the first flatus were recorded.

Pain scores were comparable at rest in the three groups over the three postoperative days. Time from the end of surgery to the first postoperative flatus was 116.6 ± 13.2 hr in morphine group, 97.5 ± 17.6 hr in meperidine group, and 91.8 ± 19.1 hr in fentanyl group. Time from the end of surgery to first postoperative flatus was significantly longer in the morphine group than in the other two groups (P = 0.002, P = 0.000). Side effects were not significantly different among the groups.

Meperidine or fentanyl were found to have an advantage in terms of bowel function over morphine when used for iv PCA after gastrectomy.