Rectal indomethacin reduces postoperative pain and morphine use after cardiac surgery

To evaluate the combination of rectal indomethacin with patient controlled intravenous morphine analgesia (PCA) on postoperative pain relief and opioid use after cardiac surgery.

With institutional ethics approval, 57 consenting adults undergoing elective aortocoronary bypass surgery were randomly assigned preoperatively in a double-blind fashion to receive either placebo (n = 26) or indomethacin 100 mg suppositories (n = 31), 2-3 hr postoperatively, and 12 hr later. Both groups utilized PCA morphine. Pain scores in the two treatment groups were assessed on a 10-cm visual analogue scale (VAS) (at rest and with cough) at 4, 6, 12, 18 and 24 hr after initial dosing, and were analyzed through a 2 x 5 repeated measures of variance. The 24 hr analgesic consumption, 12 and 24 hr chest tube blood loss, and time to tracheal extubation were also recorded, and compared for the two treatment arms through Student's t test on independent samples.

Postoperative morphine consumption in the first 24 hr was 38% less in the indomethacin group (22.40 +/- 12.55 mg) than the placebo group (35.99 +/- 25.84 mg), P = 0.019. Pain scores, measured with a VAS, were 26% to 66% lower in the indomethacin vs placebo group at rest (P = 0.006), but not with cough, for all times assessed. There was no difference in blood loss (at 12 hr) or time to tracheal extubation for both groups.

The combination of indomethacin with morphine after cardiac surgery results in reduced postoperative pain scores and opioid use without an increase in side effects.