Recovery of bowel motility after surgery. Detection of time of first flatus from carbon dioxide concentration and patient estimate after nalbuphine and placebo.

Co-ordinated bowel motility has been studied after surgery. The time to first flatus (TFF) was noted by 20 patients aged 60 yr or older and measured simultaneously using a carbon dioxide analyser. After cystoscopy under general anaesthesia, 10 patients received nalbuphine 20 mg i.v., and 10 patients had placebo (normal saline). In 16 patients (80%) the two observed times coincided and there were no false reports. Two patients were asleep, and did not report TFF. In two others the sampling tube became obstructed. Therefore, both methods are of value; the carbon dioxide analyser, however, is a sensitive and accurate monitor of the initial passage of flatus which does not require patient co-operation. In the i.v. nalbuphine group, the median TFF was more than three times as long (212 min) as that in the placebo group (64 min) (P less than 0.01).