THE INFLUENCE OF NITROUS-OXIDE ON RECOVERY OF BOWEL FUNCTION AFTER ABDOMINAL HYSTERECTOMY

The influence of nitrous oxide on the recovery of bowel function was s tudied in 36 patients anaesthetised for elective abdominal hysterectom y with or without salpingooophorectomy. Patients were randomly assigne d to receive either isoflurane in nitrous oxide and 30% oxygen (N2O gr oup) or isoflurane in air and 30% oxygen (Air group). Anaesthetic mana gement included thiopentone, fentanyl, suxamethonium and atracurium. T he lungs were not ventilated prior to intubation. Before closing the a bdomen, the surgeon assessed the degree of distension of the intestine s and the closing conditions. Postoperative nausea and vomiting was as sessed 2, 6, 12 and 24 h after recovery from anaesthesia. The lapse of time before mobilisation and passing of flatus and faeces was recorde d. The patients in the Air group were significantly older than the pat ients in the N2O group (48.9 years versus 44.0 years, P = 0.04); other wise, there were no differences in the demographic data of the patient s. We found no significant differences between the groups with respect to nausea and vomiting, distension of the intestines before closure o f the abdomen, closing conditions, time elapsing before mobilisation, constipation before recovery of bowel function or time elapsing before passing of flatus. We found a statistically significant delay of 10.3 h in time elapsing before passing of faeces in the N2O group compared to the Air group (P = 0.04), suggesting a potentially adverse effect of nitrous oxide. However, the delay seen in the present study is of d ubious clinical significance. In conclusion, regarding operating condi tions and time elapsing before recovery of bowel function, our results do not justify the omission of nitrous oxide from anaesthetics lastin g approximately 2 h or less.