Nitrous oxide does not influence the surgeon's rating of operating conditions in lower abdominal surgery.

The present study was initiated to evaluate the effects of nitrous oxide on the surgeon's ratings of operating conditions in lower abdominal surgery. Forty patients without known gastrointestinal disorder, scheduled for elective hysterectomy were randomized into one of two groups. In both groups anaesthesia was induced with propofol and endotracheal intubation was performed after administration of vecuronium 0.1 mg kg-1 and anaesthesia was maintained by a propofol infusion. One of the groups was ventilated with O2/air while the other group received nitrous oxide (70%) instead of air. The surgeons were asked to score the operating conditions at the beginning of surgery, when the abdomen was opened, and at the end of the operation, when the peritoneum was to be closed. No difference in rating of operating conditions was found between the two groups. We conclude that the administration of 70% nitrous oxide to patients undergoing lower abdominal surgery does not influence the surgeons ratings of operating conditions.