One hundred and one women (ASA grades I and II) were anaesthetized for
routine gynaecological surgery using an intravenous (i.v.) anaestheti
c technique combining propofol and alfentanil. The patients were alloc
ated randomly into groups. Group one received 33% oxygen in nitrous ox
ide and group two received 33% oxygen in air (total i.v. anaesthesia).
The group receiving nitrous oxide required significantly less (P<0.05
) of the propofol and alfentanil mixture to maintain anaesthesia and t
his was found to reduce the mean cost of anaesthesia by pound 1.70, (P
<0.05). There was no significant difference in the incidence of postop
erative complications between the two groups. We suggest that nitrous
oxide may be used to reduce the cost of total i.v. anesthesia with pro
pofol and alfentanil without causing any increase in post-operative mo
rbidity in patients undergoing routine gynaecological surgery.