Is nitrous oxide necessary for general anaesthesia?

BACKGROUND Nitrous oxide (N2O) has been used for about 150 years in clinical anaesthesia. Several recent reviews of the effect of nitrous oxide have concluded that there are certain contraindications to the use of this gas for general anaesthesia and its ecological effects, ozone depleting potential, immune depression and the proven factor of PONV have questioned the routine use of nitrous oxide in patients undergoing surgical procedures in general anaesthesia. METHODS This study comprised of 200 adult patients undergoing general anaesthesia with 40% O2 and Sevoflurane with and without N2O. All patients had standard anaesthetic care and monitoring with BIS monitoring in 120 patients. The effect of avoiding N2O was observed on anaesthetic perioperative management and haemodynamics, PONV and pain in PACU. RESULTS Demographic and perioperative characteristics were similar to both groups. Nitrous oxide free group needed only 0.233% (mean) more Sevoflurane. There was a marked reduction in incidence of PONV (11% to 5%) in N2O free group. Duration of surgery (97.72 +/- 52.393 in N2O group, 103.75 +/- 48.671 in N2O free group) and induction dose of propofol (155.30 +/-38.572 in N2O group and 158.50 +/- 36.164 in N2O free group) did not differ significantly in the two groups. CONCLUSION The omitting of N2O from anaesthetic regimen has a substantial impact on patient comfort after surgery by reducing incidence of PONV and it does not have any justifiable indication of its use in General anaesthesia.