A comparison of memory under three methods of anaesthesia with nitrous oxide and curare.

Sixty-three volunteer patients participated in an investigation disigned to evaluate memory of the surgical experinece with three different methods of balanced nitrous oxide-curare anaesthesia. Two of the methods (Liverpool and Roosevelt protocols) used thiopentone for induction but did not utilize any neuroleptic drug, while the third (Diazepam protocol) used the tranquilizer diazepam in combination with morphine for both premedication and induction. In general, the results suggest that all three variations are successful in producing anaesthesia and that patients have no recall of the major portion of the surgical procedure. The major differences among the groups were exhibited in the post-operative periods. These findings suggest that diazepam affects the emotional quality associated with memory and thus aids the patients by reducing both the incidence of noxious psychological reactions and the possibility of severe emotional trauma. Finally, the findings also suggest the importance of using a narcotic analgesic as part of nitrous oxide-curare anaesthesia.