Sixty patients participated in an evaluation of memory during elective surgery performed under a type of neuroleptanesthesia in which diazepam and morphine were used as adjuncts to the nitrous oxide (N20)-curare technic. All patients were tested for recall of preinduction and postinduction events. In addition, patients in the experimental group heard word-pairs and neutral narrative passages through earphones at various times during operation; control patients wore the earphones but did not hear any of the taped materials.
In general, patients had good recall of the preinduction period. Anesthesia was induced in all patients in approximately 2 minutes, and was accompanied by a deep sleep or amnesic state that lasted for the duration of the operative procedure. A small number (n = 9) of the patients reported vague recall of dreams, and events occurring immediately prior to (n = 2) or following (n = 5) operation. However, none reported that these recollections were in any way upsetting or distressing to them.
It is concluded that the administration of a benzodiazepine tranquilizer (diazepam) and a narcotic analgesic (morphine) as adjuncts to NL.0-curare anesthesia results in a type of neuroleptanesthesia that, in addition to producing satisfactory anesthesia for major surgery, also offers considerable assurance that there will be no recollection or awareness during the operative procedure.