SUBANESTHETIC CONCENTRATIONS OF DESFLURANE AND PROPOFOL SUPPRESS RECALL OF EMOTIONALLY CHARGED INFORMATION

Whether anesthetized patients register emotionally charged information remains controversial. We tested this possibility using subanesthetic concentrations of propofol or desflurane. Twenty-two volunteers (sele cted for hypnosis susceptibility) received propofol and desflurane (on separate occasions, and in a random order) at a concentration 1.5-2 t imes each individual's minimum alveolar anesthetic concentration (MAC) -awake (or equivalent for propofol). We gave vecuronium, intubated the trachea of each volunteer, controlled ventilation, and then presented a neutral (control) drama or a ''crisis'' drama stating that the oxyg en delivery system had failed, assigning crisis and control dramas in a blinded, randomized, and balanced manner. One day later, interviewer s blinded to the assigned drama conducted a 2-h structured interview ( including hypnosis) to determine whether the contents of the interview s after crisis and control dramas differed. In addition, messages perm itting subsequent assessment of learning of matter-of-fact information (Trivial Pursuit-type question task and a behavior task) were present ed at the anesthetic concentration just sufficient to prevent response to command in each volunteer. No analyses of the tasks involving matt er-of-fact information revealed learning except one which correlated h ypnosis susceptibility with behavior task performance. Both propofol a nd desflurane suppressed memory of the crisis. Consistent with previou s findings for isoflurane and nitrous oxide, propofol and desflurane s uppressed learning of matter-of-fact information at concentrations jus t above MAC-awake, except that volunteers' susceptibility to hypnosis correlated with performance of a behavior suggested during anesthesia. Propofol and desflurane suppressed learning of emotionally charged in formation at anesthetic concentrations 1.5-2 times MAC-awake (less tha n MAC), a different result from that previously reported for ether.