A Comparison of Psychologic Responses to Ketamine and Thiopental–Nitrous Oxide–Halothane Anesthesia

Subjective psychologic responses to ketamine and to thiopental–nitrous oxide–halothane anesthesia, with two levels of preoperative information, were investigated in 48 young servicemen in a randomized, blind, prospective study. Ketamine produced a uniformly high incidence of illusions in both information groups, suggesting an intrinsic pharmacologic property of this drug. The combination of thiopental, nitrous oxide, and halothane also produced illusions, but their incidences were significantly lower than those with ketamine. The incidence of postoperative anxiety was no greater in patients who received ketamine than in those receiving thiopental–nitrous oxide–halothane. Patients who had received ketamine, with one exception, found the agent acceptable unless depth of anesthesia was inadequate to eliminate awareness during operation.