Perioperative CNS Dysfunction—Diagnosis and Management

Abstract

All agents used for premedication, induction, and maintenance have lingering, usually subtle, CNS effects. Even “short-acting” agents may have unusual and relatively long effects if one looks carefully enough. For example, reports show that midazolam’s effect on memory is similar in duration to that of diazepam. Similarly, a single dose of methohexital alters performance on psychomotor testing for 12 hours. Propofol produces more rapid awakening and recovery of cognitive and psychomotor skills following short procedures than methohexital or thiopental, but is occasionally associated with vivid dreams and hallucinations. Induction and maintenance of anesthesia for only 3.5 minutes with halothane or enflurane impairs psychomotor performance for 5 hours. As the duration of anesthesia increases, so too does the duration of postanesthetic CNS impairment. Of course with newer agents such as desflurane, the duration of impairment is shorter.