Conscious awareness and memory during general anesthesia

Conscious awareness is an infrequent complication of general anesthesia. All methods of anesthesia have been implicated, and no method guarantees amnesia. This article examines implicit and explicit memory and discusses factors associated with awareness. Common methods of detection are unreliable, and symptoms resembling post-traumatic stress disorder may result if awareness goes unrecognized and untreated. Patients who experience awareness may sue on grounds of malpractice, breach of contract, and lack of consent. Overhearing negative stimuli may affect patient outcome, because learning and language comprehension can occur during what appears to be clinically adequate anesthesia. Strategies to block threatening auditory stimuli include use of earphones, music tapes, white noise, reassuring statements, or positive suggestion. Behavioral anesthesia decreases patient stress to enhance recovery. Evidence of patient benefit resulting from therapeutic suggestion is inconclusive.