[Evaluation of cognitive functions after anesthesia with propofol].

OBJECTIVES To assess the disturbances and delay of recovery of cognitive functions following propofol anaesthesia, and to evaluate a series of simple cognitive recovery tests. STUDY DESIGN Prospective comparative non randomized clinical study. PATIENTS Two groups of non premedicated patients, of ASA physical class 1 and 2 were studied. The control group (n = 11) included patients undergoing gastric fibroscopy under local anaesthesia. The propofol group (n = 22) consisted of patients scheduled for coloscopy under propofol anaesthesia. METHODS The gastric fibroscopy was performed under local anaesthesia with lidocaine and the coloscopy under general anaesthesia with propofol as the sole anaesthetic. Five cognitive tests, designed to assess short-term memory, delayed memory, the ability to plan complex tasks, attention, and language comprehension were conducted the day before, and 1 hour, 3 hours and 6 hours after the endoscopy. RESULTS The cognitive functions remained significantly depressed for at least 3 hours after anaesthesia, and recovered fully about 6 hours after the cessation of propofol administration. The capacity for planning was the most heavily affected. CONCLUSIONS Complete recovery can be evaluated by simple cognitive tests, which showed that cognitive functions are impaired over a longer period than psychomotor functions. Oral instructions may therefore not be fully understood by the patient within 3 hours after anaesthesia, emphasizing the importance of written instructions and the essential role played by a well-informed accompanying person.