Abstract
Plastic surgery patients undergoing either local (LA) or general (GA) anaesthesia of at least forty-five minutes' duration and a non-patient control group were used to examine the extent and duration of deterioration in mental functioning following GA and the factors influencing such deterioration. Mental functioning was assessed by a battery of six tests administered one week before anaesthesia, four days after anaesthesia and six weeks after anaesthesia. Mental performance of GA patients but not of LA patients was significantly impaired on the fourth postoperative day. Six weeks after anaesthesia GA patients were still performing significantly below controls. There was marked variation in the pattern of recovery, some GA patients failing to regain their pre-operative level of performance after six weeks. Severity of deterioration following general anaesthesia was significantly correlated with habitual caffeine consumption.