Immediate peri-operative memory

Information about anterograde and retrograde amnesias in the immediate peri-operative period is scarce. During this period, assessment of memory for real-life events is also rare. We hypothesized that there would be both anterograde and retrograde amnesias and memory for peri-operative events would be better than for verbal memory.

We studied 40 patients who underwent general anesthesia and surgery and 19 control volunteers who were matched to the patients but did not have surgery. Patients completed the state anxiety part of the Spielberger State-Trait Anxiety Inventory in the pre-operative period. They were presented with three word lists in the holding area, the operating room before induction of anesthesia and the recovery room. Memory for the words was tested the next day by recall and recognition tests. Memory for events that happened on the day of surgery was tested by administering a questionnaire. The control subjects were tested similarly but did not complete the events questionnaire. Retrograde amnesia would be demonstrated by a decline in patients' memory from the holding area to the operating room which exceeded any corresponding changes in controls; anterograde amnesia would be demonstrated by memory impairment of the patients in the recovery room, relative to controls.

Recall and recognition of words were significantly impaired in the recovery room with a decline from 12% in the holding area to zero% in the recovery room for recall and from 43% to 7% for recognition. The decline in memory from the holding area to the operating room was not significantly greater in patients than in controls, 80% vs. 56% for recall and 27% vs. 14% for recognition. There were no significant differences for recognition of events which happened in the three rooms.

We were unable to detect retrograde amnesia. Patients' memory for neutral stimuli in the recovery room was severely impaired. The events questionnaire proved to be insensitive.