Retrograde Amnesia Induced By General Anesthesia:A Prospective Clinical Observational Trial

Objective:To search for clinical evidence of retrograde amnesia effect under general anesthesia;To investigate the time of retrograde amnesia during general anesthesia.Methods:A total of 142 patients of elective surgery or recent non-operation under general anesthesia were selected as subjects.The surgical methods were general surgery laparoscopic surgery,gynecological laparoscopic or hysteroscopic surgery,urological cystoscopy or ureteroscopic surgery.Among them,47 patients(L group)were anesthetized for long time(>240min)and 47 patients(S group)were anesthetized for short time(<90min).The control group included 48 patients without recent history of surgical anesthesia(group C).Several time points were set at intervals of 10s,which were T-3,T-2...T2,T3.Rapid intravenous infusion of propofol(<10s)under general anesthesia was started in the L group and the S group at T0 with a dose of 1.5-2.0 mg/kg.Subjects were given a fixed sequence of picture learning tasks at each time point,one picture was learned and memorized at a time,and their vigilance/sedation score(OAA/S)was assessed and recorded until all picture learning was completed or subject consciousness was limited(OAA/S<2 points).After 24 hours,cognitive function and pain were assessed by MMSE and VAS.At the same time,the subjects were assessed for memory retention by the method of free recall and recognition of pictures,and the amnesia rate at each time point was calculated.Results:There were no significant differences in gender,age,education background and body mass index among the three groups(P>0.05).Compared with the S group,there was no difference in the drug dose induced by general anesthesia and postoperative MMSE score in the L group(P>0.05),while the VAS score in the L group was significantly higher than that in the S group(P<0.05).With the prolongation of operation time,the total amount of general anesthesia drugs and operation anesthesia time in group L were significantly higher than those in group S(P<0.05).The sedative effect of propofol infusion at T2 time point during induction of general anesthesia was significant(P<0.05).Compared with the control group,the free recall rate,recognition rate and memory retention rate of the L group and the S group all decreased significantly under the awake state(OAA/S=5 points),and the difference was statistically significant(P<0.05).There was no significant difference in the amnesia rate between the three groups at each time point(P>0.05),and no significant forgetting was observed at each time point before the onset of the sedative in the L group and the S group(P>0.05).Conclusion:General anesthesia reduces the familiarity of memory information and promotes the occurrence of amnesia,but there is no obvious retrograde forgetting effect.Prolonged general anesthesia did not increase the rate of amnesia rate.