| Objective: To study the effect of different depths of anesthesia on perioperative neurocognitive impairment in elderly patients undergoing thoracic surgery under the monitoring of BIS.Methods: Eighty-six patients,aged 65-80 years,undergoing optional pleuroscopic lobectomy in Yanbian University Affiliated Hospital from September 2020 to December 2021 were selected.Patients were divided into two groups with 43 patients in each group,one is deep anesthetic group(Group A)and the other is light anesthetic group(Group B).The intraoperative EEG bifrequency index(BIS)was maintained between 40 to 50 in the deep anesthesia group,while 51 to 60 in the light anesthesia group.All patients were anesthetized with a double-lumen bronchial tube(DLT)using a combination of static and suction.Mean arterial pressure(MAP),heart rate(HR)and BIS value were recorded before induction of anesthesia(T0),at the start of surgery(T1),30 min after the start of surgery(T2),immediately after the end of suturing(T3),and 30 min after the recovery of orientation(T4).The time of anesthesia,time of operation,time of awakening,time of extubation and time of recovery of directional force were recorded in both groups.Patients were interviewed on postoperative day 1 using the modified Bryce scale and assessed for the occurrence of intraoperative knowledge.Patients in both groups were followed up on preoperative day 1 and postoperative days 1,3 and 7,and cognitive function was assessed using the Simple Mental State Examination Scale(MMSE)and the Montreal Cognitive Assessment Scale(Mo CA).Results: At T1 and T2,MAP and HR were significantly higher in group B than in group A,(P <0.05);at T0,T3 and T4,there was no statistical difference in MAP and HR between the two groups(P > 0.05);MAP and HR were reduced at T1 and T2 in both groups compared to T0,(P< 0.05);compared with T0,there was no significant flucation in MAP and HR at T3 and T4 in group A and group B,and there was no statistical difference(P > 0.05);compared with T1 and T2,MAP and HR increased at T3 and T4 in both groups,(P < 0.05);compared with T1,no significant changes in MAP and HR at T2 in group A,and no statistical difference(P >0.05);,MAP and HR were higher in group B at T2 compared to T1,(P < 0.05).The duration of surgery and anaesthesia were no statistically different between the two groups(P > 0.05).The mean BIS value was 44.74 ± 2.77 in group A at T1,44.81 ± 2.87 in group A at T2,55.58 ± 2.95 in group B at T1,and 54.84 ± 2.94 in group B at T2.The BIS value was higher in group B than in group A at T1 and T2,(P < 0.05).The time to awaken was longer in group A than in group B(25.21 ± 6.51 min vs.18.21 ± 4.49 min,P < 0.05);the time for extubation was longer in group A than in group B(28.19 ± 5.17 min vs.19.42 ± 5.04 min,P < 0.05);the time for recovery of orientation was no statistically different between groups A and B(24.23 ± 5.93 min vs.23.21 ±5.42 min,P > 0.05).There was no intraoperative knowledge in either group.MMSE and Mo CA scores were no different between the two groups at 1 day before surgery and 7 days after surgery(P > 0.05),however,group A had higher MMSE and Mo CA scores than group B on postoperative days 1 and 3(P < 0.05).Conclusion:1.Maintaining deep anesthesia(BIS value 40-50)is effective in reducing the occurrence of perioperative neurocognitive impairment compared to light anaesthesia(BIS values 51-60)in elderly patients under BIS monitoring for thoracic surgery.2.Intraoperative patient hemodynamics are more stable during deep anesthesia(BIS values40～50). |
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