RESUMO
Objective To investigate the effects of different BIS values on postoperative cogni-tive dysfunction (POCD)and S100βprotein(S100β)in the early stage of postoperation.Methods Fifty patients who were scheduled for selective abdominal surgery under general anesthesia (male 34 cases, female 1 6 cases,aged 65 to 75 years,ASA Ⅰ or Ⅱ)were randomly divided into two groups:light anesthesia group (group L,n =25,BIS value was maintained at 50 to 59)and deep anesthesia group (group D,n =25,BIS value was maintained at 30 to 39).BP,HR,SpO 2 ,ECG,PET CO 2 ,inhaled anes-thetic concentration and BIS values were recorded on time points of 5 minutes after the patients ente-ring the operating room (T0 ),before endotracheal (T1 ),intubation (T2 ),incision (T3 ),two hours after incision (T4 ),three hours after incision (T5 )and at the end of surgery (T6 ).The procedure du-ration,anesthesia time,dosages of propofol,fentanyl,midazolam and VAS scores on 1 d after sur-gery were also recorded.Blood samples were collected on time points of 10 min before anesthesia,im-mediately after surgery and 24,48 h after operation.S100β concentration were detected.Mini-mental State Examination (MMSE)score and Trail Making Test (TMT)completion time were recorded on 1 d before surgery and 1,3,7 d after surgery.Results BIS value of group D were lower than group L on T2 ,T3 and T4 .The propofol dosage of group D was significantly greater than that in group L (P <0.05 ).The concentration of serum S100βincreased significantly immediate and 48 h after operation in both groups compared with 10 min before anesthesia(P < 0.05).It was still higher 24 hours after op-eration than before anesthesia.But there was no statistic difference.Compared with the end of surger-y,the concentration of serum S100βin two groups on 24 h after surgery were significantly decreased (P < 0.05 ).The concentration of serum S100β in group L on the end of surgery and 24 h after surgery were higher than that in group D significantly (P <0.05).Compared with 1 d before surgery, postoperative 1 d MMSE scores in two groups and postoperative 3 d MMSE score in group L de-creased significantly (P <0.01).Compared with postoperative 3 d,postoperative 7 d MMSE score in group L increased significantly (P <0.01).Postoperative 1,3 d MMSE score in group D were signifi-cantly higher than group L (P <0.05).Compared with 1 d before surgery,TMT completion time in two groups on 1 d after surgery were significantly prolonged (P <0.01 ).Compared with 1 d after surgery,TMT completion time in two groups on 3 d after surgery were significantly shortened (P <0.01).Compared with 3 d after surgery,TMT completion time in group L on 7 d after surgery was significantly shortened (P <0.01 ).TMT completion time in group D on 1,3 d postoperative were significantly shorter than group L (P <0.05).POCD incidence of group D on 1 d after surgery was lower than that in group L (P < 0.05).Conclusion Different depth of anesthesia can ensure hemo-dynamic balance in old patients during surgery and after surgery.When BIS value was maintained at 30 to 39,it had lower S100βprotein levels,lower incidence of early POCD and a lesser degree of post-operative cognitive dysfunction.