Closed-loop Target Controlled Infusion System For Propofol Guided By Bispectral Index Applied To Beach Chair Arthroscopy

?Objective?Through comparative study of the effect of closed-loop and open-loop TCI mode of propofol guided by BIS on perioperative period of patients undergoing beach chair arthroscopy;to explore the advantages of closed-loop TCI of propofol guided by BIS,and the safety and effectiveness of this surgical position,and providing reference for clinical anesthesia.?Methods?60 patients,ASA I~II,undergoing beach chair arthroscopy were randomly divided into groups with either open-loop(O)group or closed-loop(C)group by block randomization.Ultrasound-guided brachial plexus block performed in both groups.During the anesthesia maintenance,BIS value was used as the feedback variable for target control infusion of propofol,and manual control or automatic control modes were used according to the grouping.Target controlled infusion of remifentanil was manually controlled,and the effective concentration was adjusted within 2-6ng/ml according to the surgical conditions.Then the stability of BIS,and the mean dose of propofol,remifentanil,muscle relaxant,vasoactive agents should be compared.And the index such as MAP,HR and BIS values after intubation for 5min and 10 min in supine position and 5min,10 min,15min and 20 min in beach chair position of the two groups should be compared.MMSE score 1 day before and 1 day after surgery,serum GFAP and S100? proteins before anesthesia,after extubation and 1 day after surgery should also be compared.?Results?The GS of group C was lower than that of group O,which show significant difference(P < 0.05).The proportion of appropriate anesthesia time in group C was significantly higher than that in group O(P < 0.05).The time of BIS<40 in group C was lower than that in group O(P < 0.05);and the time of BIS>60 were undifferentiated between the two groups.The dosage of propofol in group C was significantly lower than that in group O(P < 0.05).The MAP,HR and BIS at various time were both undifferentiated(P>0.05)between the two groups.The MMSE scores of the day before surgery and the day after surgery were both undifferentiated(P>0.05)between the two groups.The GFAP and S100? protein concentrations were both undifferentiated(P>0.05)between the two groups at each time point.?Conclusion?In the anesthesia maintenance stage,compared with open-loop TCI,the closedloop TCI of propofol guided by BIS could shorten the time of BIS <40,reduce the dosage of propofol,and would not increase the incidence of postoperative cognitive dysfunction and intraoperative hemodynamic fluctuations,which is worthy of clinical promotion.