Closed-Loop Coadministration Of Propofol And Remifentanil Guided By Narcotrend Index In Laparoscopic Cholecystectomy

ObjectiveTo investigate the feasibility of an algorithm of closed-Loop Coadministration of propofol and remifentanil guided by Narcotrend Index in laparoscopic cholecystectomy anaesthesia.MethodsSixty-four ASA Ⅰ～Ⅱ patients, aged23-67yr, scheduled for laparoscopic cholecystectomy undergoing general anesthesia were randomized into 2 groups:study group (group A, n=32) and control group (group B, n=32). Anesthesia was induced by two Agilia TIVA syringe pumps which used Schnider, Minto mode to target-controlled infusion of propofol and remifentanil. In group A, anaesthetist chose the initial propofol effect-site target concentration according to his/her clinical judgment and fixed the first remifentanil concentration according to the following rules. If the initial propofol target was<2.5 μg/ml, then the initial remifentanil target was 3 ng/ml; If the initial propofol target was between 2.5 and 2.9 ug/ml, then the initial remifentanil target was 3.5 ng/ml; If the initial propofol target was> 2.9 μg/ml, then the initial remifentanil target was 4 ng/ml. In group B, the anaesthetist chose the initial effect-site target concentrations of propofol and remifentanil for induction according to his/her clinical judgment. Anesthesia was maintained with the adjustment of effect-site concentration every 5minutes to maintain the NI at about 36 (26～46). Calculation and regulation of the effect-site concentration of group A are using the new algorithm. Group B adjusted based on clinical experience of the anaesthetist. Record the induction and maintain dose of propofol and remifentanil, the percentage of adequate anesthesia (defined as NI between 26 and 46), overshoot (NI<26),undershoot (NI>46) periods, and recovery time (defined as times of stopping the infusion of propofol to NI reach 80). Hemodynamic parameters(HR、MAP) were measured at different times before and after anesthesia induction, before and after CO2 inflation, before and after CO2 deflation.ResultsInduction dose of propofol were similar in two groups. Compared with group B, group A’s induction dose of remifentanil were more while the induction time were reduced. Heart rate, mean arterial pressure and NI were similar between groups before and after induction. IN the period of pneumoperitoneum, the hemodynamic parameters and NI were stabler in group A compared with group B. After CO2 deflation, the upward trend of HR and NI in group A showed significantly escalater than group B.ConclusionThe algorithm of closed-Loop coadministration of propofol and remifentanil guided by Narcotrend Index in laparoscopic cholecystectomy anaesthesia, better maintain NI within a predetermined range, stabler in hemodynamic in patients and of less propofol and remifentanilconsumption in continuous anesthesia, and recovery time is reduced.