Dose-response Relationship Between Propofol And Burst Suppression Ratio And The Influence Of Combination With Remifentanil

Objective:To investigate the influence of propofol on burst suppression ratio, see if combination of remifentanil changes it. Assess the value of BSR in monitoring depth of anesthesia. Besides, identify the effect-site concentration of propofol-induced burst suppression and analyse the influence on it after administration of remifentanil, thus provide reference for clinical applications so we can exactly administrate.Methods:34ASA physical status Ⅰ-Ⅱ, aged18to50years old, undergoing general anesthesia patients were randomly divided into two groups (n=17). Group A received4000mg/h propofol until either the burst suppression ratio (BSR) up to70%or the consumption of propofol greater than500mg.Fentanyl and muscle relaxants were given for intubation. Group B first target-controlled infuses remifentanil. Target-controlled settings:plasma concentrations, Minto drug pharmacokinetic parameters, target concentration4ng/ml. After10min of target concentrations achievement, begin the same protocol of group A. The effect-site propofol concentration were calculated by the pharmacokinetic model described by Marsh. Results:BIS and BSR in both groups show a good dose-response relationship with the effect-site propofol concentration. In group A, EC50of propofol-induced EEG burst suppression is8.06±2.29ug/ml, CBSR10is5.97±2.11ug/ml. In group B, EC50of propofol-induced EEG burst suppression is8.80±2.15ug/ml, CBSR10is5.75±2.22ug/ml. There were no significant differences in EC50、CBSR10of both groups.Conclusion:1. Both BIS and BSR show a good correlation to propofol effect-site concentration, EC50of propofol-induced EEG burst suppression is8.06±2.29ug/ml, CBSR10is5.97±2.11ug/ml.2. Target controlled infusing4ng/ml of remifentanil has no significant effect on the propofol-induced EEG burst suppression.