The Effect-Site Concentration of Remifentanil for Prevention of Increase of Blood Pressure and Heart Rate to Tracheal Intubation during Propofol-Remifentanil Total Intravenous Anesthesia in Korean

Abstract

Background: Combination of propofol and remifentanil is an ideal regimen for total intravenous anesthesia. The purpose of this study is to determine the effect-site concentration of remifentanil for prevention of hemodynamic responses to tracheal intubation during fixed propofol infusion (4g/ml) and to find any sexual differences. Methods: Thirty ASA physical status I-II patients undergoing general anesthesia were assigned to male (n = 15), and female (n = 15) group. All patients received a target controlled infusion (TCI) of propofol with a fixed effect-site concentration of 4g/ml. After target effect-site concentration of propofol and remifentanil was reached, tracheal intubation was performed. The hemodynamic changes (systolic/diastolic blood pressure, mean arterial pressure, and heart rate) were measured at 1 and 2 min before tracheal intubation (baseline), immediately after, 1, 2, 3, 4 and 5 min following tracheal intubation. In both groups, effect-site concentration of remifentanil was initiated with 3 ng/ml. Subsequent concentration of remifentanil was determined by hemodynamic responses of the previous patient to tracheal intubation based on up and down sequential allocation. Results: The mean EC50 of remifentanil for prevention of hemodynamic responses to tracheal intubation were 1.37 ng/ml (95% CI, 0.95-1.81 ng/ml) in male group and 1.05 ng/ml (95% CI, 0.68-1.40 ng/ml) in female group, respectively. In addition, there were no statistical significant differences between two groups. Conclusions: Relatively small dosages of remifentanil (0.68-1.81 ng/ml) for attenuation of hemodynamic responses to tracheal intubation was needed in Korean population in propofol TCI and there were no sexual differences.