Changes of Hemodynamics and Bispectral Index by Tracheal Intubation according to Effect-site Concentration of Remifentanil during Propofol Anesthesia

Abstract

Combination of propofol and remifentanil is an ideal regimen for total intravenous anesthesia, and the bispectral index (BIS) has been used as an indicator of the sedative state during anesthesia. This study examined the effect of remifentanil on the mean arterial pressure (MAP), heart rate (HR) and BIS to laryngoscopy and tracheal intubation with 4μg/ml of fixed target effect-site concentration infusion of propofol. Methods: In this double-blind study, fifty-one ASA physical status I-II patients, aged 20−60 yr undergoing elective surgery were randomly assigned to one of four groups according to the target effect-site concentration of remifentanil (0, 2, 3, 4 ng/ml). The target-controlled infusion (TCI) of remifentanil was initiated after the effect-site concentration of propofol was maintained with 4μg/ml. After target effect-site concentration of remifentanil was reached, a neuromuscular blockade was produced by rocuronium 1 mg/kg and tracheal intubation was performed after 90 seconds. MAP, HR and BIS were measured at pre-induction, after reaching target effect-site concentration of propofol and remifentanil, before and after tracheal intubation. Results: The changes of MAP, HR and BIS after tracheal intubation were negatively correlated with remifentanil effect-site concentration. Conclusions: Remifentanil attenuated the hemodynamic responses due to tracheal intubation and decreased BIS after tracheal intubation in a comparable dose-dependent fashion.