No abstract

The purpose of this study was to evaluate effects of remifentanil, esmolol, and lidocaine administered before a tracheal intubation on the autonomic nervous system using heart rate variability. Methods: In a randomized, prospective trial, we enrolled 60 patients undergoing a tracheal intubation under general anesthesia. After an induction of anesthesia using propofol and rocuronium, patients received either remifentanil 1.0 µg/kg (group R), esmolol 1.0 mg/kg (group E), or lidocaine 1.5 mg/kg (group L). Standard deviation of the normal to normal interval (SDNN), low frequency power (LF), and high frequency power (HF) were measured before and after the administration of three drugs. Heart rate and mean arterial pressure were measured before and after the tracheal intubation. Results: SDNN was not different between three groups. After the administration of drugs, LF mainly indicating the sympathetic nervous system activity was lower in the group E than in group R and L. HF indicating the parasympathetic nervous system activity was higher in group R than in group E and L. After the tracheal intubation, heart rate was lower in group R and E than in group L. Mean arterial pressure was lower in group R than in group E and L. Conclusion: Hemodynamic changes according to the tracheal intubation were attenuated by remifentanil 1 µg/kg or esmolol 1 mg/kg, not by lidocaine 1.5 mg/kg. Remifentanil stimulated parasympathetic nervous system and esmolol suppressed sympathetic nervous system.