BACKGROUND: Lidocaine has been used for attenuating cardiovascular responses to endotracheal intubation and thought to have the sedative effect. The sedative effect of lidocaine has not been known well. The BIS (bispectral index) has been used an indicator of the sedative state and has been considered to be related to anesthetic agents and noxious stimulus. The purpose of this study is to evaluate sedative and cardiovascular effects of lidocaine during TCI (target controlled infusion) of propofol by monitoring BIS and hemodynamics.

METHODS: Fifty ASA patient status 1 and 2, aged from 20 to 65 years patients (n = 50, 2 groups) undergoing elective surgeries with general anesthesia. These patients were randomly allocated to group C or L. Patients in Group L received 1.5 mg/kg injection and 40µg/kg/min infusion of lidocaine. Patients in Group C received normal saline. The BIS, blood pressure and heart rate were mesasured before injection of drug, 1, 2 minute after injection of drug, just before intubation, 1, 2, 5 and 10 min after intubation.

RESULTS: The BIS of group L more decreased than group C at 1, 2, 5 and 10 min after endotracheal intubation. The blood pressure and heart rate did not show any differences between two groups.

CONCLUSIONS: Intravenous injection of lidocaine reduced BIS. Lidocaine had sedative effects under propofol target controlled infusion. But Cardiovascular variables of this study failed to show any differences between two groups (P < 0.05).