Lidocaine does not prevent bispectral index increases in response to endotracheal intubation

We investigated the effect of IV lidocaine on the hemodynamic and bispectral index responses to induction of general anesthesia and endotracheal intubation. Forty patients (ASA I) were randomly allocated into 2 groups of 20 to receive normal saline or lidocaine 1.5 mg/kg IV 30 s after induction. Ninety seconds later, endotracheal intubation was performed. Systolic blood pressure, heart rate, and bispectral index were measured at baseline, 1 min after induction, at preintubation, and every minute until 5 min after endotracheal intubation. Bispectral index at 1 min after induction and preintubation in the lidocaine group were significantly lower compared with the control group (P < 0.05). Systolic blood pressure increased significantly at 1 and 2 min after intubation in the control group compared with the baseline value (P < 0.05) but did not increase significantly in the lidocaine group. Heart rate increased at 1 to 3 min in both groups (P < 0.05), but there was no significant difference between the two groups. One patient in the control group had recall of the procedure. We conclude that the administration of IV lidocaine (1.5 mg/kg) does not suppress the hypnotic response to endotracheal intubation.