Abstract: AIM: To observe the relationship between the level of catecholamine with bispectral index during endotracheal intubation with propofol anesthesia in order to investigate the mechanism of the preventing of endotracheal intubation response with lidocaine.METHODS: Sixty patients were randomly allocated into two groups:control group (Group C) and lidocaine group (Group L). The patients received lidocaine 1.5 mg/kg in Group L and saline in Group C before induction of anesthesia. Anesthesia was induced with propofol (2 mg/kg) and fentanyl (4 μg/kg) and tracheal intubation was facilitated with rocuronium (0.6mg/kg) in all patients. Bispectral index (BIS), systolic pressure(SP), diastolic pressure(DP)and heart rate(HR)were continuously monitored and recorded before induced of anesthesia(T₀), preintubation(T₁),immediately and 1,3 min after intubation (T_2-4). Arterial blood samples were obtained at T₀, T₁ and T₃ for determination of plasma concentration of adrenaline (Ad) and noradrenaline(NA).RESULTS: SP, DP,HR were significantly increased after intubation in Group C compared with baseline values at T₀(P<0.05),while plasma Ad and NA concentrations at T₃ were of no statistic significance(P>0.05). Compared with Group C, BIS value at T₁ to T₄ decreased significantly in Group L(P<0.05). Plasma Ad and NA were lower at T₃ in Group L than those in Group C and T₀(P<0.05).CONCLUSION: Lidocaine can further reduce BIS value and the plasma concentration of catecholamines during propofol anesthesia, indicating the sedative and anti-nocieptive effect of intravenous lidocaine. Lidocaine(1.5 mg/kg)can restrain the changes of BIS and reduce stress reaction caused by tracheal intubation.

Key words: Lidocaine, Intubation, Intratracheal, Catecholamines, Electroencephalography, Hemodynamics