The Influence Of Lidocaine On Sedation Caused By Propofol Monitored By BIS And CSI

Objective:To investigate the influence of lidocaine in sedation cause by target control infusion (TCI) of propofol and its mechanism. To investigate the effectiveness of bispectral index (BIS) and cerebral state index (CSI) in measuring this anaesthesia project.Methods:45 patients aged 20-50 years old who were undergoing lower abdominal or lower limb surgery were divided into 3 groups(n=15). Group A (control group)was given 0.2ml/kg saline i.v.; Group B was given 2mg/kg 1% lidocaine i.v.; Group C was given epidurally 2mg/kg 1% lidocaine.10 minutes later, anesthesia was induced with TCI of propofol. The target effect-site concentration was set initially at 0.5ug/ml followed by increments of 0.5ug/ml every 5 min until 5 min after the patients lost consciousness and did not respond to pain stimulation (OAA/S=0).CSI and BIS were recorded, sedation level were recorded every 20s during stepwise increase(target-controlled infusion,0.5ug/ml) of propofol until the patients lost response. BP, HR, SPO2 were monitored and recorded at each effect-site concentration(CE)before intubation.Results:The three groups were comparable with respect to sex(M/F ratio), weight and height. In group B, BIS and CSI decreased after the administration of iv lidocaine. In group C, BIS and CSI didn't decreased after epidural lidocaine. In group C, the effect-site concentration of propofol when OAA/S=2,1,0 were significantly less than that in group A. In three groups, BIS and CSI highly correlates with the effect-site concentration, and correlates good with sedation level.Conclusion:1. The administration of iv 2mg/kg lidocaine can only inhibits electrical activity of brain, but does not enhance sedation cause by propofol.2. The administration of epidural lidocaine enhances sedation cause by propofol significantly. The effect-site concentration of propofol when OAA/S=2,1 significantly decreases when patients received epidural lidocaine.3. Both BIS and CSI can be used to evaluate the sedation level.