异丙酚预期浓度和双频指数对意识消失的预测概率比较

Comparision of the prediction probability of unconsciousness of target concentration and bispectral index during propofol sedation

目的 比较预期血药浓度、效应室浓度和BIS等指标对意识消失预测概率 (Pk)。方法 选择ASAⅠ～Ⅱ级的择期手术患者 12例 ,以血药浓度为靶控目标浓度 ,预期血药浓度梯度为 0 5～ 1mg/L ,上下调整靶控目标浓度给予术中镇静 ,每一预期浓度维持 12min。双盲记录预期浓度、EEG参数、意识状态并计算各指标的意识消失的预测概率 ,比较预测概率的差异。结果 预期血药浓度、效应室浓度和BIS等指标预测意识消失的Pk 平均值分别为 :0 841,0 90 8和 0 817。效应室浓度与各指标的Pk 值之间差异有显著性 (P <0 0 5 )。结论 预期血药浓度、效应室浓度和BIS等指标均能用于预测意识消失和判断镇静深度 ,其中效应室浓度的预测价值最大。

Objective To study the performance of target propofol effect-site concentrations, plasma concentrations, bispectral index to predict loss of consciousness during propofol sedation. Methods Twelve patients (ASA physical status Ⅰ～Ⅱ) were anesthetized with target concentration of propofol, which was increased by an increment of 0.5～1 mg/L until loss of consciousness, and decreased by an increment of 0.5～1 mg/L until return of consciousness. This was repeated until patients 'crossed over' from unconsciousness to consciousness several times. The times of loss of consciousness and return of consciousness and BIS were recorded. The prediction probability (P k) of indicators was calculated and compared. Results Bispectral index (P k=0.817) and target plasma concentration (P k=0.841) differ significantly from propofol effect-site concentration (P k=0.908) in their ability to predict loss of consciousness. Conclusion Target plasma concentration, effect-site concentration and BIS can be used to predict unconsciousness and estimate sedation level during propofol anesthesia. Effect-site concentration is the best indicator in predicting depth of sedation.