靶控异丙酚时不同意识状态的预测效应部位浓度及与BIS和CSI的关系

目的：探讨靶控异丙酚镇静的患者在出现语言反应消失及意识消失时的异丙酚预测效应部位浓度值，以及麻醉深度指数（cerebral state index，CSI）和脑电双频谱指数（bispectral index，BIS）与预测效应部位浓度的关系。方法：ASAⅠ～Ⅱ级患者20例，所行手术不限，诱导插管前均予以异丙酚靶控输注镇静，靶浓度从0．5mg／L开始递增，递增梯度为0．5mg／L，每一靶浓度输注5min，直至改良清醒镇静评分（observer’s assessment of alertness／sedation scale，OAA／S）为O后5min停止，试验中监测并记录患者CSI值及BIS值。每间隔20S行改良OAA／S评分，记录靶控输注系统预测效应部位浓度值每变化0．1mg／L时的预测效应部位浓度数值及时间。计算5％，50％及95％患者在丧失语言反应及意识消失时的预测效应部位浓度、BIS和CSI值。结果：异丙酚预测效应部位浓度值与BIS和CSI均呈较好的线性关系（R^2分别为0.787与0.792）。5％，50％及95％患者出现语言反应消失时的异丙酚预测效应部位浓度值分别为1、1，1、8与2．4mg／L；5％，50％及95％患者出现语言反应消失时的BIS值分别为79、2，69．2与59．2；CSI值分别为74.9，65.9与56.8。5％，50％及95％患者出现意识消失时的预测效应部位浓度值分别为1．5，2．5与3．4mg／L；BIS值分别为73.6，57．1与40.6；CSI值分别为65．2，54．8与44．3。结论：靶控异丙酚时患者出现语言反应消失及意识消失时预测效应部位浓度值总是在一定的范围波动；异丙酚预测效应部位浓度值与BIS和CSI均呈较好的线性关系；与BIS比较，出现意识状态改变时CSI数值变化范围较小，用于反映麻醉中患者语言反应消失及意识消失可能更有效。

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OBJECTIVE: To examine the predicted effect-site concentration of propofol at two clinical end-points: loss of verbal contact (LVC) and loss of consciousness (LOC), and to explore the relationship between bispectral index (BIS) values, cerebral state index (CSI) values and the predicted effect-site concentration during the target-controlled infusion of propofol. METHODS: In 20 patients during the target-controlled infusion of propofol, the propofol infusion was set at an initial effect-site concentration of 0.5 mg/L, and increased by 0.5 mg/L every 5 min until 5 min after the modified observer's assessment of alertness/sedation scale (OAA/S) values reached zero. The predicted effect-site concentration of propofol, the values of CSI and BIS were recorded, and the sedation level was examined by the modified OAA/S every 20s. The predicted effect-site concentrations of propofol in target-controlled infusion (TCI) system were recorded when they increased by more than 0.1 mg/L. The predicted effect-site concentrations of propofol and the values of BIS and CSI at LVC and LOC in 5%, 50% and 95% of the patients were calculated. RESULTS: There was good linearity between BIS and the predicted effect-site concentration of propofol (R(2)=0.787), as well as between CSI and the predicted effect-site concentration of propofol (R(2)=0.792). The predicted effect-site concentrations of propofol at LVC in 5%, 50% and 95% of the patients were 1.1,1.8 and 2.4 mg/L, respectively. The values of BIS and CSI at LVC in 5%, 50% and 95% of the patients were 79.2, 69.2 and 59.2; 74.9, 65.9 and 56.8, respectively. The predicted effect-site concentrations of propofol at LOC in 5%, 50% and 95% of the patients were 1.5, 2.5 and 3.4 mg/L, respectively. At LOC, the values of BIS and CSI in 5%, 50% and 95% of the patient were 73.6, 57.1 and 40.6; 65.2, 54.8 and 44.3, respectively. CONCLUSION: During target-controlled infusion of propofol, LVC and LOC occur within a definite range of predicted effect-site concentrations. There is the good linearity between BIS, CSI and the predicted effect-site concentrations of propofol. CSI may be more useful than BIS in predicting LVC and LOC.