Background. There is an increasing concern of awareness and recall during general anesthesia for both the patient and the anesthetist. The bispectral index (BIS) is used to assess the level of sedation and depth of anesthesia and detect consciousness in different anesthetic drugs. Middle-latency auditory evoked potentials (AEPs) also quantify action of anesthetic drugs and detect the transition from consciousness to unconsciousness. We aim to compare the sensitivity and specificity between BIS and AEP in predicting unconsciousness in inhalational sevoflurane anesthesia and intravenous propofol anesthesia. Methods. Totally, 40 patients were randomly allocated into two groups: propofol or sevoflurane group. In the propofol group, anesthesia was induced with target-controlled infusion propofol. In the sevoflurane group, anesthesia was induced by increasing concentrations of sevoflurane. There were 3 end points during induction: sedation, unconsciousness, and anesthesia. Target and effect-site concentrations of propofol, end-tidal concentration of sevoflurane, and BIS and AEP were recorded at each stage. Results. We obtained good EC50 with both monitors, at which there is a 50% chance that the patient has reached the end point, but the index variation was affected by the anesthetic technique. Propofol had higher correlations with stage of anesthesia, BIS, and AEP than sevoflurane. BIS had higher correlations with depth of anesthesia than AEP, but we did not find an anesthetic depth monitor that had high sensitivity and specificity and is not affected by the anesthetic technique. Conclusions. The prediction powers of BIS and AEP do not seem as good as some papers mentioned.

中文翻译：

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BIS和AEP在预测全麻无意识中的敏感性和特异性的交叉比较

背景。在全身麻醉期间，对于患者和麻醉师的意识和召回率越来越高。双光谱指数（BIS）用于评估镇静水平和麻醉深度，并检测不同麻醉药物的意识。中潜伏期听觉诱发电位（AEP）还可以量化麻醉药的作用并检测从意识到无意识的转变。我们旨在比较BIS和AEP之间的敏感性和特异性，以预测吸入性七氟醚麻醉和异丙酚麻醉中的意识丧失。方法。共有40例患者随机分为两组：丙泊酚或七氟醚组。在丙泊酚组中，通过靶控输注丙泊酚诱导麻醉。在七氟醚组中，通过增加七氟醚的浓度来诱导麻醉。诱导过程中有3个终点：镇静，神志不清和麻醉。在每个阶段记录异丙酚的靶点和作用部位浓度，七氟醚的潮气末浓度以及BIS和AEP。结果。我们在两台监护仪上均获得了良好的EC50，在这种情况下，患者达到终点的机会为50％，但是麻醉技术会影响指数的变化。丙泊酚与麻醉，BIS和AEP的相关性高于七氟醚。BIS与麻醉深度的相关性高于AEP，但我们没有发现具有高灵敏度和特异性且不受麻醉技术影响的麻醉深度监测仪。结论。BIS和AEP的预测能力似乎不如某些论文所述。