Daunderer M, Schwender D
Klinik für Anästhesiologie, Ludwig-Maximilians-Universität München, Klinikum Grosshadern, Marchioninistrasse 15, 81377 München.
Anaesthesist. 2001 Apr;50(4):231-41. doi: 10.1007/s001010050997.
Inapparent adverse intraoperative wakefulness is still a relevant problem in modern anaesthetic routine. It can be associated with serious negative effects on the postoperative recovery of the patients. Several different procedures have been developed to monitor and therefore avoid intraoperative situations of wakefulness during general anaesthesia. The most promising methods are the PRST-score, calculated from changes in the blood pressure, heart rate, sweating and tear production, the so-called isolated forearm technique, spontaneous EEG and its derived parameters such as spectral edge frequencies or BIS and finally mid-latency auditory evoked potentials. The observation of clinical autonomic signs, even including the calculation of the PRST-score does not seem to be valid enough to indicate or predict intraoperative wakefulness. The isolated forearm technique can be regarded as the most reliable tool to detect intraoperative wakefulness, but it can only be applied for a very limited period of time. The processed EEG with the median frequency, spectral edge frequency or bispectral index are important scientific tools to quantify central anaesthetic effects especially to develop pharmacodynamic-pharmacokinetic models of anaesthetic action. But they seem to be less suitable to indicate situations of intraoperative wakefulness or awareness. The mid-latency auditory evoked potentials are depressed dose-dependently by a series of anaesthetic agents, which correlate with the occurrence of situations of intraoperative wakefulness and awareness. There is a hierarchical correlation between certain values of the MLAEP and intraoperative wakefulness defined by purposeful movements, amnesic awareness with only implicit recall and conscious awareness with explicit recall. For some of the most commonly used anaesthetics reasonable threshold values of the MLAEP for the different states of consciousness have already been determined. Future studies in broad patient populations with all of the different routinely used anesthetics and procedures will have to finally identify the importance of the recording of mid-latency auditory evoked potentials as a routine method to assess the depth of anaesthesia.
术中隐匿性不良觉醒在现代麻醉常规中仍是一个相关问题。它可能对患者术后恢复产生严重负面影响。已经开发了几种不同的方法来监测并因此避免全身麻醉期间的术中觉醒情况。最有前景的方法是PRST评分，它由血压、心率、出汗和泪液分泌的变化计算得出；所谓的孤立前臂技术；自发脑电图及其衍生参数，如频谱边缘频率或脑电双频指数（BIS）；最后是中潜伏期听觉诱发电位。观察临床自主神经体征，甚至包括PRST评分的计算，似乎都不足以有效指示或预测术中觉醒。孤立前臂技术可被视为检测术中觉醒最可靠的工具，但它只能在非常有限的时间段内应用。经处理的脑电图，包括中频、频谱边缘频率或双谱指数，是量化中枢麻醉效果的重要科学工具，特别是用于建立麻醉作用的药效学-药代动力学模型。但它们似乎不太适合指示术中觉醒或知晓的情况。中潜伏期听觉诱发电位会被一系列麻醉剂剂量依赖性地抑制，这与术中觉醒和知晓情况的发生相关。中潜伏期听觉诱发电位的某些值与由有目的运动定义的术中觉醒、仅隐性回忆的遗忘性知晓和有明确回忆的有意识知晓之间存在分级相关性。对于一些最常用的麻醉剂，已经确定了不同意识状态下中潜伏期听觉诱发电位的合理阈值。未来针对广泛患者群体，使用所有不同常规麻醉剂和方法的研究，将最终确定记录中潜伏期听觉诱发电位作为评估麻醉深度常规方法的重要性。
