Intraoperative monitoring of depth of anesthesia by automated EMG-analysis

观察到脑电图活动与麻醉和镇痛药物浓度之间的相关性，导致了处理脑电图单参数的发展。有了这些，BIS（双谱指数）已经得到了广泛的应用。然而，关于这种方法一直存在争议。虽然在b -aware试验中已证明术中意识显著降低，但这些结果在b -unaware试验中不可重复。我们的研究小组已经对术中处理后的颅神经肌电图数据进行了超过10年的自动化分析。在开发和测试这些技术的外科手术过程中，观察到大量肌电图活动的自发发作，主要发生在喉咙、舌头和咽部的肌肉中。在这些发作开始几分钟后，几次患者会出现相当大的运动。因此，假设这些肌肉的激活表明保护性反射的开始，并且由此产生的肌电活动可能作为警告参数。进行了一项初步研究，并对喉咙、舌头和咽部肌肉的肌电图进行了量化。与此同时，国际清算银行也接受了评估。根据这些数据，比较拔管与监测参数（BIS和EMG）明显上升的时间间隔。BIS的中位时间间隔为5.9min，拔管前肌电参数中位上升12.3min。结果，经mann - whitney检验，肌电参数的预警间隔明显延长（p = 0.026）。本研究和当代文献的观察结果表明，这些发现原则上可以应用于面神经肌电图，在日常实践中可以用更简单的方法进行评估。计划项目的目标是开发和评估一个全自动定量系统，该系统依赖于面部神经肌电图作为指示唤醒反应和等待患者运动的警告参数。为了对该系统进行评估，由此产生的警告参数将与BIS和以下附加参数相关联：PRST-score b。)镇痛深度（ANI-monitor）镇痛药理学深度：利用阿片类药物计算效应室浓度d)催眠的药理学深度：计算异丙酚的效应室浓度。在本项目的后续研究中，这些结果可用于前瞻性评估在不同效应室阿片类药物浓度下，持续手术刺激下肌电参数的变化。

The observation of a correlation between EEG-activity and concentrations of anaesthetic and analgetic agents led to the development of processed EEG-monoparameters. Amount these, the BIS (bispectral index) has come to widespread use. However, there is ongoing controversy regarding this method. While a significant reduction of intraoperative awareness has been demonstrated in the B-aware-trial, these results were not reproducible in the B-unaware-trial. Our group has investigated automated analysis of processed intraoperative cranial nerve EMG data for more than 10 years. During surgical procedures in which these techniques were developed and tested, spontaneous episodes of massive EMG-activity, mainly in the muscles of throat, tongue and pharynx, have been observed. Minutes after the beginning of these episodes, considerable patient movement would occur on several occasions. Thus, it was hypothesized that the activation of these muscles indicates the initiation of protective reflexes, and that the resulting EMG-activity might serve as a warning parameter. A pilot study was conducted, and EMG from the muscles of throat, tongue and pharynx was quantified. In a parallel fashion, the BIS was assessed. With these data, the time interval between extubation and clear rise of the monitoring parameters (BIS and EMG) was compared. A median time interval of 5.9min was found for the BIS, while the EMG-parameter would rise 12.3min before extubation in median. As a result, a significantly longer warning-intervall was calculated for the EMG-parameter with the Mann-Whitney-test (p = 0.026). Observations made during this study and contemporary literature suggest that these findings should in principle be transferable to facial nerve EMG, which may be assessed in a much more simple way in routine practice. The goal of the planned project is the development and evaluation of a fully automated quantitative system, which relies on facial nerve EMG as a warning parameter indicating arousal reactions and pending patient movement. In order to evaluate this system, the resulting warning parameter is to be correlated with the BIS and the following additional parameters: a.) PRST-score b.) Depth of analgesia (ANI-monitor) c.) Pharmacological depth of analgesia: Calculated effect compartment concentration for utilized opiate d.) Pharmacological depth of hypnosis: Calculated effect compartment concentration for Propofol. In succession of this project, these results may be used for a prospective evaluation of variations in the EMG-parameter with constant surgical stimulus under varying effect compartment concentrations of opiates.