Katoh T, Suzuki A, Ikeda K
Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Japan.
Anesthesiology. 1998 Mar;88(3):642-50. doi: 10.1097/00000542-199803000-00014.
The electroencephalogram (EEG) has been evaluated as a tool for measuring depth of anesthesia, but the use of the EEG monitoring is still controversial. The current study was designed to evaluate the accuracy of three EEG parameters and anesthetic concentration for predicting depth of sedation and anesthesia during sevoflurane anesthesia
One low and one high equilibrated concentration ranging from 0.2-1.8% were assigned randomly and administered consecutively to 69 patients. The bispectral index (BIS; version 3.2), 95% spectral edge frequency (SEF), and median power frequency (MPF) were obtained from a bipolar frontomastoid (Fp1-A1, Fp2-A2) montage using an EEG monitor. Sedation was assessed using the responsiveness portion of the observer's assessment of alertness-sedation scale. In the second phase of the study, the 47 patients who were scheduled to have skin incisions were observed for purposeful movement in response to skin incision at sevoflurane concentrations between 1.6% and 2.4%. The relation among BIS, 95% SEF, MPF, sevoflurane concentration, sedation score, and movement or no movement after skin incision, was determined. Prediction probability values for EEG parameters and sevoflurane concentration to predict depth of sedation and anesthesia were also calculated.
The BIS and sevoflurane concentration correlated closely with the sedation score. Both 95% SEF and MPF changed significantly but biphasically with increasing sedation. The prediction probability values for BIS and sevoflurane concentration were 0.966 and 0.945, respectively, indicating a high predictive performance for depth of sedation. No EEG parameters predicted movement after skin incision better than chance alone.
Parameters derived from EEG, such as BIS, and 95% SEF are reliable guides to the depth of sedation, but not to the adequacy of anesthesia level for preventing movement during sevoflurane anesthesia.
脑电图（EEG）已被评估为测量麻醉深度的一种工具，但EEG监测的应用仍存在争议。本研究旨在评估三种EEG参数和麻醉浓度在七氟醚麻醉期间预测镇静和麻醉深度的准确性。
将0.2%至1.8%范围内的一种低平衡浓度和一种高平衡浓度随机分配并连续给予69例患者。使用EEG监测仪从双极额乳突（Fp1-A1，Fp2-A2）导联获取脑电双频指数（BIS；版本3.2）、95%频谱边缘频率（SEF）和中位功率频率（MPF）。使用观察者警觉-镇静评分量表的反应部分评估镇静程度。在研究的第二阶段，观察47例计划进行皮肤切开的患者在七氟醚浓度为1.6%至2.4%时对皮肤切开的有目的运动。确定BIS、95%SEF、MPF、七氟醚浓度、镇静评分以及皮肤切开后运动或无运动之间的关系。还计算了EEG参数和七氟醚浓度预测镇静和麻醉深度的预测概率值。
BIS和七氟醚浓度与镇静评分密切相关。随着镇静程度增加，95%SEF和MPF均发生显著但呈双相性的变化。BIS和七氟醚浓度的预测概率值分别为0.966和0.945，表明对镇静深度具有较高的预测性能。没有EEG参数对皮肤切开后运动的预测优于单纯靠概率。
源自EEG的参数，如BIS和95%SEF，是镇静深度的可靠指标，但对于七氟醚麻醉期间预防运动的麻醉水平是否足够并非可靠指标。
