Response of Parameters of EEG on the Anesthetic Depth and the Movement in Human<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

陈  雷
中国医学科学院阜外心血管病医院麻醉科，北京100037
Lei Chen, MD, PhD
Department of Anesthesiology, Cardiovascular Institute and Fuwai Hospital, Chinese Academy of Medical Sciences, Beijing 100037, China

ABSTRACT

Objective: To observe the response of parameters of EEG on the anesthesia and the movement.
Methods: 33 unpremedicated patients with congenital heart disease were divided into two groups: Group A (unmoved, n = 17) and Group B (moved, n = 16). All patients were monitored with EEG after entering operating room and induced with isoflurane and 80% N₂O in oxygen. After tracheal intubation, anesthesia was maintained with isoflurane only until skin incision. End-tidal isoflurane were maintained at stable concentrations (1 MAC) for at least 15 min prior to the skin incision. 
Results: 95% of spectral edge frequency (95% SEF) and percentage of total power in alpha band were significant higher in the patients in Group A than those in Group B (p < 0.01) when the skin incision. 
Conclusion: 95% SEF and percentage of total power in alpha band might be useful in predicting movement responses to surgical skin incision.
Key words: Electroencephalogram, 95% of spectral edge frequency,  percent of total power in alpha band; movement;  minimum alveolar concentration; congenital heart disease

　　众所周知，脑电图（electroencephalogram，EEG）是监测人脑活动的重要手段之一。在麻醉状态下，人脑活动趋于减弱，脑电活动也趋于减少。目前，利用EEG等手段监测麻醉水平日益普遍，临床上双频谱指数（bispectral index，BIS）已逐渐成为评估麻醉深度的重要指标之一。本实验是在使用BIS监测心脏手术患者麻醉水平的过程中，观察到其它EEG指标对麻醉深度有明显的指导作用。

资料和方法<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

1．左向右分流先天性心脏病患者33例，在全麻低温体外循环下行房（室）间隔修补术。
2．患者进入手术室后，联接各种常规监测（SpO₂、ECG、血压等）以及EEG。从麻醉诱导前开始持续监测患者的BIS、95%边缘频率（95% spectral edge frequency, SEF）,中间频率（median frequency, MF）以及δ波、θ波、α波和β波所占的能量百分比。
3． 所有患者不给予术前用药，以异氟醚和80%氧化亚氮吸入行麻醉诱导，经静脉给予琥珀胆碱1mg/kg后行气管插管，然后持续吸入异氟醚，维持呼出气异氟醚浓度稳定在预计的MAC值(1MAC)直至切皮，其间不给予其它肌肉松弛药。
4.  数据分析用t检验，p值小于0.05为有显著性差异．

结　果

根据患者是否出现体动分组，33例患者中出现体动的有17例，为A组，未出现体动的16例，为B组。两组患者在性别、年龄和体重等方面无显著性差异。A组患者的α波比重和95%SEF分别为6.4和8.6，均明显高于B组患者的α波比重和95%SEF（分别为3.2和6.7）。这两项指标（表1）在两组间有非常显著的差异（p < 0.01）。

讨　论

麻醉深度的监测和评估历来是困扰麻醉医师的难题之一。尽管许多学者在脑电生理^{[1, 2]}、应激反应、呼吸循环状态^[3]等方面的监测进行了大量深入的研究，但到目前为止临床上还是对麻醉深度缺乏实用有效的监测手段，除了BIS外，95%SEF也是目前临床上比较常用的监测指标之一^[4-6]。本实验中，在手术开始前，使呼出气异氟醚的浓度持续稳定在1MAC值至少15分钟，从而在理论上保证了所有患者在切皮时麻醉深度相同。但是由于MAC值的特点，本实验中有半数的患者出现了体动，正是由于这一点，使我们可以观察在“相同的麻醉深度”情况下，EEG参数对患者体动的反应。有文献报道，虽然BIS和95%SEF可以监测麻醉深度，但都不能很好地指明麻醉深度是否已足够防止出现体动^[7]。我们的实验结果表明: 95%SEF和α波比重可预示患者对切皮出现的体动反应，但BIS并没有对患者体动表现出明显的变化。虽然我们的实验表现出了α波比重的变化，但其对麻醉深度的监测作用目前尚未见报道。这些都有待于我们进一步研究。

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　　陈雷，1962年生。现任中国协和医科大学硕士研究生导师，阜外心血管病医院麻醉科副主任医师，副主任。获卫生部科技进步奖，发表论文30篇，参加编写专著多部，本刊编委。