EEG ANALYSIS AS A MEANS OF MONITORING DEPTH OF PSYCHOSEDATION

我们根据氧化亚氮浓度或客观确定的镇静状态检查了各指标的变化，并在静脉输注地西泮或咪达唑仑后，证实了脑电图中位数频率和成分比根据脑电图功率谱计算的频段波动反映了镇静的深度。在研究的临床部分，我们评估了在精神镇静下进行牙科治疗期间上述指标的变化和患者的客观发现。结果显示，吸入20%-30%的氧化亚氮时，脑电图中位数频率为5- 6hz，这通常能起到最佳的镇静作用，而吸入40%的氧化亚氮时，脑电图中位数频率低于5 Hz，这会导致睡眠状态。另一方面，静脉注射地西泮或咪达唑仑时，中位脑电图频率由初始升高逐渐下降，镇静开始后趋于稳定。频带分量比显示，在吸入氮气后，a波和慢波分量增加，快波分量减少；相反，在苯二氮卓类衍生物中，观察到快波分量最初上升，随后在整个镇静状态期间a波分量增加。这表明，苯二氮卓类药物衍生物的初始中位脑电图频率上升是由于苯二氮卓类药物特有的快速波动。在本研究的临床部分，服用苯二氮卓类药物后，脑电图中位数频率也有所上升，但在镇静状态下，脑电图中位数频率保持稳定，在患者感到疼痛或镇静作用减弱时达到峰值。以上结果表明，脑电图中位数频率的变化反映了精神镇静的深度和疼痛引起的应激状态等。由此可见，脑电图中位数频率似乎是精神镇静深度的一个有用指标。

We examined changes in each of the indices according to nitrous oxide concentration or objectively determined sedation state, and after intravenous infusion of diazepam or midazolam, confirmed that the fluctuation of median EEG frequency and component ratios according to a frequency band computed from the EEG power spectrum reflected the depth of sedation. In the clinical component of the study, we assessed such changes in the above indices during dental treatment performed under the psychosedation and the patient's objective findings.The results showed a median EEG frequency of 5-6Hz for inhalation of 20%-30% nitrous oxide, which generally provides optimum sedation, versus one of less than 5 Hz for inhalation of 40% nitrous oxide, which induces a sleep state. With intraveno us diazepam or midazolam, on the other hand, median EEG frequency gradually declined after an initial increase, becoming stable after the onset of sedation. The frequency band component ratios showed an increase in the a-and slow-wave components and a decrease in the fast-wave component in response to nitrous inhalation : in contrast, with the benzodiazepine derivatives an initial rise in the fast component was observed, followed by an increase in the a-component throughout the duration of the sedated state. This suggests that the initial rise in median EEG frequency with benzodiazepine derivatives is due to a fast-ware unique to benzodiazepines.In the clinical component of the study, median EEG frequency also rose after administration of the benzodiazepine derivatives : however, frequency in the sedated state was stable, peaking whenever the patients experienced pain or the sedative effect weakened. The above findings imply that changes in median EEG frequency reflect depth of mental sedation and stress states due to pain, et c. It is concluded that median EEG frequency appears to be a useful index of the depth of psychsedation.