脑电熵在麻醉深度监测中的应用现状

脑电熵是对脑电信号不规则性、无序性、不可预知性的量化指标.脑电熵(近似熵、Shannon 熵、谱熵)是临床监测麻醉深度的良好指标.Dutex-Ohmeda公司推出的EntropyTM模块是时一域平衡谱熵,它引入了状态熵(state entropy,SE)与反应熵(response entropy.RE)两个参数指标.状态熵,只是覆盖了脑电图(electroencephalogram,EEG)频率范围(0.8 Hz-32 Hz),因此主要反映大脑皮层状态;反应熵则覆盖了包括EEG 和肌电图(electromyogram,EMG)在内的频率范围(0.8 Hz-47 Hz),其数值受肌电活动的影响.在镇静监测方面,EntropyTM模块与脑电双频指数(bispectral index,BIS)监护仪对镇静水平的监测能力相似;在镇痛监测方面,反应熵可能对确定麻醉过浅及疼痛刺激所致的患者麻醉苏醒有意义.脑电熵像其他数量化脑电图一样,仍源于脑电,只是计算方法不同,因此,临床仍期待新型麻醉深度监测方法的问世.

Application of entropy of EEG in monitoring anesthetic depth

Entropy of EEG is the quantified parameter of irregularity or unpredictability of EEG.Entropy of EEG(ap-proximate entropy.Shannon entropy,spectral entropy)is a good measurement for anesthetic depth.The Datex Ohmeda En-tropyTM module is a commercial available device called-time requency balanced spectral entropy,including two entropy indica-tors:state entropy (SE) and response entropy (RE).State entropy is computed over the frequency range from 0.8 Hz to 32Hz.It includes the EEG.dominant part of the spectrum,and therefore primarily reflects the cortical state of the patient.Re-sponse entropy is computed over a frequency range from 0.8 Hz to 47 Hz.It includes both the EEG-dominant and EMG-dom-inant part of the spectrum.EntropyTM module has similar ability in hypnosis monitoring with BIS monitor.However,response entropy may be useful to identify inadequate anesthesia and patient arousal during painful stimuli.Entropy of EEG is derived from electroencephalogram like other qEEG.The differences are their own algorithms.Therefore,new predictors of anesthetic depth are called in clinical practice.