熵指数监测在全凭静脉麻醉诱导期中的应用

Applied study of spectral entropy as an electroencephalographic measure during inducing period of propofol anaesthesia

目的：研究全凭静脉麻醉中新型麻醉深度监测仪熵指数在全麻诱导期的应用并与双频谱指数比较。方法：ASAI～Ⅱ级择期腹部手术患者20例，人室后常规监测，然后异丙酚、维库溴铵、芬太尼快诱导气管插管，持续泵人异丙酚，间断推注维库溴铵和芬太尼维持麻醉。采用自身对照试验设计，对每例患者同时行熵指数（包括反应熵和状态熵）和双频谱指数监测，以睫毛反射消失、大声呼名和轻推肩膀无反应作为意识消失时点，于人室，睫毛反射消失前60s、前45s、前30s，睫毛反射消失即刻，后30s、后45s、后60s记录数据。结果：反应熵、状态熵和双频谱指数预测全麻诱导期意识消失的概率分别为0．9386、0．9312和0．9149，三者没有统计学差异（P〉0．05），预测概率与相应的脑电指数的Logistic回归方程分别为：抚R／（1．Pk）=20．724-0．267x、InPk／（1-Pk）=19．278-0．26x和抚R／（1-P＆）=23．865-0．348x；意识消失后反应熵和状态熵值继续下降并趋向等值23．4±6．5和23．9±6．4，最低值可达11～18，同时脑电波形出现抑制模式，而此时双频谱指数却无明显变化，维持于48．3±3．5之间。结论：在判断从有意识到无意识的转变上熵指数似乎比双频谱指数更灵敏，并且可以反映爆发抑制，监测麻醉过深。

Objective： To evaluate the application of spectral entropy including response entropy （RE） and state entropy （SE） as a new electroencephalographic measure during inducing period of general anaesthesia and compare it with bispectTal index （ BIS ）. Methods： Twenty ASA I - Ⅱ patients undergoing elective abdominal surgery were studied. Anaesthesia was induced with prepofol, vecuronium and fentanyl iv. After intubation anaesthesia was maintained with propofol infusion and intermittent injection of vecuronium and fentanyl Applying self-control design, every patient was monitered with spectral entropy and BIS simutaneously. Loss of eyelash reflex together with no responses to verbal commands and slight prodding or shaking were considered to be unconscious, then we recorded the data at following time： baseline values, 60s before loss of eyelash reflex. 45s before, 30s before, loss of eyelash reflex, 30s after loss of eyelash reflex, 45s after, 60s after. Results： Prediction probabilities of RE, SE and BIS for loss of consciousness were 0.938 6, 0.931 2 and 0.914 9 respectively, and no statistic differences between them （P 〉0.05 ） ; Furthermore, Logistic regressive equations of prediction probability and spectral entropy or BIS were calculated out as In Pk/（1-Pk） = 20.724-0.267x, In Pk/（1-Pk） = 19.278-0.26x and In Pk（1-Pk） = 23.865-0.348x respectively. After loss of , RE and SE kept going down to 23.4 ± 6.5 and 23.9 ± 6.4 and reached the lowest values of 11-18, meanwhile EEG waveform showed suppressed pattern, that meant burst suppression happened. But we couldn＇t see the similar changes in BIS. Conclusions： Entropy index seems to be better than BIS in predicting loss of consciousness, moreover it can indicate burst suppression.