脑电样本熵与双频指数在异丙酚麻醉诱导期间对镇静深度评价的相关性研究

目的：评价异丙酚静脉麻醉诱导过程中脑电样本熵（SampEn）和双频指数（BIS）与异丙酚血药浓度及患者镇静深度的相关性。方法：40例ASAⅠ～Ⅱ,年龄18～65岁拟采用全身麻醉行择期肿瘤手术的患者。异丙酚麻醉诱导初始靶控浓度0.5μg/mL,随后每间隔1 min递增0.5μg/mL,直至意识消失。每隔20 s行改良镇静/警觉评分（MOAA/S）,并实时记录原始脑电波及BIS值,通过原始脑电波线下进行样本熵的计算。计算决定系数（R2）和预测概率（PK）比较SampEn和BIS与异丙酚血药浓度及镇静深度的相关性。结果：随着异丙酚靶控浓度的递增,SampEn与BIS值均相关性递减,其相关系数分别为R2-SampEn=0.91±0.15、R2-BIS=0.86±0.08,两者无显著性差异（P〉0.05）;SampEn与BIS可有效区分MOAA/S刻度上5～2评分（P〈0.05）,且SampEn在1～0的评分变化中有统计学意义（P〈0.05）;SampEn与BIS基于改良镇静/警觉评分对意识深度的预测概率（PK）分别为0.94±0.01、0.92±0.01,两者间PK无显著性差异（P〉0.05）。结论：SampEn在反映异丙酚药效变化时表现出等同于BIS的良好相关性,且能有效用于麻醉镇静深度的预测。

Comparative evaluation of sample entropy and bispectral index as a monitor of sedation depth during anesthesia induction with propofol

Objective: To evaluate the relationship of sample entropy(SampEn) and bispectral index(BIS) with sedation depth during propofol anesthetic induction.Methods:40 patients aged from 18～65years(ASA I or II),scheduled for elective surgery with cancer.During the anesthesia induction,sedation level was assessed by Modified Observer’s Assessment of Alertness/Sedation scale(MOAA/S) every 20 s during stepwise increase(target-controlled infusion,0.5 μg/mL) of propofol until the patient lost consciousness,every propofol concentration level was maintained over 1 min,meanwhile recording the raw electroencephalogram(EEG) and the value of BIS.The SampEn was calculated off-line from the recorded raw EEG data.The performance of SampEn and BIS as index of propofol concentration and sedation levels was compared by correlation coefficient(R2)and prediction probability(PK).Results: The correlation coefficient between SampEn and BIS with propofol plasma concentration were R2-SampEn =0.91±0.15 and R2-BIS=0.86±0.08,respectively.Both SampEn and BIS were able to distinguish between MOAA/S levels 5 to 2(P<0.05),whereas at deeper anesthesia,SampEn showed significance difference between MOAA/S levels 0 and 1(P<0.05).The prediction probability(PK) values of MOAA/S for SampEn and BIS were 0.94±0.01 and 0.92±0.01,respectively.Conclusion: The SampEn has the good correlation with propofol dose-response,which is similar with the BIS performance.And the SampEn could predict well with clinical assessment of anesthesia sedation depth.