脑电双频指数与听觉诱发电位指数用于麻醉深度监测的临床评价

随着经济的发展，脑电（EEG）监测有望成为临床麻醉、急诊及重症监护病房的常规监测手段，其中研究较多的脑电双频指数（BIS）和听觉诱发电位指数（AEPindex，AAI）已在麻醉诱导、维持、恢复等方面显示出优势。本文旨在就近年来BIS和AAI应用于麻醉实践中的优点及不足作一综述。     

麻醉深度监测新进展:双频指数

全身麻醉深度的监测有许多方法.但至今尚无一种方法能直观、准确、动态地反映麻醉深度.以往曾通过监测血流动力学的变化来间接反映麻醉深度,也有用原始脑电信号、听觉诱发电位、肌电图、食管收缩能力变化、瞳孔反射以及采用多种变异综合分析,应用微机的多因素逻辑学方程分析等.但一直没有直接方法测定麻醉药对中枢神经系统的作用.     

全身麻醉深度监测研究的新进展

麻醉深度监测是临床麻醉工作的重要任务之一。在全身麻醉时，意识的传统体征(血压、心率、呼吸和瞳孔等)已不能准确反映麻醉深度。目前，其研究重点集中在脑电活动方面，如脑电双频指数、听觉诱发电位指数等，虽然显现出一定的优势，但也存在着不少的缺陷。新近研发的Narcotrend，人工神经网络、患者状态指数以及唾液中的cGMP含量测定，使麻醉深度监测的研究更加深入，现就目前的研究进展予以综述。     

BIS和AAI用于监测镇静深度的研究现状

椎管内阻滞是一种常用的麻醉方法,期间往往需要适当的镇静治疗;全麻需要监测意识转换、术中知晓和预测苏醒.临床上常用警觉/镇静评估法(observer's assessment of alertness/sedation,OAA/S)进行镇静程度的评分,而术中频繁的唤醒患者来判断镇静程度是不现实的.20世纪90年代以来,多种神经功能监测指标相继引入临床麻醉领域,用于镇静和苏醒判断的检测,其中脑电双频指数(bispectrial index,BIS)和听觉诱发电位指数(auditory evoked potential index,AEPindex)最具代表性,其中又以采用ARX模式提取得出的听觉诱发电位指数(A-line ARX Index,AAI)最为常用.BIS和AAI先后获得FDA认证,应用前景极为乐观,二者作用机理不同,对镇静深度监测各有特点,本文比较综述二者在监测镇静深度和预测苏醒的作用.     

双频指数和听觉诱发电位在监测麻醉深度中的价值

目的　评估脑电双频指数 (BIS)和中潜伏期听觉诱发电位 (MLAEP)在监测麻醉深度中的价值。方法　 2 1例择期手术患者随机分为Ⅰ组 (对照组 ,n =11)和Ⅱ组 (咪唑安定组 ,n =10 ) ,输入复方乳酸钠液 10ml/kg后 ,以 0 4mg·kg-1·min-1的速度静脉推注丙泊酚 2mg/kg ,在诱导第 4分钟注入维库溴铵 0 1mg/kg、芬太尼 2 μg/kg ,Ⅱ组同时注入咪唑安定 0 0 4mg/kg。记录OAA/S镇静评分、收缩压、舒张压、心率、BIS和反映MLAEP的ARX指数 (ARX Index ,AAI)的基础值 ,以及诱导插管时每分钟的数值。结果　 (1)AAI反应时间较BIS显著缩短 (P <0 0 5 ) ;(2 )OAA/S镇静评分与BIS、AAI显著相关 (r =0 86 0 2、0 85 5 0 ,P <0 0 1) ;(3)Ⅱ组注入咪唑安定后 1分钟 ,AAI较Ⅰ组显著下降 (P <0 0 5 ) ;2分钟后 ,BIS较Ⅰ组显著下降 (P =0 0 0 1) ;(4)Ⅰ组的插管反应大于Ⅱ组 ,插管即刻AAI差异显著 (P =0 0 1) ,插管后 1分钟BIS差异显著 (P <0 0 5 ) ;Ⅱ组在插管前后AAI和BIS均无显著差异。结论　 (1)AAI和BIS均能反映镇静程度和插管反应 ,但AAI反应更快 ,趋于实时监测 ;(2 )联合应用咪唑安定诱导可以抑制插管反应     

脑电双频指数在麻醉深度监测中的研究进展

现就脑电双频指数(bispectral index，BIS)与麻醉药物浓度及镇静深度的相关性研究，阿片类药物及麻醉过程中常用的非麻醉药物对BIS的影响进行综述，并与听觉诱发电位指数进行比较。     

脑电熵在麻醉深度监测中的意义

随着肌松药和镇痛药等药物的联合应用,现代全身麻醉的深度、患者的意识状态常常被掩盖或难以判断.以往的传统体征(血压、心率、呼吸和瞳孔等)已不能准确地反映麻醉深度.目前,有关研究重点集中在脑电活动方面,如脑电双频指数(bispectral index,BIS)、脑电熵(entropy)、听觉诱发电位等.现就entropy在麻醉深度监测中的意义及其研究进展作一综述,并与脑电双频指数进行比较.     

心率变异性Poincare散点图分析与BIS对麻醉深度监测的相关性研究

目的 观察全身麻醉时心率变异性分析中散点图分析和脑电双频指数(BIS)的变化,探讨散点图分析和BIS在监测麻醉深度时的相关性.方法 选择ASA Ⅰ或Ⅱ级择期手术患者28例,测定手术前一天(T1)、麻醉诱导前(T2)、诱导插管(T3)、手术开始1h(T4)、苏醒时(T5)、术后1d (T6)6个时点各5 min的HR、MAP、散点图的短轴(SD1)、长轴(SD2)的变化以及T2～T5时BIS变化.结果 与T1时比较,T6时MAP、SD2明显下降(P＜0.05).与T2时比较,T3时HR明显增快、MAP、SD2明显升高(P＜0.01);T4、T5时MAP、SD2明显下降(P＜0.05或P＜0.01);T3～T5时BIS、SD1明显下降(P＜0.01).结论 心率变异性非线性分析SD1能描述围术期心脏自主神经功能状态的变化,与反应麻醉镇静程度的BIS有很好的相关性.     

BIS和AEPI监测镇静深度的评价

目的比较脑电双频指数（BIS）和听觉诱发电位指数（AEPI）在丙酚靶控镇静深度的临床价值.方法45例腰-硬联合麻醉术中需丙泊酚镇静病人,ASA I级,腰麻平面确定后开始丙泊酚靶控输注镇静.结果（1）丙泊酚镇静期BIS、AEPI逐渐降低,苏醒期逐渐升高（P＜0.01）,而AEPI则在意识转换过程中变化更敏感（P＜0.01）.（2）在丙泊酚镇静期和苏醒期BIS、AEPI与丙泊酚EC密切相关.（3）在丙泊酚镇静期,联合监测当BIS≤63和AEPI≤30时敏感度即可达100%.结论BIS和AEPI是监测麻醉镇静深度的良好指标,BIS和AEPI联合监测提高了诊断的敏感度.     

中潜伏期听觉诱发电位在麻醉深度监测中的应用

术中知晓在全麻手术中日益受到重视,研究发现中潜伏期听觉诱发电位（ＭＬＡＥＰ）的潜伏期和波幅与麻醉药呈剂量依赖性抑制。本文综述了ＭＬＡＥＰ在麻醉深度监测中的应用。     

The AAI index,the BIS index and end-tidal concentration during wash in and wash out of sevoflurane

The bispectral index (BIS), auditory evoked potential index (AAI) and the end-tidal sevoflurane concentration were studied during induction and emergence in 10 ASA I-II patients. Both during 'wash-in' and 'wash-out' of sevoflurane, the AAI and BIS indices show huge variability and an overlap of indices between awake and not responding to command. This was the most pronounced during induction and the range of values was larger for the AAI index as compared with the BIS index. Mean (range) BIS was 85 (73-98) and 48 (10-83) awake and unconscious, respectively, and mean AAI index was 71 (43-99) and 21 (4-85), respectively. This study demonstrates the difficulties of using processed EEG variables in real time in a clinical situation of non-steady state pharmacodynamics.     

听觉诱发电位指数和脑电指数用于监测全麻深度的比较性研究

目的　比较听觉诱发电位指数 (AAI) ,双频谱指数 (BIS)在监测全麻诱导及恢复期的准确性。方法　ASAⅠ -Ⅱ级听力正常的择期腹部手术病人 ,随机分为Ⅰ组 (对照组n =15 )和Ⅱ组 (咪唑安定组 n =15 ) ,实施异丙酚 -异氟醚或异丙酚 -咪唑安定 -异氟醚复合麻醉 ,记录麻醉诱导及恢复期各时间点AAI、BIS、HRV及血液动力学参数 ,并研究AAI与其它指标的相关性。结果　 (1)AAI反应时间较BIS明显缩短。 (2 )OAA/S镇静评分与BIS、AAI显著相关 (r =0 .93 3、0 .5 3 3、P <0 .0 1)。 (3 )苏醒时 (对呼名有反应 )AAI、BIS的变化两组间差异无统计学意义。结论　AAI、BIS均能监测麻醉诱导及恢复期麻醉深度 ,AAI反应更快 ,趋于实时监测。     

心率变异性近似熵分析法与脑电双频谱指数间的相关性

目的:观察全身麻醉时心率变异性分析中近似熵分析法与脑电双频谱指数(BIS)在监测麻醉深度时的相关性。方法:对40例全身麻醉病人测定麻醉前(T1)、诱导插管(T2)、术中(T3)、苏醒(T4)4个时间点各5min的心率(HR)、平均动脉压(MAP)、脑电双频谱指数(BIS)和近似熵(ApEn)变化。结果:HR在T2、T3和T4均较T1值升高(P0.01～0.05)。MAP在T2时较T1值降低(P0.05),T3、T4较T1值升高(P0.05),而T4比T3明显升高(P0.01)。BIS值在麻醉后各时点均较T1值下降明显(P0.01),其中T4也较T1下降(P0.05),T3与T2时相比明显降低(P0.01),而T4较T3明显升高(P0.01)。近似熵值的T1值均大于其他各时点(P0.01～0.05),其T4较T3时点升高(P0.01),T3较T2时点降低(P0.05)。结论:作为心率变异性的非线性分析方法指标的近似熵分析法,能描述围术期心脏自主神经功能状态的变化,但其与BIS并无相关性。     

Sevoflurane requirements during ambulatory surgery: a clinical study with and without AEP-index guidance

BACKGROUND: Several monitors have been developed to measure anesthetic depth. The auditory evoked response uses an auditory signal to actively test the level of brain activity. The aim of the present study was to determine whether sevoflurane titration with A-line auditory guidance from the evoked potential monitor would reduce gas consumption and improve recovery times. METHODS: Patients (n=60, aged 18-65 years) undergoing elective knee arthroscopy were randomized to titrate the main anesthetic sevoflurane with O2:N2O (1:2), either clinically (30 patients) or in combination with a target auditory evoked potential index of 30+/-5 (30 patients) using the A-line monitor (version 1.4, Danmeter A/S; Odense, Denmark). Induction was supplemented with fentanyl, and randomized to 0.05, 0.10 and 0.15 mg immediately before propofol (10 in each group). Sevoflurane consumption and emergence times were the primary and secondary study end-points. RESULTS: Guidance from the A-line monitor did not reduce the sevoflurane consumption time or the emergence, regardless of the fentanyl dose. However, it did reduce the time from the recovery room to discharge eligibility (P<0.05). Sevoflurane consumption decreased inversely with the fentanyl dose (P<0.01), with no impact on emergence times. CONCLUSION: The auditory evoked potential index provided by the A-line monitor does not decrease sevoflurane consumption or emergence times for ambulatory knee arthroscopy.     

AEP-monitor/2 derived, composite auditory evoked potential index (AAI-1.6) and bispectral index as predictors of sevoflurane concentration in children

BACKGROUND: Level of anesthesia may be predicted with the auditory evoked potential or with passive processed electroencephalogram (EEG) parameters. Some previous reports suggest the passive EEG does not reliably predict level of anesthesia in infants. The AAI-1.6 is a relatively new index derived from the AEP/2 monitor. It combines auditory evoked potentials and passive EEG parameters into a single index. This study aimed to assess the AAI-1.6 as a predictor of level of anesthesia in infants and children. METHODS: Four infants aged less than 1 year, and five older children aged between 2 and 11 years were enrolled. They all had uniform sevoflurane anesthesia for cardiac catheterization. The AAI-1.6 and bispectral index (BIS) were recorded after achieving equilibrium at 1.5%, 2% and 2.5% sevoflurane, and immediately prior to awakening. The prediction coefficient (Pk) for BIS and AAI-1.6 was calculated and compared within each age group. RESULTS: The Pk for the AAI-1.6 was low in both 0-1 and 2-11 years age groups. In the 2-12 years group, the Pk for BIS was significantly higher than the Pk for the AAI-1.6 (Pk for BIS: 0.89, Pk for AAI-1.6: 0.53, P < 0.01). In contrast in the 0-1 year age group there was no evidence for a difference between the Pk for BIS and the Pk for the AAI-1.6 (Pk for BIS: 0.74, Pk for AAI-1.6: 0.53, P = 0.25). CONCLUSIONS: This preliminary study suggests AAI-1.6 is a poor predictor of sevoflurane concentration in infants and children.     

Anesthesia with Sevoflurane in Bariatric Surgery

Background: Sevoflurane is a good halogen agent for bariatric surgery anesthesia because of its physical and chemical characteristics and its repartition coefficient (blood/gas = 0.65). Method: From November 1997 to April 1998, 98 bariatric surgery procedures with sevoflurane anesthesia were done: 17 lipectomies, 71 vertical gastroplasties, and 10 biliopancreatic diversions in 71 women and 27 men, average age 30.3 ± 8.3 years, with body mass index 43.9 ± 5.7. The average operating time was 50 ± 15 minutes for vertical gastroplasty, 160 ± 20 minutes for biliopancreatic diversion, and 80 ± 12 minutes for lipectomy. The technique of anesthesia was as follows: preanesthesia with atropine sulfate 0.01 mg/kg (dosage refers to ideal weight), ranitidine 50 mg, fentanyl 0.1 mg, ketorolac 60 mg; induction with propofol 0.5-1 mg/kg, succinylcholine 1 mg/kg; orotracheal intubation; maintenance with O2-N2O 50%, sevoflurane 1% to 1.5%, actracurium 0.5 mg/kg (dosage refers to ideal weight); awakening and decurarization with atropine sulfate 1 mg and prostigmine 2 mg. Results: This method permitted correct control of the anesthesia, a quick awakening with a low incidence of nausea and vomiting, a prompt regain of physical and psychological functioning, an early discharge from the hospital, and a larger turnover of patients with lower costs. Conclusion: Sevoflurane balanced anesthesia seems to be the best anesthesiologic method for bariatric surgery.     

The relationship between bispectral index and endtidal concentration of sevoflurane during anesthesia and recovery in spontaneously ventilating children

BACKGROUND: Global inverse correlation between BIS (bispectral index) and depth of anesthesia using sevoflurane has been documented in children in several studies under experimental conditions and in steady-state conditions during mechanically controlled ventilation. Because sevoflurane mask anesthesia combined with a peripheral nerve block is widely used in children, we studied the relationship between BIS and endtidal concentration of sevoflurane (PE(sevo)) under these conditions during surgery and emergence. METHODS: In this prospective blinded study of 32 children, the relationship between BIS and PE(sevo) was studied during sevoflurane anesthesia via facemask combined with peripheral nerve block. The intraoperative phase was studied during steady-state conditions (fixed PE(sevo)) and the emergence phase was studied during fast alveolar washout (FAW). BIS and PE(sevo) data fitted using the E(max) model. Coefficients of variation of BIS and PE(sevo) during the two periods were compared. RESULTS: Fit was adequate with the simple E(max) model. Intraoperative variation in BIS was large (28.4%), and larger than at awakening (28.4% vs 8%). At awakening, BIS varied less than PE(sevo) (8% vs 28.5%). No difference was found between children younger and those older than 5 years. CONCLUSIONS: Caution is required for intraoperative titration based on BIS when spontaneous ventilation is maintained because of the wide variability compared with PE(sevo). During emergence using FAW, BIS varied significantly less than PE(sevo), but the clinical relevance of this point could be discussed during anesthesia without tracheal intubation.     

Comparison of BIS and AAI as measures of anaesthetic drug effect during desflurane-remifentanil anaesthesia

BACKGROUND: Autoregressive modelling with exogenous input of the middle-latency auditory evoked potential has been developed for monitoring of anaesthetic depth. This study was designed to investigate the dose-response relationship between endtidal desflurane concentrations and the Alaris Autoregressive Index (AAI, Alaris Medical, Hampshire, UK, version 1.4) or the bispectral index (Aspect Medical Systems, Newton, MA, USA, version XP). METHODS: Twenty-one patients scheduled for radical prostatectomy were investigated. After premedication and induction of anaesthesia with propofol und remifentanil all patients received atracurium and a remifentanil background infusion at a constant rate of 0.1 micro g kg(-1) min(-1). During dissection of the prostate, desflurane endtidal concentrations were varied between 3 and 9 vol%. Both AAI and BIS were determined and compared with the respective endtidal desflurane concentration. RESULTS: None of the patients showed a significant change of AAI values while changing the desflurane concentrations between 3 and 9 vol%. The dose-response of BIS values and desflurane concentrations was not uniform: two patients showed increasing BIS values with increasing desflurane concentrations, while in three patients BIS values remained unchanged. In 16 patients decreasing BIS values adequately reflected an increase in desflurane concentrations. CONCLUSION: Changes of desflurane concentrations during deep anaesthesia were adequately displayed only in 16 of 21 cases by BIS but in none of the cases by AAI monitoring.     

心率变异性复杂度分析和脑电双频谱指数在监测全身麻醉时的相关性

目的：观察全身麻醉时心率变异性分析中复杂度和脑电双频谱指数（BIS）的变化,探讨复杂度和BIS在监测麻醉深度时的相关性。方法：30例全身麻醉病人,测定麻醉前（T1）、诱导插管（T2）、术中（T3）、苏醒（T4）4个时间点各5min的心率（HR）、平均动脉压（MAP）、脑电双频谱指数（BIS）和复杂度变化。结果：HR在T2、T3和T4较T1值升高（P〈0.01或0.05）。MAP在T2时较T1值降低（P〈0.05）,T3和T4较T1值升高（P〈0.05）,而T3和T4相比变化较大（P〈0.01）。BIS值在各时点较T1值下降明显（P〈0.01）,其中T4较T1略下降（P〈0.05）,T3与T2时相比明显降低（P〈0.01）,而T4较T3明显升高（P〈0.01）。复杂度值的T1值均大于各个点（P〈0.01或0.05）,其T4较T2和T3时升高（P〈0.05）,T3较T2时升高（P〈0.05）。结论：作为心率变异性非线性指标的复杂度能描述围术期心脏自主神经功能状态的变化,但其与BIS并无相关性。