The detection of cerebral hypoperfusion with bispectral index monitoring during general anesthesia

We describe a patient in whom the bispectral index (BIS) decreased to 0 during surgery. A 42-yr-old man with chronic renal failure was scheduled to undergo construction of an arteriovenous shunt. He had a history of acute cerebral hemorrhage. An intracranial hematoma had been removed a month earlier with almost complete neurological recovery. He had uncontrolled hypertension. His systolic blood pressure was 180 mm Hg before anesthesia induction. Anesthesia was induced with 100 mg of propofol and 3% sevoflurane. After laryngeal mask insertion, anesthesia was maintained with nitrous oxide 60% in oxygen and sevoflurane. BIS decreased to near 0 on 2 occasions: after anesthesia induction and shortly after the start of the surgery. His systolic blood pressure decreased to 110 mm Hg and BIS increased when his blood pressure was increased to 130-140 mm Hg. The decrease in BIS was suspected to be the result of decreased cerebral blood flow. The systolic blood pressure of 110 mm Hg (mean blood pressure, 80 mm Hg) was probably less than the lower limit of autoregulation. Although BIS has some limitations as a cerebral monitor, it was useful for detecting possible cerebral hypoperfusion in this case.     

脑电双频谱指数监测在小儿全身麻醉中的应用

脑电双频谱指数（BIS）能准确、及时地反映大脑生理功能的变化。其在成人全身麻醉中有较大的应用价值，现就BIS监测的原理，在小儿麻醉中的应用、应用过程中的局限性以及应用前景等加以综述。     

脑电双频指数在全凭静脉麻醉中的作用

目的 评价脑电双频指数(BIS)监测对全凭静脉麻醉用药及苏醒质量的影响.方法 鼻内窥镜手术全凭静脉麻醉患者66例随机均分为BIS组(Ⅰ组)和常规组(Ⅱ组),均采用丙泊酚联合雷米芬太尼双通道靶控输注.记录术中麻醉药用量、睁眼时间、拔管时间、语言指令反应恢复时间、定向力恢复时间及术中知晓发生率.结果 Ⅰ组丙泊酚用量显著少于Ⅱ组(P<0.05),而且其睁眼时间、拔管时间、语言指令反应恢复时间、定向力恢复时间均明显短于Ⅱ组(P<0.05).两组均无术中知晓发生.结论 BIS监测可减少全凭静脉麻醉丙泊酚用量并改善麻醉苏醒质量.     

小波指数用于麻醉深度监测的研究

目的研究在靶控联合输注丙泊酚和雷米芬太尼时小波指数(wavelet index,WLI)监测麻醉深度的可行性。方法选择30例行腹腔镜胆囊切除或妇科腹腔镜手术的全麻患者。全麻诱导采用血浆浓度靶控输注丙泊酚,从1.5μg/ml开始,达到浓度后1min增加0.5μg/ml,最终达到4.0μg/ml,于切皮前5min开始靶控输注雷米芬太尼4.0ng/ml,至开始缝皮时停止靶控输注丙泊酚和雷米芬太尼。患者麻醉全程同时监测WLI和BIS值。结果随着诱导过程中靶控丙泊酚血浆浓度的增加,WLI和BIS值均呈下降趋势(P0.05),丙泊酚血浆靶浓度为0、1.5、4.0μg/ml时,WLI较BIS值明显升高(P0.01)。缝皮停药后WLI和BIS值均呈上升趋势(P0.05),与BIS值比较,停药后1～6minWLI明显升高(P0.01)。意识消失时WLI(57.8±6.7)和BIS值(57.7±5.7)差异无统计学意义。意识恢复时WLI(82.4±5.9)明显高于BIS值(76.3±5.5)(P0.01)。经Bland-Altman一致性分析,WLI和BIS在诱导和苏醒期间一致性在可接受范围内(偏差为-4.2,2SD为11.7%和-24.7%)。结论在靶控输注丙泊酚和雷米芬太尼进行全麻时,WLI具有和BIS相似的麻醉深度监测作用。     

监测脑电双频谱指数预防全麻患者术中知晓的效果:meta分析

目的 采用meta分析评价脑电双频谱指数(BIS)监测用于预防全麻患者术中知晓的效果.方法 检索Cochrane Central Register of Controlled Trials (Central)、Pubmed、Medline、EMBASE等数据库有关BIS监测与未应用BIS监测全麻患者术中知晓效果的临床、随机、对照研究.应用Cochrane协作网系统评价法对纳入文献质量进行评价和资料提取,评价指标为术中知晓发生率.采用RevMan5.1软件进行meta分析.结果 共纳入5项研究,包括34181例患者,其中应用BIS监测患者17432例,术中知晓发生率0.132％;未应用BIS监测患者16749例,术中知晓发生率0.245％,BIS监测组与未应用BIS监测组术中知晓发生率比较差异无统计学意义(P＞0.05);根据麻醉方式不同进一步分析:在吸入麻醉中,应用BIS监测患者13288例,术中知晓发生率0.128％,未应用BIS监测患者13202例,术中知晓发生率0.113％,BIS监测组与未应用BIS监测组术中知晓发生率比较差异无统计学意义(P＞0.05);在全凭静脉麻醉中,应用BIS监测患者4144例,术中知晓发生率0.145％,未应用BIS监测患者3547例,术中知晓发生率0.733％,BIS监测组术中知晓发生率明显低于未应用BIS监测组(P＜0.01).结论 监测BIS可预防全凭静脉麻醉患者术中知晓的发生,但不能预防吸入麻醉患者术中知晓的发生.     

国产麻醉深度检测仪与脑电双频谱指数在全麻镇静深度监测中的比较

目的：探讨国产麻醉深度检测仪与脑电双频谱指数在全身麻醉手术镇静深度监测中的相关性及安全性。方法：择期行全身麻醉手术40例,采用自身对照研究,患者入室后同时进行国产麻醉深度检测仪（记录麻醉深度指数,Cerebral State Index,CSI）与脑电双频谱指数（Bispectral Index,BIS）监测,记录麻醉诱导前（t0）、插管后3min（t1）、切皮即刻（t2）、切皮后30min（t3）、术毕（t4）、拔管时（t5）及出手术室时（t6）的CSI和BIS值（每个时点记录3组数据）,并观察不良反应发生情况。结果：所有患者监测部位均未发生不良反应,各时点CSI和BIS变化一致,组间比较差异无统计学意义（P〉0.05）。结论：国产麻醉深度检测仪与BIS具有良好相关性,能较好反映围术期麻醉深度变化,使用安全可行。     

Influence of bispectral index monitoring on decision making during cardiac anesthesia

STUDY OBJECTIVE: To assess bispectral index (BIS) monitoring on decision making during cardiac surgery with cardiopulmonary bypass (CPB) by measuring the number of preset standardized comments with and without knowing the BIS value and by classifying the interventions following the BIS data. DESIGN: Prospective, randomized study. SETTING: University Hospital. PATIENTS: One hundred twenty-one patients scheduled for elective cardiac surgery (89 coronary patients, 24 valve replacement patients, and 8 valve replacement and coronary surgery). INTERVENTIONS: Patients were divided into 3 groups. An observing anesthesiologist recorded on a special form ("parallel" anesthesia record) data from the devices of the workstation and the BIS monitor. Conditions in which BIS monitoring was subjectively considered that might have been useful in anesthetic decision making were recorded as "events." In group A (36 patients), the responsible anesthesiologist had continuous access to BIS information. In group B (44 patients), intraoperative anesthetic management was "blinded" to BIS values, whereas in group C (41 patients), the anesthesiologist observing the BIS monitor was free to inform the attending anesthesiologist about the BIS score. The number of events was considered as negatively reflecting the quality of the clinical course of a patient. The reduction of events was considered as improvement in decision making. All patients received the same anesthetic regimen (propofol + remifentanil). Monitoring was equal in all cases. Mild hypothermic CPB was applied in 73 patients. Statistical analysis used 1-way analysis of variance, Student 2-tailed t test, and chi2 analysis. MAIN RESULTS: Patient demographic data, underlying pathology, operation performed, hypothermia application, times of anesthesia, duration of operation, and CPB were similar in the 3 groups. In group B, the BIS value was considered by the observer as useful to know in 220 events (5.00 +/- 1.58 per patient). In group C, the BIS value was considered by the observer as useful to know in 143 events (3.49 +/- 1.31 per patient, P < 0.001) and, at the same time, the attending anesthesiologist was informed about BIS. In 112 (78.3%) cases, measures were taken. Titration of anesthetic drugs was done in 79 (70.5%) patients, whereas titration of vasoactive drugs was done in 9 (8.0%) patients, titration of both in 13 (11.6%) patients, and other diagnostic or corrective actions in 11 (9.8%) patients. Distributions of BIS values did not differ statistically (39.19 +/- 10.32, 37.38 +/- 10.21, and 38.29 +/- 10.01 in group A, group B, and group C, respectively). "Zenith" and "nadir" BIS values after induction also did not differ statistically. Awakening and extubation times were similar in both groups. CONCLUSIONS: Subjectivity, although reduced as much as possible, can play a confining role in the value of our results. The usefulness of BIS monitoring is shown by the fact that BIS data resulted in corrective measures. Attending anesthesiologist's actions, based on BIS information, reduced the events in group C.     

心率变异性分析指标与脑电双频指数在麻醉深度监测中的相关性研究

目的 探讨全身麻醉深度监测中反映迷走神经活动性的心率变异性(HRV)分析指标和脑电双频指数(BIS)的变化及相关性.方法 择期行经鼻蝶入路垂体瘤切除手术的患者35例,ASA Ⅰ或Ⅱ级,测定麻醉诱导前(T0)、诱导插管(T1)、术中(T2)、停药后(T3)各5 min的HR、MAP、BIS、相邻RR间期差的均方根(RMSSD)、高频(HF)和散点图短轴(SDl)变化.结果 T1时HR明显快于、MAP明显高于T0时(P＜0.05或P＜0.01);T2时HR明显慢于、MAP明显低于T0时(P＜0.01);T3时HR明显快于、MAP明显高于T2时(P＜0.01).T1～T3时RMSSD、HF、SD1和BIS明显低于T0时,且T2时降低更为明显,而T3时明显高于T2时(P＜0.01).结论 反映迷走神经活动性的HRV指标RMSSD、HF、SD1与BIS在监测麻醉深度时有一定的相关性.     

肌松药对脑电双频指数监测麻醉深度的影响

脑电双频指数(bispectral index,BIS)是基于原始脑电图的一种麻醉深度监测指标,近年来已广泛用于临床.术中监测麻醉深度能提高麻醉质量和手术安全性,通过合理调控麻醉深度,减少麻醉用药量和避免麻醉并发症的发生.但是.关于BIS监测在临床麻醉中应用的实际意义或价值以及BIS值判读准确性及可能的影响因素仍是人们一直关心的热点问题,结合近期国内外有关文献,现就肌松药对BIS监测麻醉深度的影响及相关临床应用情况作一综述.     

Epidural ropivacaine anesthesia decreases the bispectral index during the awake phase and sevoflurane general anesthesia

The sedative effects of epidural anesthesia without volatile and IV anesthetics and quantification of the degree of epidural anesthesia-induced sedation have not been investigated. In the current study we evaluated the effects of epidural anesthesia on the bispectral index (BIS) during the awake phase and during general anesthesia. After placing the epidural catheter, the patients were randomly allocated to 2 groups receiving either 5 mL of epidural saline (group S) or the same volume of 0.75% ropivacaine (group R). The BIS measurements during the awake phase were performed at 7, 12, 13, 14, 22, and 23 min after the epidural injection. General anesthesia was then induced with propofol and vecuronium and maintained with 0.75% sevoflurane. From approximately 10 min after tracheal intubation, the BIS measurements were made at 1-min intervals for 10 min. The BIS during the awake phase was significantly lower in group R than in group S (P < 0.05). The BIS during general anesthesia was significantly lower in group R than in group S (P < 0.0001). Epidural anesthesia decreased the BIS during the awake phase and during general anesthesia. The decrease of the BIS associated with epidural anesthesia was more prominent during general anesthesia than during the awake phase.     

听觉诱发电位和脑电双频指数预测全麻中内隐记忆的价值

目的探讨在外科麻醉深度下,脑电双频指数（BIS）和中潜伏期听觉诱发电位（MLAEP）预测内隐记忆的价值.方法选择ASA Ⅰ～Ⅱ级择期全麻下行上腹部手术的病人39例,随机分为两组,观察组（T组）术中反复听8个双字词,时间为10 min,病人清醒后2 h作记忆测试;对照组（C组）术中听海浪声.T组根据测试结果再分为击中目标词病人（T1组）和未击中目标词病人（T2组）,作BIS与MLAEP中Na、Pa潜伏期和Na至Pa的波幅（ANa-Pa）比较.结果两组病人均无外显记忆.C组19例中有3例击中目标词5个,T组20例中有8例击中目标词16个（P＜0.05）.与T1组比较,T2组MLAEP中Na、Pa潜伏期显著延长,ANa-Pa显著变小（P＜0.05）,而BIS无显著性差异.结论与内隐记忆未受到抑制的病人比较,内隐记忆形成被抑制的病人MLAEP明显被抑制,Na、Pa潜伏期显著延长,ANa-Pa显著减小,而BIS无明显变化.因此,MLAEP预测术中听觉刺激的内隐记忆的作用优于BIS.     

Update on bispectral index monitoring

Since 1997, bispectral index (BIS; Aspect Medical Systems Inc., Natick, MA) has been in clinical practice and a wealth of experimental research has accumulated on its use. Originally, the device was approved only for monitoring hypnosis and has now received an indication for reducing the incidence of intraoperative awareness during anesthesia. Numerous studies have documented the ability of BIS to reduce intermediate outcomes such as hypnotic drug administration, extubation time, postoperative nausea and shortened recovery room discharge. Two recent large-scale outcome studies using BIS (one randomized controlled trial and one prospective, nonrandomized historical cohort study) identified an approximately 80% reduction in the incidence of recall after anesthesia. BIS provides clinicians with unique information that can be used to tailor hypnotic drug doses to individual patient requirements. BIS does not predict movement or hemodynamic response to stimulation, nor will it predict the exact moment consciousness returns. This review will also discuss other BIS applications including use in pediatrics, intensive care and for procedural sedation. Some limitations exist to the use of BIS and it is not useful for some individual hypnotic agents (ketamine, dexmedetomidine, nitrous oxide, xenon, opioids). BIS technology is moving out of the operating room and into diverse environments where conscious and deep sedation are provided. Anesthesiologists need to be actively involved in promoting patient safety and helping transition this technology into broader use.     

脑电双频指数监测临床应用的新进展

背景 麻醉深度判断一直是临床医师非常关注的问题.脑电双频指数（bispectral index,BIS）监测是目前应用最为广泛的量化麻醉深度的监测手段,随着BIS监测的普及,其应用价值也不断得到更深入的认识. 目的 就BIS临床应用的新进展作一综述. 内容 术中BIS监测可以使麻醉医师以适合的麻醉深度为目标个体化按需给药,既有助于避免麻醉过浅导致术中知晓,也可避免不必要的麻醉过深而造成的术后恢复延迟,这对于慢性肝病患者的麻醉尤其重要.术中BIS监测有助于通过避免麻醉过深加快患者术后认知功能恢复,并可能改善患者远期预后.对于围术期全脑缺血的高危患者,术中BIS突然下降可能提示脑灌注不足.BIS监测可能还有助于对心跳骤停、心肺复苏后患者的预后判断,但用于预后判断的最佳监测时间和界值仍有待进一步研究阐明. 趋向 术中BIS监测能够预防术中知晓和避免麻醉过深,降低术后谵妄的发生率,并在肝病患者神志判断和麻醉、高危手术围术期脑缺血监测及心肺复苏患者的预后判断等领域有很好的应用价值.     

A prospective study of bispectral index scoring in mentally retarded patients receiving general anesthesia

Study ObjectiveTo determine whether degree of mental retardation (MR) affects bispectral index scale (BIS) scores during general anesthesia.DesignProspective clinical study.SettingUniversity Hospital.Patients80 ASA physical status I, II and III patients with varying degrees of MR, undergoing dental rehabilitation.InterventionsPatients were grouped into mild, moderate, severe or profound degrees of MR, by an independent registered research nurse according to criteria by the American Psychiatric Association.MeasurementsAll patients were given a standard sevoflurane in oxygen anesthetic with ASA standard monitoring. A research assistant who was blinded to study group assignment recorded the BIS scores continuously on a computer and compared the scores at the following time points: awake, induction of anesthesia, intravenous catheter placement, tracheal intubation, start of surgery, end of surgery, awakening to commands, and tracheal extubation.Main ResultsNo significant differences in BIS scores existed among the study groups at any time point. No significant difference in slope of induction of anesthesia was noted among the study groups. However, the slope of emergence from anesthesia leading to tracheal extubation showed a significantly longer emergence time in the higher MR groups.ConclusionMR does not affect BIS values during general anesthesia.     

国产麻醉深度监测仪和脑电双频指数监测仪在腹腔镜手术中的一致性分析

目的比较国产麻醉深度监测(Ai,ConView YY-105型)和脑电双频指数(bispectral index,BIS)监测在腹腔镜手术中的一致性。方法择期腹腔镜手术25例,男9例,女16例,年龄20~50岁,ASAⅠ或Ⅱ级,每例患者均同时监测Ai指数和BIS指数,常规麻醉诱导插管,术中以静-吸复合麻醉维持。记录诱导前、插管成功即刻、插管后5min、气腹完成即刻、拔管前即刻、拔管后5min的BIS指数和Ai指数,采用Bland-Altman一致性分析两个指数。结果 Bland-Altman一致性分析结果显示,仅插管完成即刻Ai指数和BIS值差值均数差异较大为-17.3,其余时点仅1例(4%)在一致性范围外。结论国产麻醉深度监测仪和BIS监测一致性较好,均能客观反映患者实时麻醉深度。     

BIS监测异丙酚复合瑞芬太尼全麻患儿麻醉深度的准确性

目的 评价脑电双频谱指数(BIS)监测异丙酚复合瑞芬太尼全麻患儿麻醉深度的准确性.方法 择期手术患儿60例,ASA Ⅰ或Ⅱ级,年龄3～8岁,体重14～40kg,随机分为4组(n=15),人室后开放手背静脉,稳定5 min.C组静脉输注0.9%生理盐水0.2 ml·kg-1·h-1;R1组、R2组和R3组分别静脉输注瑞芬太尼0.1、0.3或0.5 μg·kg-1·min-1,瑞芬太尼或生理盐水输注10 min开始靶控输注异丙酚,起始效应室浓度为1 μg/ml,逐渐递增至2、3、4μg/ml.分别于稳定5min、瑞芬太尼静脉输注10min、异丙酚效应室浓度达到l、2、3、4μg/ml稳定1 min及意识消失时记录BIS和警觉,镇静(OAA/S)评分;记录意识消失时间.采用logistic回归法计算意识消失时的BIS50、BIS95和意识消失时异丙酚的EC50、EC95.BIS与OAA/S评分、异丙酚效应室浓度作直线相关分析.结果 C组、R1.组、R2组和R3组BIS与OAA/S评分均呈正相关,r分别为0.89、0.90、0.87、0.82(P<0.05);BIS与异丙酚效应室浓度均呈负相关,r分别为-0.87、-0.90、-0.87、-0.92(P<0.05);与C组比较,其余3组患儿意识消失时异丙酚效应室浓度降低,意识消失时间缩短,R2组和R3组意识消失时BIS升高,BIS50和BIS95升高,异丙酚EC50和EC95降低(P<0.05);与R1组比较,R2组BIS50和BIS95升高,R3组异丙酚EC50和EC95降低(P<0.05).结论 瑞芬太尼复合异丙酚麻醉下,采用BIS监测患儿麻醉深度存在一定局限性.     

The effect of bispectral index monitoring on end-tidal gas concentration and recovery duration after outpatient anesthesia

We performed this study to determine whether instituting monitoring of bispectral index (BIS) throughout an entire operating room would affect end-tidal gas concentration (as a surrogate for anesthetic use) or speed of recovery after outpatient surgery. Primary caregivers (n = 69) were randomly assigned to a BIS or non-BIS Control group with cross-over at 1-mo intervals for 7 mo. Data were obtained in all outpatients except for those having head-and-neck surgery. Mean end-tidal gas concentration and total recovery duration were compared by unpaired t-test. Overall, 469 patients (80%) received propofol for induction and sevoflurane for maintenance. This homogeneous group was selected for statistical analysis. Mean end-tidal sevoflurane concentration was 13% less in the BIS group (BIS, 1.23%; Control, 1.41%; P < 0.0001); differences were most evident when anesthesia was administered by first-year trainees. Mean BIS values were 47 in the BIS-Monitored group. Total recovery was 19 min less with BIS monitoring in men (BIS group, 147 min; Controls, 166 min; P = 0.035), but not different in women. We conclude that routine application of BIS monitoring is associated with a modest reduction in end-tidal sevoflurane concentration. In men, this may correlate with a similar reduction (11%) in recovery duration.