听觉诱发电位指数用于诱导插管期间麻醉深度监测的临床评价

目的 观察听觉诱发电位指数在全麻诱导插管期间的变化，评价其用于临床麻醉深度监测的有效性。方法 ASAⅠ-Ⅱ级，全麻下行择期手术的病人40例。依次给予咪唑安定0.06mg/kg，芬太尼4μg/kg，丙泊酚0.5mg/kg，维库溴铵0.1mg/kg诱导后，行气管插管，观察诱导前，气管插管前，插管时及插管后1-5分钟等8个时点的AEPI，BIS，HRV，SEF及MAP，HR和RPP的变化。结果 诱导后各观察指标较诱导前的基础值均有所降低，插管后BIS，HRV，SEF等指标均在5分钟内回复至插管前水平，AEP在第3分钟即可回复至插管前水平，插管前后几项观察指标变化趋势相一致。结论 AEPI，BIS，HRV，SEF均能有效反映插管的应激反应。AEPI较其他几项指标更为迅速灵敏，可作为麻醉深度监测的有效指标。     

Auditory evoked potentials during isoflurane anaesthesia

Brainstem auditory evoked potentials (BAEP) were determined in 12 volunteers. The effect of isoflurane anaesthesia on BAEP was determined in six patients. Body temperature and end-tidal CO2% were controlled. Increasing end-tidal isoflurane concentration from 0.6-2.4% increased BAEP wave I, III and V latencies. The amplitude of wave V decreased with increasing isoflurane concentration. Thus a dose-related change was demonstrated between end-tidal concentration of isoflurane and BAEP latencies.     

Midlatency auditory evoked potentials during anaesthesia with increasing endexpiratory concentrations of desflurane

Background. Under general anaesthesia with the volatile anaesthetics halothane, enflurane and isoflurane, midlatency auditory evoked potentials (MLAEP) are suppressed dose-dependently. Therefore, MLAEP have been used to measure depth of anaesthesia and to indicate intraoperative awareness. Desflurane is a new volatile anaesthetic and its effects on MLAEP have not been studied previously.
Methods. We have studied MLAEP during general anaesthesia with increasing endexpiratory concentrations of desflurane in 12 patients scheduled for elective gynaecological surgery. Auditory evoked potentials were recorded in the awake state and during anaesthesia with endexpiratory steady state concentrations of 1.5, 3.0, 4.5 and 6.0 vol %, of desflurane on vertex (positive) and mastoids on both sides (negative). Latencies of the peaks V, Na, Pa, Nb, Pl (ms) and amplitudes Na/Pa, Pa/Nb and Nb/Pl (μV) were measured.
Results. In the awake state, MLAEP had high peak-to-peak amplitudes and a periodic waveform. During general anaesthesia with increasing endexpiratory concentration of desflurane, the latency of the brainstem response V increased only slightly. In contrast, MLAEP showed a marked dose-dependent and statistically significant increase in latencies of Na, Pa, Nb and Pl and decrease in amplitudes of Na/Pa, Pa/Nb and Nb/Pl. Under 6.0 vol % of desflurane MLAEP were severely attenuated or even abolished.
Conclusion. Based on these observations, endexpiratory concentrations of ≥4.5 vol % desflurane should suppress awareness phenomena such as auditory perceptions during anaesthesia.     

听觉诱发电位指数在麻醉深度监测中的作用

目的观察腹腔镜胆囊切除术(LC)中丙泊酚靶控输注(TCI)或异氟醚吸入维持麻醉期间听觉诱发电位指数(AAI)在麻醉深度监测中的作用。方法33例ASAⅠ级择期行LC的患者,随机分为两组:异氟醚组(I组)18例行诱导插管吸入全麻,丙泊酚组(P组)15例诱导插管同I组;麻醉维持分别用异氟醚与氧化亚氮吸入或丙泊酚靶控输注与氧化亚氮吸入。通过调节异氟醚吸入浓度或丙泊酚靶控输注浓度使麻醉期间MAP、HR波动在基础值±20%范围内,记录麻醉期间异氟醚呼气末浓度、丙泊酚靶控输注浓度及AAI值。结果两组AAI值均较低,P组出现一过性AAI值≤10有12人次,I组则有4人次;且AAI值与丙泊酚靶控输注浓度及异氟醚呼气末浓度呈负相关(P<0.05),与MAP、HR无明显相关。结论结合AAI监测可更全面的反映麻醉深度。     

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.     

Midlatency auditory evoked potentials in children: effect of age and general anaesthesia

BACKGROUND: Midlatency auditory evoked potentials (MLAEP) are a promising tool for monitoring suppression of sensory processing during anaesthesia and might help to avoid awareness. MLAEP in children are different to those in adults and the exact changes during general anaesthesia are unknown. METHODS: In 49 children of age between 2 and 12 yr, MLAEP were recorded before anaesthesia, during tracheal intubation, at steady-state balanced anaesthesia, and after extubation. RESULTS: MLAEP were recordable in all children in the awake (premedicated) state with latencies but not amplitudes dependent on children's age. MLAEP latencies significantly increased during tracheal intubation and steady-state anaesthesia. Changes in amplitudes were inconsistent. All MLAEP variables returned to near baseline values after extubation. CONCLUSIONS: The results of this study imply that MLAEP can successfully be recorded during anaesthesia in children above the age of 2 yr. Further studies are necessary before MLAEP might be applicable for monitoring purposes in paediatric anaesthesia.     

不同静脉麻醉药对听觉诱发电位指数的影响

目的　研究丙泊酚、咪唑安定、硫喷妥钠、氯胺酮麻醉时听觉诱发电位指数 (AEPI)的变化规律。方法　 4 8例择期手术拟行全身麻醉、无听力障碍和严重神经疾患、非颅脑手术病人 ,随机分为四组。Ⅰ组 (14例 )静注丙泊酚 2mg/kg ;Ⅱ组 (13例 )静注咪唑安定 0 2mg/kg ;Ⅲ组 (11例 )静注硫喷妥钠 5mg/kg ;Ⅳ组 (10例 )静注氯胺酮 2mg/kg。随后芬太尼 5 μg/kg、维库溴铵 0 15mg/kg静注 ,肌松满意后气管插管。记录麻醉诱导前、诱导中、诱导后插管前、插管后的HR、BP、SpO2 ,观察整个诱导期AEPI的变化规律。结果　Ⅰ、Ⅱ、Ⅲ组病人用药后AEPI进行性降低至 30以下。降到 30以下的平均时间分别为Ⅰ组 (6 2± 2 5 )分钟、Ⅱ组 (3 2± 1 9)分钟、Ⅲ组 (5 1± 2 6 )分钟 ;Ⅳ组病人AEPI无明显下降。插管后AEPI有上升趋势 ,吸入异氟醚后 (呼出气浓度 >0 8Vol% )能维持AEPI30以下 ;Ⅳ组病人插管后AEPI不稳定。结论　丙泊酚、咪唑安定、硫喷妥钠降低AEPI,而氯胺酮对AEPI无明显影响。AEPI在丙泊酚、咪唑安定、硫喷妥钠麻醉中可作为麻醉深度监测的指标之一。     

Recording the middle latency response of the auditory evoked potential as a measure of depth of anaesthesia. A technical note

The middle latency response of the auditory evoked potentialmay be useful as an indicator of the hypnotic state during anaesthesia.However, it is difficult to record in some circumstances. Thiscommunication provides some suggestions and guidance for thosenot familiar with the technique. Br J Anaesth 2004; 92: 442–5     

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。     

听觉诱发电位指数调控老年人靶控输注丙泊酚麻醉的研究

目的　研究听觉诱发电位指数 (AEPI)调控持续靶控输注 (TCI)丙泊酚在老年人麻醉中的可行性。方法　 30例ASAⅠ～Ⅱ级择期胃切除手术的病人分为老年组 (>6 5岁 ,Ⅰ组 )和中青年组 (2 0～ 5 9岁 ,Ⅱ组 ) ,每组 15例。诱导前静注芬太尼 2 μg/kg。丙泊酚的靶效应室浓度设定为3 5 μg/ml。两组丙泊酚效应室浓度均根据AEPI调整 ,使麻醉深度控制在 :插管时 35～ 4 5 ,切皮时2 0～ 30 ,探查时 15～ 2 5 ,关腹时为 2 5～ 35。在 8个时间点监测并记录心率 (HR)、收缩压 (SBP)、舒张压 (DBP)、平均动脉压 (MAP)、AEPI、丙泊酚的总量和麻醉时间。结果　两组病人平均丙泊酚标准化剂量 :Ⅰ组为 10 6 4 3μg·kg 1·min 1、Ⅱ组为 12 3 6 1μg·kg 1·min 1。两组插管前时SBP、DBP、MAP同基础值相比都没有显著变化 ,但插管后 5min时与基础值比较 ,血液动力学下降在老年人中较为显著(P <0 0 5 ) ,而中青年人的较为稳定。在术中探查时其血液动力学都有所回升 (P <0 0 5 ) ,停药时、睁眼时及拔管时与基础值比较 ,血液动力学无显著变化。结论　以AEPI调控持续靶控输注丙泊酚在对老年人麻醉是可行的 ,可保持血液动力学相对稳定 ,减少老年人麻醉用药量。     

Awareness detected by auditory evoked potential monitoring

We report a case of awareness detected by the Alaris AEP Monitor,a device that measures anaesthesia by tracking changes of thewaveform of the mid-latency auditory evoked potential. Br J Anaesth 2003; 91: 290–2     

脑干听觉诱发电位与异氟醚麻醉浓度定性及定量关系的研究

对１０例患者研究了脑干听觉诱发电位（ＢＡＥＰ）潜伏期与异氟醚麻醉浓度定性及定量关系。全麻诱导采用２．５％硫喷妥钠（３～５ｍｇ／ｋｇ），阿曲库铵（０．６ｍｇ／ｋｇ）。气管插管后麻醉维持采用１．１５％、１．７３．％、２．３０％异氟醚及６０％Ｎ２Ｏ，肌松维持用阿曲库铵。记录麻醉前、诱导后，１．１５％、１．７３％、２．３０％及减至１．１５％异氟醚时ＢＡＥＰ峰潜期（ＰＬ）和峰间潜伏期（ＩＰＬ）值。结果表明，ＢＡＥＰ波ＶＰＬ能稳定反映异氟醚麻醉浓度变化，具有等级性并呈正相关关系，ＢＡＥＰＰＬ、各波正常值似可作为判断异氟醚麻醉深度的参考标准。     

Mid-latency auditory evoked response during propofol and alfentanil anaesthesia

Background. Propofol has been shown to affect the mid-latencyauditory evoked response (MLAER) in a dose-dependant manner.Few studies have investigated the addition of alfentanil. Myogenicresponses, such as the post-auricular responses (PAR), can confoundthe MLAER but there has been little investigation as to whichelectrode site reduces this interference. Methods. We studied the MLAER in 27 women. They received aninfusion of alfentanil 15 µg kg^–1 h^–1, followedby either a high or low infusion regimen of propofol (finalinfusion rates 6 and 3 mg kg^–1 h^–1). We comparedthe results with those of our study using propofol alone. Wecollected the data from two electrode sites: vertex–inionand vertex–mastoid. We evaluated the occurrence of thePAR and the shape of the MLAER at each electrode site. Results. The infusion rate of propofol associated with lossof the eyelash response in 50% of subjects was 3.3 mg kg^–1h^–1. This was significantly lower than using propofolalone (5.8 mg kg^–1 h^–1). Nb latency was the bestMLAER discriminator of unconsciousness (sensitivity 94%, specificity88%), with a threshold of 46 ms (propofol alone was 53 ms).The addition of alfentanil did not alter the relationship betweenpropofol infusion rate and MLAER. The vertex–inion electrodesite gave the best protection against PAR in awake subjects(P=0.0003), and after 30 min of propofol infusion (P=0.06).The magnitude of the MLAER obtained from the vertex–mastoidelectrodes was larger than from the other site, although theincrease was not consistent throughout the waveform (brain stem100%, Nb 14%). Conclusions. Addition of alfentanil lowers the propofol infusionrate required to produce unconsciousness and the Nb latencythat predicts it. The better of the two sites to reduce theincidence of PAR is the vertex–inion electrode site. Br J Anaesth 2004; 92: 25–32     

Effects of the auditory stimuli of an auditory evoked potential system on levels of consciousness, and on the bispectral index

Investigators in the field of depth of anaesthesia monitoringsometimes measure the auditory evoked potential (AEP) and theBispectral Index (BIS) concurrently. However, the auditory stimulirequired to generate an AEP may increase the level of consciousness,and cause an increase in the BIS. They may also alter the BISby producing phase-locked harmonics in the surface electroencephalogram.The aim of this study was to determine if AEP stimuli have clinicallysignificant effects on levels of consciousness and BIS valuesduring sedation and general anaesthesia. Ten healthy adult patientswere studied by measuring and recording the BIS for 6 epochsof 5 min each. The first 3 epochs took place during steady-statesedation, during which time the Observer’s Assessmentof Awareness/Sedation (OAA/S) score was also measured. The second3 epochs took place during steady-state anaesthesia. Duringalternate epochs, patients were subjected to the auditory stimuligenerated by an AEP system. The auditory stimuli were not associatedwith a change in BIS values (during sedation and anaesthesia)or OAA/S scores (sedation). Br J Anaesth 2001; 87: 778–80     

浅低温对脑干听觉诱发电位的影响

目的　观察浅低温对神经外科麻醉病人脑干听觉诱发电位 (BAEP)的影响。方法　ASAⅠ～Ⅱ级无明显听力障碍的择期神经外科手术病人 1 2例 ,在麻醉诱导插管后通过调温床给予浅低温治疗。在降温前及体温达 34℃时各记录一次BAEP ,比较降温前后Ⅴ波绝对潜伏期及Ⅰ Ⅴ波间潜伏期变化。结果　麻醉诱导后病人体温为 (35 9± 0 3)℃ ,Ⅴ波绝对潜伏期为 (6 0 0± 0 57)毫秒 ,Ⅰ Ⅴ波间潜伏期为 (4 52± 0 48)毫秒 ;降温至 34℃时 ,Ⅴ波绝对潜伏期为 (6 31± 0 36)毫秒 ,Ⅰ Ⅴ波间潜伏期为 (4 73± 0 46)毫秒。降温后Ⅴ波绝对潜伏期及Ⅰ Ⅴ波间潜伏期均有延长趋势。结论　临床上体温降低 1～ 2℃对BAEP无明显影响     

听觉诱发电位指数监测患者吸入异氟醚麻醉深度的准确性

Objective To evaluate the accuracy of auditory evoked potential index (AAI) in monitoring the anesthetic depth during isoflurane anesthesia.Methods Thirty ASA Ⅰ or Ⅱ patients aged 18-55 years and undergoing elective surgery under general anesthesia were enrolled in this study. The patients were unpremedicated. Anesthesia was induced with midazolam 0.05 mg/kg, fentanyl 3 μg/kg and propofol 1 mg/kg. Tracheal intubation was facilitated with recuronium 0.1 mg/kg. The patients were mechanically ventilated (VT:40 mm Hg. Anesthesia was maintained with isoflurane inhalation and intermittent intravenous boluses of vecuronium. Isoflurane was started with high-flow (FGF, 3 L/min) for 12 min followed by low-flow (LGF, 0.5 L/min). The inspired isoflurane concentration was set at 3%. The electrocardiogram (ECG), mean arterial pressure (MAP), heart rate (HR), pulse oxygen saturation (SpO2), end-tidal isoflurane concentration and AAI were continuously monitored during anesthesia and recorded before induction of anesthesia (baseline, To ), immediately after induction (T1), immediately before isoflurane inhalation (T2), at 3 min(T3), 6 min (T4), 9 min (T5) and 12 min (T6) during high-flow wash-in and at the end-tidal isoflurane concentrations of 0.8 MAC (T7), 1.0 MAC (T8) and 1.3 MAC (T9) during low-flow inhalation of isoflurane, respectively.Results AAI decreased gradually while the end-tidal isoflurane concentration increased during high-flow wash-in. And AAI was negatively correlated with the end-tidal isoflurane concentrations ( r = -0.896, P ＜ 0.01 ) during low-flow inhalation of isoflurane anesthesia.     

The effect of tracheal intubation and surgical stimulation on median nerve somatosensory evoked potentials during anaesthesia

This study was designed to determine whether alterations in the median nerve somatosensory evoked potentials occur during the stimuli of tracheal intubation and skin incision. Twenty-two patients scheduled for elective surgery and who required tracheal intubation were studied. Median nerve somatosensory evoked potentials were recorded, analysed and stored approximately every 40 seconds. Anaesthesia was induced with thiopentone and vecuronium used for neuromuscular blockade; the trachea was intubated 2 minutes after induction. Fentanyl 1.5 micrograms/kg was administered subsequently. Evoked potential monitoring was continued until at least 2 minutes after surgical incision. Induction of anaesthesia was associated with an increase in evoked potential latency of 0.8 msec and reduction in amplitude of 1.7 microV. Small, statistically insignificant changes occurred between induction of anaesthesia and tracheal intubation. Surgical incision was accompanied by a statistically significant mean decrease in evoked potential latency of 0.5 msec and a statistically significant increase in evoked potential amplitude of 0.6 microV. The fact that surgical stimulation produced an activating effect on evoked potentials suggests that they may be used as a measure of the neurophysiological effects of anaesthesia.     

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.     

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