全身麻醉对小儿听性脑干反应测试结果的影响

目的　研究应用听性脑干反应 (auditorybrainstemreaction ,ABR)作为监测小儿全身麻醉深度与觉醒的客观指标。方法　选择听力正常的外科择期手术患儿 4 5例 ,按照美国麻醉学家学会表针分为Ⅰ～Ⅱ级 ,分别施行异丙酚静脉麻醉、芬太尼静脉麻醉及异氟醚吸入全身麻醉 ,随机每组 15例 ,应用丹麦Madsen诱发电位反应仪监测并记录麻醉各阶段ABR的Ⅰ、Ⅲ、Ⅴ波潜伏期及Ⅰ Ⅲ、Ⅲ Ⅴ、Ⅰ Ⅴ波间期 ,研究观察潜伏期和波间期随时间推移及麻醉剂量变化之间的关系 ,探讨ABR在异丙酚、芬太尼及异氟醚等不同麻醉中的表现特征和规律。结果　①异丙酚静脉麻醉和异氟醚吸入麻醉与剂量呈良好的正相关 ;②Ⅰ波的潜伏期特性对于控制麻醉深度极为重要 ;③Ⅴ波监测麻醉具有最佳的稳定性及相关性 ;④停用麻醉药一段时间或患儿基本清醒时 ,ABR各波潜伏期和波间期有的仍高于正常值 ,这是滞后 (延迟 )反应 ;⑤ABR对芬太尼术中的觉醒监测不太敏感。结论　ABR各波的潜伏期及波间期变化 ,可判断小儿全身麻醉深度 ,在一定程度上可作为判断觉醒的参考 ,但应考虑有延迟反应的可能     

脉冲角加速度刺激诱发豚鼠短潜伏期前庭诱发电位

以脉冲角加速度刺激在豚鼠记录出短潜伏期诱发反应，反应由发生于刺激开始后10ms以内的5～7个波组成，高强度刺激时反应振幅数微伏，I波潜伏期约2．5ms，不同动物及同一动物不同时间测试反应非常稳定。系列实验结果表明脉冲角加速度刺激诱发的豚鼠短潜伏期诱发反应系前庭诱发电位。     

Changes in rapidly extracted auditory evoked potentials during tracheal intubation

BACKGROUND: One of the problems encountered in assessment of the hypnotic level during anesthesia is the extraction of a consistent and reliable measure online and close to real time. Hemodynamic parameters such as heart rate and blood pressure are not, at least with the traditional single parameter versus time presentation, adequate for ensuring an optimal level of anesthesia, especially when using neuromuscular blocking agents (NMBA). In the literature, it has been demonstrated that auditory evoked potentials (AEP) are able to provide two aspects relevant to determining level of anesthesia: firstly, they have identifiable anatomical significance and, secondly, their characteristics reflect the way the brain perceives a stimulus. METHODS: The aim of this study was to evaluate the AEP index based on a system identification model, the autoregressive model with exogenous input (ARX-model), and to compare it to the classical method, the moving time average (MTA). The ARX enables the extraction within 15-25 sweeps, depending on the signal-to-noise ratio (SNR), whereas MTA typically needs 250-500 sweeps. The hypothesis of the present study was that since the ARX-model extracts the AEP faster than the MTA-model, the former should be able to detect changes during the brief, intense stimulus of endotracheal intubation. Twelve female patients scheduled for gynecological surgery were included in the study. Anesthesia was initiated with thiopentone and maintained with isoflurane and alfentanil. The AEP was mapped into an index (AEP-index) normalized to 100 when the individual was awake and decreasing to an average of 25 during thiopentone induced anaesthesia. The results were compared to those obtained by MTA-extracted AEP. RESULTS: During tracheal intubation 9 patients showed an increase in the ARX-extracted AEP-index larger than 15, and 6 of these patients showed an increase larger than 25 (mean increase=33, SD=18). The MTA-extracted AEP-index showed only one patient with an increase larger than 15. The ARX-extracted AEP changed significantly faster than the MTA-extracted AEP. CONCLUSION: The ARX-extracted AEP-index increases during tracheal intubation. There is a significant difference between the ARX-extracted AEP and the traditional MTA-extracted AEP, in terms of response time. In order to trace short-lasting changes in the hypnotic level by AEP, the AEP should be extracted by a method with a fast response such as the ARX-model.     

Effects of Different Doses of Epidural Midazolam on Spinal Somatosensory Evoked Potentials

Summary  The aim of this study is to find out the effects of different doses of midazolam, when used epidurally, on somatosensory evoked potentials (SEP) by delaying neuronal conduction. Thirty two New Zeland albino male rabbits were divided into four groups. All rabbits were anesthetised with ketamine and xylasine combination and atracurium was used as muscle relaxant. 10 mg/kg/hr ketamine infusion was used for maintenance of anesthesia. After insertion of the epidural catheter surgically; Group 1 received 1.5 ml isotonic saline (Control), Group 2 received 150 μg/kg, Group 3 received 250 μg/kg, and Group 4 received 500 μg/kg midazolam epidurally. With the stimulation of sciatic nerve, SEP records were recorded from the epidural space. Records were received before the injection of the drug, and 20, 40, 60 minutes after injection of the drug.  “Latancy” results were increased according to control in all groups (including isotonic saline-control-group). Increase in latancy in the control group was interpreted as due to the effect of temperature mismatch of the saline and the rabbits. While in the first and second group amplitudes showed no differences, group 3 and 4 showed decreases of up to 50%. Epidurally administered midazolam up to 150 μg/kg caused no change in SEP records, but 250 and 500 μg/kg doses caused decreases in SEP records which can lead to misinterpretation as neurological damage.     

Evoked potential monitoring in anaesthesia and analgesia

Electrophysiological monitoring of selected neural pathways of the brain, brainstem, spinal cord and peripheral nervous system has become mandatory in some surgery of the nervous system where preventable neural injury can occur. Evoked potentials are relatively simple methods of testing the integrity of various aspects of the nervous system. This review covers the variety of evoked potentials that can be monitored and outlines the principles of their measurement. Their use in specific situations and how factors such as anaesthesia might affect them is presented.     

不同记录电极位置对多焦视诱发电位检查结果的影响

目的 比较不同记录电极位置对多焦视诱发电位(mf-VEP)检查结果的影响。 方法 应用RETIscan多焦视诱发电位记录系统3.20对10例正常人进行检查。记录电极位置包括两组垂直通道和两组水平通道。垂直通道作用电极和参考电极分别置于枕骨隆凸上、下方各2.0 cm（Ch1）或枕骨隆凸上方3.0 cm、下方4.5cm (Ch2)；水平通道作用电极和参考电极分别置于枕骨隆凸右、左侧各2.0 cm（Ch3）或4.0 cm (Ch4)。分别比较各通道记录的上半视野及下半视野mf-VEP的振幅之和有无显著性差异。 结果 各通道记录的上半视野及下半视野mf-VEP振幅之和的差异均有显著性的意义（F=20.273, P=0.000）；且Ch2与Ch1、Ch3、Ch4两两之间的差异也有显著性的意义（P分别为0.000 、0.000、0.001）。对于沿水平中线分布的位点，Ch2记录的mf-VEP中振幅很小的各位点的振幅之和，与Ch3、Ch4记录的mf-VEP中相应位点的振幅之和的差异有显著性的意义（F=11.304,P=0.000）；且Ch4与Ch2、Ch3两两之间的差异也有显著性的意义（P均<0.05）。 结论 与Ch1、Ch3和Ch4相比, Ch2可记录到更佳的mf-VEP。水平通道可改善垂直通道对部分位点，尤其是沿水平中线分布位点的mf-VEP的引导，其中Ch4对Ch2的改善作用较Ch3更为明显。 （中华眼底病杂志，2004，20：346-348）     

嗅球成鞘细胞移植对成年大鼠皮质脊髓束损伤的修复

目的 研究嗅球成鞘细胞(OECs)对成年大鼠皮质脊髓束损伤(CSI)的作用.方法 采用电解损毁大鼠C1-C2脊髓节段的皮质脊髓束(CST)的方法 制备脊髓损伤(SCI)模型.原代培养OECs后移植到SCI大鼠.分别进行斜板实验和皮层运动诱发电位(MEP-C)的记录,测定斜板角度以及潜伏时、阈刺激强度、波幅等电生理指标的改变.结果 与对照组比较,损伤组的斜板角度下降,MEP-C潜伏期延长,阈刺激强度增加,所记录三个峰值均减小,且各项指标均与对照组有显著性差异.这反映出大鼠CST的受损.与损伤组比较,损伤 移植组动物显示出斜板角度增大,MEP-C各项指标中,潜伏期缩短,阈刺激强度减小,所记录三个峰值均增大,且各项指标与损伤组比较有显著性差异.这提示CST的功能恢复.结论 OECs可能有促进CST修复的作用.     

听性脑干反应和畸变产物耳声发射在糖尿病患者听功能检测中的应用

目的:研究糖尿病(DM)患者听力损失特点,探讨其听性脑干反应(ABR)和畸变产物耳声发射(DPOAE)变化特征。方法:对在我院就诊的136例(272耳)DM患者(实验组)的一般情况、有无微血管并发症及听力损失程度等进行问卷调查,按每10岁分为30～40岁,>40～50岁,>50～60岁,>60～70岁4个年龄段,均对其进行纯音听阈(PTT)、声导抗、ABR和DPOAE检测,并与120例(240耳)同样分为4组的正常同龄成人(对照组)进行比较。结果:实验组30～40岁年龄段其ABRⅠ～Ⅴ波间期及反应阈与对照组比较差异无统计学意义,40岁以上患者ABR反应阈随增龄明显增加、波间期延长,而且60岁以上患者Ⅲ～Ⅴ、Ⅰ～Ⅴ波间期的延长与同龄对照组比较差异有统计学意义(P<0.05)。实验组与对照组患者的DPOAE检出率均为100%,但早期DM患者DPOAE幅值在1～8kHz均较同龄对照组降低,且以4kHz幅值减小明显,变化差异有统计学意义(P<0.05)。结论:DM患者多为双侧渐进性的轻、中度听力损害,ABR及其听阈异常与患者年龄、性别及有无微血管并发症相关,而与DM类型及病程无关。DPOAE可用于了解早期DM患者的耳蜗损害。     

Visual evoked potentials in patients with psoriasis vulgaris

Purpose: The aim of this study is an estimation of the visual evoked potentials (VEP) in patients with psoriasis vulgaris. The role of the nervous system was pointed out in the pathogenesis of psoriasis. Also epidemiologic research confirms that patients with psoriasis are at increased risk of MS development. Materials and methods: A group of 30 psoriatic males aged between 18 and 54 was examined. The results were compared with those obtained from a group of 30 healthy age-matched males and they were correlated with the psoriasis area and severity index (PASI), the skin surface area involved, duration of the disease and duration of the last relapse. In neurological and ophthalmological examinations no pathological symptoms were detected in either group. The VEP examination was executed using pattern reversal (pr) and pattern flash (pf) stimulation. Results: Using pf stimulation, in the group of patients with psoriasis vulgaris, a statistically significant elongation in the latency of P-100 and reduction of response amplitude, not related to the PASI, nor the skin surface area involved, nor duration of the last relapse, were observed. Conclusions: The results of the study indicate subclinical damage of the visual pathway in patients with psoriasis vulgaris.