不同麻醉深度下中枢神经系统的功能状态

探讨数量化脑电图与七氟醚麻醉深度的关系。方法：６２例腹部手术病人，常规麻醉诱导，气管内插管，机械通气，潘库溴铵或阿曲库铵维持肌松。手术探查毕，调查每个病人的七氟醚呼气未浓度依次达２％→１．５％→１％，每种浓度维持至少１５分钟、记录３分钟数量化ＥＥＧ及ＭＡＰ，ＨＲ变化，结果：随七氟醚呼气末浓度降低，原始脑电波逐渐由低频高振幅波转变为高频低振幅波；ＳＥＦ和ＭＦ趋势曲线明显右移；ＳＥＦ，ＭＦ，ＢＩＳ，δ     

脑电功率谱分析用于监测手术切皮时的麻醉深度

目的：评价脑电功率谱分析技术反映麻醉深度的准确性。方法：６５例ＡＳＡⅠ级腹部手术病人，快速静脉诱导气管插管后，机械通气，维持ＰＥＴＣＯ２在正常范围内。麻醉：Ｏ２－Ｎ２Ｏ（１∶２）－七氟醚吸入，切皮前不追加长效肌松药。随机分为三组：Ⅰ组ｎ＝２５、Ⅱ组ｎ＝２０、Ⅲ组ｎ＝２０。七氟醚呼气末浓度分别为１．０％、１．５％、２．０％，至少维持１５分钟。应用数量化脑电图监测仪监测手术切皮前、后３分钟脑电图的改变，同时监测ＭＡＰ、ＨＲ的改变，切皮后四肢肌肉活动、面部表情变化、呛咳或切皮前不能耐受气管插管刺激者定为切皮反应阳性。结果：切皮前三组病人的ＥＥＧ随七氟醚呼气末浓度增加，波谱边缘频率（ＳＥＦ）、中频率（ＭＦ）、双谱指数（ＢＩＳ）明显降低（Ｐ＜０．０１），δ波比率（δＲ）明显升高（Ｐ＜０．０１），ＭＡＰ仅Ⅰ组和Ⅲ组之间有差异（Ｐ＜０．０５），ＨＲ三组之间无统计学差异。切皮反应者的ＳＥＦ、ＭＦ、ＢＩＳ明显高于无反应者，δＲ明显低于无反应者（Ｐ＜０．０１）。反应者切皮前、后的ＭＡＰ和ＨＲ变化差明显大于无反应者（Ｐ＜０．０１）。结论：ＥＥＧ数量化指标ＳＥＦ和ＢＩＳ能较准确地反映切皮前七氟醚麻醉深度。     

数量化脑电图监测手术切皮时的镇痛强度

为评价数量化脑电图（ＥＥＧ）反映镇痛强度的准确性，作者对６５例ＡＳＡⅠ级腹部手术患者，快速静脉诱导气管插管后，机械通气。麻醉维持：Ｏ２－Ｎ２Ｏ（１：２）－七氟醚吸入，切皮前不追加长效肌松药，监测ＴＯＦ。随机分为三组：七氟醚呼气末浓度分别为１％（Ⅰ组）、１．５％（Ⅱ组）、２％（Ⅲ组），至少维持１５ｍｉｎ。应用数量化脑电图监测手术切皮前、后３分钟脑电图（Ｆｐ１－Ａ１，Ｆｐ２－Ａ２）和平均动脉压（ＭＡＰ）、心率（ＨＲ）的变化以及患者的切皮反应改变。结果显示，切皮前数量化ＥＥＧ随七氟醚呼气末浓度增加，波谱边缘频率（ＳＥＦ）、中频率（ＭＦ）、双谱指数（ＢＩＳ）明显降低（Ｐ＜０．０１），δ波比率（δＲ）明显升高（Ｐ＜０．０１），ＭＡＰ仅Ⅰ组和Ⅲ组之间差异有显著意义（Ｐ＜０．０５），ＨＲ三组之间差异无显著意义。切皮反应者的ＳＥＦ、ＭＦ、ＢＩＳ明显高于无反应者，δＲ明显低于无反应者（Ｐ＜０．０１）。反应者切皮前、后的ＭＡＰ和ＨＲ变化差明显大于无反应者（Ｐ＜０．０１）。作者认为，ＥＥＧ数量化指标ＳＥＦ和ＢＩＳ能较准确地反映切皮前七氟醚镇痛强度，血流动力学与七氟醚呼气末浓度无相关性，因此不能反映切皮前七氟醚镇痛强度。     

数量化脑电图监测手术切以时的镇痛强度

为评价数量化脑电图（ＥＥＧ）反映镇痛强度的准确性,作者对６５例ＡＳＡＩ级腹部手术患者,快速静脉诱导气管插管后,机械通气。麻醉维持“：Ｏ２－Ｎ２Ｏ（１：２）－七氟醚吸入,切皮带不追加长效肌松药,监测ＴＯＦ。随机分为三组：七氟醚呼气末浓度分别为１％（Ｉ组）、１．５％、２％,至少维持１５ｍｉｎ。应用数量化脑电图监测手术切皮前、后３分钟脑电图和平均动动脉压（ＭＡＰ）、心率（ＨＲ）的变化以及患者的切皮反应改     

神经外科手术异氟醚麻醉对脑电图和颅内压及血液动力学影响

目的 探讨神经外科手术中不同浓度异氟醚吸入麻醉期间脑电图（ＥＥＧ）、颅内压（ＩＣＰ）及血液动力学的变化。方法 ３０例鞍区肿瘤择期手术病人,ＡＳＡⅠ～Ⅱ级,以芬太尼、异丙酚、维库溴铵诱导插管后随机分三组,分别以０．５、１．０、１．５ＭＡＣ异氟醚维持麻醉。观察入安静平卧时、吸入氟醚浓度达指定ＭＡＣ时、切皮、锯硬膜时平均动脉压（ＭＡＰ）、心率（ＨＲ）、颅内压（ＩＣＰ）、脑电图９５％边缘频率（ＳＥＦ）及双     

脑电双频谱分析用于地氟醚复合氧化亚氮吸入时麻醉深度的判断

目的：通过观察地氟醚复合Ｎ２Ｏ吸入麻醉过程中脑电双频谱指数（ＢＩＳ）的进一步评价ＢＩＳ在麻醉深度监测中的应用价值。方法：患者２０例,气管插管后后用５０％Ｏ２＋５０％Ｎ２Ｏ＋地氟醚维持麻醉。地氟醚初始吸入浓度６％,分别于呼气末浓度达到０．５、０．７５、１．０、１．２５６ １．５ＭＡＣ时记录ＢＩＳ、Ｂ客ＨＲ等指标,然后维持呼气末２３．９％（１．３ＭＡＣ０,１５分钟后开始手术,观察切皮时患者有无反应。术     

七氟醚麻醉对犬肾脏血流的影响

选择８条杂种犬观察七氟醚麻醉的肾血流改变。静脉麻醉下完成外科准备。给犬吸入七氟醚。调整呼气末浓度依次为１％、２％、３％和４％，监测如下指标：肾血流、平均动脉压、心率、中心静脉压、心输出量和每搏量。与对照值比较。结果显示，随着麻醉的加深，ＲＢＦ、ＭＡＰ、ＨＲ、ＣＯ以剂量相关方式被抑制。呼气末浓度超过２％，ＭＡＰ降至９．３ｋＰａ，此时ＲＢＦ开始显著减少。停药后３０分钟，ＲＢＦ尚未能随血流动力学的改善而     

尼卡地平、氟哌啶和氧化亚氮预防地氟醚介导的交感活性增强

目的：观察尼卡地平、氟哌啶和氧化亚氮对快速增加呼气末对氟醚浓度超过１ＭＡＣ所引起的交感活性增强的抑制作用。方法：采用异丙酚麻醉诱导,气管插管后吸入地氟醚,呼气末浓度４％持续３０分钟后,快速增加到８％。实验组患者在升高地氟醚浓度后５分钟分别给予尼平１０μｇ／ｋｇ,氟哌啶０．０７ｍｇ／ｋｇ或吸入５０％Ｎ２Ｏ。结果：对照组在地氟醚呼气末深度快速升高到８％后１分钟,ＨＲ、ＭＡＰ分别增加３１％和２０．６％,     

地氟醚、七氟醚与安氟醚低流量麻醉临床观察

比较地氟醚、七氟醚、安氟醚用于低流麻醉时ＢＰ和ＨＲ改变,苏醒过程、不良反应以及药物费用。方法：４２例ＡＳＡＩⅠ－Ⅱ级择期腹部外科手术病人随机分成地氟醚,安氟醚和七氟醚三组。麻醉诱导后连接Ｃｉｃｅｒｏ麻醉机。降低新鲜气流,地氟醚和安氟醚为０．３－０．５Ｌ／ｍｉｎ,七氟醚为０．８－１．０Ｌ／ｍｉｎ,从回路呼出端向麻醉机回路内注入液吸入麻醉药４－５分钟内使三组病人呼气末麻醉药浓度达到１ＭＡＣ左右,即地氟     

相同MAC浓度的安氟醚和异氟醚对脑电图功率谱的影响

２４例 ２０～５０岁、ＡＳＡⅠ级、行择期外科手术的患者，随机分成两组：安氟醚组和异氟醚组。不用术前药，麻醉诱导以静脉硫喷妥钠５ｍｇ／ｋｇ、阿曲库胺０．６～０．７ｍｇ／ｋｇ。单纯吸入安氟醚或异氟醚维持全麻。气管插管后控制呼吸，维持呼气末二氧化碳分压（ＰＥＴＣＯ２）４．２７。４．９３ｈｐａ。以ＴＯＦ监测肌松，间断给予阿曲库胺 １０～１５ｍｇ，维持Ｔ４／Ｔ１＜２５％。采用 ＦＰ１－Ａ１、ＦＰ２－Ａ２双导联监护脑电，验证呼气末麻醉药浓度在 ０． ５、０．８、１． ０、１． ３和 １．５ ＭＡＣ时的脑电功率谱、９５％边缘频率（ＳＥＦ）和中心频率（ＭＰＦ）改变。结果发现，随ＭＡＣ增加脑电功率谱表现出波增加，α和β波减少，而ＳＥＦ、ＭＰＦ值随ＭＡＣ增加而减少的改变呈负性线性关系，ｒ＝－０．９５。提示脑电功率谱、ＳＥＦ和ＭＰＦ在评价全麻深度上有一定意义。     

七氟烷全凭吸入麻醉用于小儿腭裂手术的临床观察

目的：观察七氟烷复合氧化亚氮全凭吸入麻醉用于小儿腭裂手术的临床效果。方法：选40例按美国麻醉医师学会（American Society of Anesthesiologiests,ASA）身体分级为I～II级的腭裂手术患儿,年龄1.5～4岁,随机分为两组。K组：给予氯胺酮5～8mg/kg＋丙泊酚1.5mg/kg＋维库溴铵0.1～0.15mg/kg诱导插管,术中丙泊酚5～10mg/（kg·h）麻醉维持。S组：给予七氟烷8%面罩吸入＋维库溴铵0.1～0.15mg/kg缓慢静注诱导,术中吸入七氟烷及氧化亚氮和氧气,氧化亚氮1L/min、氧气1L/min,七氟烷1.2～1.5MAC（3%～4%）维持麻醉。根据术中血流动力学状况和手术刺激程度,适当调控麻醉深度。采用SPSS11.0软件包进行统计。结果：两组诱导插管均顺利。K组诱导后患儿心率显著增快（P〈0.01）、血压下降（P〈0.05）,插管及术中剥离腭瓣时仍保持较快心率（P〈0.01）,与S组比较有显著差异（P〈0.01）。S组在诱导后患儿心率、血压有所下降（P〈0.05）,但插管和术中心率血压基本保持平稳。术后S组患儿自主睁眼和拔管的时间显著早于K组（P〈0.05）。结论：七氟烷复合氧化亚氮麻醉能较舒适、平稳地满足小儿腭裂手术要求。     

Changes in heart rate variability in sevoflurane and nitrous oxide anesthesia: effects of respiration and depth of anesthesia

STUDY OBJECTIVE: To quantify the effects of sevoflurane on autonomic nerve function by analyzing changes in heart rate (HR) variability in sevoflurane anesthesia; and to investigate the effects of anesthetic depth and apnea on HR variability. DESIGN: Prospective study. SETTING: Operating room (OR) of a university medical center. PATIENTS: 7 ASA physical status I and II patients scheduled for elective surgery. INTERVENTIONS: Patients were premedicated with ranitidine 150 mg. Anesthesia was induced with thiopental sodium 4 mg/kg intravenously (IV) and succinylcholine 1 mg/kg IV, and maintained with nitrous oxide (N(2)O) 67% and sevoflurane in oxygen. Patients were ventilated mechanically at a rate of 15 breaths/min. MEASUREMENTS: R-R interval of electrocardiography (ECG), electroencephalogram (EEG), noninvasive arterial blood pressure (BP), and end-tidal sevoflurane concentration were recorded. Measurements were performed 1) after patients arrived at the OR and were placed in the supine position, 2) a stable period after inhalation of 2% sevoflurane, and 3) following the appearance of an isoelectric EEG at a higher concentration of sevoflurane. At times 2) and 3), data were recorded during mechanical ventilation and during apnea. MAIN RESULTS: There were decreases in both the low-frequency (LF; 0.04 to 0.15 Hz) and high-frequency (HF; 0.15 to 0.4 Hz) components of HR variability during anesthesia compared with the awake state. HF decreased during apnea at 2% sevoflurane, but LF did not change. Neither LF nor HF changed in response to the absence or presence of respiration during isoelectric EEG. CONCLUSIONS: Autonomic nerve activity was attenuated by sevoflurane. Parasympathetic input to the heart by respiration was markedly suppressed following the appearance of isoelectric EEG.     

Concentrations of sevoflurane with and without nitrous oxide to block vasomotor reflexes to incision (MACBVR)

The minimum alveolar concentration of an anesthetic that blocks the skin vasomotor reflex to surgical incision (MACBVR) for sevoflurane was determined in 37 patients aged 30-60 years scheduled for laparotomies with or without nitrous oxide. Thirty seven patients were randomly allocated to one of the two groups: a sevoflurane group and a sevoflurane/N2O (50 vol%) group. The skin blood flow of the finger tip was measured using a laser Doppler flowmeter. Anesthesia was induced with sevoflurane and N2O and tracheal intubation was facilitated with vecuronium 0.1 mg.kg-1. Predetermined end tidal concentrations of sevoflurane and N2O were maintained for at least 15 min before incision. The MACBVR values of sevoflurane in O2 and in the presence of 50% N2O were 3.07% and 1.63%, respectively. The MACBVR level in the total anesthetic MAC multiple was 1.75 MAC for sevoflurane alone and the value decreased to 1.43 MAC when 50% N2O was used. There were no relations between the amplitude of the reduction in skin blood flow and the changes of hemodynamic variables in each group. However, the changes in SBP and HR at incision were significantly suppressed by addition of N2O (changes in SBP and HR: 41.6 +/- 20.4 mmHg and 35.4 +/- 12.5 bpm in the sevoflurane group vs. 24.6 +/- 10.2 mmHg and 18.1 +/- 9.5 bpm in the sevoflurane/N2O group, P < 0.01). The results suggest that N2O is useful to suppress adrenergic responses to a surgical stimulus during sevoflurane anesthesia.     

A rapid increase in the inspired concentration of desflurane is not associated with epileptiform encephalogram

The large inspired concentration of sevoflurane (S) during mask induction of anesthesia can induce epileptiform electroencephalogram (EEG) associated with tachycardia. Tachycardia is also seen when the concentration of desflurane (D) is abruptly increased. It is not known whether this is associated with epileptiform EEG similar to S. We studied EEG and heart rate (HR) during rapidly increased concentrations of S or D in 31 females during the postintubation period of anesthesia. Anesthesia was induced with propofol and remifentanil, and the tracheas were intubated. Patients were randomized to receive either S or D in nitrous oxide-oxygen mixture after intubation, at a small dose first. After 10 min, S or D vaporizer was advanced to the highest reading of the vaporizer (7% for S, 18% for D) for 5 min. HR and EEG were recorded. Epileptiform EEG activity was recorded in eight of 15 patients in group S and in none in group D (P < 0.05). HR increased in both groups. In group S, HR increased gradually and the highest HR value was 84 bpm at 5 min after the increase in sevoflurane concentration. In group D, HR increased to 93 bpm 2 min after the increase in desflurane concentration (no significant difference, S versus D). A rapid increase in the concentration of S frequently induces epileptiform EEG during normoventilation. Tachycardia during increasing concentrations of D is not associated with epileptiform EEG. IMPLICATIONS: A rapid increase in the concentration of sevoflurane induces epileptiform encephalogram (EEG) with tachycardia. A rapid increase in the concentration of desflurane also induces tachycardia but is not associated with epileptiform EEG.     

Effects of nitrous oxide on spectral entropy of the EEG during surgery under balanced anaesthesia with sufentanil and sevoflurane

BACKGROUND: Spectral entropy of the electroencephalogram (EEG) has been proposed to monitor anaesthetic depth. We investigated the effect of nitrous oxide on response (RE) and state entropy (SE) of the EEG during lumbar disc surgery under anaesthesia with sufentanil and sevoflurane. METHODS: In an open study, anaesthesia was induced with propofol and sufentanil, and maintained with 2% end-tidal sevoflurane concentration in air/oxygen (FiO2 = 0.4) in 25 patients. During surgery, nitrous oxide was randomly administered either at 0 or at 60% end-tidal concentration in 10 (control group) and 15 patients (nitrous oxide group), respectively. RE and SE were recorded at 2.5 min intervals for 10 min before randomization and for 25 min either continuously (control) or after achieving the target nitrous oxide concentration. RESULTS: Two patients who received nitrous oxide were excluded from statistical analysis because of protocol violation. Nitrous oxide provoked a significant decrease in RE and SE from 46.2 +/- 11.1 and 44.3 +/- 11.1 to a lowest value of 27.8 +/- 8.3 and 27.1 +/- 8.9, respectively. The decrease in entropy persisted during the 25 min recording period. CONCLUSIONS: Addition of nitrous oxide during balanced anaesthesia with sufentanil and sevoflurane provokes a decrease in response and state entropy of the EEG during lumbar disc surgery.     

Effect of xenon on catecholamine and hemodynamic responses to surgical noxious stimulation in humans

STUDY OBJECTIVE: To determine the effect of xenon in combination anesthesia with sevoflurane on the catecholamine and hemodynamic responses to surgical noxious stimulation in humans. DESIGN: Randomized study. SETTING: A university hospital. PATIENTS: This study involved 32 female ASA physical status I and II patients, age 20-58 years, scheduled for abdominal hysterectomy. INTERVENTIONS: Patients were randomly divided into 4 groups: group X50-S1.5, 50% xenon and 1.5% sevoflurane; group X70-S1.5, 70% xenon and 1.5% sevoflurane; group G70-S1.5, 70% nitrous oxide and 1.5% sevoflurane; and group S2.8, 2.8% sevoflurane. No premedication was administered to the patients, and anesthesia was induced by administration of sevoflurane in oxygen and 0.10 to 0.15 mg/kg of vecuronium. After tracheal intubation, the combination of anesthetics was started, and skin incision was performed after equilibration for more than 15 minutes. MEASUREMENTS: Systolic blood pressure and heart rate (HR) were recorded, and the plasma concentrations of norepinephrine, epinephrine (E), and dopamine were measured 0, 2.5, 5, 7.5, 10, 12.5, and 15 minutes after skin incision. MAIN RESULTS: The maximal increase in the E concentration and the values of the area under the curve for E were significantly smaller in the X50-S1.5 and X70-S1.5 groups compared with that in the S2.8 group (P<0.05). At 1 minute after incision, the HR in X50-S1.5 was significantly lower than those in G70-S1.5 and S2.8 groups and the HR in X70-S1.5 was lower than that in S2.8 group (P<0.01). The systolic blood pressure in S2.8 group at 1 minute was significantly higher than those of other groups (P<0.01). CONCLUSION: Combination anesthesia using xenon and sevoflurane suppresses the plasma E concentration and hemodynamic response after skin incision more effectively than sevoflurane anesthesia alone.     

Bispectral EEG index monitoring of high-dose nitrous oxide and low-dose sevoflurane sedation

This single-blind controlled clinical study characterized the effects of 30-70% nitrous oxide (N2O) and 0.2-0.8% sevoflurane conscious sedation on quantitative electroencephalographic (EEG) readings of 22 healthy dental students as measured by the bispectral index (BIS). The study verified the 2 previously published BIS/N2O investigations showing no correlation between N2O dosage up to 70% and BIS. Observer's Assessment of Alertness and Sedation scores (OAA/S), however, correlated well with increasing doses of N2O from approximately 35 to 70%. A near linear dose-response relationship was established between OAA/S and end tidal (ET) sevoflurane concentrations of 0.4-0.7%. Only at the highest level of end tidal sevoflurane recorded, 0.7%, was statistically significant BIS depression seen. Subjects evaluated the acceptability of the sedative effect of the 2 gases, showing a slight preference for N2O. Comparable partial anterograde amnesia and sedation (OAA/S) were produced by both agents in administered concentrations of 40-70% N2O and 0.6-0.8% sevoflurane. Female subjects exhibited better memory and significantly less amnesia than males. No statistically significant changes occurred in any of the monitored vital signs. EMG readings demonstrated a statistically significant difference from control values only at the highest, 0.7%, ET concentration of sevoflurane. BIS does not appear useful for evaluating the level of nitrous oxide sedation in the dental setting but may have some value in assessing depth of sedation at deeper levels of sevoflurane sedation.     

七氟醚与丙泊酚麻醉对心内直视手术患者应激反应的影响

目的比较七氟醚吸入麻醉与丙泊酚静脉麻醉对心内直视手术患者CPB期间应激反应的影响。方法择期行心脏直视手术患者40例,ASAⅡ或Ⅲ级,随机均分为七氟醚组(S组)和丙泊酚组(P组)。记录诱导前(T0)、气管插管后5min(T1)、CPB后30min(T2)、CPB结束(T3)、术毕(T4)MAP、HR、BIS及血浆促肾上腺皮质激素(ACTH)和皮质醇(Cor)含量。结果与T0时比较,T1时两组MAP、BIS、ACTH、Cor均降低(P<0.05),T2～T4时ACTH、Cor均明显升高(P<0.01)。T2、T3时P组MAP、BIS、ACTH、Cor显著高于S组(P<0.05)。结论心内直视手术CPB期间七氟醚吸入麻醉较之丙泊酚静脉麻醉可显著降低机体应激反应。     

The effects of nitrous oxide on the auditory evoked potential index during sevoflurane anaesthesia

We have studied the effects of nitrous oxide on the auditory evoked response index (AAI-index) derived from the A-line monitoring device during sevoflurane anaesthesia in 21 patients undergoing minor ambulatory surgery. During sevoflurane anaesthesia with an AAI-index < 30, the addition or withdrawal of nitrous oxide in a concentration of 66% end tidal did not show any linear dose dependent change in AAI-index . However, comparing nitrous oxide > 40% to nitrous oxide < 10% end tidal concentration the AAI-index did decrease, p < 0.05. The AAI-index is either non-linear at deeper anaesthetic levels or is insensitive to the anaesthetic effects of nitrous oxide in terms of MAC-multiples.