Preoperative metoprolol improves cardiovascular stability and reduces oxygen consumption after thoracotomy

Background : Increased sympathetic activity perioperatively and associated cardiovascular effects play a central role in cardiovascular complications. High thoracic epidural blockade attenuates the sympathetic response, but even with complete pain relief, haemodynamic and endocrine responses are still present. Beta–adrenoceptor blockade is effective in situations with increased sympathetic activity. This study was designed to evaluate the perioperative haemodynamic effect of preoperative βblockade and its influence on the haemodynamic aspects of the surgical stress response.
Methods : Thirty–six otherwise healthy patients undergoing elective thoracotomy for lung resection were randomised doubleblinded to receive either 100 mg metoprolol or placebo preoperatively. Anaesthesia was combined high thoracic epidural block and general anaesthesia. The epidural analgesia was continued during recovery. Patients were monitored with ECG, pulse oximetry, invasive haemodynamic monitoring, arterial blood gases and electrolytes.
Results : After induction of anaesthesia the mean arterial pressure (MAP) decreased in both groups, and decreased further in the placebo group after initiation of the epidural block. The heart rate (HR) was slightly less throughout the observation period after metoprolol. Peroperatively, the only difference in measured haemodynamics was a marginally higher MAP after metoprolol. Postoperative cardiac index (CI) was lower with a lower variability and cardiac filling pressures were slightly higher in the metoprolol group. The oxygen consumption index was higher after placebo throughout the observation period, with no difference in the oxygen delivery.
Conclusion. We found that preoperative β–blockade during combined general anaesthesia and high thoracic epidural blockade stabilised perioperative HR and CI and decreased total oxygen consumption.     

Effect of thoracic epidural etidocaine 1.5% on somatosensory evoked potentials, cortisol and glucose during cholecystectomy

The effect of thoracic (T7-8) epidural etidocaine 1.5%, 9 ml, and continuous per- and postoperative epidural infusion of etidocaine 1.5%, 4 ml/h, on early (less than 500 ms) somatosensory evoked potentials (SEPs), and cortisol and glucose in plasma during cholecystectomy, was examined in ten patients. Spread of analgesia (pin-prick) was T3 (T1-T3) to L2 (T11-L3) 35 min after injection of etidocaine, and T3 (T2-T4) to T12 (T8-L4) 3 h after surgical incision (median (range)). Before operation, epidural etidocaine had no significant effects on peak-to-peak amplitude of SEPs to electrical stimulation at the L1, T10 or T6 dermatomal level (P greater than 0.09). SEPs were abolished in only two patients at T6, and no patient had SEPs abolished at T10 or L1. The plasma concentrations of cortisol and glucose were significantly increased 20 min after surgical incision and remained increased throughout the study. No correlation was found between the block-induced decrease in the peak-to-peak amplitude at T6 or T10 and increase in plasma cortisol, except for a negative correlation at T10 and the initial increase in cortisol (Rs = 0.72, P = 0.03). In conclusion, thoracic epidural administration of 9 ml of etidocaine 1.5% does not provide total afferent somatic blockade assessed by SEP and the stress response to cholecystectomy.     

Clinical experience with minimal flow xenon anesthesia

Xenon is a more potent anesthetic than nitrous oxide, and gives more profound analgesia. This investigation was performed to assess the potential of xenon for becoming an anesthetic inspite of its high manufacturing cost. Seven ASA I—-II patients undergoing cholecystectomy (n = 4), hernia repair (n = 2), or mammoplasty (n=l) were studied. Denitrogenation by 15–20 min of oxygen breathing under propofol anesthesia was followed by fentanyl–supplemented xenon anesthesia administered via an automatic minimal flow system which held the oxygen concentration at 30%. Xenon anesthesia lasted 76–228 min and 8–14 1 of xenon (ATPD) was used, of which 5.6–8.1 1 was expended during the first 15 min. Anesthesia appeared to be satisfactory, and the patients woke up rapidly after xenon was discontinued. The automatic system made minimal flow xenon anesthesia easy to administer, but nitrogen accumulation is still a problem. Assuming a xenon price of 10 US $ per litre, the average cost for xenon was about 65 US $ for the first 15 min and then about 25 USS for each subsequent hour of anesthesia.     

静注加肌注曲马多防治硬膜外麻醉期间寒战反应的研究

目的　观察曲马多防治硬膜外麻醉期间寒战反应时两种用药方法的临床效果。　方法硬膜外麻醉手术期间发生寒战的 6 0例成年患者 ,当出现寒战分级达 2～ 3级时 ,用室温下盐酸曲马多 1mg kg加氟哌啶 2 .5mg缓慢静脉推注 ,随机分成二组 :研究组 (R组 )与对照组 (C组 ) ,每组各 30例 ;R组在 5min内用上述同样药物和剂量予以肌内注射 ,C组以生理盐水 2ml肌内注射。观察寒战的治疗效果及 6h内寒战复发率。　结果　两组均于静注曲马多后 3min内起效 ,所有病人寒战反应均得到缓解 ,6h内R组均无寒战反应复发 ,C组有 5例再次出现寒战达 2级以上 ,给予追加首次量的 1 2后缓解 ,两组间差异有显著性 (P <0 .0 5 )。　结论　静注加肌注曲马多和氟哌啶可更有效地防治硬膜外麻醉期间的寒战反应。     

全麻复合硬膜外麻醉患者林格氏溶液的容量动力学

目的 通过确定全麻复合硬膜外时麻醉林格氏溶液的容量动力学模型参数，评价硬膜外复合全麻对晶体液扩容效应的影响。方法择期行肝癌切除术患者20例，随机分为2组：组Ⅰ麻醉诱导前行扩容治疗，组Ⅱ硬膜外复合全麻诱导后行扩容治疗。扩容采用30ml／kg乳酸钠林格氏溶液（LR）恒速输注，30min内输完，输注LR开始后90min内每5min测定血红蛋白（Hb）及红细胞压积（Hct），并记录总尿量及血液动力学数据。用容量动力学数学模型和物质守恒定律处理数据，获得结果。结果 组Ⅱ容量增加量、容量扩张效率、输注结束时液体保留率均高于组Ⅰ（P〈0．05）。一级容量动力学分析结果：组Ⅰ目标容积（V）和清除率（k1）均大于组Ⅱ（P〈0．05）。二级容量动力学分析结果：组Ⅱ的V1、k1、k1均高于组Ⅱ（P〈0．05）。扩容后组Ⅱ的平均动脉压、中心静脉压、心输出量均小于组Ⅰ（P〈0．05）。结论 全麻复合硬膜外麻醉可提高晶体液的容量扩张效率。     

术中输注氨基酸对硬膜外阻滞复合全麻开胸手术患者围术期体温的影响

目的评价术中输注氨基酸对硬膜外阻滞复合全麻食管癌和贲门癌手术患者围术期深部体温和代谢的影响。方法择期食管癌和贲门癌手术患者21例,ASAⅠ或Ⅱ级,随机分为3组(n =7):从麻醉诱导开始至手术结束,分别静脉输注氨基酸混合液240kJ·h-1(AA组)、等容量乳酸钠林格氏液(LR组)、葡萄糖溶液240kJ·h-1(GLU组)。麻醉诱导前至术后2h每5分钟测定鼓膜温度,于麻醉诱导前即刻、手术开始后1h和术后1h检测指尖血糖,采用4分表法评价术后2h内寒战的发生情况,采用间接测热仪测定术前与术后氧耗。结果与麻醉诱导前即刻比较,术后30min LR组和GLU组氧耗降低,AA组氧耗升高(P<0.01),术后2h LR组、GLU组鼓膜温度降低(P<0.05),AA组差异无统计学意义(P>0.05);与LR组和GLU组比较,AA组术后2h内寒战发生例数减少(P< 0.05),术后30min氧耗增多(P<0.05),LR组与GLU组比较差异无统计学意义(P>0.05)。结论硬膜外阻滞复合全麻开胸手术患者术中静脉输注氨基酸可通过提高基础代谢率,缓解围术期深部体温降低,减少术后寒战发生,而输注葡萄糖不产生此效应。     

Does Epidural Analgesia Affect the Rate of Spontaneous Obstetric Lacerations in Normal Births?

The precise relationship between epidural use and genital tract lacerations in normal childbirth is unclear. Data from a clinical trial on measures to lower genital tract trauma in vaginal birth were used for a secondary analysis. The goal was to assess whether epidurals affect the rate of spontaneous obstetric lacerations in normal vaginal births. Maternal characteristics and intrapartum variables were compared in women who did and did not use an epidural in labor, and also in those with and without any sutured lacerations following vaginal birth. Variables that were statistically different in both cases were entered into regression equations for simultaneous adjustment. Epidural use was not an independent predictor of sutured lacerations. Predictors of sutured lacerations included nulliparity, a prolonged second stage, being non-Hispanic white, and an infant birthweight greater than 4000 grams. Elements of midwifery management need further research.     

硬膜外阻滞的镇静作用及其可能机制

目的 通过监测脑电双频指数和心率变异功率谱,评价硬膜外麻醉后对异丙酚镇静催眠剂量的影响,并探讨其可能的机制。方法 50例行全子宫切除病人,随机分为硬膜外利多卡因组（GE,n=15）;硬膜外盐水-静脉利多卡因组（GI=15）;硬膜外盐水-静脉盐水组（GC=20）。硬膜外或静脉给利多卡因 20 min后,连续输注异丙酚至神志消失并记录异丙酚用量。所有病人同时监测脑电双频谱（BIS）、心率变异高频功率谱（HF）、低频功率谱（LF）、心电图和血压。输注异丙酚前抽取桡动脉血 2ml,测定血浆利多卡因浓度。结果 病人意识消失时异丙酚用量分别为GE组（1.22±0.25）mg/kg;GI组（1.62±0.22）mg/kg;GC组（1.85±0.41）mg/kg（GE与GI和GC比,P<0.05）。GE组和 GI组血浆利多卡因浓度分别为 3.04 μg/ml和 2.45 μg/ml,无统计学差异。三组病人意识消失时BIS平均值分别为54.4、57.1、55.3。结论 硬膜外利多卡因阻滞可降低异丙酚用量约35％。其作用机制与利多卡因自硬膜外吸收后的中枢镇静作用无明显关系,而可能与硬膜外阻滞后间接引起中枢兴奋阈值降低有关。     

控制性降压在鼻内窥镜手术中的应用

目的 :观察控制性降压在鼻内窥镜手术中应用的意义。方法 :80例双侧鼻息肉、鼻窦炎患者 ,局麻、鼻内窥镜下行双侧鼻息肉摘除、全筛切除及开放上颌窦自然开口。其中 38例术中控制性降压 (降压组 ) ,另 42例作为对照。结果 :降压组术中出血 (6 1 39± 38 5 2 )ml,对照组出血 (140 12± 81 82 )ml,差异有显著性意义 (P <0 0 1) ;手术时间分别为 (4 9 2 5± 7 0 6 )min和(6 2 4 0± 9 90 )min ,差异有显著性意义 (P <0 0 1)。结论 :控制性降压可明显减少术中出血 ,缩短手术时间。     

Repeated unilateral epidural blockade

Unilateral epidural analgesia occurring in a parturient three times in successive pregnancies is reported. Possible causes are reviewed, and clinical and radiological evidence in support of the most likely explanation are presented.