Isoflurane increases,but sevoflurane decreases blood concentrations of melatonin in women

The blood concentrations of melatonin are elevated by stress-induced sympathetic nerve excitation and are affected by some anesthetics. Isoflurane has an effect to increase sympathetic nerve activity when compared with sevoflurane. This study was performed to investigate the effects of these two anesthetics on the blood concentrations of melatonin. Female patients were anesthetized with either isoflurane or sevoflurane. We obtained blood samples before and 5min after 5% isoflurane (ISO group) or 7% sevoflurane (SEV group) anesthesia. The blood melatonin concentrations during anesthesia in the ISO group increased significantly, from 65 ± 60 to 170 ± 90pg·ml^–l; mean ± SD (P < 0.05), whereas those in the SEV group decreased, from 60 ± 50 to 30 ± 30pg·ml^–l (P < 0.05). In conclusion, isoflurane increases, but sevoflurane decreases blood melatonin concentrations.     

Propofol or sevoflurane anesthesia without muscle relaxants for thymectomy in myasthenia gravis

Background Myasthenia gravis is a challenging clinical condition due to its neuromuscular involvement. We sought to compare two non-muscle relaxant anesthetic techniques in patients undergoing trans-sternal thymectomy, evaluating the intra and postoperative conditions including extubation in the operating room. Methods Eight consecutive myasthenic patients undergoing trans-sternal thymectomy were prospectively randomized into two groups: propofol and sevoflurane. In both groups anesthesia was induced with propofol (2mg. Kg⁻¹) and intubation performed after topical anesthesia of the airway with lignocaine. Anesthesia was maintained in the propofol group (4 patients) with continuous propofol infusion (3–10 mg. Kg⁻¹., hr⁻¹) with oxygen and nitrous oxide and in the sevoflurane group (4 patients), with sevoflurane (end tidal 1–1.5%) in oxygen and nitrous oxide. Fentanyl was used for analgesia in both the groups. Intubating conditions, haemodynamic changes, neuromuscular transmission along with postoperative intensive care unit stay were evaluated. Data were evaluated using ANOVA, Chi-square test and Student'st test. Results Intubating conditions were good in all patients. There were no significant haemodynamic changes. All patients were extubated in the operating room and none had to be re-intubated for postoperative respiratory depression. Neuromuscular transmission showed minimal changes and at the end of the procedure the recovery was complete in all the patients. There were no other significant differences between the two groups studied. Conclusion These two anesthetic techniques allow early extubation of myasthenic patients in the operating room.     

脑电双频指数(BIS)指导七氟醚用于颅内手术麻醉

目的 该文拟探讨脑电双频指数(bispectral index,BIS)指导七氟醚麻醉在颅内手术的可行性.方法 选用40例18～60岁,ASA Ⅰ、Ⅱ级择期行颅内肿瘤摘除术的患者,随机分为指导组(BIS组)和对照组,每组20例.对照组根据同一麻醉医生的临床经验来调整七氟醚的吸入浓度,指导组则通过BIS维持在(55±5)左右来调定七氟醚浓度,记录麻醉期间血压、心率以及BIS的变化,并测量记录2组患者七氟醚的用量.结果 指导组平均动脉压明显高于对照组,但对照组平均动脉压及心率波动幅度较大,指导组的BIS值明显高于对照组,但麻醉过程相对平稳,七氟醚以及镇痛药的用量指导组也明显少于对照组.结论 BIS可为七氟醚用于颅内手术麻醉镇静深度提供量化指标.     

七氟醚吸入麻醉在小儿唇腭裂手术中的应用

目的观察七氟醚吸入麻醉用于小儿唇腭裂手术的麻醉诱导、维持及苏醒的临床效果。方法50例唇腭裂患者，ASAⅠ-Ⅱ，年龄2月-12岁。6岁以下患儿采用七氟醚快速吸入麻醉诱导，七氟醚5—8vd％＋吸入氧6L／min，待疼痛消失后，经口异型管（oral）气管插管；6岁以上患儿静注芬太尼1μg／kg，同时吸入七氟醚5—8vol％＋吸入氧6L／min，待疼痛消失后，经口异型管（oral）气管插管或喉罩（LMA）置入，待麻醉诱导完毕，术者做眶下神经阻滞。术中七氟醚维持2—3vol％，＋吸入氧1-3L／min，保持患者自主呼吸存在。记录睫毛反射消失时间，疼痛反射消失时间，术后苏醒时间，观察幼儿是否合作，诱导期患儿是否合作，有无咳嗽、屏气及喉痉挛，有无术后躁动及恶心呕吐等并发症。记录诱导前、睫毛反射消失时、气管插管时、术中、术毕各时间点MAP、HR、SpO2％、PETCO2的变化。结果睫毛反射消失时间（48．5±13．5）s，疼痛反射消失（147±23．5）s苏醒时间（3．82±1．25）min。6岁以上患儿中2例术中体动，追加异丙酚0．5mg／kg后麻醉平稳。无一例术后恶心呕吐及躁动。插管时MAP和HR稍有增快，插管后恢复诱导前水平，SpO2、PETCO2均无显著改变。结论七氟醚具有气味芬芳，诱导迅速，术中可不需肌松弛剂，麻醉维持平稳，苏醒快，不良反应少，是理想的吸入麻醉剂。     

七氟烷与丙泊酚用于小儿唇腭裂手术诱导比较

目的:比较小儿麻醉用七氟烷吸入诱导和丙泊酚静脉诱导的临床特点。方法:择期手术的患儿30例,美国麻醉医师协会(ASA)Ⅰ-Ⅱ级,随机分为两组:七氟烷(Sev)组和丙泊酚(Pro)组,分别记录诱导至意识消失的时间,和诱导前、诱导时、插管后即时和插管后1分钟的血压、心率、SpO_2,及诱导时躁动、屏气、喉、支气管痉挛、恶心、呕吐等不良反应。结果:两组患儿意识消失的时间没有显著差异,分别为丙泊酚组(35.5±11.7)s;七氟烷组(38.5±11.4)s。两组诱导和插管后血压与诱导前比较均无明显变化,但心率变化两组相差较大。丙泊酚组与诱导前相比心率显著增加(P<0.05);而七氟烷组心率较诱导前明显下降(P<0.05)。发生躁动七氟烷组显著多于丙泊酚组(P<0.05),分别是46%和20%。两组均未见屏气、喉及支气管痉挛和恶心、呕吐等不良反应。结论:两组在麻醉诱导的时间和有效性、安全性上没有差别。但是丙泊酚静脉诱导心率明显增快;七氟烷吸入诱导患儿躁动相对较多。     

Predicted sevoflurane partial pressure in the brain with an uptake and distribution model comparison with the measured value in internal jugular vein blood

Objective. In order to predict the partial pressure of volatile anesthetics in brain tissue, we developed a pharmacokinetic simulation model suitable for real time application. The accuracy of this model was examined by comparing the predicted values against measured values for blood sampled from the internal jugular vein, which was used as a measure of the partial pressure in the brain. Methods. Our model consists of six compartments: alveoli, arterial blood, a group of vessel-rich organs (VRG), muscle, fat, and venous blood. A volatile anesthetic, sevoflurane partial pressure in each compartment were calculated using the parameters of volume, blood flow, and solubility for each tissue as reported in previous studies. Simulated sevoflurane partial pressures in VRG were considered to reflect those in the brain. We studied 11 patients undergoing elective abdominal surgery or mastectomy. Sevoflurane was maintained at a concentration of 3% (by vaporizer setting) for 25 min. Sampling points were at 0 min (before sevoflurane administration) and 1, 2, 4, 9, 16, and 25 min after the start of inhalation. We measured the sevoflurane partial pressure in inspiratory gas (PI_S), in end-expiratory gas (PET_S), in arterial blood (Pa_S), and in internal jugular vein blood (PjS). These values were compared against those for the simulated brain (PB_Ssim). Results. The sevoflurane partial pressures increased, in order from least rapid to most rapid, as follows: Pj_S, PB_Ssim, Pa_S, PET_S, and PI_S. The differences between Pj_S and PB_Ssim were significantly smaller than those between Pj_S and PET_S at all sampling points. PB_Ssim did not differ significantly from Pj_S at any sampling points after 4 min of inhalation, while PET_S differed significantly from Pj_S at all sampling points. Conclusion.We conclude that our model is clinically useful for predicting sevoflurane partial pressure in the brain, assuming that Pj_S reflects the sevoflurane partial pressure in the brain.     

七氟烷复合靶控输注瑞芬太尼用于腹腔镜手术的临床评价

目的评价靶控输注(target controlled infusion,TCI)瑞芬太尼复合吸入七氟烷3种不同配伍剂量用于腹腔镜手术的麻醉效果和麻醉恢复情况。方法选择ASAⅠ~Ⅱ级择期行腹腔镜胆囊切除术或腹腔镜卵巢囊肿切除术45例,随机分为3组,每组15例。3组诱导方式均相同。麻醉维持:A组为瑞芬太尼血浆靶控输注6ng/ml复合吸入0.4MAC(minimal alveolar concentration,肺泡最低有效浓度)七氟烷;B组为瑞芬太尼血浆靶控输注4ng/ml复合吸入0.65MAC七氟烷;C组为瑞芬太尼血浆靶控输注2ng/ml复合吸入1.0MAC七氟烷。观察患者麻醉和术中脑电双频指数(bispectral index,BIS)、平均动脉压(meanarterial pressure,MAP)、心率(heartrate,HR)及术后呼吸恢复时间、睁眼时间、气管导管拔管时间、定向力恢复时间等指标。结果3组病人术中生命体征平稳,无须调整七氟烷和瑞芬太尼的用量。3组术中各时点MAP、HR无统计学差异(P>0.05)。术中各时点BIS值A组明显高于B组和C组,B组明显高于C组(P<0.05)。3组病人在麻醉恢...     

反复吸入七氟烷对幼年大鼠认知功能的影响

目的 评价反复吸入七氟烷对幼年大鼠认知功能的影响.方法 健康雄性SD大鼠108只,25～35日龄,体重90～100 g,随机分为6组(n=18),C1组、C2组和C3组每天同一时间吸入纯氧0.5 L/min,1 h/次,分别吸入1、3、5 d;S1组、S2组和S3组每天同一时间吸入2.3%七氟烷及纯氧0.5 L/min,1 h/次,分别吸1、3、5 d.干预结束后7 d,各组随机取10只大鼠进行水迷宫实验,记录达标所需训练次数、逃避潜伏期及进入盲端次数;其余8只记录神经电生理强直刺激后群峰电位(PS)振幅,计算长时程增强(LTP)诱发成功率.结果 各组大鼠水迷宫实验达标所需训练次数、逃避潜伏期及进入盲端次数差异无统计学意义(P>0.05).与C3组比较,S3组LTP诱发成功率降低(P<0.05);C1组与S1组比较、C2组与S2组比较差异均无统计学意义(P>0.05).结论 反复吸入七氟烷虽可抑制幼年大鼠LTP形成,但抑制程度较轻,对认知功能无明显影响.     

七氟醚麻醉下瑞芬太尼抑制小儿气管插管心血管反应的半数有效血浆靶浓度

目的 确定七氟醚麻醉下瑞芬太尼抑制小儿气管插管心血管反应的半数有效血浆靶浓度(Cp<50).方法 择期全麻手术患儿,年龄2～5岁,ASA Ⅰ或Ⅱ级.初始七氟醚吸入浓度为8%,氧流量3 L/min,待患儿意识消失后调整七氟醚吸入浓度,使呼气末七氟醚浓度为2.5%(1 MAC),2 min后采用Minto药代动力学模型靶控输注瑞芬太尼,10 min后进行气管插管.瑞芬太尼血浆靶浓度按序贯法确定,瑞芬太尼血浆靶浓度从6μg/L开始,相邻浓度的比值为1.2,气管插管心血管反应的标准:插管后2 min内MAP和/或HR较插管前升高≥15%.结果 瑞芬太尼抑制气管插管心血管反应的Cp50为3.6μg/L,95%可信区间为3.1～4.0μg/L.结论 七氟醚1 MAC麻醉下瑞芬太尼抑制小儿气管插管心血管反应的Cp50为3.6 μg/L,95%可信区间为3.1～4.0μg/L.