Refractive indices for volatile anesthetic gases: Equipment and method for calibrating vaporizers and monitors

Objective. The objective of our study was to establish the refractive indices and the virial coefficients of the volatile anesthetic vapors. These indices and coefficients will allow refractometry to be used by manufacturers to produce accurate calibration, without requiring expensive high-precision calibration gases.Methods. We used a precision refractometer to measure the refractive indices for five volatile anesthetic vapors. We prepared our calibration gases by mixing a gravimetrically calibrated amount of liquid agent with a constant gas flow.Results. The refractive indices for the volatile anesthetic vapors are 1,603.2 for halothane, 1,540.4 for enflurane, 1,563.3 for isoflurance, 1,538.3 for sevoflurane, and 1,211.7 for desflurane. The maximum theoretical error in our measurements, due to all sensors and all uncertainty in our measurement of apparatus and physical constants, is ±0.56% of the reading (±0.70% for desflurane).Conclusions. If refractometry replaced calibration gases in cylinders, as a calibration standard, manufacturers might avoid errors that now occur because calibration gases manufactured by numerous companies seem to differ. We propose that our values serve as an interim database.     

Escasa notificación de las dosis de los antiinfecciosos de uso sistémico en los casos clínicos comunicados a la Revista Española de Anestesiología y Reanimación

ObjectiveTo describe the frequency of dose notification of antiinfectives for systemic use in clinical cases published in Revista Española de Anestesiología y Reanimación.Material and methodReview of individualized clinical cases published in the sections «Clinical case» or «Letter to the Editor» of the above mentioned journal from year 2010 to 2012, and identification of the drugs and their therapeutic regimens cited in such publications, being dose notification the main variable. Drugs have been classified according to the Anatomical Therapeutic Chemical Classification System.ResultsOne thousand one hundred and thirty-five drugs cited 1,317 times were identified in 167 articles describing the clinical pictures of 182 patients, 73 of the citations (5.6%) regarding to drugs belonging to group J (Antiinfectives for systemic use) which were divided into perioperative prophylaxis (n = 15) and active treatment (n = 58). Doses were scarcely notified for group J drugs as a whole (27.4%), but especially for active treatment (17.2%) compared to perioperative prophylaxis (66.7%), percentage which was similar to those more classical anesthetic drugs (fentanyl: 86.6%; remifentanil: 70.5%; sevoflurane: 78%; propofol: 79%; rocuronium:79.6%; cisatracurium: 68.4%) or even for antiemetics (ondansetron: 92.3%; dexamethasone: 84.6%).ConclusionsQuality of case reports could be improved by including dose notification for antiinfective agents.     

全身麻醉药物对老年患者术后早期认知功能障碍的影响

目的 探讨不同全身麻醉药物对老年患者术后早期认知功能障碍的影响.方法 选择我院2010年8月-2012年6月实施全身麻醉患者60例,随机分为3组,分别给予3组患者C泊酚、七氟醚及咪达唑仑维持麻醉,分析临床结果.结果 3组患者组间苏醒及拔管时间相比较,A组和C组比较差异无统计学意义（P＞0.05）,但B组却短于A组、C组,差异有统计学意义（P＜0.05）.3组患者麻醉前MoCA及MMSE评分差异均无统计学意义（P＞0.05）.与麻醉前相比,A、C两组患者麻醉后6h、1d及3d的MoCA及MMSE评分差异有统计学意义（P＜0.05）;B组麻醉前后MoCA及MMSE评分差异无统计学意义（P＞0.05）.同B组相比,其余两组麻醉后各时间点的MoCA及MMSE评分差异均有统计学意义（P＜0.05）.结论 3种麻醉药物在老年患者全身麻醉中均能保证安全高效的麻醉作用,其中七氟醚对患者术后早期认知功能障碍影响明显小于C泊酚及咪达唑仑,值得推广使用.     

The Effects of Desflurane on Human Platelet Aggregation In Vitro

In view of the possible antiplatelet effects of general anesthetics, we investigated the in vitro effects of desflurane, a new inhalation agent, on platelet aggregation. For 15 patients who underwent elective operations, blood was sampled with desflurane induction before and after anesthesia but prior to surgery so that platelet aggregation in the drawn blood could be tested before desflurane anesthesia and again after exposure to the anesthetic. Platelet aggregation was measured with a whole-blood aggregometer. Adenosine diphosphate (ADP), collagen, and ristocetin were used as aggregating agents. Our results showed that aggregation in response to ADP, collagen, or ristocetin was not inhibited in patients who received desflurane anesthesia. This study with an in vitro model showed that desflurane had no influence on platelets in clinically relevant doses.     

Electroencephalogram spectral edge frequency,lower esophageal contractility,and autonomic responsiveness during general anesthesia

Both the electroencephalogram (EEG) spectral edge frequency (SEF) and lower esophageal contractility (LEC) indices have been reported to be useful indicators of anesthetic depth. We designed a prospective study to evaluate the relationship between changes in these two variables and objective measurements of physiologic responsiveness to surgical stress (i.e., changes in hemódynamic variables and plasma levels of norepinephrine, epinephrine, total catecholamines, and vasopressin). Eighty-nine consenting adult males undergoing radical prostatectomy procedures under a standardized general anesthetic technique were studied according to a randomized, single-blinded protocol. General anesthesia was induced with 30 µg/kg intravenous (IV) alfentanil, 2.5 mg/kg IV thiopental, and 0.1 mg/kg IV vecuronium, and subsequently maintained with 0.5 µg/kg/min alfentanil, nitrous oxide (N₂O) 67% in oxygen, and 0.8 µg/kg/min vecuronium. Following retropubic dissection, 81 patients (92%) manifested acute hypertensive responses, with mean arterial pressure increasing from 90±14 to 122±14 mm Hg (mean ± SD). This acute hypertensive response was treated with one of three different treatment modalities (20 to 60 µg/kg IV alfentanil, 0.5 to 2.0% inspired isoflurane, or 0.05 to 0.15 mg/kg IV trimethaphan) to return the mean arterial pressure to within 10% of the preincisional (baseline) value within 5 to 10 minutes. Although the mean arterial pressure, heart rate, and plasma levels of catecholamines and vasopressin significantly increased following the surgical stimulus, and decreased after adjunctive therapy, the EEG-SEF and LEC index (LECI) values did not significantly change during these study intervals. Furthermore, using a logistic regression analysis, we observed that preincision EEG-SEF and LECI values could not predict whether patients would manifest a hypertensive response. Therefore, the EEG-SEF and LECI were unreliable indicators of anesthetic depth.This study was supported in part by a grant from the Ambulatory Anesthesia Research Foundation, Los Altos, CA. (Dr White is a member of the Board of Directors.)The authors would like to thank Dan Kuni (Baxter Healthcare) for his assistance in obtaining the equipment used to perform the study; Vinod Kothapa, MD, for his valuable assistance with the anesthetic management of the study patients; Alex K. Mills, MD, for his assistance with the EEG interpretation; and Steven A. Bai, PhD, for his assistance with the plasma alfentanil analyses.     

麻醉药物选择对鼻、咽腔手术患者苏醒期躁动的影响

目的:探讨不同麻醉用药方案对全麻下行鼻、咽腔手术患者苏醒期躁动情况的影响。方法:将106例拟于全身麻醉下行鼻、咽腔手术的患者随机分为A组和B组。麻醉诱导:A组患者静脉注射瑞芬太尼0.8μg/kg,丙泊酚2 mg/kg和罗库溴铵0.6 mg/kg;B组静脉注射芬太尼2μg/kg,丙泊酚2 mg/kg和维库溴铵0.1 mg/kg。麻醉维持:A组患者吸入七氟醚1~1.5MAC、持续静脉泵注瑞芬太尼0.08~0.15μg/(kg.min)和根据需要分次静脉注射罗库溴铵0.3 mg/kg;B组患者吸入异氟醚1~2 MAC、静脉注射芬太尼1μg/kg和根据需要分次静脉注射维库溴铵0.04 mg/kg。观察并记录患者从停止吸入麻醉药到自主呼吸恢复、拔除气管导管以及认知功能恢复的时间;观察并记录患者麻醉恢复期躁动的情况及发生率。结果:A组患者躁动发生率明显低于B组(P0.001);A组患者自主呼吸恢复时间、气管导管拔管时间以及认知功能恢复时间均明显短于B组(P0.01)。结论:采用七氟醚、瑞芬太尼和罗库溴胺的麻醉方法能够减少全麻患者苏醒期躁动的发生率并缩短麻醉苏醒时间。     

p38MAPK信号转导通路在七氟烷后处理减轻乳鼠心肌细胞缺氧复氧损伤中的作用

目的 评价p38丝裂原活化蛋白激酶(p38MAPK)信号转导通路在七氟烷后处理减轻乳鼠心肌细胞缺氧复氧损伤中的作用.方法 健康新生SD大鼠,日龄1～3 d,处死后取心室肌组织,培养心肌细胞,随机分为7组:对照组(C组)于CO2培养箱中持续培养3 h;缺氧复氧组(AR组)细胞缺氧2 h,复氧1 h;七氟烷后处理组(SP组)细胞缺氧2 h,复氧开始即刻更换为3%七氟烷饱和的DMEM培养液,孵育20 min,再更换为无血清DMEM培养液,继续复氧40 min;七氟烷后处理+SB203580组(SP+SB组)于七氟烷后处理同时加入SB203580(p38MAPK特异性抑制剂)至5 μmol/L,孵育20 min;七氟烷后处理+二甲亚砜组(SP+DMSO组)于七氟烷后处理同时加入0.1%DMSO,孵育20 min;SB203580组(SB组)于复氧开始时加入SB203580至5 μmol/L,孵育20 min;二甲亚砜组(DMSO组)于复氧开始即刻加入0.1%DMSO,孵育20 min.各组细胞分别接种于24孔培养板(1 ml/孔)、35 mm培养皿(5 mlnd/皿)和50 ml培养瓶(8 ml/瓶)中,每组12孔、6皿和6瓶.于复氧结束后,采用比色法测定细胞培养液乳酸脱氢酶(LDH)活性;采用台盼蓝排斥实验测定细胞存活率;采用流式细胞仪测定细胞凋亡率;采用Western blot法测定磷酸化p38MAPK(p-p38MAPK)表达水平.结果 与C组比较,其余各组LDH活性升高,细胞存活率降低,细胞凋亡率升高,AR组、SP组、SP+SB组、SP+DMSO组和DMSO组p-p38MAPK表达上调(P<0.05);与AR组比较,SP组、SP+SB组和SP+DMSO组LDH活性降低,细胞存活率升高,细胞凋亡率降低,p-p38MAPK表达上调(P<0.05);与SP组比较,SP+SB组、SB组和DMSO组LDH活性升高,细胞存活率降低,细胞凋亡率升高,p-p38MAPK表达下调(P<0.05).结论 七氟烷后处理可通过激活p38MAPK信号转导通路减轻乳鼠心肌细胞缺氧复氧损伤.     

PI3K-Akt-eNOS信号转导通路在七氟醚后处理减轻大鼠心肌缺血再灌注损伤中的作用

目的 评价磷酯酰肌醇-3-激酶/丝氨酸-苏氨酸激酶/内皮型一氧化氮合酶(PI3K-Akt-eNOS)信号转导通路在七氟醚后处理减轻大鼠心肌缺血再灌注损伤中的作用.方法 健康雄性Wistar大鼠50只,体重250 ～ 280 g,2～3月龄,采用随机数字表法,将大鼠随机分为5组(n=10):假手术组(S组)、缺血再灌注组(I/R组)、七氟醚后处理组(Spo组)、七氟醚后处理+二甲基亚砜组(Spo+D组)和七氟醚后处理+ PI3K特异性抑制剂LY294002组(Spo+L组).I/R组、Spo组、Spo+D组和Spo+L组采用结扎左冠状动脉前降支30 min的方法制备心肌缺血再灌注损伤模型.Spo组、Spo+D组和Spo+L组进行七氟醚后处理:再灌注前1 min使呼气末七氟醚浓度达到2.5％～3.0％,持续吸入5min; Spo+L组于再灌注前5min静脉注射LY294002 0.3 mg/kg,Spo+D组给予等容量二甲基亚砜.再灌注120 min时,每组取10只大鼠,采集动脉血样,检测血清LDH、CK-MB的活性和cTnI浓度.每组处死5只大鼠,取心脏,分离左心室,计算心肌梗死体积;每组处死5只大鼠,取心肌组织,测定Akt、磷酸化Akt(p-Akt)、eNOS和磷酸化eNOS(p- eNOS)的表达,计算p-Akt表达与Akt表达的比值(p-Akt/Akt)和p-eNOS表达与eNOS表达的比值(p-eNOS/eNOS).结果 与S组比较,其余4组血清CK-MB、LDH的活性、cTnI浓度、心肌梗死体积升高,心肌p-Akt/Akt和p-eNOS/eNOS升高(P＜0.05或0.01);与I/R组比较,Spo组和Spo+D组血清CK-MB、LDH的活性、cTnI浓度和心肌梗死体积降低,心肌p-Akt/Akt和p-eNOS/eNOS升高(P＜0.05或0.01),Spo+L组上述指标差异无统计学意义(P＞0.05);Spo组与Spo+D组上述指标比较差异无统计学意义(P＞0.05).结论 PI3K-Akt-eNOS信号转导通路介导了七氟醚后处理减轻大鼠心肌缺血再灌注损伤作用.     

七氟烷后处理对大鼠肺缺血再灌注损伤的影响

目的 探讨七氟烷后处理对大鼠肺缺血再灌注(IR)损伤的影响及其可能机制.方法 健康SPF级雄性SD大鼠96只,体重270～330 g.随机分为4组(n=24):假手术组(S组)、缺血再灌注组(IR组)、七氟烷预处理组(SPr组)和七氟烷后处理组(SPo组).采用阻断左肺门45 min后再灌注的方法 制备大鼠单肺原位IR模型.SPr组吸入七氟烷,呼气末浓度2.1%,30 min后制备肺IR模型;SPo组于再灌注前即刻吸入七氟烷30 min,呼气末浓度2.1%.分别于再灌注30 min、1、2、4 h时测定支气管肺泡灌洗液(BALF)肿瘤坏死因子α(TNF-α)、白细胞介素1(IL-1)、IL-6浓度,并进行白细胞分类计数,计算多形核白细胞占白细胞的百分比(PMN百分比),同时测定肺组织TNF-α、IL-1、IL-6含量及细胞凋亡指数,光镜、电镜下观察肺组织病理学结果 并行损伤评分.结果 与S组比较,IR组肺组织和BALF中TNF-α、IL-1、IL-6水平、细胞凋亡指数、白细胞计数、PMN百分比和肺组织损伤评分均升高,SPr组和SPo组肺组织TNF-α、IL-1、IL-6含量升高(P<0.01);与IR组比较,SPr组和SPo组上述指标均降低(P<0.05或0.01);SPr组与SPo组各指标差异无统计学意义(P>0.05).结论 七氟烷后处理可减轻大鼠肺IR损伤,效果与其预处理无差异,其肺保护作用的机制可能与降低肺组织炎性反应,抑制细胞凋亡有关.     

七氟醚预处理对大鼠脊髓缺血再灌注损伤的影响及自噬在其中的作用

目的 评价七氟醚预处理对大鼠脊髓缺血再灌注损伤的影响及自噬在其中的作用.方法 成年雄性SD大鼠45只,体重420～450 g,采用随机数字表法分为5组(n=9):对照组(Con组)、脊髓缺血再灌注组(I/R组)、七氟醚预处理组(Sevo组)、特异性自噬抑制剂3-甲基腺嘌呤组(3-MA组)和3-MA+七氟醚预处理组(3-MA+ Sevo组).I/R组胸主动脉球囊阻断+体循环低血压制备大鼠脊髓缺血再灌注模型,Sevo组于缺血前24h时吸入3.4％七氟醚2h,3-MA组和3-MA+ Sevo组分别于再灌注即刻和吸入七氟醚前15 min时鞘内注射20出3-MA(10 mmol/L).于再灌注24h时采用神经功能缺陷评分(NDS评分)法评价大鼠神经功能,随后处死取脊髓,Western blot法检测LC3B、Beclin 1、Bcl-2蛋白的表达水平.结果 与Con组比较,I/R组脊髓LC3B、Beclin 1蛋白表达上调,Bcl-2蛋白表达下调,NDS评分升高(P＜0.05);与I/R组比较,Sevo组、3-MA组和3-MA+ Sevo组脊髓LC3B、Beclin 1蛋白表达下调,Bcl-2蛋白表达上调,NDS评分降低(P＜0.05);Sevo组、3-MA组和3-MA+ Sevo组各指标比较差异无统计学意义(P＞0.05).结论 七氟醚预处理可减轻大鼠脊髓缺血再灌注损伤,其机制可能与上调Bcl-2,抑制自噬溶酶体途径,减轻自噬有关.