破裂型椎间盘突出动物模型中自身免疫反应的实验研究

目的:从动物实验的角度探讨破裂型椎间盘突出动物模型中的自身免疫反应.方法:20只SD大鼠分为两组,实验组采用自体髓核移植于坐骨神经旁的方法建立破裂型椎间盘突出动物模型(坐骨神经痛模型);对照组大鼠手术方法同实验组,但不放置髓核.术前及术后1、2、3周时采用爬坡实验及后肢机械缩爪阈值测定评估大鼠造模前后后肢运动能力及痛觉过敏的变化.术后3周时处死动物应用透射比浊法检测大鼠血清中免疫球蛋白IgG、IgM的含量,ELISA法测定血清中TNF-α、IL-6、IL-12的含量;采用免疫组化染色观察移植髓核中抗原抗体复合物沉积情况;应用BCA蛋白定量法观察坐骨神经中磷脂酶A2(PLA2)的活性.结果:所有大鼠模型建立前爬坡试验结果均为Ⅳ级,造模后对照组爬坡试验仍为Ⅳ级,实验组在造模后1、2及3周时爬坡试验均为Ⅲ级.实验组大鼠造模后1、2、3周时的后肢机械缩爪阈值分别为67.2±8.4、41.3±5.2及40.7±5.3mmHg,较术前(90.4±5.0mmHg)及对照组明显降低(P＜0.01),出现较为明显的痛觉过敏.术后3周实验组大鼠血清中IgG含量4.98±0.96g/L及IgM含量1.45±0.37g/L较对照组(4.31±0.77g/L及0.79±0.35g/L)明显上升(P＜0.05);血清中TNF-α、IL-6、IL-12的含量(205.77±46.32pg/L,186.4±87.3pg/L,69.23±27.46pg/L)较对照组(11.01±2.53pg/L,85.0± 13.2pg/L,21.65±11.93pg/L)均明显升高(P＜0.05).实验组大鼠移植髓核中出现抗原抗体复合物阳性沉积,阳性率为80％,明显高于对照组(P＜0.01);其坐骨神经中PLA2活性为0.0766±0.0039μmoL/(min·L),较对照组0.0006±0.0010μmoL/(min·L)明显升高(P＜0.05).结论:破裂型椎间盘突出动物模型中存在着由移植髓核引起的全身及局部异常的自身免疫反应,这可能是导致其疼痛的主要原因.     

椎体成形术对兔手术椎体相邻椎间盘的影响

[目的]探讨椎体成形术(vertebroplasty,VP)是否会引起兔手术椎体相邻椎间盘的退变,以及椎间盘的退变程度与聚甲基丙烯酸甲酯(polymethyl methacrylate,PMMA)用量的相关性.[方法]80只5个月龄雌性新西兰大白兔,随机选16只为正常对照组(A组),剩余的64只采用去势法建立兔骨质疏松模型后随机分为4组,设L5为手术椎体.B组(实验对照组)L5不注入任何药物;C组L5注入PMMA0.1 ml;D组L5注入PMMA0.3 ml;E组L5注入PMMA 0.5ml.每组分别于术前及术后1、3、6个月各处死4只动物,进行X线、MRI检查,通过计算椎间盘高度指数百分数(disc height Index percentage,DHIP)和MRI指数,来定量分析椎间盘退变程度.并取相邻椎间盘送病理,采用Masuda评分评估椎间盘退变程度.[结果]A、B组椎间盘的DHIP、MRI指数和Masuda评分在各个时间点均无明显变化.C、D、E组在术前及术后1个月时的DHIP、MRI指数和Masuda评分较A、B组无明显改变.第3个月时,E组椎间盘的DHIP、MRI指数较其他各组均有降低,且MRI指数和Masuda评分较A、B组有统计学差异(P＜0.05).第6个月时,D、E组椎间盘的DHIP、MRI指数和Masuda评分跟术前及术后1、3个月比较均有显著统计学差异(P＜0.05),E组的DHIP和MRI指数均明显低于A、B、C、D组.组织学退变也较A、B、C、D明显,Ma-suda评分明显高于A、B、C、D组.[结论]VP可以引起手术椎体相邻椎间盘的退变,并且椎间盘退变程度与PM-MA用量相关.     

基于Notch通道右归丸对大鼠退变椎间盘的影响

[目的]探讨右归丸对大鼠退变腰椎间盘结构的潜在干预机制。[方法]将30只雄性SD大鼠随机分为3组,每组10只。正常对照组为健康大鼠,不做特殊处理;退变组采用纤维环穿刺法建立大鼠椎间盘退变模型。药物组在退变组基础上予右归丸灌胃2周。ELISA检测血清炎症因子IL-10、MIF、TNF-α水平;Western blot检测椎间盘组织中Ⅱ型胶原、Notch1蛋白表达水平。[结果]与正常对照组比较,退变组和药物组的大鼠血清白细胞介素-10(interleukin-10, IL-10)[(22.3±2.8) pg/ml vs(30.9±1.7) pg/ml vs (53.2±7.5) pg/ml, P<0.001]、巨噬细胞移动抑制因子（macrophage migration inhibitory factor, MIF）[(0.3±0.0) pg/ml vs (1.3±0.3) pg/ml vs (0.6±0.2) pg/ml, P<0.001]、肿瘤坏死因子α (tumor necrosis factor-α, TNF-α)[(12.5±3.0) pg/ml vs (52.6±...     

不同剂量全氟化碳汽化吸入预处理治疗急性肺损伤兔的实验研究

目的 探讨不同剂量全氟化碳(perfluorocarbon,PFC)汽化吸入预处理对油酸型急性肺损伤(acute lung injury,ALI)实验兔早期炎性因子的影响,并得到其中最低有效预处理剂量. 方法 将24只实验兔采用随机数字表法,分为4组(每组6只),对照组(C组)、PFC 1 ml·kg-1·h-1预处理组(PFC-1组)、PFC 2ml·kg-1·h-1预处理组(PFC-2组)、PFC 3 ml· kg-1·h-1预处理组(PFC-3组).动物麻醉后气管插管行机械通气,C组机械通气60 min后建立油酸型ALI模型,3组预处理组分别汽化吸入1 ml·kg-1·h-1、2ml·kg-1·h4和3ml·kg1·h-1速率的PFC 60 min,再建立油酸型ALI模型,4组在ALI后继续行机械通气120 min.4组分别于麻醉通气30 min(T1,基础值)、PFC预处理60 min时(T2,C组为机械通气60 min)、ALI造模成功时(T3)、ALI后120 min(T4)等时点检测氧合指数(PaO2/FiO2).实验结束后留静脉血离心取血清,对左肺进行肺灌洗留取肺泡灌洗液(bronchoalveolar lavage fluid,BALF),通过ELISA法检测血清及BALF中肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)和白介素-1β (interleckin-1β,IL-1β)的含量. 结果 与C组(477±5、472±5、103±5、69±4)比较,3组PFC预处理组[PFC-1(474±11、478±4、122±12、83±5)、PFC-2组(472±10、478±4、140±11、88±3)、PFC-3组(479±9、480±6、146±15、86±2)]在各时点PaO2/FiO2均明显升高(P＜0.05),其中PFC-2组、PFC-3组PaO2/FiO2均高于同时点的PFC-1组(P＜0.05).与C组(229±5) ng/L比较,PFC-1组(220±5) ng/L、PFC-2组(209±3) ng/L和PFC-3组(212±3) ng/L组血清中TNF-α的含量明显降低(P＜0.05),其中PFC-2组、PFC-3组较PFC-1组显著降低(P＜0.05);PFC-2组(323±9) ng/L、PFC-3组(344±12) ng/L BALF中TNF-α的含量均较C组(365±14) ng/L和PFC-1组(367±13) ng/L明显降低(P＜0.05),其中PFC-2组比PFC-3组明显降低(P＜0.05).血清[C组(102±3) ng/L、PFC-1组(100±3)ng/L、PFC-2组(77±1) ng/L、PFC-3组(84±2) ng/L]和BALF[C组(116±2) ng/L、PFC-1组(116±3) ng/L、PFC-2组(93±2) ng/L、PFC-3组(96±4) ng/L]中IL-1β的含量,PFC-2、PFC-3组均较C组和PFC-1组明显降低(P＜0.05),其中血清中PFC-2组比PFC-3组明显降低(P＜0.05). 结论 经气道2 ml·kg-1·h-1和3 ml· kg-1·h-1的PFC吸入两种速率的预处理后,都能改善ALI兔的氧合功能,减少早期炎性因子TNF-α和IL-1β的释放,考虑2ml· kg-1·h-1为3组PFC吸入预处理中最低有效剂量.     

右美托咪定复合左布比卡因用于剖宫产术后硬膜外镇痛的临床研究

目的 探索右美托咪定(dexmedetomidine,Dex)联合低浓度左布比卡因在剖宫产术后硬膜外自控镇痛治疗中的应用可行性及对舒芬太尼消耗量的影响. 方法 90例足月孕单胎择期行剖宫产术的孕妇,ASA分级Ⅰ、Ⅱ级,按随机数字表法分为3组(每组30例):对照组(C组),舒芬太尼1.5 μg/kg+0.1％左布比卡因;Dex 1组(D1组),舒芬太尼1.5μg/kg+0.1％左布比卡因+Dex 0.02 μg·kg-1·h-1;Dex 2组(D2组),舒芬太尼1.5 μ.g/kg+0.1％左布比卡因+Dex 0.05 μg·kg1·h-1,各组药物均用生理盐水稀释至150 ml.孕妇均采用L～L4硬膜外腔联合蛛网膜下腔阻滞麻醉,术毕均快速泵注镇痛液2ml,背景输注速度为2ml/h,患者自控镇痛(patient controlled analgesia,PCA)锁定时间15 min,每次2 ml.记录术前产妇的一般资料,手术与麻醉时间,副作用(皮肤瘙痒、恶心、呕吐)的发生率,舒适度(Bruggrmann comfort scale,BCS)评分以及术后4、8、12、24、48 h的VAS评分和Ramsay评分,统计PCA键有效按压次数和48 h舒芬太尼用量. 结果 术后4、8、12、24、48 h,C组Ramsay评分[(2.0±0.5)、(1.7±0.5)、(1.6±0.6)、(1.6±0.5)、(1.8±0.4)分]明显低于D1组[(2.3±0.5)、(2.3±0.6)、(2.1±0.5)、(2.3±0.5)、(2.2±0.5)分]和D2组[(2.3±0.5)、(2.4±0.5)、(2.3±0.5)、(2.4±0.5)、(2.3±0.5)分](P＜0.05或P＜0.01);D1组[(0.5±0.6)、(0.8±0.9)、(0.9±0.9)、(1.0±0.9)、(1.1±0.8)分]和D2组[(0.4±0.6)、(0.5±0.7)、(0.7±0.7)、(0.8±0.8)、(0.9±0.7)分]VAS评分明显低于C组[(1.3±1.0)、(1.5±1.1)、(1.8±1.0)、(1.9±0.7)、(1.9±0.7)分](P＜0.05或P＜0.01).D2组皮肤瘙痒发生率(3.33％)明显低于C组(26.67％)(P＜0.05).D2组BCS评分[(3.1±0.7)分]显著高于C组[(3.1±0.7)分]与D1组[(1.9±0.7)分](P＜0.05或P＜0.01).C组48 h舒芬太尼消耗量[(1.041±0.025) μg/kg]明显大于D1组[(1.020±0.021)μ.g/kg]和D2组[(1.003±0.019) μg/kg](P＜0.01),且D1组比D2组消耗量大(P＜0.05). 结论 小剂量Dex能明显提高左布比卡因和舒芬太尼剖宫产术后的镇痛效果和安全性,具有良好的应用前景.     

小剂量氯胺酮预处理对大鼠肠缺血/再灌注后肝脏血红素加氧酶-1表达的影响

目的 观察小剂量氯胺酮对血红素加氧酶-1 (heme-oxygenase 1,HO-1)在大鼠肠缺血/再灌注(ischemia/reperfusion,I/R)后肝脏中表达的影响,并对其可能的保护机制作一初步探讨. 方法 48只雄性成年SD大鼠按随机数字表法分为A组(氯胺酮10 mg/kg术前30 min腹腔注射+假手术)、B组(盐水0.2 ml术前30 min腹腔注射+假手术)、C组(氯胺酮10 mg/kg术前30 min腹腔注射+小肠I/R)、D组(盐水0.2 ml术前30 min腹腔注射+小肠I/R)、E组(锌原卟啉5 mg/kg、氯胺酮10 mg/kg术前30 min腹腔注射+小肠I/R)、F组(锌原卟啉5 mg/kg、盐水0.2 ml术前30 min腹腔注射+小肠I/R),每组8只.小肠I/R造模组大鼠通过夹闭肠系膜上动脉60 min,然后松血管夹,于再灌注6h后取材,测定肝组织丙二醛(malondialdehyde,MDA)含量、超氧化物歧化酶(superoxide dismutase,SOD)活性;采用免疫组化法测定肝组织HO-1的表达和定量;光镜下观察肝脏病理学改变;取外周静脉血测血清谷丙转氨酶(glutamic-pyruvic transaminase,GPT)、谷草转氨酶(glutamic-oxaloacetic transaminase,GOT). 结果 A、B两组间各项数据比较差异无统计学意义(P＞0.05);各缺血造模组大鼠肝组织MDA含量:C组[(2.69±0.35) μmol/g]、D组[(4.62±0.36) μmol/g]、E组[(4.35±0.24) μmol/g]、F组[(4.74±0.34) μmol/g]与B组[(1.08±0.26) μmol/g]比较,显著升高;SOD活力:C组[(129±6) μU/L]、D组[(102±5) μU/L]、E组[(99±4)μU/L]、F组[(96±6)μU/L]与B组[(133±7) μU/L]比较,显著下降;血清GOT、GPT含量:C组[GPT(212±21) U/L,GOT(129±16) U/L]、D组[GPT(416±33) U/L,GOT(362±15)U/L]、E组[GPT(407±29) U/L,GOT(359±14) U/L]、F组[GPT(414-±40) U/L,GOT(366±16) U/L]与B组[(GPT(53±9) U/L,GOT(83±7) U/L]比较,显著升高;HO-1表达:C组(0.472±0.126)、D组(0.324±0.078)、E组(0.337±0.092)、F组(0.328±0.083) OD与B组(0.078±0.010) OD比较,显著上调(P＜0.05或P＜0.01);与D组比较,C组血清GPT、GOT、肝组织MDA含量均显著降低,SOD活力显著上升,HO-1表达上调(P＜0.05);与D组比较,E组、F组血清GPT、GOT及MDA、SOD值差异无统计学意义(D0.05);E组和C组比较,血清GPT、GOT,肝组织MDA含量显著升高,SOD活力显著下降,HO-1表达下调(P＜0.05). 结论 小剂量氯胺酮预处理能减轻肠I/R后造成的肝脏损伤,这种作用在一定程度上是通过上调HO-1的表达来实现的.     

不同剂量右美托咪定对髋关节置换术老年高血压患者术后谵妄的影响

目的 评价不同剂量右美托咪定(dexmedetomidine,Dex)对全身麻醉下老年高血压患者术后谵妄(postoperative delirium,POD)的影响. 方法 选择择期行髋关节置换术老年高血压患者120例,年龄65～85岁,采用随机数字表法分为高剂量Dex组(D1组)、低剂量Dex组(D2组)和对照组(C组),每组40例.麻醉诱导前D1组、D2组分别泵注Dex 0.6、0.2 μg/kg负荷量,10 min泵完,分别继续以0.4、0.2 μg·kg-1·h-1维持至手术结束前30 min;C组泵注等量生理盐水.观察时间点为给药前(T0)、给药后10 min(T1)、气管插管时(T2)、气管导管拔除时(T3)、术后6 h(T4)、术后24 h(T5)、术后48 h(T6).记录T0、T1、T2、T3各时点的MAP和HR情况,于T0、T3、T4、T5及T6时点采集静脉血检测血糖(blood glucose,Glu)、皮质醇(cortisol,Cor)和IL-6的血浆浓度,采用谵妄分级量表-98修订版(DRS)评估T4～T6时患者POD的发生情况. 结果 T2、T3时C组MAP [(135±12)、(127±12) mmHg(1 mmHg=0.133 kPa)]、HR[(105±11)、(94±9)次/min]比T0时[(111±11)mmHg、(71±10)次/min]显著升高(P＜0.05),T3～T5时C组Glu[(9.8±0.7)、(9.6±0.4)、(10.6±0.6) mmol/L],Cor[(550±55)、(466±59)、(450±44) nmol/L]、IL-6[(175±14)、(115±10)、(81±8) μg/L]比T0时Glu[(4.2±0.4) mmol/L],Cor[(353±37)nrnol/L],IL-6[(58±6)μg/L]显著升高(P＜0.05);T1～T3时D1组MAP[(90±10)、(86±10)、(90±9) mmHg],HR [(62±8)、(63±11)、(66±9)次/min]比C组MAP [(121±10)、(135±12)、(127±12) mmHg]、HR[(79±12)、(105±11)、(94±9)次/min]明显降低(P＜0.05),T3～T5时D1组Cor[(421 ±39)、(345±35)、(325±35) nmol/L]、IL-6[(82±11)、(106±10)、(67±11) μg/L]比D2组Cor[(466±43)、(399±36)、(369±42) nmol/L],IL-6[(104±12)、(136±14)、(93±11)μg/L]明显降低(P＜0.05).与C组比较,D1组、D2组POD的发生率明显降低(P＜0.05),与D2组比较,D1组POD发生率明显降低(P＜0.05). 结论 持续泵注不同剂量Dex均能维持血流动力学稳定,减少POD的发生;高剂量Dex对POD的防治更有效;其机制可能与其减轻应激反应及抑制炎症反应水平有关.     

右美托咪定对食管癌根治术单肺通气患者肿瘤坏死因子-α和白细胞介素-6的影响

目的 观察右美托咪定对食管癌根治术单肺通气患者血浆肿瘤坏死因子(TNF)-α和白细胞介素(IL)-6水平的影响.方法 60例拟行食管癌根治术的患者,随机分为D1组、D2组和C组,每组20例.D1组麻醉诱导前0.6μg/kg静脉泵注右美托咪定;D2组麻醉诱导后以0.3μg/(kg·h)静脉泵注右美托咪定;C组为对照组.分别测定麻醉诱导前20 min(T0),气管插管后10 min(T1),单肺通气30 min(T2),单肺通气90 min(T3)及再次双肺通气后10 min(T4)5个时间点血浆中TNF-α和IL-6浓度.结果 3组患者血浆TNF-α水平在T3、T4时点较T0高(P ＜0.05);D1组和D2组在T3(10.5±2.5,11.1 ±2.6)、T4(11.2±2.4,11.8±2.7)时点较C组增高(P＜0.05).3组患者血浆IL-6水平在T4时点较T0高(P ＜0.05);D1组和D2组在T4时点(23.2±3.3,23.9±3.2)较C组增高(P＜0.05).结论 术前静脉泵注0.6 μg/kg及术中持续以0.3μg,/(kg·h)静脉泵注右美托咪定均能抑制食管癌根治术单肺通气患者血浆中TNF-α和IL-6水平升高.     

参附注射液对大鼠机械通气相关性肺损伤的保护作用及其机制

目的 探讨参附注射液(Shenfu injection,SF)对大鼠机械通气(mechanical ventilation,MV)相关性肺损伤的保护作用及其机制. 方法 40只健康成年雄性Wister大鼠采用随机数字表法分为4组,每组10只:对照组(C组)、正常潮气量MV组(N组)、大潮气量MV组(L组)、大潮气量MV+SF处理组(SF组).C组保留自主呼吸;N组、L组和SF组MV4h,潮气量分别设置为8～10 ml/kg、40 ml/kg、40 ml/kg,SF组于MV前15 min静脉注射SF 10 ml/kg.实验结束处死动物,收集支气管肺泡灌洗液(bronchoalveolar lavage fluid,BALF),测定BALF中总蛋白、IL-1β、IL-18和TNF-α的浓度;取肺组织,测量湿/干重比(wet/dry,W/D),采用免疫组化法检测肺组织NF-κB的表达,观察病理学改变并进行肺损伤评分. 结果 SF组BALF中TNF-α、IL-1β、IL-18浓度分别为(65±11)、(47±9)、(58±8) ng/L,较L组(99±7)、(69±7)、(86±7) ng/L明显降低(P＜0.05);SF组大鼠肺损伤评分、W/D、肺组织NF-κB光密度值分别为(8.5±1.8)分、(5.0±1.6)、(0.32±0.28),较L组(14.1±2.7)分、(5.5±1.8)、(0.54±0.33)均明显降低(P＜0.05). 结论 SF可减轻大鼠MV相关性肺损伤,其机制可能与SF抑制肺内NF-κB通路的活性且降低肺内炎性因子的释放有关.     

复方玄驹胶囊治疗自身免疫性前列腺炎大鼠的实验研究

目的:研究复方玄驹胶囊对自身免疫性前列腺炎大鼠的治疗效果。方法:健康Wistar大鼠60只,随机分为5组,对照组、低浓度蛋白免疫模型组、低浓度蛋白免疫+复方玄驹胶囊全方治疗组、高浓度蛋白免疫模型组、高浓度蛋白免疫+复方玄驹胶囊全方治疗组。除对照组外,其余4组用高低两种浓度(15 mg/ml及80 mg/ml)的同种大鼠前列腺匀浆蛋白提纯液进行注射造模。造模(30 d)成功后,对照组和模型组生理盐水[1 ml/(200 g·d)]灌胃,治疗组用生理盐水溶解的复方玄驹胶囊全方[0.068 g/(ml·d)]灌胃,随后分别于30、45、60 d分批处死大鼠。用ELISA法检测大鼠血清中的IL-8、IL-10及TNF-α的表达,并观察大鼠前列腺组织病理切片。结果:与模型组相比,经复方玄驹胶囊全方灌胃治疗的高浓度蛋白免疫大鼠血清中IL-8、TNF-α在造模45 d时由(148.54±17.23)pg/ml、(62.14±5.59)pg/ml下降到(100.77±11.08)pg/ml、(32.63±2.91)pg/ml(P0.05);60 d时由(143.69±17.28)pg/ml、(59.38±5.50)pg/ml降到(95.77±10.53)pg/ml、(29.63±2.66)pg/ml(P0.05)。低浓度组造模45 d时IL-8、TNF-α亦由(128.47±12.21)pg/ml、(40.43±3.64)pg/ml下降至(111.76±10.07)pg/ml、(35.44±3.17)pg/ml(P0.05),60 d时由(131.07±10.93)pg/ml、(43.34±3.91)pg/ml降至(97.46±8.75)pg/ml、(30.44±2.75)pg/ml(P0.05)。高浓度蛋白免疫的治疗组大鼠血清IL-10在造模45 d、60 d分别由(189.14±16.78)pg/ml、(184.14±15.89)pg/ml上升至(230.48±29.96)pg/ml、(248.48±31.03)pg/ml(P0.05),低浓度组由(223.14±17.87)pg/ml、(224.14±17.93)pg/ml升高至(231.42±23.18)pg/ml、(249.42±24.97)pg/ml(P0.05)。病理切片示对照组无明显变化;实验组病理切片显示大鼠前列腺组织腺体结构破坏,炎性细胞浸润;治疗组治疗15 d后光镜下观察病变逐步改善,腺腔增大,上皮细胞轻度增生,间质中无明显炎性细胞浸润,可见少量纤维组织。结论:复方玄驹胶囊能降低自身免疫性前列腺炎大鼠前列腺组织炎性改变,并有效改善炎性因子表达,对大鼠自身免疫性前列腺炎有一定疗效。     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.     

Intravenous endotoxin does not increase tissue extravasation of albumin in rats

Background : It is unclear whether activation of the inducible nitric oxide synthase (iNOS) increases or decreases the extravasation of plasma.
Methods : Chloralose anaesthetised male Wistar rats received E. coli lipopolysacharide (LPS), 3 mg kg^-1 i.v., or the corresponding volume of saline, 3 or 5 h before the end of the experiment. Mean arterial pressure (MAP) and heart rate (HR) were recorded. Tissue clearance of radio-labelled albumin, during the last 2 h of each experiment, was determined by a double-isotope method. In separate animals, the serum concentration of nitrite and nitrate was determined, 5 h after LPS or the solvent.
Main Results : LPS initially decreased MAP and lastingly increased HR. In the 3-h LPS animals (n=8), tissue plasma clearance was lower in the heart and calf muscle and increased only in diaphragm, compared to corresponding control animals (n=8). In the 5-h LPS rats, clearance was lowered (n=8) in the entire gastrointestinal tract and in testes, compared to controls (n=8). The serum nitrite/nitrate concentration was higher in animals given LPS (n=6) than in controls (n=6).
Conclusion : After LPS, tissue clearance of albumin was not increased in any major tissue, in spite of increased serum levels of NO end products. Apparently, after activation of iNOS, the augmented release of NO is not necessarily associated with increased albumin extravasation.     

Adrenaline markedly improves thoracic epidural analgesia produced by a low-dose infusion of bupivacaine, fentanyl and adrenaline after major surgery: A randomised, double-blind, cross-over study with and without adrenaline

Background: Basic pharmacological research indicates that there are synergistic antinociceptive effects at the spinal cord level between adrenaline, fentanyl and bupivacaine. Our clinical experience with such a mixture in a thoracic epidural infusion after major surgery confirms this. The objectives of the present study were to evaluate the effects on postoperative pain intensity, pain relief and side effects when removing adrenaline from this triple epidural mixture. Methods: A prospective, randomised, double-blind, cross-over study was carried out in 24 patients after major thoracic or abdominal surgery. Patients with only mild pain when coughing during a titrated thoracic epidural infusion of about 10 ml · h^?1 of bupivacaine 1 mg · ml^?1, fentanyl 2 μg · ml^?1, and adrenaline 2 μg · ml^?1 were included. On the 1^st and 2^nd postoperative days each patient was given a double-blind epidural infusion, at the same rate, with or without adrenaline. The effect was observed for 4 h or until pain when coughing became unacceptable in spite of a rescue analgesic procedure. Rescue analgesia consisted of up to two epidural bolus injections per hour and i.v. morphine if necessary. All patients received rectal paracetamol 1 g, every 8 h. Fentanyl serum concentrations were measured with a radioimmunoassay technique at the start and end of each study period. Main outcome measures were extent of sensory blockade and pain intensity at rest and when coughing, evaluated by a visual analogue scale, a verbal categorical rating scale, the Prince Henry Hospital pain score, and an overall quality of pain relief score. Results: The number of hypaesthetic dermatomal segments decreased (P <0.001) and pain intensity at rest and when coughing increased (P <0.001) when adrenaline was omitted from the triple epidural mixture. This change started within the first hour after removing adrenaline. After 3 h pain intensity when coughing had increased to unacceptable levels in spite of rescue analgesia (epidural bolus injections and i.v. morphine). Within 15–20 min after restarting the triple epidural mixture with adrenaline, pain intensity was again reduced to mild pain when coughing. Serum concentration of fentanyl doubled from 0.22 to 0.45 ng · ml^?1 (P <0.01), and there was more sedation during the period without adrenaline. Conclusions: Adrenaline increases sensory block and improves the pain-relieving effect of a mixture of bupivacaine and fentanyl infused epidurally at a thoracic level after major thoracic or abdominal surgery. Serum fentanyl concentrations doubled and sedation increased when adrenaline was removed from the epidural infusion, indicating more rapid vascular absorption and systemic effects of fentanyl.     

Reduction of Plasma Fibrinogen, Immunoglobulin G, and Immunoglobulin M Concentrations by Immunoadsorption Therapy with Tryptophan and Phenylalanine Adsorbents

Abstract Immunoadsorption (1A) therapy with tryptophan (TR-350) or phenylalanine (PH-350) adsorbents has been used to reduce the concentration of serum antibodies in human lymphocyte antigen (HLA)-immunized patients. Other forms of plasma purification have been reported to reduce the level of fibrinogen, which affects the blood properties. In this study we investigated the effects of IA therapy using both adsorbents on plasma fibrinogen and immunoglobulins G and M in 13 patients (8 patients were treated with TR-350, and 5 patients were treated with PH-350). During each session 1 plasma volume (2.8 ± 0.4 L of plasma) was processed through the immunocolumn and then returned to the patient together with the blood cells. Compared with the pretreatment values, the plasma fibrinogen, IgG, and IgM concentrations were significantly reduced after IA therapy (p < 0.01 for TR-350; p < 0.04 for PH-350). There was a positive correlation between the degree of reduction of plasma proteins and the number of IA treatments given. A nonpara-metric test (Wilcoxon's signed-rank test or the Mann-Whitney test) was used for statistical analysis. We conclude from our study that IA therapy effectively lowers the plasma levels of fibrinogen, IgG, and IgM and thus can be considered a valuable alternative to other blood purification methods.     

Utilisation des médicaments prokinétiques en réanimation : indications et limites ?

Enteral feeding is often limited by gastric and intestinal motility disturbances in critically ill patients, particularly in patients with shock. So, promotility agents are frequently used to improve tolerance to enteral nutrition. This review summaries the pathophysiology, presents the available pharmacological strategies, the clinical data, the counter-indications and the principal limits. The clinical data are poor. No study demonstrates a positive effect on clinical outcomes. Metoclopramide and erythromycin seems to be the more effective. Considering the risk of antibiotic resistance, the first line use of erythromycin should be avoided in favor of metoclopramide.     

Anesthésie générale chez l’enfant : quid des pratiques en 2010 ?

Introduction

The practice of pediatric anesthesia requires a regular update of scientific knowledge and technical skills. To provide the most adequate Continuing Medical Education programs, it is necessary to assess the practices of pediatric anesthesiologists. Thus, the objective of this survey was to draw a picture of the current clinical practices of general anesthesia in children, in France.

Material and methods

One thousand one hundred and fifty questionnaires were given to anesthesiologists involved in pediatric cases. These questionnaires collected information on various aspects of clinical practice relative to induction, maintenance, recovery from general anaesthesia and also classical debated points such as children with Upper Respiratory Infection (URI), emergence agitation, epileptoid signs or anaesthetic management of adenoidectomy. Differences in practices between CHG (general hospital), CHU (teaching hospital), LIBERAL (private) and PSPH (semi-private) hospitals were investigated.

Results

There were 1025 questionnaires completed. Fifty-five percent of responders worked in public hospitals (CHG and CHU); 77% had a practice that was 25% or less of pediatric cases. In children from 3 to 10 years: 72% of respondents used always premedication and two thirds performed inhalation induction in more than 50% of cases. For induction, 53% used sevoflurane (SEVO) at 7 or 8%. Respondents from LIBERAL used higher SEVO concentrations. Tracheal intubation was performed with SEVO alone (37%), SEVO and propofol (55%) and SEVO with myorelaxant (8%), 93% of respondents used a bolus of opioid. For maintenance, the majority of respondents used SEVO associated with sufentanil; desflurane and remifentanil were more frequently used in CHU. Two thirds of respondents used N₂O. Depth of anesthesia was commonly assessed by hemodynamic changes (52%), end tidal concentration of halogenated (38%) or automated devices based on EEG (7%). In children with URI, 98% of respondents used SEVO for anesthesia. To control the airway 42% used a tracheal tube, 30% a laryngeal mask and 20% a facial mask. Emergence agitation was an important concern for two thirds of respondents, while epileptoid signs were considered as important by only 20%. Eighty-nine percent of respondents practiced anesthesia for adenoidectomy. Anesthesia was induced by inhalation of SEVO 7–8% (41%), 6% (39%) or 4% (12%), 66% put an intravenous line (less frequently in LIBERAL). 67% of the responders managed adenoidectomy without any device to control the airway (more frequently in LIBERAL), 32% administrated a bolus of opioid (less frequently in LIBERAL).

Discussion

This survey demonstrated that the practices regarding general anesthesia in children are relatively homogenous. Most of the differences appeared between LIBERAL and the others structures; the anaesthetic management for adenoidectomy illustrates these findings.     

Intérêt d’une rééducation précoce pour les patients neurologiques

Rehabilitation improves the functional prognosis of patients after a neurologic lesion, and tendency is to begin rehabilitation as soon as possible. This review focuses on the interest and the feasibility of very early rehabilitation, initiated from critical care units. It is necessary to precisely assess patients’ impairments and disabilities in order to define rehabilitation objectives. Valid and simple tools must support this evaluation. Rehabilitation will be directed to preventing decubitus complications and active rehabilitation. The sooner rehabilitation is started; the better functional prognosis seems to be.