阻塞性黄疸伴肝功能不全患者顺式阿曲库铵的肌松效应

目的 观察单次静脉注射顺式阿曲席铵在阻塞性黄疸伴有肝功能不全患者的肌松效应.方法 30例择期行上腹部手术的患者均分为阻塞性黄疸伴有肝功能不全(Child-Pugh B级)组(G组)和肝功能正常组(C组).麻醉诱导均采用丙泊酚3 μg/ml、雷米芬太尼3～6 ng/ml、顺式阿曲库铵0.15 mg/kg后气管插管,评估插管条件,记录顺式阿曲库铵的肌松作用指标.结果 G组肌松起效时间较C组明显延长(P＜0.01);两组最大阻滞程度、插管条件、最大效应持续时间、单个颤搐刺激反应强度(T1)10%恢复时间、T125%恢复时间、T175%恢复时间、TOF比(T4/T1)70%恢复时间、恢复指数差异均无统计学意义.结论 阻塞性黄疸伴有肝功能小全患者单次静注顺式阿曲库铵后肌松起效时间明显长于肝功能正常者.     

老年患者顺式阿曲库铵不同用药方式的作用时效比较

目的观察顺式阿曲库铵两种不同用药方式在老年患者腹部手术中的肌松效应及对恢复速度的影响。方法 32例ASAⅡ～Ⅲ级择期老年腹部手术患者,随机分为两组（Ⅰ组和Ⅱ组,每组16例）。麻醉诱导均采用咪唑安定、异丙酚及芬太尼,以瑞芬太尼和异丙酚维持麻醉。Ⅰ组术中每当T1恢复到10%时单次静脉推注0.05～0.1mg/kg顺式阿曲库铵,Ⅱ组当T1恢复到5%时开始微量泵输注顺式阿曲库铵（2～3μg/（kg.min））,两组维持肌松T1〈10%,直到手术关腹后停止给药。术中记录肌松作用时间、最后注药或停药距T1为25%时间、恢复指数,并计算单位时间用药量。结果两组肌松效应和恢复指数相比均无统计学差异（P〉0.05）,单位时间用药量亦无统计学差异（P〉0.05）;最后注药或停药距T1为25%时间,Ⅰ组长于Ⅱ组（P〈0.05）。结论顺式阿曲库铵用于老年患者麻醉可产生良好的肌松效应,术中持续微量泵注射顺式阿曲库铵较为合理。     

不同剂量顺式阿曲库铵对患者拇内收肌与眼轮匝肌肌松效应的比较

目的 比较不同剂量顺式阿曲库铵对患者拇内收肌与眼轮匝肌的肌松效应.方法 全麻患者25例,ASA Ⅰ或Ⅱ级,年龄42～64岁,体重51～81 kg,随机分为2组,顺式阿曲库铵0.075ms/ks组(Ⅰ组,n=11)和顺式阿曲库铵0.15 mg/kg组(Ⅱ组,n=14).静脉注射咪达唑仑0.035～0.045mg/kg、异丙酚1.5～2 mg/kg、芬太尼0.1～0.2 mg、顺式阿曲库铵0.075 mg/kg或0.15 mg/kg行麻醉诱导,吸入50%氧化亚氮、间断静脉注射芬太尼维持麻醉.采用2台TOF-Watch SX加速度肌松监测仪同步监测眼轮匝肌和拇内收肌的神经肌肉阻滞情况,记录肌松起效时间、无反应期及T25%和T75%恢复时间.于眼轮匝肌肌颤搐抑制75%～80%时行气管插管,并评价气管插管条件.结果 2组气管插管条件良好且差异无统计学意义(P>0.05);与Ⅰ组比较,Ⅱ组拇内收肌和眼轮匝肌肌松起效时间缩短,T25%恢复时间、T75%恢复时间和无反应期延长(P<0.01);与拇内收肌比较,Ⅰ组眼轮匝肌T75%恢复时间缩短,Ⅱ组眼轮匝肌无反应期和T25%恢复时间缩短(P<0.05或0.01).结论 顺式阿曲库铵对拇内收肌和眼轮匝肌的肌松效应呈剂量依赖性,眼轮匝肌对顺式阿曲库铵的敏感性低于拇内收肌;监测顺式阿曲库铵对眼轮匝肌神经肌肉阻滞情况可有效指导气管插管.     

小儿不同剂量顺式阿曲库铵的肌松作用

目的通过观察小儿不同剂量顺式阿曲库铵的肌松作用,评价是否存在封顶效应,探讨小儿合适的麻醉诱导剂量。方法45例择期手术的息儿,年龄15～50月,ASAⅠ或Ⅱ级,随机分为3组(n=15):顺式阿曲库铵0.1 mg/kg组(A组)、顺式阿曲库铵0.15 mg/kg组(B组)、顺式阿曲库铵0.2 mg/kg(C组)。采用TOF-Guard肌松监测仪对尺神经行连续四个成串(TOF)刺激,监测拇内收肌肌颤搐变化;静脉注射异丙酚2 mg/kg、芬太尼2μg/kg及相应剂量顺式阿曲库铵麻醉诱导,吸入O2-N2O和静脉持续输注异丙酚维持麻醉;评价气臂插管条件评估分级,监测诱导期间血液动力学变化,记录起效时间(肌松药注毕至T1达最大抑制的时间)、临床肌松维持时间(肌松药注毕至T1恢复5%的时间)、临床肌松有效作用时间(T1从最大抑制至恢复25%的时间)、恢复指数(T1恢复从25%至75%的时间)、体内肌松作用时间(肌松药注毕至T1恢复95%的时间)。结果3组气管插管条件评估分级比较差异无统计学意义;三组T1达最大抑制时心率、平均动脉压组间和组内比较差异均无统计学意义。与A组相比,B组、C组起效时间较短,临床肌松维持时间、临床肌松有效作用时间、体内肌松作用时间较长(P<0.01);三组恢复指数差异无统计学意义。与B组相比,C组起效时间差异无统计学意义,但临床肌松维持时间、临床肌松有效作用时间、体内肌松作用时间较长(P<0.05或0.01)。结论小儿芬太尼复合异丙酚时,顺式阿曲库铵0.15 mg/kg(3倍ED95)是麻醉诱导的适宜剂量。     

麻黄碱预处理对顺式阿曲库铵肌松时效的影响

目的 观察麻黄碱预处理对顺式阿曲库铵肌松时效的影响.方法 选择50例ASAⅠ或Ⅱ级择期手术患者,随机均分为两组:观察组麻黄碱70 μg/kg静注后4 min内给予顺式阿曲库铵;对照组静注相同剂量的生理盐水后给予顺式阿曲库铵.比较两绀的肌松起效时间、肌松恢复时间和插管期间的血流动力学变化.记录入室后安静≥10 min诱导前(T0基础值)、插管即刻(T1)、插管后1 min(T2)和插管后3 min(T3)的MAP和HR.结果 与对照组比较,观察组肌松起效时间显著缩短(P<0.01);95%恢复时间显著缩短(P<0.05).与T0时比较,T2时观察组MAP明显升高,HR明显增快(P<0.05);T1、T2时对照组MAP明显降低,HR明显减慢(P<0.05或P<0.01).结论 静注麻黄碱70 μg/kg预处理后≤4 min时.再给予顺式阿曲库铵可有效缩短肌松起效时间和95%恢复时间.     

顺式阿曲库铵的组胺释放作用及其对血液动力学的影响

目的 在全麻诱导期间观察单次静注不同剂量（0．1－0．4mg/kg,2-8倍ED95）顺式阿曲库铵（Cis)后的组胺释放作用及其对血液动力学的影响,同时观察其肌松效应和插管条件,并与阿曲库铵（Atc)进行对照。方法 ASAⅠ-Ⅱ级全麻择期手术患者32例,随机分为CisⅠ组,CisⅡ组,CisⅢ组和Atc组。四组分别单次静注Cis 0.1mg/kg,0.2mg/kg,0.4mg/kg和Atc 0.5mg/kg。麻醉诱导用咪唑安定、依托咪酯及芬太尼。用Biometer加速度仪进行肌松监测。采用荧光分光光度法分别测定静注肌松药前及后2min,5min的血浆组胺浓度。同时记录注药前及后1－5min的收缩压u舒张压u平均动脉压和心率。结果 4组注药后2min和5min血浆组胺浓度与注药前相比均无统计学差异（P＞0．05）,4组注药前后的血液动力学变化均无显著性差异（P＞0．05）。静注0．2mg/kg和0．4mg/kg顺式阿曲库铵的起效时间明显快于静注0．1mg/kg顺式阿曲库铵和0．5mg/kg阿曲库胺（P＜0．05）。4组的插管条件及最大阻滞程度无显著性差异,对血流动力学亦无明显影响,随着剂量增大,起效时间明显缩短。顺式阿曲库铵用于麻醉诱导可产生良好的肌松效应,且无毒副作用。     

七氟醚麻醉诱导对顺式阿曲库铵起效时间的影响

目的 探讨七氟醚肺活量法吸入诱导和丙泊酚静脉诱导对顺式阿曲库铵起效时间的影响.方法 择期行胸外科或普外科手术的全麻患者60例,ASA Ⅰ或Ⅱ级,年龄18～65岁,随机均分为七氟醚组(S组)和丙泊酚组(P组).麻醉诱导:P组静脉注射咪达唑仑0.05 mg/kg、芬太尼2μg/kg、丙泊酚1 mg/kg;S组采用肺活量吸入法,七氟醚吸入浓度8%.两组患者意识消失后均给予顺式阿曲库铵0.15 mg/kg.监测肌松药起效时间,意识消失时间,血流动力学指标,并评价气管插管条件.结果 患者意识消失时间、顺式阿曲库铵起效时间S组明显短于P组(P<0.05或P<0.01).插管引起的心血管反应S组小于P组(P<0.05).结论 七氟醚吸入诱导能明显缩短顺式阿曲库铵的起效时间,且循环功能稳定.     

罗库溴铵和阿曲库铵联合应用的肌松效应分析

目的探讨罗库溴铵和阿曲库铵联合应用时的肌松效应。方法择期全麻手术女性成年患者147例,丙泊酚和舒芬太尼静脉诱导,输注丙泊酚维持麻醉。面罩辅助或控制呼吸,用加速度仪以连续4次刺激(TOF)方式透皮刺激腕部尺神经,获取肌松药作用起效时间和T1最大抑制程度(Tmax)。按观测项目将患者均分成四组。结果阿曲溴铵ED95为(220.8±3.6)μg/kg,罗库溴铵ED95为(286.3±3.1)μg/kg。0.5×ED95的罗库溴铵与阿曲库铵联合使用,肌松效应达到T1抑制93%~97%时,阿曲库铵的剂量为63.6μg/kg。罗库溴铵0.5×ED95与阿曲库铵63.6μg/kg联合使用,Tmax为(95.3±0.9)%,变异系数1.0%。Ⅳ组中三个亚组的Tmax基本相同,合用组作用起效时间比阿曲库铵组快(P<0.01)。给予肌松药前和注药后5min内,MAP和HR的波动幅度均小于5%。结论罗库溴铵与阿曲库铵合用呈协同作用。当罗库溴铵剂量为0.5×ED95时,为获得T1抑制95%的肌松效应,阿曲库铵的合理用量为63.6μg/kg,比阿曲库铵的ED95减少71.2%。     

国人顺式阿曲库铵的剂量反应测定

目的　采用经典的单次注射法建立顺式阿曲库铵的剂量 -反应曲线 ,了解该肌松药应用于国人的量效关系 ,并确定其 ED50 、ED75、ED90 和 ED95值 ,为临床研究和应用提供参考。方法　 ASA ～ 级择期手术患者 2 4例 ,随机分为 4组。咪唑安定、依托咪酯、芬太尼麻醉。 4组病人分别单次静注顺式阿曲库铵 0 .0 2、0 .0 3、0 .0 4和 0 .0 5 m g/ kg,观察拇指内收肌四个成串刺激 ( TOF)第一次反应 ( T1 )最大抑制的百分率并进行概率单位转换。将顺式阿曲库铵的首次剂量进行对数转换 ,用直线回归方法建立顺式阿曲库铵的剂量 -反应曲线 ,同时记录起效时间。结果　顺式阿曲库铵的 ED50 、ED75、ED90和 ED95的值分别为 :0 .0 3、0 .0 3 9、0 .0 4 9和 0 .0 5 6mg/ kg。顺式阿曲库铵起效时间在四个剂量组之间无显著差异 ( P>0 .0 5 )。结论　国外文献报道顺式阿曲库铵的 ED95值为 0 .0 4 7～ 0 .0 5 3 mg/ kg。本文得到的 ED95值为 0 .0 5 6m g/ kg,与国外文献的报道相拟     

急性高容量血液稀释对全麻患者顺式阿曲库铵药效学的影响

目的 探讨急性高容量血液稀释(AHH)对全麻患者顺式阿曲库铵药效学的影响.方法 择期腹部手术患者印例,年龄18～60岁,ASAI或Ⅱ级,随机分为对照组(C组)和AHH组,每组30例,各组按顺式阿曲库铵首剂量(首剂量分别为30、40、50μg/kg,总用量100 μg/kg)分为3个亚组,每亚组10例.采用TOF-Wateh~(R)SX肌松监测仪监测神经肌肉阻滞情况.AHH组经30～40 min静脉输注6%羟乙基淀粉130/0.4 15 ml/kg行血液稀释,AHH后各亚组分别给予首剂量顺式阿曲库铵,当T_1达最大抑制后再注入余量.记录肌松起效时间、临床肌松作用时间、体内作用时间及恢复指数.采用概率单位法计算T_1抑制50%、90%、95%时顺式阿曲库铵的用量(ED_(50)、ED_(90)、ED_(95).结果 与C组比较,AHH组顺式阿曲库铵ED_(50)、ED_(90)、ED_(95)升高,肌松起效时间延长,临床肌松作用时间及体内作用时间缩短(P<0.05或0.01),恢复指数差异无统计学意义(P>0.05).结论 AHH可降低顺式阿曲库铵的肌松效应.     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

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.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.