舒芬太尼在术后病人自控硬膜外镇痛的应用

目的比较不同浓度的舒芬太尼与罗比卡因复合应用于术后病人自控硬膜外镇痛（PCEA）中的镇痛效果及相关不良反应.方法36例择期全子宫切除术后的病人随机双盲均分为三组,术后硬膜外镇痛分别使用0.3 μg/ml（A组）、0.4 μg/ml（B组）和0.5 μg/ml（C组）的舒芬太尼复合0.125%罗比卡因.镇痛泵设定持续输注背景剂量2 ml/h,PCA量每次3 ml,锁定时间30 min.分别于术后4、8、20、24、48 h观察病人的视觉模拟评分（VAS评分）、镇痛药的使用剂量、PCA的按压次数及不良反应.结果随着舒芬太尼浓度的增加,VAS评分、镇痛药用量、PCA按压次数逐渐下降,PCA按压次数比逐渐上升,术后4、8 h A组的VAS评分高于B组和C组（P〈0.05或0.01）,术后20 h A组的VAS评分高于C组（P〈0.01）.术后4 h A组的镇痛药用量及PCA按压次数高于C组（P〈0.05）.A组术后镇静、恶心、呕吐及皮肤瘙痒发生率低于C组（P〈0.05）.结论舒芬太尼与罗比卡因复合应用于术后病人PCEA中的镇痛效果明确,不良反应发生率低.0.4 μg/ml舒芬太尼与0.125%罗比卡因相配伍在获得满意镇痛效果的同时,引起相对少的不良反应,更适合在临床应用中推广.     

老年患者全髋置换术后舒芬太尼静脉和硬膜外自控镇痛的可行性

目的 观察老年患者全髋置换术后舒芬太尼静脉自控镇痛（PCIA）和硬膜外自控镇痛（PCEA）的安全性和有效性。方法 择期硬膜外麻醉下全髋置换术后老年患者50例，ASAⅠ—Ⅲ级，年龄65—96岁，随机分为2组（n=25），舒芬太尼PCIA组和舒芬太尼PCEA组。应用Graseby9500电子镇痛泵，PCIA组和PCEA组药物配伍相同，即舒芬太尼250μg＋氟哌利多5mg混合液100ml，两组PCA均采用负荷量-持续背景量-PCA量模式：负荷剂量5μg，背景剂量1μg／h。PCA追加剂量2．5μg，锁定时间3min。患者术后自觉疼痛时（VAS评分〉0）进行镇痛，记录给负荷剂量后0、4、8、20、24和48h时舒芬太尼累积用量、按压次数（D1）、实进次数（D2）、血压（BP）、心率（HR）、呼吸频率（RR）、脉搏血氧饱和度（SpO2）、VAS评分、Ramsay评分、不良反应和治疗措施。计算术后第2天舒芬太尼累积用量。结果PCIA组术后第1天舒芬太尼累积用量、D1和D2多于PCEA组（P〈0．01）。两组镇痛期间VAS评分、术后第2天舒芬太尼累积用量、不良反应发生率差异无统计学意义（P〉0．05），Ramsay评分均为2分（P〉0．05）。结论 老年患者全髋簧换术后舒芬太尼PCIA与PCEA均安全有效，舒芬太尼PCIA用量较PCEA多。     

胸科手术后舒芬太尼静脉镇痛的剂量探讨

目的探讨普胸外科手术后舒芬太尼静脉镇痛的合理剂量和效果。方法80例普胸外科手术后的病人均分为四组，A组（芬太尼30μg／h），B组（舒芬太尼3μg／h），C组（舒芬太尼4μg／h），D组（舒芬太尼5μg／h）。观察术后4、8、16、24、48h的疼痛、镇静、情绪、睡眠质量评分，并记录有无恶心、呕吐、呼吸抑制、皮肤瘙痒等不良反应，记录镇痛泵输注情况、（实际／有效）按压次数，计算单位时间实际用药量。结果四组间镇静、睡眠质量评分以及不良反应差异无统计学意义，D组疼痛评分显著低于其他三组（P〈0．05），PCA泵按压次数最少，B、C、D组单位时间实际药量大致相近。结论普胸外科手术后舒芬太尼静脉镇痛的最佳剂量为5μg／h，且恒速背景输注比反复追加给药更容易为病人所接受。     

子宫切除术后不同浓度舒芬太尼混合左旋布比卡因病人硬膜外自控镇痛的效果

目的 评价不同浓度舒芬太尼与左旋布比卡因混合用于经腹子宫切除术后病人硬膜外自控镇痛（PCEA）的效果。方法 择期经腹行子宫切除术病人90例，年龄41～64岁，ASAⅠ或Ⅱ级，随机分为3组（n=30）：Ⅰ组（舒芬太尼0．4μg／ml配伍0．2％左旋布比卡因）、Ⅱ组（舒芬太尼0．5μg／ml配伍0．2％左旋布比卡因）、Ⅲ组（舒芬太尼0．6μg／ml配伍0．2％左旋布比卡因）。均采用LCP模式给药，负荷剂量5ml，持续剂量1ml／h，单次给药剂量2ml，锁定时间10min，全程镇痛24h。观察和记录病人PCA泵开启时和开启后4、8、16、20、24hMAP、HR、视觉模拟法（VAS）评分、Ramsay评分、总按压次数／实际有效进药次数（D1／D2）比值及术后恶心、呕吐等不良反应发生情况。结果 与Ⅰ组比较，Ⅱ组、Ⅲ组PCA泵开启后8、12hVAS评分降低（P〈0．05）；3组术后镇痛期间未按压的例数Ⅰ组最少，Ⅲ组最多（P〈0．05）；3组按压次数〉9次的例数Ⅲ组最少（P〈0．05）；D1／D2比值Ⅰ组高于Ⅱ组、Ⅲ组。Ⅰ组有4例需硬膜外追加吗啡，Ⅰ组发生低血压1例，Ⅱ组发生头晕1例。3组均未发生恶心、呕吐、呼吸抑制等不良反应。结论 舒芬太尼0．6μg/ml与0．2％左旋布比卡因混合用于经腹子宫切除术后PCEA效果满意，且不良反应发生率低。     

不同剂量舒芬太尼用于术后硬膜外自控镇痛比较

目的对比观察不同剂量的舒芬太尼用于术后硬膜外自控镇痛的效果及出现不良反应情况。方法选择60例子宫全切手术病人,根据自控镇痛泵配制预定舒芬太尼剂量不同,随机分为3组,每组20例,即：A组舒芬太尼为1.5μg/kg,B组舒芬太尼为2.0μg/kg,C组舒芬太尼为2.5μg/kg。3组镇痛泵中均加布比卡因100 mg＋氟哌利多2.5 mg至生理盐水100 mL中。结果 A组镇痛效果欠佳,与B和C 2组相比存在着明显差异性（P〈0.05）,但C组出现不良反应症状略多于A和B 2组。结论 B组具有镇痛效果好,且不良反应少,是舒芬太尼用于术后硬膜外自控镇痛的最佳剂量。     

舒芬太尼与丁丙诺啡在口腔外科术后镇痛的比较

目的 比较等效剂量丁丙诺啡与舒芬太尼在口腔外科术后镇痛的效果.方法 60例ASAⅠ或Ⅱ级口腔外科术病人依病历号奇偶数分为舒芬太尼组(S)与丁丙诺啡组(B),每组30例.两组均采用静脉自控镇痛(PCIA)给药,S组舒芬太尼50μg,B组丁丙诺啡0.6 mg,总量100 ml,首次负荷剂量4 ml.术后5、10、20及40 h行VAS疼痛与Ramsay运动评分,记录PCA有效按压次数及不良反应发生率.结果 两组VAS疼痛评分、Ramsay运动评分及PCA有效按压次数差异均无统计学意义,而不良反应发生率B组显著高于S组(P<0.05或P<0.01).结论 等效剂量舒芬太尼与丁丙诺啡用于口腔外科术后镇痛效果相当,但舒芬太尼不良反应发生率较低,更适合口腔外科术后镇痛使用.     

肝脏术后舒芬太尼病人自控镇痛对胃肠动力的影响

目的评价舒芬太尼自控镇痛对肝脏手术病人术后胃肠动力的影响。方法择期肝脏手术病人30例,ASAⅠ级或Ⅱ级,年龄18～64岁,随机分为3组,每组10例,B组应用0．25％布比卡因术后病人自控硬膜外镇痛,BS组应用0．125％布比卡因混合0．4μg/ml舒芬太尼术后病人自控硬膜外镇痛,S组应用0．8μg/ml舒芬太尼术后病人自控静脉镇痛。B组和BS组背景剂量4 ml/h、PCEA剂量4 ml/次,锁定时间10 min;S组背景剂量2．5 ml/h、PCIA剂量5 ml/次,锁定时间8 min。记录3组术后48 h胃肠消化间期移行性复合运动（MMC）、病人术后排气时间、胃肠引流量、术后24、48 h VAS评分及住院时间,观察循环、呼吸变化及不良反应。结果术后30 min内所有病人MMC均消失,术后30 min后出现的MMC仅由Ⅰ相和Ⅲ相构成,缺乏MMCⅡ相。B组MMCⅢ相的曲线下面积最大,收缩持续时间最长,收缩幅度最高（P＜0．05）。3组病人均镇痛良好,BS组术后48 h VAS评分最低（P＜0．05）。与B组比较,BS组和S组低血压发生率降低（P＜0．05）。结论与布比卡因硬膜外镇痛相比,肝脏术后病人舒芬太尼硬膜外或静脉镇痛时胃肠动力的恢复延迟。     

氟比洛芬酯复合舒芬太尼用于老年患者术后镇痛的效果

目的 探讨氟比洛芬酯复合舒芬太尼用于老年患者术后镇痛的安全性和有效性,并找出合适的用药方法.方法 行择期上腹部手术患者60例,年龄65～85岁,ASAⅠ或Ⅱ级,随机均分为四组.A组:术毕缝皮时静注氟比洛芬酯50 mg,术后PCA镇痛液中含舒芬太尼100 μg.B组:术后PCA镇痛液中含氟比洛芬酯150 mg,舒芬太尼75 μg.C组:术毕缝皮时静注氟比洛芬酯50 mg,术后PCA镇痛液中含氟比洛芬酯150 mg,舒芬太尼50 μg.D组:术毕缝皮时不给予氟比洛芬酯,术后PCA镇痛液中含舒芬太尼100 μg.分别记录苏醒后、术后4、8、12、24 h VAS评分,Ramsay镇静评分,术后不同时点PCA泵按压次数、实际有效按压次数,术后24 h舒芬太尼累积用量以及不良反应,记录苏醒时间、拔管时有无躁动、咽痛.结果 与A、C组比较,T0～T2时B、D组VAS评分明显升高(P<0.05).与B、C组比较,T1、T2时A、D组Ramsay评分明显升高(P<0.05).与A、C组比较,B、D组PCA实际、有效按压次数明显增多(P<0.05).与C组比较,术后24 h内A、B、D组舒芬太尼用量明显增多(P<0.05).结论 老年患者行上腹部手术术毕缝皮时静注氟比洛芬酯50 mg,术后PCA镇痛液中含氟比洛芬酯1.50 mg/ml、舒芬太尼0.50 μg/ml,术后镇痛效果好,不良反应少.     

不同剂量舒芬太尼复合曲马多用于烧伤患儿术后镇痛的比较

目的比较不同剂量舒芬太尼复合曲马多用于烧伤患儿术后静脉镇痛(PCIA)的效果,并探讨舒芬太尼适宜剂量。方法拟于全身麻醉下择期行躯干或四肢烧伤瘢痕整形术患儿60例,年龄3~10岁,ASAⅠ或Ⅱ级,随机均分为A、B、C组。术毕前30min给予负荷量舒芬太尼0.15μg/kg,术后接镇痛泵,其中A组舒芬太尼0.03μg·kg-1·h-1,B组舒芬太尼0.04μg·kg-1·h-1,C组舒芬太尼0.05μg·kg-1·h-1;三组均复合曲马多0.3mg·kg-1·h-1。分别在术后即刻(T1)、6h(T2)、12h(T3)、24h(T4)和48h(T5)采用改良面部表情评分法观察镇痛效果,记录FLACC评分和Ramsay镇静评分。观察并记录PCA按压次数及呼吸抑制、恶心、呕吐、头晕等不良反应。结果与A组比较,T2~T5时B组和C组面部表情评分、FLACC评分明显降低、Ramsay镇静评分明显升高(P0.05)。B组和C组面部表情评分、FLACC评分和Ramsay镇静评分差异均无统计学意义。与A组比较,B组和C组PCA有效按压次数明显减少,C组恶心呕吐、头晕发生率明显升高(P0.05)。与B组比较,C组PCA有效按压次数明显减少、恶心呕吐、头晕发生率明显升高(P0.05)。结论舒芬太尼0.04μg·kg-1·h-1复合曲马多0.3mg·kg-1·h-1用于小儿术后镇痛效果较好,不良反应少。     

帕瑞昔布钠与舒芬太尼在肛肠病术后镇痛的应用

为比较帕瑞昔布钠和舒芬太尼联合应用与单纯应用舒芬太尼在肛肠病术后的镇痛效果和不良反应,将肛肠病术后病人120例随机分为帕瑞昔布钠组和对照组各60例。手术结束时帕瑞昔布钠组静脉注射帕瑞昔布钠40mg和舒芬太尼1．00pg／ml行静脉自控镇痛（PCIA）,12h后帕瑞昔布钠组再静脉注射帕瑞昔布钠40mg;对照组单纯应用舒芬太尼1．50μg／ml行PCIA。观察两组病人术后2,4,6,12h和24h的疼痛强度（VAS评分）、镇痛的补救以及不良反应的发生率。结果显示,与对照组相比,帕瑞昔布钠组术后舒芬太尼用最减少,不良反应发生率降低,术后24h镇痛满意度明显提高（P〈0．05）,而两组12h和24h VAS评分无显著性差异（P〉0．05）。结果表明,肛肠病术后静脉注射帕瑞昔布钠可减少术后舒芬太尼的用量,提高病人术后镇痛效果。     

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.