乌司他丁对心脏瓣膜置换术患者体外循环期间全身炎性反应的影响

目的 探讨乌司他丁对心脏瓣膜置换术患者体外循环期间全身炎性反应的影响.方法 拟行心脏瓣膜置换术的风湿性心脏病患者40例,性别不限,体重39～72kg,年龄27～44岁,ASAⅡ或Ⅲ级,随机分为2组(n=20):对照组(C组)和乌司他丁组(U组).U组于CPB前10 min静脉注射乌司他丁1万U/kg,CPB预充液中加入1万U/kg,C组以等容量生理盐水替代乌司他丁.于CPB前15 min(T1)、CPB 10 min(T2)、CPB结束后30 min(T3)、60 min(T4)时测定血浆白细胞介素6(IL-6)、IL-8、IL-10及肿瘤坏死因子α(TNF-α)的浓度.结果 与C组比较,U组CPB期间和CPB结束后血浆IL-6、IL8和TNF-α的浓度降低,IL-10浓度升高(P<0.05或0.01);与T1比较,T2,3时两组血浆IL-6、IL-8、IL-10、TNF-α的浓度升高(P<0.01).结论 乌司他丁可减低心脏瓣膜置换术患者CPB期间促炎-抗炎反应失衡,减轻全身炎性反应.     

依达拉奉联合乌司他丁对心脏瓣膜置换术患者脑保护的作用

目的 探讨依达拉奉联合乌司他丁对心脏瓣膜置换术患者围心肺转流(CPB)期脑保护的作用.方法 择期心脏瓣膜置换术患者40例,随机均分为四组.E组于麻醉诱导后静脉滴注依达拉奉0.5 mg/kg,U组于麻醉诱导后静注乌司他丁1.2万U/kg,EU组按照E组和U组的用药量及方法联合给药;C组用等容量生理盐水代替.分别于麻醉后用药前(T0)、主动脉开放后10 min(T1)、4 h(T2)及24 h(T3)采集颈静脉球部血,检测丙二醛(MDA)、超氧化物歧化酶(SOD)、总抗氧化能力(T-AOC)、肿瘤坏死因子α(TNF-α)、白细胞介素(IL)-6、IL-10、神经组织蛋白(S-100β)及神经元特异性烯醇化酶(NSE),并观察术后神经精神并发症的发生情况.结果 与C组比较,T1、T2时E、U、EU组TNF-α、IL-6、MDA、S-100β及NSE降低,IL-10、SOD及T-AOC升高(P＜0.05);与EU组比较,T1、T2时U组TNF-α、IL-6、MDA、S-100β及NSE均升高,IL-10降低(P＜0.05);E组TNF-α、IL-6升高,IL-10降低(P＜0.05);与U组比较,T1、T2时E组TNF-α、IL-6升高,IL-10、MDA降低(P＜0.05).术后随访无谵妄及神经系统阳性体征.结论 依达拉奉联合乌司他丁用于心脏瓣膜置换术麻醉,有利于抑制炎症因子、氧自由基及其他细胞因子之间网络式的级联放大效应,减轻围CPB期脑损伤;其脑保护效应比单用依达拉奉或乌司他丁更具有优势.     

乌司他丁对心肺转流患者血浆S-100β蛋白、炎性因子及认知功能的影响

目的 观察乌司他丁对心肺转流(CPB)下瓣膜置换术患者血浆S-100β蛋白、炎性细胞因子及认知功能的影响.方法 择期行瓣膜置换术患者40例,随机均分为乌司他丁组(U组)和对照组(C组).U组于切皮前静脉注射乌司他丁10 000 U/kg,并在预充液中加入10 000 U/kg;C组给予等容量生理盐水.于给药前(T1)、CPB结束后即刻(T2)、2 h(T3)、6 h(T4)及24 h(T5)抽取颈内静脉血测定血浆IL-6、TNF-α浓度及S-100β蛋白;于麻醉前1d和术后1、3、7d对患者进行评分并判断是否发生术后认知功能障碍(POCD).结果 与T1时比较,T2～T5时两组血浆S-100β蛋白及IL-6、TNF-α浓度均升高(P＜0.05);与C组比较,U组中的S-100β蛋白及IL-6、TNF-α浓度显著降低(P＜0.01);U组2例、C组7例发生POCD( P＜0.05).结论 乌司他丁可减轻瓣膜置换术患者CPB时炎性介质的释放,降低患者术后POCD的发生率.     

乌司他丁对心肺转流心内直视术中细胞因子平衡和心肌细胞凋亡的影响

目的探讨乌司他丁对心肺转流(CPB)心内直视术患者细胞因子平衡和心肌细胞凋亡的影响。方法20例择期行二尖瓣置换术患者,随机均分为乌司他丁组(U组)和对照组(C组)。U组给予乌司他丁100万U,其中1万U于转机前静注作过敏试验,99万U加入预充液中;C组用生理盐水代替。于转机前(T0)、转机30min(T1)、CPB停止即刻(T2)、CPB停止后2h(T3)、6h(T4)和24h(T5)采集动脉血,测定血浆肿瘤坏死因子α(TNF-α)、白细胞介素-6(IL-6)、白细胞介素-8(IL-8)和白细胞介素-10(IL-10)浓度。采用TUNEL法测定两组CPB前和CPB停止后30min右心房的心肌凋亡细胞。结果U组T2~T5时的IL-6、IL-8和TNF-α浓度明显低于C组(P<0·01),而IL-10浓度明显高于C组(P<0·01)。CPB停止后30min,U组心肌细胞的凋亡指数明显低于C组(P<0·05)。结论乌司他丁抑制CPB期间TNF-α、IL-6和IL-8的释放,促进IL-10的释放,有利于细胞因子反应平衡的调节;乌司他丁通过抑制细胞凋亡,减少心肌细胞的死亡,可有效的保护心肌。     

乌司他丁后处理及其联合预先给药对CPB下心脏瓣膜置换术患者心肌炎性反应的影响

目的 评价乌司他丁后处理及其联合预先给药对CPB下心脏瓣膜置换术患者心肌炎性反应的影响.方法 择期行CPB下心脏瓣膜置换术患者80例,性别不限,年龄21～59岁,心功能分级Ⅱ或Ⅲ级.采用随机数字表法,将患者随机分为4组(n=20):生理盐水对照组(C组)、乌司他丁预先给药组(U1组)、乌司他丁后处理组(U2组)和乌司他丁预先给药联合后处理组(U3组).U1组于气管插管后至升主动脉阻断前10 min经中心静脉输注乌司他丁500～ 1000 U·kg-1·min-(剂量20 000U/kg);U2组于主动脉开放前5～7 min经主动脉根部灌注乌司他丁4000～5000 U·kg-1·min-1(剂量10 000 U/kg);U3组进行乌司他丁预先给药联合后处理;C组给予等容量生理盐水.分别于升主动脉阻断前10 min(T1)、升主动脉阻断后40 min(T2)、主动脉开放后45 min(T3)和术毕(T4)时采集动脉血样,测定血浆IL- 10、IL-1、IL-6和TNF-α的浓度,并进行中性粒细胞(PMN)计数.于主动脉开放后45min时取右心耳组织,采用免疫组化法测定IL-6和IL-1β的表达.结果 与C组比较,U1组、U2组和U3组血浆IL-10浓度升高,血浆IL-1、IL-6、TNF-α的浓度和PMN计数降低,心肌组织IL-1β和IL-6表达下调(P＜ 0.05);与U1组和U2组比较,U3组T2-4时血浆IL-10浓度升高,血浆IL-1、IL-6、TNF-α的浓度和PMN计数降低,心肌组织IL-1β和IL-6表达下调(P＜0.05).结论 乌司他丁后处理可抑制CPB下心脏瓣膜置换术患者心肌炎性反应,联合预先给药时其效应增强.     

患儿法洛四联症矫治术中乌司他丁对脑损伤S100β蛋白和神经元特异性烯醇化酶的影响

目的观察乌司他丁对患儿法洛四联症(tetralogy of Fallot,TOF)矫治术中血浆中S100β蛋白和神经元特异性烯醇化酶(NSE)浓度的影响。方法选择择期行心肺转流(cardiopulmonary bypass,CPB)下一期矫治术的TOF患儿40例,男25例,女15例,3～12月龄,采用密封随机分组信封法分为两组:乌司他丁组(U组)和对照组(C组),每组20例。两组麻醉诱导、维持及围术期用药相同,U组麻醉诱导后静脉给予乌司他丁10 000U/kg,CPB预充液中加入20 000U/kg;术后第1天开始应用乌司他丁30 000U·kg~(-1)·d~(-1),直至出ICU时停药。记录患儿CPB时间,并于诱导时(T1)、停CPB(T2)、术后24h(T3)、术后48h(T4)抽取静脉血3ml,采用ELISA法测定血浆中S100β蛋白和NSE浓度。结果 T1时两组S100β蛋白及NSE浓度均在正常范围内。与T1时比较,T2时两组S100β蛋白和NSE浓度明显升高(P0.05),且达到峰值;T3—T4时两组S100β蛋白浓度明显下降(P0.05);T3时两组NSE浓度降低,T4时基本恢复至T1时水平。结论在TOF患儿CPB术中,乌司他丁可降低血浆中脑损伤标志物S100β蛋白和NSE浓度,从而产生一定的脑保护作用。     

氯胺酮对体外循环心脏手术患者血浆S100-β蛋白及炎性因子的影响

目的 观察氯胺酮对体外循环(CPB)心脏手术患者血浆S100-β蛋白及炎性介质肿瘤坏死因子-a(TNF-α)、白细胞介素-6(IL-6)的影响.方法 择期行二尖瓣置换术患者40例,ASA Ⅱ或Ⅲ级,随机分为氯胺酮组(K组)和对照组(C组),每组20例.常规全麻诱导后,K组以氯胺酮2mg/kg静脉注射,继之以50μg·kg-1·min-1的速度持续泵注至手术结束,C组给予等量生理盐水.分别于麻醉诱导后(氯胺酮注射前,T1)、CPB后20 min(T2)、CPB结束时(T3)、术毕(T4)、术后24 h(T5)时抽取颈静脉球部血,测定各时点血浆S100-β、TNF-α及IL-6浓度,并对S100-β与TNF-α、IL-6之间的相关性进行分析.结果 与T1时比较,T2时两组患者血浆TNF-α、IL-6显著升高,T4达到高峰,T5时明显下降但仍高于T1时(P<0.05).T2～T5时K组TNF-α均显著低于C组(P<0.05).T2～T4时K组IL-6显著低于C组(P<0.05).T2时两组患者血浆S100-β浓度较T1时显著升高;T3时达到高峰,T5时显著下降但仍高于T1时(P<0.05).与C组比较,T2～T5时K组S100-β均显著降低(P<0.05).T2～T5时S100-β与TNF-α有明显的相关性(r-分别为0.815,0.791,0.684,0.572,P<0.05);T2～T4时S100-β与IL-6有明显相关性(r分别为0.785,0.824,0.703,P<0.05).结论 CPB心脏手术期间应用麻醉剂量的氯胺酮可明显降低CPB诱发的TNF-α、IL-6及S100-β蛋白的升高.     

乌司他丁减轻心肺转流脑损伤的研究

目的探讨围麻醉期乌司他丁对心肺转流(CPB)下行心脏手术患者脑部炎性反应的影响及其脑保护作用。方法择期心脏瓣膜置换患者24例,随机均分为乌司他丁组(U组)和对照组(C组)。U组患者在麻醉后和转机时分别静脉泵注乌司他丁,泵注时间均为1h。C组患者则给予等量容积的生理盐水代替。分别于麻醉后手术前(T1),CPB开始后30min(T2),CPB结束后1h(T3),4h(T4)和20h(T5)抽取颈静脉球血,采用ELISA法测定颈静脉球血白细胞介素-6(IL-6)、中性粒细胞弹性蛋白酶(PMNE)和S100B蛋白的浓度。结果与T1相比,两组患者颈静脉球血中IL-6、PMNE的浓度在T2～T5时明显升高(P<0.05或P<0.01),且C组升高的幅度明显大于U组(P<0.05或P<0.01)。与T1时相比,两组血浆S100B蛋白水平在CPB开始后明显升高(P<0.01),T3时达到高峰,T4时开始下降,T5时明显下降。U组T2～T5时的S100B蛋白浓度升高的水平明显低于C组(P<0.01)。结论乌司他丁可减轻CPB心脏手术患者脑局部炎性反应,可降低颈静脉球血中S100B蛋白水平升高的幅度,具有一定的脑保护作用。     

α-硫辛酸对体外循环诱发犬脑损伤的影响

目的 探讨α-硫辛酸对体外循环诱发犬脑损伤的影响.方法 健康杂种犬12只,雌雄不拘,体重13.5～17.5kg,随机分为对照组(C组)和α-硫辛酸组(L组),每组6只.L组于CPB前即刻静脉注射α-硫辛酸50 mg/kg,C组静脉注射等容量生理盐水.全心缺血60 min,恢复灌注60 min.分别于阻断升主动脉前(T0)、阻断升主动脉30、60 min、再灌注30、60 min(T1-4)时取股静脉血样,采用酶联免疫吸附双抗体夹心法测定血清TNF-α、S100β蛋白及神经元特异性烯醇化酶(NSE)的浓度.结果 与T0时比较,两组T1～4时血清TNF-α浓度、T2-4时NSE浓度、C组T1-4时S100β蛋白浓度升高(P＜0.05);与C组比较,L组T1～4时血清TNF-α、S100β蛋白浓度、T2～4时NSE浓度降低(P＜0.05).C组血清TNF-α与S100β蛋白、NSE浓度成正相关(r=0.706,P＜0.01;r=0.81,P＜0.01).结论 α-硫辛酸可减轻体外循环诱发的犬脑损伤,与其抑制炎性反应有关.     

1,6-二磷酸果糖对心肺转流心脏手术脑损伤的影响

目的观察1,6二磷酸果糖(FDP)对心肺转流(CPB)心脏手术病人脑损伤的影响。方法选择24例择期行心脏瓣膜置换术病人,随机分为FDP组(F组)和对照组(C组),每组12例。于麻醉后手术前(T1)、复温至36℃(T2)、停CPB30min(T3)、停CPB6h(T4)抽取颈静脉球血,测定S100β蛋白和神经元特异性烯醇化酶(NSE)的含量。结果两组S100β蛋白与NSE在T2至T4时均比T1时有明显升高(P<0.01),但T3至T4时F组S100β蛋白与NSE明显低于C组(P<0.05或P<0.01)。结论FDP可以减轻CPB心脏手术病人的脑损伤。     

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.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.