血清对肺表面活性物质功能的影响

目的探讨血清对肺表面活性物质(PS)功能的影响.方法用血清将PS稀释溶解配制成2.0、4.0、6.0、8.0、10、l2、24mg/ml的实验液体.同时作为对照将PS溶解于醋酸林格液中配成相同的浓度.用表面张力计测定实验液体的表面张力.未成熟胎兔36只随机分为4组(每组9只)A组,经气道内注入溶解于醋酸林格液的PS24mg/ml;B组,注入溶于血清的PS24mg/ml;C组,注入溶于醋酸林格液的PS4.0mg/ml;D组,未注入任何物质,进行人工通气.通气后5、10、15、20min测定动物的潮气量.结果溶解于醋酸林格液的PS浓度在2.0mg/ml时,最小表面张力(γmin)小于3.0mN/m.溶剂为血清时,γmin增至30mN/m(P＜0.01).PS的浓度增加到6.0mg/ml时,γmin降至9.0mN/m.人工通气20min时,A组动物的潮气量大于15ml/kg,而B组小于8.0ml/kg(P＜0.05),C组未超过5.0ml/kg,D组未超过2.0ml/kg.结论血清明显抑制PS的功能,抑制程度与PS剂量有关.     

肺表面活性物质对胎粪吸入鼠肺功能的影响

目的：探讨外源性肺表面活性物质（PS）对胎粪吸入鼠肺功能的影响。方法：28只Wistar大白鼠进行人工通气，经气道注入3－4ml/kg胎粪溶液，PaO2降至20kPa以下后将动物随机分为4组（每组7只）。A组，气道内注入PS 150mg/kg(50mg/ml,3ml/kg)；B组，气道内注入等量生理盐水；C组，用PS稀溶液75mg/kg(5mg/ml,15ml/kg)进行支气管肺泡灌洗，重复2次；D组，用15ml/kg的生理盐水灌洗双肺。治疗后15min,30min,60min,120min,180min采血进行血气分析。180min后测定各组潮气量，并进行支气管肺泡灌洗（BAL），检测BAL液中总蛋白（TP）和TNF－α含量。结果：治疗后A和C组PaO2均明显升高，而B和D组在治疗后几乎不变，A、C组与B、D组相比，P＜0．05。A与C组间差异均无显著性。A和C组的潮气量明显高于B和D组（P＜0．05）。A和C组的BAL液中TP含量明显低于B和D组（P＜0．05）。TNF－α含量各组间无差异。结论：补充PS明显改善胎粪吸入鼠肺的氧合和顺应性。PS稀溶液灌洗法优于气道注入法。     

利多卡因-肺表面活性物质混合液对洗肺鼠呼吸衰竭的作用

目的　探讨利多卡因 (Li) 肺表面活性物质 (PS)混合液对洗肺鼠呼吸衰竭的作用。方法　 2 8只Wistar大鼠戊巴比妥钠腹腔内注射麻醉后 ,经气管切开孔插入导管行人工呼吸 ,吸气峰压(Ppeak)定为 1 4 7kPa ,吸呼比为 1∶1。将Ppeak及呼气末正压 (PEEP)分别调至 1 96kPa和 0 4 9kPa后 ,对所有动物行全肺灌洗 (生理盐水 3 7℃ ,4 0ml/kg) 8～ 10次。当动脉血氧分压 (PaO2 )降至 12kPa以下时 ,将动物随机分成四组 ,每组 7只。A组 :气管内注入Li( 2 5mg ,0 5ml) ;B组 :气管内注入PS( 2 5mg ,0 5ml) ;C组 :气管内注入PS( 2 5mg)与Li( 2 5mg)的混合液 0 5ml;D组 :气管内注入生理盐水 0 5ml。 12 0分钟后撤离PEEP ,并将Ppeak调至 1 4 7kPa ,测定动脉血气值、乳酸盐浓度及潮气量。结果　所有动物PaO2 经灌洗后由 5 5 0 7kPa降至 9 4 7kPa(P <0 0 5 )。治疗后A、B、C组的PaO2 均明显升高 (与灌洗后比较 ,P <0 0 5 ) ,以B、C组的升高显著 (恢复至灌洗前水平 ) ,但D组始终保持在8 8kPa以下。撤离PEEP后 ,A、B组PaO2 降至 18 8kPa以下 ,C组则一直维持在治疗后水平 (与其它三组比较 ,P <0 0 5 )。撤离PEEP后C组的乳酸盐浓度均低于其他三组 ,而平均动脉压明显高于其他三组。结论　Li PS混合液能改善洗肺鼠的呼     

肺表面活性物质对酸奶误吸鼠呼吸衰竭的作用

目的：探讨肺表面活性物质（PSD）对酸奶误吸鼠呼吸衰竭的作用。方法：33只Wistar大鼠在人工呼吸下经气道注入酸牛奶。当动脉血氧分压（PaO2）降至13.3kPa以下时，将动物随机分成三组。Ⅰ组（n=11）为对照组，气道内未注入任何物质，Ⅱ组（n=11)在附加0.49kPa呼气末正压（PEEP）30min后经气道注入PS（200mg/kg)；Ⅲ组（n=11）在附加PEEP的同时经气道注入等量PS。测定并记录动脉血气值、潮气量等。结果：注入酸奶后所有动物的PaO2均明显下降。自分组后Ⅰ组的PaO2未见改善；Ⅱ组的PaO2在PS注入后逐渐升高，（与Ⅰ组比较，P＜0．05）；Ⅲ组的PaO2在PS注入后显著升高，（与Ⅰ、Ⅱ组比较，P＜0．05）。动脉血二氧化碳分压（PaCO2）、潮气量等在Ⅰ组未见明显变化，而Ⅱ组及Ⅲ组均有明显改善，尤以Ⅲ组更显著。结论：气道内注入酸奶能导致呼吸衰竭，单纯应用附加PEEP的人工呼吸不能明显改善此种严重的低氧血症；PS补充疗法能明显改善肺功能，且以PS早期治疗效果更明显。     

肺表面活性物质及呼气末正压对呼吸衰竭的作用

目的　探讨肺表面活性物质 (PS)在不同呼气末正压 (PEEP)下对洗肺鼠呼吸衰竭的作用。方法　 5 6只Wistar大鼠 (体重 30 0～ 35 0 g)在戊巴比妥钠 (30mg/kg)腹腔内麻醉下人工呼吸并用生理盐水洗肺 ,共洗 8～ 11次 ,洗肺期间吸入峰压及PEEP分别调至 2 5cmH2 O和 7 5cmH2 O。当PaO2 降至 90mmHg以下时 ,随机分为八组 ,每组 7例。 1～ 4组经气道注入PS 2 5mg(0 5ml) ,5～ 8组则经气道注入等量的生理盐水 (0 5ml)。 1组和 5组的PEEP为 7 5cmH2 O ,2组和 6组的PEEP为5cmH2 O ,3组和 7组的PEEP为 2 5cmH2 O ,4组和 8组的PEEP为 0cmH2 O。结果　未注入PS的 5～ 8组的PaO2 在整个实验中未见明显变化 ,均在 10 0mmHg以下。注入PS的 1～ 4组中 ,无PEEP的第 4组及 2 5cmH2 OPEEP的第 3组的PaO2 未见明显改善 ,与 5～ 8组之间未见显著差异 (P >0 0 5 )。第 2组的PaO2 虽在注入PS后 15分钟明显升高至 (34 3 5 3± 132 2 6 )mmHg ,但以后逐渐下降至治疗前水平。只有第 1组的PaO2 在治疗后显著的升高至 40 0mmHg以上 (P <0 0 5 ) ,并维持此高值至实验结束。结论　单独PEEP不能改善洗肺鼠的低氧血症 ,补充PS并附加 7 5cmH2 O的PEEP可明显改善低氧血症     

外源性肺泡表面活性物质对大鼠呼吸机相关性肺损伤的保护作用

目的探讨气管注入肺泡表面活性物质(PS)对大鼠呼吸机相关性肺损伤(VILI)的保护作用及机制。方法将40只Wistar大鼠采用区组法随机分为对照组、高潮气量组(HV组)、VILI组和PS组4组,每组各10只。对照组未行机械通气,其余3组容量控制通气,PS组同时经气管内插管注入猪PS100mg/kg。监测心率、平均动脉压(MAP)、血气分析、肺湿/干重比(W/D)和支气管肺泡灌洗液(BALF)中白细胞计数,测定肺组织核因子-κB(NF-κB)活性和BALF中及血清白细胞介素-8(IL-8)浓度,并观察大体及光学显微镜下肺组织损伤的改变。结果损伤性机械通气后大鼠MAP及氧合指数(PaO2/FiO2)显著降低,而肺组织NF-κB活性和W/D显著增高。PS组与VILI组相比,MAP、PaO2/FiO2、肺组织NF-κB活性、BALF中白细胞计数、BALF及血清中IL-8浓度均有统计学意义(P<0.05)。组织学检查显示PS组较VILI组病变明显减轻。结论经气管注入PS可抑制VILI大鼠NF-κB基因表达,对VILI有保护作用。     

应用改良的葡萄糖-胰岛素-钾溶液治疗大面积烧伤的实验研究

作者应用一种改良的葡萄糖-胰岛素-钾(GIK)溶液治疗犬大面积烧伤,试图减轻烧伤后产生的心肌抑制因子(MDF)对心肌功能的影响。其改良的GIK溶液最大输入速度及比例,葡萄糖为400mg/m~2/min,胰岛素为1200ml/m~2/min,氯化钾为0.08mEq/m~2/min。麻醉下给予犬胸腹部(占体表面积50％)Ⅲ度火焰烧伤以后,即按Parkland烧伤补液公式计算经静脉输入乳酸林格液(0.25ml/kg/％烧伤/h,直至伤后8小时实验结束)。将动物随机分为三组进行治疗:A组单纯输入乳酸林格液;B组乳酸林格液加50％葡萄糖液(400mg/m~2/min,伤后1.5小时开始静脉点滴输入);C组乳酸林格液加改良GIK溶液(伤后2     

超氧化物歧化酶-肺表面活性物质脂质体的肺保护作用

我们利用高氧性肺损伤动物模型可以为预防和治疗体外循环后的肺损伤提供实验基础。一、材料与方法1.制备超氧化物歧化酶 肺表面活性物质(SOD PS)脂质体:PS 1ml加乙醚3ml和甲醇1ml ,再加入SOD 80 0 0U。在水浴型超声波清洗器上振荡2次,每次10～15min ,间隔5min ,然后减压蒸发掉有机溶剂,加磷酸盐缓冲液(PBS)至2ml,振荡形成水溶性悬液,即SOD PS脂质体。2 .预处理动物:Wistar大鼠40只,体重(2 5 6.7±3 9.0 )g ,随机分为5组。腹腔注射10 %水合氯醛3 .5～4.0ml/kg体重镇静麻醉动物,颈部正中切口暴露气管,分别注入实验液:SOD PS脂质体2m…     

SP-C对重组肺表面活性物质活性的影响

目的 探讨不同浓度的肺表面活性物质(PS)相关蛋白C(SP-C)与合成脂质构成的重组PS活性的变化。方法 从新鲜猪肺的灌洗液中提取PS,从PS中分离出SP-C。将二棕榈酰磷脂酰胆碱、二油酰磷脂酰胆碱和棕榈酰油酰磷脂酰甘油按60:20:20的重量比混合,即为合成脂质(SL),将SP-C按1％、2％、3％(与脂质的重量比)加入SL中,制成三种重组PS:RS-1、RS-2和RS-3。将上述物质溶于生理盐水中即为实验液体。用气泡型表面张力计测定各实验液体的表面张力。将PS缺如的未成熟胎兔随机分为4组:PS、SL、RS-3和对照组。分别向PS、SL和RS-3组气道内注入PS、SL、RS-3液;对照组未注入任何物质。然后进行人工通气,通气后5、10、15、20min测定各组潮气量。结果 PS的最小表面张力(γmin)为(0.9±0.3)mN/m,SL的γmin为(22.6±1.3)mN/m,明显高于PS(P<0.01);随SP-C浓度的增加γmin逐渐降低,RS-3的γmin降至(0.7±0.1)mN/m(与PS相比,P>0.05)。通气20min时,PS组、RS-3动物的潮气量分别达到(25±7)ml/kg、(25±4)ml/kg,明显高于对照组和SL组(P<0.01)。结论 不含SP-C的合成脂质表面活性低,加入SP-C后构成的重组PS表面活性明显增强。     

外源性肺表面活性物质对呼吸机相关性肺损伤大鼠炎性反应的影响

目的 探讨外源性肺表面活性物质(PS)对呼吸机相关性肺损伤(VILI)大鼠炎性反应的影响.方法 成年雄性Wistar大鼠28只,体重310-388 g,采用随机数宁表法,将大鼠随机分为4组(n=7),对照组(C组)、VILI组、PS组和空气对照组(A组).采用高气道压机械通气(气道峰压40cmH2O,通气频率20次/min,PEEP 0)20 rin制备VILI模型.C组麻醉后即经股动脉放血处死.VILI 组于模型制备成功后放血处死.PS组和A组造模后采用自制吸痰管吸除气道内水肿液后经气道分别注入PS 100 mg/kg(50 mg/ml)和等容量空气,行机械通气(VT10 ml/kg,通气频率45次/min,PEEP 7.5cm H2O)120 min后放血处死.采集股动脉血样及气道内水肿掖,采用ELISA法测定血浆IL-6、IL-10、巨噬细胞炎性蛋白-2(MIP-2)和TNF-α浓度,采用Bradford蛋白浓度测定法测定气道内水肿液蛋白浓度.光镜下观察肺组织病理学及中性粒细胞数目.结果 4组血浆TNF-α浓度比较差异无统计学意义(P ＞0.05).与C组比较,VILI组血浆MIP-2、IL-10和IL-6浓度及中性粒细胞计数升高(P＜0.05),气道水肿液量和水肿液蛋白浓度比较差异无统计学意义(P＞0.05).与A组比较,PS组中性粒细胞计数减少(P＜0.05),气道水肿液量和水肿液蛋白浓度比较差异无统计学意义(P＞0.05),血浆MIP-2、IL-10和IL-6浓度差异无统计学意义(P＞0.05).VILI组、A组和PS组肺组织炎性损伤明显.结论 外源性PS治疗VILI大鼠可减少肺组织中性粒细胞募集,但不能抑制炎性细胞因子的释放.     

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.