左旋精氨酸对大鼠心脏移植物血管病变的抑制作用

目的　研究左旋精氨酸对大鼠心脏移植物血管病变的抑制作用及其机理。方法　采用大鼠异位心脏移植模型。对照组 :移植后不用左旋精氨酸 ;实验组 :移植后按 80 0mg·kg-1·d-1将左旋精氨酸加入饮水中。于移植后 2个月和 3个月检测各组的心脏移植物 ,血管病变评分和血浆一氧化氮含量。结果　移植后 2个月 ,实验组的移植物存活率为 90 .5 % ,显著高于对照组的 6 1.5 % (P <0 .0 5 )。移植后 2个月和 3个月 ,实验组血浆一氧化氮含量均显著高于对照组 ,分别为 ( 10 5 .37± 10 .6 6 ) μmol/Lvs( 6 8.5 4± 6 .83) μmol/L(P <0 .0 5 ) ,和 ( 10 4.5 3± 12 .31) μmol/Lvs ( 6 6 .32± 10 .5 4) μmol/L(P <0 .0 5 ) ;而对照组心脏移植物血管病变评分显著高于实验组 ,分别为 2 .4± 0 .7vs 1.1± 0 .6 (P <0 .0 5 ) ,和 3.0±0 .8vs 1.6± 0 .9(P <0 .0 5 )。实验组心脏移植物的冠状动脉内膜病变轻微 ,内皮和内弹力层基本保持完整 ,平滑肌细胞增殖不明显。结论　补充左旋精氨酸可改善心脏移植物血管病变 ,其机理与一氧化氮合成增加有关。一氧化氮具有保持内皮功能 ,抑制平滑肌细胞增殖的作用。     

缺血预处理对大鼠移植肝脏保存再灌注损伤的保护及机制探讨

目的探讨缺血预处理 (ischemicpreconditioning ,IP)对大鼠移植肝脏保存再灌注损伤的保护作用及机理。方法采用SD大鼠原位肝移植动物模型 ,12 8只大鼠随机分成A(对照组 )、B(IP组 )、C(腺苷 ,Ado组 )、D(NO合成抑制剂 ,NAME组 )组 ,每组 32只。其中各组的半数用于观察存活率 ,另一半用于移植肝脏再灌注 2h后取血及肝脏检测。结果IP组和Ado组的 1周存活率、血清NO水平及肝组织腺苷含量分别为 88% (7/ 8)和 88% (7/ 8) ,(33 0± 6 1) μmol/l和 (2 9 1± 6 5 ) μmol/l,(7 2± 1 8) μmol/g和 (5 7± 1 3) μmol/g ,均高于对照组的 38% (3/ 8) ,(15 4± 3 0 )mol/L和 (3 6 9±0 5 4 ) μmol/g (P <0 0 5 ) ,血清ALT及TNF含量分别为 (2 87± 82 )IU/L和 (35 7± 93)IU/L ,(1 15± 0 2 3)ng/ml和 (1 14± 0 2 7)ng/ml,均低于对照组的 (5 88± 5 8)IU/L及 (1 5 9± 0 35 )ng/ml(P <0 0 5 ) ,组织的病理学改变也轻于对照组 ;NAME组的 1周存活率、血清NO及ALT含量等分别为 2 5 % (2 / 8)、(13 74± 3 11) μmol/l及 (6 34± 6 5 )IU/L ,与对照组相近 (P >0 0 5 ) ,而肝组织腺苷含量为 (5 5 6± 1 19)μmol/g ,与对照组差异有显著意义 (P <0 0 5 )。 结论IP对大鼠移植肝脏的保存再灌注损伤具有保护     

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目的　探讨失血性低血容量休克病人血浆一氧化氮 (NO)浓度与预后的关系。方法　 2 0 0 1年 7月至2 0 0 2年 1月 ,应用比色法测定 2 9例失血性低血容量休克病人血浆NO浓度 ,与 2 0例择期手术病人进行对照 ,观察NO与多器官功能障碍综合征 (MODS)的关系。结果　休克组血浆NO浓度 ( 74 2± 46 9) μmol/L ,较对照组( 5 0 5± 2 3 3 ) μmol/L明显升高 (P <0 0 5 )。休克组发生MODS病人血浆NO浓度 ( 90 4± 5 3 5 ) μmol/L ,较未发生MODS者血浆NO浓度 ( 5 4 2± 2 7 9) μmol/L明显升高 (P <0 0 5 )。 结论　失血性低血容量休克NO产生过多可能参与MODS的发生     

吸入性一氧化氮在ETCPC术后早期的临床应用效果

目的　评价吸入性一氧化氮 (INO)在心外管道全腔静脉肺动脉连接 (ETCPC)术后早期疗效。方法　ETCPC术后早期吸入NO者为试验组 ,未吸入NO者为对照组 ,各 16例。记录两组吸入及停用INO前后心排出量、肺血管阻力 (PVR)、呼吸指数、肺动脉 -左房压力阶差 (PLG)。记录两组呼吸机辅助时间、ICU滞留时间、胸腔引流管留置时间及住院时间。结果　试验组NO吸入后呼吸指数从 2 . 6 1±0 .32下降至 1. 4 1± 0 .2 1,t=2 . 35 ,P <0 .0 5 ;PLG(mmHg)从 11± 2降至 7± 3,t =2 .76 ,P <0 . 0 1;氧合指数从 16. 3± 18升高至 191± 2 1,t=2 . 74 ,P <0 .0 1;心指数 (CI ,L·min-1·m-2 )从 2 . 84± 0 . 2 3增加至 3 .12±0 . 2 0 ,t=2 . 2 4 ,P <0 .0 5 ;肺血管阻力从 4 . 2 3± 0 .5 3下降至 3 .77± 1 .4 2 ,t =2 . 2 8,P <0 . 0 5 ;中心静脉压(CVP ,mmHg)从 17 .0± 1 9下降至 15 .0± 1. 2 ,下降约 11 .8% ;INO停用前后各项上述指标未见明显差异。与对照组相比较 ,呼吸机辅助时间从 (76± 2 5 )h缩短为 (5. 6± 19)h ,t=2 . 2 8,P <0 . 0 5 ;重症监护时间从 (6± 2 )d缩短至 (4± 2 )d ,t=2 . 33,P <0. 0 5 ;胸腔引流管留置时间及住院时间差异无统计学意义。结论　INO对ETCPC术后远期疗效无明显影响 ,但     

诱生型一氧化氮合酶选择性抑制剂对急性胰腺炎大鼠胰腺组织的影响

目的　探讨急性胰腺炎大鼠胰腺组织中诱生型一氧化氮合酶 (iNOS)选择性抑制剂(氨基胍 )对胰腺组织的影响。方法　分别测定各组胰腺组织中原生型一氧化氮合酶 (cNOS)和iN OS活性、一氧化氮 (NO)含量 ;观察各组胰腺组织病理变化 ,并对胰腺组织损伤进行评分。结果　与胰腺炎组比较 ,单用氨基胍可明显降低NO含量 [( 2 2 .4± 0 .3) μmol/g ,P <0 .0 5 ] ,而胰腺病理评分无降低 ( 8.8± 0 .6 ,P >0 .0 5 ) ,联合应用L 精氨酸不但可明显降低NO含量 [( 2 5 .6± 0 .4) μmol/g ,P <0 .0 5 ] ,并且胰腺病理评分明显降低 ( 6 .3± 1.4,P <0 .0 5 )。 结论　联合应用选择性iNOS抑制剂和NO供体 ,可降低胰腺组织中NO含量 ,并能改善胰腺组织病理损伤。     

肿瘤坏死因子α介导骨骼肌缺血-再灌注损伤的实验研究

目的研究肿瘤坏死因子α(TNF α)介导骨骼肌缺血 再灌注损伤的作用机制。方法2 4只健康雄性SD大鼠 (2 5 0～ 30 0g)随机分成 3组。对照组 :仅行麻醉及颈外静脉插管术 ;损伤组 :左后肢缺血 4h ,再灌注 4h ;治疗组 :缺血 4h ,再灌注 4h ,再灌注即刻经静脉导管给与抗TNF α单克隆抗体。结果损伤组较对照组单核细胞TNF αmRNA转录增加 ,血浆丙二醛 (MDA) (9 9± 1 8)比(5 5± 0 4 )、肌酸激酶 (CK) (12 2± 2 4 )比 (49± 11)、一氧化氮 (NO) (2 70± 98)比 (12 8± 4 6 )、组织过氧化物酶 (MPO) (骨骼肌 4 2 7± 0 5 3)比 (1 2 8± 0 19,肺 2 6 1± 0 12 )比 (0 5 7± 0 0 2 )显著升高 (P <0 0 1) ,骨骼肌和肺组织超微结构发生病理改变。治疗组较损伤组MDA(6 2± 1 2 )比 (9 9± 1 8)、CK(5 8±12 )比 (12 2± 2 4 )、NO(15 4± 5 5 )比 (2 70± 98)、MPO(骨骼肌 2 13± 0 2 1)比 (4 2 7± 0 5 3肺 0 95± 0 0 1)比(2 6 1± 0 12 )水平明显降低 (P <0 0 5 ) ,骨骼肌和肺组织病理损伤减轻。结论骨骼肌缺血 再灌注激发TNF α的生成 ,在介导骨骼肌和肺的损伤中起重要作用     

一氧化氮在急性坏死性胰腺炎大鼠肺损伤中的作用

目的　探讨一氧化氮 (NO)在急性坏死性胰腺炎 (ANP)肺损伤中的作用。　方法12 0只成年SD大鼠随机分为正常对照组、ANP组、精氨酸 (L Arg)组、N 硝基 L 精氨酸甲酯 (L NAME)组、混合预处理组 ,每组 2 4只。逆行性胰胆管注射 3%牛磺酸钠建立ANP大鼠模型。经支气管肺泡灌洗获取肺泡巨噬细胞 (AM) ,检测支气管肺泡灌洗液 (BALF)中蛋白含量、肺组织髓过氧化物酶 (MPO)水平、AM分泌肿瘤坏死因子α(TNFα) ,NO水平及TNFαmRNA、诱导型一氧化氮合酶(iNOS)mRNA表达情况。　结果　ANP大鼠肺损伤随着病情进展而逐渐加重 ;肺组织MPO及BALF蛋白含量逐渐升高 ,12h达最高值 ,分别为 (10 8± 0 6 )U/g和 (2 0 11 0± 10 5 5 ) μg/ml;AM分泌TNFα ,NO水平逐渐升高 ,至 6h达到高峰 ,分别为 (16 2 4 2± 14 9 2 ) pg/ml和 (88 8± 6 5 )μmol/L ,12h又回落。AMTNFαmRNA、iNOSmRNA的表达情况与TNFα,NO的变化趋势相似。L Arg、L NAME、混合预处理三组各指标变化趋势与ANP组相似 ,各组与正常对照组相比 ,均有显著性差异 (P <0 0 5 )。L Arg、L NAME组与ANP组相比 ,L Arg组各指标均升高 ,L NAME组各指标均降低 ,差异亦有显著性 (P <0 0 5 )。　结论　由iNOS介导产生的NO的过量生成促进了ANP所致的肺损伤。加入外源性     

吸入一氧化氮在双向腔肺动脉吻合术后的应用

目的　评价吸入一氧化氮 (NO)对双向腔肺动脉吻合 (BCPS)术后肺血流灌注不足病儿的作用。方法　 2 0例病儿吸入NO 2 5～ 15 0百万分之一体积 (ppm) ,定时记录各项血流动力学和呼吸功能指标 ,定期监测二氧化氮 (NO2 )、高铁血红蛋白 (MetHb)含量。结果　吸入NO后 ,中心静脉压从( 2 1 4±4 8)mmHg( 1mmHg =0 133kPa)降至 ( 15 3± 5 9)mmHg,跨肺压从 ( 16 2± 5 3)mmHg降至( 8 8± 4 2 )mmHg ,肺泡 -动脉氧分压差从 ( 391 7± 15 1 9)mmHg降至 ( 2 94 0± 312 5 )mmHg ,呼吸指数从 11 3± 5 3降至 6 8± 3 0 (P <0 0 1) ;动脉血氧饱和度从 0 78± 0 14升至 0 84± 0 9,动脉血氧分压与吸入氧浓度之比从 ( 6 7 0± 30 1)mmHg升至 ( 88 8± 2 6 1)mmHg(P <0 0 1)。吸入NO期间 ,NO2 和MetHb含量分别为 ( 0 1± 0 2 )ppm和 ( 1 2± 0 4) %,均在安全范围内。结论　一氧化氮作为一种选择性肺血管扩张剂 ,用于双向腔肺动脉吻合术后肺血管阻力暂时性增高的病儿 ,可改善其肺血流灌注和氧合功能 ,无明显毒副作用。     

内皮素-1 mRNA在肝肺综合征大鼠肺组织中表达的研究

目的　研究内皮素 1(ET 1)及其mRNA在肝肺综合征 (HPS)大鼠肺组织中的表达。方法　 3 2只雄性SD大鼠随机分 4组 :肝前型门静脉高压症组 (PHPH)、肝内型门静脉高压症组(IHPH)、门腔端侧分流组 (PCS)和手术对照组 (SO) ,每组 8只。各组均行动脉血气分析 ;应用硝酸还原酶法和放射免疫法测定肺组织中NO2 -/NO3-及ET 1含量 ;应用原位杂交和图像分析 ,检测肺泡毛细血管内皮细胞、肺泡动脉内皮细胞和支气管上皮细胞中ET 1mRNA的表达强度。　结果　 ( 1)动脉血气分析 :动脉氧分压IHPH组大鼠 [( 73 85± 6 5 1)mmHg]较PHPH组 [( 97 3 9± 1 3 3 )mmHg]、PCS组 [( 95 2 3± 2 2 2 )mmHg]和SO组 [( 99 0 5± 0 75 )mmHg]显著下降 (P <0 0 5 ) ;肺泡 动脉氧压力梯度 :IHPH组大鼠 [( 3 4 5 3± 2 3 2 )mmHg]较PHPH组 [( 4 98± 1 69)mmHg]、PCS组 [( 6 5 1± 2 0 4 )mmHg]和SO组 [( 3 2 3± 0 81)mmHg]显著增大 (P <0 0 5 ) ,并伴轻度呼吸性碱中毒。 ( 2 )肺组织中NO2 -/NO3-含量 ( μmol/g蛋白 ) :IHPH组大鼠 ( 19 78± 5 3 3 ) μmol/g显著高于PHPH组 ( 13 2 1± 3 99)μmol/g、PCS组 ( 13 89± 3 16) μmol/g和SO组大鼠 ( 8 71± 1 68) μmol/g。肺组织中ET 1含量 (pg/g) :IHPH组大鼠 ( 195 1     

一氧化氮在犬离体胰腺低温灌注与保存中的作用

目的探讨一氧化氮(NO)对犬胰腺低温灌注及保存中缺血再灌注损伤的影响。方法在EC(EuroCollin)液中分别加用L精氨酸(LArg,200mg/kg体重)、N硝基L精氨酸甲酯(LNAME,10mg/kg体重)和生理盐水,分别对犬离体胰腺节段进行低温灌注保存(灌注量为30～50ml,温度为0～4℃,时间为24h),应用犬胰节段移植模型,测定移植后犬血清中脂肪酶、淀粉酶含量,测定移植胰腺组织中髓过氧化酶(MPO)活性、一氧化氮(NO)含量、一氧化氮合酶(NOS)及诱导型一氧化氮合酶(iNOS)mRNA的表达情况。并进行组织学观察。结果血清脂肪酶,LArg处理组<对照组对照组(0.31±0.06)μmol/L>LNAME处理组(0.17±0.04)μmol/L;NOS活性:LArg处理组(3.13±0.19)U/ml>对照组(2.37±0.20)U/ml>LNAME处理组(1.68±0.20)U/ml;iNOSmRNA的表达:LArg处理组(0.89±0.22)μmol/L>对照组(0.63±0.18)μmol/L>LNAME处理组(0.49±0.20)μmol/L,差异有统计学意义(P<0.05);LArg处理组胰小叶间质水肿和胰小叶内中性粒细胞浸润较轻。结论NO对犬胰腺低温灌注及保存中缺血再灌注损伤具有保护作用。     

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 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.     

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.     

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.     

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.     

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.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.