异氟烷预处理对离体大鼠浅低温缺血再灌注心肌线粒体耐受性的影响

目的探讨异氟烷预处理能否诱导浅低温缺血再灌注心肌线粒体耐受。方法采用SD大鼠离体心脏Lange-ndroff灌注模型。建立离体大鼠31℃低温全心缺血55min,常温再灌注60min损伤模型。SD离体大鼠心脏随机分为4组(n=10/组):对照组(CON)用K-H液灌注50min后31℃低温缺血55min,常温复灌60min。异氟烷预处理组(ISC1、ISC2、ISC3),分别在缺血前给予0.5%、1.0%、2.0%的异氟烷预充饱和的K-H液灌注15min及洗脱15min。再灌注末,立刻分离心肌线粒体。观察指标有:LVEDP、LVSP、dp/dtmin、dp/dtmax、HR、梗死面积、线粒体和胞浆的细胞色素C。结果同对照组相比,复灌30min及60min时,各组LVSP、dp/dtmin、dp/dtmax、HR均无显著差异,仅ISC3组的LVDEP显著低于CON组(P<0·05)。复灌60min后ISC2组和ISC3组梗死面积显著低于CON组和ISC1组(P<0·05)。异氟烷预处理使浅低温缺血再灌注后心肌线粒体细胞色素C的释放减少。与CON组相比ISC3组胞浆细胞色素C的量明显减少(P<0·05),同时伴随线粒体的细胞色素C显著增加(P<0·05),ISC2组线粒体细胞色素C的量也显著多于CON组(P<0·05)。结论异氟烷预处理能通过诱导线粒体耐受(以线粒体细胞色素C丢失为线粒体功能障碍指标)抗心肌浅低温缺血再灌注损伤。     

高糖灌注对糖尿病大鼠离体缺血再灌注心脏心律失常及肌酸激酶的影响

目的 探讨高糖灌注对3～4周糖尿病大鼠离体缺血再灌注心脏心律失常及肌酸激酶的影响。方法 链脲佐菌素诱导糖尿病大鼠14只,3～4周时随机分为二组:KHB灌注组(DM KHB组)和高葡萄糖灌注组(DM GLU组),每组7只;正常对照组(n=10,C组),仅注射枸橼酸缓冲液。戊巴比妥钠麻醉后取出心脏置于Langendorff装置上,采用主动脉逆灌法,平衡灌注20min,停灌全心缺血30min后复灌40min,造成心肌缺血再灌注模型。采用MPA 2000多道生理记录仪监测心肌表面心电活动,观察心动过速(VT)、心室颤动(VF)发生率和持续时间,并进行心律失常评分,测定再灌注期冠脉流出液中肌酸激酶(CK)活性。结果 DM KHB、DM GLU组VT、VF、心律失常评分及冠脉流出液中CK活性低于C组(P<0.05或0.01);与DM KHB组比较,DM GLU组心律失常评分差异无显著性(P>0.05)、CK活性升高(P<0.05)。结论 3～4周糖尿病心脏缺血耐受性增强,再灌注心律失常减轻。高糖灌注降低糖尿病心脏对缺血的耐受性,但对再灌注心律失常无不利影响。     

丙泊酚对离体兔心脏再灌注性心律失常的保护作用及机制研究

目的　在离体兔心脏缺血再灌注模型研究丙泊酚对再灌注性心律失常的保护效应及与氧自由基的关系。方法　 2 4只心脏随机分为缺血再灌 (A)、丙泊酚 10 μmol/L(B)、丙泊酚 2 5 μmol/L(C)和空白对照 (D)四组。A、B和C组心脏行停灌全心缺血 3 0分钟后 ,再灌注 60分钟。结果　缺血前给予丙泊酚 2 5 μmol/L能显著降低复灌时室性心律失常的发生率 (P <0 0 1)和持续时间 ,且使ST段抬高平均值 (MST)和抬高≥ 2mv的点数 (NST)分别减少 62 %和 4 7% (P <0 0 5 )。丙泊酚10 μmol/L并不增强其抗心律失常作用。高浓度丙泊酚显著增强心肌超氧化物歧化酶 (SOD)活力 ,降低缺血后心肌丙二醛 (MDA)及磷酸肌酸 (CK)含量 (P <0 0 5 ) ,但低浓度丙泊酚无上述作用。结论　心肌缺血前给予 2 5 μmol/L丙泊酚能显著减少复灌性心律失常的发生 ,同时减少心肌酶释放 ,其作用可能与其降低心肌氧自由基造成的心肌损伤有关。     

褪黑素对鼠心肌缺血再灌注损伤的保护作用

目的探讨不同浓度褪黑素预处理对成年大鼠心肌缺血再灌注损伤的影响。方法32只成年SD大鼠(350～400g)随机分为4组(n=8),利用Langendorff模型灌注其离体心脏,对照组平衡30min后缺血再灌注,实验组用不同浓度褪黑素预处理液灌注30min后缺血再灌注。各组均为常温(37℃)缺血25min,复灌60min。观察各组冠脉流出液中心肌肌钙蛋白(cTnI)、心肌超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量及心肌细胞超微结构的变化。结果复灌后,cTnI含量(μg/L)Ⅰ组为2.69±0.18,Ⅱ组为1.75±0.13,Ⅲ组为1.06±0.08,Ⅳ组为0.45±0.11;心肌组织SOD(nu/mg蛋白)和MDA(nmol/mg蛋白)含量Ⅰ组为207.4±7.9和1.815±0.018,Ⅱ组为238.3±2.9和1.472±0.518,Ⅲ组为268.3±5.7和1.122±0.263,Ⅳ组为315.6±9.0和0.961±0.223。心肌细胞电镜观察显示预处理组心肌细胞损伤轻于对照组。结论褪黑素预处理对成年大鼠缺血再灌注心肌有保护作用。     

异丙酚、芬太尼对离体心肌缺血再灌注损伤的影响

目的 评价异丙酚、芬太尼对离体心肌缺血再灌注损伤的作用。方法 采用离体鼠Langendroff脏模型,SD大鼠 32只,取心脏用 K-H液恒温恒压主动脉逆灌、平衡 15min,随机分为 4组:（A）脂肪乳剂对照组;（B）5μg·ml-1异丙酚组;（C）10ng·ml-1芬太尼组;（D）5μg·ml-1异丙酚加10ng·ml-1芬太尼组。用含相应药液的 K-H液灌注 10min,常温全心停灌30min,然后用含相应药液的K-H液恢复灌注30min,记录各组用药前、停灌前1min、再灌30min时心脏机械功能变化、冠脉流量以及测定再灌注30min冠脉流出液里乳酸脱氢酶（LDH）活性。结果 再灌30min时B、C、D组心功能的恢复明显好于A组,D组明显好于B、C组。LDH活性B、C、D组明显低于A组,D组明显低于B、C组。结论5μg·ml-1异丙酚、10ng·ml-1芬太尼能抑制离体心肌缺血再灌注损伤,两者复合应用其作用更强。     

右美托咪啶后处理对大鼠离体心脏缺血再灌注时线粒体损伤的影响

目的 探讨右美托咪啶后处理对大鼠离体心脏缺血再灌注时线粒体损伤的影响.方法 健康雌性Wistar大鼠,体重220～250 g,成功制备Langendorff离体灌注模型的40个心脏随机分为5组(n=8):缺血再灌注组(A组)、右美托咪啶10 nmol/L组(B组)、右美托咪啶100 nmol/L组(C组)、线粒体通透性转换孔开放剂苍术苷组(D组)及右美托咪啶联合苍术苷组(E组).离体心脏经K-H液平衡灌注20 min后,采用全心停灌40 min再灌注60 min的方法制备离体心脏缺血再灌注模型.于再灌注即刻B组、C组、D组和E组分别灌注含10 nmol/L右美托咪啶、100 nmol/L右美托咪啶、20μmol/L苍术苷、100 nmol/L右美托咪啶和20 μmol/L苍术苷的K-H液10 min.再灌注结束即刻取心尖组织,分离线粒体,测定SOD、Na+ -K+ -ATP酶、Ca2+-ATP酶活性和MDA和Ca2+含量.结果 与A组比较,B组和C组线粒体SOD、Na+ -K+ -ATP酶和Ca2+ -ATP酶活性升高,MDA和Ca2+含量降低(P＜0.05),D组和E组上述指标比较差异无统计学意义(P＞0.05);与C组比较,D组和E组线粒体SOD、Na+-K+-ATP酶和Ca2+ -ATP酶活性降低,MDA和Ca2+含量升高(P＜0.05),B组上述指标比较差异无统计学意义(P＞0.05).结论 右美托咪啶后处理可减轻大鼠离体心脏缺血再灌注时的线粒体损伤,其机制可能与抑制线粒体通透性转换孔开放有关.     

单纯缺血预处理对兔未成熟心脏不足以提供保护作用

目的探讨单纯缺血预处理(IPC)对兔未成熟心脏缺血再灌注损伤的影响.方法利用Langendorff模型灌注幼兔(14-21d)离体心脏,5min缺血、10min再灌的IPC处理后,观察其在生理体温(39℃)下接受30min缺血、40min复灌的血液动力学、冠脉流出液心肌酶及心肌能量的变化.结果复灌后IPC组与对照组在心率(HR)、冠脉流出量(CF)、左室发展压(LVDP)、左室最大上升和下降速率(±dp/dt)恢复率及室性心律失常发生率无明显差别,肌酸磷酸激酶同工酶(CK-MB)漏出量有增多趋势.而IPC组在全心停灌后心脏缺血跳动时间明显延长(P＜0.01),再灌注末心肌ATP含量显著减少(P＜0.001).结论单纯缺血预处理不能保护未成熟心脏免受心肌缺血再灌注损伤,反而可导致心肌细胞的损伤;其原因可能与全心缺血后,心脏不能很快停跳而导致能量消耗过多有关.     

再灌注早期应用雌二醇对缺血鼠心肌的保护作用

目的　探讨再灌注早期应用 17β 雌二醇 (17β estradiol,E2 )对心肌缺血再灌注损伤 (MIRI)的影响。方法　采用Langendorff离体鼠心脏灌注模型 ,将 30只雌性卵巢切除 (OVX)大鼠随机均分为 3组。缺血再灌注组 (I R组 )用K H液预灌注 15min ,常温停灌 30min ,恢复K H液再灌注 30min。 0 1%二甲基亚砜组 (D组 )和 5 μmol LE2 组 (E组 )从再灌注第 6min起改用含相应药液的K H液灌注 2 5min ,余同I R组。记录各组心功能及冠脉流量 (CF) ,测量冠脉流出液中乳酸脱氢酶 (LDH)、肌酸磷酸激酶 (CPK)、心肌丙二醛 (MDA)含量及心肌超氧化物歧化酶 (SOD)活性的变化。结果　再灌 30min时 ,E组CF比I R、D组明显增加 (P <0 0 1) ;I R、D、E组心功能均降低 ,但I R和D组较E组更为显著 (P <0 0 1) ;E组SOD活性明显高于I R和D组 (P <0 0 1)而MDA、CPK和LDH的含量明显低于I R和D组 (P <0 0 1) ;I R组和D组之间未显示出统计学差异。结论　E2 可通过其抗氧化作用 ,防止MIRI。     

瑞芬太尼预处理对大鼠心肌缺血再灌注损伤的影响

目的观察瑞芬太尼预处理对大鼠心肌缺血再灌损伤的影响。方法建立50只大鼠心肌缺血再灌注损伤模型。随机分为对照组(CON组)、缺血预处理(IPC)组和瑞芬太尼预处理(RPC) 组,RPC组根据瑞芬太尼不同给药剂量又分为RPC1、RPC2、RPC3、RPC4、RPC5组,分别以0.2、0.6、2、6 和20μg·kg-1·min-1速率静脉泵注5 min,停止5 min,重复进行3次。于缺血前30 min、缺血30 min、再灌注120 min时记录心电图、收缩压、平均动脉压(MAP)、HR,计算收缩压与HR乘积(RPP)。再灌注120min时取出大鼠心脏,称心脏湿重,并制作心肌病理切片,计算左心室(LV)、右心室(RV)、缺血危险区(AAR)和梗死区(IS)的面积及体积,计算LV与RV体积之和、IS面积与AAR面积之比(IS/AAR)。结果与CON组比较,RPC2、RPC3、RPC4和RPC5组缺血30 min时MAP降低(P<0.05)。IPC、RPC1、RPC2、RPC3、RPC4、RPC5组IS和IS/AAR降低(P<0.05或0.01),心脏湿重、LV与RV体积之和、AAR 体积差异无统计学意义(P>0.05)。各组HR、RPP比较差异无统计学意义(P>0.05)。瑞芬太尼剂量-效应关系Sigmoidal方程为:Y=15.18+17.76/[1+10(-2.75-X)],ED50为2.689μg·kg-1·min-1。结论瑞芬太尼可模拟心脏缺血预处理作用,对心肌缺血再灌注损伤具有保护作用。     

cAMP-PKA信号转导通路在缺血预处理减轻大鼠离体心脏缺血再灌注损伤中的作用

目的 探讨cAMP-PKA信号转导通路在缺血预处理减轻大鼠离体心脏缺血再灌注损伤中的作用.方法 成年SD大鼠50只,体重300-350g,采用Langendorff装置建立大鼠离体心脏缺血再灌注模型后随机分为5组(n=10):缺血再灌注组(IR组)、缺血预处理组(IPC组)、H89组、脯氨酸二硫氨基甲酸组(PDTC组)和双丁酰环磷酸腺苷组(db-cAMP组).K-H液平衡灌注10 min后,R组K-H液继续灌注30 min后停灌1 h,再灌注30 min;IPC组停灌5 min,再灌注5 min.反复3次,停灌1 h再灌注30 min;PDTC和H89组停灌5 min,分别用含有PDTC 100μmol/L和含有H89 10 μmol/L的K-H液再灌注5 min,反复3次,余同IPC组;db-cAMP组用含db-cAMP 200 μmollL的K-H液灌注30 min,停灌1 h再灌注30 min.于平衡灌注10 min、再灌注10、20和30 min时记录左心室压力最大变化速率(±dp/dtmax)和左心室发展压(LVDP).于平衡灌注10 min和再灌注30 min时记录冠脉流出量(CF);测定冠脉流出液中乳酸脱氢酶(LDH)和磷酸肌酸激酶(CK)活性.于再灌注30 min时取心肌组织,采用EMSA法检测NF-κB-DNA结合活性,采用RT-PCR法检测TNF-α mRNA表达,采用Western blot法检测磷酸化环腺苷酸反应元件结合蛋白(p-CREB)(Serl33)表达.结果 与IR组比较,IPC组和db-cAMP组NF-κB-DNA结合活性和TNF-α-mRNA表达降低,±dp/dt和CF升高,CK和LDH活性降低,WC组、PDTC组和db-cAMP组p-CREB(Ser133)表达升高(P<0.05或0.01);与IPC组比较,H89组和PDTC组NF-κB-DNA结合活性和TNF-αmRNA表达升高,±dp/dt、LVDP和CF降低,CK和LDH活性升高.H89组p-CREB(Serl33)表达降低(P<0.05或0.01).结论 缺血预处理通过激活cAMP-PKA信号转导通路抑制NF-κB-DNA结合活性,减少炎性因子的基因转录.从而减轻大鼠离体心脏缺血再灌注损伤.     

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 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.     

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.     

Immunomodulation in Transplantation with Photopheresis

Abstract: Photopheresis is a technique in which peripheral blood mononuclear cells, in the presence of a photoacti-vatable compound, are exposed extracorporeally to ultraviolet A light and reinfused, inducing a host autoregula-tory immune response. Experimental work and ongoing clinical studies are helping to define the role of this novel, safe, and non-toxic immunomodulating technology in the field of transplantation.