缺血后处理对大鼠离体心脏缺血再灌注损伤的作用

目的探讨缺血后处理对大鼠离体心脏缺血再灌注损伤的作用。方法24只Wistar大鼠,随机分为3组(n=8):正常对照组(C组)、缺血再灌注组(I/R组)、缺血后处理组(IPC组)。采用大鼠离体心脏Langendorff灌流模型,C组用K-H液灌注160min;I/R组全心缺血40 min,再灌注120 min; IPC组全心缺血40 min后,再灌注10 s,缺血10 s,反复6次,然后持续再灌注118 min。测定再灌注15、30、120 min时冠脉流量(CF)及冠脉流出液心肌肌钙蛋白I(cTnI)浓度,再灌注120 min时,取心肌组织,测定丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性,电镜下观察心肌细胞超微结构。结果缺血再灌注可导致CF降低,冠脉流出液cTnI浓度升高,心肌SOD活性下降,MDA含量升高,心肌细胞超微结构产生病理学改变,缺血后处理可减弱上述改变。结论缺血后处理减轻脂质过氧化反应,对大鼠离体缺血再灌注心脏产生保护作用。     

异丙酚对大鼠离体心脏缺血再灌注时NF-κB及iNOS的影响

目的 探讨异丙酚对大鼠离体心脏缺血再灌注时核因子κB(NF-κB)及诱导型一氧化氮合酶(iNOS)的影响.方法 成年SD大鼠24只,体重200～300 g,雌雄不拘,随机分为3组(n=8):对照组(C组)、缺血再灌注组(I/R组)和异丙酚组(P组).建立Langendorff离体心脏灌注模型,K-H液平衡20 min后开始实验.C组灌注K-H液110 min;I/R组灌注K-H液20 min后,全心停灌30 min,再灌注60 min;P组用含50 μmol/L异丙酚的K-H液灌注20 min,全心停灌30 min,再用含50 μmol/L异丙酚的K-H液灌注60 min.于平衡末、再灌注10 min和60 min时测定冠状动脉流出液心肌肌钙蛋白(cTnI)浓度;于再灌注60 min时测定心肌SOD活性、MDA含量、iNOS活性及NF-κB、IκB的表达水平.结果 与C组比较,I/R组再灌注期间冠状动脉流出液cTnI浓度升高,P组再灌注期间60 min时升高(P＜0.05或0.01),I/R组心肌SOD活性降低,MDA含量增多,iNOS活性升高(P＜0.01),I/R组和P组心肌NF-κB表达升高,kB表达降低(P＜0.05或0.01).与I/R组比较,P组再灌注期间冠状动脉流出液cTnI浓度、心肌MDA含量、NF-κB表达、iNOS活性均降低,心肌SOD活性和IκB表达升高(P＜0.01).结论 异丙酚可抑制心肌NF-κB的激活,降低iNOS的活性,从而减轻大鼠离体心脏缺血再灌注损伤.     

钙网蛋白在不同预处理心肌细胞缺血再灌注的保护作用

目的 观察3种不同预处理对在体缺血再灌注心肌的保护作用,探讨钙网蛋白(CRT)在预处理心肌细胞缺血再灌注损伤的作用.方法 将30只成年SD大鼠随机分成5组(n=6),分别为缺血再灌注组、缺血预处理组、腺苷预处理组、远程预处理组和假手术组.建立大鼠在体缺血冉灌注损伤模型,观察各组缺血再灌注前后心功能变化,并检测再灌注末血清肌钙蛋白T(cTnT)、丙二醛(MDA)、超氧化物歧化酶(SOD)的变化以及心肌组织CRT的表达.结果 缺血预处理组、远程预处理组与缺血再灌注组比较(±dp/dt max)有明显提高(P<0.05).缺血预处理组、腺苷预处理组、远程预处理组cTnT、MDA值均低于缺血再灌注组,SOD值高于缺血再灌注组(P<0.05);腺苷预处理组SOD值高于缺血预处理组和远程预处理组,cTnT值则低于后2组(P<0.05);缺血预处理组、腺苷预处理组、远程组与缺血再灌注组比较,CRT表达灰度值均显著降低(P<0.05).结论 腺苷预处理、远程预处理均可以模拟缺血预处理的心肌保护作用;预处理可能通过下调钙网蛋白高表达减轻在体大鼠心肌细胞缺血再灌注损伤.     

大鼠急性肝缺血-再灌注时心肌细胞氧化损伤及瑞芬太尼的干预作用

目的 观察大鼠急性肝缺血-再灌注时心肌细胞氧化损伤以及瑞芬太尼预处理对氧化损伤的干预作用.方法 建立大鼠肝缺血-再灌注损伤模型.将72只Wistar大鼠随机分为瑞芬太尼预处理组(R组,n=24)、缺血-再灌注组(IR组,n=24)、假手术组(Sham组,n=24).于再灌注30min、1、2、3 h处死大鼠.R组缺血前以1μg·kg-1·min-1微泵输注瑞芬太尼30 min进行预处理.分别检测各组大鼠心肌组织丙二醛(MDA)含量、超氧化物歧化酶(SOD)活力及谷胱甘肽过氧化氧酶(GSH-Px)活力变化.结果 与Sham组比较,R组和IR组再灌注1、2、3 h时心肌组织MDA含量明显升高,SOD、GSH-Px活力明显降低(P<0.05).与IR组比较,R组再灌注30 min、1 h时心肌组织MDA含量降低,SOD、GSH-Px的表达增高(P<0.05).结论 大鼠急性肝缺血-再灌注可造成心肌细胞氧化损伤,而瑞芬太尼预处理可起到一定的保护作用.     

硫化氢预处理延迟相对大鼠心肌缺血-再灌注损伤的保护作用

目的探讨硫化氢预处理延迟相对大鼠心肌缺血-再灌注损伤的保护作用。方法将30只健康成年SD雄性大鼠随机分为三组:假手术组(S组)、缺血-再灌注组(IR组)和硫化氢组(H组)。S组仅开胸并分离冠状动脉左前降支,但不阻断血流150min;IR组行冠状动脉左前降支阻断30min,再灌注120min;H组予以静脉注射NaHS0.05mg/kg,给药后24h同IR组处理。再灌注结束后检测血清超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量和心肌梗死面积,电镜观察各组心肌细胞超微结构变化。结果与IR组比较,H组MDA含量降低,SOD活性增高(P<0.05),心肌梗死面积减少(P<0.05),电镜下H组心肌细胞损伤程度减轻。结论硫化氢预处理延迟相对大鼠缺血-再灌注心肌具有保护作用,与抗氧化反应有关。     

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.     

二氮嗪预处理对大鼠心肌缺血-再灌注损伤的保护作用

目的观察二氮嗪预处理对在体大鼠心肌缺血-再灌注损伤的保护效果,并对其作用机制进行初步的探讨。方法健康SD大鼠14只,采用随机数余数分组法分为两组,对照组和二氮嗪预处理组,每组7只。二氮嗪预处理组按12.5mg/kg的剂量静脉注射二氮嗪溶液,对照组在心肌缺血前静脉注射等量溶媒溶液,结扎冠状动脉前降支致缺血2h,再灌注2h后取心脏,检测缺血心肌组织丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、心肌梗死面积,观察缺血区凋亡心肌细胞和心肌细胞超微结构的改变。结果二氮嗪预处理组缺血心肌组织MDA含量、心肌梗死区占缺血区的重量百分比和心肌细胞凋亡率明显低于对照组(P<0.05,0.01),心肌超微结构损伤明显轻于对照组。结论二氮嗪预处理对在体大鼠心肌缺血-再灌注损伤具有较好的保护作用。     

七氟醚预处理联合后处理对大鼠心肌缺血-再灌注损伤的影响

目的 探讨七氟醚预处理联合后处理对大鼠缺血-再灌注损伤心肌的保护作用及其相关机制.方法 清洁级成年雄性SD大鼠40只,体重230～270 g,采用随机数字表法,将其均分为五组:假手术组(S组)、心肌缺血-再灌注组(IR组)、七氟醚预处理组(SP1组)、七氟醚后处理组(SP2组)、七氟醚预处理联合后处理组(SS组).除S组外均采用结扎左冠状动脉前降支30 min,再灌注120 min的方法制备大鼠心肌缺血-再灌注模型,S组只穿线,不结扎;SP1和SP2组分别于缺血前30min、再灌注前10 min吸入2.5％七氟醚15 min,洗脱15 min;SS组于缺血前30 min和再灌注前10min均吸入2.5％七氟醚15 min,洗脱15 min.于缺血前30 min、缺血30 min、再灌注120 min时记录HR和MAP,计算RPP(SBP×HR).于再灌注120 min时取心脏制病理切片,光镜下观察各组心肌病理学变化,测定凋亡指数(AI),检测心肌组织SOD和MDA含量,免疫组化法检测心肌组织TNF-α和caspase-3的表达.结果 与S组比较,其余四组再灌注120 min时MAP和RPP明显降低,AI明显升高,心肌组织SOD含量明显降低,MDA含量明显升高,TNF-α和caspase-3表达明显增高(P＜0.05);与IR组比较,SP1组、SP2组和SS组AI明显降低,心肌组织SOD含量明显升高,MDA含量明显降低,TNF-α和caspase-3表达明显降低(P＜0.05);与SP1组和SP2组比较,SS组AI明显降低,心肌组织SOD含量明显升高,MDA含量明显降低,TNF-α和caspase-3表达明显降低(P＜0.05).结论 与单纯七氟醚预处理或后处理比较,两种方法联合应用可使心肌组织AI降低,SOD含量升高,MDA含量降低,TNF-α和caspase-3的表达降低,从而进一步减轻了大鼠心肌缺血-再灌注损伤.     

大鼠血红素加氧酶-1基因转染对大鼠离体心肌缺血再灌注心肌细胞凋亡的影响

目的 观察重组腺相关病毒介导大鼠血红素加氧酶-1基因转染对大鼠离体心肌缺血再灌注心肌细胞凋亡的影响.方法 雄性SD大鼠30只随机分成3组,对照组(C组,n=6),缺血再灌注组(I/R组,n=12),腺相关病毒介导血红索加氧酶-1基因组(A-r组,n=12).基因转染3个月后,建立大鼠离体心脏Langendorff灌流模型,C组持续灌注100 min,其他各组均平衡15 rain,停灌40min与再灌注45 min,记录冠脉流量(CF),测定冠脉流出液肌酸激酶(CK)活性,测定再灌注后45 min时的心肌心肌组织超氧化物岐化酶(SOD)活性活性及丙二醛(MDA)含量,同时取每组大鼠心肌检测梗死面积、心肌细胞凋亡率以及心肌组织bax、bcl-2蛋白表达量.结果 离体心肌Langendorff灌注后,与I/R组比较,A-r组在复灌后冠脉流出液CK活性降低(P＜0.01),复灌后45min后心肌MDA含量降低(P＜0.01),SOD活性增高(P＜0.01),梗死面积较小(P＜0.01),心肌组织bax表达量、心肌细胞凋亡率均显著下降,心肌组织bel-2表达量明显增加(P＜0.01).结论 重组腺相关病毒血红素加氧酶1基因转染心肌后,可抑制离体缺血再灌注心肌细胞凋亡和增强心肌抗氧化能力,对大鼠离体心肌缺血再灌注损伤有显著保护作用.     

缺血后处理对猪心肌细胞Fas基因蛋白表达及Caspase-3活性的影响

目的探讨缺血后处理对猪心肌细胞Fas基因蛋白表达及Caspase-3活性的影响。方法24只小型约克猪(体重35～40kg)被随机分为4组。组1(ACC组,n=6)：于CPB开始后并行循环45 min,阻断主动脉90 min,开放主动脉后心脏再灌注120 min；组2(pre-con组,n=6)：升主动脉阻断前进行心脏缺血预处理(阻断升主动脉5 min、开放10 min,重复3次),余处理与组1相同；组3(post-con组,n=6)：并行循环45 min,阻断主动脉90 min,开放主动脉后心脏再灌注120 min；再灌注开始进行缺血后处理(阻断升主动脉30 s后开放30 s,重复3次,共3 min)；组4(pre-con +post-con组,n=6)：升主动脉阻断前进行心脏缺血预处理(阻断升主动脉5 min、开放10 min,重复3次),阻断主动脉90 min,开放主动脉心脏再灌注120 min,再灌注开始进行心肌缺血后处理(阻断升主动脉30 s、开放30 s,重复3次共3 min)。在再灌注结束后取左心室全层心肌适量并固定。用原位化学法(TUNEL)观察各组心肌细胞凋亡,流式细胞法检测Fas基因蛋白表达及Caspase-3的活性。在CPB前、缺血90 min、再灌注30、60、120 min采静脉血检测血MDA、SOD水平。结果原位化学法测得心肌细胞凋亡率组2(10．46±0．91)%、组3(9．68±0．59)%和组4(11．35±1．37)%显著低于组1(19．75±1．81)%(P＜0．05)；流式细胞法测得Fas,Caspase-3荧光表达指数(FI),组2(1．24±0．13和1．32±0．13)、组3(1．27±0．07和1．33±0．08)和组4(1．27±0．14和1．31±0．12)显著低于组1(1．74±0．11和1．99±0．12)(P＜0．05)；与组1相比,MDA血浆浓度组2、组3和组4显著低于组1,而SOD浓度却显著高于组1(P＜0．05)。组2、组3和组4上述指标差异无统计学意义(P＞0．05)。结论Fas、Caspase-3表达改变参与了心肌细胞凋亡及缺血再灌注损伤过程；缺血后处理可以明显减少心肌细胞凋亡,抑制缺血再灌注损伤。心肌细胞凋亡的减少与Fas基因蛋白的下调、抑制Caspase-3活性及氧化应激有关；缺血后处理与缺血预处理相比可以同等程度的减少心肌细胞凋亡。本实验未观察到缺血预处理和缺血后处理的叠加作用。     

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.     

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.     

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.     

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.