戊二醛处理兔颈静脉移植物对内膜增生的影响

目的 观察戊二醛对静脉移植物内膜增生的影响.方法 60只新西兰大白兔随机分为实验组和对照组,实验组静脉移植物用1%戊二醛溶液浸泡10 min,对照组用生理盐水浸泡10 min.分别于移植后4、12周时观察内膜增生情况;对平滑肌细胞肌动蛋白α(α-actin)、增殖细胞核抗原(PCNA)行免疫组织化学染色;行原位末端标记法(TUNEL)染色观察细胞凋亡.结果 术后4周和12周,实验组平滑肌细胞明显少于对照组,内膜厚度(0.016±0.004)、(0.031±0.008)mm小于对照组(0.025±0.005)、(0.093±0.024)m(P<0.05),但两组细胞增殖率差异无统计学意义(P>0.05).细胞凋亡率实验组(3.3±0.7)%、(6.7±1.5)%高于对照组(1.2±0.4)%、(1.8±0.5)%(P<0.05).结论 戊二醛处理静脉移植物可显著减少移植物平滑肌细胞数目并抑制内膜增生.     

重组arresten蛋白对自体移植静脉内膜增生的抑制作用

目的 观察原核表达人arresten重组蛋白对自体移植静脉内膜增生的抑制作用.方法 用pRSET原核表达系统表达并纯化人arresten重组蛋白.将Wistar大鼠颈外静脉移植于腹主动脉,建立大鼠自体静脉移植模型,实验分3组:假手术组、移植对照组和移植实验组.自术后第3天起,皮下注射给予arresten重组蛋白(每日4 mg/kg体重)处理.4周后取移植静脉组织标本,进行病理组织学观察与免疫组织化学染色分析.结果 移植组移植静脉均呈现典型的内膜增生、肥厚,导致血管管腔狭窄;新生内膜主要有过度增殖的α-SMA染色阳性平滑肌细胞组成.移植实验组移植静脉内膜增生受到明显抑制,新生内膜面积(0.12±0.07)mm2及新生内膜/中膜面积比(0.373±0.085)均显著低于对照组[(0.38±0.11)mm2,1.621±0.086,P<0.01];并且实验组移植静脉新生内膜细胞PCNA标记指数显著低于对照组[(15.62±3.97)%比(56.36±3.49)%,P<0.01].结论 重组arresten蛋白通过抑制新生内膜平滑肌细胞的增殖能有效抑制自体移植静脉内膜增生的发生发展,在防治血管重建术后再狭窄方面显示出良好的应用前景.     

伊马替尼抑制大鼠静脉移植物内膜增生

目的 观察伊马替尼对自体移植静脉内膜增生的影响.方法 建立大鼠自体颈外静脉移植模型,实验分为4组:移植组、低剂量给药组、高剂量给药组及对照组.移植4周后取移植静脉,行病理学检查观察内膜增生情况,免疫组织化学及Western blot法检测PDGFRβ、ERK及P-PDGFRβ、P-ERK蛋白表达情况.结果与对照组比较,移植组和低剂量给药组内皮下平滑肌细胞大量增生,静脉内膜显著增厚,管腔明显狭窄,高剂量给药组内膜无明显增厚.Western blot结果显示,移植组血管P-PDGFRβ蛋白含量(P-PDGFRβ/GAPDH)较对照组明显增加(0.81±0.06比0.18±0.02,P<0.05),而高剂量给药组较移植组明显减少(0.32±0.03比0.81±0.06,P<0.05),低剂量给药组与移植组比较差异无统计学意义(P>0.05),P-ERK蛋白表达亦呈同样趋势变化.结论 高剂量伊马替尼能有效抑制自体移植静脉内膜增生,其机制可能与抑制PDGF信号通路蛋白磷酸化,从而抑制平滑肌细胞增殖有关.     

去势对雄性大鼠血管成形术后再狭窄的影响

目的 :系统观察血管外膜细胞在血管成形术 (PTA)后再狭窄过程中的动态变化 ,通过复制去势模型对照观察雄激素对再狭窄的影响 ,并探讨其作用机制。　方法 :复制雄性SD大鼠的去势模型及颈总动脉再狭窄模型 ,于术后 3、7、14、2 8d不同时间点取材 ,行苏木精 伊红染色及免疫组化染色 ,并以电镜观察血管狭窄情况。　结果 :PTA术后 3d增殖细胞首先出现在血管外膜 ,并发生表型转变 ,术后 7d时外膜细胞增殖最明显 ,并向内膜迁移 ,术后 14d外膜细胞增殖减少 ,增殖细胞集中于中膜及新生内膜。各观察时间点 ,去势雄性大鼠的血管外膜面积、新生内膜面积、血管狭窄程度 ,均较未去势组大。以 14d组为例 ,血管外膜面积 [(35 6 6± 337) μm2 vs (2 75 1± 4 0 1) μm2 ,P =0 .0 0 8],新生内膜面积 [(35 5 3± 4 77) μm2 vs (2 75 7± 4 35 ) μm2 ,P =0 .0 2 5 ],血管狭窄程度 [(76± 2 ) %vs (6 0±8) % ,P =0 .0 0 5 ],外膜细胞增殖指数 [(2 9± 2 ) %vs (13± 1) % ,P <0 .0 0 1]。　结论 :PTA术后血管外膜细胞增殖、迁移参与了再狭窄的形成。生理状态下体内雄激素可以减轻血管再狭窄程度 ,其作用机制可能与干预血管外膜细胞活化有关。     

微泡造影剂结合超声介导一氧化氮合成酶基因转染防治移植静脉再狭窄

目的 探讨微泡造影剂及超声辐照介导内皮型一氧化氮合成酶(eNOS)基因转染防治移植静脉血管桥再狭窄的可行性.方法 重组真核表达载体pcDNA3.1-eNOS经微泡造影剂及超声辐照介导体外转染大鼠颈外静脉,再将静脉段间置植入颈总动脉,建立SD大鼠颈外静脉-颈总动脉移植模型.于术后4周取移植静脉标本分别进行苏木素-伊红(HE)染色,免疫组织化学染色及Western blot法分析,观察eNOS基因在静脉桥中的功能表达和静脉桥新生内膜的增生.结果 Western blot法分析表明微泡造影剂及超声辐照介导eNOS基因转染组的移植血管桥内eNOS表达最明显;增殖细胞核抗原( PCNA)检测阳性率为(21.04±3.51)％,细胞凋亡指数为(12.11±1.23)％,新生内膜厚度(25.0±3.5) μm,内膜/中膜比值为0.43,均明显低于其他组(P＜0.05).结论 微泡造影剂及超声辐照介导eNOS基因转染可以有效抑制移植静脉桥新生内膜的增生.     

反义c-fos核酸对自体移植静脉内膜增生的影响

目的:利用反义核酸技术和显微外科技术,探讨反义c-fos核酸对自体移植静脉内膜增生的影响.方法:选择20只新西兰家免,等分为实验组和对照组,均行自体颈外静脉、颈总动脉移植手术,实验组移植静脉周围和血管吻合口周围应用反义c-fos核酸凝胶涂布;对照组仅行凝胶涂布.术后2周取出移植血管,分别行病理学、免疫组织化学检测移植血管内膜厚度,内膜平滑肌细胞数及PCNA阳性表达情况.结果:实验组移植血管内膜厚度、管腔狭窄度及VSMC数均较对照组减少,PCNA阳性表达情况亦较对照组明显减少.结论:反义c-fos核酸可有效的抑制移植静脉内膜的增生,是一种比较有发展前途的防治移植静脉内膜增生的基因疗法.     

细胞外信号调节激酶和P38蛋白激酶在自体移植静脉中的表达

目的研究丝裂原活化蛋白激酶亚单位细胞外信号调节激酶(ERK)和p38蛋白激酶(p38 MAPK)在移植静脉血管重塑过程中的表达.方法选Wistar大鼠80只,建立自体移植静脉模型,术后随机分为6 h、24 h、3 d、7 d、2周、4周、6周及8周组,于相应时点取材,半定量逆转录PCR法检测移植血管中ERK和p38 MAPK的mRNA表达;Western蛋白印迹定量检测ERK和p38 MAPK的蛋白产物及磷酸化蛋白产物表达;脱氧核苷酸末端转移酶末端标记法(TUNEL)检测血管平滑肌细胞(VSMC)凋亡的变化;免疫组化检测增殖细胞核抗原(PCNA)的表达.结果移植静脉术后6 h,ERK1和p38 MAPK的mRNA表达均明显增强,与正常静脉组比较差异均有显著性意义(P＜0.01);ERK1mRNA表达在移植后7 d达高峰,表达值为(33.2±14.2)%,p38 MAPK的mRNA表达于术后2周达到高峰,表达值为(58.8±26.2)%,与其余各时点比较差异有显著性意义(P＜0.01).Western蛋白印迹提示ERK1/2在术后1～2周达高峰,6周时逐渐恢复至正常水平;而p38 MAPK则在移植后2～4周达高峰,之后开始减少,8周时仍维持一定表达量(1/4～1/2).ERK1与PCNA表达呈正相关(r=0.759 6,P＜0.01),p38 MAPK与凋亡呈正相关(r=0.892 2,P＜0.01).结论MAPK的激活是移植静脉内膜增生以及血管重塑的关键环节,可能成为防治移植静脉狭窄、闭塞的新的治疗靶点.     

血管外雷帕霉素缓释涂层抑制移植静脉再狭窄

目的观察血管周围局部应用雷帕霉素对兔自体移植静脉段内膜过度增殖的抑制作用,并初步探讨其作用机制。方法大耳白兔30只,采用自身对照设计建立模型。任取一侧静脉旁路为干预组,外涂含0.3 mg雷帕霉素的Pluronic凝胶;另一侧为对照组,外涂空凝胶。4周后测旁路静脉内膜厚度、细胞的增殖指数及PCNA、P27~(kipl)免疫组化阳性细胞数。并于术后1、2、4、8周检测血管壁中雷帕霉素的含量。结果干预组旁路静脉内膜厚度(63.72±14.00)μm与对照组(77.76±14.90)μm相比,增生明显减少(P<0.05)。增殖指数对照组(29.30±7.15)明显高于干预组(20.10±9.48)(P<0.05)。在干预组和对照组均有阳性PCNA免疫组化染色表达细胞,正常静脉未见阳性表达,对照组较干预组细胞的阳性表达更强(P<0.05)。P27~(kipl)免疫组化染色干预组见阳性表达细胞,对照组表达阴性(P<0.05)。干预组血管壁术后1～8周均可测到雷帕霉素,含量呈逐步递减趋势。结论血管周围局部应用雷帕霉素具有抑制兔移植静脉内膜过度增殖的作用;这种作用和P27~(kipl)的上调表达有关。     

平滑肌22α启动子/增强子靶向调控哺乳动物雷帕霉素靶蛋白信号通路对移植血管平滑肌细胞增殖的影响

目的 采用血管平滑肌细胞(SM)特异性SM22α启动子/平滑肌肌球重链蛋白(SMHC)增强子,构建靶向大鼠哺乳动物雷帕霉素靶蛋白(mTOR)基因的干扰RNA真核表达载体,研究其对血管平滑肌细胞(VSMC)增殖及移植血管新生内膜增生的影响.方法 构建大鼠特异性SM22α真核表达载体SM22α-p/e-mTOR-短发卡RNA(shRNA),建立大鼠颈静脉-动脉移植模型,在血管吻合完成后通过Pluronic F-127质粒缓释系统对血管内平滑肌增殖进行局部RNA干扰.实验分5组,每组20只SD大鼠.A组:对照组(25％ Pluronic F-127组);B组:SM22α组(SM22α-p/e-mTOR-shRNA);C组:巨细胞病毒(CMV)组(CMV-p/e-mTOR-shRNA);D组:阴性对照组(空质粒pGenesil-10);E组:阳性对照组;其中,B组和C组统称实验组.根据实验分组的不同,将含有50 μg shRNA质粒,或50 μg渥曼青霉素(wortmannin)凝胶,或单纯200μl 25％ Pluronic F-127凝胶均匀涂抹在移植静脉周围,分别于术后1、3、7、14 d获取移植血管.苏木素-伊红(HE)染色观察新生内膜厚度;免疫组织化学检测平滑肌肌动蛋白(α-SM-actin)、增殖细胞核抗原(PCNA)、磷酸化-mTOR (Ser2448),原位末端转移酶标记技术(TUNEL)检测细胞凋亡,评估mTOR信号通路的变化以及平滑肌细胞的增殖.结果 术后7d各组新生内膜厚度差异有统计学意义(P＜0.05);术后14 d,A组新生内膜较术后1d增厚12.4倍;B、C、D、E组分别增厚9.7、4.8、7.6、2.6倍.术后14d,各实验组和阳性对照组移植静脉α-SM-actin表达阳性面积均明显低于对照组(P＜0.05),PCNA阳性表达面积均低于对照组(P＜0.05),磷酸化-mTOR(Ser2448)阳性表达面积均低于对照组(P＜0.05);实验组、对照组、阴性对照组术后移植静脉凋亡细胞阳性面积比较差异无统计学意义(P＞0.05),阳性对照组凋亡面积明显高于其他组(P＜0.05).结论 SM22α-p/e-mTOR-shRNA可通过抑制血管平滑肌细胞mTOR信号通路而抑制血管平滑肌细胞增殖,预防或延缓移植静脉狭窄.     

血管成形术后再狭窄中细胞增殖与凋亡的研究

目的　动态观察血管成形术后不同时间段增生内膜细胞凋亡、增殖的变化过程。方法　将新西兰大白兔 35只随机分成 7组 ,应用 2次损伤法建立兔髂动脉再狭窄模型 ,检测血管成形术后 5 6d内 7个不同时间段 ( 0、3、7、14、2 8、42、5 6d)增生内膜的细胞增殖、凋亡指数及内膜面积、内膜细胞数。结果　血管成形术后内膜细胞凋亡与增殖的变化并不是同步的 ,术后第 7天凋亡指数达到高峰 ,为 ( 2 2 .81± 4.19) % ,增殖指数在术后第 14～ 2 8天最高 ,但峰值较低 ,分别为( 16 .2 1± 1.78) %、( 15 .49± 1.6 1) %。结论　内膜细胞增殖与凋亡的失衡是决定再狭窄的重要因素。     

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.