异丙酚和普鲁卡因对离体中性粒细胞粘附功能的影响

目的 研究异丙酚或/和普鲁卡因对离体中性粒细胞（PMN）粘附分子CD18,CD62L（L-选择素）表达、超氧化物阴离子（SOA）释放及全血中IL-6、TNF-α生成的影响。方法 提纯PMN并用磷酸盐缓冲液（PBS）制成悬液,样本分为九组:空白组（PMN+PBS）,损伤组（PMN+PMA 100ng·ml-1）,异丙酚1、2、3组（PMN+PMA 100ng·ml-1+异丙酚0.4、4或40μg·ml-1）,普鲁卡因1、2、3组（PMN+PMA100ng·ml-1+普鲁卡因 1.5、15 或150μg·ml-1）及异-普复合组（PMN+PMA100ng·ml-1+异丙酚 2μg·ml-1+普鲁卡因 8μg·ml-1）。另设相应浓度药物组。流式细胞仪检测 CD18、CD62L表达,细胞色素C还原法测定 SOA释放。另取全血,以内毒素1μg·ml-1刺激,分组处理同上,采用放免法测定IL-6、TNF-α的生成。结果 异丙酚抑制PMN粘附分子表达及SOA释放的效应强于普鲁卡因,异-普复合效应与异丙酚接近。异丙酚促进全血中细胞因子生成,普鲁卡因显示抑制作用,异-普复合效应与普鲁卡因接近。结论 一定浓度的异丙酚或/和普鲁卡因对中性粒细胞粘附功能有抑制作用。     

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.     

靶控输注芬太尼对异丙酚药代动力学的影响

目的 探讨靶控输注芬太尼对异丙酚药代动力学的影响。方法 24例行结肠或直肠癌根治术患者,AsAⅠ-Ⅱ级,随机分为异丙酚复合硬膜外组(A组,n=8),异丙酚复合2 ng·ml-1芬太尼组(B组,n=8),异丙酚复合4 ng·ml-1芬太尼组(C组,n=8),三组患者均采用靶控方式输注芬太尼与异丙酚,异丙酚靶浓度均为3μg·ml-1。测定靶控输注中及停止输注后异丙酚的血浆浓度,并拟合得到各项药代动力学参数。结果 异丙酚药代动力学模型符合三室开放模型。药代动力学参数:快速分布半衰期(t1/2α)、慢速分布半衰期(t1/2β)、消除半衰期(t1/2γ)、浓度-时间曲线下面积(AUC)、清除率(CL)及中央室容积(Vc),各组间比较差异无显著性(P>0.05)。结论 靶控输注临床剂量的芬太尼(2ng·ml-1与4 ng·ml-1)并不影响异丙酚的药代动力学特性。     

PI3K/AKT信号通路在异丙酚减轻离体大鼠心脏缺血再灌注损伤中的作用

目的 探讨PI3K／AKT信号传导通路在异丙酚减轻离体大鼠心脏缺血再灌注损伤中的作用。方法 成年SD大鼠32只，随机分为4组：缺血再灌注组（I／R组）、异丙酚组（P组）、渥曼青霉素组（W组）和异丙酚＋渥曼青霉素组（PW组），每组8只。建立Langendorff离体心脏灌注模型，灌注压10kPa,灌注速率7．10ml／min，I／R组用K-H液灌注，P组用含50μmol／L异丙酚的K-H液灌注，W组用含100nmol／L渥曼青霉素的K-H液灌注；PW组用含50μmol／L异丙酚＋100nmol／L渥曼青霉素的K-H液灌注，灌注15min，全心缺血30min，再灌注60min。测定再灌注10、40min时冠脉流出液中心肌肌钙蛋白（cTnI）浓度，再灌注60min时测定心肌组织丙二醛（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 与I／R组比较，P组再灌注期间cTnI浓度明显降低，心肌组织SOD活性升高，MDA含量降低（P〈0．05），其余2组上述指标差异无统计学意义（P〉0．05）；与缺血前比较，P组再灌注40min时cTnI浓度升高，其余各组再灌注期间cTnI浓度均升高（P〈0．05或0．01）。P组电镜下心肌超微结构改变减轻。结论 异丙酚减轻离体大鼠心脏缺血再灌注损伤可能通过PI3K／AKT信号传导通路介导。     

吡那地尔超极化停搏对大鼠离体心脏蛋白激酶C及热休克蛋白70的影响

目的探讨吡那地尔超极化停搏对大鼠离体心脏蛋白激酶C（PKC）ε及热休克蛋白70 （HSP70）的影响。方法成年雄性SD大鼠,成功建立Langendorff离体再灌注模型的32个心脏,随机分为4组（n=8）：自然停搏组（A组）、St.Thomas组（B组）、吡那地尔超极化组（C组）和白屈菜赤碱组（D组）。A组、B组和C组K-H液平衡灌注15min后,A组停止灌注,B组灌注St.Thomas停搏液,C组灌注超极化停搏液;D组K-H液平衡灌注10min后,白屈菜赤碱液灌注5min,再灌注超极化停搏液。记录各组平衡灌注15min和再灌注20min时冠脉流量（CF）、心率（HR）、左室发展压（LVDP）、左室收缩峰压（LVSP）和左室压力瞬时最大变化率（dp/dtmax）;再灌注30min时测定心肌膜性PKCε和HSP70的表达。结果与K-H液平衡灌注15min时相比,再灌注20min时A组、B组和D组CF、HR、LVSP、LVDP及dp/dtmax降低（P〈0.05）;与C组相比,其余各组再灌注20min时CF、HR、LVSP、LVDP及dp/dtmax降低,膜性PKCε和HSP70的表达下调（P〈0.05）。结论吡那地尔超极化停搏通过上调膜性PKCε和HSP70表达,促进大鼠心肌缺血再灌注时心功能恢复。     

一氧化氮在异丙酚减轻大鼠离体心脏缺血再灌注损伤中的作用

目的 探讨一氧化氮在异丙酚减轻大鼠离体心脏缺血再灌注损伤中的作用.方法 成年雄性SD大鼠,体重220～330 g,采用Langendorff装置建立大鼠离体心脏灌注模型,选取符合实验标准的心脏模型18个,随机分为3组(n=6):K-H液灌注组(A组)、异丙酚灌注组(B组)和异丙酚+L-NAME灌注组(C组).各组用相应的K-H液灌注15 min,常温全心停灌20 min,然后用相应的K-H液复灌60 min.采用电化学微传感器法测定心肌一氧化氮(NO)含量,免疫组化法测定心肌一氧化氮合酶(NOS)含量,分光光度计测定心肌NOS活性,测定心率、左心室舒张末压、左心室发展压、左心室压变化速率最大值和左心室压变化速率最小值,定时收集右心室流出液以测定冠脉流量.结果 与A组相比,B组和C组复灌后各时点心功能改善(P＜0.05);与C组相比,B组复灌后各时点心功能改善(P＜0.05);B组心肌NO含量和NOS活性较A组升高(P＜0.05),但2组心肌NOS含量差异无统计学意义(P＞0.05).结论 缺血再灌注导致心肌内源性NO的含量降低.异丙酚减轻大鼠离体心脏缺血再灌注损伤可能是通过增加心肌内源性NO生成实现的.     

芬太尼对培养心肌细胞缺氧-再给氧损伤的保护作用

目的 研究芬太尼对培养心肌细胞缺氧-再给氧损伤的保护作用。方法 原代培养乳鼠心肌细胞,建立培养心肌细胞缺氧-再给氧损伤模型。将培养6d的乳鼠心肌细胞随机分为5组:对照组、单纯缺氧-再给氧组以及缺氧-再给氧前分别加芬太尼10 ng·ml-1、30 ng·ml-1和 50ng·ml-1组,实验结束测定心肌细胞存活数量、细胞内丙二醛（MDA）含量及培养瓶的上清液中乳酸脱氢酶（LDH）和肌酸激酶（CK）的活性。结果 与对照组相比,单纯缺氧-再给氧组使细胞内MDA含量、LDH和CK活性显著升高（P<0.01）及心肌细胞存活数量明显下降（P<0.01）。加入30ng·ml-1和50ng·ml-1芬太尼均能显著减轻细胞内MDA含量、LDH和CK活性的升高及心肌细胞存活数量的下降（P<0.01）,而加入10ng·m-1芬太尼无明显变化。结论 芬太尼对培养心肌细胞的缺氧-再给氧损伤具有保护作用。     

七氟醚对低温全心缺血-再灌注心脏电传导及Cx43 Ser368磷酸化的影响

目的 观察七氟醚对低温全心缺血-再灌注心室肌电传导及Cx43 Ser368磷酸化的影响。
方法 制备成功的离体灌注工作心脏24只,随机分为三组：对照组（C组）、低温全心缺血-再灌注组（IR组）和1.0 MAC七氟醚处理组（Sev组）,每组8只。C组：37 ℃ K-H液平衡灌注15 min后继续灌注37 ℃ K-H液105 min;IR组：37 ℃ K-H液平衡灌注15 min后继续灌注37 ℃ K-H液15 min,注射Thomas液（4 ℃,20 ml/kg）使心脏停搏60 min,4 ℃ K-H液保护心脏,停搏30 min时半量复灌Thomas液（4 ℃,10 ml/kg）,60 min时使用37 ℃ K-H液再灌注30 min;Sev组：37 ℃ K-H液平衡灌注15 min后继续灌注含饱和1.0 MAC七氟醚的37 ℃ K-H液15 min,注射Thomas液（4 ℃,20 ml/kg）使心脏停搏60 min,4 ℃ K-H液保护心脏,停搏30 min时半量复灌Thomas液（4 ℃,10 ml/kg）,60 min时使用含饱和1.0 MAC七氟醚的37 ℃ K-H液再灌注30 min。于再灌注即刻至灌注结束,记录离体心脏复跳时间（再灌注即刻至心脏首次跳动所需的时间）,室性心律失常（室性早搏、室性心动过速、室性颤动）发生情况和持续时间。采用心脏刺激仪行程控刺激,测定并记录有效不应期（ERP）、传导速度(CV）。采用免疫印迹法检测心室肌组织Cx43和Cx43 Ser368蛋白相对含量。
结果 与C组比较,IR组和Sev组ERP明显延长,CV明显减慢（P＜0.05）;IR组Cx43及Cx43 Ser368蛋白相对含量明显降低（P＜0.05）。与IR组比较,Sev组心脏复跳时间明显缩短,心律失常发生率明显降低,心律失常持续时间明显缩短,ERP明显缩短,CV明显增快,Cx43及Cx43 Ser368蛋白相对含量明显升高（P＜0.05）。
结论 七氟醚可以上调低温全心缺血-再灌注心室肌组织Cx43和Cx43 Ser368的表达,促使心室肌电传导增快、有效不应期缩短,降低再灌注心律失常的发生。     

低温缺血再灌注心律失常大鼠心室肌电传导的变化

目的评价低温缺血再灌注心律失常大鼠心室肌电传导的变化。方法清洁级健康成年雄性SD大鼠,2～3月龄,体重200～300 g,取成功建立Langendorff灌注模型的离体心脏16个,采用随机数字表法分为2组(n=8),正常对照组(C组):平衡灌注37 ℃ K-H液120 min;低温缺血再灌注组(I/R组):平衡灌注37 ℃ K-H液30 min后,注射4 ℃ Thomas液使心脏停搏后停灌K-H液,心脏周围用低温(4 ℃)Thomas液保护,30 min时半量复灌Thomas液(4 ℃),停灌60 min时再灌注K-H液30 min。将I/R组分为高危亚组(IR-H亚组)和低危亚组(IR-L亚组)。再灌注末通过程控电刺激法测定房室传导2∶1阻滞点(2∶1B)及心室电传导速度(CV)。记录心脏复跳时间和心律失常发生情况。结果与C组比较,IR-L亚组和IR-H亚组CV减慢,2∶1B降低(P<0.05);与IR-L亚组比较,IR-H亚组心脏复跳时间延长,复跳后室颤发生率及心律失常评分升高,CV减慢,2∶1B降低(P<0.05)。结论低温缺血再灌注心律失常大鼠心室肌电传导速度减慢,...     

异丙酚对离体人支气管平滑肌的作用

目的 观察异丙酚对离体人肺叶支气管平滑肌的作用。方法 离体人肺叶支气管取自胸外科肺叶切除术患者（n=10）,采用离体气管实验法,以乙酰胆碱（3μg·ml-1）激发,观察临床相关剂量的异丙酚（1、2、5、10、20μg·ml-1）对离体人肺叶支气管平滑肌的作用,脂肪乳剂作为对照。结果与对照组相比,1、2、5、10、20μg·ml-1的异丙酚显著减弱乙酰胆碱的平滑肌收缩反应（P值分别<0.05、<0.01、<0.01、<0.01、<0.01）。结论 临床相关剂量的异丙酚可有效地减弱乙酰胆碱介导的离体人肺叶支气管平滑肌的收缩反应.     

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.     

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.     

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.