异丙酚对大鼠海马CA1区突触传递可塑性的影响

目的研究异丙酚对海马CAl区突触传递和可塑性的影响。方法断头分离Wistar大鼠海马半脑,制备400μm厚度海马脑片。45张脑片分为六组。脂肪乳剂组和异丙酚组的脑片以印防己毒素预孵30min,然后加入450μl脂肪乳剂或异丙酚(相当于500μmol/L),观察对兴奋性突触后电流(EPSC)的影响。脂肪乳剂长时程增强(LTP)组、脂肪乳剂长时程抑制(LTD)组、异丙酚LTP组、异丙酚LTD组的脑片以90μl脂肪乳剂或异丙酚(相当于100 μmol/L)预孵60 min,给予高频刺激(HFS)或低频刺激(LFS),记录LTP或LTD的发生情况。结果 脂肪乳剂对EPSC无影响(P>0.05);500 μmol/L异丙酚使2/3细胞EPSC下降至基础值的67.5％(P<0.05),使1,3细胞EPSC上升至基础值的140.3％(P<0.05)。脂肪乳剂LTP组给予HFS后EPSC值为基础值的151.6％(P<0.05),脂肪乳剂LTD组给予LFS后EPSC值为基础值的57.9％(P<0.05);异丙酚LTP组给予HFS后,LTP可以产生但不能维持,HFS后EPSC值为基础值的98.8％(P>0.05),异丙酚LTD组给予LFS后EPSC值为基础值的40.8％(P<0.05),明显低于脂肪乳剂LTD组(P<0.05)。结论异丙酚对大鼠海马CAl区突触传递具有双重影响,出现抑制和兴奋两种效果;异丙酚损害大鼠海马CAl区锥体神经元LTP的维持而易化LTD。     

丙泊酚对大鼠海马CA1区长时程抑制的影响

目的　观察丙泊酚对大鼠海马CA1区锥体神经元产生的长时程抑制 (LTD)的影响 ,并分析其可能机制。方法　断头法分离wistar大鼠 (13～ 19d)海马半脑 ,用切片机切出 4 0 0 μm厚度的海马脑片。实验分三组 :脂肪乳剂组 (I组 ) ,丙泊酚组 (P组 ) ,SR95 5 31+丙泊酚组 (GP组 )。I组和P组以 90 μL脂肪乳剂或丙泊酚 (相当于 10 0 μmol/L)预孵脑片 6 0min ,然后给予低频刺激 (LFS) ,记录LTD的表达情况 ;GP组先在循环液中加入 10 μmol/LSR95 5 31预孵脑片 30min ,再加入 10 0 μmol/L丙泊酚继续孵育 6 0min ,继而给予LFS ,记录LTD的表达情况。结果　I组给予LFS后 ,产生LTD ,LFS后 10～ 4 0min的兴奋性突触后电流 (EPSC)值为基础值的 5 7 85 % ;P组给予LFS后 10～ 4 0min的EPSC值为基础值的 4 0 82 % ,明显低于I组 (P <0 0 5 ) ;GP组给予LFS后 10～ 4 0min的EPSC值为基础值的 5 6 5 1% ,与I组比较差异无显著意义 (P >0 0 5 ) ,与P组比较差异有显著意义 (P <0 0 5 )。结论　 10 0 μmol/L丙泊酚使大鼠海马CA1区锥体神经元LTD表达增强 ,这种作用与其增强GABAA 受体功能有关 ;当阻断GABAA 受体后 ,这种易化作用消失     

异丙酚对大鼠海马CA1区神经元兴奋性突触传递的影响

目的 研究异丙酚对大鼠海马CA1区神经元兴奋性突触后电流（EPSC）和自发性兴奋性突触后电流（sEPSC）的影响。方法 Wistar大鼠断头后分离海马脑组织，制成400μm厚度的海马脑片，脑片随机分为5组（n=10）。脂肪乳剂Ⅰ组、异丙酚Ⅰ组、SR95531＋异丙酚组：记录EPSC10min（基础值）后分别加入10％脂肪乳剂90μl,1％异丙酚90μl（相当于100μmol／L）、10μmol／LSR95531＋100μmol/L异丙酚，继续记录EPSC40min，分析EPSC幅值的变化。脂肪乳剂Ⅱ组、异丙酚Ⅱ组：细胞破膜后稳定10．15min，分别加入10％脂肪乳剂90出和1％异丙酚90出，记录sEPSC40min，分析sEPSC频率、幅值和半衰期的变化。膜钳制电压均为-70mV。结果 与基础值比较，给药后脂肪乳剂Ⅰ组和SR95531＋异丙酚组EPSC幅值差异无统计学意义，异丙酚Ⅰ组EPSC幅值降低；给药后异丙酚Ⅰ组EPSC幅值比脂肪乳剂Ⅰ组降低（P〈0．05）。与脂肪乳剂Ⅱ组比较，异丙酚Ⅱ组sEPSC的频率、幅值降低、半衰期缩短（P〈0．05）。结论 异丙酚主要通过增强大鼠海马CA1区神经元突触前膜和突触后膜的GABA．受体活性，产生突触前抑制和突触后抑制，从而抑制兴奋性突触传递。     

丙泊酚对大鼠海马CA1区动作电位发放的影响

目的观察丙泊酚对大鼠海马CA1区动作电位(AP)发放的影响。方法断头法分离Wistar大鼠海马半脑,切片机切出400μm厚度的海马脑片。20张脑片分为两组:脂肪乳剂组和丙泊酚组,每组10张。应用电流钳技术,给予大鼠海马CA1区锥体神经元胞体以不同强度的电流刺激:从0nA到0.45nA,以0.05nA递增,共记录10sweeps,不同强度刺激间隔时间为10s,在CA1区神经元胞体记录加入90μl脂肪乳剂或丙泊酚(相当于100μmol/L)前后不同时间、不同刺激强度下AP的发放情况。膜钳制电流为0nA。结果脂肪乳剂没有影响胞体动作电位的数目和幅值;100μmol/L丙泊酚明显减少不同刺激强度下胞体动作电位产生的个数,加入丙泊酚40min后,动作电位基本消失;而且动作电位的幅值随时间而变化,加入丙泊酚前为(113±11)mV,加入丙泊酚后20min内幅值无明显变化,30min后降至(91±5)mV(P<0.05)。结论丙泊酚可能通过抑制钠通道和开放氯通道而减慢神经元动作电位的发放频率和降低其幅值。     

γ-氨基丁酸受体和甘氨酸受体在大鼠丙泊酚麻醉中的作用

目的研究丙泊酚对大鼠海马CA1区电刺激诱发兴奋性突触后电流(EPSC)的影响,分析γ-氨基丁酸(GABA)受体和甘氨酸受体在丙泊酚麻醉中的作用。方法断头法分离wistar大鼠(13～19d)海马半脑,切出400μm厚度的海马脑片,全细胞膜片钳技术记录CA1区锥体神经元EPSC。80张脑片分为八组:脂肪乳剂组,50μmol/L丙泊酚组,100μmol/L丙泊酚组,200μmol/L丙泊酚组,SR95531组,士的宁组,SR95531 100μmol/L丙泊酚组,士的宁 100μmol/L丙泊酚组,每组10张。SR95531 100μmol/L丙泊酚组和士的宁 100μmol/L丙泊酚组先在循环液中加入10μmol/LSR95531或4μmol/L士的宁预孵脑片30min。八组均记录基础EPSC10min,然后加入不同药物,继续记录EPSC40min。膜钳制电压为-70mV。结果脂肪乳剂、SR95531和士的宁对EP-SC幅值无影响;丙泊酚呈剂量依赖性的抑制EPSC幅值,50、100、200μmol/L丙泊酚最大抑制EPSC幅值为14.4%、52.3%、67.8%;SR95531 100μmol/L丙泊酚组加入丙泊酚后,EPSC幅值基本无改变;士的宁 100μmol/L丙泊酚组加入丙泊酚后,EPSC幅值仍然下降,最大抑制程度为34.7%。结论丙泊酚主要通过增强GABAA受体功能使兴奋性突触活动降低,甘氨酸受体在其中起到协同和调节作用。     

丙泊酚对大鼠海马CA1区兴奋性突触传递的影响

目的观察500μmol/L丙泊酚对大鼠海马CA1区电刺激诱发的兴奋性突触后电流(EPSC)的影响,分析丙泊酚的可能作用机制。方法断头法分离Wistar大鼠(13~19d)海马半脑,用切片机切出400μm厚度的海马脑片,全细胞膜片钳技术记录CA1区锥体神经元EPSC。实验分两组:脂肪乳剂组(n=6)和丙泊酚组(n=10)。先以50μmol/L印防己毒素预孵脑片30min后,记录基础EPSC10min,然后加入450μl脂肪乳剂或丙泊酚(相当于500μmol/L),继续记录EPSC40min;继而以配对刺激代替单刺激,观察EPSC2/EPSC1比率的变化;改变膜钳制电压(-80~+60mV),观察电流-电压(I-V)曲线的变化。结果脂肪乳剂对EPSC无影响,500μmol/L丙泊酚降低大鼠海马CA1区EPSC值,25~30min左右达最大抑制效果,EPSC幅值下降至基础值的67·5%,明显低于脂肪乳剂组(P<0·05);而且500μmol/L丙泊酚明显降低EPSC2/EPSC1比率,也使I-V曲线左移,降低反转电位至-35mV左右。结论500μmol/L丙泊酚对大鼠海马CA1区兴奋性突触传递产生抑制作用,这可能与其增强突触前膜、突触后膜GABAA受体活性有关。     

异丙酚对皮质酮抑制体外培养大鼠海马神经前体细胞增殖的影响

目的 评价异丙酚对皮质酮抑制体外培养大鼠海马神经前体细胞增殖的影响及其与GABAA受体表达的关系。方法 体外培养大鼠海马神经前体细胞,第二代生长良好的细胞随机分为10组：空白对照组（Con组）、异丙酚0．5μmol/L组（P1组）、异丙酚2．5μmol/L组（P2组）、皮质酮100μmol/L组（Cort组）、荷包牡丹碱10μmol/L组（Bic组）、皮质酮和异丙酚0．5μmol/L组（CP1组）、皮质酮和异丙酚2．5μmol/L组（CP2组）、皮质酮、荷包牡丹碱和异丙酚0．5μmol/L组（BCP1组）、皮质酮、荷包牡丹碱和异丙酚2．5μmol/L组（BCP2组）、皮质酮和荷包牡丹碱组（BC组）。建立皮质酮抑制细胞增殖模型,利用噻唑蓝法和胸腺嘧啶核苷掺人法观察体外培养大鼠海马神经前体细胞的增殖。采用免疫细胞化学方法鉴定海马神经前体细胞GABAA受体的表达;采用ELISA法定量观察海马神经前体细胞表面GABAA受体表达。结果 异丙酚（0．5、2．5μmol/L）可以减轻皮质酮引起的大鼠海马神经前体细胞增殖的抑制作用,荷包牡丹碱可完全拮抗其作用。海马神经前体细胞有GABAA受体的表达,皮质酮100μmol/L可以使海马神经前体细胞GABAA受体表达下调（P＜0．05）,异丙酚可以阻断皮质酮的效应。结论 低浓度异丙酚可以减轻皮质酮引起的体外培养大鼠海马神经前体细胞增殖的抑制作用,可能与异丙酚激活GABAA受体有关。     

异丙酚对海马锥体神经元钠通道电流的抑制作用

目的 研究异丙酚对海马锥体神经元钠通道电流的影响,探讨脑钠通道在异丙酚麻醉中的作用。方法 酶消化法急性分离SD大鼠(10～14 d)海马锥体神经元,全细胞膜片钳技术记录异丙酚和脂肪乳剂对其钠通道电流的影响。结果 在钳制电位-100 mV时,4组浓度(10、30、50、100μmol/L)的异丙酚分别抑制峰钠电流为:14.4％±8.7％、42.9％±8.8％、67.2％±18.1％和85.1％±14.9％,抑制程度与浓度呈正相关(r=0.993,P<0.01),IC50为32.5 μmol/L。与本研究中较高浓度异丙酚组(50和100μmol/L)对应浓度的脂肪乳剂(ILP50组和ILP100组)对峰钠电流无明显影响。结论异丙酚对脑钠通道电流有明显的抑制作用,且呈剂量依赖性,提示脑钠通道的抑制在异丙酚的麻醉中可能起一定作用。     

异丙酚对N-甲基-D-天冬氨酸诱发大鼠海马神经元内游离钙离子浓度的影响

目的观察异丙酚对N-甲基-D-天冬氨酸（NMDA）诱发大鼠海马神经元内游离钙离子浓度（[Ca^2＋]i）的影响。方法取当天新生的Wistar大鼠海马神经元，培养12d随机分为5组，对照组（C组）、NMDA组、异丙酚10μmol／L＋NMDA组（P1组）、异丙酚100μmol／L＋NMDA组（P2组）、异丙酚400μmol／L＋NMDA组（P3组）。NMDA组培养液中加入NMDA至终浓度20μmol／L，P1组、P2组及P3组加入NMDA前即刻分别加入异丙酚至终浓度为10、100、400μmol／L，加入异丙酚后11min用激光共轭聚焦显微技术测定[Ca^2＋]。结果NMDA可诱发海马神经元[Ca^2＋]．升高，预先加入异丙酚100、400μmol／L可抑制这种改变，异丙酚10μmol／L对NDMA诱发的上述改变无影响。结论高浓度异丙酚可抑制NMDA诱发的大鼠海马神经元细胞[Ca^2＋]．的升高，这可能是其神经保护作用的机制之一。     

异丙酚对大鼠海马CA1缺血神经元持续钠电流的影响

目的 探讨异丙酚对大鼠海马CA1缺血神经元持续钠电流的影响。方法 酶消化法急性分离SD大鼠海马CA1锥体细胞,通过低氧和无糖法制备神经元缺血模型,全细胞膜片钳技术记录异丙酚对缺血神经元持续钠电流的影响。结果 神经元缺血5 min后持续钠电流显著增强。异丙酚10μmol/L和100μmol/L均能明显抑制缺血引起的持续钠电流增强(与0μmmol/L组比,P<0.01),此作用为异丙酚100μmol/L较10μmol/L儿更强(P<0.05)。结论 异丙酚能够抑制体外脑缺血时海马神经元持续钠电流,这可能是其产生脑保护作用的机制之一。     

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.