孕鼠产前缺氧性适应对新生大鼠的脑保护作用

目的研究产前缺氧性适应对新生大鼠脑组织是否具有保护作用.方法将临产前孕鼠(孕期22 d)12只随机分成2组,Ⅰ组为实验组(缺氧性适应组),Ⅱ组为对照组.Ⅰ组将孕鼠置于密封仓中,当氧浓度降至15%时,将孕鼠放入新鲜空气中5 min,再放入密封仓中,重复第一次过程,然后待其自然分娩.Ⅱ组除密封仓不密闭外(氧浓度21%),其余同Ⅰ组.将两组娩出的新生鼠分别随机取出40只,做新生鼠缺血缺氧性脑损伤模型,随机取两组的新生大鼠各30只于脑缺血缺氧后24 h处死,取脑组织分别进行光镜、电镜和流式细胞仪检测.结果Ⅰ组(缺氧性适应组)神经细胞多为正常,细胞排列较整齐,有少许早期凋亡细胞,凋亡率(2.9%±1.2%).Ⅱ组(对照组)神经细胞排列紊乱,部分细胞胞体肿胀,少部分呈空泡状,可见早期和中期凋亡细胞,少许晚期凋亡细胞和坏死细胞,凋亡率(9.51%±3.62%),凋亡率两组有统计学差异.结论孕鼠产前缺氧性适应可以明显降低新生鼠缺血缺氧性脑损伤程度,对新生大鼠脑组织具有明显的保护作用.     

孕鼠产前缺氧性适应后胎鼠、新生大鼠脑组织热休克蛋白70的表达

目的 通过观察产前缺氧性适应后胎鼠、新生大鼠组织热休克蛋白70（HSP70）变化,探讨产前缺氧性适应对胎鼠、新生鼠脑保护作用机制。方法 将临产前Wistar孕大白鼠22只随机分成2组,I组为实验组（缺氧性适应组）;将孕鼠置于缺氧性适应密封仓中,当氧浓度降至15%时,将孕鼠放入新鲜空气中5min,再放入密封仓中,重复第一次过程,然后待其自然分娩,Ⅱ组为对照组,除密封仓不密闭（氧浓度21%）外,其余同I组,两组于缺氧性适应（Ⅱ组模拟）后1、3、8、24、48、72、120、168h分别各取7只新生大鼠断头取脑,10%甲醛固定做海马冰冻切片,免疫组化染色评定HSP70免疫反应强度。结果 1、正常胎鼠、新生鼠脑组织中无HSP70表达;2、缺氧性适应后8hHSP70即有表达,可持续至168hh最强;3、在海马各区和皮层均有HSP70表达,但以海马CAl区最强。结论 热休克蛋白（HSP70）参与了产前缺氧性适应的形成。     

产前缺氧性适应后胎鼠、新生大鼠脑内凋亡相关基因bcl-2、bax mRNA的表达

目的：通过观察产前缺氧性适应后胎鼠，新生大鼠脑内bcl-2和bax基因mRNA变化，探讨前前缺氧性适应对胎鼠，新生鼠脑保护作用机制，方法：将临产前Wistar孕大白鼠24只随机分成2组，I组为实验组（缺氧性适应组），Ⅱ组为对照组，两组于缺氧性适应（II组模拟）后1，3，8，24，48，72，120，168h各取7只胎鼠或新生鼠断头取脑，分别做bcl-2,bax mRNA测定。结果：1．正常胎鼠，新生鼠脑组织中即有bcl-2和bax表达，从宫内22d到生后第7d,bcl-2,bax基因表达，及bcl-2/bax比值无明显变化，2．缺氧性适应后8h bax基因表达即有减少，24h降低最为明显，可持续至120h，缺氧性适应后24h bcl-2基因表达开始增加，可持续至72h;bcl-2/bax比值缺氧性适应后8h开始增加，24h达高峰，可持续至72h。结论：产前缺氧性适应后胎鼠，新生鼠脑组织bcl-2基因表达增加，bax基因表达减少，bcl-2/bax比值增加，此变化有时间依从性。     

PKC在缺氧预处理和去甲肾上腺素预处理减轻乳鼠心肌细胞缺氧复氧损伤中的作用

目的 评价蛋白激酶C(PKC)在缺氧预处理和去甲肾上腺素预处理减轻乳鼠心肌细胞缺氧复氧损伤中的作用.方法 原代培养乳鼠心肌细胞,随机分为6组(n=25):对照组(Ⅰ组)常规培养;缺氧复氧组(Ⅱ组)细胞缺氧3 h,复氧1 h;缺氧预处理组(Ⅲ组)缺氧20 min,复氧20 min后制备缺氧复氧模型;去甲肾上腺素预处理组(Ⅳ组)细胞经终浓度为10-7 mol/L去甲肾上腺素孵育30 min后,去除去甲肾上腺素,再行缺氧复氧;H7+缺氧预处理组(Ⅴ组)细胞经终浓度为5×10-5 mol/L的H7孵育10 min后,去除H7,其余操作同Ⅲ组;H7+去甲肾上腺素预处理组(Ⅵ组)细胞经终浓度为5×10-5 mol/L的H7(PKC活性抑制剂)孵育10 min后,去除H7,其余操作同Ⅳ组.复氧结束后,测定心肌细胞存活率、培养液乳酸脱氢酶(LDH)、肌酸激酶(CK)活性和心肌细胞MDA含量和SOD活性.结果 与Ⅰ组比较,Ⅱ组细胞存活率和SOD活性降低,LDH、CK的活性及MDA含量升高(P＜0.01).与Ⅱ组比较,Ⅲ组和Ⅳ组细胞存活率和SOD活性升高,LDH、CK活性及MDA含量降低(P＜0.01).与Ⅲ组比较,Ⅴ组细胞存活率和SOD活性降低,LDH、CK活性及MDA含量升高(P＜0.01).与Ⅳ组比较,Ⅵ组细胞存活率和SOD活性降低,LDH、CK活性及MDA含量升高(P＜0.05).结论 PKC激活参与了缺氧预处理与去甲肾上腺素预处理减轻乳鼠心肌细胞缺氧复氧损伤.     

异丙酚对新生大鼠离体延髓自发节律性呼吸放电的作用

目的 观察异丙酚对延髓基本呼吸节律中枢自发节律性呼吸放电的作用并探讨其可能的机制。方法 制备56只新生SD大鼠（0－3d）离体延髓－脊髓标本,改良的Krebs液（MKS）恒温灌流,随机分成Ⅰ～Ⅶ组（每组n=8)。I组为空白对照组（MKS组）,Ⅱ-Ⅵ组异丙酚浓度分别为5μmol/L、20μmol/L、50μmol/L、100μmol/L和250μmol/L持续灌流3min,第Ⅶ组先给GABAA受体特异性阻断剂荷包牡丹20μmol/L,然后异丙酚20μmol/L灌流3min,观察给药后1、3、5、10、15、30min时神经腹根自发节律性呼吸放电（SRRD)的活动。结果 1）I组各时间点SRRD各项指标均无显著性变化（P＞0．05）。2）Ⅱ-Ⅵ组与给药前比：给药后1－3minⅡ-Ⅴ组SRRD的频率增快、呼气时间缩短,5－10minⅡ-Ⅵ组SRRD频率随浓度增大显著减慢、呼气时间显著延长,第Ⅵ组15min时8只中有7只停止;Ⅱ-Ⅵ组SRRD的吸气时间无显著变化;SRRD放电强度（IAD）给药后3-5minⅡ组增强,Ⅲ-Ⅵ组减弱,10－15min时Ⅲ、Ⅳ组增强而第Ⅵ组减弱直至SRRD停止。3％荷包牡丹硷－异丙酚（BicPro) 组SRRD给药前后无显著变化。结论 1）异丙酚对新生大鼠离体延髓－脊髓标本SRRD具有浓度依赖性抑制作用,且以SRRD的呼气时间延长效应为主。2）GABAA受体在异丙酚对延髓基本呼吸节律中枢的抑制 作用中可能起重要作用。     

预吸氧对缺氧复氧大鼠脑诱导型一氧化氮合酶表达的影响

目的 探讨缺氧复氧大鼠脑诱导型一氧化氮合酶(iNOS)的表达及预吸氧的效应。方法 成年雄性Wistar大鼠72只,体重250-300 g,随机分为4组[对照组(Ⅰ)、较低浓度预吸氧组(Ⅱ)、高浓度预吸氧组(Ⅲ、Ⅳ)],每组又分成3个亚组(a、b、c)并做标记。Ⅰ a、Ⅱa、Ⅲa、Ⅳa组,分别吸入21％、50％、75％及95％O2 30 min;Ⅰ b、Ⅱb、Ⅲb、Ⅳb组,在预吸氧后分别给予5％O2缺氧20 min;Ⅰ c、Ⅱc、Ⅲc、Ⅳc组,在预吸氧、缺氧后,给予98％O2复氧20 min。各组动物均在实验结束后处死取脑组织,应用病理学方法和免疫组化技术观察损伤程度及iNOS的表达。结果 与预吸氧时相比,缺氧及复氧时iNOS表达增高(P<0.01);高浓度预吸氧组(Ⅲ、Ⅳ组)在缺氧及复氧时iNOS表达高于对照组(Ⅰ组)(JP<0.01);而较低浓度预吸氧组(Ⅱ组)iNOS表达低于对照组(Ⅰ组)(P<0.01),iNOS表达的程度与神经元损伤的严重程度相一致。结论 预吸高浓度的氧可诱导iNOS的表达,不利于脑缺氧性疾病的治疗,而低浓度预吸氧有利于脑组织保护。     

不同浓度舒芬太尼或芬太尼对硬膜外罗哌卡因分娩镇痛效应的影响

目的研究不同浓度舒芬太尼或芬太尼对硬膜外罗哌卡因分娩镇痛效应的影响。方法采用多中心、随机、双盲对照法进行该试验。初产妇224例，ASAⅠ级或Ⅱ级，妊娠≥36周，产前未服用镇痛、催眠药，随机分为7组：单纯罗哌卡因组（Ⅰ组，n=33）、罗哌卡因混合0．2μg／ml舒芬太尼组（Ⅱ组，n=33）、罗哌卡因混合0．4vg／ml舒芬太尼组（Ⅲ组，n=32）、罗哌卡因混合0．6μg／ml舒芬太尼组（Ⅳ组，n=31）、罗哌卡因混合1μg／ml芬太尼组（Ⅴ组，n=32）、罗哌卡因混合2μg／ml芬太尼组（Ⅵ组，n=31）及罗哌卡因混合3μg／ml芬太尼组（Ⅶ组，n=32）。所有产妇宫Vt开至2—3cm时，于L2，3间隙硬膜外穿刺头向置管，分别注人15ml罗哌卡因与不同浓度的舒芬太尼或芬太尼混合药液。各组初始的罗哌卡因浓度为0．12％，采用双盲、序贯法，以上一例产妇的镇痛效果确定下一例产妇所用的罗哌卡因药液浓度。采用视觉模拟评分法（VAS）评价注药30min内的疼痛程度，计算硬膜外罗哌卡因分娩镇痛的半数有效浓度（EC50），记录注药后30min产妇心率、收缩压及胎儿心率、运动阻滞程度及不良反应的发生情况。结果共有214例完成试验。硬膜外注药后30min内，产妇心率、收缩压及胎胎儿心率均在正常范围内，各组运动程度阻滞程度差异无统计学意义（P〉0．05）；与Ⅰ组比较，Ⅳ组和Ⅶ组不良反应发生率升高（P〈0．05）。各组硬膜外罗哌卡因分娩镇痛的EC50及其95％可信区间（95％CI）为：Ⅰ组0．1100％及0．1057％-0．1159％，Ⅱ组0．0741％及0．0708％．0.0789％，Ⅲ组0．0474％及0.0405％-0．0556％，Ⅳ组0．0355％及0．0289％-0．0438％，Ⅴ组0.0890％及0．0877％．0．0911％，Ⅵ组0．0730％及0．0717％-0．0744％，Ⅶ组0．0610％及0．0560％-0．0635％；Ⅱ-Ⅶ组EC50低于Ⅰ组（P〈0.05）；与Ⅱ组、Ⅵ组及Ⅶ组比较，Ⅲ组及Ⅳ组EC50降低（P〈0．05）。结论硬膜外混合舒芬太尼（0.2～0．6μg/ml）或芬太尼（1—3μg／ml）可增强罗哌卡因分娩镇痛效果；舒芬太尼的镇痛效应明显强于芬太尼；硬膜外混合罗哌卡因分娩镇痛中，舒芬太尼、芬太尼的推荐浓度分别为0．4μg／ml、2μg/ml.     

丙泊酚对儿童红细胞抗氧化酶系统的影响

目的观察不同浓度丙泊酚对儿童红细胞抗氧化损伤的保护作用。方法采集20例健康儿童动脉血制成压积红细胞．分为五种不同浓度丙泊酚组（12．5、25、50、75、100μmol／L）（Ⅰ～Ⅴ组）、单纯过氧化氢损伤组（Ⅵ组）和空白对照组（Ⅶ组）．孵育后测各组谷胱甘肽还原酶（GR）活力、谷胱甘肽（GSH）含量。结果Ⅵ组GR活力、GSH含量显著降低,丙泊酚浓度〈50μmol／L时,GSH含量、GR活性Ⅱ、Ⅲ、Ⅳ、Ⅴ组与Ⅵ组及Ⅶ组相比显著增加;当丙泊酚浓度〉50μmol／L时,GSH含量、GR活性皆呈下降趋势。结论一定浓度的丙泊酚可增强儿童红细胞谷胱甘肽抗氧化酶系统活性。     

利多卡因或丁卡因及其混合液大鼠硬膜外给药后药效的实验研究

大鼠１００只，在乙醚吸入全麻下经腰部置入硬膜外导管，分别注入５个递减浓度的利多卡因或丁卡因药液０。４ｍｌ（ｎ＝１０），测得下肢瘫痪率作列线图，求出利多卡因使下肢瘫痪ＥＤ５０为１。５２ｍｇ／只、丁卡因０。３２ｍｇ／只。大鼠７５只用于短效和长效局麻混合液试验，利多卡因按ＥＤ５０保持０。３８％浓度不变，丁卡因分别为０。０８％（Ⅲ组）、０。０６％（Ⅳ组）和０。０４％（Ⅴ组），对照分别按利多卡因ＥＤ５０为０     

硫化氢对大鼠海马神经元氧-糖缺失/恢复损伤的影响

目的研究硫化氢（H2S）对大鼠海马神经元氧-糖缺失/恢复损伤的影响。方法新生（24～48h内）Wistar大鼠断头,迅速取出海马,应用0．125%胰酶消化,海马神经元在96孔和6孔培养板上培养10d后随机分为5组：正常培养组（Ⅰ组）、氧-糖缺失/恢复组（Ⅱ组）、氧-糖缺失/恢复＋50μmol/L NaHS组（Ⅲ组）、氧-糖缺失/恢复＋100μmol/L NaHS组（Ⅳ组）和氧-糖缺失/恢复＋200μmol/L NaHS组（Ⅴ组）。Ⅱ组神经元进行氧-糖缺失45min后换回原来的培养液,然后放回原培养箱培养24 h,Ⅲ组、Ⅳ组和Ⅴ组在氧-糖缺失时加入NaHS,使其终浓度分别为50、100、200μmol/L,余处理同Ⅱ组,Ⅰ组按正常培养方法培养。检测96孔培养板神经元活力。鉴定6孔培养板的神经元纯度并进行细胞色素C水平、还原型谷胱甘肽（GSH）、丙二醛（MDA）浓度和神经元凋亡的检测。结果与Ⅰ组比较,Ⅱ组MDA浓度、细胞色素C水平和神经元凋亡率升高,GSH浓度和神经元活力降低（P＜0．05）；与Ⅱ组比较,Ⅲ组、Ⅳ组和Ⅴ组MDA浓度、细胞色素C水平和神经元凋亡率降低,GSH浓度和神经元活力升高（P＜0．05）；与Ⅲ组比较,Ⅳ组和Ⅴ组MDA浓度、细胞色素C水平和神经元凋亡率降低,GSH浓度和神经元活力升高（P＜0．05）；与Ⅳ组比较,Ⅴ组MDA浓度、细胞色素C水平和神经元凋亡率降低,GSH浓度和神经元活力升高（P＜0．05）。结论外源性H2S可减轻大鼠海马神经元氧-糖缺失/恢复损伤,其机制可能与其提高机体的抗氧化能力、减少神经元的凋亡有关。     

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.