卡托普利对家兔肾上腹主动脉阻断所致急性肾缺血／再灌注损伤的保护作用

目的 探讨卡托普利（CAP）对家兔肾上腹主动脉阻断致急性肾缺血/再灌注损伤（ARIRI）的保护效果。方法 于肾上阻断腹主动脉血流30min再灌注180min的方法制成双侧ARIRI动物模型,将24只家兔随机等分为假手术组（A组）、缺血再灌注组（B组）和CAP治疗组（C组）。C组于阻断主动脉前5min静注CAP2mg·kg^-1,继之持续输注15minCAP 0.5mg·kg^-1·h^-1。A、B组以等容生理盐水取代CAP。A组不阻断主动脉血流。动态检测血中BUN,Cr,SOD,MDA,AT-Ⅱ,尿β2-MG变化,以及肾皮质中SOD,MDA,AT-Ⅱ和肾组织形态学改变。结果 C组在再灌期血和肾皮质中MDA,AT-Ⅱ浓度明显低于B组（P<0.01)。SOD活性显著高于B组（P<0.01)。血BUN、Cr及尿中β2-MG含量明显低于B组（P<0.05,<0.01),C组光镜下肾小管损伤Paller评分明显低于B组（20.50±7.56vs82.50±16.69,P<0.05)。B组电镜见明显急性肾小管损伤及坏死,而C组肾小管损伤轻微。结论 CAP对家兔肾上腹主动脉阻断所致ARIRI有良好的保护作用。     

阿魏酸对家兔脊髓缺血再灌注损伤的防治作用

目的　研究阿魏酸对家兔肾下主动脉阻断所致脊髓损害的防治作用及其机理。方法家兔 2 4只 ,随机分为假手术组 (A组 ) ,缺血再灌注损伤组 (B组 )及阿魏酸组 (C组 ) ,每组 8只。B、C组肾下主动脉阻断 4 0分钟后开放 ,再灌注 7天。C组于阻断前 15分钟一次性静注阿魏酸 5 0mg/kg ,余两组则以同样方法静注等容量生理盐水作对照。测定阻断前 (C0 )、开放前 (C40 )、开放后 6 0分钟(R60 )及 7天 (R7d)血清中MDA、SOD、S10 0蛋白、TNFα、IL 1β的含量 ;术后观察后肢神经功能和脊髓形态学变化。结果　 (1)B组缺血及再灌注后血清MDA、S10 0蛋白、TNFα、IL 1β含量明显高于C0点及A组值 (P <0 0 1) ;C组明显低于B组 (P <0 0 1) ,与A组无显著性差异。 (2 )B组缺血及再灌注后SOD活力明显低于C0 点及A组值 (P <0 0 1) ;C组明显高于B组 (P <0 0 1) ,与A组无显著性差异。 (3)C组瘫痪发生率明显低于B组 (P <0 0 1) ,其后肢神经功能评分显著高于B组 (P <0 0 1)。 (4)B组脊髓病理变化较重 ,可见大量神经元坏死 ;C组偶有神经元坏死。结论　预防性静注阿魏酸对家兔主动脉阻断所致脊髓损害有良好的防治作用。其机理与阿魏酸抗氧化、抗炎及抑制TNFα、IL 1β水平升高有关     

丙泊酚对大鼠急性肾缺血再灌注损伤的影响

目的 探讨丙泊酚预处理对急性肾缺血再灌注损伤(acute renal ischemia reperfusion injury ,ARIRI)的保护作用及其机制.方法 采用完全随机研究设计(randomized controlled trial,RCT),健康近交系清洁级的雄性SD大鼠63只,随机分为3组:假手术组(A组)、缺血再灌注组(B组)、丙泊酚预处理组(C组),每组21只SD大鼠.采用切除右侧肾,用无损伤微动脉夹夹闭左侧肾蒂60分钟后解除阻断,建立大鼠急性肾缺血再灌注损伤模型.用24号套管针股静脉穿刺置管,实验过程中各组使用微量注射泵注入不同注射液.分别于手术前15分钟、再灌注后2小时、24小时留取血和肾组织标本同时处死大鼠,检测血清尿素氮(BUN)、肌酐(Cr)、超氧化物歧化酶(SOD)、丙二醛(MDA)、肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)及观察这三个时点肾组织的病理学改变.结果 丙泊酚预处理组各个时点的肾组织病理学变化均轻于缺血再灌注组.缺血再灌注组中血清BUN、Cr、MDA和TNF-α水平增加均高于丙泊酚预处理组(p＜0.05),丙泊酚预处理组血清SOD、IL-6水平均高于缺血再灌注组(p＜0.05).结论 丙泊酚预处理组血清BUN、Cr、MDA、TNF-α、SOD、IL-6水平与缺血再灌注组均有统计学差异.结果 表明丙泊酚能减少氧自由基释放,抑制和减少炎症反应,在急性肾缺血再灌注损伤能起到保护肾脏的作用.     

腹主动脉局部灌注丙泊酚减轻脊髓缺血-再灌注损伤的研究

目的 建立兔脊髓缺血-再灌注损伤模型,研究经腹主动脉局部灌注丙泊酚对脊髓缺血-再灌注损伤的作用。方法 新西兰大耳白兔30只,随机均分为A、B、C三组,诱导后气管插管,持续监测平均动脉压、心率、脉搏血氧饱和度及肛温。左股动脉切开置管至腹主动脉分出左肾动脉远端1．0cm处,于左肾动脉开口远端0．5cm处阻断腹主动脉,同时阻断双侧髂总动脉,自阻断即刻开始经置入导管分别向阻断的腹主动脉远端灌注5ml／kg丙泊酚溶液（A组）、10％脂肪乳（B组）和生理盐水（C组）,30min后开放。于动物完全清醒即刻、再灌注后6、24和48h对双后肢神经功能进行评分,光镜观察脊髓前角正常运动神经元并计数。结果 清醒即刻、再灌注后6、24和48hA组神经行为学评分明显高于B和C组（P〈0．05）,B、C两组比较差异无统计学意义。三组脊髓前角正常运动神经元中位数分别为11、1和0,A组明显高于B、C两组（P〈0．05）。结论 腹主动脉阻断期间经阻断的腹主动脉局部灌注丙泊酚可减轻脊髓缺血一再灌注损伤。     

丙泊酚在家兔肾下主动脉阻断术中对肾功能的保护作用

目的　探讨丙泊酚在肾下主动脉阻断术中对肾功能的保护作用及其机制。方法　 2 4只家兔随机分为假手术组 (A组 )、阻断组 (B组 )及丙泊酚 (C组 ) ,每组 8只。B、C组肾下主动脉阻断4 0分钟后再灌注 1小时 ,C组于阻断前 10分钟静注丙泊酚 5mg/kg ,继以持续输注丙泊酚 2 0mg·kg-1·h-1至松开前 5分钟 ;余两组以等容量生理盐水作对照。测定给药前 (C-10 )、松开前 (C40 )、松开后 1小时 (R60 )血中内皮素 1(ET 1)水平及尿素氮 (BUN)、肌酐 (Cr)、K+ 、Ca2 + 含量 ,记录阻断前、阻断后、松开后尿量并测定尿 β2 微球蛋白 (β2 MG)含量。结果　 (1)B组再灌注后血浆ET 1水平明显高于阻断前及A组 (P <0 0 5 ) ,C组阻断后及松开后血ET 1较阻断前无明显变化。 (2 )B组R60 时的血浆BUN、血K+ 含量明显高于基础水平 (P <0 0 5 ) ,C组无明显变化。 (3)B组及C组阻断后尿量均明显升高 ,再灌注后B组尿量明显低于阻断前 (P <0 0 5 ) ,B组尿 β2 MG明显高于阻断前及C组 (P <0 0 5 )。结论　肾下主动脉阻断可导致肾小球及肾小管功能障碍。丙泊酚对肾功能有保护作用 ,其机制与其抑制ET 1水平升高有关     

丙泊酚对大鼠肾缺血-再灌注期血清白细胞介素-8的影响

目的观察丙泊酚对大鼠肾缺血-再灌注期血清白细胞介素-8(IL-8)的合成和释放的影响,并探讨其肾保护机制。方法选用12~14周雄性大鼠75只,随机分为三组,每组25只,以无创动脉夹夹闭双侧肾蒂60min制备急性肾缺血-再灌注模型。A组为肾缺血-再灌注组,B组为丙泊酚处理组,C组为假手术组。各组设立五个时间观察点:缺血前10min(T0),缺血60min(T1),再灌注1h(T2)、3h(T3)、6h(T4),每个时间点5只大鼠。C组:肾脏缺血60min,缺血前5min从股静脉注射丙泊酚20mg/kg,继之经微量泵持续输入丙泊酚(0·5mg/ml)50mg·kg-1·h-1,持续60min;A、B组以等容生理盐水取代丙泊酚,但A组不夹闭双侧肾蒂,术中保持大鼠呼吸、循环稳定。各组大鼠存活至预定时间后再次麻醉取标本,测定血浆丙二醛(MDA)、超氧化物歧化酶(SOD)、血清IL-8,同时用光学显微镜观察肾组织形态学改变及肾小管损伤情况。结果血浆MDA在C组T1~T4时无明显变化,同A组相似,较B组相应时点显著降低,而B组T1~T4时较T0时及A组各时点显著升高;SOD则呈相反变化;C组T1~T3时血清IL-8无明显变化,仅在T4时较T0时和A组有显著升高,而B组在T1~T4时分别增加1·73、2·50、2·76、2·89倍,同C组和A组相比有显著性差异;光镜下观察发现B组肾小管上皮细胞变性、坏死,细胞脱落,肾小管管腔变窄,肾间质水肿、充血伴炎性细胞浸润明显;而C组以肾小管肿涨为主,个别呈坏死样改变,肾间质水肿、充血、炎性细胞浸润不明显。结论丙泊酚除了有抗氧作用外,还能有效地抑制血清IL-8合成和释放,这可能是丙泊酚减轻肾缺血-再灌注损伤的机制之一。     

红景天甙对大鼠肾脏缺血再灌注损伤的保护作用

目的探讨红景天甙对大鼠肾脏缺血再灌注损伤（IRI）的预防和保护作用。方法将32只健康成年SD大鼠随机分成正常对照组、假手术组、缺血再灌注组和红景天甙组4组，每组8只。缺血再灌注组和红景天甙组分别制作肾脏缺血再灌注模型，红景天甙组予以红景天甙预处理。检测血中尿素氮（BUN）和肌酐（Scr）及肾脏中超氧化物歧化酶（SOD）、丙二酰二醛（MDA）和钠钾ATP酶（Na^＋-K^＋ATPase）含量，并用光镜和电镜观察肾脏组织形态学变化。结果红景天甙组血清BUN和Scr水平、肾皮质MDA含量较缺血再灌注组显著降低（P〈0．01），而肾皮质中SOD和Na^＋-K^＋ATPase含量与缺血再灌注组相比显著升高（P〈0．01）；肾组织光镜和电镜观察均见缺血再灌注组肾小球和肾小管上皮细胞损伤明显，而红景天甙组肾小球及肾小管仅见轻微损伤。结论红景天甙能有效降低大鼠肾脏缺血再灌注损伤（IRI），对肾脏IRI有明显的预防和保护作用，为临床上肾脏IRI提供新的预防和治疗思路。     

钙离子和钙通道阻滞剂在大鼠腹部多器官缺血再灌注损伤中作用的实验研究

细胞内钙离子平衡失调是组织缺血再灌注损伤的重要因素之一,腹部多器官联合移植过程中发生了比单一器官更为严重的缺血再灌注损伤,但未见报道钙离子在腹部多器官缺血再灌注损伤中的作用。 本研究旨在建立大鼠腹部多器官同时缺血再灌注模型,通过分析组织钙离子和组织丙二醛(MDA)含量、血清生化改变和电镜组化细胞内钙离子定位技术来研究钙离子在该模型中的作用以及钙通道阻滞剂异搏定对缺血再灌注损伤的影响,为钙通道阻滞剂在器官的保存和腹部多器官移植过程中的临床应用提供理论依据。 在大鼠腹腔干平面上阻断腹主动脉30分钟以造成腹部多器官同时缺血,行远端腹主动脉和下腔静脉插管。经腹主动脉灌洗腹部器官,下腔静脉插管作为流出道,然后放开血管夹,再灌注120分钟。动物分为手术组(S组),生理盐水对照组(C组),异搏定组(V组)。 观察到缺血期末,C组和V组大鼠的肝、小肠、胰腺组织的钙离子含量、MDA含量、血清ALT、LDH、AMY水平与S组比较,仅有轻度升高(P>0.05),电镜下发现缺血时的肝细胞内细胞器无明显钙离子沉积;但是再灌注后C组和V组血清酶水平、组织钙离子含量和MDA含量与缺血期末和S组比均有显著性升高(P<0.01),组织钙离子含量和MDA含量呈正相关关系;C组随着再灌注时间的延长上述指标逐渐升高,在观察时     

抑肽酶在肠缺血-再灌注中对肝脏的保护作用

目的应用肠系膜上动脉阻断(SMAO)模型,观察抑肽酶在肠缺血-再灌注损伤过程中对肝脏的保护作用。方法24只日本大耳白兔随机平均分为:假手术组(A组),肠系膜上动脉(SMA)不作阻断;缺血-再灌注组(B组);抑肽酶治疗组(C组)。B、C两组采用家兔SMAO模型,阻断时间为45min。C组阻断前5min静注抑肽酶30000kIU/kg,随后以10000kIU·kg-1·h-1维持至实验结束。B、C两组在阻断前(I0)、阻断45min(I1)、再灌注1h(R1)、再灌注2h(R2)时观察血清丙二醛(MDA)、过氧化物歧化酶(SOD)、肿瘤坏死因子α(TNF-α)、磷脂酶A2(PLA2)及肝脏组织形态学变化。A组在相应时点取样检测上述指标。结果(1)C组MDA、TNF-α、PLA2在R2时均明显低于B组(P<0·05),而B组明显高于A组(P<0·05)。(2)C组SOD在R2时明显高于B组(P<0·05)。结论抑肽酶减轻脂质过氧化反应,对肠缺血-再灌注损伤有一定保护作用。血清PLA2和TNF-α的产生和释放减少,可能减轻肠缺血-再灌注过程中对远隔离器官的损害,对肝脏有一定的保护作用。     

卡托普利在家兔主动脉阻断手术中对对脊髓损伤的保护作用

目的研究卡托普利在家兔肾上主动脉阻断手术中对脊髓损伤的保护作用及其机理.方法家兔24只,随机分为假手术组(A组)、缺血组(B组)和卡托普利组(C组).肾上阻断腹主动脉30min后松开,C组于阻断前10min静注卡托普利0.5mg@kg-1,继以0.15mg@kg-1@h-1持续输注至松开前10min.连续监测颈总动脉(BPi)和股动脉(BP2)平均动脉压,记录阻断前10min、阻断后5min、20min、30min以及松开后5min、60min、180min的BP1和BP2值,松开后3h观察胸10和腰3水平脊髓形态学变化,并测定脊髓组织丙二醛(MDA)含量.结果①B组动物阻断后的BP1显著高于阻断前(P＜0.05或0.01),C组阻断后BP1较阻断前无显著变化;B组松开后5、60、180min的血压均明显低于阻断前,C组松开后60、180min的血压比B组明显升高(P＜0.05).②B组脊髓MDA含量明显高于A组(P＜0.01),C组与A组无显著性差异,但明显低于B组(P＜0.05).③B组脊髓病理变化较重,可见大量神经元坏死,C组偶有神经元坏死.结论在家兔肾上主动脉阻断手术中使用卡托普利对脊髓损伤有较好保护作用,其机制与抗过氧化反应及缓解血液动力学波动有关.     

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.     

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.     

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.