雷公藤多甙联合生长抑素治疗对大鼠急性坏死性胰腺炎肠道细菌移位的影响

目的 探讨雷公藤多甙联合生长抑素治疗对大鼠急性坏死性胰腺炎(ANP)肠道细菌移位的影响. 方法 逆行胰胆管穿刺注射3.5%牛磺胆酸钠(0.2 ml/100 g)诱导ANP大鼠模型.分为5组:假手术组(SO)、坏死组(ANP)、生长抑素治疗组(ANP+S)、雷公藤多甙治疗组(ANP+T)、雷公藤多甙+生长抑素治疗组(ANP+T+S).术后禁食12 h,不禁水.各组均随机标记6只观察术后生存时间.术后24h,观察血清淀粉酶、血清脂肪酶活性,血浆内毒素水平,脏器细菌培养结果,胰腺和回肠黏膜病理学变化及大鼠存活率. 结果 雷公藤多甙与生长抑素联合治疗ANP大鼠,可以显著降低血清淀粉酶、血清脂肪酶活性;减轻胰腺组织和肠黏膜炎症细胞浸润、水肿;降低血浆内毒素水平和脏器细菌培养阳性率;提高ANP大鼠存活率. 结论 ANP大鼠存在肠道细菌移位;雷公藤多甙联合生长抑素的治疗可减轻ANP大鼠胰腺和肠道损伤,加强肠道的生物学屏障,降低肠源性细菌及内毒素移位发生率,阻止ANP的发展.     

急性坏死性胰腺炎时肠屏障损害及肠源性细菌和内毒素移位的实验研究

目的 观察急性坏死性胰腺炎（ANP）时肠粘膜屏障的改变和肠源性细菌和内毒素移位。方法 将Wistar大鼠随机分为正常对照组（n=6)、假手术组（n=30)和ANP组（n=39)。采用人工胆汁胰管逆行灌注法制作ANP模型。观察胰腺、小肠病理改变和小肠粘膜上皮细胞间紧密连接（冷冻蚀刻电镜）变化。动态测定血浆D-乳酸、内毒素水平,以及腹腔脏器细菌移位率。结果 ANP后小肠粘膜损伤,皮皮细胞间紧密连接破坏甚至消失,血浆D-乳酸水平上升,发病早期即出现内毒素血症;ANP发生后72h脏器细菌移位率达到59.5%。结论 ANP早期肠粘膜屏障功能受损。导致肠道细菌和内毒素移位,成为全身炎症反应和胰腺继发感染的根源。     

急性胰腺炎肠道屏障功能损伤时血浆内毒素和D-乳酸的变化

目的 探讨急性胰腺炎肠道功能损伤时内毒素和D-乳酸的变化.方法 Wistar大鼠随机分为假手术(SO)组和重症急性胰腺炎(SAP)组.术后分4个时段心脏抽血处死,取胰腺组织和回肠组织行组织学检查.偶氮显色法测定血浆内毒素;改良分光光度法测定血浆D-乳酸.结果 SAP组血浆内毒素和D-乳酸随发病时间的延长而持续升高,SO组血浆内毒素和D-乳酸随时间的延长无明显变化.两组比较差异显著(P<0.05).内毒素与D-乳酸呈正相关.(r=0.7323,P<0.05).结论 内毒素和D-乳酸在SAP肠道损伤时升高,可作为评价肠道屏障功能的指标.     

选择性肠道去污染对肝硬化大鼠肝门阻断细菌移位、内毒素血症的影响

目的探讨选择性肠道去污染对肝硬化大鼠肝门阻断后肠道细菌移位、内毒素血症的效果。方法将制成肝硬化模型的60只雄性SD大鼠随机分为假手术组、肝门阻断30rain组（阻断组）及通过选择性肠道去污染预处理组（预处理组）,各20只。在实验术后30min及24h时分别取肠系膜淋巴结、肝、肺及门、腔静脉血作细菌培养,并取门、腔静脉血作内毒素检测。结果阻断组大鼠手术后30min即出现门、腔静脉血内毒素浓度升高（P〈0．01）,在手术24h后升高更明显。并在术后24h肠系膜淋巴结、肝组织及门、腔静脉血细菌培养出现阳性,主要为大肠杆菌。预处理组大鼠无论是手术30min还是24h后,门、腔静脉内毒素水平升高均不明显,较阻断组明显降低（P〈0．01）,肠道外组织及门、腔静脉血细菌培养阳性率也明显降低。结论肝硬化大鼠肝门阻断30min后早期即可出现内毒素血症,并于手术24h后出现明显肠道细菌移位。选择性肠道去污染能减少肝硬化大鼠肝门阻断后肠道细菌移位及内毒素血症的发生。     

肿瘤坏死因子对急性坏死性胰腺炎肠道屏障的影响及生长抑素的作用

目的 探讨肿瘤坏死因子（TNFα）在急性坏死性胰腺炎（ANP）肠道损伤中的作用及生长抑素对其肠道的保护作用。方法 制成大ANP模型,分为假手术组、ANP组及生长抑素治疗组。分别于术后6、12、24、48h测定血浆TNFα、内毒素、淀粉酶,并观察胰腺和回肠粘膜病理学及电镜超微结构及肠道细菌移位情况。结果ANP组血浆TNFα、内毒素、淀粉酶水平显著高于假手术组和治疗组,且以发病后12、24h最为明显（P<0.01-0.05）,血中细菌和肠系膜淋巴结（MLN）细菌移位率均为100％;肠粘膜上皮坏死脱落、血管扩张充血,固有膜中度水肿伴有炎性细胞浸润,电镜观察肠粘膜微绒毛长短不一、排列不整齐,脱落严重。生长抑素（SS）治疗组血浆 TNFα、内毒素、淀粉酶水平显著高于假手术组,也以发病后12、24h最为明显（P<0.01-0.05）,血中细菌和MLN细菌移位率为60％,光镜及电镜下肠粘膜也有明显病损,但程度较ANP组明显减轻。结论TNFα是导致ANP时肠道屏障损伤的重要因素,生长抑素能减轻ANP时肠道屏障的损伤。     

微生物酵素对抗生素相关性肠黏膜屏障损伤大鼠的保护作用

目的观察应用微生物酵素对大鼠抗生素（克林霉素磷酸酯）相关性肠黏膜屏障损伤的保护作用。方法制备大鼠抗生素相关性腹泻模型,分别对抗生素相关性腹泻组与微生物酵素喂养组模型的下腔静脉血行D-乳酸和二胺氧化酶（DAO）测定、细菌培养以及肝脏组织和肠系膜淋巴结行组织细菌培养、回肠内容物菌群培养、回肠末端行病理检查并评分,将两组数据进行统计学分析。结果与单用抗生素组相比,微生物酵素喂养组大鼠于第7天时血浆中DAO和D-乳酸水平显著降低（P〈0.05）,肠内容物中大肠埃希菌（7d,P〈0.01）和肠球菌（7d,P〈0.05）显著减少,乳酸杆菌（5d,P〈0.05;7d,P〈0.01）和双歧杆菌（5d、7d,P〈0.01）显著增多,7d时肝脏和肠系膜淋巴结的培养阳性率显著降低（P〈0.05）,下腔静脉血细菌培养阳性率无显著差异,7d时回肠病理评分显著降低（P〈0.01）。结论应用抗生素（克林霉素磷酸酯）可以造成肠道菌群紊乱及肠黏膜屏障损害,导致肠道黏膜上皮通透性升高,菌群易位以及肠外器官的损伤。加用微生物酵素可加强肠黏膜屏障,降低肠道的通透性,减少菌群易位,预防肠源性感染的发生。     

枳术汤加味对大鼠肠黏膜屏障功能的保护作用

目的 探讨中药枳术汤加味对大鼠肠黏膜屏障功能的保护作用及其机制.方法 将70只雄性大白鼠随机分为对照组(10只)、造模组(20只)术前连续7d饮水灌胃0.35ml/次,每天2次,治疗组(20只)术前连续7d中药灌胃0.35ml/次,每天2次,大剂量治疗组(20只)术前连续7d中药灌胃0.7ml/次,每天2次.大鼠按2.5ml/kg体重的剂量给予腹腔内注射5%水合氯醛进行麻醉.进腹后血管钳夹闭肠系膜上动脉,持续30min后恢复血供,使肠道发生缺血-再灌注损伤.分别在再灌注1、24h后进行以下检测:肠道细菌移位发生率;回肠黏膜病理变化;外周血浆D-乳酸浓度、二胺氧化酶浓度;回肠黏膜细胞凋亡指数.结果 缺血-再灌注1、24h后细菌移位阳性率、细菌培养阳性率和血浆D-乳酸和二胺氧化酶浓度,造模组高于对照组(P<0.05);治疗组低于造模组(P<0.05);大剂量治疗组和治疗组比较差异无统计学意义(P>0.05). 回肠膜黏重量、绒毛高度及宽度,造模组小于对照组(P<0.05);治疗组大于造模组(P<0.05);大剂量治疗组和治疗组比较差异无统计学意义.肠黏膜上皮细胞凋亡指数,造模组高于对照组(P<0.05);治疗组低于造模组(P<0.05);大剂量治疗组和治疗组比较差异无统计学意义(P>0.05). 结论中药枳术汤加味能减少肠道细菌移位,降低肠黏膜的通透性,可以保护肠黏膜屏障功能.     

生长抑素对大鼠坏死性胰腺炎GH-IGF-1-白蛋白轴的影响及其对肠黏膜屏障的保护作用

目的:研究生长抑素(somatostatin,S)对坏死性胰腺炎(acute necrotizing pancreatitis,ANP)肠黏膜屏障损害的治疗作用.方法: 逆行胰胆管注射3.5%牛磺胆酸钠(0.2 ml/100 g)诱导ANP模型.分四组,分别为正常( N)组、假手术(SO)组、坏死(ANP)组和治疗(ANP+S)组.术后24 h抽血测血浆D-乳酸、血清G H、胰岛素样生长因子(IGF-1)和白蛋白浓度,取末端回肠观察并计算绒毛高度和黏膜厚度变化. 结果ANP组回肠通透性上升,绒毛高度和黏膜厚度减小,血清白蛋白、GH和IGF-1均下降.生长抑素治疗后可减轻ANP鼠肠黏膜厚度及绒毛的改变,降低肠道通透性,血清GH、白蛋白浓度较ANP组为高,IGF-1两组无显著性差异. 结论外源性生长抑素对ANP鼠肠黏膜屏障有保护作用.     

HMGB1对急性坏死性胰腺炎大鼠肠上皮细胞紧密连接相关蛋白表达的影响

目的：观察急性坏死性胰腺炎（ANP）大鼠肠黏膜中高迁移率族蛋白B1（HMG81）的表达对肠黏膜上皮细胞紧密连接功能的影响。方法：24只Wistar大鼠随机分为正常对9帚组、ANP组和丙酮酸乙酯（EP）处理组,分别于建模后24h取材。测定血浆淀粉酶（AMY）、血浆D-乳酸、肠黏膜髓过氧化物酶（MPO）水平变化;应用Westernblot法检测ANP大鼠肠黏膜中HMGBl和occludin蛋白水平的变化。结果：在建模后24h,大鼠AMY、D-乳酸与肠黏膜MPO水平ANP组明显高于正常对照组和EP处理组（P〈0．05）,但EP处理组仍高于正常对照组（P〈0．05）;ANP组大鼠肠黏膜HMGBl表达水平明显高于正常对照组和EP处理组（P〈005）,EP处理组高于正常对照组（P〈0．05）;而肠黏膜上皮细胞紧密连接蛋白occludin的表达ANP组较正常对照组和EP处理组下降（P〈0．05）,EP处理组低于正常对照组（P〈0．05）。结论：ANP大鼠肠黏膜中HMGBl表达增高,可通过降低occludin蛋白表达,增加肠黏膜屏障通透性。EP能显著抑制HMGBl表达,使occludin蛋白表达升高,对ANP肠黏膜损伤有明显保护作用。     

阻塞性黄疸大鼠肠黏膜屏障功能变化及力肽的治疗作用

目的探讨阻塞性黄疸大鼠肠黏膜屏障功能变化以及力肽的治疗作用。方法将36只Wistar大鼠随机分成胆管结扎组（BDL）、假性手术组（SL）、胆管结扎＋力肽治疗组（Dipeptiven）3组，分别于术后24h、72h、1周和2周测定血浆内毒素值（Endotoxin，ET），并于2周后作细菌移位率和肠黏膜组织学检查。结果BDL组厌氧菌移位阳性率（58．33％）及各时间点血浆ET值显著高于SL组（0）和Dipeptiven组（8．33％）（P〈0．01），Dipeptiven组在各时间点血浆ET值较BDL组显著降低（P〈0．01）。组织学检查显示，BDL组肠黏膜发生了实质性损害。结论阻塞性黄疸时肠黏膜屏障损害可能促进肠道细菌移位，导致感染易感性增高。而力肽可改善受损小肠黏膜结构及减轻肠道细菌移位。     

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.     

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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.     

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.