On-line血液透析滤过对维持性血液透析患者矿物质代谢的影响

目的 探讨On-line血液透析滤过技术对维持性血液透析患者矿物质代谢的影响.方法 选取尿毒症维持性血液透析患者110例,采用数字表法随机分为常规血液透析治疗组(HD组)和On-line血液透析滤过治疗组(HDF组),每组各55例.HD组患者每周行3次血液透析治疗,HDF组患者每周行2次常规血液透析治疗,1次血液透析滤过,时间均为4h.监测治疗当天和治疗3个月后患者外周血中血清钙离子、磷、全段甲状旁腺激素(iPTH)及碱性磷酸酶(ALP)等矿物质代谢的评估指标.结果 治疗前两组患者血钙、磷、iPTH及ALP水平差异无统计学意义(均P＞0.05).治疗3个月后,HD组血钙、iPTH和ALP与治疗前比较差异无统计学意义(均P＞0.05),血磷低于治疗前水平,与治疗前比较差异有统计学意义(P＜0.05).HDP组治疗后血磷、iPTH和ALP较治疗前下降明显(均P＜0.01).治疗后,HDF组血磷和ALP较HD组显著降低,差异有统计学意义(P＜0.05),iPTH降低更为显著(P＜0.01).结论 与普通血液透析比较,On-line血液透析滤过治疗能有效清除血磷,降低iPTH和ALP水平,从而改善维持性血液透析患者的矿物质代谢异常.     

不同血液净化方式对维持性血液透析患者矿物质及骨代谢异常的治疗效果

目的探讨3种血液净化方式联合骨化三醇注射液治疗尿毒症血液透析患者矿物质及骨代谢异常的差异。方法 60例维持性血液透析(MHD)患者,随机分为血液透析(HD)组、血液透析滤过(HDF)组、血液透析+血液灌流(HD+HP)组,每组患者20例,所有患者均使用骨化三醇注射液治疗,测定入选时及随访1个月和6个月后血钙、血磷、血甲状旁腺素(iPTH)。结果治疗前3组患者血清钙、磷、iPTH水平差异无统计学意义(P0.05)。治疗1个月及6个月后,患者血钙、血磷水平,3组间两两比较差异无统计学意义(P0.05)。3组患者血iPTH下降。HD组iPTH水平治疗1个月与治疗前比较差异无统计学意义(P0.05);治疗6个月与治疗前及治疗1个月比较,差异有统计学意义(P0.05)。HDF组和HD+HP组iPTH水平治疗1个月、6个月与治疗前比较明显下降,差异有统计学意义(P0.05)。HD+HP组iPTH水平治疗6个月和治疗1个月比较,差异有统计学意义(P0.05)。治疗6个月时,iPTH水平HD+HP组与HD组、HDF组比较,差异有统计学意义(P0.05)。结论对并发矿物质及骨代谢异常的维持性血液透析患者而言,血液透析滤过及血液透析+血液灌流联合骨化三醇注射液治疗更可有效控制矿物质及骨代谢异常,血液透析+血液灌流可以显著降低血iPTH和改善患者临床症状。     

在线血液透析滤过的临床疗效观察

目的 观察血液透析滤过(HDF)和血液透析(HD)对尿毒症患者不同溶质的清除和常见并发症的发生率.方法 45例规律透析患者前6个月行HD治疗为自身对照组.后6个月间歇行HDF治疗为实验组.对照组采用F6聚砜膜透析器,每周透析2～3次,每次4小时;实验组采用F60s聚砜膜透析器,每周透析2～3次,每次4小时,每2周HDF 1次.观察两组透析前后溶质:血尿素氮(Bun)、肌酐(Cr)、β2微球蛋白(β2-MG)清除及透析相关并发症的发生率.结果 两组透析前后Bun、Cr、均明显下降(P<0.01).HDF组透后β2-MG明显低于透前(P<0.01),HD组透析前后β2-MG差异无显著性(P>0.05).HDF组并发症的发生率较HD组明显降低(P<0.05).结论 HDF较HD能明显清除中分子物质,能明显降低透析相关并发症.     

联机血液透析滤过治疗尿毒症的临床应用研究

目的：探讨联机血液透析滤过（On-line hemodiafiltration,On-line HDF)对尿毒症患不同分子量物质的清除率、患耐受性及临床疗效。方法：回顾性分析18例伴有血透并发症及不适症状的尿毒症患行后稀释法On-line HDF 231例次，并与23例仍行常规血液透析（HD）治疗的患（887例次）进行比较，观察Kt/V，血清肌酐（Scr)、尿素氮（BUN）、血磷（SP）、β2－微球蛋白（β2－M）下降率及治疗中患血透常见并发症和不良反应发生率。结果：患对联机HDF治疗效果和耐受性显优于HD，透析并发症和不适症状发生率显低于HD（P＜0．01），联机HDF治疗后血清Scr、BUN、SP、β2－M水平显降低，KT／V明显增高。结论：后稀释法联机HDF能有效清除尿毒症患血中大、中、小分子物质，透析效果显提高，患对该法治疗的耐受性明显提高，适用于易出现血透并发症及不适症状的尿毒症患。     

碳酸镧联合不同血液净化方式对慢性肾脏病-矿物质和骨代谢异常患者钙磷代谢的影响

目的探讨碳酸镧联合不同血液净化方式对慢性肾脏病-矿物质和骨代谢异常(chronic kidney disease mineral and bone disorder,CKD-MBD)患者钙磷代谢的影响,为CKD-MBD患者选择最佳治疗方案,改善患者的生存质量。方法选择陕西省人民医院2014年1月至2015年5月行维持性血液透析的CKD-MBD患者76例,给予口服碳酸镧并按透析方式分为3组,血液透析(hemodialysis,HD)组24例、血液透析联合血液透析滤过(HD and hemodialysis filtration,HD+HDF)组27例,血液透析联合血液灌流(HD and blood perfusion,HD+HP)组25例,比较各组治疗前和治疗3个月后血钙、血磷、钙磷乘积及甲状旁腺素(parathyroid hormone,PTH)的变化。观察3组治疗中不良反应的发生率并进行比较。结果治疗3个月后,3组血钙较治疗前均升高,3组间血钙变化无统计学差异(P0.05);3组血磷及钙磷乘积较治疗前明显下降(P0.05),但HD+HDF组、HD+HP组较HD组下降更为明显(P0.05)。HD组门H在治疗前、后变化不大(P0.05),HD+HDF组和HD+HP组治疗3个月后PTH较前明显下降(P0.05)。HD组、HD+HDF组及HD+HP组患者并发症发生率分别为75.0%、18.5%、32.0%,HD组并发症明显高于HD+HDF组和HD+HP组,差异有统计学意义(P0.05),HD+HDF组并发症发生率最低。结论碳酸镧联合不同血液净化方式对血钙、血磷及PTH的清除效果不同,联合HDF和HP方式能明显清除血磷、PTH,改善钙磷代谢紊乱,不良反应小,适合临床应用治疗CKD-MBD。     

血液透析联合血液灌流治疗尿毒症患者周围神经病变的效果

目的 探讨血液灌流联合血液透析对尿毒症周围神经病变的疗效和机制.方法 将54例尿毒症周围神经病变的血液透析患者按数字表法随机分为血液灌流+血液透析组(HD+HP)和常规血液透析组(HD).HD+ HP组行每周连续3次HD+ HP治疗;常规血液透析组(HD)行每周3次常规HD治疗.治疗4周,比较治疗前后两组患者周围神经病变的临床症状、血PTH、β2-MG浓度和正中神经、胫神经、腓总神经的感觉神经传导速度(SCV)变化,分析PTH和β2-MG与SCV的相关性.结果 经过4周的治疗后,HD组患者周围神经病变的临床症状、血PTH、β2-MG、感觉神经传导速度无明显改善,而HD+HP组患者周围神经病变的临床症状、血PTH、β2-MG及SCV均较治疗前有明显改善,其程度显著优于HD组(P＜0.05),PTH和β2-MG与SCV有明显的相关性(P＜0.05).结论 连续短期HD+ HP能有效清除PTH和β2-MG,且对治疗尿毒症周围神经病变有效;PTH和β2-MG在体内蓄积与尿毒症周围神经病变有关.     

不同血液净化方式对慢性肾衰竭患者血清中分子毒素清除的比较

目的比较不同血液净化方式对慢性肾衰竭维持性血液透析（MHD）患者血清中不同分子质量毒素的清除效果。方法26例MHD患者,分别接受血液透析（HD）、血液灌流（HP）＋HD、血液透析滤过（HDF）三种方式进行血液净化治疗,所有患者均排除有影响生存质量的因素,均接受包括饮食控制、HD、促红细胞生成素和降压治疗。测定患者治疗前后血肌酐（SCr）、血尿素氮（BUN）及β2-微球蛋白（B,MG）、全段甲状旁腺素（iPTH）水平,同时计算其溶质清除率。结果HD、HP＋HD、HDF三种治疗方式的SCr和BUN清除率分别为（73．1±3．9）％、（71．7±3．1）％、（72．9±3.4）％和（76．5±4．9）％、（74．0±4．1）％、（77．4±4．3）％,三者比较差异无统计学意义。B2-MG及iPTH在HD中清除率很低,而在HP＋HD、HDF中β2-MG清除率分别为（32．8±6．5）％和（45．5±10．5）％,iPTH清除率分别为（43．8±8．9）％和（55．5±9．2）％,较HD显著升高,且两者治疗前后清除率比较差异均有统计学意义（P〈0．05）。结论三种血液净化方式对小分子溶质清除效果基本相似。HD对中、大分子溶质B2-MG、iPTH清除效果不明显,而HP＋HD及HDF能有效清除中、大分子溶质B2-MG、iPTH,其中HDF的清除率更高。     

血液灌流联合血液透析治疗尿毒症患者高β2-微球蛋白和高甲状旁腺激素临床观察

目的 观察血液灌流(hemoperfusion,HP)联合血液透析(hemodialysis,HD)在尿毒症患者治疗中,对血β2-微球蛋白(β2-MG)、全段甲状旁腺激素(I-PTH)清除效果及临床症状改善情况.方法 将血液灌流器与透析器串联作血液灌流-血液透析(hemoperfusion/hiemocIialysis,HP/HD)联合治疗,先行HP/HD2小时,树脂吸附达饱和后取下灌流器,继续HD 2小时,单次总治疗时间4小时,治疗前后各测1次β2-MG和I-PTH观察疗效.结果 β2-MG治疗前(37108.55±13570.59)μg/L,治疗后下降为32133.81±13785.98μg/L,iPTH治疗前(631.91±436.60)pg/mL,治疗后为(380.60±245.40)pg/mL,差异均有统计学意义.患者睡眠改善,食欲增加.结论 血液灌流对中大分子物质清除有效,长期应用可显著提高患者生活质量及生存率.     

胱抑素C下降率在终末期肾病患者中分子物质清除评估中的应用

目的 探讨胱抑素C下降率(cystatin Creductionratio,CyCRR)在终末期肾病(ESRD)患者中分子物质清除评估中的作用.方法 选择终末期肾病患者90例,按透析方式不同分为血液透析滤过(hemodiafitration,HDF)组和血液透析(hemodialysis,HD)组,每组各45例,于治疗前、后分别测定血清胱抑素C(CyC)、β2-微球蛋白(β2-MG)、全段甲状旁腺激素(iPTH)、瘦素(LP)、尿素氮(BUN)、肌酐(Cr)等指标,并根据上述指标计算胱抑素C下降率(CyCRR)、β2-微球蛋白下降率(β2-MGRR)、全段甲状旁腺激素下降率(iPTHRR)、瘦素下降率(LPRR)以及尿素清除指数(eKt/Vurea).对两组治疗前后血清CyC、β2-MG、iPTH、LP水平及下降率分别进行比较,同时对HDF组上述物质下降率进行相关性分析.结果 两组治疗前各项指标差异无统计学意义(P＞0.05).HDF组治疗后CyCRR 、β2-MGRR、iPTHRR、LPRR较HD组提高(P＜0.05),两组KT/V未见明显差异(P＞0.05).HDF组相关性分析显示,CyCRR不仅与β2-MGRR、iPFHRR、LPRR相关(P＜0.05),且与eKt/Vurea相关(P＜0.05).结论 HDF与HD相比较能有效提高CyC、β2-MG、iPTH、LP等中分子物质的清除率,而CyCRR可作为一种较准确反映终末期肾病患者中分子物质清除的评估指标.     

不同血液净化方式对血清β2-微球蛋白和甲状旁腺激素的影响

目的：探讨不同血液净化方式清除血清β2-微球蛋白（β2-MG）和甲状旁腺激素（iPTH）的效果。方法：将60例维持性血液透析患者分为3组：血液透析（HD）组、血液灌流＋血液透析（HP＋HD）组、高通量血液透析（HFHD）组,比较3组单次治疗对β2-MG和iPTH的清除率。结果：（1）HD组治疗前后血清β2-MG和iPTH均无显著下降（P〉0.05）,HP＋HD组治疗前后血清iPTH显著下降（P〈0.01）,β2-MG无显著变化（P〉0.05）,HFHD组治疗前后血清β2-MG和iPTH均显著下降（P〈0.01）;（2）HD组与HP＋HD组对血清β2-MG的清除率比较差异无统计学意义（P〉0.05）,此两组的清除率与HFHD组比较差异均有统计学意义（P〈0.01）;HFHD组与HP＋HD组对iPTH的清除率比较差异无统计学意义（P〉0.05）,此两组的清除率与HD组比较差异均有统计学意义（P〈0.01）。结论：HD不能有效清除β2-MG及iPTH;HP能有效清除iPTH,对β-MG无明显效果;HFHD能有效清除β-MG及iPTH。     

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.