肝移植术后免疫抑制剂的替换应用

目的 探讨和总结肝脏移植术后免疫抑制剂的替换应用情况和经验。方法 回顾性分析我院1993年4月－2001年7月施行的67例肝脏移植，对48例早期肝移植患者中发生的免疫抑制剂替换应用情况进行总结。结果 48例患者中，21例（43．8％）因术后出现排斥反应或严重毒副作用而替换为其它免疫抑制方案。环孢素A（CsA 硫唑嘌呤（Aza)＋激素方案组（31例）中，15例（48．4％）进行替换；CsA 霉酚酸酯（MMF）＋激素组（14例）中，6例（43％）进行替换。发生排斥反应者常规应用激素冲击治疗，同时替换免疫抑制剂，将CsA替换为他克莫司（FK506）或提高CsA剂量，可获得有效控制；出现药物性肝损害者应及时减少CsA用量或成FK506，其肝功能多能改善；出现肾功能损害者应减少CsA用量并改联用MMF，或替换成FK506后可有效挽救肾功能；白细胞减少或严重感染者，应停用Aza或MMF，或将CsA改为FK506后可有效挽救肾功能；白细胞减少或严重感染者，应停用Aza或MMF，或将CsA改为FK506；神经系统病变经更换免疫抑制剂可以好转。结论 合理应用免疫抑制剂是提高肝移植成功率的关键之一；治疗中应视具体情况及时、果断、合理地转换免疫抑制剂，可以有效控制排斥反应、毒副作用及相关并发症，提高移植肝的存活率。     

肝移植术后肝动脉狭窄的介入治疗和再移植时机

目的探讨肝移植术后肝动脉狭窄(HAS)的介入治疗效果和再次肝移植的时机。方法回顾性分析2 0例原位肝移植术后HAS患者的临床资料。所有病例经数字减影血管造影(DSA)确诊,均行血管内介入治疗。其中6例接受了再移植。介入治疗方法包括经皮腔内血管成形术(PTA)和支架植入术。结果早期HAS(移植后4周内)8例,介入治疗后肝功能好转6例,1例肝功能恶化及时再移植存活,另1例因肝衰竭死亡。1 2例晚期HAS中1例介入后于术后3 8 d死于严重感染和多器官衰竭;5例因肝功能反复异常、胆道缺血型狭窄和反复胆道感染而接受再移植,再移植围手术期死亡1例。2 0例平均随访13个月,2例分别因原发性肝癌和严重胆道感染死亡;3例出现肝动脉再狭窄并再次动脉内介入治疗成功。共出现缺血型胆道病变8例(4 0.0%)并行胆道介入治疗,5例肝功能改善。早期HAS和晚期HAS的1年和2年累计生存率分别为8 7.5%,4 3.8%和8 1.5%,5 4.3%,两组无统计学差异(P=0.9 7 6)。结论肝移植术后HAS未引起严重肝功能损害时,首选介入治疗,但缺血型胆道病变发生率较高。再次肝移植是治疗肝移植术后HAS导致不可逆性肝功能损害时的惟一有效手段     

肝移植术后迟发型急性排斥反应的发生和治疗

目的探讨肝移植术后迟发型急性排斥反应（lateacuterejection，LAR）的发生率、处理和预后。方法回顾性分析我科2004年8月至2006年8月收治的15例迟发型急性排斥反应（肝移植术6个月后发生的急性排斥反应）患者的临床资料。结果15例LAR发生在术后6．6—27个月，平均（14．7±7．5）个月。其中男14例，女1例。年龄32～66岁，平均年龄（49．5±12．7）岁。原发疾病为重症肝炎或肝功能衰竭者8例，占53．3％（8／15）；发生于血型不合移植者2例，免疫抑制治疗方案为单一普乐可复（FK506）治疗8例，单一环孢素A（CsA）治疗3例，已经停用激素13例，占86．7％。属于免疫抑制剂量不足者共10例，占66．7％。免疫抑制剂浓度正常范围者5例。按Banff分级标准排斥反应的程度为轻度者9例，中度6例，无重度排斥反应发生。治疗方法均首先加强或调整免疫抑制治疗，包括提高药物浓度、FK506／CsA转换、联合其他免疫抑制剂和激素冲击治疗，3例患者需长期口服激素。总的治愈率为80％，3例患者逐渐出现缺血型胆道病变，其中1例行再移植后死亡。结论迟发型急性排斥反应是肝移植术后常见但预后较好的并发症之一，免疫抑制不足是其发生的主要原因，及时地加强免疫抑制治疗可逆转排斥反应。     

再次肝移植治疗移植肝缺血型胆道损伤15例报告

目的探讨再次肝移植治疗缺血型胆道损伤的临床经验。方法回顾性分析15例因缺血型胆道损伤施行再次肝移植受者的临床资料。结果 15例移植受者术前均接受过介入治疗,再次肝移植全组无手术死亡。术后1个月存活率为67%,1年存活率为60%,3年存活率为53%。截止至2012年3月,有8例存活并返院随诊,存活时间超过5年的5例,其余3例存活时间分别为47个月、58个月、35个月,肝功能及生活情况良好。术后严重感染导致的多器官功能衰竭是再次肝移植患者死亡的主要原因。结论再次肝移植是治疗缺血型胆道损伤唯一有效的方法。对于缺血性胆道损伤,预防的意义远大于治疗。从供肝切取与保存、胆道重建、术后免疫抑制方案的选择、长期随访等等环节加以重视,有利于减少缺血型胆道损伤。     

再次肝移植临床分析

目的总结再次肝移植的病因、预后及手术方式。方法回顾性分析天津市第一中心医院1999年1月至2005年12月实施的101例再次肝移植的病因、术前MELD评分、与首次肝移植的时间间隔、手术术式选择、1年生存率、围手术期死亡的主要原因。结果再次肝移植1年的生存率为71．6％;再次移植的主要原因是胆道并发症（45、5％）;MELD值≤20的病例1年生存率（83．8％）明显高于MELD值为20—30和〉30的病例（57．1％和66．7％）;首次移植术后超过1个月再次移植围手术期生存率（83．8％）明显高于首次移植术后8—30d接受再次移植患者（41．7％）;围手术期死亡的主要原因是感染（54．2％）。结论选择合适的手术时机,根据术中情况决定具体术式,积极有效的抗感染治疗是提高再次肝移植生存率的关键。     

肾移植急性排斥后环孢素切换成他克莫司对移植肾的影响

目的 探讨肾移植术后急性排斥发生后环孢素（CsA）切换成他克莫司（FK506）抗排斥治疗对移植肾的影响。 方法 回顾性分析本中心肾移植患者发生病理证实的急性排斥86例,经过抗排斥治疗后有23例由CsA治疗切换成FK506为基础的免疫抑制治疗（FK506组）,63例继续应用CsA为基础的免疫抑制治疗（CsA组）。比较两组临床资料,包括性别、年龄、冷和热缺血时间、淋巴毒、术前群体反应性抗体（PRA）水平、人类白细胞抗原（HLA）错配、血脂、血清肌酐、血尿酸、再次排斥的发生率和移植肾存活等情况。 结果 抗排斥治疗后1年内再次病理证实的排斥率,FK506组显著低于CsA组[1/23（4.35%）比16/63（25.40%）,P = 0.033]。FK506组急性排斥发生后5年内的移植肾存活率为100%,高于CsA组的81.4%。FK506组急性排斥发生后24个月及36个月血尿酸分别为（265.5±147.9） μmol/L和（245.8±88.9） μmol/L,均显著低于CsA组的（428.5±119.3） μmol/L和（441.2±125.3） μmol/L（P < 0.01）。 结论 肾移植术后急性排斥发生后由CsA治疗切换成FK506治疗可降低再次排斥的发生率,而降低血尿酸水平有利移植肾的存活。     

心脏移植术后的免疫抑制治疗与排斥反应的监测

目的：探讨心脏移植术后排斥反应的监测指标及免疫抑制治疗效果,方法：对4例原位心脏移植患者术后给予他克莫司（FK506）,霉酚酸酯（MMF）及泼尼松组成的新三联进行免疫抑制治疗,同时进行急性排斥反应的监测,结果：死亡1例,存活3例,该3例未发生急性排斥反应,且生活质量良好,由FK506,MMF及泼尼松组成的新三联免疫抑制效果良好,结论：FK506,MMF及泼尼松的免疫抑制效果肯定,副作用少,排斥反应监测应把无创性检查与心内膜活检有机地结合起来。     

肝移植患者将他克莫司替换为环孢素A的临床分析

目的分析肝移植后需用环孢素A（CsA）替换他克莫司（FK506）的原因和结果。方法317例肝移植患者术后采用巴昔利单抗、FK506、霉酚酸酯及肾上腺皮质激素预防排斥反应，血FK506浓度谷值，术后0～30d维持在10～15μg／L，30-90d维持在8～12μg／L，90～180d维持在5～8μg／L。术后随访6个月。结果317例患者中，有16例（5．05％）需要将FK506替换为CsA，其中5例（31．25％）主要因为FK506的神经系统不良反应，2例（12．50％）因为血液系统不良反应，1例（6．25％）因为胃肠道不良反应，3例（18．75％）因血FK506浓度始终达不到治疗窗范围，2例（12．50％）因为顽固性高血糖，另有3例（18．75％）因为经济原因。除2例患者因药物替换后发生肾功能损害而再次恢复应用FK506方案外，其余14例患者的不良反应大多在替换为CsA后明显好转，无因换药而死亡的病例，也无与替换药物相关的不良反应。结论肝移植后，当发生FK506的不良反应时，将FK506替换为CsA是安全、有效的。     

肝硬化或肝癌伴银屑病患者肝移植术后治疗经验

目的总结患有银屑病的肝移植受者免疫抑制治疗的临床经验。方法以5例肝硬化或肝细胞癌(肝癌)伴银屑病的肝移植受者为研究对象,其乙型肝炎病毒(HBV)血清标志物均阳性。术前采用诱导方案,术后早期采用他克莫司(FK506)+吗替麦考酚酯(MMF)+肾上腺皮质激素(激素)三联免疫抑制方案,1周内停用激素。3例乙型病毒性肝炎(乙肝)后肝硬化合并肝癌肝移植患者1个月内逐步转换为西罗莫司替代治疗;2例乙肝后肝硬化肝移植受者患者一直采用FK506加或不加MMF方案。全部患者均予抗HBV治疗。分析其基本情况、银屑病皮损面积和严重性指数(PASI)评分变化及术后免疫抑制剂治疗方案的调整情况。结果 5例患者肝移植术后至投稿日随访(8.3±1.5)年,均存活。与术前相比,患者术后6个月PASI评分明显降低(P0.05)。2例乙肝后肝硬化肝移植受者患者在术后2年后出现银屑病复发,PASI评分显著升高,改为西罗莫司替代FK506的治疗方案后逐步下降,术后3年开始维持在稳定状态,无进展;3例乙肝后肝硬化合并肝癌肝移植受者无复发。结论以西罗莫司为主的免疫抑制治疗方案可有效控制肝移植受者的银屑病病情,对HBV阳性患者应同时进行抗HBV治疗。     

肝移植术后他克莫司所致的肝内胆汁淤积型肝损害六例

目的 探讨肝移植术后他克莫司所致的胆汁淤积型肝损害的临床特点与治疗方法.方法 6例肝移植患者术后采用他克莫司(FK506)、霉酚酸酯及泼尼松预防排斥反应.术后1～3个月出现丙氨酸转氨酶、天冬氨酸转氨酶、碱性磷酸酶、γ谷氨酰转移酶及胆汁酸水平升高,并伴有明显神经症状,影像学检查提示胆管吻合口通畅,胆管未见明显狭窄及扩张,也未发现移植肝动脉病变.移植肝组织活检提示肝内胆汁淤积、胆栓形成.停用或减量使用FK506,同时行内镜下胆管内引流(ERBD)、内镜下鼻胆管引流(ENBD)、经皮经肝穿刺胆道造影(PTC)及球囊胆道扩张术引流,并辅以护肝及抗炎治疗.结果 4例患者经ERBD或ENBD治疗,3个月后黄疸消退,血清转氨酶及胆管酶逐步恢复正常;1例经上述治疗3个月,未见明显好转,后行3次PTC及球囊胆道扩张术引流,于术后9个月血清转氨酶及胆管酶逐渐恢复正常,黄疸消退;1例上述治疗无效,接受再次肝移植.结论 肝移植术后他克莫司所致的胆汁淤积型肝损害一般发生在用药后1～4个月,应与移植肝缺血性胆道病变相鉴别,治疗方法主要是停用或减量使用他克莫司,早期行胆道引流术,保持胆道引流通畅,并辅以护肝、抗炎等治疗.     

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.