前后路一期病灶清除植骨内固定治疗腰骶脊柱结核

目的探讨采用前后路一期病灶清除植骨内固定治疗腰骶脊柱结核的临床效果。方法采用后路椎弓根内固定加前路病灶清除植骨治疗腰骶椎结核10例，术后抗痨治疗。结果切口均一期愈合，无窦道形成。随访1-4年，植骨块均在4—6个月融合，无植骨块松动移位发生，所有患者腰痛、下肢麻痛症状消失。结论采用后路椎弓根内固定加前路病灶清除植骨是治疗腰骶椎结核的一种稳定可靠的手术方法。     

一期后路病灶清除植骨融合内固定治疗腰骶椎结核

目的 探讨一期后路病灶清除植骨融合内固定治疗腰骶椎结核的可行性及临床疗效.方法 21例腰骶椎结核患者经正规抗结核治疗2～4周,行一期后路病灶清除植骨融合内固定术,联合术后规范化抗结核治疗12～18个月.结果 手术时间150～240(180±32)min;术中出血量400～800(600±84)ml;术中无神经、硬膜、大血管损伤.术后1例切口出现窦道形成二期愈合,其余切口均一期愈合.患者均获随访,时间24～54(36.5±2.3)个月.术后1年均植骨融合.末次随访时腰骶角为24.5°±5.3°;患者脊柱结核均治愈,无复发;8例神经功能障碍者均恢复至Frankel E级.结论 在规范化抗结核治疗基础上行一期后路病灶清除植骨融合内固定治疗腰骶椎结核安全、有效,但应严格掌握适应证.     

一期后路短节段固定并病灶旷置术治疗老年腰骶椎结核

目的评价一期后路短节段固定并病灶旷置术治疗老年腰骶椎结核的疗效。方法 2007年1月—2013年12月共收治48例老年腰骶椎结核患者,均采用一期后路钉棒系统短节段内固定联合腰骶椎病灶旷置(将链霉素粉剂填塞入"开窗的椎间隙"之间)治疗。记录手术时间、出血量、植骨融合时间及手术并发症。采用疼痛视觉模拟量表(VAS)评分、Oswestry功能障碍指数(ODI)和美国脊髓损伤协会(ASIA)神经功能分级评估手术疗效。结果所有患者随访28~86个月,平均63个月。手术时间(139.5±51.8)min,出血量(220.8±71.5)m L,植骨融合时间(4.5±1.7)个月,末次随访时植骨均获得骨性融合。除3例ASIA神经功能分级为D级的患者神经功能无变化外,其余有神经损伤患者均恢复至E级。患者均未出现大血管、神经损伤及伤口深部感染。术后1例患者由于疼痛复发而二期再行椎板减压病灶清除内固定;1例患者发生皮神经痛,给予非甾体镇痛药物塞来昔布口服,随访时患者疼痛消失。结论对于伴有神经症状或顽固性疼痛,但不伴有脓肿和死骨的腰骶椎结核患者行一期后路短节段固定结合病灶旷置术抗结核药物治疗效果好,能同时获得缓解腰骶部疼痛、神经根减压、维持稳定及融合的效果,但应注意严格掌握手术指征。     

一期后路病灶清除植骨融合内固定治疗腰骶椎结核

目的探讨一期后路病灶清除植骨融合内固定治疗腰骶椎结核的临床疗效。方法对15例腰骶椎结核患者采用一期后路病灶清除、植骨融合、腰椎椎弓根钉和骶骨椎弓根钉或侧翼钉内固定治疗。结果手术时间平均为170.5 min±24.2 min,术中出血量平均为980.3 ml±168.6 ml。无硬脊膜和大血管损伤,无窦道形成等。患者均获随访,时间12~39个月,均获得骨性融合,无内固定松脱。按骨结核治愈标准评价:患者全部治愈,无结核复发迹象。11例术前下肢肌力不同程度减退,末次随访时除1例趾伸肌力由Ⅲ级恢复至Ⅳ级外,其余全部恢复至Ⅴ级;11例术前小腿或足皮肤痛触觉减退,末次随访时除2例部分恢复外,其余全部恢复正常;术前膝、踝反射减弱或消失9例,末次随访时2例部分恢复,其余全部恢复正常;术前6例直腿抬高试验60°内阳性,术后全部恢复正常。结论在正规抗结核治疗基础上,一期行后路病灶清除植骨融合内固定治疗腰骶椎结核是一种安全有效的手术方式。     

椎弓根钉棒内固定同期前路病灶清除植骨治疗腰骶椎结核

目的：探讨采用后路椎弓根内固定加前路病灶清除、植骨融合治疗腰骶椎结核的手术方法及效果。方法：8例腰骶椎结核患者,男5例,女3例,年龄26～39岁。病变部位：L131例,L452例,L5～S11例,L342例,L352例。术前按Frankal分级：D级5例,E级3例。四联抗痨治疗后,采用Ⅰ期后路椎弓根内固定加前路病灶清除、前路减压及植骨融合术,观察术后结核治愈率、植骨融合、畸形矫正和神经恢复情况。结果：平均随访12个月,所有病例切口均Ⅰ期愈合,神经功能恢复为E级,所有植骨块均骨性愈合,局部无复发,内固定无松动、断裂,植骨无移动、吸收。无后突畸形发生。结论：Ⅰ期后路椎弓根内固定加前路病灶清除、前路减压及植骨融合术能有效清除病灶、矫正后突畸形、早期重建脊柱稳定性及促进椎体间植骨的融合,是一种安全有效的治疗方法。     

经皮穿刺引流联合后路病灶清除椎间植骨内固定治疗胸腰段脊柱结核伴巨大脓肿

目的探讨经皮穿刺引流联合后路病灶清除椎间植骨内固定治疗胸腰段脊柱结核伴巨大脓肿的安全性及临床疗效。方法回顾自2007-05—2012-04诊治胸腰段脊柱结核伴巨大脓肿9例。所有患者先行CT引导下穿刺,灌洗引流1~2周后再行后路开放减压、病灶清除、植骨融合内固定术。观察比较手术前后血沉(ESR)、后凸角度、神经功能及植骨融合情况。结果 9例均获得随访18~56个月,平均35个月。手术时间120~260 min,平均165 min;术中失血量300~1 600 ml,平均650 ml。患者术后切口均一期愈合,无窦道形成。术后3个月ESR恢复正常,平均21 mm/h。术后后凸角度3°~16°,平均7°。末次随访时Frankel分级:C级1例,D级4例,E级4例。植骨融合时间3~6个月,平均4个月。结论对于胸腰段脊柱结核伴巨大脓肿者采用经皮穿刺引流联合后路病灶清除椎间植骨内固定是一种安全有效的治疗方法。     

采用可扩张通道下病灶清除植骨融合联合后路内固定治疗腰椎结核

目的探讨采用可扩张通道下病灶清除植骨融合联合后路内固定治疗腰椎结核的临床疗效。方法回顾分析2008年12月-2014年12月采用可扩张通道下病灶清除植骨融合联合后路内固定治疗的17例腰椎结核患者临床资料。男10例,女7例;年龄20~69岁,平均42.6岁。病程1~6个月,平均3.4个月。病变累及节段:L_(1,2)5例,L_(2,3)6例,L_(3,4)3例,L_(4,5)3例。神经功能损害按美国脊髓损伤学会(ASIA)分级,C级2例,D级13例,E级2例。采用疼痛视觉模拟评分(VAS)、日本骨科协会(JOA)评分、Barthel指数评价疗效,并计算JOA评分和Barthel指数改善率;定期随访并复查腰椎X线片、CT,评价腰椎后凸Cobb角纠正情况及植骨融合情况。结果 17例患者手术均成功,术后病理检查均提示腰椎结核感染。所有患者均获随访,随访时间24~48个月,平均35.3个月。随访复查X线片及CT显示死骨清除彻底及椎旁脓肿消失,腰椎后凸Cobb角纠正良好。17例患者术后6个月植骨均达骨性融合;随访期间未发现结核病灶复发,术后18个月结核病变均达到临床治愈。未发现内固定物松动、断裂等并发症。末次随访时,2例术前ASIA分级C级患者中1例恢复至D级,1例恢复至E级;13例术前D级患者中11例恢复至E级,2例无变化;2例术前E级患者术后无神经损害。术后2周及末次随访时VAS评分、JOA评分、Barthel指数及腰椎后凸Cobb角均较术前明显改善,手术前后各时间点间比较差异均有统计学意义(P0.05)。末次随访时,腰椎JOA改善率为75.2%±6.2%,Barthel指数改善率为75.7%±10.8%。结论采用可扩张通道下病灶清除植骨融合联合后路内固定治疗腰椎结核临床疗效良好,是一种安全有效的治疗方法 。     

一期后路保留部分关节突开窗病灶清除短节段椎弓根螺钉内固定治疗腰骶椎结核

目的探讨一期后路保留部分关节突开窗、病灶清除、植骨融合、短节段椎弓根螺钉内固定治疗腰骶椎结核的可行性及疗效。方法 2010年1月-2014年12月对符合选择标准的32例腰骶椎(L4~S1)脊柱结核患者,采用一期后路保留部分关节突开窗、病灶清除、植骨融合、短节段椎弓根螺钉内固定治疗。男20例,女12例;年龄17~62岁,平均43岁。病程12~48个月,平均18个月。病灶累及节段:L5、S1 19例,L4、5 13例。临床效果采用Oswestry功能障碍指数(ODI)及影像学指标(手术前后腰骶角矫正情况及术后X线片骨融合Bridwell分级和CT骨融合标准)评价。结果患者均顺利完成手术,手术时间平均180 min,术中出血量平均400 m L。32例均获随访,随访时间12~67个月,平均15.6个月。末次随访时患者结核中毒症状均消失,无内固定物松动、断裂发生;7例神经症状患者神经功能均恢复正常,美国脊柱损伤协会(ASIA)分级由术前C级2例、D组5例均恢复至E级。术后1年及末次随访时ODI评分均较术前显著改善(P0.05),术后1年及末次随访间比较差异无统计学意义(P0.05)。术后7 d、1年及末次随访时腰骶角均较术前显著增加(P0.05),术后各时间点间比较差异无统计学意义(P0.05)。术后植骨融合时间为9~24个月,平均12个月。术后1年和末次随访时X线片Bridwill骨融合率分别为87.50%(28/32)和93.75%(30/32),CT总融合率分别为87.50%(28/32)和90.63%(29/32),两个时间点间植骨融合情况比较差异有统计学意义(P0.05)。4例出现耐药,经调整抗结核方案1年后3例呈BridwillⅢ级融合,1例呈Ⅳ级融合。结论一期后路保留部分关节突开窗能有效清除病灶,椎体及附件间植骨、短节段椎弓根螺钉内固定能维持术后脊柱可靠的稳定性并获得较满意的植骨融合率,是治疗腰骶椎结核的有效方法。     

前路病灶清除椎体间植骨结合后路椎弓根内固定治疗腰骶椎结核

目的：探讨前路病灶清除椎体间植骨结合后路椎弓根内固定治疗腰骶段结核的临床疗效.方法：对2005年1月至2012年6月收治的18例腰骶椎结核患者进行回顾性分析,男12例,女6例;年龄35～67岁,平均44岁;病程4～17个月,平均9个月.其中单纯腰痛2例,腰痛伴下肢放射痛3例,下肢肌力感觉减退者13例.神经功能Frankel分级：C级3例,D级10例,E级5例.病灶部位：L4.58例,L54例,LS16例.术前腰骶角15°～27°,血沉45～93 mm/h.均采用前路病灶清除椎体间植骨结合后路椎弓根内固定治疗,应用腰骶角测量、血沉检测和神经功能Frankel分级来评估临床疗效.结果：18例均获随访,时间14 ～22个月,手术时间平均180 min;出血量400～800 ml,术中1例发生髂静脉损伤,术后4例出现不同程度腹胀,无脊髓损伤及其他严重并发症,腰腿痛症状均消失,Frankel分级有不同程度提高,X线、CT检查显示18例患者于术后9～13个月植骨融合,腰骶角和血沉末次随访时与术前比较均显著改善（P＜0.05）.结论：前路病灶清除椎体间植骨结合后路椎弓根内固定是治疗腰骶椎结核的一种有效手术方法.     

Ⅰ期后路病灶清除联合腰髂间固定植骨融合术治疗腰骶椎结核

目的：探讨Ⅰ期后路病灶清除联合腰髂间固定植骨融合术治疗腰骶椎结核的临床疗效。方法：回顾性分析2013年1月至2018年2月收治的31例腰骶椎结核患者,均采用Ⅰ期后路病灶清除联合腰髂间固定植骨融合手术治疗。病变范围为L₄-S₂,其中男18例,女13例,年龄18~77（45.9±9.1）岁。采用美国脊柱损伤协会脊髓损伤神经功能分级（ASIA分级）：B级2例,C级17例,D级12例。分析手术前后血红细胞沉降率（ESR）、C-反应蛋白（CRP）、疼痛视觉模拟评分（VAS）、ASIA分级、腰骶角及椎间隙高度变化情况,并观察手术并发症、内植物稳定性和植骨融合情况。结果：31例患者均获随访,时间为10~24（16.0±3.1）个月。1例患者术后出现局部感染、皮下积液,经换药治愈。余30例患者均Ⅰ期愈合,无窦道形成及结核复发。所有患者获治愈,未见内固定松动、断裂;植骨融合均成功,平均融合时间（4.7±1.1）个月。末次随访时患者ESR、CRP均正常,VAS评分为（1.92±0.57）分,低于术前的（6.13±1.21）分;ASIA分级C级2例,D级6例,E级23例。末次随访时腰骶角为（27.21±3.12）°,较术前的（21.42±3.75）°增大;椎间隙高度为（9.80±0.38）mm,高于术前的（7.84±0.41）mm。结论：Ⅰ期后路病灶清除联合腰髂间固定植骨融合术治疗腰骶椎结核是一种切实可行、安全有效的方法,可在临床中推荐应用。     

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.