急性颈脊髓损伤髓内出血水肿患者术后神经功能恢复的风险因素分析

目的 观察伴髓内出血水肿的急性颈脊髓损伤(cervical spinal cord injury, CSCI)患者的手术减压效果,并分析术后神经功能恢复不良的预测因素。方法 回顾性分析该院于2018年3月～2022年3月收治的71例伴髓内出血水肿的急性CSCI患者资料,测量其术前MRI所示的髓内出血信号长度(intramedullary hemorrhage length, IHL)、髓内水肿信号长度(intramedullary edema length, IEL)、脊髓受压指数(maximum spinal cord compression, MSCC)等指标。于术前、术后3 d时,评价其ASIA运动评分(the ASIA motor score, AMS),并计算其AMS恢复率;术后6个月,以AIS分级改善≥1级判定为术后神经功能恢复(改善组),以AIS分级未改善甚至加重判定为术后神经功能未恢复(未改善组)。比较两组患者的相关资料,并采用多元Logistic回归分析得出CSCI患者术后神经功能恢复不良的预测因素。结果 术后6个月,有54例(76.1%)患者的神经功能AIS分级改善...     

无放射学异常颈脊髓损伤16例临床分析

目的分析颈椎管狭窄(cervical canal stenosis,CSS)无放射学影像异常的脊髓损伤(spinal cord injuries without radiographic evidence of trauma,SCIWORET)患者的特点,评估四肢功能恢复情况。方法回顾性分析2009年5月至2013年6月我科收治的颈脊髓损伤患者175例,发现其中16例为颈椎管狭窄无放射学异常脊髓损伤患者,男9例,女7例;年龄35~86岁,平均65.7岁。所有病例Torg比值小于0.8,脊髓椎管比值(medullary canal ratio,MCR)大于0.65,无颈椎骨折脱位,关节突交锁。美国脊髓损伤协会(American Spinal Injury Association,ASIA)脊髓功能分级:A级3例,B级4例,C级4例,D级5例。11例手术治疗,5例采取保守治疗。由同一医生评估患者四肢损伤后1周、1个月、6个月和1年ASIA运动评分(ASIA motor score,AMS)和ASIA感觉评分(ASIA sensory score,ASS),并进行统计学分析。结果 ASIA分级A级2例死亡,B级、C级以及1/2D级患者均恢复1级。1例79岁患者(病例8)和1例74岁患者(病例12)在损伤后1个月内死亡,1例患者(病例7)术后失访。2例死亡患者均为完全四肢瘫,神经损伤平面C4、C5。损伤后1年AMS上升(11.3±3.1)分,运动评分恢复率39.4%,AMS恢复最显著在伤后1周到1个月(6.6分或28.2%),伤后1~6个月恢复0.8分或4.8%,60岁以下患者恢复程度(12.6±4.4)分大于60岁以上患者(8.1±3.6)分(P0.05)。损伤后1年ASS上升(14.3±4.0)分,感觉评分恢复率38.6%,ASS恢复最显著在伤后1周(8.7分或32.0%),伤后1~6个月恢复0.2分或1.2%,60岁以下患者恢复程度(14.7±5.2)分大于60岁以上患者(8.1±5.3)分(P0.05)。结论不全四肢瘫患者神经与四肢功能恢复主要在受伤后前6个月,完全四肢瘫患者受伤后早期死亡率高。     

腰脊髓损伤伴严重多发伤的外科治疗

目的:探讨腰脊髓损伤为主严重多发伤的救治方法。方法:回顾性分析42例以腰脊髓损伤为主严重多发伤患者的临床资料,创伤严重度(ISS评分)为20～57分,平均(34.60±3.57)分。平均受伤部位约3处。脊髓损伤节段L1-L5,其中单节段损伤29例,2节段以上损伤13例。脊髓损伤(按ASIA分级):A级8例,B级7例,C级12例,D级15例。均采用椎管减压、植骨内固定术重建脊柱稳定性。结果:所有患者获得随访,时间6个月～4年,平均1年4个月,腰背痛症状均明显缓解,生活可自理,无内固定断裂及松动,植骨均融合。随访时脊髓损伤(按ASIA分级):A级5例,B级4例,C级6例,E级27例。27例神经症状完全恢复,8例有1级以上恢复,7例无变化。结论:腰脊髓损伤为主严重多发伤急诊应遵循伤害控制原则,尽早采取手术治疗重建脊柱稳定性,恢复神经功能,减少残疾。     

经椎间孔腰椎椎体间融合术在胸腰段爆裂性骨折手术中的应用

目的 探讨经椎间孔腰椎椎体间融合术(TLIF)在胸腰段爆裂性骨折手术中的作用.方法 2010年1月至2012年1月应用TLIF技术治疗椎体前缘高度丢失大于50％,椎管占位率大于40％的胸腰段单节段爆裂性骨折患者共23例,男15例,女8例;年龄22～61岁,平均45.3岁;损伤节段:T12 5例,L115例,L23例.骨折按照Denis分型:均为爆裂性骨折.脊髓神经功能受损情况按美国脊髓损伤协会(ASIA)脊髓神经功能障碍分级:A级1例,B级2例,C级7例,D级11例,E级2例.结果 本组患者手术时间100～160 min,平均140 min;出血量200～750 mL,平均370 mL.无术中、术后并发症发生.术后随访5 ～ 24个月(平均12.3个月),末次随访时脊髓神经功能按ASIA分级:A级1例,B级1例,C级4例,D级7例,E级10例,平均提高1.8级.伤椎前缘高度由术前45.2％±17.6％恢复至术后90.2％±13.7％,后缘高度由术前81.5％±14.3％恢复至术后93.5％±15.4％,cobb角由术前28.4°±11.8°改善至术后6.4°±3.8°,以上指标差异均有统计学意义(P＜0.05).结论 TLIF技术可用于胸腰段爆裂性骨折的治疗,能完成对骨折的减压、固定和前柱的支撑植骨融合,值得推广应用.     

道路交通伤致急性脊髓损伤的临床研究

目的 探讨道路交通伤致急性脊髓损伤的治疗,以期提高救治效果.方法 2005年6月至2008年10月收治64例因交通伤致急性脊髓损伤患者,男57例,女7例;年龄4～65岁,平均43.7岁;受伤至入院时间2.5 h～7 d,平均39.7 h.根据8 h内入院和8 h后入院分为A、B两组.根据美国脊髓损伤协会(ASIA)分级:A级14例,B级23例,C级17例,D级10例.所有患行均接受激素治疗,58例患者采用手术治疗,6例采用非手术治疗.比较A、B两组患行的ASIA分级改善率.结果 64例患者无一例死亡,获6～24个月(平均17.3个月)随访.A组26例患者中,治疗后有22例肢体功能得到不同程度的恢复,根据ASIA分级,平均改善等级为1.5±0.9.B组38例患者中,治疗后有12例肢体功能得到不同程度的恢复,根据ASIA分级:平均改善等级为0.9±0.6,A组改善率高于B组,差异有统计学意义(P＜0.05).总体ASIA改善等级为1.1.结论 交通伤导致的脊髓损伤程度重,治疗效果不理想,转送救治时间长是影响治疗效果的重要原因,有必要改进急救器械和转送方式.     

急性颈椎间盘损伤合并脊髓损伤的机制和预后

[目的]探讨急性颈椎间盘损伤合并脊髓损伤的临床特点、损伤机制、手术方法和预后.[方法]临床资料回顾性分析,2000～2008年收治急性颈椎间盘损伤合并脊髓损伤患者25例,伤后X线平片均显示无骨折脱位,MRI均有不同程度的颈椎间盘损伤和脊髓损伤异常信号.颈椎屈曲型损伤16例.按美国脊髓损伤学会脊髓神经功能分级(ASIA标准):A级1例,B级9例,C级12例,D级3例.23例行颈前路间盘切除减压与固定手术,2例合并椎管狭窄者行前后路联合手术.早期介入康复治疗.术前、后ASIA运动评分和日常生活动作能力评分,评价神经功能,动力位X线片评价颈椎稳定性,MRI评价脊髓状况.[结果]颈椎屈曲型损伤占64%,术前颈椎生理前凸减小占84%.随访平均38个月.植骨全部融合,动力位X线片测量均显示颈椎稳定性良好.伤后1周内MRI表现单纯脊髓水肿者85%获得提高1～2个级别的恢复;髓内出血信号长度<4 mm者60%获得提高1个级别的恢复;髓内出血信号长度>4 mm者2例均无恢复.平均ASIA运动评分由45.52±16.05增至85.74±9.36,日常生活动作能力评分由36.32±11.47增至82.54±9.81,差异有统计学意义(P<0.05).[结论] 急性颈椎间盘损伤是无骨折脱位刑脊髓损伤的原因之一,颈椎损伤多为屈曲型,颈椎生理曲度减小是损伤前置因素,脊髓损伤多为不完全性,预后相对较好.颈前路减压与固定手术可为脊髓损伤修复创造有利条件.     

骨质疏松性腰椎骨折合并脊髓损伤的手术治疗

目的探讨椎体成形辅助椎弓根螺钉固定治疗骨质疏松性腰椎骨折合并脊髓损伤的临床疗效。方法2006年7月-2007年9月,对7例患者应用此法治疗。平均随访11.6个月（6-20个月）。按ASIA分级标准检查神经功能,用X线片测量伤椎术前、术后后凸畸形的角度和椎体前缘高度进行临床评价。结果7例患者中神经功能由C级恢复到D级4例、恢复到E级1例,由D级恢复到E级2例。伤椎椎体前缘高度压缩率术前为53.00%±9.59%,术后为72.00%±6.70%,丢失4.00%±3.72%（P〈0.01）;后凸畸形角度术前为21.00°±6.57°,术后为8.00°±4.18°（P〈0.01）,丢失2.00°±2.67°（P〈0.05）。7例患者均无骨水泥渗漏,1例出现椎弓根螺钉松动。结论椎体成形辅助椎弓根螺钉固定术是对骨质疏松引起的腰椎骨折合并脊髓损伤的一种有效治疗方法。     

采用ASIA 2000标准对脊髓损伤患者步行能力的预后评估

目的：探讨ASIA 2000标准部分项目对脊髓损伤患者步行能力预后评估的作用。方法：对2003年9月至2004年9月中国康复研究中心收治的42例脊髓损伤患者采用ASIA 2000标准部分项目进行连续性临床观察。比较患者伤后1个月时的神经功能与伤后1年步行能力，判定该标准部分项目对脊髓损伤步行能力预后评估的作用。结果：残损分级相同的情况下，截瘫患者步行能力恢复好于四肢瘫患者；神经平面基本一致的情况下，伤后1个月时残损分级越高的患者，伤后1年时的步行能力越好；神经平面基本一致的情况下，伤后1个月时下肢运动评分越高的患者，伤后1年时的步行能力越好。结论：神经平面是影响步行能力预后的因素之一，残损分级相同的截瘫患者步行能力恢复好于四肢瘫患者。不论是截瘫患者还是四肢瘫患者，残损分级与步行能力预后有相关关系。下肢运动评分与神经平面相结合可以对脊髓损伤患者步行能力进行预后估计。     

胸椎骨折脱位合并脊髓损伤的手术治疗

目的 探讨胸椎骨折脱位合并脊髓损伤的手术方法及疗效.方法 2005年4月至2008年3月,采用后路减压植骨融合长节段椎弓根钉内固定和短节段椎弓根钉联合伤椎固定的方法治疗胸椎骨折脱位合并脊髓损伤患者12例,其中T2 1例,T3 1例,T4 2例,T5 3例,T7 1例,T102例,T112例.术前神经损伤按照ASIA分级:B级4例,C级5例,D级3例.观察术前、术后随访的X线及CT片,比较伤椎的Cobb角、椎体高度丢失率和神经损伤的变化情况.结果 12例患者获12～48个月(平均28个月)随访,切口均一期愈合,骨折愈合时间6～15个月,平均10个月.术后并发症:肺部感染1例,深静脉血栓1例,均经处理后痊愈,无内固定失效发生.术前Cobb角平均20.7°±2.5°,末次随访时平均6.8°±0.3°,差异有统计学意义(t=7.573,P=0.023).术前椎体高度丢失率平均40.6%±5.1%,末次随访时平均8.5%±1.1%,差异有统计学意义(t=26.509,P=0.009).术后神经损伤按照ASIA分级:B级2例改善为C级,2例改善为D级;C级3例改善为D级,2例改善为E级;D级3例均改善为E级,无加重患者.结论 胸椎骨折脱位合并脊髓损伤的手术方式以后路椎弓根固定为主,中上胸椎骨折应采用长节段固定,下胸椎骨折可以采用短节段联合伤椎固定,术前充分准备以及术中仔细操作可获得满意疗效.     

后路部分椎体切除治疗合并神经损伤的难复性下腰椎爆裂性骨折

目的探讨后路部分椎体切除治疗合并神经损伤的难复性下腰椎爆裂性骨折的疗效。方法回顾性分析2014年3月—2018年10月收治的28例合并神经损伤的难复性下腰椎爆裂性骨折患者临床资料,载荷分享评分(LSC)6 ～ 9(7.2±1.1)分;高处坠落伤7例,交通伤15例,重物砸伤6例;L_3骨折18例、L_4骨折7例、L_5骨折3例,其中6例合并邻近椎体压缩性骨折;马尾神经损伤10例,神经根损伤4例,两者均有损伤14例;受伤至手术时间2 ～ 7(3.4±1.4)d。记录手术时间、术中出血量,对疼痛视觉模拟量表(VAS)评分、伤椎椎体前缘高度比、Cobb角及神经功能美国脊髓损伤协会(ASIA)分级改善情况进行评价。结果所有手术均顺利完成,手术时间(163.9±22.4)min,术中出血量(652.1±95.5)mL。所有患者随访12 ～ 30个月,平均16.7个月。术后VAS评分、伤椎椎体前缘高度比和Cobb角均较术前显著改善,差异有统计学意义(P 0.05)。神经功能ASIA分级,术前A级1例术后仍为A级;术前B级4例,术后恢复至C级3例、D级1例;术前C级15例,术后恢复至D级11例、E级4例;术前D级8例,术后仍为D级4例,恢复至E级4例。结论后路部分椎体切除治疗合并神经损伤的难复性下腰椎爆裂性骨折疗效满意。     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

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.