人工血管内支架与腹主动脉的生物相容性

目的评价人工血管内支架与腹主动脉的生物相容性。方法用膨体聚四氟乙烯膜压于镍钛合金支架制成人工血管内支架,将其植入实验猪肾下腹主动脉。2、4、12周取材,切片行苏木素伊红(HE)染色、胶原纤维和弹力纤维染色、血管平滑肌细胞α肌动蛋白免疫组织化学检查以及细胞原位凋亡检测,并行图像分析,对照实验组与正常腹主动脉内膜厚度、胶原纤维和弹力纤维相对含量、血管平滑肌细胞密度和凋亡比例。结果实验组2周时人工血管内支架表面有内皮细胞覆盖,与正常组相比,其各时间点内膜增生显著(P<0.01),弹力纤维和胶原纤维的形态和分布基本正常(P>0.05),2、4周时中膜内血管平滑肌细胞密度和凋亡比例显著高于正常组(P<0.01)。结论人工血管内支架与腹主动脉有着良好的生物相容性,但内膜增生较明显。     

不同长度自体静脉移植对修复动脉缺损早期影响的实验研究

本研究通过动物实验，观察不同长度自体静脉移植对修复动脉缺损早期的影响。将兔自体耳静脉分别取８、１２、１６、２０ｍｍ移植到自体股动脉，修复动脉缺损。８周时，行肉眼观察，电磁血流量测量，光镜和电镜下观察移植静脉的组织学及超微结构的变化，综合判断自体静脉移植的长度因素对血管近期通畅率和血管功能的影响，结果表明：（１）静脉移植长度因素对早期血管通畅率不构成影响（Ｐ值＞０．０５）。（２）自体静脉移植后血管口径增大，静息状态下血流量增加（Ｐ值＜０．０５）。（３）形态学观察，静脉移植后该段静脉有明显的动脉化趋势，内皮细胞修复管腔面，中膜平滑肌层数增多，弹力纤维增生，仍保持血管壁的三层结构。（４）随着血管移植长度的增加，内膜增生明显，中膜胶原纤维组织增多，内皮细胞修复不完全，弹力纤维增生减少，提示：移植长度过长，可能构成对血管功能的影响。     

液压扩张对动脉作用的组织学变化

目的 探讨液压扩张对动脉各层结构的影响。方法 用生理盐水在不同压力（４０、８０、１２０ ｋＰａ）下对新西兰大白兔颈总动脉行液压扩张，观察内皮细胞、内弹力膜、一滑肌及外膜的变化，测量动脉管径、平滑肌与内膜的厚度。结果（１）动脉液压扩张后管径增大；（２）压力为４０ｋＰａ时，内皮细胞、内弹力膜与平滑肌的损伤轻，１周后均恢复正常；（３）压力超过８０ｋＰａ时，动脉各层的损伤逐渐加重，修复需要的时间长而且修复     

可降解外套管减轻自体移植静脉内膜增生的动物模型建立

目的建立可降解外套管束缚自体移植静脉减轻静脉内膜增生的动物模型,探讨可降解材料做外套管对防止或延缓桥静脉再狭窄的可行性.方法以"no-touh"方法取犬股静脉,调转后移植到同侧股动脉,其中一侧加用聚乳酸-聚乙醇酸(PLGA)做成的圆柱形外套管(外套管组),另一侧单纯静脉移植(对照组).超声多普勒观察移植静脉是否通畅.术后4周和24周再次手术取移植静脉段.病理切片行苏木素-伊红hE)染色测量移植静脉中段内膜、中层厚度;维多利亚蓝(VB)染色观察胶原纤维、弹力纤维;免疫组织化学平滑肌α-actin抗体染色鉴定静脉平滑肌.结果(1)所有动静脉吻合口无狭窄,术后早期,外套管组2条静脉血栓形成、闭塞,对照组1条静脉血栓形成、闭塞;(2)外套管变化术后4周内外套管无变形,6周开始变形,24周完全降解;(3)静脉内膜和中层厚度外套管组静脉内膜增生轻,厚度均匀,对照组静脉内膜不均匀增厚,术后4周和24周外套管组静脉中段的内膜及中层厚度均显著小于对照组,差异有非常显著性 (P< 0.01); (4)移植静脉新生内膜主要由平滑肌细胞(SMCs)和胶原纤维构成,术后4周和24周对照组两者含量丰富,而外套管组含量少于对照组且排列整齐.结论该动物模型设计合理,PLGA可以做移植静脉的外套管材料,外套管降解前后均可明显减轻移植静脉内膜和中层增生,减少平滑肌细胞和胶原纤维在内膜沉积.     

人arresten基因转染对自体移植静脉内膜增生的影响

目的:探讨体内转染arresten基因对自体移植静脉内膜增生的影响。方法:建立大鼠自体静脉移植模型。血管吻合术前，用脂质体介导重组质粒pSecTag2-AT（Ⅰ组），空载体pSecTag2转染（Ⅱ组）移植血管，等体积脂质体溶液处理移植血管(空白对照组，Ⅲ组）。各组动物均于4周后切取移植血管，RT-PCR检测移植血管中arresten mRNA的表达；常规HE，Verhoeff弹力纤维染色；计算机图象分析检测移植静脉血管内膜及中膜面积、厚度；免疫组化检测移植血管内膜α-SMA及PCNA的表达；Western blot检测TGF-β1蛋白的表达。结果:Ⅰ组转染的移植静脉中有目的基因mRNA的表达, 而Ⅱ、Ⅲ组无Ⅰ组内膜、中膜面积小均于Ⅱ组和Ⅲ组，差异有显著性（P<0.05）。而内膜面积/中膜面积3组间无统计学差异（P>0.05）；Ⅰ组内膜厚度小于Ⅱ组和Ⅲ组，组间比较有统计学差异（P<0.01）；α-SMA染色表明增生内膜中的细胞是血管平滑肌细胞；PCNA阳性细胞数及表达指数Ⅰ组均低于Ⅱ组和Ⅲ组（P<0.05）；Ⅰ组TGF-β1蛋白的表达明显低于Ⅱ组和Ⅲ组。结论:移植血管转染arresten基因，可有效抑制自体移植静脉内膜的增生，在防治血管移植术后再狭窄方面显示出良好的临床应用前景。     

移植动脉慢性排斥反应的病理组织学观察

目的 了解慢性排斥反应时移植动脉硬化的病理变化。方法 采用病理图象定量分析及电镜等检测手段,观察大鼠动脉移植后3、7、14、20、30及60d的病理变化。结果 同系移植对照组除供者血管冷缺血超过1h的2只术后14d内膜轻度增生外,基余移植动脉与受者自身的正常动脉比较,差异不显著;异系移植实验组术后3d血管外膜有大量炎性细胞浸润,7d时局部内皮剥脱,14d内膜中层细胞通过弹力膜裂隙向内膜迁移,内膜增生,20d内膜全层或局部呈8半月形增生,平滑肌细胞形态由收缩型转变为合成型,30d内膜细胞数达峰值,60d内膜持续增厚,基质纤维成分增多,内膜修复。结论 移植体动脉硬化具有内皮剥脱、炎性细胞浸润、中层坏死、平滑肌细胞迁移及内膜增生4大特点。     

反应器内构建组织工程血管平滑肌层的实验研究

目的 探讨生物反应器内构建组织工程血管的可行性.方法 于6个月龄犬颈总动脉血管获取平滑肌细胞,经体外培养扩增后接种于聚羟基乙酸(PGA)上,形成细胞-材料复合物,并将其置于生物反应器内培养.实验组模拟成年哺乳动物循环系统的参数予以动态力学刺激培养(搏动频率:75次/分;扩张量＜5%);对照组为静态培养,其余与实验组相同,分别于3与6周后取材检测.结果 生物反应器内培养的血管大体观察具有良好的弹性,管腔圆,色泽光亮;HE染色显示平滑肌纤维成分排列较规则,有层次感;弹力纤维染色显示弹力纤维成分较多而密;免疫组织化学检测显示为棕黄色层状排列的平滑肌纤维.对照组弹性欠佳,管腔塌陷,色泽暗淡;平滑肌纤维与弹力纤维成分较少且排列紊乱,层次感差.结论 应用生物反应器可构建具有良好结构的血管样结构的平滑肌层组织.     

实验性自体静脉移植平滑肌细胞增殖周期动力学研究

为观察移植静脉平滑肌细胞增植周期变化，取１２０只大鼠建立自体颈静脉移植于腹主动脉动物模型，分别于移植早期（２ｈ，６ｈ，２４ｈ），移植中期（１ｗ，２ｗ，４ｗ），以透射电镜观察其超微结构，流式细胞仪检测整体移植血管增殖活性，利用ＰＣＮＡ免疫组化观察平滑肌细胞增殖活性及增殖平滑肌细胞在血管中分布。结果表明：（１）自体静脉移植早期虽然组织学未见平滑肌细胞数量明显增加，但平滑肌细胞增殖业已启动；移植中期，平滑肌细胞大量增殖移行；（２）在增殖细胞的分布上，移植早期，局限于血管中膜；移植中期，内膜及中膜均表现出较高增殖率。因此，移植静脉平滑肌增殖、移行的控制应着力于移植术后２周内。     

非限制性外支架防治移植静脉狭窄的早期形态学观察

目的 探讨非限制性外支架防治移植静脉内膜增生的效果及其可能的作用机制。方法新西兰白兔36只随机分成两组，每只均实施颈外静脉-颈总动脉移植术，支架组（S组）在移植静脉外套以直径6mm的非限制性涤纶外支架，对照组（NS组）移植静脉外无外支架，分别于术后7、14、28d取材进行观察。术后应用彩色多普勒超声观察移植静脉的通畅情况。组织切片进行HE和弹力VG染色和抗α-平滑肌肌动蛋白（α-SMA）免疫组织化学染色。采用计算机图像分析系统测量移植静脉内膜、中膜的厚度和面积，管腔面积，并计算内膜增值率（即内膜面积，内弹力板包围面积）。结果（1）S组术后死亡1只，闭塞性血栓形成1只，在支架与移植静脉之间有“果冻样”物质（新外膜）形成；NS组术后偏瘫并死亡1只，血栓形成1只。超声检查移植静脉通畅情况与取材时结果完全一致。（2）染色显示：术后7-28d，S组和NS组移植静脉内膜和中膜逐渐增生，S组新外膜为肉芽肿样增生，内有较多炎症细胞浸润。（3）计算机图像分析结果：S组和NS组内膜、中膜的厚度和面积均逐渐增加，术后7d时，S组的内膜厚度、面积和内膜增生率与NS组的差别无统计学意义，P〉0．05；术后14、28d，S组的内膜厚度、面积和内膜增生率均小于NS组，P〈0．05；术后1-4周，S组的中膜的厚度、面积均小于NS组，P〈0．05。结论非限制性外支架可以抑制移植静脉内膜和中膜增生；在非限制性外支架和移植静脉之间可以生成新外膜，新外膜的生成在防治内膜增生的过程中可能发挥了重要作用。     

脐血管去内皮细胞后血管顺应性及抗原表达量变化的实验研究

目的 评价酶原法、低温法去除脐血管内皮细胞的优劣，为研究开发符合生理、无排斥、结构和功能类似自体的血管支架提供理论依据。方法 自愿捐赠的健康、足月顺产、无损伤胎儿新鲜脐动、静脉各60根，每根长10cm，抗生素液37C灭菌24h后，分为正常组、酶原组和冷冻组（n=20）。分组时每根血管取0．5cm细菌培养。酶原组加入0．1％Ⅱ型胶原酶后夹闭两端，37C水浴消化5、10、15、20min，去除内皮细胞；冷冻组置入冷存管中，加入DMEM培养液，逐步冷冻，最后置入液氮中，贮藏24h以上，37C水浴30～60s快速复温，无菌生理盐水灌冲血管腔数次，去除残留血管内皮细胞；正常组4CKerb’s保存液恒温存放。将标本分别行HE、弹力纤维及胶原纤维染色及扫描电镜观察；比较各组血管顺应性差异；采用免疫组织化学染色测定人类白细胞抗原ABC（human leukocyte antigen ABC，HLA-ABC）和HLA-DR，分析抗原表达量的变化。结果 各组标本均无细菌生长。组织学观察：冷冻组，内皮细胞完全去除，脐动脉显示内皮下发达的纵行平滑肌层，脐静脉可见内弹力膜；酶原组，胶原酶作用20min，血管内皮细胞完全去除，脐动脉露出内层纵行平滑肌细胞，脐静脉显示内皮下层。血管顺应性：冷冻组脐血管顺应性大于正常组，正常组大于酶原组，但组间差异均无统计学意义（P〉0．05）；脐静脉的顺应性约为脐动脉的2～3倍。HLA-ABC、HLA-DR免疫组织化学染色：冷冻组、酶原组与正常组比较，脐动、静脉抗原性均明显降低（P〈0．01）；冷冻组与酶原组比较，脐动、静脉HLA-ABC、HLA-DR抗原表达量均降低，且差异有统计学意义（P〈0．01）。结论冷冻法及0．1％Ⅱ型胶原酶作用20min均可完整去除脐血管内皮细胞，低温冷冻法优于酶原法。     

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 comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.     

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.