骨盆原发恶性骨肿瘤的手术治疗

目的探讨骨盆恶性肿瘤不同的切除、重建方式及并发症。方法1997年7月至2003年7月，收治骨盆原发恶性骨肿瘤患者76例，男47例，女29例。软骨肉瘤31例、尤文肉瘤15例、骨肉瘤7例、淋巴瘤3例、恶性纤维组织细胞瘤3例、血管外皮瘤1例、骨髓瘤3例、骨巨细胞瘤13例。根椐Enneking骨盆肿瘤分区，行Ⅰ区髂骨翼局部切除重建16例；Ⅲ区耻、坐骨局部切除9例；Ⅱ区髋臼周围肿瘤切除与髋臼重建30例(人工半骨盆8例、马鞍式关节7例、肿瘤骨灭活再植 人工髋关节置换6例及肿瘤刮除 骨水泥填充 人工髋关节置换术9例)及半骨盆截肢2l例。随访时间为16个月-6年。结果(1)21例行半骨盆截肢术的患者中4例局部复发(19％)，原因为肿瘤累及骶髂关节的骶骨侧。25例行Ⅰ区或Ⅲ区肿瘤切除的患者中7例局部复发(28％)，主要原因是切缘离髋臼太近。21例行Ⅱ区肿瘤切除髋臼重建的患者中4例局部复发(19％)，与肿瘤巨大、切除边缘可能残留肿瘤有关。(2)行Ⅰ区或Ⅲ区肿瘤切除的患者，术后行走功能基本正常。行Ⅱ区肿瘤切除髋臼重建的患者，术后2个月能正常坐与持拐行走，半年后部分患者步态接近正常。(3)3例死于围手术期并发症，其余患者术后症状缓解率为90％。12例出现伤口并发症，8例需手术治疗。结论骨盆肿瘤切除重建的原则是首先完整切除肿瘤，其次考虑功能重建。髋臼重建方法的选择应权衡各种方法的优缺点，尽量减少并发症的发生。     

累及骶骨的骨盆恶性肿瘤切除及重建

目的 探讨累及骶骨的骨盆恶性肿瘤合理的手术切除及重建方式.方法 1999年7月至2007年7月,共有19例累及骶骨的骨盆恶性肿瘤患者在北京大学人民医院骨肿瘤科接受肿瘤切除重建手术.平均年龄37岁(12～78岁);男性12例,女性7例. 其中,软骨肉瘤5例、尤文肉瘤4例、骨肉瘤4例、恶性纤维组织细胞瘤(MFH)1例、骨巨细胞瘤1例、转移癌4例.切除髂骨翼及部分骶骨、保留髋臼手术10例,采用了钉棒系统内固定,其中5例患者同时进行了自体腓骨或髂骨植骨;切除部分骶骨、髂骨翼及髋臼手术9例,应用组配式人工半骨盆重建骨盆环完整性.结果 肿瘤学结果:7例出现局部复发(7/19,36.9%),其中骨肉瘤2例、软骨肉瘤2例、尤文肉瘤2例及转移癌1例.19例患者随访时间为1至7年,平均4.5年.功能结果:9例保留髋臼、钉棒重建的患者术后正常行走,无步态异常.9例行Ⅱ区肿瘤切除、人工半骨盆重建的患者中,8例术后2个月能够扶拐行走.ISOLS评分平均20分以上,其中,良好3例,一般5例,较差1例.人工半骨盆重建的患者中,术后脱位1例,行切开复位;因深部感染取出假体1例.结论 对于保留髋臼的髂骨肿瘤切除,采用钉棒内固定结合自体骨植骨是一种理想的重建骨盆环稳定性的方法,可使患者早期恢复行走功能.将股骨头颈植于骶骨侧方,将组配式人工半骨盆卡于质骨块的下方,重建累及骶骨及髋臼的骨盆切除,是一种可取的重建方式.     

骨盆肿瘤的手术治疗

[目的]探讨骨盆肿瘤切除、重建方式及并发症。[方法]根据Enneking骨盆肿瘤分区，行Ⅰ区髂骨翼部分切除4例，部分切除＋重建3例；Ⅱ区髋臼周围肿瘤切除后异体半骨盆重建1例；Ⅲ区耻骨局部切除3例；Ⅰ、Ⅱ区转移瘤肿瘤血管介入与化疗1例；Ⅰ、Ⅲ区肿瘤切除＋重建1例。[结果]7例良性肿瘤中1例Ⅰ区巨细胞瘤刮除术后局部复发，二次手术切除治愈，术后全部功能正常。5例原发恶性肿瘤中2例Ⅰ区淋巴瘤术后化疗，局部无复发，功能良好；2例Ⅰ、Ⅲ区和Ⅰ区肿瘤切除后重建，半年后可持拐下地，1a后步态接近正常；1例Ⅱ区肿瘤切除，异体半骨盆置换患者，术后出现伤口感染不愈及局部肿瘤复发。1例Ⅰ、Ⅱ区转移瘤血管介入＋化疗后存活2a。[结论]骨盆肿瘤的手术切除首先应考虑完整切除肿瘤，然后再考虑重建，术者要权衡各种方法的优缺点，尽量减少并发症的发生。     

髋臼及其周围肿瘤的分区与重建方法

目的 回顾性分析髋臼及其周围恶性肿瘤行整块切除、不同方法髋臼重建的疗效.方法 72例髋臼及其周围恶性肿瘤患者接受了肿瘤整块切除、髋臼重建手术,男42例,女30例;年龄16～78岁,平均41岁.软骨肉瘤39例、骨肉瘤10例、骨巨细胞瘤9例、Ewing肉瘤5例、恶性纤维组织细胞瘤3例、恶性神经鞘瘤2例、血管外皮瘤l例、单发转移癌3例.肿瘤累及Ⅱ区、Ⅰ+Ⅱ区、Ⅱ+Ⅲ区、Ⅰ～Ⅲ区、Ⅰ～Ⅳ区和Ⅱ+Ⅲ+Ⅴ区者分别为4、16、29、7、10和6例.髋臼重建包括组配式人工半骨盆50例、马鞍式关节置换7例、骨盆灭活再植8例、股骨近端与盆骨融合7例.结果 61例获得随访,平均随访3.5年(1～8年).11例局部复发,8例深部感染,6例脱位.45例行组配式人工半骨盆置换术患者ISOLS评分平均22分.优7例、良24例、可9例、差5例.其中优良病例均为累及Ⅱ区和Ⅱ+Ⅲ区者,评分差的病例均为累及Ⅳ区者.5例行马鞍式关节置换、5例骨盆灭活再植和6例股骨近端与盆骨融合术患者,ISOLS评分平均为10、17和14分.结论 髋臼周围肿瘤切除后重建方法以组配式人工半骨盆置换术后功能最好,骨盆灭活再植次之,马鞍式关节置换术后功能最差.组配式人工半骨盆置换对单纯Ⅱ区肿瘤切除重建功能最好,其次为Ⅱ+Ⅲ区、Ⅰ+Ⅱ区、Ⅰ～Ⅲ区、Ⅱ+Ⅲ+Ⅴ区,术后功能最差为Ⅰ～Ⅳ区.     

髋臼周围肿瘤切除后的功能重建

 骨盆肿瘤切除术后骨盆环的重建十分必要，这种重建对于患者术后的坐、立和行走功能非常重要。髋臼部位肿瘤多数为髂骨或耻、坐骨同时受累。 常见肿瘤包括软骨肉瘤、骨巨细胞瘤、Ewing肉瘤、成骨肉瘤等。半骨盆截肢可以达到根治性切除的目的，但因为丧失了患侧肢体，患者多难以接受。近20年来，随着诊断技术、新辅助化疗的发展及肿瘤外科切除原则的建立，骨盆肿瘤的切除及功能重建有了很大的进步。目前，可选择的髋臼重建方法有：瘤骨灭活再植、异体半骨盆移植及人工半骨盆假体重建等。     

髋臼周围肿瘤的切除与重建

目的 探讨髋臼周围肿瘤切除与重建的方式及合并症。方法 回顾分析1997年7月至2003年7月髋臼部位原发肿瘤患者行肿瘤切除重建手术的临床资料。3l例患者中,男性19例,女性12例,年龄12～78岁,平均年龄37岁。其中,软骨肉瘤12例、尤文瘤1例、骨肉瘤3例、淋巴瘤1例、癌肉瘤1例、恶性纤维组织细胞瘤1例、骨髓瘤2例、骨巨细胞瘤9例、动脉瘤样骨囊肿1例。2l例患者行髋臼切除、骨盆重建,其中人工半骨盆8例、马鞍式关节7例、灭活再植 人工髋关节置换6例。10例患者行肿瘤刮除 骨水泥填充 人工髋关节置换。结果 21例行Ⅱ区肿瘤切除、髋臼重建的患者中,5例出现局部复发,其中3例为行半骨盆灭活再植的患者。3例骨肉瘤中2例死亡;12例软骨肉瘤患者中,随访9人,6例无瘤生存。术后2个月后,21例患者能够正常坐、扶单拐行走。结论 髋臼区域的肿瘤切除后可行异体或人工半骨盆移植进行修复,或将瘤段骨壳灭活再植进行重建。髋臼周围肿瘤切除重建的过程中应注意：(1)广泛切除肿瘤;(2)熟悉各种髋臼重建方法的优缺点,防止合并症的发生;(3)髋臼重建后的稳定性较差,应注意站立时在健侧拄一手杖,保护再造髋关节;(4)预防皮缘坏死及伤口感染,骨盆肿瘤切除容易发生伤口问题。     

计算机辅助骨盆肿瘤精确切除和功能重建

目的探讨计算机辅助设计(computer-aided design,CAD)在确定骨盆肿瘤切除边界、重建骨盆和髋关节结构中的应用价值。方法 2006年11月-2009年4月收治5例骨盆肿瘤患者。男3例,女2例;年龄24～62岁,平均36.4岁。骨肉瘤、骨巨细胞瘤、血管肉瘤各1例,软骨肉瘤2例。根据Enneking骨盆肿瘤分区:Ⅰ区、Ⅰ+Ⅱ区、Ⅲ区、Ⅳ区、Ⅰ+Ⅳ区各1例。按反求工程的基本原理,采用CT、MRI扫描获取患者骨盆二维数据,计算机三维重建建立骨盆解剖模型,将解剖模型输入CAD软件精确界定肿瘤切除范围,并设计个性化辅助手术模板、个性化假体以及模拟肿瘤切除、骨缺损修复重建过程。术中按照CAD方案精确切除骨盆肿瘤组织,采用外形匹配的同种异体髂骨加内固定或同种异体髂骨加个性化假体修复肿瘤切除后骨缺损,重建骨盆。结果 5例患者均顺利完成手术,手术时间平均7.9 h,术中出血量平均3 125 mL。术后1例出现切口内积血,1例出现脑脊液漏,均对症处理后痊愈。5例均获随访,随访时间24～50个月,平均34.5个月。患者均于术后4～6周扶双拐部分负重行走,3～6个月恢复行走功能。2例于术后18个月局部复发,1例行局部肿瘤再切除术、1例行局部放疗,无再复发。术后24个月采用国际保肢学会(ISOLS)推荐的骨肿瘤保肢术疗效评价标准进行功能评定,获优2例,良3例。结论采用CAD设计的个性化辅助手术模板、个性化假体及模拟手术过程,保证了骨盆肿瘤切除的精确性和可靠性,将骨盆肿瘤的切除和功能重建提升到个体化治疗阶段,可获得较好的疗效。     

髂骨翼肿瘤的切除与重建

目的 探讨髂骨翼肿瘤切除及重建方式。方法1998年7月至2004年7月,61例髂骨翼肿瘤患者接受髂骨肿瘤切除重建手术。其中男38例,女23例;年龄12～78岁,平均43岁。根椐Enneking骨盆肿瘤分区：肿瘤累及Ⅰ区36例,Ⅰ、Ⅱ区17例,Ⅰ、Ⅳ区8例。肿瘤切除术后,检查骨缺损的大小,将钉棒系统应用于髂骨肿瘤切除后的缺损重建中。对于肿瘤累及Ⅳ区的患者,行钛网杯重建髋臼顶及全髋置换术。对于儿童患者,采用植骨或斯氏针＋骨水泥固定。结果61例髂骨肿瘤切除的患者中48例患者获得随访,随访时间为16个月至6年,平均43个月。其中33例存活,无肿瘤局部复发迹象;15例死亡。36例行Ⅰ区肿瘤切除的患者中,19．4％（7／36）出现局部复发;17例行Ⅰ、Ⅱ区肿瘤切刮、骨水泥填充、髋臼重建的患者中,35．3％（6／17）出现局部复发;8例行Ⅰ、Ⅳ区肿瘤切除的患者中,1例死于围手术期,50．0％（4／8）局部复发。功能结果：36例行Ⅰ区肿瘤切除的患者,术后有正常行走功能。17例行Ⅰ、Ⅱ区肿瘤刮除、骨水泥填充、髋臼顶重建、人工髋关节置换的患者,术后髋关节功能基本正常。结论可将钉棒系统应用于成人患者髂骨肿瘤切除后的缺损重建中,维持骨盆环的完整。对于儿童的髂骨肿瘤切除后的重建,应尽量采用比较简单的固定。可应用异体骨或自体髂骨（取自残存的部分髂骨）植于髂骨颈与骶骨翼之间,用加压螺丝钉固定。     

半骨盆置换术治疗骨盆恶性肿瘤的初步应用

目的探讨半骨盆置换术在骨盆恶性肿瘤广泛切除和功能性保肢手术中的应用。方法回顾中山大学附属第一医院骨肿瘤科2003年至2006年18例半骨盆切除和重建手术治疗案例，评估骨盆恶性肿瘤广泛切除和假体置换术的疗效和并发症。结果中山大学附属第一医院骨肿瘤科18例骨盆原发性恶性骨肿瘤患者，接受了骨盆Ⅰ区＋Ⅱ区＋（Ⅲ区）切除和人工半骨盆假体置换手术。患者平均年龄为19岁，病理类型包括12例骨肉瘤、3例尤文肉瘤和3例纤维肉瘤，外科分期均为ⅡB。患者经过术前肿瘤评估，MRI显示肿瘤尚未侵犯髂血管和坐骨神经，全身骨扫描未显示肿瘤跳跃或转移，肺部CT显示肿瘤无转移；同时患者接受两个循环规范化术前化疗后，初步化疗评估为良好。术前充分准备，常规切除骨盆Ⅰ区＋Ⅱ区＋（Ⅲ区），安装组合式半骨盆。组合式半骨盆假体设计突出骶骨座、无髂骨、可调髋臼及耻骨支。术中平均出血3000ml（1500～6000m1）。1例术后腓总神经损伤，5例有伤口并发症，其中1例感染和1例残腔愈合不良的患者接受了股外侧肌（皮）瓣转移，伤口均一期愈合。术后3周开始功能锻炼，2至3个月可扶拐行走。平均随访36．73个月（15-58个月），2例局部复发，3例死于远处转移，MSTS功能评分平均65％。结论在骨盆原发性恶性肿瘤的治疗中，广泛切除是治愈肿瘤的关键，应用半骨盆假体置换能有效重建骨骼缺损，联合肌皮瓣移植可以解决困难的伤口并发症，患肢功能可以接受。改进假体设计，改善患肢功能是今后努力的方向。     

计算机辅助骨盆恶性肿瘤的手术治疗

[目的]探讨应用计算机辅助的骨盆恶性肿瘤病例手术范围和植入假体设计的手术治疗后的临床效果.[方法]应用CT数据及快速成型技术,模拟骨盆肿瘤切除重建术,设计手术切除范围,制造病变骨盆精确模型和植入个体化假体;2003年6月～2007年7月,共有9位患者进行了肿瘤切除个体化人工半骨盆重建术,其中男3例,女6例,骨巨细胞瘤4例,脊索瘤2例,软骨肉瘤2例,骨肉瘤1例.根据Enneking骨盆肿瘤分区:Ⅱ区3例,同时累及Ⅱ区和Ⅲ区5例,同时累及Ⅰ区、Ⅱ区、Ⅲ区、骶骨区(Ⅳ区)1例.随访时间为12个月到5年.[结果]手术中病变切除彻底,假体安装顺利,术中平均出血4 700 ml,术后1例患者伤口内积血、感染,予以清创、灌洗引流后,选用敏感抗生素后痊愈.所有患者术后4～6周扶双拐部分负重行走,术后4个月逐渐弃拐,3例(33%)患者复发,其中骨肉瘤1例,术后18个月死于双肺转移;软骨肉瘤1例,术后13个月局部复发,术后17个月死亡;1例脊索瘤术后半年复发,二次手术,半年后再次复发,放弃治疗,3个月后死亡.1例术后2年时出现螺钉松动,患者可持拐行走.其余5例患者假体无松动,患侧髋关节和对侧髋关节对称.[结论]计算机辅助下的骨盆恶性肿瘤的手术范围设计,使切除边缘更彻底,个体化的人工半骨盆,与患者骨盆形状高度一致,保证了手术的顺利进行和良好临床效果,该技术在骨盆恶性肿瘤的切除及重建中有着良好的应用前景. 后4个月逐渐弃拐,3例(33%)患者复发,其中骨肉瘤1例,术后18个月死于双肺转移;软骨肉瘤1例,术后13个月局部复发,术后17个月死亡;1例脊索瘤术后半年复发,二次手术,半年后再次复发,放弃治疗,3个月后死亡.1例术后2年时出现螺钉松动,患者可持拐行走.其余5例患者假体无松动,患侧髋关节和对侧髋关节对称.[结论]计算机辅助下的骨 恶性肿瘤的手术范围设计,使切除边缘更彻底,个体化的人工半骨盆,与患者骨盆形状高度一致,保证了手术的顺利进行和良好临床效果,该技术在骨盆恶性肿瘤的切除及重建中有着良好的应用前景.     

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.     

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.     

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.     

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.