中华通用脊柱内固定装置的研制实验研究和临床应用

[目的]测试中华通用脊柱内固定装置(PRSS,ADS和PRFS)矫正脊柱侧弯效果和阐明矫正侧弯的生物力学机理。[方法]为克服使用欧美方法在治疗生长中儿童脊柱侧弯时需多次延伸内固定和广泛脊柱植骨融合,从而影响脊柱生长和运动等缺点,本院于1998年研制成中华通用脊柱内固定装置,从1998年10月~2003年12月作者用PRSS矫正各种类型脊柱侧弯183例生长中儿童侧弯,对其中66例随访2 a以上的特发性脊柱侧弯进行分析,其中男性29例,女性37例;手术时平均年龄12.15岁。并进行了生物力学测试和PRSS固定后的动物模型的椎体两侧的终板软骨中的X型胶原的测试,以阐明PRSS对侧弯的矫正作用和矫正的生物力学机理。[结果]脊柱侧弯由术前66.58°(40~110°)矫正至12.70°,平均矫正率68.86%,平均随访24.6个月,22例有平均6.5°丢失,其余无丢失。PRSS矫正节段脊柱平均增高11.13 mm,8例骨成熟后除去内固定,侧弯矫正维持良好,脊柱活动度接近正常。生物力学测试证明:在放置PRSS后,PRSS在凸侧的侧推力在脊柱两侧软骨终板上产生不对称应力,在侧弯凸侧产生压应力,而在凹侧出现张应力。并发现在凸侧椎体终板软骨上较之凹侧有更多的X型胶原表达,说明在压应力增加侧的椎体终板软骨细胞的分化、骨化或退变提前与加速,使该侧终板软骨的生长受到抑制,侧弯椎体两侧的不平衡生长达到脊柱侧弯矫正的目的,从分子生物学角度阐明PRSS的矫正机理。体外生物力学测试证明PRSS临床使用时不需植骨即能有效维持矫正。[结论]中华通用脊柱内固定装置是新型的我国首创的效果良好的脊柱侧弯矫正装置,特别适于生长中儿童的脊柱侧弯,其独有的优点为:手术时不需植骨融合,一次手术即能满意矫正脊柱侧弯及维持矫正,不需多次手术去延伸内固定。术后PRSS能随儿童脊柱生长而自动延伸,所以能有效防止躯干短小畸形和一部分“曲轴”现象。治疗完成后,脊柱屈伸活动功能接近正常。还能广泛用于治疗脊柱后凸畸形,前路脊柱旋转的矫正和固定,还可治疗脊柱滑脱和脊柱骨折,具有较高的社会效益和经济效益。     

后路半椎体切除短节段融合治疗先天性脊柱侧弯

[目的] 探讨单纯经后方人路半椎体切除后,行短节段椎弓根螺钉矫形固定对先天性脊柱侧弯的疗效.[方法] 2l例先天性半椎体畸形的患儿,单纯经后方入路切除半椎体,并一期行后路短节段椎弓根螺钉系统矫形固定和脊柱植骨融合术,比较术前、术后和最后一次随访脊柱全长正侧位x线片,测量并记录脊柱侧弯及后凸的Cobb's角.[结果] 本组病例脊柱畸形明显改善,冠状面,半椎体节段侧弯术前平均41.5°,术后15.1°,矫正率63.6%;最后一次随访时平均14.70,矫正64.6%;冠状面主侧弯术前平均46.9°,术后18.4°,矫正60.8%;最后一次随访时平均17.5.,矫正62.7%;矢状面,半椎体节段术前有15.4°后凸畸形,术后恢复至正常生理曲度范围.手术后头侧和尾侧代偿弯也得到明显改善.[结论] 单纯后方入路切除半椎体后行短节段椎弓根螺钉系统矫形内固定术,可满意地矫正先天性脊柱侧弯,在骨骼成熟之前进行治疗可有效地预防继发性的脊柱改变.     

生长发育中儿童脊柱侧弯治疗的理论与实践

目的 :从矫正机理上探讨适合于生长发育中儿童脊柱侧弯的手术治疗方法及本院研制的脊柱侧弯板棍系统 (Plate -RodSystemforScoliosis ,PRSS)临床应用的初步报告。方法 :设计新型的脊柱侧弯矫正装置———脊柱侧弯板棍系统 ,并随访从 1998年 9月～ 2 0 0 1年 10月期间应用PRSS装置及不植骨法治疗的生长发育中儿童脊柱侧弯共 2 2例(男 9例 ,女 13例 ) ,平均年龄 (10 .78± 3 .41)岁 ,其中特发性脊柱侧弯 16例 ,先天性脊柱侧弯 5例 ,神经纤维瘤病性脊柱侧弯 2例。结果 :侧弯矫正率为 (60 .0 9± 19.42 ) % ,随访时间平均 (12 .72± 6.79)个月 ,随访期间矫正丢失率为 (11.3 9±2 0 .0 0 ) % ,矫正节段长高 (4 .0 7± 3 .19)mm ,无严重并发症或“曲轴现象”发生。患儿骨发育成熟拆除内固定后 ,脊柱的活动和形态接近正常。结论 :在矫正侧弯的同时允许矫正范围内脊柱继续生长是治疗生长发育中儿童脊柱侧弯的较理想方法。初步应用结果显示PRSS是有效和可靠的方法。     

生长棒治疗早发儿童脊柱侧弯的关键问题

[目的]采用PRSS治疗的35例儿童脊柱侧弯Cobb角由术前平均66.58°矫正至平均22.70°,矫正率65.91%,最后随诊时,平均矫正度27.50°,无明显丢失,其中11例病例随诊时还发现侧弯度数进一步减轻。这一结果表明:PRSS具有明显的调控功能,不仅在手术时能立即满意的矫正畸形,还能在手术后继续治疗残存的脊柱侧弯,有效地控制术后残留脊柱侧弯的发展,矫正丢失很少。PRSS棒的下端能在术后随小儿生长向上拔伸,而且椎体的凹侧生长多于凸侧,使原来楔状变椎体重塑变回方形,代表PRSS所独有的术后自行矫正功能。用3-D CT检查显示侧弯凸侧椎间隙骨融合提前,凹侧则没有融合,仍有生长潜力。相比之下,国外所有生长棒技术的矫正力主要平均分布在矫正节段的上下端,而在侧弯的纵向负荷,主要集中在侧弯顶椎部位,不能逆转Hueter-Volkman定律效应:术后在侧弯的凹侧均形成椎弓根栓拉结构,无法向上拔伸,使凹侧半更多纵向生长,因而不能形成矫正侧弯的调控功能。     

不需植骨融合治疗生长中儿童脊柱侧弯的新装置

目的　为了避免需多次手术延伸内固定的缺点 ,研究自行设计的脊柱侧弯矫正装置板棍系统 (PRSS)治疗机制及其治疗生长中儿童特发性脊柱侧弯的疗效。方法　用PRSS矫治 34例逐渐加重的生长中儿童特发性脊柱侧弯 ,通过生物力学测试及动物模型X型胶原测试分析PRSS的矫治机制。结果　侧弯术前平均 6 3 6 3°± 19 80°(4 0°～ 110°) ,术后平均 2 3 91°± 15 6 3°(6°～ 6 6°) ,平均矫正率 6 4 0 6 %± 17 0 2 % ,最好者为 87 2 7%。随诊 2 8例 ,平均随诊 2 9 6个月 ,有 15例平均矫正丢失 8°,其余病例无丢失。手术矫正部位脊柱继续生长 ,平均13 5mm ,无严重并发症。放置PRSS后 ,在脊柱侧弯凸侧产生压应力 ,在凹侧产生张应力 ,而不需要植骨。动物试验X型胶原测试证实 :在压应力增力侧的椎体终板软骨退变加速 ,从而抑制该侧生长 ,而张力侧则不受影响 ,两侧不平衡生长达到脊柱变直的目的。结论　PRSS矫正装置能随脊柱生长自动延伸 ,在治疗脊柱侧弯时不需植骨融合 ,通过一次手术即能满意矫正生长中儿童的脊柱侧弯 ,并在生长过程中维持其矫正 ,具有特殊的生物力学矫正能力。PRSS是治疗脊柱侧弯特别是生长中儿童脊柱侧弯的有效方法     

板一根系统（PRSS）对生长中儿童和成人脊柱侧弯矫治的早期结果

目的研究新型脊柱侧弯矫正装置-板棍系统PRSS(Plate-RodSpinalSystem)对生长发育中儿童和成人的脊柱侧弯的矫治效果及治疗原理。方法从1998年9月～1999年6月对35例脊柱侧弯使用PRSS矫治。其中先天性脊柱侧弯10例,特发性脊柱侧弯22例,其它4例平均年龄15.6岁(3～34岁)。术前平均畸形为65.5°(40°～103°)。所有病例均进行术前后X线检查分析。PRSS矫正力由弹力板棍提供,不需植骨融合,允许矫正节段脊柱继续生长。结果平均随诊6.9个月,侧弯畸形度由术前平均68.6°矫正至31.7°,平均矫正率53.8%,最好者87.2%,平均身高增加5cm,矫正节段平均增高5mm。结论PRSS是新型有效的脊柱侧弯矫正装置,特别适于生长发育中儿童的脊柱侧弯,其矫正方式和原理均与国内外流行方法不同,具有不易发生截瘫和脱钩的优点,为脊柱侧弯的治疗开辟了一条新路。     

生长棒治疗生长中儿童脊柱侧弯时调控功能的X线研究

[目的]探索能反映治疗生长中儿童侧弯生长捧调控作用的X线检查方法,并验证板-棍系统(plate-rod system for scoliosis,PRSS)的调控能力。[方法]对31例置入PRSS的早发型脊柱侧弯进行至少2年的随访,收集术前、术后即刻、术后每次随访的站立位全脊柱正侧位X线片,测量其Cobb角和能反映顶椎楔形变程度的顶椎楔变角(apical vertebral wedge angle,AVWA),分析不同侧弯类型和不同手术时年龄组术后生长发育期间的顶椎椎体两侧生长速度差异、变化趋势与调控作用的关系。[结果]术前Cobb角平均63.74°±20.99°,术后矫正为25.38°±14.76°,末次随访时为31.68°±19.53°,无明显矫正丢失(P>0.05)。术后即刻AVWA平均13.74±5.88°,末次随访时平均8.74°±5.08°,平均减小5.00°±4.46°,差异有统计学意义(P<0.05)。AVWA的度数在术后总体呈下降趋势,反映侧弯椎体凹侧的生长速度超过凸侧。先天性脊柱侧弯的AVWA虽然在术后的测量起始阶段大于特发性脊柱侧弯的AVWA,但两者角度在术后的生长期间,总体都呈减小趋势,只是前者波动较明显。5岁前接受PRSS治疗的脊柱侧弯,其初始AVWA较小,且术后AVWA减小过程更平稳。[结论]测量术后生长中儿童侧弯的顶椎楔变角(AVWA),发现楔形变程度变小,是由于PRSS放置后使顶椎体两侧不对称生长发生了逆转,使凹侧生长速度超过凸侧,椎体两侧高度差减小造成的,反映了PRSS对儿童脊柱侧弯椎体两侧生长速度的调控作用。测量比较AVWA的变化是评价生长棒调控效果的一种可靠的检查方法。     

肋骨结构性支撑植骨在脊柱侧凸前路矫形手术中应用的长期随访

[目的]评价肋骨结构性支撑植骨在青少年特发性脊柱侧凸前路矫形融合手术中应用的长期随访结果.[方法]回顾性分析术后随访时间超过4年的青少年特发性脊柱侧凸前路矫形手术病例30例,男3例,女27例;年龄12～ 17.5岁,平均14.3岁.侧凸类型包括PUMC Ⅰ b型5例、Ⅰc型5例、Ⅱd1型20例.全部病例均行前路矫形融合手术,植骨方式采用自体肋骨结构性支撑植骨.术前、术后及随访时摄脊柱站立位X线片,测量冠状面及矢状面Cobb角,并观察植骨融合情况,有无假关节形成及内置物并发症.[结果]随访4～10.2年,平均6.3年.融合弯冠状面矫形率术后平均为75.1％,末次随访时矫形丢失平均4.6°;固定融合节段冠状面矫形率术后平均为93.2％,末次随访时丢失平均2.1°;固定融合节段矢状面Cobb角术前与术后比较无显著性差异,末次随访时矫形丢失平均3.1°.13例胸腰段后凸患者术前后凸平均8.3°,术后矫正为前凸平均5.6°,末次随访时保持前凸平均3.7°.全部病例末次随访时均未见假关节形成或内置物并发症.[结论]肋骨结构性支撑植骨在青少年特发性脊柱侧凸前路矫形融合手术中能获得并维持良好的冠状面及矢状面矫形,且融合率高、远期矫形丢失少,是一种可靠、有效的植骨方法.     

脊柱板-棍系统与钉棒系统在重度脊柱侧凸矫形中的应用及效果

[目的] 评价脊柱板-棍系统(plate-rod spinal system,PRSS)及钉棒系统治疗重度脊柱侧凸的疗效.[方法] 2001～2007年本科收治25例重度脊柱侧凸患者,按矫形器械分为PRSS系统治疗组和钉棒系统治疗组.采用PRSS系统治疗12例,男7例,女5例;平均15.2岁;其中先天性脊柱侧弯1例,神经纤维瘤型脊柱侧弯1例,特发性脊柱侧弯10例.钉棒系统治疗13例,男9例,女4例;平均17.6岁;其中特发性脊柱侧弯6例(1例术前不全瘫),先天性脊柱侧弯3例,神经纤维瘤型脊柱侧弯3例,重度脊柱侧弯翻修术1例.两组病例采用的术式包括术前牵引后,前路松解联合后路矫形;前路松解联合后路矫形术;一期单纯后路矫形术和后路松解截骨矫形术.术后根据畸形矫正及并发症发生情况评估两种内固定系统的疗效.[结果]两组病例均顺利完成手术,无死亡及严重手术并发症出现.PRSS治疗组平均手术时间3.6 h,术中平均出血量930ml,术后平均随访56.7个月,主侧弯Cobb角由术前平均98°(86°～135°),矫正至术后平均59°(32°～76°),矫正率平均57%,出现断棒3例,脱钩1例,皮肤破溃或皮下滑囊形成11例.钉棒系统治疗组平均手术时间4.6 h,术中平均出血量1420 ml,术后平均随访7.8个月.主侧弯Cobb角由术前平均108°(93°～159°),术后矫正至平均54°(30°～105°),矫正率平均66.3%.矢状面后凸从术前平均116°(90°~155°)矫正至术后平均34°(20°～45°),发生肠系膜上动脉综合征1例,术后肋间神经痛1例,术后双下肢-过性麻木2例,-过性肌力减退1例.[结论]术前正确评估判断是前提;手术彻底松解是基础,椎弓根钉置入、矫形靠经验,准确操作及诱发电位监控是安全保障.PRSS系统操作简便、经济,与钉棒系统相比,矫正效果差,并发症较多.     

一期后路楔形截骨治疗青春期后严重先天性脊柱侧弯

[目的]介绍一期后路楔形截骨治疗青春期后严重的先天性脊柱畸形的安全操作及探讨其融合固定范围的选择.[方法]自2000年2月～2006年7月对16例青春期后严重的先天性脊柱侧弯采用一期后路楔形截骨内固定矫形.男10例,女6例;年龄16～29岁,平均21.4岁.其中单纯半椎体11例,半椎体合并对侧骨桥或肋骨融合5例,既往有脊柱矫正手术史者2例.术前脊柱侧凸Cobb' s角64°～108°,平均84.7°;脊柱后凸角28°～91°,平均52.6°;躯干偏移3～23.6 mm,平均15.4 mm.CT或MRI显示椎管内骨性分隔2例.[结果]手术时间平均231 min,术中出血平均1 400 ml.术后平均随访2年6个月.固定融合节段8～14个椎体,平均10.6个.侧凸Cobb' s角18°～47°,平均38.5°,平均矫正率54.5%;后凸Cobb' s角15°～40°,平均27.7°,平均矫正率47.4%;术后躯干偏移0～11.4 mm,平均为4.6 mm.侧、后凸和躯干偏移无明显矫正丢失.手术并发症包括术中椎弓根骨折2例;L1神经根损伤1例;肠系膜上动脉综合征1例;术后切口渗液1例.[结论]采用一期后路楔形截骨内固定治疗青春期后严重的先天性脊柱侧弯是一个安全、可靠的方法,矫形效果满意,远期疗效可靠.     

Reduction of Plasma Fibrinogen, Immunoglobulin G, and Immunoglobulin M Concentrations by Immunoadsorption Therapy with Tryptophan and Phenylalanine Adsorbents

Abstract Immunoadsorption (1A) therapy with tryptophan (TR-350) or phenylalanine (PH-350) adsorbents has been used to reduce the concentration of serum antibodies in human lymphocyte antigen (HLA)-immunized patients. Other forms of plasma purification have been reported to reduce the level of fibrinogen, which affects the blood properties. In this study we investigated the effects of IA therapy using both adsorbents on plasma fibrinogen and immunoglobulins G and M in 13 patients (8 patients were treated with TR-350, and 5 patients were treated with PH-350). During each session 1 plasma volume (2.8 ± 0.4 L of plasma) was processed through the immunocolumn and then returned to the patient together with the blood cells. Compared with the pretreatment values, the plasma fibrinogen, IgG, and IgM concentrations were significantly reduced after IA therapy (p < 0.01 for TR-350; p < 0.04 for PH-350). There was a positive correlation between the degree of reduction of plasma proteins and the number of IA treatments given. A nonpara-metric test (Wilcoxon's signed-rank test or the Mann-Whitney test) was used for statistical analysis. We conclude from our study that IA therapy effectively lowers the plasma levels of fibrinogen, IgG, and IgM and thus can be considered a valuable alternative to other blood purification methods.     

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.     

The multiply injured child

Blunt trauma is the principal cause of childhood death in many developed countries. This review outlines the differences between adults and children with respect to resuscitation and treatment of orthopaedic injuries in a child with polytrauma. Recent advances in techniques of fracture stabilization are reported.     

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.     

Development of Selective Low-Density Lipoprotein (LDL) Apheresis System: Immobilized Polyanion as LDL-Specific Adsorption for LDL Apheresis System

Abstract: Low-density lipoprotein (LDL) is widely recognized as one of the major risk factors for developing coronary heart diseases. Despite intensive development of LDL-lowering drugs, there still exist those patients with refractory hyperlipidemia whose plasma LDL levels are not sufficiently lowered by drugs. LDL apheresis, direct removal of plasma LDL from circulating blood, is thought to be the most promising treatment for such refractory patients. Various techniques, such as the use of an im-munoadsorbent utilizing an anti-LDL antibody, have been used in an attempt to achieve the selective removal of LDL. However, none were widely used because of complications, poor selectivity, and so forth. To establish a safe and effective LDL apheresis system, we chose a synthetic affinity adsorbent as the LDL-removing device. Synthetic polyanion compounds were used as the affinity ligands for LDL adsorbent to simulate the anion-rich sequence of LDL binding sites in the human LDL receptor. Among various polyanion compounds, those polyanions with sulfate or sulfonate groups and hydrophilic backbone were found to have strong affinity for LDL. In contrast, polyanions with carboxyl groups showed poor affinity. Dextran sulfate (DS) was selected as the affinity ligand of LDL adsorbent for its high affinity and low toxicity. The influence of its charge density and molecular weight on its affinity for LDL was suitable. The affinity rapidly increased as the charge density increased, then, reached a constant value. Little affinity was found for either the DS monomer (glucose sulfate) or DS with a molecular weight higher than 10⁴ daltons whereas DS with molecular weights in the midrange showed strong affinity. DS with a midrange molecular weight was immobilized on cellulose hard gel to give LDL adsorbent clinical application. The adsorbent demonstrated an excellent selectivity for LDL and very low density lipoprotein (VLDL) in vitro. Adsorption of high-density lipoprotein and major plasma proteins was almost negligible. Additional study of the LDL-binding mechanism revealed that DS directly interacts with positively charged sites on LDL, which demonstrates that the nature of the interaction is the same as that of LDL receptor. An LDL adsorption column (Liposorber) packed with an LDL adsorbent and polysulfone hollow-fiber plasma separator (Sulflux) was developed as an efficient LDL apheresis system. Clinical investigation proved that this system is capable of intensively lowering the plasma LDL level without affecting major plasma components.     

Artificial organs 2010: a year in review

In this Editor's Review, articles published in 2010 are organized by category and briefly summarized. As the official journal of The International Federation for Artificial Organs, The International Faculty for Artificial Organs, and the International Society for Rotary Blood Pumps, Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level."Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide such meaningful suggestions to the author's work whether eventually accepted or rejected and especially to those whose native tongue is not English. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, Wiley-Blackwell, for their expert attention and support in the production and marketing of Artificial Organs. In this Editor's Review, that historically has been widely received by our readership, we aim to provide a brief reflection of the currently available worldwide knowledge that is intended to advance and better human life while providing insight for continued application of technologies and methods of organ Replacement, Recovery, and Regeneration. We look forward to recording further advances in the coming years.     

Avaliação do clube de revista de anestesiologia por meio de mudanças semânticas

Background and objectives

The interactive approach of a journal club has been described in the medical education literature. The aim of this investigation is to present an assessment of journal club as a tool to address the question whether residents read more and critically.

Methods

This study reports the performance of medical residents in anesthesiology from the Clinics Hospital – University of São Paulo Medical School. All medical residents were invited to answer five questions derived from discussed papers. The answer sheet consisted of an affirmative statement with a Likert type scale (totally disagree–disagree–not sure–agree–totally agree), each related to one of the chosen articles. The results were evaluated by means of item analysis – difficulty index and discrimination power.

Results

Residents filled one hundred and seventy three evaluations in the months of December 2011 (n = 51), July 2012 (n = 66) and December 2012 (n = 56). The first exam presented all items with straight statement, second and third exams presented mixed items. Separating “totally agree” from “agree” increased the difficulty indices, but did not improve the discrimination power.

Conclusions

The use of a journal club assessment with straight and inverted statements and by means of five points scale for agreement has been shown to increase its item difficulty and discrimination power. This may reflect involvement either with the reading or the discussion during the journal meeting.     

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.