生长撑开型非融合矫形技术治疗早发性脊柱侧凸的远期疗效

目的探讨完成生长撑开型非融合矫形技术(growth friendly non-fusion technique,GF)治疗早发性脊柱侧凸(early-onset scoliosis,EOS)患者的远期随访疗效。方法回顾性分析2008年8月至2019年10月完成GF治疗的26例EOS患者,男12例、女14例,初次手术时年龄(7.2±2.4)岁。16例患者采用传统生长棒技术治疗,10例患者接受纵向可撑开型人工钛肋技术(vertical expandable prosthetic titanium rib,VEPTR)治疗。所有患者均接受2次以上的撑开手术且完成生长棒及VEPTR治疗后随访时间均超过2年。收集患者初次手术前、术后即刻、完成GF治疗时以及末次随访时的临床资料和影像学资料,同时记录手术相关并发症的发生情况。结果26例患者共接受145次撑开手术,撑开次数为(5.6±2.1)次。患者完成GF治疗时年龄(12.6±1.6)岁,GF治疗撑开时间为(4.7±1.4)年,完成GF治疗后随访时间为(2.9±0.9)年。内固定初次置入术后主弯Cobb角由术前81.2°±17.3°明显降低至41.1°±13.1°(t=8.124,P<0.001),末次撑开时增加至48.8°±15.4°。16例患者在末次撑开手术后再行终末融合手术,主弯Cobb角由末次撑开时52.8°±16.1°降低至45.4°±14.8°(t=2.415,P=0.035),矫正率为14.1%±9.4%;余10例患者未行终末融合手术而直接进行长期随访。患者完成GF治疗时及末次随访时主弯Cobb角分别为44.9°±16.2°和45.2°±15.6°;末次随访时与术前比较,主弯Cobb角矫正率为44.3%±15.5%。内固定置入术后胸椎高度及脊柱高度均较初次手术前明显增加,生长棒撑开期间胸椎高度(T1~T12)和T1~S1高度分别增加(3.3±0.9)cm和(5.6±1.9)cm,每次撑开手术后胸椎高度和T1~S1高度分别可获得(0.6±0.3)cm和(1.0±0.4)cm的增加。术后14例患者发生36例次并发症,撑开期间13例患者共发生27例次并发症,完成GF治疗后的随访期间共8例患者发生9例次并发症。结论GF矫形技术可以有效地控制EOS患者畸形的进展,同时维持躯干的生长发育,完成GF治疗后并发症发生率较撑开期间明显降低,但反复撑开后行终末融合手术的矫正率较低。     

双生长棒固定治疗重度早发型脊柱侧凸的疗效分析

目的:分析应用双生长棒固定治疗重度早发型脊柱侧凸患者的临床效果,评估其临床应用的临床疗效及安全性。方法:2007年1月~2015年6月我科收治的重度早发型脊柱侧凸并行双生长棒矫形术治疗的患者25例(男12例,女13例),初次术前主弯Cobb角均大于80°且Risser征≤Ⅰ级。测量初次手术前、手术后以及末次随访时冠状面主弯Cobb角、T1~S1高度、矢状面最大后凸角,分析患者的矫形效果及脊柱高度变化。同时收集患者初次术前、初次术后6月及末次随访的肺功能指标及胸部CT,测量患者初次术前、初次术后及末次随访时的肺容积,分析患者肺功能变化情况。结果:入组患者初次术前年龄7.8±1.4岁(5~9岁),随访时间40.3±13.1个月(22~54个月),撑开手术次数平均3.2次(3~7次)。冠状面主弯Cobb角初次术前为96.7°±15.5°,初次术后改善为50.7°±16.1°,至末次随访时改善为40.3°±10.9°;T1~S1高度由初次术前23.2±3.5cm增至初次术后31.1±3.8cm,而末次随访时增至36.5±4.2cm,矢状面最大后凸角初次术前为73.2°±18.9°,初次术后改善为47.7°±15.8°,末次随访时改善为41.2°±11.6°。患者末次随访时肺功能指标及胸廓容积较初次术前明显改善。入组患者共9例出现并发症,其中内固定相关并发症7例(8次),近端交界性后凸4例。结论:双生长棒应用于重度早发型脊柱侧凸患者的治疗可以获得良好的矫形效果,有助于改善和维持患者肺功能,但仍存在一定的手术并发症风险。     

生长阀双棒内固定技术治疗儿童严重脊柱侧凸的初步临床应用

目的 评价生长阀双棒内固定技术治疗早发的儿童脊柱侧凸的初步应用结果 .方法 2004年11月至2009年3月行生长阀双棒内固定技术治疗儿童脊柱侧凸11例,男1例,女10例;年龄2.1～10.9岁,平均6.1岁.Risser征均为0级.胸椎侧凸8例,胸腰椎侧凸3例;先天性脊柱侧凸10例,神经肌肉性脊柱侧凸1例.10例采用Isola生长阀固定,1例采用TSRH生长阀固定.撑开1～4次,平均1.8次.随访4.2～38.1个月,平均17.3个月.结果 术前主弯Cobb角67.64°±11.43°,胸后凸31.00°±22.40°,躯干偏移(2.00±1.73)cm,T1S1高度(25.47±6.16)cm;初次术后主弯Cobb角34.64°±8.26°,胸后凸23.00°±8.06°,躯干偏移(1.49±1.31)cm,T_1～S_1高度(28.84±5.69)cm;末次术后主弯Cobb角36.82°±11.76°,胸后凸27.18°±8.97°,躯干偏移(1.11±1.29)cm,T_1～S_1高度(31.29±4.50)cm.术前、初次术后和末次术后主弯侧凸角比较差异有统计学意义.初次手术矫止率47.15%±16.48%,T_1～S_1高度增加(3.37±1.62)cm;末次手术矫正率44.73%±19.43%,T_1～S_1高度增加(5.82±2.21)cm.治疗期间T_1～S_1每年平均生长1.6 cm(1.1～2.7 cm).5例出现并发症:3例脱钩,1例椎弓根螺钉脱出,1例断棒.结论 生长阀双棒内固定技术允许脊柱纵向生长,同时起到矫形和控制畸形发展的作用,但术后并发症发生率较高.     

生长棒治疗1型神经纤维瘤病早发性脊柱侧凸

目的:观察生长棒治疗1型神经纤维瘤病早发性脊柱侧凸的有效性。方法:回顾性分析13例生长棒治疗的1型神经纤维瘤病早发性脊柱侧凸患者的临床资料,其中男8例,女5例;年龄5~10岁(7.5±2.1岁)。随访时间2~10年(5.1±2.8年)。生长棒置入术后每6个月撑开1次。影像学测量指标包括侧凸Cobb角、后凸角、躯干高度(T1~S1),并统计手术并发症。结果:术前侧凸Cobb角69.0°±21.2°(43°~90°),末次随访25.3°±15.0°(12°~45°),矫正率63.3%。躯干高度术前323.0±29.1mm(288~355mm),末次随访400.5±25.7mm(361~430mm),躯干高度增加77.1±18.3mm,每年继续生长11.7±3.3mm。9例患者出现并发症,并发症发生率69.2%。共发生并发症16例次,包括内置物失败9例次(56.3%),交界区后凸5例次(31.3%),内置物外露1例次(6.2%),深部感染1例次(6.2%)。9例后凸角50°患者中6例(66.7%)出现并发症,4例后凸角≥50°患者中3例(75%)出现并发症,两组并发症发生率差异无统计学意义(χ~2=0.123,P=0.726)。结论:生长棒治疗1型神经纤维瘤病早发性脊柱侧凸可有效改善脊柱畸形,并且保持躯干的继续生长;伴有严重后凸并未增加术后并发症的发生率。     

生长棒治疗伴椎管内异常的早发性脊柱侧凸的疗效及安全性分析

目的 :探讨生长棒治疗伴椎管内异常的早发性脊柱侧凸(early-onset scoliosis,EOS)的疗效及安全性。方法:2009年11月～2016年8月共73例EOS患儿于我院行生长棒治疗,其中伴椎管内异常的患儿中符合纳入标准的共11例,男2例,女9例,初次就诊年龄为8.2±1.3岁(6～10岁)。先天性脊柱侧凸9例,神经肌源性脊柱侧凸2例。伴单纯脊髓空洞3例,单纯脊髓拴系1例,单纯脊髓纵裂3例,脊髓空洞合并脊髓拴系2例,脊髓拴系合并脊髓纵裂1例,脊髓纵裂合并脊髓空洞、脊髓拴系1例。术前2例患儿存在神经系统症状,包括Honor综合征1例和神经源性膀胱伴会阴部麻木1例,其余患儿无神经系统损害表现。记录生长棒置入手术前后和末次随访时患儿站立位主弯Cobb角和T1-S1高度,采用配对t检验比较术前、术后及末次随访时的差异。记录术中及随访期间的神经及内固定并发症。结果:11例患儿共进行45次手术治疗,其中包括生长棒置入11次、生长棒撑开34次。平均撑棒间隔时间为11.2±1.1个月(8～12个月),总随访时长为39.7±11.6个月(24～72个月)。11例患儿生长棒置入术前主弯Cobb角为85.2°±23.4°,生长棒置入术后为51.4°±18.9°,末次随访时为52.8°±19.4°;生长棒置入术前站立位T1-S1高度为24.6±3.9cm,初次术后和末次随访时分别为28.9±3.4cm和31.9±3.4cm。初次术后和末次随访时主弯Cobb角和T1-S1高度与初次术前比较均有统计学差异(P0.001)。11例患儿中,共3例患儿出现5次并发症。1例患者在第3次撑开时发现冠状面失衡伴骨盆倾斜和钉棒松动,撑开同时行翻修术;1例第3次撑开后随访中发现下端椎螺钉松动合并矢状面失衡,10个月后行终末期融合手术;1例第2次撑开后发现近端交界性后凸,随访中无明显进展。所有患儿在生长棒置入和后续多次撑开及随访过程中均未观察到新发神经并发症。结论:对于伴有椎管内异常的EOS患儿,若无明显神经损害或神经损害相对稳定,行生长棒置入及多次撑开是相对安全有效的。     

凹侧双棒撑开治疗重度早发性脊柱侧凸的中期疗效

目的评估后路凹侧双棒撑开技术治疗重度早发性脊柱侧凸患儿的中期疗效,并分析相关并发症。方法回顾性研究2007年6月至2013年12月于我中心接受凹侧双棒撑开技术治疗的52例重度早发性脊柱侧凸患儿,锚定点均采用椎弓根螺钉固定。通过复习病例资料,对年龄、撑开次数、撑开间隔时间以及并发症进行记录;同时对影像学资料进行测量分析,测量指标包括侧凸Cobb角、胸椎后凸Cobb角和T1~S1长度,对畸形的矫正情况进行评估。结果根据患儿平均撑开间隔时间,将病例分为两组:A组有32例,男9例,女23例,初次手术年龄平均(7.4±1.1)岁(4~10岁),患儿共接受148次手术,手术间隔时间平均12.6个月(4~18个月),随访时间平均60.7个月(30~102个月),冠状面主弯Cobb角术前(109±23)°,术后(55±16)°,末次随访时(46±12)°;T1~S1长度平均年增长率为1.9cm/年。B组有20例,男6例,女14例,初次手术年龄平均(7.7±1.3)岁(5~10岁),患儿共接受54次手术,手术间隔时间平均26.4个月(12~72个月),随访时间平均61.5个月(29~108个月),冠状面主弯Cobb角术前(104±19)°,术后(51±13)°,末次随访时(62±17)°;T1~S1长度平均年增长率为1.19cm/年。末次随访时,A组在侧凸、胸椎后凸、躯干偏移矫正方面优于B组,差异有统计学意义(P0.05),但T1~S1长度,差异无统计学意义(P0.05)。A组有7例患者(21.9%)共发生9例次并发症,B组有12例患者(60%)共发生15例次并发症。结论对于重度早发性脊柱侧凸,采用凹侧双棒撑开技术是一种有效的选择。缩短撑开间隔时间,可减少并发症的发生,并可获得更好的脊柱畸形的矫正与控制。     

双生长棒技术治疗早发性脊柱侧凸的中期疗效

目的:评估双生长棒技术治疗5岁以下早发性脊柱侧凸患儿的中期疗效,分析相关并发症原因。方法:回顾性研究2004年2月~2012年6月于我科接受双生长棒技术治疗的14例(男4例,女10例)早发性脊柱侧凸患儿;平均年龄3.5±1.2岁(2~5岁)。通过复习病历,对年龄、撑开次数以及并发症进行记录;同时对影像学资料进行测量分析。测量指标包括侧凸Cobb角、胸后凸、腰前凸、T1-S1距离以及内固定的长度,对畸形的矫正情况以及脊柱、胸廓的生长指标——坎贝尔的空间供肺比值(Campbell′s space available for lung ratio,SAL)进行评估。结果:所有患儿平均随访时间为54.6±22.4个月(24~100个月)。14例患儿共接受99次手术,其中85次为撑开术,平均每例患者经历6.1次撑开术。冠状面主弯Cobb角术前73.8°±19.1°,术后35.8°±12.8°,末次随访时34.5°±16.3°。T1-S1距离从术前23.9±4.2cm增至术后27.1±4.8cm,末次随访时为33.6±5.2cm,平均年增长率为1.61cm/y。内固定长度初次手术术后为23.1±5.3cm,末次随访时为28.0±6.2cm。SAL术前为0.90±0.10,术后改善至0.92±0.09,末次随访时为0.96±0.11。有4例患者发生8例次并发症,主要为内固定相关(7例次)并发症,均在撑开手术同时进行翻修;无感染以及神经系统并发症发生。结论:双生长棒技术用于治疗5岁以下、保守治疗无效的进展性早发性脊柱侧凸患儿,不仅可以有效地控制脊柱畸形的进展,保留脊柱的生长潜能,而且对患儿胸廓畸形也具有一定的矫正作用;尽管该技术内固定失败发生率较高,但通过翻修手术仍可以获得满意的临床疗效。     

后路单侧经椎弓根半椎体截骨治疗青少年先天性脊柱侧凸

目的评估后路经椎弓根截骨矫形部分半椎体保留治疗先天性半椎体所致脊柱侧凸畸形的临床疗效。方法共18例先天性半椎体合并脊柱侧凸患者纳入随访研究,平均年龄16.17岁（14～21岁）,术前测量半椎体所致脊柱畸形的节段性主弯Cobb角45.39°±6.81°,头侧代偿弯Cobb角27.5°±2.71°,尾侧代偿弯Cobb角为26.44°±6.85°,顶椎偏距为4.28±0.58cm,节段性后/前凸角度为14.11°±18.07°。所有病例均采用后路一期经半椎体椎弓根截骨,双侧固定矫正侧凸畸形。随访时间为14.17±6.56个月。综合评估影像学、临床疗效以及并发症的情况。结果手术时间为2.82±0.74h,术中失血量317.22±65.15ml。术后节段性主弯Cobb角为11.33°±4.68°,矫正34.06°±7.88°,末次随访14.61°±4.96°;头侧代偿弯Cobb角为8.72°±1.44°,矫正18.78°±3.17°,末次随访18.78°±3.17°;尾侧代偿弯Cobb角为7.98°±1.82°,矫正18.47°±5.83°,末次随访18.47°±5.83°;节段性后/前凸角为-1.94°±12.35°,矫正14.94°±10.18°,末次随访-1.5°±12.67°。顶椎偏距的矫正为2.31±0.52cm,末次随访2.1±0.24cm。术中没有血管、神经损伤、骨折等重大并发症发生,术后没有发生冠状面和矢状面的失代偿。结论后路半椎体经椎弓根截骨矫形能有效矫正轻、中度先天性半椎体所致脊柱侧凸畸形,缩短手术时间,创伤小,减少术中失血量,矫形效果满意,所选病例骨骼发育相对成熟者,避免矫形丢失。     

经伤椎内固定椎间椎体内打压植骨治疗胸腰椎骨折

目的探讨后路经伤椎短节段复位内固定联合椎间椎体打压植骨治疗胸腰椎骨折的疗效。方法采用经伤椎后路复位短节段内固定、椎间椎体内植骨治疗21例胸腰椎骨折患者。根据术前、术后1周及末次随访时正、侧位X线片评判术后伤椎椎体前缘高度、后凸Cobb角恢复及内固定失败和骨融合情况。结果患者均获随访,时间12~32个月。未见断钉断棒及内固定松动。伤椎及椎间植骨均获骨性愈合。伤椎椎体前缘高度:术后1周为95.1%±3.2%,末次随访时为93.9%±3.6%,均较术前39.6%±10.3%明显改善(P0.01)。损伤节段后凸Cobb角:术后1周为12.2°±2.9°,末次随访时为12.9°±3.5°,均较术前(33.7°±6.2°)明显恢复(P0.01)。末次随访时与术后1周比较,伤椎椎体前缘高度和Cobb角均无明显变化(P0.05)。结论后路经伤椎短节段内固定联合椎间及伤椎打压植骨治疗胸腰椎骨折,重建了椎间和椎体的稳定性,有助于减少术后内固定失败及矫正丢失。     

先天性脊柱畸形手术治疗的总体疗效与并发症

目的:评估先天性脊柱畸形手术治疗的总体效果和并发症。方法 :回顾性分析2007年4月～2018年1月本团队手术治疗的431例先天性脊柱侧凸患者,其中男158例,女273例,平均年龄14.9±6.2岁。术前均行全脊柱CT平扫和全脊柱MRI,排查椎管内畸形情况;心脏彩超和腹部B超检查排除其他内脏畸形。手术方式包括:生长撑开型非融合矫形技术(包括生长棒和人工钛肋)治疗40例,后路半椎体切除短节段固定融合术48例,后路长节段矫形固定融合术(可含1、2级截骨)89例,后路截骨(3级及以上截骨)矫形长节段固定融合术254例。每位患者均于术后3个月、6个月、1年和2年及以上时间进行随访。术前、术后及随访时均拍摄站立位全脊柱正侧位X线片,测量脊柱侧凸Cobb角、矢状面平衡(sagittal vertical axis,SVA)及冠状面平衡(C7PLCSVL)。统计手术时间、术中出血量和手术并发症情况。结果:431例患者合并椎管内畸形351例次、合并其他内脏畸形24例次。平均手术时间为412.4±150.6min,平均术中出血量为1879.9±1727.6ml,平均随访时间48.7±9.3个月。脊柱侧凸术前平均Cobb角为68.88°±27.55°,术后平均Cobb角为28.86°±18.90°,末次随访时30.77°±19.80°;SVA术前平均为22.15±19.37mm,术后24.15±22.22mm,末次随访时19.75±16.06mm;C7PL-CSVL术前平均为17.37±15.47mm,术后21.95±47.29mm,末次随访时13.03±12.39mm,末次随访的脊柱侧凸Cobb角和C7PL-CSVL与术前比较均有统计学差异(P0.05)。术后肺部并发症49例、神经并发症30例、内固定相关并发症20例、术后感染10例以及脑脊液漏8例。结论:先天性脊柱侧凸手术矫形效果良好,但手术相关并发症风险较高,术后并发症总体发生率为30.16%,其中肺部并发症和神经并发症最为常见。     

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.