经椎弓根部位椎体楔形截骨治疗骨质疏松性脊柱陈旧性骨折伴后凸畸形

目的:探讨后路经椎弓根部位截骨矫形术治疗骨质疏松性脊柱陈旧性骨折伴后凸畸形临床效果。方法:2009年7 月至2014 年2 月采用后路经椎弓根截骨矫形治疗26例骨质疏松性陈旧性脊柱骨折伴后凸畸形的患者,其中男10例,女16 例,年龄55～75岁,平均67岁;胸椎1例,胸腰椎21例,腰椎4例;共29个椎体骨折,单椎体骨折23例,双椎体骨折3例;术前后凸Cobb 角为32°～51°,平均(42.00±4.75)°;VAS 评分6～9 分,平均(8.40±0.75)分,脊髓功能按Frankel 分级:D 级4例,E 级22 例。记录术中出血量、手术时间及围手术期并发症,采用X 线片观察Cobb 角改善情况,应用VAS 评分评价疼痛缓解情况,应用Frankel 分级评价神经功能恢复情况。结果:26例患者手术时间120～175 min,平均155 min;术中出血量800～1 500 ml,平均1 100 ml.术后第2天时Cobb 角5°～15°,平均(9.60±2.50)°,较术前明显改善(P <0.05),改善率76%;VAS 评分1～5 分,平均4.00±1.00,较术前明显改善(P <0.05);脊髓功能Frankel 分级1例由E 级变为C级,其余未有加重情况。术后随访3～24个月,平均16.4个月。末次随访时Cobb 角5°～19°,平均(11.00±3.50)°,VAS 评分1～6 分,平均(4.40±1.25)分,术后脊髓功能Frankel 分级由E 级变为C级1例,恢复至D级,余无加重病例。1 例患者术后3个月出现固定节段下位椎体骨折,1 例患者术后5个月出现固定节段上位相邻节段椎体骨折,均予对症、抗骨质疏松治疗后胸背痛症状缓解;影像学可见植骨融合,未见内固定松动及断裂。结论:经椎弓根截骨矫形术治疗骨质疏松性脊柱陈旧性骨折伴后凸畸形,可以取得良好的临床效果,但需重视术中操作及术后相邻节段椎体骨折的预防。     

单一后路病灶清除植骨内固定加局部化疗治疗胸腰椎结核

目的:探讨单一后路病灶清除植骨内固定加局部化疗治疗胸腰椎结核的临床疗效。方法:自2009年2月至2012年9月,对胸腰椎结核11例患者行单一后路病灶清除植骨内固定加局部化疗治疗,男7例,女4例;年龄27～65岁,平均53.7岁;病程3个月～2年,平均9个月。脊髓损伤程度根据ASIA损伤分级:C级3例,D级8例。根据ASIA损伤分级评估神经功能恢复程度,依据疼痛视觉评分(VAS)、Oswestry功能障碍指数(ODI)评价临床症状改善情况,通过胸腰椎侧位X线片评估后凸Cobb角的变化。结果:11例均获随访,时间12～29个月,平均18个月。脊髓损伤ASIA损伤分级:3例C级患者中2例术后提高至D级,1例提高至E级;8例D级患者中7例提高至E级,1例无变化。VAS术前为6.10±1.30,术后3 d为1.70±0.80,较术前明显改善(P<0.05).Oswestry功能障碍指数术前为(68.36±10.41)%,术后3 d为(14.55±8.99)%,较术前明显改善(P<0.05).后凸Cobb角术前为(22.64±4.84)°,术后3 d为(4.27±1.49)°,较术前明显改善(P<0.05),末次随访时为(4.55±1.70)°,与术后3 d比较Cobb角差异无统计学意义(P>0.05).随访期间无复发病例。结论:单一后路病灶清除植骨内固定加局部化疗治疗胸腰椎结核具有切口单一、手术创伤小、有效清除病灶、改善神经功能、矫正畸形、复发率低的优点,但仍需结合长期、规范的全身抗结核药物治疗。     

局麻下椎体后凸成形术治疗老年骨质疏松性椎体压缩骨折

目的: 探讨椎体后凸成形术治疗老年骨质疏松性骨折的临床疗效. 方法: 自2007年5月至2010年5月,局麻下采用椎体后凸成形术治疗老年骨质疏松性胸腰椎压缩性骨折129例,男47例,女82例;年龄61～92岁,平均73.7岁;胸椎88节,腰椎101节. 观察手术前后VAS评分的变化、椎体高度改变、局部Cobb角的改善情况. 结果: 所有患者顺利完成手术,随访时间24～60个月,平均34.2个月. 腰痛VAS评分术前为7.9±2.5,术后2周、末次随访时分别为2.8±1.8、3.0±2.2,与术前比较差异均有统计学意义(P<0.01).椎体高度术后得到部分恢复,Cobb角术前(28.3±13.7)°,术后2周、末次随访时分别为(16.2±9.8)°、(19.1±10.3)°,与术前比较差异均有统计学意义(P<0.05).术中发生骨水泥外漏23例(17.8%),其中1例出现短暂神经根压迫症状. 术后发生呼吸暂停1例,经抢救恢复;肠梗阻1例,经治疗好转;骨水泥致椎体骨折分离1例;邻椎骨折4例. 结论: 椎体后凸成形术是治疗老年骨质疏松性椎体骨折的微创外科手术,其创伤小,止痛效果好,可有效维持骨折稳定,近期、中期疗效肯定,远期有待继续随访. 手术适应证的掌握及手术技术的提高是防止并发症的关键,其中骨水泥外漏是最常见的并发症.     

脊柱侧凸数字导航模板的准确性与安全性的病例对照研究

目的:设计新型脊柱侧凸个体化数字导航模板(简称导板)并在手术中应用,评价其置钉准确性和安全性。方法:2013年12月至2014年12月,对10例脊柱侧凸病例(观察组)进行CT扫描,应用计算机软件进行模型重建、模拟置钉和导板设计;应用快速成型技术制造导板;在手术中应用导板辅助置钉,记录其出血量、手术时间、术前与术后血肌酐含量变化、置钉相关并发症发生情况,术后CT扫描明确螺钉位置并进行分级,评价置钉准确率,并与同期行徒手置钉的10例脊柱侧凸病例(对照组)进行对比。观察组包括特发性侧凸5例,先天性侧凸5例;男3例,女7例;年龄4～18岁,平均11.9岁;主弯Cobb角42.1°～78.4°,平均54.9°。对照组包括特发性侧凸5例,先天性侧凸5例,男2例,女8例;年龄6～17岁,平均12.6岁;主弯Cobb角38.2°～93.4°,平均56.6°。结果:观察组置钉167枚,其中Ⅰ级138枚(82.6%),Ⅱ级25枚(15.0%),Ⅲ级4枚(2.4%),无Ⅳ级螺钉;穿破皮质29枚(17.4%),可接受螺钉163枚(97.6%).对照组置钉165枚,其中Ⅰ级98枚(59.4%),Ⅱ级39枚(23.6%),Ⅲ级21枚(12.7%),Ⅳ级7枚(4.2%);穿破皮质67枚(40.6%),可接受螺钉137枚(83.0%).两组病例置钉分级、穿破皮质比例、可接受螺钉比例均有差异(Z=-5.013,P=0.000;χ²=9.347,P=0.002;χ²=20.242,P=0.000).Cobb角矫正率[(74.1±10.0)% vs (69.7±17.6)%,出血量(455±447) ml vs (415±389) ml,手术时间 (163.5±53.7) min vs(164.0±48.7) min,术前与术后3 d血Cr变化(-5.3±3.2) vs (-3.4±3.1) μmol/L,差异均无统计学意义(t=0.696,P=0.496;t=0.214,P=0.833;t=0.022,P=0.983;t=1.375,P=0.192).两组均未见与置钉相关的并发症。结论:应用个体化数字导航模板辅助脊柱侧凸术中椎弓根螺钉置入,准确性较徒手置钉明显提高,且安全性良好。     

脊柱调衡手法与药物治疗退变性脊柱侧凸症的病例对照研究

目的:对比脊柱调衡手法与药物治疗对退变性脊柱侧凸症患者的疼痛及功能状态的影响。方法:2010年7月至2013年6月, 将38例退变性脊柱侧凸症患者采用掷硬币的方法随机分为脊柱调衡手法组(手法组)和药物组。手法组20例, 其中男9例, 女11例, 年龄58～74岁, 平均(66.63±7.73)岁, 病程3～8个月, 平均(5.65±2.58)个月;采用脊柱调衡手法(依次循经理筋、松解痉挛、整骨扳拿、通络放松法)治疗, 时间30 min,1次/d,4 d为1疗程, 共9个疗程。药物组男8例, 女10例, 年龄57～70岁, 平均(63.51±6.61)岁, 病程3～5个月, 平均(4.82±1.43)个月;予口服塞来昔布加盐酸乙哌立松, 4 d为1疗程, 共 9个疗程。观察治疗前后两组患者的VAS评分、脊柱侧凸Cobb角及腰椎ODI评分。结果:治疗后, 手法组VAS评分5.38±0.99与药物组6.36±1.31比较差异有统计学意义(t=2.618,P<0.05);手法组Cobb角(16.51±4.89)°与药物组(19.85±5.03) °比较差异有统计学意义(t=2.074,P<0.05);手法组腰椎ODI评分20.20±2.93与药物组26.01±3.11比较差异有统计学意义(t=5.592,P<0.05).结论:采用脊柱调衡手法治疗退变性脊柱侧凸症, 能够调整脊柱两侧的肌力平衡, 矫正脊柱冠状面失衡, 恢复脊柱正常序列, 减少和消除对神经根的压迫和刺激, 缓解腰腿痛症状, 改善生活质量。     

经皮短节段内固定治疗Magerl A3伴低骨密度的胸腰椎骨折

目的:探讨经皮椎弓根钉短节段内固定加或不加中间螺钉治疗伴有低骨密度的Magerl A3胸腰椎骨折的临床疗效。方法:对2017年1月至2020年7月接受经皮椎弓根钉短节段内固定术的Magerl A3型胸腰椎骨折的患者进行回顾性分析,符合诊断和纳入标准的93例,按排除标准排除9例,余84例获得完整影像学随访资料。男38例,女46例;年龄56~73(64.78±7.12)岁;骨密度0.61~0.89(0.73±0.14) g/cm3;随访时间11~25(17.58±6.12)个月。其中加中间螺钉(A组)45例,不加中间螺钉(B组)39例。记录手术时间和术中出血量,采用Oswestry功能障碍指数(Oswestry Disability Index,ODI)和视觉模拟评分法(visual analogue scale,VAS)进行临床评估。根据术后X线片测量Cobb角,椎体楔角(vertebral wedge angle,VWA)和椎体前部高度(anterior vertebral body height,AVBH)进行影像学随访,并计算上述参数的矫正丢失度。结果:84例患者中有5例螺钉松动(A组2例,B组3例,P>0.05);两组在手术时间和术中出血量上差异有统计学意义(P<0.01);两组临床疗效良好,VAS和ODI明显改善,两组在所有随访时间(术后3 d、1 个月、末次随访)的VAS和ODI差异均无统计学意义(P>0.05);术后3 d影像学评价(Cobb角、VWA和AVBH)均较术前改善明显(P<0.05),但在术后1个月和末次随访时,两组均可观察到明显的复位丢失(P<0.05)。末次随访时,Cobb角、VWA、AVBH丢失度(差值)A组分别是(5.26±4.18)°,(4.63±3.80) °,(9.54±8.71)%;B组分别是(6.01±4.34) °,(6.55±6.21) °,(11.67±9.95)%;但两组之间的复位丢失比较差异无统计学意义(P>0.05)。结论:增加中间伤椎置钉并不能增加其稳定性,两组经皮短节段内固定均不能抵抗Magerl A3胸腰椎骨折骨折合并低骨密度的复位丢失。由于伤椎螺钉增加了手术时间及术中出血量,因此对低骨密度的老年Magerl A3胸腰椎骨折使用中间螺钉意义不大。     

后路截骨矫形对腰椎退行性后凸畸形患者脊柱骨盆矢状面参数的影响

目的：探讨后路截骨矫形对腰椎退行性后凸畸形患者脊柱-骨盆矢状面参数的影响。方法：回顾性分析2012年1月至2015年12月采用截骨手术治疗的21例腰椎退行性后凸畸形患者的临床资料,男5例,女16例;年龄55~76（66.24±5.13）岁。手术前后均拍摄脊柱全长正侧位X线片,测量脊柱骨盆矢状面参数胸椎后凸（thoracic kyphosis,TK）,腰椎前凸（lumbar lordosis,LL）,矢状面平衡（sagittal vertical axis,SVA）,骨盆入射角（pelvic incidence,PI）,骨盆倾斜角（pelvic tilt,PT）和骶骨倾斜角（sacral slope,SS）。结果：21例患者均顺利完成手术,平均手术时间190 min（160~220 min）,术中平均出血量1 000 ml（800~1 900 ml）。术前与术后1年各项参数分别为,TK由（31.67±21.13）°增加到（34.67±11.60）°,LL从（4.76±3.17）°矫正至（37.41±6.28）°,PT从（33.94±5.01）°恢复至（20.12±5.36）°,SS从（18.47±2.60）°增至（31.71±4.30）°,SVA从（13.24±3.60）cm恢复至（2.82±1.33）cm,所有参数手术前后比较差异有统计学意义（P<0.05）。结论：后路截骨矫形手术能够有效地重建腰椎退行性后凸畸形患者脊柱-骨盆矢状面平衡,腰椎前凸及骶骨倾斜角的恢复与重建矢状面平衡密切相关。     

高海拔地区应用伤椎置钉技术治疗脊柱爆裂骨折

目的:针对高海拔地区脊柱爆裂骨折的特点及当地医疗条件,探讨椎弓根螺钉短节段固定联合伤椎置钉技术治疗胸腰椎爆裂骨折的临床疗效。方法:自2018年8月至2021年12月,采用伤椎置钉技术治疗12例无神经症状的单椎体胸腰椎爆裂骨折患者,其中男7例,女5例;年龄29~54(42.50±7.95)岁;车祸伤6例,高坠伤4例,重物砸伤2例;T₁₁2例,T₁₂4例,L₁3例,L₂2例,L₃1例。手术首先在骨折上下椎置钉,并在伤椎置入椎弓根螺钉,安装连接棒,通过体位及撑开实现骨折椎体复位。应用视觉模拟评分(visual analogue scale,VAS)及日本骨科协会(Japanese Orthopaedic Association,JOA)评分评估患者疼痛及生活质量改变情况,通过X线测量受伤节段后凸矫正率及矫正丢失率。结果:所有患者手术顺利,术中无明显并发症,12例患者均获随访,时间9~27(17.75±5.79)个月。术后3 d,VAS与术前入院时相比差异有统计学意义(t=6.701,P=0.000);术后9个月JOA评分与术前入院时相比差异有统计学意义(t=5.085,P=0.000)。术后3 d,Cobb角为(4.42±1.16) °,与术前入院时的(25.67±5.71) °相比矫正率为(82±5)%;术后9个月Cobb角(5.08±1.24) °,矫正丢失率为(16±13)%。无内固定松动及断裂。结论:高原低气压低氧环境下,应保证手术效果的同时减少创伤,应用伤椎置钉技术能够有效恢复并维持伤椎高度,出血少,固定节段短,是治疗高海拔地区脊柱爆裂骨折的有效方法。     

斜外侧腰椎椎间融合术联合后路导航长节段内固定治疗退行性脊柱侧凸

目的：观察斜外侧腰椎椎间融合术（oblique lumbar interbody fusion,OLIF）联合后路O形臂CT导航长节段内固定治疗退行性脊柱侧凸的早期临床疗效。方法：对2016年4月至2017年12月接受OLIF联合后路O形臂CT导航长节段内固定手术治疗的15例退行性脊柱侧凸患者进行回顾性分析,其中男3例,女12例;年龄55~73（62.2±5.3）岁。记录患者手术时间、术中出血量、术中椎弓根螺钉优良率及并发症情况;于术前、术后1周及末次随访时采用疼痛视觉模拟评分（visual analogue scale,VAS）和Oswestry功能障碍指数（Oswestry Disability Index,ODI）分别对患者的临床症状进行评估;同期行脊柱全长站立位X线片,术后6个月行腰椎CT检查,观察冠状位侧凸Cobb角,腰椎前凸角（lumbar lordosis,LL）,椎间隙高度,矢状面平衡（sagittal vertical axis,SVA）,椎间融合等情况。结果：患者OLIF手术时间（98.7±16.8）min,术中出血量（50.2±10.7）ml。后路O形臂CT导航长节段内固定手术时间（101.5±23.4）min,术中出血量（63.1±19.7）ml。总手术时间（200.2±40.2）min,术中出血量（113.3±30.4）ml。术后15例患者均获随访,时间12~25（16.5±5.3）个月。腰痛VAS评分、下肢痛VAS评分及ODI分别由术前的（6.8±1.6）分、（6.2±1.1）分和（64.6±10.4）%降低至末次随访时的（1.4±1.0）分、（1.0±0.5）分和（15.8±4.5）%,差异均有统计学意义（P<0.05）。冠状位侧凸Cobb角和SVA分别由术前的（20.3±13.5）°、（42.3±16.5）mm降低至末次随访时的（5.5±3.1）°、（25.1±10.9）mm,差异均有统计学意义（P<0.05）。LL和椎间隙高度由术前的（25.8±8.2）°、（5.9±2.7）mm提升至末次随访时的（39.3±9.1）°、（10.9±1.2）mm,差异均有统计学意义（P<0.05）。O形臂CT导航置钉240枚,术中O形臂三维扫描优良率为96%（230/240）。术后6个月腰椎CT显示椎间融合器均骨性融合。1例患者术后出现左大腿前内侧疼痛,2例患者术后出现短暂的左侧屈髋无力,均在随后的随访中恢复。结论：斜外侧腰椎椎间融合术联合后路O形臂CT导航长节段内固定治疗退行性脊柱侧凸的早期临床疗效满意,具有微创、导航置钉准确、骨融合率高及并发症少等优点,可为退行性脊柱侧凸的微创治疗提供新的选择。     

后路短节段固定结合潜行减压治疗上腰椎爆裂性骨折

目的:观察后路短节段固定结合保留后方韧带复合体(PLC) 的潜行减压治疗上腰椎爆裂性骨折的临床效果。方法:2010年10月至2013年3月采用后路短节段复位固定和保留PLC的潜行减压治疗上腰椎爆裂性骨折患者(Denis B型)23例,男18例,女5例;年龄26～64岁,平均45.7岁;高处坠落伤12例,车祸伤5例,重物砸伤4例,其他外伤2例;L1骨折14例,L2骨折9例;伴神经损害13例(ASIA评分D级).术后12～20个月(平均14.3个月)取出内固定。术后定期随访并比较各时间点神经功能JOA评分和影像学动态变化。结果:所有患者获得随访,时间18～24个月,平均20.4个月。13例伴神经损害者术后3～6个月神经症状均完全恢复。术后1年和去除内固定后3个月JOA评分分别为20.63±0.92和20.38±1.06,较术后3个月的9.90±2.73明显改善(P<0.05).术后1年伤椎前缘高度、伤椎楔变角、局部Cobb角分别为(95.1±0.53)%、(2.78±1.36)°、(2.43±1.52)°,均较术前明显改善(P<0.05).去除内固定3个月后与术后1年JOA评分及影像学结果比较差异无统计学意义(P>0.05) .结论:后路短节段复位固定结合保留PLC的潜行减压治疗上腰椎爆裂性骨折创伤小,能有效恢复椎体高度,维持脊柱稳定性,减轻术后腰背痛,是安全有效的手术方式。     

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.     

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.     

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.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.