退变性腰椎侧凸患者椎旁肌退变与术后近端交界性后凸的相关性研究

目的:探讨退变性腰椎侧凸(degenerative lumbar scoliosis,DLS)患者术前腰椎椎旁肌肉的退变程度与后路长节段固定融合术后近端交界性后凸(proximal junctional kyphosis,PJK)发生的关系。方法:本研究共纳入52例DLS患者,根据末次随访是否发生PJK分为PJK组(10例)及无PJK(non-PJK)组(42例)。影像学评估包括脊柱骨盆矢状位参数、腰椎椎旁肌肌量(肌肉与椎体/椎间盘横截面积比值)以及肌肉-脂肪指数(肌肉与皮下脂肪的平均信号强度之比)。利用Logistic回归分析PJK发生的危险因素。比较两组患者一般资料、术前及随访时腰痛VAS及健康相关生活质量评分(SRS-22)。结果:本组患者PJK发生率为19.23%。患者手术年龄、性别、身体质量指数、患病时长、糖尿病、截骨及椎间融合、固定节段数、减压节段数、骨密度T值在PJK组及无PJK组均未见明显统计学差异。术前骨矿盐密度(bone mineral density,BMD)较低、术前胸腰段后凸角(TLK)较大、术中胸椎后凸角(TK)矫正过大、最上端固定椎(UIV)位于T12-L1、术后即刻交界性后凸角(PJA)过大、术前骶骨倾斜角(SS)较小、术后PJA变化值较大、腰背伸肌群脂肪退变明显可能与腰椎退变性侧凸长节段固定术后发生PJK相关。通过Logistic回归分析发现,术前SS25°(OR=12.902,P=0.046)、术后即刻PJA增大≥3.6°(OR=21.940,P=0.015)、腰背伸肌肌肉-脂肪指数≥27.65(OR=11.749,P=0.019)为发生PJK的独立危险因素。PJK患者的随访腰痛VAS及SRS-22功能状态评分较non-PJK组差。结论:DLS术后发生PJK患者,术前腰椎椎旁肌肌量较低、脂肪退变明显。术前SS25°、术后即刻PJA增大≥3.6°、腰背伸肌肌肉-脂肪指数≥27.65为发生PJK的独立危险因素。     

脊柱侧后凸/后凸畸形SRS-Schwab四级截骨术后近端交界性后凸的危险因素分析

目的:探讨脊柱侧后凸/后凸畸形患者SRS-Schwab四级截骨术后发生近端交界性后凸(proximal junctional kyphosis,PJK)的相关危险因素。方法:回顾性分析2011年5月～2015年12月于我院行SRS-Schwab四级截骨手术且具有完整临床及影像学资料的46例脊柱侧后凸/后凸畸形患者,其中男性24例,女性22例,手术时年龄23.1±19.7岁。记录患者体重指数、融合节段、最上端固定椎(upper instrumented vertebra,UIV)位置及置钉密度等。测量术前、术后3个月及末次随访时的胸椎后凸角(thoracic kyphosis,TK)、腰椎前凸角(lumbar lordosis,LL)、骨盆入射角(pelvic incidence,PI)、局部后凸角(segmental kyphosis,SK)、主弯Cobb角(main curve,MC)、矢状面平衡(sagittal vertical axis,SVA)及近端交界角(proximal junctional angle,PJA)。根据患者术后是否发生PJK分为非PJK组和PJK组,采用t检验、χ2检验或Fisher精确检验对比两组临床资料及影像学参数,利用多因素Logistic回归分析确定PJK发生的危险因素。结果:46例患者术后随访24～63个月(36.9±13.4个月),其中11例(23.9%)发生PJK,以Ⅰ型PJK(8/11)最为常见,8例发生于术后6个月内。PJK组和非PJK组患者性别、年龄、随访时间、体重指数、融合节段、骨密度、置钉密度、UIV位置均无统计学差异(P0.05)。PJK组患者术前TK40°(6/11)和SK矫正30°(7/11)的比例均高于非PJK组(P0.05)。两组患者间术前PJA、LL、MC、PI、SVA和术后及末次随访时TK、LL、MC、SK、PI、SVA改变均无统计学差异(P0.05)。回归分析结果显示术后SK矫正30°(OR=7.000,95%CI=1.591-30.800,P=0.010)是PJK发生的独立危险因素。PJK组术前PJA为7.5°±3.0°,术后3个月为20.8°±4.1°,末次随访时为22.0°±4.5°,交界性后凸未见明显加重。结论:脊柱侧后凸/后凸畸形患者SRS-Schwab四级截骨术后PJK发生率为23.9%,其主要发生于术后6个月内,脊柱后凸畸形过度矫正是其独立危险因素。     

Ⅰ型神经纤维瘤病合并脊柱侧凸术后近端交界性后凸的临床分析

[目的]探讨Ⅰ型神经纤维瘤病(neurofibromatosis type 1, NF1)合并营养不良性脊柱侧凸术后发生近端交界性后凸(PJK)的发生率和危险因素。[方法]回顾性分析2007年1月～2015年6月期间接受后路矫形手术、有完整临床及影像学资料的103例NF1合并营养不良性脊柱侧凸患者的临床资料,男49例,女54例。术前、术后3个月及末次随访时测量脊柱骨盆参数、局部后凸角(SK)、主弯Cobb角及近端交界角(PJA),记录PJK发生情况并分析其危险因素。[结果]术后平均随访(34.97±14.47)个月,22例发生了PJK,其中16例于术后6个月内发生,最常见的类型为Ⅰ型(63.64%)和Ⅱ型(27.27%)。PJK组术前PJA为7.42°,术后6个月为21.83°,末次随访时为23.82°。12例患儿接受支具治疗,1例行翻修手术。PJK组患者术前TK60°、SK矫正40°、UIV位于T3～5和T8～9的发生率均高于非PJK组(P0.05),而两组患者术前PJA、LL、UIV固定方式及融合节段等差异均无统计学意义(P0.05)。回归分析结果显示TK60°(OR=3.758,P=0.032)、 UIV位于T_(3～5)或T_(8～9)(OR=5.837,P=0.030)是PJK发生的独立危险因素。[结论] NF1合并营养不良性脊柱侧凸术后PJK主要发生于术后6个月内;术前后凸畸形、UIV位于T_(3～5)和T_(8～9)是其发生的危险因素。     

后路长节段固定融合术治疗腰椎退行性疾病术后近端交界性后凸的相关因素分析

目的对后路长节段固定融合术治疗腰椎退行性疾病(lumbar degenerative diseases,LDD)术后近端交界性后凸(proximal junctional kyphosis,PJK)的相关因素进行分析,为其预防提供理论依据。方法纳入后路长节段固定融合术治疗的105例腰椎退行性疾病患者,随访18个月,将PJK患者设为观察组,非PJK患者设为对照组,调查两组患者一般资料以及影像学资料,采用单因素与多因素Logistic回归分析确定术后PJK的独立危险因素。结果 105例患者术后发生PJK 20例,发生率19.05%。两组上端固定椎(upper instrumented vertebra,UIV)位于胸腰段、身体质量指数(Body Mass Index,BMI)、近端交界性后凸角(proximal junctional kyphosis angle,PJKA)、合并骨质疏松、骶骨倾斜角(sacral slope,SS)差异有统计学意义(P0.05); Logistic回归分析结果显示:PJKA10°(OR=2.435)、UIV位于胸腰段(OR=1.764)、合并骨质疏松(OR=2.215)、SS25°(OR=1.976),均是术后发生PJK的独立危险因素。结论 PJK发生率较高,UIV位于胸腰段、PJKA10°、合并骨质疏松、SS25°,均会增加后路长节段固定融合术治疗LDD术后PJK发生的风险。     

强直性脊柱炎胸腰椎后凸畸形截骨矫形术后近端交界性后凸的危险因素与临床意义

目的 :探讨强直性脊柱炎(ankylosing spondylitis,AS)胸腰椎后凸畸形矫形术后发生近端交界性后凸(proximal junctional kyphosis,PJK)的危险因素及表现形式。方法 :回顾性分析2002年1月~2015年12月接受矫形手术且随访大于2年的133例AS胸腰椎后凸畸形患者,男性118例,女性15例,年龄35.1±9.8岁(18~63岁)。收集患者临床资料,包括年龄、性别、体重指数、截骨方式和椎体融合节段。术前、术后及每次随访拍摄全脊柱正侧位片,并测量矢状面平衡(sagittal vertical axis,SVA)、胸椎后凸角(thoracic kyphosis,TK)、腰椎前凸角(lumbar lordosis,LL)、骶骨倾斜角(sacral slope,SS)、骨盆倾斜度(pelvic tilt,PT)、骨盆投射角(pelvic incidence,PI)和近端交界角(proximal junctional angle,PJA)。根据PJA将患者分为PJK组和非PJK组,利用卡方检验及t检验对比两组间临床资料及影像学参数。结果:133例患者平均随访3.6±2.2年(2.0~15.0年),11例发生PJK,平均在术后随访3.7年(0.3~15.0年)发生,PJA从术前5.5°±9.7°进展至21.2°±9.5°。PJK组手术年龄低于非PJK组(P0.01),PJK组行SPO人数比例高于非PJK组(P0.01)。PJK组术前PJA和SVA均低于非PJK组(P0.05)。两组间TK、LL、SS、PT和PI均无显著性差异(P0.05)。11例PJK患者中,有3种PJK表现形式,包括假关节(2例)、压缩性骨折(3例)和AS胸椎后凸畸形的自然进展(6例)。末次随访时,1例假关节PJK患者自发性愈合,1例AS胸椎后凸畸形自然进展的PJK患者行翻修手术,其余患者均予以随访观察。结论:AS术后PJK表现形式包括假关节、压缩性骨折和AS胸椎后凸畸形的自然进展。初次手术年龄、手术方式、术前PJA及SVA影响PJK的发生。     

腰椎退行性疾病后路手术术后近端交界性后凸危险因素分析

目的探讨腰椎退行性疾病(lumbar degenerative diseases,LDD)行后路固定融合术后近端交界性后凸(proximal junctional kyphosis,PJK)的发生情况及危险因素。方法纳入2014年1月～2017年1月采用后路固定融合治疗的167例LDD患者,术后随访18～38个月,观察术后PJK发生情况,分别设为PJK组与非PJK组。调查两组患者性别、年龄以及手术前影像学资料等,组间各项目通过单因素分析与多因素分析确定LDD后路固定融合术后PJK的独立危险因素。结果术后发生PJK 25例,发生率14.97%; PJK组与非PJK组身体质量指数(Body Mass Index,BMI)、合并骨质疏松、术前PJK角度(PJKA)、年龄、腰椎前凸角(LL)、骶骨倾斜角(SS)、融合节段数差异有统计学意义(P0.05);多因素logistic回归分析结果显示,BMI25 kg/m2(OR=3.778)、合并骨质疏松(OR=2.985)、PJKA10°(OR=3.567)、年龄70岁(OR=2.877)是术后发生PJK的独立危险因素。结论 LDD后路固定融合术后易发生PJK,BMI25 kg/m2、合并骨质疏松、PJKA10°、年龄70岁均会增加其发生风险。     

成人退行性脊柱侧凸后路长节段腰椎体间融合术后发生近端交界性后凸的危险因素

目的 :分析成人退行性脊柱侧凸(ADS)经长节段后路腰椎体间融合术(PLIF)后近端交界性后凸(PJK的发生率和相关危险因素。方法:回顾性分析2013年6月～2016年1月在我院行长节段PLIF治疗的144例ADS患者,术后43例发生PJK(PJK组),无PJK组101例。收集两组患者基本资料和临床功能评分,包括年龄、性别、随访时间、体重指数(BMI),术前合并贫血、糖尿病、高血压病和心脏病情况,吸烟情况,既往手术史,住院时间,术前与末次随访时的Oswestry功能障碍指数(Oswestry disability index,ODI)、JOA评分、VAS评分和末次随访时的腰椎僵硬性残疾指数(lumbar stiffness disability index,LSDI)评分;与手术相关的参数,包括术中出血量、手术用时、融合节段、减压节段、骶骨融合、后方韧带复合体(PLC)损伤、截骨术、螺钉松动、断棒、脑脊液漏、假关节形成、再手术、术前与末次随访Cobb角、术前骨盆入射角(PI)-腰椎前凸角(LL)、末次随访时的PILL、术前与末次随访时的矢状面垂直轴(SVA)。对比两组术后即刻影像学参数,包括骨盆倾斜角(PT)、PI、骶骨倾斜角(SS)、LL、PI-LL、胸椎后凸角(TK)、LL-TK、实际腰椎前凸角(RLL)、实际胸椎后凸角(RTK)、实际腰椎前凸角与实际胸椎后凸角匹配值(RLL-RTK)、上端椎坡度(UIVs)、上端椎倾斜角(UIVi)、SVA、UIV与C7垂线距离(UIVa)与UIV上终板前缘与椎体后缘垂线距离(UIVb)的比值(UIVa/b)。组间连续变量比较采用One-Way ANOVA检验,然后再用SNK法进行多重检验;分类变量采用χ~2检验,而非连续数据的统计学显著性通过Pearson卡方检验进行比较。以可疑危险因素为自变量,以是否出现PJK作为因变量对其进行单因素分析,然后将有统计学意义的自变量代入Logistics模型进行多因素回归分析,最终确定PJK相关危险因素。Pearson相关检验(r)用于评估骨盆与脊柱参数的相关性。结果:患者一般资料中,性别、BMI、糖尿病、吸烟、末次随访ODI和LSDI评分两组间差异有统计学意义(P0.05)。在手术相关参数中,术中出血量、融合节段数、减压节段数、骶骨融合、PLC损伤、再手术率、术前PI-LL、末次随访PI-LL和末次随访SVA两组比较有统计学差异(P0.05)。术后即刻影像学参数中,PT、SS、LL、PI-LL、LL-TK、RLL、RLL-RTK、UIVs、UIVi和UIVa/b两组比较有统计学差异(P0.05)。将组间比较结果有统计学差异的参数进行单因素分析后有意义的参数包括性别、BMI、糖尿病、吸烟、LL-TK、UIVs、UIVa/b、PI-LL、骶骨融合和PLC损伤。再经多因素Logistics回归分析,结果显示ADS术后发生PJK的独立危险因素包括BMI(OR 1.6,P=0.000)、吸烟(OR 3.1,P=0.016)、UIVs(OR 2.0,P=0.015)和PI-LL(OR 1.2,P=0.015)。在脊柱骨盆参数Pearson相关系数分析中发现,SVA与UIVa/b、UIVs和UIVi之间存在较高的相关性(r=-0.93,P0.001)、(r=-0.66,P0.001)和(r=-0.68,P0.001);UIVa/b与UIVs及UIVi之间存在较高的相关性(r=-0.63,P0.001)和(r=0.-68,P0.001)。结论:接受长节段PLIF的ADS患者术后发生PJK的独立危险因素为BMI、吸烟、UIVs和PI-LL。UIVa/b可以反映SVA情况和UIV倾斜情况,可作为发生PJK的预测因子。     

腰椎退行性疾病术后近端交界性后凸的危险因素及治疗

背景:老年腰椎退行性疾病的手术治疗中,有时需要进行长节段固定融合,在获得稳定的同时,可能带来固定节段近端交界性后凸(PJK)。目的:回顾腰椎长节段固定融合病例,对PJK发生的危险因素、发生后的处理、预防方法等进行分析。方法:选取2013年1月至2018年6月行腰椎长节段固定融合术后患者117例,最终82例获得随访(随访率70%),记录患者年龄、性别、身高、体重、随访时间、骨密度、体重指数、固定节段等。手术前后及随访时行X线检查,使用Surgimap软件测量胸椎后凸角(TK)、腰椎前凸角(LL)、脊柱矢状轴(SVA)、近端交界角(PJA)、脊柱整体力线(GSA)、骨盆入射角(PI)、骨盆倾斜角(PT)、骶骨倾斜角(SS),记录Oswestry功能障碍指数(ODI)。对发生PJK的患者记录Hart-ISSG PJKSS量表得分。结果:远端固定到S1的患者以及近端固定到胸腰段的患者PJK发生比例更高。PJK组术前LL、SS较非PJK组更小,术前SVA、PI-LL、GSA较非PJK组更大。末次随访时,27例患者发生PJK(32.9%,27/82),其中9例患者行翻修手术。结论:长节段固定融合手术时远端固定椎应尽量选择L5及L5近端,而近端固定椎尽可能避开胸腰段。对于术前矢状位失衡明显的患者应重视矢状位平衡的恢复,Hart-ISSG PJKSS量表对PJK患者翻修手术具有一定指导价值。     

退变性腰椎侧凸长节段融合术后远端交界性问题分析

目的 :探讨退变性腰椎侧凸(degenerative lumbar scoliosis,DLS)长节段固定融合术后远端交界性问题(distal junctional problem,DJP)的发生率、危险因素及对患者生活质量的影响。方法 :2009年4月～2017年10月在我院确诊为DLS、年龄≥40岁、行长节段(≥4个节段)固定融合手术、随访时间≥1年的患者132例,将随访时出现DJP的13例患者纳入DJP组,未出现任何机械性并发症的41例患者纳入对照组。对个体因素[手术时的年龄、性别、体重指数(body mass index,BMI)、骨密度(bone mineral density,BMD)和T值、合并糖尿病和高血压情况、美国麻醉医师学会(ASA)分级等因素]、手术因素[固定融合节段数、远端固定椎(lowest instumented vertebra,LIV)位置、截骨操作和椎间融合情况]以及术前和术后影像学参数[侧凸Cobb角、顶椎的旋转程度(Nash-Moe)、顶椎偏移距离(apical vertebral translation,AVT)、冠状位平衡(coronal vertical axis,CVA)、胸椎后凸角(thoracic kyphosis,TK)、胸腰段后凸角(thoracolumbar kyphosis,TLK)、腰椎前凸角(lumbar lordosis,LL)、骨盆入射角(pelvic incidence,PI)、骨盆倾斜角(pelvic tilt,PT)、骶骨倾斜角(sacral slope,SS)、矢状位平衡(sagittal vertical axis,SVA)、T1骨盆角(T1 pelvic angle,TPA)、躯干整体倾斜角(global tilt,GT)等]进行单变量和多变量分析。比较两组术前和随访时的腰痛视觉模拟(visual analog scale,VAS)评分、下肢痛VAS评分、Oswestry功能障碍指数(Oswestry disability index,ODI)、日本骨科学会(Japanese Orthopaedic Association,JOA)-29评分、脊柱研究学会(Scoliosis Research Society-22,SRS-22)评分和健康状况调查简表(short form 36 health survey questionnaire,SF-36)评分。结果 :本组患者DJP的发生率为9.8%(13/132),其中6例(46.2%)患者进行了翻修手术。DJP组患者骨密度T值显著低于对照组,DJP患者骨量减少及骨质疏松的比例显著高于对照组(P0.05),其他个体因素无显著性差异。两组手术因素均无显著性差异。与对照组相比,DJP组患者术前TLK较大、PT较小、SVA70mm的比例较高(53.85%vs 19.51%,P=0.040);术后即刻TLK、SVA显著大于对照组,矢状位失衡患者比例显著高于对照组(46.15%vs 14.63%,P=0.046),其他影像学参数无显著性差异。Logistic回归分析提示骨质疏松(OR=8.90,95%CI=1.95～40.51,P=0.005)、术后即刻矢状位失衡(OR=5.82,95%CI=1.15～29.42,P=0.033)发生DJP的风险分别增加了7.9倍、4.8倍。两组患者术前各项健康相关生活质量评分均无统计学差异;对照组患者术后各项健康相关生活质量评分较术前均有显著性提高(P0.05),而DJP组患者ODI、JOA评分、SF-36精神健康较术前无明显提高(P0.05);与对照组比较,DJP组随访时腰痛VAS评分、ODI、JOA评分、SRS疼痛、SRS功能状况、SRS亚总分、SRS治疗满意度、SF-36生理健康评分、SF-36精神健康评分更差。结论:DLS长节段固定融合术后9.8%的患者发生了远端交界性问题,严重影响患者术后生活质量改善;骨质疏松和术后即刻矢状位失衡是发生DJP的独立危险因素。     

术前脊柱后方肌群肌力对长节段固定融合纠正退行性脊柱侧凸矢状位失衡的影响

目的:评估退行性脊柱侧凸畸形患者术前脊柱后方肌群肌力对长节段固定融合纠正矢状位失衡效果的影响。方法:回顾性研究2014年1月~2015年10月于我院接受长节段固定融合手术的退行性脊柱侧凸畸形患者32例。于术前对所有患者进行腰背肌力量测试,将可完成"小燕飞"动作的12例患者分为A组,年龄55~73岁(65.2±4.7岁);将无法完成"小燕飞"动作的20例患者分为B组,年龄55~75岁(64.8±4.9岁)。随访1.3~2年(1.5±0.5年)。比较两组术前、术后即刻及末次随访时矢状位影像学参数[腰椎前凸角(lumbar lordosis,LL)、胸椎后凸角(thoracic kyphosis,TK)、胸腰段后凸角(thoracic lumbar kyphosis,TLK)、骨盆倾斜角(pelvic tilt,PT)、骶骨倾斜角(sacral slope,SS)、矢状位垂直偏距(sagittal vertical axis,SVA)、近端交界区后凸角(proximal junctional angle,PJA)等]以及临床功能评分[Oswestry功能障碍指数(ODI)、JOA评分和腰背痛VAS评分]。结果:两组患者的年龄、手术时长、术中出血量及平均住院日均无统计学差异,具有可比性。术前A组的LL、TLK、TK、SVA、PT、PI、SS、ODI、腰背痛VAS评分、JOA评分为29.6°±3.2°、33.5°±4.6°、54.6°±5.1°、9.9±2.1cm、28°±2.4°、54.8°±4.1°、26°±3.7°、(75.4±3.5)%、7.3±0.9分、8.7±0.5分;B组为29.7°±3.6°、35.3°±3.8°、55.2°±3.7°、9.4±1.6cm、28°±1.6°、52.2°±1.7°、23.4°±2.9°、(76.4±2.2)%、7.2±0.7分、8.5±0.5分。术后即刻A组的LL、TLK、TK、SVA、PJA、PT、SS、ODI、腰背痛VAS评分、JOA评分为41.5°±4.1°、8.8°±3.6°、25.8°±2.1°、3.6±1.0cm、3.6°±1.1°、14.8°±1.2°、40.8°±2.5°、(21.9±2.3)%、2.4±0.7分、23.2±1.4分;B组为40.6°±2.2°、10.1°±3.2°、27.3°±1.9°、3.5±1.0cm、3.8°±1.1°、16.9°±2.3°、35.3°±2.7°、(20.3±2.2)%、2.9±0.6分、23.0±1.3分;末次随访时A组为43.6°±4.3°、10.8°±3.6°、28.7°±1.8°、4.8±1.0cm、4.4°±1.5°、15.8°±1.2°、41.8°±2.7°、(14.5±5.1)%、2.0±1.6分、24.7±0.7分;B组为43.2°±2.0°、18.6°±3.2°、38.4°±3.2°、8.7±1.6cm、8.3°±2.6°、23.6°±2.6°、9.1°±3.3°、(28.7±3.2)%、4.6±1.7分、24.0±1.0分。两组术前和术后即刻的矢状位参数以及功能评分无统计学差异(P0.05);末次随访时两组LL无显著性差异(P0.05),TK、TLK、PT、SS、SVA、PJA均有统计学差异(P0.05),B组3例出现近端交界性后凸(proximal junctional kyphosis,PJK)。末次随访时两组ODI、腿痛VAS评分有统计学差异(P0.05),A组优于B组;JOA评分无统计学差异(P0.05)。结论:术前脊柱后方肌群肌力对退行性脊柱侧凸畸形长节段固定术后矢状位纠正起到重要作用,术前良好的腰背肌力量可减少长节段固定术后矢状位纠正的丢失,从而降低交界性后凸等并发症的发生率。     

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.     

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.     

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.     

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.