不同方式下骨水泥强化椎弓根螺钉固定手术治疗伴骨质疏松症腰椎退变性疾病的疗效对比

目的观察不同方式下骨水泥强化椎弓根螺钉固定手术治疗伴骨质疏松症腰椎退变性疾病的临床疗效。方法回顾性分析60例伴骨质疏松症腰椎退变性疾病患者的临床资料,根据固定方式分为观察组和对照组,每组30例,观察组采用新型可灌注椎弓根螺钉+PMMA骨水泥固定,对照组采用常规椎弓根螺钉+PMMA骨水泥固定。结果观察组手术时间显著短于对照组(P0.05),两组患者末次随访Cobb角度、椎间隙高度、椎体变形指数、上椎板凹陷角度、下椎板凹陷角度较术前显著改善(P0.05),且与对照组比较,观察组椎间隙高度、椎体变形指数等显著降低(P0.05)。两组患者末次随访VAS评分、JOA评分和ODI评分较术前显著改善(P0.05),且组间比较无显著性差异(P0.05)。两组患者并发症发生率,差异不具有统计学意义(P0.05)。结论新型可灌注椎弓根螺钉骨水泥强化固定治疗伴骨质疏松症腰椎退变性疾病疗效显著,且能够降低骨水泥渗漏及螺钉松动和断裂的风险。     

彩色多普勒超声在置入外侧“in-out-in”枢椎椎弓根螺钉术中对椎动脉观察的价值

【摘要】 目的：探讨在寰枢椎脱位或不稳的枕颈后路手术中置入外侧“in-out-in”枢椎椎弓根螺钉前后,利用彩色多普勒超声对椎动脉观察并辅助螺钉置入的临床价值。方法：回顾性分析2016年1月~2022年1月,在枕颈后路手术中置入外侧“in-out-in”枢椎椎弓根螺钉内固定治疗的47例寰枢椎脱位或不稳的患者资料。其中,男30例,女17例,年龄21~68岁（42.2±18.9岁）;单侧枢椎椎弓根狭窄40例,双侧狭窄7例。观察组23例在显露完成后、钉道制备后、置入螺钉后3个时间点采用彩色多普勒超声观察椎动脉的形态并测量其直径,根据直径变化,决定最终置入螺钉长度;对照组24例基于钉道出血情况依据经验判断置入外侧“in-out-in”枢椎椎弓根螺钉。记录围手术期并发症,比较两组手术时间、术中出血量。患者均获得6~24个月（平均11个月）随访,术前及术后5d行X线、CTA和MRI检查,观察内固定及椎动脉情况;术后3、6、12个月行X线和CT检查,观察植骨融合情况;比较术前、术后5d及末次随访时的日本骨科协会（Japanese Orthopaedic Association,JOA）评分,评估患者的临床疗效。结果：两组患者手术顺利。观察组1例钉道制备后出现一侧椎动脉直径较显露完成时明显减小,使用短螺钉固定,余椎动脉直径在3个时间点分别为3.15±0.61mm、3.09±0.72mm、3.21±0.57mm,差异无统计学意义（P>0.05）。观察组、对照组手术时间分别为199.1±52.4（138~257）min、182.2±41.5（129~231）min;出血量分别为401.2±185.3（210~650）mL、415.3±201.7（230~660）mL,差异均无统计学意义（P>0.05）。术后CTA发现对照组1例出现一侧椎动脉被椎弓根螺钉压闭,无临床症状,无脊髓损伤等并发症。术后6个月CT检查示植骨融合,无内固定松动、移位。术后5d及末次随访时观察组JOA评分分别为13.1±2.1分、14.2±1.9分,与术前（7.8±1.9分）比较明显改善（P＜0.05）;对照组术后JOA评分分别为12.9±1.7分、13.8±2.2分,与术前（8.1±2.5分）比较明显改善（P＜0.05）;两组间比较JOA评分在各时间点差异均无统计学意义（P>0.05）。结论：在枕颈后路手术中置入外侧“in-out-in”枢椎椎弓根螺钉时利用彩色多普勒超声对椎动脉观察,可观察到椎动脉形态及直径,不增加手术时间和创伤。     

PVP治疗中上段胸椎骨质疏松性重度椎体压缩骨折的临床效果

【摘要】 目的：探讨经皮椎体成形术（percutaneous vertebroplasty,PVP）治疗中上段胸椎（T6以上胸椎）骨质疏松性重度椎体压缩骨折（severe vertebral compression fractures,SVCF）的临床效果。方法：回顾性分析2011年1月~2012年12月我院采用PVP治疗的12例中上段胸椎骨质疏松性SVCF患者,男4例,女8例;年龄61~83岁,平均74.5岁。骨折节段：T2 1例,T3 3例,T5 3例,T6 5例。受累节段椎体前缘平均压缩为68%（65%~72%）。腰椎骨密度T值为-3.8~-5.2,平均-4.2。术前胸背痛VAS评分为6.75±1.14分,ODI为（68.58±5.70）%,受累节段椎体前缘高度为0.96±0.09cm,受累节段椎体后凸角为18.90°±1.03°。均行PVP,其中10例采用椎弓根入路,2例采用椎弓根外侧入路,所有患者均采取双侧穿刺置管。结果：所有患者均顺利完成手术,10例经椎弓根入路的手术时间为27～51min,平均41min;2例经椎弓根外侧入路的平均手术时间为62min。术中出血量为5～16ml,平均10ml。骨水泥注入量为1.7~2.8ml,平均为2.2ml。1例术前CT显示上终板裂口的患者术后发现椎间隙骨水泥渗漏,但无不适症状,未行特殊处理。术后2d,胸背痛VAS评分为3.17±1.03分,ODI为（33.00±17.54）%,均较术前明显改善（P＜0.05）;受累节段椎体前缘高度为0.98±0.11cm,受累节段椎体后凸角为19.10°±0.99°,与术前比较无明显改善（P＞0.05）。随访6个月～1年,手术椎体未再发生骨折及塌陷,未发现相邻节段骨折。末次随访时,胸背痛VAS评分为3.75±0.85分,ODI为（32.33±17.11）%,受累节段椎体前缘高度为0.97±0.12cm,受累节段椎体后凸角为19.08°±1.00°,与术后2d比较均无统计学差异（P＞0.05）。结论：PVP治疗中上段胸椎骨质疏松性SVCF可以有效缓解胸背痛,但受累节段椎体前缘高度及后凸角恢复不显著。     

椎弓根螺钉短节段固定联合椎体成形术治疗单节段胸腰段骨质疏松性椎体爆裂骨折

【摘要】 目的：探讨椎弓根螺钉短节段固定联合椎体成形术治疗单节段胸腰段骨质疏松性椎体爆裂骨折的临床疗效。方法：回顾性分析我院2008年1月～2012年3月收治的86例单节段胸腰段爆裂椎体骨折患者的临床资料,对其中32例合并骨质疏松症的患者进行随访分析。男14例,女18例;年龄56～78岁,平均64.5岁;跌倒伤14例,车祸伤9例,高处坠落伤5例,重物砸伤4例;骨折节段：T11 3例;T12 10例;L1 15例;L2 4例。手术时均在骨折上下椎置入椎弓根螺钉,安装连接棒,通过体位结合撑开实现骨折椎体复位,然后在伤椎注入骨水泥。应用VAS及SF-36量表评估患者疼痛及生活质量改变情况,通过X线片测量计算伤椎椎体前缘高度恢复、受伤节段后凸矫正及丢失情况,随访观察治疗效果。结果：所有患者均顺利完成手术,术中无明显并发症。随访12～36个月,平均16.5个月。术后VAS评分（2.43±1.81分）及末次随访时VAS评分（2.17±1.81分）与术前（7.67±2.25分）比较差异有统计学意义（P<0.05）;末次随访SF-36评分（123.5±22.3分）与术前（95.7±17.5分）比较差异有统计学意义（P<0.05）。术前Cobb角为22.3°±3.6°,术后Cobb角矫正至5.2°±1.2°,末次随访时为6.0°±2.3°,丢失0.8°±1.5°;术前椎体高度（56.4±5.8）%,术后椎体高度恢复至（95.3±2.9）%,末次随访时为（91.4±3.7）%,丢失（4.0±2.5）%。3例出现椎旁静脉骨水泥栓塞,无明显症状,无内固定断裂。结论：后路短节段椎弓根螺钉固定联合椎体成形术能够有效恢复并维持伤椎高度,减少后凸畸形矫正丢失及内固定失败的发生,具有良好的疗效。     

使用自制植骨漏斗经伤椎植骨联合经皮椎弓根螺钉内固定术治疗胸腰椎骨折的临床疗效

【摘要】 目的：探讨使用自制微创经皮植骨漏斗进行伤椎植骨联合经皮椎弓根螺钉内固定术治疗胸腰椎骨折的临床疗效。方法：回顾性分析自2020年1月～2021年6月收治的26例无神经损伤的胸腰椎骨折患者临床资料。男13例,女13例,年龄51.23±9.56岁（33～65岁）;均为单节段损伤,T12 2例,L1 8例,L2 8例,L3 5例,L4 3例。采用跨伤椎经皮椎弓根螺钉复位内固定,再通过自制的微创经皮植骨漏斗进行伤椎内空腔内植骨（自体髂骨）。记录患者手术时间、术中出血量和并发症发生情况,观测患者术前、术后1周及末次随访时疼痛视觉模拟评分（visual analogue score,VAS）、Oswestry功能障碍指数评分（Oswestry disability index,ODI）、伤椎前缘高度压缩比、伤椎中部高度压缩率及矢状面Cobb角情况,并进行统计学分析。结果：所有患者手术顺利完成,随访时间为15.19±2.51个月（12~22个月）,手术时间84.62±12.88min,出血量55.58±12.44mL,无伤口感染、脊髓损伤等并发症,1例患者出现1枚椎弓根螺钉尾冒松动脱落。术后1周及末次随访时患者伤椎椎体前缘高度压缩率[（6.89±7.25）%、（10.28±7.50）%]、椎体中部高度压缩率[（7.11±5.75）%、（10.63±6.24）%]、Cobb角（4.38°±7.77°、2.14°±7.78°）、VAS评分（3.35±0.56、1.73±0.45）和ODI[（41.96±3.82%、13.77±2.42）%]较术前明显改善（P<0.05）,末次随访时伤椎椎体前缘高度压缩率[（10.28±7.50）%]、椎体中部高度压缩率[（10.63±6.24）%]较术后1周轻度增加,Cobb角（2.14°±7.78°）较术后1周略有下降（P<0.05）,末次随访时患者VAS评分（1.73±0.45）和ODI[（13.77±2.42）%]较术后1周好转（P<0.05）。结论：对于无神经损伤的胸腰椎骨折患者,使用自制微创经皮植骨漏斗进行伤椎植骨联合经皮椎弓根螺钉内固定手术治疗可有效恢复椎体高度,矫正后凸畸形。     

骨水泥加强椎弓根螺钉内固定治疗伴骨质疏松症的腰椎退行性病变

目的 探讨应用聚甲基丙烯酸甲酯(PMMA)骨水泥行椎体加强后椎弓根螺钉内固定治疗伴骨质疏松症的腰椎退行性病变的临床效果.方法 选取本科2004年6月～2009年1月收治的随访资料完整的伴骨质疏松症的腰椎退行性病变患者38例,男16例,女22例;年龄为52～76岁,平均62.5岁.其中腰椎管狭窄症16例,腰椎间盘突出症并节段不稳12例,退行性腰椎滑脱症6例,腰椎退行性侧凸4例.根据患者临床表现及影像学资料确定减压、融合节段和方法,采用PMMA骨水泥强化的椎弓根钉棒系统进行内固定、矫形.采用ODI评分、腰痛及腿痛VAS评分、术后影像学资料评定治疗效果.结果 本组病例术后随访时间18～48个月,平均36.5个月.患者腰痛及下肢疼痛症状均明显缓解,复查X线片均未发现椎弓根螺钉的松动或脱出,椎弓根螺钉周围未发现有透亮线出现.末次随访时,腰痛VAS评分由术前的7.46±2.24减至3.15±1.47(P<0.01),腿痛VAS评分由术前的7.24±2.32减至2.11±0.84(P<0.01).ODI评分由术前的43.15±5.72下降至15.41±16.42(P<0.01).出现术中、术后并发症16例次,未造成机体残余损害.结论 对于伴骨质疏松症的腰椎退行性病变患者,应用PMMA行椎体加强椎弓根螺钉固定,能增强螺钉的稳定性,防止螺钉的松动或脱出,有助于临床疗效的改善和保持.     

骨水泥螺钉与可膨胀椎弓根螺钉治疗严重骨质疏松腰椎病手术的比较

[目的]对比可灌注椎弓根骨水泥螺钉与可膨胀椎弓根螺钉应用于严重骨质疏松老年患者腰椎退变疾病手术的临床效果。[方法]选择本院2012～2015老年腰椎退变疾病合并严重骨质疏松患者30例;完善术前X线片、CT及MRI检查后,15例行经皮可灌注骨水泥螺钉固定+Mis-TILF减压手术技术,另15例行可膨胀螺钉固定+Mis-TILF减压手术技术。分别记录术前、术后VAS评分、JOA评分以及椎弓根钉松动率并进行统计分析。[结果]所有患者均顺利手术,术中均未出现神经损伤、骨水泥渗漏。所有患者随访1年以上。VAS评分随术后时间延长而逐渐减小、JOA评分随术后时间延长而逐渐增加,不同时间点间的差异均有统计学意义(P0.05)。随访中均未见螺钉断钉、断棒现象。可灌注椎弓根骨水泥螺钉组所有患者椎弓根螺钉未见松动现象,可膨胀椎弓根螺钉组有2例患者椎弓根钉出现不同程度松动,占可膨胀螺钉组13.3%,两组椎弓根钉松动率差异有统计学意义。[结论]微创下中空可灌注骨水泥螺钉应用于老年严重骨质疏松患者,在术后恢复过程中效果更可靠,固定更牢固,不易松动,可为老年微创手术患者提供稳定有效的脊柱内固定。     

膨胀式椎弓根螺钉结合骨水泥强化钉道在严重骨质疏松脊柱手术中的应用

目的 探讨膨胀式椎弓根螺钉结合骨水泥强化钉道在治疗严骨质疏松性脊柱内固定手术中的早期疗效。方法 自2006年10月至2008年10月对20例需行内固定治疗同时合并严重骨质疏松的腰椎疾病患者采用膨胀式椎弓根螺钉结合骨水泥强化钉道进行脊柱后路稳定手术,其中男9例,女11例;年龄43～73岁,平均59岁。分别于术后1周、3个月、6个月、12个月及24个月摄动力位X线片及CT扫描,了解螺钉稳定性、骨水泥分布及脊柱融合情况。术前及术后3个月时应用日本矫形外科协会(JOA)不腰痛评分及视觉模拟评分(VAS)评价疗效。结果 本组共置人膨胀式椎弓根螺钉168枚。所有患者术后获12～ 38个月（平均26个月）随访。术前及术后3个月JOA评分平均分别为(11.4±2.6)分和(24.9±1.6)分,差异有统计学意义(t= 19.776,P=0.000);术前及术后3个月VAS评分分别为(7.0±1.4)分和(2.1±1.3)分,差异有统计学意义(t=11.470,P=0.000)。螺钉及骨水泥在椎体内位置稳定,周围骨小梁致密,未见明显透光带,无内固定松动移位迹象;后外侧融合节段植骨愈合良好,椎体间或椎板、关节突及棘突旁有连续性骨小梁形成,连接上下椎体。临床症状明显缓解,无早期及晚期感染等并发症发生,无临床复发。结论 对于合并严重骨质疏松的脊柱后路内固定手术,膨胀式椎弓根螺钉结合骨水泥强化钉道的方法能够极大地提高螺钉固定的稳定性。     

骨水泥在椎体骨折线内弥散情况对椎体成形术治疗效果的影响

【摘要】 目的：探讨经皮椎体成形术（PVP）中骨水泥在椎体骨折线内弥散情况对疗效的影响。方法：回顾性研究2009年9月~2011年12月因骨质疏松性椎体压缩骨折（OVCF）住院并行PVP治疗的45例患者,男14例,女31例,年龄53~88岁,平均72.18岁,病程2h~4个月,平均17.36d。均为胸腰段（T10~L2）单一椎体骨折。根据术前多平面重建CT或MRI评估椎体骨折线位置,参考术后X线、多平面重建CT判断骨水泥在椎体骨折线内的弥散情况,将患者分成两组,A组（n=30）：骨水泥充分弥散在骨折线内,B组（n=15）：骨水泥在骨折线内弥散不佳。记录术前、术后3d及末次随访时的疼痛视觉模拟评分（visual analogue scale,VAS）、Oswestry功能障碍指数（Oswestry disability index,ODI）及局部后凸Cobb角,末次随访时与术后3d局部Cobb角之差定义为后凸纠正丢失量,对比分析两组上述指标的差异,并记录相关并发症。结果：所有患者均顺利完成椎体成形术,无严重并发症出现。除骨密度外两组患者术前基线特征无显著性差异,术后3d及末次随访时的VAS评分、ODI均较术前明显改善（P<0.05）,术后3d时的VAS评分、ODI相比术前值的改善程度（术前-术后）A组优于B组（VAS：5.03±1.33 vs 3.53±1.13,ODI：26.17±2.10 vs 24±2.03,P<0.05）,末次随访时的VAS评分、ODI两组无显著性差异（P＞0.05）。两组术后3d局部Cobb角均较术前明显纠正（P＜0.05）,A组术后3d时的Cobb角与末次随访时无显著性差异（P＞0.05）,B组末次随访时的后凸Cobb角较术后3d时显著增大（P＜0.05）。A组后凸纠正丢失量显著小于B组（1.08°±0.38° vs 3.58°±0.37°,P＜0.05）。A组8例出现骨水泥渗漏,B组6例出现骨水泥渗漏,总体渗漏率为31.1%,骨水泥渗漏均未引起临床症状。结论：PVP可有效缓解胸腰段骨OVCF患者的疼痛,改善功能障碍;骨水泥在骨折线内弥散不佳会影响近期疗效,也可能是骨折椎体接受PVP术后仍发生进展性后凸畸形的危险因素。     

3D打印体外导板辅助经皮椎弓根螺钉固定术治疗胸腰椎骨折的临床疗效观察

【摘要】 目的：观察3D打印体外导板辅助经皮椎弓根螺钉固定术治疗胸腰椎骨折的临床疗效。方法：回顾性分析2017年8月~2020年8月行经皮椎弓根螺钉固定手术的47例胸腰椎骨折患者的临床资料,男13例,女34例;年龄21~69岁。均为单节段损伤,T12 11例,L1 26例,L2 7例,L3 2例,L4 1例。22例术前制作3D打印个体化体外导板,模拟置钉,术中辅助置钉（导板组）;25例采用X线透视辅助下徒手置钉（徒手组）。对比两组手术时间、置钉时间、术中X线透视次数、术中出血量、术后并发症;采用Neo分级标准评价两组手术置钉等级,计算置钉准确率;在术前、术后X线片上测量骨折椎体前缘高度和Cobb角,计算椎体矢状面指数,评价骨折复位及矫正情况;术前和术后1d、7d及1年时进行疼痛视觉模拟评分（visual analogue scale,VAS）评分、日本骨科协会（Japanese Orthopedics Association,JOA）评分和Oswestry功能障碍指数（Oswestry disability index,ODI）评定。结果：导板组手术时间、置钉时间、术中X线透视次数、术中出血量分别为63.57±12.18min、23.69±3.63min、15.26±4.15次、48.82±13.72ml;徒手组分别为85.56±16.27min、41.36±8.12min、26.93±6.93次和74.35±18.64ml;导板组均少于徒手组,差异有统计学意义（P<0.05）。导板组0级置钉119枚,1级置钉3枚,置钉准确率为97.54%;徒手组0级置钉128枚,1级置钉10枚,2级置钉1枚,置钉准确率为92.09%,导板组置钉准确率高于徒手组,差异有统计学意义（P<0.05）。术后两组的椎体前缘高度、椎体矢状面指数和Cobb角与术前相比均有显著性改善（P＜0.05）;两组同时间点比较均无统计学差异（P＞0.05）。两组术后VAS评分、JOA评分和ODI与术前比较均有显著性改善,差异有统计学意义（P<0.05）,两组间同时间点比较均无统计学差异（P＞0.05）。两组患者术后伤椎均达到骨性愈合,均未出现术后并发症。结论：3D打印体外导板辅助经皮椎弓根螺钉固定术治疗单节段胸腰椎骨折可取得良好效果,与徒手经皮椎弓根螺钉固定术相比能够显著性提高置钉准确率,并缩短手术时间、减少术中辐射暴露。     

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.     

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.