后路减压结合Dynesys动态内固定治疗腰椎退变性疾病的中期疗效

目的:评估后路减压结合Dynesys动态内固定治疗腰椎退变性疾病的中期疗效.方法:回顾分析2008年7月～2010年5月采用后路减压结合Dynesys动态内固定治疗的腰椎退变性疾病患者59例,其中腰椎管狭窄症38例,腰椎间盘突出症21例.记录患者术前、术后3个月及末次随访时Oswestry功能障碍指数(ODI)和疼痛视觉模拟量表(VAS)评分,测量术前、术后3个月及末次随访时手术节段活动度(ROM)、椎间高度及上位相邻节段ROM,评估上位相邻节段影像学和症状学退变的发生情况.结果:55例患者获得完整随访,随访48～70个月,平均54个月.术后3个月和末次随访时的ODI分别为(24.1±5.7)％和(15.9±6.3)％,均较术前的(56.3±16.4)％明显改善(P＜0.05).术后3个月和末次随访时的VAS评分分别为2.9±1.5和1.4±0.5,均较术前的6.7±2.7明显改善(P＜0.05).手术节段ROM由术前的(7.6±2.5)°保留至术后3个月的(4.5±2.8)°以及末次随访时的(4.9±2.3)°(P＜0.05).手术节段椎间高度在术后3个月为13.4±2.6mm,较术前12.3±2.7mm明显升高(P＜0.05);末次随访时为12.1±3.2mm,与术前差异无统计学意义(P＞0.05).上位相邻节段ROM由术前的(8.1±3.0)o增加至术后3个月的(9.3±3.2)°,至末次随访时达到(10.0±2.9)°(P＜0.05).末次随访时,7例(12.7％)患者出现上位相邻节段影像学退变,1例患者出现上位相邻节段症状学退变而接受二次Dynesys内固定手术.结论:后路减压结合Dynesys动态内固定能够获得良好的中期临床疗效.在中期随访时,Dynesys动态内固定能够保留手术节段部分活动度,存在一定程度的相邻节段退变.     

Dynesys非融合术后腰椎节段放射学改变及椎间盘再水化

[目的]分析Dynesys动态固定术后腰椎节段的放射学变化和残留椎间盘的再水化现象。[方法]回顾性分析2011年12月~2013年10月在本院接受Dynesys动态固定的38例腰椎间盘退行性疾病患者资料,记录患者术前,术后10 d,末次随访时VAS、ODI评分,采用腰椎X线片测量椎间隙前后缘高度、腰椎前凸角及屈伸活动度(range of motion,ROM),利用腰椎MRI计算手术节段椎间盘平均标准椎间盘信号(calibrated disc signal,CDS)。[结果]38例患者术后平均随访(25.11±6.96)个月。末次随访时,患者腰腿痛VAS评分和ODI指数较手术前后明显改善(P0.05)。手术节段椎间隙前、后缘高度较手术前后均明显降低(P0.05)。上位邻近节段椎间隙前缘高度与术前比较差异无统计学意义(P=0.47),后缘高度较手术前均显著下降(P0.05),平均丢失(10.34±9.81)%。下位邻近节段椎间隙前后缘高度及腰椎前凸角均无显著变化。手术节段屈伸ROM比术前明显减少(P0.05),但仍保留术前ROM的64.11%;相邻节段及腰椎整体ROM较术前差异无统计学意义。23例患者接受腰椎MRI复查,平均CDS由术前(42.74±13.15)%改善至(47.69±14.38)%,差异有统计学意义(P=0.004)。[结论]Dynesys非融合术后残留椎间盘出现再水化,表明其可能具有促进退变椎间盘修复的作用。该系统保留了固定节段一定ROM,不引起邻近节段过度活动。但是术后存在手术节段椎间隙高度丢失以及上位邻近节段代偿性前凸等问题。     

K-ROD系统治疗腰椎间盘突出伴相邻节段退变的疗效

目的探讨K-ROD系统治疗腰椎间盘突出伴相邻节段退变的临床疗效。方法将20例腰椎间盘突出伴相邻节段退变的患者按照手术方式的不同分为观察组(采用K-ROD系统治疗,11例)和对照组(采用单节段后路椎体间融合治疗,9例)。观察两组手术情况、临床疗效(腰、腿部疼痛VAS评分和功能障碍指数)和影像学指标(椎间隙高度和椎间活动度)。结果患者均获得随访,观察组随访时间34~53(44.55±6.52)个月,对照组随访时间31~54(40.22±9.26)个月。①手术时间、术中出血量观察组明显长(多)于对照组(P<0.05)。②临床疗效:术后1年、末次随访时两组均较术前明显改善(P<0.05);末次随访时观察组各项指标均明显优于对照组(P<0.05)。③影像学指标:术后1年椎间隙高度两组比较差异无统计学意义(P>0.05),末次随访时观察组椎间隙高度明显高于对照组(P<0.05);术后1年、末次随访时与术前比较,观察组退变椎间盘节段椎间活动度(ROM 1)均降低(P<0.05),退变椎间盘上位相邻节段椎间活动度(ROM 2)均增高(P<0.05),对照组ROM 1、ROM 2均增高(P<0.05),ROM 1两组间比较差异均有统计学意义(P<0.05)。末次随访时出现邻椎退变观察组1例、对照组7例,两组比较差异有统计学意义(P<0.05)。结论K-ROD系统用于治疗腰椎间盘突出伴相邻节段退变临床疗效较好,可延缓手术相邻节段椎间盘的退变。     

Dynesys动态内固定与融合术治疗L4/5单节段退变疾病的疗效对比

目的:评估Dynesys内固定或融合术治疗L4/5单节段腰椎退变疾病的临床疗效.方法:回顾分析2008年7月～2012年7月收治的L4/5单节段退变疾病患者76例,其中采用Dynesys动态固定35例(Dynesys组),融合术41例(融合组),随访时间均大于2年.评价指标采用Oswestry功能障碍指数(ODI),疼痛视觉模拟评分(VAS),手术节段及上端、下端邻近节段椎间高度及活动度(ROM),邻近节段椎间盘Pfirmman分级,并应用UCLA系统来评价邻近节段退变情况.结果:两组末次随访时的ODI及VAS评分均较术前明显改善(P＜0.05),两组间比较差异无统计学意义(P＞0.05).两组手术节段椎间高度术前无显著性差异,末次随访时Dynesys组较术前无明显变化,融合组明显增高(P＜0.05),两组间差异有统计学意义(P＜0.05).邻近节段椎间高度术前及末次随访时两组间比较差异均无显著性(P＞0.05).术前上端邻近节段ROM在Dynesys组为8.3°±2.1°,融合组为8.4°±1.5°,末次随访时Dynesys组为10.2°±2.2°,融合组为12.9°±2.1°,均较术前增加(P＜0.05),组间差异有统计学意义(P＜0.05).术前下端邻近节段ROM两组间差异无显著性,末次随访时融合组较术前明显增加(P＜0.05),但组间差异无显著性(P＞0.05).两组术前Pfirrmann分级无统计学差异,末次随访时Pfirrmann分级变化组内有统计学差异(P＜0.05),但组间仅上端邻近节段差异有统计学意义(P＜0.05).根据UCLA系统评分标准,Dynesys组8个节段出现影像学邻近节段退变,融合术组为22个节段,两组间差异有统计学意义(P＜0.05).仅融合术组有1例患者出现症状学邻近节段退变,行二次手术治疗.结论:Dynesys动态固定或融合术治疗单节段腰椎退变疾病均可取得满意临床疗效,前者在预防邻近节段退变方面更有优势.     

后路减压Dynesys动态内固定术治疗腰椎退变性疾病的长期疗效

目的 :评估后路减压Dynesys动态内固定治疗腰椎退变性疾病的长期临床疗效。方法 :收集2008年7月～2013年12月在我院采用后路减压Dynesys动态内固定治疗的腰椎退变性疾病患者的临床资料,其中163例患者获得78～144个月(95.4±15.6个月)随访,男97例,女66例;年龄31～60岁(43.5±11.7岁)。单节段固定117例,双节段固定42例,三节段固定4例。比较患者术前、术后3个月和末次随访时的Oswestry功能障碍指数(Oswestry disability index,ODI)和腰腿痛视觉模拟量表(visual analogue scale,VAS)评分;在术前、术后3个月和末次随访时的腰椎正侧位和前屈后伸位X线片上测量手术节段和上位邻近节段活动度(range of motion,ROM)及椎间高度,评估影像学和症状学邻近节段退变(adjacent segment degeneration,ASD)发生情况以及内固定相关并发症。结果:术后3个月及末次随访时的ODI和VAS评分均较术前显著性改善(P0.05),末次随访时与术后3个月时比较差异亦有统计学意义(P0.05)。术前、术后3个月和末次随访时手术节段的ROM分别为7.8°±2.1°、4.6°±1.4°和3.9°±1.5°,手术节段椎间高度分别为12.1±2.9mm、12.8±3.5mm和10.9±2.8mm,上位邻近节段ROM分别为8.3°±1.9°、9.2°±2.7°和10.2°±2.8°,术后3个月及末次随访时与术前比较、末次随访时和术后3个月比较均有统计学差异(P0.05);上位邻近节段椎间高度分别为12.7±3.1mm、12.6±3.2mm和12.1±2.8mm,差异均无统计学意义(P0.05)。末次随访时32例(19.6%)患者手术节段ROM小于4°(临床融合组),131例(80.4%)大于4°(非融合组),两组患者术前、术后3个月和末次随访时的VAS评分和ODI均无统计学意义(P0.05)。末次随访时30例(18.4%)患者出现影像学ASD;2例(1.2%)患者出现症状学ASD,其中1例行翻修手术,另1例行保守治疗。1例患者术后2个月出现术区深部感染,抗感染治疗后痊愈;6例患者在术后5年随访时出现单侧螺钉松动,均未行手术治疗。2例患者出现椎弓根螺钉断裂,无不适症状未给予翻修手术。所有患者均无手术节段症状复发。结论:后路减压Dynesys动态内固定治疗腰椎退变性疾病可获得良好的长期临床疗效,并能保留手术节段部分活动度。     

Dynesys非融合技术治疗腰椎间盘突出症8年临床随访

背景:Dynesys动态稳定系统是非融合技术最常见的手术方式之一,短期临床疗效满意,但长期疗效鲜有报道。目的:探讨Dynesys非融合技术治疗腰椎间盘突出症的长期疗效。方法:回顾性分析2008年2月至2011年2月因腰椎间盘突出症接受Dynesys非融合技术治疗的71例患者的临床资料。收集患者术前、术后4年及末次随访的临床及影像学资料,包括疼痛视觉模拟评分(VAS)、日本骨科协会评分(JOA)、Oswestry功能障碍指数(ODI)、手术节段及邻近节段椎间活动度、椎间隙高度、椎间盘退变Pfirrmann分级。结果:最终64例纳入分析,随访时间8.2~9.3年,平均(8.8±0.3)年。术后4年及末次随访时,腰痛及腿痛VAS评分、JOA评分、ODI较术前明显改善(P<0.05);手术节段椎间活动度,与术前比较,显著降低(P<0.05);手术节段椎间隙高度,与术前比较,差异无统计学意义(P>0.05);上位邻节段椎间隙高度较术前有所降低,活动度有所增加,但差异无统计学意义(P>0.05)。术后各随访时间点手术节段以及上位邻近节段椎间隙高度、椎间活动度差异均无统计学意义(P>0.05)。Pfirrmann分级显示,术后4年时手术节段总改善率为41.1%,无明显改变率为54.8%,退变加重率为4.1%;邻近节段的退变加重率为12.6%。末次随访时,手术节段总改善率为22.9%,无明显改变率为69.9%,退变加重率为6.9%;邻近节段的退变加重率为17.2%。随访期间1例发生椎间盘突出复发,其余未见螺钉松动、断裂、失效等相关并发症。结论:Dynesys非融合技术治疗腰椎间盘突出症,在长期随访中可以有效缓解腰痛及腿痛,并在保证脊柱稳定性的前提下,保留手术节段一定的椎间活动度,可延缓邻近节段退变的进程,从而获得满意的长期临床疗效。     

颈前路减压零切迹椎间融合器与传统钛板固定融合术后相邻节段退变的比较

目的 :比较颈前路减压零切迹椎间融合器(Zero-P)与传统钛板内固定融合术治疗单/双节段脊髓型颈椎病对术后相邻节段退变的影响。方法:回顾性分析2015年1月～2018年3月采用颈前路减压Zero-P与传统钛板内固定融合术治疗的113例脊髓型颈椎病患者的资料,其中Zero-P组(A组)65例,传统钛板组(B组)48例,A组再分为单节段组(n=44)和双节段组(n=21),B组再分为单节段组(n=28)和双节段组(n=20),4组患者年龄、性别构成比、手术节段均无统计学差异(P0.05)。比较两种术式的手术时间、术中出血量,以及4组的术前、末次随访时的日本骨科协会(Japanese Orthopaedie Association,JOA)评分、疼痛视觉模拟评分(visual analog scale,VAS),末次随访时评估患者术后是否出现吞咽困难,并在颈椎侧位X线片上测量术前、术后即刻、末次随访时相邻节段椎间隙高度,评估术前、末次随访时的相邻椎体骨化情况,在颈椎MRI上应用椎间盘Pfirrmann分级评估术前、末次随访时的相邻节段椎间盘退变情况。结果:单节段A组随访时间为18.0±7.9个月,单节段B组为15.8±8.8个月,双节段A组为14.8±6.4个月,双节段B组为15.8±8.2个月,4组间无统计学差异(P0.05)。A组手术时间较B组明显缩短(P0.05),术中出血量两组无明显差异(P0.05)。4组患者末次随访时的JOA评分、VAS评分较术前均有明显改善(P0.05),同节段A、B组间比较JOA评分改善率无明显差异(P0.05),术前、末次随访时同节段A、B组间比较VAS评分无明显差异(P0.05)。双节段B组末次随访时上、下相邻椎间隙高度较术前、术后均有明显下降(P0.05),其余3组末次随访时上、下相邻椎间隙高度较术前、术后均无明显差异(P0.05)。末次随访时,双节段B组上、下相邻椎间隙高度显著低于双节段A组(P0.05),单节段A、B组末次随访时上、下相邻椎间隙高度无明显差异(P0.05)。末次随访时,相邻椎体骨化发生率单节段B组(32.14%)与单节段A组(6.82%)比较、双节段B组(40%)与双节段A组(9.52%)比较更高(P0.05)。根据Pfirrmann分级,双节段B组(30%)比双节段A组(4.76%)更容易发生相邻节段椎间盘退变(P0.05),单节段A、B组末次随访时相邻节段椎间盘退变无明显差异(P0.05);B组中双节段(30%)比单节段(7.14%)更容易发生相邻节段椎间盘退变(P0.05),A组中单、双节段末次随访时相邻节段椎间盘退变无明显差异(P0.05)。B组的术后吞咽困难发生率均比A组高(P0.05)。结论:颈前路单/双节段减压内固定融合手术治疗脊髓型颈椎病中,使用Zero-P与传统钛板内固定融合相比,临床疗效无明显差异,但Zero-P可减少术后相邻节段退变,且在双节段比较中优势更明显。     

Topping-off手术治疗腰椎退行性疾病的影像学分析

目的:评价Topping-off手术治疗连续双节段腰椎退行性疾病的影像学改变。方法 :2008年8月~2012年12月,35例连续双节段腰椎退行性椎管狭窄症(其中上位病变节段为轻或中度退变)患者在我院接受手术治疗。其中男23例,女12例,年龄62.6±18.9岁(30~79岁)。所有患者均接受腰椎单节段融合(PLIF)+上位节段棘突间动态稳定(置入Coflex)手术(Topping-off手术),其中L4/5置入Coflex+L5/S1融合14例,L3/4置入Coflex+L4/5融合21例。回顾性分析患者术前及末次随访时X线片上Coflex置入节段及其上位相邻节段的椎间隙高度、椎间活动度、椎体偏移、椎间隙角及腰椎前凸角;在MRI上对Coflex置入节段和其上位相邻节段椎间盘退变情况进行改良Pfirrmann分级。结果:患者均安全完成手术,手术时间为112±21min(95~155min),出血量为403±111ml(300~520ml)。均未出现硬脊膜破裂、神经损伤等相关并发症。随访24.8±12.8个月(11~65个月)。术后末次随访时Coflex置入节段及其上位相邻节段椎间隙前缘高度、椎间隙后缘高度与术前比较均无统计学意义(P0.05);Coflex置入节段椎间隙角较术前显著性增大(t=-1.8,P0.05);Coflex上位相邻节段椎间隙活动度(过伸位角度-过屈位角度)、椎间隙角及腰椎前凸角与术前比较均无统计学意义(P0.05)。24例随访2年以上患者MRI检查显示Coflex置入节段及其上位相邻节段椎间盘的改良Pfirrmann分级情况与术前相同。结论:Topping-off手术可以保持Coflex置入节段良好的稳定性,并保留该节段部分运动功能及其上位相邻节段节段正常活动,减少了上位相邻节段退变发生的危险因素。     

腰椎Activ L人工椎间盘置换术后影像学表现与临床疗效的相关性分析

目的:探讨腰椎Activ L人工椎间盘置换术后的影像学表现与临床疗效的相关性。方法:2009年3月~2012年3月,应用Activ L假体对32例腰椎间盘退变性疾患的患者进行人工椎间盘置换术,其中30例患者共36个假体获得12~46个月(平均28.8个月)的随访,随访2年以上者20例(其中随访3年以上15例)。均在术前和末次随访时进行腰、腿痛VAS评分和Oswestry功能障碍指数(ODI)评分,同时测量手术节段和上、下相邻节段的活动度、椎间隙高度及腰椎前凸角。对术前及末次随访时的VAS评分、ODI评分,手术节段和上下相邻节段的活动度、椎间隙高度以及腰椎前凸角分别进行配对t检验,分别以每例患者末次随访时的VAS评分和ODI评分为应变量,以末次随访时的活动度、椎间隙高度以及腰椎前凸角为自变量,进行相关性分析。结果:末次随访时的腰痛VAS评分、腿痛VAS评分和ODI评分与术前比较均有显著改善(P0.0001)。末次随访时,手术节段、上位相邻节段活动度明显增加(P0.05),而下位相邻节段活动度无明显变化(P0.05);手术节段及其上、下相邻节段椎间隙高度与术前比较均无明显变化(P0.05);腰椎前凸角与术前比较无明显变化(P0.05)。末次随访时,手术节段、上下相邻节段的活动度和椎间隙高度及腰椎前凸角与VAS评分和ODI评分均无明显相关性(r0.2138,P0.05)。结论:腰椎Activ L人工椎间盘置换术治疗腰椎间盘退变性疾患的近中期疗效满意,近中期随访时手术节段、上下位相邻节段的活动度和椎间隙高度与临床疗效无明显相关性。     

Dynesys动态内固定与融合术治疗腰椎退变疾病的对比研究

目的 比较Dynesys动态内固定与腰椎后路椎间融合术（posterior lumbar interbody fusion,PLIF）治疗腰椎退变疾病的临床疗效和影像学结果.方法回顾分析2008年7月-2011年3月采用Dynesys 动态固定治疗且随访时间＞2年的腰椎退变患者46例（Dynesys组）,以同期行PLIF的50例患者作为对照（PLIF组）.记录2组手术前后Oswestry 功能障碍指数（Oswestry disability index,ODI）和疼痛视觉模拟量表（visual analogue scale,VAS） 评分,摄腰椎正侧位和前屈后伸位X线片,测量手术节段椎间高度、活动度（range of motion,ROM）以及近侧邻近节段的椎间ROM,评估2组影像学和症状学邻近节段退变的发生情况.结果 2组患者术前资料差异无统计学意义,末次随访时的ODI及VAS评分均较术前明显改善（P＜0.05）,组间差异无统计学意义（P＞0.05）.末次随访时Dynesys组手术节段椎间高度较术前轻度升高（P＞0.05）,而PLIF组显著升高（P＜0.05）且大于Dynesys组,组间差异有统计学意义（P＜0.05）.Dynesys组手术节段ROM由术前的7.1°降至末次随访时的4.9°（P＜0.05）,而PLIF组手术节段ROM由术前的7.3°降至末次随访时的0°（P＜0.05）.2组近侧邻近节段椎间高度变化差异无统计学意义（P＞0.05）,ROM在末次随访时均较术前有所增加（P＜0.05）,且PLIF组大于Dynesys组（P＜0.05）.Dynesys组有6例患者出现影像学邻近节段退变,PLIF组患者有15例出现影像学邻近节段退变,差异有统计学意义（P＜0.05）,仅PLIF组有1例出现症状学邻近节段退变,行二次手术治疗.结论 Dynesys动态内固定与融合术均获得良好临床疗效.与融合术相比,Dynesys动态内固定能够保留手术节段部分ROM,邻近节段椎间ROM的增幅及邻近节段退变发生数均较低.     

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.