腰椎滑脱症术后脊柱骨盆矢状面参数变化与临床疗效的相关性分析

目的观察退行性腰椎滑脱症患者术后脊柱骨盆矢状面参数变化,并评估术后疗效,探讨脊柱骨盆矢状面参数变化与临床疗效的相关性。方法纳入自2015-06—2017-01行后路腰椎椎体间融合术(PLIF)的30例L4、5退行性腰椎滑脱症。测量手术前后脊柱骨盆矢状面参数:骨盆入射角(PI)、骨盆倾斜角(PT)、骶骨倾斜角(SS)、腰椎前凸角(LL)、滑脱程度(SD)、椎间隙高度(DH)。采用Pearson相关分析脊柱骨盆矢状面参数与ODI指数、VAS评分的相关性。结果本组30例均获得3~19(12.73±7.06)个月随访。末次随访时VAS评分、ODI指数、PT、SS、LL、SD、DH较术前明显改善,差异有统计学意义(P0.05);而PI与术前比较差异无统计学意义(P0.05)。Pearson相关分析显示,术前PT、SD与术前ODI指数、VAS评分呈正相关,SS、LL、DH与ODI指数、VAS评分呈负相关,而PI与ODI指数、VAS评分无明显相关性。手术前后PT、SS、LL、SD、DH的变化值与ODI指数及VAS评分改善率呈正相关。结论退行性腰椎滑脱症患者术后脊柱骨盆矢状面参数改变与临床疗效存在相关性,术中应尽可能恢复脊柱骨盆矢状面平衡以获得良好疗效。     

腰椎滑脱症融合术后脊柱矢状面平衡改变与疗效的关系

目的探讨经椎间孔腰椎椎间融合术(TLIF)单节段及双节段固定对退行性腰椎滑脱症患者脊柱矢状面参数的影响及其与疗效的关系。方法收集南京医科大学第一附属医院44例(Ⅰ度32例,Ⅱ度12例)经TLIF治疗的退行性腰椎滑脱症患者的临床及影像学资料,根据手术固定节段分为单节段组(29例)和双节段组(15例)。分析比较术前、术后全脊柱侧位X线片的矢状面参数脊柱骶骨角(SSA)、T_1骨盆角(TPA)、腰椎前凸(LL)、骨盆投射(PI)、骨盆倾斜(PT)及骶骨倾斜(SS),以及疼痛视觉模拟量表(VAS)评分、日本骨科学会(JOA)评分及Oswestry功能障碍指数(ODI)。结果全部病例均获得随访,随访时间3~10个月,平均6个月。全组患者术后SSA、TPA、LL、SS均较术前增大,PT较术前减小,差异均有统计学意义(P0.05),VAS评分、JOA评分和ODI均较术前改善,差异均有统计学意义(P0.05)。单节段组手术前后LL差值、ODI差值与双节段组比较差异有统计学意义(P0.05),且2组手术前后LL差值与ODI差值均相关。SSA差值在双节段组与VAS评分差值相关,在单节段组二者无相关性。结论Ⅰ度或Ⅱ度退行性腰椎滑脱症患者通过TLIF治疗可改善脊柱矢状面参数,且单节段固定更有利于术后脊柱矢状面参数的改善。     

L_4 退变性滑脱患者脊柱-骨盆矢状面参数的特点与相关性分析

[目的]探讨L4退变性滑脱患者脊柱-骨盆矢状面参数的特点及各参数之间的相关性。[方法]回顾性分析2011年1月~2014年6月间44例L4单节段退变性滑脱患者的临床资料,并选取41例健康志愿者做为对照。在站立位脊柱侧位X线片上进行矢状面参数的测量(包括骨盆入射角PI、骨盆倾斜角PT、骶骨倾斜角SS、腰椎前凸角LL、矢状面轴向垂直距离SVA及T1骨盆角TPA等)。按PI大小进行分组对比,并观察腰椎矢状面曲度的Roussouly分型。[结果]DS组的PI、PTNC组,SSNC组(P0.05);两组的LL、SVA及TPA差异无统计学意义(P0.05)。在DS组中进一步发现:正常PI亚组的PT、TPA均大于NC组及大PI亚组的相应值,而SS均小于NC组及大PI亚组(P0.05)。按Roussouly分型,NC组中1~4型所占比例分别为9.8%、56.1%、26.8%和7.3%;DS组中1~4型的比例分别为4.5%、25%、43.2%和27.3%。相关性分析显示:两组中均可见PI与PT、SS存在密切相关性(P0.05);而TPA与PI、PT、LL及SVA之间有密切相关性(P0.05)。[结论]L4退变性滑脱患者较正常人群的骨盆入射角更大,且存在骨盆后倾的代偿机制;T1骨盆角是评价患者整体矢状面平衡的理想指标。     

前外侧腰椎间融合术与后路经椎间孔腰椎间融合术治疗L4/5Ⅰ度退变性腰椎滑脱的疗效比较

目的:比较单纯前外侧腰椎间融合术(anterolateral lumbar interbody fusion,ALLIF)与后路经椎间孔腰椎间融合术(transforaminal lumbar interbody fusion,TLIF)治疗Ⅰ度退变性腰椎滑脱的疗效。方法:回顾2013年4月~2015年4月在我院行手术治疗的68例L4/5Ⅰ度退变性腰椎滑脱患者,其中32例行ALLIF,男20例,女12例,年龄51.3±11.9岁(40~65岁);36例行TLIF,男22例,女14例,年龄50.3±8.6岁(42~63岁)。对两组患者的一般资料、围手术期参数、并发症、术前和术后1周、6个月、12个月、24个月的腰痛和腿痛视觉模拟评分(visual analog scale,VAS)、Oswestry功能障碍指数(Oswestry disability index,ODI)和影像学参数[腰椎前凸(LL)、手术节段椎间高度(DH)、手术节段前凸角(SLA)和滑脱百分比(Slip%)]进行比较分析。结果:两组患者的年龄、性别比、体重指数、骨盆指数、术前腰腿痛VAS评分、ODI、影像学参数和随访时间等均无统计学差异(P0.05)。ALLIF组手术时间和出血量分别为69.97±11.06min和133.40±23.71ml,TLIF组分别为106.42±8.47min和249.48±30.16ml,ALLIF组均显著性低于TLIF组(P0.05)。术中未出现大血管损伤、硬膜撕裂、神经功能损害、腹膜撕裂、腹部脏器损伤,术后无切口疝、内固定或假体松动、断裂等并发症。两组术后各时间点的腰痛VAS评分、腿痛VAS评分、ODI均较术前有明显改善(P0.05),两组间同时间点比较均无显著性差异(P0.05)。两组术后各时间点的DH、LL、SLA、Slip%均较术前有显著性改善(P0.05),两组术后各个时间点的Slip%比较均无显著性差异(P0.05),ALLIF组术后各个时间点的DH、LL、SLA均优于同时间点TLIF组(P0.05)。末次随访时两组患者均获骨性融合,ALLIF组5例(15.6%)出现融合器沉降。结论:与TLIF相比,ALLIF治疗Ⅰ度退行性腰椎滑脱同样可以获得满意的临床疗效,并具有手术出血量少、手术时间短,可以更好地恢复椎间隙高度以及腰椎前凸角的优势。     

下腰椎脊柱骨盆参数和PLIF手术对腰椎退行性疾病患者临床疗效的影响

目的探讨下腰椎脊柱骨盆参数和下腰椎后路椎间融合(PLIF)手术对腰椎退行性疾病患者临床疗效的影响。方法选取40例腰椎退行性疾病患者为观察组,另选取同期体检健康人群20例作为对照组。比较两组下腰椎脊柱骨盆矢状位参数:骨盆倾斜角(PT)、骨盆入射角(PI)、骶骨倾斜角(SS)和腰椎前凸角(LL);记录观察组经PLIF术治疗后各下腰椎脊柱骨盆矢状位参数变化以及日本骨科学会(JOA)、Oswestry功能障碍指数问卷(ODI)、脊椎生活质量量表(QLS-DSD)评分,并分析下腰椎脊柱骨盆矢状位参数与JOA、ODI和QLS-DSD的关系。结果观察组中,腰椎间盘突出患者PT显著大于对照组,SS和LL显著小于对照组(P0.05),腰椎滑脱患者PT、PI显著大于对照组,SS和LL显著小于对照组(P0.05),腰椎管狭窄患者各下腰椎脊柱-骨盆矢状位参数与对照组比较,差异无统计学意义(P0.05);经PLIF术治疗后,腰椎滑脱患者PT较术前显著减小(P0.05),SS和LL较术前显著增大(P0.05);所有患者经PLIF术治疗后,JOA评分较术前显著升高(P0.05),ODI和QLS-DSD评分显著降低(P0.05);经相关性分析,腰椎滑脱患者手术前后PT变化与JOA评分呈负相关(P0.05),与ODI和QLS-DSD评分呈正相关(P均0.05),手术前后SS和LL变化与JOA评分呈正相关(P均0.05),与ODI和QLS-DSD评分呈负相关(P均0.05)。结论腰椎退行性病变中腰椎滑脱症患者脊柱骨盆矢状位参数存在明显异常,PLIF术治疗可明显改善腰椎滑脱患者脊柱骨盆矢状位参数和临床症状,且脊柱骨盆矢状位参数的变化与临床疗效相关。     

退变性腰椎侧凸患者矢状面平衡的特点及对腰椎侧凸的影响

目的 :分析退变性腰椎侧凸矢状面平衡参数的特点及其对腰椎侧凸的影响,探讨矢状面平衡参数改变在退变性腰椎侧凸进展中的作用。方法:回顾分析2012年3月～2017年3月经我院诊治的退变性腰椎侧凸患者(病例组)90例,男37例,女53例,年龄51～77岁(57.1±5.8岁)。选取同时期、同年龄段及同性别比的无腰椎侧凸的55例腰椎退行性疾病患者作为照组(对照组),男31例,女24例,年龄50～76岁(56.8±6.1岁)。所有患者均行脊柱全长X线检查,同时填写Oswestry功能障碍指数(Oswestry disability index,ODI)、视觉模拟评分(visual analogue scale/score,VAS)及脊柱侧凸研究学会22项(scoliosis research society-22,SRS-22)量表。测量矢状面平衡相关参数:(1)脊柱参数,脊柱矢状轴(sagittal vertical axias,SVA)、胸椎后凸角(thoracic kypho-sis,TK)、腰椎前凸角(lumbar lordosis,LL)、骶骨倾斜角(sacrum slop,SS);(2)骨盆参数,骨盆入射角(prlbrv in-cidence,PI)、骨盆倾斜角(pelvic tilt,PT);(3)脊柱-骨盆参数,T1骨盆角(T1 pelvic angle,TPA)、L1骨盆角(L1pelvic angle,LPA)。比较两组患者各矢状面平衡参数是否具有统计学差异,分析各矢状面平衡参数与生活质量及腰椎侧凸Cobb角的相关性。结果:两组患者的SVA、TK、PI、PT及TPA差异无统计学意义(P0.05);SS、LL及LPA差异有统计学意义(P0.05)。两组患者ODI、VAS及SRS-22差异有统计学意义(P0.05)。病例组资料相关性分析显示,ODI、VAS及SRS-2与矢状面平衡参数SS、LL及LPA有显著相关性(-1r1,P0.05),与SVA、TK、PI、PT及TPA无显著相关性(P0.05);侧凸Cobb角与LL呈负相关(-1r0,P0.05);与SS及LPA均呈正相关(0r1,P0.05)。进一步回归分析显示,侧凸Cobb角与SS、LL及LPA存在直线回归关系(F=417.331,P0.01),其回归方程为Cobb角=19.526-8.223×LL+3.727×SS+1.618×LPA。结论:退变性腰椎侧凸患者矢状面平衡参数以LL和SS改变为主,表现为LL减小及SS增大并随侧凸的加重而进展,降低了患者的生活质量。     

退变性腰椎侧凸矫形术后腰椎前凸角变化对临床疗效的影响

目的 :评估退变性腰椎侧凸(degenerative lumbar scoliosis,DLS)患者行长节段固定矫形术后腰椎前凸角与脊柱-骨盆矢状位参数匹配与否对临床疗效的影响。方法:对我院2015年6月~2016年6月行腰椎长节段矫形固定术(至少4个椎体)的DLS患者,参照理想腰椎前凸角(lumbar lordosis,LL)=0.6PI+0.4TK+10°,根据出院时LL分为两组,A组(匹配组,术后LL在理想LL±10°范围内)和B组(非匹配组,术后LL在理想LL±10°范围外),利用院内影像归档与通信系统(picture archiving and communication system,PACS)在全脊柱正侧位X线片上测量侧凸Cobb角、冠状位平衡(coronal vertical axis,CVA)、骨盆入射角(pelvic incidence,PI)、骨盆倾斜角(pelvic tilt,PT)、骶骨倾斜角(sacral slope,SS)、腰椎前凸角(lumber lordosis,LL)、胸椎后凸角(thoracic kyphosis,TK)、矢状位平衡(sagittal vertical axis,SVA)等,采用视觉模拟评分(visual analogue scale,VAS)、Oswestry功能障碍指数(Oswestry disability index,ODI)评价患者术后生活质量,随访至少12个月。使用独立样本t检验比较两组影像参数和生活质量评分。结果:共纳入患者100例(A组53例,B组47例),其中男性43例,女性57例,平均侧凸Cobb角为17.5°±7.8°。两组患者随访时间、手术节段、术前侧凸Cobb角、术前的CVA、LL、SS、SVA均无明显差异性(P0.05);术后两组患者的LL、SS、SVA、PT具有明显差异性(P0.01),A组患者LL(42.2°±10.2°)较术前(31.6°±15.5°)明显改善,TK、SS增大,PT减小,术后SVA(17.9±28.5mm)较术前(46.0±37.9mm)明显改善。B组患者术后相关矢状位参数较术前均无明显变化。两组患者术后VAS评分、ODI评分较术前均有明显改善,经3~6个月的短期随访两组患者术后症状评分无明显差异性;经12个月以上随访,A组患者较B组患者腰腿痛VAS评分明显改善(P0.05),ODI评分无明显差异(P=0.08)。结论:退变性腰椎侧凸患者根据公式0.6PI+0.4TK+10°重建腰椎前凸,可以获得满意的脊柱-骨盆矢状位平衡,有助于提高DLS患者术后生活质量。     

青少年L5/S1峡部裂性腰椎滑脱患者脊柱-骨盆矢状面形态分析

目的探讨青少年L_5/S_1峡部裂性腰椎滑脱患者的脊柱-骨盆矢状面形态改变。方法回顾性分析2009年10月—2017年1月收治的29例青少年L_5/S_1峡部裂性腰椎滑脱患者影像学资料,以30例年龄匹配的正常青少年影像学资料作为对照。在站立位全脊柱侧位X线片上测量滑脱角(SA)、滑脱距离(SD)、骨盆入射角(PI)、骨盆倾斜角(PT)、骶骨倾斜角(SS)、骨盆矢状面厚度(SPT)、L_5入射角(L_5I)、腰椎前凸角(LL)、胸椎后凸角(TK)、脊柱矢状位平衡(SVA)、骶骨平台角(STA)、S_1指数、腰骶角(LSA)等脊柱-骨盆矢状面参数,并计算滑脱率(SP),比较滑脱组与对照组以及低滑脱(SP≤17%)与高滑脱(SP17%)亚组之间的差异,并采用Pearson相关检验分析SP与各影像学参数的相关性。结果滑脱组SA为-4.5°±9.6°,SD为(7.1±3.6)mm,SP为(22.2±11.1)%。滑脱组的LSA、STA、S_1指数小于对照组,PI、PT、SS、SPT、L_5I、SVA及LL大于对照组,差异均有统计学意义(P0.05);2组TK差异无统计学意义(P0.05)。高滑脱亚组的SA、TK、LSA、STA及S_1指数均显著小于低滑脱亚组,PI、PT、SS、SPT、L_5I和SVA均大于低滑脱亚组,差异均有统计学意义(P0.05);2个亚组的LL差异无统计学意义(P0.05)。滑脱组PI、PT、SPT、L_5I、LL与SP呈正相关,TK、LSA、STA及S_1指数与SP成负相关,SS、SVA与SP无明显相关性。结论腰骶部先天发育不良可能是青少年峡部裂性腰椎滑脱发生的始动因素。受滑脱程度影响,其脊柱-骨盆矢状面形态显著异常,表现出腰椎前凸增大、躯干前倾,同时骨盆后旋、屈髋屈膝等异常代偿姿势。     

脊柱骨盆矢状面参数对老年退行性腰椎滑脱症患者术后疗效的评估价值

目的 探讨脊柱骨盆矢状面参数对老年退行性腰椎滑脱症(degenerative lumber spondylolisthesis,DLS)患者术后疗效的评估价值。方法 选取本院脊柱外科2017年1月-2018年1月收治的30例老年DLS患者,均行后路腰椎椎体间融合术治疗,于手术前及末次随访时行X线片拍摄,测量骨盆入射角(pelvic incidence,PI)、骨盆倾斜角(pelvic tilt,PT)、骶骨倾斜角(sacral slope,SS)、腰椎前凸角(lumbar lordosis,LL)、滑脱程度(spondylolisthesis degree,SD)、椎间隙高度(disc height,DH)等脊柱骨盆矢状面参数,采用疼痛视觉模拟评分(visual analogue scale,VAS)、功能障碍指数(Oswestry disability index,ODI)评估所有患者术前及末次随访时的疗效,采用Pearson相关性分析探讨脊柱骨盆矢状面参数与ODI指数及VAS评分的相关性。结果 手术后,所有患者的ODI指数、VAS评分均下降,且与手术前比较差异显著(P0.05);所有患者的PT、SD均下降,SS、LL及DH均上升,且与手术前比较差异显著(P0.05); ODI改善率及VAS改善率均与PT、SS、LL、SD及DH变化值呈显著的相关性(P0.05),其中,PT、SD与之呈负相关关系,而LL、SS及DH与之呈正相关关系。结论 脊柱骨盆矢状面参数对老年DLS患者术后疗效具有重要的评估价值,其参数变化与疗效呈明显的相关性。     

后路减压并内固定术治疗退行性脊柱侧凸对脊柱-骨盆矢状面参数和疗效的影响

目的评估后路减压并内固定术对退行性脊柱侧凸(DS)患者术后生活质量和矢状面参数的影响,以及对矢状面重建策略的初步探索。方法 2015年1月-2020年5月,重庆市中医骨科医院采用后路减压并椎弓根螺钉内固定融合术治疗DS患者64例,记录手术时间、术中出血量、术中透视次数、住院时间及并发症发生情况。采用疼痛视觉模拟量表(VAS)评分评估腰痛和下肢痛程度,采用Oswestry功能障碍指数(ODI)评价腰椎功能。术前及末次随访时在标准站立位全脊柱X线片上测量腰椎前凸角(LL)、胸椎后凸角(TK)、胸腰段后凸角(TLK)、骨盆入射角(PI)、骨盆倾斜角(PT)、骶骨倾斜角(SS)、冠状位Cobb角及矢状位垂直轴(SVA)等影像学参数,并评价SVA及PI-LL改善程度对疗效的影响。结果所有手术顺利完成,所有患者随访12~46(22.3±6.2)个月。末次随访时,所有患者腰痛和下肢痛VAS评分和ODI均较术前明显改善,差异有统计学意义(P < 0.05)。末次随访时,长节段内固定患者TLK、PT、冠状位Cobb角、SVA、PI-LL较术前明显减小,LL和SS较术前明显增大;短节段内固定患者PT、冠状位Cobb角较术前减小,SS较术前增大;差异均有统计学意义(P < 0.05)。末次随访SVA ≥ 95 mm的患者腰痛VAS评分和ODI均高于SVA ≤ 50 mm的患者,差异有统计学意义(P < 0.05);PI-LL > 9°患者腰痛VAS评分与PI-LL ≤ 9°患者相比,差异有统计学意义(P < 0.05);PI-LL > 9°患者下肢痛VAS评分及ODI与PI-LL ≤ 9°患者相比,差异无统计学意义(P > 0.05)。结论后路减压并内固定术对DS患者的生活质量和矢状面参数均有较好的改善作用,国人中老年DS患者术后残留轻度的矢状面失衡对生活质量影响不明显,LL=PI±9°可能不适合作为国人的矫形目标。     

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.     

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.     

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.