两种颈后路单开门手术方法对颈椎曲度指数及活动度的影响

[目的]探讨两种颈后路单开门手术方法对术后患者神经功能改善率、颈椎曲度指数、颈椎活动度的影响及其临床意义.[方法]自2008年6月～2011年9月,78例脊髓型颈椎病患者接受颈后路单开门椎管扩大成形术.A组41例患者行改良术式,即保留颈半棘肌肌止,切除C3椎板,C4-7“锚定法”单开门椎管扩大成形术.B组37例患者行传统C3-7单开门椎管成形术.计算两组患者神经功能改善率及术前术后颈椎曲度指数、颈椎活动度的变化,研究两组间差异.[结果]两组患者术后神经功能改善恢复率,A组为(57.5±19.4)％,B组为56.3±19.8％,两组间差异无统计学意义,术后颈椎曲度指数丢失百分比,A组丢失(2.86±2.44)％,B组丢失(5.31±2.12)％,B患者手术前后颈椎曲度指数丢失明显多于A组.术后颈椎活动度,A组患者术后丢失(8.27±5.03).,B组患者术后丢失(11.06±6.97)°,两组差异有统计学意义(P＜0.01).[结论]保留颈半棘肌肌止,C3椎板切除,C4-7“锚定法”单开门椎管扩大椎管成形术,与传统术式相比具有同样的神经功能改善率,同时能有效防止颈椎曲度指数及颈椎活动度的丢失.     

C3椎板切除并保留C7棘突的颈椎管扩大双开门成形术

[目的] 对传统C3～7椎板成形术进行改良,观察改良手术疗效,探讨其能否有效降低并发症的发生.[方法] 改良椎板成形术治疗脊髓型颈椎病20例(A组),A组患者平均年龄65.7岁(45～83岁);男14例,女6例;平均随访时间为18个月(12～27个月).传统术式对照组(B组)为本院同期行传统C3～7椎板成形术的18例患者,B组患者平均年龄59岁(46～75岁);男11例,女7例;平均随访时间为25 个月(12～50个月).对两组患者手术前后的JOA评分、颈椎曲度角度、颈椎活动度及轴性症状严重程度进行比较评估.[结果] JOA评分恢复率,A组患者为46.5%,B组患者为54.1%,两组差异无统计学意义( P>0.05).A组术后有明显轴性症状患者的比例为10%,B组为44.4%,两组比较差异有统计学意义(P<0.05).A组患者术后颈椎曲度Cobb's角11.2°±9.2°,B组患者术后颈椎曲度Cobb's角10.9°±10.1°,A组和B组患者手术前后颈椎曲度的变化差异无统计学意义(P>0.05).A组患者术后颈椎活动度丢失6.9°±4.0°,B组患者术后颈椎活动度丢失11.6°±7.8°,两组差异有统计学意义(P<0.01).[结论] C3椎板切除保留C2棘突半棘肌附着、同时保留C7棘突颈背肌肉附着的颈椎管扩大椎板成形术能获得良好神经减压效果,同时可以最大程度维持颈半棘肌和颈背肌结构和功能的完整性,减少对颈椎后伸机制和颈椎稳定机制的破坏,从而保留颈椎的活动度和降低术后颈椎轴性症状的发生.     

保留颈半棘肌的颈椎后路双开门椎管扩大成形术的疗效研究

目的探讨保留颈半棘肌的颈椎后路双开门椎管扩大成形术的临床疗效.方法回顾性分析2001年2月至2009年7月行后路双开门颈椎椎管扩大成形术的189例患者的临床资料,根据术中是否切断C2棘突半棘肌将患者分为颈半棘肌切断组(C3~C7椎板成形术,102例)和颈半棘肌未切断组(C3椎板切除、C4~C7椎板成形术,87例).采用日本骨科协会(JOA)评分法进行神经功能评价;AS程度采用视觉模拟评分法(VAS)进行评价.结果两组手术时间、颈椎曲度、颈椎活动度、颈托固定时间比较,差异有统计学意义(P<0.05).两组术后6个月JOA评分均较术前有明显升高(P<0.05),但两组间比较,差异无统计学意义(P>0.05).术后轴性症状(AS)总发生率为30.2%(57/189),其中颈半棘肌切断组37例(19.6%)、颈半棘肌未切断组20例(10.6%),两组比较,差异有统计学意义(P<0.05).两组末次随访VAS均较术前明显下降(P<0.05);两组间比较,差异有统计学意义(P<0.05).结论颈椎后路双开门椎管扩大成形术可有效改善神经功能,但保留颈半棘肌的手术方式缩短了手术时间,保持了颈椎曲度和活动度,有助于减少术后AS的发生.     

颈椎后路改良单开门椎管扩大成形术治疗多节段脊髓型颈椎病的疗效分析

目的 :探讨颈椎后路改良单开门椎管扩大成形术治疗多节段脊髓型颈椎病的临床效果。方法 :回顾性分析2013年6月~2015年12月采颈椎后路单开门椎管扩大成形术治疗并获得随访的多节段脊髓型颈椎病患者,均采用相同的微型钛板固定单开门椎板,其中21例(男17例,女4例,年龄66.2±10.0岁)采用改良单开门椎管扩大成形术(改良组),39例(男36例,女3例,年龄57.3±10.5岁)采用传统单开门椎管扩大成形术(传统组),收集两组患者手术时间、术中出血量、术后住院时间、手术费用,随访两组患者神经功能改善情况、颈椎曲度、颈椎曲度指数、颈椎活动度及轴性症状等,并进行比较。结果:两组患者性别、年龄、病程、手术时间、术中出血量、术后住院时间均无显著性差异(P0.05),两组手术费用比较有显著性差异,改良组平均手术费用明显低于传统组(P0.05)。术后随访12~24个月,术后12个月两组患者均达到骨性融合,两组神经功能均明显改善,JOA评分改善率改良组为(60.46±9.65)%,传统组为(46.41±24.33)%,两组比较无显著性差异(P0.05)。改良组术后12个月时颈椎曲度丢失4.7°±1.9°,颈椎曲度指数丢失(3.09±.14)%,颈椎活动度丢失7.3°±2.3°;传统组颈椎曲度丢失8.9°±5.6°,颈椎曲度指数丢失(6.27±3.42)%,颈椎活动度丢失13.0°±3.9°,两组比较均有显著性差异(P0.01)。改良组术后出现轴性疼痛症状患者3例,传统组为19例,两组比较有显著性差异(P0.01)。随访期间两组均无再关门发生,两组均无钛板、螺钉松动移位。结论:与颈椎后路传统单开门椎管扩大成形术相比,改良单开门椎管扩大成形术在获得良好神经减压效果的同时,可减少手术费用,降低术后颈椎轴性症状的发生率,有利于颈椎曲度和颈椎活动度的维持。     

颈椎硬膜内髓外肿瘤手术治疗方式选择

目的 探讨颈椎硬膜内髓外肿瘤的手术方式及钛网椎管重建的效果.方法 2002年3月至2008年9月手术治疗颈椎硬膜内髓外肿瘤26例,男14例,女12例;年龄6～76岁,平均38岁.术前神经功能Frankle分级,B级3例,C级8例,D级11例,E级4例.16例行半椎板切除(半椎板组),10例全椎板切除后行钛网椎管重建(全椎板组).术后随访6个月～5年,平均26个月,记录术后神经恢复及植骨融合情况.确认植骨融合后(术后6个月),对半椎板组和全椎板组病例手术前后的颈椎曲度指数、颈椎活动度进行评估.结果 术后神经功能恢复Frankle分级均有改善.术前Frankle分级B级3例,术后提高到C级;术前C级8例提高到D级;术前D级11例提高到术后E级10例、D级1例.全椎板组钛网表面植骨块与上、下椎板融合,术后脊柱稳定,未发生畸形.半椎板组术后颈椎曲度指数丢失2.2±2.3,全椎板组术后颈椎曲度指数丢失4.3±2.5,两组患者手术前后颈椎曲度变化的差异有统计学意义(t=2.05,P＜0.05).半椎板组术后颈椎活动度丢失1.3°±1.2°,全椎板组患者术后颈椎活动度丢失9.2°±4.1°,两组差异有统计学意义(t=1.71,P＜0.05).结论 颈椎硬膜内髓外肿瘤体积小位于椎管一侧,适宜选择半椎板切除.对于需要行全椎板切除的病例,内固定及钛网椎管重建加植骨,可以重建脊柱的稳定性.     

改良单开门椎管扩大成形术治疗脊髓型颈椎病

目的探讨改良单开门椎管扩大成形术治疗脊髓型颈椎病的疗效。方法2005年3月至2006年5月,18例脊髓型颈椎病患者接受改良单开门椎管扩大成形术,即受压节段两端行部分椎板切除,中央行单开门椎管扩大成形术（A组）,23例患者接受传统C3-7,单开门椎板成形术,作为对照组（B组）,对两组患者手术前后的JOA评分改善率、减压程度、颈椎曲度指数、颈椎活动度及轴性症状严重程度进行随访,并比较评估。结果41例全部获得随访,JOA评分恢复率A组为（62．0±26．4）％,B组为（62．7±19．8）％,两组差异无统计学意义;两组病例术后MRI均显示椎管减压充分．患者术后颈椎曲度指数丢失A组为（2．75±2．68）％,B组为（5．23±2．02）％,两组比较差异有统计学意义（P〈0．01）;术后颈椎活动度丢失A组为（7．21±4．07）°,B组为（13．16±6．34）。,两组差异有统计学意义（P〈0．01）;术后有明显轴性症状者A组为22．2％．B组为56．5％．两组比较差异有统计学意义（P〈0．05）。结论改良椎管扩大成形术获得了良好的神经减压效果,与传统C3-7单开门椎板成形术相比,在对颈椎曲度指数、颈椎活动度的影响以及轴性症状发生率等方面有明显改善。     

保留颈后方韧带复合体重建伸肌附着点单开门椎板成形术治疗颈椎疾患的临床观察

目的观察保留颈后方韧带复合体、重建颈伸肌群附着点单开门颈椎板成形术治疗颈椎疾患的临床疗效.方法2000年8月～2004年10月应用保留颈后方韧带复合体、重建颈伸肌群附着点单开门颈椎板成形术治疗颈椎疾患34例,其中男20例,女14例,年龄53～68岁,平均58.5岁.脊髓型颈椎病(CSM)18例,后纵韧带骨化症(OPLL)9例,无骨折脱位型颈脊髓损伤7例.比较患者手术前后JOA评分、颈椎生理曲度(C2～C7角)、活动范围(ROM).结果术前JOA评分平均8.6分,中立位C2～C7角平均8.6.,ROM平均43.5°.术后平均随访2.5年,末次随访时JOA评分平均12.5分,与手术前比较有显著性差异(P＜0.05),改善率46-4%;中立位C2～C7角平均9.4°.与手术前比较无显著性差异(P＞0.05);ROM平均33.8°,与手术前比较有显著性差异(P＜0.05).结论保留颈后方韧带复合体-重建颈伸肌群附着点单开门颈椎板成形术术后可有效维持颈椎生理曲度.     

选择性融合联合单开门椎管扩大椎板成形术治疗局部不稳的颈椎后纵韧带骨化症的疗效

目的:比较三种颈椎后路术式治疗存在局部不稳的颈椎后纵韧带骨化症(ossification of the posterior longitudinal ligament,OPLL)患者的临床疗效,探讨选择性融合联合单开门椎管扩大椎板成形术的临床应用价值。方法:回顾分析我院2014年6月~2017年6月收治的存在局部不稳的颈椎OPLL患者107例,其中男性61例,女性46例;年龄68.1±10.2岁(33~84岁),随访时间2.1±1.3年(0.5~3.5年)。所有患者证实存在OPLL及颈椎局部不稳,且存在颈脊髓压迫相关症状体征,其中38例行单纯颈后路单开门椎管扩大椎板成形术(A组),35例行选择性融合联合单开门椎管扩大椎板成形术(B组),34例行传统颈后路椎板切除固定术式(C组)。分别于术前、术后2d及末次随访时采用日本矫形外科学会(Japanese Orthopaedic Association,JOA)评分并计算Hirabayashi改善率,对患者的神经功能情况进行评估;拍摄颈椎正侧位及过屈过伸位X线片测量颈椎的曲度(C2-7 Cobb角)、颈椎整体活动度(C2-7 range of motion,C2-7 ROM)和颈椎不稳节段的活动度,统计内固定相关并发症。通过颈椎MRI评估患者颈髓高信号的情况并计算高信号强度比值(high signal intensity ratio,HSIR)。比较三组患者颈椎整体活动度和不稳节段的活动度,比较存在颈髓高信号患者的术前、术后HSIR及三组之间的差异。结果:三组患者均取得了满意的神经功能改善,末次随访时JOA评分分别为14.93±3.18分、15.22±2.79分和14.72±3.02分,Hirabayashi改善率分别为(66.35±13.48)%、(70.06±14.14)%和(64.14±18.05)%。三组患者术前颈椎曲度分别为7.43°±3.69°、7.66°±2.99°、6.96°±4.38°,组间比较无统计学差异(F=13.19,P=0.071),末次随访时颈椎曲度与术前相比基本一致(5.58°±4.26°、5.73°±3.81°、5.49°±4.33°),随访期间未发现颈椎曲度明显改变、后凸等情况。随访期间未出现内固定相关并发症。末次随访时A、B两组患者颈椎整体活动度(C2-7 ROM)无统计学差异(17.63°±8.31°和18.72°±9.52°,P=0.089),C组患者末次随访颈椎整体活动度明显差于A、B两组患者(3.90°±7.74°vs 17.6°±8.3°,P=0.012;3.90°±7.74°和18.72°±9.52°,P=0.003);B组、C组患者术后颈椎不稳节段活动度明显降低,末次随访时已完全融合。共有71例(71.03%)患者出现颈椎MRI T2加权高信号表现,存在高信号的节段与存在不稳的节段一致。三组患者HSIR值末次随访时均较术前明显降低(1.33±0.18 vs 1.68±0.11,1.12±0.12 vs 1.71±0.14和1.20±0.33 vs 1.65±0.18,P=0.001),但与A组患者相比,B组和C组患者的降低程度均较显著,差异存在统计学意义(P<0.05)。结论:选择性融合联合单开门椎管扩大椎板成形术是治疗存在局部不稳的颈椎OPLL患者的有效方法,可以在广泛减压颈脊髓压迫的同时增加颈椎的节段稳定性,同时保留颈椎一定的活动度、减少术后轴性症状发生。     

颈椎后路单开门椎管减压Centerpiece钛板内固定治疗多节段脊髓型颈椎病的早期疗效分析

目的探讨颈椎后路单开门椎管减压Centerpiece钛板内固定治疗多节段脊髓型颈椎病的早期临床疗效。方法回顾性分析自2010-08—2014-03行颈椎后路单开门椎管减压Centerpiece钛板内固定治疗的27例多节段脊髓型颈椎病。结果本组平均随访13.7个月。末次随访时JOA评分为(14.6±2.4)分,神经功能改善率(73.0±7.6)%。术后3 d复查颈椎MRI提示颈椎椎管明显扩大,颈髓压迫解除;颈椎三维CT检查未见单开门椎板塌陷以及椎板"再关门"颈髓受压的发生。铰链侧骨折缝隙消失时间为(5.7±1.2)个月,27例均达到骨性融合。术后3 d及术后6个月C5椎管矢状径无变化,均为(16.3±1.1)mm,椎管扩大率为(73.4±10.2)%。结论颈椎后路单开门椎管减压Centerpiece钛板内固定治疗多节段脊髓型颈椎病具有稳定的力学特点,可提供较稳定的固定,早期疗效满意。     

颈椎单开门椎管扩大成形术椎板开门角度对脊髓型颈椎病疗效的影响

目的:探讨椎板开门角度对颈椎单开门椎管扩大成形术(expansion of open-door laminoplasty)治疗脊髓型颈椎病疗效的影响。方法:选取我院2006年7月至2009年1月采用颈椎后路单开门椎管扩大成形术治疗并获得24个月以上随访的脊髓型颈椎病患者198例,男115例,女83例;年龄29～72岁,平均49±5岁。双节段39例(C3～C5 11例,C4～C6 28例);三个节段(C4～C7)97例,四个节段(C3～C7)62例。患者均有术前颈椎正侧位、双斜位和过度屈伸位X线平片和颈椎CT及MRI检查图片;术前JOA评分4～9分,平均6.3±2.9分。按照术后1周CT片上测量的椎板开门角度以30°为界限分为两组,统计两组手术时间、出血量、术后出现并发症病例、C2-C7 Cobb角度、颈椎前凸指数、颈椎活动度和脊髓后移数值,末次随访时评价患者神经功能情况,计算神经功能改善率。结果:开门角度>30°的患者共76例(A组);开门角度15°～30°的患者共122例(B组)。两组术前JOA评分、C2-C7 Cobb角度、颈椎前凸指数及颈椎活动度无显著性差异(P>0.05)。A组手术时间110±13min,出血量250±80ml;B组手术时间120±30min,出血量230±100ml,两组比较均无显著性差异(P>0.05)。术后A组51例(67.1%)出现轴性症状,8例(10.4%)发生C5神经根麻痹,1例(1.32%)颈椎轻度后凸畸形;B组37例(10.5%)出现轴性症状,3例(2.4%)发生C5神经根麻痹,4例(3.28%)发生关门,A组轴性症状和C5神经根麻痹的发生率高于B组,差异有显著性(P<0.05)。术后1个月脊髓后移值为0～7.95mm,平均2.41±0.46mm。末次随访时两组C2-C7 Cobb角度、颈椎前凸指数及颈椎活动度无显著性差异(P>0.05);JOA评分改善率A、B组分别为(72.1±11.7)%和(69.0±12.3)%,两组间比较无显著性差异(P>0.05)。结论:不同椎板开门角度术后神经功能改善率无显著性差异;将椎板开门角度控制在15°～30°轴性症状及C5神经根麻痹发生率较低,但应防止发生关门。     

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.