不同术后引流方式在腰椎融合手术中的应用比较

目的在后路腰椎融合手术中,对比持续负压引流和交替引流的疗效差异。方法自2016-03-2017-03共纳入70例后路腰椎融合手术患者,随机分为两组,其中对照组31例,术后留置常规持续负压引流(保持1/2个大气压);研究组39例采用交替引流:术后24 h内留置持续负压引流,24 h后则更换为常压引流直至拔除引流管。结果两组患者术后的引流管放置时间、术后卧床时间、VAS评分改善情况,以及术后24 h和7 d时的体温情况对比,差异均无统计学意义(P0.05);但研究组患者术后总引流量为(197.46±37.82)ml,显著少于对照组的(322.58±81.69)ml,组间差异有统计学意义(P0.05)。两组术后均未发生切口皮下血肿、感染、脑脊液漏等并发症,切口均顺利愈合。结论对后路腰椎融合手术切口予以"交替引流",可显著减少总引流量,且并未增加术后并发症,对患者康复进程亦无不良影响,其操作简单,有较好的临床应用价值。     

侧路经皮椎间孔镜技术在腰椎后路术后再次手术中的应用

目的:探讨侧路经皮椎间孔镜技术(transforaminal endoscopic spine system,TESSYS)在腰椎后路术后再次手术中的应用效果。方法:自2012年1月至2013年10月,根据纳入标准,筛选14例腰椎后路术后需要再次手术的患者,应用TESSYS治疗。其中男8例,女6例;年龄27～84岁,平均(50.4±18.9)岁。观察比较手术前后视觉疼痛模拟评分 (visual analogue scale,VAS)及日本骨科协会评分 (Japanese Orthopaedic Association Scores,JOA评分),并采用改良的Macnab标准评估疗效。结果:所有患者获得随访,时间6～27个月,平均18个月。术前及术后1周,3、6个月的VAS分别为6.79±1.31,2.50±1.29,2.21±1.53,1.64±1.08,术后与术前比较差异有统计学意义(P <0.01);JOA评分分别为12.43±1.95,21.50±3.78,21.93±4.55,23.36±4.33,术后较术前明显提高(P <0.01).按改良的Macnab 标准评定,优5例,良7例,可1例,差1例。1例穿刺过程中损伤L5神经根,其余患者无并发症。结论:选择合适的病例,在腰椎后路术后再次手术中应用TESSYS治疗,可以成功避开初次手术瘢痕,减少并发症,取得满意的临床效果。     

后路短节段固定结合潜行减压治疗上腰椎爆裂性骨折

目的:观察后路短节段固定结合保留后方韧带复合体(PLC) 的潜行减压治疗上腰椎爆裂性骨折的临床效果。方法:2010年10月至2013年3月采用后路短节段复位固定和保留PLC的潜行减压治疗上腰椎爆裂性骨折患者(Denis B型)23例,男18例,女5例;年龄26～64岁,平均45.7岁;高处坠落伤12例,车祸伤5例,重物砸伤4例,其他外伤2例;L1骨折14例,L2骨折9例;伴神经损害13例(ASIA评分D级).术后12～20个月(平均14.3个月)取出内固定。术后定期随访并比较各时间点神经功能JOA评分和影像学动态变化。结果:所有患者获得随访,时间18～24个月,平均20.4个月。13例伴神经损害者术后3～6个月神经症状均完全恢复。术后1年和去除内固定后3个月JOA评分分别为20.63±0.92和20.38±1.06,较术后3个月的9.90±2.73明显改善(P<0.05).术后1年伤椎前缘高度、伤椎楔变角、局部Cobb角分别为(95.1±0.53)%、(2.78±1.36)°、(2.43±1.52)°,均较术前明显改善(P<0.05).去除内固定3个月后与术后1年JOA评分及影像学结果比较差异无统计学意义(P>0.05) .结论:后路短节段复位固定结合保留PLC的潜行减压治疗上腰椎爆裂性骨折创伤小,能有效恢复椎体高度,维持脊柱稳定性,减轻术后腰背痛,是安全有效的手术方式。     

单一后路病灶清除植骨内固定加局部化疗治疗胸腰椎结核

目的:探讨单一后路病灶清除植骨内固定加局部化疗治疗胸腰椎结核的临床疗效。方法:自2009年2月至2012年9月,对胸腰椎结核11例患者行单一后路病灶清除植骨内固定加局部化疗治疗,男7例,女4例;年龄27～65岁,平均53.7岁;病程3个月～2年,平均9个月。脊髓损伤程度根据ASIA损伤分级:C级3例,D级8例。根据ASIA损伤分级评估神经功能恢复程度,依据疼痛视觉评分(VAS)、Oswestry功能障碍指数(ODI)评价临床症状改善情况,通过胸腰椎侧位X线片评估后凸Cobb角的变化。结果:11例均获随访,时间12～29个月,平均18个月。脊髓损伤ASIA损伤分级:3例C级患者中2例术后提高至D级,1例提高至E级;8例D级患者中7例提高至E级,1例无变化。VAS术前为6.10±1.30,术后3 d为1.70±0.80,较术前明显改善(P<0.05).Oswestry功能障碍指数术前为(68.36±10.41)%,术后3 d为(14.55±8.99)%,较术前明显改善(P<0.05).后凸Cobb角术前为(22.64±4.84)°,术后3 d为(4.27±1.49)°,较术前明显改善(P<0.05),末次随访时为(4.55±1.70)°,与术后3 d比较Cobb角差异无统计学意义(P>0.05).随访期间无复发病例。结论:单一后路病灶清除植骨内固定加局部化疗治疗胸腰椎结核具有切口单一、手术创伤小、有效清除病灶、改善神经功能、矫正畸形、复发率低的优点,但仍需结合长期、规范的全身抗结核药物治疗。     

等体温灌洗液在椎板间入路经皮椎间孔镜术中的应用研究

目的：探讨经椎板间入路椎间孔镜下腰椎髓核摘除术中两种温度灌洗液对患者体温、炎性细胞因子水平以及出血量的影响。方法：采用回顾性分析方法,选取2018年1月至2020年12月收治的行椎板间入路经皮椎间孔镜手术患者80例,根据术中灌洗液的温度分为试验组(40例)和对照组(40例)。其中试验组男19例,女21例;年龄(38.8±9.8)岁;L_4,5 7例,L₅S₁ 33例;身体质量指数(body mass index,BMI)(27.8±7.2) kg·m^-2;使用加温至37℃的生理盐水为灌洗液。对照组男18例,女22例;年龄(41.5±10.9)岁;L_4,5 5例,L₅S₁ 35例;BMI(26.4±6.2) kg·m^-2;使用室温20~22℃生理盐水作为灌洗液。从镜下操作开始后每间隔10 min记录患者体温,观察术中并发症;记录术前和术后2 h肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素-6(interleukin-6,IL-6)和白细胞介素-10(interleukin-10,IL-10)水平;采用视觉模拟评分法(visual analogue scale,VAS)评估两组患者术前和术后2 h腰部疼痛程度;记录两组患者术前和术后2 h纤溶-凝血指标,包括D-二聚体(D-dimer,DD)、纤维蛋白原降解产物(fibrinogen degradation products,FDP)、活化部分凝血活酶时间(activated partial thrombin time,APTT)和凝血酶原时间(prothrombin time,PT);记录两组患者手术时间和出血量。结果：所有患者术中体温呈下降趋势,对照组体温低于试验组。试验组共12例不良反应事件,对照组共22例不良反应事件,组间差异有统计学意义(P<0.05)。两组患者术后2 h血TNF-α,IL-6和IL-10水平均较术前升高(P<0.05),试验组升高水平均低于对照组(P<0.05)。试验组术后腰痛VAS小于对照组(P<0.05)。两组患者术后2 h D-dimer和FDP水平均较术前均升高(P<0.05),试验组低于对照组(P<0.05)。两组患者术后APTT与PT水平较术前差异无统计学意义(P>0.05)。出血量试验组(45.2±14.1) ml,对照组(59.5±15.6) ml,试验组少于对照组(P<0.05)。手术时间试验组(46.7±13.8) min,小于对照组的(58.3±15.2) min(P<0.05)。结论：较传统室温灌洗液,等体温灌洗液能减少椎间孔镜术中不良反应发生率,减轻局部炎症反应,减少术中出血量并缩短手术时间。     

动力髋螺钉加防旋螺钉与3枚空心螺钉治疗股骨颈粉碎性骨折的疗效比较

目的:比较3枚空心螺钉与动力髋螺钉(dynamic hip screw,DHS)加防旋螺钉治疗股骨颈粉碎性骨折的临床疗效.方法:自2008年1 月至 2012年12月,治疗股骨颈粉碎性骨折67例,根据不同内固定方式分为两组,其中36例采用DHS加防旋螺钉固定治疗(DHS组),男24例,女 12 例,年 龄22~58岁,平均43.7岁;31例采用3枚空心螺钉固定治疗(空心钉组),男22例,女9例,年 龄24~56岁,平均43.0岁.观察并比较两组患者切口大小、手术时间、术中出血量、输血率、术后住院时间、下地行走与患肢负重时间、骨折愈合时间、并发症发生率,采用髋关节Harris 评分对两组患者的功能进行比较.结果:两组患者术后切口均Ⅰ期愈合.两组手术时间、术中出血量、术中输血率及术后住院时间比较,差异无统计学意义(P>0.05).切口长度:DHS组(5.00±0.86) cm,空心钉组(3.30±0.57) cm,两组比较差异有统计学意义(P<0.01).所有患者获1年以上随访,两组随访时间差异无统计学意义(P>0.05).术后下地行走时间:DHS组为(19.0±3.5) d,空心钉组为(37.0±6.3) d,差异有统计学意义(P<0.01).患肢部分负重时间和完全负重时间:DHS组分别为术后(23.0±7.0) d、(138.0±13.0) d,空心钉组分别为术后(38.0±5.7) d、(164.0±12.0) d,差异均有统计学意义(P<0.01).骨折愈合时间:DHS组为(151±11) d,空心钉组为(162±11) d,差异有统计学意义(P<0.01).末次随访时髋关节Harris 评分:DHS组为(91.0±5.7)分;空心钉组为(85.0±12.0)分,差异有统计学意义(P<0.01).两组术后并发症比较,差异无统计学意义(P>0.05).结论:对于股骨颈粉碎性骨折的治疗,DHS 联合防旋螺钉优于3枚空心螺钉固定,具有术后患肢负重更早,骨折愈合更快,髋关节功能更好的优点.     

铜绿假单胞菌注射液治疗甲状腺乳头状癌颈侧区淋巴结清扫术后淋巴漏的临床观察

背景与目的 淋巴漏为颈部淋巴结清扫术后常见并发症,传统治疗方法作用相对有限,而铜绿假单胞菌注射液处理创面可较好促进局部炎症反应以闭合漏点,因此本研究分析铜绿假单胞菌注射液对甲状腺乳头状癌（PTC）颈侧区淋巴结清扫术后淋巴漏患者引流量的影响及安全性,以明确铜绿假单胞菌注射液的应用价值。方法 回顾性分析2019年1月—2020年1月郑州大学第一附属医院甲状腺外科行颈侧区淋巴结清扫术后出现淋巴漏的69例PTC患者资料,依据淋巴漏治疗方式不同将其分为对照组（37例,术中常规双侧留置负压引流）、观察组（32例,在对照组治疗的基础上,术后第4、6天,通过引流管注入2支铜绿假单胞菌注射液）,比较两组术后引流量、体温变化,记录其引流时间及不良反应发生率。结果 两组术后第1、2、3天引流量比较差异无统计学意义（均P>0.05）,观察组术后第4、5、6天引流量低于对照组［（310.79±32.16）mL vs.（338.64±34.55）mL、（157.82±16.43）mL vs.（325.43±33.96）mL、（87.34±8.59）mL vs.（333.68±34.59）mL,均P<0.05］;观察组术后第6、7 天体温高于对照组［（37.78±3.77）℃ vs.（35.96±3.60）℃、（37.65±3.72）℃ vs.（35.79±3.68）℃,均P<0.05］,其他时点两组体温差异均无统计学意义（均P>0.05）;观察组引流时间明显短于对照组［（6.17±0.63）d vs.（7.28±0.75）d,P<0.01］;观察组部分患者术后2周内出现局部发热、寒战不良反应,予以物理降温后均恢复正常,观察组术后不良反应发生率高与对照组（12.50% vs. 8.11%）,但差异无统计学意义（P>0.05）。结论 铜绿假单胞菌注射液治疗PTC患者颈侧区淋巴结清扫术后淋巴漏患者临床效果较好,可降低引流量,缩短引流时间,部分患者可能有体温升高、发热等现象,经对症处理后均可缓解,不影响治疗。     

两种入路脊柱内镜椎管减压治疗单节段腰椎侧隐窝狭窄症

目的: 探讨椎板间入路脊柱内镜腰椎管减压术(interlaminar percutaneous endoscopic lumbar decompression,IL-PELD)与椎间孔入路脊柱内镜腰椎管减压术(transforamenal percutaneous endoscopic lumbar decompression,TF-PELD)在单节段腰椎侧隐窝狭窄症的临床疗效。方法: 自2018年4月至2021年7月采用脊椎内镜椎管减压术治疗85例单节段腰椎侧隐窝患者,其中男44例,女41例,年龄49~81 (65.5±8.3)岁;病程3~83 (26.7±16.5)个月。根据手术方式不同,分为IL-PELD组和TF-PELD组。其中IL-PELD组47例,男28例,女19例;年龄50~80(66.7±9.3)岁;病程3~65(25.7±15.0)个月。TF-PELD组38例,男16例,女22例;年龄51~78(64.1±7.6)岁;病程4~73(27.9±18.3)个月。记录两组手术时间、出血量、术中透视次数、住院时间及并发症等情况。于术前和术后1、6个月及末次随访时以疼痛视觉模拟评分(visual analogue scale,VAS)评估腰痛及下肢痛的程度、以Oswestry功能障碍指数(Oswestry disfunction index,ODI)评估腰椎功能。末次随访时以改良Macnab标准评估临床疗效。于术前和术后1周以侧隐窝矢状径评估责任椎间隙侧隐窝的减压程度。结果: 两组均顺利完善手术,无血管损伤、硬膜囊撕裂、神经损伤等严重并发症。所有病例获得1年以上随访,时间14~53(27.0±9.4)个月。术后切口均Ⅰ期愈合,未发生椎间隙感染。IL-PELD组手术时间(69.3±19.3) min,多于TF-PELD组(57.5±14.5) min (P<0.05)。两组术中出血量比较差异无统计学意义 (P>0.05)。TF-PELD组术中透视次数(8.8±2.6)次,多于IL-PELD组(4.8±1.2)次(P<0.05)。两组住院日比较差异无统计学意义(P>0.05)。IL-PELD组术前腰痛、下肢痛VAS及ODI分别为(5.1±2.2)、(6.9±1.3)分、(71.4±12.6) %,TF-PELD组分别为(4.7±1.8)、(6.9±1.3)分、(68.4±13.9) %。IL-PELD组术后1、6个月及末次随访腰痛VAS为(2.4±1.5)、(1.6±0.8)、(1.4±0.9)分,下肢痛VAS为(3.0±1.2)、(1.6±0.7)、(1.5±1.0)分,ODI 为(32.6±11.9) %、(17.4±6.5) %、(19.3±9.3) %;TF-PELD组术后1、6个月及末次随访腰痛VAS为(2.6±1.4)、(1.5±0.6)、(1.4±1.0)分,下肢痛VAS为(2.8±1.2)、(1.6±0.6)、(1.5±1.2)分,ODI为(32.0±11.2) %、(15.0±6.1) %、(20.0±11.3) %。两组术后各时间点腰痛VAS、下肢痛VAS及ODI较术前明显改善(P<0.05),组间差异均无统计学意义(P>0.05),不同时间点-分组交互作用差异均无统计学意义(P>0.05)。术后1周时两组侧隐窝矢状径均较术前显著增加(P<0.05),但各时间点两组侧隐窝矢状径组间差异无统计学意义(P>0.05)。末次随访时两组改良 Macnab标准比较,差异无统计学意义(P>0.05)。结论: IL-PELD和TF-PELD治疗单节段腰椎侧隐窝狭窄症均能扩大侧隐窝,并取得良好早期临床疗效。     

关节镜双后内入路与切开手术治疗急性单纯后交叉韧带胫骨止点撕脱骨折早期疗效对比

目的:比较关节镜双后内入路与切开手术治疗急性单纯后交叉韧带胫骨止点撕脱骨折的疗效差异。方法:回顾性分析2016年6月至2020年6月经手术治疗的52例急性单纯性后交叉韧带胫骨止点撕脱骨折患者的临床资料,按手术方案不同分为两组,关节镜组27例患者行关节镜双后内入路手术治疗,其中男16例,女11例,年龄19~52(34.9±9.2)岁;切开复位组25例患者行膝关节后内侧切口手术治疗,其中男14例,女11例,年龄18~54(33.7±8.4)岁。观察并比较两组患者手术时间、切口长度、术中出血量、住院时间、住院费用、术后愈合情况、并发症以及术后12个月Lysholm、IKDC评分。结果:两组患者均顺利完成手术,无血管、神经损伤。52例均获得随访,时间6~24(15.0±1.7)个月。关节镜组手术时间、住院费用大于切开复位组(P<0.05);关节镜组术中出血量、切口长度、住院时间小于切开复位组(P<0.05);关节镜组和切开复位组术后12个月Lysholm评分分别为(95.9±1.7)分和(86.4±1.2)分,均较术前的(49.1±2.3)分和(48.9±1.1)分显著提高(P<0.05);关节镜组和切开复位组术后12个月IKDC总分分别为(96.9±1.5)分和(87.1±1.4)分,均较术前的(47.6±4.1)分和(48.1±3.9)分显著提高(P<0.05);关节镜组术后12个月膝关节Lysholm、IKDC评分均高于切开复位组(P<0.05)。结论:关节镜双后内入路治疗急性单纯后交叉韧带胫骨止点撕脱骨折,早期效果满意,疗效优于传统开放手术,具有创伤小、恢复快、操作简便等优点。     

直接上方入路与后外侧入路在高龄股骨颈骨折半髋置换术中的早期疗效比较

目的:对比分析直接上方入路(direct superior approach,DSA)与后外侧入路(posterior lateral approach,PLA)在高龄股骨颈骨折半髋置换术中的早期临床疗效。方法:回顾性分析2020年1月至 2021 年12月收治的72例接受半髋置换手术老年股骨颈骨折患者的临床资料,其中36例采用微创DSA入路,男10例,女26例,年龄(82.82±4.05)岁;36例采用传统PLA入路,男14例,女22例,年龄(82.79±3.21)岁。比较两组患者围手术期相关指标、不同时间点Harris评分。结果:DSA组手术时间(79.41±17.39) min,比PLA组(98.45±26.58) min更短;切口长度(8.33±2.69) cm,比PLA组(11.18±1.33) cm短;术中失血量(138.46±71.58) ml,比PLA组(173.51±87.17) ml更少;初次下地时间(3.04±0.95) d,比PLA组(4.52±1.10) d更早;住院时长(8.70±1.89) d,比PLA组(10.67±2.35) d短(P<0.05)。两组术前Harris评分差异无统计学意义(P>0.05),术后1个月DSA组Harris功能和总分高于PLA组(P<0.05),而术后12个月两组比较,差异无统计学意义(P>0.05)。结论:在半髋置换手术中,DSA入路较PLA入路在手术时间、术中出血量、切口长度、初次下地时间、住院时长以及术后1个月的Harris评分等临床指标更优,在促进高龄股骨颈骨折患者术后早期康复上具有明显优势。     

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.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.