颈椎前路减压融合术后钛笼下沉临床分析

目的:探讨颈椎前路减压融合术治疗脊髓型颈椎病术后影响钛笼下沉的相关因素。方法:回顾性分析2005年6月～2009年6月我院收治的104例行颈椎融合钛笼植骨患者的颈椎平片和手术资料,分析撑开程度、钛笼直径和安放部位与钛笼下沉的相关性。结果:104例手术患者中,术后6个月复查时发现16例(15.4%)钛笼发生下沉。46例钛笼直径10mm者中9例发生下沉(19.6%),而58例直径12mm者中7例发生下沉(12.1%),差异有显著性(P<0.05)。钛笼前缘与椎体前缘距离在1mm以内者89例,距离大于1mm者15例,发生下沉例数分别为13例和3例,差异有显著性(P<0.05)。开槽节段相邻椎体终板延长线成角,其中角度在20°～30°者82例,成角大于30°者22例,两组发生下沉例数分别为11例和5例,发生率有显著性差异(P<0.05)。结论:椎间撑开程度、钛笼直径和安放部位可能是影响钛笼下沉的重要因素。     

双节段颈椎前路椎体次全切除融合术后钛笼下沉的影响因素分析

目的 探讨双节段颈椎前路椎体次全切除融合术(anterior cervical corpectomy and fusion,ACCF)后钛笼(titanium mesh cage,TMC)下沉的影响因素.方法 回顾性分析我院2011年1月至2013年4月收治的86例应用TMC内固定行ACCF患者的颈椎正侧位片及临床资料,随访6个月,根据TMC下沉与否分为下沉组和非下沉组,分析术后TMC下沉与年龄、性别、手术节段、临床疗效、病变节段撑开角度及安置位置的相关性.结果 术后6个月,86例患者中有22例发生TMC下沉(25.6％),下沉组和非下沉组的年龄、性别、手术节段(C5～G)、骨密度、身体质量指数(BMI)之间差异有统计学意义(P＜0.05);两组术后日本骨科协会评分(Japanese Orthopedic Association Scores,JOA)均较术前明显改善,且非下沉组高于下沉组,差异有统计学意义(P＜0.05),但两组融合率的差异无统计学意义(P＞0.05);椎间撑开角度＜30°与≥30°,对下沉发生率的影响不同,差异有统计学意义(P＜0.05);椎体前缘与钛笼前缘间距＜1 mm与≥1 mm,对下沉发生率的影响不同,差异有统计学意义(P＜0.05).结论 椎间撑开角度和安放位置可能是影响TMC术后下沉的重要因素,此外年龄、性别、手术节段(C5～C7)、骨密度、BMI对TMC下沉均有不同程度的影响.     

颈椎ACCF术后出现钛笼下沉的危险因素Logistic回归分析

目的进行脊髓型颈椎病颈椎体次全切除融合术(anterior cervical corpectomy and fusion,ACCF)术后出现钛笼下沉的危险因素Logistic回归分析,为其预后的改善提供理论依据。方法纳入2014年6月～2017年6于我院行ACCF术治疗的102例脊髓型颈椎病患者,随访6个月,将钛笼下沉者设为下沉组,其余设为未下沉组。调查两组患者性别、影像检查等病历资料,采用单因素、多因素分析确定颈椎ACCF术后出现钛笼下沉的独立危险因素。结果术后20例发生钛笼下沉,下沉率19.61%;两组钛笼直径、椎体撑开程度、钛笼倾斜角、钛笼前缘与临近椎体前缘距离、钉板夹角差异具有统计学意义(P0.05);多因素分析钛笼直径(OR=2.321)、椎体撑开程度(OR=1.897)、钛笼倾斜角(OR=2.043)、钛笼前缘与临近椎体前缘距离(OR=2.248)是颈椎ACCF术后出现钛笼下沉的独立危险因素。结论脊髓型颈椎病患者ACCF术后钛笼下沉发生率较高,钛笼直径、椎体撑开程度、钛笼倾斜角、钛笼前缘与临近椎体前缘距离等均会增加钛笼下沉风险。     

单节段颈椎椎体次全切除钛笼植骨融合术后钛笼下沉相关危险因素分析

目的 :分析单节段应用钛笼植骨的颈椎椎体次全切除融合术(anterior cervical corpectomy and fusion,ACCF)术后钛笼下沉的相关危险因素。方法:统计并回顾性分析我院2014年7月~2016年6月间应用钛笼植骨的单节段ACCF的44例患者临床资料,测量术前、术后3d内和术后3个月复查时所拍摄的颈椎X线平片,根据术后3个月随访时融合节段高度与术后3d内融合节段相比高度变化,将患者分为下沉组(高度丢失2mm)与未下沉组(高度丢失≤2mm),测量并分析两组间撑开角、钛笼倾斜角、钛笼深度、钉板夹角之间是否存在统计学差异,并通过Logistic回归分析分析钛笼下沉的危险因素。结果:术后3个月随访时,17例(38.64%)患者纳入未下沉组(高度丢失≤2mm),27例(61.36%)患者纳入下沉组(高度丢失2mm)。下沉组与未下沉组之间钛笼倾斜角、钛笼深度、钉板夹角差异有统计学意义(P0.05),撑开角差异无统计学意义(P0.05)。多因素Logistic回归分析结果提示,钛笼倾斜角增加是钛笼下沉的危险因素[95%置信区间(1.065,1.374),P0.05]。结论:钛笼下沉为ACCF术后常见的现象。钛笼倾斜角为钛笼下沉的独立危险因素,若该角度8.6°将增加钛笼下沉的风险。     

颈椎前路椎体次全切除术后钛网下沉的原因分析及其对疗效的影响

目的探讨颈椎前路椎体次全切除术后出现钛网下沉的主要原因,以及钛网下沉对手术疗效是否有所影响。方法随机选择了2013-09-2015-09行颈椎前路椎体次全切除术的51例患者,术后均获得1年以上随访,其中17例术后出现钛网下沉。依据患者术后是否出现钛网下沉,将其分为两组:下沉组和未下沉组。对两组患者的术后JOA评分(17分制)改善率进行组间对比,同时统计其性别、年龄、手术节段分布、椎体撑开角度等相关指标,进行组间单因素分析和多因素Logistic回归分析。结果:单因素分析提示,年龄、手术节段及椎体撑开角度均与术后钛网下沉的发生有明显相关性(P0.05);多因素Logistic回归分析提示,年龄、手术节段、椎体撑开角度均为独立的危险因素。末次随访时,下沉组术后JOA评分改善率仅为(54.8±6.1)%,显著低于未下沉组的(67.2±4.3)%,差异有统计学意义(P0.05)。结论:颈椎前路椎体次全切除术后出现钛网下沉现象受诸多因素影响,其中,年龄偏高、手术节段多、椎间撑开角度过大,均是独立的危险因素;同时,钛网下沉对术后神经功能改善有一定的不良影响,应引起临床重视。     

3D打印人工椎体与钛笼在颈椎前路椎体次全切除减压植骨融合术中应用的效果比较

【摘要】目的：评估3D打印人工椎体与传统钛笼在颈椎前路椎体次全切除减压植骨融合术（anterior cervical corpectomy and fusion,ACCF）中应用的临床效果。方法：回顾性分析2017年6月～2020年6月于承德医学院附属医院脊柱外科行单椎体ACCF的50例脊髓型颈椎病患者,其中25例术中应用3D打印人工椎体（观察组）,25例术中应用传统钛笼植骨（对照组）。记录两组患者手术时间、术中出血量、C型臂X线机透视次数及随访时间。术前、术后3天、术后3个月及末次随访时在颈椎侧位X线片上测量椎体次全切除节段椎间高度（H1、H2）、C2-7 Cobb角、C2-7矢状面轴向距离（C2-7 sagittal vertical axis,C2-7 SVA）及T1倾斜角,比较两组患者各时间点的影像学参数;应用日本骨科协会（Japanese Orthopaedic Association,JOA）评分评价神经功能,应用疼痛视觉模拟（visual analogue scale,VAS）评分评价颈部疼痛。根据Kandziora标准判断植骨融合情况。结果：所有患者均获得随访,观察组随访时间12~33个月（24.16±4.95个月）;对照组随访时间12~33个月（22.60±5.91个月）,两组患者随访时间比较无统计学差异（P>0.05）。两组患者手术时间、术中出血量和C型臂X线机透视次数均无显著性差异（P>0.05）;两组患者术后各时间点的JOA评分和VAS评分较术前均有明显改善,差异均有统计学意义（P<0.05）,两组间同时间点比较无统计学差异（P>0.05）;术后两组患者各时间点的椎体间高度、C2-7 Cobb角、C2-7 SVA及T1倾斜角与术前相比均有明显改善（P<0.05）,两组间术前及术后3天比较无显著性差异（P>0.05）,术后3个月及末次随访时两组间比较有统计学差异（P<0.05）。末次随访时观察组19例人工椎体存在下沉,下沉距离为0.1~0.9mm,无严重下沉患者;对照组20例钛笼下沉,下沉距离为1.3~3.5mm,有4例严重下沉患者;观察组人工椎体下沉距离小于对照组钛笼下沉距离,差异有统计学意义（P<0.05）。末次随访所有患者均实现骨性融合。结论：脊髓型颈椎病患者行ACCF时应用3D打印人工椎体和传统钛笼植骨均可恢复椎体间高度,重建颈椎稳定性及颈椎生理曲度;3D打印人工椎体能够减缓术后支撑假体的沉降,进而维持减压椎体间高度。     

3D打印解剖型钛笼与传统钛笼在ACCF术中应用的比较研究

目的评估3D打印解剖型钛笼在单节段颈椎前路椎体次全切除植骨融合(ACCF)术中应用效果及其安全性。方法回顾性分析自2014-06—2015-12行C5椎体ACCF的56例脊髓型颈椎病,27例ACCF术中应用3D打印解剖型钛笼(观察组),29例ACCF术中应用传统钛笼(对照组)。比较2组手术时间、术中出血量、JOA评分改善率。术后3 d及末次随访于颈椎正侧位X线片上观察钛笼下沉距离、骨融合及融合节段Cobb角。结果 56例均获得随访,观察组随访时间(15.34±3.61)个月,对照组随访时间(15.42±2.98)个月。所有患者均达到骨性融合,融合率100%。观察组21例钛笼下沉,下沉0.3~0.7(0.52±0.21)mm,无严重下沉患者;对照组25例钛笼下沉,下沉2.3~4.2(2.93±0.42)mm,3例严重下沉;观察组钛笼下沉距离小于对照组,差异有统计学意义(P0.05)。观察组末次随访时JOA评分改善率为69.5%,对照组为67.0%,2组差异无统计学意义(P0.05)。观察组融合节段Cobb角小于对照组,差异有统计学意义(P0.05)。结论 3D打印解剖型钛笼在ACCF治疗单节段脊髓型颈椎病术中应用能够获得与传统钛笼相似的临床效果及骨性融合率,并且可以有效减少钛笼下沉现象,使用安全。     

颈前路椎管减压植骨融合内固定术中应用钛笼与n-HA/PA66人工椎体的疗效比较

目的比较颈椎病颈前路椎管减压植骨融合内固定术中置入钛笼与置入纳米羟基磷灰石/聚酰胺66(nanohydroxyapatite/polyamide66,n-HA/PA66)人工椎体的疗效。方法回顾性分析自2012-01—2017-02采用颈前路椎管减压植骨融合内固定术治疗的97例颈椎病,50例在术中置入钛笼(钛笼组),47例在术中置入n-HA/PA66人工椎体(人工椎体组),比较2组术后即刻、术后3个月、术后6个月颈椎前凸角度与JOA评分,比较2组术后椎体下沉情况以及末次随访时神经功能改善等级。结果97例均顺利完成手术并获得完整随访,随访时间平均10.4(6~18)个月。末次随访时97例均获得骨性融合。2组术后即刻、术后3个月、术后6个月颈椎前凸角度、JOA评分比较差异无统计学意义(P>0.05)。术后6个月钛笼组6例出现钛笼下沉现象,人工椎体组未出现人工椎体下沉现象。人工椎体组椎体下沉情况较钛笼组优,差异有统计学意义(P<0.05)。2组末次随访时神经功能改善等级比较差异无统计学意义(P>0.05)。结论钛笼与n-HA/PA66人工椎体均能有效重建颈椎的稳定性、改善脊髓功能并获得良好的植骨融合率,n-HA/PA66人工椎体置入后可以获得较低的椎体下沉率。     

零切迹融合器在颈前路椎间盘切除融合术治疗多节段脊髓型颈椎病中的应用价值

【摘要】 目的：探讨零切迹融合器（Zero-P VA）在颈前路椎间盘切除融合（anterior cervical discectomy and fusion,ACDF）术治疗多节段脊髓型颈椎病（multilevel cervical spondylotic myelopathy,MCSM）中的应用价值。方法：回顾性分析2018年8月～2020年8月期间在我科行ACDF治疗的55例MCSM患者的临床资料,其中应用Zero-P VA治疗27例（Zero-P组）,应用传统融合器＋钛板固定治疗28例（钛板组）。观察两组患者的手术时间、术中出血量、融合节段椎间高度和颈椎Cobb角。采用颈部疼痛视觉模拟评分（VAS）、颈椎功能障碍指数（neck disability index,NDI）、日本骨科协会（Japanese Orthopaedic Association,JOA）评分、Bazaz吞咽困难评分及植骨融合率进行临床疗效对比分析。结果：55例患者均顺利完成手术并获得完整随访,随访时间14～35个月,平均23.17±4.75个月。与术前相比较,两组患者术后VAS评分、NDI指数和JOA评分均有明显的改善,差异均有统计学意义（P＜0.05）,但两组之间无统计学差异（P＞0.05）。Zero-P组手术时间3节段为95.47±5.24min,4节段为115.12±7.53min,较钛板组手术时间（3节段130.85±6.97min和4节段155.69±9.28min）显著缩短,差异有统计学意义（P＜0.05）;术中出血量两组差异无统计学意义（P＞0.05）。Zero-P组颈椎Cobb角在术后3个月时为16.71°±1.28°,末次随访时为15.69°±0.26°,均优于术前（10.53°±1.36°）,差异有统计学意义（P＜0.05）;钛板组颈椎Cobb角术后3个月时为16.95°±2.64°,末次随访时为16.01°±1.71°,优于术前（10.67°±0.41°）,差异有统计学意义（P＜0.05）;而两组之间各时间点颈椎Cobb角的差异均无统计学意义（P＞0.05）。Zero-P组术后1例（3.70%）发生椎前异物感,术后1个月完全消失,无吞咽困难发生,未见相邻节段退变加速。钛板组术后4例（14.29%）发生椎前异物感,于术后2～4个月逐渐消失;术后3例（10.71%）发生吞咽困难,其中轻度1例（3.57%）,中度2例（7.14%）,3例患者在术后3～6个月逐渐好转,1例（3.57%）出现声音嘶哑,于术后2年取出钛板,患者声音嘶哑无明显改善;2例（7.14%）患者出现相邻节段（C2/3）退变加速,均未出现临床症状,予以保守观察。两组的吞咽困难发生率及相邻节段退变发生率间存在显著性差异（P＜0.05）。术后3个月时,Zero-P组植骨融合率为88.89%,钛板组植骨融合率为92.86%,末次随访时两组患者均达到有效植骨融合,但两组间植骨融合率无明显差异（P＞0.05）。两组患者均无硬脊膜损伤、食管损伤、神经根损伤、椎前血肿、伤口感染、假关节形成等并发症。结论：在ACDF治疗多节段脊髓型颈椎病中,使用零切迹融合器能够达到与传统融合器+钛板固定一致的临床疗效,和重塑颈椎曲度并恢复颈椎间隙高度的作用,并且手术时间短,术后患者吞咽困难、相邻节段退变发生率低。     

颈椎椎板成形椎管扩大术结合椎弓根螺钉矫形内固定融合术治疗多节段压迫性颈脊髓病合并退变性颈椎后凸的中长期疗效

【摘要】 目的：观察颈后路椎板成形椎管扩大术结合椎弓根螺钉矫形内固定融合术治疗多节段压迫性颈脊髓病合并退变性颈椎后凸患者的中长期疗效。方法：回顾性分析2008年3月~2019年9月，采用颈后路单开门椎板成形椎管扩大术结合椎弓根螺钉矫形内固定融合术治疗的18例多节段脊髓受压的慢性颈脊髓病合并退变性颈椎后凸患者，其中男11例，女7例，年龄52.3±8.1岁；颈椎后纵韧带骨化症（ossification of posterior longitudinal ligament，OPLL）合并慢性颈脊髓病5例，脊髓型颈椎病13例。减压节段：17例为C3~C7，1例为C3~T1，术中固定融合3.8±1.0个椎体。12例患者出院时（术后2周左右）复查颈椎MRI，11例患者获得随访，随访时间2.1~13.5年（10.5±2.8年）。在术前、出院时颈椎侧位X线片上测量后凸节段Cobb角，在颈椎MRI上测量脊髓前缘角及改良K线，末次随访时在X线片上评估手术固定节段骨性融合及后凸矫形角度丢失情况。术前及末次随访时进行JOA评分及颈痛VAS评分。结果：18例患者术前后凸节段的局部Cobb角为6.6°±6.5°后凸，术后2周为3.8°±8.0°前凸，有显著性差异（P<0.01）； 术前C2~C7颈椎Cobb角为1.3°±9.4°前凸，术后2周为5.8°±7.0°前凸，无显著性差异（P＞0.05）。12例患者颈椎MRI上测量脊髓前缘角术前为11.1°±4.2°后凸，术后2周为1.3°±5.2°后凸，有显著性差异（P<0.01）；C2~C7节段脊髓前缘角术前为6.5°±4.4°后凸，术后2周为1.1°±6.3°前凸，有显著性差异（P<0.01）。7例（39%）患者术后出现C5神经根麻痹，均在术后1~4个月内完全恢复。术后末次随访11例患者颈椎侧位X线片显示手术固定节段均获骨性融合，后凸矫形角度无丢失；颈椎MRI显示脊髓无受压，正中矢状位片显示脊髓前缘角无丢失。11例患者JOA评分术前8.0±2.8分，末次随访时15.6±0.9分，有显著性差异（P<0.01），JOA评分改善率（83±14）%；颈痛VAS评分术前为2.2±3.0分，末次随访时为1.1±1.2分，术前与末次随访时相比无显著性差异（P>0.05）。结论：对于合并有退变性颈椎后凸的多节段受压的慢性压迫性颈脊髓病，采用椎板成形椎管扩大术结合椎弓根螺钉矫形内固定融合术可以获得长期稳定、良好的脊髓功能改善的效果。     

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.