颈椎前路减压植骨融合钢板内固定术后邻近节段退变的危险因素研究

目的探讨颈椎前路减压植骨融合钢板内固定术(anterior Cervical discectomy and fusion,ACDF)后邻近节段退变(adjacent segment degeneration,ASD)的危险因素。方法纳入2013年2月～2016年2月行ACDF术的133例颈椎病患者,随访30～50个月。依据术后发生ASD与否,将患者设为ASD组(40例)与非ASD组(93例)。调查两组患者性别、年龄等临床资料以及手术前后弧弦距、椎间撑开高度等影像资料。经单因素分析、Logistic回归分析调查术后ASD发生的独立危险因素。结果单因素分析显示,ASD组与非ASD组年龄、术后弧弦距、椎间撑开高度、术后椎体边缘与钢板距离、融合节段数、术后融合节段Cobb角差异具有统计学意义(P0.05),多因素Logistic回归分析显示,年龄(OR=2.103)、术后弧弦距(OR=1.981)、椎间撑开高度(OR=2.321)、术后椎体边缘与钢板距离(OR=2.201)、融合节段数(OR=1.875)是颈椎病ACDF后ASD的独立危险因素。结论颈椎病ACDF后ASD发生率较高,年龄、术后弧弦距、椎间撑开高度、术后椎体边缘与钢板距离、融合节段数均是其独立影响因素。     

颈前路融合术后相邻节段病诊治分析

目的探讨颈椎前路减压融合术后相邻节段病(ASD)的发病因素、治疗方法及疗效。方法将随访时间≥3年的451例行颈前路融合术患者(1节段189例,2节段176例,3节段71例,3节段15例)根据是否再发与影像学一致的颈椎病的临床表现分为ASD组与非ASD组。比较两组年龄、性别、内固定与否、JOA评分、D值、融合节段分布、融合节段数的差异。同时对非手术治疗无效的ASD患者行颈椎前路减压融合术治疗,采用JOA评分和D值对ASD术后疗效进行评价。结果患者均获得随访,时间3～15年,共有46例出现ASD。ASD组与非ASD组在年龄、性别、JOA评分、融合节段分布、融合节段数比较差异均无统计学意义(P0.05);在钢板内固定与否、D值改变两项比较差异有统计学意义(P0.05)。对21例非手术治疗无效的ASD患者行颈前路手术,患者术后随访15～86个月,均获得骨性融合,未见顽固性并发症,末次随访时JOA评分为14.24分±2.17分,比术前的9.14分±1.22分升高(P0.05);末次随访时D值为5.33 mm±3.61mm,比术前的1.78 mm±1.49 mm增加(P0.05)。结论 ASD的发生与颈椎前路手术中钢板使用和颈椎曲度恢复不良有关,对于非手术治疗失败的ASD患者采用颈椎前路减压融合术治疗可取得满意效果。     

颈椎前路减压分段融合术和后路椎管扩大成形术治疗多节段脊髓型颈椎病的病例对照研究

目的 :比较颈椎前路减压分段融合术和后路椎管扩大成形术治疗多节段脊髓型颈椎病的临床疗效。方法:对2009年7月至2012年6月收治的56例多节段脊髓型颈椎病病例进行回顾性分析,男32例,女24例;年龄42~79岁,平均(56.9±12.8)岁,病程2个月~16年,平均(10.6±3.2)年。所有患者术前经影像学检查显示有多节段颈椎间盘突出,并具有脊髓型颈椎病的临床表现。其中34例采用颈椎前路减压分段融合术(前路组),22例采用后路椎管扩大成形术(后路组)。通过影像学资料对两组患者手术前后的病变节段前柱高度和颈椎前曲度进行比较,并采用JOA评分评价手术效果。结果:两组患者无神经血管并发症发生,并获得24~36个月的随访(平均28.6个月)。前路组,术后2周时颈椎病变节段前柱高度较术前明显增高(P0.05),颈椎前曲度较术前明显降低(P0.05)。后路组,术后2周及末次随访时,病变节段前柱高度和颈椎前曲度较术前差异均无统计学意义(P0.05)。两组间在术后2周及末次随访时颈椎前曲度差异有统计学意义(P0.05)。术后两组JOA评分均出现了明显恢复,术后3个月及末次随访时,前路组明显高于后路组(P0.05),且JOA评分改善率前路组也优于后路组(P0.05)。结论:这种分段式前路融合手术可以有效地恢复颈椎前柱高度,并且与颈椎后路椎管扩大成形术相比,可以显著地改善脊髓功能,是治疗多节段脊髓型颈椎病的有效方案。     

Prodisc-C假体行全颈椎人工间盘置换术后十年以上随访远期疗效评估

目的对Prodisc-C假体行全颈椎人工间盘置换术(total cervical disc replacement,TDR)患者10年以上远期疗效进行评价。方法回顾分析2005年12月—2008年4月采用Prodisc-C假体行TDR治疗的118例单节段至3节段颈椎间盘退变疾病(cervical disc degeneration disease,CDDD)患者临床资料。其中男66例,女52例;年龄25～62岁,平均46.8岁。神经根型颈椎病38例,脊髓型颈椎病28例,混合型颈椎病52例。手术节段为C3～7,其中单节段90例,连续双节段20例,连续3节段8例。术中共使用154个Prodisc-C假体。手术前后临床疗效采用疼痛视觉模拟评分(VAS)、颈椎功能障碍指数(NDI)、日本骨科协会(JOA)评分、Odom分级评价。影像学评价指标包括颈椎活动度(range of motion,ROM)、矢状位前凸角、椎间隙高度(intervertebral disc height,IDH),并观察有无假体移位、下沉、松动、锁死及异位骨化(heterotopic ossification,HO)、邻近节段退变(adjacent segment degeneration,ASD)等并发症发生。并根据有无发生HO或ASD分组,比较患者手术节段ROM。结果术后患者均获随访,随访时间121～150个月,平均135.8个月。随访期间无1例行翻修手术。术后1周及末次随访时VAS、NDI、JOA评分及Odom分级均较术前显著改善(P0.05);其中末次随访时VAS和NDI评分较术后1周进一步改善(P0.05);术后1周及末次随访时的JOA评分及改善率比较差异无统计学意义(P0.05)。颈椎整体和手术节段ROM在术后1周和10年后较术前有所减小(P0.05),其余各时间点差异均无统计学意义(P0.05);上位邻近节段(upper adjacent segment,UAS)和下位邻近节段(lower adjacent segment,LAS)的ROM术后各时间点间比较差异均无统计学意义(P0.05)。手术前后各时间点颈椎矢状位前凸角比较差异均无统计学意义(P0.05);手术节段前凸角在术后1周、6个月、1年、2年较术前显著增加(P0.05)。术后各时间点手术节段IDH均较术前显著改善(P0.05),而术后各时间点间UAS和LAS的IDH比较差异均无统计学意义(P0.05)。术后各时间点均未发生假体移位、下沉和松动;从术后6个月起,各时间点间假体移位和下沉距离比较差异均无统计学意义(P0.05)。而末次随访时假体锁死/融合发生率达10.4%,但与术后6个月(1.9%)比较差异有统计学意义(P0.05)。术后1周上位ASD和下位ASD发生率分别为1.3%和2.6%,随时间延长其发生率逐渐增加,各时间点间比较差异均有统计学意义(P0.05);ASD组患者术后各时间点手术节段ROM均小于无ASD组,但差异无统计学意义(P0.05)。术后6个月起有58.4%节段出现HO,随时间延长HO发生率均较术后6个月逐渐显著增加(P0.05);HO组患者手术节段ROM在术后6个月、2年、5年、10年显著小于无HO组患者(P0.05)。结论 TDR术后对邻近节段影响较小,尽管出现部分影像学并发症,但对整体临床疗效的改善无明显影响;使用Prodisc-C假体行TDR治疗CDDD可获得安全、明确的远期临床疗效。     

后路L4/5融合术后邻椎病发生的危险因素

【摘要】 目的：探讨后路L4/5融合术后邻椎病（adjacent segment disease，ASD）发生的危险因素。方法：回顾性分析2012年9月~2021年9月因后路L4/5融合术后ASD于我院接受翻修手术的26例患者，纳入ASD组；采用1∶2匹配的方法，从同期接受腰椎后路融合手术且末次随访时未发生ASD的患者中，按性别、手术时年龄、手术节段、随访时间匹配52例患者作为对照组。收集两组患者术前、术后3d、末次随访时的影像学资料，在腰椎侧位X线片上测量：腰椎前凸角（lumbar lordosis，LL）、节段性前凸（segmental lordosis，SL）、骶骨倾斜角（sacral slope，SS）和L3/4、L4/5、L5/S1的椎间隙相对高度；在初次术前MRI上，采用Pfirrmann分级对融合节段邻近节段椎间盘退变情况进行评估。将两组患者术前基线资料，术前、术后3d、末次随访时的腰椎影像学资料（包括腰椎矢状位参数和初次术后腰椎矢状位参数矫正值）进行比较，将有差异的参数进行多因素Logistic回归分析，通过受试者工作特征（receiver operating characteristic，ROC）曲线确定独立危险因素对ASD的最佳预测阈值。结果：ASD组与对照组在术前第一诊断、术前邻近节段椎间盘的Pfirrmann分级、合并症情况均无统计学差异（P>0.05）。ASD组患者初次接受手术后5.4±2.3年行二次手术，二次手术融合节段L3/4 16例，L5/S1 10例。两组术前SL、SS以及L4/5、L3/4和L5/S1椎间隙相对高度均无显著性差异（P＞0.05），ASD组患者初次术前LL显著性小于对照组（P=0.031）。初次融合术后3d，ASD组SL和LL显著性小于对照组（P＜0.05）。末次随访时，ASD组SL和LL均显著小于对照组（P<0.001）；ASD组的L3/4椎间隙相对高度明显小于对照组（P=0.002）。两组初次手术各参数的矫正值相比，ASD组的SL相对差值（relative △SL，r△SL）显著性小于对照组（P<0.001），两组间LL相对差值（relative △LL，r△LL）、L4/5椎间隙高度相对差值（relative △disc height，r△DH）、L3/4 r△DH、L5/S1 r△DH均无显著性差异（P>0.05）。以ASD为因变量的多元回归分析结果显示较小的初次r△SL是发生ASD的独立危险因素（OR=0.031，95%置信区间0.005~0.209），其曲线下面积（area under curve，AUC）为0.731（95%置信区间0.615~0.848），最佳预测阈值为-10.5%。结论：后路L4/5融合术中局部曲度纠正不足可能会导致远期邻近节段高度的丢失，是融合术后发生ASD的独立危险因素。     

平山病患者颈椎曲度和相邻节段椎体屈曲度与脊髓萎缩的相关性

目的:观察平山病患者颈椎曲度、相邻节段椎体屈曲度与脊髓萎缩的相关性,为手术治疗平山病提供依据.方法:对2006年10月～2010年10月我院确诊的36例平山病患者进行回顾性分析.术前均行颈椎侧位、过伸、过屈位X线片检查与中立位MRI检查.在X线片上用Borden法测量C2～C7颈椎曲度(颈椎生理曲线的深度,即弧弦距),用椎体后缘切线法测量C3～C7相邻椎体曲度在中立位与屈曲位时的差值即为相邻椎体屈曲度:在中立位MRI上观察矢状位脊髓萎缩情况,测量C3～C7各节段椎体上缘水平脊髓横断面面积.根据颈椎曲度测量结果,将患者分为:颈椎正常前凸,7mm≤弧弦距≤17mm;颈椎变直或轻度后凸,1mm＜弧弦距＜7mm;颈椎中度后凸,-4mm＜弧弦距≤1mm;颈椎重度后凸,弧弦距≤-4mm.对各相邻椎体屈曲度与中立位MRI上相应节段颈髓的横断面积进行相关性分析.结果:颈椎正常前凸8例;颈椎变直或轻度后凸13例;中、重度后凸15例,其中14例后凸顶椎为C5,1例为C4.在中立位MRI上,共有14例颈脊髓萎缩变细,分布集中在C4～C7节段.颈椎曲度变直及后凸的患者脊髓萎缩的发生率为13/28,明显高于颈椎正常前凸患者的1/8 (P＜0.01).C3～C7各相邻椎体屈曲度之间有显著性差异(P＜0.05),C5～C7椎体屈曲度较C3～C5更大(P＜0.05).各相应节段脊髓面积也有显著性差异(P＜0.05),C5～C7颈脊髓横截面积较C3～C5更小(P＜0.05).相邻节段之间的屈曲度与相应节段脊髓横截面积之间呈负相关(r=-0.205,P＜0.05),C5～C6相邻椎体屈曲度与相应脊髓横截面积之间呈负相关(r=-0.536,P＜0.05).结论:颈椎曲度及相邻节段椎体屈曲度的异常改变是平山病的重要特征,可能是导致平山病患者颈脊髓萎缩的重要因素,手术治疗平山病的关键在于限制颈椎过度活动,恢复颈椎正常曲度.     

腰椎融合术后发生邻近节段退变的相关因素分析

目的探讨腰椎退行性疾病行腰椎融合手术后,发生邻近节段退变(Adjacentsegment degeneration,ASD)的相关因素。方法自2011-09-2014-09,共纳入287例行腰椎后路融合手术治疗的腰椎退行性疾病患者,均由同一组医师进行腰椎融合手术,术后随访37-60个月。依据其术后是否发生ASD,将其分为ASD组23例和非ASD组264例,统计两组患者的性别、年龄、手术方式、术中是否进行椎板切除、是否行悬浮固定,邻近节段椎间盘再术前是否存在退变等相关数据。将上述数据作为自变量,并将ASD发生与否作为因变量,进行与ASD相关的组间单因素分析,以及多因素Logistic回归分析。结果单因素分析发现,年龄、手术方式、术前邻近节段有椎间盘退变,均与之关系密切;而进一步的多因素Logistic回归分析发现,手术方式为PLIF、术前有邻近节段的椎间盘退变、患者年龄在60岁以上,均是术后发生ASD的独立危险因素(均为P0.05)。结论在腰椎融合手术治疗腰椎退行性疾病中,年龄在60岁以上、采用PLIF术式、术前邻近节段有退变者,其术后发生ASD的风险较高。     

颈椎前路椎间隙减压融合固定致C_5神经根麻痹的影响因素分析

目的探讨颈椎前路椎间隙减压融合固定致上肢外展上举受限的相关因素。方法对255例颈椎病患者行颈椎椎间隙减压融合内固定术,根据术后患者是否出现上肢外展上举受限,将患者分为受限组(15例)和未受限组(240例)。采用JOA评分法评估患者术前、术后神经功能;采用颈椎功能障碍指数(NDI)评价颈椎疗效。分析影响上肢外展上举受限的影响因素。结果 255例患者均获得随访,时间7~12个月。15例术后上肢外展上举受限者颈椎JOA评分由术前(8.8±1.7)分提高至(13.8±2.3)分;颈椎NDI评分由术前平均(9.7±2.2)分下降至末次随访时的(2.5±1.5)分。术后C4~5椎间盘退变评分、C_(4~5)节段椎间隙高度增加量受限组与未受限组比较差异无统计学意义(P0.05);受限组中,术前C_(3~5)脊髓信号改变比率为8/15(53.3%),明显高于未受限组的3/240(1%),差异有统计学意义(P0.01)。受限组者中,手术节段≤2个者上肢受限发生率(3/15)显著低于手术节段3个者(12/15)。结论颈椎前路椎间隙减压融合固定后上肢外展上举受限的患者预后较好,患者多节段减压手术及术前C_(3~5)脊髓高信号为术后发生上肢外展上举受限的影响因素。     

颈椎前路椎间盘切除融合治疗脊髓型颈椎病后邻近节段退变的预测因素分析

目的探讨颈椎前路椎间盘切除融合治疗脊髓型颈椎病(Cervical spondylotic myelopathy,CSM)术后邻近节段退变(Adjacent segment degeneration,ASD)再手术的预测因素。方法选择2009年1月～2014年4月在本院行ACDF手术治疗的173例CSM患者,翻阅其病历资料,记录年龄、性别、体质量指数(Body mass index,BMI)、吸烟史、饮酒史、糖尿病史、症状持续时间、融合程度、融合节段、T2WI强信号强度、术前颈部VAS评分、术前上肢VAS、颈部NDI指数和JOA评分,以及C_2～C_7Cobb角、C_2～C_7运动范围(Range of motion,ROM)、C_2～C_7的矢状垂直轴(Sagittal vertical axis,SVA)、T1斜率等相关资料,观察所有患者术后的ASD发生情况,采用单因素和多因素分析,探讨上述因素与症状性ASD患者再手术的相关性。结果 5年内因ASD再手术31例,发生率17. 92%。单因素分析显示,ASD和非ASD患者年龄、症状持续时间、融合节段数、融合水平、C_2-C_7Cobb角、C_2-C_7SVA、T1斜率、T2WI强信号、术前颈部VAS、术前上肢VAS、术前NDI、术前JOA相比较存在统计学差异(P0. 05)。多因素分析显示,年龄、症状持续时间、融合水平、融合节段、术前颈部VAS、C_2-C_7SVA、术前NDI和术前JOA评分是影响ASD发生的风险因素(P0. 05)。结论多种因素均可影响ACDF患者术后ASD再手术的发生率,对颈椎矢状位失平衡、高龄、拟行多节段融合和症状严重的CSM患者,手术时应考虑到术后ASD的可能性。     

Solis融合器在前路颈椎椎间融合术治疗邻椎病中的应用

目的探讨Solis融合器在前路颈椎椎间融合术治疗邻椎病(ASD)中的应用,总结其在颈椎前路术后ASD翻修术中的临床疗效、优势及缺点。方法回顾性分析2007年4月—2016年6月收治的使用Solis融合器行颈椎前路手术后需行翻修术的12例ASD患者的临床资料,记录手术时间、术中出血量,通过患者术前、术后日本骨科学会(JOA)评分、颈椎功能障碍指数(NDI)、吞咽困难情况等评估神经功能,结合手术前后X线片、CT及MRI影像学表现评估临床疗效。结果所有患者术后随访4～114(61.8±29.3)个月。术后JOA评分、NDI均较术前明显改善,差异具有统计学意义(P 0.05)。所有患者翻修术后均未出现吞咽困难等并发症,复查颈椎正侧位X线片均证实获得骨性融合。结论 Solis融合器应用在颈椎前路手术后ASD翻修术中安全有效,具有暴露范围小、手术时间短、对原手术节段无干扰、术后吞咽困难发生率低等优点。     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.