单开门颈椎管扩大椎板成形术治疗颈椎后纵韧带骨化症的中远期疗效观察

目的 :评估单开门颈椎管扩大椎板成形术治疗颈椎后纵韧带骨化症(OPLL)的中远期临床疗效。方法 :回顾性分析2005年3月~2012年4月在北京大学第三医院接受单开门颈椎管扩大椎板成形术的44例颈椎OPLL患者。其中,男26例,女18例;年龄57.1±8.5岁(28~72岁);术前改良JOA 17分法评分为11.39±3.27分(1.5~16分),颈痛VAS评分为2.32±2.59分(0~10分)。OPLL骨块累及3.20±1.64个(1~6个)椎体节段,骨块的椎管侵占率为(46.05±13.67)%(22%~72%)。手术范围:C3~C7 34例,C2~C7 7例,C2~C6 3例。术前及末次随访时分别测量颈椎侧位X线片上颈椎整体曲度及曲度指数、颈椎MRI中矢状位T2加权像C2/3~C6/7各节段脊髓整体后移距离(PCS)、脊髓前缘后移距离(PAS)、脊髓膨胀度(ESC)。结果:所有患者均获得随访,随访36.8±16.8个月(24~96个月)。末次随访时,JOA评分为14.70±1.96分(9.5~17分),颈痛VAS评分为3.59±2.97分(0~10分),与术前比较均有统计学差异(P0.05)。末次随访时JOA评分改善率为(57.59±30.88)%,其中神经功能恢复为优者12例,良19例,不理想13例,优良率为70.45%。末次随访时的颈椎曲度指数、颈椎整体曲度与术前比较无统计学差异(P0.05)。末次随访时,C2/3~C6/7各节段脊髓均有明显后移、脊髓前后径增加,PCS及PAS在C3/4~C6/7节段均明显高于C2/3节段(P0.05);而ESC在C3/4~C5/6节段明显高于C2/3及C6/7节段(P0.05)。10例患者末次随访时(术后2~8年)观察到OPLL骨块继续生长。结论:单开门颈椎管扩大椎板成形术治疗颈椎OPLL可获得脊髓症状的中长期缓解,但轴性症状较术前加重。减压节段的头端脊髓后移及膨胀程度幅度较小,应注意保证该节段的充分减压。     

颈椎后路单开门椎管扩大成形术治疗多节段压迫性颈脊髓病

目的评估颈椎后路单开门椎管扩大成形术治疗多节段压迫性颈脊髓病的临床效果,探讨手术相关问题及处理方法。方法对2014年3月至2016年3月河南省洛阳正骨医院收治的44例行颈椎后路单开门椎管扩大成形术的多节段压迫性颈脊髓病患者的临床资料进行回顾性分析,评估患者手术前后日本骨科学会(JOA)颈髓功能评分,记录围手术期并发症发生情况。结果手术开门角度13°~51°,平均开门角度(25±4)°;开门距离9~27 mm,平均开门距离(13±4)mm。随访5~24个月,平均随访时间13个月。术后椎管有效面积扩大,患者症状均有不同程度减轻。术前、术后末次随访JOA评分分别为(8.1±3.7)和(12.0±2.9)分,手术前后比较,差异有统计学意义(P0.05),术后脊髓功能平均改善率(43±18)%。2例患者术中出现脑脊液漏,3例有轴性症状,1例开门侧C5神经根麻痹,1例术后10 d颈椎MRI提示两节段门轴侧内层皮质断裂、门轴塌陷;后期恢复均良好。随访期间无一例患者出现切口感染、硬膜外血肿、瘢痕组织粘连或再关门并发症。结论对于多节段压迫性颈脊髓病患者,颈椎后路单开门椎管扩大成形术可取得显著疗效,但需注意手术减压范围、开门角度及围手术期并发症等问题。     

多节段脊髓型颈椎病术前颈椎曲度对椎管扩大椎板成形术术后神经功能恢复影响

目的探讨多节段脊髓型颈椎病患者术前颈椎曲度与椎管扩大椎板成形术术后神经功能之间的相关性。方法选取2013年1月—2015年12月在第二军医大学附属长征医院实施椎管扩大椎板成形术的70例多节段脊髓型颈椎病患者作为研究对象进行回顾性分析。按照患者术前X线片中的颈椎曲度将患者分为曲度正常组(A组)、曲度变直组(B组)、轻度曲度后凸组(C组),比较3组患者术后各节段脊髓后移距离、神经功能恢复率,并探讨术前颈椎曲度、术后脊髓后移距离与神经功能恢复率之间的相关性。结果 3组患者术后各节段脊髓后移距离组间差异无统计学意义(P0.05)。3组患者术前、术后的组间日本骨科学会(JOA)评分、神经功能恢复率差异均无统计学意义(P0.05);与术前相比,术后3组患者的JOA评分均明显增高,差异具有统计学意义(P0.05)。颈椎曲度与神经功能恢复率、脊髓后移距离之间无相关性。结论术前颈椎曲度变直及轻度后凸的多节段脊髓型颈椎病患者在实施椎管扩大椎板成形术后脊髓神经功能均可改善,曲度变直及轻度后凸可能不再是多节段脊髓型颈椎病行椎管扩大椎板成形术的禁忌证。     

影响椎管扩大成形术治疗多节段脊髓型颈椎病疗效的术前因素分析

目的探讨单开门椎管扩大成形术治疗多节段脊髓型颈椎病的疗效,分析术前因素为判断患者预后提供一定依据。方法 2013年6月至2016年11月,我科收治多节段脊髓型颈椎病并接受单开门椎管扩大成形术治疗获得随访患者47例,其中男29例,女18例;年龄36～72岁,平均(55.26±9.30)岁。测量患者的颈椎曲度、脊髓信号强度、脊髓受压程度。多元线性回归分析日本骨科协会(Japanese orthopaedic association,JOA)评分改善率与年龄、病程、颈椎曲度、脊髓信号强度、脊髓受压程度、术前JOA评分的关系。结果 47例患者均获得随访,随访时间14～19个月,平均16.5个月。JOA评分由术前的(9.23±1.18)分升至末次随访时的(13.23±1.66)分,平均改善率为(51.93±19.03)%。改善率与病程、脊髓信号强度、脊髓受压程度之间有直线相关关系。进入逐步回归方程的因素有脊髓受压程度、病程、脊髓信号强度,标准化回归系数依次是-0.224、-0.344、-0.406。结论单开门椎管扩大成形术是治疗多节段脊髓型颈椎病的有效方法,影响改善率的主要因素是脊髓受压程度、病程、脊髓信号强度。     

硬脊膜松解对椎管扩大成形术治疗伴后纵韧带骨化的多节段脊髓型颈椎病疗效的影响

目的探讨硬脊膜松解对颈后路椎管扩大成形术治疗伴后纵韧带骨化的多节段脊髓型颈椎病疗效的影响。方法回顾分析2011年2月-2013年10月,32例行椎管扩大成形术联合硬脊膜松解的伴后纵韧带骨化的多节段脊髓型颈椎病患者临床资料(A组),并与2010年1月-2011年1月36例单纯行椎管扩大成形术的患者(B组)进行比较。两组性别、年龄、病程、累及节段、合并内科疾病以及术前颈椎屈曲度、日本骨科协会(JOA)评分、疼痛视觉模拟评分(VAS)比较,差异均无统计学意义(P0.05),具有可比性。比较两组术后JOA评分及其改善率、VAS评分以及脊髓后移距离、颈椎曲度变化。结果术中3例出现硬脊膜撕裂,其中A组2例、B组1例;术后3例发生脑脊液漏,其中A组2例、B组1例。患者均获随访,随访时间12~46个月,平均18.7个月。末次随访时,两组JOA评分及VAS评分均较术前显著改善(P0.05);A组JOA评分及改善率显著高于B组(P0.05),VAS评分显著低于B组(P0.05)。末次随访时,两组颈椎曲度比较差异无统计学意义(P0.05);A组脊髓后移距离大于B组(P0.05)。随访期间均未出现椎板再关门。结论对伴后纵韧带骨化的多节段脊髓型颈椎病,颈后路椎管扩大成形术中进行充分硬脊膜松解,有利于脊髓后移,与单纯椎管扩大成形术相比,疗效显著提高。     

颈椎后路减压术后脊髓后移的临床意义

 目的 探讨颈椎后路全椎板减压和椎管成形术后脊髓后移对多节段脊髓型颈椎病的临床 意义。方法 回顾性分析 2004年 6月至 2007年 9月 65例多节段脊髓型颈椎病患者的病例资料, 男 41例, 女 24例;年龄 39~75岁, 平均 56.3岁。 33例采用颈后路选择性椎板切除术(切除组), 32例采用 颈后路单开门椎管成形术(开门组)。两组患者术前日本矫形骨科学会(Japanese Orthopaedics Associa tion, JOA)评分、颈椎曲度指数的差异无统计学意义。术后 1年, 评估两组的脊髓后移距离、神经功能 (JOA评分)改善率、颈椎曲度指数丢失及轴性症状评分。结果 全部病例均获得 26~47个月的随访, 平均 34个月。切除组术后 1年脊髓后移距离(1.4±0.6) mm, 开门组(3.3±1.2) mm,差异有统计学意义;切除组 JOA评分改善率 60.5%±21.3%, 开门组 61.1%±17.9%,差异无统计学意义;切除组颈椎曲度指数丢失 3.3%±1.7%, 开门组 3.1%±2.4%, 差异无统计学意义;切除组 18.2%(6/33)的患者术后有明显轴性症状, 开门组为 33.3%(10/30), 两组轴性症状临床评分的差异有统计学意义。结论 选择性椎板切除术后脊髓后移距离小于单开门椎管成形术。脊髓后移程度与术后功能恢复程度及颈椎曲度无关, 而与轴性症 状有关。     

保留双侧半棘肌单开门与传统单开门椎管扩大成形术治疗多节段颈脊髓压迫症的疗效比较

目的 :比较保留双侧半棘肌的改良颈椎单开门与传统单开门椎管扩大成形术治疗多节段颈脊髓压迫症的疗效。方法:回顾分析2013年1月~2014年5月在我科行颈椎单开门椎管扩大成形术的66例多节段颈脊髓压迫症患者的临床资料。均行C3~C6单开门椎管扩大成形术,按手术方式分为保留C2、C7双侧半棘肌止点的传统单开门椎管扩大成形术(传统组)36例和保留双侧半棘肌的改良单开门椎管扩大成形术(改良组)30例。记录两组手术时间、术中出血量,记录术前、术后3个月及末次随访时两组病例的视觉模拟评分法(visual analogue scale/score,VAS)评分、JOA评分、颈部功能障碍指数(neck disability index,NDI)评分、颈椎总活动度(ranges of motion,ROM)、颈椎曲度及术后轴性症状的严重程度。结果 :传统组手术时间为140.49±36.57min,改良组为122.35±46.57min,差异无统计学意义(P0.05)。传统组术中出血量为233.66±165.39ml,改良组为281.18±208.11ml,差异无统计学意义(P0.05)。传统组2例、改良组1例患者出现C5神经根麻痹,给予甲基强的松龙、营养神经药物等治疗后,症状明显好转。术后无脊髓损伤、门轴断裂、脑脊液漏、硬膜外血肿、感染,无内置物松动或断裂。两组患者均获随访,随访时间12~24个月,传统组随访时间为17.10±3.57个月,改良组为16.40±2.57个月,差异无统计学意义(P0.05)。传统组末次随访时JOA评分改善率为(71.36±8.14)%,改良组为(72.95±14.41)%,差异无统计学意义(P0.05)。NDI评分,术前及术后3个月传统组与改良组比较无统计学差异(P0.05),末次随访时组间差异有统计学意义(P0.05),组内比较术前及末次随访时NDI评分差异有统计学意义(P0.05)。VAS评分,术前组间比较无统计学差异(P0.05),但术后3个月及末次随访时组间差异有统计学意义(P0.05),组内术前及末次随访时VAS评分差异有统计学意义(P0.05)。末次随访时,传统组颈椎曲度较术前减少3.73°±1.38°,改良组较术前减少1.47°±1.01°,差异有统计学意义(P0.05);传统组ROM较术前减少6.63°±2.09°,改良组较术前减少4.53°±1.70°,差异有统计学意义(P0.05)。传统组11例(30.56%)、改良组1例(3.33%)术后发生轴性症状或加重,组间比较差异有统计学意义(P0.05)。结论:与传统单开门手术相比,保留双侧半棘肌的单开门椎管扩大成形术在治疗多节段颈脊髓压迫症时,可最大限度保留颈椎后方结构,减少轴性症状的发生率和颈椎曲度及ROM的丢失。     

颈后路单开门椎管扩大成形术治疗多节段脊髓型颈椎病疗效分析

目的探讨颈后路单开门椎管扩大成形术治疗多节段脊髓型颈椎病的疗效及影响因素。方法对76例多节段脊髓型颈椎病患者行后路单开门椎管扩大成形术,术前术后进行JOA评分及Hirabayashi改善率评分。结果 76例均获随访,时间6～36(24.6±10.2)个月。JOA评分:术前为9.5分±2.41分,术后为12.92分±1.69分(P<0.05)。术后患者神经功能有不同程度的改善,末次随访改善率为54.60%±15.52%。结论颈后路单开门椎管扩大成形术能有效地解除脊髓的压迫,改善神经功能,疗效肯定。年龄、病程、术前JOA评分对脊髓功能改善率影响显著,年龄越大、病程越长、术前JOA评分越低的患者,术后脊髓功能改善越差。     

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。     

改良颈椎后路单开门椎管扩大成形术治疗多节段脊髓型颈椎病的疗效观察

目的比较改良颈椎后路单开门椎管扩大成形术与传统颈椎后路单开门椎管扩大成形术治疗多节段脊髓型颈椎病的临床疗效。方法回顾性分析自2016-05—2019-03诊治的80例多节段脊髓型颈椎病,40例采用改良颈椎后路单开门椎管扩大成形术治疗(改良组),40例采用传统颈椎后路单开门椎管扩大成形术治疗(传统组)。比较2组手术时间、术中出血量、住院时间、术后出现轴性症状数以及末次随访时的疼痛VAS评分、JOA评分、JOA评分改善率、Tsuji轴性症状评分。结果 80例均顺利完成手术,随访时间平均15.0(7～28)个月。改良组术后出现轴性症状数、术中出血量较对照组少,差异有统计学意义(P0.05)。2组手术时间、住院时间比较差异无统计学意义(P0.05)。末次随访时2组疼痛VAS评分、JOA评分、JOA评分改善率、Tsuji轴性症状评分比较差异无统计学意义(P0.05)。结论改良颈椎后路单开门椎管扩大成形术与传统颈椎后路单开门椎管扩大成形术治疗多节段脊髓型颈椎病均能取得满意的临床疗效,但前者能有效降低术中出血量,简化手术步骤,术后可有效减少轴性症状的发生率。     

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.