脊柱－骨盆矢状位参数及关节突关节角度对退变性腰椎滑脱的影响

目的：探讨脊柱-骨盆矢状位参数及关节突关节角度对退变性腰椎滑脱的影响及相关性研究。方法：以2016年7月至2019年9月确诊的120例L₄-L₅单节段退变性滑脱患者为观察对象（滑脱组）,以性别和年龄相匹配的120例L₄-L₅节段退变性椎管狭窄患者为对照（对照组）。通过影像学资料测量如下参数：骨盆入射角（pelvic incidence,PI）,骨盆倾斜角（pelvic tilt,PT）,骶骨倾斜角（sacral slope,SS）,腰椎前凸（lumbar lordosis,LL）,胸椎后凸（thoracic kyphosis,TK）,矢状面平衡（sagittal vertical axis,SVA）,L₄-L₅头侧关节突关节角,尾侧关节突关节角及小关节不对称性。比较两组患者参数的差异并对有意义参数行Logistic回归分析。对退变性腰椎滑脱患者关节突关节方向与脊柱-骨盆参数进行相关性分析。结果：两组患者在PI、PT、LL、SVA、头侧关节突关节角、尾侧关节突关节角差异有统计学意义（P<0.05）;Logistic回归分析发现PI、PT及头侧关节突关节角是腰椎滑脱程度的危险因素（P<0.05）。滑脱组头侧关节突关节矢状化与PI、PT呈现显著相关（P<0.05）。结论：高PI、PT及头侧关节突关节矢状化是腰椎滑脱的危险因素,并且关节突关节矢状化程度和大PI、PT密切相关。     

Kümmell病伴脊柱后凸畸形对脊柱-骨盆矢状面参数的影响

目的：探讨Kümmell病伴脊柱后凸畸形对脊柱-骨盆矢状面形态的影响。方法：回顾性分析2015年8月至2022年9月收治的34例Kümmell病伴脊柱后凸畸形的患者（Kümmell病组）,其中男10例,女24例,年龄（71.1±8.5）岁,以37例年龄（69.3±6.7）岁匹配的无症状人群为对照组。在站立位全脊柱正侧位X线片上测量脊柱-骨盆矢状面参数,包括节段性后凸角（segmental kyphosis,SK）或胸腰椎后凸（thoracolumbar kyphosis,TLK）、胸椎后凸角（thoracic kyphosis,TK）、腰椎前凸角（lumbar lordosis,LL）,骨盆入射角（pelvic incidence,PI）、骨盆倾斜角（pelvic tilt,PT）、骶骨倾斜角（sacral slope,SS）、矢状面平衡（sagittal vertical axis,SVA）、T₁骨盆角（T₁ pelvic angle,TPA）以及骨盆入射角与腰椎前凸的匹配关系（PI-LL）。同时测量Kümmell病患者患椎椎体楔变角（wedge angle,WA）,并分析WA、SK等与脊柱-骨盆矢状面参数的相关性。结果：Kümmell病组TK、SK、PT、SVA、TPA、PI-LL均高于对照组（P<0.05）,Kümmell病组LL、SS低于对照组（P<0.05）;两组PI比较,差异无统计学意义（P>0.05）。Kümmell病组患椎WA为（30.8±5.9）°,并与SK、TK有相关性（r=0.366,0.597,P<0.05）,SK与LL、SS有相关性（r=0.539,-0.591,P<0.05）,LL与PI、SS、SVA、TPA、PI-LL有相关性（r=0.559,0.741,-0.273,-0.356,-0.882,P<0.05）。结论：Kümmell病伴脊柱后凸不仅存在节段性后凸畸形,而且整体脊柱-骨盆矢状面参数亦发生改变,包括腰椎前凸丢失、骨盆后旋、躯干前倾等。Kümmell病的手术治疗不仅要重视塌陷椎体高度的恢复,对于合并脊柱后凸患者还要着眼于脊柱-骨盆矢状面的整体平衡。     

复位在重度腰椎滑脱治疗中对脊柱骨盆参数的影响意义

目的：探讨复位在治疗成人重度腰椎滑脱中对脊柱骨盆平衡的作用及临床疗效。方法：回顾分析2008年8月至2011年8月应用后路复位技术治疗Ⅲ度及Ⅲ度以上（Meyerding分类）的成人腰椎滑脱患者16例,男9例,女7例;年龄24～65岁,平均44岁。通过脊柱全长侧位X线片测量比较术前、术后2周、末次随访脊柱-骨盆矢状位参数,包括骶骨倾斜角（sacral slope,SS）,骨盆倾斜角（pelvic tilt,PT）,骨盆入射角（pelvic incidence,PI）,腰椎前凸角（lumbar lordosis,LL）,矢状面轴向垂线（sagittal vertical axis,SVA）;三维重建CT判断骨融合情况;记录手术并发症;临床0swestry功能障碍评分（ODI）评估临床疗效。结果：16例患者均获随访,时间12～24个月,平均18个月。4例完全复位,8例复位至I度,4例复位至Ⅱ度;PI术前与术后2周无统计学差异（P>0.05）,术后2周与末次无统计学差异（P>0.05）;SS、PT、LL、SVA术前与术后2周比较有统计学差异（P<0.05）,术后2周与末次比较无统计学差异（P>0.05）.临床ODI评分由术前的36.6±4.2下降至末次随访时的14.7±4.0（P<0.05）.所有病例术后1年薄层螺旋CT扫描三维重建可见椎间骨小梁连接,达到骨性融合。3例出现神经根性疼痛,药物治疗后恢复;无感染、内固定松动及断裂。结论：手术复位在治疗成人重度腰椎滑脱中能够明显改善脊柱-骨盆矢状位排列,并获得良好疗效。     

双节段退行性腰椎滑脱症脊柱-骨盆矢状面参数特征

目的评估双节段退行性腰椎滑脱(dLDS)患者脊柱-骨盆矢状面失衡情况并探讨其代偿机制,为临床dLDS的诊治提供理论基础。方法回顾性分析2015年1月-2020年12月收治的80例Meyerding分级Ⅰ~Ⅱ级的退行性腰椎滑脱(LDS)患者资料,根据滑脱节段分为dLDS组(20例)和单节段LDS(sLDS)组(60例),另选取40例无症状志愿者作为对照组。在术前站立位全脊柱侧位X线片上测量各组的脊柱-骨盆矢状面参数,包括骨盆入射角(PI)、骨盆倾斜角(PT)、骶骨倾斜角(SS)、颈椎前凸角(CL)、胸椎后凸角(TK)、腰椎前凸角(LL)、下腰椎前凸角(LLL)、L₅入射角(L₅I)、矢状面偏移(SVA),并计算前凸分布指数(LDI)和PI-LL值(PI与LL的差值)。采用Oswestry功能障碍指数(ODI)和疼痛视觉模拟量表(VAS)评分对患者日常生活质量进行评估。结果 dLDS组和sLDS的PI、PT、L₅I、SVA、PI-LL均大于对照组,且dLDS组大于sLDS组,差异均有统计学意义(P < 0.05);dLDS组和sLDS的LLL、LDI均小于对照组,且dLDS组小于sLDS组,差异均有统计学意义(P < 0.05)。dLDS组的SVA、PI-LL、PT失衡发生率均高于sLDS组,差异有统计学意义(P < 0.05)。LDS患者均有不同程度腰腿痛,且dLDS组的ODI、下腰痛和腿痛VAS评分均高于sLDS组,差异均有统计学意义(P < 0.05)。相关分析结果显示,dLDS组ODI、下腰痛和腿痛VAS评分与PT、SVA、PI-LL呈正相关,与LL、LLL呈负相关。结论与sLDS患者相比,dLDS患者脊柱-骨盆矢状面参数改变更显著,矢状面失衡更严重,高PI值和L₅I值可能是dLDS发生发展的重要危险因素。     

高低位腰椎椎间盘突出症患者脊柱-骨盆矢状面形态变化

目的 比较高位与低位腰椎椎间盘突出症（LDH）患者脊柱-骨盆矢状面形态学差异，探讨脊柱-骨盆矢状面形态学参数异常与高位LDH发生的关系。方法 纳入2006年1月—2022年1月收治的高位LDH患者53例（高位组），同时期性别、年龄和体质量指数（MBI）匹配的低位LDH患者53例（低位组）及单纯下腰部疼痛的非LDH患者53例（对照组）。在站立位全脊柱侧位X线片上测量3组矢状面平衡（SVA）、胸椎后凸角（TK）、腰椎前凸角（LL）、腰骶前凸角（LSL）、骶骨倾斜角（ST）、骨盆入射角（PI）、骨盆倾斜角（PT）、骶骨倾斜角（SS）等脊柱-骨盆矢状面参数。结果 高位组SVA、TK明显高于对照组，LL、ST、PI、PT及SS明显低于对照组；高位组TK明显高于低位组，LL、ST及PI明显低于低位组；差异均有统计学意义（P<0.05）。高位组L₁/L₂节段患者的LL、ST较L₂/L₃节段患者有下降趋势，但差异无统计学意义（P>0.05）。结论 骨盆水平化导致的胸腰段过度代偿可能是高位LDH发生、发展的机制之一。     

退行性腰椎后滑脱的节段分布及与腰骶部矢状位平衡参数的关系

目的 探索腰椎后滑脱节段分布及与腰骶部矢状位平衡参数的相关性,揭示腰椎后滑脱发生机制。方法 选取2016年9月—2019年6月海军军医大学附属长征医院收治的腰椎后滑脱患者47例,调查其腰椎后滑脱节段分布规律,并将其分为上腰椎后滑脱组（L_1~3,34例）与下腰椎后滑脱组（L_4~5,13例）;选取同期入院的近似健康的患者29例作为对照组。比较3组患者腰椎前凸角（LL）、骶骨倾斜角（SS）、骨盆倾斜角（PT）、骨盆入射角（PI）的差异。结果 47例患者共56个节段后滑脱,其中L₁ 5例、L₂ 13例、L₃ 25例、L₄ 11例、L₅ 2例。与对照组相比,上腰椎后滑脱组LL、SS增大,PT减小,差异有统计学意义（P<0.05）,PI差异无统计学意义（P>0.05）;下腰椎后滑脱组LL、SS减小,PT增大,差异有统计学意义（P<0.05）,PI差异无统计学意义（P>0.05）。结论 腰椎后滑脱好发于L₃,其次为L₂、L₄。腰椎后滑脱与腰骶部矢状位失衡密切相关。当上腰椎后滑脱时,LL、SS增大,而PT减小;当下腰椎后滑脱时,LL、SS减小,甚至变为后凸,而PT增大。     

成人最大腰椎前凸预测公式的建立及评价

【摘要】 目的：建立一个新的预测成人最大腰椎前凸的公式,评价其可靠性和有效性。方法：收集311例健康成人的一般资料与站立位脊柱全长侧位X线片,在X线片上测量最大腰椎前凸（maximal lumbar lordosis,maxLL）、最大胸椎后凸（maximal thoracic kyphosis,maxTK）、骶骨倾斜角（sacral slope,SS）、骨盆倾斜角（pelvic tilt,PT）,骨盆入射角（pelvic incidence,PI）。应用Pearson相关分析在其中220例研究对象中分析maxLL与maxTK、SS、PT和PI之间的相关关系,利用与maxLL相关的变量进行多元回归分析,建立腰椎前凸预测公式;利用建立的公式对其余91例研究对象的maxLL进行预测,并与实际测量的maxLL进行比较,验证预测公式的可靠性与有效性。结果：maxLL与maxTK（r=0.564,P<0.001）、SS（r=0.783,P<0.001）、PT（r=-0.155,P=0.021）和PI（r=0.483,P<0.001）有关。多元回归分析表明maxLL与maxTK、PI显著相关性（P<0.001）,建立预测公式为：maxLL=0.6×maxTK+0.5×PI+3（R2=0.55）。用公式预测的maxLL为49.32°±7.06°,实际测量的maxLL为48.70°±9.46°,差异无显著性（P=0.408）。结论：maxTK与PI是maxLL的主要影响因素,建立的预测公式预测成人最大腰椎前凸具有良好的可靠性与有效性。     

全脊柱成像系统与传统X线在腰椎－骨盆矢状面参数的一致性对比

目的：探讨腰椎-骨盆矢状面参数在全脊柱EOS^®成像系统（whole-spine EOS^® images,EOS）与传统X线成像的一致性。方法：选择2019年5月至7月在北京积水潭医院脊柱外科住院的患者50例（男26例,女24例）,进行标准站立位EOS脊柱全长正侧位和传统X线腰椎骨盆正侧位摄片。2名主治医师分别使用Surgimap软件对50例患者EOS侧位片和传统X线腰椎骨盆侧位片的骨盆入射角（pelvic incidence,PI）,骨盆倾斜角（pelvic tilt,PT）,骶骨倾斜角（sacral slope,SS）,腰椎前凸角（lumbar lodorsis,LL）进行测量,并于间隔2周后在再次测量。对2名医师测量的结果进行一致性检验（可信度分析）,对2名医师前后2次测量结果进行一致性检验（可重复性分析）。利用4次测量数据分析腰椎-骨盆矢状面平衡参数在EOS与传统X线的一致性和差异性。结果：使用EOS成像和传统X线成像测量的PI角均值分别为（50.5±12.6）°和（51.4±12.2）°（均值差0.9,差值95%置信区间为0.2-1.6,P=0.020）;PT角均值分别为（16.2±8.9）°和（16.9±8.6）°（均值差0.7,差值95%置信区间为-0.6-2.0,P=0.283）;SS角均值分别为（34.3±9.9）°和（34.5±10.4）°（均值差0.2,差值95%置信区间为-1.2-1.5,P=0.800）;LL角均值分别为（42.7±14.9）°和（43.3±15.3）°（均值差0.6,差值95%置信区间为-0.8-2.0,P=0.149）。两种不同成像方法测量骨盆PI差异有统计学意义（P=0.020,P<0.05）,但均差值小（0.9°）,无临床差异性;PT、SS、LL差异无统计学意义（P>0.05）。两种成像方法组间可信度分析显示,2名医师使用Surgimap软件测量侧位PI、PT、SS、LL均有极佳的一致性（EOS成像的相关系数分别为0.984、0.993、0.980、0.989,X线成像的相关系数分别为0.975、0.985、0.976、0.988）。可重复性分析显示,2名主治医师前后2次测量的PI、PT、SS、LL均有极佳的一致性（组内ICC为0.963~0.996）。结论：在局部腰椎骨盆段,EOS成像与传统X线成像测量的PI、PT、SS、LL一致性良好,对指导临床的应用没有差异性。     

MR引导聚焦超声治疗子宫腺肌瘤前、后超声造影参数与疗效的相关性

目的 观察MR引导聚焦超声（MRgFUS）治疗子宫腺肌瘤前、后超声造影（CEUS）参数与疗效的相关性。方法 回顾性分析26例接受MRgFUS的子宫腺肌瘤患者治疗前及治疗后24 h、1个月、6个月子宫超声及CEUS,以及治疗前和治疗后即刻MRI;对比治疗前CEUS与MRI所示病灶体积,治疗后即刻MRI与治疗后24 h CEUS所示非灌注体积（NPV）,基于治疗后24 h的CEUS结果计算消融率。观察病灶治疗前、治疗后24 h血流评分及二者之和,以及治疗前、后1及6个月痛经数字评分量表（NRS）评分及其变化率,分析CEUS参数与疗效的相关性。结果 CEUS与MRI所示病灶体积及NPV差异均无统计学意义（P均＞0.05）。治疗后24 h病灶消融率为（58.11±24.92）%。治疗前及治疗后24 h病灶血流评分及二者之和分别为2.00（2.00,2.00）、1.00（1.00,1.00）及3.50（3.00,3.50）,治疗前与治疗后24 h差异有统计学意义（Z=－4.463,P＜0.001）。治疗前、治疗后1及6个月,NRS评分分别为5.00（4.00,6.00）、3.00（2.00,4.00）及2.00（1.00,3.00）,差异均有统计学意义（P均＜0.01）;治疗后1及6个月NRS评分变化率分别为35.42%（23.75%,50.00%）及60.00%（50.00%,77.08%）。治疗前及治疗后24 h病灶血流评分及二者之和均与消融率呈负相关（r_s=－0.552、－0.820、－0.745）,与治疗后6个月NRS评分呈正相关（r_s=0.513、0.552、0.496）而与治疗后6个月NRS评分变化率均呈负相关（r_s=－0.525、－0.479、－0.531）;治疗后24 h病灶消融率与治疗后6个月NRS评分呈负相关（r_s=－0.462）、与治疗后6个月NRS评分变化率呈正相关（r_s=0.500）。结论 MRgFUS治疗子宫腺肌瘤前、后CEUS参数与疗效相关。     

C7倾斜角与脊柱整体矢状面平衡的相关性

目的 探讨腰背痛患者C₇倾斜角（C₇S）与脊柱矢状面参数、脊柱矢状面平衡状态之间的关系。方法 对215例腰背痛患者进行回顾性研究,在术前、术后脊柱全长X线片上测量脊柱矢状面参数,并引入颈胸组合参数“颈椎前凸角（CL）/C₇S”。根据患者术前矢状面平衡状态（矢状面轴向距离,SVA）和胸椎代偿能力（胸椎后凸角,TK）将患者分为3类。类型A,脊柱矢状面平衡（SVA≤5 cm）;类型B,脊柱矢状面失平衡,胸椎具有代偿能力（SVA > 5 cm,TK≤40°）;类型C,脊柱矢状面失平衡,胸椎失代偿（SVA > 5 cm,TK > 40°）。分析C₇S与脊柱矢状面参数之间的相关性,比较3类患者脊柱矢状面参数的差异。结果 C₇S与T₁倾斜角（T₁S）、TK、CL、颈椎SVA（cSVA）、SVA及患者年龄之间均存在相关性（r = 0.305 ~ 0.802,P<0.05）。C₇S的变化与TK的变化有关（r = 0.494,P<0.05）,与SVA及CL的变化均无关。相比于类型A,类型B患者的SVA、CL和CL/C₇S 更大,TK更小,差异均有统计学意义（P<0.05）,cSVA、C₇S差异无统计学意义（P>0.05）;相比于类型A,类型C患者的cSVA、SVA、CL、TK、C₇S和CL/C₇S更大,差异均有统计学意义（P<0.05）;相比于类型B,类型C患者的cSVA、C₇S、CL和TK更大,差异均有统计学意义（P<0.05）,但CL/C₇S和SVA差异无统计学意义（P>0.05）。CL/C₇S评价脊柱矢状面平衡的临界值为0.618。结论 C₇S与脊柱矢状面参数之间存在较好相关性。当CL/C₇S > 0.618时,脊柱更多处于失平衡状态。     

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.     

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.     

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.     

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.