后路腰椎内固定术后手术部位感染的危险因素分析

目的:探讨后路腰椎内固定术后手术部位感染的危险因素,为降低手术部位感染的发生率提供参考依据。方法:回顾我科2016年1月1日～2018年12月31日实施后路腰椎内固定手术的1073例患者,男516例,女557例,年龄18～84岁(54.67±13.23岁),将术后手术部位感染的患者纳入感染组,其余患者纳入非感染组。收集两组患者的性别、年龄、诊断、体重指数(BMI)、合并糖尿病和高血压情况、手术时间、术中出血量、是否输血、吸烟史、术前美国麻醉医师协会(ASA)分级、术前使用激素情况、内固定节段数、是否固定至慨骨或骨盆、是否为翻修手术、手术开始时段等资料,进行单因素分析,对阳性结果进行多因素Logistic回归分析。结果:1073例患者中发生手术部位感染19例,感染发生率为1.77%,其中男11例,女8例,年龄18～77岁(54.89±16.67岁)。单因素分析显示两组肥胖(BMI≥28kg/m~2)、合并糖尿病、手术时间、手术开始时段等因素存在统计学差异(P0.05);性别、年龄、疾病种类、合并高血压、出血量、是否输血、吸烟史、术前ASA分级、术前使用激素、内固定节段数、是否固定至慨骨或骨盆、是否为翻修手术等因素无统计学差异(P0.05)。多因素Logistic回归结果显示肥胖(OR=6.704,P=0.005)、合并糖尿病(OR=4.071,P=0.008)、较长手术时间(OR=7.102,P=0.000)、手术开始时段为晚间(OR=3.981,P=0.018)是术后手术部位感染的独立危险因素。结论:肥胖、合并糖尿病、较长手术时间、手术开始时段为晚间的患者后路腰椎内固定术后发生手术部位感染的风险较高,应采取有针对性的预防措施,以期最大限度降低术后手术部位感染的发生。     

糖尿病患者脊柱后路内固定术后手术部位感染的危险因素:一项多中心研究

[目的]探讨糖尿病患者脊柱后路内固定术后发生手术部位感染的危险因素。[方法]回顾性分析三家医院自2011年1月²013年9月间共322例合并糖尿病的脊柱后路内固定手术患者的临床资料,分为感染组与未感染组,单因素分析对比两组患者在危险因素方面的差异性,并进行Logistic多因素回归分析。[结果]本组322例患者中13例发生手术部位感染,感染率为4.0%。感染组与未感染组单因素分析发现BMI、手术时间、尿蛋白阳性和术前依赖胰岛素等4个指标的差异有统计学意义;多因素回归分析显示,导致手术部位感染的独立危险因素包括BMI(OR=1.867,P=0.032)、尿蛋白阳性(OR=2.978,P=0.001)和手术时间(OR=1.366,P=0.028)。[结论]体重指数、尿蛋白阳性和手术时间是糖尿病患者行脊柱后路内固定术后发生手术部位感染的独立危险因素。     

腰椎后路融合术后急性手术部位感染的危险因素分析

目的探讨腰椎后路融合术后发生急性手术部位感染的相关危险因素。方法回顾性分析2016年1月至2018年12月于我院脊柱外科行腰椎后路融合手术的330例病人的临床资料。病人主要诊断包括腰椎椎管狭窄、腰椎间盘突出症、腰椎骨折、肿瘤等。根据术后是否发生急性手术部位感染将病人分为感染组和非感染组,选择年龄、性别、身体质量指数(body mass index, BMI)、吸烟、高血压、糖尿病、骨质疏松症、手术节段数、手术时间、出血量、切口长度、术后引流时间、尿路感染和脑脊液漏等可能影响术后急性手术部位感染的因素,先后应用单因素分析和二元Logistic回归分析腰椎后路融合术后急性手术部位感染的危险因素。结果共有19例术后发生了急性手术部位感染,发生率为5.76%(19/330)。单因素分析结果显示:两组病人的年龄、BMI、糖尿病、骨质疏松、手术节段、手术时间、出血量、脑脊液漏、尿路感染以及切口长度的差异均有统计学意义(P均<0.05)。二元Logistic回归分析结果显示:BMI[OR=1.429,95%CI(1.059,1.929),P=0.020]、合并糖尿病[OR=9.568,95%CI(2.183,41.935),P=0.003]、手术时间[OR=8.868,95%CI(1.992,39.482),P=0.004]、切口长度[OR=7.257,95%CI(2.937,16.719),P<0.001]为腰椎后路融合术后急性手术部位感染的独立危险因素。结论为了降低腰椎术后急性手术部位感染的发生率,围术期应合理评估控制相关危险因素,以获得更好的治疗效果和病人满意度。     

食管癌术后并发肺部感染的相关因素

目的探讨食管癌患者术后并发肺部感染的相关因素,为临床预防术后肺部感染的发生、提高手术效果提供参考依据。 方法回顾性分析2012至2013年川北医学院附属医院胸外科接受食管癌根治术的215例患者的临床资料,按照术后是否发生肺部感染,将其分为感染组和对照组,其中感染组患者95例,男性73例,女性22例,平均年龄（63.8±7.5）岁;对照组患者120例,男性83例,女性37例,平均年龄（61.7±6.3）岁。利用卡方检验对两组病例的性别、年龄、病变部位、吸烟史、手术持续时间、术后呼吸机辅助呼吸时间及术前并发症进行率的比较,并通过Logistic多因素回归分析方法进一步明确食管癌切除术后并发肺部感染的危险因素。 结果卡方检验结果表明,术后肺感染组患者高龄（≥ 60岁）、肿瘤发生部位、吸烟史（≥ 20年）、手术持续时间（≥ 3 h）、术后呼吸机辅助呼吸时间（≥ 2 h）、术前并发症（糖尿病、COPD Ⅲ级以上、低蛋白血症）的比重均高于对照组（P均<0.05）。Logistic多因素回归分析表明,年龄≥ 60岁（χ² = 4.201、P = 0.04）、烟龄≥ 20年（χ² = 11.204、P = 0.001）、病变部位（χ² = 12.415、P = 0.000）、手术时间≥ 3 h（χ² =4.28、P = 0.045）、术后呼吸机辅助呼吸时间≥ 2 h（χ² = 4.565、P = 0.033）、术前并发糖尿病（χ² = 7.335,P = 0.007）、术前合并低蛋白血症（χ² = 4.97、P = 0.026）及术前合并COPD Ⅲ级以上（χ² = 5.225、P = 0.022）是食管癌术后并发肺部感染的高危因素。 结论年龄≥ 60岁、烟龄≥ 20年、肿瘤发生部位、手术时间≥ 3 h、术后呼吸机辅助呼吸时间≥ 2 h、术前合并糖尿病、低蛋白血症或重度肺功能受损是食管癌切除术后并发肺部感染的高危因素。     

老年脊柱手术患者术后发生谵妄的危险因素分析

[目的]探讨老年脊柱手术患者术后发生谵妄的危险因素。[方法]回顾分析2014年8月～2016年10月在本院行脊柱内固定手术的老年患者(年龄65岁)共846例的临床资料,其中,术后出现谵妄者92例,男58例,女44例,其中颈椎手术38例,腰椎手术54例,而其余745例患者术后无谵妄。比较两组间性别、年龄、体重指数、吸烟史,术前主要内科合并症、手术部位、手术时间、术中失血量、术后是否发生低氧血症以及术后是否使用止痛泵等,寻找谵妄相关危险因素。并应用Logistic回归进行多因素分析。[结果]单因素分析结果显示年龄、术前血红蛋白值、糖尿病史、脑卒中病史、手术时间及术后低氧血症在谵妄组和非谵妄组之间的差异有统计学意义(P0.05)。多因素logistic回归分析表明术前血红蛋白低(OR=2.026,95%CI 1.229～3.338,P=0.006),高血压病史(OR=1.633,95%CI 1.008～2.646,P=0.046)、慢阻肺疾病史(OR=2.222,95%CI 1.147～4.302,P=0.018)、颈椎手术(OR=1.544,95%CI 1.298～1.994,P=0.048)、手术时间长(OR=1.010,95%CI 1.004～1.016,P=0.002)是术后发生谵妄的独立危险因素。[结论]术前血红蛋白低、高血压病史、慢阻肺疾病史、颈椎手术、手术时间长是术后发生谵妄的独立危险因素。     

获得性免疫缺陷综合征合并肺孢子菌性肺炎患者病情影响因素

目的探讨获得性免疫缺陷综合征（AIDS）合并肺孢子菌性肺炎（PCP）患者病情的影响因素。 方法分析2009年1月至2017年9月首都医科大学附属北京地坛医院收治的1 001例AIDS合并PCP患者的临床资料，根据PaO₂将患者分为轻度PCP组（PaO₂ ≥ 70 mmHg）（543例）和中重度PCP组（PaO₂ <70 mmHg）（458例），并采用单因素和多因素Logistic回归方法分析年龄、乳酸脱氢酶（LDH）水平增高、肺部混合感染、低蛋白血症和气胸等因素是否影响AIDS合并PCP患者的病情进展。 结果轻度PCP组和中重度PCP组患者气胸发生率分别为1.1%（6/543）和7.6%（35/458），差异有统计学意义（χ² = 27.027、P < 0.001）；轻度PCP组和中重度PCP组患者肺部混合感染的发生率分别为86.4%（469/543）和95.0%（435/458），差异有统计学意义（χ² = 21.027、P < 0.001）；轻度PCP组和中重度PCP组患者低蛋白血症发生率分别为29.47%（160/543）和42.58%（195/458），差异有统计学意义（χ² = 18.658、P < 0.001）；轻度PCP组和中重度PCP组患者中LDH ≥ 350 U/L者分别为32.04%（174/543）和61.57%（282/458），差异有统计学意义（χ² = 87.338、P < 0.001）。单因素回归分析发现年龄≥ 50岁、LDH ≥ 350 U/L、肺部混合感染、低蛋白血症和气胸等因素在轻度和中重度PCP两组患者间差异均有统计学意义（OR = 0.489、95%CI：0.354～0.676、P < 0.001，OR = 0.294、95%CI：0.227～0.382、P < 0.001，OR = 0.335、95%CI：0.206～0.545、P < 0.001，OR = 0.563、95%CI：0.434～0.732、P < 0.001，OR = 0.135、95%CI：0.056～0.324、P < 0.001）。多因素Logistic回归分析发现，引起AIDS合并PCP患者病情加重的独立风险因素为年龄≥ 50岁（OR = 0.410、95%CI：0.288～0.582，P < 0.001）、肺部混合感染（OR = 0.417、95%CI：0.251～0.692，P < 0.001）、LDH ≥ 350 U/L（OR = 0.298、95%CI：0.227～0.392，P < 0.001）、低蛋白血症（OR = 0.685、95%CI：0.516～0.908，P = 0.009）和气胸（OR = 0.172、95%CI：0.070～0.424，P < 0.001）。 结论年龄≥ 50岁、肺部混合感染、LDH水平过高（≥ 350 U/L）、低蛋白血症和气胸等风险因素均可导致AIDS合并PCP患者病情加重，对相关风险因素进行积极干预可减缓患者疾病进展。     

脊柱结核术后手术部位感染的相关危险因素分析

【摘要】 目的：探讨脊柱结核术后手术部位感染的危险因素,总结预防策略并为临床治疗提供参考。方法：回顾性分析2018年1月~2020年1月于我院实施手术治疗的脊柱结核患者161例。其中男性101例,女性60例,年龄46.9±17.9岁。发生术后手术部位感染10例,感染发生率为6.21%。术后手术部位感染患者中男性5例,女性5例;病原学培养结果：金黄色葡萄球菌4例,铜绿假单胞菌3例,阴沟肠杆菌2例、鲍曼不动杆菌1例。记录患者相关因素信息包括：年龄是否＞60岁、性别、血清白蛋白浓度是否＜30g/L、血沉是否≥20mm/h、体质指数（body mass index,BMI）是否<18.5kg/m2、患者是否患有糖尿病、术后72h峰值血糖值是否≥11.1mmol/L、患者是否有吸烟史、是否合并脊髓损伤、病灶部位（颈段、胸段、胸腰段或腰段）及范围（病灶范围是否＜3个节段）、是否存在后凸畸形、患者是否存在寒性脓肿,手术相关因素包括：是否使用脉冲式冲洗枪、是否使用内固定、是否进行前柱重建、手术时间是否<300min、是否有术中输血、术中是否局部使用链霉素及手术入路为前入路或后入路等内容。采用SPSS 23.0软件进行统计分析,用非条件Logistic回归法进行多因素分析。结果：单因素分析结果显示,血清蛋白浓度＜30g/L（感染率16.7%）、血沉≥20mm/h（感染率14.0%）、BMI＜18.5kg/m2（感染率16.7%）、患有糖尿病（感染率15.2%）、峰值血糖≥11.1mmol/L（感染率24%）、合并寒性脓肿（感染率3.0%）等患者相关因素是脊柱结核术后手术部位感染的危险因素（P<0.05）,手术时间长（≥300min）（感染率12.7%）、术中进行了输血（感染率10.9%）、局部未使用链霉素（感染率15.8%）等手术相关因素是脊柱结核术后手术部位感染的危险因素（P<0.05）,而年龄、性别、是否有吸烟史、是否合并脊髓损伤、病灶部位、范围、是否存在后凸畸形等患者相关因素不是脊柱结核术后手术部位感染的危险因素（P>0.05）,是否使用脉冲式冲洗枪、是否使用内固定、是否进行前柱重建及手术入路为前入路或后入路等手术相关因素不是脊柱结核术后手术部位感染的危险因素（P>0.05）。多因素Logistic回归分析显示,血清蛋白浓度＜30g/L、峰值血糖≥11.1mmol/L、合并寒性脓肿是脊柱结核术后手术部位感染的独立危险因素（P<0.05）,术中局部使用链霉素作为一项保护因素,可有效预防脊柱结核术后手术部位感染。结论：脊柱结核术前应尽量调整患者营养状态,积极控制血糖,纠正低蛋白血症;术中链霉素对术区感染病灶的局部应用以及寒性脓肿病灶的彻底清除都可以有效降低患者术后手术部位感染的发生。     

脊柱手术患者术后谵妄的危险因素分析

目的 探讨脊柱手术患者术后谵妄（POD）的危险因素,并建立脊柱手术患者POD的风险预测模型。
方法 回顾性收集行脊柱手术患者1 075例,男570例,女505例,年龄≥18岁,BMI 18～35 kg/m²,ASA Ⅰ—Ⅲ级。采用意识模糊评估法-中文修订版（CAM-CR）量表进行评估,根据是否发生POD将患者分为两组：POD组和非POD组。采用单因素分析筛选POD的相关因素,将P＜0.1的相关因素纳入二元Logistic回归模型,分析脊柱手术患者POD的独立危险因素并建立预测模型。绘制受试者工作特征（ROC）曲线并计算ROC曲线下面积（AUC）评价预测模型的价值。
结果 有84例（7.81%）患者发生POD。与非POD组比较,POD组年龄明显增大（P＜0.05）,ASA分级＞Ⅱ级、METs＜4比例明显升高（P＜0.05）,手术侵入类型级别明显升高（P＜0.05）,BIS监测比例明显降低（P＜0.05）,竖脊肌平面阻滞联合全凭静脉麻醉比例明显降低、静-吸复合麻醉和全凭静脉麻醉比例明显升高、出血量明显增加、术后Hb及术后钠离子浓度明显降低、术后第1天VAS疼痛评分明显升高（P＜0.05）。二元Logistic回归分析结果显示,年龄＞60岁（OR=1.099,95%CI 1.062～1.136）、酗酒史（OR=3.427,95%CI 1.859～6.315）、4级手术（OR=25.542,95%CI 1.878～347.342）、出血量＞431 ml（OR=1.005,95%CI 1.002～1.007）、术后第1天VAS疼痛评分＞2分（OR=1.797,95%CI 1.389～2.325）是脊柱手术患者POD的危险因素,BIS监测（OR=0.310,95%CI 0.144～0.669）、竖脊肌平面阻滞联合全凭静脉麻醉（OR=0.138,95%CI 0.051～0.373）、术后Hb＞122.8 g/L（OR=0.966,95%CI 0.943～0.993）是脊柱手术患者POD的保护因素。预测模型为Logit（P）=0.094×年龄+1.232×酗酒史-0.035×术后Hb+3.240×4级手术-1.171×BIS监测-1.980×竖脊肌平面阻滞联合全凭静脉麻醉+0.005×出血量+0.586×术后第1天VAS疼痛评分-9.648,该模型AUC为0.933（95%CI 0.917～0.948,P<0.001）,敏感性为90.5%,特异性为82.1%。
结论 年龄＞60岁、酗酒史、手术侵入类型（4级手术）、出血量＞431 ml以及术后第1天VAS疼痛评分＞2分是脊柱手术患者POD的独立危险因素。     

人工全髋关节置换术后早期手术部位感染的危险因素分析

目的探讨人工全髋关节置换术（THA）后早期手术部位感染的危险因素。方法回顾分析2000年1月至2010年10月本组所行153例单侧THA的患者,其中男46例,女107例,年龄29～79岁,平均（61．0±8．9）岁。回顾性分析多项临床因素与手术部位感染的相关性。连续变量包括：年龄、手术时间、手术出血量、术前白蛋白血清浓度、伤口引流管停留时间;分类变量包括：性别、有无长期使用激素病史、是否合并糖尿病、有无前次手术史、是否使用骨水泥、预防性抗生素使用方案。153例患者按照是否发生手术部位感染分成两组,对连续变量采用f检验、分类变量采用√检验进行比较。结果153例患者中8例出现手术部位感染,发生率为5．23％。单因素分析发现术前白蛋白血清浓度因素差异有统计学意义（t=2．752,P〈0．05）;白蛋白〈35g／L与白蛋白〉35g／L比较差异有统计学意义（岔=7．23,P〈0．05）。有无长期口服激素、有无前次手术比较差异有统计学意义（其Х^2值分别为3．93与12．38,P〈0．05）。年龄、性别、手术时间、术中出血量、抗生素使用时间、引流管停留时间、是否合并糖尿病、是否使用骨水泥等因素对手术部位感染发生无影响,均无统计学差异。结论THA术前低蛋白血症、前次手术史、长期口服激素史是手术部位感染的高危因素。     

重度颅脑外伤合并肺部感染的危险因素

目的探讨重度颅脑外伤合并肺部感染的危险因素,并提出相对应的处理措施,以提高对该病的临床治疗水平。 方法回顾性分析2011年1月至2014年1月收集的90例重度颅脑外伤患者,对其中29例合并肺部感染者进行危险因素分析。 结果重度颅脑外伤合并肺部感染相关因素有：高龄（> 60岁）、呼吸机应用、休克、气管切开、基础疾病、肺部原有疾病、低蛋白血症、抗菌药物和激素应用以及GCS评分等（P均< 0.05）。而与患者性别和手术史无关（P均> 0.05）。年龄（OR = 6.852）、GCS评分（OR = 7.483）、基础疾病（OR = 8.852）、气管切开（OR = 5.597）、抗菌药物（OR = 8.849）和激素的应用（OR = 8.674）以及休克（OR = 5.832）是重度颅脑外伤合并肺部感染高危险因素。 结论充分做好入院相关准备且进行积极预防,可降低重度颅脑外伤合并肺部感染的发生。     

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.