基于SEER数据库的胃癌肝转移预后因素分析与预后模型构建

背景与目的：胃癌其因具有恶性程度高、易早期转移等特点而导致患者往往具有较差的临床预后,其中胃癌肝转移（GCLM）更是导致患者死亡的主要因素,然而,目前对于GCLM的预后评价手段仍然存在着一定的不足。因此,本研究利用SEER数据库分析GCLM患者的临床病理特征和预后风险因素,从而建立具有良好预测能力的评估模型,以提升对患者个体化预后的评估能力。 方法：从SEER数据库中提取2010—2015年确诊的GCLM患者的临床资料。根据纳入和排除标准,严格筛选后纳入研究病例共2 554例,按7:3比例随机分配为建模集（1 790例）和验证集（764例）,比较建模集与验证集中患者的临床基线特征差异,用Cox等比例回归模型与Fine-Gray竞争风险模型分别筛选出GCLM患者总体生存期（OS）与癌症特异性生存期（CSS）的独立危险因素。基于建模集Cox或Fine-Gray风险模型的多元回归分析及AIC因素优化的结果,构建预测GCLM患者OS或CSS的列线图模型。最后,采用一致性指数、ROC曲线和校正曲线评估模型预测的可靠性。 结果： 建模集与验证集患者的基线特征无明显差异。分析结果显示,患者年龄、化疗、肿瘤分级、原发灶切除和原发灶数目是影响GCLM患者OS预后的独立危险因素,而化疗、肿瘤分级、原发灶切除和原发灶数目是影响GCLM患者CSS预后的独立危险因素（均P<0.05）。基于上述指标分别构建列线图模型并进行评价,预测OS与CSS列线图模型的一致性指数均明显高于AJCC-TNM分期系统（建模集：0.706 vs. 0.560、0.670 vs. 0.554;验证集：0.769 vs. 0.534、0.744 vs. 0.518）,并且ROC曲线分析亦展示出预测模型具有较高的准确度。最后,校正曲线分析显示,构建的列线图模型预测患者OS或CSS的生存率与实际观察值均具有良好的一致性。 结论： 基于SEER数据库分析构建的列线图模型在预测GCLM患者OS和CSS方面有较高的准确性,将有助于临床医师对GCLM患者制定个体化的治疗策略。     

胆囊鳞状细胞癌预后模型的构建与验证

背景与目的 胆囊鳞状细胞癌（GSCC）是胆囊癌中一种罕见的病理学类型,占胆囊癌的1%~4%。该类型肿瘤预后差,目前关于GSCC的文献报道主要是个案报道和小样本系列病例报道,由于缺乏大样本高质量的临床研究证据,目前临床上尚无针对GSCC的治疗指南、共识和个体化的预后评价工具。因此,本研究通过SEER数据库中的大样本数据构建GSCC患者预后列线图,旨在精准化、个体化评价GSCC患者的预后,为临床决策制定提供参考。方法 提取SEER 数据库中2000—2019年期间经病理确诊的GSCC患者的临床资料,按照7∶3的比例,将数据随机划分为训练集和验证集,在训练集中,分别采用多变量Cox比例风险模型和LASSO回归筛选影响GSCC患者预后的独立因素,利用这些因素,构建用于预测GSCC患者在3个月和6个月的肿瘤特异性生存期（CSS）和总生存期（OS）的列线图模型。随后,在训练集中,利用一致性指数（C指数）、ROC曲线和校准曲线,分别在训练集和验证集,对模型进行内部和外部验证,以评估模型的准确度和预测能力。结果 本研究共纳入257例患者,其中训练集179例,验证集78例。在训练集和验证集中,患者的中位随访时间分别为3（1~7）个月和4（2~8）个月。两组之间基线资料均衡可比。多变量Cox比例风险模型分析显示,年龄、SEER分期、手术和化疗是GSCC患者OS和CSS的独立影响因素（均P<0.05）。LASSO回归分析显示,年龄、SEER分期、放疗、手术和化疗与GSCC患者的OS相关;年龄、SEER分期、手术和化疗与GSCC患者的CSS相关。基于这些独立预后影响因素,构建了用于预测GSCC患者在3、6个月的OS和CSS的列线图。对模型的验证结果表明,训练集和验证集中,OS的C指数分别为0.739（95% CI=0.700~0.780）和0.729（95% CI=0.660~0.800）;CSS的C指数分别为0.750（95% CI=0.710~0.790）和0.741（95% CI=0.670~0.810）。ROC曲线分析显示,曲线在训练集和验证集的AUC值均>0.8;校准曲线分析表明,通过模型预测的3、6个月的OS和CSS与GSCC患者真实的3、6个月的OS和CSS有较好的重合,两者均靠近理想的45°参考线,表现出良好的一致性。结论 年龄、SEER分期、手术、放疗和化疗是GSCC患者预后的独立影响因素。所构建的列线图预测模型具有良好的预测价值,有利于临床对GSCC患者选择个性化治疗。     

胃癌患者预后相关影响因素的列线图模型构建及验证

背景与目的 中国胃癌疾病负担较重且预后影响因素较多,有关量化和综合评估预后风险的研究较少。因此,本研究基于列线图探究炎症指标中性粒细胞/淋巴细胞比率（NLR）和血小板/淋巴细胞比率（PLR）对胃癌患者预后生存的意义,并将其纳入列线图与传统TNM分期进行预后评估效能比较。方法 回顾性纳入2013年6月—2018年6月在中国科学技术大学第一附属医院胃肠外科接受胃癌根治切除术的胃癌患者作为训练组（n=300）,同时从胃肠外科另一病区纳入接受相同手术处理的胃癌患者作为验证组（n=100）。通过医院电子病历系统采集患者的年龄、性别、肿瘤类型、肿瘤部位、侵袭深度和淋巴结转移（LNM）等信息;术前3 d收集外周静脉血数据,并计算NLR和PLR,通过ROC曲线确定NLR（1.98）和PLR（134.87）的最佳临界点。术后2年内每3个月随访1次,2年后每6个月随访1次。采用Cox比例风险模型计算暴露与结局指标的关联,根据多因素分析结果识别影响胃癌预后的独立风险因素,纳入列线图后通过C-指数在训练组和验证组评估列线图的稳定性。最后,基于ROC曲线下面积（AUC）比较列线图和传统TNM分期的预测效能。结果 训练组男性患者220例（73.3%）,验证组男性患者69例（69.0%）,训练组平均年龄（62.52±10.61）岁,验证组平均年龄（63.67±10.21）岁。两组除肿瘤类型、分化程度和侵袭深度外,其他基线特征差异无统计学意义;训练组中位生存时间（OS）为28个月,1、3、5年OS率分别为63.5%、43.0%和35.1%;验证组中位OS为32个月,1、3、5年OS率分别为58.9%、41.6%和31.7%。单因素Cox回归分析显示,年龄、病理分型、肿瘤分化程度、侵袭深度、存在LNM、NLR、PLR和CEA水平均与OS有关（均P<0.05）。经过多因素调整后,存在LNM、术前NLR>1.98、PLR>134.87和癌胚抗原（CEA）≥5 μg/L的患者OS显著缩短（均P<0.01）。校准曲线结果显示列线图模型在训练组（C-指数=0.81）和验证组（C-指数=0.75）的拟合度良好。此外,列线图模型预测训练组1、3、5年OS率的AUC值（0.865,0.855,0.827）高于TNM分期（0.677,0.690,0.683）;验证组1、3、5年OS率的AUC值（0.856,0.788,0.725）高于TNM分期（0.781,0.691,0.605）。结论 NLR和PLR是预测胃癌患者术后生存的独立风险因素,基于两者构建的列线图可以较为准确地预测行胃切除术胃癌患者的1、3、5年OS率,为临床医师提供更精确的治疗、护理决策证据。     

胰腺癌患者预后预测动态在线列线图的构建及应用

背景与目的 胰腺癌具有高度侵袭性,患者的预后很差,与其他癌症不同,在过去的几年中,胰腺癌的发病率继续增加,存活率几乎没有提高。目前临床上使用的TNM分期系统来评估患者预后指标较为单一。因此,本研究的目的是构建一个动态的在线列线图,用于预测胰腺癌患者预后,为临床个体化治疗提供参考。方法 从SEER数据库中提取了2000—2018年病理确诊为胰腺癌的患者信息,并按7∶3的比例随机分为训练队列与验证队列。采用单因素和多因素的Cox回归分析来确定预后风险因素,并使用R软件构建动态在线列线图。使用C-指数、与时间相关ROC曲线的曲线下面积（AUC）、校准曲线和决策曲线分析（DCA）来评估列线图的临床效用。根据列线图再将患者分为高风险组和低风险组,通过Kaplan-Meier生存曲线比较两组患者的预后。结果 共在SEER数据库中筛选出12 175例胰腺癌患者,年龄、肿瘤分化程度、原发部位、T分期、N分期、M分期、手术、化疗和肿瘤大小是总生存期（OS）的独立影响因素（均P<0.05）。在训练队列中,与OS相关列线图的C-指数为0.759（95% CI=0.745~0.772）,预测1、3、5年OS的AUC分别为0.828、0.842和0.849。在验证队列中,C-指数为0.756（95% CI=0.735~0.776）,1、3、5年OS的AUC分别为0.820、0.831和0.842。校准图和DCA曲线显示了该模型在训练和验证队列中有良好预测性能。Kaplan-Meier生存曲线显示,在验证集和训练集中,低风险组患者的总OS优于高风险组（均P<0.05）。结论 建立的动态在线列线图有良好预测性能,有助于个性化结合临床患者实际情况综合预测胰腺癌患者的预后,并可能比TNM分期系统具有更好的临床应用价值。     

甲状腺髓样癌术后生存影响因素分析及列线图的构建

背景与目的 目前用于评估甲状腺髓样癌（MTC）预后的主要方式采用TNM分期系统，但该系统不能个体化预测患者的预后。因此，需要建立专门针对MTC的精准预后指标体系。本研究分析影响MTC患者术后生存的因素，并构建MTC术后生存列线图。方法 选取2004—2015年SEER数据库MTC数据，共筛选出符合条件的1 884例患者纳入研究。将患者按3∶1随机分为训练集（1 413例）和验证集（471例），比较两组临床数据基线特征差异。采用单因素和多因素Cox回归模型筛选影响MTC生存的独立因素，Kaplan-Meier生存曲线分析其对预后的影响。基于Cox回归分析筛选出的结果建立MTC术后患者生存列线图。通过一致性指数（C-index）、ROC曲线、曲线下面积（AUC）、校准曲线和决策曲线分析（DCA）对列线图进行验证和评估。结果 单因素分析结果显示，性别、年龄、原发肿瘤分期、淋巴结转移、远处转移、是否甲状腺全切除、肿瘤是否侵犯甲状腺被膜、是否行放射治疗均影响患者预后（均P<0.05）；Cox回归分析结果显示，性别、年龄、远处转移、侵犯甲状腺被膜、是否行甲状腺全切除术、是否放疗为MTC患者的独立预后因素（均P<0.05）。Kaplan-Meier生存曲线显示，男性患者、年龄≥49岁、伴远处转移、肿瘤侵犯甲状腺被膜、未行甲状腺全切除术、接收放疗患者预后更差。用患者性别、年龄、远处转移、甲状腺被膜受侵、手术方式构建了MTC患者2、5、10年的生存列线图。该列线图训练集的C-index为0.755（95% CI=0.741~0.769），验证集为0.725（95% CI=0.699~0.769）。ROC曲线用于评估列线图的区分度，在训练集2、5、10年的AUC值分别为0.79、0.779、0.766；在验证集分别为0.78、0.725、0.733。校准曲线结果显示该列线图预测的生存率和实际生存率具有一致性。DCA将列线图与AJCC第6版TNM分期的临床相比，该列线图的在5年和10年生存评估中均显示出更大的净收益。结论 性别、年龄、远处转移、甲状腺被膜侵犯、手术方式是影响MTC患者生存的独立因素；MTC术后生存列线图模型在一定程度上能够更准确地进行患者个体生存预测，帮助临床医师做出适当的个体化临床决策。     

肝细胞癌微血管侵犯危险因素分析及术前预测列线图模型构建

背景与目的 术前有效预测微血管侵犯（MVI）对肝细胞癌（HCC）患者的临床决策、术后辅助治疗和全面的预后评估具有重要的临床价值。因此,本研究探讨HCC合MVI的危险因素并建立术前风险预测列线图模型,以期为临床提供参考。方法 回顾分析2017年1月—2020年11月安徽省立医院收治的535例HCC患者临床资料,将患者按入院时间分为模型组（433例）,验证组（102例）。进行单因素和多因素分析,以确定MVI的独立危险因素,应用R软件建立预测术前HCC的MVI风险的列线图模型,用Bootstrap法进行模型的内部验证,用验证组进行模型的外部验证,采用一致性指数、较正曲线及受试者工作特征（ROC）曲线来评估列线图的预测价值。结果 模型组多因素分析显示,NLR>2.282（OR=1.864,95% CI=1.184~2.933）、GGT>60 IU/L（OR=2.554,95% CI=1.631~4.001）、lgAFP（OR=1.455,95% CI=1.21~1.75）、肿瘤大小（OR=1.177,95% CI=1.084~1.277）、无完整假包膜（OR=2.019,95% CI=1.286~3.171）是术前预测HCC患者MVI的独立危险因素,并以此建立的列线图模型一致性指数在模型组和验证组为分别为0.785（95% CI=0.742~0.828）、0.824（95% CI=0.737~0.91）。模型与校准预测曲线贴合良好,通过Youden指数计算出列线图的最佳临界值为103分,临界值下的敏感度、特异度、阳性预测值和阴性预测值在模型组分别为86%、61%、67%和82%,在验证组中分别为82%、56%、53%和83%。结论 NLR>2.282、GGT>60 IU/L、lgAFP、肿瘤大小、无完整假包膜是HCC发生MVI的独立影响因素,以此建立的列线图模型术前预测MVI效能良好,可直观的分析术前合并微血管侵犯的发生风险,甄别出高风险人群。     

建立临床-影像学联合列线图模型早期识别TACE抵抗肝细胞癌

目的 建立预测TACE抵抗肝细胞癌(HCC)的临床-影像学联合列线图模型,评价其早期识别TACE抵抗HCC的价值。方法 回顾性分析218例接受TACE的HCC患者临床资料,以其中137例作为训练集,81例作为验证集。采用Cox风险回归模型,基于训练集临床及影像学资料筛选预测TACE抵抗HCC的独立因素;建立列线图模型,评价其判断训练集与验证集中TACE抵抗低、高危HCC患者中位总生存期(OS)的差异;并以校准曲线及决策曲线验证列线图模型的校准度及临床价值。结果 回归分析显示巴塞罗那临床肝癌(BCLC)分期、肿瘤最大径、边界及病灶数目是影响HCC患者中位OS的独立因素。列线图模型判断的训练集及验证集TACE抵抗低、高危HCC患者中位OS差异均有统计学意义(P均＜0.05)。校准曲线及决策曲线显示临床-影像学联合列线图模型校准度良好,可使患者净获益。结论 临床-影像学联合列线图预测模型可用于早期判别TACE抵抗HCC。     

基于SEER数据库的弥漫型胃癌患者预后列线图模型构建及验证

目的：筛选弥漫型胃癌患者预后因素并构建预后列线图，并验证其预测准确性。方法 ：从SEER数据库收集2006—2018年病理诊断为弥漫型胃癌的2877例患者的临床病理特征，随机将患者分为训练队列（1439例）和验证队列（1438例）。利用单因素Log-rank及多因素COX分析筛选出独立预后因素并构建预后列线图，预测1、3、5年的总生存期（OS），使用一致性指数和校准曲线确定列线图预测的准确性和判别能力。结果：年龄、T、N、M、TNM、手术状态、化疗状态7个指标均是OS的独立预后因素（P<0.05），基于独立预后因素构建了1、3、5年OS的列线图。训练队列中列线图的c-指数为0.750(95%CI:0.734～0.766)，高于TNM分期系统0.658(95%CI:0.639～0.677)；验证队列列线图的c-指数为0.753(95%CI:0.737～0.769)，高于TNM分期系统0.679(95%CI:0.503～0.697)。校准曲线表明了列线图预测生存率与实际生存率具有良好的一致性。结论：预后列线图能够准确预测弥漫性胃癌患者预后，有助于临床医师对弥漫型胃癌患者进行个体化的预...     

基于SEER数据库男性乳腺癌手术切除病人预后分析及列线图建立

目的 分析男性乳腺浸润性导管癌手术切除病人的独立预后因素及构建预后列线图，同时验证该模型的准确性。方法 从美国国立癌症研究监测、流行病学和最终结果（SEER）数据库中下载2010—2018年间诊断为男性乳腺浸润性导管癌且经过手术切除的1662例病人的临床病理特征及治疗信息。随机数字分组法将病人按照3∶1分为训练队列（1246例）和验证队列（416例）。 通过单因素及多因素 COX分析筛选出独立预后因素并构建预测1、3、5年的总生存率（OS）的列线图。一致性指数（c-指数）和校准曲线确定列线图预测的准确性和判别能力。结果 年龄、肿瘤直径、临床TNM、病理学分级、婚姻状态5个指标均是OS的独立预后因素（P均<0.05）。基于独立预后因素构建了1、3、5年OS的列线图。训练队列中列线图的c-指数为0.730（95%CI 0.694-0.766），高于美国癌症联合委员会（AJCC）临床TNM分期系统 0.628（95%CI 0.588-0.668）；验证队列列线图的c-指数为0.737（95%CI 0.680-0.794），高于AJCC 临床TNM分期系统 0.584（95%CI 0.516-0.652）。校准曲线表明列线图预测生存率与实际生存率具有良好的一致性。结论 基于年龄、肿瘤直径、临床TNM、病理学分级、婚姻状态的独立预后因素构建的列线图能较准确地显示男性乳腺癌手术切除病人预后，有利于进行临床个体化预后评估。     

老年患者肺癌根治术后谵妄的危险因素及列线图预测模型的建立

目的 探讨老年患者肺癌根治术后谵妄（POD）的危险因素,并在此基础上构建与验证预测POD发生风险的列线图模型。
方法 选择择期全麻下行肺癌根治术老年患者580例,男349例,女231例,年龄≥65岁,ASA Ⅰ—Ⅲ级。根据术后3 d内是否发生POD将患者分为两组：POD组与非POD组。通过Lasso回归筛选与POD发生相关的临床变量,并采用多因素Logistic回归分析确定独立危险因素,以此建立预测POD发生风险的列线图模型。分别通过C-index、校准曲线和受试者工作特征（ROC）曲线验证模型的区分度、一致性和准确性,并采用决策曲线分析（DCA）确定模型的临床实用性。
结果 有46例（7.93％）患者发生POD。多因素Logistic回归分析显示,年龄≥75岁、术前简易精神状态量表（MMSE）评分≤25分、术前预后营养指数（PNI）＜45、查尔森合并症指数（CCI）评分≥2分、鳞癌、术中低血压和手术时间≥3 h为POD的独立危险因素。以此构建的列线图模型经内部验证,该模型的C-index为0.864（95％CI 0.811～0.917）;校准曲线显示,该模型预测POD发生风险与实际POD发生风险平均绝对误差为0.038;ROC曲线显示,该模型预测POD发生风险的曲线下面积为0.866（95％CI 0.835～0.892）,敏感性86.96％,特异性73.78％;DCA分析显示该模型具有较好的临床实用性。
结论 年龄≥75岁、术前MMSE评分≤25分、PNI＜45、CCI评分≥2分、鳞癌、术中低血压和手术时间≥3 h是肺癌根治术老年患者POD的独立危险因素,依此构建的列线图模型对POD发生风险具有良好的预测效能。     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

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

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

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

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

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

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

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

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

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

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

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

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

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

Membranes in Artificial Organs

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

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

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

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.