血管分支血液对流换热分析

为分析血液与周围组织换热情况,建立符合循环系统实际结构的血管树分支模型.通过用有限元方法数值求解定壁温条件下分支结构中血液的流动、传热耦合方程,得出血液的速度场、温度场和努赛尔数;并利用该模型,分析半径比、分支角、血管半径、血液流速对分支血管截面平均努赛尔数的影响.结果表明:分支血管入口处速度场和温度场均为非轴对称分布;分支血管人口段的努赛尔数明显小于单个直管的努赛尔数,分支血管努赛尔数收敛值约为3.75;分支角越小、半径比越小、分支血管半径越大、分支血管流速越大时,人口段截面的平均努赛尔数越大;分支血管半径、流速越小,截面平均努赛尔数的收敛速度越快.计算血液与组织换热,需要考虑血管分支的影响.     

高血压时冠状动脉小动脉及微动脉病变的临床特点

高血压对冠状循环的影响涉及到冠状动脉的各级血管 ,包括心外膜冠状动脉 (直径 2～ 7.5ｍｍ)及其主要分支 ( 1～ 2ｍｍ) ,冠状动脉小动脉 ( 50 0～ 1 0 0 0 μｍ)、微动脉 ( <50 0 μｍ)和心肌组织毛细血管 (平均 8μｍ)。其中 ,冠状动脉主干及其主要分支血管的内弹性膜和中膜平滑肌发达 ,具有较强的收缩力 ,能使管腔明显地缩小或扩大 ,从而调节和分配到心脏各部位的血流。而小动脉和微动脉 (亦称外周阻力血管 )仍属肌性动脉 ,其收缩和扩张可显著影响心肌血流量和冠状动脉阻力的变化 ,其中 <30 0 μｍ的微动脉网是冠状动脉主要的阻力血管床…     

腹主动脉杈处的形态观察及力学分析

对87例尸体腹主动脉权的形态进行标定,拍照,通过MYPAD-A_3 K_(510)数字化仪及IBM PC/XT计算机进行参数统计、分析。结果为:①左、右髂总动脉口径无性别、年龄差异;③腹主——髂总动脉分权角左侧大于右侧;③左、右支分支角与相应侧腹主——髂总动脉密切圆半径呈负相关。本文从流体力学角度阐明血管形态与流体间关系,并探讨腹主动脉瘤形成的力学机理。     

红细胞变形性与微循环

红细胞变形性与微循环第四军医大学放射医学教研室（西安７１００３２）吴宛器官灌流量的主要决定因素是血压／血流阻力比率，而血流阻力由血液流变特性（粘滞性）和血管几何特征所左右。决定血液粘滞性的主要因素是红细胞比积、血浆粘度、血细胞聚集性和变形性（主要是红...     

分支血管直径对颅内动脉瘤置入血流导向装置后血流动力学参数的影响

目的综合考虑血流导向装置(flow diverter,FD)置入对动脉瘤瘤体及分支血管的影响,为临床制定更加合理的FD栓塞颅内动脉瘤手术策略提供参考。方法基于计算流体动力学(computational fluid dynamics,CFD)方法,创新应用多孔介质模型模拟FD栓塞颅内分叉动脉瘤的过程。分析和比较不同分支血管直径条件下FD置入动脉瘤前后瘤体与分支血管血液流场、血流速度、壁面压力、壁面剪切力(wall shear stress,WSS)等血流动力学参数的变化。结果 FD置入改变动脉瘤内的血流动力学特征,血流速度减小,动脉瘤壁尤其是顶部压力减小,瘤颈口WSS增大,但瘤颈远侧端与近侧端WSS的差异减小。且不同分支血管直径对血流动力学特征改变的影响程度不同,直径越大,FD置入后流入分支血管内血流的减少量越大,但瘤体内血液流速与瘤顶压力的减少量越小,同时瘤颈部WSS增加量越小。结论分支血管直径越大,FD对动脉瘤的栓塞治疗效果与对血管粥样硬化的改善作用越差,越易造成分支闭塞或其他缺血性并发症的发生。此类情况下进行FD介入栓塞术尤其需要引起临床医师注意。     

高血压病患者眼底血管造影定量分析与血液流变学的关系

对高血压病不同时期患者共80例进行了眼底视网膜荧光血管造影定量分析和血液流变学检查。结果显示：随着高血压分期级别的增加，眼底血管造影定量指标：动脉显影时间、静脉充盈时间、毛细血管交换时间增加．毛细血管密度减少，血液流变学指标：全血比粘度、血球压积、红细胞电泳时间、红细胞聚集指数、全血还原比粘度也增加，并且血管造影定量值与血液流变学指标有显著相关性（r＝0．312～0．626P＜0．05和0．01）。提示高血压靶器官损害下不但表现在微血管血液动力学方面，而且血液流变学也有改变，它们共同造成靶器官损害。     

大鼠主要皮动脉的形态计量学及其相互关系

目的 探讨大鼠主要皮动脉的形态计量学特征及其血流动力学特点. 方法 SD大鼠12只, 行一次性全身血管造影并配合利用Photoshop 与Scion Image等电脑图像处理技术,分析不同类型皮动脉的供血范围、血管密度变化趋势及其供血趋向性等. 结果 6个主要皮动脉的平均外径为(0.53±0.12)mm,其营养体区周长为(18.74±4.84)cm,平均血管密度为(391.31±76.58)灰度/(像素·厘米厚度);皮动脉外径与其营养体区周长呈正相关,其回归方程为:y=32.441x+1.233(r=0.851,n=54,P<0.01). 结论 大鼠皮动脉外径和其营养区域的周长成正比,相同外径的皮动脉,其营养区域的周长相等,区域形状越接近于圆其面积越大.轴型血管营养皮瓣的平均血管密度高于分支型血管.     

T型分叉血管中血液流动对动脉血栓形成的影响

目的 从血流动力学角度研究T型血管分叉处血液流动的改变对血栓形成的影响。主要从血流速度、分支直径、T型分叉角度及血液粘度方面研究血液流动对血栓形成的影响。同时结合相关医学病例,从多学科角度分析并验证医学研究中的有关血栓形成机理的猜测。方法 建立T-型动脉血管的几何模型,采用计算流体动力学方法对血管内流场进行数值分析研究,分析不同条件的流动对血栓形成影响。结果 在分叉血管附近的支血管和主血管中分别形成了两处较大区域的涡流区域,另外,在分叉交接处的下游位置也出现了一处较小的区域,这些区域速度较低,剪应力出现突然增大趋势,符合血栓形成,因此成为“最适成栓位置”。结论 血栓在“最适成栓位置”的形成还与分支血管直径、血管中血流速度、分叉角度以及血液粘度等有密切关系。     

锥度角对非定常的动脉血流的压力分布的影响

应用Navier-Stokes方程和质量连续原理对具有锥度角的动脉血管中非定常状态下的血液发展流动建立了一组数学模型，采用贝塞尔函数方法进行了解析求解，获得了非定常状态下的动脉血液发展流动的速度分布和压力分布公式。并与定常状态下动脉血管中的血液发展流动做了比较。结果表明，非定常状态下动脉血液发展流动的压力分布和定常状态下的动脉血管中的血液发展流动的压力分布差别很大。     

低能量He-Ne激光血管内照射与急性脑血管病微循环、血液流变学研究

通过对60例急性脑血管病患者使用低能量He－Ne激光血管内照射治疗，发现其甲襞微循环治疗前后有明显改变。即治疗后管襻数增多管襻畸形减少，血流速度增快。其血液流变学改变表现为治疗前全血病切变率粘度为5．91±1．68，治疗后降为4．88±1．04，P＜0．001。说明红细胞变形能力显著提高，红细胞聚集性显著降低。故低能量He－Ne激光血管内照射这一方法对治疗急性脑血管病有一定的临床意义。     

D-Lactate concentrations in blood,urine and sweat before and after exercise

Summary The purpose of this study was to investigate changes in the concentrations of D-lactate, L-lactate, pyruvate and methylglyoxal (MG) in body fluids after exercise. Eight untrained male students and five male students who were boat club members engaged in the exercise. Each subject performed runs of short and long duration. Compared to pre-exercise values plasma concentrations of D-lactate, L-lactate and pyruvate increased after running; in trained men by 3.6, 5.0, 3.4 times after short runs and by 1.5, 4.6, 2.0 times after long runs, and in untrained men by 3.0, 12.0, 1.6 times after short runs and 2.5, 5.6, 1.6 times after long runs, respectively. In all cases, the increase of L-lactate was always higher than that of D-lactate after running. The MG contents in red blood cells decreased markedly after running, especially in the untrained students. After short runs the MG concentration had decreased to 13% in the untrained men and 30% in the trained men, and after long runs the concentration had decreased to 41% in the untrained and 60% in the trained men. The MG in plasma and red blood cells appeared to have been utilized during relatively anaerobic exercise, especially by the untrained subjects. The D-lactate and related substances were also determined in urine, but the concentration of these substances showed no relationship to exercise. The D-lactate concentration in sweat samples tripled after short periods of running but the relative concentration to sodium ion concentration was not altered. The L-lactate, pyruvate, and MG concentrations in sweat increased after short duration running but their concentrations relative to sodium ion concentration were decreased significantly.     

Towards equitable and sustainable availability of blood products in Zimbabwe: An analysis of strengths,weaknesses, opportunities and challenges

Blood transfusion can be a lifesaving intervention in a number of medical emergencies. To attain sustainable and equitable availability of blood products, it is important to understand the strengths, weaknesses, opportunities, and challenges of the national blood services programme. We, therefore, with this letter to the editor, discuss some of the strengths, weaknesses, opportunities and threats to the Zimbabwean programme since its inception. Despite several strengths and opportunities that the national blood services of Zimbabwe (NBSZ) leverages on, we argue that among other challenges, donor shortages and an upsurge of transfusion transmittable infections in the eligible donor population continue to be the biggest threats to the achievement of the programme objectives. These can be addressed through expanding the blood donor base and the catchment area. Additionally, improving the level of knowledge and attitude towards blood donation in the communities is critical for driving the sustainable and equitable distribution of safe blood products to the population.     

Assessment of blood supply and usage pre- and during COVID-19 pandemic: A lesson from non-voluntary donation

BackgroundEnsuring steady stream of safe blood is the ultimate goal of blood transfusion practice. The current COVID-19 pandemic has affected almost every part of life and economy. Consequently, this study sets off to assess the effect of the pandemic on blood supply and blood transfusion in the University of Calabar Teaching Hospital.MethodsData from the Donor Clinic and Blood Group Serology Unit of the University of Calabar Teaching Hospital were retrospectively extracted to evaluate supply and use of blood before and during COVID-19 pandemic.ResultA total of 1638 donors were recorded within the study period. Age range 15–29 and 30–44 years constituted majority of the subjects (58.9% and 33.4%, respectively). The donor pool were male-dominated. Commercial donors (61.7%) and family replacement donors (30.6%) constituted majority of the donor pool. Most of the donor pool were students (37.1%), public servants (22.8%) and artisans (18.6%). A concomitant decrease of 26.1% and 18.9% were recorded in blood donation and request during the COVID-19 pandemic.ConclusionBlood supply was not significantly affected in our study center as both requests and donations decreased. Consideration for improving family replacement donation was advised.     

输血质控督查问题及解决对策

目的 通过抽查输血病案,发现临床输血管理不规范行为,探索解决方案。方法 对2017年1月~2018年12月我院输血科和医务处抽检的720份输血病案进行督查,按照我院《临床用血管理考核实施细则》进行考核,包括输血标本的采集、交叉配血是否符合要求、输血前评估、输血申请审核、大量用血审批、输血治疗知情同意书、输血前感染性标志物检测、血液交接、血液运输冷链管理、输血过程监控、不良反应回报等。结果 存在缺陷的输血病案共182份,占受检总数25.28%;缺陷病历排名前5位分别为输血申请不规范（64例）、输血后疗效评价欠缺（44例）、输血治疗同意书填写不完整（26例）、输血病程记录不完整（12例）、血液冷链运输不符合要求（8例）,占缺陷病案的84.62%;手术科室输血病案存在问题占缺陷病案总数62.64%,非手术科室缺陷输血病案占37.46%;医生记录的缺陷占缺陷病案总数91.75%,护理人员记录仅占7.02%。结论 我院临床医生记录的输血病案存在问题较多,建议严格按照临床操作技术规范执行,确保输血各个环节质量,以保证患者的用血安全。     

正常人的血液粘弹性和触变性研究

应用ＬｏｗＳｈｅａｒ４０流变仪对正常人的血液粘弹性、触变性等指标进行测定与分析，得到了全血滞后环和应力衰减曲线，发现应力的变化在突加一个切变率后并不是单纯的指数衰减，而是先经过０６ｓ左右的振荡过程，然后才开始指数衰减。弹性模量Ｇ′及耗散模量Ｇ″随振荡频率的变化在三个频点出现局部极大（极小）值，在０８Ｈｚ时Ｇ′、Ｇ″都达到谷值，应力与应变的相位差δ达到极小值，说明此振荡频率下血液的粘性分量与弹性分量之比达到最小。在０２Ｈｚ、３３Ｈｚ时Ｇ′达到谷值，Ｇ″保持上升趋势，相位差δ达到局部峰值，说明此二个振荡频率下血液的粘性分量与弹性分量之比达到最大。血液粘度的测量结果表明同心圆筒式粘度计在测量不同切变率范围（０～２００ｓ－１）的全血粘度时稳定性较锥板式差，而且在较高切变率时（１６０２００ｓ－１）数据不稳定。因此在进行一般的全血粘度测量时仍以锥板式为好。     

Zeroing in on the root cause of the clots in a blood bag: Reinforcing improvement in blood collection practices

Blood clots in the packed red blood cell [PRBC] unit can sometimes go unrecognized and could eventually give rise to flow problems while administering the same. We herein report our observation of a moderately elongated threadlike clot in a PRBC unit prepared from a whole blood donated by a young Indian male donor. The PRBC unit was returned to us from the ward by the nursing staff citing “flow issues”. In fact, this warranted the initiation of root-cause analysis of the entire event led by two faculty members, one post-graduate student and the technical supervisor at our blood centre.     

Specific resistance of blood at body temperature II

The specific resistance values for samples of goat, sheep, camel, monkey, baboon, cat and pig blood at 37°C are given for a range of packed-cell volumes extending from 0 to 70%. The relationship is presented in the form p=Aeα^H, when p is the specific resistance, A and α are constants and H is the packed-cell volume in percent. In addition, values for the change in resistivity with the addition of saline are presented to allow electrical calibration for conductivity cells when saline is used as the indicator in cardiac-output studies.     

Éthique et transfusion sanguine – Échos d’un séminaire –

This paper brings together the abstracts and proceedings of a seminar held on the topic of “ethics and transfusion”, October 15, 2013 at the National Institute of Blood Transfusion, Paris.     

Ultrafiltration of circulating blood in vivo

Summary A method of continuous ultrafiltration of circulating blood in the intact rat is described. Thus, the serum concentrations of substances can be continuously followed, whose measurement in whole blood is made impossible by the corpuscular and macromolecular elements. As an example, conductivity curves in portal venous blood of the conscious rat after intraduodenal hydration are presented.