往复式电磁铁驱动搏动式血泵的可行性研究

目的为了得到更适合血液循环的动力装置,提出一种用于体外膜肺氧合(extracorporeal membrane oxygenation,ECMO)系统由电磁铁驱动的搏动式血泵,并研究其可行性。方法首先利用电磁原理设计出电磁驱动机构,主要部件包括对称的两个电磁铁和压簧,两个电磁铁交替通电下使得动铁芯往复运动;利用容积控制原理,泵腔在动铁芯的驱动下收缩舒张;然后根据上述原理设计出血泵模型,包括电磁驱动部件和泵腔;最后建立包括血泵、电路控制部分、示波器、加速度传感器、输入输出管路和储液池的试验台,对血泵模型进行驱动力和流量输出测试。结果血泵模型在通电电压7～12 V时动铁芯的初始驱动力为2. 97～8. 00 N。血泵模型产生的初始驱动力与工作电压呈正相关非线性关系,当通入电压12 V时血泵模型初始驱动力满足要求。当前压与后压为0、频率80次/min、工作电压7～12 V时的流量输出为0. 97～3. 81 L/min。当前压与后压为0,工作电压12 V、频率60～90次/min时的流量输出为3. 1～3. 8 L/min。当工作电压12 V、频率80次/min、前压0～40 cm H2O和后压50～110 cm H2O时的流量输出为0. 55～3. 59 L/min。血泵流量与工作电压和频率呈正相关,与后压呈负相关,与前压无显著性相关。结论往复式电磁铁驱动搏动式血泵基本满足ECMO临床要求,具有广泛的应用前景,对体外循环血泵的发展具有重要意义,但仍需进一步研究和改进。     

基于电磁驱动的体外膜肺氧合搏动式泵血系统

根据电磁学原理建立梯度线圈-永磁体模型,本研究设计了一款新型电磁驱动搏动式血泵,主要包括驱动装置、泵头装置、冷却系统以及体外循环管路等.搏动式血泵运动速率接近正常人体心率,模仿心脏的节律跳动,产生搏动式血流,实现了搏动式泵血.通过搭建实验平台,采集基于电磁驱动的体外膜肺氧合(extracorporeal membran...     

电磁搏动式血泵的温度场仿真分析

电磁搏动式血泵是基于电磁感应原理制作而成的,长时间通电工作会引起血泵升温。如果血泵温度过高会使血泵损坏,甚至可能使泵内循环血液温度过高,对血液成分造成破坏甚至威胁生命,因此研究电磁搏动式血泵温度,对其进行温度场分析是必要的。通过使用有限元分析软件对血泵进行温度场分析,可以直观观察血泵工作温度。仿真结果表明,在设定电磁搏动式血泵工作1 h情况下,血泵温度最高处在驱动绕组处,最高温度为100.3℃,泵内与37.0℃循环血液接触面的温度变化不大,最高温度为37.5℃,因此电磁搏动式血泵不会对血液成分造成破坏,但是需要对驱动绕组进行降温处理以免破坏血泵,对循环血液造成影响。     

短期辅助用直流电磁驱动搏动式血泵设计与测试

设计一种直流电磁驱动搏动式血泵并测试样机性能指标。首先,提出一种通过直流螺线管使永磁体进行往复直线运动的驱动方法,并通过螺线管内部磁场的数值模拟设计内部磁场趋于匀强磁场的补偿螺线管结构,结合两者设计直流电磁驱动搏动式血泵。然后,通过制作样机并搭建加速度实验台,测量接入不同直流电流时血泵样机可提供的磁力驱动力,并验证通电螺线管发热问题。最后,搭建流量实验台,在前、后负荷范围分别为5~30和50~80 mmHg的情况下,测量血泵样机的流量性能指标。血泵样机提供的磁力驱动力与电流呈正相关线性关系,并且在接入2.7 A的电流时,其数值大小即可满足驱动要求;在接入的直流电流为2.7 A且血泵驱动频率为80 次·min^-1时,一方面通电螺线管与血液接触的内表面温度上升1 ℃后平稳在27 ℃,另一方面除了前、后负荷压差达到70 mmHg及以上,血泵样机流量均大于3.0 L·min^-1。该直流电磁驱动血泵满足离体器官灌注和体外循环短期辅助的临床要求,且对体外循环血泵的发展具有重要意义。     

基于计算流体动力学的新型电磁驱动搏动式灌注血泵泵头优化分析

目的应用计算流体动力学(computational fluid dynamics,CFD)方法对电磁驱动搏动式灌注血泵流场进行仿真分析,通过改进泵头结构改善血液在血泵的流动状态,提升其抗溶血性能。方法应用Fluent 17. 0分析泵头结构变化对泵内流场的影响,通过血液流入和流出的4次仿真实验,分析内部液体的流线分布、中轴面上的湍流动能分布、血液流经泵头的压力损失和模型表面受到的切应力。结果在4次实验中,泵头入口与出口管路对称且与对称轴的夹角α=30°时,液体流线无明显紊乱,湍流程度较低;实验1中压力损失最小,为376. 8 Pa;实验1、2中的最大切应力分别为258. 6、302. 8 Pa,符合压力损失和溶血程度等血泵生物力学性能要求。选择α=30°模型为该电磁驱动搏动式灌注血泵的泵头结构,并通过3D打印技术进行制作。结论经过对泵头的优化分析,血泵溶血性能得到改善。研究结果可以运用到新型电磁驱动搏动式灌注血泵的设计与实验中。     

搏动式血泵的电磁驱动装置设计及可行性研究

为了实现搏动式血泵的驱动,设计了一种新型电磁驱动装置。基于模拟体外循环实验对装置进行相关的可行性实验研究。研究结果表明:驱动线圈结构设计过程科学合理,且驱动力规律满足血泵驱动要求;平均灌注压与驱动电流的线性拟合方程为y=33. 074x+6. 6563,R^2=0. 9784,表明该驱动装置能够按照设定的压力值输出搏动流以满足实际应用需求。装置的驱动效率为21. 83%。研究表明我们所设计的新型驱动装置能够作为搏动式血泵驱动。     

新型电磁搏动式血泵的实验研究

目的探究一种新型电磁搏动式血泵的动力输出性能及血液相容性。方法首先通过建立理论模型对该血泵驱动力进行分析,并基于该模型计算出满足条件的实验驱动电压。设计体外模拟循环实验,对新型血泵的输出流量和输出压力特性及血泵的体外溶血性能进行初步实验研究。结果实验测得当血泵后负荷为73.5 mmHg(9.78 kPa, 1 mmHg=0.133 kPa)、驱动电压达到35 V、搏动频率为75/min时,实际输出的流量为3.18 L/min,可以提供高压132 mmHg(17.56 kPa)、低压66 mmHg(8.78 kPa)、平均压力98 mmHg(13.03 kPa),体外实验标准溶血指数(normalized index of haematolysis, NIH)为(0.049 15±0.003 75) mg/dL。结论该新型搏动式血泵能够满足离体器官灌注和体外循环短期辅助的临床要求,对体外循环血泵的发展具有重要意义。     

无泵驱动体外膜肺氧合临床应用进展

对无泵驱动体外膜肺氧合支持疗法的优缺点、并发症和临床应用状况进行总结。临床应用证明无泵驱动体外膜肺氧合疗法应用于呼吸功能衰竭的患者可以降低并发症,提高救治的成功率。     

旋转血泵产生低溶血搏动流的方法

为减少心室辅助装置中叶轮泵输出搏动流对血液成分的破坏作用,我们将泵的入口和叶轮外形轮廓设计成锥形,研制出博动流轴流泵;并设计出扭曲形叶片的叶轮,周期性的改变叶轮的转速,研制出搏动流离心泵。理论分析和实验表明这两种类型的装置均无明显附加紊流产生,也没有对血液成分产生破坏,具有较强实用性。     

三种叶片式血泵的体外溶血试验研究

血泵对血液的破坏程度是衡量血泵性能的一个重要指标。本文针对三种叶片式血泵即离心泵、轴流泵、混流泵的溶血试验做一比较分析。在试验中 ,选用了我们研制的Ⅰ型离心血泵、磁耦合型轴流血泵、螺旋混流泵。在一封闭管道中 ,注入新鲜抗凝羊血 5 0 0ml,水浴温度 37℃ ,血泵辅助流量为 5L min ,平均压力10 0mmHg,分别在泵转后 0、 0 5、 1 0、 1 5、… 4 0h测量血浆中游离血红蛋白 (FHB)和纤维蛋白原 (FIB)含量 ,最后计算出三个血泵整个过程中的标准溶血指数NIH。结果表明三种血泵对血液都有一定的破坏 ,它们的NIH值分别为 0 112 5± 0 0 15 7g 10 0L、 0 0 931± 0 0 137g 10 0L和 0 0 5 6 1± 0 0 0 5 8g 10 0L ,由此可得出混流泵对血液的破坏最小。     

Up to 151 days of continuous animal perfusion with trivial heparin infusion by the application of a long-term durable antithrombogenic coating to a combination of a seal-less centrifugal pump and a diffusion membrane oxygenator

We developed a new coating material (Toyobo-National Cardiovascular Center coating) for medical devices that delivers high antithrombogenicity and long-term durability. We applied this coating to an extracorporeal membrane oxygenation (ECMO) system, including the circuit tube, cannulae, a seal-less centrifugal pump, and a diffusion membrane oxygenator, to realize prolonged cardiopulmonary support with trivial anticoagulant infusion. The oxygenator consisted of a hollow-fiber membrane made of polymethylpentene, which allows the transfer of gas by diffusion through the membrane. The centrifugal pump was free of seals and had a pivot bearing. We performed a venoarterial bypass in a goat using this ECMO system, and the system was driven for 151 days with trivial anticoagulant infusion. Plasma leakage from the oxygenator did not occur and sufficient gas-exchange performance was well maintained. In the oxygenator, thrombus formation was present around the top and the distributor of the inlet portion and was very slight in the outlet portion. In the centrifugal blood pump, there was some wear in the female pivot region and quite small amounts of thrombus formation on the edge of the shroud; the pivot wear seemed to be the cause of the hemolysis observed after 20 weeks of perfusion and which resulted in the termination of the perfusion. However, no significant amounts of thrombus were observed in other parts of the system. This ECMO system showed potential for long-term cardiopulmonary support with minimal use of systemic anticoagulants.     

Fault-tolerant strategies for an implantable centrifugal blood pump using a radially controlled magnetic bearing

In our laboratory, an implantable centrifugal blood pump (CBP) with a two degrees-of-freedom radially controlled magnetic bearing (MB) to support the impeller without contact has been developed to assist the pumping function of the weakened heart ventricle. In order to maintain the function of the CBP after damage to the electromagnets (EMs) of the MB, fault-tolerant strategies for the CBP are proposed in this study.Using a redundant MB design, magnetic levitation of the impeller was maintained with damage to up to two out of a total of four EMs of the MB; with damage to three EMs, contact-free support of the impeller was achieved using hydrodynamic and electromagnetic forces; and with damage to all four EMs, the pump operating point, of 5 l/min against 100 mmHg, was achieved using the motor for rotation of the impeller, with contact between the impeller and the stator.     

Development of an axial flow blood pump: Characteristics of a magnetic fluid seal

In the development of a rotary blood pump, one of the major problems is thrombus formation near the shaft seal. To solve this problem, a magnetic fluid seal was developed for use in an axial flow pump. A magnetic fluid seal has several advantages, including a high degree of airtightness, no wear or noise, no heat generation, and a simple structure. To determine the reliability of the seal, the sealing pressure, durability, and amount of magnetic fluid mixed with liquids were examined. The seal was composed of two ferromagnetic polepieces and a Nd−Fe−B magnet. The magnetic fluid (LS-40) was injected into the gap between the motor shaft and the polepieces. To minimize leakage of the magnetic fluid, a shield was provided on the polepiece on the liquid side. Sealing pressures at motor speeds up to 10 000 rpm were measured with the seal immersed in water or bovine blood. The sealing pressures were 195 mmHg in water and 173 mmHg in blood. The results of magnetic FEM showed that the theoretical sealing pressure was about 230 mmHg for motor speeds up to 10 000 rpm. This result was almost the same as the measured pressure in was 691+ days (ongoing) at 8000 rpm and 51 days, and 47+ days (ongoing) in a rotating condition. There was only a small amount of magnetic fluid mixed with the liquid. The especially designed magnetic fluid shaft seal is considered to be useful for an axial flow pump.     

体外循环用血泵研究进展

本文在阐述体外循环原理及临床意义的基础上,简单介绍了体外循环用血泵的原理、特点以及关键技术评价指标,重点分析了离心血泵的发展历史,及二代、三代离心血泵磁力驱动的工作原理和特点。第二代血泵采用圆盘形磁力耦合器驱动方式,其永磁体采用组合拉推式结构。第三代血泵是在第二代血泵的基础上增加了磁悬浮系统。最后展望了体外循环用离心血泵的发展趋势。     

二氧化碳血液净化仪实验研究

目的探讨气体传输型二氧化碳血液净化仪在呼吸衰竭(RF)治疗中实施体外膜肺氧合(ECMO)部分循环支持的实验研究。方法建立实验犬的RF模型,用BaxterEF-550血管路连接二氧化碳血液净化仪,股静脉置入双腔单针导管行V-V转流,转流过程中维持血流量200mL/min,氧入通入量4L/min~6L/min,转流开始10min后,分别采集动脉血及膜式人工肺出入端血标本,以后每转流60min分别采集血标本进行血气分析。结果人工肺出入端PCO2可由50.93mmHg±1.62mmHg~63.27mmHg±0.46mmHg下降为1.27mmHg±0.05mmHg~14.07mmHg±1.86mmHg,PO2上升值为371.6mmHg±42.67mmHg~614.6mmHg±50.35mmHg,人工肺出入端PCO2、TCO2、PO2、SO2、O2-C变化均有显著性差异(P<0.01)。转流60min,实验犬体动脉血PaO2从39.6mmHg,升高为56.7mmHg±2.36mmHg,PCO2由52.8mmHg下降为50.4mmHg±0.53mmHg。结论二氧化碳血液净化仪有良好的二氧化碳血液净化和氧传输双重性能;二氧化碳血液净化仪的气体传输性能,在0.2L/min流量时,可以使活体实验动物血气发生改变———氧摄入和二氧化碳排出增多,从而简化了ECMO技术并实现呼吸支持的作用,为呼吸衰竭的救治提供一项新的技术和途径。     

Artificial lungs: current state and trends of clinical use and research and development

This article describes recent progress in the field of artificial lungs, centering on the current state and trends in clinical use and research and development. Trends in the recent clinical use in Japan can be found in shipment-number-based surveys as well as in the questionnaire surveys for clinical extracorporeal membrane oxygenation (ECMO) and percutaneous cardiopulmonary support (PCPS). It is likely that the use of artificial lungs for open-heart surgery has peaked, and this can be attributed to the rapid expansion and popularization of off-pump coronary artery bypass grafting surgery. In contrast, the increase in the number of artificial lungs used in assisted circulation cases is showing significant growth. Along with such clinical trends, research and development toward next-generation systems is active in the field of assisted circulation, focusing on emergency or long-term use of PCPS or ECMO. Approaches include enhancing the performance of conventional systems in terms of long-term durability and hemocompatibility, developing a novel device by integrating the oxygenator with the blood pump, and developing an implantable type of artificial lung such as an intravenous oxygenator. Next-generation devices not only will benefit a multitude of patients but also represent an important target with the prospect for expansion of the market for artificial lungs. In the future, further expansion of research and development in this field, as well as progress in practical and clinical applications of innovative devices, is expected.     

基于热流耦合的轴流式血泵温升影响因素研究

人工心脏已进入临床发展阶段,溶血现象是制约人工心脏长久使用的一大难题。不正常的温度条件会使红细胞的正常生理机能和形态发生改变,从而影响其携氧能力。为研究人工心脏正常运转时的温升情况,先利用Solidworks软件建立轴流式血泵的三维仿真模型,然后基于ANSYS Workbench软件对血泵整体进行热流耦合温度场仿真,探究了定子绕组相阻值、血泵转速、定子外壳和泵外壳之间的气隙导热系数以及血液导热系数对血泵及血液整体温升的影响。结果表明,在满足血泵供血要求的前提下,适当减小定子绕组相阻值、降低转速可有效降低血泵整体温升,而气隙物质和血液导热系数的变化对血泵整体温度的影响不是很明显。