磁悬浮离心式心室辅助装置的体外溶血测试**

背景：心室辅助装置已广泛应用于心力衰竭患者的治疗。虽然有不同的血泵在国外应用于临床,却很少在国内应用,主要原因是其价格太高。因此在国内研制相对价格较低的能应用于临床的自主血泵迫在眉睫。 目的：测试置入式磁悬浮离心心室辅助装置主体血泵的溶血性能。 方法：通过计算流体力学方法,对磁悬浮离心式心室辅助装置主体血泵内部流场做初步分析。血泵在后负荷100 mm Hg     (1 mm Hg=0.133 kPa)、流量5 L/min 情况下,通过体外模拟血循环系统驱动羊血测试血泵体外溶血性能,计算血泵实际标准溶血指数NIH。 结果与结论：在设计工况下计算流体力学结果显示血泵内部流线平稳,整个流道内部壁面剪切力均在68.5 Pa以下,内部静压力分布均匀,过渡平稳,没有不良区域出现。体外溶血实验测得标准溶血指数NIH值为(0.075±0.017) mg/L。提示血泵驱动叶片及内部流道设计合理,同第3代血泵相比有较好溶血性能。血泵实验期间无不良状况发生,可以进行下一步长期的动物体内实验,进而评估血泵体内血流动力学性能和血泵置入对实验动物脏器的影响。     

磁驱动血泵溶血分析

测试磁驱动轴流心室辅助装置主体血泵溶血性能。利用计算流体力学(CFD)软件ANSYS,基于红细胞受到切应力和相应曝光时间的计算溶血方法预测血泵溶血性能,计算红细胞粒子随着时间推移在血泵内运动轨迹上受到破坏程度。通过体外模拟循环实验实际测试血泵体外溶血性能,计算得到血泵实际标准溶血指数。CFD计算结果转化的标准溶血指数与实际体外实验结果比较相差较大,与CFD计算简化和实际计算循环周期有很大关系。磁驱动轴流心室辅助装置主体血泵有较好的实际溶血性能,血泵实验期间无不良状况发生,可以进行进一步实验。     

一种新型轴流式心脏辅助血泵的研制和初步的动物实验

目的研制开发一种新型的轴流式心室辅助泵,并对其基本性能和血液相容性能进行测试。方法应用计算流体力学（CFD）计算机辅助设计,利用五坐标数控机床上对其进行加工,并通过体外测试台和动物实验,对血泵的流体力学性能和血液相容性能进行了测试。结果轴流泵在后负荷为100mmHg情况下,流量在5L/min以上。动物实验中,血浆游离血红蛋白的含量为0.05g/dL。结论血泵体外测试所提供的输出压力和流量符合临床心力衰竭患者的需要,动物实验结果表明其血液相容性能较为满意,值得进一步改进。     

一种植入式磁悬浮离心血泵的体外流体力学实验研究

通过体外模拟循环实验台对一种植入式磁悬浮离心血泵进行体外流体力学实验。以新鲜羊血为循环介质,通过体外循环台测定在后负荷为100 mmHg,血泵在不同转速下的输出量;通过控制血泵的转速,测定在固定泵速下不同后负荷下的输出量。血泵测试工作电压为24 V,电流波动于0.3～0.75 A。血泵功率为7.2～18 W。在后负荷为100 mmHg下,泵速在2 900～3 900 rpm,输出流量为3～7.1 L/min。泵速为2500～3 500 rpm,血泵在后负荷69～163 mmHg下输出流量为1.02～5.87 L/min。在固定的转速下血泵的压力-流量呈负相关关系。体外实验血泵工作性能稳定,可以满足成人心室辅助的需求。血泵功率偏高仍需要进一步改进。     

一种植入式磁悬浮离心血泵的体外流体力学实验研究

通过体外模拟循环实验台对一种植入式磁悬浮离心血泵进行体外流体力学实验.以新鲜羊血为循环介质,通过体外循环台测定在后负荷为100 mmHg,血泵在不同转速下的输出量；通过控制血泵的转速,测定在固定泵速下不同后负荷下的输出量.血泵测试工作电压为24V,电流波动于0.3～0.75 A.血泵功率为7.2～18W.在后负荷为10...     

叶片倒角对FDA标准血泵流场和溶血预测的影响

目的采用计算流体力学(computational fluid dynamics, CFD)方法研究FDA标准离心血泵叶片倒角对流场和溶血的影响。方法针对FDA标准离心泵,模拟3个工况下水力学性能、流场形态、溶血指数等血泵关键性能,并进一步比较叶片结构有、无倒角时对前述模拟结果造成的影响。结果血泵叶轮倒角对血泵压头(无倒角特征与有倒角特征压头计算值最大百分比差异为57.38%)、流场等均有影响,从而导致溶血预测值也有显著差别(两者最大误差超过1个数量级)。结论对叶轮进行有倒角处理有助于优化血泵的性能。研究结果对更好使用CFD辅助血泵的血液相容性设计具有重要意义。     

基于fluent离心式血泵内流场仿真与结构优化

提高溶血性能,降低溶血率作为血泵性能优化的一个重要指标,对血泵的结构优化具有重要的指导意义。本文基于一款离心式血泵通过使用计算流体力学（CFD）技术,采用非结构化网格、N-S方程和标准K-ε湍流模型在fluent中模拟分析出不同工况下血泵流场内部的剪切力场、压力场等重要参数并根据叶轮流场数据分析,提出了4种不同的结构优化方案;并基于三维快速溶血预估模型计算出不同流量、不同叶轮结构下血泵的溶血性能。仿真结果显示:当叶片与叶轮径向夹角为45°,流量达到5 L/min、转速为2 100 r/min时,扬程为115 mmHg,溶血率达到0.022 1 g/100 L,优化后模型较原模型溶血率提升40.9%,满足人体泵血生理需求。实验结果显示:选用优化后结构进行实验分析,得到扬程的实验数据与仿真数据相互验证,进一步证实了该仿真结果的准确性。     

一种可植入式磁悬浮离心血泵的流场分析

目的 设计和研发满足心室辅助要求的植入式磁悬浮离心血泵.方法 应用计算机辅助设计(CAD)一种磁悬浮式的离心血泵,应用计算机流体力学方法对新型血泵的流场进行分析.结果 ①在血泵流道内血液流动无滞留区域.②叶轮底端血液由外向内进入中心悬浮装置下端,并经过中心悬浮装置与叶轮之间的空隙回流入叶轮中心.③叶轮上端血液回流入叶轮中心,并与流入道的血液汇合,重新流入凹槽内.结论 血液在血泵流道充分流动无滞留部位.叶轮上下端有部分血液回流可以使血泵工作效率降低,但回流的血液具有防止血栓形成、协助叶轮悬浮、防止局部过热的作用.血泵入口叶轮衔接部位及血泵出口衔接部位为潜在涡流区域.     

混流式血泵的数值模拟及性能分析

轴流式血泵转速过高、离心式血泵容易产生流动死区是造成血液损伤的重要原因,而混流式血泵能有效缓解轴流式血泵的转速过高以及离心式血泵的流动死区问题。基于此,本研究旨在探究闭式叶轮混流式血泵的性能效果。通过数值模拟的方法对闭式叶轮混流式血泵进行数值模拟,分析该类型血泵的流场特性及压力分布情况,探讨其水力性能以及可能对红细胞造成的损伤程度,并与半开式叶轮结构混流式血泵的数值模拟结果进行性能对比。结果表明:本研究中的闭式叶轮混流式血泵具有良好的性能,能够安全高效运行。该泵在5 L/min下能够达到100 mm Hg的扬程,血泵内流动均匀,没有明显的涡流、回流以及流动停滞现象,压力分布均匀合理,可有效地避免血栓;溶血指数平均值(HI)为4.99×10^-4,具有良好的血液相容性;与半开式叶轮混流式血泵相比,闭式叶轮混流式血泵扬程和效率更高、溶血指数平均值更小,且具有更好的水力性能及避免血液损伤的能力。通过本文研究结果,或能为闭式叶轮混流式血泵的性能评价提供依据。     

螺旋血泵的CFD分析

溶血和血栓是目前国内心室辅助装置不能应用于临床的主要原因。血泵的不良血液动力学特性是导致溶血和血栓的主要因数。计算流体力学（CFD）方法目前被广泛应用于血泵设计,它可以准确有效地反映血泵内部流场状态、血泵压力流量曲线以及血泵内部流场剪切力分布状态等。本研究采用CFD方法对自制螺旋血泵的泵腔、出入流口进行流场分析,内部流场采用三维彩图显示。结果显示CFD分析结果很好的与体外实验结果吻合。血泵血液动力学特性,以及内部血流状态采用CFD方法分析,可以有效地分析血泵血液相溶性方面的问题。     

Measurement of hemodynamic changes with the axial flow blood pump installed in descending aorta

We have developed various axial flow blood pumps to realize the concept of the Valvo pump, and we have studied hemodynamic changes under cardiac assistance using an axial flow blood pump in series with the natural heart. In this study, we measured hemodynamic changes of not only systemic circulation but also cerebral circulation and coronary circulation under cardiac support using our latest axial flow blood pump placed in the descending aorta in an acute animal experiment. The axial flow blood pump was installed at the thoracic descending aorta through a left thoracotomy of a goat (43.8 kg, female). When the pump was on, the aortic pressure and aortic flow downstream of the pump increased with preservation of pulsatilities. The pressure drop upstream of the pump caused reduction of afterload pressure, and it may lead to reduction of left ventricular wall stress. However, cerebral blood flow and coronary blood flow were decreased when the pump was on. The axial flow blood pump enables more effective blood perfusion into systemic circulation, but it has the potential risk of blood perfusion disturbance into cerebral circulation and coronary circulation. The results indicate that the position before the coronary ostia might be suitable for implantation of the axial flow blood pump in series with the natural heart to avoid blood perfusion disturbances.     

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。     

磁耦合驱动搏动式血泵的可行性研究

目的提出一种磁耦合驱动搏动式血泵结构并验证其可行性。方法基于磁场传递往复作用力模型以及推拉互挽式结构设计磁耦合驱动搏动血泵,通过建立磁力驱动模型,计算耦合力大小,制作样机并对样机进行体外循环模拟试验,获得压力和流量实验数据。结果采用生理盐水作为循环介质,固定后负荷,增加前负荷,血泵输出量减少,没有明显线性趋势;固定前负荷,增加后负荷,血泵输出量减少,且具有一定线性趋势。设置驱动频率为75次/min时,调节前、后负荷改变范围分别为0.665~3.990 k Pa(5~30 mm Hg)和5.320~11.970 k Pa(5~30 mm Hg),可使输出量在保证线性关系条件下达到2.0~3.1 L/min。结论该搏动式血泵流体力学特性基本满足体外膜肺循环的需要,仍需进一步研究和改进;研究结果具有重要的应用前景,尤其对替代目前临床体外膜肺氧合设备的血泵装置具有重要意义。     

Challenges in longer-term mechanical support of fontan circulation in sheep

Single ventricle congenital heart defects are usually palliated with the end result of a Fontan circulation. Despite improving results, this circulation is still associated with long-term failure. We previously developed an animal model of mechanical cavopulmonary circulation support that was successful in the acute and mid-term period. In the current study, we evaluated longer support durations in five Western-breed sheep. Through a right thoracotomy we instituted mechanical support from the inferior vena cava to the pulmonary artery, using a Heartmate II axial flow pump (Thoratec Corp., Pleasanton, CA). Postoperatively, the animals were anticoagulated with heparin iv. Hemodynamics, pump flow, anticoagulation, and hepatic and renal function were monitored daily. All animals survived the operation. Signs of moderate liver and kidney injury in general reversed quickly. Two animals had a fatal pump thrombosis. When anticoagulation was effective, hemodynamics and pump flow were maintained to normal values. Effective anticoagulation was difficult to achieve because of the high variability in response to heparin. Survival up to 18 days was accomplished. This study is the longest reported survival of animals with a mechanically assisted cavopulmonary circulation. The performance of the Thoratec Heartmate II has been good, but the issue of effective anticoagulation has not yet been solved.     

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...     

An Indirect Monitoring System for Controlling Rotor Blood Pumps

Control of rotor blood pumps by rotor rotation rate should be adapted to the requirements of the patient’s body. Physiological control of rotor blood pumps is based on information about the blood circulation system. The sensors should not contact the patient’s body fluids, so an indirect control system is suggested in this work. The system is based on information about pump current and rotor rotation rate. The indirect control system gives important information about parameters of the blood circulation system and the blood pump.     

Development of Control Unit and Power Source for an Implantable Assisted Circulation Pump

Development of a control unit and power source for an implantable assisted circulation pump is discussed. The device for left ventricle assistance was developed in the Shumakov Federal Scientific Center for Transplantology and Artificial Organs, Moscow State Institute of Electronic Engineering, and BIOSOFT-M, Ltd. The device provides a basis for a safe portable pacemaker meeting the requirements of extracorporeal circulation systems (ECS). The aspects of engineering, structural, and software support of the system are discussed. An implanted axial pump (IAP) of the ECS for artificial left cardiac ventricle (ALCV) is considered.     

Development and evaluation of endurance test system for ventricular assist devices

We developed a novel endurance test system that can arbitrarily set various circulatory conditions and has durability and stability for long-term continuous evaluation of ventricular assist devices (VADs), and we evaluated its fundamental performance and prolonged durability and stability. The circulation circuit of the present endurance test system consisted of a pulsatile pump with a small closed chamber (SCC), a closed chamber, a reservoir and an electromagnetic proportional valve. Two duckbill valves were mounted in the inlet and outlet of the pulsatile pump. The features of the circulation circuit are as follows: (1) the components of the circulation circuit consist of optimized industrial devices, giving durability; (2) the pulsatile pump can change the heart rate and stroke length (SL), as well as its compliance using the SCC. Therefore, the endurance test system can quantitatively reproduce various circulatory conditions. The range of reproducible circulatory conditions in the endurance test circuit was examined in terms of fundamental performance. Additionally, continuous operation for 6 months was performed in order to evaluate the durability and stability. The circulation circuit was able to set up a wide range of pressure and total flow conditions using the SCC and adjusting the pulsatile pump SL. The long-term continuous operation test demonstrated that stable, continuous operation for 6 months was possible without leakage or industrial device failure. The newly developed endurance test system demonstrated a wide range of reproducible circulatory conditions, durability and stability, and is a promising approach for evaluating the basic characteristics of VADs.     

磁液悬浮离心血泵体外溶血的实验及耐久性实验

通过建立模拟循环管路系统来研究磁液悬浮离心血泵的溶血性能及机械稳定性。建立体外模拟循环管路系统,体外溶血实验中以新鲜羊血为循环介质,调节前负荷和后负荷分别为15、100 mmHg,血泵转速设定为2 900 rpm,测定血浆游离血红蛋白含量（FHb）和红细胞压积（Hct）,计算血泵标准溶血指数（NIH）;耐久性试验其他各项设定同体外溶血实验,循环介质改为甘油水溶液。在体外溶血实验中,测得磁液悬浮离心血泵NIH值为（0.0038±0.0008）g/100L;耐久性实验中血泵连续正常运转90 d,期间无卡壳、停泵等现象,电压、电流、转速稳定。该血泵溶血性能处于较高水平,机械性能稳定可靠,满足进一步进行动物实验的要求。     

Computational analysis of the effect of the control model of intraaorta pump on ventricular unloading and vessel response

The intraaorta pump is a novel left ventricular assist device (LVAD) whose hemodynamic effects on the circulatory system is unknown. This article aims to evaluate the different effects on the circulatory system supported by the intraaorta pump. In this article, the pump is controlled by three control strategies, including the continuous flow method, the constant rotational speed, and the constant pressure head. A cardiovascular pump system, which includes cardiovascular circulation, intraaorta pump, and regulating mechanisms of systemic circulation, has been proposed. Left ventricle pressure (LVP), end-diastolic volume (EDV), and left ventricular external work (LVEW) were used to evaluate the degree of ventricular unloading. The pulsatile index (PI), which is defined as a ratio of pulse pressure and mean arterial pressure (MAP), was used to evaluate the effect of the vessel response by three control strategies. The comparison results showed that LVP and EDV were lower than those measured before the intraaorta pump was implanted. For LVEW, the constant pressure head strategy provided a superior ventricular unloading compared with other strategies. Support of the pump led to the lower pulsatility by the three models. However, the PI of the constant pressure head was the most at 0.37. In conclusion, these results indicate that the intraaorta pump controlled by constant pressure head strategy provides superior ventricular unloading and pulsatility of the vessel.