面向新功能恢复的人工心脏泵分层控制策略研究

发布时间：2018-03-31 12:01

本文选题：心功能恢复　切入点：人工心脏泵　出处：《北京工业大学》2013年博士论文

【摘要】：心力衰竭（心衰）是一种严重威胁人类健康的疾病。晚期心衰最有效的治疗方法是心脏移植与人工心脏辅助。由于移植心脏数量不足，人工心脏得到快速发展。随着人工心脏使用量的增加，由其引发的心脏功能恢复现象引起了极大的关注。然而目前尚未建立以促进心脏功能恢复为目的的人工心脏控制策略。人工心脏泵是由北京工业大学研制的新一代人工心脏。本文的研究目标是通过控制人工心脏泵与人体的相互作用，促进心脏功能的恢复。为此，本文建立面向心功能恢复的人工心脏泵分层控制策略以解决人工心脏泵治疗心衰中面临的三方面问题：如何确定人工心脏泵的最佳辅助水平；如何满足循环系统的血液灌注与心脏卸载需求；以及如何维持人工心脏泵系统的控制稳定性。针对上述问题，论文开展三方面研究。第一，建立循环系统与人工心脏泵壀合模型，为人工心脏泵控制策略研究提供被控对象。首先，建立循环系统集中参数模型以研究循环系统血流动力学机理。其次，建立压力反射系统（Baroreflex System）数学模型以研究压力反射系统对心率的调节机制。再次，建立人工心脏泵流体力学模型以研究人工心脏泵的流体特性。最后，建立循环系统与人工心脏泵壀合模型将循环系统集中参数模型、压力反射系统数学模型以及人工心脏泵流体力学模型进行壀合，并采用数值方法研究壀合模型的有效性。第二，设计人工心脏泵分层控制策略，解决人工心脏泵促进心脏功能恢复中面临的三个问题。首先，设计外层控制策略确定循环系统的最佳辅助水平。其次，设计中层控制策略以满足循环系统血液灌注与心脏卸载的需求。控制策略采用心率来反映循环系统血液灌注需求的变化；设计血流辅助指数（BAI)反映心脏卸载水平的变化。再次，设计内层控制策略维持人工心脏泵系统的控制稳定性。最终，根据这三个问题的研究结论建立人工心脏泵分层控制策略，并利用数值方法，体外实验方法与动物实验方法研究分层控制策略的辅助效果。第三，研究人工心脏泵辅助引起的血液搏动性改变及其辅助模式对循环系统的血流动力学影响。首先，设计人工心脏泵搏动控制策略补偿人工心脏泵辅助引起血液搏动性的变化。其次，设计恒速辅助模式、同步辅助模式与反搏辅助模式等三种人工心脏泵辅助模式，采用数值方法研究三种辅助模式对循环系统产生的血流动力学影响。论文的研究工作共获得三个主要结论。第一，循环系统与人工心脏泵壀合模型能够准确地反映人工心脏对循环系统的血流动力学影响。一方面能够准确地模拟心衰状态下循环系统血流动力学特性；另一方面壀合模型能够准确地模拟人工心脏泵对循环系统血流动力学的影响。第二，本文建立的外层控制策略能够确定循环系统的最佳辅助水平，调整时间小于5s;中层控制策略能够满足循环系统血液灌注与心脏卸载的需求；内层控制策略能够减小系统的内部不确定性与外部扰动对人工心脏泵系统控制稳定性的影响，最大误差为O.lL/min;分层控制策略在一个控制策略中有效地解决上述三方面问题，并且系统调整时间小于5s，最大误差为O.lL/min。动物实验研究表明分层控制策略能够准确地确定实验动物的最佳辅助水平，，并且能够获得血液灌注需求与心脏卸载水平之间的最优组合。第三，人工心脏泵辅助能够直接影响循环系统的血流动力学特性。一方面，本文设计的人工心脏泵搏动控制策略能够补偿辅助过程中循环系统的血液搏动性的变化，使人工心脏泵辅助下循环系统的血液搏动性恢复正常。另一方面，同步辅助模式与反搏辅助模式能够更好地实现心脏卸载，其中同步辅助模式在实现最好的心脏压力卸载的同时能够产生最大的血液搏动性；而反搏辅助模式在实现心脏容积卸载的同时能够获得最小的心脏等效后负荷。论文的工作具有三方面创新性。1、论文首次提出了通过分层控制已达到优化人工心脏泵辅助水平和促进心脏功能恢复的方法。2、论文建立了外层控制策略确定心脏的最佳辅助水平，并作为优化人工心脏泵输出的控制变量；首次提出了血流辅助指数用于检测和控制心脏卸载水平；建立的中层控制策略能够平衡血液灌注与心脏卸载的需求；建立的内层控制策略能够维持人工心脏泵系统的控制稳定性。3、体外模拟实验、动物实验与临床应用验证该控制系统能够满足心脏辅助水平、血液灌注与心脏卸载以及人工心脏泵系统控制稳定性等三方面需求，确保了实验研究中动物和人体血液循环系统的正常运转。使用该控制系统的人工心脏已经成功应用于临床病例与多例动物实验中。
[Abstract]:Heart failure (HF) is a serious threat to human health. The most effective treatment for advanced heart failure is a heart transplant and auxiliary artificial heart. Due to insufficient number of heart transplantation, artificial heart gets rapid development. With the increase of the amount of use of the artificial heart, cardiac function caused by recovery phenomenon has aroused great attention however. Has not yet been established to promote the recovery of cardiac function as artificial heart control policy.
Artificial heart pump is a new generation of artificial heart developed by Beijing University of Technology. The goal of this paper is through the interaction of control artificial heart pump and human body, promote the recovery of heart function. Therefore, the establishment of artificial heart pump hierarchical control strategy based on the recovery of cardiac function in order to solve the three problems facing artificial heart pump in the treatment of heart failure. How to determine the best level of auxiliary artificial heart pump; how to meet the circulatory system of blood perfusion and cardiac unloading needs; and how to maintain the stability of the control system of the artificial heart pump. In view of the above questions, three aspects of research papers.
First, the establishment of the circulatory system and artificial heart pump Pi models for artificial heart pump controlled object control strategy. Firstly, establish the circulation system of the lumped parameter model to study hemodynamic mechanism of the circulatory system. Secondly, the establishment of baroreflex system (Baroreflex System) mathematical model to study the baroreflex system on heart rate regulation again. In order to study the characteristics of fluid, artificial heart pump establish artificial heart pump fluid mechanics model. Finally, the establishment of the circulatory system and artificial heart pump Pi combined cycle system model lumped parameter model, baroreflex system mathematical model and artificial heart pump fluid mechanics model Pi, and the effectiveness was studied by numerical simulation method Pi model.
Second, the design of artificial heart pump hierarchical control strategy, promote the recovery of cardiac function in the three to solve the problem of artificial heart pump. Firstly, the design of outer control strategy to determine the best auxiliary horizontal circulation system. Secondly, the design of control strategy to meet the needs of middle circulating blood perfusion and cardiac unloading needs. Control strategy is adopted to reflect the change of heart rate needs blood perfusion of the circulatory system; blood flow index (BAI) aided design to reflect changes in heart unloading. Again, the inner control strategy to maintain stability control design of artificial heart pump system. In the end, according to the conclusion of the three problems of artificial heart pump hierarchical control strategy, and the use of numerical methods, auxiliary effect in vitro method and animal experiment method to study the hierarchical control strategy.
Third. The hemodynamic effects of pulsatile blood change of artificial heart pump caused by the auxiliary and auxiliary model of circulation system. Firstly, the design of artificial heart pump pulse compensation control strategy of artificial heart pump caused by changes of blood pulsation. Secondly, the design of constant speed auxiliary mode, synchronous mode and auxiliary counterpulsation mode three artificial heart pump assisted mode, hemodynamic effects using numerical method to study three kinds of modes on the circulatory system.
Three main conclusions have been obtained in the research work of this paper.
First, the circulatory system and artificial heart pump Pi model can accurately reflect the hemodynamic effects of artificial heart on the circulatory system. On the one hand can accurately simulate the hemodynamic characteristics of circulatory system in heart failure; on the other hand Pi model can accurately simulate the heart pump on the hemodynamics of the circulatory system of workers.
Second, the outer control strategy can determine the optimal level of assisted circulation system, the adjustment time is less than 5S; the middle control strategy can meet the circulating blood perfusion and cardiac unloading needs; the inner control strategy can reduce the uncertainty of internal system and external disturbance effects on stability control of artificial heart pump system, the maximum error is O.lL/min; hierarchical control strategy effectively solves the above three problems in a control strategy, and the system adjustment time is less than 5S, the maximum error is O.lL/min. on the animal experiments show that the hierarchical control strategy can accurately determine the optimal level of experimental animal assisted, and can get the optimal combination between blood perfusion and cardiac unloading demand levels.
Third, the auxiliary artificial heart pump can directly affect the hemodynamic characteristics of the circulatory system. On the one hand, can the circulatory system in the process of compensation assisted blood pulsatile changes the design of artificial heart pump pulsatile blood control, pulsatile artificial heart pump assisted circulation system back to normal. On the other hand, synchronous auxiliary mode and counterpulsation mode can achieve better cardiac unloading, the synchronous auxiliary mode can produce blood while achieving maximum pulsatile heart pressure unloading best; and counterpulsation mode can obtain the minimum at the same time to achieve the equivalent of heart heart volume unloading after load.
The work of this paper has three aspects of innovation of.1, this paper put forward the hierarchical control has reached the optimal artificial heart pump auxiliary level and method of promoting the recovery of cardiac function of.2, the control strategy is established to determine the optimal level of outer auxiliary heart, and as a control variable optimization artificial heart pump; auxiliary flow is put forward for the first time the index for the detection and control of cardiac unloading; middle control strategy can be established to balance the blood perfusion and cardiac unloading needs;.3 control the stability of inner control strategy established to maintain the artificial heart pump system, in vitro experiments, animal experiments and clinical application of the control system can meet the level of cardiac assist, blood perfusion and heart unloading and artificial heart pump control system stability in three aspects of demand, to ensure that the animal and human blood in experimental study The normal operation of the circulatory system. The artificial heart, which uses the control system, has been successfully applied to clinical cases and multiple animal experiments.

【学位授予单位】：北京工业大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：R318.11

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