The Lumped Parameter Model Research Of Organ Care Technology

Heart transplantation(HT), is the most effective treatment of end-stage heart failure. The number of donor heart is biggest restriction factor of heart transplantation. The high quality heart preservation is the key factor to improve the success rate of transplantation. At present, compared with the commonly used method of cold storage, the normal temperature oxygenated blood method with a beating organ, can significantly extend the heart in vitro survival time and reduce the damage of the heart. The thesis, based on organ care system and combined with the lumped parameter model theory launches a series of research aiming at clarifying the parameters of isolated heart perfusion in vitro cardiac protection mode, as well as the heart function evaluation index under the heart function evaluation mode, further more designing the isolated heart care chamber.Firstly, based on the lumped parameter model theory, the thesis will establish the vitro cardiac protection model to realize the perfusion for the coronary circulation. And according to change the lumped parameter variables, the research confirms the optimal perfusion pressure and flow rate. Secondly, by using the lumped parameter model theory, combined with the physiological basis of the heart, the evaluation of cardiac function is established. The thesis mainly evaluates the cardiac function of left heart and joins the afterload to simulate the heart in the body to perfuse the tissues and organs. By studying the heart function evaluation model the paper discusses the evaluation index of cardiac function, that is, aortic pressure, left ventricular volume and the function for contraction-volume. Last, according to the basic of the numerical studies and concerning on the physiological characteristics of the heart and the realities of situation in vitro protection, the isolated heart care chamber was designed to protect and transport the isolated heart.The results indicate that, first, the research established the vitro cardiac protection model of lumped parameter model, the function of the model is to implement the coronary perfusion of the system, and the numerical results are that perfusion pressure is 45 mm Hg and perfusion flow is 110 ml/min. Second, the evaluation model of cardiac function of lumped parameter model was established which is the assessment of left heart function and explores the ability of evaluation index for the characterization of cardiac contraction of aortic pressure, the characterization of heart reserve ability of left ventricular volume and the function for contraction-volume, when the afterload is increased, simulation results show that the aortic pressure is higher, the volume of the left ventricle is greater. Last, through the basis of theory study, it designs the isolated heart care chamber which can provide recycled blood, fix the heart in a horizontal direction and reduce the damage to the valve and the vessels owing to the design of the connector. In all, the thesis provides a place for the perfusion of the isolated heart and these indicators for validating heart preservation effect are a powerful measure for the effects of protecting isolated heart in vitro heart, which provides a more suitable and heart function more perfect donor heart for clinical before heart transplantation and provides a favorable security for the successful transplantation.