Implementation Of Non-invasive Central Aortic Pressure Detection System Based On Blind Identification

Cardiovascular disease has become the largest killer of human health. How to detect and prevent cardiovascular disease effectively has become a major topic need to be solved urgently in the world. As a conventional detection item of clinical diagnosis and treatment, arterial blood pressure can reflect the function of the heart and blood vessels of human body, which means that it has significantly clinical value for cardiovascular disease prediction. Compared to the brachial arterial pressure often used to assess the human body’s blood pressure level, CAP is the lateral pressure of the aortic root, which can predict the occurrence of major cardiovascular events and target organ’s damage more intuitively and effectively. Based on the shortcomings that the current invasive measurement is expensive and damage to the human body, while the noninvasive equipment has low precision and poor portability, this thesis puts forward an one-piece equipment which takes ARM as the core based on blind identification technology and two peripheral pulse wave to estimate CAP to provide a new way for the development of noninvasive CAP detection equipment.In this thesis, the projects’background and significance and relative achievements of former researches were introduced in the introduction. Then the introduction to the basic theory and modeling method of cardiovascular system provides a theoretical basis for the application of blind identification algorithm in the cardiovascular system. The third chapter of this thesis describes the principle of radial pulse wave’s estimation from finger pulse wave. The research of transfer function FIR model between finger pulse wave and radial pulse wave lays a certain foundation for the implementation of the cross-correlation algorithm. The fourth chapter describes the principle of CR algorithm and uses the simulated pulse wave produced by asymmetric "T-Tube" model to analyse the order of FIR model that is used to describe the character of the pulse wave transmitting channels between central artery and peripheral artery. The fifth chapter introduces the implementation process of the one-piece noninvasive CAP detection system based on ARM and evalute the performance of this system through the experiments in the sixth chapter.The identified condition and the method of the determination of system order standing on the basic theories of blind system identification still need further studies. Therefore, this thesis choose to use radial arterial pulse wave and instep arterial pulse wave and four orders FIR model to approximate the pulse wave’s transmission channel from the central artery to the peripheral artery to reconstruct the central aortic pulse wave. Although this system can implement the noninvasive detection of CAP, its accuracy and stability still need to be further studied.