| The impact of cardiovascular and cerebrovascular diseases on human health is currently increasing.Some common cardiovascular and cerebrovascular diseases,such as hypertension,arteriosclerosis,and other diseases,have become the important risk factors for human health.The occurrence of such cardiovascular and cerebrovascular diseases is usually accompanied by a series of changes in hemodynamic parameters.Once these parameters change,they will affect the blood supply and material exchange between organs and tissues,and then directly threaten human health.The common carotid artery is an important artery channel between the brain and the heart.Collecting and analyzing the hemodynamic information of its upstream and downstream vascular beds plays an important role in the prevention of cardiovascular and cerebrovascular diseases.However,in order to achieve the prevention and early diagnosis of such diseases,the traditional clinical medical technology often needs high cost,and the operation is relatively complicated.In addition,the complex blood environment will also have a certain impact on the research of hemodynamic parameters.Therefore,in order to overcome the above shortcomings,a set of in vitro experiment platform that can accurately simulate arterial characteristics of the downstream vascular beds of the common carotid artery is usually required.It can be used to reproduce hemodynamic parameters in the physiological range in vitro,and provide scientific basis for further research on the relationship between the occurrence of cardiovascular and cerebrovascular diseases and the hemodynamic parameters.To achieve the above research,in this thesis,firstly,the information of blood pressure and flow at the common carotid artery from the subjects as in vivo is obtained.According to Wormersley hemodynamics theory and the relationship between the blood pressure gradient and the blood flow under the condition of pulsatile blood flow,Fourier transform is used to process the blood pressure and flow data,then modeling analysis is implemented according to the vascular input impedance,which can describe the arterial characteristics of the downstream afterload.Secondly,based on the similar relationship between the arterial network and the electrical network,a five-element elastic cavity mathematical model is built to simulate the characteristics of the downstream vascular bed of the common carotid artery,and the model is analyzed and verified.Finally,according to the results of the above work,an in vitro experiment platform that can simulate the characteristics of the downstream vascularbed of the common carotid artery is established.The in vitro experiment platform is mainly composed of a centrifugal pump,which can simulate the process of left ventricle pumping,elastic chamber and resistance valve that can simulate the compliance and resistance of blood vessels,the one-way valve to prevent blood backflow,a STM32 microcontroller,which can control the output working mode of the centrifugal pump,and the pressure sensor for pressure measurement.The in vitro experiment system can simulate the arterial hemodynamic information under different conditions according to the requirements,because pulse width modulation is used to control the centrifugal pump in the system,so the working mode of the centrifugal pump can be controlled by changing the duty cycle of working level,and then the blood pressure and flow under different physiological conditions can be simulated.The experimental results also show that the simulated arterial pressure and flow are within the physiological range.Therefore,this in vitro circulatory system can be used as a reliable experiment platform to study the hemodynamics of the downstream vascular beds of the common carotid artery. |
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