Design Of Noninvasive Continuous Hemodynamic Monitoring System

The detection of hemodynamic parameters is an important index to evaluate cardiac function and is also the basis for clinical diagnosis of cardiovascular diseases.Noninvasive monitoring of hemodynamic parameters has an important application prospect in the prevention and early detection and treatment of cardiovascular diseases.Obtaining hemodynamic parameters from continuous noninvasive blood pressure waveform is a concerned noninvasive detection method.However,traditional blood pressure monitoring cannot directly extract hemodynamic parameters because only a single systolic and diastolic blood pressure can be obtained.The continuous time blood pressure waveform data must be collected to obtain the hemodynamic parameters.The traditional blood pressure measurement with armband compression method cannot obtain the continuous dynamic blood pressure pulse waveform,which makes it difficult to detect the hemodynamic parameters in a non-invasive way.In order to solve this problem,a noninvasive continuous hemodynamic monitoring system is designed by obtaining hemodynamic parameters from the establishment of cardiovascular model.In order to solve the above problems,a noninvasive continuous blood pressure waveform measurement system is designed by combining the photoelectric reflection principle and the vascular unloading principle to realize noninvasive monitoring of hemodynamic parameters.The main research contents of this paper are as follows:(1)In order to solve the problem of difficulty in extracting hemodynamic parameters from blood pressure waveform,a gradient search method is proposed to obtain the mean arterial pressure(MAP)value used in the search phase of calibration system based on the principle of photoelectric reflection and the principle of blood vessel unloading,so as to realize non-invasive continuous hemodynamic monitoring.(2)Based on the analysis of the relationship between hemodynamic parameters,pulse waves and continuous blood pressure,a hemodynamic monitoring model based on the principle of vascular unloading is proposed and the finger sleeve of finger tip pulse pressure and pulse wave signal extraction is designed.The photoelectric pulse wave and finger arterial pressure signal are extracted by the embedded system.(3)In order to calculate the hemodynamic parameters accurately,median filtering and feature point marking algorithm are adopted in the software design of embedded control system to realize the rapid search of MAP values;In addition,Qt integrated development environment is used in the design of upper computer software to design instrument interface and measurement functions.(4)Experimental test and analysis of instrument function.The finger pulse wave and arterial pressure of six subjects are extracted in the laboratory.The parameters of bleeding flow mechanics are calculated by using the designed instrument function software,and compared with the reference value table.The results show that the continuous noninvasive hemodynamic monitoring system designed in this paper can meet the requirements of clinical measurement,its function and stability meet the design requirements,and the hemodynamic monitoring can be realized.