Measurement Of Noninvasive Blood Pressure Waveform Based On Radial Artery Simulation Platform

In recent years,cardiovascular disease has become the largest public health problem in the world,the death rate of cardiovascular disease is at the top of the disease death rate and is increasing year by year.The prevention and treatment of cardiovascular disease can’t be delayed.Clinical research shows that the arterial blood pressure waveform can reflect the cardiovascular system function,which is a important index to cardiovascular diseases for the precaution,diagnosis,treatment and prognosis.At present,the existing non-invasive blood pressure measurement methods are still immature and have many defects,which is not conducive to the prevention and treatment of cardiovascular diseases.In this paper,based on the pulse diagnosis idea of oriental medicine,explores the internal relationship between three-dimensional pulse displacement and blood pressure by building a simulation platform of radial artery,establishes a three-dimensional pulse displacement prediction blood pressure waveform model,and studies a new method of noninvasive blood pressure waveform measurement of radial artery.This is of great significance to the prevention and treatment of cardiovascular disease.The results are as follows:(1)Construction,driving and performance analysis of radial artery simulation platform.The platform is comprised of an atrial ventricular simulation module,an aorta simulation module and a radial artery simulation module.Gaussian function model and gamma density function model are selected to synthesize any type of pulse wave,and the accuracy of pulse wave synthesized by the two models is compared and analyzed.Then,the Gaussian function model is selected to quantify and drive the radial artery simulation platform.Three-dimensional pulse displacement and blood pressure waveforms are collected separately by a binocular vision pulse detection system and pressure transmitter respectively.Analysis and detection results show that the radial artery simulation platform is stable and reliable with good repeatability,and can be used as an experimental platform to study the internal relationship between threedimensional pulse displacement and blood pressure.(2)Establish a non-invasive blood pressure waveform measurement model simulating radial artery.The radial artery simulation platform built in this paper can generate multiple types of pulsating flow at the simulated radial artery.The simulated radial artery blood pressure waveform is collected and stored in real time by a pressure transmitter,and the blood pressure waveform is filtered by a low-pass filter.The simulated radial artery three-dimensional pulse displacement is acquired by binocular vision pulse detection system and a series of algorithms such as camera calibration,image preprocessing,feature extraction and stereo matching.Finally,the BP neural network is used to establish a three-dimensional pulse displacement prediction blood pressure waveform model,and the blood pressure waveform collected by the pressure transmitter is taken as a standard to verify the accuracy of the model in predicting blood pressure waveform.The consistency between the predicted blood pressure waveform and the measured blood pressure waveform is analyzed.The Bland-Altman diagram shows that the difference and the mean of the detection results are all distributed within the 95% confidence interval,which verifies that the model can accurately predict the blood pressure waveform from the three-dimensional pulse displacement.(3)Development of wrist fixing device for three-axis movement.The device comprises a palm arm fixing module,an angle adjusting module and an X-Y axis displacement fine adjustment module.The X-Y axis displacement fine adjustment is realized by a single chip microcomputer control system,and the accuracy of the X-Y axis displacement fine adjustment is verified by experimental methods.The device is mainly used for reducing the non-negligible influence of slight arm shaking on the three-dimensional pulse displacement measurement result and adjusting the pulse taking position so that the binocular vision pulse detection system is in an optimal pulse taking state,which is helpful for improving the measurement accuracy of the three-dimensional pulse displacement of the human body.(4)Verify the applicability of BP neural network model in non-invasive blood pressure waveform measurement.The three-dimensional pulse displacement of the left arm of the human body is obtained under the condition of a three-axis motion wrist fixing device,and the systolic pressure and diastolic pressure of the right arm are simultaneously measured by an electronic sphygmomanometer as a standard.Three-dimensional pulse displacement is used as the input layer of the BP neural network to obtain the predicted blood pressure waveform and extract systolic pressure and diastolic pressure.The results show that the average error between predicted systolic pressure and measured systolic pressure is 1.92 mmHg,and the average error between diastolic pressure is 1.87 mmHg.The error results conform to the international standard for accuracy of electronic sphygmomanometer.The experimental results show that the BP neural network model can be used for noninvasive blood pressure waveform measurement.