Design And Implementation Of Blood Pressure Evaluation System Based On Heart Sound Signal

Cardiovascular disease(hypertension,coronary heart disease,etc.)is one of the biggest killers of human life.According to the World Health Organization(WHO),more than 20 million people worldwide die from cardiovascular disease.With the change of people's diet,people with cardiovascular disease are becoming younger and younger.Therefore,early detection and prevention of cardiovascular disease is of great significance to promote people's health.In order to achieve longterm effective monitoring of cardiovascular health of people of all ages,this paper designs and implements an intelligent blood pressure health assessment instrument based on heart sound signals for health parameters such as heart rate,blood pressure,blood oxygen saturation,and dynamic arteriosclerosis index.This article combines hardware system module design,software system module design,and blood pressure calculation module based on heart sound signal to form a blood pressure health assessment system based on heart sound signal.Based on this,an intelligent blood pressure health assessment instrument is designed.The hardware system of the blood pressure health intelligent assessment instrument includes a hardware acquisition module and a hardware processing module,and the application software development of the software platform is implemented based on the hardware system.The hardware acquisition module includes a four-channel heart sound sensor based on silicon material and a finger clip pulse wave sensor.The hardware processing module is an I.MX6 ULLL core board based on ARM Linux processor,and the software platform is based on QT C ++ for application development under the Linux environment.The overall design includes the establishment of the development tool Qt Creator cross-compilation environment,the implementation of signal acquisition,waveform display,and data storage functions.On this basis,the blood pressure(BP),Heart rate(HR),blood oxygen saturation(Sa O2)and pulse wave velocity(PWV)and other commonly used cardiovascular health assessment parameters are comprehensively analyzed,and health scores and related recommendations are given.In terms of blood pressure calculation,two methods for predicting and evaluating blood pressure based on heart sound signals are proposed,focusing on the relationship between heart sound and blood pressure.Method one: Establish a blood pressure prediction model based on support vector regression(SVR),take the second heart sound time series as the feature input,and the corresponding systolic and diastolic blood pressure measured by the electronic sphygmomanometer as the target output.Train the model to obtain the predicted blood pressure.Method two: According to the relationship between blood pressure and heart sound signal,extract the time interval between the first heart sound and the second heart sound peak point and the kurtosis of the second heart sound as features,and linearly fit the systolic and diastolic blood pressure measured by the electronic blood pressure monitor.According to the linear relationship between the time interval between the first heart sound and the second heart sound,the kurtosis of the second heart sound,and the blood pressure,a blood pressure calculation formula based on the heart sound is proposed.The experimental results show that blood pressure has a strong correlation with the time interval between the second heart sound,the first heart sound and the peak point of the second heart sound,and the kurtosis of the second heart sound.Method 1 The blood pressure prediction model based on SVR and the method 2 derived from the blood pressure calculation formula have an average error of less than 5mm Hg and a standard deviation of less than 8mm Hg measured by a commercial electronic sphygmomanometer.The experimental results of both methods meet international standards and can be used for blood pressure Continuous measurement has significant application prospects in some specific medical environments.In conclusion,the blood pressure evaluation system based on the heart sound signal integrates the detection functions of heart rate,blood oxygen concentration,blood pressure,and arteriosclerosis.On the one hand,it can be used for daily home cardiovascular health monitoring and long-term monitoring;on the other hand,it provides the user's heart sound map and pulse wave,which helps doctors make further medical diagnosis of patients with cardiovascular disease.