Research On Blood Pressure Detection System Based On Pulse Wave

Blood pressure is an important parameter which can reflect the health of the human cardiovascular system.In clinical,it is based on the blood pressure to diagnose the disease.And the blood pressure will change with the changes of the physical and psychological conditions and the external environment.Long-term continuous monitoring of blood pressure is also important for human health.It can prevent the occurrence of sudden illness.At present,the method of measuring blood pressure by using the pulse conduction time needs to collect multiple physiological signals,which is not suitable for continuous monitoring.In order to achieve a more accurate blood pressure measurement,a blood pressure monitoring system based on pulse wave was established.The blood pressure monitoring system consists of two parts: the pulse wave acquisition system and the PC-based pulse wave processing.The pulse wave acquisition system consists of power management module,pulse wave sensor module,signal conditioning circuit and the main control processor.The pulse wave acquisition system completed the pulse wave signal acquisition and hardware processing through these compositions.After this,the acquired pulse wave signal is transmitted to the host computer.According to the characteristics of the pulse wave signal and its interference,the collected volumetric pulse wave signal is subjected to necessary denoising by wavelet transform.The pulse wave conduction time is obtained by processing the pulse wave signal after eliminating the noise.In this paper,the pulse transit time is extracted from one pulse wave.The pulse wave signal is subjected to quadratic difference to obtain an accelerated pulse wave,and the pulse wave conduction time is extracted from the accelerated pulse wave to establish its relationship with blood pressure.This method solves the problem that the previous blood pressure measurement needs two signals,so it is more convenient for patients to monitor blood pressure.Finally,the data collected from the experiment are used to verify the correlation between the extracted pulse conduction time and blood pressure.Blood pressure is measured by establishing a normalized equation of pulse conduction time and blood pressure.The accuracy of the algorithm is evaluated by analyzing the error between the blood pressure value and the actual blood pressure value.The experimental results show that the pulse duration is highly correlated with systolic blood pressure.The mean and standard deviation of the blood pressure values extracted by this method in the normal blood pressure range(100mm Hg-140 mm Hg)meet the standard range of AMMI,and can achieve daily blood pressure measurement.