Research On Non-invasive Continuous Blood Pressure Measurement Based On Electrocardiogram And Photoplethysmography Signal

Blood pressure is an important physiological parameter of human body,which can reflect the cardiovascular function of cardiac pump function,peripheral vascular resistance,blood volume and physical state of blood.The blood pressure of the human body is not constant,it will fluctuate distinctly with individual biorhythm emotion and any other kinds of internal and external stimulations.The method of the blood pressure measurement divided into two kinds of intermittent measurement and continuous measurement,intermittent measurement will come out large discrepancy,and can't reflect the changes of cardiovascular function status.By measuring the blood pressure in every cardiac cycle,continuous measurement can let people know blood pressure circadian variation,it is more important in clinical and medical research.Pulse wave transit time(PTT)is a non-invasive continuous blood pressure measurement method,which can realize the measurement of blood pressure for a long time,and has the advantages of simple,effective and comfortable.In this paper,based on the principle of the PTT method,a noninvasive continuous blood pressure measurement method based on ECG and PPG is researched,and a measurement system is designed by this method.Through the acquisition of synchronous ECG signal and PPG signal measurement of PTT,to achieve the measurement of blood pressure.The experiments show that the methods studied in this paper have achieved good results,and carries out experimental analysis,provides a feasible scheme for improving the accurary of blood pressure measurement based on PTT.The main research contents and achievements of this paper are as follows:(1)Aiming at the deficiency of the traditional PTT detection method,a new algorithm is proposed to detect PTT based on waveform time domain feature and dynamic difference threshold: utilizing dynamic difference threshold method to detect the R-waves of ECG,according to the characteristics of the waveform time domain,using R wave to detect the characteristic point of PPG signal,and thus calculate the PTT.The experimental results show that the proposed PTT detection method has the advantages of less calculation,high accuracy and strong anti-interference ability.(2)A noninvasive continuous blood pressure measurement system based on ECG and PPG signal is designed.The hardware of the system includes signal acquisition and microcontroller circuit design,and the experimental system software includes the lower computer and the host computer program.The test results show that the experimental system can collect and store the ECG and PPG signal,can measure the physiological parameters such as PTT and blood pressure.(3)A method of blood pressure estimation using multi parameter model with PTT and the RR interval of ECG signal R wave and the pulse wave characteristic parameter K is proposed to enhance the accuracy of blood pressure measurement.The experimental data of the blood pressure measurement method in this paper are analyzed by using the laboratory test data and the sample data in American MIMIC database.The experimental results showed that compared with PTT single parameter estimation model,the multi parameter based on the PTT and K value and RR interval can improve the estimation of blood pressure.