The Research Of Cuffless And Continuous Blood Pressure Measurement Based On PPG

In recent years, hypertension is an invisible killer, a convenient and effective way to measure blood pressure to prevent and control hypertension has become an urgent need. At present, the main methods to detect blood pressure are intermittent, but Continuous BP measurement is able to monitor ones'BPs in 24 hours one day. It is is helpful for long term high BP patients to supervise the effect of their hypotension drugs. This paper has researched a cuffless and continuous BP measurement method based on photoplethysmograph (PPG), which not only can accomplish continuous measurement, but also can get ride of the trouble of cuff.Based on the linear model of PTT and BP, our system got BP by calculating PTT from bi- electrodes ECG and PPG. We have designed the hardware of PPG and bi-electrodes ECG collection circuits. After conditioning both signals, we got the start point of PTT on ECG-R wave point and the stop point of PTT on PPG characteristic point..After that,we designed the experiments to build the linear relation of PTT and BP by various values obtained through rest and movement states. In this paper, we have 12 health experimental objects, and get the following summary:First, the PTT calculated by PPG first derivation maximum point is better than other methods. Second,SBP-PTT linear relationship is better than DBP-PTT or MBP-PTT.The innovations of our system contains several respects. Firstly, we used sym8 wavelet reconstruction method to condition our signals, which is not used by other authors. Secondly, according to PPG characteristic points, we improved the old first derivation method, and got more accurate values. Lastly, in the calculation of PTT, we optimized the ordinary PTT methods and provides a better way. The advantages of this system is the convenient detections of PPG and ECG.PPG itself is popular in clinic.It is uninvasive and easy to carry,so does the two-electrode ECG.