Research On Cuffless Continuous Blood Pressure Measurement System Based On ECG Signal And Pulse Signal

The Fifth National Health Service Survey indicates that cardiovascular diseases,especially hypertension,have become the first killer of physical health.Blood pressure is an important physiological parameter to evaluate cardiovascular function and effective measurement of blood pressure is of great significance in cardiovascular disease diagnosis,treatment and prognosis.Blood pressure is affected by many factors such as physiological cycle,physical condition and external conditions,so blood pressure has obvious fluctuation.Besides single measurement is difficult to accurately reflect the level of blood pressure.However,cuffless continuous blood pressure measurement is able to obtain the blood pressure of each cardiac cycle,which is of great significance for disease treatment and medical research.Compared with traditional electronic sphygmomanometer,the device which is based on cuffless continuous blood pressure measurement does not need to use a cuff and a pump.What's more,the device is full-electronic and user-friendly.This paper mainly studies the cuffless continuous blood pressure measurement system by pulse transit time.This method needs to acquire ECG signal and pulse signal simultaneously.Then determine the characteristic points of ECG signal and pulse signal respectively.And pulse transit time is the time difference between the characteristic point of ECG signal and the feature point of pulse signal.At last calculate blood pressure using the relational model of blood pressure and pulse transit time.Specifically,this paper mainly completes the following works:(1)This paper studies the noise sources of ECG signal and pulse signal respectively.Then analysis the characteristics of these noises and put forward the scheme of signal denoising.The results show that the scheme improves the accuracy of blood pressure measurement.(2)The peak point of R wave is usually used as the feature point of ECG signal but a new characteristic point,which is easier to be extracted,is proposed in this paper.(3)Cardiac cycle is applied to estimate pre-ejection period and pulse transit time equals the time difference of the characteristic points minus pre-ejection period,which improves the accuracy of blood pressure measurement.(4)ECG signal is compressed using compressed sensing technology and pulse signal is compressed by the algorithm which uses discrete cosine transform.This compression scheme does not affect the accuracy of blood pressure measurement and prolongs the using time of signal acquisition equipment.(5)An experimental platform is designed and built in this study.A method of parameter calibration is proposed and the characteristic of this method is to alter arm height which induce the change of blood pressure.Experiments verify the feasibility of this method as well as the cuffless continuous blood pressure measurement by pulse transit time when human body is static.