ABSTRACT: Blood pressure (BP) is one the very important and vital parameter in clinical healthcare. Nearly approx. 8 million deaths happen due to high blood pressure. So, it is important to monitor blood pressure every now and then. For prolonged years, for measurement of blood pressure cuff based sphygmomanometer has been one of the gold standard method. Later, cuff-based arterial invasive line has also been used for blood pressure measurement under physician care to access BP. In the recent few years, cuff-based oscillometry is used for BP measurement at home healthcare and remote healthcare which is more convenient and easily accessible. But, it has few setbacks namely - inaccurate results due to movement, discontinuous nature, cuff based is painful, unable to integrate it with mobile application and calibration. Recently, many studies and approach to get BP values using various methods are deeply investigated, where BP values can be obtained through time delay in the pressure wave propagation in vascular system of body. Hence, it paved a way for cuffless, non-invasive blood pressure measurement for both patients and healthy persons. We present a wearable watch which is used to estimate Blood Pressure (BP) in real time with the help of ECG (Electrocardiogram) and PPG (Photoplethysmogram). Firstly get the ECG and PPG data from wrist using ECG electrodes and PPG sensor, which is attached to wearable watch. ECG is electrical activity of heart muscle and PPG is optical activity of heart muscle. Pre-process the ECG and PPG data using suitable filters like notch filter, bandpass filter to remove unwanted noises and cross correlate it. Detect the R peak of ECG and PPG peak using peak detection algorithm based on threshold. Obtain time delay between ECG R peak and PPG peak, which is Pulse Transit Time (PTT). Using ECG and PPG peaks Heartrate is calculated. Then, PTT and Heartrate are the input to model to give an estimation of Systolic BP and Diastolic BP. Challenge is to record ECG data and PPG data simultaneously and process the data, so that peaks are visible to get PTT and in turn to obtain blood pressure readings on wearable watch.

Keywords—Blood Pressure, ECG, PPG, PTT, Signal Processing, Peak Detection.

| DOI: 10.17148/IARJSET.2021.8886