Noninvasive Cuffless Blood Pressure Measurement by Vascular Transit Time

Blood pressure (BP) is one of the most important physiological parameters that can provide valuable information for personal health care. There are two ways to measure human blood pressure viz. Invasive and noninvasive methods. Though invasive methods have been known to measure BP continuously and accurately but they are extremely inconvenient to use and might cause infection. The widely used cuff-based noninvasive methods are also not very convenient to use especially for injured or obese people and infants. Thus, there has been an unmet need for a convenient noninvasive cuff less BP measurement technique. While cuff less methods to measure BP have been previously studied, most of them were limited to offline processing of captured signals and none have presented an end-to-end prototype. Therefore, in this paper, we present a simple and low-cost fully realized implementation that can measure Blood Pressure immediately after capturing heart activity signals from a user namely PPG (Photo plethysmograph) and PCG (Phonocardiogram). The data is transmitted through a Bluetooth module in the system and results are displayed in a user interactive android application. We compared our results with those measured using a commercial cuff-based digital blood pressure measuring device and obtained encouraging results of about 95% accuracy.