Design and Development of a Wearable Wristband for Measuring Pulse Transit Time (PTT) using Pressure Sensors

Pulse diagnosis using noninvasive methods is a valuable technique in clinical applications. Wearable wristbands that measure pulse transit time (PTT) are becoming increasingly essential devices for diagnosing cardiac activities. While attempts have been made to predict blood pressure using PTT with various algorithms, it has been observed that PTT and its inverse parameter, pulse wave velocity (PWV), can vary over time. PTT can be measured between any two points in the body. An experiment is performed to fix the positioning of the sensors at the radial artery wrist with minimum standard deviation. Pressure sensors are used to capture the wrist pulse signals at the radial artery of the wrist with two different distances. Two pressures are initially tested to capture the PTT with 2.5 cms gap and later PTT is recorded with 4.5 cms gap. 11 participants are used to acquire the wrist pulse data from the designed pressure sensor. The coefficient of variation was computed for the PTT and best possible distance for the sensor is concluded.