A PMUT-Based Wearable Ultrasound System for Central Blood Pressure Monitoring

Central blood pressure is a more accurate indicator to various cardiovascular diseases compared to the widely used clinical measure of brachial blood pressure. Noninvasive measurement of central blood pressure via ultrasound eliminates the risk associated with arterial catheterization. However, existing ultrasound-based methods, which rely on Bramwell-Hill model, necessitate auxiliary modules or time-consuming algorithms, causing significant inconveniences and extended evaluation time. Furthermore, the high voltage requirement of pulsers presents a challenge for the systems based on conventional transducers in terms of size reduction and application in wearable devices. In response to these challenges, we have developed a compact and low-power-consumption linear probe of piezoelectric micromachined ultrasonic transducers (PMUTs) for non-invasive, real-time, and user-friendly monitoring of central blood pressure. Applying a derived model of Bramwell-Hill model, systolic and diastolic pressures of carotid artery were calculated from the real-time diameter and PWV. The accuracy and reproducibility of the system is validated on 12 subjects. The system shows considerable accuracy and reproducibility on carotid blood pressure measurement. As the system composes PMUT probe and the werable hardware design, the system demonstrates tremenondous potential toward realizing real-time wearable monitoring of central blood pressure.