Non-invasive vascular resistance monitoring with a piezoelectric sensor and photoplethysmogram

Peripheral vascular resistance is known to be a key indicator of the body's efforts to compensate for cardiovascular stresses, but remains very difficult to assess with existing technology. In this work, changes in vascular tone are estimated non-invasively by observing variation in response of a photoplethysmogram and a novel piezoelectric cardiovascular sensor. A simple model of the piezoelectric sensor and underlying artery and tissue is derived to capture trends in relative amplitude and hysteresis between the two sensors, and metrics for estimating vascular resistance based on these trends are proposed. Vascular resistance tracking results are demonstrated to show strong correlation with invasively-measured systemic vascular resistance in swine subjects.