Design and development of continuous cuff-less blood pressure monitoring devices

Due to the global hypertension epidemic, a convenient, miniaturized, and cuff-less blood pressure (BP) monitoring device is desirable. During the past several years, we have attested various studies to acquire BP indirectly via pulse transit time (PTT) obtained from electrocardiogram (ECG) and photoplethysmogram (PPG). Towards this end, some progress has been achieved but the prospect of designing a device that requires neither a pressure cuff nor cross-body contact of ECG electrodes has been uncharted. In this paper, we present two approaches to determine PTT which open the door to convenient, non-invasive, and cuff-less wearables for continuous BP monitoring at home settings. The first device was designed with contact-electrode ECG and PPG sensors, located on the bicep and the ear; while the second one, which is a wrist-worn device, consisted of a non-contact ECG circuit and a piezoelectric pulse sensor. Results indicated that our novel designs enable next-generation devices, providing essential continuous BP monitoring off-the-clinic for hypertension patients as well as healthy people.