Toward Clinically Accurate Continuous Blood Pressure Smart Watch Biosensors Using Equitable Bioimpedance Modality and AI

Current wearable blood pressure monitors using photoplethysmography (PPG) in wrist watches or rings face accuracy issues with darker skin tones, leading to biased AI algorithms and inequitable health monitoring. We propose a smartwatch-integrable, lowpower wearable antenna biosensor measuring bioimpedance (BioZ) changes from radial artery blood flow using radio frequencies (RF) for continuous blood pressure estimation. This non-contact RF BioZ-based approach offers a more equitable solution across diverse demographics. Our device has shown good performance with mean absolute errors (MAE) of 5.67 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 6.05 \text{mmHg}$</tex> for RF BioZ. It meets British Hypertension Society (BHS) and Association for the Advancement of Medical Instrumentation (AAMI) error threshold requirements for grade <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$A /$</tex> passing score for non-cuff-based BP measuring technology, respectively.