Microneedle-Array-Electrode-Based ECG with PPG Sensor for Cuffless Blood Pressure Estimation

Continuous blood pressure (BP) measurement is essential for real-time hypertension management and the prevention of related complications. To address this need, a cuffless BP estimation technique utilizing biosignals from wearable devices has gained significant attention. This study proposes a feasibility approach that integrates microneedle array electrodes (MNE) for ECG acquisition with photoplethysmogram (PPG) sensors for cuffless BP estimation. The algorithm employed is a baseline multivariate regression model using PTT and RR intervals, while the novelty lies in the hardware design aimed at improving signal quality and long-term wearability. The algorithm’s performance was validated using the Medical Information Mart for Intensive Care (MIMIC) database, achieving a mean error range of ±5.28 mmHg for the SBP and ±2.81 mmHg for the DBP. Additionally, the comparison with 253 measurements from three volunteers against an automated sphygmomanometer indicated an accuracy within ±25%. Therefore, these findings demonstrate the feasibility of an MNE-based ECG with PPG for BP integration for cuffless monitoring of SBP and DBP in daily life. The MIMIC-based evaluation was performed to verify the feasibility of the regression model under ideal public-database conditions. The volunteer experiment, performed with the developed MNE-ECG hardware, served as a separate preliminary feasibility test to observe hardware behavior in real-world measurements.