Continuous Beat-to-Beat Cuffless Blood Pressure Monitoring Using Wearable Radial Artery Tonometry.

Abstract

To evaluate the feasibility of continuous beat-to-beat blood pressure (BP) monitoring using radial artery tonometry under controlled dynamic conditions in healthy adults. Twenty healthy adults participated in laboratory recordings that included seated rest and controlled dynamic challenges, including isometric handgrip, cold pressor testing, and inspiratory threshold loading. Beat-to-beat BP was estimated from the tonometry waveform, with periodic cuff-anchored drift correction and automated signal quality indices applied to exclude corrupted segments. Tonometric BP measurements were compared against a Finapres continuous noninvasive reference device. Fourteen recordings met the stability criterion (94.2 $\pm$ 6.3% data retention, approximately 42,000 accepted beats). Agreement with the reference was strong, with Pearson correlation coefficients of 0.933, 0.945, and 0.954 for systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP), respectively. Corresponding mean absolute differences were 7.1 $\pm$ 5.7, 2.5 $\pm$ 2.5, and 3.8 $\pm$ 3.0 mmHg. Radial artery tonometry with periodic drift correction and signal quality filtering demonstrated reliable beat-to-beat BP tracking during extended recordings that included controlled dynamic BP changes. These findings support the feasibility of wearable radial artery tonometry for continuous cuffless BP monitoring and provide a reproducible basis for evaluating long-duration tonometric recordings under physiological stress conditions.