Validation of a wrist-worn dual-sensor applanation tonometry device for blood pressure measurement under rest and stress conditions

Abstract

Wrist-based cuffless blood pressure (BP) monitoring offers potential advantages for longitudinal and ambulatory assessment but has been limited by signal instability and measurement variability, particularly under physiologically dynamic conditions. We evaluated the agreement between a novel wrist-worn blood pressure monitoring device incorporating dual-sensor applanation tonometry (H2-CBP) and reference brachial blood pressure across rest, stress, and recovery conditions. In this prospective validation study, 25 adult participants underwent paired blood pressure measurements using H2-CBP and a validated automated brachial cuff-based device. Measurements were obtained at rest, during a standardized seated lower-limb flexion–extension exercise protocol (5 minutes), and 1 hour after exercise. Agreement was assessed using Bland–Altman analysis, root mean square error (RMSE), and intraclass correlation coefficients (ICC). Linear association was evaluated using Pearson correlation and linear regression analyses. Subgroup analyses were performed by sex and body mass index (BMI). For systolic blood pressure (SBP), the overall mean bias was −3.37 mmHg, with limits of agreement (LOA) from −10.60 to 3.87 mmHg and RMSE of 4.68-5.31 mmHg across conditions. For diastolic blood pressure (DBP), mean bias was −1.64 mmHg, with LOA from −9.97 to 6.68 mmHg and RMSE of 4.01-4.54 mmHg. ICC were consistently high for both SBP and DBP (≥0.94 across all conditions). Strong linear associations were observed between H2-CBP and reference measurements (SBP r=0.972–0.978; DBP r=0.891–0.921; all P<0.001). Agreement metrics were preserved across sex and BMI subgroups. H2-CBP demonstrated robust agreement with reference brachial BP across rest, exercise, and recovery conditions, with low bias, modest error, and high reproducibility. The dual-sensor applanation tonometry design appears to mitigate key limitations of prior single-sensor wrist-based devices. Although not intended to replace diagnostic cuff-based measurements, H2-CBP shows promise as a tool for longitudinal and context-aware blood pressure monitoring in clinical and research settings.Figure 2