Evaluation of the Accuracy of a New Cuffless Magnetoplethysmography Blood Pressure Monitor in Hypertensive Patients

Abstract

Objective: There is a growing demand for cuffless blood pressure (BP) measurement as an easy alternative to cuff-occlusion-based BP measurement. We assessed the accuracy of a new cuffless, watch-style BP monitor with a magnetoplethysmography (MPG) sensor compared to two standard auscultatory and oscillatory BP monitors. Subjects and Methods: A total of 34 patients with uncontrolled hypertension (systolic BP ≥150 mm Hg or diastolic BP ≥95 mm Hg) were enrolled in the study. BP was measured by two conventional monitors and the new device during the pre-exercise phase, during isometric handgrip exercise, and during the recovery phase (5 min after exercise). The correlation between monitors was assessed using intraclass correlation coefficient (ICC) and Bland-Altman plots. Results: Although two reference monitors produced highly correlated BP measurements, each was differentially correlated with BP measurements obtained by the new MPG monitor. During exercise, the mean difference between systolic BP obtained by the MPG and oscillatory monitors was >7 mm Hg with an ICC of 0.549 (95% CI 0.264-0.746) in systole and 0.737 (95% CI 0.534-0.859) in diastole. The ICC between the auscultatory monitor and the MPG monitor was 0.753 (95% CI 0.559-0.868) in systole and 0.841 (95% CI 0.706-0.918) in diastole after exercise. Bland-Altman plots also indicated that the performance of the new MPG device was very similar to that of the auscultatory monitor. Conclusion: Although the performance of the new MPG monitor was comparable to that of the reference monitors used in this study, improved stability and accuracy are necessary for accurate BP evaluation during dynamic activity.

The 2023 wearable photoplethysmography roadmap

“…Magnetic induction plethysmography. The use of a magnetic field-sensing semiconductor Hall sensor is another alternative to PPG (Kim et al 2018). By placing a series of permanent magnets of 200 G together with some magnetoresistance sensors in the close vicinity of a peripheral artery, e.g.…”

“…(b) A piezoresistive sensor for obtaining the impedance PPG (modified from Luo et al ( 2016 )). (c) A series of Hall sensors for capturing the magnetic induction plethysmography (modified from Kim et al ( 2018 )).…”