Using Ballistocardiogram and Impedance Plethysmogram for Minimal Contact Measurement of Blood Pressure Based on a Body Weight-Fat Scale.

Electronic health (eHealth) is a strategy to improve the physical and mental condition of a human, collecting daily physiological data and information from digital apparatuses. Body weight and blood pressure (BP) are the most popular and important physiological data. The goal of this study is to develop a minimal contact BP measurement method based on a commercial body weight-fat scale, capturing biometrics when users stand on it. The pulse transit time (PTT) is extracted from the ballistocardiogram (BCG) and impedance plethysmogram (IPG), measured by four strain gauges and four footpads of a commercial body weight-fat scale. Cuffless BP measurement using the electrocardiogram (ECG) and photoplethysmogram (PPG) serves as the reference method. The BP measured by a commercial BP monitor is considered the ground truth. Twenty subjects participated in this study. By the proposed model, the root-mean-square errors and correlation coefficients (r2s) of estimated systolic blood pressure and diastolic blood pressure are 7.3 ± 2.1 mmHg and 4.5 ± 1.8 mmHg, and 0.570 ± 0.205 and 0.284 ± 0.166, respectively. This accuracy level achieves the C grade of the corresponding IEEE standard. Thus, the proposed method has the potential benefit for eHealth monitoring in daily application.

Assessment of pulse arrival time for arterial stiffness monitoring on body composition scales.

This study presents a system that aims to estimate changes in arterial health status in an unobtrusive way. It might be especially useful in long-term self-monitoring of cardiovascular performance for successful treatment and empowerment of patients. This system applies the electrocardiographic and impedance plethysmographic signals acquired using modified body composition scales for the calculation of pulse arrival time, which is directly related to arterial stiffness. The proposed device was tested in a cohort of 14 subjects. The modified scales were compared to the commercial PulsePen tonometer and the results showed significant relationship between these different devices (rs=0.93, p<0.01). The system also showed the ability to track small pulse arrival time variations induced by paced respiration. These findings suggest that scales evaluating parameters of cardiovascular function have potential to become a convenient device for self-monitoring of arterial stiffness.