Real-Time Evaluation of Time-Domain Pulse Rate Variability Parameters in Different Postures and Breathing Patterns Using Wireless Photoplethysmography Sensor: Towards Remote Healthcare in Low-Resource Communities

Figures

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  Figure 1. Technical sensor setup (A) sensor placement (B) enlarged view of the sensors, (C) PPG signal extraction and ECG HRV parameter processing with the Kubios HRV App (D) work diagram of the entire system.

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  Figure 2. Postures in the test (A) sitting at 90°; (B) standing; (C) supine. The subjects breathed regularly in standing and supine postures. In sitting posture, the measurement was repeated in regular and deep breathing patterns for comparison.

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  Figure 3. Filtering method diagram of the raw PPG signal. Noise augmentation is shown in red curves.

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  Figure 4. Python algorithm implemented.

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  Figure 5. Boxplot and median analysis for all HRV and PRV indicators derived by ECG and the commercial PPG sensor in the four different positions. Low and high box borders represent the first and third quartiles, respectively. * Symbol represents data outliers.

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  Figure 6. Bland–Altman analysis between PRV and HRV indicators in four physiological statuses, where _PPG and _ECG denote PPG- and ECG-derived results, i.e., PRV and HRV indicators. The x axis represents the average mean values between ECG- and PPG-derived measurements and mean values of the PPG-derived measurement while y axis represents the average difference between ECG and PPG derived measurements.

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  Figure 7. Linear regression analysis between HRV and PRV indicators in four physiological statuses.

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  Figure 8. PPG-based remote healthcare monitoring. (A) Settings for lab tests utilized in this study. The BLE protocol configured using the ATT-GATT standard was implemented between the PPG sensor and the embedded unit. The embedded unit was connected using a standard 3.0 USB protocol. (B) A cloud-based standardized solution for real-world applications for low-resource communities. The sensors send the raw PPG data through IoT for cloud-based processing.