A Novel Chest-Based PPG Measurement System.

Area of Science:

• Biomedical Engineering
• Wearable Technology
• Integrated Circuit Design

Background:

• Miniaturization of integrated circuits (ICs) enables advanced body-worn sensors for long-term health monitoring.
• Wearable electrocardiogram (ECG) and photoplethysmogram (PPG) devices have improved patient quality of life.
• Chest-based PPG offers potential for multi-vital sign extraction but requires ultra-high dynamic range (DR) ICs to overcome signal noise.

Purpose of the Study:

• To present a dedicated high DR IC system for wearable chest PPG applications.
• To validate the system's performance using a comprehensive on-body measurement protocol.
• To demonstrate the system's capability in extracting multiple vital signs accurately.

Main Methods:

• Developed a small form factor, high DR IC system integrated on a 20 cm2 PCB board for chest PPG.
• Conducted on-body chest PPG measurements in a workspace environment with 6 adult participants.
• Validated system accuracy by comparing chest PPG data against a standard ECG patch for heart rate (HR) and heart rate variability (HRV) monitoring.

Main Results:

• Achieved > 99.53% HR accuracy with an average absolute deviation (AD) of 0.41 beats per minute compared to ECG.
• Demonstrated > 98.6% HR matching and < 12.8 ms AD in SDNN for HRV monitoring against conventional PPG devices.
• Successfully derived respiration rate and blood oxygen level (SpO2), outperforming reference modalities.

Conclusions:

• The developed high DR chest PPG system provides accurate and reliable vital sign monitoring.
• This technology advances wearable health monitoring, enabling new applications like chest patches for chronic disease management.
• The system's ability to extract multiple vital signs signifies a leap in wearable sensor capabilities.