Blood Pressure Estimation using a Single Channel Bio-Impedance Ring Sensor.

Area of Science:

• Biomedical Engineering
• Cardiovascular Health
• Wearable Technology

Background:

• Growing need for non-obtrusive, continuous blood pressure (BP) monitoring for cardiovascular disease (CVD) prevention.
• Limitations of current cuff-based BP monitors (bulky, uncomfortable, discrete recordings).
• Challenges with optical photoplethysmography (PPG) wearables, including bias towards lighter skin tones and lower body fat.

Purpose of the Study:

• To develop and evaluate a novel ring-based bioimpedance (Bio-Z) system for continuous BP estimation.
• To assess the feasibility of using a single-channel Bio-Z sensor in a compact wearable device.
• To investigate the effectiveness of frequency domain features from Bio-Z signals for BP prediction.

Main Methods:

• Proposed a compact, ring-based wearable device utilizing a single Bio-Z channel to measure arterial blood flow from the finger's digital artery.
• Extracted 9 frequency domain features from windowed beat cycles of the acquired Bio-Z signals.
• Trained subject-specific regression models using the extracted features for blood pressure estimation.

Main Results:

• The developed ring-based Bio-Z system achieved average mean absolute errors of 4.38 mmHg for systolic BP and 3.63 mmHg for diastolic BP.
• The system demonstrated accuracy consistent with Association for the Advancement of Medical Instrumentation (AAMI) standards.
• The Bio-Z modality showed potential for unbiased blood flow sensing across diverse individuals.

Conclusions:

• A ring-based bioimpedance system is a viable and accurate solution for non-obtrusive, continuous blood pressure monitoring.
• This technology offers a promising alternative to traditional cuff-based methods and biased optical sensors.
• The developed system has the potential to improve cardiovascular disease management through accessible and reliable BP tracking.