Multichannel PPG Sensor for Unsupervised Pulse Arrival Time Measurement
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Solution Overview
Problem
Current non-invasive techniques for measuring pulse wave velocity (PWV) require trained medical staff and are not suitable for large-scale ambulatory and follow-up studies, with the reliability of some methods being questioned.
Innovation Solution
A sensor device using a photoplethysmographic (PPG) multichannel sensor that measures PPG signals, extracts features, selects a subset of signals, and processes them to determine pulse arrival time (PAT), combined with electrocardiography (ECG), impedance cardiography (ICG), and phonocardiography (PCG) signals to estimate PWV continuously in a fully unsupervised manner, reducing the need for skilled supervision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional PWV measurement methods (COMPLIOR, SphygmoCor, Vicorder, PulsePen) are used, then measurement reliability is improved, but the need for trained medical staff increases and ease of operation deteriorates
Solution Approach 1:
The system performs automatic PWV measurement without requiring trained medical staff. The multichannel PPG sensor automatically captures multiple PPG signals, the processing unit automatically extracts features and selects subsets of signals, and the system automatically determines PAT values and calculates PWV, enabling unsupervised operation
Solution Approach 2:
The system divides the measurement process into multiple independent PPG signal channels, each capturing pulse wave information from different locations. This segmentation allows the system to process multiple signals simultaneously and automatically identify the most representative ones for PWV calculation
2Ease of operation
If automated PWV measurement methods (Arteriograph) are used, then ease of operation is improved, but measurement reliability deteriorates
Solution Approach 1:
The system replaces the brachial cuff inflation method with a multichannel PPG sensor that optically detects pulse waves at multiple locations simultaneously. This substitution maintains automation while improving reliability through direct pulse wave analysis rather than indirect pressure measurements
Solution Approach 2:
The system transitions from single-point pressure measurement to multi-point simultaneous pulse wave detection. By measuring PPG signals at multiple locations and using feature extraction and clustering algorithms, the system achieves both automation and improved measurement reliability
3Ease of operation
If multi-channel PPG sensor with feature extraction and clustering is used, then ease of operation is improved through automation, but device complexity increases
Solution Approach 1:
The system pre-defines the number of PPG signal channels and the feature extraction parameters before measurement. The clustering algorithm parameters and distance criteria are predetermined, allowing the system to automatically process signals without complex real-time decision-making, thus reducing operational complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method allows for reliable and consistent measurement of central pulse wave velocity, correlating well with established methods like COMPLIOR, and can be integrated into a chest belt for ambulatory PWV assessment, facilitating its use in large-scale studies.
Implementation Method 1
a photoplethysmographic (PPG) multichannel sensor formed from a plurality of PPG sensor channels and being adapted to measure a set of PPG signals
Data Source
AI summary
A method for measuring and determining a pulse arrival time (PAT) value of a user using a sensor device having a photoplethysmographic (PPG) multichannel sensor formed from a plurality of PPG sensor channels and being adapted to measure a set of PPG signals, each PPG signal being measured by one of the PPG sensor channels when the multichannel PPG sensor is in contact with the user; having: measuring the set of PPG signals; extracting a plurality of features from each of the measured PPG signals; selecting a subset from the set of PPG signals based on the extracted features; and processing the selected subset of PPG signals to determine the PAT value. The disclosed sensor and method can be embedded into a chest belt and do not need skilled supervision. They can represent a potential candidate for the implantation of PWV measurement campaigns in the ambulatory setting.