Accelerometer Pulse Detection Using PPG Reference Signal
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Solution Overview
Problem
Existing methods for pulse palpation are unreliable and susceptible to motion artefacts and arrhythmias, particularly when using accelerometers, and require multiple sensor placements, which limits their clinical applicability.
Innovation Solution
A device and method that utilize a photoplethysmography (PPG) signal as a reference to enhance motion robustness in accelerometer-based pulse detection, allowing for single-site sensor placement and improved feature extraction through cross-correlation and dynamic time-warping techniques, reducing the need for ECG electrodes and improving arrhythmia robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If accelerometer-based pulse palpation is used, then manual palpation reliability is improved, but motion artefacts severely restrict clinical applicability
Solution Approach 1:
The patent introduces an intermediary processing system that uses cross-correlation between ECG R-peaks and accelerometer signals, combined with dynamic time-warping algorithms, to distinguish true pulse signals from motion artefacts. This intermediary processing layer filters out motion-related noise while preserving genuine pulse information, enabling reliable pulse detection even during patient movement or resuscitation activities.
2Measurement precision
If ECG electrodes and accelerometer are placed at different sites, then pulse detection performance is improved, but sensor attachment complexity and time consumption increase
Solution Approach 1:
The patent merges the ECG electrode placement and accelerometer placement into a single integrated sensor configuration. By placing both sensors at the same anatomical location (e.g., carotid artery site), the system eliminates the need for separate sensor attachment procedures. The combined sensor unit maintains high pulse detection accuracy through cross-correlation processing while significantly reducing placement complexity and time requirements.
3Adaptability or versatility
If accelerometer signals are used as reference signals in PPG-based pulse palpation, then microcirculation pulse detection is achieved, but robustness to arrhythmias is insufficient
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the correlation between ECG R-peaks and accelerometer signals. When arrhythmias are detected (indicated by abnormal correlation patterns or intervals), the system dynamically adjusts its detection algorithm parameters, such as modifying the cross-correlation window or applying adaptive filtering, to maintain reliable pulse detection despite irregular heart rhythms.
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
Enables reliable, sensitive, and specific detection of pulse and pulse-related information, such as pulse transit time, even under challenging conditions like cardiopulmonary resuscitation, without requiring multiple sensor sites or electrode placement, thus enhancing clinical utility.
Implementation Method 1
an accelerometer (ACC) placed on the skin above the carotid artery can be used to detect the pulse
Implementation Method 2
a photoplethysmography (PPG) signal as a reference to enhance motion robustness
Data Source
AI summary
The present invention relates to a device, system and method for detection of pulse and/or pulse-related information of a patient. To allow a single site solution, which is more robust to motion artefacts and arrhythmias, the device comprises an accelerometer signal input (51) configured to obtain an accelerometer signal acquired by an accelerometer sensor arranged at the patient's skin, a pulse signal input (52) configured to obtain a pulse-related signal of the patient, a patient information input (53) configured to obtain patient information, a model unit (54) configured to generate a model of accelerometer-based pulse palpation from the pulse-related signal using said patient information and context information indicating the context of the acquisition of the accelerometer signal, a feature extraction unit (56) configured to extract one or more features from the accelerometer signal using the generated model and/or from the pulse-related signal, and a detection unit (57) configured to detect the pulse and/or pulse-related information of the patient from the one or more extracted features.