Physiological Impedance Signal Separation via Matrix Decomposition
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Solution Overview
Problem
Existing physiological monitoring systems using electrical impedance measurements face challenges in accurately separating desired physiological signals from interfering sources such as heart motion and patient movement, leading to inaccurate measurements of respiration rate and other physiological parameters.
Innovation Solution
A method and system that utilize a plurality of transducers to obtain electrical measurement signals, construct a system matrix to define relationships between these signals, and decompose it to separate signals from different physiological and non-physiological sources, allowing for real-time continuous monitoring of ventilation and other physiological activities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single impedance measurement between two electrodes is used, then the measurement system is simple, but the ability to separate desired physiological signals from interfering sources is insufficient
Solution Approach 1:
The patent divides the measurement system into multiple independent measurement channels, each using a different pair of electrodes. This segmentation allows the system to capture different physiological and non-physiological signals simultaneously, enabling subsequent separation of desired respiratory signals from interfering sources through matrix decomposition.
Solution Approach 2:
The patent transitions from a single scalar impedance measurement to a multi-dimensional measurement space by using multiple electrode pairs. This creates a system matrix with multiple rows and columns, adding dimensional information that enables signal separation through mathematical decomposition techniques.
2Measurement precision
If algorithms switch between different pairs of electrodes to avoid interference sources, then signal visibility improves, but the interfering sources remain inseparable from desired signals
Solution Approach 1:
The patent combines measurements from multiple electrode pairs into a unified system matrix, merging information from different measurement perspectives. This combination preserves all signal information simultaneously, allowing mathematical separation techniques to extract desired physiological signals while eliminating interference without losing any measurement data.
3Measurement precision
If electrical impedance tomography techniques are used with a plurality of electrodes, then signal separation capability is improved, but device complexity and computing requirements increase significantly
Solution Approach 1:
The patent extracts and separates only the specific signal components of interest (respiratory signals) from the full measurement matrix, rather than performing complete tomographic reconstruction of the entire conductivity distribution. This extraction approach achieves the necessary signal separation with reduced computational complexity by focusing only on the required physiological parameters.
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 real-time continuous monitoring of physiological activities with low complexity electronics and signal processing, effectively distinguishing desired physiological signals from noise and motion artifacts, even in patients who are comatose, sedated, or experiencing motion.
Implementation Method 1
Electrical Impedance Spectroscopy (EIS) measurements are used to classify and quantify the complex electrical properties of materials, such as those that comprise a region of a human body. These electrical properties are determined by applying an electrical current or voltage, and measuring a response voltage or response current on one or more electrodes
Data Source
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AI summary
A system and method for determining physiological parameters based on electrical impedance measurements is provided. One method includes obtaining electrical measurement signals acquired from a plurality of transducers coupled to a surface of an object and constructing a system matrix to define one or more relationships between the impedance measurement signals. The method also includes decomposing the system matrix to separate the electrical measurement signals.