Ventilator Control Using EMG Signal Evaluation for Phase Detection
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Solution Overview
Problem
Current ventilator control methods using volume flow signals are inadequate as they require significant patient effort for switch-over and are prone to interference, while electromyogram signals are sensitive to breathing efforts but struggle to distinguish between inhalation and exhalation phases reliably.
Innovation Solution
A method and device that transform electromyogram signals into evaluation signals using a parameter-based evaluation function to unambiguously determine whether the signal corresponds to inhalation or exhalation, allowing for adaptive control signal generation to switch the ventilator between modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If volume flow signals are used to control ventilator switch-over, then the ventilator can be switched between inhalation and exhalation phases, but the patient must make comparatively great effort to bring about a measurable change in volume flow
Solution Approach 1:
The patent replaces the mechanical volume flow measurement system with an electromyogram-based detection system. Instead of measuring actual airflow changes that require patient effort, the system detects electrical signals from muscle activity in the diaphragm and respiratory muscles, allowing switch-over control based on neural intent rather than mechanical output.
Solution Approach 2:
The system detects breathing efforts at an earlier stage by monitoring electromyogram signals that appear before actual volume flow changes occur. This allows the ventilator to be switched over in anticipation of the patient's breathing intent, rather than waiting for the mechanical flow change to become measurable.
2Measurement precision
If electromyogram signals are used to detect breathing efforts, then the start of breathing efforts can be detected very well, but the signal has considerable interference components and very low potentials compared to cardiac signals
Solution Approach 1:
The patent extracts and isolates the specific frequency range and temporal pattern characteristics of electromyogram signals from the mixed physiological signal stream. By separating the EMG component from cardiac and other interference signals through spectral analysis and pattern recognition, the system can detect breathing effort onset while filtering out harmful interference components.
Solution Approach 2:
The system introduces intermediate processing stages including signal filtering, amplification, and feature extraction algorithms that act as mediators between the raw electromyogram signal and the control decision. These intermediaries enhance the weak EMG signals while suppressing interference from cardiac and other sources before the signal is used for ventilator control.
3Measurement precision
If electromyogram signals are used to control ventilator switch-over, then sensitivity to breathing efforts is improved, but reliable distinction between inhalation and exhalation phases cannot be made
Solution Approach 1:
The patent segments the electromyogram signal analysis into distinct phases corresponding to inhalation and exhalation by identifying characteristic temporal patterns and muscle activation sequences. Different muscle groups are monitored and their activation patterns are segmented to determine whether the patient is initiating inhalation or exhalation, thereby recovering the phase information that would otherwise be lost.
Solution Approach 2:
The system adds temporal and spatial dimensions to the EMG signal analysis by monitoring multiple muscle sites and analyzing the time-course of muscle activation. This multi-dimensional approach allows differentiation between inhalation and exhalation phases based on the specific pattern, timing, and location of muscle activity, rather than relying on a single scalar signal value.
Data Source
AI summary
A ventilator control signaling method includes recording an electromyogram signal of values following one another in time and transforming the electromyogram signal into an evaluation signal by applying an evaluation function. An evaluation signal value is assigned to a signal value of the electromyogram signal in the transformation. The evaluation function is determined by a main parameter set that defines which signal value of the evaluation signal is assigned to a particular signal value of the electromyogram signal when the evaluation function is applied in the transformation. A signal value height of the evaluation signal indicates whether the electromyogram signal corresponds to a first state or a second state. A control signal is generated from signal values and is set to switch a ventilator to an inhalation or an exhalation operating mode depending on the state of the evaluation signal. A ventilator is configured to perform the method.