Noninvasive Respiratory Effort Detection via Electrical Impedance Tomography
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Solution Overview
Problem
Current methods for detecting patient-ventilator asynchrony, such as ineffective inspiratory efforts, are invasive and difficult to detect accurately using only ventilator waveforms, leading to poor patient outcomes like prolonged ventilation and higher mortality rates.
Innovation Solution
The use of an electrical impedance tomography system to acquire and compare impedance data from dependent and non-dependent lung regions with flow rate, pressure, historical, and stored patterns to non-invasively identify respiratory efforts and asynchronies, allowing for corrective actions to be taken.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive techniques such as esophageal catheter or NAVA are used to detect patient effort, then measurement precision is improved, but device complexity and ease of operation deteriorate due to catheter positioning requirements
Solution Approach 1:
The patent replaces invasive mechanical catheter-based systems (esophageal pressure monitoring, NAVA) with a non-invasive electrical impedance tomography system that uses surface electrodes to measure lung impedance changes. This substitution eliminates the need for internal catheter placement while maintaining the ability to detect patient respiratory effort and identify patient-ventilator asynchrony.
Solution Approach 2:
The patent introduces electrical impedance as an intermediary parameter to indirectly detect patient effort. Instead of directly measuring esophageal pressure or diaphragm electrical activity through invasive catheters, the system measures impedance changes in the lung region through the chest wall, using this intermediary signal to infer respiratory effort and detect asynchrony events.
2Device complexity
If only ventilator waveforms are used for detecting patient effort, then device complexity is reduced, but measurement precision deteriorates leading to high rates of ineffective efforts
Solution Approach 1:
The patent makes the monitoring system multi-functional by integrating both ventilator waveform analysis and electrical impedance tomography measurements into a single system. The EIT system can detect patient effort, identify asynchrony events, and provide feedback for ventilator adjustment, combining multiple detection capabilities in one device rather than requiring separate simple and complex systems.
Solution Approach 2:
The patent implements a feedback mechanism where the EIT system continuously monitors lung impedance changes, compares them against ventilator waveforms and predetermined thresholds, and provides real-time feedback to identify patient-ventilator asynchrony. This feedback loop enables the system to detect ineffective efforts and trigger appropriate responses, improving detection accuracy without requiring complex invasive monitoring.
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 the detection of patient-ventilator asynchronies like ineffective efforts through non-invasive means, reducing the incidence of asynchrony and improving patient outcomes by adjusting ventilator parameters.
Implementation Method 1
an electrical impedance tomography system to acquire and compare impedance data from dependent and non-dependent lung regions
Data Source
AI summary
A method of determining a patient's respiratory effort and related patient-ventilator asynchrony comprises acquiring first impedance data representative of a first region of the lungs of the patient, the first region comprising at least a dependent region of the lungs, during the applied positive expiratory pressure, optionally acquiring second impedance data representative of a second region of the lungs, and comparing the first impedance data with one or more of the second impedance data, a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, historical impedance data of the first region, and stored patterns of impedance data of the first region. Related systems for determining a respiratory effort of a patient are also disclosed.