Ventilator Dyssynchrony Detection via Flow and I/E Signal Analysis

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Solution Overview

Problem

Conventional ventilators often experience dyssynchrony with patients, leading to discomfort and inaccurate parameter measurements, due to issues like fixed backup rates and poor triggering, which are not synchronized with the patient's respiratory efforts.

Innovation Solution

A method for detecting dyssynchrony between a patient and a pressure support system by analyzing patient flow data and an inspiratory/expiratory (I/E) state signal, using criteria such as volume qualified flow slope reversals, incremental tidal volume, absolute tidal volume, and tidal volume during inspiratory phases, to declare and flag dyssynchrony events, allowing for adjustments in the ventilator's operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional ventilators use fixed backup rates and time-based triggering, then the ventilator can maintain consistent operational timing, but dyssynchrony occurs between the ventilator and patient's respiratory efforts

Engineering Contradiction:

Improveventilator timing consistencyVSAvoidsynchronization with patient respiratory efforts

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The ventilator transitions from static time-based triggering to dynamic patient-based triggering by continuously monitoring patient effort signals (flow, pressure, or volume) and adjusting trigger points to match the patient's instantaneous respiratory needs. This allows the ventilator to adapt its timing dynamically while maintaining operational stability through controlled modes.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system implements feedback mechanisms by monitoring patient respiratory parameters (flow, pressure, volume) and using this information to adjust trigger and cycle points. The ventilator compares patient effort signals against threshold criteria to determine when to initiate or terminate breaths, creating a closed-loop control system that synchronizes ventilator operation with patient respiratory efforts.

Inventive Principle:

Principle #23Feedback

2Reliability

If the ventilator operates in assist mode with patient-based triggering, then synchronization with patient effort improves, but inaccurate parameter measurements occur due to dyssynchrony

Engineering Contradiction:

Improvesynchronization with patient respiratory effortsVSAvoidparameter measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary detection and analysis of patient effort signals before initiating ventilator support. By pre-identifying the onset and offset of patient inspiratory efforts through monitored parameters, the ventilator can accurately time its trigger and cycle points to match patient respiratory events, ensuring both synchronization and measurement accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional mechanical time-based control mechanisms with sensor-based detection systems that monitor patient flow, pressure, or volume signals. This substitution enables more precise detection of patient respiratory events and more accurate measurement of respiratory parameters by using electronic sensing and signal processing rather than fixed mechanical timing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the ventilator increases pressure during patient exhalation or decreases pressure during patient inhalation, then patient comfort deteriorates, but dyssynchrony is detected

Engineering Contradiction:

Improvedetection of dyssynchrony eventsVSAvoidpatient discomfort

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system applies preliminary anti-action by detecting dyssynchrony events before they cause significant patient discomfort. Through continuous monitoring of patient effort signals and comparison with ventilator trigger/cycle timing, the system identifies mismatched pressure delivery patterns and can alert clinicians or adjust settings to prevent worsening patient comfort.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The ventilator uses feedback from patient flow, pressure, and volume monitoring to detect when pressure changes are not synchronized with patient respiratory efforts. This feedback mechanism allows the system to identify dyssynchrony events and provide information for adjusting ventilator settings to improve patient comfort and synchronization.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP2401016B1Patient-ventilator dyssynchrony detection

Publication Date: 2020.03.18 KONINKLIJKE PHILIPS NV

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AI summary

A method of detecting dyssynchrony between a patient and a pressure support system includes receiving patient flow data relating to a flow of gas provided to the patient by the pressure support system, receiving an I/E state signal representing a respiratory phase of the patient as determined by the pressure support system, and analyzing the patient flow data and the I/E state signal and declaring a dyssynchrony for a breath based on at least one of the patient flow data and the I/E state signal. The method includes determining whether at least one of a number of predetermined criterion is satisfied based on at least one of the patient flow data and the I/E state signal, and declaring the dyssynchrony for the breath if it is determined that at least one of the number of predetermined criterion is satisfied.