Neuromechanical Efficiency Determination During Mechanical Ventilation

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Solution Overview

Problem

Current methods for determining neuromechanical efficiency (NME) in mechanically ventilated patients are inadequate as they often require aggressive interventions like occlusion manoeuvres, which disrupt treatment and provide inaccurate readings during dynamic conditions.

Innovation Solution

A method and apparatus that dynamically determine NME by obtaining samples of airway pressure, patient flow, and electrical activity of respiratory muscles at different levels of ventilatory assist, allowing for accurate NME calculation without disrupting ongoing treatment and using these measurements to control ventilatory assist levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If expiratory occlusion manoeuvres are used to determine NME, then measurement precision is improved, but patient comfort and treatment continuity deteriorate

Engineering Contradiction:

ImproveNME measurement accuracyVSAvoidpatient discomfort and treatment disruption

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary computational model that uses readily available ventilator parameters (airway pressure, flow, volume) and electrical activity of diaphragm (Eadi) signals to estimate NME indirectly, avoiding the need for direct occlusion manoeuvres while maintaining measurement accuracy

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical occlusion manoeuvre intervention with a computational approach using mathematical models and signal processing of existing physiological signals (Eadi, airway pressure, flow) to determine NME without physical disruption to the patient's breathing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If static NME determination during occlusion is performed, then measurement simplicity is improved, but dynamic accuracy deteriorates

Engineering Contradiction:

Improvemeasurement procedure simplicityVSAvoiddynamic NME measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements dynamic NME determination by continuously processing Eadi and ventilator parameters during normal breathing cycles, allowing NME to be updated in real-time across different respiratory phases and ventilatory conditions rather than during static occlusion only

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent enables continuous NME monitoring throughout the entire breathing cycle and across multiple breaths at different ventilatory assist levels, providing uninterrupted assessment of neuromechanical efficiency during dynamic physiological conditions

Inventive Principle:

Principle #20Continuity of useful action

3Measurement precision

If multiple levels of ventilatory assist are used for NME determination, then measurement accuracy is improved, but treatment complexity increases

Engineering Contradiction:

ImproveNME determination accuracyVSAvoidventilation control complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system automatically performs NME determination across multiple ventilatory assist levels using the existing NAVA control structure, where the ventilator independently manages the different assist levels and the NME calculation is performed autonomously without requiring additional manual intervention or complex external control

Inventive Principle:

Principle #25Self-service

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 frequent, accurate determination of NME and respiratory system status during high levels of ventilatory assist, reducing patient discomfort and ensuring safe, effective treatment.

Implementation Method 1

obtain samples of ... an electrical activity of a respiratory muscle of the patient during ventilation of the patient

Methodology Applied

Scientific EffectElectrical activity measurement:

Data Source

PatentUS11331445B2Determination of neuromuscular efficiency during mechanical ventilation

Publication Date: 2022.05.17 MAQUET CRITICAL CARE

AI summary

A method, a computer program and a breathing apparatus relates to determination of at least one physiological parameter including the neuromechanical efficiency [NME] of a patient being mechanically ventilated by the breathing apparatus. This is achieved by obtaining samples of an airway pressure (Paw), a patient flow (Ø), a change in lung volume (V) caused by the patient flow, and an electrical activity of a respiratory muscle of the patient, during ventilation of the patient at a first level of ventilatory assist and a second and different level of ventilatory assist, and determining the at least one physiological parameter, including NME, from the airway pressure samples, the patient flow samples, the samples of the change in lung volume, and the samples of the electrical activity of the respiratory muscle, obtained at the different levels of ventilatory assist.