Assisted Ventilation Synchronization via Diaphragmatic Electrical Signal Calibration

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Solution Overview

Problem

Current assisted ventilation systems face challenges in accurately estimating spontaneous respiratory activity, leading to issues like ventilatory asynchrony and inefficient effort, particularly due to the invasive and complex nature of existing measurement methods, such as oesophageal pressure measurement.

Innovation Solution

An apparatus that utilizes the signal of diaphragmatic electrical activity and ventilatory pressure to calculate calibration parameters during an expiratory pause, allowing for 'tailor-made' regulation of assisted ventilation, thereby eliminating the need for oesophageal pressure detection and improving synchronization with spontaneous breathing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If oesophageal pressure measurement is used to estimate muscle pressure, then measurement precision is improved, but device complexity and ease of operation deteriorate due to invasive procedures and complex data interpretation

Engineering Contradiction:
Improvemuscle pressure estimationVSAvoidmeasurement system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical oesophageal pressure measurement system with an electrical sensing system. Surface electrodes detect electrical signals from respiratory muscles, which are then processed to estimate muscle pressure. This substitution eliminates invasive procedures while maintaining measurement capability through signal processing and calibration algorithms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary calibration process that links easily measurable parameters (surface electrode signals, airflow, ventilator pressures) to the target parameter (muscle pressure). By establishing calibration relationships during a brief occlusion period, the system creates a mapping that allows continuous estimation without direct measurement, simplifying the overall system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If spontaneous breathing activity is accurately estimated, then ventilatory asynchrony is reduced, but measurement and detection difficulty increases with invasive methods

Engineering Contradiction:
Improveventilatory synchronizationVSAvoidspontaneous breathing activity
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces invasive mechanical pressure measurement with non-invasive electrical signal detection. Surface electrodes capture electrical activity from respiratory muscles, providing a reliable indicator of spontaneous breathing effort without the difficulties of oesophageal catheter placement and data interpretation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the patient's own electrical signals from the skin surface to assess their breathing effort. These naturally occurring signals require no special preparation or invasive intervention, making detection simple while providing reliable information about spontaneous breathing activity for synchronization purposes.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If calibration parameters are calculated during expiratory pause, then measurement precision is improved, but loss of time occurs during the pause period

Engineering Contradiction:
Improvespontaneous breathing activity assessmentVSAvoidventilation interruption
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements periodic calibration during scheduled expiratory pauses in the ventilation cycle. Rather than continuous interruption, the system utilizes brief, periodic pause moments to collect calibration data, then resumes normal ventilation. This periodic approach minimizes time loss while achieving sufficient calibration accuracy.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The calibration process is performed in advance during an expiratory pause before the main measurement and control phases. By completing the calibration setup beforehand, the system establishes accurate parameters that can then be used for continuous monitoring and adjustment without requiring repeated interruptions, thus minimizing overall time loss.

Inventive Principle:
Principle #10Preliminary action

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

This approach enables optimized assisted ventilation by accurately assessing and regulating muscle pressure, reducing ventilatory asynchrony and improving patient outcomes by synchronizing ventilator assistance with spontaneous breathing activity, as demonstrated in experimental tests with subjects having acute respiratory insufficiency.

Implementation Method 1

a sensor block (4) connected to the drive block (3) and adapted to provide it with a signal of electrical activity produced by the diaphragm

Methodology Applied
Scientific EffectElectromyographic signal detection: Electrical Resistance

Data Source

PatentEP2827928B1Apparatus for assisted ventilation
Publication Date: 2020.06.17 DRAGERWERK AG
  • EP2827928B1 patent drawingFigure 1
  • EP2827928B1 patent drawingFigure 2A~3C
  • EP2827928B1 patent drawingFigure 4A~4B

AI summary

An apparatus for assisted ventilation (1) comprises at least one ventilatory block (2) connected to and controlled by a drive block (3), and at least one sensor block (4) connected to the drive block (3) and adapted to provide it with a signal of electrical activity produced by the diaphragm. The apparatus further comprises at least one calculation block (5) connected to the drive block (3), to the sensor block (4) and to the ventilatory block (2), the calculation block (5) receiving from the sensor block (4) a signal of diaphragmatic activity (Eadi) and from the ventilatory block (2) a ventilatory pressure signal (Paw) and providing the drive block (30) with calibration parameters (Cal) calculated on the basis of a signal of diaphragmatic electrical activity (Eadi*) and a ventilatory pressure signal (Paw*) upon switching-off said ventilatory block (2) so as to cause an expiratory pause.