Nasal Ventilation Trigger Algorithm for Neonatal Flow Synchronization

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Solution Overview

Problem

Current nasal ventilation methods for premature newborns face challenges in synchronizing mechanical ventilation with spontaneous respiratory activity due to unstable flow signals from nasal cannulae, leading to inefficiencies and potential harm from false activations and gas bypass.

Innovation Solution

An apparatus that processes respiratory flow signals using a specific algorithm to differentiate between spontaneous and leakage flows, reactivating inspiration only when a normalized signal exceeds a threshold, ensuring synchronized ventilation and adjusting parameters like inspiration and expiration times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If nasal cannulae are used for non-invasive ventilation, then tracheal intubation is avoided and patient comfort is improved, but flow signals become unstable and unreliable for trigger system activation

Engineering Contradiction:
Improvetracheal intubation avoidanceVSAvoidflow signal stability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent segments the respiratory cycle into distinct phases (inspiration and expiration) and applies different processing rules to each phase. During expiration, the system identifies and excludes leakage flow components from the trigger signal calculation, while during inspiration, it uses the full flow signal. This segmentation allows reliable trigger detection despite the presence of leaks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary identification of the expiration phase and leakage flow characteristics before using the flow signal for trigger activation. By预先 characterizing the leakage pattern during expiration, the system can compensate for it during the trigger detection process, improving reliability without requiring invasive measurement.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If flow signal is used for trigger system activation during nasal ventilation, then synchronised ventilation is achieved, but false activations occur due to variable leakage signals

Engineering Contradiction:
Improveventilation synchronizationVSAvoidfalse activation rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic adjustment of the trigger threshold based on the identified respiratory phase. During expiration, the threshold is adjusted to account for expected leakage patterns, while during inspiration, it returns to standard levels. This dynamic adaptation maintains high sensitivity for detecting true breaths while filtering out false triggers from leakage variations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system continuously monitors the flow signal characteristics and uses this feedback to adjust trigger detection parameters in real-time. By analyzing the relationship between flow magnitude and respiratory phase, the system adapts its trigger criteria to distinguish genuine breath initiation from leakage artifacts, reducing false activations while maintaining synchronization.

Inventive Principle:
Principle #23Feedback

3Stress or pressure

If mechanical ventilation is delivered during patient spontaneous expiration, then pressure is applied to the respiratory system, but gas bypasses through the mouth and causes abdominal distension

Engineering Contradiction:
Improveventilation pressure deliveryVSAvoidabdominal distension
Core Design Contradiction:
Stress or pressureVSObject-generated harmful factors

Solution Approach 1:

The system preliminarily identifies the onset of spontaneous inspiration through flow signal detection before delivering the mechanical pressure cycle. By triggering the ventilator cycle at the precise moment of spontaneous inhalation initiation, it ensures that pressure delivery coincides with glottic opening and downward phrenic nerve activity, preventing gastric gas entry and abdominal distension.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The flow signal acts as an intermediary between the patient's spontaneous respiratory activity and the mechanical ventilator cycle activation. This intermediary mechanism ensures precise timing of pressure delivery relative to the patient's natural breath cycle, coordinating mechanical and spontaneous respiration to avoid harmful effects while maximizing ventilation efficacy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP1719536B1Apparatus for nasal ventilation, particularly for flow-synchronised neonatal assisted ventilation
Publication Date: 2011.03.23 GINEVRI SRL
  • EP1719536B1 patent drawingFigure 1A
  • EP1719536B1 patent drawingFigure 1B
  • EP1719536B1 patent drawingFigure 2~3

AI summary

The present invention concerns a method for nasal ventilation and relevant apparatus, particularly for flow-synchronized neonatal assisted ventilation, wherein F(t) is a signal proportional to the ventilation flow, comprising the following steps: (a) inspiration, having a time length Ti, during which air is introduced at an inspiration pressure; (b) expiration, having a time length Te, during which the introduction of air is interrupted; (c) return to step (a); characterised in that it comprises a flow threshold Ftr, and in that during said expiration step (b) the following steps are provided: (b1) a waiting step having a time length γ before the activation of the computation of the leakages; and (b2) a step of computation of the leakages, having a time length δ, so that γ+δ =Te, wherein if a normalized signal F'(t), obtained by a processing by means of an algorithm of the surveyed signal F(t), exceeds the threshold Ftr, a spontaneous respiration activity is detected and the inspiration step (a) is reactivated.