Respiratory Circuit Filter Layout for Cross-Contamination Control

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Solution Overview

Problem

Existing respiratory support systems fail to efficiently manage the contamination of breathing circuits by patients, particularly in the context of medical procedures such as intubation, and the use of single-use respiratory therapy circuits leads to waste and increased costs.

Innovation Solution

A filter arrangement for use in a respiratory support system that includes a humidifier chamber, inspiratory conduit, filter, and patient interface, allowing for re-use of the inspiratory conduit and reducing contamination risk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a humidifier is integrated into a respiratory support system, then patient comfort and lung function are improved through humidified gas delivery, but the risk of microbial contamination and cross-infection increases due to the humidifier chamber acting as a reservoir

Engineering Contradiction:
Improvepatient safetyVSAvoidmicrobial contamination
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and isolates the filter component from the main gas flow path, positioning it downstream of the humidifier chamber. This separation allows the filter to specifically address microbial contamination without interfering with the humidification function, directly resolving the contradiction between maintaining humidified gas delivery and preventing microbial contamination.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a filter as an intermediary component between the humidifier chamber and the patient interface. This filter acts as a mediator that allows the beneficial humidified gas to pass through while blocking harmful microorganisms, thus resolving the contradiction by adding a protective intermediate layer.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple components (humidifier, filters, valves) are integrated into the respiratory support system, then gas delivery functionality and patient comfort are improved, but the complexity of assembly, disassembly, and cleaning increases

Engineering Contradiction:
Improvegas delivery functionalityVSAvoidassembly and cleaning complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the respiratory support system into distinct segmented components: humidifier chamber, filter assembly, patient interface, and tubing. Each component can be independently assembled, disassembled, and cleaned. The filter is positioned as a separate removable component that can be easily accessed and maintained, reducing overall system complexity while maintaining comprehensive gas delivery functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a nested structure where the filter is positioned within the gas flow path but can be independently accessed. The filter assembly is nested between the humidifier chamber and the patient interface, allowing it to be integrated into the compact system structure while maintaining independent serviceability for cleaning and replacement.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Object-affected harmful factors

If the filter is positioned downstream of the humidifier chamber, then microbial contamination of the patient interface is reduced, but the filter may become saturated with moisture affecting its filtration efficiency

Engineering Contradiction:
Improvemicrobial contaminationVSAvoidfiltration efficiency
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent specifies that the filter should be replaced regularly (e.g., daily or per manufacturer instructions) rather than attempted to be cleaned and reused. This copying approach - using a fresh filter for each use period - ensures consistent filtration efficiency without the degradation that would occur from moisture saturation, while still providing the benefit of downstream microbial blocking.

Inventive Principle:
Principle #26Copying

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

The filter arrangement effectively prevents contamination between patients, reduces waste, and lowers operational costs by enabling re-use of the inspiratory conduit.

Implementation Method 1

a filter that is in pneumatic communication with the inspiratory conduit downstream of the inspiratory conduit

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

a heated element downstream of the water source and upstream of the T-piece joint configured to evaporate water into the gas stream

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

a humidifier chamber in pneumatic communication with a gases source, an inspiratory conduit in pneumatic communication with the humidifier chamber downstream of the humidifier chamber

Methodology Applied
Scientific EffectPressure gradient flow: Pressure Gradient

Data Source

PatentEP4289462B1Filter arrangement for use in a respiratory support system
Publication Date: 2026.04.29 FISHER & PAYKEL HEALTHCARE LTD
  • EP4289462B1 patent drawingFigure 1
  • EP4289462B1 patent drawingFigure 2
  • EP4289462B1 patent drawingFigure 3

AI summary

An apparatus or kit for a respiratory support system for delivering humidified gas to a user or patient. The apparatus comprising a humidifier chamber in pneumatic communication with a gases source, an inspiratory conduit in pneumatic communication with the humidifier chamber downstream of the humidifier chamber, a filter that is in pneumatic communication with the inspiratory conduit downstream of the inspiratory conduit, and a patient interface for delivering humidified gas to a user or patient, wherein the patient interface is in pneumatic communication with the filter downstream of the filter, or is configured to be placed in pneumatic communication with the filter downstream of the filter.