Patient Interface Heat Moisture Exchanger Seal

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Solution Overview

Problem

Current respiratory therapy devices and interfaces for treating respiratory disorders, such as CPAP and HFT, face challenges including discomfort, poor fit, and reduced compliance due to obtrusive, aesthetically undesirable, and costly designs that fail to maintain effective seals, leading to reduced efficacy and patient non-compliance.

Innovation Solution

A patient interface with a plenum chamber pressurizable to therapeutic pressures, a seal-forming structure that adapts to the face, a positioning and stabilizing structure to maintain the seal, and a vent structure for continuous gas exhalation, allowing mouth breathing without pressurized air, and incorporating a heat and moisture exchanger to improve comfort and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a seal-forming structure is used to maintain effective seals at therapeutic pressures, then therapy effectiveness is improved, but patient comfort and compliance deteriorate due to obtrusive design

Engineering Contradiction:
Improveseal effectivenessVSAvoidpatient comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent employs a flexible seal-forming structure that adapts to the patient's face contours, providing effective sealing at therapeutic pressures while maintaining comfort. The flexible material allows the seal to conform to facial irregularities without requiring rigid or obtrusive components, thus resolving the contradiction between seal reliability and patient comfort.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent utilizes pressure-activated sealing where the seal-forming structure changes its sealing parameters in response to applied therapeutic pressure. At rest, the seal is comfortable and non-obtrusive; when therapeutic pressure is applied, the seal activates and forms an effective barrier, thereby maintaining both comfort and reliability under different operational conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If pressurized air is delivered continuously to maintain therapeutic pressure, then therapy effectiveness is improved, but patient ability to breathe through mouth deteriorates

Engineering Contradiction:
Improvetherapeutic pressure maintenanceVSAvoidmouth breathing capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patient interface incorporates dynamic flow paths that adapt to patient breathing needs. The system maintains therapeutic pressure in the plenum chamber while allowing dynamic opening of alternative airflow paths when mouth breathing is detected or required, enabling the system to transition between sealed pressurized delivery and open mouth breathing modes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an intermediary mechanism (such as a bypass channel or secondary airflow path) that mediates between the pressurized plenum chamber and the external environment. This intermediary allows therapeutic pressure to be maintained in the nasal pathway while providing an alternative route for mouth breathing, thus preserving both therapeutic effectiveness and breathing versatility.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If heat and moisture exchanger is added to improve comfort and humidification, then patient comfort is improved, but device complexity increases

Engineering Contradiction:
Improvepatient comfortVSAvoidinterface structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The heat and moisture exchanger is integrated into the patient interface assembly, merging the humidification function with the seal-forming structure and plenum chamber. This consolidation provides comfort-enhancing humidification and heating capabilities while avoiding the complexity of separate, standalone components, thus resolving the contradiction between comfort improvement and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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

Enhances patient compliance and therapy effectiveness by providing a comfortable, adaptable, and efficient delivery of pressurized air while allowing mouth breathing and effective humidification, thereby improving respiratory therapy outcomes.

Implementation Method 1

a material configured to adsorb water vapour from gases exhaled by the patient and desorb water vapour into the flow of air at the therapeutic pressure

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

a plenum chamber pressurisable to a therapeutic pressure of at least 4 cmH2O above ambient air pressure

Methodology Applied
Scientific EffectPressurization: Pressurisation

Data Source

PatentEP3976151B1Patient interface with a heat and moisture exchanger
Publication Date: 2023.11.15 RESMED PTY LTD
  • EP3976151B1 patent drawingFigure 1A
  • EP3976151B1 patent drawingFigure 1B
  • EP3976151B1 patent drawingFigure 1C

AI summary

A patient interface may include: a plenum chamber pressurisable to a therapeutic pressure; a seal-forming structure connected to the plenum chamber, the plenum chamber being constructed and arranged to seal with a region of the patient's face; a positioning and stabilising structure configured to provide a force to hold the seal-forming structure in a therapeutically effective position on the patient's head; a vent structure configured to allow a continuous flow of gases exhaled by the patient from an interior of the plenum chamber to ambient; and a material configured to adsorb water vapour from gases exhaled by the patient and desorb water vapour into the flow of air at the therapeutic pressure, the material being positioned within the plenum chamber.