Respiratory Interface Venting With Adjustable Impedance for Quiet CO2 Washout

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Solution Overview

Problem

Existing respiratory therapy devices and patient interfaces suffer from issues such as discomfort, noise, poor fit, and reduced compliance due to inadequate sealing, leading to inefficiencies in treating respiratory disorders.

Innovation Solution

A vent system for respiratory therapy systems featuring slots with specific dimensions and configurations to minimize noise and discomfort, along with a patient interface that maintains therapeutic pressure while allowing exhaled gases to escape, and a vent module with adjustable impedance to reduce noise and vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a vent is provided in the patient interface to allow exhaled gases to escape, then CO2 washout is improved, but noise and discomfort increase

Engineering Contradiction:
ImproveCO2 washout effectivenessVSAvoidnoise and discomfort
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The vent is divided into multiple slots (e.g., 4-16 slots) arranged in a circular pattern around the periphery of the patient interface. Each slot has specific dimensional ratios (length:height ≥ 10:1, width:height ≥ 15:1) designed to minimize turbulence and noise while maintaining effective CO2 washout. This segmentation allows distributed gas release rather than concentrated flow through a single opening.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The slot dimensions are specifically engineered with particular geometric properties (length significantly greater than height, width significantly greater than height) to create localized flow characteristics that reduce turbulence. The slots are positioned at specific locations around the periphery where they can effectively release exhaled gases without directing flow toward the patient's face or causing discomfort.

Inventive Principle:
Principle #3Local quality

2Reliability

If the vent allows free flow of exhaled gases, then CO2 washout is improved, but therapeutic pressure is compromised

Engineering Contradiction:
ImproveCO2 washout effectivenessVSAvoidtherapeutic pressure
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The vent incorporates an adjustable impedance mechanism that can dynamically modify the resistance to gas flow through the slots. This allows the system to adapt the venting characteristics in real-time, balancing CO2 washout requirements with therapeutic pressure maintenance. The adjustable impedance may respond to patient breathing patterns, pressure levels, or CO2 concentration measurements to optimize performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The impedance of the vent can be changed by modifying physical parameters such as slot configuration, adding adjustable restrictions, or changing the effective opening area. These parameter changes allow the system to transition between different operating modes, providing adequate CO2 washout during normal breathing while maintaining therapeutic pressure during pressure support phases.

Inventive Principle:
Principle #35Parameter changes

3Stress or pressure

If the patient interface seals tightly to maintain therapeutic pressure, then pressure delivery is improved, but comfort and compliance decrease

Engineering Contradiction:
Improvetherapeutic pressure deliveryVSAvoiddiscomfort
Core Design Contradiction:
Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The vent distributes exhaled gas release across multiple slots around the periphery, preventing concentrated turbulent flow that would cause discomfort. The segmented design allows the patient interface to maintain a tight seal for effective pressure delivery while providing multiple distributed pathways for comfortable exhaled gas escape, reducing the sensation of stuffiness or pressure buildup.

Inventive Principle:
Principle #1Segmentation

4Stress or pressure

If the vent slots have small dimensions to maintain pressure, then therapeutic pressure is preserved, but CO2 washout effectiveness is reduced

Engineering Contradiction:
Improvetherapeutic pressureVSAvoidCO2 washout effectiveness
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The slot geometry is designed with specific dimensional ratios where the length is significantly greater than the height (length:height ≥ 10:1) and width is significantly greater than height (width:height ≥ 15:1). This creates a slot shape that provides adequate cross-sectional area for CO2 washout while maintaining constraints that preserve therapeutic pressure. The extended length in one dimension allows effective gas exchange without requiring large openings that would compromise pressure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4464358B1Vents for patient interfaces
Publication Date: 2026.04.01 RESMED PTY LTD
  • EP4464358B1 patent drawingFigure 1
  • EP4464358B1 patent drawingFigure 2A
  • EP4464358B1 patent drawingFigure 2B~2F

AI summary

The present invention relates to a vent for a patent interface for delivering respiratory therapy to a patient, the vent comprising a body, the body defining a housing having an opening, the body further defining at least one flow path from a first side of the body to an opposite second side of the body, the vent further comprising a cover having a base portion configured to engage the body and seal the opening, thereby sealing the housing, and a head portion configured to move between a first position or configuration in which the head portion at least partially occludes the at least one flow path and a second position or configuration in which the degree of occlusion is reduced, the vent further comprising an actuator provided within the housing, the actuator configured to move the head portion between the first and second positions or configurations.