Respiratory Gas Heating Control for Safe High-Temperature Therapy

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Solution Overview

Problem

Existing respiratory support apparatuses do not effectively address the thermal injury risks associated with high-temperature and high-humidity gas flows, particularly for patients with upper respiratory tract infections such as Human Rhinovirus or influenza, and lack safety controls to manage enthalpy and dew-point during and after high-temperature therapy.

Innovation Solution

A respiratory support apparatus with a high-temperature mode that delivers gases at elevated temperatures (above 40°C) and dew-points, controlled by safety algorithms to limit flow rates, duration, and transition to normal mode, using sensors and controllers to maintain safe enthalpy and dew-point levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-temperature gas flows (above 40°C) are delivered to treat upper respiratory tract infections, then treatment efficacy is improved, but thermal injury risk increases

Engineering Contradiction:
Improvetreatment efficacyVSAvoidthermal injury risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts gas flow parameters (temperature, flow rate, duration) based on real-time enthalpy and dew-point measurements. During high-temperature mode, the system delivers gas at temperatures above 40°C for therapeutic effect while continuously monitoring and adjusting parameters to maintain safety margins and prevent thermal injury.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system employs continuous feedback control through enthalpy and dew-point sensors that monitor the gas flow characteristics. The controller uses this feedback to adjust heating elements and flow rates in real-time, ensuring that therapeutic temperatures are maintained while preventing excessive heat accumulation that could cause thermal injury.

Inventive Principle:
Principle #23Feedback

2Reliability

If high enthalpy and dew-point gas flows are used for therapy, then treatment effectiveness is improved, but safety control complexity increases

Engineering Contradiction:
Improvetreatment effectivenessVSAvoidsafety control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The enthalpy and dew-point sensors serve multiple functions: they monitor gas flow characteristics for therapeutic optimization, detect potential safety hazards, trigger alarm conditions, and control the heating elements. This multi-functionality reduces the need for separate monitoring systems while comprehensive safety control.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system automatically adjusts operating parameters based on real-time sensor feedback without requiring manual intervention. The controller autonomously manages heating power, flow rates, and mode transitions, making the safety control system self-regulating and reducing operational complexity.

Inventive Principle:
Principle #25Self-service

3Reliability

If high flow rates are delivered during high-temperature mode, then treatment efficacy is improved, but thermal injury risk increases

Engineering Contradiction:
Improvetreatment efficacyVSAvoidthermal injury risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts flow rates based on real-time conditions rather than maintaining constant high flow. During high-temperature mode, the controller modulates flow rates to deliver therapeutic volumes while preventing excessive heat delivery that could cause injury, adapting to changing patient needs and system conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes multiple parameters simultaneously (temperature, flow rate, duration) to achieve therapeutic effect while maintaining safety. During high-temperature mode, the controller coordinates adjustments across all parameters to ensure that high flow rates deliver sufficient therapeutic gas volume without accumulating excessive thermal energy.

Inventive Principle:
Principle #35Parameter changes

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 apparatus reduces thermal injury risks by safely delivering high-energy gas flows, ensuring safe enthalpy and dew-point levels during and after high-temperature therapy, thereby improving treatment efficacy for patients with upper respiratory tract infections.

Implementation Method 1

The gases flow is typically heated and humidified to aid patient comfort and mitigate drying of the airway

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

a humidifier configured to humidify the gases flow

Methodology Applied
Scientific EffectHumidification: Evaporation

Data Source

PatentEP4178652B1A respiratory support apparatus having a high temperature mode
Publication Date: 2026.04.01 FISHER & PAYKEL HEALTHCARE LTD
  • EP4178652B1 patent drawingFigure 1A~1B
  • EP4178652B1 patent drawingFigure 2
  • EP4178652B1 patent drawingFigure 3

AI summary

According to this disclosure there is provided a respiratory support apparatus configured to provide a gases flow to a patient, the respiratory support apparatus comprising: a flow generator configured to generate the gases flow; a humidifier configured to humidify the gases flow; and a controller. The apparatus is controlled by the controller to function in at least two modes, being a normal mode and a high-temperature mode. In the high-temperature mode the temperature of gases delivered to the patient is higher than the temperature of gases delivered to the patient when in the normal mode. In the high-temperature mode, the controller controls one or more parameters of the gases flow to be different to that in the normal mode, whilst providing higher temperatures. The apparatus is also operative in a cool-down mode in which one or more parameters of the gases flow are controlled. The apparatus includes safety features to ensure the temperature, dew-point, enthalpy, and/or energy of the gases flow do not exceed safe limits.