Respiratory Flow Estimation for Automatic EPAP Adjustment

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Solution Overview

Problem

Existing respiratory therapies face challenges such as discomfort, high cost, complexity, and inefficiency in treating respiratory disorders like Obstructive Sleep Apnea, Cheyne-Stokes Respiration, Obesity Hyperventilation Syndrome, Chronic Obstructive Pulmonary Disease, Neuromuscular Disease, and Chest Wall Disorders, particularly due to upper airway instability and the difficulty in automatically adjusting the EPAP to maintain airway stability.

Innovation Solution

The development of medical devices and methods that estimate respiratory flow rates using a controller with pressure and motor speed sensors, combined with atmospheric data, to adjust therapy settings dynamically and improve comfort, efficacy, and manufacturability, including systems for screening, diagnosis, and treatment of respiratory disorders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual adjustment of EPAP is used to maintain airway stability, then airway patency can be achieved, but device complexity and ease of operation deteriorate due to requiring clinical expertise and time-consuming titration

Engineering Contradiction:
Improveairway stabilityVSAvoidtherapy adjustment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system automatically adjusts EPAP based on real-time detection of upper airway collapse events and respiratory flow patterns, eliminating the need for manual clinical titration. The microprocessor-controlled device self-regulates therapy parameters to maintain airway patency without requiring continuous clinical intervention or expertise.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system continuously monitors respiratory flow and detects upper airway collapse events, using this feedback to automatically adjust EPAP settings. The microprocessor analyzes flow patterns in real-time and modifies therapy parameters dynamically to prevent airway collapse, creating a closed-loop control system that maintains airway stability.

Inventive Principle:
Principle #23Feedback

2Reliability

If manual adjustment of EPAP is used to treat respiratory disorders, then airway stability can be maintained, but ease of operation deteriorates due to requiring clinical expertise and multiple appointments

Engineering Contradiction:
Improveairway stabilityVSAvoidtherapy setup ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The device performs automatic EPAP titration through self-service functionality, where the microprocessor-controlled system independently adjusts therapy parameters based on detected respiratory events. This eliminates the need for clinicians to manually perform titration procedures and reduces the burden on patients requiring multiple adjustment appointments.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary automatic titration during initial device setup and continues to make real-time adjustments throughout therapy. By pre-configuring and continuously optimizing EPAP settings automatically, the system eliminates the need for subsequent manual adjustments and multiple clinical appointments.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If flow sensors are used to monitor respiratory flow, then measurement precision improves, but device complexity and cost worsen due to sensor requirements

Engineering Contradiction:
Improverespiratory flow measurementVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses pressure sensors as intermediary devices to indirectly measure respiratory flow characteristics. By monitoring pressure changes in the respiratory circuit and analyzing flow-related pressure patterns, the microprocessor can detect upper airway collapse events and estimate flow rates without requiring direct flow sensor measurement, thereby reducing device complexity while maintaining diagnostic accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of operation

If automatic EPAP adjustment is implemented, then ease of operation improves by eliminating manual titration, but device complexity worsens due to automation requirements

Engineering Contradiction:
Improvetherapy adjustment easeVSAvoidautomation system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The microprocessor-controlled device provides self-service automatic EPAP adjustment by independently monitoring respiratory flow, detecting upper airway collapse events, and modifying therapy parameters without user intervention. This automation significantly improves ease of operation, allowing patients to use the device without requiring clinical titration expertise or manual adjustments.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The automatic adjustment system continuously monitors respiratory flow and uses real-time feedback from detected collapse events to dynamically adjust EPAP settings. This closed-loop feedback mechanism enables the device to automatically optimize therapy parameters, improving ease of operation while the complexity is managed through efficient microprocessor control algorithms.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS12485241B2Methods and apparatus for respiratory therapy
Publication Date: 2025.12.02 RESMED PTY LTD
  • US12485241B2 patent drawing
  • US12485241B2 patent drawing
  • US12485241B2 patent drawing

AI summary

Methods and apparatus, such as a controller of a respiratory therapy device, generate a signal representing an estimate of flow rate of gas flow from the device. The respiratory therapy device may include a motor-operated blower. The method may include receiving in the controller, signals generated by a set of sensors, including measures of pressure and frequency (e.g., speed) of the motor. The controller may be configured to compute an entrained air density function and generate the estimate signal based on a function of the measures of pressure and frequency, and the entrained air density function. The entrained air density function may apply signals from additional sensors, such as atmospheric pressure, gas temperature, and ambient relative humidity, to compute atmospheric density. Control operations of the therapy device may then be based on the estimated signal, which may be applied to assess accuracy of a signal from a flow sensor.