Adaptive Respiratory Circuit Compensation for Tubing Pressure Drop

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Solution Overview

Problem

Respiratory therapy devices face limitations in responsiveness and stability due to transport delays in pressure wave propagation through tubing, leading to pressure drops that affect the precision and timing of gas parameter delivery.

Innovation Solution

A system comprising a pressure generator, sensors, and processors that estimate and compensate for pressure drops by adjusting gas parameters in real-time, using a parameter-based model to dynamically manage the therapy session and improve device responsiveness and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pressure support is delivered through tubing to the patient interface, then the therapy can be delivered to the airway, but transport delay causes pressure drop and reduces responsiveness and stability

Engineering Contradiction:

Improveresponsiveness and stability of respiratory therapy deviceVSAvoidtransport delay of pressure wave through tubing

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary action by estimating the pressure drop caused by transport delay before it affects the therapy delivery. The processor continuously estimates the pressure drop through the tubing based on measured pressure and flow data, and proactively compensates by adjusting the target pressure setting. This allows the system to anticipate and correct for the delayed pressure wave effect, maintaining responsiveness and stability despite the physical transport delay through the patient interface tubing.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If pressure is increased to compensate for pressure drop, then delivery precision improves, but system stability may deteriorate due to feedback delays

Engineering Contradiction:

Improveprecision of gas parameter deliveryVSAvoidstability of pressure control system

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The system implements continuous feedback by measuring actual pressure and flow at the patient interface, estimating the pressure drop through the tubing, and comparing this with the target pressure. The processor uses this feedback loop to dynamically adjust the pressure support level, ensuring precise delivery while maintaining stability. The feedback mechanism allows the system to respond to actual conditions rather than relying on predetermined compensation values.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system applies dynamic adjustment of pressure parameters based on real-time estimation of transport delay effects. Rather than using fixed compensation values, the processor continuously updates the pressure drop estimation and adjusts the target pressure dynamically. This dynamic approach allows the system to adapt to changing flow conditions and tubing characteristics, maintaining precision without causing instability from rigid over-compensation.

Inventive Principle:

Principle #15Dynamics

3Speed

If transport delay is reduced by shortening tubing, then responsiveness improves, but device complexity and functionality are compromised

Engineering Contradiction:

Improveresponsiveness of pressure deliveryVSAvoidtubing configuration and system design

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The system changes the parameter being controlled from physical tubing length to computational pressure drop estimation. Instead of modifying the physical configuration of the tubing to reduce transport delay, the system maintains the necessary tubing length for proper device functionality and compensates through parameter adjustment. The processor estimates and compensates for the pressure drop caused by the tubing, allowing the system to maintain both adequate tubing length for functionality and high responsiveness through computational compensation.

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

Enhances the quality, responsiveness, and stability of respiratory therapy by accurately compensating for pressure drops and maintaining precise gas parameter delivery, even during load disturbances and changes in the therapy session.

Implementation Method 1

a pressure generator configured to generate a pressurized flow of breathable gas for delivery to the airway of the subject

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

The subject interface causes a pressure drop between the output of the pressure generator and the point of delivery during delivery of the pressurized flow of breathable gas

Methodology Applied

Scientific EffectPressure drop: Pressure Drop

Data Source

PatentUS10668236B2Adaptive patient circuit compensation with pressure sensor at mask apparatus

Publication Date: 2020.06.02 KONINKLIJKE PHILIPS NV

AI summary

Systems and methods for providing respiratory therapy overcome various effects of transport delay within tubing of a respiratory therapy device by virtue of estimating and compensating for, e.g., a pressure drop in such tubing.