Upstream Humidifier Placement in Pressure Support Systems

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Solution Overview

Problem

Existing pressure support systems face issues with rainout and discomfort due to dry pressurized air, as humidifiers are typically placed downstream of the pressure generating device, leading to increased risk of condensation and bacterial growth within the device and patient circuit.

Innovation Solution

A humidifier is positioned upstream of the positive air pressure device, receiving non-pressurized dry breathing gas and producing a humidified flow, which is then pressurized, reducing the risk of rainout by maintaining relative humidity below 100% throughout the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a humidifier is placed downstream of the pressure generating device, then the breathing gas can be humidified, but the risk of rainout and condensation increases within the device and patient circuit

Engineering Contradiction:

Improvehumidification effectivenessVSAvoidrainout and condensation risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional arrangement by placing the humidifier upstream of the pressure generator instead of downstream. This reversal changes the sequence of operations: breathing gas is first humidified at atmospheric pressure, then pressurized. This inversion eliminates rainout because the gas remains supersaturated throughout pressurization and delivery, only becoming saturated at the patient interface where the therapeutic effect occurs.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The humidifier performs preliminary humidification of the breathing gas before it enters the pressure generator. By adding water vapor to the gas at atmospheric pressure in advance, the system ensures that the gas is already saturated when pressurized, preventing condensation during delivery and reserving the rainout effect for the patient interface where it provides therapeutic benefit.

Inventive Principle:

Principle #10Preliminary action

2Power

If dry pressurized air is delivered to the patient, then the pressure support therapy can be provided, but the patient experiences discomfort and pain due to dried out throat and nasal passages

Engineering Contradiction:

Improvepressure support deliveryVSAvoidpatient discomfort and pain

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent reverses the conventional sequence by delivering humidified gas first and then pressurizing it, rather than pressurizing dry gas and then humidifying. This ensures that the therapeutic humidification effect reaches the patient without being negated by subsequent pressurization, thereby eliminating patient discomfort from dry air while maintaining effective pressure support therapy.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The system changes the humidity parameter of the breathing gas before pressurization. By humidifying the gas at atmospheric pressure first, the water vapor content is increased to therapeutic levels. When the gas is then pressurized, the humidity is maintained, ensuring patient comfort throughout the therapy delivery process.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If the humidifier is placed downstream, then the system structure is simpler, but bacterial growth and device malfunction risk increase due to rainout

Engineering Contradiction:

Improvesystem structureVSAvoidbacterial growth and malfunction risk

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent inverts the conventional downstream humidifier placement to upstream placement. This structural inversion, while maintaining similar component count, fundamentally changes the operational environment to eliminate rainout within the device. By humidifying before pressurization, the system prevents water accumulation that would otherwise cause bacterial growth and malfunction, thereby improving reliability without significantly increasing complexity.

Inventive Principle:

Principle #13The other way round (Inversion)

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

This configuration effectively prevents rainout within the pressure support system and patient circuit, enhancing comfort and reducing the risk of bacterial growth and device malfunction.

Implementation Method 1

a humidifier adapted to increase the amount of water vapor entrained in a supply of non-pressurized breathing gas

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

a positive air pressure device structured to generate a positive pressure flow of breathing gas from the supply of non-pressurized breathing gas

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS8397719B2Pressure support system with upstream humidifier

Publication Date: 2013.03.19 KONINKLIJKE PHILIPS NV

AI summary

A pressure support system (10) comprises a humidifier (20) adapted to increase the amount of water vapor entrained in a supply of breathing gas, and a positive air pressure device (30) fluidly coupled downstream of the humidifier. The positive air pressure device is structured to generate a positive pressure flow of breathing gas from the supply of breathing gas received from the outlet of the humidifier.