NO Diffuser Tapered Accelerator Minimizes NO2

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Solution Overview

Problem

Existing nitric oxide (NO) delivery systems for inhalation therapy generate excessive nitrogen dioxide (NO2), a toxic gas, especially when using high concentration NO sources, which can exceed safe limits and pose health risks to patients.

Innovation Solution

A device that combines molecular oxygen (O2) and nitric oxide (NO) streams using a diffusing device with a tapered section and an accelerator, which controls the impinging velocity of the NO and O2 streams to minimize NO2 generation, allowing for the safe delivery of high concentration NO without exceeding NO2 limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If high concentration NO source is used, then the volume of NO gas required is reduced and portability is improved, but the amount of toxic NO2 generated increases significantly

Engineering Contradiction:

Improvevolume of NO gas cylinderVSAvoidNO2 generation

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The mixing process is segmented into multiple stages: initial rapid mixing in a controlled zone, followed by gradual diffusion in a tapered section, and final homogenization in a larger chamber. This segmentation allows the high concentration NO to be diluted progressively rather than all at once, controlling NO2 formation at each stage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A carrier gas (typically oxygen or air) is introduced as an intermediary substance between the high concentration NO source and the patient delivery system. This carrier gas facilitates the dilution and transport of NO while controlling the mixing rate to minimize NO2 generation through the reaction 2NO + O2 → 2NO2.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If high concentration NO is delivered into fresh gas flow, then therapeutic efficacy is improved, but toxic NO2 is generated by reacting with O2 in fresh gas flow

Engineering Contradiction:

Improvetherapeutic efficacyVSAvoidNO2 generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The mixing chamber exhibits local quality variations with different zones having different functions: a high-velocity injection zone for rapid NO introduction, a tapered diffusion zone for controlled mixing, and a low-velocity homogenization zone for final blending. Each zone is optimized for its specific function to achieve therapeutic concentrations while controlling NO2 formation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system dynamically changes physical parameters including gas velocity, pressure, and temperature throughout the mixing pathway. The tapered section creates a pressure gradient that drives diffusion, while velocity changes control the residence time of NO and O2 together, thereby controlling the kinetics of NO2 formation.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If NO concentration is increased to reduce cylinder size, then portability is improved, but the formation rate of NO2 increases proportionally to the square of NO concentration

Engineering Contradiction:

ImproveportabilityVSAvoidNO2 formation rate

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The mixing process transitions from a simple linear injection to a three-dimensional diffusion process through the tapered section. This dimensional change increases the surface area for mixing and reduces the concentration gradient in any single direction, thereby reducing the rate of NO2 formation while maintaining effective NO delivery.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 solution effectively reduces NO2 generation to safe levels, even when using high concentration NO sources, thereby ensuring patient safety and enabling the use of smaller NO gas cylinders for increased portability and reduced oxygen dilution.

Implementation Method 1

systems and methods of the present invention can be used to reduce NO2 generated when, for example, being delivered into fresh gas flow in a ventilator breathing circuit

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

Methodology Applied

Scientific EffectGas flow velocity control:

Implementation Method 3

the concentration of NO in the fresh gas flow is about 5 to 80 ppm. Although INO therapy has many benefits, it has been found that when delivering NO into fresh gas flow, nitrogen dioxide (NO2), a toxic gas, can be generated by reacting with O2 in fresh gas flow

Methodology Applied

Scientific EffectChemical reaction control:

Data Source

PatentEP3804793B1Device for diffusing high concentration no with inhalation therapy gas

Publication Date: 2025.05.07 MALLINCKRODT HOSPITAL PRODUCTS IP LTD

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AI summary

Systems of the present invention can enable high concentration NO to be delivered into ventilator breathing circuits, via a diffusing device, without generating undesirably large amounts of NO2.