Nasal Cannula with Flow Restriction Channels for Nitric Oxide Delivery
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Solution Overview
Problem
Current NO delivery systems for ambulatory patients are cumbersome and inefficient, requiring electromechanical parts and sensors, which increase size and limit portability, and often deliver NO too late in the inhalation cycle, leading to exhalation of a significant fraction of the gas, and are not suitable for long-term therapy due to the risk of NO2 production when NO comes into contact with oxygen.
Innovation Solution
A nasal cannula assembly with a deformable-wall reservoir and flow restriction channels that separates NO and oxygen compartments, allowing NO to be delivered efficiently by minimizing contact with oxygen until inhalation, eliminating the need for sensors and electromechanical parts, and ensuring minimal exhalation of NO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pulsed delivery systems with sensors and electromechanical valves are used, then NO can be delivered sequenced to patients, but the system size increases and portability is limited
Solution Approach 1:
The patent removes sensors and electromechanical valves from the system, extracting only the essential function of delivering NO during inhalation by using passive flow restriction channels and patient breathing dynamics to control gas flow timing
Solution Approach 2:
The system uses the patient's own inhalation flow to drive the delivery mechanism, where the patient's breathing creates the pressure differential that opens the flow restriction channel and triggers NO delivery without external sensing or actuation
2Device complexity
If NO is delivered late in the inhalation cycle, then the delivery system is simple, but a significant fraction of NO is exhaled
Solution Approach 1:
The flow restriction channel is positioned and sized to open at the very beginning of inhalation, delivering NO at the optimal moment before the patient's tidal volume fills, ensuring maximum utilization of the delivered gas without requiring complex timing control
3Device complexity
If NO and oxygen are mixed early, then the delivery system is simple, but toxic NO2 is produced
Solution Approach 1:
The system divides the gas delivery into separate compartments: a first compartment delivers oxygen-containing gas, and a second compartment delivers NO-containing gas, with flow restriction channels controlling their separate paths until they mix only at the point of patient inhalation
Solution Approach 2:
The flow restriction channel acts as an intermediary control element that regulates the mixing of NO and oxygen gases, allowing precise control of their interaction to minimize residence time and NO2 formation while ensuring therapeutic delivery
4Device complexity
If long residence time of NO with oxygen is allowed, then the system is simpler, but NO2 concentration increases
Solution Approach 1:
The system minimizes the residence time of NO with oxygen by rushing the mixing process through the flow restriction channel directly to the patient interface, reducing the time available for NO2 formation to below detectable levels while maintaining therapeutic NO delivery
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 nasal cannula assembly effectively delivers NO over extended periods, minimizing anatomical dead volume and NO2 production, providing a portable and efficient solution for ambulatory NO therapy without the need for electronic sensors or processing units.
Implementation Method 1
permitting a passage of gas from the second compartment to the first compartment in a reduced pressure state during an inhalation phase and preventing a majority of flow of the second gas from the second compartment to first compartment in a higher pressure state, during an exhalation phase
Implementation Method 2
a deformable wall forming a part of the boundary between the second compartment and the room atmosphere such that the Compliance of the second compartment is not less than 5 ml/cm H2O while filling but is less than 0.1 ml/cm H2O once the second compartment is full
Implementation Method 3
a first compartment and a second compartment separated by a separation wall, the first compartment comprising a first inlet for introducing a first gas into the first compartment, the second compartment comprising a second inlet for introducing a second gas into the second compartment
Data Source
AI summary
The invention concerns a breathing assistance apparatus having a source of Nitric Oxide in fluid communication with a nasal cannula assembly (10) adapted to deliver gases to a patient comprising a first compartment (1) and a second compartment (2) separated by a separation wall (6); a pair of nasal prongs (5) in fluid communication with the first compartment (1); the first compartment (1) comprising a first inlet (11) for introducing a first gas into said first compartment (1); the second compartment (2) comprising a second inlet (2) for introducing a second gas into said second compartment (2); and the separation wall (6) comprising at least one flow restriction element (35) for controlling the passage of gas from the second compartment (2) to the first compartment (1).