Nasal CPAP Nozzle Jetstream Dynamics for Infant Breathing
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Solution Overview
Problem
Conventional CPAP devices for infants require high work of breathing due to continuous flow resistance, which is not accurately replicated by control valves, making them impractical for infants with underdeveloped lungs, as the high momentum gas flow is difficult to overcome during exhalation.
Innovation Solution
A nasal continuous positive airway pressure (nCPAP) device with a generator body featuring non-parallel fluid flow circuits and nozzles that emit low momentum jetstreams, intersecting to create a primary jetstream during inhalation and easily disrupted during exhalation, reducing resistance and work of breathing by allowing exhaled air to flow directly to the exhaust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CPAP devices deliver continuous flow gas to maintain constant pressure, then the patient's airways remain open, but the patient experiences high work of breathing during exhalation due to resistance from incoming gas flow
Solution Approach 1:
The patent applies dynamics by making the gas flow system adaptive rather than static. The device automatically adjusts between delivering continuous flow during inhalation and allowing free exhalation, mimicking natural respiratory mechanics. This dynamic adaptation resolves the contradiction by maintaining reliable pressure support while reducing the work of breathing during exhalation phases.
Solution Approach 2:
The patent changes the flow parameter dynamically based on respiratory phase detection. During inhalation, the system maintains high flow to ensure constant airway pressure; during exhalation, it reduces flow resistance to minimize work of breathing. This parameter change strategy allows the system to satisfy both requirements at different times in the respiratory cycle.
2Adaptability or versatility
If control valves are used to regulate gas flow into the system, then inspiratory and expiratory stages can be accommodated, but the patient still experiences high resistance to exhalation due to valve restriction and incoming gas momentum
Solution Approach 1:
The patent extracts the exhalation resistance problem by providing a separate, dedicated exhalation pathway that bypasses the incoming gas flow and control valve restrictions. The T-piece junction creates an independent exhalation route where patients can exhale freely without opposing forces from the inspiratory gas delivery system, thus maintaining adaptability while eliminating exhalation resistance.
Solution Approach 2:
The T-piece junction acts as an intermediary element that mediates between the pressurized inspiratory gas flow and the patient's exhalation. It allows the high-pressure inspiratory flow to continue undisturbed while providing a low-resistance pathway for exhalation, effectively decoupling the two opposing flow requirements and resolving the contradiction between adaptive control and exhalation ease.
3Stress or pressure
If high momentum gas jet is used to create positive pressure in the patient's lungs, then sufficient pressure support is achieved, but the jetstream is difficult to disrupt during exhalation, increasing work of breathing
Solution Approach 1:
The patent segments the gas flow into separate inspiratory and exhalation pathways using the T-piece junction. The inspiratory jetstream is confined to one branch while the exhalation flow uses a separate branch, allowing the high-momentum jet to maintain lung pressure without interfering with exhalation. This segmentation resolves the contradiction by isolating the high-pressure generation from the low-resistance exhalation requirement.
Solution Approach 2:
Instead of trying to disrupt the high-momentum jetstream during exhalation (the conventional approach), the patent inverts the strategy by providing a parallel exhalation pathway that bypasses the jetstream entirely. This inversion allows the jetstream to maintain its high momentum for pressure support while patients exhale through the alternative low-resistance path, eliminating the work of breathing contradiction.
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 device minimizes the work of breathing for patients by reducing resistance during exhalation, making it more practical for infants and neonates by ensuring a lower momentum jetstream that is easily disrupted, thus enhancing respiratory synchrony and comfort.
Implementation Method 1
The momentum of the gas jet acting over the area of the conduit creates a positive pressure inside the patient's lungs, in accordance with known jet pump principles.
Implementation Method 2
It has been theorized that due to the coanda effect, the expiratory airflow causes the nozzle flow to deflect, thus triggering a fluidic flip of the airflow from the nozzle.
Data Source
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AI summary
A nasal continuous positive airway pressure (nCPAP) device for use with an nCPAP system, characterized in that: a generator body (30) defines a patient side (36) and an exhaust side (38), and forms first and second fluid flow circuits each including a tube (42) defining a passageway (44a), wherein one or both of the first and second fluid flow circuits includes three or more nozzles (50a, 50b) fluidly connected to the passageway, each of the nozzles extending from an inlet end (52) to an outlet end (54) having a reduced diameter as compared to the inlet end.