Non-Invasive Ventilation Flow Paths for Dead Space Flushing
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Solution Overview
Problem
Conventional non-invasive ventilation therapies face challenges such as user intolerance to high pressures leading to skin breakdown, discomfort, and poor compliance due to high mask sealing forces, along with issues like gastric distention and internal tissue damage from elevated pressures.
Innovation Solution
A system with a control assembly that dynamically adjusts the resistance in the primary flow path based on pressure changes within the patient interface, incorporating a movable member to manage gas flow through a primary and flushing flow path, ensuring optimal gas delivery and reducing pressure on the patient's skin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas flow is increased through the primary flow path to meet patient demand, then ventilation effectiveness is improved, but dead space accumulation increases
Solution Approach 1:
The gas flow path is segmented into two separate pathways: a primary flow path (PFP) for delivering gas to the patient and a flushing flow path (FFP) for clearing dead space. This segmentation allows independent control of ventilation delivery and dead space removal, resolving the contradiction by directing different portions of gas flow through different paths based on their specific functions.
Solution Approach 2:
A portion of the gas flow acts as an intermediary flushing flow that travels through the FFP to clear accumulated dead space from the PFP. This intermediary flow prevents harmful CO2 accumulation while the main ventilation flow continues through the PFP, allowing both ventilation effectiveness and dead space management to be achieved simultaneously.
2Loss of substance
If a flushing flow path is added to reduce dead space, then dead space removal is improved, but device complexity increases
Solution Approach 1:
The gas source and control assembly serve multiple functions: they provide both the primary ventilation flow through the PFP and the flushing flow through the FFP. By making the gas delivery system multi-functional, the patent avoids adding separate complex subsystems while still achieving effective dead space removal through the integrated FFP.
Solution Approach 2:
The flushing flow path is merged with the primary flow path at the patient interface, where both flows combine to deliver ventilation. This merging allows the system to use a unified patient interface design while incorporating the dead space flushing function, thereby reducing overall device complexity compared to having completely separate systems.
3Speed
If high velocity flow is used in the flushing flow path to clear dead space, then dead space flushing effectiveness is improved, but energy consumption increases
Solution Approach 1:
The flushing flow operates in a periodic manner, being activated during expiratory phases when the patient is not inhaling. This periodic operation allows the system to achieve effective dead space clearing with high-velocity pulses while minimizing overall energy consumption by not maintaining continuous high-velocity flow. The control assembly timing the FFP activation to coincide with expiratory periods optimizes the balance between flushing effectiveness and energy use.
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 system enhances patient comfort by minimizing skin breakdown and discomfort while maintaining effective alveolar gas exchange, improving compliance by reducing high-pressure side effects.
Implementation Method 1
Increased flow through the FFP may have a high velocity (especially relative to the flow through the PFP). Gas delivered through the FFP may be used to flush dead space.
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D~2E
AI summary
Systems and methods for non-invasive ventilation are provided. The systems may include a gas source that provides breathing gases to a patient through one or more of a primary flow path (PFP) and a flushing flow path (FFP). The system may include a control assembly configured to open and restrict gas flow through the PFP. When the PFP is open, a significant portion of the gas flows through the PFP while the remaining gas flows through the FFP. When the PFP is restricted, a significant portion of the gas flows through the FFP. Increased flow through the FFP may have a high velocity (especially relative to the flow through the PFP). Gas delivered through the FFP may be used to flush dead space. One or both flow paths may contribute to inspiratory positive airway pressure (IPAP), expiratory positive airway pressure (EPAP), and/or positive end expiratory pressure (PEEP).