Variable Resistance Expiratory Valve for Sleep Apnea
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Solution Overview
Problem
Current treatments for obstructive sleep apnea (OSA) and snoring, such as CPAP systems and Provent® Sleep Apnea Therapy, face challenges including poor patient compliance due to discomfort, high airflow rates, and ineffectiveness in mouth breathers, with a need for more comfortable and effective solutions that provide continuous airway pressure during both inhalation and exhalation.
Innovation Solution
A system comprising a mask with a one-way, variable resistance expiratory valve that adjusts resistance over the expiratory phase, a portable air flow generator providing low flow rates (1-20 liters per minute), and a design that eliminates the need for high flow rates, allowing for a more comfortable and effective treatment of OSA and snoring by maintaining airway pressure throughout the breathing cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CPAP systems provide high airflow rates to compensate for mask leaks, then airway pressure is maintained, but patient discomfort increases and compliance decreases
Solution Approach 1:
The expiratory valve incorporates a feedback mechanism where the valve opening degree automatically adjusts based on the detected airway pressure. When pressure drops (indicating potential leakage), the valve opens wider to maintain pressure. When pressure is sufficient, the valve closes more to reduce airflow resistance. This closed-loop feedback eliminates the need for high continuous airflow rates while maintaining therapeutic pressure, thereby improving patient comfort and compliance.
Solution Approach 2:
The expiratory valve transitions from a static fixed-orifice design to a dynamic variable-orifice design. The valve opening degree changes continuously during the expiratory phase based on real-time pressure conditions, allowing the system to adapt to varying breathing patterns and leakage rates without requiring high airflow compensation.
2Device complexity
If fixed orifice resistors are used to provide expiratory resistance, then device simplicity is maintained, but pressure control precision deteriorates
Solution Approach 1:
The expiratory valve employs a dynamic opening mechanism where the valve aperture automatically adjusts during expiration based on pressure feedback. This dynamic adjustment enables precise pressure control throughout the expiratory phase, overcoming the fixed-orifice limitation while maintaining relatively simple valve construction using elastic membranes or shape memory alloys.
Solution Approach 2:
The valve utilizes material property changes (elastic deformation of membranes or phase transition of shape memory alloys) to dynamically alter the opening degree parameter in response to pressure changes, achieving precise pressure control without complex mechanical actuation systems.
3Reliability
If expiratory resistance is increased to maintain airway pressure, then positive pressure is achieved, but exhalation discomfort increases
Solution Approach 1:
The expiratory valve provides time-varying resistance during the expiratory phase by dynamically adjusting its opening degree. Early in expiration when airflow is high, the valve opens wider to reduce resistance and discomfort. As expiration progresses and airflow decreases, the valve gradually closes to maintain airway pressure. This dynamic adaptation eliminates the constant high resistance of fixed-orifice devices while achieving therapeutic pressure maintenance.
Solution Approach 2:
The valve operation follows a periodic pattern synchronized with the breathing cycle, providing low resistance during high-flow periods and high resistance during low-flow periods, optimizing both comfort and therapeutic effect throughout the expiratory phase.
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 improves patient compliance and treatment efficacy by reducing discomfort, maintaining airway pressure, and being effective for both nasal and mouth breathers, while being more compact and less cumbersome than traditional CPAP systems.
Implementation Method 1
providing a first amount of resistance to expiration during an early portion of an expiratory phase of breathing and providing a second, greater amount of resistance to expiration during a later portion of the expiratory phase
Implementation Method 2
providing positive airflow into an airway of the patient during the early portion and providing a second, greater amount of positive airflow into the airway during the later portion
Data Source
Figure 1A~1B
Figure 2
Figure 3A
AI summary
A device (1500) for treating a patient suffering from obstructive sleep apnea or snoring can include an expiratory valve (1502) connected to a manifold. The expiratory valve can include a body portion including a feedback port (1518) configured to be connected to an air flow generator. The expiratory valve can include a plunger (1504) at least partially disposed in the body portion. The expiratory valve can include a pressurizing chamber (1516) positioned between an end of the plunger and an end of the expiratory valve. The pressurizing chamber can be configured to receive air from the air flow generator through the feedback port.