Piloted Exhalation Valve for Ventilation Mask
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Solution Overview
Problem
Current ventilator systems with vented patient circuits require excessive gas flow, leading to noise, dryness, and high CO2 rebreathing, causing discomfort and non-compliance in CPAP therapy, while non-vented systems necessitate larger tubing and headgear, increasing bulk and claustrophobia.
Innovation Solution
A nasal pillows mask with a piloted exhalation valve and pressure sensing modality, allowing CO2 to exit without a dual-limb circuit, reducing ventilator flow requirements, and incorporating a heat and moisture exchanger to minimize tubing size and improve comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If vented patient circuits are used to allow CO2 purging through vent openings, then CO2 management is improved, but gas flow requirements increase significantly, creating noise and dryness
Solution Approach 1:
The exhalation valve is extracted from the external circuit and integrated directly into the mask body, allowing CO2-rich exhaled gas to be vented locally at the mask rather than requiring high flow through external vent openings. This extracts the CO2 management function from the main gas flow path, eliminating the need for excessive ventilator flow.
Solution Approach 2:
The piloted exhalation valve acts as an intermediary mechanism between the patient's airway and the external environment. It selectively opens during exhalation to allow CO2-rich gas to escape while remaining closed during inhalation to maintain positive pressure, thereby managing CO2 without requiring continuous high flow through the circuit.
2Object-generated harmful factors
If non-vented circuits are used to reduce gas flow, then noise and dryness are reduced, but tubing size and headgear bulk increase
Solution Approach 1:
The exhalation valve is merged with the mask body as an integrated component rather than a separate external device. This combination eliminates the need for large external tubing and extensive headgear assemblies, reducing the overall volume and bulk of the ventilation system while maintaining non-vented circuit benefits.
Solution Approach 2:
The exhalation function is moved from the external circuit dimension to the mask body dimension. By incorporating the valve within the mask structure, the system achieves CO2 management without requiring large external tubing, effectively transitioning the solution from a circuit-based approach to a mask-integrated approach.
3Object-generated harmful factors
If minimum pressure of 4 cmH2O is maintained in vented circuits to prevent CO2 rebreathing, then CO2 management is improved, but patient comfort deteriorates due to claustrophobia and suffocation feeling
Solution Approach 1:
The exhalation valve transitions from a static always-open vent configuration to a dynamic piloted valve that opens and closes based on breathing phase. During inhalation, the valve remains closed to maintain therapeutic positive pressure without requiring excessive minimum pressure. During exhalation, the valve opens to allow CO2-rich gas to escape, dynamically adapting to the patient's breathing cycle to balance CO2 management with comfort.
Solution Approach 2:
The piloted exhalation valve operates periodically in sync with the patient's breathing cycle, opening during exhalation phases to vent CO2 and closing during inhalation phases to maintain pressure. This periodic operation eliminates the need for continuous minimum pressure maintenance, reducing claustrophobia and suffocation sensations while effectively managing CO2 rebreathing.
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 reduces tubing size, minimizes headgear tension, enhances patient comfort, and allows for a more discrete mask design, reducing tube drag and claustrophobia, while maintaining effective CO2 management and therapeutic pressure delivery.
Implementation Method 1
the piloted valve is opened during the exhalation phase to allow the CO2-rich gas to exit
Implementation Method 2
incorporating a heat and moisture exchanger to minimize tubing size and improve comfort
Data Source
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AI summary
In accordance with the present invention, there is provided a mask for achieving positive pressure mechanical ventilation (inclusive of CPAP, ventilator support, critical care ventilation, emergency applications), and a method for a operating a ventilation system including such mask. The mask of the present invention includes a piloted exhalation valve that is used to achieve the target pressures/flows to the patient. The pilot for the valve may be pneumatic and driven from the gas supply tubing from the ventilator. The pilot may also be a preset pressure derived in the mask, a separate pneumatic line from the ventilator, or an electro-mechanical control. The mask of the present invention may further include a heat and moisture exchanger (HME) which is integrated therein.