Positive Pressure Breathing Circuit Gas Wastage Reduction
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Solution Overview
Problem
Existing breathing circuits for positive pressure therapies, such as CPAP, result in wastage of breathing gases during exhalation due to the supply of gases at higher flow rates than necessary, leading to inefficiency and potential oxygen wastage.
Innovation Solution
A positive pressure breathing circuit design that includes an inspiratory member with a non-return valve and a pressure regulation system, allowing stored pressurized oxygen to backfill during exhalation, minimizing wastage by ensuring the oxygen is only released during inhalation and stored during exhalation, with separate tubes for inspiratory and expiratory gases to prevent re-breathing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If breathing gases are supplied at higher flow rates to ensure no shortage during inhalation, then the patient receives adequate breathing gas, but gas wastage occurs during exhalation
Solution Approach 1:
The system performs preliminary action by storing pressurized oxygen in the inspiratory member during exhalation phase, before the next inhalation begins. This pre-storing of gas eliminates the need to supply excess gas continuously, thereby preventing gas wastage while ensuring adequate supply is ready for the next breath.
Solution Approach 2:
Instead of discarding the excess gas capacity during exhalation, the system recovers and stores the pressurized oxygen in the inspiratory member. The non-return valve prevents backflow while allowing the inspiratory member to act as a storage reservoir, recovering what would otherwise be wasted gas potential.
2Device complexity
If a single tube is used for both inspiration and expiration, then the device complexity is reduced, but re-breathing of exhaled gases occurs
Solution Approach 1:
The breathing circuit is segmented into separate inspiratory and expiratory pathways. The inspiratory member and expiratory member are distinct components with separate gas flow paths, preventing mixing of inspired and expired gases. This segmentation eliminates re-breathing while maintaining manageable device complexity.
Solution Approach 2:
The non-return valve acts as an intermediary element that controls gas flow direction between the patient and the breathing circuit. It allows gas to flow in the correct direction (preventing backflow into the inspiratory member) while maintaining the benefits of separate tubing through intelligent flow management.
3Reliability
If pressurized oxygen is supplied continuously, then oxygen availability is ensured, but oxygen efficiency decreases
Solution Approach 1:
The system uses periodic action by supplying pressurized oxygen in a cyclical manner that matches the patient's breathing pattern. Oxygen is stored during exhalation and delivered during inhalation, creating a periodic supply rhythm that improves oxygen efficiency while maintaining reliable availability throughout the breathing cycle.
Solution Approach 2:
The inspiratory member serves itself as a storage reservoir for pressurized oxygen. The system is self-regulating in that the non-return valve automatically prevents backflow and the elastic properties of the inspiratory member naturally facilitate gas storage and release, reducing the need for complex active control mechanisms.
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
This design significantly reduces gas wastage by ensuring oxygen is efficiently used during inhalation and stored during exhalation, maintaining high oxygen efficiency and reducing the need for excess oxygen supply, thereby improving treatment outcomes and cost-effectiveness.
Implementation Method 1
a first non-return valve that is arranged proximally to the second gas entering the inspiratory member, and the first non-return valve is configured to inhibit the exhaled gases from entering the inspiratory member
Implementation Method 2
When all of the stored oxygen gas has been inhaled or entered the patient interface, the breathing gas received by the patient includes the second gas entering the inspiratory member and the first gas in the inspiratory member. During exhalation the first non-return valve closes and the second gas entering the inspiratory member partially 'backfills' the inspiratory member so as to replenish the stored (pressurized) second gas therein.
Implementation Method 3
The inspiratory member may be sized to store a volume of the second gas that is supplied to the inspiratory member at a constant flow rate
Data Source
AI summary
The disclosure relates to a positive pressure breathing circuit and a method for ventilating a patient. The breathing circuit can be used in any type of pressurized breathing therapy including, for example, continuous positive air(way) pressure (CPAP) therapy and bilevel positive air pressure therapy where the inspiratory and expiratory pressures differ. The positive pressure breathing circuit comprises an inspiratory member including a distal portion connectable to a first gas and a proximal portion connectable to second gas wherein the inspiratory member is configured to store a volume of second gas. The inspiratory member further comprises a first non-return valve located proximally to the second gas entering the inspiratory member to inhibit the exhaled gases from entering the inspiratory member. The breathing circuit also comprises an expiratory member and second non-return valve to inhibit exhaled gases from re-entering the patient interface.