Oxygen Delivery Valve Control for Ventilator Wastage Reduction
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Solution Overview
Problem
Mechanical ventilators with passive patient circuits experience significant oxygen wastage due to continuous leaks, especially when using bottled oxygen, which is costly and quickly depleted during transport, as only a fraction of the delivered oxygen is inhaled by the patient.
Innovation Solution
A system comprising an oxygen source, a ventilator, a valve, and a computer system that determines gas volumes delivered during breath cycles and controls the valve to only allow oxygen flow during inspiratory phases, minimizing wastage by shutting off oxygen flow during exhalation and accumulating oxygen for delivery during inhalation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a passive patient circuit with continuous exhalation valve leak is used, then CO2 removal and rebreathing prevention are achieved, but oxygen wastage increases significantly
Solution Approach 1:
The patent applies periodic action by switching the exhalation valve between open and closed states based on the patient's breath cycle. The valve closes during inspiration to prevent oxygen wastage and opens during expiration to allow CO2 removal, creating a periodic on-off pattern that synchronizes with the breathing rhythm. This resolves the contradiction by providing CO2 removal only when needed (during expiration) while preventing oxygen wastage during inspiration.
Solution Approach 2:
The patent implements dynamics by transitioning from a static, continuously open exhalation valve to a dynamic valve that changes state based on breath phase detection. The system uses flow sensors and control algorithms to dynamically adjust valve position, opening during expiration for CO2 removal and closing during inspiration to conserve oxygen. This dynamic adaptation resolves the contradiction between continuous CO2 removal and oxygen conservation.
2Quantity of substance
If wall oxygen supply is used in hospital settings, then oxygen availability is ensured, but oxygen wastage is less concerning due to plentiful supply
Solution Approach 1:
The patent applies periodic action by controlling the exhalation valve to open only during expiration phases, creating intermittent rather than continuous oxygen flow through the circuit. This periodic operation reduces overall oxygen consumption while maintaining adequate oxygen availability during inspiration, resolving the contradiction between ensuring oxygen availability and minimizing wastage even when wall supply is available.
3Adaptability or versatility
If bottled oxygen is used during patient transport, then oxygen supply portability is achieved, but oxygen depletion occurs rapidly due to continuous flow requirements
Solution Approach 1:
The patent applies periodic action by delivering oxygen in pulsed intervals synchronized with the patient's breath cycle rather than continuous flow. The exhalation valve closes during inspiration to trap oxygen in the circuit, then opens during expiration to allow CO2 removal. This periodic delivery extends bottled oxygen duration by several fold while maintaining adequate oxygen supply during transport.
Solution Approach 2:
The patent implements preliminary action by pre-filling the patient circuit with oxygen during the expiratory phase before the next inspiration begins. This allows the circuit to act as a reservoir, ensuring oxygen is already available when the patient needs to inhale, thereby extending the effective duration of bottled oxygen supplies during transport.
4Quantity of substance
If continuous oxygen flow is delivered through the ventilator, then oxygen supply to patient is maintained, but FiO2 is diluted by the large bias flow from the exhalation valve
Solution Approach 1:
The patent applies periodic action by controlling the exhalation valve to close during inspiration, preventing the dilution of supplemental oxygen by bias flow. Oxygen delivered during inspiration remains concentrated because the valve prevents mixing with ambient air. During expiration, the valve opens to allow CO2 removal. This periodic control maintains precise FiO2 concentration while ensuring adequate oxygen supply.
Solution Approach 2:
The patent extracts the harmful continuous bias flow component by closing the exhalation valve during inspiration, removing the source of oxygen dilution. This allows the supplemental oxygen to maintain its intended concentration without being mixed with large volumes of ambient air through continuous leakage, thereby preserving FiO2 precision while maintaining oxygen supply.
Data Source
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AI summary
A system (100) for delivering oxygen comprises: an oxygen source (102); a ventilator (104) operatively connected to the oxygen source to receive a supply of oxygen therefrom; a valve (109) having a) an open position in which the ventilator receives the supply of oxygen from the oxygen source and b) a closed position in which the ventilator is not in fluid communication with the oxygen source; a sensor (112) configured to measure breath flow information for the patient; and a computer system (114) to: determine a volume of gas delivered to the patient during a breath cycle of the patient and an inspiratory volume of gas delivered to the patient during an inspiration phase of the breath cycle by using the breath flow information; and provide input to the valve based on the determined volumes, the provided input causing a movement of the valve between the open and the closed positions.