Pneumatic Single-Lumen Gas Conserver Double Pulse Prevention
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Solution Overview
Problem
Single-lumen oxygen-conserving regulators are too quick to detect breaths, leading to 'double pulse' or 'multiple pulses' of oxygen delivery, especially in patients with long breathing patterns, and lack the sensitivity to accurately deliver oxygen during varying breathing conditions, unlike dual-lumen devices.
Innovation Solution
A pneumatic single-lumen medical gas conserver with a sensing valve, check valve, and control valve system that decouples the sensing valve from the patient port before oxygen delivery, implementing a pneumatically controlled delay to prevent double pulses and providing a user-selectable flow mode, including a constant flow option, to improve responsiveness and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-lumen conserver is used to simplify the device structure, then device complexity is reduced, but the sensitivity to detect breaths deteriorates, leading to double pulse deliveries
Solution Approach 1:
The patent divides the single sensing line into two functional segments: a sensing portion that detects breaths and a delivery portion that provides oxygen. The sensing valve and check valve create separate functional zones within the single-lumen structure, allowing the sensing mechanism to remain isolated from the delivery flow, thus maintaining sensitivity while simplifying the overall device structure.
Solution Approach 2:
The check valve acts as an intermediary element between the sensing valve and the delivery port. It allows the sensing valve to detect breaths by sensing pressure changes in the single-lumen cannula while preventing the delivery flow from interfering with the sensing mechanism. This intermediary component enables the single-lumen design to maintain breath detection sensitivity.
2Speed
If the sensing valve is directly coupled to the patient port, then response speed is improved, but double pulses occur in patients with long breathing patterns
Solution Approach 1:
The check valve performs a preliminary action by decoupling the sensing valve from the patient port before oxygen delivery begins. This preliminary decoupling prevents the sensing valve from being influenced by the delivery flow, ensuring that the sensing valve only detects breaths and does not trigger multiple pulses in patients with long breathing patterns.
Solution Approach 2:
The check valve serves as an intermediary that separates the sensing function from the delivery function in time and space. It allows the sensing valve to respond quickly to breaths while preventing direct coupling that would cause double pulses, thus maintaining both response speed and delivery accuracy.
3Reliability
If oxygen flow is delivered continuously through the hose, then delivery reliability is improved, but the device can no longer sense when inhalation ends
Solution Approach 1:
The patent segments the single-lumen cannula into a sensing portion and a delivery portion. The sensing valve is coupled to the sensing portion while the delivery valve controls flow to the delivery portion. This segmentation allows continuous delivery reliability while maintaining sensing accuracy by isolating the sensing mechanism from the delivery flow.
Solution Approach 2:
The check valve acts as an intermediary that maintains the separation between sensing and delivery functions. It ensures that oxygen flow through the delivery portion does not interfere with the sensing valve's ability to detect when inhalation ends, thus maintaining both delivery reliability and sensing accuracy.
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 conserver provides rapid response to inhalations without double pulses, maintaining sensitivity across different breathing patterns and allowing user-selectable flow rates, enhancing oxygen conservation and delivery precision.
Implementation Method 1
The sensing valve can be in gas communication with the patient port and can detect an inhalation by the patient so as to trigger delivery of the medical gas to the patient port
Implementation Method 2
The check valve can be gaseously disposed between the sensing valve and the patient port. The check valve can decouple the sensing valve from the patient port in response to detection of the inhalation by the sensing valve
Implementation Method 3
The delivery valve can be gaseously disposed between the supply port and the patient port for controlling the flow of medical gas to the patient port
Data Source
AI summary
A pneumatic single-lumen medical gas conserver combines the advantages of typical single-lumen and dual-lumen conservers. In particular, a pneumatic single-lumen conserver can provide a rapid response to patient inhalations without the need for a more expensive dual-lumen cannula hose. In addition, after delivering oxygen the conserver has a specific pneumatically-implemented delay period before being able to detect the next inhalation to inhibit “double pulse” deliveries. In addition to a conserving or pulse flow mode, the conserver can provide a user-selectable gas flow at a continuous or constant flow mode.