Ventilator Sampling Device Using One-Way Valve
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Solution Overview
Problem
Current methods for collecting Volatile Organic Compounds (VOCs) in exhaled breath from patients on ventilators are complex and often ineffective at detecting compounds at sub-PPB levels, particularly when using diffusive sampling tubes which have limited ranges of compounds they can collect.
Innovation Solution
The system utilizes the pressurization cycle of ventilators to actively flow exhaled air through an adsorbent, eliminating the need for additional pumps. This setup includes a sample collection device with multiple sorbent beds and a sleeve to increase the volume of air sampled, allowing for the detection of VOCs down to sub-PPB levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If diffusive sampling tubes are used to collect VOCs, then the sampling process is simple, but the range of compounds collected is limited and detection sensitivity is reduced
Solution Approach 1:
The sampling system is segmented into multiple functional components: a sampling pump for active flow control, multiple sorbent traps (including Tenax TA and Carbograph) for different compound ranges, and a GCMS analysis system. This segmentation allows each component to be optimized for its specific function, enabling broad compound coverage while maintaining operational simplicity through automated control.
Solution Approach 2:
The system uses multiple sorbent materials (Tenax TA for volatile compounds, Carbograph for semi-volatile compounds) that can collectively capture a wide range of VOCs from C2 to C12 hydrocarbons and various functional groups. This multi-functional approach allows a single sampling system to detect diverse compound classes that would require different specialized tubes otherwise.
2Loss of time
If vacuum canisters are used for sample collection, then multiple analyses can be performed, but the sampling process becomes more complicated with flow restrictors and controllers
Solution Approach 1:
The system uses a one-way valve that automatically directs airflow into the sampling trap during patient exhalation without requiring manual operation or complex control mechanisms. The ventilator's inherent pressure cycling provides the driving force for sampling, eliminating the need for external pumps or flow controllers, thereby simplifying the device while maintaining efficient sample collection.
Solution Approach 2:
The sampling system is integrated with the existing ventilator circuitry, merging the sampling function into the ventilator's existing airflow path. The one-way valve is inserted into the expiratory limb, and the sampling trap connects to the ventilator outlet, allowing sample collection to occur through the ventilator's normal operation without adding separate complex sampling infrastructure.
3Quantity of substance
If thermal desorption tubes are used, then the cost is reduced, but the sampling process becomes more complicated requiring pumps and power sources
Solution Approach 1:
The system leverages the ventilator's inherent pressure cycling during normal operation to provide the driving force for sample collection. The one-way valve automatically opens during exhalation when pressure increases, allowing breath samples to flow through the sorbent trap without requiring external pumps or power sources, thereby maintaining low cost while avoiding the complexity of additional mechanical components.
Solution Approach 2:
The one-way valve acts as an intermediary component that mediates between the ventilator's pressure cycling and the sample collection process. It translates the ventilator's natural pressure variations into controlled sampling flow, eliminating the need for complex pump systems while maintaining effective sample collection at low cost.
4Measurement precision
If canisters are used for breath sampling, then VOCs can be collected, but time-weighted average sampling over minutes or hours becomes complicated with flow restrictors
Solution Approach 1:
The system uses the ventilator's inherent pressure cycling during each breath cycle to automatically drive sample flow through the sorbent trap. The one-way valve opens and closes rhythmically with each exhalation, providing automatic flow control without external restrictors or controllers, enabling time-weighted average sampling through natural ventilator operation.
Solution Approach 2:
The sampling occurs periodically with each ventilator breath cycle, utilizing the rhythmic pressure changes during inspiration and exhalation. The one-way valve opens during exhalation phases and closes during inspiration, creating automatic periodic sampling that accumulates time-weighted average data over extended periods without requiring continuous flow 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 method enables the collection of a significant volume of air, allowing for the detection of VOCs at low concentrations, thereby improving the monitoring of disease indicators and anesthesia levels in breath samples.
Implementation Method 1
a tube is connected to the outlet line of the ventilator... the exhaled air can be sampled without the use of an additional pump... flow into the adsorbent
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A sample collection device collects Volatile Organic Compounds (VOCs) in exhaled breath in the outlet of a breathing assisted ventilator. The sample collection device is attached to the ventilator outlet line through a coupler containing either two check valves, or a check valve and a restrictive outlet flow path. During sampling, the exhaled air flows through a sorbent contained in the sample collection device as the ventilator pressure increases and decreases during the assisted breathing process. The flow of the exhaled air through the sample collection system is driven by the alternating pressure in the ventilator line without the need for an additional pump or power supply separate from the ventilator pump and power supply. The sample collection device can be used to monitor levels of bacteria-produced VOCs as an early detection of pneumonia and to allow feedback on the effectiveness of antibiotic treatment.