Blood Sampling Syringe With Self-Filling Filter and Volume Stops
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Solution Overview
Problem
Existing syringes require careful handling to obtain small volumes of blood accurately, particularly for blood gas tests, and lack ergonomic design and safety features for easy ventilation of the sample.
Innovation Solution
A syringe with a plunger and barrel configuration that includes first and second stops and a filter that changes permeability upon contact with blood, allowing self-filling and easy ventilation with a short push, ensuring the target volume is obtained without excess blood draw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional syringe is used to obtain small volumes of blood, then the blood sample can be obtained, but the user must handle the syringe very carefully and the process is not ergonomic
Solution Approach 1:
The syringe is pre-configured with a filter positioned at a predetermined location and stops defined in advance. The filter's predetermined position automatically defines the target blood volume when the plunger reaches the first stop, eliminating the need for careful manual measurement and handling during the procedure.
Solution Approach 2:
The filter automatically changes its gas- and liquid-permeability when it comes into contact with blood, self-regulating the blood inflow without user intervention. This self-service mechanism ensures the target volume is obtained accurately while simplifying user handling.
2Ease of operation
If the syringe is designed to obtain small target volumes of blood, then the blood draw is minimized, but the syringe lacks easy ventilation capability
Solution Approach 1:
The filter's gas- and liquid-permeability dynamically changes based on its state: it is permeable during the self-filling process to allow air evacuation, then becomes impermeable upon blood contact to preserve the blood sample. This dynamic property enables easy ventilation without compromising the small blood volume.
Solution Approach 2:
The filter's permeability parameters change automatically upon contact with blood, transitioning from a permeable state during filling to an impermeable state for sample preservation. This parameter change enables ventilation functionality while maintaining the integrity of the small blood volume target.
3Reliability
If the filter remains gas-permeable during blood draw, then air can be vented easily, but blood may leak through the filter after filling
Solution Approach 1:
The filter's gas- and liquid-permeability parameters automatically change upon contact with blood. During the self-filling process, the filter remains permeable to allow air to escape. Once blood contacts the filter, it becomes impermeable, preventing blood leakage while maintaining the reliability of the blood draw process.
Solution Approach 2:
The filter's contact with blood, which could be seen as a potential problem for leakage, is converted into a benefit by triggering the permeability change. This ensures blood leakage prevention while maintaining easy self-filling operation.
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 syringe facilitates accurate and ergonomic blood withdrawal with reduced patient stress, ensuring the target volume is obtained and safely vented, enhancing handling and transport safety.
Implementation Method 1
the filter is configured to be gas-permeable when the filter is not in contact with blood, and the filter is configured to become gas- and fluid-impermeable when getting in contact with blood
Implementation Method 2
the plunger is configured for guiding air out of the barrel and through the filter towards outside the syringe during a self-filling process of the syringe
Data Source
AI summary
A syringe for obtaining a target volume of blood is presented. The syringe (1) comprises a barrel (2), wherein a plunger (4) is arranged within the barrel (2) to be displaceable along a displacement direction (X). Furthermore the barrel (2) and the plunger (4) together provide for a first stop (20) and second stop (22), wherein the first stop (20) is configured for positioning a filter (100) at a predetermined location along the displacement direction (X) thereby defining a target volume of blood and a buffer volume. Moreover, the second stop (22) is configured to stop the plunger (4) from expelling more than the buffer volume from the syringe (1) for obtaining the target volume of blood when the plunger (4) is pushed towards the distal end (30) of the syringe (1) along the displacement direction (X). In addition, the syringe (1) facilitates that the syringe (1) fills itself with the target volume of blood by a self-filling procedure using blood that is under pressure, like arterial blood, and using the filter (100) located in the plunger (4).