Blood Collection Device Venting Mechanism
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Solution Overview
Problem
Existing blood collection devices face challenges in confirming accurate placement of the cannula tip in blood vessels due to air backpressure impeding blood flow, leading to delayed or missed venipuncture and potential harm to patients.
Innovation Solution
A blood collection device with a venting mechanism featuring a tubular insert and a membrane permeable to air but impermeable to blood, allowing rapid flashback detection and ensuring correct cannula placement, combined with a simple and cost-effective design for manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a closed cannula hub is used to collect blood, then blood can be collected effectively, but air backpressure impedes blood flow and delays flashback detection
Solution Approach 1:
The cannula hub is segmented into a closed chamber for blood collection and a separate venting mechanism with a membrane. This segmentation allows the main chamber to remain closed for effective blood collection while the membrane portion provides selective venting to reduce air backpressure and enable timely flashback detection.
Solution Approach 2:
The venting mechanism incorporates a membrane with localized selective permeability properties - permeable to air but impermeable to blood. This local quality difference allows the membrane to selectively allow air escape while blocking blood, resolving the contradiction between maintaining closed system integrity and reducing air backpressure for timely flashback detection.
2Loss of time
If a venting mechanism is added to reduce air backpressure, then flashback detection improves, but device complexity increases
Solution Approach 1:
The venting function is extracted as a separate, modular mechanism from the main cannula hub structure. This extracted venting mechanism can be independently designed and manufactured with simple components (membrane and housing), reducing the complexity burden on the main blood collection device while still achieving rapid flashback detection.
Solution Approach 2:
The venting mechanism utilizes a thin membrane film as its core component. This flexible film provides the necessary selective permeability function with minimal structural complexity, allowing air to pass through while blocking blood, thereby achieving improved flashback detection without significantly increasing device complexity.
3Productivity
If a membrane permeable to air but impermeable to blood is used, then flashback occurs rapidly, but manufacturing precision requirements increase
Solution Approach 1:
The membrane is constructed from porous material with controlled pore sizes that allow air molecules to pass through while blocking larger blood molecules and cells. This porous structure achieves the desired selective permeability through material science rather than complex manufacturing processes, maintaining manufacturing feasibility while enabling rapid flashback detection and efficient blood collection.
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
Enables quick and reliable venipuncture detection, ensuring gentle and efficient blood collection with reduced risk of patient harm and easy assembly.
Implementation Method 1
a membrane extending across the fluid passage, wherein the membrane is made from a material permeable for air and substantially impermeable for blood
Data Source
Figure 1~2
Figure 3
AI summary
The application relates to a blood collection device comprising: a cannula hub (10) defining a chamber (28); an inlet cannula (12) defining an axis and having a distal end and a lumen extending therethrough, the inlet cannula being mounted to the cannula hub such that the distal end of the inlet cannula is external of the cannula hub and such that the lumen through the inlet cannula communicates with the chamber; an outlet cannula (14) having a proximal end and a lumen extending therethorugh, the outlet cannula being mounted to the cannula hub such that the proximal end of the outlet cannula is external of the cannula hub and such that the lumen of the outlet cannula communicates with the chamber; a closed sleeve (34) mounted over a portion of the cannula disposed externally of the cannula hub; and a venting mechanism (38) providing communication between the chamber and ambient surroundings.