Bleed-Back Control Valve Sealing for Sliding Catheter Positioning
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Solution Overview
Problem
Existing bleed-back control valves, such as the Tuohy-Borst adapter, allow blood to backflow during catheter placement, increasing the risk of exposure to blood-borne pathogens and blood loss, as they require the catheter to be locked in place to prevent bleed-back, which limits their use.
Innovation Solution
A seal comprising conical gaskets with angularly offset registering structures and semi-conical flaps that dynamically and statically engage the catheter, allowing it to slide while preventing bleed-back through a combination of elastic spreading and frictional locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional Tuohy-Borst adapter is used to lock the catheter in place to stop backflow, then blood backflow is prevented, but the catheter cannot be positioned or adjusted
Solution Approach 1:
The sealing function is segmented into multiple independent conical gaskets with semi-conical flaps instead of a single locking mechanism. Each gasket can independently seal against the catheter, allowing the system to maintain sealing while the catheter moves through the segmented structure during positioning, then maintains seal when locked.
Solution Approach 2:
The conical gaskets with semi-conical flaps provide dynamic sealing capability that adapts to catheter movement. The flaps can move and deform to maintain contact with the catheter surface during insertion and positioning, then provide static sealing when the catheter is locked in place.
2Ease of operation
If the catheter is loosened to allow sliding for positioning, then catheter placement is enabled, but blood backflow occurs creating blood spill
Solution Approach 1:
The conical gaskets are pre-positioned and biased to engage the catheter surface before the catheter is fully inserted or locked. The registering structures align the gaskets in advance, ensuring sealing surfaces are ready to prevent backflow as soon as the catheter makes contact, even during the sliding insertion phase.
Solution Approach 2:
The conical gaskets are made of elastomeric material that can deform and conform to the catheter surface. This flexibility allows the gaskets to maintain sealing contact with the catheter during insertion and positioning movements, preventing blood spill while the catheter is being maneuvered.
3Device complexity
If a single gasket design is used, then the structure is simple, but sealing effectiveness during both insertion and locking is insufficient
Solution Approach 1:
The sealing system is divided into multiple conical gaskets (typically three) arranged around the catheter, each with semi-conical flaps. This segmentation provides redundant sealing paths and ensures that at least one gasket maintains effective contact with the catheter during both insertion and locked states, improving reliability without excessive complexity.
Solution Approach 2:
The conical gaskets are nested within each other in a concentric arrangement around the catheter. The semi-conical flaps of each gasket interlock with the registering structures of adjacent gaskets, creating a nested configuration that maximizes sealing effectiveness while maintaining a compact structure.
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 solution effectively prevents blood backflow during catheter insertion and positioning, reducing the risk of exposure and blood loss by allowing continuous catheter movement with simultaneous sealing, enhancing safety and efficiency.
Implementation Method 1
The conical gaskets and their semi-conical flaps are made of an elastomeric material that allows them to deform and conform to the catheter surface, providing both dynamic and static sealing.
Data Source
AI summary
A bleed-back control valve is provided having a sidearm and an integrated three-way stopcock switching between two alternative fluid paths. One of the alternative fluid paths communicates with an inline pressure transducer embedded in the wall of the sidearm. The bleed-back control valve also includes a purge valve located near the blunted apex of a conical seal located in the main valve body. The purge may be opened to expel air from the space around the blunted apex.