Cap Assembly for Lock Solution Syringe
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Solution Overview
Problem
Existing lock solution delivery devices for indwelling catheter assemblies often fail to effectively prevent retrograde blood flow and bacterial contamination, as they are unable to displace sufficient fluid to flush out blood and are susceptible to bacterial contamination due to their reusable nature and limited fluid displacement capabilities.
Innovation Solution
A cap assembly with a housing and plunger system that includes a biasing member and a fluid channel, allowing for the displacement of a larger volume of fluid (1-2 mL) and preventing blood from entering the catheter assembly upon syringe removal, featuring a resilient valve to seal during transport and a sealing rib for secure engagement, ensuring effective flushing and locking without drawing blood back into the catheter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a reusable valve/connector is used to deliver medication through the catheter assembly, then the device can be used multiple times, but it is susceptible to bacterial contamination and cannot effectively prevent retrograde blood flow
Solution Approach 1:
The patent employs a disposable cap assembly that is discarded after a single use, eliminating the risk of bacterial contamination associated with reusable devices. The cap assembly includes a plunger that forces lock solution through the catheter and a valve mechanism that prevents blood from entering the catheter when the syringe is removed, providing reliable single-use functionality without contamination risk.
2Device complexity
If a traditional valve/connector is used, then the device structure is simple, but it cannot displace sufficient fluid to flush out blood effectively
Solution Approach 1:
The cap assembly incorporates a dynamic plunger mechanism that can be manually advanced to force a large volume of lock solution (1-2 mL or more) through the catheter assembly. The plunger is guided by a track system that ensures proper alignment and forces the solution through the catheter to flush out blood, providing effective fluid displacement while maintaining relatively simple device structure.
3Ease of operation
If the syringe is removed from the valve/connector, then the medication delivery is complete, but a vacuum is drawn creating retrograde blood flow into the catheter assembly
Solution Approach 1:
The cap assembly includes a valve mechanism that is activated when the syringe is removed from the inlet connector. This valve automatically closes to prevent vacuum formation and retrograde blood flow into the catheter assembly. The valve is spring-loaded or mechanically biased to remain closed during syringe removal, providing preliminary protection against blood flow reversal before it can occur.
Solution Approach 2:
The cap assembly acts as an intermediary device between the syringe and the catheter assembly. It includes a plunger that forces lock solution through the catheter and a valve that mediates the connection between the syringe and catheter, preventing direct vacuum formation in the catheter when the syringe is removed. This intermediary mechanism effectively blocks the pathway for retrograde blood flow.
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 cap assembly effectively prevents retrograde blood flow and reduces the risk of bacterial contamination by ensuring complete fluid displacement and secure sealing, thereby minimizing the risk of clotting and bio-film formation, enhancing catheter assembly hygiene and functionality.
Implementation Method 1
The biasing member may include a coil spring
Implementation Method 2
The distal end of the plunger may have a cylindrical portion which is movably received within a cylindrical portion of the receptacle. The cylindrical portion of the plunger includes at least one annular sealing rib positioned to slidable and sealingly engage an inner wall of the cylindrical portion of the receptacle.
Data Source
AI summary
A cap assembly is disclosed for use with a lock solution delivery device. The cap assembly includes a housing defining a receptacle and having an inlet end and an outlet end. A plunger is movable axially within the receptacle from a retracted position to an advanced position and is rotatably supported within the receptacle from a first position to a second position. The plunger includes an axial extension configured to non-rotatably engage a syringe connected to the inlet end of the housing. The plunger is positioned to move from the first position to the second position in response to rotatable detachment of a syringe from the inlet end of the housing.