Disengageable Catheter Assembly With Controlled Pull Separation
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Solution Overview
Problem
Existing indwelling catheters, particularly nephrostomy catheters, are prone to accidental dislodgement due to their flexible anchoring mechanisms, leading to potential damage and complications such as urine leakage and renal failure, necessitating frequent hospital visits and resource-intensive reinsertion procedures.
Innovation Solution
A disengageable catheter assembly with an indwelling catheter and an external tube that frictionally engage through varying-diameter engagement surfaces, allowing separation at a threshold force below the level required to dislodge the catheter from the body, and can be manually reconnected without specialized tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a flexible anchoring mechanism (pigtail) is used to stabilize the catheter within the body cavity, then the catheter can be easily inserted and positioned, but the catheter becomes prone to accidental dislodgement when subjected to pulling forces
Solution Approach 1:
The catheter assembly is divided into two separable components: an indwelling catheter with anchoring mechanism and an external tube. The external tube can be detached from the indwelling catheter when subjected to pulling forces, preventing transmission of dislodgement forces to the anchoring mechanism while maintaining stable positioning of the indwelling portion.
Solution Approach 2:
The external tube acts as an intermediary element between the user and the indwelling catheter. It provides a frictional engagement interface that can be deliberately detached at controlled forces, serving as a buffer that prevents direct transmission of excessive pulling forces to the anchoring mechanism.
2Reliability
If a strong anchoring mechanism is used to prevent dislodgement, then catheter retention stability is improved, but the risk of severe damage to body organs and tissues increases when the catheter is pulled
Solution Approach 1:
By separating the external tube from the indwelling catheter at controlled forces, the system isolates the harmful pulling forces from the anchoring mechanism. The indwelling catheter remains in place with its anchoring mechanism intact, while the external tube detaches to prevent force transmission that would cause severe damage to kidneys and flank tissues.
3Reliability
If the external tube is permanently connected to the indwelling catheter, then fluid communication is maintained, but accidental dislodgement occurs more frequently due to lack of detachment capability
Solution Approach 1:
The connection between the external tube and indwelling catheter is designed to be dynamic rather than static. The frictional engagement allows the connection to naturally respond to applied forces by detaching when pulling forces exceed a threshold, while maintaining connected state during normal use to ensure continuous fluid communication.
4Reliability
If a detachable connection mechanism is added to allow controlled separation, then accidental dislodgement is prevented, but the device complexity increases
Solution Approach 1:
The complex detachment mechanism is extracted and replaced by a simple frictional engagement interface. The separation capability is achieved through the inherent friction between the external tube and indwelling catheter surfaces, eliminating the need for additional mechanical detachment components while maintaining controlled separation functionality.
Solution Approach 2:
The frictional engagement interface is self-regulating and automatically responds to applied forces. When pulling forces exceed the friction threshold, the external tube naturally detaches without requiring additional actuation mechanisms. The system self-regulates the separation based on the magnitude of applied forces, simplifying the overall device 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
Prevents accidental dislodgement by allowing separation at a controlled force, reducing the risk of organ damage and simplifying reconnection, thereby minimizing hospital visits and resource consumption.
Implementation Method 1
an external tube frictionally engageable with the indwelling catheter
Data Source
AI summary
The present disclosure relates to catheter assemblies designed to provide fluid communication between an organ in a patient's body and the external environment. Such a catheter assembly can include an indwelling catheter equipped with an anchoring mechanism at a distal portion thereof, configured to transition between a compacted configuration and an expanded configuration, and an external tube configured to frictionally engage with a proximal end portion of the indwelling catheter. The frictional force between corresponding engagement surfaces of the indwelling catheter and the external tube is configured to allow disengagement therebetween in response to a pull force equal to or greater than a threshold separating pull force, applied to the external tube, wherein the threshold separating pull force can be designed to be lower than the pull force required to cause dislodgment of the indwelling catheter from the patient's body.