Catheter Distal End Flexibility and Temperature Adaptation
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Solution Overview
Problem
Conventional catheter assemblies often fail to insert the catheter into a blood vessel due to the catheter distal end being caught by the blood vessel wall, especially at large puncture angles, which can cause damage to the vessel wall.
Innovation Solution
A catheter assembly with a flexible portion at the distal end, made of a material with a smaller change in flexibility between 25°C and 37°C compared to the catheter body, preventing the catheter from being caught by the blood vessel wall and allowing easier insertion while minimizing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the catheter body is made hard for easy insertion, then the ease of operation is improved, but the catheter distal end may be caught by the blood vessel back wall causing damage
Solution Approach 1:
The catheter is designed with different flexibility characteristics at different locations: the catheter body is made relatively hard for easy insertion and manipulation, while the distal end is made flexible to prevent catching on the blood vessel back wall. This spatial differentiation of mechanical properties resolves the contradiction between ease of insertion and prevention of vessel damage.
Solution Approach 2:
The catheter's flexibility is made temperature-dependent, allowing it to dynamically change its mechanical properties. At room temperature (25°C), the catheter maintains higher flexibility for safe insertion, while at body temperature (37°C), it becomes harder and more rigid for stable indwelling and resistance to crushing during blood suction.
2Object-affected harmful factors
If the distal end of the catheter is made soft to prevent damage to the blood vessel, then the harmful factors are reduced, but the catheter may be crushed during blood suction
Solution Approach 1:
The catheter material's mechanical properties are changed as a function of temperature. The catheter is made of a material that exhibits lower flexibility (higher rigidity) at body temperature (37°C) compared to room temperature (25°C). This parameter change allows the distal end to be soft during insertion to prevent vessel damage, yet strong during blood suction to resist crushing forces.
3Reliability
If the catheter body is made hard for stable indwelling, then the reliability is improved, but the stimulation to the blood vessel increases causing phlebitis and extravasation
Solution Approach 1:
The catheter dynamically adapts its mechanical properties to the operational phase: during insertion, it remains flexible to minimize trauma; during indwelling, it becomes harder at body temperature to provide stability and resistance to crushing, while still adapting to the vessel shape to reduce stimulation and prevent complications like phlebitis and extravasation.
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 flexible portion allows for successful insertion without damaging the blood vessel, and after indwelling, the catheter body softens to adapt to the vessel shape, reducing stimulation and risk of complications like phlebitis and extravasation.
Implementation Method 1
A change in flexibility of the second material between 25° C. and 37° C. is smaller than a change in flexibility of the first material between 25° C. and 37° C.
Implementation Method 2
after the catheter is indwelled, the catheter body softens due to the body temperature as compared with the time of insertion and adapts to a shape of the blood vessel
Data Source
AI summary
A catheter assembly includes a catheter and an inner needle. The catheter has a catheter body and a flexible portion that is provided on a distal portion of the catheter body, includes a distal-most portion of the catheter, and is more flexible than the catheter body. The catheter body is made of a first material. The flexible portion is made of a second material. A change in flexibility of the second material between 25° C. and 37° C. is smaller than a change in flexibility of the first material between 25° C. and 37° C.