Catheter Positioning With Nerve Stimulator Needle and Clamp
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Solution Overview
Problem
Current regional anesthesia techniques face challenges in accurately placing catheters for continuous infusion due to issues with needle size, catheter flexibility, and fluid leakage, leading to suboptimal nerve blockades and increased patient discomfort.
Innovation Solution
A system featuring a thin catheter with a 27-gauge nerve stimulator needle and a releasable clamp to maintain precise positioning of the catheter and needle tip near the target nerve, reducing trauma and leakage by allowing controlled advancement and withdrawal of the catheter needle assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a large introducing needle (17 or 18 gauge) is used to allow passage of a smaller catheter, then the catheter can be placed, but patient trauma and discomfort increase
Solution Approach 1:
The catheter is threaded through the internal lumen of the needle, with the needle serving as an introducing element. The needle hub contains a hub bore through which the catheter passes, allowing the catheter to be delivered through a smaller gauge needle (20 or 22 gauge) rather than requiring a large 17 or 18 gauge needle, thereby reducing patient trauma while maintaining placement capability
Solution Approach 2:
The needle is first advanced to the target location and positioned near the nerve before the catheter is threaded through the needle lumen. This preliminary positioning of the needle eliminates the need for a large introducing needle, as the catheter is delivered through the already-positioned smaller needle, reducing trauma while ensuring accurate final catheter placement
2Object-affected harmful factors
If the catheter is made flexible to reduce trauma, then patient comfort improves, but accurate positioning of the distal end becomes difficult
Solution Approach 1:
A nerve stimulator is used to provide feedback on catheter positioning. Electrical stimulation through the catheter confirms proximity to the target nerve, allowing accurate positioning to be achieved despite catheter flexibility. The stimulator response serves as real-time feedback to guide and verify catheter placement
3Object-affected harmful factors
If the catheter diameter is smaller than the needle diameter, then trauma is reduced, but fluid leakage occurs at the skin entry point
Solution Approach 1:
The needle is withdrawn from the catheter after the catheter has been positioned near the target nerve. The catheter remains in place for continuous infusion while the introducing needle is removed. This extraction of the needle eliminates the source of leakage (the larger needle diameter at the skin entry) while maintaining the benefit of reduced trauma from using a smaller gauge needle for initial access
4Measurement precision
If a stiff catheter is used to maintain positioning control, then positioning accuracy improves, but nerve trauma increases
Solution Approach 1:
The catheter transitions from a flexible state during insertion and positioning to a more stable state during continuous infusion. The catheter's flexibility allows it to be advanced through tissue without causing trauma, while its position is maintained through the stability provided by the hub and hub bore structure, and verified through nerve stimulator feedback
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
This system simplifies and enhances the accuracy of neural blockade anesthesia administration, reduces patient trauma, and minimizes fluid leakage, facilitating efficient and cost-effective continuous regional anesthesia.
Implementation Method 1
Such method was premised upon the phenomenon that an electrical pulse is capable of stimulating a motor nerve fiber to contract an innervated muscle or cause paraesthesia, in the case of sensory nerve stimulation.
Data Source
AI summary
A system for positioning a catheter includes a nerve stimulator needle carried within the lumen of the catheter. A microelectrode is configured as a needle tip precisely protruding beyond a tapered distal end of the catheter. The catheter and needle are fixed against axial movement relative to one another to maintain the precise configuration of the microelectrode needle tip conductive surface by a releasable clamp which is grasped by the practitioner to compress the catheter lumen against the needle without permanent deformation of the needle shaft while simultaneously advancing the needle and the catheter toward a target nerve.