Catheter Obstruction Detection via Electrochemical Impedance
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Solution Overview
Problem
Current sensors for detecting catheter obstructions in hydrocephalus shunts often rely on indirect measurements of flow or pressure, which can lead to inefficiencies and false positives or negatives, failing to provide direct and quantitative assessment of catheter patency over time.
Innovation Solution
A self-monitoring catheter system utilizing electrochemical impedance measurement between electrodes placed within and outside the catheter lumen, applying an AC signal to detect changes in impedance that indicate obstruction, allowing for real-time, quantitative assessment of catheter blockage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If indirect flow or pressure measurements are used to detect catheter obstruction, then the measurement system can be simpler, but the detection accuracy and reliability deteriorate due to false positives or negatives
Solution Approach 1:
The patent replaces indirect mechanical pressure or flow measurements with direct electrical impedance measurements. By injecting an electrical signal through the catheter lumen and measuring impedance changes, the system directly detects obstruction without relying on indirect pressure differentials or flow rate calculations, thereby improving detection accuracy while maintaining system simplicity
Solution Approach 2:
The patent introduces an electrical signal as an intermediary to detect catheter patency. Instead of directly measuring physical obstruction, the system uses electrical impedance as a mediator that changes in response to lumen blockage, providing accurate obstruction detection through a non-mechanical measurement approach
2Ease of manufacture
If indirect pressure or flow patterns are monitored to infer obstruction, then the measurement approach is simpler to implement, but the reliability of obstruction detection worsens due to inability to provide direct patency assessment
Solution Approach 1:
The patent replaces complex pressure differential sensors or flow meters with simple electrical impedance measurement circuitry. The impedance measurement system is easier to manufacture and implement while providing direct and reliable obstruction detection, as electrical measurements can be made with simple voltage and current sources combined with impedance analysis circuitry
3Speed
If snapshot measurements at single time points are used, then the measurement process is faster and simpler, but the ability to monitor progressive obstruction deteriorates
Solution Approach 1:
The patent implements continuous or repeated impedance measurements over time, creating a temporal profile of catheter patency. By continuously monitoring impedance changes, the system can detect progressive obstruction developments while maintaining fast measurement capability, as each individual impedance measurement remains quick while the series of measurements provides progressive monitoring
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
Enables accurate and timely detection of progressive or complete blockages in catheters, independent of patient orientation, providing reliable monitoring of catheter patency and obstruction, thereby improving shunt performance and patient outcomes.
Implementation Method 1
an impedance measurement instrument that measures changes in the impedance between the first and the second electrodes after the first electrode is exposed to fluid within the catheter lumen
Data Source
AI summary
A self-monitoring catheter system may detect an obstruction during use of a catheter. The system may include a catheter with an interior lumen that has one or more ports into the lumen; a first and a second electrode; and an impedance measurement instrument that measures changes in the impedance between the first and the second electrodes after the first electrode is exposed to fluid within the catheter lumen, thereby signaling an obstruction during use of the catheter.