Pressure-Sensitive Conductive Composite Catheter Sensor
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Solution Overview
Problem
Conventional medical devices lack sufficient contact sensitivity, particularly in RF ablation treatments, due to the distance between electrode-tissue contact and force application, making it challenging to accurately assess tissue contact and control medical procedures effectively.
Innovation Solution
A catheter assembly incorporating a pressure-sensitive conductive composite (PSCC) member with varying electrical resistance based on applied pressure, coupled with measurement terminals and a reference electrode, allows for precise measurement of contact between the catheter and tissue, enabling improved contact sensitivity and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electrode-tissue contact is used in RF ablation, then the device can be kept simple, but contact sensitivity is insufficient due to the distance between electrode-tissue contact and force application
Solution Approach 1:
The catheter is divided into separate functional segments: a distal tip assembly with electrode for tissue contact and a proximal assembly with force application mechanism. The PSCC sensor is positioned in the tip assembly to detect contact forces directly at the tissue interface, separating the sensing function from the force application function to improve contact sensitivity.
Solution Approach 2:
A pressure-sensitive conductive composite (PSCC) sensor serves as an intermediary element between the electrode and the tissue. This sensor converts mechanical contact forces into electrical resistance changes, enabling indirect measurement of tissue contact with high sensitivity without requiring direct mechanical coupling.
2Measurement precision
If the electrode-tissue contact point is positioned 150 cm away from force application, then the catheter can be simpler in design, but accurate assessment of tissue contact becomes challenging
Solution Approach 1:
The sensing mechanism transitions from measuring forces at a distance (150 cm away) to measuring contact forces directly at the tissue interface by positioning the PSCC sensor in the distal tip assembly. This dimensional relocation of the sensor enables accurate contact assessment regardless of catheter length.
3Reliability
If conventional sensing devices are used, then manufacturing can be simpler, but contact sensitivity is insufficient for effective medical procedure control
Solution Approach 1:
The sensor utilizes a pressure-sensitive conductive composite material that combines conductive particles embedded in a polymer matrix. This composite material provides both mechanical compliance for tissue contact and electrical sensitivity for force detection, achieving high reliability without complex manufacturing by using a single material system.
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 PSCC-based sensor assembly enhances contact sensitivity, allowing for accurate assessment and control of tissue contact, reducing manufacturing complexity and increasing reliability while supporting a wide range of tissue environments.
Implementation Method 1
a pressure sensitive conductive composite member whose electrical resistance varies with pressure applied to the catheter assembly
Implementation Method 2
a quantum tunneling composite member having a first end and a second end, and being located between the catheter shaft and the catheter tip
Data Source
AI summary
A catheter assembly for assessing contact between the catheter assembly and tissue is disclosed. The assembly includes a catheter shaft and a pressure sensitive conductive composite member whose electrical resistance varies with pressure applied to the catheter assembly. The assembly also includes at least one measurement terminal to permit the measurement of changes in the electrical characteristics of the pressure sensitive conductive composite member. The assembly may optionally include a measurement device to measure resistance, impedance and/or other electrical characteristics. The assembly may utilize a reference electrode secured to the patient's tissue, which permits the measurement device to measure changes between the reference electrode and the at least one measurement terminal. Optionally, the assembly may include a conductive outer layer. Also disclosed are sensor assemblies, contact sensor, methods of contact sensing, and methods of manufacturing relating to the use of pressure sensitive conductive composites.