Endotracheal Catheter Adsorption Reduction

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Solution Overview

Problem

Standard endo-tracheal catheters made from PVC materials exhibit substantial adsorption of anesthetic agents like Propofol, leading to inaccurate concentration measurements due to adsorption effects, which can delay and reduce signal strength in exhaled air monitoring during anesthesia procedures.

Innovation Solution

Incorporating an insert tube or coating with reduced adsorption characteristics, such as PTFE, PFA, FEP, or PEEK, within the catheter tube to prevent direct contact between the gaseous flow and the PVC tubular wall, allowing for accurate substance concentration measurement by minimizing adsorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a PVC catheter tube is used for cost-effective production, then manufacturing cost is reduced, but adsorption of anesthetic agents increases causing measurement inaccuracy

Engineering Contradiction:
Improvemanufacturing costVSAvoidsubstance concentration measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The catheter system is divided into two functional segments: the outer catheter tube (made from cost-effective PVC) and the inner insert tube (made from low-adsorption material). This segmentation allows each component to fulfill its specific function - the outer tube provides structural integrity and cost efficiency, while the inner tube ensures accurate substance concentration measurement by preventing adsorption of anesthetic agents.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insert tube acts as an intermediary element between the gaseous flow containing anesthetic agents and the PVC catheter tube wall. It mediates the interaction by providing a surface that does not adsorb anesthetic agents, thereby preventing the harmful adsorption effect while allowing the PVC outer tube to maintain its cost-effective manufacturing advantage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If PVC material is used for the catheter tube, then production cost decreases, but adsorption effects delay and reduce signal strength

Engineering Contradiction:
Improveproduction costVSAvoidsignal delay
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The catheter is segmented into an outer PVC tube for cost-effective production and an inner insert tube made from low-adsorption material. This segmentation eliminates the time delay caused by adsorption while maintaining the cost advantage of PVC manufacturing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insert tube serves as an intermediary that prevents direct contact between anesthetic agents and the PVC wall, thereby eliminating adsorption-induced signal delay and strength reduction while allowing the PVC outer tube to maintain cost efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If PVC material is used for the catheter tube, then manufacturing cost is reduced, but adsorption reduces signal strength

Engineering Contradiction:
Improvemanufacturing costVSAvoidmeasurement reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The catheter system is segmented into an outer PVC tube for cost-effective manufacturing and an inner insert tube for reliable measurement. This segmentation ensures that the measurement reliability is not compromised by adsorption effects while maintaining the cost advantage of PVC material.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insert tube acts as an intermediary barrier that prevents adsorption of anesthetic agents on the PVC wall, thereby ensuring reliable and accurate concentration measurements while allowing the PVC outer tube to provide cost-effective manufacturing.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If an insert tube with reduced adsorption characteristics is added, then measurement accuracy improves, but device complexity increases

Engineering Contradiction:
Improvesubstance concentration measurement accuracyVSAvoidcatheter structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The insert tube is nested within the outer catheter tube, with the inner tube placed inside the lumen of the outer tube. This nested configuration allows the low-adsorption insert tube to be integrated into the existing catheter structure without requiring complete redesign, thereby improving measurement accuracy while minimizing the increase in device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The catheter is segmented into an outer tube and an inner insert tube, where each segment has a specific function. This segmentation allows the system to achieve improved measurement accuracy through the insert tube while maintaining a relatively simple overall structure that can be manufactured cost-effectively.

Inventive Principle:
Principle #1Segmentation

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 use of insert tubes or coatings with reduced adsorption characteristics prevents the adsorption of anesthetic agents on the catheter wall, ensuring precise and accurate concentration measurements of anesthetic agents in exhaled air, thereby improving the reliability of anesthesia monitoring.

Implementation Method 1

a catheter tube made from a PVC material may exhibit a substantial adhesion for anesthetic agents, in particular Propofol, causing molecules to be adsorbed on the PVC tube wall

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP3684452B1Endo-tracheal catheter for use in an anesthetic procedure
Publication Date: 2024.07.31 FRESENIUS KABI DEUTSCHLAND GMBH
  • EP3684452B1 patent drawingFigure 1
  • EP3684452B1 patent drawingFigure 2~3

AI summary

An endo-tracheal catheter (1) for use in an anesthetic procedure comprises a catheter tube (10) to be inserted into the trachea (40) of a patient (4), the catheter tube (10) having a tubular wall (101) defining an inner lumen (102) for guiding a gaseous flow, and a connection piece (11) which defines a chamber (110) being in fluid connection with the catheter tube (10) and comprising a port (110) for connecting a detection device (2) to the endo-tracheal catheter (1) for detecting at least one substance in the gaseous flow flowing through the catheter tube (10). Herein, an insert tube (13) is received in the inner lumen (102) of the catheter tube (10) for guiding the gaseous flow through the catheter tube (10) and/or a coating (103) covers the tubular wall (101) at a side facing the inner lumen (102) for guiding the gaseous flow through the catheter tube (10). In this way, an endo-tracheal catheter is provided which allows for an accurate measurement of a substance concentration in a gaseous flow, in particular in the context of an anesthesia procedure.