Disposable Moisture Detection Cuff for Dialysis Tubing

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Solution Overview

Problem

Existing devices for monitoring vascular access in extracorporeal blood treatments, such as dialysis, face challenges in being cost-effective, easy to handle, and providing wearer comfort, especially with the Luer-Lock connection system which can become loose or develop micro-cracks, and existing moisture detection devices are expensive and difficult to handle.

Innovation Solution

A moisture detection device with an electrically conductive structure designed as a deformable cuff that can be quickly and securely fastened around hose lines or connection systems, featuring a liquid-impermeable outer layer and absorbent inner layer to prevent false alarms, and using connection contacts that are spatially separated from the moisture sensor for easy handling and sterilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a housing with moisture sensor is used, then moisture detection is achieved, but production cost increases and handling becomes difficult

Engineering Contradiction:
Improvemoisture detection capabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent implements a disposable moisture detection element that is integrated into the connection system, eliminating the need for expensive reusable housings. The detection element is designed to be discarded after single use, significantly reducing production costs while maintaining reliable moisture detection functionality throughout the intended service period.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The moisture sensor is merged directly with the connection elements (Luer lock components), eliminating the separate housing structure. This integration reduces manufacturing steps, lowers production costs, and simplifies the overall device architecture while preserving the moisture detection capability.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a housing with moisture sensor is used, then moisture detection is achieved, but handling becomes difficult

Engineering Contradiction:
Improvemoisture detection capabilityVSAvoidhandling ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

By merging the moisture sensor with the connection elements themselves, the device becomes more compact and easier to handle. The integrated design eliminates bulky housings and complex assembly requirements, making the device more maneuverable during medical procedures while maintaining detection reliability.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If absorbent material is placed on patient skin, then moisture detection is achieved, but false alarms increase due to perspiration

Engineering Contradiction:
Improvemoisture detection capabilityVSAvoidfalse alarms from perspiration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a selective permeable barrier or hydrophobic coating as an intermediary layer between the patient's skin and the moisture sensor. This layer allows blood moisture to reach the sensor while blocking perspiration, thereby eliminating false alarms caused by normal body sweat while maintaining detection of dangerous blood leaks.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The detection system is designed to detect moisture only at specific localized areas where blood leakage would occur (connection points), rather than monitoring the entire skin surface. This localized approach distinguishes between perspiration (distributed) and blood leakage (localized at connection points), reducing false alarms.

Inventive Principle:
Principle #3Local quality

4Reliability

If Luer-Lock connection system is used, then connection security is improved, but loosening and micro-cracks occur due to improper handling

Engineering Contradiction:
Improveconnection securityVSAvoidloosening and micro-cracks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The moisture detection element is pre-installed and integrated into the Luer-Lock connection system before use. This preliminary integration ensures that the detection function is already in place and protected, preventing damage during assembly while maintaining the high security of the Luer-Lock connection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The connection system with integrated moisture detection is designed as a disposable unit that is discarded after single use. This eliminates the accumulation of wear, loosening, and micro-cracks that occur with repeated use of reusable connections, maintaining connection security and detection reliability throughout the device's service life.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 device allows for reliable detection of moisture leaks, including slow blood loss, without the need for additional securing mechanisms, is easy to attach and detach, and can be manufactured inexpensively in large quantities, enhancing wearer comfort and reducing the risk of false alarms.

Implementation Method 1

a moisture sensor which is designed as an electrically conductive structure

Methodology Applied
Scientific EffectElectrical conductivity: Conduction (electrical)

Implementation Method 2

an inner, liquid-absorbent layer facing away from the patient

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3192482B1Device for detection of moisture for a device for monitoring access to a patient
Publication Date: 2019.12.18 FRESENIUS MEDICAL CARE DEUTSCHLAND GMBH
  • EP3192482B1 patent drawingFigure 1
  • EP3192482B1 patent drawingFigure 2~3
  • EP3192482B1 patent drawingFigure 4~8

AI summary

The invention relates to a device 20 for detecting moisture for a device B for monitoring access to a patient for a facility A, with which a fluid is supplied to a patient and/or a fluid is drained from the patient via a tubing line, in particular for monitoring vascular access during extracorporeal blood treatment, especially for monitoring a central venous catheter 5 for acute dialysis. The moisture detection device according to the invention is characterized in that at least one section of the moisture detection device 20 is designed as a section 30A that can be deformed into a cuff and placed around the circumference of the tubing line or a connection system of the tubing line.The cuff-shaped section 30A has fastening means 37, 48 for fixing the cuff-shaped section in the position enclosing the hose or connection system. The cuff-shaped section allows the moisture detection device to be attached quickly and securely to a hose or connection system.