Optical Waveguide Feeding Tube Position Sensor

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Solution Overview

Problem

Current methods for confirming the correct placement of feeding tube fluid output apertures in patients are either costly, invasive, wasteful, or prone to false readings due to contamination, particularly for critically ill patients who cannot safely undergo radiography or require repeated procedures.

Innovation Solution

A disposable feeding tube position confirmation device using optical waveguides with color-changing sensors that indicate correct placement by detecting environmental chemicals like CO2 or pH, eliminating the need for expensive equipment and power sources, and providing immediate, accurate feedback on tube positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If radiography is used to confirm tube placement, then placement accuracy is confirmed, but cost and patient exposure to x-ray increase

Engineering Contradiction:
Improvetube placement confirmation accuracyVSAvoidcost and complexity of equipment
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent employs a disposable pH indicator strip that is inexpensive and single-use, eliminating the need for expensive radiography equipment while providing reliable placement confirmation. The strip is discarded after one use, avoiding contamination risks and reducing the need for costly imaging equipment.

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

Solution Approach 2:

The patent replaces the mechanical/radiological system (x-ray imaging) with a chemical indicator system (pH-sensitive color change). This substitution eliminates the need for expensive radiography equipment, power sources, and specialized facilities while providing equivalent or superior placement verification through colorimetric detection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If pH indicator is withdrawn to determine positioning, then placement can be assessed, but contamination leads to false readings

Engineering Contradiction:
ImprovepH measurement accuracyVSAvoidreading accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The pH indicator strip is pre-positioned at the distal end of the feeding tube before insertion. This preliminary placement ensures the indicator remains in the correct position within the patient's body, allowing accurate local pH measurement without the need to withdraw or manipulate the indicator, thereby preventing contamination and false readings.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an optical waveguide as an intermediary that transmits light from a remote source to the pH indicator and carries the color change signal back to the operator. This allows the pH indicator to remain in situ without direct manipulation, eliminating contamination risks while maintaining measurement accuracy through optical signal transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If pH measuring device is used continuously, then monitoring is improved, but power supply and cost increase

Engineering Contradiction:
Improvecontinuous monitoring capabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The pH indicator strip is self-contained and requires no external power source. It autonomously changes color in response to pH variations at the tube tip, providing continuous monitoring capability through passive chemical response. The optical waveguide system also requires no power at the measurement site, as light can be introduced from external sources.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses an inexpensive disposable pH indicator strip that provides monitoring functionality without requiring expensive powered devices. The strip is replaced rather than recharged, eliminating the need for power supplies, batteries, or complex electronic monitoring systems while maintaining reliable detection capability.

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

4Measurement precision

If feeding tube is repositioned multiple times, then correct placement is achieved, but patient distress and time increase

Engineering Contradiction:
Improveplacement accuracyVSAvoidprocedure time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The pH indicator strip is pre-positioned at the distal end of the feeding tube before insertion. This allows immediate assessment of placement accuracy as soon as the tube is inserted, eliminating the need for repeated withdrawals, repositioning, and reassessments. The indicator provides real-time visual feedback that confirms correct placement in a single procedure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements immediate visual feedback through the color-changing pH indicator that is continuously visible at or near the tube tip. This real-time feedback allows the operator to confirm correct placement during the insertion procedure itself, eliminating the need for repeated attempts, patient repositioning, or delayed verification, thereby reducing procedure time and patient distress.

Inventive Principle:
Principle #23Feedback

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 ensures accurate and cost-effective confirmation of feeding tube placement without the need for radiography or power, reducing complications and wastage, while being easy to use and minimizing distress to patients.

Implementation Method 1

the position confirmation device comprises an input optical waveguide and an output optical waveguide

Methodology Applied
Scientific EffectOptical waveguide: Waveguide (optics)

Implementation Method 2

the sensor means comprising a colour change indicator operable to change colour relative to the chemical content of the environment proximate thereto

Methodology Applied
Scientific EffectColor change indicator: Thermochromism

Implementation Method 3

detecting environmental chemicals like CO2 or pH

Methodology Applied
Scientific EffectpH detection:

Implementation Method 4

detecting environmental chemicals like CO2 or pH

Methodology Applied
Scientific EffectCO2 detection:

Data Source

PatentEP2412311B1Feeding tube position confirmation device
Publication Date: 2014.12.03 THOMAS SEAN JULIAN
  • EP2412311B1 patent drawingFigure 1~3
  • EP2412311B1 patent drawingFigure 4~6
  • EP2412311B1 patent drawingFigure 7~8

AI summary

A feeding tube position confirmation device having an input optical waveguide and an output optical waveguide dimensioned to be insertable into the lumen of a feeding tube. A sensor is disposed on the optical waveguides at a position thereon which corresponds to the predetermined portion of the feeding tube. The sensor means has a colour change indicator operable to change colour relative to the chemical content of the environment proximate thereto. The input optical waveguide is operable to carry light to the sensor means and the colour change indicator is operable to change to a predetermined colour upon detection of a predetermined chemical content The sensor means causes a change in the colour of the input light to provide an output light of a predetermined colour indicative of the position of the said feeding tube. The output light is carried to the proximate end of the position confirmation device, by the output optical waveguide, at which it is viewed by the user to determine the position of the said tube in the human or animal body.