Holographic Occlusion Detection for Infusion Pumps

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Solution Overview

Problem

Current occlusion detection systems for infusion pumps suffer from poor signal-to-noise ratios and are prone to errors due to the optical properties of tubing, fluid, and ambient conditions, making it difficult to accurately detect pressure changes and occlusions in medical settings.

Innovation Solution

A holographic occlusion detection system using a white-light holographic label on a pressure sensor connected to infusion tubing, where pressure changes cause physical distortion of the label, shifting the peak wavelength of reflected light, which is then calibrated to determine pressure within the infusion line, and a unique optical signature distinguishes the sensor from others to prevent improper use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optical interferometry is used to detect pressure changes, then measurement precision is improved, but device complexity increases due to precise alignment requirements

Engineering Contradiction:
Improvepressure detection accuracyVSAvoidoptical component alignment
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the pressure sensing function from complex optical interferometry and implements it through a simplified holographic label system. The holographic label directly converts pressure changes into optical signal changes without requiring complex interferometric alignment, thus maintaining measurement precision while reducing device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical alignment system of optical interferometry with a holographic labeling system. Instead of requiring precise mechanical alignment of optical components, the system uses a holographic label that inherently encodes the pressure information in its optical structure, eliminating the need for complex mechanical alignment procedures.

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

2Reliability

If strain gauge is used to detect occlusion, then occlusion detection capability is provided, but signal-to-noise ratio deteriorates

Engineering Contradiction:
Improveocclusion detection capabilityVSAvoidsignal-to-noise ratio
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent utilizes optical signal changes in the holographic label, which can be detected as changes in light properties (analogous to color changes), to detect pressure variations. This optical detection method provides a higher signal-to-noise ratio compared to mechanical strain gauge measurements, as the holographic label's optical characteristics are more sensitive and less prone to noise interference.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The holographic label acts as an intermediary between the pressure changes in the infusion line and the detection system. It converts mechanical pressure changes into optical signal changes, providing a cleaner and more reliable signal that improves the signal-to-noise ratio while maintaining occlusion detection capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If optical pressure monitoring is used, then pressure detection is enabled, but measurement accuracy deteriorates due to tubing and fluid properties

Engineering Contradiction:
Improvepressure detection capabilityVSAvoidmeasurement accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies a holographic label specifically at the pressure sensing location within the infusion line. This localized application ensures that the optical measurement is taken directly at the point of interest,不受 the influence of tubing properties, fluid characteristics, or ambient conditions at other locations. The holographic label provides local, direct pressure measurement that maintains accuracy despite variations in tubing and fluid properties.

Inventive Principle:
Principle #3Local quality

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

This system provides faster and more accurate occlusion detection with reduced errors, ensuring precise pressure monitoring and preventing catastrophic delays in occlusion detection, while the unique optical signature helps in identifying the correct sensor for specific medical procedures.

Implementation Method 1

Pressure changes within the tubing result in a physical distortion of the white-light holographic label, thereby resulting in a shift in the peak wavelength of the reflective light sensed by the detector

Methodology Applied
Scientific EffectHolographic distortion:

Implementation Method 2

a light source configured to shine light onto the holographic label; and a photodetector oriented to detect the light reflected from the holographic label

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2332598B1Holographic occlusion detection system for infusion pumps
Publication Date: 2020.08.12 ROCHE DIABETES CARE GMBH
  • EP2332598B1 patent drawingFigure 1
  • EP2332598B1 patent drawingFigure 2
  • EP2332598B1 patent drawingFigure 3~5

AI summary

A holographic occlusion detection system has a white-light holographic label (204) placed onto a sensing portion or surface (206) of a pressure sensor (106) connected to infusion tubing (104, 108). The pressure sensor at the sensing portion can have a relatively thin wall section and may be wider and flatter than a normal cross section of the infusion tubing. The label is then illuminated by a polychromatic light source (214), and the light reflected off the holographic label is then received by a photodetector (216). Pressure changes within the tubing cause a change in orientation of the white-light holographic label, thereby resulting in a shift in the peak wavelength of the reflective light sensed by the photodetector. This shift in wavelength can then be calibrated to the swelling of the sensing portion so that pressure within the infusion line can be calculated. In another variation, monochromatic light is reflected off a holographic label, and pressure changes are detected by measuring the amplitude of the reflected light.