Multi-Sensor Infusion System Air Occlusion Detection

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Solution Overview

Problem

Existing infusion systems rely on single-sensor based methods for detecting air and occlusions in fluid delivery lines, which lead to false positives and negatives due to faulty sensor readings and variable pressure conditions, resulting in unnecessary interruptions of therapy.

Innovation Solution

A multi-sensor system that integrates signals from air, force, and pressure sensors to improve the robustness and reliability of air and occlusion detection, using algorithms to combine and qualify these signals for accurate determination of air presence and occlusions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If single-sensor based methods are used for air detection, then device complexity is reduced, but measurement precision and reliability deteriorate due to false positives and negatives

Engineering Contradiction:
Improvesensor system complexityVSAvoidair detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent combines multiple different types of sensors (acoustic air sensor, force sensor, pressure sensor) to detect air in the fluid delivery line. By merging the detection capabilities of these different sensor types, the system achieves higher measurement precision and reliability compared to single-sensor systems, while the complexity increase is managed through integrated processing algorithms.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple different types of sensors are integrated, then measurement precision and reliability of air detection are improved, but device complexity increases

Engineering Contradiction:
Improveair detection reliabilityVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system merges multiple sensor types (acoustic, force, pressure) to improve reliability of air detection. The different sensors complement each other to reduce false positives and negatives, with the acoustic sensor detecting air bubbles, the force sensor detecting changes in fluid resistance, and the pressure sensor monitoring pressure variations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediary processing system that receives signals from multiple sensors and applies algorithms to qualify and combine these signals. This intermediary processing layer manages the complexity by systematically integrating the sensor data rather than requiring direct complex interconnections between all sensor components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If single-sensor based algorithms are used, then device complexity is minimized, but false positive detection occurs due to faulty sensor readings from variable pressure conditions

Engineering Contradiction:
Improvedetection algorithm complexityVSAvoidocclusion detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces an intermediary qualification process that receives raw sensor signals and applies algorithms to determine whether detected conditions represent true air presence or occlusion. This intermediary processing layer qualifies the sensor readings by comparing multiple sensor outputs and applying decision logic, thereby reducing false positives while managing algorithmic complexity in a structured manner.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 multi-sensor system reduces false positive air detection, enhances sensitivity and specificity of air detection, and improves occlusion detection accuracy, minimizing unnecessary interruptions in fluid delivery.

Implementation Method 1

When fluid is present in the tube, propagation of the acoustic signal is efficient and produces a large electrical signal via the receiver circuit. On the other hand, the presence of air in the tube causes an acoustical open circuit which substantially attenuates the detected signal.

Methodology Applied
Scientific EffectAcoustic signal propagation and attenuation: Acoustics

Implementation Method 2

The measured force during a pumping cycle is directly related to the type of fluid in the chamber. For instance, fluids are relatively incompressible and generate a higher and different force profile than air.

Methodology Applied
Scientific EffectFluid compressibility and force generation:

Implementation Method 3

Similarly, a combination of fluid and air in the chamber results in a hybrid force profile that is indicative of the mixture percentages.

Methodology Applied
Scientific EffectPressure measurement:

Data Source

PatentEP3003429B1Multi-sensor infusion system for detecting air or an occlusion in the infusion system
Publication Date: 2020.02.26 ICU MEDICAL INC
  • EP3003429B1 patent drawingFigure 1
  • EP3003429B1 patent drawingFigure 2~4
  • EP3003429B1 patent drawingFigure 5

AI summary

An infusion system for being operatively connected to a fluid delivery line and to an infusion container includes a pump, a plurality of different types of sensors connected to the pump or the fluid delivery line, at least one processor, and a memory. The plurality of different types of sensors are configured to indicate whether air is in the fluid delivery line. The memory includes programming code for execution by the at least one processor. The programming code is configured to, based on measurements taken by the plurality of different types of sensors, determine: whether there is air in the fluid delivery line; whether there is a partial occlusion or a total occlusion in the fluid delivery line; or a percentage of the air present in the fluid delivery line or the probability of the air being in the fluid delivery line.