NPWT Blockage Detection via Pump Parameters

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current negative pressure wound therapy systems face challenges in accurately detecting blockages in suction tubes without generating false alarms, particularly distinguishing blockages from other zero-flow conditions, and require additional sensors or components.

Innovation Solution

The system employs methods involving generating negative pressure, recording pressure drops during ventilation, and using classification algorithms with support vector machines to differentiate between blocked and unblocked conditions based on recorded pressure data and pump turns, without the need for additional sensors like pressure sensors or flow meters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional sensors like pressure sensors or flow meters are used to detect blockages, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveblockage detection accuracyVSAvoidnumber of sensors and components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The existing pump serves dual functions: both maintaining negative pressure therapy and detecting blockages through its operational characteristics. The controller monitors pump current, voltage, and rotation speed to infer blockage conditions, eliminating the need for separate detection sensors. This self-service approach allows the pump to provide both therapeutic function and diagnostic capability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces mechanical sensing systems (pressure sensors, flow meters) with an electrical/electronic detection system that monitors the pump's electrical parameters (current, voltage, power consumption) and operational parameters (rotation speed). This substitution uses electrical measurements instead of mechanical sensing to detect blockages, reducing device complexity while maintaining detection capability.

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

2Reliability

If blockage detection methods are implemented to distinguish blockages from zero-flow conditions, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvefalse alarm reductionVSAvoidcontrol algorithm complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The controller continuously monitors pump operational parameters and compares them against expected ranges to detect blockage conditions. The system uses feedback from pump current, voltage, and rotation speed measurements to dynamically adjust therapy delivery and generate appropriate alerts. This feedback mechanism enables reliable distinction between true blockages and normal zero-flow conditions without requiring complex additional hardware.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent detects blockages by monitoring changes in pump operational parameters (current, voltage, power consumption, rotation speed) rather than directly measuring pressure or flow. By tracking parameter deviations from normal operating ranges, the system can reliably identify blockage conditions and distinguish them from other states using relatively simple control logic.

Inventive Principle:
Principle #35Parameter changes

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 approach allows for timely and reliable detection of blockages, reducing false alarms and enabling effective discrimination between blockage and zero-flow conditions, thus ensuring uninterrupted therapy and improved user safety.

Implementation Method 1

a suction pump communicates with the wound or the wound area via a suction line, wherein a wound dressing and an air-tight cover material is provided for air-tight sealing of the wound and the wound area, such that a negative pressure can be generated in the wound region and fluids can be extracted by suction from the wound region

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Implementation Method 2

venting the fluid path of the negative pressure wound therapy system by opening a relief valve

Methodology Applied
Scientific EffectPressure release: Depressurisation

Data Source

PatentEP3511031B1Devices for controlling negative pressure wound therapy
Publication Date: 2023.05.03 PAUL HARTMANN AG
  • EP3511031B1 patent drawingFigure 1
  • EP3511031B1 patent drawingFigure 2a~2b
  • EP3511031B1 patent drawingFigure 2c~2e

AI summary

The present invention relates to a method of determining a blockage condition in a negative pressure wound therapy system during a negative pressure wound therapy. Said method includes generating a negative pressure at a wound site by means of an electrical pump, recording the negative pressure, venting the fluid path of the negative pressure wound therapy system by opening a relief valve, closing the relief valve, determining and recording a negative pressure gradient occurring during the entire ventilation step, reactivating the electrical pump, determining and recording a number of pump turns, which are required to reestablish the negative pressure, and generating a first or a second blockage detection data set. The methods further includes executing a classification algorithm which allows to discriminate an unblocked condition of the negative pressure wound therapy system from a blocked condition of the negative pressure wound therapy system using the generated data sets. The invention further relates to a negative pressure wound therapy system adapted to execute said method of determining a blockage condition in a negative pressure wound therapy system.