NPWT Blockage Detection via Pressure Change Rate Analysis

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Solution Overview

Problem

Current NPWT systems face challenges in reliably detecting blockages in the fluid flow paths, particularly in dual-lumen systems, which can disrupt the negative pressure treatment and require additional components for blockage detection.

Innovation Solution

The proposed solution involves an apparatus with a source of negative pressure, an electronically controllable valve, and a pressure sensor, controlled by circuitry that detects blockages by measuring pressure change rates and responding accordingly to indicate blockages in either the exudate or air lumen.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional pressure sensors and secondary pressure monitoring conduits are added to provide blockage detection functionality, then blockage detection reliability is improved, but device complexity increases

Engineering Contradiction:
Improveblockage detection reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The existing pressure sensor in the NPWT system is made multi-functional by using it for both routine pressure monitoring and blockage detection. The control circuitry utilizes the same pressure sensor to detect both normal pressure changes during therapy and abnormal pressure changes indicating blockages, eliminating the need for additional dedicated blockage detection sensors.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its existing pressure sensing capability to detect blockages without requiring external additional components. The control circuitry analyzes pressure changes from the existing sensor to identify blockage conditions, allowing the system to self-diagnose using resources already present in the NPWT apparatus.

Inventive Principle:
Principle #25Self-service

2Reliability

If dual-lumen NPWT systems are used to separate exudate and air flow paths, then treatment effectiveness is improved, but difficulty in discerning which lumen is blocked increases

Engineering Contradiction:
Improvetreatment effectivenessVSAvoidblockage location identification
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The system segments the pressure detection process into two distinct phases: first opening the electronically controllable valve to detect blockages in the air lumen through pressure changes, then closing the valve and activating the negative pressure source to detect blockages in the exudate lumen. This temporal segmentation allows the single pressure sensor to distinguish between blockages in different lumens.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control circuitry performs a preliminary action by opening the electronically controllable valve before activating the negative pressure source. This preliminary valve opening allows the system to detect blockages in the air lumen first, and only after closing the valve does it activate the negative pressure source to detect exudate lumen blockages, preventing misidentification of blockage locations.

Inventive Principle:
Principle #10Preliminary action

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 enables reliable detection of blockages in NPWT systems, differentiates between blockages in the exudate and air lumens, and potentially reduces energy consumption by optimizing the operation of the NPWT apparatus.

Implementation Method 1

a pressure sensor configured to measure a pressure level in the second fluid flow path

Methodology Applied
Scientific EffectPressure measurement:

Implementation Method 2

a source of negative pressure configured to provide negative pressure via a first fluid flow path from an inlet of the source of negative pressure to a wound site

Methodology Applied
Scientific EffectNegative pressure suction: Suction

Data Source

PatentEP4545111A1Negative pressure wound therapy
Publication Date: 2025.04.30 MOLNLYCKE HEALTH CARE AB
  • EP4545111A1 patent drawingFigure 1
  • EP4545111A1 patent drawingFigure 2~3
  • EP4545111A1 patent drawingFigure 4~5

AI summary

An apparatus and related aspects for providing negative pressure to a wound site are disclosed. The apparatus comprises a source of negative pressure configured to provide negative pressure via a first fluid flow path from an inlet of the source of negative pressure to a wound site, and an electronically controllable valve configured to release negative pressure from the wound site via a second fluid flow path. The apparatus further comprises a pressure sensor configured to measure a pressure level in the second fluid flow path, and control circuitry operatively connected to the source of negative pressure, the electronically controllable valve, and the pressure sensor. The control circuitry is configured to open the electronically controllable valve, and in response to a pressure change rate being above a pressure change rate value, output a signal indicative of a blockage in the second fluid flow path. The control circuitry is further configured to in response to the pressure change rate being below the pressure change rate value, close the electronically controllable valve and activate the source of negative pressure, and in response to the pressure level, as measured by the pressure sensor, being non-responsive to a change in negative pressure generated while the source of negative pressure is active, output a signal indicative of a blockage in the first fluid flow path.