NPWT Controller Blockage Detection via Periodic Pressure Cycling

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing wound treatment technologies using topical negative pressure (TNP) therapy face challenges in efficiently managing blockages and leaks in the fluid flow path, which can hinder the effective delivery of negative pressure to wounds.

Innovation Solution

A negative pressure wound therapy apparatus with a controller that distinguishes between blockages and low leaks in the fluid flow path by periodically activating and deactivating the negative pressure source, and using pressure sensors to measure pressure changes, thereby indicating the presence of blockages or leaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the negative pressure source is continuously activated to ensure effective wound treatment, then the therapeutic effect is improved, but the ability to detect blockages and leaks is reduced

Engineering Contradiction:
Improvetherapeutic effectVSAvoidblockage and leak detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The negative pressure source is activated in periodic cycles rather than continuously. During each cycle, the pump operates for a predetermined time period to deliver therapeutic negative pressure, then stops for a predetermined time period to enable detection of blockages and leaks. This periodic operation allows the system to maintain therapeutic effectiveness while creating opportunities for monitoring system integrity.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system incorporates sensors that monitor pressure and flow characteristics during both the active and idle phases of the periodic cycle. This feedback mechanism detects changes in the fluid pathway that indicate blockages or leaks, allowing the system to identify problems while maintaining overall therapeutic reliability through continuous monitoring.

Inventive Principle:
Principle #23Feedback

2Difficulty of detecting and measuring

If the negative pressure source is deactivated to detect blockages and leaks, then the detection accuracy is improved, but the therapeutic continuity is reduced

Engineering Contradiction:
Improveblockage and leak detection accuracyVSAvoidtherapeutic continuity
Core Design Contradiction:
Difficulty of detecting and measuringVSDuration of action of moving object

Solution Approach 1:

The system uses short, predetermined idle periods within an otherwise continuous therapeutic cycle. These brief interruptions are sufficient to allow detection algorithms to identify blockages and leaks, while the majority of each cycle maintains active therapeutic treatment, thus minimizing disruption to therapeutic continuity.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The detection phase is built into the predetermined operational cycle before problems can significantly impact treatment. By scheduling regular detection windows in advance, the system proactively identifies issues before they compromise therapeutic effectiveness, maintaining overall treatment continuity.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If short detection cycles are used to maintain therapeutic pressure, then the therapeutic efficiency is improved, but the detection reliability is reduced

Engineering Contradiction:
Improvetherapeutic efficiencyVSAvoidblockage and leak detection reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system uses multiple sensors that continuously monitor pressure differentials and flow rates even during short detection windows. This multi-parameter feedback approach allows reliable detection of blockages and leaks within brief time periods, maintaining both therapeutic efficiency and detection reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The detection system uses excessive monitoring parameters and multiple sensing points to compensate for the reduced detection time. By gathering more data per unit time through multiple sensors and measurement points, the system achieves reliable detection results within short cycles that maintain therapeutic efficiency.

Inventive Principle:
Principle #16Partial or excessive 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

The apparatus effectively indicates blockages or leaks, ensuring continuous and efficient delivery of negative pressure to wounds, thereby promoting wound healing.

Implementation Method 1

a negative pressure source that can be configured to provide negative pressure via a fluid flow path to a wound covered by a wound dressing

Methodology Applied
Scientific EffectNegative pressure: Vacuum

Implementation Method 2

using pressure sensors to measure pressure changes

Methodology Applied
Scientific EffectPressure measurement:

Data Source

PatentEP3796949B1Systems and methods for determining blockages in a negative pressure wound therapy system
Publication Date: 2025.04.09 T J SMITH & NEPHEW
  • EP3796949B1 patent drawingFigure 1
  • EP3796949B1 patent drawingFigure 2A
  • EP3796949B1 patent drawingFigure 2B

AI summary

A negative pressure wound therapy device can include a negative pressure source and a controller configured to activate the negative pressure source for a first duration of time to attempt to reduce pressure under the wound dressing to approximately ae negative pressure set point, subsequent to expiration of the first duration of time, deactivate the negative pressure source after pressure under the wound dressing is reduced to approximately the negative pressure set point, activate the negative pressure source for a second duration of time to attempt to reduce pressure in the fluid flow path, the second duration of time subsequent to the first duration of time, determine a pressure change in a fluid flow path over the second duration of time, and, in response to determining that the pressure change in the fluid flow path over the second duration of time indicates reduction in pressure, provide indication of a blockage.