Open-cell polyurethane foam for negative pressure wound therapy

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Solution Overview

Problem

Conventional negative pressure wound therapy devices face issues with foam particles entering the wound, causing irritation and delayed healing, and the need for additional wound contact layers to prevent this often reduces exudate flow and complicates dressing changes.

Innovation Solution

A device using an open-cell polyurethane foam with specific tensile strength after storage in bovine serum, which reduces unwanted foam particle deposition and allows for effective exudate passage without additional wound contact layers, comprising a covering material for airtight closure, a means for connecting a negative pressure source, and the foam dressing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional foam dressings are used in negative pressure wound therapy, then the foam can effectively absorb exudate and maintain negative pressure, but foam particles enter the wound causing irritation and delayed healing

Engineering Contradiction:
Improveeffectiveness of negative pressure therapyVSAvoidfoam particle deposition in wound
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by modifying the tensile strength of the foam material to a specific range (80-300 kPa after 3 days in bovine serum) and controlling the foam density (15-55 kg/m³). These parameter optimizations prevent foam particle detachment while maintaining effective exudate absorption and negative pressure application, thereby resolving the contradiction between therapy reliability and harmful particle deposition.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining polyurethane foam with specific physical and chemical properties, including controlled porosity, optimized tensile strength, and appropriate density. This composite approach creates a foam structure that maintains structural integrity under negative pressure while effectively managing exudate, preventing particle entry into the wound.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If additional wound contact layers are introduced between foam and wound base to prevent foam sticking, then tissue trauma is reduced, but exudate flow is reduced and dressing changes become more complex

Engineering Contradiction:
Improvetissue trauma from foam stickingVSAvoidnumber of dressing layers
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies the extraction principle by removing the additional wound contact layer from the dressing system. Instead, it directly addresses the foam sticking problem through material optimization - specifically by controlling foam density (15-55 kg/m³) and tensile strength (80-300 kPa), which prevents foam from adhering to the wound base while maintaining effective exudate flow and simplifying the single-layer dressing structure.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stress or pressure

If foam is compressed to varying degrees under negative pressure, then effective negative pressure therapy is achieved, but passages for exudate removal are narrowed

Engineering Contradiction:
Improvenegative pressure applicationVSAvoidexudate removal efficiency
Core Design Contradiction:
Stress or pressureVSProductivity

Solution Approach 1:

The patent applies parameter changes by optimizing the foam density to a specific range (15-55 kg/m³) and tensile strength (80-300 kPa after 3 days in bovine serum). These parameter optimizations allow the foam to withstand negative pressure compression while maintaining sufficient porosity and structural integrity for effective exudate flow, thus resolving the contradiction between pressure application and exudate removal efficiency.

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

The solution significantly reduces foam particle entry into the wound, enhances atraumatic properties, ensures sufficient exudate passage, and improves patient compliance by maintaining effective negative pressure therapy without additional layers.

Implementation Method 1

an open-cell polyurethane foam, the open-cell polyurethane foam having special properties, in particular a tensile strength after three days of storage in bovine serum

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

open-cell polyurethane foam

Methodology Applied
Scientific EffectPorosity: Porosity

Data Source

PatentEP2515812B1Use of polyurethan foam in negative pressure wound treatment
Publication Date: 2013.05.08 PAUL HARTMANN AG
  • EP2515812B1 patent drawingFigure 1~2
  • EP2515812B1 patent drawingFigure 3~5
  • EP2515812B1 patent drawingFigure 6

AI summary

The invention relates to a device for the negative pressure therapy of wounds comprising (a) a covering material for the air-tight sealing of a wound region; (b) optionally a means for connecting a source of negative pressure; and (c) a wound dressing, containing an open-cell polyurethane foam, wherein the open-cell polyurethane foam has special properties, in particular a tensile strength after three-day storage in bovine serum, measured according to DIN 53571, of between 80 kPa and 300 kPa. Furthermore, the invention relates to the use of such an open-cell polyurethane foam for use as a wound dressing in the negative pressure therapy of wounds.