Dual-Layer Foam Wound Dressing for Vacuum Therapy

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Solution Overview

Problem

Conventional wound dressings used in negative pressure therapy do not adequately address the varying requirements of different wound healing phases, leading to issues such as clogged pores, maceration, and infection, particularly in the initial cleaning phase, and may not be suitable for sensitive tissue areas or later healing phases.

Innovation Solution

A dual-layer wound dressing with permanently connected first and second porous foams, each with distinct structural properties such as cell count, bulk density, and compressive strength, featuring continuous openings for enhanced exudate drainage and adjustable use based on wound phase, allowing for phase-appropriate treatment with a single dressing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single-type porous foam wound dressing is used throughout all wound healing phases, then the dressing structure remains consistent and easy to manufacture, but it cannot adequately address the varying requirements of different wound phases leading to clogged pores, maceration, and infection

Engineering Contradiction:
Improveadaptability to different wound healing phasesVSAvoiddressing structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The wound dressing is segmented into multiple layers, each with different foam structures optimized for specific wound healing phases. The first layer has a first foam structure suitable for the inflammatory phase, while the second layer has a second foam structure suitable for the proliferative and maturation phases. This segmentation allows each layer to perform its specific function optimally without compromising the overall dressing performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the wound dressing have different foam properties tailored to local requirements. The first layer uses foam with specific porosity and cell structure for effective exudate absorption in the inflammatory phase, while the second layer uses foam with different properties for maintaining a moist environment in later phases. This local quality differentiation resolves the contradiction between adaptability and complexity.

Inventive Principle:
Principle #3Local quality

2Reliability

If foam with high porosity is used to prevent pore clogging in the cleaning phase, then exudate drainage is improved, but the foam may be too soft and lack structural support for sensitive tissue areas

Engineering Contradiction:
Improveexudate drainage reliabilityVSAvoidfoam structural support
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The dressing is divided into functional layers where the first layer uses high-porosity foam optimized for exudate drainage during the inflammatory phase, while the second layer uses foam with different properties providing structural support. This segmentation allows the system to achieve both high drainage reliability and adequate structural strength without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wound dressing employs a composite structure combining different foam materials with complementary properties. The first foam layer provides superior exudate wicking and drainage capabilities, while the second foam layer contributes structural integrity and mechanical support. This composite approach resolves the contradiction between drainage reliability and structural strength.

Inventive Principle:
Principle #40Composite materials

3Strength

If a dense foam structure is used to provide structural support, then the dressing maintains shape and support, but pores become clogged during the cleaning phase causing maceration and infection

Engineering Contradiction:
Improvefoam structural supportVSAvoidpore clogging leading to infection
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The dressing structure is segmented into two functional layers: the first layer uses dense foam providing structural support and shape maintenance, while the second layer uses foam with optimized porosity for preventing pore clogging and maintaining drainage patency. This segmentation allows the system to simultaneously achieve structural integrity and prevent harmful pore clogging.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different foam densities are applied locally within the dressing structure. The first layer employs denser foam where structural support is critical, while the second layer uses more open-pored foam in regions where drainage prevention is paramount. This local differentiation of foam quality resolves the contradiction between structural support and pore clogging prevention.

Inventive Principle:
Principle #3Local quality

4Adaptability or versatility

If the wound dressing is designed with multiple layers for phase-appropriate treatment, then adaptability to different wound phases is improved, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvephase-appropriate treatment capabilityVSAvoidmanufacturing process simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The multi-layer dressing is manufactured by segmenting the production process into distinct steps for each layer, allowing optimization of each layer's foam properties independently. This segmented manufacturing approach enables phase-appropriate treatment capability while managing manufacturing complexity through systematic process design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The manufacturing process merges multiple foam formation steps into an integrated production line where layers are sequentially created and bonded. This combining of manufacturing operations achieves phase-appropriate multi-layer structure while maintaining manufacturing efficiency through process integration and automation.

Inventive Principle:
Principle #5Merging (Combining)

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 dual-layer wound dressing ensures reliable exudate drainage and even pressure distribution across all wound phases, improving healing outcomes and reducing complications like infection, while being adaptable to different wound areas and phases, thus enhancing clinical efficiency and patient comfort.

Implementation Method 1

Both layers are channel-like and completely penetrated by a large number of continuous openings

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a negative pressure is generated in the wound space using a drainage tube and a vacuum pump

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Data Source

PatentEP3139877B2Foam-type wound dressing for vacuum therapy
Publication Date: 2023.07.05 PAUL HARTMANN AG
  • EP3139877B2 patent drawingFigure 1~2
  • EP3139877B2 patent drawingFigure 3a~3b

AI summary

The present invention relates to a wound dressing for use in vacuum therapy of wounds, comprising a first layer composed of a first porous foam, a second layer composed of a second porous foam, wherein the second layer is connected non-releasably to the first layer, a multiplicity of through-openings which pass like channels all the way through both layers, characterized in that the first foam differs from the second foam in terms of the chemical composition of the foam and/or in terms of a property of the foam including the cell count, measured in cells per inch, the apparent density measured according to DIN EN ISO 84, the compression load deflection measured according to ISO 3386-1, the elongation at break measured according to DIN 5357, wherein the wound dressing, as used in vacuum therapy, can be introduced into the wound with its first layer pointing towards the wound base or with its second layer pointing towards the wound base, depending on the choice made by the user.