NPWT Dressing with Hydrophilic Ring for Maceration Prevention

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Solution Overview

Problem

Existing absorbent NPWT wound dressings can lead to skin maceration due to the presence of wound exudate, which slows healing and increases infection risk.

Innovation Solution

An apparatus for negative pressure wound therapy comprising a cover layer with an opening for connecting to a negative pressure source, a porous hydrophobic layer to transmit pressure, and a porous hydrophilic ring around the perimeter to prevent fluid transmission during pressure application and allow it during pressure release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If absorbent NPWT wound dressings are used to collect and retain wound exudate, then wound exudate collection is improved, but skin maceration occurs leading to increased pain and slower healing

Engineering Contradiction:

Improvewound exudate collectionVSAvoidskin maceration

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The wound dressing is divided into functionally distinct zones: a central treatment zone with hydrophobic material for NPWT application and exudate collection, and a peripheral zone with hydrophilic absorbent material for exudate absorption. This segmentation allows each zone to perform its specific function without interfering with the other, preventing maceration while maintaining effective exudate collection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different materials with specific properties are applied to different locations within the wound dressing. The central area uses hydrophobic material to maintain negative pressure and collect exudate, while the peripheral area uses hydrophilic absorbent material to absorb excess exudate and prevent skin maceration. Each location has optimized material properties suited to its specific function.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If absorbent materials are positioned around the perimeter to absorb exudate, then skin maceration is reduced, but negative pressure transmission to the wound site may be compromised

Engineering Contradiction:

Improveskin maceration preventionVSAvoidnegative pressure transmission

Core Design Contradiction:

Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The dressing structure separates the pressure transmission function (central hydrophobic zone) from the exudate absorption function (peripheral hydrophilic zone). This segmentation ensures that absorbent materials do not interfere with negative pressure transmission to the wound site, while still providing maceration prevention at the periphery.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Hydrophobic material is specifically positioned in the central treatment zone to ensure optimal negative pressure transmission and exudate collection, while hydrophilic absorbent material is positioned in the peripheral zone where maceration prevention is most critical. This localized material placement optimizes both pressure transmission and maceration prevention without compromise.

Inventive Principle:

Principle #3Local quality

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 reduces skin maceration by limiting fluid absorption during negative pressure therapy, thereby promoting faster wound healing and reducing infection risk.

Implementation Method 1

a porous hydrophobic layer positioned beneath the opening, the porous hydrophobic layer configured to transmit negative pressure to the wound site

Methodology Applied

Scientific EffectNegative pressure transmission: Pressure Gradient

Implementation Method 2

a porous hydrophilic ring positioned around a perimeter of the porous hydrophobic layer, the porous hydrophilic ring configured to prevent fluid transmission when negative pressure is transmitted through the opening

Methodology Applied

Scientific EffectHydrophilic capillary barrier: Capillary Action

Implementation Method 3

allow fluid transmission when negative pressure is not being transmitted through the opening

Methodology Applied

Scientific EffectHydrophilic absorption: Absorption (physical)

Data Source

PatentEP4041156B1Apparatuses and methods for negative pressure wound therapy with switcheable fluid management

Publication Date: 2025.04.30 T J SMITH & NEPHEW

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AI summary

Disclosed embodiments relate to wound therapy apparatuses and methods for use in negative pressure wound therapy (NPWT). Such wound therapy apparatuses and methods may reduce maceration during NPWT. The wound therapy apparatus may include a porous hydrophobic layer surrounded by a hydrophilic ring. The hydrophilic ring may serve to prevent passage of liquid while negative pressure is applied to the wound, but allow liquid passage to an absorbent ring when negative pressure is no longer applied. A transmission layer may also be included, underlying the absorbent layer.