NPWT Dressing with Moisture Vapor Transmission Rate

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Solution Overview

Problem

Existing portable negative pressure wound therapy (NPWT) systems face challenges in maintaining stability and control, particularly due to rapid saturation of dressings with exudate, leading to reduced wear time and increased frequency of pump activations.

Innovation Solution

A NPWT dressing with a backing layer having a moisture vapor transmission rate (MVTR) between 500 to 3500 g/m2/24h, combined with an absorbent structure and a liquid spreading layer, which improves the stability of the therapy by reducing the workload on the negative pressure source and enhancing exudate management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the dressing uses a high absorbency structure to handle large amounts of wound exudate, then the exudate removal capacity is improved, but the dressing becomes saturated quickly and wear time is reduced

Engineering Contradiction:
Improveexudate removal capacityVSAvoiddressing wear time
Core Design Contradiction:
Quantity of substanceVSDuration of action of moving object

Solution Approach 1:

The invention divides the fluid collection function into two separate components: the absorbent structure within the dressing and a remote canister. The absorbent structure handles initial exudate absorption while the canister provides additional capacity, preventing premature saturation of the dressing and extending wear time without compromising exudate removal capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-location fluid collection system to a distributed system with components at different locations (dressing at wound site, canister at remote location). This spatial separation allows the dressing to remain thin and comfortable while the canister provides extended absorption capacity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If the pump is activated frequently to maintain stable negative pressure, then the pressure control is improved, but the noise and battery consumption increase

Engineering Contradiction:
Improvenegative pressure stabilityVSAvoidbattery consumption
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The invention introduces an air conduit as an intermediary component that allows controlled air entry into the system. This regulates pressure fluctuations and reduces the frequency of pump activations needed to maintain stable negative pressure, thereby reducing battery consumption while preserving pressure stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention modifies the system's pressure dynamics by introducing controlled air flow through the air conduit. This changes the pressure maintenance mechanism from purely pump-driven to a balanced system where air entry compensates for pressure drops, reducing pump workload and energy consumption.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If the backing layer has high moisture vapor transmission rate to allow moisture evaporation, then the wound healing environment is improved, but the system stability deteriorates due to excessive moisture loss

Engineering Contradiction:
Improvemoisture vapor transmissionVSAvoidsystem stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The invention applies different moisture management properties to different parts of the system. The backing layer at the wound interface has optimized moisture vapor transmission to maintain a moist healing environment, while the remote canister provides a drier storage environment for collected exudate, creating local quality differentiation that satisfies both wound healing and system stability requirements.

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 proposed solution enhances the stability and control of NPWT systems, reduces the frequency of pump activations, and prolongs the wear time of the dressing while maintaining effective exudate management and wound healing.

Implementation Method 1

the backing layer has a moisture vapor transmission rate (MVTR) in the range of from 500 to 3500 g/m2/24h

Methodology Applied
Scientific EffectMoisture vapor transmission: Evaporation

Implementation Method 2

an absorbent structure arranged between the backing layer and the adhesive skin contact layer

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP4157176B1A negative pressure wound therapy (NPWT) dressing
Publication Date: 2025.01.29 MOLNLYCKE HEALTH CARE AB
  • EP4157176B1 patent drawingFigure 1
  • EP4157176B1 patent drawingFigure 2a~2b
  • EP4157176B1 patent drawingFigure 3

AI summary

The present disclosure generally relates to a negative pressure wound therapy (NPWT) dressing (100) comprising a backing layer (101), an adhesive skin contact layer (102); the adhesive skin contact layer (102) being configured to detachably adhere the dressing (100) to a dermal surface, wherein the backing layer (101) comprises a coupling member (104); the coupling member (104) comprising a tubing (105) configured to connect the dressing (100) to a negative pressure source and to a remote fluid collection means.