NPWT Dressing Fluid Management for Longer Wear Time

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Solution Overview

Problem

Conventional NPWT dressings for home use suffer from rapid saturation due to excessive wound exudate, leading to reduced wear time and potential system instability, as they lack an optimal balance between absorption and exudate removal.

Innovation Solution

A NPWT dressing with a balanced absorbent structure containing 10-20 mg/cm² superabsorbent particles, a controlled liquid distribution system, and a backing layer with a specific moisture vapor transmission rate, allowing for efficient absorption and removal of exudate while maintaining system stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the dressing absorbs too much wound exudate quickly, then the absorption capacity is improved, but the wear time is reduced due to saturation

Engineering Contradiction:
Improvewound exudate absorption capacityVSAvoiddressing wear time
Core Design Contradiction:
Quantity of substanceVSDuration of action of moving object

Solution Approach 1:

The fluid management system is segmented into two distinct components: the dressing with absorbent structure for local exudate absorption, and a separate remote fluid collection means for continuous exudate removal. This segmentation allows the dressing to absorb exudate without becoming saturated, as the remote collection means continuously removes fluid, thereby maintaining dressing functionality and extending wear time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A tubing system acts as an intermediary between the dressing and the remote fluid collection means, enabling continuous exudate removal while the dressing performs absorption. This intermediary mechanism allows the dressing to maintain its absorption function without becoming saturated, resolving the contradiction between absorption capacity and wear time.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Weight of moving object

If a portable NPWT device with limited pump capacity is used, then the device portability is improved, but the ability to handle large amounts of wound exudate is reduced

Engineering Contradiction:
Improvedevice portabilityVSAvoidwound exudate handling capacity
Core Design Contradiction:
Weight of moving objectVSQuantity of substance

Solution Approach 1:

The system segments fluid management functions between the portable device (negative pressure generation and initial absorption) and a separate remote fluid collection means (continuous exudate removal). This segmentation allows the portable device to maintain small size and weight while the overall system handles large volumes of exudate through the remote collection component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tubing system serves as an intermediary that connects the portable NPWT device to a remote fluid collection means, enabling the small portable pump to effectively manage large amounts of exudate by continuously transferring fluid to the remote collection container, thereby overcoming the pump's limited capacity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Duration of action of moving object

If the dressing is designed for both absorption and exudate removal, then the wear time is improved, but the system complexity is increased

Engineering Contradiction:
Improvedressing wear timeVSAvoidsystem complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The dressing system is designed with multi-functionality: the absorbent structure within the dressing performs both absorption of wound exudate and distribution of negative pressure, while the integrated tubing system enables continuous exudate removal to the remote collection means. This universal design allows a single integrated system to achieve multiple functions (absorption, pressure transmission, and fluid removal), extending wear time without requiring multiple separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 dressing achieves a prolonged wear time of up to 9 days by optimizing liquid distribution between the dressing and remote fluid collection, preventing blockages, and ensuring consistent negative pressure application.

Implementation Method 1

the absorbent structure comprises superabsorbent particles in an amount of from 10 to 20 mg/cm2

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

distribution of wound exudate stored by the dressing

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 3

Negative pressure wound therapy (NPWT) is a technique that promotes healing of e.g. surgical, acute and chronic wounds by the application of a sub-atmospheric pressure to the wound, using a negative pressure pump

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Implementation Method 4

Excess wound exudate is thereby drawn out

Methodology Applied
Scientific EffectSuction: Suction

Implementation Method 5

the adhesive skin contact layer being configured to detachably adhere the dressing to a dermal surface

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 6

a backing layer with a specific moisture vapor transmission rate

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4157175B1A negative pressure wound therapy (NPWT) dressing
Publication Date: 2025.12.10 MOLNLYCKE HEALTH CARE AB
  • EP4157175B1 patent drawingFigure 1a
  • EP4157175B1 patent drawingFigure 1b~1c
  • EP4157175B1 patent drawingFigure 2

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.