Made EasyMextra® Superabsorbent Made Easy

Mextra® Superabsorbent Made Easy

Complex wounds, Exudate Management, Products | Tickle J, Fletcher J

Mextra® Superabsorbent Made EasyExudate plays an essential role in moist wound healing. However, in chronic wounds high levels of exudate may be associated with malodour, periwound skin damage and strikethough, impacting significantly on a patient’s quality of life. In local wound management, dressings are the main option for dealing with exudate. This made easy discusses Mextra® Superabsorbent (Molnlycke Health Care), and how to use it in the treatment of moderate to highly exuding wounds.

Role of exudate in wound healing
Exudate production is a natural component of the wound healing continuum. It facilitates the diffusion of vital healing factors, such as growth factors, and assists in the migration of cells across the wound surface. It promotes cell proliferation and provides essential nutrients for cell metabolism (White and Cutting, 2006).

A moist environment promotes wound healing (White and Cutting, 2006). However, when a wound produces too much exudate problems can occur including periwound skin damage, an increased risk of critical contamination/infection of the wound, delayed healing, increased levels of matrix metalloproteinases (MMPs), and patient pain and distress (WUWHS, 2007), as well as a drain on clinicians' time and resources. Patients can also experience anxiety, fear and social isolation due to the malodorous, unmanageable leakage from wound dressings (Tadej, 2009; Gebhardt, 2010).


Role of dressings in exudate management

In wounds producing too much exudate, choosing an appropriate dressing, such as a foam or superabsorbent that can absorb excess fluid is key (WUWHS, 2007). Exudate is absorbed into the dressing's matrix but when exudate levels exceed its absorbent capacity subsequent periwound maceration and potential excoriation can occur (Queen, 2010), affecting patient comfort and quality of life (Adderley, 2008).
Inaccurate assessment, inappropriate dressing selection and over estimating wear time can therefore lead to poor management of exudate. Key characteristics of an ideal absorbent dressing are: absorption and retention of exudate, prevention of exudate from coming into contact with the periwound skin, easy removal, conformability, cost efficiency and efficacy underneath compression.


What is Mextra® Superabsorbent?

Mextra® Superabsorbent is a highly absorbent non-adhesive dressing designed for use in wounds associated with moderate to high levels of exudate.
The dressing's four-layer construction works in a sequence to optimally manage exudate (Figure 1). The outer layer is a non-woven, fluid-repellent (hydrophobic) polypropylene membrane (1, in Figure 1). The core absorbent layer (2) is a pad comprising a three-dimensional structure containing precisely controlled proportions of cellulose (cotton) fibres and bonding fibres with embedded polyacrylate superabsorbent particles. A polyester and viscose non-woven distribution layer (3) lies between the superabsorbent layer (2) and the fluid-attracting (hydrophilic) polypropylene spun-bonded non-woven wound contact layer (4).


The design of Mextra® Superabsorbent offers the following attributes:

  • Absorbs and retains exudate
  • Maintains its structure (size and volume) without becoming bulky
  • Keeps the outer layer dry
  • Provides protease modulating activity in the form of the polyacrylate superabsorbent particles, which have been associated with protease modulation (Eming et al, 2008).
  • Good conformability.


How Mextra® Superabsorbent works

The dressing's ability to manage exudate stems from the complimentary functions of its four layers:

  • Fluid acquisition: The hydrophilic wound contact layer transfers wound exudate upwards towards the core of the dressing, ensuring the wound is not too wet.
  • Distribution: The distribution layer evenly transfers exudate laterally and upwards into the absorbent core for maximum absorbency.
  • Absorption and retention: This core contains the right proportion of superabsorbent particles to absorb exudate without causing the dressing to become bulky and heavy. As the superabsorbent particles in the core absorb exudate they occupy the structure of the pad. There must be sufficient space between the superabsorbent particles to allow excess moisture vapour to pass through the backing layer, otherwise dressing breathability is impeded.
  • Protection and comfort: Moisture vapour is transmitted through the outer backing layer but fluid cannot pass through, thus minimising the risk of exudate strikethrough and preventing external fluids from contaminating the wound.


Evidence of efficacy

  • Absorbency
  • Laboratory tests undertaken by an independent body have shown that Mextra® Superabsorbent has a high absorption capacity, which is comparable to other superabsorbent dressings (Molnlycke Health Care, 2011).

 

Retention: use under compression
To effectively prevent periwound maceration and excoriation, a dressing must also retain exudate under pressure comparable to that produced by compression bandages for venous leg ulcers (Cutting and White, 2002). In laboratory tests, the pressure typically exerted by compression bandages for venous leg ulcer management (Grey et al, 2006; Partsch et al, 2008) was applied to Mextra® Superabsorbent that had been saturated with fluid. It retained 95% of the absorbed fluid, and did not disintegrate or become swollen and bulky (Molnlycke Health Care, 2011).


Breathability
The moisture vapour transmission rate (MVTR) of the outer layer was independently evaluated (Mölnlycke Health Care, 2011). Tests showed that a high volume of water evaporated through the backing layer, augmenting the dressing's ability to handle fluid. The backing layer also blocks the passage of water which enables the dressing to prevent strikethrough and keep its outer surface dry.


Protease modulation
MMPs are necessary for wound healing, but if they are present and their activity is too high for too long, they can have a detrimental effect on the extracellular matrix, impeding or arresting wound healing. Managing protease levels is essential for healing. Polyacrylate superabsorbent particles have been shown to reduce MMP levels (Eming et al, 2008) and Mextra® Superabsorbent contains similar particles.


When to use Mextra® Superabsorbent

When the absorbency of a traditional foam dressing is insufficient clinicians may need to look for alternatives. Superabsorbent dressings offer increased absorbency and can be used for:

  • Wounds exuding excessively that have or might lead to infection. This can result in wet and stained dressings, malodour, too frequent dressing changes and poor quality of life for the patient.
  • Moderate to heavily exuding wounds that are not healing.
  • Patients with heavily exuding wounds that are undergoing compression therapy.

Failure to correctly assess and implement an effective dressing regimen has resulted in patients reverting to the use of plastic bags, or the equivalent, to prevent their dressings leaking (Figure 2). Therefore the suitability of the superabsorbent dressing for use underneath compression therapy is important to prevent such episodes of poor management. However, further research into the effect of superabsorbent dressings on sub-bandage pressure is needed (Cook, 2011).

  • Wounds in which existing dressings are failing to contain exudate.
  • Wounds that require maintenance of the correct moisture balance.

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