Moisture Management in Wound Care: Highlighting MVTR in Films

A wound can be described or defined in many ways: by its source, anatomical location and appearance, whether acute or chronic, by presenting symptoms, and by the method of closure. In fact, all of these descriptions serve a critical purpose in the assessment and appropriate treatment and management of the wound. Successful wound management seeks symptom resolution and, if viable, complete healing. Managing skin wound care involves supporting the damaged tissue by promoting restoration through the formation of connective tissue and re-growth of the epithelium. Optimum conditions for wound healing involve creating a desirable micro-environment in which ideal moisture content is one of the most important factors.

Researchers focusing on the moisture vapor transmission rate (MVTR) in transparent film dressings have recorded findings while investigating the physical properties of wound dressings that may influence the wound healing process. They propose that a suitable wound dressing is essential in controlling water evaporation from a wound in order to maintain the optimal moisture to promote healing.

The role of Transparent Film Dressings in MVTR

Transparent film dressings are polymer membranes, typically thermoplastic polyurethane products (TPUs), of varying thicknesses coated on one side with an adhesive. The key elements of these dressings are:

• Transparency 
• Impermeability to liquid, water, and bacteria.
• Permeability to moisture vapor and atmospheric gases.
• Biocompatibility.
• Flexibility to conform to body contours with a low profile.
• Ability to prevent moisture build-up under dressings to avoid peel-off.

In order to meet the challenges inherent in wound care, leaders in this industry have developed highly specialized products. They have produced TPUs with a broad range of MVTR and O2 transmission rates. 

Lubrizol LifeSciences is a technology leader and one of the largest providers of engineered polymers, applying their technical expertise of specialty TPUs to develop innovative wound care treatments. 3M's Tegaderm has long been the standard for transparent film for catheter securement and advanced wound care applications. 

A New Development in Moisture Control for Wound Care

Properly managing wound care throughout the healing process involves understanding the importance of monitoring and adapting the dressing to the changing wound exudate. In one study, research showed that wounds that were treated with inappropriate exudate management dressings were found to be less likely to heal in three months compared with wounds receiving appropriate dressings.  

They found that a newly reformulated dressing differed from its predecessor by incorporating a new "moisture control layer" that modulates moisture vapor permeability through the film backing under varying wound conditions. Under low exudating conditions, the dressing retains moisture within the wound. In contrast, under high exudating conditions, the dressing absorbs the moisture quickly and releases the excess from the dressing via evaporation.

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Materials with a High MVTR

The dissolution and permeation of liquids, gases, and vapors in and through thin layers of films (polymers) is a crucial factor for many biomedical applications. All polymers are permeable to fluids, however to what extent depends on the nature of the polymer and the fluid.

Researchers concluded a medium-permeability PU membrane significantly accelerated wound healing compared with other groups. While their experiment involved studying a mouse wound healing model, they are hopeful that their findings may be helpful in guiding the design of wound dressing for wound regeneration in the future.