How should clinical wound care and management translate to effective engineering standard testing requirements from foam dressings? Mapping the existing gaps and needs

Advances in Skin and Wound Care 2022 doi:10.1089/wound.2021.0173 [Epub ahead of print]

Gefen, A., Alves, P., Beeckman, D., Cullen, B., Lazaro-Martinez, J.L., Lev-Tov, H., Najafi, B., Santamaria, N., Sharpe, A., Swanson, T., Woo, K.

Introduction

• The laboratory and clinical performance of wound dressings is dependent on the materials they are made from, their microarchitecture, and how they are constructed.

Aims

• To review and describe the relationship between the structure and function of wound dressings.
• To discuss the translation of clinical wound management into effective, standard testing requirements from dressings to achieve the desirable performance in supporting healing and improving patients’ quality of life.

Methods

• Multidisciplinary review undertaken by the International Wound Dressing Technology Expert Panel (IWDTEP).
• Focus on foam dressings.

Key findings/recommendations

• Foam dressings are not all the same; their performance is based on their specific material composition and construction.
• To be clinically effective, a foam dressing must be able to handle a wide range of exudate viscosities associated with different wound aetiologies, or with the same wound at different stages of healing.
• Current standard tests typically use aqueous solutions (with different salt levels), without proteins to evaluate dressing performance in the laboratory; this is unrealistic and not representative of wound complexity.
• Although the use of protein-containing and viscous test fluids are reported, they are not included in the EN 13726-1 standard and, therefore, not generally considered by those involved in making decisions about dressing choice.
• Bioengineering-based research into dressing efficacy (e.g. by measuring ranges of exudate viscosities for various wound types and different stages of healing) is essential to establishing standards for test fluids.
• The development of a range of exudate substitute fluids capable of representing the diversity of wound exudates is key to clinically-relevant laboratory testing and the formulation of new testing standards.
• Finding the balance between feasible, robust and reproducible laboratory testing of dressings versus the need to consider the vast clinical complexity is a challenge.
• Collaboration between academia, clinicians and industry will be key to the development of realistic, yet practical, laboratory tests that are relevant to clinical practice (i.e. taking into consideration different wound aetiologies, patient characteristics and underlying pathologies).
• Having mapped the gaps between existing test standards for dressings and the clinical setting, the IWDTEP recommends that, for foam dressings, laboratory testing must be designed to quantitively acquire the performance metrics shown in the table below.

Table: Performance metrics required from foam
dressing which can be quantitatively measured in
the laboratory. The listed parameters form the
basis of a core conceptual framework for the
design and evaluation of new and existing foam
dressings.

• Foam-based dressings (and other types) may be challenged in terms of fluid management (e.g. by viscous exudates), or prove to be overtly stiff for the wound care regime (e.g. compression therapy), hence the importance of selecting specific dressings for the required tasks.
• The main types of foam used in dressings are polyurethane (PU) and polyvinyl alcohol (PVA). Of the two, PU foams generally exhibit more uniform pore sizes and better connectivity between the pores, as well as less swelling and hence lower stiffness when wet. As well as implying that PVA foam dressings should not be used under compression therapy, these observations exemplify that foam dressings may vary in their clinical performance, depending on their materials and microstructures.
• Dressing-associated pain may be related to adherence of the dressing to the wound bed, peri-wound skin stripping during removal, or failure of the dressing to manage exudate leading to pooling or spillover of the exudate, and tissue maceration.
• Compared to dressings incorporating traditional adhesives in their design, those with soft silicone wound/skin interfaces can minimise trauma to the wound bed and surrounding skin, thereby reducing pain and discomfort.
• Clinicians should adopt proactive, critical thinking and acquire about the specifications of foam dressing technologies that are available to them
• Laboratory test data should be requested from manufacturers to verify that the dressings being considered are capable of handling the exudate relevant to the wounds that are being treated (e.g. expected exudate volumes, flow rates and viscosities)
• Requiring manufacturers to agree upon and implement testing standards will lead to informed clinical decisionmaking regarding the selection of the safety and best performing foam dressings; in turn, this will impact positively on patient safety, quality of care and overall cost-effectiveness of treatment.

Conclusions

• For optimal wound care, it is essential to use dressings that effectively absorb exudate, are resistant to the mechanical and biochemical wound environment, remain in place for the required treatment period but easily removed, and acceptable to both patients and health care professionals.
• The development of clinically-relevant laboratory test standards that result in comprehensive performance metrics is crucial to gaining clinicians’ trust in dressings.
• Clinically-relevant testing standards would facilitate objective, standardised and quantitative comparisons of different dressings, leading to informed treatment decisions and, thus, to be better patient outcomes.

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How Should Clinical Wound Care and Management Translate to Effective Engineering Standard Testing Requirements from Foam Dressings? Mapping the Existing Gaps and Needs

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