Defining wound bed conformability: a new testing methodology to assess the relative swelling rise of foam dressings.

OBJECTIVE: Using a dressing that expands and conforms to the wound bed upon exudate absorption is one of the best ways to promote wound healing. While many products claim wound bed conformability, no externally replicated or verified test methodology had been developed to quantify a wound dressing's ability to conform to the wound bed. The Relative Swelling Rise (RSR) test methodology was developed to measure the relative swelling rise of foam dressings upon fluid absorption, and offers a quantifiable and easily replicated method to measure wound bed conformability. METHOD: The RSR test method was developed, validated and reliability tested by Coloplast A/S, Denmark. External replication was provided by ALS Odense, Denmark (previously DB Lab). Circular fences provide a fixed diameter to apply and contain the fluid and prevent horizontal spreading in the test set-up. The swelling height is quantified relative to the fence's inner diameter, i.e., the ratio alpha (α), and allows evaluation of a material's ability to conform to the wound bed. RESULTS: Biatain Silicone foam products (n=3, Coloplast A/S, Denmark) were tested, all afforded an average α-ratio from 0.30 to 0.60. The relative standard deviations were between 1-3%, demonstrating the strength of the test. Robustness of the methodology was demonstrated through the internal validation study, the reliability study, and both an internal and external replication study, as well as a systematic literature review and expert review of the construct, content, criterion and generalisability of the method. CONCLUSION: Having a validated, effective and easily replicable testing method to quantify wound bed conformability of foam dressings is an important step towards achieving better healing outcomes.