Comparison of Local Saturation for Foam Dressings: A Clinically Relevant Measure of Capacity

The capacity of foam dressings is often described in terms of bulk absorption, which is a measure of the amount of fluid that the dressing absorbs after being submerged in a liquid [1].  While this is an accurate measurement from a scientific standpoint, it does not accurately reflect the necessary performance in a clinical setting.  Bulk absorption does not take into account that traditional foam dressings saturate locally at the wound and need to be changed before reaching the bulk absorption.  A more accurate measurement is the clinically relevant capacity, which is defined as the volume of exudate absorbed before the foam dressing needs to be changed.  A test method was developed to quantify the clinically relevant capacity where simulated wound fluid is delivered at a controlled rate to the wound contact side of the dressing and the volume delivered is recorded when: 1) the surface of the simulated wound bed becomes saturated (strikeback) and 2) SWF begins to leak from the edges of the foam.  This method was used to compare three commercially available foam dressings: soft silicone polyurethane foam dressing (SSP), adhesive hydrocellular foam dressing (AH), and Active Fluid Management^® foam dressing (AFM).  The AFM^® dressings had a greater clinically relevant capacity (15.3 mL ±0.9) than both the SSP dressings (7.134 mL ±1.5) and the AH dressings (5.32 mL ±0.31) even though the bulk absorption of these dressings is similar.  The differences in these data demonstrate the need to reevaluate how foam capacities are compared.