Table 2.

Description of the basic engineering performance metrics required from a foam dressing that can be quantitatively measured in laboratory settings

Fluid Handling		Mechanical		Biological
Manage a range of viscosities	The dressing should absorb and retain exudate effectively and consistently in terms of volume and mass over the clinically relevant time course, across the entire reported range of possible human biofluid viscosities, without the occurrence of spillovers or pooling	Stiffness	The dressing stiffness should not substantially exceed the skin and subcutaneous tissue stiffnesses relevant to the location, etiology, and severity of the wound, at either its new (straight-from-the-package) condition, or post a usage period, to avoid indentation damage	Permeability to pathogens	The dressing should prevent penetration or release of particulates at sizes representative of bacterial, viral, and fungal pathogens through the external dressing surface
Body position, wound location, and interaction with additional wound care treatments	The dressing should absorb and retain exudate effectively and consistently across all the possible positions of the body and wound with respect to the gravity vector, for example, when the dressing is vertical to the ground (such as when treating a venous leg ulcer), or when the dressing is subjected to sustained or repeated bodyweight forces (as in a nonoff-loaded wound). Addition of external compressive forces, such as during application of multilayer compression bandaging and other forms of leg compression treatments applied for the management of venous insufficiency or venous leg ulcers should minimally affect the absorbency and retention performance of the applied dressing	Strength	The dressing should be durable to the expected compressive, tensile, and shear force magnitudes associated with the bodyweight, including any potential body movements against surfaces (in single or repeated events), and to the pull-out forces when the used dressing is removed, at its new (straight-from-the-package; also considering storage duration and conditions), or post a usage period
Consistent fluid evaporation to the environment	The dressing should constantly and consistently release the retained fluid to the environment, via evaporation, for the ranges of clinically relevant temperatures and humidity values representing the ambient conditions at the potential or the intended geographical regions of use (e.g., in an extremely moist or an extremely dry environment)	Adhesiveness	The borders of the dressing should provide consistent adhesiveness throughout the intended period of use, that is, the dressing should stay in place under the expected regimens of the bodyweight and external forces, as well as under the influence of skin moisture conditions, but should not require excessive peeling forces during removal to avoid periwound skin stripping damage. Contrarily, the wound pad should never adhere to the wound bed (i.e., for the wound pad, measured peeling forces should be extremely low)