The effect of temperature and humidity on the permeability of film dressings

The moisture vapour permeability of a dressing can make an important contribution to its overall fluid handling capacity. Despite the fact that this parameter is often quoted in scientific literature and manufacturers' promotional material, it is a concept that is not generally well understood. In particular, the effect of changing environmental conditions upon experimentally determined permeability values for particular dressings is rarely acknowledged. The present study was undertaken to derive and validate a method that could be used to predict the permeability of a self-adhesive semipermeable film dressing under specific conditions of temperature and humidity using a single set of data generated in the laboratory. A calculator that facilitates this process is also described.