Introduction:

Vacuum assisted closure (VAC) therapy is a commonly used method in the treatment of difficult-to-heal wounds. One way to protect tissue from direct contact with a porous polyurethane sponge is to use a dressing between the sponge and the wound. This layer is called the contact, intermediate or protective layer. The aim of the study was to assess the effect of the presence of the intermediate layer on the effectiveness of VAC therapy.

Material and methods:

Three identical, life-size head and neck models made of silicone were used for the experiment. In each model, a wound was made in the area of the mandibular angle. A negative pressure dressing with an intermediate layer (standard mesh dressing) and without it was used. Then, fluids of different densities were administered to the bottom of the wound. The assessment was made for negative pressure values of –80 mm Hg and –120 mm Hg, analyzing the time from the start of administration to the complete drainage of secretions.

Results:

The increase in fluid density significantly prolonged the time of secretion drainage when using an intermediate layer. The difference was significant for the applied pressures of –80 mm Hg and –120 mm Hg compared to the model without an intermediate layer. In the case of a fluid with a lower density, no significant differences were found in the time of secretion drainage from the wound without or with the use of an intermediate layer.

Conclusions:

The presence of the intermediate layer makes it difficult to drain thick secretions regardless of the vacuum pressure used.