Differences in fluid distribution during negative pressure wound therapy (NPWT) in a large-pored PU-foam dressing, drainage film, and a specialized NPWT dressing system

BackgroundNegative pressure wound therapy (NPWT) has advanced the management of the open abdomen and other wounds. However, using the correct wound filler is essential as the material needs to convey a heterogeneous pressure distribution and create the pressure gradients required to drain interstitial fluid and remove wound exudate. This study compared the differences in fluid distribution during NPWT using a large-pore PU-foam dressing (Suprasorb® CNP foam), drainage film (Suprasorb® CNP drainage film) and a specialized NPT dressing system (KCI ABThera™ NPT system) in vitro.MethodsA tissue model was prepared from gelatine, powdered milk, and tissue marking dye. Each filler/dressing was placed on a tissue model which was connected to a fluid reservoir, linked to a TRAC™ Pad and sealed. The TRAC™ Pad was connected to a vacuum pump set to −120 mmHg for 8 h. An infra-red camera was used to record fluid transport in the dressings.ResultsAll fillers/dressings exhibited a fast fluid distribution and transport during the first hour (gradients 0.97–1.31) and steady state was reached after approximately 160 min. The NPT dressing system demonstrated a distribution limited to 70%, while the PU-foam and the drainage film presented a uniform and complete dispersal of fluid.ConclusionThe results demonstrate that using an appropriate filler/dressing can facilitate effective wound fluid transport and drainage of interstitial fluid by producing heterogeneous pressures at the wound bed.