3 The procedure
3.1 The aims of negative pressure wound therapy (NPWT) for the open abdomen include removing infected material and helping nursing care by reducing escape of fluid; its use may also influence the possibility of delayed primary closure.
3.2 NPWT uses a sealed suction system to remove exudate and infected material from the abdominal cavity. The systems and techniques used vary widely, but the underlying principle is that the abdominal contents are covered with a foam sponge or other porous dressing (for example, gauze), with a membrane between the sponge/dressing and the abdominal contents. The entire wound and surrounding skin are covered with an adhesive transparent membrane, which is perforated by a drainage tube attached to the suction system. This applies negative pressure and removes fluid, at the same time preventing escape of fluid, because the membrane adheres to the skin all the way around the wound. A sensing device (a pad placed on top of the foam dressing) may be used to ensure that the prescribed amount of negative pressure is being applied to the wound.
3.3 Several different commercial systems are available for NPWT, each of which requires specific training for safe and effective use. A number of non-commercial systems have also been described.