Negative pressure wound therapy is a procedure for treating patients with open abdomen (laparostomy) in whom abdominal closure is not or no longer possible or advisable. Traditional indications are abdominal sepsis and abdominal compartment syndrome.
Negative pressure wound therapy in the abdomen is based on the principles of occlusion and negative pressure. Occlusion means that the abdominal cavity is sealed off air- and fluid-tight with a special film dressing, which allows the connection of a pump that creates negative pressure in the abdomen by continuous or intermittent suction. The negative pressure results in the removal of exudate and debris from the peritoneal cavity (drainage effect) and temporary, sutureless dynamic closure of the abdominal wall. Usually, negative pressure wound therapy is known as "vacuum treatment", which is physically incorrect, since only negative pressure and no vacuum is generated [1].
The idea of treating open abdomen by negative pressure goes back to the principle of negative pressure therapy in superficial wounds, which is used with great success in acute and chronic wounds. Negative pressure wound therapy is contraindicated in patients with clinically significant coagulation disorders, untreated osteomyelitis, and malignant wounds, and in exposed organs and blood vessels. Therefore, the usual type of negative pressure wound therapy in acute and chronic wound cannot be used in the abdomens, as the negative pressure in combination with occlusive dressings poses a high risk for small bowel fistula formation. Accordingly, negative pressure wound therapy in the abdomen requires special occlusive dressings with appropriate films, foams, and gauzes [2, 3, 4].
Open abdomen has traditionally been associated with poor outcome and significant patient mortality and morbidity. Local negative pressure wound therapy offers significant benefits over traditional dressings and interventional procedures:
1. Abdominal negative pressure wound therapy reduces the risk of abdominal compartment syndrome because the dressing stabilizes the abdominal wall without traditional suturing [5].
2. Negative pressure wound therapy increases the chances of (subsequent) primary closure of the abdominal cavity, thereby avoiding costly surgical procedures to reconstruct and close the abdominal wall.
3. Negative pressure wound therapy permits prone positioning to improve breathing because the system stabilizes the abdominal wall, which is necessary for diaphragm assistance in breathing. In turn, this facilitates earlier extubation.
4. Compared with traditional management of open abdomen (e.g., with moist abdominal towels or waterproof films), negative pressure wound therapy reduces mortality [6].
5. In "fit" patients, portable NPWT systems permit early mobilization and transfer to a peripheral care unit.