The VAC technique
Several components compose the Vacuum Assisted Closure System (VAC), says Louis C. Argenta, professor and chairman of the Department of Plastic and Reconstructive Surgery at Bowman Gray School of Medicine in Winston-Salem, NC.
Components of the VAC include:
• medical-grade reticulated polyurethane ether foam dressing whose pores range from 400-600 microns in diameter;
• a noncollapsible evacuation tube that is embedded in the foam;
• an effluent collection canister that is hooked to the proximal end of the tubing;
• a vacuum pump adjacent to the collection canister.
The unit is about the size of a lunch box and weighs less than nine pounds and runs from standard electrical outlets. A portable battery-powered unit weighing about 14 pounds also is available from the manufacturer. The manufacturer, Kinetic Concept in San Antonio, TX, also plans to introduce a lighter and smaller model (about the size of a portable cassette player) next year. The system rents for $75 to $80 a day, according to Kinetic Concepts.
Dressings are trimmed to the appropriate size at bedside and placed in the wound. The evacuation tube is attached to the VAC, and the distal end is positioned so that it exits parallel to the skin’s surface. The surface of the wound is then covered with an adhesive tape, which extends five centimeters beyond the wound margins. This ensures that an air-tight seal is created. When applied, the suction collapses the foam dressing, and because the foam is open-celled, the suction is distributed equally throughout the dressing.
Argenta emphasizes that wounds should be carefully debrided before the use of the VAC because nonviable tissue "becomes a focus for bacterial proliferation and a source of lytic enzymes, bacterial toxins, and other factors that impede wound healing. All nonviable tissue is debrided in the operating room, in the clinic, or at the bedside."1
1. Argenta LC, Morykwas MJ. Vacuum-assisted closure: A new method of wound control and treatment. Annals Plast Surg. In Press.