Large and small wounds which occur as a result of postoperative complications can be treated with VAC therapy after adequate surgical debridement and under appropriate antibiotic prophylaxis. In these wounds, controlled localized negative pressure must be applied to help drawing of wound edges together (KCI, 2007). VAC therapy improves perfusion and provides a closed moist environment which enhances wound healing. It also removes exudate, excess fluids and infectious materials.
Continuous pressure is what is recommended for abdominal and sternal wounds throughout the therapy sessions. For wounds in other areas, intermittent therapy can be started after exudate levels are stable. Where granulation tissue growth is the main aim, intermittent therapy is the preferred option. The target pressures and dressing changes are similar to acute wounds. VAC therapy can used with retention sutures in place, but all parts of the wound, including those under and between sutures, must also be accessed and dressed.
When applying VAC therapy to dehiscence wounds, the size of the foam and its placement should be done properly to achieve reverse tissue expansion. Whenever there is a bowel part at the base of the wound, it should either be covered with omentum or a mesh or bioengineered tissue. Otherwise there is a risk of developing granulation tissue and adhesions (KCI, 2007). Sternal wounds require special care. Before starting VAC therapy, osteomyelitis of the bone must be ruled out.
Continuous therapy with the lowest possible negative pressure is the preferred form of therapy. Dressing changes in deep sternal wounds must be done by specialist surgeon. In those with unstable sternum, continuous negative pressure is preferred so that stabilization of chest wall is achieved. This stabilization causes a splinting effect allowing the patient to be more mobile and comfortable. Graft wounds VAC therapy can be employed after meshed skin graft and bioengineered skin tissue placement.
In these wounds, the purpose of the therapy is to provide stability for the skin grafts and to protect the environment of the wound by minimizing shear forces and removing unwanted excess fluid and exudate. Continuous negative pressure is the best form of therapy that can be applied to graft wounds. The target pressure recommended in case of GranuFoam dressing is 75-125mmHg and for WhiteFoam dressing is 125mmHg and more. Dressing should be removed after 4 to 5 days after tapering off the drainage.