Negative pressure therapy is used in

Vaccum assisted closure Known as negative pressure wound closure Applying intermittent negative pressure of approximately - 125mmHg appears to hasten Debridement and the formation of granulation tissue in chronic wounds and ulcers A foam dressing is cut to size to fit the wound A perforated wound drain is placed over the foam and the wound is sealed with a transparent adhesive film. A vaccum is then applied to the drain. Negative pressure may act by decreasing oedema, by removing interstitial fluid and by increasing blood flow As a result bacterial counts decrease and cell proliferation increases thereby creating a suitable bed for graft or flap cover. Ref: Bailey and love 27th edition Pg no :30