[1] The vacuum may be applied continuously or intermittently, depending on the type of wound being treated and the clinical objectives.

[7] Following increased use of the technique by hospitals in the US, the procedure was approved for reimbursement by the Centers for Medicare and Medicaid Services in 2001.

[8] General technique for NPWT is as follows: A dressing or filler material is fitted to the contours of a wound to protect the periwound and the overlying foam or gauze is then sealed with a transparent film.

[9][10] There are four types of dressings used over the wound surface: foam or gauze, a transparent film, and a non-adherent (woven or non-woven) contact layer if necessary.

Once the wound is filled, then a transparent film is applied over the top to create a seal around the dressing.

[19] The review concluded "There is now sufficient evidence to show that NPWT is safe, and will accelerate healing, to justify its use in the treatment of diabetes-associated chronic leg wounds.

[citation needed] A reduction in systemic (e.g. interleukins, monocytes) and local mediators of inflammation has been demonstrated in experimental models, while decreased matrix metalloproteinase activity and bacterial burden have been documented clinically.

[citation needed] In vivo, NPWT has been shown to increase fibroblast proliferation and migration, collagen organization, and to increase the expression of vascular endothelial growth factor and fibroblast growth factor-2, thereby enhancing wound healing.