It has been observed that when this therapy is carried out in continuation, the fluid inhibiting the healing is drained out from the wound. As a result of this, the blood flow to this area also increases effectively. Based on the type of wound being treated, the vacuum can either be applied at regular intervals or continuously. Usually, for hygiene issue and better cure, the dressing is changed 2-3 times a week.

The first step here is to cover the wound with a dressing material which will later be sealed with foam using a transparent film. Once this is completed, a drainage tube is attached to this dressing through an opening made in the transparent film. Also, a vacuum tube is fastened to this film with its other end linked with a canister placed on either side of the vacuum pump. This allows the wound to be treated in a closed and controlled environment. Eventually, the excess fluid from the wound is removed and the circulation is also enhanced.

Negative Pressure Wound Therapy (NPWT) not just effectively reduces edema, but it also creates the best healing environment. The technique is commonly carried out with chronic wounds or those which are expected to cause difficulties in healing.

• Open-Cell Foam
• Gauze 
• Transparent Film or Honeycombed Textiles 

Foam Dressing is simply used to fill open cavity wounds. In order to use this for treatment, the material can be cut in accordance with the size of the wound to make a perfect fit. Basically, this is applied to the wound after which the same is draped with a film to ensure the dressing is sealed.

Open Weave Cotton Gauze is yet another dressing material which is used for this therapy. The process of covering the dressing with a transparent film is also similar. Here, the difference is that a flat drain is kept in gauze (sandwiched manner) and thereafter applied on the wound. The drape made using the film ascertains complete seal of the wound following which the drain is fastened to the pump.

Layers of non-woven polyester, connected using a silicone elastomer, has a non-adherent surface for wound contact. These are made up of countless small & semi-rigid dome structures, but in the present time, this is not practically used.

In any of these techniques, when the dressing is finally sealed, the vacuum pump can be attached to deliver pressure (either continuous or intermittent ) which can easily be controlled based on the device you are using. This will vary between −125 and −75 mmHg depending on the patient’s tolerance as well as the material being used for therapy. 

The type of dressing to be used is determined by the type of wound to be treated, clinical objectives and importantly the patient. For those who are sensitive to pain, and have shallow else irregular wounds or wounds with explored tracts, gauze is recommended. On the other hand, foam is used in a tailor-made shape for patient whose wound has a regular outline.

• Untreated osteomyelitis
• Soft tissue malignancy
• Exposed blood vessels, nerves, organs, and anastomotic site
• Malignancy in the wound
• Necrotic tissue with eschar present

Negative Pressure Wound Therapy (NPWT) is a safe and reliable solution to attain the desired results from the treatment. Also, using this, the doctor can effectively accelerate the healing process, especially for acute & chronic wounds.