What Is Vacuum-Assisted Wound Closure?

Medically Reviewed by Dan Brennan, MD on April 14, 2021
Written by WebMD Editorial Contributors
3 min read

Vacuum-assisted closure is a treatment that applies gentle suction to a wound to help it heal. It's also called wound VAC or negative pressure wound therapy (NPWT). 

‌Negative pressure wound therapy involves a special dressing connected to a pump that gently draws fluid and infection from the wound. A nurse will:

  1. Clean the wound and thoroughly dry the skin around it‌
  2. Place a foam or gauze dressing (bandage) directly on the wound
  3. Cover this dressing with a clear film that seals to the skin around the wound‌
  4. Insert a tube into a small opening in the clear film and connect the other end to a vacuum pump

When the pump is turned on, it creates a very gentle suction that, over time, removes excess fluid from the wound.

Wound VAC therapy promotes healing because it:

Removes excess fluid. Edema, a buildup of extra fluid, is common after surgery. It can cause swelling, increase the risk of infection, and delay healing. Excess fluid can put pressure on the wound and the stitches or staples that hold it closed. Negative pressure wound therapy slowly draws fluid off the wound, relieving pressure and reducing swelling.

Reduces bacteria. Infection is not only dangerous, but it can also keep the wound from healing. The body must focus on clearing the bacteria away from the wound and can’t move on to the next stage of wound repair.‌

Wound VAC therapy helps the body by removing some of the bacteria. This lowers your risk of wound infection and allows healing to move forward.

Improves blood flow. Good perfusion, or blood flow, is needed to bring repair cells to the wound, take bacteria and dead cells away, and deliver oxygen to the area. Removing extra fluid allows for good perfusion, and the negative pressure of wound VAC therapy has been shown to increase the speed at which fluids move through the blood vessels in the area.‌

Encourages growth of repair tissue. To heal the wound, the body creates new tissue that binds the edges of the wound together and fills any gaps. Studies have shown that vacuum-assisted closure stimulates the growth of this repair tissue.

Pulls wound edges together. Wound VAC treatment shrinks the size of the wound and draws the edges of the wound together, making it easier for the body to repair the gap.

Stabilizes the wound. Negative pressure wound therapy keeps the wound still, like a cast keeps a broken bone from moving. This helps the wound heal and prevents reinjury to the area.

‌Wound VAC treatment is ideal for difficult-to-heal wounds, such as:

‌Vacuum-assisted closure is NOT used in wounds that:

  • are actively bleeding‌
  • are cancerous
  • have a lot of necrotic (dead) tissue
  • contain exposed arteries, nerves, or organs

A nurse will change the dressing 2 to 3 times a week, more often if the wound is infected. In some cases, your wound care provider might teach a family member or friend how to change the dressing for you.

The person who changes your dressing should always wash their hands beforehand, wear disposable gloves during the dressing change, and wash their hands again after. 

If someone has a rash or open cut, they should wait until their skin heals before changing your dressing. If you need more help with your wound VAC dressing at home for this or any other reason, talk with your doctor. They may be able to connect you with a home health service or help you find another qualified caregiver.

Depending on the type of wound, changing the wound VAC dressing may hurt some. If dressing changes are very uncomfortable, talk with your doctor about pain relief options.

You cannot bathe or swim with a wound VAC dressing. If the dressing is underwater for long, it may loosen, or the wound may get infected. You can, however, disconnect the pump long enough to shower.

If an alarm sounds on the pump, there may be a leak in the dressing. Call your home health nurse or the clinic where your dressing is changed and ask them to replace the dressing.

Call your doctor if you experience any of the following during wound VAC treatment: