Understanding Negative Pressure Wound Therapy

KCI wound d vac

Negative pressure wound therapy (NPWT) is becoming more and more common in clinical practice as the body of evidence supporting its use grows. The KCI wound vac is perhaps the best known of the NPWT devices currently available for commercial use. What exactly does NPWT do, how does it work and who can benefit most from NPWT?

What is NPWT?

Negative pressure wound therapy uses vacuum therapy in the form of a dressing applied to an acute or chronic wound. The vacuum pressure is controlled at a sub-atmospheric pressure and may be intermittent or constant. In NPWT, the wound is covered by a dressing which is sealed and then connected to a vacuum pump.[ssboost]

How does NPWT promote wound healing?

NPWT promotes healing of acute and chronic wounds by:

  • removing infectious materials
  • removing any barriers to cell proliferation/migration, thereby promoting granulation
  • providing a moist, protected wound care bed
  • promoting tissue perfusion
  • removing wound exudate, which can lead to maceration and a delay in wound healing
  • reducing tissue edema (interstitial fluid)

Who Can Benefit from NPWT?

Many of us are probably familiar with the use of NPWT on diabetic ulcers or other chronic, non-healing wounds, where NPWT is used as a “last resort”. However, a wide variety of wounds can benefit from NPWT, including:

  • acute/chronic wounds
  • traumatic wounds
  • dehisced wounds
  • partial-thickness burns
  • pressure ulcers
  • diabetic ulcers
  • grafts and flaps

Many wounds can benefit when NPWT is used earlier, rather than as a measure of last resort.

Is There Anyone Who Should Not Use NPWT?

Patients who have the following conditions would not/should not be considered as candidates for NPWT:

  • osteomyelitis which has not been treated
  • necrotic tissue which has eschar present (eschar must first be removed)
  • malignancy in the wound (i.e. fungating wounds)
  • unexplored and/or non-enteric fistulas

The KCI wound vac is perhaps the most well-known vacuum-assisted closure device currently available. The KCI wound vac has been the subject of more than 850 peer-reviewed articles. What separates the KCI wound care system from its competitors is its Granufoam dressing, which contains thousands of open and reticulated cells that help to promote wound healing and prevent wound infection under an atmosphere of negative pressure.

To learn more about vacuum-assisted closure (vac) therapy, visit KCI.com. If you would like to learn more about wound care in general, Wound Educators offers wound care courses to suit any need.


Suissa, D, Danino, A & Nikolas, A. (2011). Negative-pressure therapy versus standard wound care: a meta-analysis of randomized trials. Plast Reconstr Surg. 2011 Nov;128(5):498e-503e.


  1. Is KCI advertising here? There are many options when it comes to choosing a wound vac. Many that use foam, some that use gauze/drains, and a few that can use either. I have never used a KCI vac in myractice but I assure you that I have had great success with the vacs that I do use.

    1. Hi, thanks for your comment. I agree that there are many options available for negative pressure wound therapy. KCI is not advertising here. We chose to discuss KCI for this particular post, however we will cover other devices in the future.

    2. I am not a practitioner, but have recently been fitted with a KCI wound vac on my inner thigh for a deep crushing wound. A major defect I have found with the portable wound pump is the charging cord. It has a tiny plug which “lightly” fits into the side of the pump. It easily falls out. KCI has retrofitted this plug with a useless Velcro strip which is supposed to hold the plug in. While you are sleeping and supposed to be charging the slightesy movement causes the charging plug to fall out. So when you wake and want to move around with it, it has gone dead overnight, thereby relegating you to be attached to an electric wall plug all day. The portable convenience is lost. They needed a better method of keeping the charge cord plugged into the unit.

      1. I agree. I am also a put withal groin/thigh wound that struggles keeping the changing plug plugged in. I also have some questions about skin prep. If that is s part of propping fir the drape, why is it nit sent with supplies??

  2. Dear Laurie–most of the time your stuff is awesome–this piece is overblown, and does not follow evidence provided by CMS–NPWT is not considered to be that helpful in pressure wounds, either. The best place to apply NPWT is in post-surgical wounds that will need closure by second intention–I have certainly used it with good results on chronic wounds; but the results are not better than those achieved by dozens of other dressings, including Allevyn AG and the like. I also refer you to the article which examined the “studies” done about NPWT–titled “No Healing in a Vacuum.” It was compiled by European researchers, and is quite interesting. THX

    1. Thanks for your comment Letha. A recent study supports your comment regarding the use of NPWT in surgical wounds: Negative pressure wound therapy for management of the surgical incision in orthopaedic surgery. The study concludes: There is a rapidly emerging literature on the effect of NPWT on the closed incision. Initiated and confirmed first with a randomised controlled trial in orthopaedic trauma surgery, studies in abdominal, plastic and vascular surgery with high rates of complications have been reported recently. The evidence from single-use NPWT devices is accumulating. There are no large randomised studies yet in reconstructive joint replacement.”

      Cite this article: Bone Joint Res 2013;2:276–84.

  3. This article does seem like a promo for kci’s wound vac. As we all know, yes, most peer review articles reference Kci’s product as they were the first to commercialize negative pressure wound therapy. However the reference made that Kci’s product is superior due to its foam interface is incorrect since I know first hand most foams are cut from the same factory

    1. Great point Kim. The article does focus on the KCI wound vac as this was the first such device on the market. PubMed has and article that reviews the science behind NPWT, and compares the currently available devices. The article examines the scientific literature supporting the efficiency and application of NPWT in wound healing: The evolution of Negative Pressure Wound Therapy [NPWT]: a review of science, available devices, and evolution in the usage of NPWT.

  4. I have a question on NPWT, AM I correct in understanding that this can be used in stage 4 pressure ulcers down to bone with no osteo present?

  5. KCI is the best NPWT system. I tried others on my patients and went right back to KCI. They deserve to be promoted in every way. I would never use any other vac.

  6. I had a pressure sore on the heel of one foot below the Achilles tendon which had gangrene surgically removed. My doctor ordered the Wound Vac for me. Once the wound as 2 cm by 1.7 cm length and width with less than.2 cm depth my doctor switched to wet to dry treatment. It took about four weeks for it to close the wound that much. It started at 4.3cm diameter and..4 cm depth. I don’t know if that is good or not. I had three bacteria including MRSA, so I have been on IV gentamicin for 5 weeks. The important thing is it seems to have done what the doctor wanted. Works for me..

  7. I have a question. I recently placed a vac on a client with 3 very large wounds on lower leg they ordered 2 vacs for management. Why can’t use just one with bridging all 3 wounds instead of just 2? Yes canister will need more frequent change but he is able to do this. This poor guy has 2 vac and an IV to drag around.

  8. My fathers wound vac therapy is on a continuous loop at first they said it was supposed to be at 100, then the doctor changed it to 125. the nurse recently came today around 11AM to clean and change the black sponge. But I recently checked it because the alarm said there was a blockage and it goes from 0 to 75 to 100 then it goes down to 25. Is there anything I can do to fix it?

    1. Angela,

      All of our courses cover NPWT, but we do not have a course exclusively for NPWT. You can check out related blogs for more info as well:

  9. I was a patient of the KCI Wound Vac. I had a 3′ incision in my right groin that wouldn’t heal and would accumulate fluids the size of an egg. Doctor said we can drain it ever so often but felt leaving it open with the Vac would work better. The wound did heal after almost a year with the Vac but it left an indention like a small crater. I am now using the same type for an open would from a below the knee amputation. I hope it works as well.

  10. , I been placed on my wound vac today my staples had got infected and stuff and I’m new too this mobile kci wound vac can I sleep on my side not where the pumping is at but on my other side

  11. I was put in the wound vac 2 times once back n 2017 it helped some what however I had another operation on the same foot my foot Dr put me on the wound vac once again but this time I think it did more harm than good I kept getting bacterial infection my Dr told me to take the vac off I did now I don’t have any more infections it’s up to the person that’s using the vac to think wether the vac is doin them any good or not yes sometimes it works but it’s good and bad

  12. continuous therapy set at 125 but tonight keeps going from 0 to 150. I don’t know how to change this. Will this hurt the wound care process if it stays on 150 for a longer period.

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