By Beth Hawkins Bradley RN, MN, CWON

How did you acquire your knowledge and skills around the application of NPWT dressings? Most of us learned by observing another clinician doing dressing applications, or from a manufacturer's representative. We likely just imitated what they did, largely winging it. In my work over the past few years, I have been surprised to learn that many excellent clinicians have gaps in technical ability. This article is intended to review principles of NPWT dressing application to increase the accuracy of your techniques. These tips are distilled from principles that are typical of manufacturer guidelines. It is always recommended that you read and follow the manufacturer’s guidelines for the product that you are using.

1. Cleanse the wound thoroughly prior to each dressing application. Evidence indicates that NPWT does reduce wound bacterial load, and cleansing the wound thoroughly will help in that effort. Additionally, cleansing will remove debris that can clog foam or feed bacteria. Irrigation across the wound bed is great, but remember to irrigate hidden dead spaces such as tunnels and undermined areas.
2. Remove devitalized tissue before starting NPWT. One of the contraindications for NPWT is undebrided eschar. Technically NPWT is not contraindicated when slough is present. However, slough can impact the distribution of negative pressure across the wound bed as well as provide "food" for bacteria, so it is usually recommended to remove as much slough as possible before beginning NPWT. Some clinicians have developed the habit of using an enzymatic debriding ointment underneath the foam. This is a costly addition, and likely has minimal impact on the slough, as the enzymes need to be in contact with the base of the slough for sufficient time to break it down. When NPWT is applied, the ointment is pulled away from the base of the wound, and can clog the foam. You would be better off to spend a few extra days on vigorous mechanical cleansing before starting NPWT.
3. Use appropriate skin preparation techniques based on the needs of the individual. Some clinicians are OCD when it comes to skin protection under NPWT dressings. They will apply an elaborately prepared border of drape over skin coated with multiple layers of skin protectant. Only doing what is needed to protect the skin will save time and money. Many patients require only a light coating of protective barrier wipe. Also, there is no need to use the non-sting formulas on intact skin.
4. Change your mind about the way that tunnels are filled. Tunnels need to be filled to prevent closure in the forward part of the tunnel and prevent seroma formation in the base of the tunnel. Instead of filling the entire tunnel, use the principle of placing a "wick" in the tunnel. This "wick" will extend the entire length of the tunnel, but allows the tunnel to collapse onto it, encouraging the tunnel to close faster. This wick may be made of gauze packing strip, non-adherent contact layer, or white foam. If white foam is used, make sure that the tensile strength is sufficient to prevent breakage upon removal. Always ensure that the tunnel filling material is long enough to be visible in the open wound base.
5. Don't overfill undermined areas. The principle here is much the same as those for filling tunnels. Don't "stuff" them, as the pressure from the foam can delay closure. If the foam you use is too thin, the tensile strength is reduced. You may need to wrap the thinned foam in a single layer of gauze or non-adherent contact layer in a sling like fashion. This ensures that you get out what you put in.
6. Fill the open wound with the right amount of foam. Compressing the foam, placing it into the wound, and then allowing it to expand places excessive pressure on the wound edges, which can delay wound contraction. The foam should be as exact a fit as is possible. This can be tricky with irregularly shaped wounds. It may be helpful to precut foam into a spiral, and then shape it into the wound.
7. Does foam really need to be thinned? Many clinicians assume that shallow wounds should be filled with thinned foam. Manufacturers construct foam of a certain thickness so that it will compress under pressure but still allow moisture to move through. When foam is thinned, foam can over collapse as negative pressure is achieved. This will prevent proper distribution of negative pressure and movement of fluids through foam. Thinning foam also increases the release of foam "crumbs" into the wound.
8. Make sure your bridge is wide enough. Just as thinned foam can over collapse, a narrow bridge can also over collapse. When constructing a bridge out of dressing foam, make sure that it is 1 1/2" wide. This will prevent over collapse.
9. Don't stretch that drape! It is tempting to pull drape very tight when applying it over foam and onto skin so that wrinkles do not develop. Avoid the temptation to stretch the drape, since it can put traction on the skin and cause blisters.
10. Use NPWT as a tool. Many clinicians apply NPWT dressings, turn the pump on, and never give a thought to using anything other than the device’s default settings. Each time the dressing is changed, consider what pressure and mode are called for. For example, continuous mode is often called for during the initial days of NPWT, but moving into the intermittent mode after a week or two may speed granulation. After a time, returning to continuous may be useful.

Finally, here is a bonus tip. Count and document the number of foam pieces that are placed and removed from the wound at each dressing change. It is not sufficient to write this data on the drape covering the wound. Place the count in your wound notes. Check to make sure the counts match at each dressing change. This protects both the patient and you!

About the Author
Beth Hawkins Bradley, RN, MN, CWON is the director of Clinical Operations at Cardinal Health. She has been certified in the specialty of Wound, Ostomy, Continence nursing since 1990.

The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, Kestrel Health Information, Inc., its affiliates, or subsidiary companies.