Maintaining an airtight seal with VAC therapy may be difficult for highly exudating wounds and wounds that are irregular in size. Given these challenges, these authors present a novel technique to address this issue and reduce the risk of periwound maceration.
Despite the number of different modalities that exist for the treatment of acute and chronic wounds, VAC therapy (Vacuum Assisted Closure, KCI) has proven to be an effective and valuable tool for treating complex wounds.1-4 The VAC device utilizes the concept of negative pressure wound therapy (NPWT), in which controlled subatmospheric pressure causes mechanical stress to the tissue, which in turn causes the wound to close.5,6
Negative pressure wound therapy removes excess interstitial fluid, causes increased vascularity, decreased bacterial colonization and produces a response on the tissues around the wound through mechanical forces.7 All of these factors assist to increase the rate of healing with very little trauma to the patient.
The VAC therapy device utilizes a reticulated polyurethane foam dressing that one places in contact with the wound, maximizing the potential for tissue ingrowth.7 Additionally, the foam ensures equal distribution of sub-atmospheric pressure to every part of the wound that is in contact with the foam. An adhesive dressing secures the foam. This facilitates a semi-occlusive environment and helps to protect the periwound skin.
The physician then attaches the pump to the adhesive dressing, which is connected to a computerized therapy unit that delivers either intermittent or continuous suction. Settings are adaptable on the unit and the settings depend on the type and complexity of the wound. The fluid is drawn from the pump into a canister located on the VAC therapy unit. Warnings sound when the canister fills, preventing egress of the fluid into the patient. VAC therapy is a very convenient and valuable tool for healing wounds.
Overcoming The Challenge Of Difficult Wounds
Despite the practicality of VAC therapy, foot wounds can be a challenging and difficult area for placement of the VAC therapy device. It can be difficult to maintain an airtight seal for wounds that are in close proximity to other structures such as web spaces, highly exudating wounds or irregular shaped wounds.
Loss of this seal will cause extravasation of fluid, resulting in periwound maceration and an inability of the VAC therapy device to function properly. In a study by Armstrong and colleagues that discussed the outcomes of subatmospheric pressure dressing on diabetic foot wounds, 19.4 percent (six out of 31) of the patients in the study had a complication of periwound maceration.1
To help prevent this complication from occurring, one may create a durable seal with the VAC therapy device by using the Eakin® cohesive seal (TG Eakin Ltd.). The Eakin cohesive seal is a highly moldable, hydrocolloid product, which provides a waterproof and moisture absorbing skin barrier.8 It comes in two sizes (small and large) and helps to stop leakage and absorb moisture, preventing maceration and irritation around skin edges. The cohesive seal provides double-sided adhesion and is completely moldable. One may break, rejoin or layer the seal, and it is easy to remove.
A Step-By-Step Guide To Getting An Airtight Seal
The technique consists of rolling a piece of Eakin cohesive seal into a tube shape in order to line the wound edges. This also warms the seal to body temperature, making it easier to mold the seal. Once you have rolled the Eakin cohesive seal to the accurate size and shape, you can manually apply it to the wound edges until the entire wound is covered.
To ensure proper adhesion to the skin edges, make sure the area is dry and ensure that no other other skin preparations or creams are used. One can apply the Eakin cohesive seal over the VAC therapy adhesive drape, which the practitioner would place above the intact skin to frame the wound, or directly over the skin. This decision is based on the anatomical configuration and depth of the wound.
Additionally, the clinician can also apply the Eakin cohesive seal over any secondary dressing (such as Mepitel) used for a graft. At this time, it is better to place the VAC therapy adhesive drape over the Eakin cohesive seal instead of the skin due to the secondary dressing applied for the graft.
Proceed to apply the VAC therapy adhesive drape and make the sponge cut to fit the size and shape of the wound. It is important to roll the VAC therapy adhesive drape into the Eakins cohesive seal in order to create an airtight area and prevent a loss of fluid.
When you turn on the VAC therapy unit, negative pressure occurs and brings the Eakin cohesive seal securely against the tissue, maintaining a tight seal.
Physicians can perform this technique in any anatomical area, which is prone to periwound maceration. This includes wounds with little space or those around other structures. This technique is also effective for highly exudating wounds and irregular shaped wounds. It is an easy and inexpensive technique that can be performed by any clinician applying VAC therapy.
The consequences of an incomplete seal can delay wound healing and even bring damage to the periwound skin, creating an even larger wound. The aforementioned technique can prevent this from occurring and create an environment for more rapid wound closure.
Due to the seal’s many advantages and its effectiveness in stomas, its use with VAC therapy and difficult wounds make it a great choice to help diminish the complications of periwound maceration.
Dr. Hanft is the Director of Podiatric Medical Education at Baptist Health in South Florida. He is a Fellow of the American College of Foot and Ankle Surgeons.
Dr. Henao is a second-year resident at South Miami Hospital in South Miami.
1. Armstrong DG, Lavery LA, Abu-Rumman P, et al. Outcomes of subatmospheric pressure dressing therapy on wounds of the diabetic foot. Ostomy Wound Manage. 2002; 48(4):64-8. 2. Bovill E, Banwell PE, Teot L, et al. Topical negative pressure wound therapy: a review of its role and guidelines for its use in the management of acute wounds. Int Wound J. 2008; 5(4):511-29. Epub 2008 Sep 19. 3. Armstrong DG, Lavery LA. Negative pressure wound therapy after partial diabetic foot amputation: a multicentre, randomized controlled trial. Lancet. 2005; 366(9498):1704-10 4. Moisidis E, Heath T, Boorer C, et al. A prospective, blinded, randomized, controlled clinical trial of topical negative pressure use in skin grafting. Plast Reconstr Surg. 2004; 114(4):917-22. 5. Gupta S, Baharestani M, Baranoski S, et al. Guidelines for managing pressure ulcers with negative pressure wound therapy. Adv Skin Wound Care. 2004; 17 (Suppl 2):1-16. 6. Ilizarov GA. The tension-stress effect on the genesis and growth of tissues. Part II. The influence of the rate and frequency of distraction. Clin Orthop Relat Res. 1989; 239:263-85. 7. Argenta LC, Morykwas MJ. Vacuum-assisted closure: a new method for wound control and treatment: Clinical experience. Ann Plast Surg. 1997; 38(6):563-76 8. Eakin. Prevent leakage, prevent sore, irritated skin, remove the sting of stoma paste, extend pouch weartime with Eakin cohesive seal. Retrieved from http://www.eakin.co.uk/UPLOADS/DOCS/COHFLY1.pdf