Here is a step-by-step approach of the standard technique we use to apply VAC therapy at the Southern Arizona Veterans Affairs Medical Center.
1. Debride. As in every wound except for the most ischemic, debriding is essential. You should surgically and/or biologically (using larvae) debride the wound prior to applying the vacuum assisted closure device.
2. Wash. A thorough lavage/cleansing of the wound is important to reduce overall bacterial colonization and to further remove non-viable matter.
3. Cut and shape. The next step is to cut and shape the polyurethane (black) or polyvinyl alcohol (white) VAC sponges. We generally prefer the polyurethane sponge for many of our deeper wounds. Once you cut the sponge to the appropriate shape of the wound, it is a good idea to trace the outline of the sponge on paper or acetate. This serves two purposes. First, it allows us a way to record general wound size. Second, it serves as a template for the next dressing change and will therefore speed up the process.
4. Consider the periphery. We have found maceration appears in nearly 20 percent of the wounds in which the VAC is applied in our center. We have nearly eliminated this issue by using two techniques. First and most commonly, we will apply strips of a hydrofiber dressing (Aquacel, ConvaTec) around the periphery of the wound. The other, perhaps more widely used technique, is using a heavy ostomy-barrier paste. Either of these works. However, using the dressing makes secondary dressing changes and wound assessment a bit easier.
5. Apply the occlusive dressing. Lightly apply the dressing over the sponge and wound. Do this gently, trying to lay the adhesive dressing down like a blanket instead of a tent. This helps to reduce any free air spaces which can make a good seal difficult. This step (over irregular surfaces such as the foot) often requires multiple sheets of dressing. It often may require the complete covering of the foot. If this occurs, remember to reduce interdigital maceration by inserting lambswool or additional VAC sponge between the toes.
6. Insert the VAC line into the dressing and seal. Using a tenotomy scissor or scalpel, incise the occlusive dressing and the outer portions of the sponge to facilitate insertion of the VAC line. After insertion, you may apply another occlusive dressing around the portal. It often helps to pinch off the occlusive dressing at the VAC line’s entrance to the sponge, forming a sort of “omentum” of occlusive dressing. Under this omentum, you may consider using additional sponge to pad and protect the patient from pressure secondary to the tube.
7. Connect the lines and the reservoir. Snap the line to the reservoir and insert the reservoir into the unit until it clips into place.
8. Fire up the VAC and watch it suck. We generally will begin with a continuous setting at 125mm Hg, changing to intermittent after 24 to 48 hours. We have modified these settings slightly when using the VAC with other advanced wound healing modalities such as Dermagraft, Hyaff or Apligraf. If the pressure doesn’t rapidly ramp up to its appropriate setting, consider a poor seal to be the most likely culprit. Try manipulating the tube/dressing interface and if necessary, add additional occlusive dressing to complete the seal.
You can perform the dressing change in nine to 14 minutes and one to two people are required. The dressing change interval at our center was q 48-72 hours.