Contact layer dressings
Contact layer dressings are thin, non-adherent sheets placed on an open wound bed to protect tissue from direct contact with other agents or dressings applied to the wound. Because they are non-adherent, they often make dressing changes less painful. They conform to the shape of the wound and are porous to allow exudate to pass through. Most contact layers are perforated like a net ( almost like a mosquito net) and are often silicone or nylon. They come in different sizes or rolls. They can be impregnated with vaseline or antibacterial substances like silver, iodine, or bismuth.
Indications
Contact layer dressings are commonly used during the initial treatment of burns. These patients often have much pain during dressing changes. If we place a non-adherent contact layer on the burnt skin first and then cover this with, for example, moist gauze, it will make the dressing change significantly less painful. Vaseline-impregnated contact layers are often used here ( for instance, Jelonet) because they are cheaper. You may have experienced that vaseline impregnated contact layers sometimes adhere slightly, especially when lying on the wound for several days. In our opinion, vaseline-impregnated contact layers are not entirely non-adherent, but they still work adequately. On the other hand, silicone-based contact layers are even more gentle as they basically never adhere to the wound bed. They are, however, more expensive.
Other examples where contact layers can reduce the pain during dressing changes are, for example, wounds from breast cancer or skin damage from radiation treatment. Be aware that many modern dressings already have a non-adherent inner layer. Most modern polyurethane foam dressings have an inner layer made of perforated silicone so that a separate contact layer may not be necessary.
It is widespread to use contact layer dressing over split skin grafts for about a week to avoid the graft being pulled off the wound bed at the first dressing change.
Contact layer dressings are also used to protect tissue like exposed bone or tendon when using negative pressure therapy. If we place a negative pressure foam directly on the bone or tendon, we can irreversibly damage this type of tissue. When we have a contact layer between, this acts as a buffer and reduces the negative pressure impact there.
Sometimes we use contact layer dressings to keep something inside the wound. If you fill a wound with honey, for example, the honey may just run out of the wound within a few hours. If we place a contact layer on top of the honey, we can reduce the amount of honey running out. We use the same principle when filling a wound with platelet-rich plasma (PRP). In the latter case, we often fold a contact layer dressing to make it slightly less permeable to hold the PRP nicely in the wound cavity.
Figure 1 Contact layer dressings without additives. These are usually made of fine mesh polyethylene nets, and they are used to protect fragile granulation tissue from a secondary dressing. Suppose you are using cotton gauze as your secondary dressing, for example. In that case, it is usually a good idea to have a contact layer in the wound bed to prevent the gauze from damaging the granulation tissue during dressing changes. You can also cover these contact layers with ointments or other products of your choice. You can, for example, cover them with honey.
Figure 2 Contact layer dressings with vaseline ( Paraffin). The examples above have quite similar properties. They differ, however, concerning how thick the contact layer is and how much vaseline they contain. Some of these are available as rolls, which is very useful in burn care. Although contact layer dressings per definition are non-adherent dressing, they can sometimes adhere a bit nonetheless. Cuticerin ( upper right image) differs a bit from the others here in that it truly is non-adherent.
Figure 3 Contact layers with vaseline ( also known as paraffin gauze) work well in the initial burn treatment phase. After the burn is cleaned, the paraffin gauze is placed on the entire burn site( left image) and then covered with slightly moistened gauze (right image). As we mentioned earlier, most paraffin gauzes will adhere somewhat to the wound bed, especially when left in place for several days. Remove the dressings slowly. If there are areas where the contact layer adheres, you can try to moisten the area with saline. You can even drip some lidocaine on these areas to make the dressing change less painful.
Figure 4 Contact layers with antimicrobial properties. This is a very diverse product group, and they vary a lot as to what antimicrobial additives they have. Silver impregnated contact layers are widespread. They may differ a lot (a lot!) concerning the actual silver concentrations. Silverlon ( upper right) is one of the products with the highest silver concentrations- see table 1 for comparison below. In the middle row, there are some selected contact layers containing iodine. The green dressings in the bottom right corner are Sorbact contact layers. These apply a unique technology whereby microbes get trapped within the dressing fibers. At the end of the chapter, you will find a video explaining how Sorbact products work.
Table 1 As we can see from the table above, silver products vary significantly concerning the amount of silver they contain. Silverlon is one of the products on the market with the highest silver content. We know that many of the other products listed in the table also have good antimicrobial properties. From our own experiences, we have seen excellent results using Silverlon. Still, we have no studies of our own to show that there are significant differences concerning the antibacterial properties of these products. How much silver do you need to inhibit most bacteria in the wound? We will do a thorough literature search on this subject and keep you updated as soon as possible. Be aware that it is challenging to compare these products based on the silver content alone directly. The technologies concerning how the silver is applied on the carrier material differ significantly from product to product and affect how silver is released into the wound. copyright: Silverlon
Video 1 This video briefly explains the technology behind Sorbact dressings, which also applies to their contact layer dressings. copyright: Cutimed Sorbact
Video 2 An example of using a silver-coated contact layer dressing in combination with negative pressure treatment. copyright: Medela Healthcare