Advanced dressings can also be used on a preventative basis when a superficial pressure ulcer in its early stages is detected. The market for moist dressings includes: foams, transparent films, hydrocolloids, alginates, hydrogels, hydrofibers and superabsorbent dressings. Generally, the least to most absorptive dressings are: hydrogels, transparent films, hydrocolloids, alginate foams and superabsorbent dressings. These dressings come in various formats. Dressings can have an adhesive tape at the surrounding edges (called an “island dressing”) or can be applied with the addition of a secondary dressing to secure the moist dressing in place. They can also come in sheets, rope or amorphous gel.
Foam dressings are one of the most absorbent products within the moist wound care market. They are made from polyurethane foam and come in the island dressing format or fixed with a secondary dressing. Foam is relatively inexpensive to manufacture and can easily be incorporated with other materials such as silver. High absorbency means that the dressing can absorb a high level of exudate and has to be changed less frequently. Foam dressings can be left on the wound for three to four days on average and for up to seven days depending on the level of exudate. This also decreases the amount of moisture on the wound, which reduces maceration. Foam dressings are best used during the inflammatory phase, following debridement when excess fluid and necrotic tissue are removed. If the wound is not heavily exuding, the foam dressing can desiccate the wound bed. Foam dressings also act as cushioning, giving the patient increased comfort and alleviating the pressure that can lead to pressure ulcers.
Transparent film dressings are a single thin layer of polyurethane and are ideal for shallow wounds. Their transparency allows the wound to be observed without having to disturb the dressing. These dressings are impermeable to fluid and bacteria, but are one of the least absorptive dressings. Therefore, they are ideal for providing mechanical protection to minimally exuding wounds.
Hydrocolloid dressings are made of hydrophilic particles, such as sodium carboxymethylcellulose, bonded to polyurethane foam or film matrix. As the dressing absorbs moisture, it forms a gel to create a moist wound bed. Hydrocolloids are mid-range along the spectrum of absorbent dressings, so some wound fluid is not absorbed and remains in the wound bed to allow for autolytic debridement. Hydrocolloid dressings are changed two to three times a week depending on the amount of exudate. Due to their mid-performing absorbency and semi-permeability to air and water vapor, there is concern that hydrocolloid dressings can cause maceration of the wound and its surrounding area. These dressings adhere to dry skin and moist surfaces, but do not adhere to the moist wound bed. If not applied correctly, leakage of wound exudate can occur.
Alginates are a primary dressing made of calcium or calcium sodium salts derived from the polysaccharides of brown seaweed. Alginates and hydrofiber dressings are the best dressings for deep, cavity wounds as they can be packed inside the wound. Alginates form a soft gel when they come in contact with wound exudate. Alginates are sold as non-woven pads or in a fibrous rope form. The physical form of the dressing/wound and the level of exudate determine whether a secondary dressing is required and the frequency of dressing changes. Alginate dressings can be used on infected, heavily exuding, and cavity wounds. They are easily removed and conform to the wound bed shape. If the wound is not heavily exuding, the alginate dressing can desiccate the wound bed.
Hydrofiber dressings, or hydrocolloid fibrous dressings, are made of spun sodium carboxymethylcellulose fibers and are sold in ribbon and sheet format. They are highly absorbent dressings as well. Hydrofibers are used on cavity and superficial wounds with medium to heavy exudate. Maceration of the skin around the wound is reduced as the fiber is designed to wick away moisture. If moistened before application, hydrofiber dressings can aid in autolytic debridement. Hydrofibers require a secondary dressing and, depending on the level of exudate, can be left on for up to seven days.
Hydrogel dressings are water or glycerin-based dressings and are the least absorptive of the moist dressings. They function to cool and donate fluid to a dry wound bed, thus promoting autolytic debridement. Hydrogels are sold as impregnated gauze, sheets and amorphous gel in a tube. The sheets or wafers are cross-linked hydrophilic polymers, while the amorphous gel lacks this cross linking. They are ideal for necrotic and painful wounds such as skin tears, ulcers and minor burns. They are often used in a later stage of wound healing when the wound starts to dry out. Hydrogels should not be used on heavily exuding wounds and the skin around the wound should be observed for maceration. Caution should be exercised with infected wounds, as hydrogels could cause bacterial proliferation. Hydrogels with an adhesive border must be changed up to three times a week, while those without an adhesive must be changed once a day.