Nonadherent or low-adherence dressings
Various types of nonadherent or saline or hypochlorite (eusol)-soaked gauze dressings are often regarded as standard treatment for diabetic ulcers and have usually been used as the control arm in studies of dressings. These dressings are designed to be atraumatic and to provide a moist wound environment. These simple, relatively inexpensive dressings are not designed specifically for managing infection but can be safely used in conjunction with antibiotic treatments.
Hydrocolloid dressings are semipermeable to vapor, occlusive to wound exudate, and absorbent. They are usually presented as an absorbent layer on a film or foam. Examples of commercially available products include Duoderm , Granuflex , and Comfeel . They were found to be the second most popular choice of dressing for all diabetic foot ulcers. Despite their popularity, their use on infected wounds is controversial. Hydrocolloid materials are designed to be occlusive, trapping exudate within the dressing and hydrating the wound. This creates a hypoxic and moist environment that may also facilitate autolysis of necrotic material. Their use for highly exudative wounds can lead to maceration of the surrounding skin. Concerns persist regarding their use for infected wounds. Some evidence suggests that occlusive dressings may reduce the risk of infection developing in a wound by increasing infiltration of polymorphonuclear leucocytes . Most authorities, however, have expressed concern that hydrocolloids may increase the risk of infection developing within a wound . Hydrocolloid dressings are designed to be left on the wound for prolonged periods (⩾1 week); this is useful in managing clean ulcers, but not when regular wound inspection is required. Thus, these dressings are probably more useful in preventing, rather than treating, infection within a wound.
Hydrogels are similar to hydrocolloid dressings in that they are designed to facilitate autolysis of necrotic tissue, but they differ in that they donate moisture to extensively dry wounds. Examples include Aquaform and Intrasite Gel. Thus, they can lead to maceration when applied to wounds that are moderately to heavily exudating. Their use on a diabetic foot lesion should be as an adjunct to sharp debridement of necrotic eschar. Further, they should be applied cautiously on patients with limb ischemia, because dry gangrene could potentially rapidly progress to wet gangrene, with serious consequences. In vitro studies have shown that hydrogels will not support bacterial growth , although a reluctance to apply gels to infected wounds persists.
Foam-based dressings are another popular choice for diabetic foot ulcers. The dressings have a wide range of absorbency, provide thermal insulation, and are easily cut to shape. Examples include Allevyn and Cavicare. There have been few published data on their use in diabetic foot ulceration and none on their use in infection. However, their absorbency and comfort would theoretically make them a suitable choice. A new foam dressing (Avance) impregnated with bactericidal silver has recently been introduced.
A wide range of different alginate, or seaweed, products are currently available. They are highly absorbent, pack into cavity wounds, provide hemostasis, and are atraumatic at dressing change (but may require wetting). Examples include Kaltostat and Sorbsan. It is important to ensure that all dressing is removed from a cavity wound, because retained dressing may be a source for further infection. The dressings may have some bacteriostatic properties. Calcium alginate dressing inhibited growth of Staphylococcus aureus in vitro, with no increase in growth of Pseudomonas, Streptococcus pyogenes, or Bacteroides fragilis . Alginates should be safe to use on infected foot ulcers, provided there are regular and thorough dressing changes.
Antiseptics, such as iodine-based preparations, are commonly used on wounds, although there is no evidence to support a beneficial effect. Typically they are applied to locally infected wounds, usually in combination with systemic antibiotics. Iodine comes in 2 main preparations: cadexomer-iodine and povidone-iodine. Iodine is bactericidal in vitro, with maximal activity at 0.1%–1%. Povidone-iodine has long been used as a skin antiseptic, but its antimicrobial effect on wounds is debatable . Furthermore, some data have shown iodine solutions to be toxic to fibroblasts and keratinocytes . A randomized controlled trial of cadexomer-iodine versus saline-soaked gauze on clean foot ulcers showed no significant difference in healing between the groups . Certain iodine dressings are highly absorbent and therefore useful in preventing skin excoriation in moderately exudating ulcers. In our own clinical practice, cadexomer-iodine pastes are used for cavity wounds and povidone-iodine gauze for superficial ulcers. Despite the lack of evidence, many, including ourselves, consider iodine preparations to be appropriate dressings for infected diabetic foot ulcers.
The use of silver as a topical antimicrobial for acute and chronic wounds is well established. It has been traditionally delivered as silver nitrate (on sticks or roll-ons) or as silver sulfadiazine (e.g., Flamazine ointment). Silver nitrate has cytotoxic effects on host cells, a property often exploited in the treatment of hypergranulating tissue, but its application can be uncomfortable. Silver sulfadiazine, which has the antimicrobial actions of both silver and sulfadiazine, is used on burns and chronic wounds and is generally well tolerated.
The antimicrobial effects of silver are complex, including direct inhibition of bacterial cell respiration, inactivation of intracellular enzymes, and alterations to the cell membrane . Silver-coated dressings that use elemental silver may be more efficacious at killing bacteria than is silver sulfadiazine or silver nitrate . New silver-impregnated dressings may be suitable for use for infected diabetic foot ulcers. Examples include Acticoat and Actisorb 220. There have been no randomized controlled clinical trials of these dressings in diabetic foot ulceration. However, reports of accelerated wound reepithelialization and beneficial antibacterial action in the treatment of burns are encouraging.
Vinegar soaked dressings
It’s one of the most economical and readily available choice of dressing. Vinegar soaked dressing is a type of non-adherent dressing for maintenance of a freshly debrided wound as it helps keep the wound fresh. Its acidic nature autolyse the dead n unwanted pus cells n maintains wound asepsis.