A Closer Look At Topical Therapies In Wound Care
Hydrogels are similar to hydrocolloids in composition and function. They are composed of polymers of hydrophilic chains. Available brand products include Tegagel (3M) and Curasol Hydrogel Saturated Dressing (Healthpoint Biotherapeutics). Accordingly, the benefits of hydrogels include absorbency, moisture support and aid in autolysis.21 Accordingly, hydrogels provide a similar environment to hydrocolloids but without the adhesive and occlusive properties. Like most of the limited research on topical wound care therapies, studies have failed to show that the use of hydrogels is superior when it comes to the treatment of diabetic wounds.22
Treating Exudative Wounds With Foams And Alginates
Exudate from open wounds can help provide a moist, good wound healing environment. However, in many situations, too much exudate overwhelms and complicates the wound healing process. Other times, the exudate is toxic and prevents proper wound healing by interfering or destroying healthy tissue.23 Exudate itself is mostly composed of water but also contains electrolytes, nutrients, inflammatory mediators, growth factors and many different types of cells involved in the wound healing phases as we previously described.24 Signs that the wound is producing either too much exudate or harmful exudate include periwound skin changes (maceration, denudation), odor, leakage or soiling of the bandage, and delayed healing. Types of topical wound care therapies that may be indicated for highly exudative DFUs include foams and alginates.
Physicians often use foams for these highly exudative wounds. Foams also provide thermal insulation and they can easily conform to the contours of irregular wounds to provide good protection in addition to providing good absorbency.15 Negative effects of foams include the inability to adhere and remove healthy tissue. They also have been reported to cause occasional dermatitis. Patients also describe the dressing as being bulky. A recent meta-analysis compared the use of foam dressings to hydrocolloids and found no significant difference.25
Alginate dressings derive from natural algae and seaweed. Restore Calcium Alginate (Hollister Wound Care) is one example of this type of dressing, which is ideal for highly exudative wounds. In addition to its absorptive properties, calcium alginate reportedly inhibits the growth of Staphylococcus aureus and limits growth of common microorganisms such as Pseudomonas aeruginosa and Streptococcus pyogenes.26 Alginate dressings can also be infused with a silver lining or other bacteriostatic agents, thereby treating wounds with higher bacterial loads. One can treat deep or irregular DFUs that are highly exudative with alginates as they also come in coiled or packable forms. Accordingly, alginate dressings are useful for a variety of different DFUs.
Can Silver And Iodine Preparations Have An Impact For Infected Wounds?
While we can often successfully treat colonized or contaminated wounds with topical antimicrobial therapies, local or deep infections may require additional oral or intravenous agents to maintain a good wound healing environment.13 The photo at right depicts a small plantar heel ulcer with a significant amount of surrounding edema and erythema. One should carefully examine this wound for the possibility of a deep infection. Common topical therapies for infected wounds include silver impregnated dressings and iodine preparations.
Silver impregnated dressings have direct antimicrobial effects. These effects include inducing direct inhibition of cellular respiration, inactivation of intracellular enzymes and alterations to the bacterial cell membrane.27 Other topical therapies include silver nitrate sticks, silver sulfadiazine ointment and other modalities that are impregnated with silver. The literature has shown elemental silver dressings to be more efficacious than silver nitrate sticks or silver ointment.28