What You Should Know About Using Silver Products In Wound Care
In particular, the silver cation Ag+ is a “very potent antimicrobial agent because it can attack and damage bacterial cells at multiple sites,” notes Dr. Ovington. She explains that it attaches to specific chemical groups (thiol groups containing sulfur and hydrogen) found on a wide variety of proteins that play structural and functional roles in the bacterial cell.
Once Ag+ attaches to these sites, Dr. Ovington says the cation causes structural and functional changes in the cell. For example, she notes that when Ag+ binds to proteins in the cell membrane, the cell wall can rupture and leak, resulting in the death of the bacterial cell.
Dr. Ovington emphasizes that researchers have shown the silver ions are bactericidal against nearly 150 strains of bacteria as well as common fungi.
A: Dr. Ennis primarily uses impregnated alginates and foams. Dr. Cantor praises the foam-backed, ionic silver product Algidex Ag for its “excellent absorption” and notes that it is particularly effective on heel wounds due to the foam cushion and silver delivery.
Dr. Cantor cites Acticoat (Smith & Nephew) as being “instrumental” in facilitating the rise of silver-impregnated dressings in the late 1990s. Acticoat facilitates healing by depositing nanocrystals on the wound surface, but Dr. Cantor cautions that one may see temporary staining of the skin, which can interfere with assessing the wound bed, especially when clinicians are evaluating patients who have darker pigmentation.
Employing silver alginates like Acticoat and Silvercel (Johnson & Johnson), the silver hydrofiber Aquacel Ag (ConvaTec) or the silver foam Contreet F (Coloplast) can be helpful in managing highly exuding ulcers, according to Dr. Ovington.
Dr. Cantor concurs, emphasizing that the structural makeup of Aquacel Ag immobilizes both exudate and microrganisms within the structural makeup of the hydrofibers. He says the modality also reduces seepage and periwound maceration. In regard to Silvercel, Dr. Cantor says it provides “excellent absorption” for exuding wounds.
When it comes to low exuding wounds, Dr. Ovington says the silver hydrocolloid Contreet H (Coloplast) and the silver hydrogel Silvasorb (Medline) are useful in maintaining tissue hydration while controlling bacteria.
Q: Are there any contraindications for these products?
A: Dr. Ovington says most topical wound dressings are contraindicated for third-degree burns. Drs. Ennis and Weber suggest extra caution when considering silver products for patients who have a history of metal allergy. While silver allergies or hypersensitivities are rare, Dr. Weber notes they do affect a percentage of the population.
Dr. Ovington emphasizes that clinicians should use exercise caution when using silver products in the presence of enzymatic debriding agents. “Metal ions such as silver are known to inactivate enzymes and may negate the debriding effect,” explains Dr. Ovington.
The majority of the panelists cite the possibility of staining of the skin in and around the wound due to the use of silver in the tissues. While Dr. Ovington says this is “primarily a cosmetic problem,” she says it may indicate that very high amounts of silver are being released at the wound surface. This can potentially delay epithelialization, cautions Dr. Ovington.
Dr. Weber adds this discoloration and irritation is well documented but mainly occurs with silver nitrate. However, he notes some have observed absorption of silver, systemic distribution of silver and excretion of silver in urine among patients who have used topical silver products. When it comes to using silver nitrate and silver sulfadiazine (SSD), Dr. Weber adds there have been rare cases of leucopenia, bone marrow toxicity as well as renal and hepatic damage through silver deposition.