Silver-containing dressings and the need for evidence.

The field of wound care has been inundated with "active" dressings--those that deliver biologically active substances to the wound site--and much attention has been given to those containing silver. Silver is a broad-spectrum agent: it is bactericidal to a large number of Gram-positive and Gram-negative microorganisms, many aerobes and anaerobes, and several antibiotic-resistant strains. More than 10 dressings containing pure silver are currently available; all claim to enhance wound healing through the antimicrobial activity of silver. But research findings on silver's antimicrobial efficacy are often inconclusive or contradictory. How, therefore, can clinicians decide which dressing is most appropriate for each patient? A grading system for reviewing the literature is presented.