Appropriate use of silver dressings in wounds: International consensus document

Topical antimicrobial dressings, including those that contain silver, are currently used to prevent or treat infection in a wide range of acute and chronic wounds. Although silver dressings are being used extensively, a published randomised controlled trial (RCT) (1) and two Cochrane reviews (2,3) concluded that there is insufficient evidence to show that silver dressings improve healing rates. The overall effect of these reports has been to cast doubt into the minds of healthcare purchasers, which has led to restrictions in the availability of silver dressings worldwide. There is growing concern amongst clinicians, who are involved in wound care, that arbitrary withdrawal of silver dressings could lead to their patients having increased morbidity and prolonged treatment time relating to uncontrolled wound bioburden. Because of this conflict of opinion, a group of experts from Europe, North America, the Fast East, South Africa and Australia met at the end of 2011 to provide internationally recognised guidance on the appropriate use of silver dressings, based on their experience in clinical practice and all the available published evidence. Additional international experts were also consulted to reflect practice across different parts of the world. Following this exercise, a consensus document was published that presents the mechanisms by which silver dressings work, the relationship of in vitro and in vivo evidence to clinical practice, and provides a rationale for cost-effective management (4). Many common misperceptions concerning the use of silver dressings were identified by the group. In contrast to the negative findings of the RCT and two meta-analyses (1–3), the experience of many clinicians and other metaanalyses have confirmed positive effects of silver dressings when they are used appropriately (5–7). This disparity is based on the use of complete healing as an endpoint, which is insisted upon by regulatory bodies such as the Food and Drug Administration of the USA in clinical trials of this nature. However, the use of silver dressings was never intended to directly promote wound healing but to control or reduce the bioburden of wounds, which if not addressed, does lead to delayed healing. The use of this more appropriate endpoint, control of bioburden, has been supported by many (8–12). Silver dressings are often perceived to be expensive, and although dressing unit costs are highly variable, their beneficial effects on overall cost of wound management and quality of life parameters are clear (13–17). Other misperceptions addressed in the consensus document are that silver dressings are unlikely to cause toxic local or systemic effects (although caution is suggested for use in large wounds, in children and in pregnancy/lactation), and that the risk of acquired antimicrobial resistance to silver (or to antibiotics) was negligible. Therefore, the appropriate use of all topical antiseptic dressings, such as those containing silver, is to reduce bioburden in wounds that are recalcitrant and often accompanied by progression of critical colonisation to infection. The antimicrobial effect of silver is mediated by the presence of the Ag+ ion which is disruptive to many aspects of micro-organism metabolism. This accounts for the broad spectrum of activity