Cath Lab Digest

  Clinicians in the UK and much of Europe have enjoyed ready access to the wide spectrum of available wound dressings for many years. However, economic pressures and lack of evidence have been cited as the reasons for recent restrictions on modern wound dressings — notably, those containing the antimicrobial silver — particularly in the UK. This has created frustration and confusion among clinicians and manufacturers, the former forced to vigorously defend clinical practices.

  What precipitated the change? Importantly, the available evidence supporting silver dressing use is sufficient for the major European Union regulatory bodies, including the Medicines and Healthcare Products Regulatory Agency (MHRA) in the UK (according to the European Medical Device directives 93/42/EEC), to bestow key “CE” marking approval. However, recent publications, including some systematic reviews,^1-4 have cast enough doubt on the quality of the available evidence to give purchasers the necessary rationale to restrict product availability. But because reviews can be contradictory,⁵ can we assume they are drawing accurate conclusions?

  There can be no reasonable doubt that silver, in vitro, is a proven broad-spectrum antimicrobial active against a wide range of pathogens, including resistant organisms such as methicillin-resistant Staphylococcus aureus (MRSA).^6-8 In vivo, numerous level 1 and level 2 studies and one meta-analysis demonstrate efficacy in burns.^9-11 Twenty studies in which silver dressings have been shown to be effective in leg ulcers or diabetic foot ulcers have been identified. Although Cochrane reviews claim evidence supporting the use of these dressings is insufficient, the most recent review² acknowledges 26 random controlled trials (RCTs) incorporating 2,066 patients with positive results. Thus, it can be argued that silver dressings have the requisite evidence to support their use.

  It is important that dressings containing silver be used exclusively in cases where clinical signs of infection are present or where a patient has been identified as at substantial risk of infection. The VULCAN Trial publication1 has been cited as the scientific rationale for removing silver dressings from wound formularies, based on a demonstrated lack of healing efficacy. However, serious methodological flaws in this study have been highlighted¹² — eg, silver dressings were used for prolonged periods of time (up to 12 weeks) without clinical justification, contrary to current best practice.^14-16 The authors seek to draw conclusions from the outcomes observed from inappropriate silver dressing use, fostering the misconception that silver-containing dressings performed in a similar manner to less expensive non-silver dressings. Given that the authors confirm in their report that the wounds treated with silver were “not infected,” this undermines the scientific value of the finding that silver dressings did not perform clinically.

  It is my contention that silver dressings must be used per manufacturer instructions — ie, in the presence of local infection or critical colonization — in order to be accurately assessed. Guidelines dictate that silver dressings must be used in an appropriate and structured manner for short periods, with clear clinical objectives in mind.^13-16 This was not the stated case in the VULCAN Study, nor is it as yet a universally accepted clinical practice. To address the latter issue, a Best Practice Statement in the use of Topical Antimicrobials/Antiseptics (www.wounds-uk.com/index.shtml) has been drafted by a panel of experts in the field and is currently out for consultation. It states that products such as silver wound dressings should be used in a timely and appropriate manner which is tied to accurate assessment and regular reassessment.