A recent report in the Drugs and Therapeutics Bulletin argued that the routine use of silver dressings for wounds is not cost-effective. Professor Richard White of the University of Worcester and the professional association Wound Care Alliance UK argues that this medical devaluation of silver is potentially dangerous.
Silver-containing wound dressings are under close scrutiny after recent publications in scientific journals and the national press have cast doubt on their clinical value. It is apparent that the use of wound dressings containing the antimicrobial silver is being restricted across the UK. This is happening ostensibly because the clinical evidence for their use is weak. However, that may be just a smokescreen for cost-cutting.
The evidence in favour of silver dressings is, importantly, sufficient for two major regulatory bodies: the MHRA (following European Medical Device directives) and the FDA. There can be no reasonable doubt that in vitro, silver is a proven broad spectrum antimicrobial that is active against a wide range of pathogens, including resistant organisms such as MRSA and VRE. While the Cochrane Systematic Reviews claim there is insufficient evidence to support the use of these dressings, the most recent of these acknowledges 26 RCTs incorporating 2066 patients (Storm-Versloot et al 2010).
The VULCAN Trial publication (Michaels et al 2009) has been cited as a 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 highlighted (White et al 2009). The central flaw is the use of silver dressings for prolonged periods of time (up to 12 weeks) without clinical justification, contrary to current best practice.
The authors thus present the use of topical silver products in a manner that is inappropriate, but seek to draw serious conclusions from the outcomes observed. This has led to the mistaken belief that silver dressings performed in a similar manner to dressings that did not contain silver and were at a lower unit cost.
As with all antimicrobials, silver dressings must to be used in an appropriate and structured manner for short periods with clear clinical objectives in mind - which was not the case in the VULCAN study.
A Best Practice Statement in the use of Topical Antimicrobials/Antiseptics 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 re-assessment.
This is a responsible attempt by those active in the field of wound healing to address concerns that have been raised regarding the use of silver dressings. The panel are mindful of the potential catastrophe that could lie in wait for those vulnerable patients with infected wounds denied access to silver dressings.
Wound care products companies must now respond by making sure that their instructions for use are clear and in accord with best clinical practice. In particular, restrictions must be put on the duration of use. The use of products in neonates and paediatric cases must also be carefully considered and appropriate advice given.
To withdraw silver without adequate justification and/or without clinical advice on alternatives will compromise care, increasing morbidity and mortality. The latter has been established through audits showing that the arbitrary withdrawal of silver has led to increased incidence of septicaemia and death (Newton 2010).
Those responsible for wound formularies should be mindful of the potential human costs associated with decisions based on poor science, and should be held professionally accountable in the event of a documented increase in septicaemia based on the withdrawal of silver dressings.
Responsible clinicians will continue to use silver dressings in the fight against wound infection as part of a co-ordinated and comprehensive method of reducing infection rates in the UK. The risks associated with arbitrary restriction or removal of products should be borne in mind by all who have responsibility for the prevention and management of wound infection.
1. Storm-Versloot MN, Vos CG, Ubbink DT, Vermeulen H. Topical silver for
preventing wound infection. Cochrane Database Syst Rev. 2010 17;3:CD006478.
2. Michaels JA, Campbell B, King B, Palfreyman SJ, Shackley P, Stevenson M.
Randomized controlled trial and cost-effectiveness analysis of silver-donating
antimicrobial dressings for venous leg ulcers (VULCAN trial). Br J Surg. 2009
3. White R, Cutting K, Ousey K, Butcher M, Gray D, Flanagan M, Donnelly J,
McIntosh C, Kingsley A, Fletcher J, Chadwick P, Gethin G, Beldon P. Randomized
controlled trial and cost-effectiveness analysis of silver-donating antimicrobial
dressings for venous leg ulcers (VULCAN trial) (Br J Surg 2009; 96: 1147-1156).
Br J Surg. 2010 97(3):459-60; author reply 460.
4. Newton H (2010) Reducing MRSA bacteraemias associated with wounds, Wounds UK 6(1); 56-65.
Richard White is Professor of Tissue Viability at the University of Worcester, WR2 6AJ.