Innovations in dressing technology for leg ulcer patients: Expert Commentary David Leaper, Visiting Professor, Cardiff University
22/02/12 | Leg ulcers, Service development and delivery | David Leaper
No accepted method currently exists for accurately predicting the risk of infection developing in a chronic wound. In order to address this gap, the Wounds At Risk (WAR) score was devised through a consensus group of European interdisciplinary hygienists/microbiologists, surgeons, dermatologists, wound healing and infection prevention clinicians.
The objective was to aid early decision making in the use of antimicrobials, specifically the topical antiseptic polyhexanide, to prevent progression to local or systemic infection.
The WAR score is flawed by not having been derived from logistic regression data analysis or Bayesian probability, for example, which may have given more reliable scores. However, such internationally sourced accurate data has never been collected and made available for statistical analysis - hence the decision by the group to devise a score based on the weighting of infection risk based on best current evidence and collective experience.
The WAR score considers the quantity and virulence of the pathogenic bioburden in a chronic wound together with the patient's immune competence. The microbiological continuum of contamination-colonisation-critical colonisation-local and systemic infection is also discussed, acknowledging that the diagnosis of infection is essentially clinical. The quantitative microbiological assessment of colonisation/infection is also considered and the difficulties of using a guide value of 105/g of tissue is highlighted. The drawbacks of microbiological sampling are, of course, legion and many microbiologists will not respond to requests to process a swab without consultation as they are aware that providing sensitivities to bacteria, which may be related to irrelevant transients or contaminants, often leads to inappropriate antibiotic therapy.
Wounds at risk are classified as being in two groups - those with endogenous factors (the patient's immune competence) and those with exogenous factors (the quantity and pathogenicity of organisms and their susceptibility to antimicrobials). Points are allocated in the WAR score in three categories of at-risk wounds:
- Class 1 (allocation of one point): based on the presence of metabolic diseases such as diabetes, cancer and its therapy, contamination and poor personal hygiene, long hospital stays, age, wound size and duration
- Class 2 (two points): severe immune defects, such as AIDS, and contaminated traumatic wounds
- Class 3 (three points): large burns, presence of foreign material, or extensive heavily contaminated wounds.
After all the risk factor points are added (and there may be more than one point scored in each class) the risk score is derived. When the WAR score is greater than 3, the use of topical antiseptics is indicated. However, no detailed advice is proffered on the use and timing of antibiotics.
In conclusion, the WAR score is a clinical guide for the early, and justified, use of topical antiseptics, specifically polyhexanide, in chronic wounds. There are no indications for debridement, nor any recognition of biofilm presence, which might require added intervention to optimise the value of topical antiseptics.
When diagnostics are available to detect the presence of biofilm or critical colonisation, WAR may become more helpful. However, there has been no validation of the use of the WAR score so far. The weightings have been derived from expert consensus opinion, rather than statistically derived data, and the score does needs a clinical study to prove its worth. However, WAR scores can already be used for classification and audit in wound care.
To read the Practice Development article 'Innovations in dressing technology for leg ulcer patients', click here.
- Dissemond J, Assadian O, Gerber V, Kingsley A, Kramer A, Leaper DJ, Mosti G, Piatkowski de Grzymala A, Riepe G, Risse A, Romanelli M, Strohal R, Traber J, Vasel-Biergans A, Wild T, Eberlein T. Classification of wounds at risk and their antimicrobial treatment with polyhexanide: a practice-oriented expert recommendation. Skin Pharm Physiol 2011; 24: 245–55.