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Clinical Update TEN TOP TIPS Understanding and managing wound biofilm


“There is significant debate as to


whether clinicians can rely on clinical indicators to determine the


presence of biofilm in a wound.”


Figure 1. Examples of Pseudomonas aeruginosa visualised using microscopy. [A] A scanning electron microscope shows the outlines of bacilli (red arrow) embedded in the exopolymeric matrix of a biofilm on the surface of the pig skin explant, and confocal laser scanning microscopy of P. aeruginosa in [B] planktonic form and [C] as part of a biofilm community.


[A]


associated with use of implants and prosthetics such as indwelling urinary catheters, heart valves, joint replacements and contact lenses. Risk factors include: immuno-compromise;


decreased perfusion; presence of foreign bodies; hyperglycaemia; white blood cell dysfunction; necrotic tissue; oedema; malnutrition; repeated trauma; high moisture levels. Malik et al[24]


also


suggest that the following may contribute to the development of biofilm formation: diabetes, duration of ulcer >1 month, size of wound (>4 cm2


), male sex, and previous antibiotic use. 4 [B] [C]


WOUND CLEANSING: THE FIRST STEP IN REMOVING NONVIABLE


DEBRIS FROM THE WOUND Rodeheaver and Ratliff[25]


define wound Images courtesy of Professor Gregory Schultz.


There is significant debate as to whether clinicians can rely on clinical indicators to determine the presence of biofilm in a wound.[10] Table 1 summarises the key factors that may


indicate the presence of biofilm. Broadly, the clinical indicators that should raise suspicion of biofilm include: • Antibiotic failure • Infection of >30 days’ duration • Friable granulation tissue • A gelatinous material easily removed from wound surface that quickly rebuilds.


3


RISK FACTORS FOR BIOFILM FORMATION: BE ABLE TO


RECOGNISE PATIENTS AND WOUNDS THAT ARE AT RISK


Although there is limited information regarding specific risk factors for biofilm, it is felt that many of the same factors that delay wound healing also predispose to biofilm formation.[23] We now understand that many medical


conditions are the result of biofilm formation, cystic fibrosis, periodontitis, endocarditis, kidney stones, tonsillitis, osteomyelitis, and persistent otitis media, to name a few. Biofilms are also


22


cleansing as the “removal of surface contaminants, bacteria and remnants of previous dressings from the wound surface and its surrounding skin”. This definition best reflects the importance of removing all dressing product, wound debris and care of the periwound. Benefits attributed to wound cleansing are well known, but the issue appears to be when, how and, with what. An international consensus asserts that cleansing an infected chronic wound at each dressing change is warranted.[26]


Other


indicators for cleansing a wound are obvious contamination with dirt, debris, foreign matter, excess exudate, slough and nonviable tissue. As with any wound, a holistic assessment


is completed and the wound and patient requirements are determined. Optimally solutions should be at body temperature to avoid cooling of the wound and risk of slowing mitotic activity.[27] Methods employed for wound cleansing


may vary. Therapeutic irrigation with a force of 4–15 psi has been demonstrated as effective and safe.[28]


Whatever solution is chosen to clean the


wound, it should be: nontoxic; hypoallergenic; readily available; cost-effective; easy to use. Wound cleansing solutions commonly used


in wound management include: sterile normal saline, sterile water, potable tap water, and liquid antiseptics. A Cochrane review in 2008[29] concluded that there was some evidence that using potable tap water to clean a wound may reduce planktonic bacteria; other studies suggest that normal saline and tap water are ineffective for biofilm management.[20] When wound infection is suspected then a solution with a surfactant, antiseptic, or antimicrobial agent is recommended. Further


Wounds International Vol 5 | Issue 2 | ©Wounds International 2014 | www.woundsinternational.com


Ten Top Tips


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