By Laurie Swezey RN, BSN, CWOCN, CWS, FACCWS
Antimicrobial dressings have enjoyed a surge of popularity in recent years- there are now many dressing products on the market containing antimicrobials. However, just because they are available doesn’t mean they are the best choice for your patient. Let’s look at the use/purpose of these dressings, some of the types available and under what conditions they should and should not be used.
How do antimicrobial dressings work?
It is now known that a moist wound environment is more conducive to healing than a dry one. The use of moisture-retentive dressings has become the norm, and these dressings have been shown to shorten healing time in various types of wounds. However, with added moisture in wounds there is also the creation of an environment that is conducive to the growth of bacteria.
Many wounds, particularly chronic long-standing wounds, have some degree of bioburden. In fact, this is almost expected, and clinicians pay little attention to this fact unless critical colonization, and a resultant slowing of the healing process, is noted; wounds that have a heavy bioburden along with signs and symptoms of infection are generally treated with some form of antimicrobial therapy. Antimicrobial dressings have become one weapon in the arsenal of antimicrobial therapy.
Antimicrobial dressings work by slowly releasing their active ingredient into the wound bed. In doing so, it is hoped that they will neutralize (kill) bacteria while having little effect on healthy cells.
Dressings containing silver
There are many dressings on the market that use silver. Silver has been incorporated into numerous dressing types, such as foam dressings, alginate dressings, gauzes and films. They may be used as a primary or secondary dressing. They can be very absorptive, depending on the type of dressing chosen. Silver has been shown to be able to kill numerous organisms; however, it may not be as highly effective in wounds containing multiple organisms or on biofilms.
Dressings containing silver are recommended for use on wounds that are critically colonized or infected. There is no evidence supporting their use in wounds that are not infected as they have not been shown to speed healing in these wounds. Silver dressings are more expensive than other dressings and vary greatly in the type and amount of silver released. Clinicians should carefully read directions for use and should keep in mind that saline will deactivate the silver in some cases. In addition, patients with a silver dressing should have their dressing removed before undergoing an MRI.
Iodine has been used for many years as an antimicrobial, but has only been introduced in dressing form in recent years. Cadexomer iodine is the form of iodine commonly used in dressings. It is indicated for use in chronic wounds which are thought to be, or known to be, infected. They should not be used on patients who have a hypersensitivity to iodine and should also not be used in patients with thyroid disease due i.e. thyroiditis, goiters as it is absorbed systemically.
Polyhexamethylene biguanide (PHMB) has shown to be an effective antimicrobial against a wide array of human pathogens, including HIV. It acts by disrupting cellular membranes in bacterial cell walls. It is indicated for use on partial- and full-thickness wounds, exudating or dry. This dressing has been shown to decrease wound pain. Some studies, however, have shown that, while PHMB is effective against the bacteria it comes in direct contact with, it is less effective at dispersing beyond the wound bed to the periwound.
Antimicrobials come in a wide variety of wound dressing types. They are not currently recommended for uninfected wounds and should only be used on wounds that are critically colonized or infected. They should be used for the shortest time required and should be discontinued if there is no improvement in wound appearance and healing within two weeks of beginning therapy. In addition, clinicians should keep in mind that indiscriminant use of antimicrobial dressings may lead to resistant bacteria.
OWM (2008) The Antimicrobial Benefits of Silver and the Relevance of Microlattice Technology http://www.o-wm.com/article/1348
Mulder, G., Cavorsi, J. & Lee, D. (2007) Wounds, 19(7):173-182 http://www.medscape.com/viewarticle/561512_4
OWM Topical Antimicrobials in the Control of Wound Bioburden—Part 2 http://www.o-wm.com/article/6022
Meyers, B (2008). Wound Management Principles and Practice. 2nd Edition. Upper Saddle River, New Jersey. Pg 139-140.
About The Author
Laurie Swezey RN, BSN, CWOCN, CWS, FACCWS is a Certified Wound Therapist and enterostomal therapist, founder and president of WoundEducators.com, and advocate of incorporating digital and computer technology into the field of wound care.
The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, Kestrel Health Information, Inc., its affiliates, or subsidiary companies.