By Gabrielle Munro

Approximately 60-90% of chronic wounds have bioburden, which is associated with non-viable tissue in the wound bed and is often difficult to detect with the naked eye (Harries et al. 2016).

It is well evidenced that debridement is an effective method to remove the bioburden when managing chronic wounds. Debridement is defined by Wounds UK, 2013 as ‘the removal of dead, non-viable/devitalised tissue, infected or foreign material from the wound bed and surrounding tissue.’

In some chronic wounds bacteria may colonise in the wound bed without impairing the healing process. When wounds are in the inflammatory phase of healing he body releases inflammatory cells; neutrophils and macrophages, along with cytokines and proteases that produce matric metalloproteinases (MMPs) to assist with wound healing. The MMPs cut up the attachment between the bacterial biofilms and the wound bed assisting the wound to move through the phases of healing (Gibson et al. 2009). As the chronicity of the wound increases so does the bacterial load, and the body’s ability to self-debride becomes impaired and the wound becomes delayed in the inflammatory phase of healing (Powers et al. 2015).

More is being understood about the role of matric metalloproteinases in wound healing. At this stage we do not know the level or proteases needed for actual wound healing. Chronic wounds often have elevated MMPs. The balance is to have the right amount of MMPs to assist with debridement but not too many for too long as the MMPs then start to degrade the growth factors and receptors preventing angiogenesis and the contraction and remodelling of the ECM (Norman et al. 2016).

Despite the level of MMPs, nonviable tissue and bioburden delays healing. Debridement is considered gold standard to remove nonviable tissue and disturbs the cell cycle at a molecular level. It forces the chronic wound base into the inflammatory phase where healing can be resumed, with normal extracellular formation of granulation tissue, angiogenesis and epithelialization (Madhok et al. 2013; Wounds UK 2013; Harris 2009; Lebrun et al. 2010).

There are a number of techniques clinicians may choose to debride a wound in clinical practice. These methods include; autolytic, mechanical, enzymatic, biological, conservative sharp, surgical sharp, ultrasonic and hydrosurgical. In 2010, a systematic review by Edwards and Stapley conceded the best method to debride is not well evidenced due to low quality and methodological flaws of studies. More research needs to be done on debridement per se and the different methods of debridement to achieve wound healing.

The question is not only if debridement should occur, it is how, who and when debridement is appropriate. Then the decision is about what method or mode of debridement promotes the better, safer, more officious outcome for the client and is adaptable to multisite settings for implementation into everyday practice. Future research should evaluate multiple methods of debridement; in combination at different stages of the healing process with an outcome of total wound healing.


About the Author
Gabrielle Munro is a Nurse Practitioner Candidate, Goulburn Valley Health West Hume Region and Wound Consultant – Regional Wounds Victoria.

References
Edwards, J., and Stapley, S., 2010. Debridement of diabetic foot ulcers. Cochrane Database of Systematic Review. Issue 1. Art: CD003556. DOI: 10.1002/14651858.CD003556.pub2.
Gibson D, Cullen B, Legerstee R, Harding KG, Schultz G. 2009. MMPs Made Easy. Wounds International 2009; 1(1): Available from http:www.woundsinternational.com
Harris, R.J. 2009. The Nursing Practice of Conservative Sharp Wound Debridement: Promotion, education and proficiency. Wound Care Canada. 7(1):22-30.
Harries, R., Bosanquet, D., Harding, K., 2016. Wound bed preparation: TIME for an update. International Wound Journal. 13 (suppl. S3): 8-14.
Lebrun, E., Tomic-Canic, M., Kisner, R., 2010. The role of surgical debridement in healing diabetic foot ulcers. Wound Repair and Regeneration. 18(5): 433-138. DOI:10.1111/j.1524-475x2010.00619.x
Madhok, B., Vowden, K., &Vowden, P., 2013. New Techniques for wound debridement. International Wound Journal. 10:247-251.
Norman, G., Westby, M.J., Stubbs, N., Dumville, J.C., Cullum, N., 2016. A ‘test and treat’ strategy for elevated protease activity for healing in venous leg ulcers (Review). Cochran Database of Systematic Review. Issue 1. Art: CD011753. DOI: 10.1002/14651858.CD011753.pub.2.
Power, J., Higham. C., Broussaard, K., Phillips T., 2015. Wound healing and treating wounds – Chronic wound care and management. American academy of Dermatology. DOI.org/10.1016/j.jaad.2015.08.070
Wounds UK. 2013. Effective debridement in a changing NHS: a UK consensus. London: Wounds UK. Available from www.wounds-uk.com/pdf/content_10761.pdf. Assessed: Dec 2016.