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©2017 National Pressure Ulcer Advisory Panel | www.npuap.org

What’s in that wound bed? Slough, Eschar, or Biofilm?

Linda J. Cowan, PhD, ARNP, FNP-BC, CWS

Disclosures

• Employed as a Research Health Scientist, North

Florida/South Georgia Veterans Health System,

Gainesville, FL.

• Research funding received from:

– VA

– Biomonde

– Healthpoint

– Smith & Nephew

– Hollister

– Medline

• This material is the result of work supported with

resources and the use of facilities at the VA.

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Disclaimers

• Speaker does not endorse any one

particular company’s products, is not

employed by industry, has no financial

interest in the listed commercial

companies.

• Contents of this presentation do not

represent the views of the U.S.

Department of Veterans Affairs or the

United States Government

Participants will describe:

• Key characteristics of chronic non-

healing wounds

• Impediments to wound healing

• Characteristics of slough, eschar, and

biofilm in open wounds

• Evidence-based approaches to address

or remove slough, eschar, and biofilm

from open wounds

• Potential antibiofilm treatment strategies

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Chronic Wounds vs. Acute Wounds

• All chronic wounds begin as acute

wounds

• Common chronic wounds

– Venous ulcers of the lower extremities

– Diabetic foot ulcers

– Pressure ulcers

– Complex trauma and surgical wounds

Key characteristics of chronic wounds

• Imbalanced at microcellular level

• Stuck in inflammatory phase1-4

– High MMPs / Low TIMPs (inverse correlation)

– High inflammatory cytokines

– Low growth factors

– Fibroblast inhibition5

• Does not follow expected pathway to

healing (less than 50% improvement in 4

weeks)6

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Percent Wound healing in 4 weeks

http://care.diabetesjournals.org/content/diacare/26/6/18

79/F1.large.jpg?width=800&height=600&carousel=1

58% of pts

who had >50%

reduction in

wound size at

4 weeks,

healed at 12

weeks6

Only 9% of pts

with <50%

reduction in

wound size at

4 weeks,

healed at 12

weeks

Internal Impediments to wound healing

• Physiological can be changed:

– Nutrition

– Smoking/nicotine

– Blood sugar control

– Medications

– Necrotic Tissue

• Physiological cannot be changed:

– Advanced age

– Certain comorbid conditions

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External impediments to wound healing

• Can be changed:

– Repetitive trauma - due to self or due to

caregiver/clinicians (failure to of-load;

inappropriate shoes/mobility devices; wet-to-

dry dressings)

– Exposure – toxic chemicals, environmental

hygiene, temperature

– Physical barriers – rolled wound edges, non-

viable tissue (slough, fibrin, eschar)

– Invasion – virulent pathogens (biofilm)

T-I-M-E-(s) Principle for WBP1,8,9

• T - Address non-viable tissue in wound

• I - Address infection

• M – Manage moisture

• E – Address wound edges

• S – Address surround periwound skin

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Documenting wound assessments

• Location

• Suspected etiology, contributing factors

• Size (W X L X D in cm)

• Undermining, tunneling (clock method)

• Exudate (color, amount, odor)

• Wound bed tissue (color, amount viable)

• Wound edges and surrounding tissue

• Last treatments used, compliance,

wound response, patient/CG education

Describing wound tissue

• Color of wound bed (in percentages)

• Viable (living tissue with good perfusion)

• Non-viable (not living)

• Boggy (wet spongy consistency)

• Fluctuant (moving in waves, movable &

compressible, variable/unstable)

• Friable (bleeds easily with light touch)

• Hypergranulating (overgrowing baseline)

• Pale (anemic looking)

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Characteristics of slough in wounds

• What it is

• What it is not

• Slough vs. Fibrin

Slough

• Best ways to remove

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Characteristics of eschar in wounds

• What it is

• What it is not

• When not to remove

Eschar

• When to remove

• Best ways to remove

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Characteristics of biofilm in open wounds

• Unable to see it with naked eye

• Polymicrobial

– Aerobic + non-aerobic bacteria

– gram pos + gram neg

– Fungus + virus

• Hydrophilic polymeric protective coating

• Quorum sensing

• Attached 2mm below wound bed surface

• Grows back in 48 hours

Scott Dowd, et al. (2008). BioMed Central Microbiology, 8(43). Courtesy of G. Schultz.

Distribution of Aerotolerance of Bacterial

Populations in Chronic Wounds

Aerobes

Facultative

Anaerobes

Strict

Anaerobes

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Prevalence of biofilm

More than • 60% of all chronic wounds

with biofilm

More likely more prevalent than we think• 7

Malone et al., 2017.

Problems of biofilm

• Impairs wound healing

• Host often lacking common signs and

symptoms of infection

• Difficult to detect, identify, eradicate

• Normal presumptive antibiotic treatment

may actually encourage biofilm growth

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Biofilm

• When to remove

• Best ways to remove

Potential antibiofilm strategies

• Prevention

• Debridement

• Topical products

• Systemic products

• Combined approaches

– “one-two” punch: removal and preventive

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Evidence for debridement methods

• Autolytic (exudate/MMPs)

– Pros/Cons

• Enzymatic (collagenase)

• Mechanical (debriding gauze, wet-to-dry)

• Sharp

– Scalpel, scissors, curette

• Ultrasonic (low and high frequency)

– With and without forced water

• Larval/biological

Evidence for Larval Debridement

Mudge• , E., Price, P., Neal, W., & Harding, K. G. (2014). A randomized

controlled trial of larval therapy for the debridement of leg ulcers: Results

of a multicenter, randomized, controlled, open, observer blind, parallel

group study. Wound Repair and Regeneration, 22, 1, 43-51.

Bohova• , Jana, Majtan, Juraj, Majtan, Viktor, & Takac, Peter. (2014).

Selective Antibiofilm Effects of Lucilia sericata Larvae Secretions /

Excretions against Wound Pathogens. Hindawi Publishing Corporation.

• Poppel, A. K., Vogel, H., Wiesner, J., & Vilcinskas, A. (2015).

Antimicrobial peptides expressed in medicinal maggots of the blow fly

Lucilia sericata show combinatorial activity against bacteria.

Antimicrobial Agents and Chemotherapy, 59(5), 2508-14.

Cazander• , G., Pritchard, D. I., Nigam, Y., Jung, W., & Nibbering, P. H.

(2013). Multiple actions of Lucilia sericata larvae in hard-to-heal wounds:

Larval secretions contain molecules that accelerate wound healing,

reduce chronic inflammation and inhibit bacterial infection. Bioessays,

35(12), 1083-1092.

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Questions?

• Contact information:

– linda.cowan@va.gov

– ebpdoc@gmail.com

References

1. Schultz, G. S., Sibbald, R. G., Falanga, V., Ayello, E. A., Dowsett, C.,

Harding, K., Romanelli, M., ... Vanscheidt, W. (2003). Wound bed

preparation: a systematic approach to wound management. Wound Repair

and Regeneration: Official Publication of the Wound Healing Society [and]

the European Tissue Repair Society, 11, 1-28.

2. Trengove, N.J., Stacey, M.C., Macaulley, S., Bennett, N., Gibson, J.,

Burslem, F., Murphy, G., Schultz, G. (1999). Analysis of the acute and

chronic wound environments: the role of proteases and their inhibitors.

Wound Repair and Regeneration, 7, 442-452.

3. Demidova-Rice, T., Hamblin, M.R., Herman, I.M. (2012). Acute and Impaired

Wound Healing: Pathophysiology and Current Methods for Drug Delivery,

Part 1: Normal and Chronic Wounds: Biology, Causes, and Approaches to

Care. Adv Skin Wound Care, 25(7), 304–314.

4. Schultz, G. (2014). Molecular and cellular regulation of wound healing: What

goes wrong when wounds fail to heal or heal too much?. London: Henry

Stewart Talks. http://hstalks.com/lib.php?t=HST186.3834&c=252.

5. Harding, K. G., Moore, K., & Phillips, T. J. (2005). Wound chronicity and

fibroblast senescence - implications for treatment. International Wound

Journal, 2(4), 364-368.

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References

Sheehan6. , P., Jones, P., Caselli, A., Giurini, J.M., Veves, A. (2003). Percent

Change in Wound Area of Diabetic Foot Ulcers Over a 4-Week Period Is a

Robust Predictor of Complete Healing in a 12-Week Prospective Trial.

Diabetes Care, 26(6), 1879-1882.

Malone7. , M., Barjnsholt, T., McBain, A.J., James, G.A., Stoodley, P.,

Leaper, D., Tachi, M., Shultz, G., Swanson, T., Wolcott, R.D. (2017). The

prevalence of biofilms in chronic wounds: a systematic review and meta-

analysis of published data. Journal of Wound Care, 25(12), 1-5.

Schultz8. , G. S., Barillo, D. J., Mozingo, D. W., & Chin, G. A. (April 01, 2004).

Wound bed preparation and a brief history of TIME. International Wound

Journal, 1(1), 19-32.

Leaper9. , D. J., Schultz, G., Carville, K., Fletcher, J., Swanson, T., & Drake,

R. (January 01, 2012). Extending the TIME concept: what have we learned

in the past 10 years? International Wound Journal, 9, 1-19.

Granick10. , M., Boykin, J., Gamelli, R., Schultz, G., & Tenenhaus, M.

(January 01, 2006). Toward a common language: surgical wound bed

preparation and debridement. Wound Repair and Regeneration, 14.

References

11. Cowan, L., Phillips, P., Stechmiller, J., Yang, Q., Wolcott, R. & Schultz, G.

(2013). Antibiofilm Strategies and Antiseptics (Chapter 4) in Antiseptics in

surgery: Scientific basis, indications for use, evidence based

recommendations, vacuum instillation therapy; Willy, C., & Alt, V. (editors),

33 tables. Berlin: Lindqvist Book Publ.

12. Cowan, L., Phillips, P., Liesenfeld, B., Mikhaylova, A., Moore, D., Stechmiller,

J., & Schultz, G. (June 01, 2011). Caution: When Combining Topical Wound

Treatments, More Is Not Always Better. Wound Practice & Research: Journal

of the Australian Wound Management Association, 19(2), 60-64.