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Promoting successful wound healing

Key learning points

 - Wound causes and special considerations for these different types

- Wound assessment and dressings

- Encouraging effective healing at different stages 

The process of tissue repair or healing is extremely complex and unpredictable particularly in older patients suffering from multiple co-morbidities and with the effects of aging on the tissues. In all cases, healing will rely upon the controlled response to trauma and the intrinsic ability of the body to heal. Blanket treatments are unacceptable as every patient´s healing needs and each wound are unique which will present ever-changing challenges to the clinician. With the cost of chronic wounds estimated in the UK to be £2.6 billion per annum (2005-6 prices), approximately 200,000 patients at any one time having a chronic wound and the excessive amount and cost of nursing time involved, the pressure is on to ensure that wound management is as effective as possible.1 

Recognising and addressing the difference in individuals with wounds requires that we have the up-to-date knowledge and skills to manage wounds correctly. This paper will briefly explore common chronic wound types, their aetiology and, where relevant, evidence-based management. 

Wound types

In the main, intentionally created, acute surgical wounds and simple lacerations, in an otherwise healthy person, will heal without a problem. Acute wounds are expected to heal within an anticipated timeframe with no patient or environmental factors delaying healing.2 Minimal or no tissue loss allows clean, acute wounds to rapidly seal and heal through a complicated process that is not yet fully understood, especially in terms of why some patients heal efficiently and others suffer extended healing times or non-healing. 

The more commonly encountered and problematic wounds are those that become chronic or indeed start as chronic wounds which include leg ulcers, pressure ulcers, diabetic foot ulcers, dehisced wounds and any wound that is being left to heal by secondary intention. Such wounds can be identified as chronic from their first appearance, if the underlying aetiology is diagnosed, and the most appropriate treatment implemented. This is essential to developing a successful care plan for optimising the patient´s condition to achieve healing, where possible.

Wound assessment

To enable high quality and effective wound management the assessment must be accurate (properly reflect wound characteristics), current (as wound characteristics can change rapidly), comprehensive (to ensure nothing important is missed) and reliable (credible and objective). It should be sufficient to demonstrate rational and logical problem-solving and lead to optimal patient and wound and management decision-making.

After obtaining a full patient and wound history, the initial stage of wound assessment is to ascertain the phase of healing. The wound may be newly formed and still be showing characteristics of the inflammatory phase (redness, heat, pain and swelling),3 which may be confused with the signs of infection if the duration of the wound is not considered. The proliferative phase is characterised by the formation of fragile granulation tissue which is easily traumatised by inappropriate handling or dressings, as will the new epithelial tissue in the maturation or re-modelling phase. Knowledge of the phases of healing is vital to ensure that the principles of wound healing are followed.

The basic wound assessment parameters include the wound type, size, location, tissue type, exudate, patient symptoms such as pain, inflammation, odour, wound edges, and assessment of the surrounding skin for example, excoriation or maceration.4 No definitive, agreed published guidance on the management strategies for individual types of chronic wounds exists, despite the publication of numerous pressure ulcer and leg ulcer guidelines, a debridement systematic review and consensus statements. 

Modern wound care products and therapies have, as their foundation, the concept of moist wound healing since Winter's5 work demonstrated that epithelialisation proceeds twice as fast in a moist environment than under a scab, proving that a moist wound environment is conducive to optimal healing. Since this time, we have seen the design, development, promotion and effective use of dressings and therapies that provide the desired moist, warm, clean environment flourish. Additional benefits of such dressings include reduction in pain while in situ, on application and removal; improved healing times and efficient management of exudate.

Colour classification

A practical, colour classification used to describe the clinical appearance, that initially appears simple, has been suggested for assisting identification of the phase of healing and guiding wound assessment and intervention.6 Colour classifying wounds helps to assess which phase of healing they may be in and, together with various wound staging systems (eg. European Pressure Ulcer Advisory Panel classicfiation for pressure ulcers, or Skin Tear Audit Research [STAR] classification for skin tears), assist in the choice of dressings and therapies.

Types of wounds

Black necrotic (eschar)

 - The tissue in the wound is dead and presents as dry, leathery material originating from the destruction of cells and blood vessels which may completely cover the wound making assessment of the depth and extent impossible.

 - Aim of management: to rehydrate the tissue, stimulate autolysis and prevent infection.

Dressings: the most commonly used is the amorphous or hydrogel dressing together with a semi-permeable secondary dressing, which is designed to release moisture to soften and ´dissolve´ dead tissue. Alternatively, hydrocolloid dressings are also designed to create a warm, clean, moist wound environment in which autolysis will occur, and to protect the wound. Autolysis relies on the inherent ability of the body through its enzymes, immune system and moisture to liquefy and eliminate necrotic and sloughy tissue. It is painless and only necrotic tissue or slough is liquefied when appropriate dressings are used; however, it can take a long time and may cause maceration of the wound and wound edges. Alternatively, the wound may be debrided surgically by a suitable qualified clinician, if tolerated by the patient.   

Yellow, sloughy

The wound is covered or partially covered in soft, moist, dead tissue, mainly yellow in colour but may range from white through to dark grey or brown. It is composed of dead cells accumulated in exudate and should be removed to reduce the risk of infection. The exudate levels must be accurately assessed before choosing the most suitable product.

 - Aim of management: to de-slough or debride, prevent infection.

 - Dressings: after determining the exudate levels, hydrogel or hydrocolloid dressings to encourage autolysis should be used. The wound must be monitored for signs of infection and managed with honey (eg. Activon) or silver-containing (eg. Sorbsan Silver) dressings, and a decision made as to whether systemic antibiotics are required if there is a host response to the wound infection.

Alternative methods may include larval therapy (biological debridement), in which sterilised maggots (available on prescription) work quickly and selectively to digest necrotic material by secreting bactericidal enzymes. Larval therapy has been demonstrated to be effective against methicillin-resistant Staphylococcus aureus and beta haemolytic streptococcus. Although larval therapy has been widely practiced throughout the United Kingdom for almost 20 years it does make many feel squeamish. 

Debrisoft, as endorsed by the National Institute for Health and Care Excellence,7 is a more recent innovation. It is a pad made of soft, polyester fibres secured and knitted together and cut at a special angle, length and thickness to effectively cleanse/debride skin and the wound bed. The product is quick and simple to use and is effective on acute wounds such as gravel rash and for mechanically removing slough from chronic wounds prior to assessment. The European Wound Management Association have published useful guidance on debridement.8

Green infected 

This indicates a confirmed infection with host response, classic signs of inflammation plus the extended criteria of tracking, bridging, excess exudate, etc.9

 - Aim of management: control infection and achieve healing.

 - Dressings: anti-microbials, silver-containing or honey dressings, topical negative pressure (TNP) therapy, larval therapy; antibiotics if clinically indicated. 

Red granulating

Granulation tissue consists of fine, tiny, fragile capillaries growing in an extracellular matrix.

 - Aim of management: protection and support for healing.

 - Dressings: assessment of the wound depth, extent and exudate level will guide the choice of dressings and all must minimise the risk of trauma to the wound, eg. non-adherent dressings for flat wounds, foam dressings, cavity fillers, fibrous/alginate dressings, absorbent or non-absorbent depending on exudate level.10 TNP therapy can be cost-effective, very effective and convenient, and is well accepted by patients and clinicians despite limited scientific proof of its usefulness. Many newer variations on the original foam dressing and heavy pump have been introduced for example, an irrigation facility and specialised abdominal dressings. A recent mini-review highlights some of the infrequently encountered complications of TNP.11

Pink epithelialising 

Re-epithelialisation occurs with the migration of cells from the periphery of the wound and exudate levels are very low. The 

new skin is fragile and the same rules apply as for managing granulation wounds. A cover of semi-permeable film or thin hydrocolloid is recommended and left in place until re-epithelialisation is complete.

Anomalies

Few wounds will fall into a single colour classification; many will be a mixture of several colours at the same time. The clinician must be knowledgeable about wound aetiology, healing and dressings, and therapies to decide the aims of treatment and priorities at each wound assessment/dressing change.   

Conclusion

Clinicians have a professional responsibility to avail themselves of the many reliable up to date  sources of information about wounds and the range of management options by accessing material published by national and international bodies such as the National Institute for Health and Care Excellence (NICE), European Wound Management Association (EWMA), European Pressure Ulcer Advisory Panel (EPUAP), Tissue Viability Society (TVS), Wound Care Alliance (WCA) and the World Union of Wound Healing Societies (WUWHS).

National guidance, position documents, anecdotal reports and personal experience are all useful guides to the development of good practice in wound care and produce valuable guidance. Wound care companies are also excellent sources of clinical data and information about individual dressings and therapies.

References

1. Posnett J, Franks P. The costs of skin breakdown and ulceration in the UK. In: The Smith & Nephew Foundation. Skin Breakdown. The Silent Epidemic. Hull: Smith & Nephew Foundation; 2007.

2. Benbow M. Modern wound therapies. Journal of Community Nursing 2007;22(2):20-8.

3. Hart J. Inflammation 2: its role in the healing of chronic wounds Journal of Wound Care 2002;11(7):245-249.

4. Mahoney K. Understanding the basics of wound care in the community setting. Journal of Community Nursing 2014;28(3):66-75.

5. Winter G. Formation of the scab and the rate of epithelisation of superficial wounds in the skin of the young domestic pig. Nature 1962;193:293-4.

6. Cuzzell J. Wound healing: translating theory into clinical practice. Dermatology Nursing / Dermatology Nurses' Association 1995;7(2):

127-131.

7. National Institute for Health and Care Excellence. The Debrisoft monofilament debridement pad for use in acute or chronic wounds. London: NICE; 2014. Available at: guidance.nice.org.uk/mtg17.

8. European Wound Management Association. 2013. EWMA Document: Debridement.An updated overview and clarification of the principle role of debridement. London: MEP Ltd

9. European Wound Management Association. Position Document: Identifying criteria for wound infection. London: MEP Ltd, 2005.

10. Wounds UK. Quick guide to exudate management. 2013. 

11. Zonghuan L, Aixi Y. Complications of negative pressure wound therapy: A mini review. Wound Repair and Regeneration 2014;22(4):457-61.