Normal wound healing, and the enemies!

Esther White

Tissue Viability Nurse

A wound - definition

• A wound may be defined as the interruption of continuity in a tissue, usually following trauma. Skin is predominantly affected although any tissue, whether nerve, bone or organ, may be wounded.

How do wounds heal?

• Normal healing process is a well orchestrated, complex and interlinked series of four well recognised overlapping phases

Understanding normal healing

Four phases of wound healing:

1. Vascular response (or coagulation)

2. Inflammation

3. Proliferation

4. Maturation

The normal process can be interrupted at any stage and is

vulnerable to a variety of intrinsic and extrinsic factors

Vascular response

• Trauma

• Bleeding

• Fibrin mesh temporarily closes wound and dries to form a scab

• Blood and serous fluid help to cleanse the wound surface

Inflammatory phase • Release of inflammatory modulators

• Vasodilation, heat and erythema

• Increase in exudate rich in MMPs

• Neutrophils are 1st line defence against infection (but short life span)

• Macrophages & lymphocytes clean wound bed so that cells go to proliferation phase

Proliferation

• Granulation tissue produced through collagen production (scaffolding)

• Extra cellular matrix is also built

• Scar tissue starts to be restored to structure and function

• Epithelial cells & fibroblasts from uninjured tissue & stem cells circulate towards the wound

• The fibroblasts send out Spiderman like web and pull edges inwards

Maturation

• Collagen fibres are re-organised and constantly new collagen is being synthesised

• Scar tissue is gradually remodelled & eventually is comparable normal tissue

• Full repair can take 12-18 months but only 80% tensile strength is ever regained

As a rule....

• Most wounds follow this 4 stage process

• BUT...unfortunately most of the wounds that we see are chronic and often hard to heal

Put your Detective Hat and pipe on.....we need to see what is causing the break in this clever process in order to know how to treat it!

Some science .........

MMP’s Matrix metalloproteinases

• Important part in wound healing

• Produced by inflammatory and wound cells – essential in the migration of cells

• Can remove denatured cells

• HOWEVER – they can start to degrade healthy tissue and functional parts of the matrix

• Too much present = degrading proteins, leading to delayed healing

How do we as nurses know?

Wounds are failing to progress Wounds appear ‘inflammatory’ Cycles of local wound bed infection Less than 40% wound area reduction in 4 – 6 weeks is a

significant indicator

A protease testing kit has been developed (still awaiting more info so don’t get excited!)

Vicious circle of delayed wound healing

Breaking out of the circle to encourage healing

But wound care can be challenging…

What are the challenges?

Skin care or wound care?

Dealing with complex underlying causes

Toe bandaging? You ARE joking??

Improve peri - wound skin

Skin problems?

Treat the cause – unmanaged exudate will increase bacterial burden and therefore the

inflammatory response

Debride or not debride?

DVT, Cellulitis or oedema?

How realistic can you be?

What are the underlying problems?

Identify problems for healing

Villains of wound healing...

• Pain

• Compromised blood supply

• Increased or decreased moisture

• Devitalised tissue – slough, necrosis

• Infection – local or systemic

• Oedema

• Co-morbidites

Specific factors – think outside the box!

• Intrinsic

• Extrinsic

• Wound

specific

Patient related - Intrinsic

Co morbidities (Diabetes, PVD, Rh Arthritis, Renal disease, COPD)

Pain Ischaemia EoL status Immobility Mental health (including anxiety & depression) Malnutrition Anaemia Medication associated with co morbidities Underlying osteomyelitis

Patient related factors - Extrinsic

• Non concordance

• Social isolation

• Financial/ employment issues

• Environmental

• Nurse/ pt relationship

• Is a carer for others

• Cultural/ religious beliefs

• Previous experiences

• Lifestyle choices

Wound related factors Long wound duration Large wound (> 100cm²) Full thickness wound (Exposed tendon or bone) Underlying osteomyelitis Failure to progress by 40% at 6 weeks Presence of devitalised tissue Presence of local infection Presence of systemic infection High exudate levels Wounds over a moveable joint Wounds that are in close proximity to an ‘orifice’ (ie anus, stoma) Inflammatory/ excoriated or macerated peri wound skin Presence of oedema History of previous damage to same site Malignancy

In summary:

• Understand normal healing so you can recognise the abnormal

• Assess holistically to enable you to identify the risks for healing

• Recognise why a wound is ‘behaving’ in a certain way and be able to put a evidence based plan in place to manage the problem.

• Measure the effectiveness of your management plan taking appropriate action if outcomes aren't being met.