WOUNDS AND WOUND CARE

All aspects of skin and soft tissue wounds, including acute surgical wounds, pressure ulcers and all forms of leg ulceration, are encompassed in the specialty of tissue viability. Wound care can be a challenging and complex area of practice, and nurses must take individual responsibility for updating their knowledge, skills and ongoing competence. If in doubt about the care of a wound, seek advice from a more experienced colleague or a tissue viability nurse specialist. Optimum care of a wound requires an understanding of wound healing, microbiology, asepsis, dressings, pain, pharmacology, psychosocial factors and ethics, and use of good communication skills. Diabetic foot wounds need referral to the podiatry team for assessment.

Wound healing principles

The healing process - the restoration of cellular structures and tissue layers – is a complex series of overlapping stages described as:

• Haemostasis, inflammation, proliferation, maturation, or
• Inflammation, reconstruction, epithelialisation, maturation.

Broadly, there are two categories of healing:

• Primary (by primary intention): generally minimal tissue loss, with wound edges held in apposition by clips, staples or sutures, eg surgical wounds. Healing will usually progress predictably.
• Secondary (by secondary intention): usually greater tissue loss, with wound edges further apart. Healing takes place through formation of new granulation tissue and subsequent epithelialisation.

A non-healing or chronic wound can be defined as one that is failing to progress in a timely fashion through an orderly sequence of repair. Factors that influence healing include:

• The wound’s location
• Skin anatomy and physiology
• The patient’s age and nutritional status
• Co-existing chronic disease
• Infection
• Maceration (when skin turns white or grey, softens and wrinkles because of overhydration) or excoriation (superficial skin loss). Occur when moisture, e.g. wound exudate or urine is trapped against the skin for a prolonged period.

WOUND ASSESSMENT

Thorough assessment of a wound is the basis for an appropriate dressing selection and management plan. Document:

• Site of wound
• Size (area and depth)
• History
• Condition: bed (necrotic, sloughy, granulating, epithelial) and edge (diffuse, cliff-like, undermined, raised)
• Surrounding skin condition
• Evidence of infection
• Odour
• Pain
• Fluid: exudate/pus/serous fluid
• Factors affecting healing
• Previous management

The wound bed

Different types of tissue predominate in the wound bed at different stages of healing. Each needs appropriate management.

Exudate

Strikethrough of exudate can increase the risk of bacterial contamination. Prolonged or heavy exudate production may be caused by infection or colonisation, or contamination by a foreign body. If there is associated oedema, limb elevation may be helpful.

Colonised wound

Organisms have multiplied to the point that they interfere with healing, but have not invaded surrounding tissue. There is no inflammation, or cellulitis, but the tissue is dull, with dark red granulation tissue that bleeds easily. Wound is malodorous, and healing is delayed.

Management aims

• Remove any barrier to healing
• Reduce bacterial load and prevent bacterial proliferation.

Infected wound

Bacteria have multiplied in the wound and are provoking a host reaction. Clinical signs of infection include:

• Increasing exudate
• Unpleasant odour
• Increasing or altering pain
• Cellulitis
• Friable wound bed
• Non-healing or enlarging wound.

Signs of systemic infection include:

• Pyrexia
• Raised white blood cell count
• Raised c-reactive protein.

Management aims

• Remove any barriers to healing
• Reduce infection, bacterial numbers and risk of septicaemia; treat with antibiotics if clinically indicated
• Treat symptoms

LEG ULCER ASSESSMENT

A leg ulcer - a break in the skin on the lower leg that takes more than 6 weeks to heal - is commonly the result of vascular insufficiency: chronic venous hypertension (a venous ulcer, the most common) or of poor arterial blood supply (an arterial ulcer). Because arterial and venous leg ulcers need different management - compression therapy is dangerous for patients with arterial disease - an important part of leg ulcer assessment is to assess arterial sufficiency by calculating the ankle brachial pressure index (ABPI).

ABPI = highest ankle systolic pressure/highest brachial systolic pressure

A hand-held Doppler device and a sphygmomanometer and cuff are used to compare ankle and brachial systolic blood pressure.

VENOUS ULCER

Risk factors

• Deep vein thrombosis
• Thrombophlebitis
• Oedematous legs
• Multiple pregnancies
• Varicose veins
• Previous leg ulceration.

Presentation

• Generally in gaiter area
• Exuding, shallow ulcer with diffuse edge
• Associated with some pain

Staining (pigmentation) of the skin, induration (hardening, ‘woody’ feel), varicose eczema and oedema.

• Atrophie blanche (areas of white skin stippled with red dots)
• ABPI >0.8 on Doppler assessment.

Management aims

• Reduce oedema and pressure in superficial venous system.
• Aid venous return by increasing velocity of flow in deep veins.
• Treat wound according to findings of wound bed.

ARTERIAL ULCER

Risk factors

• Ischaemic heart disease
• Hypertension
• Angina
• Diabetes mellitus
• Intermittent claudication
• Transient ischemic attack
• Myocardial infarction
• Rheumatoid arthritis.

Presentation

• Ulcer generally below ankle
• Dry, deep wound, with 'cliff type' edge
• Dusky-coloured, cold foot
• Pain in lower legs/foot when raised
• Loss of hair on legs
• Atrophic shiny skin on shin
• Thickened toe nails
• Loss of pedal pulses (see Appendix for diagram: location of pulse points)
• ABPI <0.6.

Management aims

• Treat symptoms.
• Treat wound according to assessment of wound bed.
• Reduce the risk of infection.
• If ABPI <0.5, urgent referral to vascular surgeon recommended.

MIXED ULCER (elements of venous and arterial disease)

Presentation

• Venous problems and arterial insufficiency
• ABPI 0.6-0.8 on Doppler assessment

Management aims

• Reduce symptoms
• Treat wound according to assessment of wound bed.

OTHER WOUNDS, INJURIES

Bites - human and animal

Human bites account for 4-23% of bite injuries, and may be particularly prone to infection (occurring in 9-50% of human bites). Complications include septicaemia, septic arthritis and tenosynovitis, and very rarely, tetanus. Dog bites account for 60-90% of bites, and characteristically involve puncture wounds from the canine teeth, and stretch lacerations. Infection occurs in 2-30% of dog bites. Cat bites account for 5-20% of bite injuries and are also prone to infection. Management of any bite involves removal of any foreign bodies e.g. teeth from the wound, encouraging the wound to bleed, thorough irrigation, advising appropriate analgesia and prescribing prophylactic antibiotics if the wound is less that 48 hours old for animal bites, less than 72 hours old for human bites. Refer to A&E for further assessment if wound closure is necessary. Consider the need for tetanus and rabies prophylaxis.

Insect bites and stings

A puncture wound or laceration inflicted by an insect. Most insect bites reactions resolve quickly although more persistent reactions are likely with tick bites. Complications include secondary bacterial infection from scratching, fever and malaise, systemic toxic effects, serum sickness-like reaction (rare) and anaphylaxis. Diseases may be transmitted via an insect bite, e.g. Lyme disease and malaria

Lacerations

Tearing or splitting of the skin caused by blunt trauma or an incision of the skin caused by a sharp object. The most common complication of lacerations is infection, but there may also be injuries to the underlying nerves, tissue and blood vessels. The risk of infection is increased by:

• Diabetes
• Visible contamination
• Increasing age
• Increasing time from injury to repair
• Increasing depth, length and width of the laceration

Injuries – other

Further information is available on a range of injuries at NICE Clinical Knowledge Summaries – select from menu at https://cks.nice.org.uk/specialities/injuries/ 

SUTURING

Sutures (stitches) are the most commonly used method of closing a wound, used after thorough irrigation, exploration and removal of debris. Absorbable sutures dissolve over time (about 2 weeks), non-absorbable sutures need to be removed. Other methods of wound closure include tissue adhesive and Steri-Strips

BURN, SUPERFICIAL

Pink, with blisters, and painful. Skin blanches on pressure. Should heal in 10 days with no scarring. Generally caused by scalding, electrical flash burn, radiation (sunburn).

Management aims

• Control exudate, reduce the risk of infection.
• Promote wound healing, maintain function, provide comfort.

Refer the following burn injuries:

• Those in children
• Those in adults >60 years of age.
• Burns to face, hands, feet or perineum.
• Any flexure or circumferential burn.
• Any chemical or high-tension electrical burn.
• Inhalation injuries.

 

PRESSURE ULCER (decubitus ulcer, bed sore)

Caused by a combination of friction and pressure (and individual contributing factors). 

Management aims

• Reduce risk of infection
• Manage exudate
• Protect surrounding skin
• Remove necrosis or slough

A discharging blind-ended track, extending from the skin surface to an underlying cavity or abscess, eg a pilonidal sinus.

Management aims

• Protect surrounding skin
• Promote granulation from the base of the wound
• Reduce the risk of infection
• Remove necrosis or slough

DRESSING SELECTION

Selection of an appropriate dressing requires familiarity with:

• Wound assessment
• Stages of healing
• Wound management.

Many products are specific to a certain type of wound (acute, chronic, traumatic) or stage of healing. Choice may also depend on patient preference/tolerance, site of the wound and cost. Clinicians must be able to rationalise their choice of dressing and course of action and justify dressing costs. A local formulary of preferred dressings may be provided.

Ideal dressing

An ideal dressing keeps the wound:

• Moist with exudate but not macerated
• Free of clinical infection and excessive slough
• Free of toxic particles, fibres and chemicals
• At an optimum temperature and pH
• Undisturbed by the need for frequent changes.

It should:

• Be non-adherent and easily removable without causing trauma
• Be comfortable and acceptable to the patient
• Produce minimal pain.

For certain wounds, the ideal dressing will also:

• Provide effective wound cleaning (debriding activity)
• Antimicrobial activity (combat localised infection)
• Remove/inactivate proteolytic enymes present in wound fluid
• Provide haemostatic activity.

Dressings available

A variety of dressings are available, including:

• Basic wound-contact.
• Advanced, including hydrogel, vapour-permeable, soft polymer, hydrocolloid, foam, alginate, capillary action, odour absorbent.
• Antimicrobial, incorporating honey, iodine or silver.