Wound dressings

The 'Ideal Wound Dressing' should:

Maintain a moist environment at wound interface
Remove excess exudate without allowing 'strike through’ to surface of dressing
Provide thermal insulation and mechanical protection
Act as a barrier to micro-organisms
Allow gaseous exchange
Be no adherent and easily removed without trauma
Leave no foreign particles in wound
Be non-toxic, non-allergenic and non-sensitising
No single dressing is appropriate for all wound types and all stages of healing

Hydrocolloids e.g. Granuflex

Matrix of cellulose and other gel forming agents - gelatin and pectin
Occlusive dressing
Should be avoided if infection particularly with anaerobic organisms
Promotes autolysis and aids granulation
Can remain in place for up to a week
Over-granulation can occur

Alginates e.g. Kaltostat

Calcium and sodium salts of alginic acid obtained from seaweed
Highly absorbent
Useful in medium to heavily exudating wounds
Secondary covering is required
Forms a gel in contact with wound exudate

Foam dressings e.g. Lyofoam

Useful for moderately exudating wounds
Prevents 'strike through' of exudate to wound surface
Desloughs wounds by maintaining a moist environment

Hydrogels e.g. Intrasite Gel

High water content creates a moist wound surface
Debrides wounds by hydration and promotion of autolysis
Will absorb a light exudate
Not appropriate for heavily exudating wounds

Debriding agents

Remove eshcar and necrotic tissue
Do not maintain moist environment
Need frequent changes
Varidase = streptokinase
Aserbine = malic, benzoic and salicylic acids in a cream base
Damages granulation tissue and delays healing

Negative pressure topical dressings

Negative pressure topical dressings apply negative pressure via a foam dressing
They remove wound exudate and reduce extravascular and interstitial fluid
They improve blood supply during the phase of inflammation
The mechanical effect stimulates cellular proliferation
Shown to be effective in open wounds

Mechanism of use

Foam dressing is cut to shape of wound
Foam is either polyurethane or polyvinyl-alcohol
Foam is covered with adhesive dressing with a small hole
Therapeutic regulated accurate care (TRAC) pad applied over the hole
TRAC pad is connected to a negative pressure generator
Pressures achieved at TRAC pad - foam interface are regulated
Pressure used is approximately 125 mmHg
Intermittent application of pressure may be advantageous
Dressings are changed every 48-72 hours

Wounds suitable negative pressure topical dressings

Acute wounds
- Trauma
- Burns
Chronic wounds
- Pressure sores
- Leg ulcers
Salvage procedures
- Wound dehiscence
- Wound infection
- Necrotising fasciitis
Adjunct to surgery
- Skin grafts
- Flap surgery
- Wound bed preparation

Contraindications

Grossly infected wounds
Bleeding wounds
Malignancy
Exposed blood vessels

Bibliography

Dinah F, Adhikari A. Gauze packing of open surgical wounds: empirical or evidence based practice? Ann R Coll Surg Engl 2006; 88: 33-36.

Jones S M, Banwell P E. Shakespeare P G. Advances in wound healing: topical negative pressure therapy. Postgrad Med J 2005; 81: 353-357.

Morykwas M J, Simpson J, Punger K et al. Vacuum-assisted closure: state of basic research and physiologic foundation. Plast Reconstr Surg 2006; 117 (7 Suppl): 121S126S

Vermeulen H, Ubbink D, Goosens A et al. Dressings and topic agents for surgical wounds healing by secondary intention. Cochrane Database Syst Rev 2004: CD003554.