Wounds 3 Flashcards
Wound healing - traditional method
- Traditional method was to “leave it open to the air to dry out”
- Scabs protect the healing wound from ingress of dirt and micro‐organisms
- Thought that bacteria died through dehydration, thus infection minimised
- Migrating polymorphonuclear leucocytes can’t get through dry tissue
- New epithelium forms below wound surface
- Scarring increased
Properties of Dressings
Dressings should ensure that the wound remains:
• Moist with exudate but not macerated
• Free of clinical infection and excessive slough
• Free of toxic chemicals, particles or fibres released by the dressing
• At the optimum temperature for healing to take place
• Undisturbed by frequent or unnecessary dressing changes
• At an optimum pH value
Types of dressing
- Hydrocolloid
- Foam
- Alginate
- Hydrogel
- Tulle
- Absorbent
• Hydrocolloids
Useful for fragile wounds - only need one dressing, have a hydrophobic backing which is vapour permeable, shower-proof
- Microgranular suspension of natural or synthetic polymers (e.g. gelatin, pectin) in adhesive matrix (e.g polyisobutylene)
- Granules semi‐hydrated and hydrophilic
- Adhesive matrix hydrophobic
- Slowly absorb fluid from wound, forming cohesive or hydrophilic gel
- can be cut and layered
- 2mm - 5mm thick, firm
Foams
• Absorbent polyurethane with other compenents: – Hydrocellular foams – Hydropolymer foams – Soft silicone foams – Foam + silver – Foam + charcoal
Alginates
• Seaweed based
• Alginicacid: polymer containing
– Mannuronic acid
– Guluronic acid
• Mannuronic rich alginates form soft flexible gels – Can be rinsed away
• Guluronic rich alginates form firm gels – Can be removed in one piece
• Highly absorbent
- come as dry sheets or ribbons
Hydrogels
• Gels with high water content
– Flat gels (sheets)
– Tubes / containers
• Need a secondary dressing
- add moisture to wound (useful for dead dry tissue to remove it)
Tulles
• Medicated or non‐medicated • Knitted polyester – Low adherence – Open weave – Allow wounds to dry out – Not ideal dressing
- oldest dressing type (knitted)
- skin graft usually taken from thigh or stomach
Vapour permeable films
- Sterile
- Thin
- Conformable
- Hypoallergenic
- Vapour‐permeable
- Adhesive coated
- May have absorbent backing
Absorbent dressings
• Low adherence primary dressing
– Viscose and rayon absorbent pad with adhesive border
– E.g. Mepore, Primapore
Or
– Plastic film faced dressing • Perforated polyester film contact layer • Absorbent cotton pad • Hydrophobic backing – E.g. Melolin
Surgical absorbent dressings
• Conventional dry dressings – Absorbent Cotton BP – Gauze – Lint ( good for fragile dry healthy) – Only on dry wounds!
Moist wound healing
- Moist wound healing first expostulated during WWII
- Winter’s study with pig(s) in 1962 demonstrated increased epithelialisation in moist environment
- Only on superficial wounds, but research was adopted by dressings manufacturers
- Moist conditions allow epidermal cells to migrate to surface of wound, reducing scarring
Useful for fragile wounds - only need one dressing, have a hydrophobic backing which is vapour permeable, shower-proof
Hydrocolloid dressing
Which dressing become more saturated than hydrocolloids
foams
Which foam dressing is used for skin draft or burn
Soft silicone foams
