Wounds Flashcards
Wound definition
Defect or damage in skin caused by chemicals, physical forces, thermal causes or disease
2 broad classifications
Wound without tissue loss: eg surgery
Wound with tissue loss: eg trauma or burn wounds
Incisions
Regular wound
Caused by a clean sharp edged object
Laceration
Rough and irregular wound
Caused by crushing or ripping
Abrasion (graze)
Superficial wound where top layers of skin are lost
Caused by sliding on a rough surface
Puncture
Caused by sharp pointed object punching skin
Chance of anaerobic bacteria infection
Penetration wounds
Caused by entering the body
Avulsion
When the integrity of any tissue in the body is compromised
Where something is basically torn off
Contusions
A bruise
Caused by blunt force trauma
Haematoma
Caused by damage to blood vessel
Blood then accumulates under the skin
3 phases of healing
1) Inflammatory
2) Proliferative
3) Remodelling
Inflammatory phase
Bleeding first to remove toxins
Vasoconstriction begins to stop bleeding
Coagulation initiated by platelets forming fibrin network
Phagocytes engulf dead cells in the wound
Proliferative phase
Granulation tissue builds up in wound space due to fibroblasts and macrophages providing growth factors. (Occurs 2-3 days after wound occurs)
This stimulates fibroplasia and angiogenesis (new blood vessels)
Fibroplasia causes a bed of collagen to fill defect, pulling wound edges together
Remodelling phase
3 weeks after wound occurs
Fibroblasts spur on greater collagen formation which forms a helical structure with inter and intra X links
The tissue will not regain the properties of uninjured tissue
What pericytes?
Pericytes can differentiate into myofibroblasts
Vascular pericytes can enter the wound bed and can assume a more contractile and matrix depositing phenotype
Petroleum impregnated dressing
For clean, healthy and shallow wounds
Use at early stages of wound repair
Use non adhering dressings for exuding wounds such as burns
Hydrogel dressings
Hydrogel sheets- for shallow wounds
Can maintain moisture balance while absorbing exudates
Hydrogel gels- for cavities, good for debriding and dislodging
They donate moisture
Promotes collagenase activity, granulation, epithelisation and contraction
Hypercolloid dressings
For early to mid repair wounds
Reduces pain and promotes angiogenesis
Used where granulation is necessary
For minimal to moderate exudation
Promotes moist wound healing and granulation
Foam dressings
Non adherent
Absorbs large amounts of exudates
For deep wounds with mild to moderate exudates
Best used after granulation to encourage epithelisation and contraction
Alginate dressings
Made brown algae
Good gel/film forming properties
Calcium alginate promotes clotting cascade (10x faster compared to petroleum dressings)
For burns, shearing/avulsion, cavity wounds
Best for moderate to highly exuding wounds
Film dressings
Semi permeable allowing fluid to evaporate whilst still keeping wound moist
Comfortable and resistant to wear/tear
Prevents bacterial colonisation but does not absorb exudate
Natural polymers
Usually protein or polysaccharide in nature
Bio-compatible, degradable and hydrophilic
Does however vary batch to batch and can degrade way too fast
Collagen dressings
The protein is made of three peptide chains with triple helical domains
Promotes healing via attachment and migration
Dry collagen physically absorbs blood and traps them which adheres them to the wound site giving mechanical strength
Chitosan dressings
Made by acetylating chitin
Active in slightly acidic media and releases beta 1-4 linked-D-glucosamine (used for hemorrhage control)
Promotes fibroblasts, collagen deposition and platelet/RBC mobilisation as well as vasoconstriction
Good film forming properties
