PBL 1 Flashcards
describe the Jackson model of burns?
in the centre of the burn we have the coagulation zone with the stasis zone around that and then the hyperaemia zone around that
what is the zone of coagulation in a burn?
the point of maximum damage where there is irreversible tissue loss due to necrosis
what is the stasis zone of a burn?
where we get decreased perfusion and if not reversed this can become complete necrosis
what is the zone of hyperaemia in a burn?
where tissue perfusion is increased
what can cause a burn?
fire, heat, chemicals, electricity and radiation
describe a superficial/first degree burn?
damage is caused only to the epidermis
the skin is red, dry with no blisters. it should have brisk capillary refill and is mildly painful
whats an example of a first degree burn?
sunburn
describe the pathophysiology of a second degree burn?
damage caused to the epidermis and papillary dermis
what does the skin look like on a second degree burn?
red, moist, blistered swollen and very painful
why do burns cause pain?
the release of pro-inflammatory cytokines stimulate sensory nerve endings
why can burns result in hypotension?
because cytokines increase vascular permeability, causing fluid to leak out and cause interstitial oedema
why do we get blanching and erythema of the skin in burns?
because cytokines cause vasodilation
what are blisters?
the accumulation of fluid in an area
what do second degree burns look moist?
because we get the formation of blisters which burst
what is damaged in third degree burns?
the epidermis, dermis and hypodermis
so all blood vessels and nociceptors
what does the skin look lik in third degree burns?
dry, non-blanching, charred, patchy in colour (white-> brown), dry leathery texture
why do third degree burns have little or no pain?
because damage is caused to sensory nerve fibres and nociceptors leading to hypoaesthesia
why can we get hypotensive from 3rd degree burns?
because any blood vessels which havnt been completely destroyed react to cytokines and this causes increased vascular permeability = oedema
what is damaged in fourth degree burns?
all layers of the ski and even some muscles, tendons and bone
what do fourth dgeree burns look like?
brown, dry, charred
can you feel any pain with fourth degree burns?
NOTHING
how do we measure the total body surface area burned?
using the rule of nines
outline the rule of nines?
front + back of head = 9% front + back of arm and hand = 9% chest + stomach = 9% upper back = 9% lower back = 9% front and back of 1 leg + foot = 18% genital area = 1%
how much a total body surface area must be burnt for it to be considered a major injury and require hospitalization?
children- 10%
adults 15-20%
at what total body surface area of burns should you worry about hypovolemic shock?
over 15%
what is hypovolemic shock?
an emergency condition in which severe blood/other fluid loss makes the heart unable to pump enough blood to the body
when should you go to hospital with a burn?
if the burn is larger than the hand if the burn is on the face. hand, buttox, feet or over a major joint causes white or charred skin forms blisters all chemical/electrical burns when the person appears to be in shock if the person is pregannt if the person is over 60 or under 5 if the person has a medical condition or a weakened immune system
outline first aid of a burn?
stop the burning process remove any clothing or jewellery nearby dont remove anything stuck to the burn keep the burn cool with running water for 20 minutes keep the person warm to prevent hypothermia cover burn with clingfilm treat pain sit upright if face or eyes are burnt
how often should you change the dressing on a burn?
every day with clean hands
which burns may need skin grafts?
second, third or fourth degree burns
how do superficial wounds heal?
the epidermis can regenerate from the stratum basale
what are the stages for healing deeper wounds?
haemostasis
inflammation
proliferation
remodelling
what happens in the haemostasis phase of wound healing?
vasoconstriction, platelets adhere to sub-endothelium, fibrin stands form a mesh, coagulation of blood and formation of a thrombus
what happens in the inflammatory phase of wound healing?
damaged cells and pathogens are removed from the wound area
swelling, heat, pain and redness
what happens in the proliferative phase of wound healing?
angiogensis, fibroplasia (fibroplasts contract wound and collagen is laid down), epithelialisation (keratinocytes laid down)
what happens in the remodelling phase of wound healing?
collagen is remodelled from type 3 to type 1 and is re-aligned along tension lines with cross-linking
unneeded cells are removed by apoptosis
