Burns Flashcards
What is a burn?
An injury to a tissue caused by heat, friction, electricity, radiation or chemicals
The different types of burns are:
Chemical (acid/alkali)
Thermal (excess heat or cold)
Electrical (low or high voltage)
Radiation (UV or ionising)
How do acid and alkali burns occur?
Acid - coagulative necrosis
Alkali - liquefactive necrosis
Describe the pathophysiology of a burn?
Described by the Jackson’s burn model:
- Central zone (coagulative necrosis, irreversible)
- Zone of stasis (inflammation and ischaemia, salvageable)
- Zone of hyperaemia (vasodilation and capillary leakage)
What are the important inflammatory mediators in burns?
Histamine
Prostaglandin E2
Bradykinins
Leukotrienes
Serotonin
How to classify burns?
Based on cause
Based on depth:
- Superficial = epidermis only
- Partial thickness (divided further into superficial partial = epidermis + upper dermis, and deep partial = extends into deeper dermis)
- Full thickness = entire dermis +/- underlying tissue
What are the characteristics of the different depths of burns?
Superficial: erythema, normal capillary refill, painful, heals by epithelialisation, no blistering
Superficial partial: blistering, skin is still pink with capillary refill
Deep partial: skin is red, capillary refill may be delayed, some areas may be less painful
Full thickness: not painful, absent capillary refill, white and leathery
How to describe a burn?
Depth
Extent (total body surface area percentage)
Methods of calculating the extent:
- Rule of Palm = assumes that the entire palm including fingers represents 1%
- Wallace Rule of 9 = each arm = 9%, each leg is 18%, head is 9%, anterior trunk is 18%, posterior trunk is 18%, perineum is 1%
- Lund and Browder Chart = these are thought to be more accurate with separate versions for adults and children
What is the initial management of a burns patient?
First aid measures - ensure safety, remove causative agent if possible, remove clothing and jewellery, irrigation with cold NOT ICY water
Follow ATLS protocol:
- Airway - assess for possibility of inhalation injury, contact anaesthetist for intubation if in doubt
- Breathing - assess for mechanical restriction from circumferential burns -> may require escharatomy, look for signs of CO poisoning
- Circulation - assess the need for fluid replacement and monitoring with a catheter
- Disability - AVPU
- Exposure - head to toe exam but keep warm, assess TBSA
How is CO poisoning treated?
High flow 100% oxygen
When is fluid resuscitation required in burns?
Adults: >20% deep partial or full thickness burns
For children, the threshold is 10%
What is the Parkland Formula for calculating the fluid volume required?
TBSA% x weight in Kg x 2-4ml
First 50% administered over 8 hours, second 50% administered over 16 hours
What are the goals of the secondary survey?
Preventing hypothermia
Preventing stress ulcers - Curling’s ulcer
NG tube for nutrition
Consider tetanus jab
Consider need for escharatomy
Antibiotics are not usually indicated unless there is a suspected infection
Which patients need to be transferred to a regional burns unit?
Consider the amount of burn, where the burn is, the type of burn, and patient factors
Amount:
Full thickness burns > 5%, partial thickness > 10% in adults or > 5% in children
Location:
Burns to the face, hands, feet, perineum, genitalia and major joints
Type:
Chemical and electrical
Circumferential
Burns in the presence of other major trauma
Non-accidental injury
Patient:
Very young
Very old
Pregnant
Which formula is used to calculate prognosis after a burn?
Baux score:
Age + TBSA should be less than 100
If > 100, chance of survival is less than 20%
What are the systemic effects of burns?
Respiratory: ARDS
Cardiovascular: reduced cardiac output, hypovolaemia, end organ failure
Gastrointestinal: stress ulcers
Other: DIC, coagulopathy, hypothermia, electrolyte disturbances
