Burns Injury Flashcards
Define burns. Where can heat originate from?
Burns are very common injuries, predominantly to the skin and superficial tissues, caused by heat from:
- hot liquids,
- flame, or
- contact with heated objects,
- electrical current, or
- chemicals.
How common are burns/deaths from burns? What % are non accidental in children?
An estimated 180 000 deaths every year are caused by burns – the vast majority occur in low- and middle-income countries.
Rate of child deaths from burns is over 7 times higher in developing than in developed countries
Many do not seek medical advice so prevalence of burns is difficult to determine
Approximately 20% of burns in younger children involve abuse or neglect.
How are burns classified?
1st (epidermis only) to 4th (involve subcut tissue, tendon, bone) degree
What is a first/second degree burn? Give examples of when these would occur.
First-degree burns:
- Erythema involving the epidermis only
- Usually dry and painful
- Typical of severe sunburn.
Second-degree burns:
- Superficial partial-thickness burns involving the epidermis and upper dermis
- Deep partial-thickness burns involving the epidermis and dermis
- Usually wet and painful
- Typical of scalding injury.
What is a third/fourth degree burn? Give an example of a cause for each.
Third-degree burns:
- Full-thickness burns involving the epidermis and dermis and damage to appendages
- Usually dry and insensate
- Typical of flame or contact injury.
Fourth-degree burns:
- Involve underlying subcutaneous tissue, tendon, or bone
- Typical of high-voltage electrical injury.
How do you assess burn size? Why is it important to assess size?
Burn size influences the size of the inflammatory response (vasodilation, increased vascular permeability) and this shift from intravascular volume.
Lund and Browder charts or the “rule of nines” are used to assess burns:
- (arm: 9%; front of trunk 18%; head and neck 9%; leg 18%; back of trunk 18%; perineum 1%)
How do you assess burn depth? Why is it important?
Burn depth determines healing time/scarring
Assessment can be hard even for experiences - must distinguish whether partial thickness or full thickness.
- Partial - painful, red, blistered
- Full - insensate, painless, grew-white
NB: burns can evolve in the first 48 hours esp.
Explain the systemic effects of burns.
When burn is >20% of TBSA –> fluid loss, release of vasoactive mediators from injured tissue –> capillary leak, interstitial oedema, organ dysfunction (traditionally treated with crystalloid but more recently with colloid)
In resuscitated individuals this will stop and be replaced by a hypermetabolic response –> doubling in cardiac outout and resting energy expenditure in 24-48hrs, accelerated gluconeogenesis, insulin resistance, and increased protein catabolism
Subsequent events are determined by the wound e.g. if clean it is then colonised by endogenous bacteria which multiply –> proteases liquefy the eschar –> separates –> bed of granulation tissue or healing burn depending on depth
What investigations should you do in burns injuries?
Bloods:
- FBC- low Hct; hypovolaemia; neutropenia; thrombocytopenia
- Metabolic panel - high urea, creatinine, glucose; hyponatraemia; hypokalaemia
- Carboxyhaemoglobin (COHb) - high in inhalation injury
- ABG - metabolic acidosis in inhalation injury
- Fluorescein staining - for subtle corneal burns to assess damage
Imaging:
Based on injury type
Wound
- biopsy culture - do if sepsis suspected
- histology - as above
How do you manage burns? (summary)
Resuscitate
Arrange transfer to burns unit for all major burns (>25% partial thickness in adult and >20% in children)
Assess site, size, depth (to help calculate fluid requirements)
NB: still refer to burns if:
- full thickness >5% or partial >10% in adults
- >5% partial in children or the elderly
- burns in special sites
- chemical, electrical burns
- burns with inhalational injury
Describe an ABC management of burns.
Airway
- Beware of ubstruction esp if hot gases inhaled. Clues: hx enclosed space, soot in oral/nasal cavity, singed nasal hairs, hoarse voice
- Fexible laryngo/bronchoscopy is useful
- Consider early intubation
- Obstruction can develop in first 24 hours
Breathing
- Exclude chect injury (e.g. tension pneumothorax) and constricting burns
- Consider escharotomy if chest burns are impairing thorax excursion
- Give 100% O2
Circulation
- Partial thickness burns >10% in child and >15% in adult require IV resuscitation
- Put in 2 large bore (14G or 16G) IV lines - secure well
- Can be put in through burned skin
- Interosseous access in infants/adults
How do you relieve pain and anxiety in burns patients?
Attention to pain and anxiety are essential in all phases of care. This is usually done by infusion of opioids and benzodiazepines (e.g., morphine and midazolam).
What should you do if you suspect CO poisoning? What are the clues? Is SpO2 reliable?
Suspect CO poisoning from hx, cherry-red skin, carboxyhaemoglobin level (COHb) - with 100% O2 half life of COHb falls from 250min to 40min
Consider hyperbaric O2 if:
- pH<7.1
- CNS signs
- >25% COHb
- >20% COHb if pregnant
SpO2 is unreliable in CO posioning
What size burns require IV fluid resuscitation?
Partial thickness burns >10% in child and >15% in adult require IV resuscitation
Which formula can be used to calculate volume of Hartmann’s solution which should be given in 24h?
Parkland formula (popular): 4 × weight (kg) × % burn = mL
Half of total should be given in first 8hrs
Formula is only a guideline - adjust according to clinical response and urine output.
List 2 examples of crystalloid and 2 examples of colloid solutions.
What are 3 differences between crystalloids and colloids?
