20. Burns Flashcards
A 35-year-old man is brought into the accident department having been
rescued from a house fire. He has burns to his face, arms and trunk but
does not seem to be in much pain.
How would you assess the severity of the burn
This can be assessed in several ways:
- Surface area of a burn may be calculated by:
- Age and % of body surface area burnt are the two most important prognostic factors.
- Classified according to depth
- Surface area
Wallace rule of 9s
Palmar surface. Each of the patients palm areas correlates to ∼0.8% BSA
Lund and Browder charts
- Age and % of body surface area burnt are the two most important prognostic factors.
As a guide: % mortality = BSA of burn + age
Other factors influencing outcome
(and therefore classifying the burn as more severe) are:
Associated inhalational injury (doubles mortality rate)
Co-existent medical problems
- Classified according to depth
A. Partial thickness
- Superficial:
Epidermal
Painful
Red and moist
Blanches - Superficial dermal:
Some superficial dermal damage
Painful
Pale
Blanches - Deep dermal:
Deep dermal damage
Painless but some sensation
Mottled
Non blanching
Delayed bleeding on prick
B. Full thickness
Full thickness
Dermis destroyed
Insensate
Waxy, leathery
Non blanching
Does not bleed
Will need grafting
A burn can be assessed as a major burn if:
- Full thickness burn >10% TBSA (total body surface area)
- Partial thickness burn >25% TBSA (or 20% at extremes of age)
- Burns to hands, feet or perineum
- Inhalational, chemical or electrical burns
- Burns in patients with serious pre-existing medical conditions
- Severe burn is >40% TBSA
How would you initially treat this patient?
Resuscitate the patient according to the ATLS guidelines:
Airway
Administer 100% oxygen via a reservoir mask;
this would also help to treat any CO poisoning.
The upper airway is particularly susceptible to oedema
and subsequent obstruction.
A high index of suspicion should be maintained
with regard to inhalational injury and early intubation
with an uncut tube is frequently needed.
Suxamethonium can be used in the first 24 hours.
It should then be avoided for 2 years
because the increased number of post-junctional receptors
causes prolonged depolarisation and
marked release of potassium.
Breathing
Blood gases should be taken immediately while remembering
that the arterial PO2 is unreliable for predicting CO poisoning.
Early bronchoscopy if there is a risk of inhalational injury.
If there is evidence of this injury, then perform broncho-alveolar lavage
with 20 ml aliquots of 1.4% bicarbonate until the aspirate is clear..
This should be followed by 10 ml instilled via the ET tube and
10 ml nebulised every hour until clear for 6 hours.
Circulation
2 large bore i.v. cannulae should be sited.
These may be difficult to place and may need to be placed through a burn.
Evaluation of volume status and use of a blood pressure cuff may
be difficult in a burned patient.
A urinary catheter and possibly an arterial line will be needed.
One should aim for a urine output of at least 50 ml/hour in this patient.
How would you guide your fluid management?
There are several formulae that can help guide fluid management.
Amongst them are:
Parkland
Muir and Barclay
The time of injury is the starting point for these calculations.
It should be emphasized that these are only a guide
and that assessment of resuscitation should be based clinically #
on heart rate, BP, capillary refill, CVP, urine output,
peripheral and core temperature and the mental state of the patient.
However, a PAFC is used in many centres as there is evidence of poor
correlation between simple clinical parameters (heart rate and urine output)
and the haemodynamics in severe burns.
Parkland
CSL 4 ml/kg per %TBSA in 24 hours (first half givenin 8 hours)
Muir and Barclay
Mount vernon
Brook
0.5 ml PPF/albumin/kg per %TBSA every 4 hours for 12 hours, then 6-hourly for 12 hours 0.5 ml colloid/kg + 1.5 ml crystalloid/%TBSA Half
over first 8 hours
What would make you suspicious of an inhalation injury?
Points in the history:
Explosion
Fire in an enclosed space
Inhalation of toxic fumes
Alcohol intoxication
On examination:
Burnt face
Raised carboxyhaemoglobin levels
Stridor
Soot in the sputum
Burnt eyebrows or nasal hair.
Respiratory distress
Is pain management a problem with burns patients?
Yes.
Apart from the initial injury, they are subjected to multiple dressing
changes and various operations.
They develop tolerance to opioids very
rapidly and therefore may require large doses of opioids and the use of
ketamine, entonox, paracetamol and also anti-depressants.
Other problems you could be asked about:
- Early feeding
High catabolic state. Establishing N/G feeding in the first 4 hours improves outcome
Heat loss
Impaired homeostatic control and heat loss through
burns
Sepsis
Impaired immune function
ARDS
Effects of burn wound mediators/↓plasma oncotic
pressure/↑PAP → Multiple organ failure
Resistance to NMBs
May last 18 months (↑Ach receptors)
Arrhythmias and rhabdomyolysis
Occur with electrical burns
Burn wound excision
Limit to 20% per operation (warm theatre 28−32 ◦C/
big drips/warm fluids/potential for large blood loss)
Haematological Effects
↑Hct for 48 hours − unreliable measure of resuscitation.
↓rbc t1/2. ↓ Platelets due to microaggregation.
Degree of consumption coagulopathy. DIC possible.
Later thrombogenicity
(↓Protein C, S and anti-Th III) → PE
