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Burns Assessment

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Last updated: March 11, 2021
Revisions: 6

Last updated: March 11, 2021
Revisions: 6

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Introduction

Burn injuries can have wide-ranging physical and psychological sequelae, with many patients requiring treatment in specialised centres. In the UK, 130,000 patients present to Emergency Departments with a burn each year.

Whilst most burns are minor, major burns will require close monitoring and management, especially to those of increasing age or with extensive co-morbidities.

Aetiology

Type Description
Thermal Scald Injury caused by hot liquids and steam, common in children and elderly
Flame Direct exposure to fire, can be associated with concomitant inhalation injury
Flash Indirect exposure to flame
Contact   Exposure to a very hot stimulus for short amount of time (e.g. industrial accidents) or exposure to a hot surface for an abnormally long amount of time (e.g. radiator)
Chemical Acid Results in coagulation necrosis to affected tissues
Alkali Results in liquefaction necrosis to affected tissues*
Electrical Direct contact Current from an electrical source passes directly through the body, resulting in an entry and exit wound and can cause significant internal damage
Electrical arc A flash thermal burn occurs due to an electrical arc coming briefly into contact with skin

Table 1 – Classification of burns injury; *Alkaline buns often result in deeper and more severe burns, due to protein denaturation and fat saponification; †Complications of electrical burns include cardiac arrhythmias and rhabdomyolysis

Inhalation Injury

An inhalation injury is damage to the airway, secondary to the inhalation of hot air. Inhalation injury should be suspected whenever an injury is from a flame or smoke exposure in enclosed environment. Mortality in burns increases by 20% when associated with an inhalation injury.

Anyone with features of airway compromise, such as stridor, hoarse voice, or respiratory compromise, post-injury will likely need a definitive airway placed (i.e. intubation). More subtle features to suggest a potential airway injury include singed nasal hairs, facial burns, or soot deposits around the nose.

Nasoendoscopy in suspected cases may show erythema or oedema of airway on direct visualisation, however in those with red flag symptoms, early involvement of anaesthetics for potential intubation should be the priority.

Burn Initial Management

When assessing a patient with burns injury, a thorough A to E assessment is vital. Once performed and the patient stable, try to elicit details regarding the mechanism of the burn, as it can provide clues to the likely depth, associated inhalation injury, and concomitant traumatic injuries

A major burn is any burn with >20% TBSA (>10% in children) of partial or full-thickness burns (i.e. not including superficial burns). Major burns can result in profound inflammatory responses and large fluid shifts occurring, and aggressive fluid resuscitation is often required to mitigate burn shock.

Ensure any source of burning is removed as a priority, as is any non-adherent clothing.

Initial Assessment

The initial assessment of a patient with a burns injury requires an A to E assessment (discussed more here), however there are a few specific points to be aware of for burns patients:

  • Airway
    • Evaluate for signs of inhalation injury; pre-emptive intubation may be required if suspected or high-risk. Remember to protect cervical spine until clinically cleared
  • Breathing
    • Administer 100% oxygen via non-rebreather reservoir mask. In more extensive burns, evaluate the need for escharotomy, especially if circumferential chest burns are present. Obtain an ABG and check carboxyhaemoglobin levels (for carbon monoxide poisoning)
  • Circulation
    • Site two wide bore intravenous cannula (avoiding insertion through burned tissue, if possible) and take routine bloods, including group and screen, clotting, and creatinine kinase. Aggressive intravenous fluid therapy is indicated (discussed later); insertion of a urinary catheter is essential for fluid balance monitoring
  • Disability
    • Evaluate neurological status using the Glasgow Coma Scale and remember to check the temperature, as there is a increased risk of hypothermia
  • Exposure
    • The patient should be fully exposed to get an accurate estimation of the percentage of total body surface area (%TBSA) burned and to check for any concomitant injuries*. Ensure the patient is given a tetanus booster if their status is uncertain.

*Remember that electrical burns may show only a small area of external injury, but have caused significant visceral injury

Intravenous morphine should be used where required for analgesia. Ensure an ECG and CXR are performed, and start a strict fluid balance chart.

Wound dressing protocols vary, however in general, if the patient is to be transferred to higher-level burn care, initially dress the wound with Clingfilm to allow full evaluation of burn depth, whilst minimising fluid losses from the affected wounds.

Hypothermia is a severe risk following burns injury, due to the extensive heat and fluid loss that can occur from the burns sites. As such, assessment in a warmed room, giving warmed fluids if possible, and reducing wound exposure time can all help in limiting hypothermia.

Minor Burns

Rapid and thorough first aid should be performed for all minor burns. General management principles for the management of minor burns starts with removing the source of the burn.

Any non-adherent clothing should be removed, before the wound is cooled under running water for twenty minutes as soon as possible, as this promotes re-epithelialisation.

Assessing Burn Severity

The severity of a burn is generally defined by the percentage total body surface area (%TBSA) burned and burn depth.

Accurate estimation of %TBSA burned is a critical step in guiding appropriate burns management as it determines the initial fluid volume requirements for resuscitation, and whether or not the patient should be considered for transfer to specialist care.

Various techniques can be used to estimate %TBSA, such as Wallace’s Rule of Nines (Fig. 1A), the “Rule of Palm” where the patients palm area represents 1% of their TBSA, or a Lund & Browder Chart (Fig. 1B) which are most used in paediatric cases.

Figure 1 – (A) Wallace’s Rule of Nines (B) Lund & Browder Chart

Assessing Burn Depth

Burn depth approximation is important as it guides therapy (Table 2). More superficial burns may heal spontaneously (albeit are often more painful), while deeper burns may require further intervention (Fig. 2); deeper burns also carry an increased risk of complications.

Burn depth does not, however, guide initial resuscitative efforts and so administration of adequate fluid resuscitation should not be delayed in favour of accurate burn depth evaluation.

Burn Thickness

Deepest Layer Involved

Appearance

Pain

Prognosis

Superficial (first degree) Epidermis Dry, blanching, erythema Painful Heals without scarring, 5-10days
Superficial partial-thickness (second degree) Upper dermis Blisters, wet, blanching, erythema Painful Heals without scarring, <3 weeks
Deep partial-thickness (second degree) Lower dermis Yellow or white, dry, non-blanching Decreased sensation Heals in 3-8 weeks, likely to scar if healing >3 weeks
Full thickness (third degree) Subcutaneous tissue Leathery or waxy white, non-blanching, dry Painless Heals by contracture >8 weeks, will scar

Table 2 – Classification of Burns by Depth

Fluid Resuscitation

Fluid resuscitation following burn injury allows for adequate intravascular volume to limit hypovolaemia, maintain organ perfusion, and minimise tissue ischaemia in the immediate post-burn period.

Fluids are calculated from the time of the burn, not the patient’s hospital arrival time. If the patient is clinically shocked on arrival, this should be corrected prior to calculating any burn fluid requirements.

The modified Parkland formula is the one most commonly used for directing initial fluid requirements. This purely acts as a guide, as every patient should be monitored closely and reassessed regularly to gauge their response to the administered fluid.

The modified Parkland formula* describes the volume of crystalloid fluid (ideally Hartmanns solution) to be administered in the first 24 hours post-burn:

  • Initial 24hrs (Adults): 4mL (Hartmann’s) x Weight (kg) x %TBSA burned
  • Initial 24hrs (Children): 3mL (Hartmann’s) x Weight (kg) x %TBSA burned

50% of the calculated volume is given within the first 8 hours post-burn, and the remaining 50% is given in the remaining 16 hours.

*The modified Parkland formula has been shown to underestimate fluid requirements in patients with large full thickness burns, inhalation injury, or electrical burns

Figure 2 – Types of Burn (A) Superficial (B) Partial (C) Deep

Goal-Directed Therapy

The goal of fluid resuscitation is achieving adequate end-organ perfusion. Due to the systemic inflammation seen in burns patients, conventional markers of fluid balance are not always feasible.

Urine output can be monitored closely as the main marker of fluid balance status, which should be maintained (in adults) at >0.5mL/kg/hr. Other measures include use of mean arterial pressures (MAPs) and blood gas measurements.

Ongoing Care

Depending on the injuries involved, patients with burns may require transfer to either a burns unit or a burns centre (see Appendix):

  • Burn Units are facilities that have a specialised burns ward staffed by skilled burns professionals, capable of caring for moderate level of injury complexity.
  • Burn Centres represent the highest level of inpatient burn care, with immediate operating theatre access and highly-skilled critical care staff, for the management of highly complex burn injuries.

Complications of burns injuries include airway compromise and respiratory failure, fluid loss and electrolyte imbalance, hypothermia, and compartment syndrome.

Key Points

  • As with all unwell patients, ensure a rapid and thorough physiological assessment and management using a structured A to E approach
  • Ensure adequate warming and fluid resuscitation is provided, due to extensive fluid and heat losses that can occur
  • Calculate the degree and extent of the burns, as this will influence need for clinical transfer
  • Complications of burns injuries include airway compromise and respiratory failure, fluid loss and electrolyte imbalances, hypothermia, and compartment syndrome

Appendix

Criteria

Burns Unit

Burns Centre

%TBSA 10-39% ≥40%, or ≥25% with inhalation injury
Depth Deep partial or full-thickness
Site Specialised areas (hands, feet, face, perineum, genitals, over major joint)
Non-blanching circumferential burns
Aetiology Any chemical, electrical, friction, or cold injury require discussion with burns specialists.
Other Suspected non-accidental injury (NAI) Concomitant major trauma with burn injury meeting centre threshold
Pregnant patients Concomitant severe co-morbidities and patients >65yrs with ≥25% TBSA burns
Concomitant trauma with burn injury

Table 3 – Suggested Criteria for Determining the Transfer to Burns Unit versus Transfer to Burns Centre

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