Thermal Burn Evaluation and Management

Overview

This StatPearls review by Walker and King, last updated in May 2023, covers the assessment and treatment of thermal burns. The WHO estimates 6.6 million injuries and 300,000 deaths a year, with about 95% of deaths in low-income countries. Flash and flame burns account for most adult admissions and scalds for most paediatric ones.

Causes and pathophysiology

Thermal burns arise from flame or flash exposure, scalds and contact with hot objects, and grease and hot-oil burns are often deeper than they first look. Locally the wound has a central zone of coagulation, a surrounding zone of stasis, which can be saved with proper resuscitation and wound care, and an outer zone of hyperaemia. Large burns trigger a systemic inflammatory response with capillary leak, hypotension and organ hypoperfusion, and true inhalation injury raises mortality.

Assessment

Superficial burns heal in 3 to 5 days, superficial partial-thickness burns in 10 to 15 days and deep partial-thickness burns in 3 to 5 weeks with scarring, while full-thickness burns are painless, leathery and need surgery, and fourth-degree burns reach muscle or bone. Burn size (TBSA of second-degree or deeper burns) is estimated with the Wallace rule of nines in adults or the Lund-Browder chart in children. Circumferential burns must be watched for compartment syndrome, and patterns that do not fit the history should raise suspicion of abuse. Laboratory tests, imaging for associated trauma and carboxyhaemoglobin are obtained, but a low level hours after injury does not exclude inhalation injury because its half-life is 4 hours or less on 100% oxygen.

Management

The patient is treated first as a trauma patient (airway, breathing, circulation). Transfer to a burn centre is considered for partial-thickness or deeper burns of 10% TBSA or more, burns of the face, hands, feet, genitalia or major joints, chemical or electrical burns, inhalation injury, and burns with major trauma or significant comorbidity. The American Burn Association consensus uses 20% TBSA as the threshold for formal resuscitation. The Parkland formula (4 mL x %TBSA x kg) and the modified Brooke formula (2 mL x %TBSA x kg) give a 24-hour volume of lactated Ringer's, half in the first 8 hours, titrated to a urine output of 0.5 to 1 mL/kg/h, and over-resuscitation is as harmful as under-resuscitation.

Wound care and surgery

Silver sulfadiazine is the most used topical agent, silver nitrate suits patients with sulfa allergy and mafenide is reserved for deep, contaminated or ear burns. Deep partial-thickness and full-thickness burns are excised and covered with split-thickness skin grafts, ideally within 10 days.

Prognosis and first aid

Percentage TBSA, inhalation injury and age are the best predictors of mortality, and complications include wound infection, sepsis, anxiety and depression. First aid means stopping the burning, removing burnt clothing and jewellery, cooling with running water for 3 to 5 minutes (30 to 40 minutes for chemical burns), avoiding ice and ointments, covering with a clean dry dressing and keeping the person warm.