A 57-year-old man was brought to the emergency department by Emergency Medical Service (EMS) with burns to the head, face, and chest secondary to smoking while on 2 L·min⁻¹ of oxygen via nasal cannula for COPD. There was no reported loss of consciousness. Albuterol was nebulized, an 18-gauge IV was placed and IV fluids and fentanyl administered. Upon arrival to the emergency department, the patient is awake and alert but in obvious pain with mild respiratory distress. He speaks in full sentences with a hoarse voice. His blood pressure is 152/91, with a heart rate of 112 bpm, breathing 26 times per minute, with an oxygen saturation of 97% while receiving oxygen by non-rebreather, and his temperature is 36.8°C. Lungs sounds are remarkable for diffuse wheezing with fair air movement.

The patient is noted to be 6′3″ tall and weighs 110 kg. Further rapid evaluation reveals deep partial to full thickness burns to the peri-oral region, anterior neck, and upper chest wall. Despite these burns, the patient still has full mouth opening greater than three finger breaths, with a thyromental distance of three finger breaths and the larynx is more than two finger breaths below the hyoid. The Mallampati score is I. The nasal hairs are singed and there is mild erythema to the tongue and posterior pharynx with a small intact blister noted. He has full range of motion of the neck but laryngeal landmarks are difficult to appreciate due to a combination of obesity and burns.

What Are the Airway Evaluation Considerations in This Patient?

Airway evaluation and management for the acute burn patient builds on standard airway evaluation and management with the added complexities associated with both inhalational and external burns, as well as the potential for coexisting toxicological injuries from carbon monoxide and cyanide. In addition, it is critical to consider the potential for the dynamic evolution of inhalational and topical burn injury; an airway initially at low risk for difficulty can progress and become very difficult if edema ensues and leads to obstruction.

This patient currently has predictors of moderate difficulty in all four dimensions of airway management: BMV, direct and indirect laryngoscopy, extraglottic device placement, and surgical airway rescue. The likelihood of toxicological issues is low in this case given there was no prolonged smoke exposure, no loss of consciousness, and mental status is currently normal with relatively reassuring vital signs.

What Are Signs and Symptoms of Inhalational Injury?

Inhalational injury is a major contributor to the morbidity and mortality associated with burns and is a critical component to the evaluation and management of the airway. Inhalational injury is primarily associated with fires in enclosed space, especially when there is loss of consciousness. Signs and symptoms of inhalational injury may include dyspnea, hoarseness, hot potato voice, stridor, respiratory distress, use of accessory muscles, cough, deep burns to the face or neck, singed nares, carbonaceous sputum, and blistering or edema of the oropharynx. Endoscopic evaluation of the upper and/or lower airway is performed in many centers to help with the diagnosis of inhalational injury and to monitor progression.^1,2 Recently, ultrasonic evidence of tracheal thickening has been used as a marker of inhalational injury.³

What Is the Time Course for Airway Injury to Manifest and Worsen and How Does This Impact Decisions?

Airway edema can progress early and rapidly or at anytime during the first 12 to 24 hours, or longer, making airway management significantly more difficult.^4–6 Likewise, burned skin to the face, neck, and torso can become less elastic, and significant swelling can occur from inflammation and third spacing during fluid resuscitation, compounding airway, and ventilation issues. Thus, early intubation has traditionally been emphasized in patients with inhalational injury and may be supported by an increased risk of difficult airway in burned patients intubated in a delayed fashion at burn centers compared to earlier in their course at the initial receiving hospital.⁶ That said, some have suggested that burn patients are intubated at too high a rate, suggesting more sensitive and specific objective methods of evaluation of the likelihood of progression are needed, such as serial nasopharyngoscopic evaluation.^7,8 One study based on retrospective data of patients extubated within 2 days of intubation, suggests lower risk of the need for intubation prior to transfer to a burn center when the burns are non-flame injury (such as scald injury), are not in an enclosed space, are less than 20% total body surface area, not third-degree burns to the face, and the distance to the burn center requires less than 3 hours of transfer time.⁸ When there is concern for inhalational injury and progression of disease, early intubation remains the pragmatic and recommended approach.

What Additional Features of Burns Can Affect the Airway?

Burns to lips, cheeks, and neck can effect access to the larynx, making BMV, EGD placement, and laryngoscopy more difficult. Burns to the neck can impact head positioning, affecting EGD placement, laryngoscopy, and cricothyroidotomy. Likewise, injury and edema to the oropharynx can make BMV, intubation, and EGD challenging. Injury to the trachea, bronchial tree, and lungs can make oxygenation and ventilation difficult, and are particularly worrisome in injuries with steam or other super-heated gases. Importantly, chest wall burns can lead to restricted ventilation and may require escharotomy.

What Toxicities Should be Considered?

Common inhalation and fire-related toxicities include carbon monoxide and cyanide. Screening for carbon monoxide can be performed quickly in the emergency department. In general, burn victims should be treated with 100% oxygen as a presumptive treatment for carbon monoxide poisoning, while simultaneously allowing for denitrogenation in anticipation of airway management. Cyanide toxicity should be considered in any unconscious patients found in a smoke-filled environment. Empiric therapy with cyanocobalamin should be considered along with toxicology consultation. Additional products of combustion contribute to airway injury but most do not have specific diagnostic tests or antidotes. Intoxication with alcohol and drugs are potential comorbid conditions in burn patients and should be considered, along with vigilance for other ingestions associated with a suicide attempt.