What are the indications for intubation in patients with inhalation injuries?

From the Guidelines

Intubation should be performed promptly in patients with inhalation injuries showing signs of airway compromise, such as dyspnoea, desaturation, and stridor, as indicated by the most recent guidelines 1. The decision to intubate early in patients with inhalation injuries can be complex and requires careful consideration of the potential benefits and risks.

• The classic features of thermally-induced potential airway obstruction, including hoarseness, dysphagia, drooling, wheeze, carbonaceous sputum, soot in the airway, singed facial or nasal hairs, or a history of confinement in a burning environment, should be taken into account 1.
• However, clinical signs lack sensitivity and are unreliable predictors of the requirement for intubation, and normal nasendoscopic mucosal appearance is reassuring 1.
• The presence of carbon monoxide or cyanide poisoning can worsen tissue hypoxia and compound the emergency, making early intubation crucial 1.
• In the absence of indications for urgent intubation, patients should be observed in a high-dependency area, nursed head-up, and remain nil-by-mouth, with regular reassessment to detect deterioration early 1.
• A more recent study 1 highlights the importance of suspecting smoke inhalation in patients with a history of fire in an enclosed space, presence of soot on the face, dysphonia, dyspnea, wheezing, and/or blackish sputum, and the use of bronchial flexible fibroscopy as the gold standard for diagnosing smoke inhalation.
• However, the impact of fibroscopy on outcomes is uncertain, and it should probably only be performed in patients who have already been intubated, due to the risk of clinical deterioration after the procedure 1.
• The procedure for intubation typically involves rapid sequence intubation using medications such as etomidate or ketamine for induction, followed by a paralytic agent like rocuronium, and a smaller endotracheal tube should be selected due to anticipated airway edema 1.
• Post-intubation management includes lung-protective ventilation strategies with tidal volumes of 6-8 ml/kg, PEEP of 5-10 cmH2O, and FiO2 titrated to maintain oxygen saturation above 92% 1.
• Early intubation is crucial because thermal injury and chemical irritants from smoke cause progressive airway edema that can develop rapidly within hours after exposure, potentially leading to complete airway obstruction 1.

From the Research

Indications for Intubation in Patients with Inhalation Injuries

The decision to intubate a patient with an inhalation injury is crucial and should be based on specific indications. Some of the key indications for intubation include:

• Respiratory distress 2
• Stridor 2
• Hypoventilation 2
• Use of accessory respiratory muscles 2
• Blistering or edema of the oropharynx 2
• Deep burns to the face or neck 2
• Suspicion of inhalation trauma, such as closed-space exposure or facial burns 3
• Upper airway obstruction 4

Assessment and Management

Patients with suspected inhalation injuries should undergo immediate assessment, including:

• Nasolaryngoscopy 5
• Bronchoscopy 4, 5
• Evaluation of the upper and lower airway 5
• Monitoring of ICU severity of illness, sepsis, and acute respiratory distress syndrome 5
• Administration of high concentrations of supplemental oxygen to quickly reverse hypoxia and displace carbon monoxide from protein binding sites 2

Ventilation Strategies

If intubation is required, conventional ventilation using a lung-protective approach is recommended, including:

• Low tidal volume 4
• Limited plateau pressure 4
• Permissive hypercarbia 4
• Various rescue strategies may be necessary if there is a poor response 4