Airway Burns and Smoke Inhalation Injuries

  • Clinical features of airway burns include soot in the airway, stridor, hoarseness, singed nose hair, and mucosal ulceration
  • Historically, survivors of explosions and fires in enclosed spaces are more likely to have suffered airway burns
  • Consequences of theramal inhalation injury include acute thermal damage to airway  structures, delayed inflammatory damage, and systemic effects of the inhaled substance (eg. carbon monoxide poisoning)

Out of all the possible complications of burns, the college examiners have been most interested in airway burns, and specifically in the various clinical features which alert you to the presence of such burns. Question 11 from the first paper of 2013, Question 13 from the second paper of 2006 and Question 11 from the second paper of 2000 are virtually identical: they all ask about airway burns, smoke inhalation injury and other forms of thermal damage to the upper respiratory tract.

Features of history and examination associated with airway burns

Historical features associated with airway burns

  • Explosions
  • Fires in an enclosed space
  • Exposure to heated steam
  • Fires involving volatile solvents
  • Corrosive ingestion
  • Laryngeal surgery (using a laser)

Clinical features of airway burns

  • Stridor, hoarseness, or cough
  • Burns to face, lips, mouth, pharynx, or nasal mucosa
  • Soot in sputum, nose, or mouth ("carbonaceous material"
  • Singed vibrissae (the zoological term for innervated whisker hairs, misapplied to the coarse nasal hair which grows in human nostrils and has no role in tactile sensing)
  • Bronchocopic findings of tracheal erythema, oedema or or ulceration.
  • Dyspnoea, decreased level of consciousness, or confusion
  • Hypoxaemia (low pulse oximetry saturation or arterial oxygen tension) or increased carbon monoxide levels (>2%)

Pathophysiologic consequences of airway burns

Mechanisms organised by pathophysiological mechanism

Mechanism

Specific factors

Clinical features Management
Thermal
  • Exposure to flames
  • Splash with corrosives
  • Inhalation of superheated smoke or steam
  • Facial burns
  • Burns of the mucosa
  • Soot on lips
  • Carbonised material in the pharynx
  • Carbonised material in sputum
  • Early assessment of airway patency
  • Examination of the upper airway
  • Serial assessments
  • Upright positioning
  • Suctioning of upper airway secretions
  • Early elective intubation
  • Referral to ENT for tracheostomy in case of severe burns, if strictures are anticipated
Inflammatory
  • Thermal damage to mucosa
  • Effects of inhaled particles
  • Mucosal oedema
  • Pharyngeal oedema
  • Vocal cord oedema
  • Tracheal oedema
  • Difficulty swallowing
  • Hoarse voice
  • Cough
  • Stridor
  • Wheeze
  • Increased work of breathing
Inhaled agents
  • Carbon monoxide
  • Cyanide
  • "Cherry red" complexion
  • Hypoxia despite normal SpO2 readings

Mechanisms organised by anatomical location

Mechanisms, Clinical Features and Management of Upper Airway Burns
Anatomical location

Mechanism

Clinical features Management
Face
  • Exposure to flames
  • Splash with corrosives
  • Facial burns
  • Early assessment of airway patency
  • Examination of the upper airway
  • Serial assessments
  • Upright positioning
  • Suctioning of upper airway secretions
  • Early elective intubation
  • Referral to ENT for tracheostomy in case of severe burns, if strictures are anticipated
Oral cavity
  • Exposure to flames
  • Splash with corrosives
  • Soot on lips
  • Burns of the mucosa
  • Mucosal oedema
Pharynx
  • Inhalation of superheated smoke or steam
  • Carbonised material in the pharynx
  • Pharyngeal oedema
  • Difficulty swallowing
Larynx
  • Inhalation of superheated smoke or steam
  • Hoarse voice
  • Cough
  • Vocal cord oedema
  • Stridor
  • Increased work of breathing
Trachea
  • Inhalation of superheated smoke or steam
  • Stridor
  • Wheeze
  • Tracheal oedema
  • Carbonised material in sputum

 

References

Lund, Tjostolv, et al. "Upper airway sequelae in burn patients requiring endotracheal intubation or tracheostomy." Annals of surgery 201.3 (1985): 374.

Bartlett, Robert H., et al. "Acute management of the upper airway in facial burns and smoke inhalation." Archives of Surgery 111.7 (1976): 744-749.

Gaissert, Henning A., Robert H. Lofgren, and Hermes C. Grillo. "Upper airway compromise after inhalation injury. Complex strictures of the larynx and trachea and their management." Annals of surgery 218.5 (1993): 672.

Bishop, Sophie, and Simon Maguire. "Anaesthesia and intensive care for major burns." Continuing Education in Anaesthesia, Critical Care & Pain 12.3 (2012): 118-122.

McFadden, E. R., et al. "Thermal mapping of the airways in humans." Journal of Applied Physiology 58.2 (1985): 564-570.

Lund, Tjostolv, et al. "Upper airway sequelae in burn patients requiring endotracheal intubation or tracheostomy." Annals of surgery 201.3 (1985): 374.

Tredget, EDWARD E., et al. "The role of inhalation injury in burn trauma. A Canadian experience." Annals of surgery 212.6 (1990): 720.