Question 11

Discuss the mechanism, clinical symptoms and management of upper respiratory tract injuries due to burns.

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College Answer

Upper respiratory tract bums can be life threatening unless appropriately recognised and treated. Severity of inhalational injury has been related to various factors: beat of inhaled gases, composition of gases (presence of particles, steam and toxic products), duration of exposure, and pre·injury state.
Most of the upper .respiratory tract injury is due to the thermal insult (augmented by duration of exposure).

Initial symptoms may relate to associated injuries (facial burns), early oedema (intra-oral, pharyngeal, supraglottic/glottic/subglottic) with respiratory distress secondary to airway obstruction and increased work of breathing (tachypnoea, indrawing of soft tissues, tracheal tug), and patient · may be coughing or spitting carbonaceous material (signs are those of upper airway burn).

Management includes that of associated systemic effects such as bums to body (hypovolaemic shock etc), and inhalation of toxins (carbon monoxide, cyanide etc.). Management of the airway includes appropriate positioning of patient (eg. sitting up), close monitoring, and early definitive management of airway patency. Oedema worsens over the first few hours (persists for days) and may rapidly cause airway obstruction in untreated patients. Elective intubation should be considered early. A safe technique which took into account the potential for full stomach and difficult intubation was expected to be detailed.

Discussion

Smoke inhalation is dealt with more broadly in Question 13 from the second paper of 2006. The lower respiratory complications of smoke inhalation are treated in greater detail in the answr toQuestion 26 from the first paper of 2012.

Apart from organising them by mechanism, symptoms and management, upper respiratory tract complications of smoke inhalation can be categorised by pathophysiology or anatomically, to make for a systematic answer.

Presented in this fashion, it could even be turned into a table.

Everyone likes tables.

Mechanisms, Clinical Features and Management of Upper Airway Burns
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

Or, one can organise them 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

A good summary of airway burns can be found in the 2012 article

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.

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