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

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.