Felis ISSN 2398-2950

Smoke inhalation

Contributor(s): Tad Coles, Rosalind Dalefield

Introduction

Pathogenesis

Etiology

  • Fire smoke contains both toxic gases and particulate matter.
  • Irritants in fire smoke include acrolein, aldehydes, ammonia, chlorine, hydrochloric acid, isocyanates, nitrogen oxide, phosgene, sulfur dioxide.
  • Asphyxiants in fire smoke include carbon dioxide, methane, nitrogen, carbon monoxide and hydrogen cyanide.
  • Particulate matter is irritant and may also carry toxic components into the lungs.

Pathophysiology

  • Airflow restriction.
  • Local immunosuppression.
  • Irritation and destruction of airway mucosa.
  • Simple and/or chemical asphyxia causes hypoxia.
  • Bronchospasm, laryngeal edema and/or casts of desquamated cells and denatured surfactant may limit airflow.
  • Destruction of lung surfactant can cause partial collapse of lungs.
  • Local immunosuppression due to paralysis of mucociliary apparatus, denaturation of surfactant, particulate overload and toxic effects on pulmonary immune cells.
  • Respiratory irritants in smoke damage airway mucosa.
  • Presence of simple asphyxiants such as carbon dioxide, and chemical asphyxiants such as carbon monoxide and hydrogen cyanide may cause hypoxia and narcosis.
  • Hypoxia or toxic gases may cause altered mentation, disorientation, and loss of coordination.
  • Methemaglobin-forming gases may be present causing conversion of iron in heme from the ferrous to ferric form, impairing oxygen-carrying capacity.
  • Ocular irritation and/or narcosis may cause impaired vision, which may in turn trigger agitation and panic.

Timecourse

  • Asphyxiant toxicosis is peracute.
  • Other pulmonary complications, such as secondary bacterial infections, are often delayed.
  • Clinical signs and radiographic changes may not be apparent until 24-72 hours after exposure.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Drobatz K J, Walker L M & Hendricks J C (1999) Smoke exposure in cats - 22 cases (1986-1997). J Am Vet Med Assoc 215 (9), 1312-1316 PubMed.
  • Guy J S & Peck M D (1999) Smoke inhalation injury: pulmonary implications. Medscape Respiratory Care (2).
  • Lee-Chiong T L Jr. (1999) Smoke inhalation injury. Postgrad Med 105 (2), 55-62 PubMed.

 


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