What are the effects of smoke inhalation?

Updated: Oct 15, 2021
  • Author: Keith A Lafferty, MD; Chief Editor: Joe Alcock, MD, MS  more...
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Smoke inhalation injury was described as early as the first century CE, when Pliny reported the execution of prisoners by exposure to the smoke of greenwood fires. Smoke—the vaporous colloidal system formed when a material undergoes combustion or pyrolysis—comprises a collection of noxious gases, airborne solid particles, and airborne liquid particles. The distribution of those particles in the respiratory tract after inhalation is determined by their size and by the person’s breathing mechanics and tidal volume.

During fires, smoke inhalation victims are unable to efficiently breathe through the nasopharynx, thereby decreasing inspiratory air filtration and enabling a greater amount of particle distribution in the airway. This subsequently leads to nasopharyngeal irritation and severe lung injury.

Inhalation injury from smoke in fires may account for as many as 60-80% of fire-related deaths in the United States, many of which are preventable. [4, 5] Excellent care rendered at today's burn centers has greatly reduced the mortality from surface burns, [6] while the mortality from pulmonary injury has been increasing.

Many victims of fire accidents have both smoke inhalation and thermal injury. In fact, the co-presence of bronchopulmonary injury with cutaneous burns that exceed 30% of the total body surface area causes the mortality rate to increase more than 70%. [7] Other studies have shown that the incidence of inhalation injury increases with increasing burn size. [2]

Smoke inhalation may produce injury through several mechanisms. Heated air from a fire can cause significant thermal injury to the upper airway. Particulate matter produced during combustion (soot) can mechanically obstruct and irritate the airways, causing reflex bronchoconstriction. Noxious gases released from burning materials include carbon monoxide (CO) and hydrogen cyanide (CN).

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