When smoke is inhaled, toxic products of combustion injure airway tissues and/or cause metabolic effects. Hot smoke usually burns only the pharynx because the incoming gas cools quickly. An exception is steam, which carries much more heat energy than smoke and thus can also burn the lower airways (below the glottis). Many toxic chemicals produced in routine house fires (eg, hydrogen chloride, phosgene, sulfur dioxide, toxic aldehydes, ammonia) cause chemical burns. Some toxic products of combustion, such as carbon monoxide or cyanide, impair cellular respiration systemically.
Burns and smoke inhalation often occur together but may occur separately.
Upper airway injury usually causes symptoms within minutes but occasionally over several hours; upper airway edema may cause stridor. Significant orofacial burns can cause edema that significantly compounds the upper airway problems created by smoke inhalation.
Lower airway injury may also occur with upper airway injury and usually causes delayed symptoms (eg, oxygenation problems highlighted by increasing oxygen requirements or decreases in lung compliance 24 h or later).
Symptoms of smoke inhalation include
Local irritant phenomena: Cough, wheezing, stridor
Hypoxic manifestations: Confusion, lethargy, coma
Carbon monoxide poisoning: Headache, nausea, weakness, confusion, coma