Smoke Inhalation
GENERAL PRINCIPLES
Inhalation of smoke represents exposure to a complex mixture of toxic gases and suspended particulate matter. Although the major cause of death in patients with smoke inhalation is cerebral hypoxia related to carbon monoxide exposure, a number of other toxic substances formed during combustion may produce significant pulmonary, cutaneous, and conjunctival injury. These substances include ammonia, hydrochloric acid, sulfur dioxide, hydrogen cyanide, and nitrous dioxide. In addition, when contact is made with lung or skin water, several substances form extremely toxic, corrosive alkalies or acids. These include ammonium hydroxide and nitric, sulfurous, and sulfuric acids. Phosgene, an extremely toxic gas, may be liberated when carbon tetrachloride—containing fire extinguishers are used to treat fires involving chlorinated hydrocarbons.
Clinically, carbon monoxide exposure must always be considered in any patient exposed to excessive smoke because this represents a potentially treatable disorder that if unrecognized may produce serious neurologic sequelae or death.
Clinical Presentation
Patients suffering smoke inhalation may present to the emergency department in a variety of ways. It is important to note that many patients in whom severe pulmonary injury will develop over the next 12 to 24 hours may initially have normal laboratory and radiologic studies and may be completely asymptomatic; therefore, a very conservative approach to therapy is warranted.
Patients’ symptoms include:
Sore throat, hoarseness, dyspnea, cough, and substernal discomfort typically accentuated by inspiration
Headache, dizziness, nausea, and vomiting
Physical signs include:
Tachycardia, tachypnea, stridor, and retractions
The skin color may be normal, cyanotic, or “cherry red” (when carbon monoxide exposure has occurred concurrently).
The possibility of serious pulmonary or inhalation injury is strongly suggested by the following:
A history of containment in a closed space
Situations associated with a reduced level of consciousness (associated with drug or alcohol abuse, seizure, head injury)
Full-thickness facial, perioral, or perinasal burns
Hoarseness, singeing of nasal hair, and burns of the oral mucosa
Carbonaceous sputum
When wheezing is noted initially, a serious and evolving respiratory injury should be suspected.
Laboratory Tests
Arterial blood gases, a carboxyhemoglobin (COHb) level, and a chest x-ray should be obtained initially and will serve as baseline studies. Importantly, even in patients with evolving severe pulmonary injury, these studies may initially be normal and cannot be relied on to exclude or make less likely the diagnosis of inhalation injury.
Criteria for Admission
The initial criteria for admission therefore are clinical in most patients:
Patients likely to have had a respiratory injury based on the history
Patients with a history of loss of consciousness or seizure, amnesia, or other abnormalities of mental status that are otherwise unexplained
Patients with significant CO intoxication
Treatment
Treatment should begin based on the patient’s history.
The administration of humidified, cooled 100% oxygen by a nonrebreathing mask is recommended in all patients.
Bronchodilators are useful if evidence of bronchospasm is present.Related posts:
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