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Smoke Inhalation

Smoke Inhalation Overview

The number one cause of death related to fires is smoke inhalation. An estimated 70% of fire deaths are the result of smoke inhalation injuries rather than burns.

Smoke inhalation occurs when you breathe in the products of combustion during a fire. Combustion results from the rapid breakdown of a substance by heat (more commonly called burning). Smoke is a mixture of heated particles and gases. It is impossible to predict the exact composition of smoke produced by a fire. The products being burned, the temperature of the fire, and the amount of oxygen available to the fire all make a difference in the type of smoke produced.

Smoke Inhalation Causes

Smoke inhalation damages the body by simple asphyxiation (lack of oxygen), chemical or thermal irritation, chemical asphyxiation, or a combination of these. 

Simple asphyxiants

  • Combustion can use up oxygen near the fire and lead to death when there is no oxygen left to breathe
  • Smoke itself can contain products that do not cause direct harm to you, but that take up the space needed for oxygen. Carbon dioxide, for instance, acts in this way.

Irritant compounds

Combustion can result in the formation of chemicals that cause direct injury when they contact your skin and mucous membranes. These substances disrupt the normal lining of the respiratory tract. This disruption can potentially cause swelling, airway collapse, and respiratory distress. Examples of chemical irritants found in smoke include sulfur dioxide, ammonia, hydrogen chloride, and chlorine.

In addition, the high temperature of the smoke can cause thermal damage to the airways.

Chemical asphyxiants

A fire can produce compounds that do damage by interfering with your body’s oxygen use at a cellular level. Carbon monoxide, hydrogen cyanide, and hydrogen sulfide are all examples of chemicals produced in fires that interfere with the use of oxygen by the cell.

If either the delivery of oxygen or the use of oxygen is inhibited, cells will die. Carbon monoxide has been found to be the leading cause of death in smoke inhalation.

Smoke Inhalation Symptoms

Numerous signs and symptoms of smoke inhalation may develop. Symptoms may include cough, shortness of breath, hoarseness, headache, and acute mental status changes.

Signs such as soot in airway passages or skin color changes may be useful in determining the degree of  injury.

  • Cough: When the mucous membranes of the respiratory tract get irritated, they secrete more mucus. Bronchospasm and increased mucus lead to reflex coughing. The mucus may be either clear or black depending on the degree of burned particles deposited in the lungs and trachea.
  • Shortness of breath: This may be caused by direct injury to the respiratory tract leading to decreased oxygen getting to the blood. The blood itself may have decreased oxygen-carrying capacity. This could be the result of chemicals in the smoke or the inability of cells to use oxygen.
    This can lead to rapid breathing resulting from the attempt to compensate for these injuries.
  • Hoarseness or noisy breathing: This may be a sign that fluids are collecting in the upper airway where they may cause a blockage. Also, chemicals may irritate vocal cords, causing spasm, swelling, and constriction of the upper airways.
  • Eyes: Eyes may become red and irritated from the smoke. The corneas may also have burns on them.
  • Skin color: Skin color may range from pale to bluish to cherry red.
  • Soot: Soot in the nostrils or throat may give a clue as to the degree of smoke inhalation. Inhalation can lead to nostrils and nasal passages swelling.
  • Headache: In all fires, people are exposed to various quantities of carbon monoxide. Even if there are no respiratory problems, carbon monoxide may still have been inhaled. Headache, nausea, and vomiting are all symptoms of carbon monoxide poisoning.
  • Changes in mental status: Chemical asphyxiants and low levels of oxygen can lead to mental status changes. Confusion, fainting, seizures, and coma are all potential complications following smoke inhalation.

WebMD Medical Reference from eMedicineHealth

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