Smoke inhalation

Definition

Smoke inhalation is breathing in the harmful gases, vapors, and particulate matter contained in smoke.

Description

Smoke inhalation typically occurs in victims or firefighters caught in structural fires. However, cigarette smoking also causes similar damage on a smaller scale over a longer period of time. People who are trapped in fires may suffer from smoke inhalation independent of receiving skin burns ; however, the incidence of smoke inhalation increases with the percentage of total body surface area burned. Smoke inhalation contributes to the total number of fire-related deaths each year for several reasons: the damage is serious; its diagnosis is not always easy because as of 2004 there were no sensitive diagnostic tests; and people may not show symptoms until 24 to 48 hours after the event.

Demographics

According to the National Safety Council, 3,900 people died from exposure to fire, flame, and smoke in the United States in 2001, the most recent year as of 2004 for which data were available. Smoke inhalation accounts for the majority of deaths in home fires. Children under age 11 and adults over age 70 are most vulnerable to the effects of smoke inhalation.

Causes and symptoms

The harmful materials given off by combustion injure the airways and lungs in three ways: heat damage, tissue irritation, and oxygen starvation of tissues (asphyxiation). Signs of heat damage are singed nasal hairs, burns around and inside the nose and mouth, and internal swelling of the throat. Tissue irritation of the throat and lungs may appear as noisy breathing, coughing, hoarseness, black or gray spittle, and fluid in the lungs. Asphyxiation is apparent from shortness of breath and blue-gray or cherry-red skin color. In some cases, the person may not be conscious or breathing.

When to call the doctor

A doctor should be called whenever smoke is inhaled for more than a few minutes or whenever the inhaled smoke and fumes are known to contain toxic substances.

Diagnosis

In addition to looking for the signs of heat damage, tissue irritation, and asphyxiation, the physician will assess the individual's breathing by the respiratory rate (number of breaths per minute) and motion of the chest as the lungs inflate and deflate. The person's circulation is also evaluated by the pulse rate (number of heartbeats per minute) and blood pressure. Blood tests will indicate the levels of oxygen and byproducts of poisonous gases. Chest x rays are too insensitive to show damage to delicate respiratory tissues but can show fluid in the lungs (pulmonary edema).

The physician may perform a bronchoscopy, a visual examination in which the airways and lungs are seen through a fiber optic tube inserted down the person's windpipe (trachea). Other pulmonary function tests may be performed to measure how efficiently the lungs are working.

Treatment

Treatment varies with the severity of the damage caused. The primary focus of treatment is to maintain an open airway and provide an adequate level of oxygen. If the airway is open and stable, the individual may be given high-flow humidified 100 percent oxygen by mask. If swelling of the airway tissues is closing off the airway, the person may require the insertion of an endotracheal tube to artificially maintain an open airway.

Oxygen is often the only medication necessary. However, people who have a cough with wheezing (bronchospasm), indicating that the bronchial airways are narrowed or blocked, may be given a bronchodilator to relax the muscles and increase ventilation. There are also antidotes for specific poisonous gases in the blood; dosage is dependent upon the level indicated by blood tests. Antibiotics are not given until sputum and blood cultures confirm the presence of a bacterial infection.

In institutions where it is available, hyperbaric oxygen therapy may be used to treat smoke inhalation, resulting in severe carbon monoxide or cyanide poisoning . This treatment requires a special chamber in which the person receives pure oxygen at three times the normal atmospheric pressure, thus receiving more oxygen faster to overcome loss of consciousness, altered mental state, cardiovascular dysfunction, pulmonary edema, and severe neurological damage.

Botanical medicine can help to maintain open airways and heal damaged mucous membranes. It can also help support the entire respiratory system. Acupuncture and homeopathic treatment can provide support to the whole person who has suffered a traumatic injury such as smoke inhalation.

Prognosis

Although the outcome depends of the severity of the smoke inhalation and the severity of any accompanying burns or other injuries, with prompt medical treatment, the prognosis for recovery is good. However, some people may experience chronic pulmonary problems following smoke inhalation, and those with asthma or other chronic respiratory conditions prior to smoke inhalation may find their original conditions have been aggravated by the inhalation injury.

Prevention

Smoke inhalation is best avoided by preventing structural fires. Doing so involves inspection of wiring; safe use and storage of flammable liquids; and maintenance of clean, well-ventilated chimneys, wood stoves, and space heaters. Properly placed and working smoke detectors in combination with rapid evacuation plans minimize a person's exposure to smoke in the event of a fire. When escaping a burning building, a person should move close to the floor where there the air is cooler and clearer to breathe because hot air rises, carrying gases and particulate matter upward. Finally, firefighters should always wear proper protective gear.

Parental concerns

Parents should monitor their homes to make sure they provide a safe environment for everyone, including their children. They should also monitor play and recreational activities to limit exposure to smoke or toxic fumes. Parents should regularly check smoke detectors and change batteries every six months. In addition, families should have a fire escape plan, including a designated meeting area away from the house. This plan should be practiced periodically.

Resources

BOOKS

Beamis, John F., et al. Interventional Pulmonary Medicine. New York: Marcel Dekker, 2003.

Hanley, Michael E., and Carolyn H. Welsh. Current Diagnosis & Treatment in Pulmonary Medicine. New York: McGraw-Hill, 2003.

Piantadosi, Claude A. "Physical, Chemical, and Aspiration Injuries of the Lung." In Cecil Textbook of Medicine , 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 538–467.

Rodgers, George C., and Nancy J. Matyunas. "Toxic gases." In Nelson Textbook of Pediatrics , 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 2374.

Speizer, Frank E. "Environmental Lung Diseases." In Harrison's Principles of Internal Medicine , 15th ed. Edited by Eugene Braunwald et al. New York: McGraw-Hill, 2001, pp. 1467–74.

PERIODICALS

Stefanidou, M., and S. Athanaselis. "Toxicological aspects of fire." Veterinary and Human Toxicology 46, no. 4 (2004): 196–9.

ORGANIZATIONS

American Academy of Emergency Medicine. 611 East Wells St., Milwaukee, WI 53202. Web site: http://www.aaem.org/.

American College of Emergency Physicians. PO Box 619911, Dallas, TX 75261–9911. Web site: http://www.acep.org/.

American College of Occupational and Environmental Medicine. 55 West Seegers Rd., Arlington Heights, IL 60005. Web site: http://www.acoem.org/.

American College of Osteopathic Emergency Physicians. 142 E. Ontario St., Suite 550, Chicago, IL 60611. Web site: http://www.acoep.org/.

American College of Physicians. 190 N Independence Mall West, Philadelphia, PA 19106–1572. Web site: http://www.acponline.org/ .

American Lung Association. 1740 Broadway, New York, NY 10019. Web site: http://www.lungusa.org/diseases/lungtb.html.

American Thoracic Society. 1740 Broadway, New York, NY 10019. Web site: http://www.thoracic.org/.

WEB SITES

"Burns." Merck Manual. Available online at http://www.merck.com/mmhe/sec24/ch289/ch289a.html (accessed December 23, 2004).

Lafferty, Keith. "Smoke Inhalation." eMedicine , November 2,2004. Available online at http://www.emedicine.com/EMERG/topic538.htm (accessed December 23, 2004).

L. Fleming Fallon Jr., MD, DrPH

KEY TERMS

Asphyxiation —Oxygen starvation of tissues. Chemicals such as carbon monoxide prevent the blood from carrying sufficient oxygen to the brain and other organs. As a result, the person may lose consciousness, stop breathing, and die without artificial respiration (assisted breathing) and other means of elevating the blood oxygen level.

Hyperbaric oxygen therapy —Medical treatment in which oxygen is administered in specially designed chambers, under pressures greater than that of the atmosphere, in order to treat specific medical conditions, such as carbon monoxide poisoning, smoke inhalation, and certain bacterial infections.

Pulmonary —Referring to the lungs and respiratory system.

Pulmonary edema —An accumulation of fluid in the tissue of the lungs.