The smoke released by any type of fire (forest, brush, crop, structure, tires, waste or wood burning) is a mixture of particles and chemicals produced by incomplete burning of carbon-containing materials. All smoke contains carbon monoxide, carbon dioxide and particulate matter (PM or soot). Smoke can contain many different chemicals, including aldehydes, acid gases, sulfur dioxide, nitrogen oxides, polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, styrene, metals and dioxins. The type and amount of particles and chemicals in smoke varies depending on what is burning, how much oxygen is available, and the burn temperature.
Exposure to high levels of smoke should be avoided. Individuals are advised to limit their physical exertion if exposure to high levels of smoke cannot be avoided. Individuals with cardiovascular or respiratory conditions (e.g., asthma), fetuses, infants, young children, and the elderly may be more vulnerable to the health effects of smoke exposure.
Inhaling smoke for a short time can cause immediate (acute) effects. Smoke is irritating to the eyes, nose, and throat, and its odor may be nauseating. Studies have shown that some people exposed to heavy smoke have temporary changes in lung function, which makes breathing more difficult. Two of the major agents in smoke that can cause health effects are carbon monoxide gas and very small particles (fine particles, or PM2.5 ). These particles are two and one half (2.5) microns or less in size (25,400 microns equal an inch) and individual particles are too small to be seen with the naked eye.
Inhaling carbon monoxide decreases the body’s oxygen supply. This can cause headaches, reduce alertness, and aggravate a heart condition known as angina. Fine particles are able to travel deeply into the respiratory tract, reaching the lungs. Inhaling fine particles can cause a variety of health effects, including respiratory irritation and shortness of breath, and can worsen medical conditions such as asthma and heart disease. During increased physical exertion, cardiovascular effects can be worsened by exposure to carbon monoxide and particulate matter. Once exposure stops, symptoms from inhaling carbon monoxide or fine particles generally diminish, but may last for a couple of days.
Avoiding smoky situations is the best way to avoid exposure. If your age or health status places you at greater risk from smoke exposure you should speak with your doctor about alternative steps you can take when encountering smoky situations. Anyone with persisting or frequent symptoms that they think are associated with smoke exposure should see their health care provider. Additional information on carbon monoxide and fine particles can be found at the web addresses listed at the end of this fact sheet.
There is also the potential for chronic health effects from exposure to the components of smoke. Long term exposure to ambient air containing fine particles has been associated with increases in cardiovascular disease and mortality in populations living in areas with higher fine particulate air pollution. Frequent exposure to smoke for brief periods may also cause long-term health effects. Firefighters, who are exposed frequently to smoke, have been examined for long-term health effects (for example, cancer, lung disease, and cardiovascular disease) of repeated smoke exposures. The findings from these studies are not consistent or conclusive. Some studies show an increased frequency of these diseases among firefighters compared to similar male reference populations (e.g., male policemen, white males in the general population), while others do not.
The number one cause of death related to fires is smoke inhalation. An estimated 50-80% 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 damages the body by simple asphyxiation (lack of oxygen), chemical irritation, chemical asphyxiation, or a combination of these.
- Simple asphyxiants
- Combustion can simply use up the oxygen near the fire and lead to death when there is no oxygen for a person to breathe.
- Smoke itself can contain products that do not cause direct harm to a person, but they take up the space that is needed for oxygen. Carbon dioxide acts in this way.
- Irritant compounds
- Combustion can result in the formation of chemicals that cause direct injury when they contact the 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.
- Chemical asphyxiants
- A fire can produce compounds that do damage by interfering with the 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 during the production of energy.
- If either the delivery of oxygen or the use of oxygen is inhibited, cells will die.
- Carbon monoxide poisoning 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 the airway passages or changes in skin color may be useful in determining the degree of injury.
- When the mucous membranes of the respiratory tract get irritated, they secrete more mucus.
- Bronchospasm and increased mucus production 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 delivery to the blood, the decreased ability of blood to carry oxygen because of chemicals in smoke, or the inability of the body’s cells to use oxygen.
- The patient may have rapid breathing as they attempt to compensate for these injuries.
- Hoarseness or noisy breathing
- This may be a sign that fluids are collecting in the upper airway and may cause a blockage.
- Irritant chemicals may cause vocal cord spasm, swelling, and constriction of the upper airways.
- Eyes: Eyes may be red and irritated by the smoke, and there may be burns on the corneas in the eyes.
- Skin color: Skin color may range from pale to bluish to cherry red.
- Soot in the nostrils or throat may give a clue as to the degree of smoke inhalation.
- The nostrils and nasal passages may be swollen.
- In all fires, people are exposed to various quantities of carbon monoxide.
- The patient may have no respiratory problems, but may still have inhaled carbon monoxide.
- Headache, nausea, confusion and vomiting are 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.
When To Seek Immediate Care.
If the smoke inhalation victim has no signs or symptoms, home observation may be appropriate. If in doubt, call the doctor or go to the local emergency department for advice.
Seek medical attention if the patient experiences the following symptoms with smoke inhalation:
- Hoarse voice
- Difficulty breathing
- Prolonged coughing spells
- Mental confusion
Decide whether to call an ambulance for assistance.
- Someone with smoke inhalation can get worse quickly.
- If such a person were transported by private vehicle, significant injury or death could occur on the way that could have been avoided if that person were transported by emergency medical services.
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Exams & X-Rays
A number of tests and procedures may be performed. Which tests are performed depends on the severity of the signs and symptoms and is at the discretion of the doctor.
- Chest X-ray
- If the patient has respiratory complaints such as persistent cough and shortness of breath, a chest X-ray should be done.
- The initial chest X-ray may be normal despite significant signs and symptoms.
- A repeat chest X-ray may be necessary during the observation period to determine if delayed lung injury is occurring.
- Pulse oximetry
- A light probe is typically attached to the finger, toe, or earlobe, to determine the amount of oxygen in the blood.
- Pulse oximetry may be inaccurate if the patient has low blood pressure, and enough blood is not getting to parts of the body where the probe is attached.
- Blood tests
- Complete blood count: This test is done to determine if there are enough red blood cells to carry oxygen, enough white blood cells to fight infection, and enough platelets to ensure clotting can occur.
- Chemistries (also called basic metabolic profile): This test reveals any changes of pH in the blood that may happen because of interference with oxygen diffusion, transport, or use. Serum electrolytes (sodium, potassium, and chloride) can also be monitored. Renal (kidney) function tests (creatinine and blood urea nitrogen) are also monitored.
- Arterial blood gas: For people with significant respiratory distress, acute mental status changes, or shock, an arterial blood gas may be obtained. This test may help the doctor to determine the degree of oxygen shortage.
- Carboxyhemoglobin and methemoglobin levels: These levels should be measured in all smoke inhalation victims with respiratory distress, altered mental status, low blood pressure, seizures, fainting, and blood pH changes. It is now routinely done in many hospitals whenever arterial blood gas is assessed.
Self Care At Home
Remove the person with smoke inhalation from the scene to a location with clean air.
Make sure that you are not putting yourself in danger before you attempt to pull someone from a smoke-filled environment. If you would be taking a serious risk to help the person, wait for trained professionals to arrive at the scene.
If necessary, CPR should be initiated by trained bystanders until emergency medical help arrives.
A number of treatments may be given for smoke inhalation.
- Oxygen is the mainstay of treatment.
- Oxygen may be applied with a nose tube, mask, or through a tube down the throat.
- If the patient has signs and symptoms of upper airway problems (hoarseness), they will most likely be intubated. The doctor places a tube down the throat to keep the airway from closing due to swelling.
- If the patient has respiratory distress or mental status changes, they may also be intubated to enable the staff help with breathing, to suction mucus, and keep the patient from choking on secretions.
- Bronchoscopy is procedure performed through a small scope to directly look at the degree of damage done to the airways and to allow for suctioning of secretions and debris.
- Usually bronchoscopy is done through an endotracheal tube after the patient receives adequate sedation and pain relievers.
- Bronchoscopy may be necessary if the patient has increasing respiratory failure, fails to demonstrate clinical improvement, or a segment of the lung remains collapsed.
- Hyperbaric oxygenation (HBO)
- If the patient has carbon monoxide poisoning, hyperbaric oxygenation may be considered.
- Hyperbaric oxygenation is a treatment in which the patient is given oxygen in a compression chamber.
- Some studies have demonstrated that hyperbaric oxygenation causes a reduction in symptoms of the nervous system, and if the patient has carbon monoxide poisoning, it may make recovery quicker.
- The indications for and availability of this treatment vary depending on the institution and the region in which the patient is hospitalized.
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Once the patient leaves the hospital, follow-up care is typically arranged. The patient should return immediately to the emergency department if they feel that their condition is worsening after discharge from the hospital.
- Medications may be prescribed, such as various inhalers and pain medications.
- The patient may notice shortness of breath with minimal exertion.
- It may take time for the lungs to fully heal, and some people may have scarring and shortness of breath for the rest of their lives. Avoid triggering factors, such as cigarette smoke.
- Persistent hoarseness of the voice may occur in people who have sustained burn or smoke inhalation injuries or both. Early attention to these problems, many of which are treatable surgically or behaviorally or both, could lead to an improved voice.
Prevention is key when discussing smoke inhalation. Numerous prevention strategies can be employed to avoid exposure to smoke.
- Smoke detectors should be placed in every room of occupied buildings. This should ensure early detection of smoke to allow plenty of time for evacuation.
- Carbon monoxide detectors should be placed in locations at risk for carbon monoxide exposure (such as from malfunctioning furnaces, gas water heaters, kerosene space heaters, propane heaters and stoves, gasoline or diesel generators, and boats with a gasoline engine).
- Escape routes and plans for how to escape should be worked out prior to the onset of a fire and reviewed often.
- Numbers for the police, fire department, and your local poison control center should be kept in a visible place in the event of an emergency. Find your poison control center now by checking the Web site of the American Association ofPoison Control Centers.
This concludes our four part blog on Smoke Inhalation. For more, visit our website at Biowashing.com