Smoke Inhalation Overview
The number one cause of death related to fires is smoke inhalation.
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.
When to Seek Medical Care
Everyone who has suffered from smoke inhalation needs to have their “A.B.C’s” checked. That is Airway, Breathing, and Circulation. Call your doctor or go to your local emergency department for advice. If you have no signs or symptoms, home observation may be recommended.
Call 911 if you experience the following symptoms with smoke inhalation:
- Hoarse voice
- Difficulty breathing
- Drawn out coughing spells
- Mental confusion
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.
Exams and Tests
A number of tests and procedures may be done. Which tests depends on the severity of the signs and symptoms.
- Chest X-ray: Respiratory complaints such as persistent cough and shortness of breath, indicate the need for a chest X-ray. The initial X-ray may be normal despite significant signs and symptoms. A repeat X-ray may be needed during the observation period to determine if there is delayed lung injury.
- Pulse oximetry: A light probe is attached typically to the finger, toe, or earlobe to determine the degree of oxygen in the person's blood. Pulse oximetry has limitations. Low blood pressure, for instance, can make it inaccurate if not enough blood is getting to the parts of the body where the probe is attached.
- Blood tests
- Complete blood count: This test determines whether there are enough red blood cells to carry oxygen, enough white blood cells to fight infection, and enough platelets to ensure clotting.
- Chemistries (also called basic metabolic profile): Serum electrolytes (sodium, potassium, and chloride) can 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 tells you the blood pH and can help the doctor decide the degree of oxygen shortage.
- Carboxyhemoglobin and methemoglobin levels: This level should be obtained 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.
Smoke Inhalation Treatment
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.
Medical Treatment
A number of treatments may be given for smoke inhalation.
- Oxygen: Oxygen is the mainstay of treatment. It may be applied with a nose tube or mask or through a tube put down the throat. If there are signs of upper airway problems, for example hoarseness, the person may need to be intubated. To do this, the doctor places a tube down the person's throat to keep the airway from closing due to swelling. If there is respiratory distress or mental status changes, the person may be intubated to let the staff help with breathing, to suction off mucus, and keep the person from breathing the contents of their own stomach.
- Bronchoscopy: Bronchoscopy is a procedure done to look at the degree of damage to the airways through a small scope and to allow suctioning of secretions and debris. Usually it's done through an endotracheal tube (a thin tube with a camera attached) after the person has been given sedation and pain relievers. The procedure may be needed if there is growing respiratory failure, failure to demonstrate clinical improvement, or a segment of the lung remains collapsed.
- Hyperbaric oxygenation (HBO): If the person has carbon monoxide poisoning, hyperbaric oxygenation may be considered. Hyperbaric oxygenation is a treatment in which the person is given oxygen in a compression chamber. Some studies have shown that hyperbaric oxygenation causes a reduction in symptoms of the nervous system. In cases of 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 person is hospitalized.
Next Steps
Follow-up
Once the person leaves the hospital, follow-up care is typically arranged. If the condition worsens or doesn't improve the way it is expected to after discharge, the person should return immediately to the emergency department.
Medications such as various inhalers and pain medications may be prescribed. There may still be 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. It's important to avoid triggering factors such as cigarette smoke.
Persistent hoarseness 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, behaviorally or both, could lead to an improved voice.
Prevention
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 an occupied building. This should ensure early detection of smoke and allow time for evacuation.
- Carbon monoxide detectors should be placed in locations at risk for carbon monoxide exposure (such as near furnaces or garages).
- Escape routes and plans for how to escape should be worked out before there is a fire and reviewed periodically.
- Numbers for the police, fire department, and the local poison control center should be kept in a visible place for an emergency. Find the poison control center now by checking the web site of the American Association of Poison Control Centers.
Multimedia
Media file 1: A smoke inhalation victim. Note the soot in the nostrils and the degree of swelling of the face. His voice was hoarse upon arrival. He had an endotracheal intubation performed (a tube was placed in their airway to help him breathe) because of concern of significant airway edema (swelling) and potential for airway obstruction.
Media type: Photo
Media file 2: State-of-the-art hyperbaric oxygen chamber by HyperTec.
Media type: Photo
Media file 3: State-of-the-art single person chamber by HyperTec.
Media type: Photo