Choking, also known as foreign body airway obstruction (FBAO), is a phenomenon that occurs when breathing is impeded by a blockage inside of the respiratory tract. An obstruction that prevents oxygen from entering the lungs results in oxygen deprivation. Although oxygen stored in the blood and lungs can keep a person alive for several minutes after breathing stops, choking often leads to death.
Around 4,500 to 5,000 choking-related deaths occur in the United States every year. Deaths from choking most often occur in the very young (children under three years old) and in the elderly (adults over 75 years). Foods that can adapt their shape to that of the pharynx (such as bananas, marshmallows, or gelatinous candies) are more dangerous. Various forms of specific first aid are used to address and resolve choking.
Choking is the fourth leading cause of unintentional injury death in the United States. Many episodes go unreported because they are brief and resolve without needing medical attention. Of the reported events, 80% occur in people under 15 years of age, and 20% occur in people older than 15 years of age. Worldwide, choking on a foreign object resulted in 162,000 deaths (2.5 per 100,000) in 2013, compared with 140,000 deaths (2.9 per 100,000) in 1990.
Signs and symptoms Choking victims may present very subtly, especially in the setting of long term foreign body aspiration. Cough is seen in 80% of foreign body aspiration cases, and shortness of breath is seen in 25%. People may be unable to speak, attempt to use hand signals to indicate they are choking, attempt to force vomiting, or clutch at their throat.
History of episode An observed or recalled episode of choking, with sudden onset of any of the below respiratory and skin signs and symptoms while eating or handling small objects, is seen in around 90% of choking episodes. Initial episodes typically last seconds to several minutes, but can be followed by symptom improvement that can be mistaken as resolution.
Respiratory Initial respiratory symptoms can include involuntary cough, gurgling, gagging, shortness of breath, labored breathing, or wheezing. Children often present with excessive drooling and stridor (high pitched breathing sounds). Classic triad of choking symptoms in children is coughing, wheezing, and diminished breath sounds, however, a 10-year review showed that this grouping of symptoms was present together in only about 60% of patients.
Loss of consciousness may occur if breathing is not restored. In the setting of lower airway aspiration, patients may develop pneumonia like symptoms such as fever, chest pain, foul smelling sputum, or blood in sputum (hemoptysis). In the case of long term foreign body aspiration, patients may present with signs of lobar pneumonia or pleural effusion.
The time a choking victim is still alive without brain damage can vary, but typically brain damage can occur when the patient remains without air for approximately three minutes (it is variable). Death can occur if breathing is not restored in six to ten minutes (varies depending on the person). However, life can be extended by using cardiopulmonary resuscitation for unconscious victims of choking (see more details further below).
Skin The face could turn blue (cyanosis) from lack of oxygen if breathing is not restored. Cyanosis may also be seen on the fingertips. In a healthy child or adult, this sign is highly sensitive, but is only observed in 15-20% of choking episodes. Cyanosis is more readily apparent in people with lighter skin tones.
Causes
Choking occurs when a foreign body blocks the airway. This obstruction can be located in the pharynx, the larynx, trachea, or lower respiratory tract. The blockage can be either partial (insufficient air passes through to the lungs) or complete (complete blockage of airflow).
Foods that are small, round, or hard pose a high risk of choking. Examples include hard candy, chunks of cheese or hot dogs, nuts, grapes, marshmallows, and popcorn.
Among children, the most common causes of choking are food, coins, toys, and balloons. In one study, peanuts were the most common object found in the airway of children evaluated for suspected foreign body aspiration. Small, round non-food objects such as balls, marbles, toys, and toy parts are also associated with a high risk of choking death because of the potential to completely block a child's airway. Children younger than age three are especially at risk of choking due to lack of fully developed chewing habits, and the tendency to insert object in their mouth as they explore the environment. Because a child's airway is smaller in diameter than that of an adult's, smaller objects can more often cause airway obstruction in children. Additionally, infants and young children generate a less forceful cough than adults, so coughing may not be as effective in relieving airway obstruction.
Risk factors of foreign body airway obstruction for people of any age include the use of alcohol or sedatives, procedures involving the oral cavity or pharynx, oral appliances, or medical conditions that cause difficulty swallowing or impair the cough reflex. Conditions that can cause difficulty swallowing and/or impaired coughing include neurological conditions such as stroke, Alzheimer's disease, or Parkinson's disease. In older adults, risk factors also include living alone, wearing dentures, and having difficulty swallowing. Children and adults with neurological, cognitive, or psychiatric disorders are at an increased risk of choking and may experience a delay in diagnosis because there may not be a known history of a foreign body entering the airway.
Choking on food is only one type of airway obstruction; others include blockage due to tumors, swelling and inflammation of the airway tissues (from organic foreign bodies or another reason), and compression of the laryngopharynx, larynx, or vertebrate trachea in strangulation. Foreign bodies can also enter the reparatory tract through the chest wall, such as in the setting of a gunshot injury.
Diagnosis Recognition and diagnosis of choking primarily involves identification of the signs and symptoms like coughing and wheezing (see Signs and Symptoms). Immediate recognition of the symptoms is important, but based on the short length of some episodes, diagnosis during the first 24 hours only occurs in 50–60% of cases.
After the initial episode, choking can lead to an obstruction of the airway that prompts further diagnostic steps. For choking episodes that require emergent evaluation by a doctor, several tools can be used for diagnosis, each with their advantages and drawbacks.
Imaging and visualization methods
Bronchoscopy According to the American Heart Association, bronchoscopy is a reliable method used to visualize the cause of choking when not resolved via oxygen and supportive care. Bronchoscopy also is a crucial tool in foreign body removal after supportive care has been provided and the person who is choking is stable. However, bronchoscopy is an invasive form of imaging and intervention in comparison to the below diagnostic tools, and requires sedation to perform. X-ray An X-ray uses high-frequency electromagnetic radiation to visualize the human body. In the case of choking, a chest X-ray is obtained to visualize the lungs and upper airway. However, many objects do not show up on X-ray (radiolucent). About 10% objects are radio-opaque and can be visualized using X-ray. X-rays are more accessible than other imaging modalities but expose a person to radiation. In cases where X-ray is inconclusive, fluoroscopy may be able to demonstrate radiolucent or smaller foreign bodies. Chest fluoroscopy is a real-time X-ray image (sometimes referred to as an X-ray movie) to view breathing and coughing. Computerized tomography (CT) A CT scan uses a tube with multiple X-ray machines to build a 3D image from 2D X-ray images of multiple cross-sections. Radiolucent objects can be better captured on CT than X-ray. Additionally, modern imaging analysis software allows for airway reconstruction following a chest CT, creating a model of the airway network in the lungs that can better visualize the exast location of a foreign body. Since a CT is multiple X-rays, the exposure to radiation is significantly greater. Magnetic resonance imaging (MRI) An MRI scan uses radio-frequency pulse under a magnetic field to create a high-resolution image of the body. MRIs can detect foreign bodies with higher accuracy than X-ray or CT. MRI does not expose the person to radiation. Drawbacks of MRI include claustrophobia and high cost. For children, sedation may be required to undergo MRI imaging, which is an increased risk when the airway is already potentially compromised.
Treatment Airway management is used to restore a person's ventilation which consists of severity assessment, procedural planning, and may consist of multiple treatment modalities to restore airway.
Treatments will vary based on severity and stage of airway blockage. In basic airway management, treatment generally consists of anti-choking first aid techniques, such as the Heimlich maneuver. In advanced airway management, complex clinical methods are used.
Basic treatment (first aid) Basic treatment of choking includes several non-invasive techniques to help remove foreign bodies from the airways.
General strategy: "five and five" For a conscious choking victim, most institutions such as the American Heart Association, the American Red Cross and the NHS, recommend the same general protocol of first-aid: encouraging the victim to cough, followed by hard back slaps (as described below). If these attempts are not effective, the procedure continues with abdominal thrusts (the Heimlich maneuver) or chest thrusts if the victim cannot receive abdominal pressure (as described below).
If none of these techniques are effective, protocol by various institutions recommend alternating the series of back slaps and series of thrusts (these on the abdomen or chest, depending on the victim), 5 times of each technique and repeat ("five and five").
This procedure has modifications for infants (babies under 1 year-old), for the people with problems in the belly as the pregnant or extremely obese people, for the disabled victims in wheelchair, for the victims that lay on the bed but are unable to sit up, and for the victims that lay on the floor but are unable to sit up.
In scenarios when the first aid procedures are not resolving the choking, it is necessary to call to emergency medical services, but administration of first aid should be continued until they arrive.
Each one of the techniques in the first aid protocol against choking are detailed below:
Cough If the choking victim is conscious and can cough, the American Red Cross and the Mayo Clinic recommend encouraging them to stay calm and continue coughing freely.
Back blows (back slaps) Many associations, including the American Red Cross and the Mayo Clinic, recommend the use of back blows (back slaps) to aid a choking victim. This technique is performed by bending the choking victim forward as much as possible, even trying to place their head lower than the chest, to avoid the blows driving the object deeper into the person's throat (a rare complication, but possible). The bending is in the back, while the neck should not be excessively bent. It is convenient that one hand supports the victim's chest. Then the back blows are performed by delivering forceful slaps with the heel of the other hand on the victim's back, between the shoulder blades.
The back slaps push behind the blockage to expel the foreign object out. In some cases, the physical vibration of the action may cause enough movement to clear the airway.
Abdominal thrusts (Heimlich maneuver)