Foreign Body Aspiration

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Background

Foreign body aspiration can be a life-threatening emergency. An aspirated solid or semisolid object may lodge in the larynx or trachea. If the object is large enough to cause nearly complete obstruction of the airway, asphyxia may rapidly cause death. Lesser degrees of obstruction or passage of the obstructive object beyond the carina can result in less severe signs and symptoms.

Chronic debilitating symptoms with recurrent infections might occur with delayed extraction, or the patient may remain asymptomatic. The actual aspiration event can usually be identified, although it is often not immediately appreciated. The aspirated object might even escape detection. Most often, the aspirated object is food, but a broad spectrum of aspirated items has been documented over the years. Commonly retrieved objects include seeds, nuts, bone fragments, nails, small toys, coins, pins, medical instrument fragments, and dental appliances.

Geographic differences in the spectrum of objects commonly found in a particular environment and variations in dietary and eating habits affect the relative frequency with which various objects are aspirated.

The Medscape Reference article Airway Foreign Body Imaging may be helpful.

Pathophysiology

Near-total obstruction of the larynx or trachea can cause immediate asphyxia and death. Should the object pass beyond the carina, its location would depend on the patient's age and physical position at the time of the aspiration. Because the angles made by the mainstem bronchi with the trachea are identical until age 15 years, foreign bodies are found on either side with equal frequency in persons in this age group.[1] With normal growth and development, the adult right and left mainstem bronchi diverge from the trachea with very different angles, with the right mainstem bronchus being more acute and therefore making a relatively straight path from larynx to bronchus. Objects that descend beyond the trachea are more often found in the right endobronchial tree than in the left.

In the series reported by Debeljak et al,[2] 42 foreign bodies were in the right endobronchial tree, 20 were in the left, and 1 was in the trachea. Once aspirated, objects may subsequently change position or migrate distally, particularly after unsuccessful attempts to remove the object or if the object fragments. The object itself might cause obstruction. Vegetable material may swell over hours or days, worsening the obstruction. Cough, wheeze, stridor, dyspnea, cyanosis, and even asphyxia might ensue. Organic foreign bodies, such as oily nuts (commonly peanuts), induce inflammation and edema.

Local inflammation, edema, cellular infiltration, ulceration, and granulation tissue formation may contribute to airway obstruction while making bronchoscopic identification and removal of the object more difficult. The airway becomes more likely to bleed with manipulation; the object is more likely to be obscured and becomes more difficult to dislodge. Mediastinitis or tracheoesophageal fistulas may result. Distal to the obstruction, air trapping may occur, leading to local emphysema, atelectasis, hypoxic vasoconstriction, postobstructive pneumonia, and the possibility of volume loss, necrotizing pneumonia or abscess, suppurative pneumonia, or bronchiectasis.

Bronchoscopically, the object may appear as a tumor. Even if the object is removed, the inflammatory changes may not be completely reversible. Some investigators believe scar carcinoma may develop over time. The likelihood of complications increases after 24-48 hours, making expeditious removal of the foreign body imperative.

Epidemiology

Frequency

International

Most of the literature relates to statistics, diagnosis, and treatment in children younger than 16 years. Literature on foreign body aspiration in adults is limited. Local environments have an important influence on the types of objects aspirated, location in the tracheobronchial tree, and prognosis.

Geographic differences in the spectrum of objects commonly found in a particular environment and variations in dietary and eating habits affect the relative frequency with which various objects are aspirated. The heterogeneity of the populations studied, materials in the environment, and the availability of medical technology influence the reported incidence and prognosis.

Many aspirated foreign bodies are unexpectedly discovered, go undetected, or are misdiagnosed. The often-fatal syndrome of acute asphyxiation from upper airway obstruction associated with eating, known as the café coronary,[3] and aspiration of gastric contents are usually not considered with other foreign body aspiration syndromes. For these reasons, the true incidence and prevalence of foreign body aspiration is unknown.

Mortality/Morbidity

According to the National Safety Council, choking remained the fourth leading cause of unintentional injury death in the United States as of 2004. In 2006, a total of 4,100 deaths (1.4 deaths per 100,000 population) from unintentional ingestion or inhalation of food or other objects resulting in airway obstruction was reported.[4] The incidence rate was 0.5 deaths per 100,000 population aged 0-4 years. It was lower for adolescents and young adults. The incidence rate then increased steadily with age beginning in the sixth decade (2.6 deaths per 100,000 population aged 65-75 y) and rose rapidly after age 70 years (13.6 deaths per 100,000 population older than 75 y).

The overall risk of death from the café coronary is estimated to be 0.66 deaths per 100,000 people. Even if the patient does not die, symptoms often develop immediately. Morbidity increases if extraction of the object is delayed beyond 24 hours.

Sex

The male-to-female ratio is 2:1, depending on the study.

Age

Children, especially those aged 1-3 years, are at risk for foreign body aspiration because of their tendency to put everything in their mouths and because of the way they chew. Young children chew their food incompletely with incisors before their molars erupt. Objects or fragments may be propelled posteriorly, triggering a reflex inhalation.

Adults who (1) undergo oropharyngeal procedures, (2) have various oral appliances, (3) become intoxicated, (4) receive sedatives, or (5) may have neurological or psychiatric disorders are at increased risk of aspirating foreign bodies.

Because young children and older persons with neurological, cognitive, or psychiatric disorders might not be able to provide their history, diagnosis may be delayed. In Limper and Prakash's 1990 study,[5] the median age for adults (ie, patients >16 y) with foreign body aspirations was 60 years, with an age range of 18-88 years. Numerous studies concur that children younger than 16 years account for most cases of foreign body aspiration.

History

In the café coronary syndrome, a large object (often poorly chewed meat) lodges in the larynx or trachea, causing nearly complete airway obstruction. Respiratory distress, aphonia, cyanosis, loss of consciousness, and death occur in quick succession unless the object is dislodged. When the degree of obstruction is less severe or when the aspirated object descends beyond the carina, the presentation is less dramatic. Sudden onset of the classic triad (ie, coughing, wheezing, decreased breathing sounds) is frequently not observed.

Presenting symptoms (other than cough) include fever, hemoptysis, dyspnea, and chest pain. A history of a choking episode is not always obtained or may have initially been ignored or misdiagnosed. Most patients or parents can identify a specific episode of choking; however, presentation is often delayed by more than a week. The latency period prior to the onset of symptoms may last months or years if the foreign body is inert bone or inorganic material.

Patients may have been empirically treated for other conditions, even when a choking episode was witnessed. Patients with chronic symptoms may have been erroneously diagnosed as having asthma or chronic bronchitis. Young children and patients with neurologic or psychiatric disorders are at increased risk for aspiration but might not be able to describe symptoms or to report choking episodes.

Other risk factors include institutionalization, old age, poor dentition, and alcohol or sedative use. A presentation of cyanosis, cough, wheeze, incompletely resolved pneumonia, or localized bronchiectasis should raise suspicion of foreign body aspiration, particularly in individuals at risk for foreign body aspiration. Seek information about a history of impaired swallowing, impaired coughing, traumatic loss of consciousness, intoxication, or oropharyngeal surgery.

Physical

A small number of foreign body aspirations are incidentally found after chest radiography or bronchoscopic inspection. Patients may be asymptomatic or may be undergoing testing for other diagnoses. If present, physical findings may include stridor, fixed wheeze, localized wheeze, or diminished breath sounds. If obstruction is severe, cyanosis may occur. Signs of consolidation can accompany postobstructive pneumonia.

Causes

Children are at risk for putting small toys, candies, or nuts into their mouths. Children aged 1-3 years chew incompletely with incisors before their molars erupt, and objects or fragments may be propelled posteriorly, triggering a reflex inhalation.

Among adults, the following conditions, actions, and procedures facilitate foreign body aspiration:

Frequently aspirated objects include food (especially nuts and seeds), teeth, dental appliances, and medical instruments. The original event might have been forgotten. Choking with severe dyspnea, leading to respiratory or cardiac arrest while eating, might be initially misdiagnosed as myocardial ischemia.

Laboratory Studies

Arterial blood gas analysis is useful for judging the adequacy of ventilation and identifying the evolution of acute ventilatory failure. Administer the test in conjunction with an assessment of appearance, voice, speech, vital signs, physical examination, and pulse oximetry.

Imaging Studies

Perform standard posteroanterior inspiratory chest radiography to look for unilateral hyperinflation, lobar or segmental atelectasis, mediastinal shift, or pneumomediastinum. Most foreign bodies are radiolucent. Less than 20% of aspirated foreign bodies are radiopaque. The sensitivity for detecting signs of foreign body aspiration improves over time. On chest radiographs, children have air trapping more often, while adults have atelectasis more often. The proportion of patients with foreign body aspiration who have normal findings on chest radiographs varies widely in the literature, and atelectasis or consolidation is often not appreciated for at least 24 hours. If foreign body aspiration is suspected, a normal finding on chest radiographs does not exclude the diagnosis.

Expiratory chest radiographs are more sensitive for air trapping than inspiratory chest radiographs. Signs are enhanced lucency and relatively low diaphragm position. If the patient cannot cooperate, lateral decubitus views may demonstrate air trapping in the dependent lung.[6]

CT scanning of the chest may show the object or may identify localized air trapping.[7] The presence of a foreign body and its condition, anatomic location (ie, larynx, trachea, main, lobar or segmental bronchus), shape, composition, position, size (ie, number of fragments), and extent of entrapment by edema or granulation tissue must be identified prior to attempts at extraction. The foreign body may be missed if it is of a color that would camouflage it from the surrounding mucosa (eg, carrot, rubber pencil eraser) or if it is completely engulfed by granulation tissue. The object also may not be visualized if it is too distal. Straight pins can migrate into deep segmental bronchi beyond the visual range of even a flexible bronchoscope.

CT scanning supplemented with virtual bronchoscopic imaging[8, 9, 10] may further provide such useful information prior to an attempt at bronchoscopy, especially when attempting to pass a flexible bronchoscope beyond the first object encountered is not an advisable course of action. Whether virtual bronchoscopy can adequately replace early bronchoscopic inspection when other evidence to support a suspicion of foreign body aspiration is not yet manifest remains undetermined. Virtual bronchoscopy is not yet widely available.

Fluoroscopy of the chest can be performed to observe diaphragmatic and mediastinal shifting of air trapping while the patient is breathing if the diagnosis is in doubt or if the patient cannot cooperate.

Radioisotope lung perfusion scanning may demonstrate perfusion defects due to hypoxic vasoconstriction in poorly ventilated regions, even when physical examination and radiography findings are minimal.

Other Tests

Bronchoscopy (both rigid and flexible) can be both diagnostic and therapeutic.

Procedures

See Bronchoscopy in Medical care.

Histologic Findings

Organic foreign bodies such as oily nuts (commonly peanuts) induce inflammation and edema. Local inflammation, edema, cellular infiltration, ulceration, and granulation tissue formation may contribute to airway obstruction while making bronchoscopic identification and removal of the object more difficult. Mediastinitis or tracheoesophageal fistulas might result. Distal to the obstruction, air trapping might lead to local emphysema, atelectasis, hypoxic vasoconstriction, suppurative pneumonia, or bronchiectasis. Bronchoscopically, the object may appear as a tumor, and scar carcinoma may develop over time. Even if the object is removed, the inflammatory changes may not be completely reversible.

Medical Care

Acute choking, with respiratory failure associated with tracheal or laryngeal foreign body obstruction, may be successfully treated at the scene with the Heimlich maneuver, back blows, and abdominal thrusts. Even in nonemergency situations, expeditious removal of tracheobronchial foreign bodies is recommended.

Bronchoscopy can be used diagnostically and therapeutically. Most aspirated foreign bodies are radiolucent. Radiologic procedures do not have extreme diagnostic accuracy, and aspiration events are not always detected. Other medical conditions are possible. The presentation may be delayed, and the patient may have been unsuccessfully treated for other conditions.

The presence of a foreign body and its condition, anatomic location (eg, larynx; trachea; main, lobar, or segmental bronchus), shape, composition, position, and extent of entrapment by edema or granulation tissue must be identified prior to extraction attempts. If the foreign body is of a color that might camouflage it within the surrounding mucosa (eg, carrot, rubber pencil eraser) or if the object is completely engulfed by granulation tissue, it may be missed. If it is too distal, the object may not be visualized.

Straight pins (typically aspirated by tailors and seamstresses) can migrate into deep segmental bronchi beyond the visual range of even a flexible bronchoscope.

Rigid bronchoscopy

Rigid bronchoscopy usually requires heavy intravenous sedation or general anesthesia. The rigid bronchoscope has important advantages over the flexible bronchoscope. The larger diameter of the rigid bronchoscope facilitates the passage of various grasping devices, including a flexible bronchoscope. A better chance of quick, successful extraction and better capabilities of suctioning clotted blood and thick secretions are offered by the rigid bronchoscope. The pediatric flexible bronchoscope lacks a hollow working channel through which instruments may be inserted or blood and secretions may be aspirated.

Unlike the flexible bronchoscope, the patient can be ventilated through the rigid scope; therefore, ventilation of the patient can be maintained. Rigid bronchoscopy is the procedure of choice for removing foreign bodies in children and in most adults. Success rates for extracting foreign bodies are reportedly more than 98%. Large solid and semisolid objects are best managed emergently in the operating room with a rigid bronchoscope and appropriate grasping instruments.

Whichever type of bronchoscope is used, practice grasping and manipulating a similar object outside of the body to help reduce the likelihood of shattering the object or of impacting the object to an even less favorable position.

Flexible bronchoscopy

The flexible fiberoptic bronchoscope can be directly inserted into the trachea transnasally or transorally. It can also be inserted into the trachea through a rigid bronchoscope or through a large endotracheal tube. Sedatives can be administered if needed. Small forceps, baskets, and Fogarty balloon catheters can be inserted through the narrow working channel. The instrument offers a limited capability to visualize, grasp, and remove certain foreign bodies of appropriate size, shape, and position. As with rigid bronchoscopy, it is imperative to practice grasping an identical object outside of the body before attempting to manipulate the aspirated object.

While passing the flexible bronchoscope through the larynx via the transnasal route is easier than the transoral route, the latter is preferable if removal of the foreign body is anticipated. Aspirated foreign bodies are too large or rigid to be withdrawn through the flexible bronchoscope and often also cannot be withdrawn through an endotracheal tube. Withdrawal of an exposed foreign body poses the risks of trauma and impaction in the trachea, larynx, or pharynx. Any attempt to withdraw the bronchoscope from the nose with an exposed foreign body tenuously grasped at its tip poses the additional risk of trauma and impaction in the nasal passage.

Despite its limitations, use of the flexible fiberoptic bronchoscope may be necessary in patients with maxillofacial or cervical trauma in whom rigid bronchoscopy is not feasible.

Flexible bronchoscopy can be performed to confirm, localize, and visualize the foreign body in the tracheobronchial tree. The flexible bronchoscope can provide access to subsegmental bronchi beyond that provided by the rigid bronchoscope. If gas exchange is already compromised or if insertion of the flexible bronchoscope would result in significant impairment of gas exchange, flexible bronchoscopy is contraindicated. Diagnostic flexible bronchoscopy prior to rigid bronchoscopy has even been advocated for nonasphyxiating children in whom the diagnosis of foreign body aspiration cannot be confirmed.

Limit use of the flexible bronchoscope for extracting foreign bodies to adult patients who aspirated objects too small to cause total airway obstruction but that can be grasped securely without shattering. Practicing grasping and manipulating a similar object is necessary to avoid shattering or impacting the object in an even less favorable location. The limited ability to achieve and maintain adequate grasp of the intact foreign body makes extraction via flexible bronchoscopy more time consuming and less reliable than via rigid bronchoscopy.

For the same reasons, flexible bronchoscopy also exposes the patient to a greater risk of bleeding, perforation, shattering of the object, and losing the object in the subglottic area or more distal bronchus. With flexible bronchoscopy, the potential exists for a more difficult subsequent extraction, worse airway obstruction, or even asphyxiation.

Whichever technique is used, it is essential to determine that all of the foreign body has been extracted. Objects not successfully removed may fragment and become impacted in bronchi that are more distal. Carefully examine the extracted object for integrity. Inspect the tracheobronchial tree for fragments or other unsuspected foreign bodies.

Inhalation of a bronchodilator followed by postural drainage with chest therapy may be useful in a minority of asymptomatic adult patients and may obviate the need for bronchoscopy. To avoid increasing morbidity, this conservative measure should not delay bronchoscopic extraction by more than 24 hours. If the object is not intact, if multiple foreign body aspiration is suspected, or if concern exists about airway injury, bronchoscopic inspection may still be necessary.

Surgical Care

Almost all aspirated foreign bodies can be extracted bronchoscopically. If rigid bronchoscopy is unsuccessful, surgical bronchotomy or segmental resection may be necessary. Chronic bronchial obstruction with bronchiectasis and destruction of lung parenchyma may require segmental or lobar resection.

Consultations

A pulmonologist or thoracic surgeon with experience in foreign body extraction should immediately perform bronchoscopic inspection and extraction of the object.

An anesthesiologist may be needed to maintain adequate ventilation and control of the upper airway during diagnostic and therapeutic procedures. Rigid bronchoscopy is performed with the patient under general anesthesia or heavy sedation.

An otolaryngologist can evaluate the pharynx and larynx for the presence of a retained foreign body or signs of injury from either aspiration or extraction of the foreign body. If necessary, the otolaryngologist can perform tracheostomy to maintain airway patency.

A speech pathologist can perform a formal swallowing evaluation and prescribe prophylactic measures for patients at risk for foreign body aspiration (eg, patients with potential for impaired swallow reflex).

Diet

In order to prevent food aspiration, the diet should be appropriate for the patient's ability to chew and swallow. The size and shape of food bits should be appropriate for the patient's age and the size of the larynx and tracheobronchial tree.

Activity

Speaking while eating increases the likelihood of food aspiration. Impaired consciousness also increases the likelihood of aspiration while eating.

Further Inpatient Care

If the foreign body is quickly and easily removed before mucosal alterations, atelectasis, emphysema, or suppurative complications set in and if the patient is asymptomatic, no further inpatient care should be necessary. Observing patients for 1-2 days postextraction may be appropriate, in case complications from impaction or extraction arise. Noncardiogenic reexpansion pulmonary edema, airway inflammation, hemoptysis, pneumothorax, tracheoesophageal fistula, pneumonia, atelectasis, fever, or ventilatory failure may require continued hospitalization, including ICU monitoring, intubation, mechanical ventilation, repeated bronchoscopic procedures (eg, directed suctioning of inspissated pus, laser therapy of bleeding, obstructing granulation tissue or polyps), antibiotics, corticosteroids, bronchodilators, or chest physical therapy.

Deterrence/Prevention

Pay attention to the size and texture of foods and objects available to children and adults with impaired mentation or ability to protect the airway (eg, impaired chewing, swallowing, coughing). Removal of appliances prior to manipulation of the teeth or airway is essential. Note the condition of medical equipment at the beginning and end of procedures involving the pharynx, larynx, respiratory tract, or digestive tract. Sedatives and topical anesthetics increase the risk for aspiration; therefore, use them sparingly. Oral pierced jewelry should be removed prior to general anesthesia, emergency airway management, or other such manipulation of the oral pharynx because of the risk of dislodgement and aspiration.[11]

Complications

The severity of the complications of foreign body aspiration depends on the size, shape, composition, location, and orientation of the aspirated object. The following complications may ensue:

Delay in treatment can result in the following conditions:

Chronic complications may be due to the foreign body itself or to trauma induced during attempts to remove the object. The complication rate increases if extraction is delayed. Noncardiogenic pulmonary edema may develop with reexpansion of an atelectatic lung. Bleeding from granulation tissue is usually mild but can be massive. Relief of long-standing bronchial obstruction can result in soiling of the bronchial tree with purulent secretions. The following unusual complications may ensue:

Prognosis

Almost all foreign bodies can be removed from the tracheobronchial tree using bronchoscopy. The complication rate increases as the time to the diagnosis and extraction of the object exceeds 24 hours. Data are lacking regarding the long-term consequences of long-present foreign bodies that cannot be extracted bronchoscopically and are incidentally found on chest radiographs in completely asymptomatic patients. Periodically monitor these patients for signs of airway obstruction, perforation, suppurative complications, or the development of scar carcinoma.

Author

Martin E Warshawsky, MD, FACP, FCCP, Director of Respiratory Intensive Care Unit, Elmhurst Hospital Center; Clinical Assistant Professor, Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Mount Sinai School of Medicine

Disclosure: Nothing to disclose.

Specialty Editors

Stephen P Peters, MD, PhD, FACP, FAAAAI, FCCP, FCPP, Professor of Internal Medicine, Pediatrics, and Translational Science, Associate Director, Center for Genomics and Personalized Medicine Research, Director of Research, Section on Pulmonary, Critical Care, Allergy and Immunologic Diseases, Wake Forest University School of Medicine

Disclosure: See below for list of all activities None None

Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

Timothy D Rice, MD, Associate Professor, Departments of Internal Medicine and Pediatrics and Adolescent Medicine, St Louis University School of Medicine

Disclosure: Nothing to disclose.

Chief Editor

Zab Mosenifar, MD, Director, Division of Pulmonary and Critical Care Medicine, Director, Women's Guild Pulmonary Disease Institute, Professor and Executive Vice Chair, Department of Medicine, Cedars Sinai Medical Center, University of California, Los Angeles, David Geffen School of Medicine

Disclosure: Nothing to disclose.

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