Pulmonary Aspiration: Foreign Bodies and Massive Aspiration
John L. Colombo, MD, FAAP, and Paul H. Sammut, MB, BCh, FAAP, FCCP
•Aspiration of materials that are foreign to the lower respiratory tract is a relatively common event seen in the typical pediatric practice, in terms of both prevalence and severity of illness.
•Aspiration may occur in healthy children and adults and may be clinically undetectable, but it may also be a normal event, occurring particularly during sleep.
•Acute aspiration may be life-threatening, particularly when it involves massive aspiration of gastric contents, hydrocarbons, or foreign bodies.
•Dysphagia with aspiration is reportedly the most common cause of recurrent pneumonia that results in hospitalization.
•The 3 major types of aspiration lung disease are (1) airway foreign body, (2) massive aspiration, and (3) recurrent small-volume aspiration (discussed in Chapter 74, Gastroesophageal Reflux and Recurrent Small-Volume Aspiration).
•While infectious consequences may develop secondary to any of these events, infectious pneumonia is discussed in Part IV, Section 2 of this book: Parenchymal Infections.
Airway Foreign Body: Mechanical Obstruction
•Aspiration of foreign bodies is most common at 1–3 years of age, but it occurs in all age groups. The incidence is up to twofold higher in boys.
•Food is the most commonly aspirated material in toddlers, whereas small, nonedible objects are more commonly aspirated in older children (see Box 73-1).
•Most children have a sudden onset of symptoms. However, in ≥25% of cases, the parents are not aware of any aspiration or choking event.
•There is often an asymptomatic period after the choking spell, once the foreign body becomes lodged in the lower tracheobronchial tree.
•The most common presentation is a history that includes a choking event, followed by acute cough, but parents will often not associate an acute short coughing event with a foreign body.
•A careful history should be obtained to elicit the details surrounding the beginning of a cough. Transient or persistent cough is the primary symptom in approximately 75% of children with foreign bodies in the airway (Box 73-2).
•Physical findings may demonstrate asymmetrical chest expansion, decreased breath sounds over the affected lung, and/or localized wheezing, or findings may be normal. However, a tracheal foreign body is more likely associated with bilateral wheezing, which is usually monophonic in nature.
•Sudden onset of respiratory symptoms (stridor, wheeze, cough)
•Patient is in the highest-risk age group of 1–3 years
•Patient has a history of choking events
•Radiographic findings include air trapping and/or atelectasis, especially on decubitus or inspiratory-expiratory views
a Refer the patient if there is a high or low level of suspicion for foreign-body aspiration in the presence of persistent symptoms or findings.
•Chest radiographic findings, carefully reviewed, are often highly suggestive of either radiopaque or radiolucent opaque foreign bodies (see Figure 73-1).
•Most foreign bodies are radiolucent; thus, indirect evidence is usually needed for a diagnosis. Bilateral decubitus radiographs are most useful in children because they require no patient cooperation (Figure 73-2). Inspiratory-expiratory radiographs can yield a diagnosis in older, may not cause asymmetrical findings.
cooperative children (Figure 73-3). Foreign bodies cause air trapping on
the affected side from a ball-valve effect. Regardless of whether decubitus
or inspiratory-expiratory radiographs are obtained, the abnormal lung is
identified by the fact that it does not deflate and remains unchanged on
all images. Tracheal or bilateral foreign bodies, which are fortunately rare,
•A chest radiograph with normal findings does not exclude a foreign body in the airway. Fluoroscopy, preferably pulsed low-dose fluoroscopy, is an option for quickly and inexpensively further evaluating children with unclear radiographic findings and uncooperative children.
•Atelectasis may be a later finding and may occur with complete airway obstruction.
•Low-dose multidectector computed tomography and virtual bronchoscopy are most useful for detecting residual foreign bodies after bronchoscopies if the patient remains symptomatic or has continued abnormalities on plain radiographs (Figure 73-4).
Figure 73-1. Foreign body in a young child. Frontal chest radiograph in a 9-year-old boy shows a large nail lodged in the trachea and the right mainstem bronchus, which is causing right middle lobe atelectasis and obscuring the right-sided heart margin and right hemidiaphragm. Air bronchograms are also noted.
a change in patient position, which indicates air trapping. Conversely, the left lung changes in volume with the change in patient position, which is a normal finding that indicates no air trapping. The peanut was removed via a bronchoscope.
Figure 73-3. Chest radiographs of an 11-year-old boy with a left mainstem foreign body (a tire chip). Frontal A. inspiratory and B. expiratory images are shown. The normal right lung deflates during expiration, whereas the abnormal left lung remains unchanged in volume. The incidental finding of right aortic arch is noted. From Colombo J, Sammut PH. Aspiration (foreign body, food, chemical). In: Light MJ, Blaisdell CJ, Homnick DN, Schechter MS, Weinberger MM, eds. Pediatric Pulmonology. Elk Grove Village, IL: American Academy of Pediatrics; 2011:619–636.
•If complete airway obstruction occurs with a witnessed choking event, abdominal thrusts (Heimlich maneuver) are indicated for children >1 year of age. For infants <1 year of age, place the infant in the head-down position and perform chest thrusts and back blows.
•If a foreign body is likely, on the basis of the history, physical examination findings, or radiographic findings, referral for bronchoscopy should be made as soon as possible. Rigid bronchoscopy should be performed as
soon as safely possible (a) to prevent possible dislodgement of the foreign body into a more central and potentially life-threatening position in the airway, (b) to reduce local inflammation, which might make the foreign body more difficult to remove, and (c) to reduce parenchymal lung complications, including pneumothorax, atelectasis, and bronchiectasis.
•Small distal foreign bodies may require special instrumentation and, sometimes, fiber-optic bronchoscopy. If the diagnosis of foreign body is less certain, flexible bronchoscopy can be used to confirm this diagnosis, provide another diagnosis, and, sometimes, prevent the need for more invasive, rigid bronchoscopy.
•Rarely, a thoracotomy with bronchotomy may be necessary to remove a deeply embedded foreign body.
•Providing preemptive education to parents of infants and toddlers should be standard in pediatric practice. This includes advising parents that commonly aspirated foods, such as peanuts or similarly sized foods and other objects, should be kept out of reach, that food should be cut into small pieces, and that latex balloons should not be allowed in the home.
• A history of acute choking should never be ignored.
• Any child with a sudden onset of choking, followed by coughing or wheezing, should be referred for evaluation via rigid bronchoscopy.
• Refer the patient if the diagnosis is in question.
• A child with a choking event but no further symptoms, such as cough, dyspnea, fever, and normal physical examination and chest radiographic findings, may not require bronchoscopy. However, if the choking event is followed by any of these findings, referral should be immediate.
• Refer any child for flexible bronchoscopy in the presence of (a) chronic problems, such as persistent chest radiographic abnormalities, wheezing, or cough that is unresponsive to asthma therapy, or (b) recurrent pneumonias in the same location, even if there is no history for choking. Although flexible bronchoscopy is generally not used for removal of a foreign body, it has advantages for the initial procedure in that infected secretions are easier to culture (common in retained foreign bodies), and it can be used to help plan the best strategy for subsequent removal with a pediatric surgeon and/or otolaryngologist.
• Follow-up is important to monitor the patient for late-onset signs or symptoms and to obtain repeat radiographs if these symptoms develop.
When to Admit
• Admit any child that has (a) chronic problems, such as persistent chest radiographic abnormalities, wheezing, or cough that is unresponsive to asthma therapy, or (b) recurrent pneumonia, if bronchoscopy cannot be performed promptly. The child should be hospitalized for close observation with nil per os (nothing by mouth) status until bronchoscopy can be performed.
• Extracorporeal membrane oxygenation has been lifesaving in unusually complicated cases when a tracheal foreign body could not be removed without the potential loss of airway support.
• Large-volume aspiration is typically associated with vomiting, particularly with an altered level of consciousness, during which upper-airway protective reflexes are diminished.
• This may occur in children with trauma, seizures, or clinically significant underlying neuromotor disorders, as well as during general anesthesia.
• Animal studies have shown that volumes >1 mL/kg or pH levels <2.5 are associated with the most severe outcomes, although aspiration of particulate material also contributes to clinically significant lung injury.
• When acute massive aspiration is suspected, immediate management is paramount.
•There is no difficulty in establishing the diagnosis of acute aspiration when the patient is observed to vomit and choke immediately afterward. Whether witnessed or not, the patient typically presents with dyspnea and, possibly, cyanosis.
•Evidence of vomitus may still be present in the oropharynx. If the child has a tracheostomy tube, suctioning of the tube should be performed and may return some formula or stomach contents.
•Clinical observation frequently reveals accessory muscle use and retractions. Coarse inspiratory crackles may be auscultated throughout the chest. Wheezes of varying pitch may also be found. In severe cases, the patient may have lost consciousness or experienced respiratory arrest. Generalized seizures may occur secondary to associated hypoxic encephalopathy.
•If it is suspected that inhaled substances had large particulate
matter, bronchoscopy may be warranted once a secure or safe airway is established.
—Identification and removal of large airway particles are of diagnostic value, as well as potential therapeutic value.
—If no large particles are seen in the airways, bronchoalveolar lavage may still demonstrate diagnostic foreign material, such as meat or vegetable fibers.
—If lipid is aspirated, lipid-laden macrophages may be observed within a few hours after aspiration.
•The classic findings are “asthma-like,” as described by Mendelson, whose original description was of complications of aspiration during obstetric anesthesia.
—These findings may include coughing, wheezing, tachypnea, and possibly cyanosis.
—After a latent period of 1–3 hours, fever and crackles may develop.
—Initial radiographic findings typically show bilateral multilobar infiltrates, which then worsen over the next 24–36 hours secondary to the inflammatory response (Figure 73-5).
—Perioperative aspiration is uncommon with anesthesia today.
•Bronchoscopy may play a role in some cases of massive aspiration.
•There is no value in attempting to neutralize acid aspiration, because this occurs endogenously within seconds after the event.
•Corticosteroids have not been shown to be beneficial. However, if administered immediately—essentially simultaneously with an aspiration event—there may be some benefit.
Figure 73-5. Aspiration due to foreign body in a 3-year-old girl who vomited and aspirated a large volume of gastric material. Frontal chest radiograph shows right lower lobe focal opacity. An endotracheal tube, nasogastric tube, and central line overlie the midtrachea, stomach, and superior vena cava, respectively.
•Antibiotics are not indicated in the immediate treatment of most cases of large-volume aspiration.
•General supportive measures, including supplemental oxygen, bronchodilators, and mechanical ventilation, are the mainstays of acute treatment.
•Antibiotics are generally reserved for suspected infectious complications of a chemical pneumonitis. If antibiotics are deemed necessary for a severely compromised patient or for other reasons, they should be individualized, depending on the clinical situation.
—For example, if the patient has been institutionalized, more broad-spectrum antibiotics would be warranted, including coverage for gram-negative bacteria, as well as methicillin-resistant Staphylococcus aureus and anaerobes.
•For patients at risk for vomiting and aspiration:
—Gastric volume should be minimized.
—Gastric acid suppression should be considered.
—Elevating the head of the bed to 30–45 degrees, avoiding excess sedation (if possible), and monitoring gastric residual volumes during enteral feedings may all be helpful preventive measures.
—If vomiting is witnessed in a patient with a poorly protected airway or an artificial airway, immediate suctioning of the airway is critical.
•A child with recurrent pneumonia or persistent chest radiographic abnormality, dysphagia, coughing or choking with feedings, or recurrent wheezing that is not responsive to routine asthma therapy should be referred for further evaluation.
•Refer the patient if aspiration is suspected in the presence of severe under- lying disease, such as congenital heart disease or pulmonary hypertension.
When to Admit
•All patients who become rapidly dyspneic from large-volume aspiration should be admitted.
•Unless the physical examination findings, oxygen saturation level, and chest radiographic findings are normal, all patients suspected to have large-volume aspiration should be admitted for close observation.
•If a patient is able to maintain near-normal blood oxygen levels with reasonable amounts of supplemental oxygen (fraction of inspired oxygen [FIO2] <0.6), is only mildly or moderately dyspneic, is not in an altered neurological state, and can be monitored by experienced staff, it is reasonable that he or she can be cared for in a community hospital.
•The patient should be observed closely for a minimum of 48 hours because late-onset deterioration can occur.
•A child whose condition deteriorates rapidly, requires increasing oxygen supplementation, becomes obtunded, or requires intubation and assisted ventilation should be transferred to a center with pediatric pulmonary and critical care specialists. It is likely that, in these situations, the patient will require prolonged and intensive treatment and will require extended follow-up in specialty clinics.
Resources for Families
•Choking Prevention (American Academy of Pediatrics). www.healthychildren.org/English/health-issues/injuries-emergencies/Pages/Choking-Prevention.aspx
•Responding to a Choking Emergency (American Academy of Pediatrics). www.healthychildren.org/English/health-issues/injuries-emergencies/Pages/Responding-to-a-Choking-Emergency.aspx
•A high index of suspicion is necessary for airway foreign body because the history, physical examination findings, and radiographic findings may be normal. The ultimate diagnosis can often only be established by means of bronchoscopy. Choking episodes should never be ignored.