History of Present Illness

Obtaining a good history plays a vital role in effectively diagnosing an aerodigestive foreign body. Three clinical phases of aspiration and ingestion of foreign bodies are recognized: The first stage is the impaction of the foreign body, which elicits episodes of choking, coughing, or gagging. In the second stage, these symptoms wane as the foreign body settles into a stationary location and the tracheoesophageal reflexes tire out; this asymptomatic stage can last hours to weeks, which may delay diagnosis. In the third phase, complications can arise such as obstruction, infection, or perforation.

A history of witnessed ingestion, aspiration, or a choking event warrants further evaluation and workup. Information that is important to elicit from the parents includes the approximate time of ingestion or inhalation, a history of esophageal dysfunction, and the severity and duration of swallowing or respiratory dysfunction. Symptoms of foreign body inhalation most commonly include cough, dyspnea, wheezing, cyanosis, or stridor. When an unusual foreign body is suspected to have been aspirated or ingested, it may also be helpful to have the parents bring in a similar object from home. In children with chronic symptoms suspicious of asthma who do not respond to steroids or bronchodilators, foreign body inhalation should remain in the differential diagnosis.

Typical signs and symptoms of esophageal foreign body ingestion include drooling, dysphagia, emesis, food refusal, and chest pain. One study found that the most common presenting symptom was vomiting, which occurred in 28% of their study population. In this study, 47% of patients were asymptomatic, but an overwhelming 92% had a witnessed episode of ingestion, which demonstrates again the importance of the history. In more severe cases, esophageal foreign bodies in young children may also cause respiratory symptoms as a result of swelling in the common wall shared by the trachea and esophagus.

Physical Examination

The most reliable clinical findings for airway foreign bodies include cough, decreased lung sounds, and wheezes. Other signs can include fever, recurrent pneumonias, tachypnea, hypoxemia, or crackles. Chest auscultation is very important because asymmetry of breath sounds or a prolonged expiratory phase of respiration can signal a bronchial foreign body.

Esophageal foreign bodies manifest with fewer physical examination findings, but infants can have nonspecific findings such as drooling, choking, or poor feeding. Young children who have smaller, more easily compressible tracheas can exhibit respiratory symptoms from external tracheal compression. Older children may present with odynophagia and dysphagia. One study found that 89% of children with foreign body ingestion had no abnormalities on physical examination. Clinical suspicion should remain high with the appropriate history even in the face of a normal examination.

Diagnostic Imaging

Although a normal imaging study does not rule out the presence of a foreign body, imaging is a helpful tool in diagnosing aerodigestive foreign bodies. Standard frontal and lateral radiographs are the imaging tests of choice for suspected airway foreign bodies. Radiopaque airway foreign bodies should be straightforward to diagnose, whereas organic and other radiolucent airway foreign bodies may be more difficult. In those cases, other radiographic signs such as unilateral emphysema, hyperinflation, localized atelectasis or infiltrates, and mediastinal or esophageal air trapping may also be indicative of an airway foreign body. According to a recent review, only 11% of airway foreign bodies were radiopaque, which emphasizes the need to search for these other subtle radiologic clues. Often, the only evidence of an airway foreign body will be localized air trapping or atelectasis. Even if imaging studies are normal, a convincing history or witnessed ingestion or aspiration is sufficient to warrant empiric rigid endoscopy.

Both posteroanterior (PA) and lateral views should be obtained to help differentiate tracheal from esophageal foreign bodies, as seen in Figure 28-1 . The classical teaching that sagittally oriented foreign bodies lie in the trachea and coronally positioned foreign bodies are in the esophagus does not universally hold true. Esophageal foreign bodies may be found in either the sagittal or coronal configuration; in contrast, tracheal foreign bodies more commonly lodge in the sagittal plane because of the longitudinal orientation of the vocal cords and lack of cartilage in the posterior tracheal wall. If the object appears to overlap the tracheal boundaries on a PA view, it is highly unlikely to be in the trachea. A lateral radiograph may also reveal soft tissue swelling or loss of normal cervical lordosis, or it may demonstrate that the object lies posterior to the trachea in the esophagus. Button batteries have a characteristic double contour on a lateral view but may be mistaken for a coin if only a PA view is obtained.

A posteroanterior radiograph demonstrates a coin lodged in the aerodigestive tract and oriented in the coronal plane, indicating it is likely in the esophagus. B, A lateral radiograph confirms the location of the coin to be posterior to the trachea in the esophagus.

(Courtesy Andrew Murr, MD.)

If suspicion for an airway foreign body is high but existing films are equivocal, special films can be obtained. Expiratory views are obtained by waiting for the patient to be in the expiratory phase of breathing or pressing on the patient’s abdomen to encourage a full expiration. Bilateral decubitus views are obtained by imaging a frontal view with the patient lying on each side. However, a recent study indicated that decubitus films may not be useful because false positives are increased, whereas the number of true positives remains the same. Several studies have shown that as high a proportion as 25% of children with a bronchoscopy-proven foreign body have normal radiographs, which underscores the importance of a thorough history and physical examination.

Fluoroscopy of the airway may also be done to assess symmetric diaphragmatic movement of both lungs and to provide the clinician with a dynamic view of the airway. It is particularly useful when the child is unable to cooperate for the imaging examination. However, this examination is highly dependent on the expertise of the radiologist performing it and can vary at different institutions.

Computed tomography (CT) and virtual bronchoscopy are two diagnostic tools that are under investigation, but their major drawback in the pediatric population is the risk of radiation exposure. A standard chest radiograph exposes a child to 0.1 millisieverts (mSV) of radiation, which is equivalent to several days of background environmental radiation. In contrast, a high-resolution chest CT exposes a child to 7 mSV or 70 chest radiographs. The lower-resolution CTs for diagnosing airway foreign bodies are generally in the range of 1.5 mSV, equivalent to 15 standard chest radiographs. In addition to radiation exposure is the added drawback of increased cost and required equipment and personnel familiar with this specialized protocol. Kosucu and colleagues investigated low-dose multiple-detector CT virtual bronchoscopy, and in 23 patients with suspected airway foreign body, the method had a 100% sensitivity and specificity when compared with bronchoscopy. Although radiation risk remains an issue, the lower doses used in these examinations may make this a viable diagnostic tool in the future.

As a diagnostic tool, flexible bronchoscopy is also used to locate airway foreign bodies. Righini and colleagues demonstrated utility in this method for children who had a suspected foreign body but no overwhelming physical examination evidence to suggest it. By ruling out a foreign body on flexible bronchoscopy, some of these children were able to avoid rigid bronchoscopy and its inherent risks. Patients found to have a foreign body on flexible bronchoscopy then underwent rigid bronchoscopy for extraction.

For esophageal foreign bodies, the standard PA and lateral radiographs are recommended. The two views can both provide localizing information and can identify the presence of multiple foreign bodies. In a large review of 325 patients who presented with suspected foreign body ingestion, 60% had a radiopaque foreign body seen on radiography. In another study, 71% of radiographs taken were able to localize the foreign body in the esophagus. Even if a radiopaque foreign body is not identified, subtle signs on a lateral neck radiograph can be seen, such as a widened prevertebral shadow and loss of lordosis. In one series, 38% of patients with suspected foreign body ingestion demonstrated these findings on a lateral neck radiograph.

Anesthetic Considerations

For esophageal foreign bodies, the child should be intubated to minimize the possibility of aspirating the foreign body upon removal and to reduce tracheal compression by the esophagoscope. The pediatric anesthesiologist should take particular care for high esophageal foreign bodies, which have an increased risk of dislodging into the airway. In rare cases, a high esophageal foreign body may be visualized at the esophageal inlet during direct laryngoscopy and can be carefully removed with Magill forceps.

The choice of anesthesia for bronchoscopic removal of foreign bodies has been broadly debated. The three main considerations are 1) method of induction, 2) type of ventilation during bronchoscopy, and 3) maintenance of anesthesia. The debate centers around the risk of converting a partial obstruction into a more complete obstruction when using any form of positive-pressure ventilation. Traditionally, spontaneous ventilation with negative-pressure inhalation has been the preferred method because it takes advantage of the natural increase in tracheal and bronchial cross-sectional area during inspiration, and the risk of distal migration of the foreign body with positive-pressure ventilation is avoided. Spontaneous ventilation also lowers the risk of inability to ventilate, should the foreign body strip off the extraction forceps during the procedure. However, it may be difficult to achieve an adequate depth of anesthesia that avoids patient movement, which can cause bronchial tree injury, while also preventing apnea and resultant hypoxemia. Alternatively, controlled jet ventilation ensures a steady level of deep anesthesia and ventilation, which ensures better oxygenation, less coughing or bucking, and less patient movement but has the risk of displacing the foreign body further down the airway. One study found that in the spontaneously ventilated group, those anesthetized with sevoflurane had a higher rate of successful foreign body removal than those given intravenous anesthetics. The spontaneous ventilation group had a higher rate of intraoperative hypoxemia compared with the manual jet ventilation group. Additionally, younger age, longer duration of surgery, and preoperative pneumonia were all added risk factors for increased intraoperative hypoxemia.

Bronchoscopy

Preparation is critical for ensuring a successful rigid bronchoscopy. Prior to induction of general anesthesia, the correct laryngoscopes and bronchoscopes for the patient age and all associated equipment should be prepared ( Fig. 28-3 ). The anesthetic plan and back-up plans should be discussed with the pediatric anesthesiologist before the patient is transported to the operating room. After mask induction with an inhalational agent, topical lidocaine is used to anesthetize the vocal cords. Care must be taken in young children to calculate the appropriate maximal dose of lidocaine by weight. Direct laryngoscopy is then performed, and a thorough search of the oropharynx, hypopharynx, and larynx should be performed to ensure that no foreign bodies are present. Next, the rigid bronchoscope is inserted into the trachea. Once the bronchoscope has been introduced, the anesthesiologist may connect to the ventilation port of the bronchoscope. The trachea and bronchi are examined, and the foreign body is visualized. Using the appropriate telescopic forceps, the foreign body, forceps, and bronchoscope are removed as a single unit. Care should be taken to avoid premature release of the foreign body because this can result in airway obstruction. A repeat bronchoscopy should be performed to confirm the absence of other foreign bodies. A flexible suction catheter can be placed down the side port for suctioning of secretions or debris under direct vision; rigid suction can also be introduced through the bronchoscope. For sharp objects, the sharp end should ideally be grasped and kept within the tip of the bronchoscope as the object is being removed to minimize tracheal or laryngeal mucosal trauma. If an object cannot be retrieved and obstruction is nearly complete or complete, the bronchoscope and the object can be pushed farther down the bronchus to temporarily relieve the obstruction. Rarely, a tracheotomy or thoracotomy may be required to ventilate and subsequently remove the foreign body.

Bronchoscopy equipment. Appropriate laryngoscopes should be available. Laryngotracheal anesthetic with the correct weight-based dose has been prepared in advance, and age-appropriate bronchoscopes have been laid out and tested prior to starting the procedure. Suspension equipment and laryngeal suctions are all available.

(Courtesy Matthew Russell, MD, and Jeffrey Markey, MD.)

Flexible bronchoscopy has also been used for airway foreign body removal. Tang and colleagues reported successful removal of airway foreign bodies in 91.3% of children using this maneuver. However, concern with flexible bronchoscopy remains because the airway is not protected, and there may be no way to ventilate the patient if control of the foreign body is lost. Flexible bronchoscopy is helpful for removing objects in the distal airways, in which rigid bronchoscopes are too large to pass.

Certain interventions are contraindicated in management of foreign bodies. Blind finger sweeping of the hypopharynx may lodge a foreign body in the larynx or esophagus and can cause tracheal compression. Chest physical therapy and bronchodilators may create complete blockage. Meat-dissolving substances may cause esophageal necrosis and precipitate mediastinitis.

Esophagoscopy

Whereas only a minority of esophageal foreign bodies require endoscopic removal, numerous maneuvers can be tried to retrieve them. In one study of 84 children with attempted endoscopic removal, 12% were successfully retrieved with a laryngoscope and Magill forceps; 51% were recovered using rigid esophagoscopy and forceps; 5% were retrieved with flexible endoscopy and forceps; and 32% did not have a visualized foreign body. If a child is asymptomatic, the decision to intervene is based on a combination of physical examination findings, imaging studies, and a description of the object ingested. If the child is symptomatic, an attempt at endoscopic removal should be made. Objects in the oropharynx can be removed with a laryngoscope and Magill forceps, whereas esophageal foreign bodies can be removed directly or, alternatively, can be pushed into the stomach and retrieved from there. Sedation and anesthesia can cause relaxation of the esophageal sphincters, which can cause the object to spontaneously migrate into the stomach. Foreign objects located in the stomach in an asymptomatic child can be observed unless the object is a battery, if it is sharp and large, or if it has been present for a prolonged time. The mean intestinal transit time is variable but averages 3.8 days.

Postoperative Management

Postoperatively, if the procedure was uncomplicated, the child can be discharged from the recovery room with scheduled follow-up to ensure symptoms have resolved completely. If concern for a foreign body remnant remains, endoscopy can be repeated in a few days. Depending on the difficulty of extraction, a postoperative radiograph should be ordered. After esophagoscopy, the child should be monitored for signs or symptoms of mediastinitis that include fever, tachycardia, and tachypnea. Antibiotics or steroids are not routinely indicated postoperatively unless significant airway or esophageal injury was identified. Steroids are routinely used to reduce postoperative laryngeal and tracheal edema but have not been shown to reduce complication rates.

Complications

Complication rates of aerodigestive endoscopy are reported from 1% to 8%. The most common complications of rigid bronchoscopy include failure to remove the foreign body, laryngeal edema, pneumothorax, pneumomediastinum, and subcutaneous emphysema. Laryngeal edema may rarely be significant enough to warrant intubation or tracheotomy. One group found that the most important variables to predict complications included a history of previous bronchoscopy, increased duration of the bronchoscopy, and type of foreign body. Organic matter is associated with higher complication rates because of increased airway edema, bronchial secretions, and the tendency to develop a chemical bronchitis as a result of the proteins and oils contained in organic matter. Mortality rates in the literature vary from 0.2% to 1.0%.

For esophagoscopy, complications include mucosal injury, bleeding, and rarely perforation, which can cause mediastinitis. In a minority of cases, esophageal endoscopic removal is unsuccessful and requires surgical intervention such as a thoracotomy, esophagotomy, gastrotomy, or jejunotomy.