A 40 kg, 12-year-old boy with a history of cervical spine fusion due to syringomyelia presents to the hospital following the accidental inhalation of a pushpin during sneezing. There is no associated thoracic scoliosis or any neuromuscular deficits.

What Are the Initial Clinical Steps in Patient Management?

Initial management when presented with a definitive history of aspiration of a foreign body begins with the ABCs. An awake, alert patient without overt airway distress will permit a more complete workup, while a severely distressed patient with stridor and desaturation will mandate acute stabilization prior to rapid transfer to the operating room for surgical removal. All patients should have continuous pulse oximetry. Supplemental oxygen may be provided to maximize oxygenation. To optimize patient care and potentially minimize the need for emergency intervention, a member of the anesthesia or surgical team should accompany the patient during airway stabilization and transportation to the operating room.

Respiratory distress or the presence of stridor implies compromise of the airway and reduced airflow. Heliox (70% helium and 30% oxygen) will improve oxygenation by maximizing laminar airflow and reducing airflow resistance. The use of Heliox serves as a temporizing measure in the setting of foreign body aspiration in young children as it decreases the work of breathing and the associated anxiety.¹ Intravenous dexamethasone at a dose of 0.5 mg·kg⁻¹ may be beneficial in reducing the mucosal edema which partly contributes to the airway obstruction.² Aerosolized epinephrine may be an additional means of reducing airway edema. The use of bronchodilators is considered to be relatively contraindicated until the foreign body is removed from the airway, as its use may predispose to dislodgement and distal migration of the foreign body due to an increase in airway caliber. Bronchodilators, however, are important adjuncts to pulmonary toilet following foreign body removal.³

What Are the Appropriate Investigations for a Foreign Body in the Trachea?

Radiologic studies are used as an adjunct to the physical examination in diagnosing suspected aerodigestive foreign bodies. Anteroposterior and lateral chest radiographs with inspiratory and expiratory views are helpful tools if the foreign body is opaque, or if bronchial obstruction is present. Lateral decubitus films are helpful when the patient is unable to cooperate for inspiratory/expiratory views. Typical radiologic findings often reveal a foreign body shadow, air trapping, segmental or lobar collapse, or consolidation. Unfortunately, the false negative rate (i.e., normal chest x-ray) ranges between 24% and 33% when compared to bronchoscopic findings.⁴

Spiral CT has shown some benefit when faced with persistent symptoms in a pediatric patient in the setting of an atypical history and normal chest x-ray. Fluoroscopy and cine CT are of little added benefit when a timely workup is of essence, especially if a plain radiograph or spiral CT has already confirmed the presence of a foreign body.⁴ The gold standard for diagnosing an aspirated foreign body is rigid bronchoscopy under general anesthesia.^3,5

Do Different Types of Foreign Bodies (Organics, Metals, Plastics) Influence Patient Management and Outcomes?

Organic matter (nuts, corn, seeds, etc.) and plastics are radiolucent items that are not commonly visualized on x-ray. Organics must be removed as soon as possible as the diameter of the object will increase over time due to the absorption of secretions and moisture. This may convert a stable, partial obstruction to an acute, complete obstruction, or obliterate the available space around the foreign body complicating removal by forceps. Furthermore, over time the organic matter will become more friable, potentially breaking into multiple pieces, making complete removal very difficult. This enhances the risk of airway obstruction and infection in the distal, smaller generation bronchi.

Additionally, organic matter with natural oils (nuts, bacon, etc.) will create a local inflammatory mucosal response enveloping the foreign body in granulation tissue. This local tissue reaction begins rapidly after only a few hours of mucosal contact and progresses over time. The development of granulation tissue impedes direct visualization of the foreign body, more readily obstructs distal airflow, and creates bleeding with even minor manipulation thus further hampering visualization and foreign body removal. Once bleeding from granulation tissue has begun, repeated instillations of dilute epinephrine through the rigid bronchoscope can help briefly diminish the bleeding to assist with further attempts at foreign body retrieval. The bleeding will ultimately stop once the foreign body is removed with its enveloping granulation tissue.

What Are the Pathophysiologic Changes in the Presence of an Aspirated Foreign Body?

Determining the site of airway obstruction, the size and shape of the aspirated object, and the timeline since obstruction are crucial to patient outcomes and guide the plan for removal. Airway obstruction following foreign body aspiration may be total or partial, depending on all of the above factors.

Toddlers, under 3 years, are at highest risk of foreign body aspiration as they explore their environment by placing encountered objects in their mouths, are more likely to talk, laugh, and run while eating, have relatively immature laryngeal protective reflexes,⁵ and incomplete dentition. The most commonly aspirated organics are nuts (peanut, sunflower seed), meat (chicken, hot dog), popcorn, and carrots. Fatalities are most frequent with hot dogs and other meats, candies, grapes, and peanuts.⁶

A foreign body lodged in the lower airway may manifest with different pulmonary findings depending on the type of impaction. Four lower airway obstructive mechanisms have been described: check valve, ball valve, bypass valve, and stop valve.⁷ Check valve implies air can be inhaled but not exhaled, creating alveolar air trapping and flattening of the ipsilateral diaphragm. This is in contrast to a ball valve which allows expiration but not inspiration of air, creating segmental bronchopulmonary collapse. A bypass valve obstruction allows partial airflow on both inspiration and expiration around the foreign body and may not exhibit specific clinical findings. A stop valve creates complete obstruction to airflow causing airway collapse and consolidation distal to the obstruction.⁷

The ability to correctly ascertain the type of obstruction and object aspirated may help determine the stability of the patient’s airway and the requisite acuity of intervention. This key point is of utmost importance when the patient is not distressed, possibly lulling the practitioner into a false sense of (airway) security.

What Are the Usual Clinical Presentations of a Foreign Body in the Airway With or Without Airway Obstruction and Air Trapping? What Are the Specific Airway Concerns in This Patient?

Presenting symptoms following foreign body aspiration are related to the type of object aspirated, location of the object, and the overall duration of the obstructive event. Airway obstruction may be complete or partial. Complete obstruction of the trachea or large airway is an emergency situation usually associated with hypoxemia, cardiovascular compromise, and subsequent collapse. In contrast, partial obstruction can often present with more subtle symptoms such as coughing, focal or diffuse wheezing, and decreased air entry on the affected side.^3,8 These symptoms may progress over time to drooling, dyspnea, stridor, and respiratory distress.

It is critical to appreciate that to produce symptoms a foreign body must encroach on 75% of the airway lumen to create turbulent airflow. This degree of obstruction may occur acutely, due primarily to the foreign body itself or secondarily, due to the local tissue reaction. Aspiration of organic matter will promote, over time, local airway swelling and the production of granulation tissue. Thus even a small foreign body can produce significant obstructive symptoms when left in the airway for as little as 5 to 7 days. This generally necessitates immediate intervention to avoid a disastrous outcome.⁸

In this patient, the aspirated sharp foreign body may be found anywhere in the upper airway, down to the level of the carina and occasionally in the mainstem bronchi. Sharp objects, like pins, will generally be found with the sharp end embedded in the mucosa proximally, while the larger, blunt end is distal. It is unlikely that a pushpin, in and of itself, would cause obstruction of the larger airways. However, the associated mucosal edema, and/or displacement into the smaller generation bronchi, may create airway obstruction.

Our patient is able to provide an accurate history of aspiration and subsequent, persistent cough. His airway is currently stable. However, his previous cervical fusion may provide a challenge for both the anesthesia practitioner and endoscopist. The following sections will further delve into anesthetic management and the surgical options presented by this challenging scenario. A key principle in managing the airways of children is to ensure communication between the anesthesia practitioner and the surgeon prior to the patient’s arrival in the operating room. It is essential that the surgical setup be ready prior to the induction of anesthesia, that a backup plan has been discussed and agreed upon, and that the equipment for performing a surgical airway is available.

What Are the Anesthetic Options if the Patient Is Uncooperative? How Would You Approach the Induction of This Patient?

Children with airway obstruction pose a challenge to the anesthesia practitioner. Physiologically, children have a limited functional residual capacity (FRC), reduced respiratory reserve, increased shunting, and a propensity for airway closure (laryngospasm and bronchospasm). In the setting of a relative increase in oxygen consumption and suboptimal ventilation, the anesthesia practitioner is faced with a patient who will likely develop hypoxemia rapidly. An inhalation induction is likely to be prolonged in the presence of reduced alveolar ventilation due to airway obstruction.