Foreign body aspiration
|Foreign body aspiration|
|Chest x-ray of a child after aspiration of a peanut: hyper-inflated left lung due to a valve mechanism of the peanut in the bronchus|
Signs and symptoms
Signs and symptoms of foreign body aspiration vary based on the site of obstruction, the size of the foreign body, and the severity of obstruction. 20% of foreign bodies become lodged in the upper airway, while 80% become lodged in the mainstem or lobar bronchus. Signs of foreign body aspiration are usually abrupt in onset with coughing, choking, and/or wheezing; however, symptoms can be slower in onset if the foreign body does not cause a large degree of obstruction of the airway.
Classically, patients present with acute onset of choking. In these cases, the obstruction is classified as a partial or complete obstruction. Signs of partial obstruction include choking with drooling, stridor, and the patient maintains the ability to speak. Signs of complete obstruction include choking with inability to speak or cough, and signs of respiratory distress such as cyanosis.
Foreign bodies above the larynx often present with stridor, while objects below the larynx present with wheezing. Foreign bodies above the vocal cords often present with difficulty and pain with swallowing and excessive drooling. Foreign bodies below the vocal cords often present with pain and difficulty with speaking and breathing. Increased respiratory rate may be the only sign of foreign body aspiration in a child who cannot verbalize or report if they have swallowed a foreign body.
If the foreign body does not cause a large degree of obstruction, patients may present with chronic cough, asymmetrical breath sounds on exam, or recurrent pneumonia of a specific lung lobe. The right lower lobe of the lung is the most common site of recurrent pneumonia in foreign body aspiration. This is due to the fact that the anatomy of the right main bronchus is wider and steeper than that of the left main bronchus, allowing objects to enter more easily than the left side.
Many complications can develop after a foreign body is removed, or if a foreign body remains in the airway. Patients may develop inflammation of the airway walls or lung abscess from a foreign body remaining in the airway. Hyperinflation of the airway distal to the obstruction can also occur if the foreign body is not removed. Patients can also develop pneumonia from retained foreign bodies. Episodes of recurrent pneumonia in the same lung field should prompt evaluation for a possible foreign body in the airway. Even if the foreign body is removed, complications such as chemical bronchitis, mucosal reactions, and the development of granulation tissue are possible.
Complications can also arise from interventions used to remove a foreign body from the airway. Rigid bronchoscopy is the gold standard for removal of a foreign body, however this intervention does have potential risks. The most common complication from rigid bronchoscopy is damage to the patient's teeth. Other less common complications include cuts to the mouth or esophagus, and damage to the vocal cords.
Most cases of foreign body aspiration are in children ages 6 months to 3 years due to the tendency for children to place small objects in the mouth and nose. Children of this age usually lack molars and cannot grind up food into small pieces for proper swallowing. Small, round objects including nuts, hard candy, popcorn kernels, beans, and berries are common causes of foreign body aspiration. Latex balloons are also a serious choking hazard in children that can result in death. A latex balloon will conform to the shape of the trachea, blocking the airway and making it difficult to expel with the Heimlich maneuver.
In adults, foreign body aspiration is most prevalent in populations with impaired swallowing mechanisms such as the following: neurological disorders, alcohol use, sedative use, advanced age (most common in the 6th decade of life), and loss of consciousness.
If foreign body aspiration is suspected, finger sweeping in the mouth is not recommended due to the increased risk of displacing the foreign object further into the airway.
Most patients receive a chest x-ray to determine the location of the foreign body. However, a negative chest x-ray cannot rule out foreign body aspiration. Lateral neck, chest, and bilateral decubitus end-expiratory chest x-rays should be obtained in patients suspected of having aspirated a foreign body. Signs on x-ray that can be indicative of foreign body aspiration include visualization of the foreign body or hyperinflation of the affected lung. Other x-ray findings that can be seen with foreign body aspiration include obstructive emphysema, atelectasis, and consolidation.
While, x-ray can be used to visualize the location and identity of a foreign body, rigid bronchoscopy under general anesthesia is the gold-standard for diagnosis since the foreign body can be visualized and removed with this intervention. Rigid bronchoscopy is indicated when two of the three following criteria are met: report of foreign body aspiration by the patient or a witness, abnormal lung exam findings, or abnormal chest x-ray findings.
Treatment of foreign body aspiration is determined by the severity of obstruction of the airway involved. In partial obstruction, the patient can usually clear the foreign body with coughing. In complete obstruction, acute intervention is required to remove the foreign body.
For choking children less than 1 year of age, the child should be placed face down over the rescuer's arm. Back blows should be delivered with the heel of the hand, then the patient should be turned face-up and chest thrusts should be administered. The rescuer should alternate five back blows followed by five chest thrusts until the object is cleared. The Heimlich maneuver should be used in choking patients older than 1 year of age to dislodge a foreign body.  If the patient becomes unresponsive during physical intervention, cardiopulmonary resuscitation (CPR) should be started.
In the event that the above measures do not remove the foreign body, and adequate ventilation cannot be restored, need for treatment by trained personnel becomes necessary. Laryngoscopy should be performed in unresponsive patients if non-invasive airway clearance techniques are unsuccessful. Laryngoscopy involves placing a device in the mouth to visualize the back of the airway. If the foreign body can be seen, it can be removed with forceps. An endotracheal tube should then be placed in order to prevent airway compromise from resulting inflammation after the procedure. If the foreign body cannot be visualized, intubation, tracheotomy, or needle cricothyrotomy can be done to restore an airway for patients who have become unresponsive due to airway compromise.
If non-invasive measures do not dislodge the foreign body, and the patient can maintain adequate ventilation, rigid bronchoscopy under general anesthesia should be performed. Supplemental oxygen, cardiac monitoring, and a pulse oximeter should be applied to the patient. Efforts should be made to keep the patient calm and avoid agitating the patient to prevent further airway compromise. After the foreign body is removed, patients should receive nebulized beta-adrenergic medication and chest physiotherapy to further protect the airway.
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