Airway Obstruction

Etiology

Any pathology that compromises airflow from the nasopharynx and oropharynx to the lungs can cause upper airway obstruction. Often, etiologies that cause upper airway obstruction involve inflammation, infection, or trauma of the airway structures. An anatomic variant may also cause or contribute to obstruction. Causes of airway obstruction include deviated septum, foreign body ingestion, macroglossia, tracheal webs, tracheal atresia, retropharyngeal abscess, peritonsillar abscess, rhinitis, polyps, enlarged tonsils, lipoma of the neck, nasopharyngeal/oropharyngeal cancers, edema from epiglottitis, blunt or penetrating trauma, anaphylaxis, turbinate hypertrophy, and chemical or thermal burns. Obstructive sleep apnea is a medical condition that is a subset of sleep apnea and is considered a chronic cause of airway obstruction.[4]

Epidemiology

Most children who die from airway obstruction injuries are usually younger than four years of age. In adults, airway obstruction is more common with inflammation, infection, and trauma. Airway obstruction is a common cause of emergency department visits.[4]

History and Physical

In cases of acute obstruction of the airway, a history of the events leading to the obstruction may be critical to deciding the intervention necessary to alleviate the potentially life-threatening symptoms. Often, secondary to the obstruction, the patient may be unable to give this history, and health care providers may have to rely on family or bystanders for pertinent history. Making a diagnosis of airway obstruction requires a thorough exam of the head and neck. Patients with acute obstruction, such as foreign body ingestion, trauma, or anaphylaxis, provide an acute challenge to the healthcare provider because these often require rapid diagnosis and intervention. These patients often present with acute distress, altered mentation, and other signs of inability to move air. Patients may also present in an obtunded state or cardiopulmonary arrest. The physical exam should be focused on finding correctable sources of obstruction, especially in patients in acute distress. Nasal passages should be inspected, as well as the oropharynx. The neck should be examined entirely for pathology that may be causing external compression on airway structures. Patients with obstructive sleep apnea may present with obesity and a wide and short neck. Often the tongue may be large, and the mandible may be small. Adjuncts to the physical exam include nasal speculum with a light source, rigid or flexible endoscopy, and direct laryngoscopy.

Evaluation

In cases of acute upper airway obstruction, evaluation should be prompt, and the provider should be prepared to proceed to intervention with limited delay. All necessary airway equipment should be made available at the time of evaluation in case immediate intervention is required. The nasopharyngeal area may be evaluated with a flexible or rigid endoscope. Direct laryngoscopy is another tool that may also be helpful not only for diagnosis but also in case of intervention. Imaging techniques are available, but extreme caution should be utilized in patients with an acute obstruction or chronic obstruction with acute distress. Obtaining imaging should not delay the correction of obstruction in patients in acute distress. In these cases, imaging may be helpful in determining etiology after the obstruction has been alleviated. Imaging modalities that are used to assess airway obstruction include the lateral head and neck x-rays, CT scans, and MRI. CT scans produce images that can assess both bony structures and soft tissues. The airway diameter can be evaluated, as well. The latest CT scans are fast and can create three-dimensional images. Again caution must be undertaken when deciding if the patient is stable for such diagnostic testing. MRI can also be quite helpful in determining the etiology of airway obstruction. MRI is of particular benefit when evaluating soft tissue masses and surrounding structures. Besides generating three-dimensional images, MRI does not produce radiation, and dye is not always used. The limitations of MRI are availability and cost.[5][6]

Treatment / Management

The immediate goal in the management of patients with airway obstruction is relieving the obstruction, so air exchange (oxygenation and ventilation) can proceed. In an acute obstruction of the airway, this may be critical because if left uncorrected, obstruction is often fatal in a matter of minutes. Correction of airway obstruction may be achieved by correcting the underlying pathology, but also may require intervention that alleviates the obstruction without correcting the underlying pathology, especially in urgent cases. When preparing to treat a patient with potential acute airway obstruction, all anticipated equipment and personnel should be available as soon as possible. This includes airway supplies for nasotracheal and endotracheal intubation, as well as, surgical airway equipment. Experts in airway management should be sought out as available. These may include anesthesia providers, emergency medicine providers, respiratory therapists, and critical care providers. Surgical consultation for possible surgical airway should be considered before the need for surgical airway arises. Additional equipment that might be of benefit in a difficult airway situation such as a bronchoscope should also be obtained as soon as possible. Supplemental oxygen should be provided to the patient and attempts to reposition the patient, such as a chin lift and jaw thrust maneuver, should be undertaken. Cervical spine precautions should be observed in patients believed to be involved in trauma leading to their airway compromise. Immediate and definitive relief of obstruction may include removal of foreign body, nasotracheal intubation, endotracheal intubation, tracheostomy, or cricothyroidotomy. Additional procedures such as jet insufflation may provide temporary relief. Efforts to treat the underlying cause of the obstruction should also be considered. In cases of infectious etiology, these should be treated with appropriate antibiotics and surgical drainage when indicated. In the case of obstructing masses, these may be worked up after the airway is secured, and proper surgical consultation should be obtained. In more chronic causes such as obstructive sleep apnea, diagnostic studies should be performed, and patients may require intervention while sleeping and possible surgery.[7][8]

Differential Diagnosis

The differential diagnosis of acute upper airway obstruction:

• Aspiration
• Infection
• Hemorrhage
• Angioedema
• Iatrogenic (e.g., post-surgical, instrumental)
• Blunt trauma
• Inhalation injury
• Neuromuscular disease

The differential diagnosis of chronic airway obstruction:

• Infection
• Post-intubation
• Amyloidosis
• Sarcoidosis
• Tumor
• Collagen vascular disease
• Mediastinal mass
• Esophageal tumor
• Cardiovascular anomaly
• Neuromuscular disease
• Idiopathic
• Tonsillar enlargement in children

Prognosis

The prognosis of airway obstruction depends on the etiology of the condition. Generally, the prognosis of inflammatory and infectious causes is more favorable than that of malignancy.

Complications

The complications of airway obstruction are:

• Respiratory failure
• Arrhythmias
• Cardiac arrest
• Death