Airway obstruction: Clinical sciences

An airway obstruction is defined as the inability to move air, or ventilate, from a direct occlusion or anatomic narrowing. It requires an immediate assessment and swift intervention, since it can be fatal if left untreated. There are many causes that can lead to airway obstruction, including trauma, tracheal narrowing, foreign body aspiration, mucus plugging, malignancy, and deep neck infection. Keep in mind that all of these causes have the potential to cause hemodynamic instability due to respiratory failure, especially trauma and foreign body aspiration.

When assessing a patient with signs and symptoms suggestive of airway obstruction, you should first perform an ABCDE assessment to determine if the patient is unstable or stable. Be sure to look for red flags of impending airway compromise like stridor, tachypnea, accessory muscle use like gasping or nostril flaring, as well as bleeding in the nasopharynx or the oropharynx, large or expanding neck hematoma, crepitus in the neck or upper chest, and tracheal deviation.

If the patient is unstable with red flags, you must initiate acute management right away to stabilize their airway, breathing, and circulation. The goal here is to maintain oxygenation above 90% initially with a high-flow nasal cannula or non-rebreather. However, if the patient desaturates or cannot protect their airway, proceed with rapid sequence intubation. This involves administering an induction agent like etomidate; and a paralytic agent like succinylcholine or rocuronium. Once medications start working, you can intubate the patient.

Here’s a clinical pearl! If airway obstruction is anticipated, make sure to have multiple sizes of small endotracheal tubes available. Keep in mind that, although securing the airway is the top priority, the workup will likely require laryngoscopy and bronchoscopy.

Now, if intubation is unsuccessful after 3 attempts or you cannot maintain oxygenation above 90%, consider cricothyroidotomy to create an emergency surgical airway. Once you’re done securing the airway, make sure to establish IV access and administer fluids before continuing with your assessment.

After acute management is initiated, obtain focused history and physical examination. If your patient is intubated, you may need to obtain history from family members or paramedics. Be sure to ask about any head, face, or neck trauma, changes in levels of consciousness, and presence of dyspnea prior to presentation. On physical exam, look for any signs of maxillofacial, neck, and chest injuries.

If you suspect trauma-induced airway obstruction, obtain a chest x-ray. Now, sometimes it might show associated injuries like pneumothorax, tracheal deviation, pneumomediastinum, or rib fractures. However, in some cases, the x-ray will be completely normal. Even though it is normal, the patient is still having a traumatic airway obstruction from a tracheal crush injury, so you need to move on to management. Keep in mind that subcutaneous emphysema and mediastinal air will not cause airway obstruction, since the cartilage in the trachea is stronger than the air pressure.

Once the diagnosis of traumatic airway obstruction is confirmed, your next step is to establish a secure or definitive airway. You can use high-flow oxygen or a bag-valve mask to provide oxygen. Now, in some patients, like the ones with maxillofacial trauma, bag-valves are contraindicated. If they are not already intubated, consider rapid sequence intubation and possibly a surgical airway like cricothyroidotomy or tracheostomy. On the other hand, if the patient has supraglottic injuries, you can skip the intubation and go directly to securing a surgical airway. Keep in mind, if the airway obstruction is distal in the trachea, a surgical airway will not help relieve the obstruction. Lastly, once the patient is able to maintain oxygenation above 90% and no longer has signs of impending airway compromise, continue observing them.

Okay, now that unstable patients are taken care of, let’s talk about stable patients. Your first step here is to obtain a focused history and physical examination. Alright, let’s start with tracheal narrowing. This can occur with tracheal stenosis or tracheomalacia. Tracheal stenosis is most often a scar tissue that develops as a complication of endotracheal intubation or tracheostomy; while tracheomalacia is a tracheal weakness and collapse, which can be congenital or acquired as a complication of endotracheal intubation or tracheostomy.

Now, your patient might report dyspnea, as well as persistent cough, sputum retention, and frequent respiratory infections. Additionally, some patients may have a history of prior endotracheal intubation or tracheostomy. On a physical exam, you might notice tachypnea, wheezing, or stridor.

At this point you can suspect tracheal narrowing, so your next step is to confirm the diagnosis. To do this, order a chest x-ray, neck and chest CT, and a bronchoscopy. The chest x-ray may show the airway narrowing, but can also often be normal; however, it is still useful to establish a baseline evaluation of the lungs and rule out other conditions. Next, neck and chest CT allows you to assess the location, approximate length, and severity of the narrowing. Lastly, the gold standard is bronchoscopy, since it allows direct visualization of the narrowing to confirm the diagnosis.

Once confirmed, mild asymptomatic cases usually don’t need treatment other than observation. On the flip side, severe or symptomatic cases require treatment to restore airway patency, either with local bronchoscopic therapy or with surgery.

Let’s go back to H&P and talk about a different presentation. The patient might report chest pain, hemoptysis, and recurrent pneumonia. On physical exam, if you find wheezing and unilateral decreased breath sounds, you should be suspicious of a foreign body obstruction. This is more common in children, but also among older adults with stroke-related dysphagia, Alzheimer, or Parkinson disease, as they are at an increased risk for aspiration.