THE CLINICAL CHALLENGE
The upper airway refers to that portion of the airway anatomy that extends from the lips and nares down to the first tracheal ring. The first portion of the upper airway is redundant: a nasal pathway and an oral pathway. However, at the level of the oropharynx, the two pathways merge, and this redundancy is lost. The most common life-threatening causes of acute upper airway distortion and obstruction occur in the region of this common channel, and they are typically laryngeal. In addition, disorders of the base of the tongue and the pharynx can cause obstruction (Box 36-1). This chapter deals with problems that distort or obstruct the upper airway. Foreign bodies in the upper airway are addressed in Chapters 27 and 41.
Causes of upper airway obstruction.
A. Infectious
a. Viral and bacterial laryngotracheobronchitis (e.g., croup)
b. Parapharyngeal and retropharyngeal abscesses
c. Lingual tonsillitis (a lingual tonsil is a rare but real congenital anomaly and a well-recognized cause of failed intubation)
d. Infections, hematomas, or abscesses of the tongue or floor of the mouth (e.g., Ludwig angina)
e. Epiglottitis (also known as supraglottitis)
B. Neoplastic
a. Laryngeal carcinomas
b. Hypopharyngeal and lingual (tongue) carcinomas
C. Physical and chemical agents
a. Foreign bodies
b. Thermal injuries (heat and cold)
c. Caustic injuries (acids and alkalis)
d. Inhaled toxins
D. Allergic/idiopathic: including ACEI-induced angioedema
E. Traumatic: blunt and penetrating neck and upper airway trauma
APPROACH TO THE AIRWAY
The signs of upper airway distortion and obstruction may be occult or subtle. Life-threatening deterioration may occur suddenly and unexpectedly. Seemingly innocuous interventions, such as small doses of sedative hypnotic agents to alleviate anxiety or the use of topical local anesthetic agents, may precipitate sudden and total airway obstruction. Rescue devices may not be successful and may even be contraindicated in some circumstances. The goal in patients with upper airway obstruction or distorted upper airway anatomy is to manage the airway in a rapid yet controlled fashion before complete airway obstruction occurs.
When Should an Intervention Be Performed?
Chapter 1 deals with the important question of when to intubate. If airway obstruction is severe, progressive, or imminent, then immediate action (often “forced-to-act” rapid sequence intubation [RSI] or cricothyrotomy) is required without further consideration of transferring the patient to another venue (e.g., the operating room or another hospital). It is critical to recognize patients who require an inevitable surgical airway and to perform the procedure without delay, as valuable time is often used up trying other methods to obtain airway control. Failing an indication for an immediate intervention, the question becomes more nuanced: What is the expected clinical course?
Penetrating wounds to the neck and airway are notoriously unpredictable (see Chapter 33). Some experts advocate for securing the airway regardless of warning signs, whereas others advocate expectant observation. There are substantial problems with the latter strategy. The first is that the patient often remains relatively asymptomatic until they suddenly and unexpectedly develop total obstruction, resulting in an airway (and patient) that cannot be rescued. The second is that unless a flexible endoscope is used, the observer is only able to see the anterior portion of the airway and not the posterior and inferior parts where the obstruction will likely occur. In other words, when not using a flexible endoscope, one sees only “the tip of the iceberg.”
The time course of the airway threat is also important. All other things being equal, a patient who presents with airway swelling, such as angioedema, which has developed over 8 to 12 hours, is at substantially less risk for sudden obstruction than a similar patient where the same degree of swelling has developed over 30 minutes. Overall, for any condition in which the obstruction may be rapidly progressive, silent, and unobservable externally (e.g., angioedema, vascular injuries in the neck, and epiglottitis), acting earlier rather than later to secure the airway is the most prudent course.
There are four cardinal signs of acute upper airway obstruction:
•
Full access? Get Clinical Tree
