Basic airway anatomy and physiology:

Airway obstruction can occur at any level of the respiratory tract, and may be partial or complete.

 

The tongue is the most common cause of airway obstruction, which can occur in patients with reduced conscious level. A reduction in the normal tone of the muscles supporting the tongue, cause it to fall backwards and occlude the pharynx.

Obstructed airway

Unobstructed airway

Common causes of airway obstruction:

  1. Foreign object: Lodged in airway, more common in young children.

  2. Soft tissue swelling: Can be caused by infection, trauma, burns, inhalation injury or anaphylaxis.

  3. Reduced conscious level: Tongue may occlude the airway.

  4. Mass: From either an abscess or tumour.

  5. Secretions: In a patient with dysphagia or weak cough.

Signs of Partial Airway Obstruction:

  • Suggests secretions (sputum, blood, vomit) in the upper airway.

  • Occurs when the pharynx is partially obstructed by the tongue.

  • An abnormal, high pitched, musical sound caused by an obstruction at or above the larynx. Normally occurs on inspiration.

  • An abnormal deep, harsh voice. Can be due to irritation/ obstruction at laryngeal level.

  • Occurs due to mechanical obstruction such as foreign body.

Signs of Complete Airway Obstruction:

  • Due to no air movement.

  • Asynchronous 'see saw' movement of the chest and abdomen due to inspiratory effort.

  • Negative pressure generated in the chest pulls the soft tissue at the sternal notch inward.

  • Patient is likely to be agitated or drowsy.

  • Due to hypoxia, the mucous membranes develops a blue discolouration. Late sign.