Respiratory Distress

Respiratory Distress


There are many symptoms and findings that are associated with patients in respiratory distress. Here are a few important ones:1

  • Dyspnea is a subjective feeling of difficult, labored, or uncomfortable breathing, which patients often describe as “shortness of breath”, “breathlessness”, or “not getting enough air”.
    • Differentiating between cardiac and pulmonary causes of dyspnea is one of the most important, and frequently most difficult tasks, an emergency physician faces.
  • Hypoxia is insufficient delivery of oxygen to the tissues.
    • Tissue hypoxia occurs in states of low cardiac output, low Hb concentration, or low SaO2.
  • Hypoxemia is an abnormally low arterial oxygen tension.
    • Hypoxemia is arbitrarily defined as a PaO2 < 60 mmHg.
  • Hypercapnia is exclusively caused by alveolar hyperventilation and is arbitrarily defined as a PaCO2 >45 mmHg.
  • Cyanosis is a bluish color of the skin and mucous membranes that results from increased amount of reduced Hb (deoxyhemoglobin) or Hb derivatives.


“Causes of respiratory distress are multifactorial and include the findings of dyspnea, hypoxia, hypercapnia, and cyanosis. Despite the increasing reliance on ancillary studies and technology, the evaluation of respiratory distress depends on a careful history and physical examination.”Patients with an increased respiratory rate can be an indicative symptom of respiratory distress and therefore having an approach to tachypnea is a key essential. 


Specific approaches to different etiologies of respiratory distress can be found throughout the “Pulmonary” parent section. An in-depth review of many specific aspects of Respiratory Emergencies can be found in this excellent two-part Respiratory Module (AIR Series Part 1 and Part 2)


Click HERE for a list of all mentioned FOAM resources.


  1. Sarko, J., Stapczynski, S., Chapter 65, “Respiratory Distress”. Tintinalli’s Emergency Medicine – A Comprehensive Study Guide. J Tintinalli. 7th ed. McGraw-Hill Education, 2010. 
  2. Hargraves, J., Chapter 29, “Respiratory Distress”. Tintinalli’s Emergency Medicine Manual. Cline et al. McGraw-Hill Medical. 2012. 319.


Prepared by Alex Mungham PGY1 FM – University of Ottawa