Home Pathophysiology Respiratory Failure Pathophysiology and Schematic Diagram

Respiratory Failure Pathophysiology and Schematic Diagram


The respiratory system is responsible for ventilation and gas exchange in order to deliver oxygen into the respiratory-failurebloodstream and collection of waste gases such as carbon dioxide. In works hand in hand especially with the cardiovascular system to achieve ventilation and perfusion.


Ventilation is the movement of air in and out of the lungs. During inspiration, air flows form the environment into the trachea, bronchi bronchioles and alveoli. During expiration, alveolar gas travels the same route in reverse (Smeltzer, et al., 2010).


Respiration is the process in which gas exchange between the atmospheric air and the blood and between the blood and the cells of the body take place.

What is respiratory failure?

Respiratory failure is a syndrome wherein the lungs fail to provide adequate oxygenation or ventilation in the blood. It is a life-threatening deterioration of the gas exchange function of the lungs which leads to hypoxemia and hypercapnia.

What are the types of respiratory failure?

Respiratory failure is classified as either hypoxemic respiratory failure (type I) or hypercapnic respiratory failure (type II).

  • Hypoxemic respiratory failure (type I) is characterized by an arterial oxygen tension (PaO₂) lower than 60 mm Hg with a normal or low arterial carbon dioxide tension (PaCO₂).
  • Hypercapnic respiratory failure (type II) is characterized by a PaCO₂ higher than 50 mm Hg.

It may be further classified into acute and chronic respiratory failure.

  • Acute respiratory failure is defined as a decrease in arterial oxygen tension (PaO₂) to less than 50 mmHg (hypoxemia) and an increase in arterial carbon dioxide tension (PaCO₂) with greater than 50 mmHg (hypercapnia), with an arterial pH less than 7.35.
  • Chronic respiratory failure is defined as deterioration in the gas exchange function of the lung that has developed insidiously or has persisted for a long period after an episode of acute respiratory failure (Smeltzer, et al., 2010).

Medical Management

The objectives of treatment are to correct the underlying cause and to restore adequate gas exchange in the lung (Smeltzer, et al., 2010).

Nursing Interventions

Assessment of the following:

  • Patient’s level of response
  • Arterial blood gases
  • Pulse oximetry
  • Vital signs

Position the patient in high Fowler’s position.
Administer oxygen to maintain the PaO₂ level greater than 60 to 70 mmhg.
Encourage deep breathing exercises.
Administer medications as prescribed (i.e. bronchodilators).
Prepare patient for possible mechanical ventilation if supplemental oxygen cannot maintain acceptable PaO₂ levels.

Respiratory Failure Pathophysiology and Schematic Diagram


  • Kaynar, A.M. (n.d.) Respiratory Failure. Retrieved from http://emedicine.medscape.com/article/167981.
  •  Silvestri, L. A.(2005). Saunders Comprehensive review for the NCLEX-RN Examination. St. Louis, Mo.: Saunders/Elsevier Inc.
  • Smeltzer, S., Bare, B., Hinkle, J. Cheever, K. (2010). Brunner & Suddarth’s Textbook of Medical Surgical Nursing.Wolter Kluwer Health/ Lippincott Williams & Wilkins.


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