(Collapsed Lung)


Atelectasis is a collapse of the air sacs in the lungs. It may occur in part or all of the lung. It can make breathing difficult.

The Lungs (Cut-away View)

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Atelectasis is caused by:

  • A blocked airway, such as from a foreign body, mucus plug, or tumor
  • Pressure outside the airway, such as from:
    • Injury
    • Scarring
    • Fluid buildup
    • Infection
  • Suppressed breathing or coughing
  • Reduced surfactant—a fluid that keeps the lungs expanded

Risk Factors

Things that may raise the risk of atelectasis are:


Atelectasis may or may not cause symptoms. A larger area of collapse is more apt to cause symptoms. In this case, symptoms may be:

  • Breathing that is fast, difficult, or shallow
  • Coughing
  • Mild fever
  • Fast heart rate
  • Chest pain
  • Blueness of the lips or nails


The doctor will ask about your symptoms and health history. A physical exam will be done. This may include listening to the lungs for changes in the normal sounds.

The airways may be viewed with:

Other tests may be needed to confirm or rule out the cause of atelectasis.


The goal is to treat the underlying cause and maintain enough oxygen. The collapsed lung usually expands once the cause has been corrected. Mild atelectasis often goes away on its own without treatment.

Treatments options may be:

  • Physical therapy—to help clear mucus from the lung
  • Respiratory therapy, such as:
    • Breathing masks or treatments—to keep the airway open
    • Incentive spirometry—to promote deep breathing
    • Suction—to help remove fluid and mucus build up
    • Mechanical ventilation—if the person is unable to breathe on their own
  • Oxygen—to assist with breathing
  • Medicines to:
    • Open airways
    • Treat the condition that caused atelectasis
    • Fight infections
  • Bronchoscopy—to remove a foreign body or mucus that is blocking the airway


To help lower the risk of atelectasis:

  • After surgery:
    • Follow instructions for deep breathing, coughing, and turning.
    • Use pain medicines, if needed.
  • Quit smoking
  • Lose weight.
  • Follow treatment for lung or heart problems.


American Lung Association
National Heart, Lung, and Blood Institute


The Lung Association


Atelectasis. Merck Manual Professional Version website. Available at:
...(Click grey area to select URL)
Accessed March 30, 2021.
Chest x-ray patterns in the differential diagnosis of lung disorders. EBSCO DynaMed website. Available at: Accessed March 30, 2021.
Explore atelectasis. National Heart, Lung, and Blood Institute website. Available at: Accessed March 30, 2021.
Marini JJ. Acute lobar atelectasis. Chest. 2019;155(5):1049-1058.
Last reviewed December 2020 by EBSCO Medical Review Board David L. Horn, MD, FACP
Last Updated: 3/30/2021

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