Atelectasis is a collapse of the air sacs in the lungs called alveoli. It may occur in a portion of the lung, or in the entire lung. Normally, oxygen enters the body through the lungs and is exchanged with carbon dioxide in the alveoli. The lungs expand and contract to create the exchange of these gases.

Atelectasis is not a disease, but a condition or sign that results from disease or abnormalities in the lungs.

The Lungs (Cut-away View)
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Atelectasis is caused by:

  • Compression or blockage of the airway, such as by a foreign body, tumor, scarring, or mucous plug
  • Surpressed breathing or coughing
  • Periods of inactivity, especially in those who are obese
  • Reduced amount of surfactant, a liquid that keeps the lungs expanded

Risk Factors

Factors that may increase your chances of atelectasis:

  • Premature birth if lungs are not fully developed
  • Anesthesia
  • Restricted chest movement due to bone or muscle problems, or recent abdominal surgery
  • Injuries
  • Prolonged bed rest with few changes in position
  • Mechanical ventilation
  • Lung diseases, such as asthma, cystic fibrosis, or lung cancer
  • Weakened respiratory muscles
  • Smoking
  • Heart failure
  • Obesity
  • Conditions that limit physical activity such as a stroke, spinal cord injury, heart problems, trauma, or severe illness


Atelectasis may or may not cause symptoms. Small areas of collapse are less likely than larger areas to cause symptoms. Major atelectasis decreases the amount of oxygen available throughout the body.

Symptoms that may occur if a large area has collapsed include:

  • Rapid breathing
  • Shortness of breath
  • Taking shallow breaths
  • Coughing
  • Mild fever
  • Rapid heart rate
  • Chest pain
  • Blueness of the lips or nails


You will be asked about your symptoms and medical history. A physical exam will be done. This may include listening to your lungs for changes in the normal sounds.

Your body structures may need to be viewed. This can be done with:

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


Treatment focuses on treating the underlying cause and maintaining enough oxygen. The collapsed lung usually expands after the underlying cause has been corrected. Mild atelectasis often goes away on its own without treatment.

Treatments include:

Physical Therapy

The therapist uses different techniques to help clear mucus from the lung. You will be positioned so that gravity helps secretions flow out of the body. When resting in bed, lie on the unaffected side to promote drainage from the lung area that has collapsed. Moving around will also help clear your lungs.

Respiratory Therapy

Respiratory therapy may include any or all of the following:

  • Breathing masks or treatments to help keep your airways open
  • Incentive spirometry to promote deep breathing
  • Suction to help remove secretions
  • Mechanical ventilation if you are unable to breathe adequately on your own


Your doctor may recommend:

  • Medications to open the airways
  • Medications or therapy to treat the health condition that caused the collapse
  • Antibiotics to treat certain kinds of infection
  • Oxygen, if you are having trouble breathing


Bronchoscopy may be used to remove a foreign body or mucus that is blocking the airway.


To help reduce your chances of atelectasis:

  • After surgery, follow instructions for deep breathing, coughing, and turning. Ask for pain medication if discomfort is limiting movement or coughing.
  • If you smoke, talk to your doctor about ways to quit.
  • If you need to, talk to your doctor about the best ways to lose weight.
  • If you have a chronic lung or heart condition, follow the treatment plan outlined by your doctor.

American Lung Association

National Heart, Lung, and Blood Institute


Health Canada

The Lung Association


Atelectasis. Merck Manual Professional Version website. Available at: Updated July 2014. Accessed December 11, 2017.

Explore atelectasis. National Heart, Lung, and Blood Institute website. Available at: Updated January 13, 2012. Accessed December 11, 2017.

Last reviewed November 2018 by EBSCO Medical Review Board David L. Horn, MD, FACP  Last Updated: 11/24/2015