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Atelectasis is a condition in which one or more areas of your lungs collapse or don't inflate properly. NIH - National Heart, Lung, and Blood Institute

About Atelectasis

Atelectasis (at-uh-LEK-tuh-sis) is a condition in which one or more areas of your lungs collapse or don't inflate properly. If only a small area or a few small areas of lung are affected, you may have no signs or symptoms.

If a large area or several large areas of lung are affected, they may not be able to deliver enough oxygen to your blood. This can cause symptoms and complications.


To understand atelectasis, it helps to understand how the lungs work. Your lungs are organs in your chest that allow your body to take in oxygen from the air. They also help remove carbon dioxide (a waste gas that can be toxic) from your body.

When you breathe, air passes through your nose and mouth into your windpipe. The air then travels to your lungs' air sacs. These sacs are called alveoli (al-VEE-uhl-eye).

Small blood vessels called capillaries (KAP-ih-lare-ees) run through the walls of the air... Read more about Atelectasis

What works? Research summarized

Evidence reviews

Dornase alfa for non-cystic fibrosis pediatric pulmonary atelectasis

OBJECTIVE: To review the literature evaluating the efficacy of dornase alfa for non-cystic fibrosis pediatric patients with pulmonary atelectasis.

Respiratory physiotherapy to prevent pulmonary complications after abdominal surgery: a systematic review

The authors concluded that current evidence does not appear to justify routine prophylactic respiratory physiotherapy after abdominal surgery. The quality of the primary studies was suboptimal and the review had some limitations with respect to the search and the reported study selection process. However, the review was generally well-conducted and these conclusions seem likely to be reliable.

[Supplemental oxygen for the prevention of postoperative nausea and vomiting: a meta-analysis of randomized clinical trials]

OBJECTIVE: Despite the development of antiemetic drugs, the incidence of postoperative nausea and vomiting remains between 20% and 30%. This meta-analysis examines the hypothesis that perioperative administration of supplemental oxygen reduces the incidence of these complications.

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Summaries for consumers

Applying positive pressure at the end of each breath during anaesthesia for prevention of mortality and postoperative pulmonary complications

We reviewed the evidence on the effects of positive end‐expiratory pressure (PEEP) during general anaesthesia in adult patients 16 years of age and older.

Preoperative physical therapy for elective cardiac surgery patients

Patients undergoing cardiac surgery are at risk of postoperative pulmonary complications such as pneumonia. These complications prolong postoperative recovery and may even lead to death. Increased physical fitness improves people's functional capacity, including their lungs, and could result in individuals being better prepared to withstand the consequences of the physical stress of surgery.

Is continuous positive airway pressure (CPAP) during the postoperative period useful?

General anaesthesia can lead to reduced lung volumes and collapse of the alveoli as well as to reversible, patchy collapse of areas of lung (atelectasis) and subsequent low oxygenation. These problems are worse in those patients undergoing upper abdominal surgery, in those who have predisposing factors such as obesity and chronic lung disease and in smokers. Continuous positive airway pressure (CPAP) is a type of therapy that uses a high‐pressure gas source to deliver constant pressure to the airways throughout both inspiration and expiration in spontaneously breathing people; oxygen is added in appropriate amounts. CPAP uses a variety of masks, which are placed over the nose or mouth. The aim of this technique is to improve the oxygenation of patients while preventing common postoperative complications in vulnerable people, especially smokers and the obese.

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More about Atelectasis

Photo of an adult

Also called: Collapsed lung, Partial lung collapse

Other terms to know:

Related articles:
How the Lungs Work

Keep up with systematic reviews on Atelectasis:


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