Atelectasis (Collapsed Lung Tissue)

What atelectasis is

Your lungs are made of millions of tiny air sacs. To stay open, they rely on air flowing in, regular deep breaths, and a soapy coating called surfactant that lowers surface tension. When any of these fail, sacs collapse. The collapsed area cannot exchange oxygen, so blood passes through without picking any up.

Atelectasis is a description, not a disease in itself. It can be tiny and linear (plate-like or discoid atelectasis), involve the lowest parts of both lungs (bibasilar atelectasis), or collapse a whole lobe or lung.

Types of atelectasis

Obstructive resorption atelectasis is the classic form after an airway blockage. Breathing high concentrations of oxygen can speed it up, because oxygen is absorbed faster than nitrogen.

Causes and risk factors

• Surgery and anesthesia: anesthesia relaxes the diaphragm and changes breathing. Pain afterward stops deep breaths and coughs. Atelectasis develops in most people having general anesthesia, though usually only in small areas.
• Mucus plugs: in cystic fibrosis, asthma, COPD, or after surgery when coughing is weak.
• Inhaled object: small toys, nuts or food in children. See foreign body aspiration.
• Tumors: a lung cancer growing inside an airway can collapse a lobe.
• Fluid or air around the lung: a pleural effusion or pneumothorax.
• Shallow breathing: from broken ribs, obesity, being bedbound, opioids, neuromuscular disease or a paralyzed diaphragm.
• Premature birth: lack of surfactant in newborn lungs.

Smoking, older age, obesity and existing lung disease all raise the risk after surgery.

Symptoms

Small areas often cause no symptoms and are found on an X-ray. Larger areas cause:

• shortness of breath and fast, shallow breathing
• low oxygen levels, sometimes with blue-tinged lips
• cough
• chest discomfort
• fever, especially if infection develops in the collapsed area

Symptoms of the underlying cause, such as wheezing with a foreign body or weight loss with a tumor, may also be present.

Diagnosis

• Examination: reduced breath sounds and dullness when the chest is tapped over the collapsed area.
• Pulse oximetry: checks oxygen levels.
• Chest X-ray: shows the collapsed area as a denser region, with nearby structures (the trachea, heart or diaphragm) pulled toward it.
• CT scan: shows the extent and helps find a cause such as a tumor or effusion.
• Bronchoscopy: a camera into the airways to find and remove a blockage or take a biopsy.
• Ultrasound: useful for pleural fluid and for bedside checks in intensive care.

Treatment

Treatment depends on the cause and size.

Re-expanding the lung

• Deep breathing and coughing: take slow deep breaths and hold them for a few seconds, several times an hour while awake after surgery.
• Incentive spirometer: a handheld device that shows how deeply you are breathing and encourages full breaths.
• Getting up and walking: as soon as it is safe after surgery.
• Good pain control: so deep breathing and coughing do not hurt too much.
• Chest physiotherapy: clapping, vibration and drainage positions loosen mucus.
• Positive pressure breathing: CPAP or other devices to hold airways open.

Treating the cause

• Bronchoscopy to remove a mucus plug or inhaled object.
• Draining fluid or air with a needle or chest tube.
• Treating a tumor with surgery, radiotherapy, stents or other cancer treatment.
• Medicines such as nebulized saline, airway-opening inhalers or, in cystic fibrosis, mucus-thinning treatments.
• Antibiotics if pneumonia develops in the collapsed area.

Complications

• Pneumonia in the collapsed segment, because mucus and bacteria are trapped
• Low oxygen levels (hypoxemia) and respiratory failure in large or bilateral collapse
• Bronchiectasis (permanently widened airways) if collapse lasts a long time

Outlook

Postoperative atelectasis usually resolves within days with breathing exercises and activity. Atelectasis caused by a blockage clears once the blockage is removed. When it is caused by scarring or an untreatable tumor, the collapse may be permanent.

Prevention

Before surgery, stop smoking (ideally at least 4 to 8 weeks beforehand) and ask about breathing exercises. After surgery, use your incentive spirometer, cough with a pillow pressed against any belly or chest wound, and get out of bed as soon as you are allowed. Keep small objects and hard foods like whole nuts away from young children.

Frequently asked questions

What is atelectasis?

Atelectasis is the collapse of part or all of a lung, so air sacs deflate and stop exchanging oxygen. It is common after surgery and can also be caused by airway blockages, fluid or air around the lung, or scarring. Small areas often cause no symptoms.

Is atelectasis serious?

Usually not. Small areas of atelectasis after surgery are very common and clear with deep breathing and movement. It becomes serious when a large area collapses, oxygen levels drop, pneumonia develops, or the cause is a tumor or blockage that needs treatment.

What is obstructive resorption atelectasis?

It is collapse caused by a blocked airway. Air trapped beyond the blockage is gradually absorbed into the bloodstream, and the air sacs collapse. Mucus plugs, inhaled objects and tumors are typical causes. Treatment is removing or bypassing the blockage.

What does bibasilar atelectasis mean?

Bibasilar atelectasis means small areas of collapse at the bases (bottoms) of both lungs. It is a common incidental finding on X-rays and CT scans, especially after surgery, in people who are lying down a lot, or with shallow breathing. It usually needs no treatment beyond deep breathing.

How long does atelectasis take to heal?

Atelectasis after surgery often improves within 24 to 72 hours of regular deep breathing and walking. Collapse caused by a blockage usually reopens quickly once the blockage is cleared. Collapse from scarring or long-term compression may not fully recover.