Atelectasis

Overview

Atelectasis (at-uh-LEK-tuh-sis) is a complete or partial collapse of the entire lung or area (lobe) of the lung. It occurs when the tiny air sacs (alveoli) within the lung become deflated or possibly filled with alveolar fluid.

Atelectasis is one of the most common breathing (respiratory) complications after surgery. It's also a possible complication of other respiratory problems, including cystic fibrosis, lung tumors, chest injuries, fluid in the lung and respiratory weakness. You may develop atelectasis if you breathe in a foreign object.

Atelectasis can make breathing difficult, particularly if you already have lung disease. Treatment depends on the cause and severity of the collapse.

Symptoms

There may be no obvious signs or symptoms of atelectasis. If you do have signs and symptoms, they may include:

• Difficulty breathing
• Rapid, shallow breathing
• Wheezing
• Cough

When to see a doctor

Always seek medical attention right away if you have trouble breathing. Other conditions besides atelectasis can cause breathing difficulties and require an accurate diagnosis and prompt treatment. If your breathing becomes increasingly difficult, seek emergency medical help.

Causes

Atelectasis occurs from a blocked airway (obstructive) or pressure from outside the lung (nonobstructive).

General anesthesia is a common cause of atelectasis. It changes your regular pattern of breathing and affects the exchange of lung gases, which can cause the air sacs (alveoli) to deflate. Nearly everyone who has major surgery develops some amount of atelectasis. It often occurs after heart bypass surgery.

Obstructive atelectasis may be caused by many things, including:

• Mucus plug. A mucus plug is a buildup of mucus in your airways. It commonly occurs during and after surgery because you can't cough. Drugs given during surgery make you breathe less deeply, so normal secretions collect in the airways. Suctioning the lungs during surgery helps clear them, but sometimes they still build up. Mucus plugs are also common in children, people with cystic fibrosis and during severe asthma attacks.
• Foreign body. Atelectasis is common in children who have inhaled an object, such as a peanut or small toy part, into their lungs.
• Tumor inside the airway. An abnormal growth can narrow the airway.

Possible causes of nonobstructive atelectasis include:

• Injury. Chest trauma — from a fall or car accident, for example — can cause you to avoid taking deep breaths (due to the pain), which can result in compression of your lungs.
• Pleural effusion. This condition involves the buildup of fluid between the tissues (pleura) that line the lungs and the inside of the chest wall.
• Pneumonia. Various types of pneumonia, a lung infection, can cause atelectasis.
• Pneumothorax. Air leaks into the space between your lungs and chest wall, indirectly causing some or all of a lung to collapse.
• Scarring of lung tissue. Scarring could be caused by injury, lung disease or surgery.
• Tumor. A large tumor can press against and deflate the lung, as opposed to blocking the air passages.

Risk factors

Factors that make you more likely to develop atelectasis include:

• Older age
• Any condition that makes it difficult to swallow
• Confinement to bed with infrequent changes of position
• Lung disease, such as asthma, COPD, bronchiectasis or cystic fibrosis
• Recent abdominal or chest surgery
• Recent general anesthesia
• Weak breathing (respiratory) muscles due to muscular dystrophy, spinal cord injury or another neuromuscular condition
• Medications that may cause shallow breathing
• Pain or injury that may make it painful to cough or cause shallow breathing, including stomach pain or rib fracture
• Smoking

Complications

A small area of atelectasis, especially in an adult, usually is treatable. The following complications may result from atelectasis:

• Low blood oxygen (hypoxemia). Atelectasis makes it more difficult for your lungs to get oxygen to the air sacs (alveoli).
• Pneumonia. Your risk for pneumonia continues until the atelectasis goes away. Mucus in a collapsed lung may lead to infection.
• Respiratory failure. Loss of a lobe or a whole lung, particularly in an infant or in someone with lung disease, can be life-threatening.

Prevention

Atelectasis in children is often caused by a blockage in the airway. To decrease atelectasis risk, keep small objects out of reach of children.

In adults, atelectasis most commonly occurs after major surgery. If you're scheduled for surgery, talk with your doctor about strategies to reduce your risk. Some research suggests that certain breathing exercises and muscle training may lower the risk of atelectasis after certain surgeries.