Atelectasis (at-uh-LEK-tuh-sis) — a complete or partial collapse of a lung or lobe of a lung — develops when the tiny air sacs (alveoli) within the lung become deflated. It's a breathing (respiratory) complication after surgery.

Atelectasis is also a possible complication of other respiratory problems, including cystic fibrosis, inhaled foreign objects, lung tumors, fluid in the lung, respiratory weakness and chest injuries.

The amount of lung tissue involved in atelectasis is variable, depending on the cause. Atelectasis can make breathing difficult and lower oxygen particularly if lung disease is already present. Treatment depends on the cause and severity of the collapse.

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

  • Difficulty breathing (dyspnea)
  • Rapid, shallow breathing
  • Coughing

When to see a doctor

Atelectasis is likely to occur when you're already in a hospital. However, 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 care.

Atelectasis may be the result of a blocked airway (obstructive) or of pressure from outside the lung (nonobstructive).

Almost everyone who has surgery has some atelectasis from anesthesia. Anesthesia changes your regular pattern of breathing and the absorption of gases and pressures, which may combine to cause some degree of collapse of the tiny air sacs (alveoli) in your lungs. Atelectasis is particularly prominent after heart bypass surgery.

Obstructive atelectasis may be caused by:

  • Mucus plug. Accumulation of mucus in your airways, often occurring during and after surgery because you can't cough, is a common cause of atelectasis. Drugs given during surgery make the lungs inflate less fully than usual, so normal secretions collect in the airways. Suctioning the lungs during surgery helps clear away these secretions, but they may continue to build up afterward. Mucus plugs also are 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.
  • Narrowing of major airways from disease. Chronic infections, including fungal infections, tuberculosis and other diseases, can scar and constrict major airways.
  • Tumor in a major airway. An abnormal growth can narrow the airway.
  • Blood clot. This occurs only if there's significant bleeding into the lungs that can't be coughed out.

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 is a buildup of fluid between the tissues (pleura) that line the lungs and the inside of the chest wall.
  • Pneumonia. Different types of pneumonia, an infection of your lungs, may temporarily 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. In these rare cases, the atelectasis is minor compared with the damage to the lung tissue from the scarring.
  • Tumor. A large tumor can press against and deflate the lung, as opposed to blocking the air passages.

Factors that increase the risk of atelectasis include:

  • Age — being younger than 3 or older than 60 years of age.
  • Any condition that interferes with spontaneous coughing, yawning and sighing.
  • Confinement to bed with infrequent changes of position.
  • Impaired swallowing function, particularly in older adults — aspirating secretions into the lungs is a major source of infections.
  • Lung disease, such as asthma in children, COPD, bronchiectasis or cystic fibrosis.
  • Premature birth.
  • Recent abdominal or chest surgery.
  • Recent general anesthesia.
  • Respiratory muscle weakness, due to muscular dystrophy, spinal cord injury or another neuromuscular condition.
  • Any cause of shallow breathing — including medications and their side effects, or mechanical limitations, such as abdominal pain or rib fracture, for example.

The following complications may result from atelectasis:

  • Low blood oxygen (hypoxemia). Atelectasis hampers your lungs' ability to get oxygen to the alveoli.
  • Pneumonia. You're at greater risk of developing pneumonia until the atelectasis has been cleared. Mucus in a collapsed lung may lead to infection.
  • Respiratory failure. A small area of atelectasis, especially in an adult, usually is treatable. But loss of a lobe or a whole lung, particularly in an infant or in someone with lung disease, can be life-threatening.

Unless you require emergency care, you're likely to start by seeing your family doctor or a general practitioner. However, in some cases when you call to set up an appointment, you may be referred immediately to a lung specialist (pulmonologist).

Here's some information to help you prepare for your appointment.

What you can do

  • Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
  • Recall when symptoms began and what you were doing at the time. Ask young children in a nonthreatening way about things they have put in their mouths.
  • Make a list of all medications, vitamins or supplements you're taking. Some medications, such as antihistamines, can make your secretions thicker and more difficult to cough out.
  • Bring a sample of your sputum in a small container.
  • Take a family member or friend along, if possible, to help you remember everything that is said.
  • Write down questions to ask your doctor.

Questions to ask your doctor

  • What is likely causing my symptoms or condition?
  • What kinds of tests do I need?
  • What course of action do you recommend?
  • What are the alternatives to the approach you're suggesting?
  • I have other health conditions. How can I best manage them together?
  • Are there any restrictions that I need to follow?
  • Are there any brochures or other printed material that I can take home with me? What websites do you recommend?

Don't hesitate to ask other questions during your appointment if you don't understand something or need more information.

What to expect from your doctor

Your doctor is likely to ask you a number of questions, including:

  • When did you begin experiencing symptoms?
  • Have your symptoms been continuous or occasional?
  • How severe are your symptoms?
  • Have you had a fever?
  • What, if anything, seems to improve your symptoms?
  • What, if anything, appears to worsen your symptoms?

To diagnose atelectasis and determine the underlying cause, your doctor may order tests, including:

  • Chest X-ray. A chest X-ray usually can diagnose atelectasis.  Occasionally, a foreign body, a common cause of obstructive atelectasis in children and adults, may be seen on this type of imaging.
  • CT scan. CT is more sensitive than plain X-ray in detecting atelectasis because it can measure lung volumes in all or part of a lung. A CT scan can also help determine whether a tumor may have caused your lung to collapse — something that may not show up on a regular X-ray.
  • Oximetry. This simple test uses a small device placed on one of your fingers to measure the oxygen saturation in your blood.
  • Bronchoscopy. A flexible, lighted tube threaded down your throat enables your doctor to see and possibly remove, at least partially, obstructions in your airway, such as a mucus plug, tumor or foreign body.

Treatment of atelectasis depends on the cause. Atelectasis of a small area of your lung may subside without treatment. If there's an underlying condition, such as a tumor, treatment may involve removal or shrinkage of the tumor with surgery, chemotherapy or radiation.

Chest physiotherapy

Techniques that help people breathe deeply after surgery to re-expand collapsed lung tissue are very important. These techniques are best learned before surgery. They include:

  • Coughing.
  • Clapping (percussion) on your chest over the collapsed area to loosen mucus. You can also use mechanical mucus-clearance devices, such as an air-pulse vibrator vest or a hand-held instrument.
  • Performing deep-breathing exercises (incentive spirometry) and using a device to assist with deep coughing may be helpful.
  • Positioning your body so that your head is lower than your chest (postural drainage). This allows mucus to drain better from the bottom of your lungs.

Supplemental oxygen can help relieve shortness of breath.

Surgical or other procedures

Your doctor may suggest removal of airway obstructions, which may be done by suctioning mucus or by bronchoscopy. Bronchoscopy uses a flexible tube threaded down your throat to clear your airways.

Use of continuous positive pressure may be helpful in some people who are too weak to cough and have low oxygen levels (hypoxemia) after surgery.

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 surgery. If you're scheduled for surgery, talk with your doctor about how to reduce your risk of atelectasis.

June 11, 2015