Atelectasis is a partial or total collapse of one or both of the lungs. It occurs when tiny air sacs in the lungs known as alveoli deflate. Bibasilar atelectasis is the collapse of the lowest lobes in both lungs.

Bibasilar atelectasis can cause severe complications if left untreated. How doctors deal with it will vary based on what has caused the collapse.

In this article, learn more about the causes and symptoms of bibasilar atelectasis, as well as what to expect during recovery.

What is bibasilar atelectasis?

man coughing and having difficulties breathing which could be caused by bibasilar atelectasis
Symptoms of bibasilar atelectasis may include shortness of breath, wheezing, and coughing.

A person’s lungs are made up of several areas, each of which is called a lobe. The right lung has three lobes, and the left lung has two lobes.

When someone experiences bibasilar atelectasis, the lowermost lobes of their lungs collapse entirely or partially.

The lobes of the lungs are filled with millions of tiny air sacs called alveoli. The alveoli are arranged in clusters and surrounded by blood vessels. When a person breathes in and out, the alveoli allow their blood to collect oxygen and get rid of carbon dioxide.

During bibasilar atelectasis, the alveoli in the base of the lungs deflate and stop performing this essential task. Oxygen may not be able to reach the vital organs, making bibasilar atelectasis life-threatening in some cases.

Bibasilar atelectasis can also leave behind scarring, which could lead to reduced lung function afterward.

The condition is more common after major surgery, but may also be a complication of other issues.

The condition is sometimes confused with pneumothorax. While the two conditions are similar, they have different causes. In some cases, pneumothorax may lead to atelectasis on one side.


If only a small portion of the lung collapses, atelectasis may not cause any symptoms. If a person does experience symptoms, these may include:

  • shortness of breath
  • feeling their breath is too shallow or quick
  • not being able to take a full, satisfying breath
  • coughing
  • wheezing
  • lots of mucus or sputum

Difficulty breathing is the most common symptom. A person may have other symptoms as well, depending on the underlying cause.


Woman lying in a hospital bed
Bibasilar atelectasis is most common after a major surgical procedure.

It is most common for a person to experience bibasilar atelectasis after they have undergone a major surgical procedure, involving general anesthesia.

There is a range of other possible causes, as well. Doctors class these causes as either obstructive or nonobstructive.

Obstructive causes

A person may experience obstructive atelectasis when something blocks their airway and prevents their lung from filling correctly. This can occur for a variety of reasons, including:

  • Foreign object: If someone inhales or improperly swallows a foreign object, it can obstruct their airflow and cause bibasilar atelectasis.
  • Mucus plug: After chest or lung surgery, many people are advised not to cough to avoid stressing the lungs. Not coughing can cause a buildup of mucus in the lungs, which may block the airways. Sometimes, a doctor will suction out this buildup after surgery, but it can continue to accumulate while a person is recovering. Other conditions, including asthma and cystic fibrosis, may also lead to mucus plugs.
  • Tumor: A tumor can narrow or completely block off the airway.
  • Blood clot: Significant bleeding in the lungs may build up and cause a blood clot. A clot can block the airway and cut off the flow of oxygen, collapsing a lobe or lung.
  • Narrowing of the airways: When a person has a severe disease, its progression can lead to narrowing of their airways, eventually causing a collapse. Chronic infections can also cause inflammation and scarring, constricting the main airways.

Nonobstructive causes

Pressure rather than a blockage causes nonobstructive atelectasis.

Things that can put pressure on the lungs and make it hard for them to fill up include:

  • Anesthesia: The use of anesthesia during surgery may cause bibasilar atelectasis. Anesthesia changes a person’s regular breathing pattern. The normal gas exchange in their body may also be affected. This combination could lead to alveoli collapsing.
  • Pleural effusion: Excess fluid can build up in the cavity between the lung and the chest known as the pleural space. This can put too much pressure on the lung, causing it to collapse.
  • Pneumonia: Lung infections, such as pneumonia, may cause a collapse due to inflammation.
  • Scar tissue: Scarring in the lungs can come from surgery, lung diseases, or inhaling harmful chemicals. Scar tissue can permanently damage the lungs and could lead to a lung collapse.
  • Trauma: When a person suffers a chest injury from a traumatic event, such as a car crash, it could make their breathing difficult and compress their lungs.
  • Pneumothorax: Air that leaks into the pleural space can put pressure on the lungs, making it hard for them to inflate. This pressure can lead to a collapse of one or more lobes.
  • Tumor: A tumor that is not near the airway may put pressure on the lung as it grows. This pressure may collapse the lobe or the entire lung.
  • Drugs: Some opioids or sedative drugs may put a person at risk for atelectasis, especially if they use large amounts of these substances.


doctor looking at x ray of the chest
A doctor may order a chest X-ray if atelectasis is suspected.

Atelectasis is often confused with pneumothorax, so a thorough diagnosis is necessary. Doctors may do a physical exam and may also want to monitor a person’s oxygen levels or lung function periodically to note any changes.

If they suspect atelectasis, they will usually order a chest X-ray, ultrasound, or computed tomography (CT) scan to confirm their diagnosis.

A doctor may also perform a bronchoscopy. This procedure is when they insert a tube through a person’s nose or mouth to get a closer look at their airways.


How doctors treat bibasilar atelectasis depends largely on what has caused the collapse.

To treat blockages, they will first try to remove the obstruction, using methods such as suction, drainage, or chest percussion. Some medications may also help break up and expel fluids.

To treat causes related to pressure, doctors will relieve the pressure in the lung and allow it to expand fully. This should restore function in the lungs.

When surgery causes atelectasis, doctors may recommend therapies to allow the lungs to expand naturally. They may tell a person to do deep breathing exercises, walk around after surgery to increase their breathing, and gently cough up mucus if possible.

Lung conditions or medical conditions causing atelectasis will need to be treated completely to help prevent further collapse. For instance, if a person has a tumor, they may require radiation therapy, surgery, or chemotherapy.


Bibasilar atelectasis must be caught early on and treated quickly to give a person the best chance of recovery without any severe complications.

If there is extensive damage to the lungs or the collapse is not treated urgently, possible complications can include:

  • pneumonia
  • hypoxia or when the blood does not carry enough oxygen
  • respiratory failure, which can be life-threatening
  • scar tissue


Many people experience bibasilar atelectasis while they are still in the hospital and recovering from surgery. Already being in the hospital can make diagnosis and treatment easier, and may help prevent complications.

In cases where a person notices symptoms when they are no longer in the hospital, it is crucial for them to visit a doctor urgently for treatment.

By catching the condition early, they may reduce their risk of scarring and other complications in the lungs.

When treated early, many people can recover from bibasilar atelectasis without any long-term side effects.