Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at June 20, 2016

Atelectasis refers to a respiratory complication that usually manifests as a complication of surgery. It involves the partial or complete collapse of a lobe of a lung or the entire lung.


Definition & Facts

Atelectasis develops when the alveoli which are the small air sacs in the lung deflate and collapse. In addition to complications from surgery, atelectasis can also be a complication of various pulmonary issues such as cystic fibrosis, lung tumors, inhaled foreign objects, fluid in the lung, chest injuries, and respiratory weakness.

This condition can affect people of any age. The involved amount of lung tissue can differ, depending on the root cause of the collapse. Atelectasis can be either acute or chronic. In acute situations, the lung collapses quickly. However, in chronic atelectasis, the lung collapses over a period of time due to a variety of causes such as infection and scarring.

Symptoms & Complaints

Atelectasis may go unnoticed with no signs or symptoms. However, it may produce symptoms such as a small cough, chest pain, fast and shallow breathing, low oxygen saturation, cyanosis, pleural effusion, and increased heart rate.

One common misconception of atelectasis is that it causes a high grade fever following surgery. Studies have shown, however, that the incidence of fever is not correlated with atelectasis.


A blocked airway (obstructive atelectasis) or pressure from the outside of the lung (nonobstructive atelectasis) can cause atelectasis. The majority of people who have undergone surgery experience a degree of atelectasis due to anesthesia. While under anesthesia, normal breathing patterns change as do the absorption of pressures and gases. This may all combine to create some collapse of the small air sacs in the lungs.

Obstructive atelectasis can be caused by several mechanisms. An accumulation of mucus in the airways, creating a mucus plug, is a common cause. This usually happens during surgery because the patient is unable to cough. Drugs that are given to patients during surgery prevent the lungs from inflating completely, so normal respiratory secretions are able to collect in the airway without having a way to get out.

While using a suction in the lungs during surgery may help to clear away mucus, it may continue to build up following surgery. Pulmonary mucus plugs are also common among children, people suffering from cystic fibrosis, and people having a severe asthma attack.

Obstructive atelectasis can also be caused by the inhalation of an object such as a small toy part or a peanut. This is most common in children. Secondary diseases that cause narrowing of major airways can also result in atelectasis. This includes fungal infections, tuberculosis, as well as diseases that can scar the airways. A blood clot or tumor or other obstructive growth located in an airway can also cause it to narrow.

Some causes of nonobstructive atelectasis are injury resulting in chest trauma, such as a fall or a car accident, which prevent the patient from taking in deep breaths. The buildup of fluid in the lung's tissues can also be a cause, as well as pneumonia, which can cause temporary atelectasis.

Pneumothorax, which is air leaking into the area between the chest wall and the lungs can indirectly cause atelectasis. The scarring of any lung tissue, which may be caused by injury, surgery, or lung disease can result in atelectasis.

Diagnosis & Tests

Tests will be done to diagnose atelectasis as well as determine its cause. These diagnostic tests include chest X-rays, which can typically diagnose atelectasis. This may not be effective in diagnosing obstructive atelectasis, due to foreign objects not showing up on X-rays, whereas a CT scan provides a more complete picture of the lungs and can detect atelectasis due to its ability to measure lung volumes. This test can also help to see if there is a tumor causing a lung collapse, which may not show up on an X-ray.

A pulse oximetry can also be performed, which is a simple test that uses devices placed on the fingers in order to measure the oxygen saturation in the blood. A bronchoscopy is a more invasive procedure in which a tube is inserted down the throat so a doctor can determine what is obstructing the airways, and it can also be used to treat and remove such obstructions.

Treatment & Therapy

Depending on the cause, treatment of atelectasis can vary. Atelectasis in a small area of the lung may heal without treatment. However, if an underlying condition is present, treatment could involve surgery for the shrinkage or removal of the tumor.

Chest physiotherapy may also be used to help people breathe more deeply following surgery in order to re-expand the small sacs in the lungs. This usually involves a therapist or caregiver patting or clapping the chest firmly while the patient coughs in order to help the mucus to loosen. Postural drainage is another component of chest physiotherapy that involves positioning the head lower than the chest to help mucus rise and drain.

Surgery may be suggested to remove airway obstructions. This can be done with a bronchoscopy which suctions out obstructions. This may be especially helpful for those who cannot cough by themselves due to weakness. 

Prevention & Prophylaxis

The best way to prevent atelectasis in children is to keep them away from small objects that they may accidentally inhale as this is the most common cause in children. For adults, refraining from smoking prior to surgery can greatly lower the risk of atelectasis. Those who smoke should consider quitting prior to surgery.

After surgery, in order to prevent atelectasis, deep breathing exercises are important with the use of an incentive spirometer. This measures the amount of air that is taken in as well as how fast it is flowing. This encourages slow and deep breathing. Deep breathing and coughing is the most important tool for preventing atelectasis.

Changing positions often after surgery will help mucus to not settle in the lungs. Doctors may also be able to help prevent atelectasis by using a positive-end expiratory pressure tool that uses air pressure to keep the airways clear and the small sir sacs in the lungs open.