Atelectasis is a complete or partial collapse of the entire lung or an area of the lung. It occurs when the tiny air sacs (alveoli) within the lung become filled with alveolar fluid or deflated.

It is one of the most common breathing complications after surgery, it can make breathing difficult, especially if you have lung disease.

There may not be any obvious signs of atelectasis, but symptoms can include breathing difficulties, rapid, shallow breathing, wheezing and a persistent cough.

Atelectasis can be caused by a blocked airway (obstructive) or pressure from outside the lung (nonobstructive). General anesthesia is a common cause of atelestasis as it changes the regular breathing pattern affects the exchange of lung gases which cause the alveoli to deflate.

Obstructive atelectasis can be caused by a foreign body or a tumor inside the airway. Nonobstructive atelectasis can be caused by an injury, pleural effusion, pneumonia, pneumothorax, scarring of the lung tissue or a tumor.

You may experience low blood oxygen, pneumonia or respiratory failure as a result of atelectasis.

Treatment will depend on the cause of atelectasis; some mild cases will go away without treatment. If the complication is the result of a blockage, surgery will be required to remove the blockage.

There are some techniques that will help you breathe deeply after surgery, these can include deep-breathing exercises, tapping the chest area to loosen mucus and positioning your body so that your head is lower than your chest. In some cases, a breathing tube will be helpful.