Atelectasis is a condition in which the tiny air sacs, known as alveoli, in the lungs are unable to inflate properly, leading to a lack of oxygen supply to the body’s organs, tissues, and blood. Atelectasis may involve complete or partial collapse of the affected lung tissue. Atelectasis is a common respiratory complication that can occur after surgery performed under anesthesia, as well as being a possible consequence of other respiratory problems. These include respiratory weakness, chest injuries, fluid accumulation in the lungs, lung tumors, and cystic fibrosis. Furthermore, inhaling a foreign object can also lead to the development of atelectasis.

Breathing difficulty can be experienced due to atelectasis, especially when an individual already has a lung condition. The appropriate treatment approach will vary depending on the severity and underlying cause of the collapsed lung.

The types of atelectasis are:

  • Compressive atelectasis: When something around the lung, such as fluid, air, blood, or a tumor, pushes against it and causes collapse.
  • Resorptive/obstructive atelectasis: Resorptive atelectasis occurs when the air sacs in the lungs, known as alveoli, collapse due to a lack of air. This can happen when oxygen and carbon dioxide in the alveoli move out of the lungs and into the bloodstream, without being replaced by fresh air. A common cause of resorptive atelectasis is undergoing surgery that requires anesthesia.

Resorptive atelectasis may occur when there is an obstruction inside the lung preventing air from entering the alveoli. This type of atelectasis may result from blockages such as mucus, a tumor, or an object that was unintentionally inhaled.

  • Contraction atelectasis: The condition of lung scarring, or fibrosis leads to a type of lung collapse called contraction atelectasis, where the alveoli are unable to expand properly due to the scarring.
  • Other types of atelectasis: Patchy atelectasis is a type of atelectasis that can occur in newborns, especially premature newborns, as well as in individuals with acute respiratory distress syndrome (ARDS). This type of atelectasis is characterized by insufficient levels of surfactant, a protein that helps prevent the collapse of the lungs.

The collapse of the lungs can be described using different types of atelectasis, such as bibasilar atelectasis, rounded atelectasis, gravity-dependent atelectasis, and subsegmental atelectasis. These terms are used to specify the location, appearance, or extent of the lung collapse.


Atelectasis may not always produce noticeable symptoms, but if it affects significant portions of the lungs, it can result in a reduction of oxygen levels in the bloodstream (known as hypoxemia). The presence of symptoms may depend on the underlying cause of atelectasis, such as chronic obstructive pulmonary disease (COPD) or other conditions. Symptoms caused by this include:

  • Shortness of breath or difficulty in breathing
  • Rapid, shallow breathing
  • Chest pain
  • Wheezing
  • Coughing
  • Bluish discoloration of lips and skins.

It is important to promptly seek medical attention if you experience difficulty breathing, as there may be other conditions besides atelectasis that can cause such symptoms. It is crucial to receive an accurate diagnosis and prompt treatment for any condition that may be affecting your breathing. In case your breathing difficulties worsen, it is necessary to seek emergency medical assistance immediately.


Atelectasis can happen when the airway is blocked or when there is pressure on the outside of the lung. General anesthesia is a known factor that can cause atelectasis. The changes in breathing patterns caused by anesthesia can affect the exchange of gases in the lungs, leading to deflation of the air sacs known as alveoli. It is common for individuals who undergo major surgery to experience some degree of atelectasis, particularly after heart bypass surgery.

The following are two causes of atelectasis.

  • Obstructive atelectasis: Closed airway.
    • Mucus plug: A mucus plug is a collection of mucus in the airways. Due to the inability to cough, it frequently happens both during and after surgery. Surgery-related medications cause patients to breathe less deeply, which causes normal secretions to build up in the airways. During surgery, suctioning the lungs helps clear them, but occasionally they still build up. Children, those who have cystic fibrosis, and adults who experience severe asthma attacks all frequently develop mucus plugs.
    • Inhaled foreign objects: Inhaling a foreign object, such as a peanut or a small toy part, can cause atelectasis, which is a common condition in children.
    • Tumor at the airway: The airway could get smaller due to an abnormal growth.
  • Non-obstructive atelectasis: pressure from outside the lungs.
    • Chest trauma: If a person experiences a trauma to their chest, such as falling or being in a car accident, they may avoid taking deep breaths due to the pain. This can lead to compression of their lungs.
    • Pleural effusion: The pleura is the tissues that line the lungs, and the inside of the chest wall are affected by the buildup of fluid in this condition.
    • Pneumonia: A lung infection called pneumonia of various forms can lead to atelectasis.
    • Pneumothorax: Lung collapse is brought on by air entering the gap between the lungs and the chest wall.
    • Scarring of lung tissue: Scarring may result from surgery, lung illness, or an injury.
    • Tumor: Instead of obstructing the airways, a big tumor may press up against and deflate the lung.

Risk factors

Atelectasis is more likely to occur in those who have the following conditions:

  • Age: Older people are more susceptible to develop this condition.
  • Injury: An extremely painful chest injury or rib fracture. The inability to breathe deeply could result from this.
  • Surgery: Surgery on your chest or abdomen may involve the use of medication to induce relaxation or unconsciousness (anesthesia), which may impede your ability to take deep breaths. This can lead to lung atelectasis.
  • Medications: Some medications may cause the patient to experience shallow breathing.
  • Lung disease: such as asthma, COPD, bronchiectasis or cystic fibrosis
  • Smoking: Smoking or had exposure to smoke.