Causes and Treatment of Atelectasis

Surgery is a common cause for this type of lung collapse

Illustration by Joshua Seong. © Verywell, 2018. 

Atelectasis is a medical term used to describe the complete or partial collapse of a lung. It is sometimes referred to as a "collapsed lung," although the term can also be applied to a condition called pneumothorax.

When atelectasis occurs, fresh air is unable to reach the tiny structures of lungs, called the alveoli, where oxygen and carbon dioxide are exchanged. This results in decreased levels of oxygen being delivered to the organs and tissues of the body (hypoxia).

Atelectasis may be acute, occurring suddenly over the matter of minutes, or chronic, developing over a period of days to weeks.

Causes of Atelectasis

There are four primary causes of atelectasis: hypoventilation, airway obstruction, airway compression, and adhesions.

  • Hypoventilation (breathing at an abnormally slow rate) is common during surgery, especially with general anesthesia, or when a person is placed on a respirator. The very act of shallow breathing prevents air from getting to the alveoli, causing the air sacs to deflate and collapse. Hypoventilation is the most common cause of atelectasis, especially after chest surgery.
  • Airway obstruction may be caused when something blocks a passage either inside the lung (like mucus or a foreign object) or outside of the lungs (like a tumor which presses on the airway and causes obstruction). Bronchioloalveolar carcinoma is one type of cancer known to cause tumors in the alveoli and allied passages.
  • Airway compression is often caused by the buildup of fluid in the space surrounding the lungs (pleural effusion). It may also be the result of an enlarged heart, an aneurysm, a tumor, enlarged lymph nodes, or accumulation of fluids in the abdominal cavity (ascites).
  • Adhesions are an abnormal condition where tissues begin to stick together. Normally, internal tissues and organs have slippery surfaces, so they can shift easily as the body moves. The lubricating substance is called surfactant. When surfactant is lacking, the lungs lose surface tension and can collapse.

    Other factors contributing to atelectasis include obesity, smoking, prolonged bed rest/immobility, rib fractures (which can result in shallower breathing), narcotics or sedatives (which can slow respiration), and respiratory distress syndrome (RDS) in newborns.

    Symptoms of Atelectasis

    Atelectasis often has few symptoms if it develops slowly or involves only a small portion of the lung. Conversely, if the condition develops rapidly or affects a larger portion, symptoms may be dramatic and even lead to shock. Atelectasis typically occurs bilaterally, meaning in either one lung or the other.

    Common symptoms include:

    • Shortness of breath (dyspnea)
    • A hacking, nonproductive cough
    • A sharp chest pain that worsens with a deep breath (pleuritic chest pain)
    • A bluish tinge to the lips, toes, or fingers caused by a lack of oxygen (cyanosis)

    Diagnosis of Atelectasis

    If your doctor suspects you have atelectasis, he or she will perform a physical exam by tapping on (percussing) the chest to listen for tell-tale sounds. If there is a partial or complete lung collapse, breathing sounds will be quiet or noticeably absent.

    Following this, the doctor will order a number of investigations which may include:

    Treatment Options for Atelectasis

    Treatment of atelectasis depends on the underlying cause, with the aim of re-expanding the lung to its normal size. The approaches can vary. If a tumor is the cause of the collapse, surgery may be involved.

    For pleural effusion, drainage of the pleural cavity may be required. For internal obstructions, bronchoscopy may be used to remove a foreign object, while bronchodilation medications may assist with the opening of airway passages. In most cases, a combination of therapeutic approaches will be needed.

    When symptoms are pronounced, positive end-expiratory pressure (PEEP) may be used. This is a treatment in which a mixture of oxygen is given by mask under pressure, preventing the lungs from collapsing completely during exhalation. If symptoms are severe, intubation and ventilation may be needed until the underlying condition is fully under control.

    When atelectasis is chronic, it can be often difficult to get the lungs to re-expand. Removal of the damaged portion of the lung (via a lobectomy or segmental resection) may be indicated.

    Complications may result when bacteria become trapped in the area of the collapse. This can lead to the development of an infection, including pneumonia and sepsis. Bronchiectasis, an abnormal widening of the airways which results in a pooling of fluid the lungs, can also sometimes occur. When a large portion of the lungs is affected by these things, respiratory failure may result.

    Preventing Atelectasis After Surgery

    Chest surgery remains the predominant cause of atelectasis. To prevent it from occurring after a surgical procedure, doctors will typically advise you to stop smoking first and foremost.

    After surgery, there are three things you should do ensure your lungs remain fully inflated:

    1. Perform deep breathing exercises, focusing on long inhales and controlled exhales. Pain medication may also be prescribed if breathing is especially uncomfortable.
    2. Make an effort to cough to clear any mucus or sputum from the lungs.
    3. Change your position, sitting up or moving around as much as your doctor allows.
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