What is the pathophysiology of obstructive atelectasis?

Updated: Oct 22, 2020
  • Author: Tarun Madappa, MD, MPH; Chief Editor: Nader Kamangar, MD, FACP, FCCP, FCCM  more...
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Following obstruction of a bronchus, the blood circulating in the alveolar-capillary membrane absorbs the gas from alveoli. This process can lead to retraction of the lung and an airless state within those alveoli in a few hours. In the early stages, blood then perfuses the unventilated lung. This results in a shunt and, potentially, arterial hypoxemia. Subsequent to obstruction of a bronchus, filling of the alveolar spaces with secretions and cells may occur, thereby preventing complete collapse of the atelectatic lung. The uninvolved surrounding lung tissue distends, displacing the surrounding structures. The heart and mediastinum shift toward the atelectatic area, the diaphragm is elevated, and the chest wall flattens.

If the obstruction to the bronchus is removed, any complicating postobstructive infection subsides and the lung returns to its normal state. If the obstruction is persistent and infection continues to be present, fibrosis and/or bronchiectasis may develop.

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