Atelectasis refers to an area of collapsed or nonexpanded lung. It is reversible, butareas of atelectasis predispose for infection due to decreased mucociliary clearance.
The major types are as follows:
· Obstruction/resorption atelectasis is collapse of lung due to resorption ofair distal to an obstruction; examples include aspiration of a foreign body, chronic obstructive pulmonary disease (COPD), and postoperative atelectasis.
· Compression atelectasis is atelectasis due to fluid, air, blood, or tumor in thepleural space.
· Contraction (scar) atelectasis is due to fibrosis and scarring of the lung.
· Patchy atelectasis is due to a lack of surfactant, as occurs in hyaline membranedisease of newborn or acute (adult) respiratory distress syndrome (ARDS).