Atelectasis is defined as an area of collapsed or non-expanded lung. There are four major types of atelectasis: (1) obstruction/resorption atelectasis caused by obstruction distal to the lung, such as from aspiration or COPD; (2) compression atelectasis caused by fluid, air, blood or tumor in the pleural space; (3) contraction (scar) atelectasis caused by fibrosis and scarring of the lung; and (4) patchy atelectasis caused by a lack of surfactant as seen in neonates and ARDS patients. Atelectasis causes decreased oxygenation and an increased risk of infection, though most cases are reversible disorders.

1. AtelectasisAtelectasis
Definition:Definition:
Area of collapsed or non expanded lung.Area of collapsed or non expanded lung.
It refers either to incomplete expansion of the lungs or to the collapse ofIt refers either to incomplete expansion of the lungs or to the collapse of
previously inflated lung substance , producing area of relativelypreviously inflated lung substance , producing area of relatively
airless pulmonary parenchyma.airless pulmonary parenchyma.

2. Major typesMajor types
a. Obstruction/resorption atelectasisa. Obstruction/resorption atelectasis
 Collapse of lung due to resorption of air distal to an obstruction.Collapse of lung due to resorption of air distal to an obstruction.
Examples:Examples:
 aspiration of a foreign bodyaspiration of a foreign body
 chronic obstructive pulmonary disease (COPD),chronic obstructive pulmonary disease (COPD),
 or postoperativeor postoperative

3. b. Compression atelectasisb. Compression atelectasis - due to fluid, air, blood, or tumor in the- due to fluid, air, blood, or tumor in the
pleural spacepleural space
c. Contraction (scar) atelectasisc. Contraction (scar) atelectasis - due to fibrosis and scarring of- due to fibrosis and scarring of
the lungthe lung
d. Patchy atelectasisd. Patchy atelectasis - Due to a lack of surfactant in neonatal &- Due to a lack of surfactant in neonatal &
acute (adult) respiratory distress syndrome(ARDS)acute (adult) respiratory distress syndrome(ARDS)
 Altelectasis causes decrease oxygenation and predisposed to infectionAltelectasis causes decrease oxygenation and predisposed to infection
 Most of the atelectasis are reversible disorder.Most of the atelectasis are reversible disorder.

5. Define Atelectasis. Write down the typesDefine Atelectasis. Write down the types
of Atelectasisof Atelectasis

6. Define Atelectasis. Write down the typesDefine Atelectasis. Write down the types
of Atelectasisof Atelectasis