Which factor does NOT contribute to atelectasis?

• A. Inadequate ventilation
• B. Surfactant deficiency
• C. Airway obstruction
• D. Adequate coughing and deep breathing

Answer: (D)

Atelectasis occurs when alveoli collapse because they aren’t kept open by enough air or surfactant. Inadequate ventilation means air doesn’t reach the alveoli, so they deflate. Surfactant deficiency raises surface tension, making alveoli easier to collapse. Airway obstruction blocks air flow to distal airways, leading to gas absorption and collapse of the affected alveoli. Adequate coughing and deep breathing, by contrast, helps reopen and maintain inflated alveoli, preventing atelectasis. So this factor does not contribute to atelectasis.