This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Anatomy
Feature of shock lung is 
Select and explain. 
A. Diffuse alveolar damage, B. Usual interstitial infiltrates, C. Organizing pneumonia, D. Bronchiolitis
A: Diffuse alveolar damage
Answer: A: Diffuse alveolar damage 
Explanation: In ARDS, the presence of alveolar and interstitial fluid and the loss of surfactant can lead to a marked reduction of lung compliance. Without an increase in end-expiratory pressure, significant alveolar collapse can occur at end-expiration,with consequent impairment of oxygenation. Ref Davidson edition23rd pg 199