This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Value of Pa02/ Fi02 chracteristic of ARDS is 
Select and explain. 
A. < 200 mmHg, B. 200 - 400 mmHg, C. 400 - 600 mmHg, D. 600 - 800 mmHg
A: < 200 mmHg
Answer: A: < 200 mmHg 
Explanation: Answer- A. < 200 mmHgAcute respiratory distress syndrome (ARDS) is a clinical symdrome of severe dyspnea of rapid onset, hypoxemia, and diffirse pulmonary infiltrates leading to respiratory failure.The aerial PaO, (in mmHg)/FiO, (inspiratory O, fraction) <200 mmHg is characteristic of ARDS, while a PaO, /FiO, between 200 and 300 identifies patients with ALI who are likely to benefit from aggressive therapy.