This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
True about ARDS is all except 
Select and explain. 
A. Acute onset, B. PaO2 /FiO2<200mmHG, C. Pulmonary aery wedge Pressure >18mmHg, D. Treatment of choice is mechanical ventilation
C: Pulmonary aery wedge Pressure >18mmHg
Answer: C: Pulmonary aery wedge Pressure >18mmHg 
Explanation: A less severe form is called acute lung injury (ALI).A PaO2/FiO2ra of less than 300 mm Hg with bilateral infiltrates indicates acute lung injury (ALI). ARDS is characterized by:Acute onsetBilateral infiltrates on chest radiograph sparing costophrenic anglesPulmonary aery wedge pressure< 18 mmHg (obtained by pulmonary aery catheterization if PaO2:FiO2< 200 mmHg (26.7 kPa) To summarize and simplify, ARDS is an acute (rapid onset) syndrome that affects thelungs widely and results in a severe oxygenation defect, but is not due to hea failure.