Which of the following in ARDS is true?

ARDS is a clinical syndrome of severe dyspnoea of rapid onset,hypoxaemia and diffuse pulmonary infiltrates leading to respiratory failure.ARDS is characterised by Po2/Fio2(inspiratory O2 fraction)<200 mmHg.There will be no hypercapnia,so the patient will have type 1 respiratory failure.There will be stiff-lung syndrome with collapse and decreased compliance of the lungs due to loss of surfactant. Reference:Harrison's Medicine-20 th edition,page no:2032.Textbook of pathology-Harsh Mohan,6th edition,page no:463.