Either A or B A. Clinical Criteria: Moderate to severe respiratory distress as evidenced by tachypnea, use of accessory muscles for breathing, or abdominal paradox. B. Blood Gas and Physiologic Criteria: Gas exchange abnormalities including PaCO2>45 with a pH<7.35, or a PaO2/FiO2 ratio<200. [clinicaltrials_resource:52e6bf7745ef97ed4dd8f285b902ac61]

Either A or B A. Clinical Criteria: Moderate to severe respiratory distress as evidenced by tachypnea, use of accessory muscles for breathing, or abdominal paradox. B. Blood Gas and Physiologic Criteria: Gas exchange abnormalities including PaCO2>45 with a pH<7.35, or a PaO2/FiO2 ratio<200. [clinicaltrials_resource:52e6bf7745ef97ed4dd8f285b902ac61]