<prompt> What will the estimated Pa02 after giving Fi02 at 0.5 in a normal person?50 mmHg100 mmHg150 mmHg200 mmHg  <response>: Answer- D. 200 mmHgln normal person, the measured PA O2 should equal to 5 x FiO2 . For example, a patient breathing 40 O FiO2 of 0.4 should have a PaO2 5 x 40 200 mmHg. A PA O2 less than 4 to 5 times the FiO2 suggest poor lung function or hypoventilation. 