A Diagnosis of Respiratory Failure Can Be Made If Which

Multiple Choice

A diagnosis of respiratory failure can be made if which of the following are present?
1) PaO₂ 55 mm Hg, FiO₂ 0.21, P_B 760 mm Hg
2) PaCO₂ 57 mm Hg, FiO₂ 0.21, P_B 760 mm Hg
3) P(A-a) O₂ 45 mm Hg, FiO₂ 1.0, P_B 760 mm Hg
4) PaO₂/FiO₂ 400, P_B 750 mm Hg

A) 1 and 2 only
B) 1, 3, and 4 only
C) 3 and 4 only
D) 2, 3, and 4 only