Question

A diagnosis of respiratory failure can be made if which of the following are present?

1. PaO₂ 55 mm Hg, FIO₂ 0.21, PB 760 mm Hg
2. PaCO₂ 57 mm Hg, FIO₂ 0.21, PB 760 mm Hg
3. P(A-a)O₂ 45 mm Hg, FIO2 1.0, PB 760 mm Hg
4. PaO₂/FIO₂ 400, PB 750 mm Hg
a. 1 and 2
b. 1, 3, and 4
c. 3 and 4
d. 1, 2, 3, and 4

Answer 1

A diagnosis of respiratory failure can be made if a PaO₂ of 55 mm Hg, PaCO₂ of 57 mm Hg, P(A-a)O₂ of 45 mm Hg, and PaO₂/FIO₂ ratio of 400 are present.

Step-by-step explanation:

A diagnosis of respiratory failure can be made if which of the following are present?

1. PaO₂ 55 mm Hg, FIO₂ 0.21, PB 760 mm Hg
2. PaCO₂ 57 mm Hg, FIO₂ 0.21, PB 760 mm Hg
3. P(A-a)O₂ 45 mm Hg, FIO₂ 1.0, PB 760 mm Hg
4. PaO₂/FIO₂ 400, PB 750 mm Hg

The correct answer is d. 1, 2, 3, and 4. A diagnosis of respiratory failure can be made if all the listed parameters are present. Proper gas exchange in the lungs requires the PaO₂ to be at least 60 mm Hg and the PaCO₂ to be below 45 mm Hg. Any values outside of these ranges indicate respiratory failure.