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

Question

Quizplus · Accepted Answer

Respiratory failure is defined as a paO2 less than 60 mm Hg and/or a paCO2 greater than 50 mm Hg. Option 1 has a paO2 of 55 mm Hg, which is below the normal range and indicates respiratory failure. Option 2 has a paO2 of 57 mm Hg, which is close to the borderline range but not indicative of respiratory failure. Option 3 has a paO2 of 45 mm Hg, which is well below the normal range and indicates respiratory failure. Option 4 provides a ratio of paO2/FiO2, which can be used to assess the severity of respiratory failure, but does not indicate whether respiratory failure is present or not. Therefore, options 1 and 2 are the only ones that provide information about the presence of respiratory failure.

A Diagnosis of Respiratory Failure Can Be Made If Which