A patient breathing room air at sea level has the following arterial blood gases: PaO₂ = 62 mm Hg; PCO₂ = 75 mm Hg. When the FIO₂ is raised to 0.28, the PaO₂ rises to 95 mm Hg. What is the most likely cause of the hypoxemia?

Question

Quizplus · Accepted Answer

In the case of simple hypoventilation, a rise in the alveolar PCO₂ is always accompanied by a proportionate fall in alveolar PO₂. The P(A-a)O₂ is normal in such cases. The hypoxemia will respond readily to O₂ therapy.

A Patient Breathing Room Air at Sea Level Has the Following