A patient breathing room air at sea level has the following ...

[arivle123]

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?
 
  a. Hypoventilation
  b. Impaired diffusion
  c. Right-to-left shunt
  d. V/Q imbalance

Question 2

An abnormal metabolic state in which the tissues are unable to utilize the O2 made available to them best describes which of the following?
 
  a. Diffusion hypoxia
  b. Dysoxia
  c. Hemic hypoxia
  d. Physiologic shunt

[kilada]

Answer to Question 1

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

Answer to Question 2

ANS: B
Abnormal cellular function prevents proper uptake of O2 is called dysoxia.