A patient with a normal PaO2 and cardiac output is exhibiting ...

[captainjonesify]

A patient with a normal PaO2 and cardiac output is exhibiting signs and symptoms of tissue hy-poxia. What is the most likely cause?
 
  a. Hemoglobin deficiency
  b. Low ambient PO2
  c. Right-to-left shunt
  d. Hypoventilation

Question 2

The expected PaO2 for an 80-year-old man who is otherwise in good health and breathing room air is approximately what level?
 
  a. 50 mm Hg
  b. 75 mm Hg
  c. 80 mm Hg
  d. 90 mm Hg

[kxciann]

Answer to Question 1

ANS: A
If the blood hemoglobin is loweven when the PaO2 is normalhypoxia can occur because of low O2 content in the arterial blood.

Answer to Question 2

ANS: B
One may estimate the expected PaO2 in older adults by using the following formula:
Expected PaO2 = 100.1  (0.323  age in years)