What can you assume about a patient who has a mismatch and ...

[codyclark]

What can you assume about a patient who has a mismatch and exhibits hypercapnia?
 
  a. The central nervous system is not re-sponding to the increased PCO2.
  b. The patient cannot sustain the high E to overcome the high VD.
  c. The patient is compensating for an acute metabolic alkalosis.
  d. The patient is compensating for a chronic metabolic acidosis.

Question 2

A patient breathing 40 O2 at sea level has a PaO2 of 50 mm Hg, a PCO2 of 30 mm Hg, and a PAO2  PaO2 of 250 mm Hg. When the FiO2 is raised to 0.7, the PaO2 rises to only 58 mm Hg. Hypoxemia is primarily due to which of the following?
 
  a. Hypoventilation
  b. Impaired diffusion
  c. Right-to-left shunt
  d. imbalance

[Shshxj]

Answer to Question 1

ANS: B
An increase in dead space ventilation is caused by either (1) rapid, shallow breathing (an increase in anatomical dead space per minute) or (2) increased physiologic dead space (/ = 0). In either case, the proportion of wasted ventilation increases. Without compensation, this lowers alveolar ventilation per minute and impairs carbon dioxide removal.

Answer to Question 2

ANS: C
A of 0 represents a special type of imbalance. When the is 0, there is blood flow but no ven-tilation. The result is equivalent to a right-to-left anatomical shunt, shown at the bottom of Figure 12-15. Venous blood bypasses ventilated alveoli and mixes with freshly oxygenated arterial blood, resulting in what is called a venous admixture. Right-to-left physiologic shunting results in a more severe form of hypoxemia than does a simple .

[codyclark]

Excellent

[bitingbit]

TYSM