Author Question: Compared to a normal individual, when a patient with a severe obstructive impairment such as ... (Read 53 times)

colton · **on:** Jul 16, 2018

Compared to a normal individual, when a patient with a severe obstructive impairment such as emphysema increases ventilation, which of the following occurs?

a. Carbon dioxide production falls as anaer-obic metabolism increases.
b. Oxygen consumption increases at a faster rate than normal.
c. Oxygen consumption rises faster than carbon dioxide production.
d. The anaerobic threshold is reached later than normal.

Question 2

Which of the following factors would tend to increase the frictional component of the work of breathing?

1. Decreased compliance of the lungs or thorax
2. High frequencies of breathing
3. Increased Raw
a. 1 and 2 only
b. 1, 2, and 3
c. 1 and 3 only
d. 2 and 3 only

aadams68 · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: B
In the presence of pulmonary disease (either obstructive or restrictive), the oxygen cost of breathing may increase dramatically with increasing ventilation (Figure 11-13). In an obstructive disease such as emphysema, increased ventilation causes the oxygen consumption of the respira-tory muscles to increase rapidly.

Answer to Question 2

ANS: D
In healthy individuals, the mechanical work of breathing depends on the pattern of ventilation. High breathing rates (and hence, high flows) increase frictional work. Patients who have airway obstruction (i.e., increased Raw) also experience increased frictional work of breathing.