Answer to Question 1
ANS: A
In the normal upright subject at rest, alveoli at the apexes of the lungs have minimal or no perfu-sion, and thus contribute to the total volume of dead space ventilation.
Answer to Question 2
ANS: C
Physiologic dead space includes both the normal and abnormal components of wasted ventila-tion. VDphy is the preferred clinical measure of ventilation efficiency. Measuring VDphy more accu-rately assesses alveolar ventilation.
