Which of the following occur in pressure-limited modes of ventilation?

1. The volume delivered at a given pressure must decrease as compliance falls.
2. The inspiratory flow varies with patient effort and lung mechanics.
3. Active effort by the patient against inspiration will decrease delivered volume.
4. The volume delivered at a given pressure must increase as Raw rises.
a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: B
An increase in resistance, active exhalation, or muscle tensing by the patient during inspiration also decreases delivered volume in pressure ventilation.