Answer to Question 1
ANS: B
Compensation for pleural leaks sometimes can be accomplished by increasing volume delivery to the patient. The amount of air leaking through the pleural drainage system can be determined by comparing the inspiratory and expiratory VT.
Answer to Question 2
ANS: C
Asynchronous breathing may be seen in patients with COPD when PSV is used. COPD patients often show active short inspirations and active long expirations. If the patient begins to exhale actively during the inspiratory phase of PSV, the flow may not drop to the necessary cycling value to end inspiration on the pressure-supported breath, resulting in a sudden rise in the scalar at the end of the breath. This problem can be prevented in these patients by using a ventilator with adjustable flow-cycling characteristics.