Which of the following is the typical ratio of sweep flow to pump flow?

a. 1:1
b. 3:1
c. 6:1
d. 9:1

ANS: A
The ratio of sweep flow to pump flow is often 1:1. When using 4 L/min pump flow, typically the sweep flow would be initiated at 4 L/min. The oxygenator functions to provide gas exchange much like native lungs perform gas exchange—O2 diffuses into the blood from a gas source with a higher partial pressure and carbon dioxide diffuses out of the blood into a gas source with a lower partial pressure.