A method for maintaining clear passageways in an extracorporeal blood flow
system. The method comprises intermittently providing one or more
anti-clotting agents to a passageway of the extracorporeal blood flow
system. Also disclosed is an extracorporeal blood flow system. The system
comprises a passageway, and a device operatively connected to provide one
or more anti-clotting agents to a least a portion of said passageway.