Patent ID: 7438699

Claim:
A system for priming a blood-flow circuit coupled with a pump, comprising: a pump tube assembly comprising a pump tube and a pump tube connector, the connector comprising a housing with a lumen therethrough having a housing cross-sectional area, the housing also comprising a first port, a membrane extending across the first port, a second port configured to couple with the pump tube, and a third port configured to couple with a source of biocompatible liquid; and a cannula assembly comprising: a cannula comprising a first end and a second end configured to couple with a blood vessel, the cannula defining a portion of a cannula lumen having a first cross-sectional area; and a cannula connector comprising a piercing member that defines a portion of the cannula lumen having a second cross-sectional area, the second cross-sectional area being substantially the same as the first cross-sectional area, the piercing member configured to pierce the membrane upon joining the cannula connector to the pump tube connector; and wherein the piercing member comprises a first surface and the pump tube connector comprises a second surface, the first and second surfaces configured to engage so as to provide a seamless lumen within the pump tube connector at least at the location where the first and second surfaces engage; and wherein the second surface is formed of a material that conforms to the first surface when the piercing member is fully inserted, whereby a seal is formed between the first and second surfaces.