US Patent 7753868 Multi-lumen catheter

A catheter for use in extracorporeal treatment of a bodily fluid includes an elongated tubular member having a pair of lumens extending therein, and a septum separating the lumens. A first lumen comprises a withdrawal lumen, and a second lumen comprises an infusion lumen. A withdrawal port disposed along a length of the tubular member communicates with the withdrawal lumen for receiving fluid from a body vessel for transport to a treatment unit, such as a dialyzer. An infusion port disposed along a length of the tubular member communicates with the infusion lumen for returning treated fluid to the vessel. A passageway is formed in an outer wall of the tubular member adjacent the infusion lumen and extends through the septum. A generally tubular conduit extends through the passageway such that the withdrawal lumen communicates with an environment exterior of the tubular member outer wall.