Method and apparatus for using dual-lumen catheters for extracorporeal treatment

A method of extracorporeal hemodialysis, hemofiltration, plasmapheresis, and cytopheresis treatments of the human blood, requiring continuous blood flow at high flow rates in both directions between the patient and the extracorporeal treatment equipment, in which a dual-lumen catheter is inserted into a venous segment so that blood can be withdrawn through one lumen of the catheter and returned through the other lumen, said method comprising

• inserting said dual-lumen catheter into said venous segment in the direction of the venous blood flow, with a single puncture of said venous segment,
• occluding said venous system so that said segment is engorged on one side of the occlusion and partially collapsed on the other side of the occlusion, said occlusion being positioned so that the entrance to the intake lumen is located in the engorged portion of the venous segment so that said entrance is located in a venous pool of blood sufficient to permit blood to be withdrawn ar relatively high flow rates, and the exit from the return lumen is located in the partially collapsed portion of the venous segment,
• applying a suction to the withdrawal lumen to remove blood from said venous pool at a relatively high rate, and
• treating the withdrawn blood in extracorporeal treatment equipment, and returning blood to the non-engorged portion of said venous segment through the return lument under pressure produced by the extracorporeal treatment equipment.

A method of extracorporeal hemodialysis, hemofiltration, plasmapheresis, and cytopheresis treatments of the human blood, requiring continuous blood flow at high flow rates in both directions between the patient and the extracorporeal treatment equipment, in which a catheter having first and second lumens and respective first and second lumen openings axially displaced from each other is inserted into a venous segment so that blood can be withdrawn through an intake lumen of the catheter and returned through a return lumen in the same catheter, said method comprising the steps of

• inserting said catheter into said venous segment,
• occluding the peripheral venous system at a location between said respective first and second lumen openings so that the veins become engorged on the intake side of the occlusion, containing a venous pool of blood which is continuously fed to said intake lumen via the intercommunications among the veins and continuously replenished via the unoccluded arterial blood flow
• applying a suction produced by the extracorporeal treatment equipment to the withdrawal lumen to remove blood from said venous pool at a relatively high rate, and treating the withdrawn blood in extracorporeal treatment equipment, and
• returning blood to the non-engorged portion of said venous segment through the return lumen under pressure produced by the extracorporeal treatment equipment.