Apparatus for blood dialysis and filtration

A hemodiafiltration apparatus capable of extracorporeal circulation operation in which extraction and reinfusion of blood are performed by using a single needle, comprising:

• a blood supply system for supplying blood;
• a dialysis fluid supply system for supplying a dialysis fluid;
• a control system for controlling movement of a fluid between the two supply systems, a blood circulation system having an arterial side blood circuit for extracting blood from a patient and flowing it into a hemodialyzer and a venous side blood circuit for returning blood from the hemodialyer to the patient, at least one of the arterial side blood circuit and the venous side blood circuit of the blood circulation system having a blood pump which can control a flow rate and can operate in normal and opposite directions, the dialysis fluid supply system having a dialysis fluid supply line for perfusing the hemodialyzer with a dialysis fluid and a dialysis fluid discharge line, at least one of the two blood circuits of the blood circulation system having a blood pump which can control the flow rate and can urn operate in normal and opposite directions, the dialysis fluid supply line and the dialysis fluid discharge line having a supply delivery means for supplying a dialysis fluid and a discharge delivery means for discharging the dialysis fluid, respectively, one of the dialysis fluid supply line and the dialysis fluid discharge line having at least one filtration back-filtration fluid supply means for carrying out filtration and back-filtration together with the delivery means, which can operate in normal and opposite directions and can control a flow rate, and at least one water removing and fluid discharge means, and having a mechanism for extracting blood into the blood circuit by flowing out a fluid in the blood circuit to a dialysis fluid circuit side by filtration through the hemodialyzer accommodating a hollow yarn membrane and a mechanism for returning the blood in the blood circuit to the patient by flowing the dialysis fluid from the dialysis fluid circuit side to the blood circuit side by forced back-filtration through the hemodialyzer,
• a mechanism capable of repeating intermittently and at least a plurality of times an operation of flowing out a fluid from the blood circuit side to the dialysis fluid circuit side by filtration and the operation of flowing the fluid into the blood circuit side from the dialysis fluid side by back-filtration.