Apparatus for blood dialysis and filtration

A hemodiafiltration apparatus for performing extraction and reinfusion of blood alternately and intermittently by using one puncture needle, comprising:

• a hemodialyzer in which blood and a dialysis fluid are brought into contact with each other through a porous membrane to purify blood;
• an arterial side blood circuit in communication with a patient via said one puncture needle and in communication with the hemodialyzer:
• a venous side blood circuit in communication with the patient via said one puncture needle and in communication with the hemodialyzer;
• wherein the arterial side blood circuit, the venous side blood circuit, and a first side of the hemodialyzer comprise a patient side of the apparatus;
• a dialysis fluid supply line through which a dialysis fluid is supplied to the hemodialyzer;
• a dialysis fluid discharge line through which the dialysis fluid is discharged from the hemodialyzer;
• a blood pump provided in one of the arterial side blood circuit and the venous side blood circuit, the blood pump providing a blood flow at a preselected flow rate and operable in a normal direction and an opposite direction;
• a supply delivery means for supplying the dialysis fluid provided in the dialysis fluid supply line;
• a discharge delivery means for discharging the dialysis fluid provided in the dialysis fluid discharge line;
• a filtration/back-filtration fluid supply means provided in parallel with the supply delivery means for supplying the dialysis fluid, the filtration/back-filtration fluid supply means operable in normal and opposite directions, the filtration/back-filtration fluid supply means providing a flow of fluid in the hemodialyzer at a preselected flow rate;
• wherein the dialysis fluid supply line, the dialysis fluid discharge line;
• the supply delivery means, the discharge delivery means, and the filtration/back-filtration fluid supply means comprise a hemodialysis side of the apparatus;
• and
• a control means for controlling the filtration/back-filtration fluid supply means by issuing a series of instructions to the filtration/back-filtration fluid supply means, the series of instructions comprising a cycle repeated a predetermined number of times, the instructions including:
• an instruction directing the filtration/back-filtration fluid supply means to operate in a flow direction opposite to a flow direction of a supply delivery means for supplying the dialysis fluid for a preset, predetermined period of time to perform the extraction of blood from the body of the patient;
• an instruction directing the filtration/back-filtration fluid supply means to stop operating for a preset, predetermined period of time to purify blood through diffusion by counterflow with the dialysis fluid;
• an instruction directing the filtration/back-filtration fluid supply means to operate in a flow direction that is the same as a flow direction of the supply delivery means for supplying the dialysis fluid for a preset, predetermined period of time that is shorter than the period of time for the extraction of blood to perform a reinfusion of blood to the body of the patient;
• and an instruction directing the filtration/back-filtration fluid supply means to stop operating for a preset, predetermined period of time to purify blood through diffusion by a counterflow with the dialysis fluid.