Blood purification apparatus and priming method thereof

A blood purification apparatus comprising:

• a blood circuit including an arterial blood circuit and a venous blood circuit for extracorporeally circulating the blood of a patient from a tip of the arterial blood circuit to a tip of the venous blood circuit;
• dialyzer for purifying the blood of a patient flowing through the blood circuit interposed between the arterial blood circuit and the venous blood circuit of the blood circuit and formed with a blood flow route through which the blood of a patient flows and a dialysate flow route through which dialysate flows via blood purification membranes arranged therebetween;
• a blood pump arranged in the arterial blood circuit;
• a dialysate introducing line and a dialysate discharging line connected respectively to an inlet port and an outlet port of the dialysate flow route of the blood purification means;
• a priming solution supplying line connected to the arterial blood circuit for supplying priming solution to the blood circuit;
• a blood inlet port and a blood outlet port arranged at opposite ends of the dialyzer, the blood inlet port being connected to the arterial blood circuit for introducing the blood therefrom into the blood flow route within the blood purification means and the blood outlet port being connected to the venous blood circuit for discharging the blood from the blood flow route within the dialyzer;
• a dialysate inlet port and a dialysate outlet port arranged at the side of the dialyzer, the dialysate inlet port being connected to the dialysate introducing line for introducing the dialysate therefrom into the dialysate flow route within the dialyzer and the dialysate outlet port being connected to the dialysate discharging line for discharging the dialysate from the dialysate flow route within the dialyzer;
• a drip chamber connected to the venous blood circuit;
• an overflow line extending from an air layer side of the drip chamber for discharging overflowed solution from the drip chamber;
• a valve means being able to arbitrarily open and close the overflow line;
• a venous bubble detecting means arranged at a predetermined portion near the tip of the venous blood circuit for detecting bubbles in the solution flowing through the predetermined portion;
• and
• a closed circulation circuit being able to be formed by connecting the tip of the arterial blood circuit and the tip of the venous blood circuit when performing the priming operation before the dialysis treatment
• a control means configured and arranged to control the blood pump and the valve means and receive detecting signals from the venous bubble detecting means;
• wherein the control means is configured and arranged to perform sequentially, during the priming operation, steps under a condition in which the blood inlet port of the dialyzer is set at a top position, said steps comprising:
• an overflowing step in which the priming solution is supplied to the drip chamber from the priming solution supplying line via the venous blood circuit and then discharged through the over flow line by stopping the blood pump and opening the valve means;
• a circulating step in which the priming solution is supplied to the arterial blood circuit from the priming solution supplying line via the venous blood circuit and the dialyzer by driving the blood pump in reverse and closing the valve means;
• and
• a shifting step for shifting the circulating step to the overflowing step so long as the venous bubble detecting means detects bubbles.