Blood purification apparatus

A blood purification apparatus comprising:

• a blood circuit including an arterial blood circuit and a venous blood circuit and that allows a patient's blood to extracorporeally circulate, with a blood purifier that is interposed between the arterial blood circuit and the venous blood circuit and purifies the patient's blood;
• a pre-substitution line through which substitution fluid is introduced into the arterial blood circuit for pre-substitution;
• a post-substitution line through which the substitution fluid is introduced into the venous blood circuit for post-substitution;
• a substitution line having one end connected to a substitution-fluid source capable of supplying the substitution fluid, and an other end connected to the pre-substitution line and to the post-substitution line;
• substitution pumps that deliver the substitution fluid in the substitution-fluid source from the substitution line through at least one of the pre-substitution line and the post-substitution line to at least one of the arterial blood circuit and the venous blood circuit;
• a control unit that controls the substitution pumps,
• a heating bag to be heated by a heating device and including a portion of the substitution line, the heating bag being attached to a position of the substitution line that is between a first substitution pump and a branching part of the pre-substitution line and the post-substitution line;
• an air trap chamber, wherein the substitution line is provided with the air-trap chamber at a position between the heating device and the arterial blood circuit or the venous blood circuit, the air-trap chamber being capable of trapping bubbles in the substitution fluid;
• wherein the substitution pumps are each a peristaltic pump that deliver liquid by squeezing a flexible tube forming a flow route for the substitution fluid, and include a first substitution pump provided to the substitution line, and a second substitution pump provided to one of the pre-substitution line and the post-substitution line,
• the blood purification apparatus further comprises:
• a check valve provided to one of the pre-substitution line and the post-substitution line, wherein the check valve is located within the post-substitution line between the air-trap chamber and a dialyzer;
• and
• a pressure sensor that detects a fluid pressure in a portion between the first substitution pump and the second substitution pump in the substitution line, the pre-substitution line, and the post-substitution line;
• wherein the control unit corrects a driving speed of the first substitution pump or the second substitution pump in accordance with the fluid pressure detected by the pressure sensor to remove a negative pressure or a positive pressure generated in the portion of the flow route for the substitution fluid between the first substitution pump and the second substitution pump in the substitution line, the pre-substitution line, and the post-substitution line.