Renal failure therapy machines and methods including convective and diffusive clearance

A renal failure therapy machine comprising:

• a blood circuit including a blood cleaning filter;
• a dialysis fluid circuit including a balance chamber, the balance chamber including a fresh dialysis fluid compartment configured to send fresh dialysis fluid to the blood cleaning filter and a used dialysis fluid compartment configured to receive used dialysis fluid from the blood cleaning filter;
• a valve located along a fresh dialysis fluid pathway placing the fresh dialysis fluid compartment of the balance chamber into fluid communication with the blood cleaning filter, the valve enabling fresh dialysis fluid to flow selectively from the fresh dialysis fluid compartment of the balance chamber to the blood cleaning filter;
• and
• a flow restrictor in fluid communication with the blood cleaning filter, the flow restrictor configured to cause fresh dialysis fluid pumped past the valve to the blood cleaning filter to be pressurized so that a first amount of the fresh dialysis fluid performs convective clearance and a second amount of the fresh dialysis fluid performs diffusive clearance.

A renal failure therapy method comprising:

• delivering fresh dialysis fluid from a fresh dialysis fluid compartment of a balance chamber to a blood cleaning filter;
• pumping used dialysis fluid from the blood cleaning filter to a used dialysis fluid compartment of the balance chamber;
• restricting flow to cause a first amount of fresh dialysis fluid to be pressed through a membrane of the blood cleaning filter into an extracorporeal circuit so that the first amount of the fresh dialysis fluid performs convective clearance;
• and
• using a second amount of the fresh dialysis fluid to cause the blood cleaning filter to perform diffusive clearance.