Systems and methods for compensation of compliant behavior in regenerative dialysis systems

A method of controlling ultrafiltration rate of a regenerative dialysis system, comprising:

• pumping fresh dialysate fluid into a dialyzer at an input rate;
• pumping used dialysate fluid from the dialyzer at an output rate, an ultrafiltration rate of the regenerative dialysis system being related to the output rate relative to the input rate;
• filtering the used dialysate fluid to generate the fresh dialysate fluid at a sorbent cartridge;
• and
• controlling the ultrafiltration rate of the regenerative dialysis system in response to a compliance model of the sorbent cartridge that provides a predefined model of compliant behavior related to the sorbent cartridge based on a relationship between a volume of dialysate fluid stored by the sorbent cartridge as a function of a flow rate of the dialysate fluid through the sorbent cartridge.

A regenerative dialysis system, comprising:

• an input pump that pumps fresh dialysate fluid into a dialyzer at an input rate;
• an output pump that pumps used dialysate fluid from the dialyzer at an output rate, an ultrafiltration rate of the system being related to the output rate relative to the input rate;
• a sorbent cartridge that filters the used dialysate fluid to generate the fresh dialysate fluid;
• a controller that controls the ultrafiltration rate of the system in response to a flow rate of the dialysate fluid through the sorbent cartridge, wherein the controller controls the ultrafiltration rate of the system in response to a corrected dialysate fluid weight;
• a reservoir that stores the fresh dialysate fluid;
• a scale that monitors the scale weight of the fresh dialysate fluid stored in the reservoir, wherein the controller further controls the ultrafiltration rate in response to the scale weight of the fresh dialysate fluid in the reservoir, wherein the controller further:
• calculates a dynamic weight of dialysate fluid stored in the sorbent cartridge in response to the flow rate of the dialysate fluid through the sorbent cartridge;
• calculates the corrected dialysate fluid weight by summing the dynamic weight and the scale weight;
• calculates an absorption weight of dialysate fluid stored in the sorbent cartridge as a result of time-based absorption;
• and
• calculates the corrected dialysate fluid rate by further summing the absorption weight with the dynamic weight and the scale weight.

A method of controlling ultrafiltration rate of a regenerative dialysis system, comprising:

• pumping fresh dialysate fluid into a dialyzer at an input rate;
• pumping used dialysate fluid from the dialyzer at an output rate, an ultrafiltration rate of the regenerative dialysis system being related to the output rate relative to the input rate;
• filtering the used dialysate fluid to generate the fresh dialysate fluid at a sorbent cartridge;
• controlling the ultrafiltration rate of the regenerative dialysis system in response to a flow rate of the dialysate fluid through the sorbent cartridge, and in response to a corrected dialysate fluid weight;
• storing the fresh dialysate fluid at a reservoir;
• monitoring the scale weight of the fresh dialysate fluid stored in the reservoir;
• further controlling the ultrafiltration rate in response to the scale weight of the fresh dialysate fluid in the reservoir;
• calculating a dynamic weight of dialysate fluid stored in the sorbent cartridge in response to the flow rate of the dialysate fluid through the sorbent cartridge;
• calculating the corrected dialysate fluid weight by summing the dynamic weight and the scale weight;
• calculating an absorption weight of dialysate fluid stored in the sorbent cartridge as a result of time-based absorption;
• and
• calculating the corrected dialysate fluid rate by further summing the absorption weight with the dynamic weight and the scale weight.