The invention relates to a method and to a device for determining an optimum dialysate flow Q.sub.dopt for an extracorporeal blood treatment and to a blood treatment device comprising a device 18 for determining an optimum dialysate flow Qd.sub.opt. The optimum dialysate flow Qd.sub.opt is determined on the basis of a relationship describing the dependence of the clearance K on the dialysate flow Q.sub.d. The device according to the invention comprises a measurement device 18B for measuring at least one value which is characteristic of the clearance K, a calculation and/or evaluation unit 18A of the device according to the invention being configured in such a way that the clearance K is determined on the basis of the at least one value which is characteristic of the clearance. The calculation and/or evaluation unit 18A is configured in such a way that the optimum dialysate flow Q.sub.dopt is determined from the relationship describing the dependence of the clearance K on the dialysate rate Q.sub.d on the basis of the measured clearance K, or the optimum dialysate flow Q.sub.dopt is determined from the measured clearance K.

A device for determining the access flow rate of a patient when connected to a blood treatment machine performs a measurement phase (40), in which the blood treatment machine is caused (41, 43) to operate in first and second operating states, wherein the second operating state at least differs from the first operating state by a change of flow direction of blood or treatment fluid through a dialyzer of the blood treatment machine. Based on sensor values representing a fluid property (42, 44) of the treatment fluid in the first and second operating states, the device computes (45) a measurement value of comparison parameter (e.g. a ratio or a difference) that compares treatment efficiency in the first operating state to treatment efficiency in the second operating state, and determines (46), based on the measurement value, an estimated value of the access flow rate.

The disclosed subject matter relates to extracorporeal blood processing or other processing of fluids. Volumetric fluid balance, a required element of many such processes, may be achieved with multiple pumps or other proportioning or balancing devices which are to some extent independent of each other. This need may arise in treatments that involve multiple fluids. Safe and secure mechanisms to ensure fluid balance in such systems are described.

The disclosed subject matter relates to extracorporeal blood processing or other processing of fluids. Volumetric fluid balance, a required element of many such processes, may be achieved with multiple pumps or other proportioning or balancing devices which are to some extent independent of each other. This need may arise in treatments that involve multiple fluids. Safe and secure mechanisms to ensure fluid balance in such systems are described.

An extracorporeal blood treatment apparatus is provided comprising a filtration unit (2) connected to a blood circuit (17) and to a dialysate circuit (32); a control unit (12) is configured for calculating a sodium concentration value for the blood; the estimation of the sodium concentration includes the sub-step of calculating the sodium concentration value as an algebraic sum of a main contribution term based on the isoconductive sodium concentrate and of an offset contribution term based on a concentration of at least a substance in the dialysis fluid chosen in the group including bicarbonate, potassium, acetate, lactate, citrate, magnesium, calcium, sulphate and phosphate.

A portable hemodialysis system is provided including a dialyzer, a closed loop blood flow path, a closed loop dialysate flow path, a blood pump, and a pair of dialysate pumps. A processor controls the flow of blood through the blood flow path, and the processor controls the flow of dialysate through the dialysate flow path. In addition, the processor stores a preprogrammed patient treatment plan wherein the flow rate of the dialysate through the dialysate flow path reduces throughout the patient's treatment to maximize the amount of urea removed by the sorbent filter. In alternative embodiments, the processor stores a patient treatment plan wherein the dialysate flow rate increases throughout the patient's treatment. In still alternative embodiments, the processor stores a patient treatment plan wherein the flow rate of the dialysate through the dialysate flow path both increases and decreases throughout the patient's treatment.

Systems, methods, and/or apparatuses may be operative to perform a dialysis process that includes a displacer infusion process. The dialysis machine may include at least one processor and a memory coupled to the at least one processor, the memory comprising instructions that, when executed by the processor, may cause the at least one processor to access dialysis information for a dialysis process performed by a dialysis machine, the dialysis information indicating a target substance to be displaced from a binding compound by a displacer, and determine an infusion profile for infusing the displacer into a patient during a displacer infusion process of the dialysis process, the infusion profile determined based on the dialysis information and an infusion constraint. Other embodiments are described.

Systems, methods, and/or apparatuses may be operative to perform a dialysis process that includes a displacer infusion process. The dialysis machine may include at least one processor and a memory coupled to the at least one processor, the memory comprising instructions that, when executed by the processor, may cause the at least one processor to access dialysis information for a dialysis process performed by a dialysis machine, the dialysis information indicating a target substance to be displaced from a binding compound by a displacer, and determine an infusion profile for infusing the displacer into a patient during a displacer infusion process of the dialysis process, the infusion profile determined based on the dialysis information and an infusion constraint. Other embodiments are described.

An apparatus for extracorporeal blood treatment, comprising a treatment unit (2) having a first chamber (3) and a second chamber (4) separated from one another by a semipermeable membrane (5), a blood removal line (6) connected in inlet with the first chamber (3) and a blood return line (7) connected in outlet with the first chamber; an infusion line (9;9a, 9b) of a replacement fluid and a fluid evacuation line (10) connected in outlet from the second chamber. A regulating device (20) of a transmembrane pressure is active on at least one of the lines and a control unit (15) is configured to: command the regulating device (20) by setting a first increase (TMP.sub.1), determine a value of a control parameter (.sub.1) corresponding to the first increase, compare the value of the control parameter (.sub.1) with a reference value (.sub.ref) and, if the value of the control parameter is greater than the reference value, command the regulating device (20) by setting a second increase (TMP.sub.2) which is greater than the first increase (TMP.sub.1).

An extracorporeal blood treatment apparatus is provided comprising a filtration unit (2) connected to a blood circuit (17) and to a dialysate circuit (32), a preparation device (9) for preparing and regulating the composition of the dialysis fluid; a control unit (12) is configured for setting a sodium concentration value for the dialysis fluid in the dialysis supply line (8) at a set point; the setting of the sodium concentration includes the sub-step of calculating the sodium concentration value as an algebraic sum of a main contribution term based on the blood plasma conductivity and of an adjustment contribution term based on a concentration of at least a substance in the dialysis fluid chosen in the group including bicarbonate, potassium, acetate, lactate, citrate, magnesium, calcium, sulphate, and phosphate.