This disclosure relates to a method for determining a fluid balance between a first volume flow in a first section of a fluid circuit and a second volume flow of a second section of the fluid circuit. The method may also include adjusting, assuming or detecting a first temperature in the first section of the fluid circuit and a second temperature in the second section of the fluid circuit, or detecting a temperature difference between the first and the second sections. The method may also include detecting a second volume flow in a second section of the fluid circuit and forming a balance from at least the first volume flow and a corrected value of the second volume flow. The corrected value is determined from the detected second volume flow and the second temperature and/or the temperature difference.

A blood purification apparatus which can perform actions and operations according to the final stage of blood-return. Accordingly, a blood purification apparatus comprising a blood circuit including an arterial blood circuit and a venous blood circuit for extracorporeally circulating blood of a patient from a tip end of the arterial blood circuit to a tip end of the venous blood circuit; a blood purification means arranged between the arterial blood circuit and the venous blood circuit of the blood circuit and purifying blood flowing through the blood circuit; a substitution solution supplying means for supplying substitution solution to the blood circuit; and performing blood-return by substituting the blood in the blood circuit with the substitution solution supplied from the substitution solution supplying means after the blood purification treatment wherein the blood purification apparatus comprises a detecting means arranged at predetermined positions in the arterial blood circuit and the venous blood circuit and detecting presence or absence or blood concentration of the blood flowing in the arterial blood circuit and the venous blood circuit at said predetermined positrons, and a recognition means for recognizing a final stage of blood-return which is a condition near the end of the substitution of blood with the substitution solution based on the presence or absence of the blood or blood concentration detected by the detecting means.

The disclosure relates to a dialysis machine that comprises a dialyzer, a fluid source, a first line connected to the fluid source, and a container containing bicarbonate. The container connects to the first line and the fluid flows from the fluid source, through the first line, to the container. The dialysis machine further includes a second line connected to the container, a flow rate sensor connected to at least one of the lines, a pressure sensor configured for detecting fluid pressure of the container, a display, and a data processing apparatus. The data processing apparatus is configured to receive signals from the flow rate sensor and the pressure sensor. The data processing apparatus is configured to calculate a size of the container based on the received signals.

The disclosure relates to a method including determining a treatment time of a dialysis treatment for a patient, receiving, from at least a sensor of a dialysis machine, a dialysate flow rate, the dialysate comprising bicarbonate pumped out of a bicarbonate source, wherein the bicarbonate source has an initial amount of bicarbonate, and predicting that by end of the dialysis treatment no more than a threshold amount of bicarbonate will be left in the bicarbonate source, and in response, determining that a clearance value during the treatment is or will be higher than the threshold clearance value, and sending, to a balancing system, an instruction to reduce the dialysate flow rate to a reduced rate, wherein the reduced rate results in reducing a rate of bicarbonate pumped out of the bicarbonate source while maintaining a clearance value of the treatment at no less than the threshold clearance value.

The invention relates to a device and a method for detecting the direction of fluid flow through a dialyser 1 which comprises a blood chamber 4, through which blood flows, and a dialysate chamber 3, through which dialysate flows, which are separated from one another by a semi-permeable membrane 2. In addition, the invention relates to an extracorporeal blood treatment device comprising a device for detecting the flow direction. A first aspect of the invention is to measure the clearance in order to detect the flow direction and to compare the measured clearance with a specified limit value, a flow direction in countercurrent flow being concluded if the clearance is greater than the specified limit value. This aspect is based on the finding that in the case of blood treatment in practice with operation of the dialyser in co-current flow, clearance values above a certain limit value can no longer be achieved. A second aspect of the invention is to measure the clearance to detect the flow direction and to change the flow rate of the dialysate. Checking the flow direction according to the second aspect is based on the comparison of the measured change in clearance with a calculated expected value of the change in clearance for operation of the dialyser in both countercurrent flow and co-current flow. The invention according to the second aspect is based on the finding that the amount of the relative change in clearance in the event of a change in dialysate rate is always greater in the case of operation in co-current flow than in countercurrent flow.

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 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).

A method and a device for determining a recirculation during a dialysis on the basis of the response of the dialysis system to an alteration of a system-related operating value are described. Recirculation may be determined by establishing, at the side of the dialysis liquid, a reference parameter that represents the concentration of uremic toxins from the extracorporeal circulation, and calculating a target parameter for a system-related target operational value from the reference parameter, presetting the system-related target operational value and establishing an actual parameter related to the system-related target operational value, determining an actual comparative value from the actual parameter and the reference parameter related to the system-related target operational value and comparing the actual comparative value with a system-specific target comparative value related to the system-related target operational value, and converting the comparison result into a recirculation degree.

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 (STMP.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 (STMP.sub.2) which is greater than the first increase (STMP.sub.1).

An apparatus (1a) for extracorporeal blood treatment, comprising an infusion control arrangement (8) arranged for infusing a pre-dilution flow rate upstream a blood treatment unit (4) and a post-dilution flow rate downstream the blood treatment unit (4), an ultrafiltration, UF, arrangement (40) arranged for ultrafiltration of a liquid through a semipermeable membrane (7) of the blood treatment unit (4) and a control unit (31). The control unit (31) is configured to configure the infusion control arrangement (8) to obtain a plurality of different configurations of the pre-dilution flow rate and/or post-dilution flow rate. For each of the plurality of different configurations, the control unit (31) is configured to change an operating situation of the UF arrangement (40), to detect a plurality of ultrafiltration flow rate values through the membrane (7) as a function of TMP, on changing said operating situation, and to evaluate an optimal ultrafiltration flow rate value from a comparison of the detected ultrafiltration flow rates. The apparatus (1a) is also configured to estimate a clearance value for a certain solute at the optimal ultrafiltration flow rate value and to evaluate a preferred configuration of the pre-dilution flow rate and/or post-dilution flow rate from a comparison of the corresponding estimated clearance values.