The present invention relates to medical fluid treatments, such as the treatment of renal failure. More specifically, the present invention relates to the testing of such systems.

A dialysis machine has a blood circuit, a blood pump, a dialyzer, a venous pressure sensor, a substituate line, and a control unit. The control unit can operate the blood pump in a first operating mode and in a special operating mode, and start the special operating mode after a trigger event. In the special operating mode, a blood pump conveying rate is controlled via a default value or regulated to a desired value, with the default or desired value being derived from a value determined before the started special mode or corresponding to the value. The presence of an obstacle is polled before the special mode, and depending on the presence thereof, the start of the special mode is blocked or delayed and/or the selection of the default value or the desired value on the presence of the obstacle differs from the selection without the presence of the obstacle.

An apparatus and a method for extracorporeal blood treatment, especially for hemodialysis, wherein blood of a patient is flushed with a dialysate in a dialyzer and wherein a variable correlated with the plasma sodium concentration of the blood is measured. The composition of the dialysate then is adjusted in response to the variable measured so that the plasma sodium concentration of the blood at least at the end of the blood treatment has the same value as at the beginning. For measuring the variable correlated with the plasma sodium concentration of the blood, for example a bypass operation can be implemented in which the dialysate is guided past the dialyzer so that a residual volume on the side of the used dialysate at least partially adopts the concentration of the substances dissolved on the blood side.

The present invention relates to medical fluid treatments, such as the treatment of renal failure. More specifically, the present invention relates to the testing of such systems.

A method of identifying a type of a filter, which has at least one retentate side and at least one permeate side separated from one another by at least one filter medium, includes generating a pressure in a fluid, in particular in a liquid, on the retentate side or on the permeate side via a pressure source. The method then includes switching off the pressure source, and measuring a pressure development in the fluid over time subsequent to the switching off of the pressure source.

The present disclosure relates to a method for determining an actual pump rate and/or for calibrating a blood pump of a blood treatment apparatus connected to an extracorporeal blood circuit. The method includes providing a blood pump of a blood treatment apparatus or establishing a signal communication to a blood pump. The blood pump comprises, or is connected to at least a first source for a fluid and at least a first line of an extracorporeal blood circuit which is connected to the first source downstream. Furthermore, the blood pump comprises, or is connected to, a reception unit for receiving fluids of the first source wherein the reception unit is in fluid communication with the first line. The reception unit is arranged on or at a first weighing device such that the weight of the reception unit or of its content is determined using the weighing device.

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.

An electrical sensor for sensing electromagnetic properties of process fluids in a dialysis machine or a similar medical device can include a probe for interfacing with the fluids that is made from electronic fabric materials. The electronic fabric probe can include one or more conductors embedded in a non-conductive fabric layer. The electronic fabric probe is accommodated an enclosure which establishes a flow path with respect to the probe to establish fluid contact between the process fluids and the conductors. The conductors can apply or sense current and/or voltage with respect to the fluid. A portion of the electronic fabric probe can be disposed externally of the enclosure to provide electronic communication externally of the enclosure.

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.

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.