Dialysis machine comprising a mixing system for preparing a dialysis solution

Abstract

The invention relates to a dialysis machine comprising a mixing system for preparing a dialysis solution by admixing at least one first and optionally one second component to a liquid supplied to the dialysis machine. The invention also relates to a method. The dialysis apparatus comprises: a first pump for conveying the first component; a controller for controlling the first pump; and a protection system for monitoring the dialysis solution. The protection system comprises a conductivity sensor which measures the conductivity of the dialysis solution. The protection system prompts the controller to interrupt an ongoing treatment if the conductivity measured by the first conductivity sensor deviates from a specified conductivity range, and the controller accesses the conductivity measured by the first conductivity sensor of the protection system, and the first pump is controlled by means of a feedback loop by feeding back the measured conductivity as a control variable.

Description

[0001] Dialysis machine with a mixing system for producing a dialysis solution

[0002] The present invention relates to a dialysis machine with a mixing system for producing a dialysis solution.

[0003] The online production of a dialysis solution in the dialysis machine can be carried out, for example, by admixing at least a first and a second component to the (ultrapure) water supplied to the dialysis machine via a water connection, in particular by admixing two or three concentrates such as a bicarbonate concentrate and an acid concentrate and / or sodium concentrate.

[0004] There are at least two methods by which the admixture of concentrates can be controlled during the preparation of the dialysis solution:

[0005] With volumetric mixing, the controller determines how much concentrate is added. This requires very precise pumps (e.g., diaphragm pumps) to ensure that the specified dosage is maintained. Volumetric mixing can also include measuring the conductivity of the concentrate to determine its concentration. However, there is no pump control using the conductivity of the produced mixture as the control variable. Rather, the conductivity measurement serves only as a monitoring function.

[0006] In conductivity-controlled mixing, on the other hand, the conductivity of the mixture produced is continuously measured (control variable) and the pump is operated by feedback of the control variable in a control loop so that a target conductivity is achieved.

[0007] The individual concentrates are usually mixed one after the other into a main line carrying water, so that the conductivity of the mixture of the first mixed concentrate is determined separately by means of a conductivity sensor arranged downstream of a mixing point of the first mixed concentrate and upstream of a mixing point of the subsequently mixed concentrate, and the dosage can be controlled on the basis of the measured value of the conductivity sensor.

[0008] In both cases, the dialysis machine can have a protection system that allows monitoring individually for each concentrate admixture to ensure that the concentrates are mixed correctly.

[0009] Exemplary systems are known from the documents DE 10 2018 121080 A1 and US 2010 282834 A1.

[0010] Typically, the following components are required for a system that mixes water, bicarbonate concentrate, and acid concentrate to form a ready-to-use dialysis solution, where the bicarbonate is usually an aqueous solution of sodium bicarbonate only and the acid concentrate is usually an aqueous solution of an acid, optionally with other electrolytes and / or glucose and / or amino acids:

[0011] For volumetric mixing: a pump for water, a pump for bicarbonate, a conductivity sensor for the bicarbonate / water mixture as a protection system, a pump for the acid concentrate, and a conductivity sensor for the bicarbonate / water / acid mixture, i.e., a ready-to-use dialysis solution, as a protection system. Furthermore, a conductivity sensor can be additionally installed upstream of the bicarbonate pump or between the bicarbonate pump and the water mixing point, since the bicarbonate concentrate is usually first produced in the device, and the concentration depends on the dissolution behavior, temperature, etc., so it cannot be specified as a fixed value. This is different with the acid concentrate, since a ready-to-use liquid solution with a defined concentration is regularly used, and there is no risk of the concentration changing due to the prevailing ambient conditions.

[0012] For the conductivity-controlled mixture: pump for water, pump for bicarbonate, conductivity sensor for the bicarbonate / water mixture for controlling the bicarbonate pump, conductivity sensor for the bicarbonate / water mixture as a protection system, pump for acid concentrate, conductivity sensor for the bicarbonate / water / acid mixture for controlling the acid concentrate pump, conductivity sensor for the bicarbonate / water / acid mixture as a protection system.

[0013] Conductivity-controlled mixing allows for more precise dosing of the concentrates. Potentially, slightly less precise pumps can be used, which can then be more cost-effective. However, the equipment required for conductivity-controlled mixing is greater because conductivity sensors are required to control the pumps. Another challenge with conductivity-controlled mixing is the additional need to ensure that patient safety is not compromised, even if an undetected error or malfunction occurs.

[0014] The object of the present invention is therefore to provide a dialysis machine with a mixing system for producing a dialysis solution, which allows for reliable mixing and in which the equipment complexity can be reduced. This object is achieved by a system according to claim 1 and a method according to claim 15. Preferred embodiments of the present invention are the subject of the dependent claims.

[0015] Furthermore, in addition to the subject matter of claim 1, the present invention also comprises further subject matters which are independent of this part of the present invention and are also described in more detail below.

[0016] In a first aspect, the present invention comprises a dialysis machine with a mixing system for producing a dialysis solution by admixing at least a first and optionally a second component to a liquid supplied to the dialysis machine, in particular water, comprising: a first pump for conveying the first component, in particular an acid and / or sodium concentrate, and optionally a second pump for conveying the second component, in particular a bicarbonate concentrate, a controller for controlling the first and optionally the second pump, and a protection system for monitoring the dialysis solution, wherein the protection system comprises a first conductivity sensor which measures the conductivity of the dialysis solution.The first aspect is characterized in that the controller accesses the conductivity measured by the first conductivity sensor of the protection system and controls the first pump by means of a control loop by feeding back the measured conductivity as a control variable.

[0017] The control system can be designed in such a way that the control of the first pump by the control system only takes place within a first predetermined permissible control range.

[0018] Alternatively or additionally, the controller can be designed such that the first pump is controlled by the controller only when the conductivity measured by the first conductivity sensor results in control within a first predefined permissible control range and / or when a controlled variable can be brought into a first predefined permissible control range by the control loop. The first predefined permissible control range can encompass the predefined conductivity range or be such a conductivity range, and / or the first predefined permissible control range can encompass a predefined range of permissible flow rates or be such a range.

[0019] According to a possible embodiment of the present invention, the control system is designed such that the control of the first pump is only carried out by the control system when no ongoing treatment is taking place.

[0020] Unless otherwise stated in the context of the description, the terms dialysis solution and dialysate are synonymous. A dialysis solution is a liquid used for or during dialysis and can be a solution that is not yet ready for treatment or a solution that is ready for treatment. A dialysate composition is accordingly a composition of a dialysis solution. A dialysate circuit comprises a line system through which dialysis solution is conducted and can further comprise additional line sections that are intended to conduct the dialysis solution, for example after it has been conducted through a dialyzer.

[0021] The controller can use the conductivity measured by the first conductivity sensor to control the first pump. The control can be carried out by the controller comparing the measured conductivity with a control range for the conductivity. Alternatively, a control range for the delivery rate of the first pump can be stored in the controller. For this purpose, the controller can be set up to use the conductivity to infer the composition of the solution and to determine by how much the delivery rate of the first pump needs to be changed in order to achieve a desired composition. and to establish whether this change in the delivery rate of the first pump lies outside a predefined permissible control range for the delivery rate. If this change lies outside the predefined permissible control range, the change in the delivery rate cannot take place or is not permitted, for example.Alternatively, the controller can gradually change the pump's flow rate. During this process, it checks whether the conductivity corresponds to a target or setpoint. If this is the case, the controller stops the stepwise change in the flow rate. If the control range is exceeded during the stepwise change without reaching the target or setpoint, the controller stops the stepwise change in the flow rate. The protection system intervenes by interrupting the treatment if the specified conductivity range is not reached or is exceeded.

[0022] This control is fundamentally based on the following consideration: When controlling the first pump, the decision as to whether control is permitted is based on a composition window, specifically a "sodium window," meaning that the subsequent control may only change the volumetric dosage by, for example, a certain percentage. In principle, due to the good proportionality between conductivity and composition, particularly the sodium concentration, this can also be formulated as a conductivity range. This involves a dialysate composition, with conductivity being a possible surrogate parameter for monitoring purposes.

[0023] The first conductivity sensor assigned to the protection system or the first conductivity sensor used for the protection system has the meaning that the measured value of the sensor is not used by the protection system to control the treatment, but to put the device into a state safe for the patient after detecting a deviation of the conductivity from a predetermined conductivity range, whereby this safe state can be a state in which the patient is not treated.For example, the supply of dialysis solution to the dialyzer can be interrupted and / or the dialysis solution can be bypassed past the dialyzer, for example via a bypass line. This can be done by closing a valve on the inlet to the dialyzer and opening a valve in the bypass line, thereby preventing an exchange in the dialyzer between the deviating dialysis solution and the blood, and / or the blood pump can be stopped and / or one or more clamps on the blood-carrying tubes can be closed. The protection system can further be designed such that, upon detection of a deviation, an alarm signal, for example an optical and / or acoustic signal, is emitted by the device, for example one or more of a signal from a light emitter of the device, a display of a message on a screen of the device, an acoustic tone from a loudspeaker of the device.The protection system can be designed so that, when the conductivity no longer deviates from the specified conductivity range, it automatically causes the device to resume treatment. This can be achieved by recirculating the dialysis solution through the dialyzer. This can be done by opening a valve at the inlet to the dialyzer and closing a valve in the bypass line, and / or starting the blood pump and / or opening one or more clamps on the blood-carrying tubes.

[0024] According to the invention, the first conductivity sensor assigned to the protection system or a first conductivity sensor used for the protection system is now also used to control the first pump for metering the first component.

[0025] This is a conceptually fundamentally different approach than systems in which the protection system is completely separate from the operating system or at least physically separate with regard to the production of the dialysis solution, so that the protection system with its components and / or the measured values ​​used for the protection system do not intervene in the operation of the device, except that the device is put into a state that is safe for the patient (e.g. interruption of a dialysis solution flow if the composition of the dialysis solution does not match the target values, issuance of messages, alarms).

[0026] According to embodiments of the invention, the protection system may no longer be physically separate, i.e. separate sensors may not be provided for the protection system and the operating system, but the protection system can still monitor the device independently of the operating system. In other words, the operating system can still intervene in the functions of the device to the extent that the independent protection system permits, whereby the possibilities for intervention can only lie within the framework of safe treatment. The inventors of the present invention have recognized that such use of the conductivity sensor assigned to the protection system to control a pump is possible without unacceptable losses in patient safety. This can reduce the equipment complexity and increase the availability of the device during operation, since any additional component can fail.In addition, it can simplify the operating software, since separate conductivity sensors will produce different readings even if they measure the same solution, so the software must ensure that it is actually the same solution.

[0027] According to the present invention, the first conductivity sensor is used to control the first pump for dosing the first component, in particular the acid and / or sodium concentrate.

[0028] According to the present invention, the first pump is therefore conductivity-controlled by feedback of the conductivity of the dialysis solution, in particular of the ready-mixed dialysis solution, measured by the first conductivity sensor.

[0029] The first conductivity sensor can be arranged to measure the conductivity of the pre-mixed dialysis solution. A pre-mixed dialysis solution can be a solution that is fed into a dialyzer during treatment without changing its composition.

[0030] According to a possible embodiment of the present invention, the dialysis machine further comprises a second conductivity sensor which measures the conductivity of a mixture comprising the liquid supplied to the dialysis machine, in particular water, and the second component, but not the first component, wherein the second pump is conductivity-controlled by feedback of the conductivity measured by the second conductivity sensor.

[0031] According to one possible embodiment of the present invention, the control system is designed such that the control of the first and / or second pump only occurs within a predefined permissible control range, in particular only within a predefined range of permissible flow rates and / or conductivity. This permissible control range can be selected such that the patient is not endangered by any possible activation of the pump within this range. The dialysis machine can therefore perform control within this range without posing any danger to the patient.

[0032] This second aspect of the control ranges is also the subject of the present invention independently of the first aspect of the split conductivity sensor, but can also be implemented in combination with the first aspect. The invention according to the second aspect comprises a dialysis machine with a mixing system for producing a dialysis solution by admixing at least a first and / or a second component to a liquid supplied to the dialysis machine, in particular water, comprising: a first pump for conveying the first component, in particular an acid and / or sodium concentrate, and / or a second pump for conveying the second component, in particular a bicarbonate concentrate, a controller for controlling the first and / or second pump, and a first conductivity sensor which measures the conductivity of a mixture comprising the first and / or second component, and in particular the conductivity of the dialysis solution.The controller accesses the conductivity measured by the first conductivity sensor and controls the first and / or second pump by means of a control loop by feeding back the measured conductivity as a control variable. The second aspect is characterized in that the controller is designed such that the control of the first and / or second pump only takes place within a predetermined permissible control range, in particular only within a predetermined range of permissible flow rates and / or conductivities. The advantages described above also arise when the first conductivity sensor is not part of the protection system.

[0033] All features described above with regard to the first aspect also form the second aspect in an identical manner in possible embodiments of the present invention, without the first conductivity sensor necessarily being part of the protection system. In particular, the first conductivity sensor can be used to control the first pump for metering the first component, in particular the acid and / or sodium concentrate.

[0034] The control system can also be designed in other ways, and in particular, control the first and second pumps as described above with regard to the first aspect. However, the first conductivity sensor does not have to be part of the protection system.

[0035] Preferred embodiments of both the first and second aspects are described below.

[0036] According to one possible embodiment of the present invention, the control system is designed such that the control of the first and / or second pump occurs only within a predetermined permissible control range, in particular only within a predetermined range of permissible delivery rates and / or a predetermined conductivity range. Preferably, the predetermined conductivity range lies within the range or is the range outside of which the protection system sets the device to a state safe for the patient.

[0037] According to one possible embodiment of the present invention, the protection system is designed such that it only switches the device to a safe state for the patient when the conductivity lies outside the specified conductivity range for a predetermined period of time. This prevents short-term fluctuations from leading to treatment termination.

[0038] The further the measured conductivity is from the conductivity range, the shorter the specified time can be.

[0039] According to one possible embodiment of the present invention, the control system is designed such that the first and / or second pump is additionally or only conductivity-controlled under predetermined conditions when the conductivity lies outside the predetermined conductivity range. According to one possible embodiment of the present invention, the control system is particularly designed such that the control of the first and / or second pump is conducted in a conductivity-controlled manner when the control system has previously calculated that, by utilizing the permissible control range, the conductivity can be shifted into the predetermined conductivity range, wherein the predetermined conductivity range is the range outside of which the protection system puts the device into a state safe for the patient, optionally after a predetermined time.

[0040] According to another possible embodiment of the present invention, the control is designed in particular such that the control of the first and / or second pump is carried out in a conductivity-controlled manner if a measured shift in the conductivity achieved within the scope of the control is a shift of the actual value in the direction of the predetermined conductivity range and the predetermined conductivity range is the range outside of which the protection system puts the device into the state safe for the patient, optionally after a predetermined time.

[0041] Further preferred embodiments of the independent aspects described so far are described below.

[0042] According to one possible embodiment of the present invention, the predetermined permissible control range for the first and / or the second pump, in particular for the first pump, is less than + / - 20% of an average value of the permissible control range, preferably less than + / - 10%. For example, a control range of + / - 5% of an average value of the permissible control range can be provided. The relatively small permissible control range ensures that the patient cannot be endangered. The effect of these control ranges should preferably be selected such that no negative effects or negatively perceived effects on the patient arise, or at least no negative effects occur within medically justifiable limits. The smaller the control range selected, the lower the probability that such a negative effect will occur.A control range of + / - 5% has proven to be unproblematic in all cases; wider control ranges are not necessarily expected to have negative effects. In particular, the control ranges can be more or less problematic depending on the patient, so they can be adjusted on the dialysis machine, especially for each patient. The control range(s) can be set by the controller so that they always extend only from the actual value toward the target value. This can prevent control that would lead to a significant deviation of the actual value from the target value.

[0043] According to a possible embodiment of the present invention, the control comprises a volume-based pre-control of the first and / or second pump, which determines a desired delivery rate and / or control variable on the basis of the specifications of a prescription and / or on the basis of data on the component used and uses it to pre-control the first and / or second pump, wherein the control adjusts the desired delivery rate and / or control variable within a permissible control range based on conductivity.

[0044] Preferably, the permissible control range surrounds the delivery rate determined by the pilot control and thus prevents the control from changing the delivery rate determined by the pilot control by more than a permissible value.

[0045] According to a possible embodiment of the present invention, the control is designed such that the mean value of the permissible control range and / or the permissible control range and / or the conductivity range is determined as a function of a prescription which is given to the dialysis machine, for example via a patient card.

[0046] According to one possible embodiment of the present invention, the permissible control range for the second pump is larger than the permissible control range for the first pump. In particular, the permissible control range for the admixture of the second component, and in particular the bicarbonate concentrate, is larger than the permissible control range for the admixture of the first component, and in particular the acid and / or sodium concentrate. This takes into account the fact that the concentration of the bicarbonate concentrate, which is often only produced in the device, can fluctuate more significantly, so that a larger control range can lead to higher availability of the device. In particular, the size of the control ranges is considered as a percentage deviation from an average value of the control range.

[0047] According to one possible embodiment of the present invention, the controller stores permissible control ranges of varying sizes, which the controller uses to control the first and / or second pump depending on the currently used source of the component. In particular, the controller uses permissible control ranges of varying sizes for controlling the second pump depending on the currently used source of the second component. In this way, the controller takes into account that the concentration of the second component, and in particular of the bicarbonate concentrate, can fluctuate to varying degrees depending on the source from which it is currently being drawn.If the second component, and in particular the bicarbonate concentrate, is not produced in the dialysis machine but is provided as a ready-made solution from a canister or other source, fluctuations in the concentration are not to be expected, so that a correspondingly smaller permissible control range can be used.

[0048] According to one possible embodiment of the present invention, the currently used source of the component can be entered via a user interface and / or automatically detected by the controller. For example, automatic detection can be achieved by the device having a sensor for detecting that a specific container is connected to the fluid circuit. The sensor can be a camera, a scanner, an optical sensor, a mechanical pressure sensor, or a sensor that detects that a container has been attached, for example, using a movable pin.

[0049] According to one possible embodiment of the present invention, the controller is designed to determine a feedforward control value and / or starting value of the control and / or an average value of the permissible control range and / or a target value of the conductivity and / or predefined conductivity ranges based on the specifications of a prescription and / or on data relating to the component used, which can be entered into the controller. In particular, the data can be part of a prescription, which is entered into the dialysis machine, for example, via a patient card.

[0050] According to a first possible embodiment of the present invention, the control system is designed such that the first and / or second pump is controlled during patient treatment using the feedback of the measured conductivity to regulate the pump. In particular, in this case, the control preferably takes place within a permissible control range, as described above for the first aspect.

[0051] According to a further possible embodiment of the present invention, the control system is designed such that the conductivity control of the first and / or second pump only occurs during a phase in which the patient is not being treated. This ensures that the patient cannot be endangered by the control. This patient protection measure can be used alternatively or in addition to specifying a permissible control range, as described above.

[0052] Such a phase in which the patient is not treated can be a phase in which the patient is not connected to the device, in particular his vascular system is not connected to a tube system inserted in the device and / or in which the dialysis solution is not passed through the dialyzer, in particular is passed to the dialyzer via a bypass line and / or a phase in which a blood pump of the device is stopped and / or a phase in which an arterial clamp and / or a venous clamp, with which an arterial branch or a venous branch of the tube system is blocked, is or are closed.Such a phase may in particular be a test phase and / or a priming phase before treatment and / or a phase in which one or more of the concentrate sources is or are replaced, for example because a canister has become empty, and / or a phase in which a pressure maintenance test is carried out in which the dialysis solution is passed via the bypass line.

[0053] According to a possible embodiment of the present invention, the control is designed such that the conductivity control of the first and / or second pump takes place only before a treatment of the patient and / or in a phase in which the dialysis solution is passed past the dialyzer through a bypass.

[0054] According to a possible embodiment of the present invention, the control is designed such that the first and / or second pump is volumetrically controlled during the treatment of the patient without feedback of the measured conductivity for controlling the pump.

[0055] According to one possible embodiment of the present invention, the control system is designed such that the measured value of the first conductivity sensor is used only by the protection system during the treatment. The first conductivity sensor therefore serves only for monitoring by the protection system during this phase.

[0056] According to a possible embodiment of the present invention, the control is designed such that the volumetric control of the first and / or second pump during the treatment is carried out on the basis of operating parameters determined during the control.

[0057] According to a possible embodiment of the present invention, the control is designed such that the first component, in particular the bicarbonate concentrate, is added in a conductivity-controlled manner during the treatment and / or the second component, in particular the acid and / or sodium concentrate, is added in a volumetrically controlled manner during the treatment.

[0058] This aspect of the different control of the first and second pumps is also the subject of the present invention, independent of the first and second aspects described above. In a third, independent aspect, the present invention therefore comprises a dialysis machine with a mixing system for producing a dialysis solution by admixing at least a first and a second component to a liquid supplied to the dialysis machine, in particular water, comprising: a first pump for conveying the first component, in particular an acid and / or sodium concentrate, a second pump for conveying the second component, in particular a bicarbonate concentrate, and a controller for controlling the first and second pumps.The third aspect is characterized in that the second component, in particular the bicarbonate concentrate, is added during the treatment in a conductivity-controlled manner and / or the first component, in particular the acid and / or sodium concentrate, is added during the treatment in a volumetrically controlled manner.

[0059] All features described above with regard to the first and second aspects also form the third aspect in an identical manner in possible embodiments of the present invention.

[0060] In particular, the dialysis machine may comprise a second conductivity sensor which measures the conductivity of a mixture which comprises only the second component but not the first component.

[0061] Furthermore, the dialysis machine may comprise a first conductivity sensor which measures the conductivity of a mixture comprising the first and the second component, and in particular the conductivity of the finished dialysis solution.

[0062] Furthermore, the controller can be designed and, in particular, control the first and second pumps as described above with regard to the first and / or second aspect. However, the first conductivity sensor does not have to be part of the protection system.

[0063] Further preferred embodiments of the independent aspects described so far are described below. According to one possible embodiment of the present invention, the dialysis machine comprises a dialysate circuit to which a dialyzer can be coupled. The first conductivity sensor, whose measurement signal is preferably used to control the first and / or second pump, is arranged upstream of the dialyzer in the dialysate circuit. The first conductivity sensor can be arranged within a balancing circuit, in particular downstream of a balancing chamber system or upstream of the balancing circuit.

[0064] According to a possible embodiment of the present invention, only a single conductivity sensor, in particular the first conductivity sensor, is provided in a section of the dialysate circuit between the addition point of a last component, in particular the first component, and the dialyzer.

[0065] According to a possible embodiment of the present invention, the dialysis machine further comprises at least one third conductivity sensor, which is arranged downstream of the dialyzer in the dialysate circuit.

[0066] According to one possible embodiment of the present invention, the controller is designed to check the functionality of the first conductivity sensor located upstream of the dialyzer in a test mode using the third conductivity sensor located downstream of the dialyzer. This can increase patient safety.

[0067] This aspect of the test is also the subject of the present invention, independent of the aspects described above.

[0068] The present invention therefore comprises, in a fourth independent aspect, a dialysis machine with a mixing system for producing a dialysis solution by admixing at least a first and / or a second component to a liquid supplied to the dialysis machine, in particular water, comprising: a dialysate circuit to which a dialyzer can be coupled, a first pump for conveying the first component, in particular an acid and / or sodium concentrate, and / or a second pump for conveying the second component, in particular a bicarbonate concentrate, a controller for controlling the first and / or the second pump, a first conductivity sensor which is arranged upstream of the dialyzer in the dialysate circuit, a third conductivity sensor which is arranged downstream of the dialyzer in the dialysate circuit.The fourth aspect is characterized in that the controller is designed to check the functionality of the first conductivity sensor arranged upstream of the dialyzer in a test mode by means of the third conductivity sensor arranged downstream of the dialyzer.

[0069] All features which have been described above with regard to the further aspects also form the fourth aspect in an identical manner in possible embodiments of the present invention.

[0070] In particular, the dialysis machine may comprise a second conductivity sensor which measures the conductivity of a mixture which comprises only the second component but not the first component.

[0071] In particular, the first conductivity sensor can be arranged to measure the conductivity of a mixture comprising the first and second components, and in particular the conductivity of the dialysis solution. Furthermore, the controller can be designed to regulate the first and / or second pump by means of a control loop by feeding back the measured conductivity as a control variable.

[0072] The control system can also be designed in other ways, and in particular, control the first and second pumps as described above with regard to the other aspects. However, the first conductivity sensor does not have to be part of the protection system.

[0073] Further preferred embodiments of the independent aspects described so far are described below. According to one possible embodiment of the present invention, the controller is designed to perform the test of the conductivity sensor arranged upstream of the dialyzer using the third conductivity sensor arranged downstream of the dialyzer before treatment, in particular while the dialyzer is not yet connected to the dialysis solution lines and the dialysis solution lines are connected to each other by a short-circuit part and / or while the patient is not yet connected to the dialyzer.

[0074] According to a possible embodiment of the present invention, the control system is designed to carry out the testing of the conductivity sensor arranged upstream of the dialyzer by means of the third conductivity sensor arranged downstream of the dialyzer during a treatment interruption in which the dialysis solution is passed past the dialyzer via a bypass line.

[0075] According to a possible embodiment of the present invention, the control is designed such that it carries out the testing of the first conductivity sensor arranged upstream of the dialyzer by means of the third conductivity sensor arranged downstream of the dialyzer during a treatment interruption after a change of a container containing the first or second component, in which the dialysis solution is passed past the dialyzer via a bypass line.

[0076] According to one possible embodiment of the present invention, the controller is designed to switch to test mode when the conductivity measured by the first conductivity sensor leaves a predetermined range and / or to switch to test mode regularly. In particular, the controller is designed to control valves on the dialysate circuit in test mode so that the dialysis solution is bypassed by the dialyzer via a bypass line.

[0077] According to a possible embodiment of the present invention, the control is designed such that it also carries out the control in a predetermined control range or in addition to a control on the basis of an input or specification by the user that a certain amount of sodium should be withdrawn from the patient and / or that a concentration of sodium in the blood should not change during the treatment or should change according to the specification.

[0078] Alternatively, the control may be designed such that the predefined control range is changed during the treatment based on an input or specification by the user that a certain amount of sodium is to be withdrawn from the patient and / or that a concentration of sodium in the blood is to remain unchanged or is to change according to the specification during the treatment.

[0079] According to one possible embodiment of the present invention, the controller is designed such that it determines a value describing the treatment, in particular a value describing the progress of blood purification, on the basis of the conductivity measured by the third conductivity sensor during the treatment. The third conductivity sensor therefore preferably also performs several functions. The value describing the treatment can be a clearance measurement by means of which the extent to which the patient's blood has been purified can be determined. For this determination, for example, a conductivity bolus or a conductivity level can be generated during dialysis solution preparation, and the value can be determined based on the change in the pulse or level after passing through the dialyzer. Such a determination is described, for example, in patent documents US7674236B2 and US6702774A.

[0080] According to a possible embodiment of the present invention, the controller is designed to determine or adapt a target conductivity and / or a starting value of the control and / or an average value of the permissible control range and / or a permissible conductivity range on the basis of the value describing the treatment.

[0081] According to a possible embodiment of the present invention, the control is designed such that the conductivity of the mixture comprising the second component measured by the third conductivity sensor, and in particular the conductivity of the dialysis solution measured by the third conductivity sensor, is included in the control of the first pump.

[0082] According to a possible embodiment of the present invention, the controller is designed to adjust the dosage of the first component until the conductivity measured by the first conductivity sensor corresponds to a target conductivity.

[0083] According to one possible embodiment of the present invention, the protection system issues an alarm signal and / or places the dialysis machine in a safe state. The controller can initiate this if the conductivity measured by the first conductivity sensor leaves a permissible conductivity range. The controller can be designed such that the alarm signal and / or the placing of the dialysis machine in a safe state occurs immediately upon leaving the permissible conductivity range, or when the permissible conductivity range is left for a predetermined time, or when a predetermined control range is taken into account.

[0084] As already described above, in one possible embodiment of the present invention, the mixing system is designed to add an acid and / or sodium concentrate as a first component to a liquid supplied to the dialysis machine and to add a bicarbonate concentrate as a second component in order to produce the dialysis solution.

[0085] According to an alternative possible embodiment of the present invention, the mixing system is designed to add a sodium concentrate as the only component added by the mixing system to a first dialysis solution supplied to the dialysis machine in order to set a desired sodium concentration.

[0086] According to a further possible embodiment of the present invention, the mixing system is designed to add a sodium concentrate as a further component to a first dialysis solution produced by the mixing system from a bicarbonate concentrate and an acid concentrate in order to set a desired sodium concentration, wherein the addition of the sodium concentrate is preferably carried out by the first pump.

[0087] According to one possible embodiment of the present invention, the control system of the dialysis machine according to the invention is programmed to have the functions and functionalities described above and below, particularly with regard to the exemplary embodiment, and in particular to carry out the corresponding controls. In particular, the control system is automatic.

[0088] According to one possible embodiment of the present invention, the controller comprises a microprocessor and a non-volatile memory on which a computer program with instructions is stored. When executed on the microprocessor, these instructions implement the above-described functions and functionalities on the dialysis machine. For this purpose, the controller is in signal and control communication with the sensors and actuators of the dialysis machine, in particular the conductivity sensor(s) and pump(s).

[0089] The conductivity sensors can in particular be or have conductivity measuring cells.

[0090] The dialysis machine of the present invention can, in particular, be a hemodialysis machine. This machine can, in particular, be designed to perform hemodialysis, hemofiltration, and / or hemodiafiltration. Particularly when hemofiltration or hemodiafiltration is performed, the described control system can be used to regulate the composition of a dialysis solution that is fed directly into the blood-conducting tubing system, i.e., does not exchange with the blood via the dialyzer.

[0091] The present invention further comprises a method for producing a dialysis solution by means of a dialysis machine as described above, wherein the conductivity-controlled control of the first pump and / or the adjustment of the composition of the dialysis solution takes place, at least according to one embodiment, only before the start of treatment and / or only during an interruption of the patient's treatment. In an alternative embodiment, the conductivity-controlled control of the first pump can take place only or additionally during the treatment. The method and in particular the control of the pumps is preferably carried out within the scope of the method according to the invention in the same way as has already been described above with regard to the dialysis machines according to the invention.

[0092] The present invention will now be described in more detail with reference to a drawing and exemplary embodiments.

[0093] It shows:

[0094] Fig. 1 is a schematic diagram of a dialysate circuit in an embodiment of a dialysis machine according to the invention;

[0095] Fig. 2 a description of a first embodiment of the control;

[0096] Fig. 3 a description of further embodiments of the control;

[0097] Fig. 4 shows a schematic embodiment of a control system comprising a feedforward control and a closed-loop control; and

[0098] Fig. 5 a description of embodiments of the controls during the course of treatment and an embodiment of the control method.

[0099] Fig. 1 shows a dialysate circuit of an embodiment of a dialysis machine 10 according to the invention in a simplified schematic diagram, in which only the components relevant to the explanation of the present invention are shown. "Relevant" here does not mean "necessary."

[0100] The dialysate circuit comprises an inlet 11 for the fluid supplied to the mixing system, with which the components are mixed, in particular ultrapure water. It also comprises an outlet 12, through which, for example, used dialysis solution is discharged. The mixing system comprises a main line 14, through which the pump P4 pumps the fluid, in particular the water, toward the connection 18 for the dialyzer.

[0101] Downstream of the pump 14, lines open into this main line 14, via which the pumps P1 and P2 add the first and second components, respectively, to the liquid flowing in the main line.

[0102] The second component in the exemplary embodiment is a bicarbonate concentrate. In one possible embodiment, shown schematically in Fig. 1, this can be produced in the dialysis machine from a dry substrate. For example, the dry substrate is provided in a bag 30, into which water is introduced via line 13. This water partially dissolves the dry substrate and forms a saturated solution, which is pumped by pump P2 to the main line 14.

[0103] Alternatively or additionally, as indicated in Fig. 1 by the supply line 20 to the pump P2, the bicarbonate concentrate can be provided as a ready-made solution, for example via a canister.

[0104] The first component in this example is an acid and sodium concentrate. This is used in one possible configuration, which is shown in Fig.

[0105] 1, is provided as a ready-made solution in a container 40, for example a canister or bag, and pumped by the pump P1 to the main line 14. The acid and sodium concentrate may also contain one or more other components such as chloride ions, electrolytes such as calcium and / or magnesium ions, and glucose.

[0106] In the main line 14, downstream of the point where the pump P1 supplies the first component, a first conductivity sensor CD1 is provided, which measures the conductivity of the ready-mixed dialysis solution. A ready-mixed dialysis solution is characterized in that no further components are added downstream of the conductivity sensor CD1 in the direction of a dialyzer 50 before the dialysis solution is supplied to the dialyzer 50.

[0107] Furthermore, a second conductivity sensor CD2 is provided downstream of pump P2 in the feed line for the second component or, as shown in Fig. 1, in the main line 14 upstream of the point at which pump P1 feeds the first component and downstream of the point at which pump P2 feeds the second component. This second conductivity sensor CD2 therefore measures the conductivity of the second component or the conductivity of a mixture containing the liquid with the second component but not the first component. The conductivity sensor CD2 is used additionally because the concentration of the bicarbonate concentrate produced in the device depends on the dissolution behavior, temperature, etc., so that a delivery rate of pump P2 cannot be specified as a fixed value; instead, the concentration is determined via the conductivity sensor CD2 to control pump P2.

[0108] Furthermore, another conductivity sensor CD4 is provided in the main line 14, upstream of the point where pump P1 supplies the first component and downstream of the point where pump P2 supplies the second component. This conductivity sensor is assigned to the protection system. The conductivity sensor CD4 measures the conductivity of the mixture passing through it, and if the conductivity deviates from a setpoint or setpoint range, the control system interrupts the treatment.

[0109] The main line 14 has a connection 18 to which an inlet for the dialysis solution of the dialyzer 50 can be connected. An outlet of the dialysis solution side of the dialyzer 50 is connected to a connection 19 of a return line 23, via which the used dialysis solution is discharged to the drain 12. A blood circuit 55, by means of which the blood is conveyed from the patient to the dialyzer 50 and from the dialyzer 50 back to the patient, is shown only schematically in Fig. 1 and is of conventional design. It comprises an arterial line through which the blood is supplied to the dialyzer 50 and a venous line through which the blood is conveyed away from the dialyzer and to the patient. A blood pump, with which the blood can be pumped, is arranged in or on the arterial line.

[0110] Instead of connecting the dialyzer 50, the dialyzer connections 18 and 19 can be connected to each other via a short-circuit piece 17. This connection can be established, in particular, during a preparation phase and / or a post-treatment phase, in which, for example, components of the dialysate circuit are tested and / or the dialysate circuit is primed and / or the dialysate circuit is cleaned. Furthermore, a bypass line 16 is provided, through which the dialysis solution flow can be bypassed by switching appropriate valves during operation.

[0111] Furthermore, Fig. 1 schematically shows a balancing system 15 which balances the liquid pumped to the dialyzer and the liquid flowing out from the dialyzer. The balancing system can be a volumetric balancing system, for example one or more balancing chambers, each with a movable membrane, or rigid cylindrical chambers with a rigid, movable separating element, or a balancing system in which the volume of the inflowing and outflowing liquid can be determined based on flow measurement. Such systems have long been known from the prior art. However, the application of the present invention is not limited to such a balancing system, but can be applied to orbe used in devices with a balancing system in which the balancing is carried out by means of two flow sensors in which the flow to the dialyzer and the flow from the dialyzer are measured and the volume balance is determined from the difference between the flows.

[0112] In the exemplary embodiment, the conductivity sensor CD1 is arranged on the side of the balancing system 15 facing the dialyzer 50. In another embodiment, the conductivity sensor CD1 is arranged upstream of the balancing system 15. In balancing systems that function via flow sensors, the terms "upstream," "downstream," or "facing" refer to the position of the flow sensors. The dialysis machine 10 has a controller 21 that controls the pumps and valves of the dialysate circuit. Furthermore, a protection system 22 is provided that monitors the operation of the dialysis machine and in particular of the mixing system. The protection system 22 accesses one or more sensors and monitors their measured values ​​to determine whether they are within a permissible range, in particular a permissible conductivity range.In particular, the protection system 22 issues an alarm signal and / or puts the dialysis machine 10 into a safe state if the values ​​monitored by the protection system 22 leave the permissible range, although, as explained above, this does not have to happen immediately upon leaving this range. The controller 21 and the protection system 22 are preferably implemented via separate microcontrollers. The controller 21 and the protection system 22 can also be implemented on the same microcontroller. The controller 21 and the protection system 22 can be separated from one another by means of control and protection system software such that the control software cannot intervene in the functionality of the protection system or can only intervene to a predetermined extent. In other words, even if in Fig.1 the controller 21 and the protection system 22 are shown sketched as separate units, the controller 21 and the protection system can be designed as a controller or can be understood as a controller of the dialysis machine 10.

[0113] According to one aspect of the present invention, the conductivity sensor CD1 is part of the protection system 22 and is used by it to monitor the conductivity of the finished dialysis solution. If this conductivity leaves a permissible range, optionally for a predetermined time, the protection system 22 issues an alarm signal and / or puts the dialysis machine into a safe state, for example, by stopping the flow of dialysis solution to the dialyzer and / or bypassing the dialysis solution past the dialyzer via the bypass 17. According to a first aspect, the addition of the first component is conducted-controlled, with the controller 21 using the conductivity sensor CD1 for the control of the first pump P1, the conductivity sensor CD1 being part of the protection system 22.

[0114] Furthermore, the addition of the second component can also be controlled by conductivity. A separate conductivity sensor CD2, which is not part of the protection system 22, is used to control the pump P2 for the second component. The additional conductivity sensor CD4 is used by the protection system 22 to monitor the conductivity of the mixture of the liquid and the second component.

[0115] According to a further aspect of the present invention, the control of the first pump P1 is designed such that it may only change the flow rate of the pump P1 or the conductivity within a predetermined permissible control range (e.g., only within a window that would correspond to + / -5% of the target conductivity). Further details are described below, including with reference to Figs. 2 and 3.

[0116] The controller 21 can combine volume control with conductivity control, as explained in more detail below with reference to Fig. 4. To do this, the controller 21 can first adjust the delivery rate of the pump P1 based on the predetermined composition of the dialysis solution and taking into account the concentrate presented in the container 40. Since there is no feedback of a conductivity value in a control loop, this can be understood as volume control or as a feedforward control in the form of volume control. In addition to this volume-controlled control of the pump P1, the conductivity can be determined using the conductivity sensor CD1. If the conductivity deviates from an expected value, in this case equivalent to a setpoint or target value, the delivery rate of the pump P1 can be readjusted within the predetermined permissible control range and thus set in a conductivity-controlled manner.The volume-controlled control can be a first control mechanism, for example in the form of a coarse control or coarse adjustment or pre-control, and the conductivity-controlled control can be a second control mechanism following the first control mechanism, in particular a control mechanism, for example in the form of a fine control.

[0117] This aspect is optionally used in combination with the first aspect. It can also be used if the first conductivity sensor CD1 is not part of the protection system 22.

[0118] Various further options as to how the control can be carried out, and which are also the subject of the present invention, are described below:

[0119] The conductivity sensor CD1 measures the conductivity of the ready-mixed dialysis solution and uses the measured value from the conductivity sensor CD2 for the alkaline concentrate or the mixture of water and alkaline concentrate to determine and control the proportion of acid concentrate. Unlike successive control (see below), the acid component can be adjusted in a single step.

[0120] The dosages of the first and second components, i.e., the acid and bicarbonate, are determined by the sodium and bicarbonate prescription and the concentrate types used, particularly the acid content of the acid concentrate (for neutralization with bicarbonate). Typically, approximately 80% of the conductivity comes from the acid concentrate. The pump volume for the first pump P1 for the acid concentrate is determined by the control system from the prescription and can be adjusted, for example, by a maximum of + / - 5%, as described above.

[0121] The concentration of the bicarbonate concentrate can fluctuate significantly, and the flow rate of the second pump P2 must therefore be continuously adjusted, so that the delivered bicarbonate concentrate volume can fluctuate significantly. Overall, both concentrate portions are refilled with water in each balancing chamber to ensure that the full balancing chamber volume is achieved.

[0122] As an alternative to the procedure described above, the pump P2, in particular in the form of a bicarbonate pump, can be stopped during this initial control of the pump 1, in particular in the form of an acid concentrate pump, although this has the disadvantage that more time is required and more material is needed for the respective rinsing out of the previously present liquids.

[0123] Alternatively, pump P1 can be controlled so that the target conductivity value for the dialysis solution is reached, particularly gradually. This can be achieved, for example, in the form of a P-controller that adjusts the dosage of the acidic component until the conductivity measured by the first conductivity sensor CD1 corresponds to the expected conductivity. In this case, the deviation in the bicarbonate mixture should not exceed a maximum value. This method can be combined with the volume control described above as conductivity control.

[0124] If a pump P1 is mentioned in the description, this is synonymous with a first pump P1. If a pump P2 is mentioned in the description, this is synonymous with a second pump P2. If a conductivity sensor CD1 is mentioned in the description, this is synonymous with a first conductivity sensor CD1. The same applies to the conductivity sensors CD2 to CD4 and other numbered components of the dialysis machine.

[0125] Regardless of the exact type of control, the setpoint is preferably a predetermined value resulting from the user input for the desired dialysis composition or from a dialysate composition determined by the device based on a user input for the desired amount of sodium to be removed during dialysis treatment. One effect of specifying a permissible control range can be that if the user inadvertently adds the wrong concentrate, i.e. a concentrate with a composition that deviates from the composition specified by the user or a concentrate selected by the user in the user interface, the control is not sufficient to restore the conductivity to the correct level. Instead, an alarm is issued due to the deviation and / or the device is switched to a safe state.

[0126] This results in increased safety, as the conductivity sensor cannot detect the composition (individual electrolytes), but only the overall conductivity. With an unlimited control range, the target conductivity might be achieved by changing the admixture of the wrong concentrate, but the overall composition of the dialysis solution would still be incorrect.

[0127] A second permissible control range can be specified for the second pump P2 of the second component, i.e., the alkaline concentrate. The following specifications can exist for this control range: The dialysis machine can be configured to produce the alkaline concentrate using a dry base concentrate (BiBag) in the machine in the form of a saturated solution, or to aspirate the alkaline concentrate from a canister (e.g., via a suction rod, shown schematically in Fig. 1 as number 20), or the alkaline concentrate can be supplied directly to the machine from a central concentrate supply (not shown).

[0128] Which method is used during a treatment can either be specified by user input, or the device can detect it automatically. For example, the control system can detect that the suction rod 20 for suction from the canister is in an internal parked position within the device and therefore no canister is being used, and / or the device can detect that the dry concentrate has been added to the container 20 and conclude from this that the dry concentrate should be used, and / or the device can detect whether a central concentrate supply is connected or not. The control range for suction from the canister and / or the central concentrate supply can be smaller than for the dry concentrate, or the control range for the dry concentrate may not be restricted at all.The background is that one does not have to assume that the wrong dry concentrate has been attached (it is always bicarbonate), while a canister with the wrong concentrate composition could well have been attached.

[0129] Not restricting or using a wider control range for the dry concentrate can have the effect of generally generating fewer alarms and / or allowing the dry concentrate to be used more completely, since even if it is no longer a saturated solution, it can still be used by the bicarbonate pump adding more bicarbonate concentrate.

[0130] Further embodiments are described below:

[0131] Control via the conductivity sensor CD1 of pump P1 issues an alarm if a deviation beyond the permissible conductivity range is detected and / or the permissible conductivity range cannot be reached using the permissible control range. As explained above, this can be applied analogously for a predefined permissible control range for the flow rate of pump P1.

[0132] The control can check the conductivity sensor CD1 for controlling the pump P1 using a third conductivity sensor CD3 before treatment. Before treatment, the conductivity values ​​measured by the conductivity sensors CD1 and CD3 must match, since no exchange of electrolytes with the patient's blood takes place when the dialysis solution or, at this time, the priming fluid is passed through the dialyzer. The test can be performed before connection to the dialyzer, so that the dialysis solution / priming fluid is passed via the short-circuit path 17 or the bypass path 16. Alternatively or additionally, the dialysate circuit can be switched to a bypass of the dialyzer (for example, via the bypass path 16) during treatment, i.e. the dialysis solution is not passed through the dialyzer 50, but around it, so that the blood has no influence on the comparison measurement.For example, the test of conductivity sensor CD1 can be performed using conductivity sensor CD3 when the patient is connected to the dialysis machine. The reference conductivity sensor CD3 can be an additional conductivity sensor (already present), which is used, for example, for OCM measurements (online clearance measurement) and / or to determine changes in concentrations as they pass through the dialyzer for sodium balancing during treatment and / or to determine the absence of disinfectant. The conductivity sensor CD3 can be arranged on the dialysate drain line 23. For this calibration, it may be necessary to first flush out the fluid in the drain line 23. For this purpose, the control system can be programmed to pump a specified volume through the dialysate circuit.

[0133] When controlling pump P1 to the target conductivity and / or within the permissible conductivity range, the controller can use the measured values ​​of the first conductivity sensor CD1 and the third conductivity sensor CD3. Alternatively, only the conductivity sensor CD1 can be used, or the third conductivity sensor CD3 can be left unused.

[0134] To determine the target conductivity, the control system can use a combination of the conductivity sensors CD1 and CD3, for example for sodium balancing, where CD1 and CD3 are used to determine how much sodium has been transferred into or out of the blood, this value is compared with a target value for the sodium transfer and from this a target value for the conductivity and / or acid concentrate admixture is determined.

[0135] The CD1 test can be repeated according to a predefined program, e.g., at regular intervals or during specific events such as pressure maintenance tests, during which treatment is interrupted. CD1 can be tested when a conductivity drift has been detected by the control or protection system. This can be detected when a predefined limit is exceeded or when the conductivity value reaches a value outside the control range. In particular, the control system can be configured to detect the conductivity drift based on a continuous change in the conductivity value.

[0136] The test of CD1 can be initiated manually by the user.

[0137] The contribution of water to conductivity can be taken into account as follows:

[0138] The contribution of water is neglected because it is very small.

[0139] A measurement is taken at the beginning of operation, when only water is in the system, with one of the conductivity sensors, e.g. CD2, CD4 or CD1 along line 14. The conductivity of the water is taken into account by the control system as a fixed value when preparing the dialysis solution.

[0140] The conductivity sensor CD2, which controls the bicarbonate pump P2, or the conductivity sensor CD4 of the protection system 22 can also be used as an empty detector for the dry concentrate container 30. If a target conductivity can no longer be achieved via a control system, the control system indicates that there is no or insufficient bicarbonate in the container 30.

[0141] This procedure can be used to detect that something is wrong with the supply from container 30, especially at a time when sufficient bicarbonate is still present. For example, channels may have formed in the salt, leading to insufficient dissolution, thus resulting in a saturated solution, or there may be a problem with the connection to container 30. The protection system can detect this in advance. Furthermore, in one possible embodiment, a mixing chamber can be provided upstream of the conductivity sensor CD2. This improves the mixing behavior and (optionally) allows for venting.

[0142] Furthermore, in one possible embodiment, a mixing chamber can be provided upstream of the conductivity sensor CD1. This improves the mixing behavior and, optionally, allows for venting of the dialysis solution.

[0143] According to a further embodiment of the present invention, a two-stage process is used for admixing the first component, in particular the acid concentrate. In a first stage (when no patient is being treated), the pump P1 is initially regulated based on the conductivity sensor CD1 in the dialysate circuit so that the desired conductivity value is achieved (conductivity-controlled). In a second phase, in particular during treatment, the pump P1 is operated with the corresponding operating parameters determined in the first phase, and the same conductivity sensor CD1 is used only for the protection system 22, i.e., if deviations exceed the set limit values, the treatment is interrupted / terminated (volume-controlled).

[0144] In another embodiment, a so-called 3-mix system is operated accordingly. Here, the dialysis solution is prepared using a mixture of three components: base, acid, and the third component can be NaCl, for example. Since the physiologically relevant parameter for thirst / hypotension is the sodium content, at least one operating mode of the control system provides for the adjustment of the sodium content to be carried out exclusively via this component. Here, the first component can be, in particular, the sodium chloride solution or the acid solution.

[0145] In a further embodiment of a so-called 3-mix system, acid concentrate and bicarbonate concentrate are dosed as fixed volumes (i.e. via unregulated pumps) in such a way that, for example, a fixed bicarbonate content is achieved. The bicarbonate content can be, for example, 32 mmol / L. The precise adjustment of the sodium concentration is then carried out using only one adjustable pump P1 for the third component. This embodiment has in common with the other described embodiments that at least one pump is controlled via a conductivity sensor which is also used as a protection system and / or the control may only take place within a predetermined range. This embodiment is simpler in that there is only one controlled pump.

[0146] Another embodiment, which uses a sodium component like the 3-Mix system, whereby the readjustment via the sensor CD1 only affects this component, can be implemented in a dialysis machine with a central dialysis solution supply:

[0147] The central dialysis solution supply delivers a base dialysis solution, for example a bicarbonate solution with a bicarbonate content of 32 mmol / L and a sodium content of 128 mmol / L. The dialysis machine then only contains the NaCl component for dosing in order to achieve the target value of the dialysis solution sodium set by the user. Any tolerances in the base dialysate can be compensated for using the mechanism described for the 2-component mixture. In this configuration, the dialysis machine therefore only has one regulated pump to increase the NaCl concentration in the dialysis solution by, for example, 0-20 mmol / L. This allows the control system to compensate for tolerances in the base mixture, for example. By dosing the NaCl component, the control system can initiate or initiate conductivity pulses and / or conductivity levels as used in OCM measurements and / or conductivity changes as used in a sodium management process.generate.

[0148] The dialysis machine 10 shown in Fig. 1 can be a dialysis machine for hemodiafiltration. For this purpose, a drain (not shown) can be provided on the main line 14 downstream of the sensor CD1, through which the dialysis solution can be directly supplied to the bloodstream 55. For a dialysis machine for hemofiltration, the connection 18 can lead not to the dialyzer, but to the bloodstream 55.

[0149] Unless already explained in the context of the functions and options according to the invention, it is pointed out again here that the control 22 of the dialysis machine according to the invention is designed and in particular programmed in such a way that it provides these functions and options and implements their implementation.

[0150] Embodiments of the control system are explained with reference to Figs. 2 and 3. It is described using the dialysis machine 10, but is not limited to the dialysis machine 10 shown in Fig. 1.

[0151] In the procedure shown in Fig. 2, the dialysis machine 10 uses the measurement of the conductivity L by means of the first conductivity sensor CD1 for the safety system, which monitors whether the measured conductivity value (actual value I) is within the alarm window A defined by the alarm window limit values ​​Ai or A2 and aborts the treatment if the actual value I leaves the alarm window A. Independently of this, the dialysis machine 10 continues to use the measurement of the conductivity L by means of the first conductivity sensor CD1 to control the pump P1. If the measured conductivity value (actual value I) deviates from the setpoint S, which can result from a prescription, the control system changes the pump's delivery rate within the permissible control range R in order to reach the setpoint. By limiting the control to the control range R, the delivery rate is prevented from deviating too far from a predetermined delivery rate.

[0152] In the variants shown in Fig. 3, dialysis machine 10 also uses the measurement of conductivity L by means of the first conductivity sensor CD1 for control. If the measured conductivity value (actual value I) deviates from a target value, for example a setpoint S, which can result from a prescription, or an alarm window limit value Ai or A2, the algorithm can calculate a change in the delivery rate of the first pump P1 and compare this delivery rate with a permissible control range R and / or alarm range A. Likewise, by knowing the composition of the concentrate pumped by the first pump P1, the algorithm can calculate the expected effect of the changed delivery rate on the composition and / or the conductivity of the dialysis solution and compare this with a control range R and / or alarm range A for these variables. The embodiments of the control have in common that a setpoint S is provided.This target value S results, for example, from the prescription, specified profiles for the composition of the dialysis solution or from specified algorithms such as sodium balancing, in which a specified amount of sodium is to be removed from or supplied to the patient during treatment. An alarm window A can be provided around this target value. If ranges are named that are arranged around a single value, these can be arranged symmetrically or asymmetrically around this value. For example, a range can deviate +-5% from this value, or from +2% to -7% from this value. A range can only extend in one direction, which means that the deviation in the other direction can be 0%.

[0153] In a first embodiment of the control system, the conductivity value is brought into the alarm window A. As long as the actual value I lies within the alarm window, the control system does not intervene by regulating the delivery rate of the first pump P1. No alarm is issued. If an actual value I2 is measured outside the alarm window A, the control system 22 or an algorithm of the control system 22 determines whether the alarm window A would be reached if the delivery rate of the first pump P1 were intervened within a predetermined control range R. If this is the case, the control system 22 changes the delivery rate of the first pump P1. If this is not the case, the control system 22 intervenes, for example by interrupting the treatment and / or blocking a subsequent treatment.In other words, if the regulation makes it possible to bring the composition into a predetermined range, in particular a range that is safe for the patient, it will be regulated accordingly, and if this is not possible, treatment will be prevented.

[0154] In a variant of the previous embodiment, the controller 22 or the algorithm does not initially calculate whether the control range R is large enough to reach the alarm range A, but instead intervenes in the control of the delivery rate of the first pump P1. Based on the resulting changes, for example the delivery rate or the measured conductivity, the controller 22 determines whether the value lies within the control range R and terminates the control if this is not the case. The controller 22 can be programmed not to intervene with control if the actual value I deviates by a specified distance from the setpoint S and / or an alarm limit Ai and / or A2. This can mean that in the event of significant deviations from the actual value I, the treatment can be immediately interrupted or blocked.The controller 22 can additionally or alternatively be programmed to terminate the control after a predetermined time if the alarm range A has not been reached within this time window. This can prevent the patient from being treated with a composition outside the alarm window A for too long. The controller 22 can additionally or alternatively be programmed to terminate the control if an unsuitable trend in the flow rate change or conductivity change occurs. This can prevent the patient from being treated with a composition outside the alarm window A and prevent the control from being suitable for bringing the patient into the alarm window A range.

[0155] In a second embodiment of the control system, the conductivity value is brought to a setpoint S. If the actual value I1 lies within the alarm window, the control system intervenes on the delivery rate of the first pump P1. No alarm is issued. If an actual value I2 is measured outside the alarm window, the control system does not intervene on the delivery rate of the first pump P1 and the treatment is interrupted. The alarm window A can correspond to the control range R, i.e. the controller 22 can carry out the control within the entire alarm window A. Alternatively, a control range R can be provided which is different from the alarm window A, so the control range R can be larger or smaller than the alarm window A and the control range R can only partially overlay the alarm window A.If the control range R includes an area outside the alarm window A, the controller 22 can be configured to allow control only for the areas of the control range R that lie within the alarm window A.

[0156] Such a limitation of the control range of permissible delivery rates can also be provided in the first embodiment. In further variants of the control embodiment, the controller 22 can control the actual value I to a value within the alarm window A, i.e., there is a target corridor within the alarm window A. This ensures that the value achieved by the control is not too close to the alarm window limits, thus reducing the frequency with which the control must intervene.

[0157] The variants and embodiments can be implemented individually or in any combination in the dialysis machine 10.

[0158] As shown in Fig. 4, the control of the first pump P1 can combine a volume-based pilot control 23 and a conductivity-based control 24. For this purpose, the controller can calculate a desired delivery rate V for the pump P1 on the basis of a specification 25, for example a prescription and the stored composition of the concentrate. From the desired delivery rate and a stored pump characteristic of the first pump P1, the controller then determines, in a further component not shown, a value of a control variable, for example a current strength of a drive of the pump P1, which is used to pilot control the pump P1. As a result, a specific amount of concentrate is pumped and a dialysis solution is generated.This dialysis solution displays an actual value I measured by the sensor CD1, which does not have to match the target value S, which is also determined based on a specification 25 and / or a prescription and the stored composition of the concentrate. This can be due, for example, to the fact that the pump P1 does not deliver exactly the assumed or stored volume and / or the concentrate does not have exactly the assumed or stored composition and / or other parameter values ​​that influence the actual value I do not correspond to the assumed or stored parameter values. Therefore, this volume-controlled feedforward control 23 of the pump can represent a rough adjustment. In addition to this rough adjustment, the controller can perform the conductivity-controlled control 24 described in the description and bring the conductivity value closer to or to the target value S.Therefore, this conductivity-controlled operation of the pump can represent a fine adjustment. The control loop can either adjust the desired flow rate V or directly adjust the control variable. Preferably, as described above, the control takes place only within the permissible control range R, i.e., for example, within a permissible control range around the value of the flow rate V or the control variable determined by the pilot control. Where reference is made elsewhere in this application to a permissible control range for the flow rate, this also includes a permissible range for the control variable itself.

[0159] Figure 5 illustrates embodiments in which phases the controller 22 can be configured or programmed to initiate the control according to the invention. This is described using the dialysis machine 10, but is not limited to the dialysis machine 10 shown in Figure 1.

[0160] The controller 22 can intervene before treatment to regulate the flow rate of the first pump P1, i.e., in an initial phase 100 in which no patient is fluidically connected to the dialysis machine. In this initial phase 100, the controller can regulate the flow rate such that the conductivity is at the setpoint S or within the target range or within the alarm limits A. In this case, the pump P1, in particular the acid pump, is regulated by means of the first conductivity sensor CD1.

[0161] In this initial phase 100, the first conductivity sensor CD1 can also be calibrated with the third conductivity sensor CD3 before the control process. This is possible because, before the treatment, the solution measured by the first conductivity sensor CD1 and the third conductivity sensor CD3 is the same solution or has the same composition.

[0162] If the calibration detects a malfunction of one of the sensors or if control to the setpoint fails, an alarm can be triggered. Alternatively or optionally, the controller can intervene during a treatment interruption to regulate the flow rate of the first pump, i.e., in an interruption phase 120, in which no dialysis solution is passed through the dialyzer 50 and / or supplied to the blood tubing set 55. In this phase, the controller 22 can intervene in the same way as in the initial phase 100.

[0163] Preferably, control is carried out only within the permissible control range, as described above.

[0164] During treatment, i.e. in a treatment phase 110, 130 in which a patient is connected and a dialysis solution is passed through the dialyzer 50 and / or is supplied to the blood tubing set 55, the controller 22 can actuate the first pump P1 in a volume-controlled manner according to a first variant. The conductivity measured by the first conductivity sensor CD1 is used only by the protection system 22 during this treatment phase 110, 130, but not for control. The value that was reached or set by the previous control in the initial phase 110 or the treatment interruption 120 can be used for the delivery rate of the first pump P1. The delivery rate can be changed if necessary based on other specifications, e.g. sodium balance and / or sodium profiles.

[0165] Alternatively or optionally, the controller can intervene during the treatment to regulate the delivery rate of the first pump P1 on the basis of the conductivity measured by the first conductivity sensor CD1, ie in a treatment phase 110, 130 in which a patient is connected and a dialysis solution is passed through the dialyzer 50 or is supplied to the blood tubing set 55.

[0166] In this phase 110, 130, the controller can intervene in the same way as in the initial phase 100. In this phase, the alarm limits and / or the control range can be different from the alarm limits and / or the control range in the initial phase 100 or the treatment interruption 120. In the treatment phase 110, 130, the controller 22 can be configured or programmed to intervene in the delivery rate of the first pump P1 based on other specifications, e.g., sodium balance and / or sodium profiles. This is preferably achieved by taking the other specifications into account during the pre-control.

Claims

Dialysis machine with a mixing system for producing a dialysis solution Claims 1. Dialysis machine with a mixing system for producing a dialysis solution by admixing at least a first and optionally a second component to a liquid supplied to the dialysis machine, in particular water, comprising: a first pump for conveying the first component, in particular an acid and / or sodium concentrate, and optionally a second pump for conveying the second component, in particular a bicarbonate concentrate, a controller for controlling the first and optionally the second pump, and a protection system for monitoring the dialysis solution, wherein the protection system comprises a first conductivity sensor which measures the conductivity of the dialysis solution, wherein the protection system causes the controller to interrupt an ongoing treatment if the conductivity measured by the first conductivity sensor deviates from a predetermined conductivity range, characterized in that the controller accesses the conductivity measured by the first conductivity sensor of the protection system and controls the first pump by means of a control loop by feeding back the measured conductivity as a control variable.

2. Dialysis machine according to claim 1, wherein the control of the first pump by the controller only takes place within a first predetermined permissible control range and / or only takes place when the conductivity measured by the first conductivity sensor effects a control within a first predetermined permissible control range and / or when a controlled variable can be brought into a first predetermined permissible control range by the control loop and / or when no ongoing treatment is taking place, wherein the first predetermined permissible control range in particular comprises the predetermined conductivity range and / or is in particular a predetermined permissible control range for permissible delivery rates.

3. Dialysis machine according to claim 1 or 2, wherein the dialysis machine comprises a second conductivity sensor which measures the conductivity of a mixture which comprises the second component and the liquid supplied to the dialysis machine, in particular water, but not the first component, wherein the second pump is conductivity-controlled by feedback of the conductivity measured by the second conductivity sensor, wherein the control is optionally designed such that the control of the second pump only takes place within a second predetermined permissible control range, in particular only within a second predetermined conductivity range and / or a second predetermined control range of permissible delivery rates.

4. Dialysis machine according to claim 2 or 3, wherein the first predetermined permissible control range and / or the second predetermined permissible control range is less than +- 20% of an average value of the control range, preferably less than +- 10%, preferably less than +- 5% and / or wherein the second control range pro- is significantly greater than the first control range and / or wherein the first and / or second control range is set such that it only allows control towards a setpoint value for the conductivity.

5. Dialysis machine according to one of claims 2 to 4, wherein differently sized permissible first and / or second control ranges are stored in the control system, which the control system uses depending on the currently used source of the component for controlling the first and / or second pump, in particular for controlling the second pump, wherein the currently used source of the component can preferably be entered via a user interface and / or is automatically detected by the control system.

6. Dialysis machine according to one of claims 2 to 5, wherein the controller comprises a volume-based pre-control of the first and / or second pump, which determines a desired delivery rate and / or control variable on the basis of the specifications of a prescription and / or on the basis of data on the component used and uses it to pre-control the first and / or second pump, wherein the controller readjusts the desired delivery rate and / or control variable within a permissible control range based on conductivity, and / or wherein the controller is designed such that it determines a start value of the control and / or an average value of the first permissible control range and / or a target value of the conductivity on the basis of the specifications of a prescription and / or on the basis of data on the component used, which can be transmitted to the controller.

7. Dialysis machine according to one of the preceding claims, wherein the control is designed such that the regulation of the first pump takes place on the basis of the measured conductivity in a phase, preferably only in a phase, in which the patient is not being treated, wherein the phase is a phase before treatment of the patient and / or a phase during which the dialysis solution is passed past the dialyzer through a bypass, wherein the first pump is volumetrically controlled during the treatment of the patient, preferably without feedback of the measured conductivity. is controlled, wherein the measured value of the first conductivity sensor is preferably only used by the protection system during the treatment and / or the volumetric control of the first pump during the treatment is preferably carried out on the basis of operating parameters determined during the control.

8. Dialysis machine according to one of the preceding claims, in particular according to claim 7, wherein the control is designed such that the second component, in particular the bicarbonate concentrate, is dosed during the treatment in a conductivity-controlled manner.

9. Dialysis machine according to one of the preceding claims, with a dialysate circuit to which a dialyzer can be coupled, wherein the first conductivity sensor, whose measurement signal is used to control the first pump, is arranged upstream of the dialyzer in the dialysate circuit, and / or only a single conductivity sensor, in particular the first conductivity sensor, is provided in a section of the dialysate circuit between the addition point of a last component, in particular the first component, and the dialyzer.

10. Dialysis machine according to claim 9, wherein the dialysis machine comprises at least one third conductivity sensor, which is arranged downstream of the dialyzer in the dialysate circuit, and wherein the control is designed to test the functionality of the first conductivity sensor in a test mode by means of the third conductivity sensor, wherein the control is optionally designed such that the control carries out the test before the treatment, in particular while the dialyzer is not yet connected to the dialysate lines and the dialysate lines are connected to each other by a short-circuit part and / or the dialysis solution bypasses the dialyzer via a bypass line and / or while the patient is not yet connected to the dialyzer, and / or that the control system carries out the test during a treatment interruption in which the dialysis solution is bypassed past the dialyzer via a bypass line, and / or that the control system switches to test mode when the conductivity measured by the first conductivity sensor leaves a predetermined range, and / or that the control system regularly switches to test mode.

11. Dialysis machine according to claim 9 or 10, wherein the controller is designed to determine a value describing the treatment, in particular a value describing the progress of the blood purification, on the basis of the conductivity measured by the third conductivity sensor during the treatment, wherein the controller is preferably designed to adapt a target conductivity and / or a starting value of the control and / or an average value of the permissible control range on the basis of the value describing the treatment.

12. Dialysis machine according to one of the preceding claims, wherein the conductivity of the mixture comprising the second component measured by the second conductivity sensor is included in the control of the first pump, and / or wherein the control adjusts the dosage of the first component until the conductivity measured by the first conductivity sensor corresponds to a desired conductivity.

13. Dialysis machine according to one of the preceding claims, wherein the protection system issues an alarm signal and / or puts the dialysis machine into a safe state when the conductivity measured by the first conductivity sensor leaves a permissible range, in particular the predetermined conductivity range.

14. Dialysis machine according to one of the preceding claims, wherein the first component is a sodium concentrate, and the control is arranged to set a desired sodium concentration in the dialysis solution, and wherein optionally the first component is the only component which is mixed with the liquid supplied to the dialysis machine in order to provide the dialysis solution, or wherein optionally the mixing system is designed to additionally produce the dialysis solution from the second component in the form of bicarbonate concentrate and a third component in the form of an acid concentrate.

15. A method for producing a dialysis solution by means of a dialysis machine according to one of the preceding claims, wherein the control of the first pump on the basis of the measured conductivity and / or the adjustment of the composition of the dialysis solution preferably takes place before the start of the treatment and / or during an interruption of the treatment of the patient, and wherein further preferably the treatment takes place by means of a volumetric control of the first pump and / or the dialysis solution or a dialysis solution derived therefrom.

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