Model-based mixing of dialysis liquid for a dialysis device

Abstract

The present invention relates to a method, a computing unit (R), and a mixing device (M) for calculating a set of result data (331) regarding the composition of a dialysis fluid (df) to be mixed with multiple components based on a calculation model (BM) for the conductivity of the dialysis fluid. The method comprises the following steps: - reading (51) a set of mixing ratio data (311) representing a mixing ratio of at least one component A, component B, and a third component; - detecting (52) component parameters, including a first substance concentration parameter, particularly representing the concentration of salts in component A, and a second substance concentration parameter, particularly representing the concentration of salts in component B; - calculating (53) the resulting set of result data (331) regarding the composition of the dialysis fluid, the result data set including a description of the substance concentrations in the dialysis fluid based on the calculation model (BM) and a description of the expected value of the conductivity of the dialysis fluid.

Description

Technical Field

[0001] This invention relates to a monitored and model-based mixture of dialysate for use in a dialysis apparatus. More particularly, this invention relates to a mixing device, a dialysis apparatus having such a mixing device, and a method for operating the mixing device. Background Technology

[0002] Dialysis equipment is a blood therapy device in which a patient's fluid is delivered via fluid tubing to a fluid therapy component, treated by the fluid therapy component, and returned to the patient via fluid tubing that can be divided into arterial and venous branches. Examples of such blood therapy devices are, in particular, hemodialysis devices. This type of blood therapy device is the subject of the applicant's DE 198 49 787 C1, the contents of which are hereby fully incorporated into the disclosure of this application.

[0003] Dialysis is a method of cleaning the blood in patients with acute or chronic renal failure. In principle, this is distinguished between methods that utilize an extracorporeal blood circuit, such as hemodialysis, hemofiltration, or hemodiafiltration, and peritoneal dialysis that does not utilize an extracorporeal blood circuit.

[0004] During hemodialysis, blood is guided through the blood chamber of the dialyzer in the extracorporeal blood circuit. This blood chamber is separated from the dialysate chamber via a semipermeable membrane. The dialysate chamber is filled with dialysate containing a specific concentration of blood electrolytes. Here, the concentration of blood electrolytes in the dialysate corresponds to the concentration of blood electrolytes in the blood of a healthy person.

[0005] During treatment, the patient's blood and dialysate typically pass in a countercurrent flow at a preset flow rate across a semipermeable membrane. Substances that need to be excreted in urine diffuse across the membrane from the blood chamber to the chamber used for dialysate, while electrolytes present in the blood and dialysate diffuse from the chamber with higher concentrations to the chamber with lower concentrations, respectively. If a pressure gradient is formed at the dialysis membrane from the blood side to the dialysate side, for example by a pump that extracts dialysate from the dialysate circuit downstream of a dialysis filter on the dialysate side, then water is transferred from the patient's blood through the dialysis membrane into the dialysate circuit. This process, also known as ultrafiltration, results in the desired dehydration of the patient's blood.

[0006] During hemofiltration, ultrafiltrate is extracted from the patient's blood by applying transmembrane pressure within the dialyzer, while the dialysate does not pass through the dialyzer membrane on the side opposite to the patient's blood. Additionally, a sterile and pyrogen-free replacement solution can be added to the patient's blood. Whether this replacement solution is added upstream or downstream of the dialyzer is referred to as pre-dilution or post-dilution. During hemofiltration, mass exchange occurs convectively.

[0007] Hemodialysis filtration combines hemodialysis and hemofiltration. It involves not only the exchange of substances through diffusion between the patient's blood and the dialysate via the dialyzer's semipermeable membrane, but also the filtration of plasma water contained in the blood through the pressure gradient at the dialyzer's membrane.

[0008] Hemodialysis, blood filtration, and hemodialysis filtration are typically performed using automated hemodialysis equipment, such as the hemodialysis equipment sold by the applicant.

[0009] Plasma separation is a blood therapy in which a patient's blood is separated into plasma and its particle components (cells). The separated plasma is cleaned or replaced with a replacement solution, and the cleaned plasma or replacement solution is returned to the patient.

[0010] In peritoneal dialysis, the patient's peritoneal cavity is filled with dialysate via a catheter inserted through the abdominal wall. This dialysate has a concentration gradient of blood substances such as electrolytes (e.g., sodium, calcium, and magnesium) relative to the body's own fluids. Toxic substances present in the body are transferred from blood vessels extending through the peritoneum, which acts as a membrane, into the peritoneal cavity. After several hours, the dialysate in the patient's peritoneal cavity, now mixed with the toxic substances removed from the body, is replaced. Through osmosis, water from the patient's blood is transferred through the peritoneum into the dialysate, thus dehydrating the patient.

[0011] Methods for peritoneal dialysis are typically performed using automated peritoneal dialysis equipment, such as the peritoneal dialysis equipment sold by the applicant.

[0012] Dialysis fluids used in dialysis equipment are typically prepared by mixing at least two dialysis concentrates with RO water (RO = reverse osmosis). To form the dialysis fluid, a tank for the RO water and containers for the different concentrates or components can be used. Concentrates can be provided in solid and / or liquid form.

[0013] In certain treatment types, such as "bicarbonate hemodialysis," two dialysis concentrates are typically used. Prior to dialysis, these concentrates are diluted in a defined amount with RO water and mixed to form what is known as the dialysate. The concentrates are an acidic concentrate (component A) and an alkaline concentrate (component B). The alkaline concentrate typically consists of a sodium bicarbonate solution of a defined concentration. The acidic concentrate contains all the remaining components necessary for dialysis treatment. This is especially true of electrolytes, namely sodium, potassium, calcium, and magnesium, and additionally of chlorides and acetates. The acidic concentrate may also include glucose.

[0014] In a first method for preparing dialysis fluid, mixing is carried out by means of a volume mixing method, wherein water and concentrate are mixed together at a specific preset volume ratio.

[0015] A second method for preparing dialysate is a conductivity adjustment method, wherein the ratio of the water component and the concentrate component is adjusted to set a certain conductivity in the prepared dialysate, the conductivity being caused by the electrolyte concentration or substance concentration in the prepared dialysate. This second conductivity adjustment method is intended to improve the present invention.

[0016] To ensure treatment safety, the composition of the dialysis fluid must be monitored. In particular, standard ISO EN DIN 60601-2-16 requires that dialysis equipment must monitor the composition of the dialysis fluid for sodium and bicarbonate. The protection system must identify any deviations from the pre-defined expected values ​​and protect the patient from danger.

[0017] In conductivity-regulated dialysis equipment, the conductivity of the pre-mixed dialysate is used as the measurement variable. A desired conductivity value with a preset expectation is calculated based on the electrolyte concentration in the dialysate. For this to be effective, the electrolyte concentration must be known.

[0018] Typically, in dialysis equipment, the concentrations of various electrolytes (Na, K, Ca, Mg, Cl, acetate, citrate, bicarbonate) and other components (such as glucose, possibly) are entered by the user in the service menu on the equipment's user interface, based on a preset formula (a mixture of RO water, A concentrate, and B concentrate).

[0019] However, some devices allow for changes or adjustments to the specified sodium carbonate and bicarbonate values. That is, if the user adjusts these values, the metered volumes of concentrate A and concentrate B change accordingly, thus altering the concentrations of all other electrolytes. To automatically calculate these concentrations, the machine requires additional concentration parameters: the acid concentration from concentrate A and the sodium concentration from concentrate B.

[0020] However, the latter two values ​​are not listed in the concentrate manufacturer's ingredient list. Currently, in existing technology, acid and salt concentrations are manually entered by the user. This requires highly specialized expertise to correctly determine the acid and salt concentrations. Further calculations are based on this manual input. Therefore, this approach is susceptible to error. Standard-trained service technicians cannot perform this operation.

[0021] In addition, the following error sources cannot be identified:

[0022] a) Incorrectly printed values ​​in the list of contents on the concentrate container, and

[0023] b) The description of the electrolyte concentrate involves a dilution ratio that differs from the corresponding formulation. Summary of the Invention

[0024] Therefore, based on systems known in the prior art for providing mixed dialysis fluids, the present invention aims to automate and improve the mixing of dialysis fluids while maintaining the feasibility of flexible changes in sodium and bicarbonate values. In particular, the composition of the dialysis fluid should be subject to automated monitoring. Furthermore, the mixing process should be optimized to make the overall treatment safer.

[0025] According to the present invention, the objective is achieved by the method, the computing unit, the mixing device, and the dialysis machine.

[0026] In the following description, the invention is described with reference to the intended solution according to the method. The features, advantages, or alternative embodiments mentioned herein are also applicable to other claimed subjects, and vice versa. In other words, embodiments for, for example, dialysis machines or devices can also be improved by incorporating the features described or claimed in conjunction with the method. Here, the corresponding functional features of the method are constituted by corresponding physical modules, particularly by electronic hardware modules or microprocessor modules, and vice versa.

[0027] The means proposed here to achieve the objectives described above involve two aspects:

[0028] 1. A first means (method) for calculating the ingredients (referred to herein as components) for dialysis fluid, enabling the correct mixing of the concentrate or component with the resulting or desired electrolyte concentration. For this purpose, a numerical calculation model based on simplified calculations is provided. Data from such calculations are provided as a set of resultant data, which approximately includes the formulation having a desired value of the conductivity of the resulting dialysis fluid.

[0029] 2. A second means (operational method) for checking whether the previously determined formula is also followed. Therefore, it is necessary to monitor whether the mixture results conform to the preset parameters of the previously determined formula. For this purpose, a sensor for measuring conductivity is provided, which compares the measured conductivity with the expected value calculated from the result data set. The second method is performed after the first method in time. Both methods solve the same problem, but in principle, they can be used independently of each other.

[0030] According to a first aspect, the present invention relates to a method for calculating a set of result data regarding the composition of a dialysis fluid (for use in a dialysis machine) to be composed of a mixture of multiple components (at least two), based on a calculation model for the conductivity of dialysis fluids, the method comprising the following steps:

[0031] - Read the mixing ratio data set, which represents the mixing ratio of at least one component A (e.g., A concentrate, acidic) and—optionally component B (e.g., B concentrate, alkaline, salt only)—and another (or second or third) component (RO water). Here, the component is typically a concentrate or another inclusion. If the mixing ratio data set is predefined, it can be automatically read from memory via an interface. Alternatively, the mixing ratio data set may also be user-defined and input by the user via a user interface. It is also possible to add other components or ingredients to the dialysis fluid.

[0032] - Component parameters are determined, including a first substance concentration parameter representing the concentration of a substance in component A and a second substance concentration parameter representing the concentration of a substance in component B. Component parameters relate to the concentration of each component or concentrate in its unmixed state. Component parameters, in particular, do not relate to the concentration in the dialysate to be mixed (mixed state). Component parameters provide a chemical description of the components in their unmixed state (unprocessed state, e.g., as a concentrate).

[0033] - A set of resultant data on the composition of the (to be generated) dialysate (particularly derived from the mixed ratio data set and the detected component parameters), including descriptions of the concentrations of substances (such as electrolyte concentrations) in the (to be generated) dialysate based on computational models and descriptions of the expected values ​​of the conductivity of the (to be generated) dialysate. The resultant data set relates to the mixing state of the dialysate.

[0034] In a preferred embodiment of the present invention, the method includes:

[0035] - Check whether the concentrations of the substances in the calculated result data set are within the predefined standard range, and if so, store the mixing ratio data set as a confirmed formulation for dialysis fluid.

[0036] The implementation method has the following advantages: it can only store confirmed recipes in the system, that is, recipes that meet the preset standard range that can be defined in advance.

[0037] Typically, concentrate A contains both salt and acid. Concentrate B contains only salt, i.e., no acid.

[0038] Different dialysis methods exist, differing only in the quantity and composition of the concentrates or components to be mixed. In current bicarbonate dialysis, three liquids are mixed: concentrate A, concentrate B, and RO water. In acetate dialysis, only two liquids are mixed: concentrate A and reverse osmosis water. The method described herein should also be used in acetate dialysis (mixing two components). In the 3MIX method, four components or liquids are mixed: concentrate A, concentrate B, a customized concentrate, and RO water. The recommendations based on the invention described herein are also used here.

[0039] In a preferred embodiment of the invention, the first substance concentration parameter and the second substance concentration parameter relate to the concentration of a specific substance (especially a salt) in the different components in the unmixed state. Alternatively, the acid concentration can also be detected for the selected component.

[0040] According to another preferred embodiment of the invention, upon successful verification, the read mixing ratio data set is used as the (confirmed) recipe, wherein an ID number or identification code is associated one-to-one with the recipe. This allows for highly efficient performance of further calculations.

[0041] According to another advantageous embodiment of the invention, the method additionally (after calculating the result data set) includes the following method steps:

[0042] - Displays the concentration of substances (produced in a mixed state), and / or

[0043] - If the concentration of the generated substance is not found to be within the standard range: issue a warning notice.

[0044] In another preferred embodiment of the invention, a method for monitoring a mixing device and the dialysis fluid mixed by means of the mixing device is used by measuring the current conductivity of the prepared dialysis fluid and comparing it with (especially from the formulation) a desired preset and / or with a calculated desired value of conductivity, so as to issue an error report in case of inconsistency.

[0045] Concentration of substances, especially salt concentration.

[0046] In another advantageous embodiment of the invention, the calculation model is based on salt strength, wherein salt strength is a measure of the sum of all molar concentrations for all salts, and wherein, in the calculation model, conductivity is associated with salt strength.

[0047] The computational model is used to predict the conductivity of the resulting dialysate, which is a solution containing various electrolytes. The calculated result set is obtained with sufficient accuracy for dialysis.

[0048] Therefore, in the calculation model, the molar conductivity of the electrolyte is always calculated in the same way, regardless of whether a mixture of multiple components exists. The molar conductivity of pure electrolytes can be read from pre-stored tables for different concentrations.

[0049] To calculate the result set of data, the solution of concentrate A must be calculated.

[0050] Concentrate A is achieved using the following coefficients:

[0051]

[0052] in:

[0053] V a This indicates the metered volume [mL] of concentrate A in the corresponding pump A.

[0054] V mix This indicates the total volume of dialysis fluid for each batch or mixing cycle [mL].

[0055] Enter the mixing ratio data set and the sum of all components of the mixture (e.g., in the 2MIX method: Concentrate A, Concentrate B, and RO water). After entering the mixing ratio data set, the concentration of each salt contained in the dialysis fluid is calculated computer-based and automatically.

[0056] The mixing ratio of the dialysis fluids for the solution of concentrate A can be expressed mathematically as follows:

[0057]

[0058] The concentration C of the dialysate can be derived from substance X in component or concentrate A through the following calculation. x :

[0059]

[0060] in:

[0061] C X This indicates the concentration of the dialysis fluid for substance X;

[0062] m x This indicates the weighed mass of substance X.

[0063] V a Indicates that the dissolved mass is m x The volume [L] of concentrate A;

[0064] M X Express the molar mass of substance X [g / mmol];

[0065] x mixThis represents the solubility coefficient of concentrate A.

[0066] If glucose should be added, the dialysate concentration C is calculated by deducing from concentrate A using the following method. C6H12O6 :

[0067]

[0068] in:

[0069] C C6H12O6 This indicates that glucose C6H is an optional component. 12 O6 concentration in the dialysis fluid [g / L],

[0070] m G Indicates the weighing mass of glucose

[0071] f G Indicates the correction factor

[0072] f G =1.0 represents the correction factor when weighing glucose hydrate.

[0073] f G =1.1 represents the correction factor when weighing glucose monohydrate.

[0074] The corresponding relationship applies to solutions of concentrate B. Therefore, in the above formula, only the components referring to component A are replaced by "B".

[0075] The computational model used to calculate the expected conductivity of the dialysate to be produced is based on the knowledge that if a substance dissolves in water, the chemical bonds between electrolytes break partially or completely. The electrolyte then dissociates into positively charged and negatively charged ions. Moving charge carriers carry the charge in the aqueous solution. Increasing the electrolyte concentration C generally increases the conductivity. The conductivity is defined as:

[0076]

[0077] in:

[0078] G=I / U represents conductivity [S=1 / Ω]: the relationship between current I and voltage drop.

[0079] l represents the spacing or length of the electron flow path [m].

[0080] A represents the cross-sectional area of ​​the current being conducted [m] 2 ]

[0081] K=l / A represents the battery constant of the LF sensor [1 / m].

[0082] Due to the reduced mobility of ions, the slope of conductivity (mathematically: the derivative) decreases as the concentration C increases. This can be experimentally demonstrated in the measured molar conductivity.

[0083] The computational model is based on the simplification that the molar conductivity of each electrolyte / salt is considered to be solely dependent on the total electrolyte concentration Q, and the expected conductivity of the dialysate is determined from this. The interdependencies between the individual components are not considered and are therefore not calculated in the model. Thus, the salt intensity Q can be calculated in the model as the sum of the molar concentrations of all salts. The unit is moles per liter. For an exemplary dialysate, the salt intensity Q can be expressed in the following formula.

[0084]

[0085] Where C indicates the molar concentration of the corresponding salt, namely NaCl, NaBic, KCl, CaCl2, MgCl2, Na3Cit, and NaAc.

[0086] After several transformations, the following simplified equation is obtained:

[0087]

[0088] In the computational model, the molar conductivity Λi of each salt is calculated based on the following equation:

[0089]

[0090] Where: i = NaCl, KCl, CaCl2, MgCl2, NaAc, Na3Cit, NaBic, glucose.

[0091] [The parameter a can be found in the literature] x,i For example, from the following publications: “Equivalent Conduit of Electrolytes in Aqueous Solution” and “Electrical Conduit of Aqueous Solutions” in the CRC Handbook of Chemistry and Physics, Internet Edition 2007 (87th edition), edited by David R. Lide, Taylor and Francis, Boca Raton, FL.

[0092] The conductivity distribution of salt is calculated as follows:

[0093]

[0094] Calculate the expected value CD of conductivity used in the result data set.D,exp As the sum of all conductivity distributions, where:

[0095]

[0096] In a preferred embodiment of the present invention, the component parameter includes glucose concentration. The glucose concentration represents the molar concentration of glucose in component A.

[0097] According to another advantageous embodiment of the invention, the method or operating method for the mixing device additionally (after the calculation result data set) includes the following method steps:

[0098] - Based on the resulting data set, control commands are generated to manipulate the mixing equipment to mix the dialysis fluid for the dialysis machine according to the formula.

[0099] According to another advantageous embodiment of the invention, a control command is generated only if a confirmation signal indicating that the recipe has been approved has been detected (by the user).

[0100] It will be apparent to those skilled in the art that the calculated result data set can be subjected to automatic checks. Here, it is possible to check, for example, whether the calculated result data set conforms to usual standard values. Furthermore, it is possible to perform a reasonableness check on the calculated result data set.

[0101] In another aspect, the present invention relates to a computing unit for calculating a set of result data based on a calculation model for the conductivity of a dialysate to prepare a dialysate composed of multiple components, the computing unit having:

[0102] - A read interface that determines a set of mixing ratio data for reading, the set of mixing ratio data representing the mixing ratio of at least one component A (concentrate A) and - optionally component B (concentrate B) and - another (or possibly a third) component (RO water);

[0103] - A component interface that determines component parameters for detection, the component parameters including a first substance concentration parameter and a second substance concentration parameter, the first substance concentration parameter representing the concentration of a substance and, in particular, the concentration of a salt in component A, and the second substance concentration parameter representing the concentration of a substance and, in particular, the concentration of a salt in component B;

[0104] - A processor that determines a set of result data for calculating the composition of the dialysate, the set of result data including: a description of the concentration of substances in the dialysate in the mixture to be produced and a description of the expected value of the conductivity of the dialysate based on a calculation model.

[0105] The computing unit may include an output unit (e.g., a graphical user interface). The computing unit may additionally include:

[0106] - A user interface, through which an acknowledgment signal can be received; and / or

[0107] - A memory used to store the confirmed recipe.

[0108] According to another preferred embodiment of the invention, the computing unit may additionally include:

[0109] - Sensor interface, which is used to receive sensor signals regarding the conductivity of the measured dialysis fluid;

[0110] Furthermore, the calculation unit is configured to compare the measured conductivity of the dialysate with, for example, a desired preset consistency from the formulation and / or compare the measured conductivity of the dialysate with the calculated desired value of the conductivity, so as to issue an error notification in case of a lack of consistency. In the event of consistency, a verification signal can be issued, which initiates the delivery of the dialysate to the dialysis machine.

[0111] In another aspect, the present invention relates to a mixing apparatus for preparing a dialysis fluid composed of multiple components, the mixing apparatus having:

[0112] - The interface to the computing unit, as described above;

[0113] - A connection to the first container used to provide component A;

[0114] - Optionally: A connection to the second storage container B for providing component B;

[0115] - A third connection to the third container used to supply RO water;

[0116] - A mixing mechanism for mixing dialysis fluid in a mixing chamber with at least component A, optionally component B, and RO water, based on a preset set of result data provided by a computing unit.

[0117] The mixing equipment can operate in different operating modes. Therefore, the 1MIX method can be used, in which only component A, containing acid and salt, is mixed with RO water. Similarly, the 2MIX method can be used, in which component B (especially one that does not contain acid) is mixed with RO water in addition to component A. Furthermore, the 3MIX method can be used to mix with other customized components.

[0118] In another aspect, the present invention relates to an operating method for such a mixing device, wherein a mixing mechanism for mixing dialysis fluid is controlled by means of a control command, wherein the control command is calculated from a set of result data.

[0119] Preferably, the operating method automatically checks whether the corresponding storage containers (e.g., in the form of cans) for the ingredients (or contents) indicated in the formulation have been connected to the mixing equipment or dialysis machine or used for mixing by comparing the consistency of the ingredient identification codes on the corresponding storage containers with the respective stored references. This advantageously eliminates errors based on incorrect selection of concentrate bags.

[0120] In another aspect, the present invention relates to a dialysis machine having such a computing unit and / or having such a mixing device.

[0121] The computing unit is an electronic component. The computing unit can be configured in hardware and / or software and is used to calculate a set of result data with desired values ​​of conductivity related to the composition of the dialysate.

[0122] The invention has been described above and below with respect to dialysis machines, such as hemodialysis or peritoneal dialysis devices. However, it will be apparent to those skilled in the art that the invention is equally applicable to or adaptable to other medical technologies, computer-controlled devices or (fluid management) machines or blood therapy devices that must deliver dialysis fluid mixed in a specific concentration ratio.

[0123] Dialysis fluid is a dialysis solution that typically contains dissolved substances, such as:

[0124] - Electrolytes Na, K, Mg, and Ca, in order to maintain acceptable electrolyte metabolism in patients;

[0125] - Buffer solutions (e.g., bicarbonate, acetate, lactate, etc.)

[0126] - Glucose (or other osmotic agents), used as osmotic agents in peritoneal dialysis or to maintain blood glucose levels during hemodialysis;

[0127] - An acid, or a salt of an acid (e.g., HCl or Cl, acetic acid, citric acid, etc.), which may help neutralize the alkaline dialysis solution or exist as a counterion in electrochemical equilibrium.

[0128] The formulation is a confirmed set of results data. Therefore, only mixtures of the following components used in the dialysis fluid are stored in the system or memory as formulations, which conform to predefined target presets, such as standard and limit values ​​required during dialysis.

[0129] Another objective solution is a computer program product that is loaded into or can be loaded into the memory of a computer or dialysis device, the computer program product having a computer program that, when executed on the computer or dialysis device, performs the methods described in detail above.

[0130] Another objective solution proposes a computer program that, when executed on a computer, electronic, or medical device, performs all the method steps of the method described in detail above. Here, it is also possible to store the computer program on a medium readable by the computer, electronic, or medical device. Attached Figure Description

[0131] In the following detailed description of the accompanying drawings, embodiments, features, and other advantages, which are not to be construed as limiting, are discussed with reference to the drawings.

[0132] Figure 1 An exemplary view illustrates a dialysis apparatus having a mixing device, a separate computing unit, and an exemplary container for the components to be mixed, according to an advantageous embodiment of the invention.

[0133] Figure 2 It is an alternative configuration for a dialysis device with an integrated container and an integrated mixing device and a computing unit integrated therein.

[0134] Figure 3 A schematic diagram showing a computing unit and a group of signals or data read and output according to another embodiment of the present invention is provided.

[0135] Figure 4 This is an exemplary schematic diagram of an inspection process for checking mixed dialysis fluid based on conductivity measured by a sensor, and related controls.

[0136] Figure 5 This is a flowchart of a method according to an advantageous embodiment of the present invention. Detailed Implementation

[0137] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0138] Figure 1 The diagram schematically illustrates a dialysis machine or a dialysis unit (DG) with other modules. For dialysis treatment, dialysis fluid (df) must be supplied to the dialysis unit (DG). The dialysis fluid (df) is a mixture of various concentrates or components according to a preset or user-defined formula. Typically, these components are supplied in separate containers (1A, 1B, 1C).

[0139] For the dialysis fluid df required for extracorporeal blood therapy, it is possible to—such as in Figure 1 As shown in the diagram, mixing is performed via a separate mixing device M. Dialysis fluid df can be prepared by mixing (wet / dry) concentrate (acidic component A, alkaline component B) with RO water according to a specific, prescribed mixing ratio. Typically, the RO water is available through a central RO water treatment system within the dialysis station.

[0140] Dialysis fluid (df) is an aqueous solution of electrolytes, buffers, and optionally glucose. Patients requiring dialysis often have kidneys that are no longer sufficient to excrete acid via urine, increasing the risk of potential acidosis. To balance acid / base metabolism, the dialysis fluid should have a pH value corresponding to that of a healthy person. For this purpose, acidic and alkaline components (components A and B, or concentrates) are mixed with RO water. Sodium bicarbonate powder (NaHCO3) dissolved in RO water is typically used as the alkaline component. By mixing with RO water, sodium and bicarbonate are produced in the resulting dialysis fluid. Bicarbonate acts as a pH buffer in the patient's blood. During dialysis, bicarbonate diffuses through the membrane of the dialysis filter into the patient's blood and "buffers" the desired pH value in the blood, that is, keeps it stably at a certain value.

[0141] This invention is based on the monitoring of the composition of dialysis fluid, and in particular on the monitoring of conductivity by comparing it with expected values.

[0142] To date, in order to determine the conductivity of the mixed dialysate, the volume fractions for concentrate A (e.g., 1L) and B (e.g., 1.83L), and the values ​​for RO water (e.g., 34L), as specified on the concentrate vessel, have been entered into the dialysis apparatus. Additionally, the concentrations of electrolytes (Na, K, Ca, Mg, acetate, citrate, bicarbonate, glucose, etc.) and the concentration of the acid (acetic acid or hydrochloric acid) in the mixed dialysate df are entered, the concentrations derived from the specific mixing ratio. These specifications are also given on the concentrate vessels or concentrate containers 1A and 1B.

[0143] In this case, the concentrations of substances described on the concentrate containers 1A and 1B relate to the given mixing ratio of components A, B, and RO water. Typically, this mixing ratio remains unchanged. However, it is possible to alter the values ​​of the sodium concentration and bicarbonate concentration, for example, to achieve a specific therapeutic goal (setting the sodium level in the patient's blood).

[0144] The change in these values ​​also automatically causes a change in the aforementioned mixing ratio. That is, in this case, the electrolyte concentrations stated on concentrate containers 1A and 1B are no longer consistent with reality. Therefore, the current method is susceptible to error, especially when the concentration of substances is changed by the user. This is due to the following technical background: sodium concentration and acid concentration are interrelated because their concentrations change due to chemical reactions with substances in other concentrate containers.

[0145] To address the problems described above in existing systems, this invention proposes, instead of electrolyte concentration, inputting the concentrations of salts (NaCl, KCl, etc.) and acids (acetic acid, citric acid) of the concentrate (in its unmixed state) into the dialysis apparatus. These values ​​must be standardized and always provided entirely by the manufacturers of the concentrate containers 1A, 1B. These values ​​can be entered either manually by the user or automatically (e.g., via a correspondingly applied identification code, which is read and automatically associated with the corresponding contents through an electronically stored table). According to this invention, using a mathematical-chemical calculation model, the electrolyte or substance concentration in the fully mixed dialysis fluid df and the resulting expected conductivity of the dialysis fluid df are calculated from the data.

[0146] As in Figure 1 As shown, the mixing device M can be controlled via control command sb, which receives the control command sb from a computing unit R—separate in this embodiment. The control command controls the mixing mechanism of the mixing device and performs calculations based on a set of result data. The mixing device is used to mix and prepare dialysate df, which is then transferred to the dialysate device DG.

[0147] Different containers used for mixing the components of dialysis fluid df can be equipped with identification codes. Therefore, component A contained in container A 1A is indirectly identified by identification code 1Ai. Thus, the corresponding identification code mathematically identifies the container one-to-one and indirectly indicates the contents and / or the concentration of substances contained within the contents (especially salt concentration). Container B 1B, containing component B or a concentrate of component B, is, for example, equipped with identification code 1Bi. The identification code can be a digital code (barcode, QR code) or other identification tag (NFC tag) affixed to the container. The correlation between the code and the container is stored in the computing unit R. Therefore, it is possible to check in the computing unit R whether the corresponding correct container is connected or used for mixing for each preset formulation of dialysis fluid df. This will be discussed in the following... Figure 5 The inspection will be described in detail.

[0148] Exemplary in Figure 1The system architecture shown in the figure, which has independent modules M, R, and DG, can also be changed.

[0149] Figure 2 An alternative embodiment of the invention is shown, in which the dialysate df is mixed by the dialysate device DG itself. In this example, the dialysate device DG includes the aforementioned module of the mixing device M and a computing unit R integrated therein. It also includes chambers or containers 1A, 1B, 1C, and 1D for mixing the various concentrates of the dialysate df. In this example, four components are used. The number of components is variable. Typically, three components (two concentrates and RO water) are mixed. It will be apparent to those skilled in the art that other variations of the architecture are within the scope of the invention. Thus, for example, specific modules can be connected as independent modules, such as containers, via corresponding connections, which can be provided as mobile units and connected to the dialysate device DG via corresponding hose connections.

[0150] Figure 3 A computing unit R according to another embodiment with further details is shown. The computing unit R includes a processor P, which acts as a calculator for performing calculations. The processor P exchanges data with a memory MEM storing a calculation model BM and another memory that can be configured as a database DB. A large number of validated recipes are stored in the database DB. In alternative embodiments, the database DB and / or the memory MEM can also be moved out, allowing for a narrower (smaller) computing unit. The computing unit R further includes different interfaces: an input interface 31 for reading mixing ratio data set 311; and an interface 32 for detecting component parameters, particularly for detecting a first concentration parameter 322-1 and a second concentration parameter 322-2. These two concentration parameters relate to concentrates from containers 1A, 1B (and optionally other containers or components). Concentration parameters 322-1, 322-2 preferably include the salt concentration in the corresponding component. These concentration parameters do not particularly relate to the dialysate df to be mixed, as proposed in the prior art. All necessary information regarding the concentrate parameters can be obtained from the instructions located on the container, or these instructions—as described above—can be automatically detected. The detected and read data is then transferred to the processor P.

[0151] Processor P is used to calculate result data set 331. Result data set 331 can first be output to the user interface (UI) for user confirmation, and then sent to the mixing device M via interface 33 by means of control commands for execution on the mixing device. Result data set 331 details the composition of the dialysate df to be mixed. Result data set 331 includes descriptions of the substance concentrations of the dialysate df to be mixed, particularly regarding electrolyte and salt concentrations, and a description of the expected value of the conductivity for the liquid df to be mixed. The calculation by processor P is based on computational model BM. Result data set 331 is sent to the user interface (UI), which can be designed as a graphical user interface. Thus, the user has the option to confirm result data set 331 by means of confirmation signal 34. This occurs particularly when the obtained substance concentrations in result data set 331 are within the standard range for dialysis. Only when a confirmation signal is input, the corresponding mixing ratio data set is suitable as an acceptable formulation for the dialysate df and can be stored in the database DB. Otherwise, the user will be required to make other inputs and / or an error notification will be sent on the interface UI by means of other instructions. The result data set 331 is then transferred to the mixing device M for mixing the dialysis fluid df. Here, the result data set is enriched by control command sb, which allows the mixing device to be controlled such that the stored formula is obtained and then provided to the dialysis device DG.

[0152] In addition to the mixing ratio data set 311 and component parameters 322-1, 322-2, ... 322-n (based on the amount of components to be mixed), input variables for the automated calculation method include a description of the volume of dissolved salt. Furthermore, it is feasible to also detect other metadata as input variables (timestamps, databases, etc.).

[0153] This invention proposes a dedicated menu guide that directs the user step-by-step through the necessary inputs required for calculation. The user is guided via an input menu through corresponding masks on the screen surface. This reduces the risk of errors. After the data required for the calculation is entered, the calculation is automatically performed to provide a set of result data 331 (particularly on the user interface).

[0154] If a computing unit R is used to monitor the mixing device M, then the computing unit R includes, in addition to the interfaces mentioned above, another interface 34 for detecting sensor signals for the measured conductivity 41 of the dialysate produced by the mixing device. For this purpose, the computing unit R receives signals from at least one (preferably multiple) conductivity sensors S via interface 34 and transmits the conductivity signal 41 to the processor P for checking to ensure that the conductivity is within the desired range defined by the formulation and / or in the result data set 331. This allows for continuous monitoring of the mixing device M, which generally improves the safety of the dialysis machine (DG).

[0155] Figure 4 The invention illustrates the use of a computing unit R to check whether the mixed dialysate df conforms to the preset formulation, and particularly for checking the composition of substances. For this purpose, sensors S for measuring the conductivity of the dialysate df are preferably located at different positions. In a preferred embodiment of the invention, multiple sensors S can be provided to redundantly detect conductivity at different locations (e.g., at the mixing device M, in the connection between the mixing device M and the dialysate DG, and / or at the dialysate DG itself). The sensors S send their measurement results, with the currently measured conductivity 41, as signals to the computing unit R for checking. The computing unit is located via interface 34 (in... Figure 4 (Not shown in the image) Receives conductivity values. The computer unit R stores the desired preset and / or the recipe with result data set 331. When consistent, as planned, the mixed dialysis fluid df is transferred to the dialysis device DG without further notification. If the currently measured conductivity 41 does not correspond to the preset or desired value, then an error notification 43 is output. Error notification 43 can be received on the mixing device (in the image). Figure 4 (Indicated by an arrow pointing towards the mixing device M) and / or issued on the dialysis device DG and / or on the central control and monitoring unit, so that corrective measures can be taken. The latter in Figure 4 The error report 43 is indicated by a downward-pointing arrow. In principle, the computing unit R provides control commands sb to operate and control the mixing device according to the preset parameters of the result data set 331. In this case, the computing unit R also additionally undertakes the task of controlling and regulating the mixing device M.

[0156] Figure 5This is a flowchart of a method for inputting parameters for the concentrate. After the start of the method, in step 51, a description of the desired mixing ratio is read. Here, in particular, the mixing ratio data set is read. This can be performed by means of user input on a user interface (e.g., the surface of the computing unit R). In this embodiment, the description is user-defined. Alternatively, it is also possible to pre-define the data mentioned above and read it from memory via interface 31. In step 52, the component parameters, namely the first salt concentration parameter 322-1 and the second salt concentration parameter 322-2, are detected. In this embodiment, the first substance concentration parameter and the second substance concentration parameter are referred to as salt concentration parameters. In the first embodiment of the invention, the description can be detected either via a user interface (UI). Alternatively, in the second embodiment of the invention, the description can be detected automatically via interface 32, for which data exchange is performed with electronic descriptions on containers 1A and 1B. Therefore, in addition to the identification indication, the identification codes 1Ai and 1Bi can, for example, also include another data area in which the corresponding salt concentration parameters 322-1 and 322-2 of the corresponding components are represented. The other data area can also be independent, for example, provided as a QR code on the container of the concentrate manufacturer. Alternatively, a correlation table can be stored in the calculation unit R, which stores component parameters with corresponding identification codes for the concentrate or ingredients. By accessing the table (e.g., a lookup table), the component parameters can also be automatically detected in the third variant of step 52.

[0157] In other words, after inputting data, the resulting dialysis fluid parameters are calculated. For each concentrate, a table-type list can be displayed within a built-in screen mask, the list including the resulting electrolytes and conductivity for the corresponding concentrate (by means of a one-to-one assigned ID number). This list can be checked, particularly to ensure compliance with predefined allowable values ​​or ranges.

[0158] In step 53, the result data set 331 is calculated by accessing the computational model BM. In step 54, it is checked whether the resulting concentration is within a predefined standard range for dialysis. If not, a warning notification is output in step 56. Optionally, an instruction can also be sent on the user interface (UI) informing the user of an incorrect formulation and providing further indications of which values ​​are critical for exceeding the limits. If the check in step 54 is successful, the formulation can be confirmed in step 56. Subsequently, in step 57, only the confirmed formulation can be saved in the memory database (DB). The method then ends or is repeated.

[0159] Operating methods for hybrid devices that can be integrated into a dialysis machine's DG or connected as a stand-alone device to a dialysis machine's DG can, for example, have the following processes:

[0160] In the service menu, enter a new formulation suggestion for the dialysis fluid. In the formulation suggestion, select the mixing ratio (mixing ratio data group: Concentrate A, Concentrate B, RO water), and enter the salt and optionally acid concentrations and optionally glucose concentrations (glucose is an optional component) as ingredient parameters in the menu. For identification purposes, it is also possible to associate an ID number with the formulation suggestion.

[0161] The saved computational model is then used to check the formulation recommendations, whereby the concentrations of substances produced by the dialysis fluid prepared according to the recommendations are determined and displayed in a screen view. In this case, atypical values ​​are highlighted (e.g., against a yellow background). Automated checks for desired formulations can also be performed, such as checking for adherence to standard ranges and / or predefined limits. The operator can then either discard the formulation or add it to the dialysis device's formulation catalog, which allows for formulation selection.

[0162] In subsequent stages, it is possible to monitor whether the mixing equipment follows the formulation determined according to the method described above. For this purpose, the calculation unit R or the dialysis equipment DG having the calculation unit R is configured such that the internally or externally determined formulation and, in particular, the calculated result data set are used to prepare and monitor the dialysis fluid accordingly by means of a suitable mechanism. In this case, the dialysis equipment has a device or connection for connecting the concentrate container and RO water, and a device (metering pump, mixing chamber, etc., not shown in the figures) for conveying and mixing components according to the selected formulation, and a conductivity sensor S, preferably in the fresh dialysis fluid line, which is used to monitor conductivity in terms of the expected value of conductivity calculated in the result data set. It will be apparent to those skilled in the art that the temperature of the dialysis fluid can be adjusted to a physiologically meaningful value, and conductivity measurements can be performed with temperature compensation.

[0163] The proposed solution offers the following technically advantageous effect: redundant detection of concentrate parameters 322-1 and 322-2. This has the advantage of enabling the identification of errors caused by instructions on concentrate containers 1A and 1B (involving different mixing ratios than the formulation). Errors may arise, for example, by printing two contradictory instructions on the concentrate bag. Thus, when concentrate A is diluted with a factor of 1:34, the electrolyte concentration stated in the first region is produced, for example. However, in practice, when preparing the dialysate (according to the instructions in the second region), concentrate A is diluted with a factor of 1:36.83. Advantageously, it is therefore possible to automatically identify when the given electrolyte concentration involves a dilution or mixing ratio different from the dilution or mixing ratio corresponding to the formulation.

[0164] Furthermore, incorrectly printed values ​​can also be identified in the contents lists on concentrate bags 1A and 1B. For example, if the acetate concentration is stated as 3.0 mmol / L in the first list on bag 1A, and as 0.3 mmol / L in the second list on another bag 1A', even though the same amount of acetic acid (H acetate) is weighed in both A concentrates, the source of the error can be automatically identified.

[0165] In summary, a significant advantage of the proposed method is that the computational model for determining the conductivity of a dialysate composed of a concentrate with multiple electrolyte components and RO water considers only the total concentration of all electrolyte components to determine the molar conductivity; this is also known as the salt strength Q. The correlation between the individual electrolyte components is not considered. Testing has confirmed that this simplification enables accurate modeling of the conductivity of the resulting dialysate, thus providing high-quality results.

[0166] Finally, it should be noted that the description and embodiments of the present invention should not be construed as limiting in principle regarding any particular physical implementation of the invention. All features set forth and illustrated in connection with the various embodiments of the invention can be presented in different combinations within the subject matter of the invention in order to simultaneously achieve their advantageous effects. Thus, alternatively to or cumulatively provided with the graphical user interface, such as for input confirmation signals, other operational or control elements for the computing unit R can be provided, for example, within the scope of the invention. The hybrid device M and the computing unit R are typically integrated within the dialysis device DG. However, it will be particularly apparent to those skilled in the art that other architectures with independent data exchange units can also be used without departing from the inventive concept. In contrast, components of a medical system can be implemented in a manner distributed across multiple physical products.

[0167] The invention is not limited by the features set forth in the description or shown in the drawings.

[0168] Figure Labels

[0169] DG dialysis equipment

[0170] 1AA Concentrate Container

[0171] 1BB Concentrate Container

[0172] 1C Third Container, especially for RO water

[0173] 1Ai is the identification code used for A concentrate containers.

[0174] 1Bi identification code for B concentrate containers

[0175] M mixing equipment

[0176] R Calculation Unit

[0177] sb control commands

[0178] P processor

[0179] UI (Graphical User Interface)

[0180] DB is a memory used to store confirmed recipes.

[0181] MEM is a memory used to store computational models and / or data.

[0182] 31 Read Interface

[0183] 32-component interface

[0184] 33 Structured Data Interface

[0185] 34. Interface for reading the conductivity measured by the sensor

[0186] 331 Results Data Group

[0187] 311 Mixing Ratio Data Set

[0188] 322-1 First Concentration Parameter

[0189] 322-2 Second Concentration Parameter

[0190] BM computational model

[0191] 34 Confirmation Signal

[0192] S is a sensor used to measure conductivity.

[0193] The conductivity measured in 41

[0194] 42 verification signals

[0195] Error 43

[0196] df dialysis fluid

[0197] 51 Read the mixing ratio data set

[0198] 52 Detection Component Parameters

[0199] 53 Calculation Results Data Set

[0200] 54. Check whether the obtained concentration is within the standard range.

[0201] 56 confirmed as a formula

[0202] 57 Storage Formula

Claims

1. A method for controlling the preparation of a dialysate based on a computational model (BM) of the conductivity of a dialysate (df) to be mixed with multiple components, the method comprising the following steps: - Read (51) the mixing ratio data set (311), which represents: A mixing ratio of at least one component A and one component B with a third component; or a mixing ratio of at least one component A with a third component; - Detect (52) component parameters, the component parameters including a first substance concentration parameter (322-1); or the component parameters include a first substance concentration parameter (322-1) and a second substance concentration parameter (322-2), the first substance concentration parameter representing the concentration of the substance in component A, and the second substance concentration parameter representing the concentration of the substance in component B; - Calculate (53) the resulting data set (331) of the composition of the dialysate (df), the resulting data set including a description of the concentration of substances in the dialysate based on the calculation model (BM) and a description of the expected value of the conductivity of the dialysate. - Based on the mixing ratio data set (311), a control command (sb) is generated for the mixing device (M) to generate the dialysis fluid (df) according to the mixing ratio data set (311).

2. The method according to claim 1, wherein, The method includes the following steps: - Check (54) whether the concentrations of substances derived from the calculated result data set (331) are within the predefined standard range, and if so, save the mixing ratio data set (311) as a confirmed formulation for the dialysis fluid.

3. The method according to claim 2, wherein, In the event of a successful check, the read mixing ratio data set (311) is used as a recipe, wherein an ID number is associated one-to-one with the recipe.

4. The method according to any one of claims 1 to 3, wherein, The method additionally includes the following method steps: - Display the concentration of the substance, and / or - A warning notice is issued if the concentration of the substance is not successfully checked to be within the standard range.

5. The method according to any one of claims 1 to 3, wherein, The substance concentration is a salt concentration, and the calculation model (BM) is based on salt strength, which is a measure of the sum of all molar concentrations of all salts, and the conductivity is related to the salt strength in the calculation model (BM).

6. The method according to claim 2 or 3, wherein, The component parameters include glucose concentration.

7. The method according to claim 6, wherein, A control command is generated only when a confirmation signal indicating that the recipe has been approved has been detected.

8. A calculation unit (R) for preparing a dialysis fluid (df) composed of multiple components by calculating a dataset (331) based on a calculation model (BM) for the conductivity of the dialysis fluid, the calculation unit having: - Reading interface (31), the reading interface being determined for reading a mixing ratio data set (311), the mixing ratio data set representing a mixing ratio of at least one component A and a component B and a third component; - Component interface (32), the component interface determines the component parameters for detection, the component parameters include a first substance concentration parameter (322-1) and a second substance concentration parameter (322-2), the first substance concentration parameter represents the concentration of the substance in component A, and the second substance concentration parameter represents the concentration of the substance in component B; - A processor (P) that determines a set of result data (331) for calculating the composition of the resulting dialysis fluid (df) to be produced, the set of result data including a description of the concentration of substances in the dialysis fluid and a description of the expected value of the conductivity of the dialysis fluid based on a computational model (BM), wherein the computational model (BM) is based on salt strength, which is a measure of the sum of all molar concentrations of all salts, and in the computational model (BM), the conductivity is related to the salt strength.

9. The computing unit (R) according to claim 8, wherein the computing unit additionally comprises: - User interface (UI), through which confirmation signals can be received; and / or - Memory (DB), which is used to store validated recipes.

10. The computing unit (R) according to claim 8 or 9, wherein the computing unit additionally comprises: - Sensor interface (34), the sensor interface being used to receive sensor signals regarding the measured conductivity (41) of the dialysis fluid (df); Furthermore, the calculation unit (R) is configured to compare the measured conductivity (41) of the dialysis fluid (df) with the expected preset and / or the expected value calculated, so as to issue an error notification in case of a lack of consistency.

11. A mixing apparatus (M) for preparing a dialysate (df) for a dialysis machine (DG) consisting of multiple components, said mixing apparatus having: - An electronic interface that connects to a computing unit (R) according to any one of claims 8 to 10. - Connection to the A section leading to the first container (1A) for providing component A; - Connection to the B section for providing component B to the second container (1B); - A third connection to the third container (1C) used to supply RO water; - A mixing mechanism for mixing the dialysis fluid (df) in a mixing chamber with at least the A component, the B component and the RO water according to a preset of one of the result data sets (331) provided by the computing unit (R). or The mixing device has: - An electronic interface that connects to a computing unit (R) according to any one of claims 8 to 10. - Connection to the A section leading to the first container (1A) for providing component A; - A third connection to the third container (1C) used to supply RO water; - A mixing mechanism for mixing the dialysis fluid (df) in a mixing chamber with at least component A and RO water according to a preset of one of the result data sets (331) provided by the computing unit (R).

12. A method of operating a mixing device (M) according to claim 11, wherein a mixing mechanism for mixing dialysis fluid is controlled by means of a control command (sb), wherein, The control command (sb) is calculated from the result data set (331).

13. The operating method according to claim 12, wherein the operating method is used to monitor the mixing device (M) and the dialysate (df) mixed by means of the mixing device, by measuring the current conductivity of the prepared dialysate (df) and comparing it with a desired preset and / or with a calculated desired value, so as to issue an error notification in case of inconsistency.

14. The operating method according to claim 13, wherein, Automatic check: For the contents indicated in the result data set (331) and / or in the formulation, whether the corresponding containers (1A, 1B, 1C, 1D, ...) have been connected to the mixing device (M) for mixing, by comparing the contents identification code at the corresponding containers (1A, 1B, 1C, 1D, ...) with the respective stored references.

15. A dialysis machine (DG) having a computing unit (R) according to any one of claims 8 to 10.

16. A dialysis machine (DG) having a mixing device (M) according to claim 11.

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