EP3755395A1

EP3755395A1 - Model-based mixing of a dialysis fluid for a dialysis device

Info

Publication number: EP3755395A1
Application number: EP19706535.2A
Authority: EP
Inventors: Pia Daniel; Alfred Gagel; Carsten Mueller; Christoph Wiktor
Original assignee: Fresenius Medical Care Deutschland GmbH
Current assignee: Fresenius Medical Care Deutschland GmbH
Priority date: 2018-02-21
Filing date: 2019-02-18
Publication date: 2020-12-30
Also published as: WO2019162227A1; DE102018103845A1; CN111757763A

Abstract

The present invention relates to a method and a calculation unit (R) and also a mixing device (M) for calculating a result data set (331) for composing a dialysis fluid (df) to be mixed, composed of several components, on the basis of a calculation model (BM) for the conductivity of the dialysis fluid, having the following method steps: - inputting (51) a mixing ratio data set (311) which represents a mixing ratio of at least one A component and one B component and a third component; - acquiring (52) component parameters, comprising a first substance concentration parameter which in particular represents the concentration of salt in the A component, and a second substance concentration parameter which in particular represents the concentration of salt in the B component; - calculating (53) the result data set (331) for the resulting composition of the dialysis fluid, comprising a statement of substance concentrations in the dialysis fluid and an expected value for the conductivity of the dialysis fluid based on the calculation model (BM).

Description

Title: Model-based mixture of a dialysis fluid for a dialysis machine

description

The present invention relates to a monitored and model-based mixture of a dialysis fluid for a dialysis machine. It relates in particular to a mixing device, to a dialysis machine with such a mixing device and to a method for operating the mixing device.

Dialysis machines are blood treatment devices in which a patient's fluid is delivered via a fluid line to a fluid treatment component, treated by the fluid treatment component, and returned to the patient via the fluid line that can be divided into an arterial and a venous branch. Examples of such blood treatment devices are in particular flämodialysegeräte. Such a blood treatment device is the subject of DE 198 49 787 C1 of the Applicant, the content of which is hereby incorporated in full in the disclosure of the present application.

Dialysis is a procedure for purifying the blood of patients with acute or chronic renal insufficiency. Basically, a distinction is made here between methods with an extracorporeal blood circulation, such as flämodialysis, flämofiltration or flämodiafiltration and peritoneal dialysis, which has no extracorporeal blood circulation.

The blood is passed in the flaemodialysis in an extracorporeal blood circulation through the blood chamber of a dialyzer, which is separated by a semipermeable membrane of a dialysis fluid chamber. The dialysis fluid chamber is traversed by a blood electrolyte contained in a certain concentration dialysis fluid. The substance concentration of the blood electrolytes in the dialysis fluid corresponds to the concentration of blood electrolytes in the blood of a healthy person. During the treatment, the patient's blood and the dialysis fluid on both sides of the semipermeable membrane are generally passed countercurrently at a predetermined flow rate. Urinary substances diffuse through the membrane from the blood chamber into the dialysis fluid chamber, while electrolytes present in the blood and dialysis fluid diffuse from the higher concentration chamber to the lower concentration chamber, respectively. If a pressure gradient from the blood side to the dialysate side is established on the dialysis membrane, for example by a pump which withdraws dialysate from the dialysate circuit downstream of the dialysis filter on the dialysate side, water comes out of the dialysate

Patient blood via the dialysis membrane in the dialysate over. This process, also referred to as ultrafiltration, leads to a desired dehydration of the patient's blood.

In hemofiltration ultrafiltrate is withdrawn from the patient's blood by applying a transmembrane pressure in the dialyzer without dialysis fluid being passed on the side of the membrane of the dialyzer opposite the patient's blood. In addition, a sterile and pyrogen-free substituate solution can be added to the patient's blood. Depending on whether this Substituatlösung is added upstream of the dialyzer or downstream, it is called pre- or post-dilution. The mass transfer takes place at the

Haemofiltration convective.

Hemodiafiltration combines the methods of hemodialysis and hemofiltration. There is both a diffusive mass transfer between the patient's blood and dialysis fluid via the semipermeable membrane of a dialyzer instead, as well as a filtration of plasma water contained in the blood by a

Pressure gradients on the membrane of the dialyzer.

The methods of hemodialysis, hemofiltration and hemodiafiltration are usually performed with automatic hemodialysis machines, such as those sold by the applicant. Plasmapheresis is a blood treatment procedure in which the patient's blood is separated into the blood plasma and its corpuscular components (cells). The separated blood plasma is purified or replaced with a substitution solution, and the purified blood plasma or the substitution solution is returned to the patient.

In peritoneal dialysis, the abdominal cavity of a patient is filled via a guided through the abdominal wall catheter with a dialysis fluid having a concentration gradient of blood substances such as electrolytes (for example, sodium, calcium and magnesium) against the body's own fluids. About the acting as a membrane peritoneum (peritoneum) occur in the body toxins from the running in the peritoneum blood vessels in the abdominal cavity. After a few hours, the dialysis fluid in the abdominal cavity of the patient, now mixed with the toxins transferred from the body, is exchanged. Osmotic processes allow water from the patient's blood to pass through the peritoneum into the dialysis fluid and drain the patient.

The method for peritoneal dialysis is usually carried out with the aid of automatic peritoneal dialysis machines, such as those sold by the Applicant. The dialysis fluid for the dialysis machines is usually produced by mixing at least two dialysis concentrates with RO water (RO = reverse osmosis). To prepare the dialysis fluid, a water tank for the RO water and containers for different concentrates or components for producing the dialysis fluid can be used. The concentrates can be provided in solid and / or liquid form.

In certain types of treatment, such as "bicarbonate hemodialysis", two dialysis concentrates are usually used, which are diluted with the RO water in defined amounts before the dialysis treatment and are mixed with one another to give the so-called dialysis fluid acidic concentrate (A component) and a basic one Concentrate (B component). The basic concentrate usually consists of a sodium bicarbonate solution of defined concentration. The acidic concentrate contains all the other ingredients necessary for the dialysis treatment. These are mainly the electrolytes sodium, potassium, calcium, magnesium and moreover the components chloride, acetate. The acidic concentrate may also include glucose.

In a first method for producing the dialysis fluid, the mixture is carried out by means of a volumetric mixing method in which water and concentrate are mixed with one another in a certain predetermined volumetric ratio.

A second method for the production of dialysis fluid is the conductivity-controlled method, in which the ratio of the water and concentrate components is controlled so that in the final dialysis a certain conductivity is established, resulting from the electrolyte or substance concentrations in the final dialysis. This second conductivity controlled method aims to improve the present invention.

To ensure the safety of the treatment, the composition of the dialysis fluid is monitored. In particular, the standard ISO EN DIN 60601-2-16 requires dialysis machines to monitor the composition of the sodium and bicarbonate dialysis fluid. The protection system must be defined

Recognize deviations from preset target values and protect the patient from the danger.

In conductance-controlled dialysis machines, the conductivity of the ready-mixed dialysis fluid is used as the measured variable. The expected value of the conductivity with the specified setpoint values is calculated on the basis of the electrolyte

Calculated concentrations in the dialysis fluid. For this purpose, the electrolyte concentrations must be known to the device.

Often in dialysis machines, the concentrations of the individual electrolytes (Na, K, Ca, Mg, Cl, acetate, citrate, bicarbonate) and other components (eg, possibly glucose), which result from the prescribed recipe (mixing proportions for RO water, A and B concentrate) entered by the user in a SERVICE menu on a user interface of the device.

However, some devices allow a change or adjustment of the prescribed sodium and bicarbonate values. As a result, if the user adjusts these values, the dosing volumes of the A and B concentrates and thus also the concentrations of all other electrolytes change. In order to be able to calculate these automatically, the machine requires further concentrate parameters, namely the acid concentration originating from the A concentrate and the sodium concentration originating from the B concentrate.

However, the last two values are not in the lists of ingredients that are issued by the manufacturers of concentrates. The acid concentration and the salt concentration have hitherto been entered manually by the user in the prior art. This requires a very special expert knowledge in order to determine them correctly. The further calculation is based on these manual inputs. This procedure is thus error-prone. A normally trained service technician will not be able to do this.

In addition, the following sources of error can not be identified: a) Wrongly printed values in the lists of ingredients on the concentrate containers and b) The specification of the electrolyte concentrates refers to a different dilution ratio than the recipe.

Starting from the known systems for providing the mixed dialysis fluid in the prior art, the present invention has therefore set itself the task to automate the mixing of the dialysis fluid and to improve while maintaining the flexible ability to change the sodium and bicarbonate values. In particular, the composition of the Dialysis fluid to be subjected to an automatic review. Furthermore, the mixture and consequently the overall treatment should be made safer.

This object is achieved by a method, a computing unit, a mixing device and a dialysis machine according to the enclosed, mutually independent claims.

The invention will be described below with reference to the task solution according to the method. As mentioned features, advantages or alternative embodiments are also to be transferred to the other claimed objects and vice versa. In other words, the subject claims (which are directed, for example, to a dialysis machine or to a device) can also be developed with the features described or claimed in connection with the method. The corresponding functional features of the method are formed by corresponding physical modules, in particular by electronic hardware modules or microprocessor modules, the device and vice versa.

The approach proposed here for solving the above-described problem relates to two aspects:

1. A first approach (method) for calculating the ingredients (called components here) for the dialysis fluid, so that the correct mixture of the concentrates or components can be provided with the resulting or intended electrolyte concentrations. For this purpose, a numerical calculation model based on a simplified calculation should be the basis. The data thus calculated are provided as a result data set, which comprises quasi a formulation with an expected value for the conductivity of the resulting dialysis fluid.

2. A second approach (operating procedure) to check whether the previously determined recipe is complied with. Thus, the mixing result should be monitored for compliance with the specifications of the previously determined recipe. These are sensors for measuring the conductivity provided that compare the measured conductivity with the calculated expected value from the result data set. The second method is performed after the first method. Both methods solve the same problem, but in principle can be used independently.

According to a first aspect, the invention relates to a method for calculating a result data set for the composition of a dialysis fluid to be mixed (at least two) to be mixed (for use in a dialysis machine) on the basis of a calculation model for the conductivity of the dialysis fluid, comprising the following method steps:

- Reading a mixture ratio record, the one

Mixing ratio of at least one A component (eg A concentrate, acidic) - and optionally one B component (eg B concentrate, basic, only salts) - and another (or second or third) component (RO water) represents. A component is usually a concentrate or other ingredient. The reading in can take place automatically via an interface from a memory if the mixing ratio data record is predefined.

Alternatively, it can also be user-determined and via a

User interface can be entered by the user. It is also possible to add further constituents or components of the dialysis fluid.

- Detecting component parameters comprising a first substance concentration parameter representing the concentration of a substance in the A component and a second substance concentration parameter representing the concentration of the substance in the B component. The component parameters refer to concentrations in the individual components or concentrates in a not yet mixed state. In particular, they do not relate to concentrations in the dialysis fluid to be mixed (mixed state). The component parameters refer to chemical Details of the components in not yet mixed state (raw state, eg as concentrate).

- Calculate the result data set to the resulting

Composition (in particular resulting from the read-in mixing ratio data set and the detected component parameters) of the (to be produced) dialysis fluid, comprising an indication of substance concentrations (in particular electrolyte concentrations) in the (to be produced) dialysis fluid and an expected value for the Conductivity of the (to be produced) dialysis fluid based on the calculation model. The result data set refers to the mixed state of the dialysis fluid.

In a preferred embodiment of the invention, the method comprises:

- Check if the substance concentrations are calculated from the

Result data set each lie in a predefined normal range and, if so, save the mixing ratio record as confirmed

Formulation for the dialysis fluid.

This embodiment has the advantage that only confirmed formulations can be stored in the system, ie those which fulfill predefinable standard range specifications. Typically, the A-concentrate contains salts and the acid. The B concentrate contains only salts, d. H. no acid.

There are different dialysis methods that differ in number and in the concentrates or components to be mixed. The current bicarbonate dialysis mixes three fluids: A, B concentrate and RO water. In acetate dialysis, only two liquids are mixed: A-concentrate and RO-water In the case of acetate dialysis (mixture of two components), the procedure presented here should also be used. In the 3MIX process, four components or liquids are mixed: A-, B-, Individual Concentrate and RO water. Again, the presented here, inventive proposal applies.

In a preferred embodiment of the invention, the first and second substance concentration parameters relate to the concentration of a particular substance (in particular salt) in the different components in the

unmixed condition. Alternatively, an acid concentration can also be detected for selected components.

According to a further preferred embodiment of the invention, the read-in mixture ratio record acts as a (confirmed) recipe in the case of a successful check, wherein the recipe is uniquely assigned an ID number or an identification code. This can be used very efficiently

Calculations are executed on.

According to another advantageous embodiment of the invention, the method additionally comprises (after calculating the result data set) the following method step (e):

Display of the (mixed state) substance concentrations and / or

- In case of unsuccessful testing of the resulting substance concentrations for compliance with standard ranges: issue a warning message. In another preferred embodiment of the invention, the method of monitoring a mixing device and the blended therewith

Dialysis fluid used by the current conductivity of the prepared dialysis fluid is measured and compared with target specifications (in particular from a recipe) and / or with the calculated expectation value for the conductivity to an error message in case of mismatch

issue.

The substance concentrations are, in particular, salt concentrations. In another advantageous embodiment of the invention, this is based

Calculation model on a salt strength, whereby the salt strength is a measure of the sum of all molar concentrations of all salts, and whereby in the calculation model the conductivity correlates with the salt strength. The calculation model serves to predict the conductivity of the resulting dialysis fluid as a solution containing several different ones

Electrolytes. The calculated result data set can be used for dialysis

be determined with sufficient accuracy.

In the calculation model, the molar conductivity of an electrolyte is thus always calculated the same, regardless of whether a mixture of

multicomponent substances is present. The molar conductivity of the pure

Electrolytes can be read from pre-stored tables for different concentrations.

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

The A-concentrate is solved with the following factor:

V _" x" 1

V mi-x x mix X m "ix

With:

V _a Dosing volume of A concentrate in the respective A pump [mL] Vmix total dialysis fluid volume per batch or mixing cycle

[ML]

The mix ratio record is entered with the sum of all

Ingredients of the mixture (e.g., in a 2MIX process: A Concentrate, B Concentrate and RO Water). After the mixture ratio data set has been entered, the concentrations of each in the

Dialysis fluid salts are computer-based and automatically calculated. The dialyzing fluid mixture ratio with respect to the solution of the A concentrate can be expressed mathematically as follows:

The dialysis fluid concentrations Cx, the substances X in the

Component or can be derived in the concentrate A, can be calculated by

Cx dialysis fluid concentrations of substance X;

mx weighed mass of substance X;

V _a Volume of concentrate A in which the masses mx are dissolved [L]; Mx is the molar mass of the substance X [g / mmol];

Xmix solution factor of the A concentrate. In cases where glucose is to be added, the dialysis fluid concentrations Cc6Hi206 derived from the A concentrate are calculated by:

With:

Cc6Hi206 dialyzing fluid concentration of glucose C6H12O6 [g / L] as an optional ingredient,

neutral mass of glucose weighed

fG correction factor

fG = 1, 0 Correction factor when glucose anhydrate is weighed fG = 1, 1 Correction factor when glucose monohydrate is weighed. The corresponding relationships apply to the solution of the B-concentrate. Thus, in the above formulas, only the component referring to component A is to be replaced by "B".

The calculation model for calculating the expected value for the conductivity of the dialysis fluid to be generated is based on the finding that the chemical bonds between the electrolytes, partially or completely interrupted when the substances are dissolved in water. They then dissociate into positively and negatively charged ions. The mobile charge carriers carry the electricity in the aqueous solution. Increasing electrolyte concentrations C usually increase the conductivity K, which is defined as:

With:

G = l / U conductivity [S = 1 / D]: ratio of current I and

Voltage drop U

I distance of the electrodes or length of the flow path [m] A cross section of the conducting current [m ² ]

K = l / A cell constant of the LF sensor [1 / m].

The slope of the conductivity (in the mathematical sense: the derivative) decreases with increasing concentration C, due to the weakened mobility of the ions. This can be experimentally measured in the molar conductivity

be detected.

The calculation model is based on the simplification that the molar conductivity of the individual electrolytes / salts is regarded as only dependent on the total electrolyte concentration Q, and from this an expected value for the conductivity of the dialysis fluid is determined. The consideration of the interdependencies between the individual components is not necessary and is therefore not calculated in the calculation model. The salt strength Q can thus be calculated in the calculation model as the sum of the molar concentrations of all salts. The unit is mol / liter. The salt strength Q can be represented in the following formula for an exemplary dialysis fluid.

Q (C _a ci C _NaBic + C _{Na Coc} + C _KC1 + C _CaC1 + C _{M C1} + C _NaAc ) / 1000

where C indicates the molar concentrations of the respective salts NaCl, NaBic, KCl, CaCl, MgCl, NasCit, NaAc.

After a few transformations, the simplified equation is obtained.

In the calculation model, the calculation of the molar conductivity L of the individual salts is based on the following equation: where: i = NaCl, KCl, CaC, MgCh, NaAc, NasCit, NaBic, glucose.

The parameters a _x , i can be found in the literature, for example from the following publication: "EQUIVALENT CONDUCTIVITY OF ELECTROLYTES IN AQUEOUS SOLUTION" and "ELECTRICAL CONDUCTIVITY OF AQUEOUS SOLUTIONS" in CRC Handbook of Chemistry and Physics, Internet Version 2007, (87th Edition ), David R. Lide, ed., Taylor and Francis, Boca Raton, FL.

The distributions of the conductivity of the salts are calculated as follows:

KNaCI = ANSCI * CNSCI [uS / cm]

Kka = Lka * CKCI [uS / cm]

The expected value CDü.exp for the conductivity in the result data set is calculated as the sum of all conductivity distributions, with: In a preferred embodiment of the invention, the component parameters comprise a glucose concentration. This may represent the molar concentration of glucose in the A component. According to another advantageous embodiment of the invention, the method or method of operation for a mixing device additionally comprises (after calculating the result data set) the following method step:

- Generate a control command based on the generated

Result data set for driving a mixing device for

Mixing the dialysis fluid for a dialysis machine according to a recipe.

According to another advantageous embodiment of the invention, the

Generating the control command executed only when an acknowledgment signal (by the user) has been detected, representing that the recipe has been confirmed.

For the person skilled in the art, it is on the Fland that the calculated result data set can be subjected to an automatic check. The calculated result data set may be e.g. be checked for compliance with normal standards. Furthermore, a plausibility check of the calculated

Result data set to be executed.

In another aspect, the invention relates to a computing unit for calculating a result data set for establishing a dialysis fluid from a plurality of components on the basis of a calculation model for the conductivity of the dialysis fluid, comprising:

- a read-in interface which is used to read in a mixing ratio

Dataset is determined, which represents a mixing ratio of at least one A-component (A-concentrate) and - optionally a B-component (B-concentrate) and - another (or possibly third) component (RO-water);

- A component interface used to capture component

Parameter is determined, comprising a first substance concentration parameter, the concentration of a substance and in particular the concentration of salt in the A component

and a second substance concentration parameter representing the Concentration of the substance and in particular represents the concentration of salt in the B component;

A processor used to calculate the result data set for

Composition of the dialysis fluid, comprising an indication of the substance resulting in the mixture to be generated.

Concentrations in the dialysis fluid and an expected value for the conductivity of the dialysis fluid based on a

Calculation model.

The arithmetic unit may include an output unit (e.g., graphic Ul). The arithmetic unit may additionally include:

A user interface via which an actuation signal can be received; and or

- A memory for storing confirmed recipes.

According to another preferred embodiment of the invention, the

Computing unit additionally include:

- A sensor interface for receiving sensor signals for the measured conductivity of the dialysis fluid;

and wherein the arithmetic unit is designed to measure the measured conductivity of the dialysis fluid with DESIRED specifications, e.g. from the recipe and / or with the calculated expectation value for the conductivity to match in order to output an error message if there is no match. If they match, a validation signal may be output that initiates the delivery of dialysis fluid to the dialysis machine. In a further aspect, the invention relates to a mixing device for producing a dialysis fluid from a plurality of components with:

An interface to a computing unit as described above;

An A connection to a first container to provide an A component; Optional: a B-connection to a second container to provide a B-component;

A third connection to a third container for providing RO water;

- Mixing means for mixing the dialysis fluid in a mixing chamber of at least the A component, optionally the B component and RO water according to the specifications of one of the arithmetic unit

provided result data set.

The mixing device can be operated in different operating modes. Thus, a 1 MIX process can be used in which only the acid and salt containing A component is mixed with RO water. Likewise, a 2MIX method can be used in which, in addition to the A component, the

(In particular, no acid-containing) B component and RO water are mixed. Furthermore, a 3MIX process with an admixture of further individual components can be used.

In a further aspect, the invention relates to an operating method for such a mixing device, in which the mixing means for mixing the dialysis fluid are controlled with control commands, wherein the control commands from the

Result data set to be calculated. In the operating method, it is preferably automatically checked whether the components (or constituents) indicated in the formulation each have the

corresponding storage containers (e.g., in the form of canisters) for mixing have been connected to the mixing device or to the dialysis machine by comparing a component-identifying code at the respective storage container with a respective stored reference to agreement. This can advantageously be excluded errors that are based on a wrong choice of the concentrate bag.

In a further aspect, the invention relates to a dialysis machine with such a computing unit and / or with such a mixing device. The arithmetic unit is an electronic component. It can be designed in hardware and / or software and serves to calculate a result data set for the composition of the dialysis fluid with an expected value for the conductivity. Above and below, the invention is described for a dialysis machine, for example a hemodialysis machine or a peritoneal dialysis machine. However, it will be apparent to those skilled in the art that the invention can be equally applied or applied to other medical, computer controlled, or fluid management or blood treatment equipment that mixes concentrates in a particular mixing ratio

Dialysis fluid must be supplied.

The dialysis fluid is a dialysis solution that typically contains solutes, such as:

- electrolytes Na, K, Mg, Ca to maintain an acceptable electrolyte balance of the patient;

- Buffers (for example bicarbonate, acetate, lactate ...)

- glucose (or other osmotic agents), as an osmotic agent in peritoneal dialysis or to maintain blood sugar levels during hemodialysis;

- Acids or salts of acids (for example, HCl or CI, acetic acid

Citric acid ...), which may contribute to the neutralization of basic dialysis dialysis solutions or present as counter-ions in the electrochemical equilibrium.

The recipe is a confirmed result record. As a recipe, therefore, only those component mixtures for the dialysis fluid are stored in the system or memory, the predefined target specification, e.g. Observe the limits and limits required for dialysis.

Another task solution is a computer program product that is loaded or loadable into a memory of a computer or a dialysis machine with a computer program for carrying out the method described in more detail above, when the computer program is executed on the computer or the dialysis machine.

A further task solution provides a computer program for carrying out all method steps of the method described in more detail above, when the computer program is executed on a computer, an electronic or medical device. It is also possible that the computer program is stored on a readable for the computer or the electronic or medical device medium. In the following detailed description of the figures, non-limiting exemplary embodiments with their features and further advantages will be discussed with reference to the drawing.

Brief description of the figures

Fig. 1 shows a schematic representation of a dialysis machine with a

Mixing device and a separate computing unit and the exemplified containers for the components to be mixed according to an advantageous embodiment of the invention.

Fig. 2 is an alternative embodiment of a dialysis machine with integrated

Containers and integrated mixing device with an integrated computing unit.

3 shows a schematic representation of a computing unit and the read and output signals or data sets according to a further exemplary embodiment of the invention.

4 is an exemplary schematic diagram of a

Verification procedure for testing mixed dialysis fluid based on sensor-measured conductivity and related controls.

5 is a flowchart of a method according to an advantageous one

Embodiment of the invention. Detailed description of the figures

In the following the invention will be described in more detail by means of embodiments in connection with the figures. Fig. 1 shows schematically a dialysis machine or a dialysis machine DG with other modules. For dialysis treatment, the dialysis machine DG must be supplied with a dialysis fluid df. The dialysis fluid df is mixed from several concentrates or components according to a predetermined or user-defined formulation. The components are usually provided in separate containers 1A, 1B, 1C.

The dialysis fluid df necessary for the extracorporeal blood treatment can - as shown in FIG. 1 - be mixed by a separate mixing device M. Fierstellen the dialysis fluid df can be prepared by mixing (wet / dry) concentrates (acidic A component, basic B component) with RO water, the i.d.R. is provided by a central RO water treatment within the dialysis station, take place after a certain prescribed mixing ratio.

The dialysis fluid df is an aqueous solution of electrolytes, buffers and possibly glucose. Among other things, the kidney of patients on dialysis is no longer able to excrete acid via the urine, which increases the risk of latent acidosis. In order to balance the acid / base balance, the dialysis fluid should assume a physiological PH value that corresponds to that of a healthy person. For this purpose, acidic and basic components (A and B component or concentrate) are mixed together with RO water. The basic component often used is sodium bicarbonate powder (NaHCO 3) dissolved in RO water. The mixture with RO water produces sodium and bicarbonate in the finished dialysis fluid. Bicarbonate acts as a pH buffer in the patient's blood. During dialysis, bicarbonate diffuses across the membrane of the dialysis filter into the patient's blood and "buffers" the desired pH in the blood, ie keeps it stable at a level. The present invention is based on the monitoring of the dialysis fluid composition, in particular on the monitoring of the conductivity by comparison with an expected value.

Previously, to determine the conductivity of the mixed dialysis fluid, the values for the volume fractions of concentrates A (11) and B (eg 1,831) and RO water (eg 341) given on the concentrate containers were entered into the dialysis machine. In addition, the substance concentrations of the electrolytes (Na, K, Ca, Mg, acetate, citrate, bicarbonate, glucose, etc.) and acids (acetic acid or hydrochloric acid) of the ready-mixed dialysis fluid df, which result from this specific mixing ratio, were entered. This information is also given on the concentrate containers or containers 1A, 1B.

The substance concentrations given on the concentrate containers 1 A, 1 B in this case relate to the stated mixing ratio of the components A, B and RO water. As a rule, this mixing ratio is not changed. However, there is the possibility of changing the values for the sodium concentration and for the bicarbonate concentration, for example in order to achieve a specific therapeutic goal (adjustment of the sodium content in the patient's blood).

A change of said values automatically results in a change of the aforementioned mixing ratio. The electrolyte concentrations indicated on the concentrate containers 1A, 1B therefore no longer correspond to reality in this case. The previous method is thus error-prone, especially if the substance concentrations are changed by the user. This has the technical background that the sodium and the acid concentration of a mutual dependence are subject, because their concentration changes by chemical reaction with each other in the other concentrate containers substances.

The present invention proposes to solve the above-described problem in previous systems that, instead of the electrolyte concentrations, the concentrations of the salts (NaCl, Kcl etc.) and the acids (acetic acid, citric acid) of the concentrates (in unmixed state) are entered into the dialysis machine , By default, these values must always be completely determined by the manufacturers of the concentrate Containers 1A, 1B are provided. The values can either be entered manually or automatically by the user (eg via correspondingly applied identification codes which are read in and automatically assigned to the respective ingredient by means of an electronically stored table). From these data, according to the invention, the electrolyte or substance concentrations in the ready-mixed dialysis fluid df and the resulting expectation value for the conductivity of the finished dialysis fluid df are calculated using a mathematical-chemical calculation model.

As shown in Fig. 1, the mixing device M can be controlled by control commands sb, which receives them from a - in this embodiment, separate - arithmetic unit R. The control commands control mixing means of the mixing device and are calculated based on the result data set. The mixing device is used for mixing and preparation of the dialysis fluid df, which is transmitted to the dialysis machine DG. The different containers for the components for mixing the dialysis fluid df can be provided with identification codes. Thus, indirectly, the A-component contained in the A-container 1A is identified with the identification code 1 Ai. The respective identification code thus indicates in a mathematically unambiguous manner the container and indirectly the ingredient and / or the substance concentration contained therein (in particular salt concentration). The B container 1 B with the B component or with the B concentrate is eg provided with the identification code 1 Bi. The identification code may be a digital code (bar code, QR code) or any other identifying tag (NFC tag) deposited on the container. The assignment between code and container is stored in the arithmetic unit R. In this way, a check can be made on the arithmetic unit R as to whether the corresponding, correct containers are also connected or used for mixing for the respectively prescribed formulation for the dialysis fluid df. This check will be explained in more detail below in connection with FIG. The architecture of the system with separate modules M, R, DG, shown by way of example in FIG. 1, can alternatively also be varied. Fig. 2 shows an alternative embodiment of the invention, in which the dialyzing fluid df is mixed by the dialysis machine DG itself. In this example, the dialysis machine DG comprises the above-mentioned modules of the mixing device M with the integrated computing unit R. Also included are the chambers or containers 1A, 1B, 1C, 1D for the individual concentrates for mixing the dialysis fluid df. In this example, 4 components are used. The number of components is variable. Usually, 3 components (2 concentrates with RO water) are mixed. For a person skilled in the art, it is in the Flanders that other variations of the architecture are within the scope of this invention. Thus, for example, certain modules can be connected as separate modules via a corresponding connection, such as the containers, for example, can be provided as mobile units and connected to the dialysis machine DG via corresponding hose connections.

3 shows the arithmetic unit R with further details on the basis of a further exemplary embodiment. The arithmetic unit R comprises a processor P as

Calculation unit for the execution of calculations. The processor P is in data exchange with a memory MEM, in which the calculation model BM is stored and with a further memory, which may be formed as a database DB. A large number of confirmed recipes are stored in the database DB. The database DB and / or the memory MEM can in alternative

Embodiment also be outsourced so that the arithmetic unit can be made slimmer (smaller). The arithmetic unit R further comprises different interfaces: An input interface 31 for reading in the mixture ratio data set 311, a component interface 32 for detecting component parameters, in particular for detecting a first one

Concentration parameter 322-1 and for detecting a second

Concentration parameter 322-2. Both concentration parameters relate to the concentrates from the containers 1A, 1B (and possibly other containers or components). The concentration parameters 322-1, 322-2 preferably comprise a salt concentration in the respective component. In particular, they do not relate to the dialysis fluid df to be admixed, as was provided in the prior art. The information necessary for the concentrate parameters can all be taken from the information on the containers or they can - as explained above - also be recorded automatically. The acquired and read data are transmitted to the processor P.

The processor P is used to calculate a result data set 331. The result data set 331 can first on a user interface Ul for

Confirmation be issued by the user and then output via an interface 33 with control commands for implementation on the mixing device M to this. The result data set 331 is used to specify the composition of the dialysis fluid df to be mixed. The result data set 331 comprises an indication of substance concentrations, in particular to electrolyte and salt concentrations of the dialysis fluid df to be admixed and an expected value for the conductivity of the liquid df to be admixed. The calculation of the processor P is based on the calculation model BM. The result data set 331 is output on the user interface U1, which can be designed as a graphical user interface. This allows the user to confirm the result data set 331 with an acknowledgment signal 34. This takes place, in particular, when the resulting substance concentrations in the result data set 331 are in a normal range for dialysis. Only when an acknowledgment signal is input is the respective mixture ratio data record accepted as allowable formulation for the dialysis fluid df and can be stored in the database DB. Otherwise, the user is prompted to make another input and / or an error message is displayed on the interface U1 with further instructions. The result data set 331 is then transmitted to the mixing device M for mixing the dialysis fluid df. The result data set is here enriched with control commands sb, which allow the mixing device to be controlled in such a way that the stored recipe is obtained, which is then provided to the dialysis machine DG.

As input variables for the automatic calculation method, in addition to the mixing ratio data set 311 and the component parameters 322-1, 322-2,... 322-n (depending on the number of components to be mixed), an indication of the

Include volumes in which the amounts of salt are dissolved. It is beyond that possible to record further meta-data as input variables (time stamp, database, etc.).

The invention proposes a specific menu guide that instructs the user to make the necessary and necessary for the calculation step by step inputs. Through appropriate masks on a screen surface, it is passed through an input menu. This reduces the risk of errors. After entering the data required for the calculation, it is automatically executed to provide the result data set 331 (particularly on the user interface).

If the arithmetic unit R is used for monitoring the mixing device M, the arithmetic unit R comprises, in addition to the aforementioned interfaces, a further interface 34 for detecting sensor signals for the measured conductivity 41 of the dialysis fluid produced by the mixing device. For this purpose, the arithmetic unit R receives the signals from at least one (preferably several) conductivity sensor (s) S via the interface 34 and forwards the conductivity signals 41 to the processor P for checking to ensure that the conductivity is within the intended range was defined by the recipe and / or in the result data set 331. Thus, the ongoing operation of a mixing device M can be monitored, which increases the overall safety of the dialysis machine DG. 4 shows the use of the arithmetic unit R for checking a ready-mixed dialysis fluid df for compliance with the specifications of the formulation and, in particular, for checking the substance composition. For this purpose, the sensors S for measuring the conductivity of the dialysis fluid df are preferably provided at different positions. In a preferred embodiment of the invention, a plurality of sensors S for redundant detection of the conductivity at different positions (eg at the mixing device M, in the connection between mixing device M and dialysis machine DG and / or on the dialysis machine DG itself) may be provided. The sensors S send their measurement result with the currently measured conductivity 41 as a signal to the computing unit R for checking. This receives the conductivity values via the interface 34 (not shown in Fig. 4). In the arithmetic unit R, target specifications and / or the recipe with the result data set 331 are stored. If there is a match, the mixed Dialysis fluid df as planned, transmitted to the dialysis machine DG without further message. If the currently measured conductivity 41 does not correspond to the specifications or the expected value, an error message 43 is output. The error message 43 can be output on the mixing device (represented in FIG. 4 by the arrow to the mixing device M) and / or on the dialysis machine DG and / or on a central control and monitoring unit in order to initiate corrective measures. The latter is represented in FIG. 4 by the downwardly pointing arrow with the error message 43. In principle, the control unit sb is provided by the arithmetic unit R in order to operate and control the mixing device in accordance with the specifications of the result data set 331. In this case, the arithmetic unit R additionally assumes the task of controlling and regulating the mixing device M.

Fig. 5 is a flow chart of an input method for concentrate parameters. After the start of the method, the information about the intended mixing ratio is read in step 51. In particular, the mixture ratio data set is read in. This can be done by means of a user input on a user interface (eg the surface of the computing unit R). In this embodiment, the information is user-defined. Alternatively, it is also possible for the above-mentioned data to be predefined and read in from the memory via the interface 31. In step 52, the component parameters are detected, that is, the first salt concentration parameter 322-1 and the second salt concentration parameter 322-2. In this embodiment, the first and second substance concentration parameters are referred to as salt concentration parameters. The information can either be acquired via the user interface U1 in a first embodiment of the invention. Alternatively, they can be detected automatically in a second embodiment of the invention via the interface 32, which is for this purpose in data exchange with an electronic indication on the container 1A, 1 B. Thus, for example, the identification code 1 Ai, 1 Bi next to Identification notice still another data field, in which the respective salt concentration parameter 322-1 and 322-2 of the respective components is represented. The further data field can also be provided separately, for example as a QR code on the container of the manufacturer of the concentrate. Alternatively, in the arithmetic unit R an assignment table be deposited, in which the component parameters are stored for the respective identification code of the concentrate or the component. Through an access (eg look-up table) to this table, the component parameters can thus also be detected automatically in this third variant of step 52. After the data input, therefore, the resulting dialysis fluid parameters are calculated. For each of the concentrates a tabular listing can be displayed in a separate screen mask, which contains the resulting electrolytes and the conductivity to the respective concentrate (with a uniquely assigned ID number). This list may be subject to a review, in particular an audit for compliance with predefined admissibility values or ranges.

In step 53, the result data set 331 is calculated by accessing the calculation model BM. In step 54 it is checked whether the resulting concentrations are within the predefinable standard range for dialysis. If no, a warning message is issued in step 56. If necessary, a hint can be issued on the surface U1 informing the user about the wrong formulation and giving further indications as to which values were decisive for the exceeding of the limit value. If the test in step 54 is successful, the recipe can be confirmed in step 56. Only confirmed recipes can subsequently be stored in the memory DB in step 57. The process then ends or is executed repeatedly.

An operating method for a mixing device that can be integrated in a dialysis machine DG or connected as a separate device of the dialysis machine DG, for example, could have the following sequence: In a service menu, a new formulation proposal for a dialysis fluid is entered, in which the mixing ratio (mixing ratio data set : A, B concentrate, RO water) is selected and the salt and, if necessary, the glucose concentration and glucose concentration (glucose is an optional ingredient) is entered as a component parameter in the menu. This recipe proposal can already be assigned an ID number for the purpose of identification. The formulation proposal is hereafter examined by using the stored calculation model, the resulting substance concentrations of the prepared according to the recipe proposal dialysis fluid are determined and displayed in a screen. Atypical values are highlighted (eg yellow background). It is also possible to carry out automatic test methods for the intended recipe, for example checking for compliance with standard ranges and / or predefinable limit values. The operator can now either discard this recipe or add it to the recipe directory of the dialysis machine where formulas can be selected. At a later stage, the mixing device can be monitored for compliance with the formulation determined by the above procedure. For this purpose, the arithmetic unit R or the dialysis machine DG with the arithmetic unit R is configured in such a way that the internally or externally determined recipe and in particular the calculated result data set is used to appropriately prepare and monitor the dialysis fluid by suitable means. In this case, the dialysis machine has devices or connections for connecting the concentrate container and the RO water, and means for conveying and mixing of the components according to the selected recipe (dosing pumps, mixing chambers, etc., not shown in the figures), and conductivity sensors S preferably in a fresh dialysate liquid line for monitoring the conductivity with respect to the expected value of the conductivity calculated in the result data set. It goes without saying for a person skilled in the art that the temperature of the dialysis fluid can be regulated to a physiologically sensible value and the conductivity measurement is temperature-compensated. The solution proposed here has the technically advantageous effect that the concentrate parameters 322-1, 322-2 are detected redundantly. This has the advantage that errors can be detected by information on the

Concentrate containers 1A, 1B result, which refer to other mixing ratios (different from the recipe). Errors may arise, for example, in that two different details are printed on the concentrate bag that contradict each other. For example, the electrolyte concentrations given in the first field result in a dilution of the A concentrate by a factor of 1:34. In fact, however, the A concentrate is diluted by a factor of 1: 36.83 in dialysis fluid preparation (as indicated in the second panel). Vorteilhaferweise can thus be detected automatically if the specified electrolyte concentrations refer to a different dilution or mixing ratio than the recipe corresponds.

Furthermore, incorrectly printed values can also be recognized in the lists of ingredients on the concentrate bags 1A, 1B. If e.g. the acetate concentration is given in a first list on the pouch 1A at 3.0mmol / L and in a second list of another pouch 1A '0.3mmol / L, although in both A concentrates the same amount of acetic acid (H - Acetate) is weighed, this source of error can be detected automatically.

In summary, an important advantageous effect of the approach presented here is that the calculation model for determining the conductivity of the dialysis fluid mixed from concentrates with a plurality of electrolytic constituents and RO water for determining the molar conductivity takes into account only the total concentration of all electrolytic constituents; this is also referred to as salt strength Q. Dependencies between the individual electrolytic components are not considered. Tests have shown that this simplification allows the conductivity of the resulting dialysis fluid to be modeled with sufficient accuracy and thus a qualitatively good result can be provided.

Finally, it should be noted that the description of the invention and the embodiments are not to be understood as limiting in terms of a particular physical realization of the invention. All of the features explained and shown in connection with individual embodiments of the invention may be provided in different combinations in the article according to the invention in order to simultaneously realize their advantageous effects. Thus, it is also within the scope of the invention alternatively or cumulatively to provide other operating or control elements of the arithmetic unit R to the graphical user interface - eg for the input of the confirmation signal 34. The mixing device M and the arithmetic unit R are usually integrated in the dialysis machine DG. However, it is particularly apparent to one skilled in the art that Other architectures with separate units in communication can also be applied without departing from the inventive idea. Otherwise, the components of the medical system can be implemented distributed over several physical products. The scope of the present invention is given by the claims and is not limited by the features illustrated in the specification or shown in the figures.

REFERENCE NUMBERS

DG dialysis machine

1A A concentrate container

1 B B concentrate container

1 C third container, especially for RO water

1 Ai identification code for A concentrate container

1 Bi Identification Code for B Concentrate Container M Mixing Device

R arithmetic unit

sb control command

P processor

Ul (graphical) user interface

DB memory for storing confirmed recipes

MEM memory for storing the calculation model and / or data

31 read-in interface

32 component interface

33 result data interface

34 Interface for reading the conductivity measured by sensors 331 Result data set

31 1 mixing ratio data set

322-1 first concentration parameter

322-2 second concentration parameter

BM calculation model

34 confirmation signal

S Sensor for measuring conductivity

41 measured conductivity 42 validation signal

43 Error message df dialysis fluid

51 Reading the mixture ratio data set

52 Acquire the component parameters

53 Calculating the Result Record

54 Check if resulting concentrations in the standard range 56 Confirm as a recipe

57 Saving the recipe

Claims

1. Method for calculating a _" result data set (331) for

Composition of a mixture of several components

Dialysis fluid (df) based on a calculation model (BM) for the conductivity of the dialysis fluid, with the following process steps:

- Reading (51) a mixture ratio data set (311), the one

Mixing ratio of at least one A-component - and

optionally a B-component and a third component;

- acquiring (52) component parameters comprising a first substance concentration parameter (322-1) representing the concentration of a substance in the A component and optionally a second substance concentration parameter (322-2) representing the concentration of the substance Substance in the B component represents;

- calculating (53) the result data set (331) for the resulting

Composition of the dialysis fluid (df) comprising an indication of substance concentrations in the dialysis fluid and a

Expected value for the conductivity of the dialysis fluid based on the calculation model (BM).

2. The method of claim 1, wherein the method comprises the step of:

- Check (54) if the substance concentrations are calculated from the calculated

Result data set (331) each lie in a predefined normal range and, if so: Save the mixing ratio record (311) as a confirmed recipe for the dialysis fluid.

3. The method according to the immediately preceding claim, wherein the

In the case of a successful check, the read-in mixture ratio record (311) acts as a recipe, whereby the recipe is uniquely assigned an ID number.

4. The method according to any one of the preceding claims, wherein the method additionally comprises the following method step:

- Display of substance concentrations and / or - In case of unsuccessful testing of substance concentrations for compliance with standard ranges: Issue of a warning message.

A method according to any one of the preceding claims, wherein the concentration of the substance is a salt concentration and wherein the calculation model (BM) is based on a salt strength, the salt strength being a measure of the sum of all molar concentrations of all salts , and wherein in the calculation model (BM) the conductivity with the

Salt strength is correlated.

6. The method according to any one of the preceding claims, wherein the

Component parameters include a glucose concentration.

7. The method according to the immediately preceding claim, wherein the

Generating the control command is executed only when a confirmation signal has been detected, representing that the recipe has been confirmed.

8. arithmetic unit (R) for calculating a result data set (331) for

Production of a dialysis fluid (df) from several components on the basis of a calculation model (BM) for the conductivity of the dialysis fluid (df), with:

- A read-in interface (31), which is used to read in a

Mixing ratio record (311) is determined, the one

Mixing ratio of at least one A component and a B component and a third component represented;

- A component interface (32) used to capture

Component parameters, comprising a first substance concentration parameter (322-1) representing the concentration of a substance in the A component and a second substance concentration parameter (322-2) indicating the concentration of the substance in the B component. Component represents;

A processor (P) used to calculate the result data set (331) for the resulting composition of the data to be generated

Dialysis fluid (df), comprising an indication of substance Concentrations in the dialysis fluid and an expected value for the conductivity of the dialysis fluid based on a

Calculation model (BM).

9. arithmetic unit (R) according to the immediately preceding to the

Computing unit directed claim, which additionally comprises:

A user interface (UI) via which an actuation signal can be received; and or

- A memory (DB) for storing confirmed formulations.

10. arithmetic unit (R) according to one of the immediately preceding to the

Computing unit directed claims, which additionally comprises:

- A sensor interface (34) for receiving sensor signals for

measured conductivity (41) of the dialysis fluid (df); and wherein the arithmetic unit (R) is adapted to compare the measured conductivity (41) of the dialysis fluid (df) with target specifications and / or with the calculated expectation value to match in order to output an error message if there is no match.

11. Mixing device (M) for producing a dialysis fluid (df) from

several components for a dialysis machine (DG), with:

- An electronic interface to a computing unit (R) according to one of the immediately preceding related to the arithmetic unit

Claims;

An A connection to a first container (1A) for providing an A component;

- Optional: a B-connection to a second container (1 B)

Providing a B component;

- A third connection to a third container (1 C) for the provision of RO water;

Mixing means for mixing the dialysis fluid (df) in one

Mixing chamber of at least the A component, optionally the B Component, and RO water according to the specifications of a provided by the arithmetic unit (R) result data set (331).

12. Operating method for operating a mixing device (M) according to the

immediately preceding claim, wherein the mixing means for mixing the dialysis fluid with control commands (sb) are controlled, the

Control commands (sb) are calculated from the result data set (331).

13. Operating procedure after immediately preceding to

Operating method directed to monitoring the

Mixing device (M) and the mixed dialysis fluid (df) is used by the current conductivity of the produced

Dialysis fluid (df) is measured and compared with target specifications and / or the calculated expected value, to be absent

Match an error message.

14. Operating method according to the immediately preceding claim, wherein it is automatically checked whether for the indexed in the result data set (331) and / or in a recipe ingredients respectively the corresponding containers (1A, 1 B, 1 C, 1 D, ... ) have been connected to the mixing device (M) for mixing by comparing an ingredient-identifying code on the respective container (1A, 1B, 1C, 1D, ..) with a respective stored reference to match.

15. Dialysis machine (DG) with a computing unit (R) according to the

preceding claims directed to the arithmetic unit.

16. dialysis machine (DG) with a mixing device (M) according to the preceding related to the mixing device claim.