CN111757763A

CN111757763A - Model-based mixture of dialysis liquids for dialysis devices

Info

Publication number: CN111757763A
Application number: CN201980014709.8A
Authority: CN
Inventors: 皮亚·丹尼尔; 阿尔弗雷德·加格尔; 卡斯滕·米勒; 克里斯托夫·维克托
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: 2020-10-09
Also published as: WO2019162227A1; EP3755395A1; DE102018103845A1

Abstract

The invention relates to a method and a calculation unit (R) and a mixing device (M) for calculating a result data set (331) relating to the composition of a dialysis liquid (df) to be mixed by a plurality of components on the basis of a calculation model (BM) for the conductivity of the dialysis liquid, the method having the following method steps: -reading (51) a mix ratio data set (311) representing a mix ratio of at least one a-component and B-component and a third component; -detecting (52) composition parameters comprising a first substance concentration parameter, in particular representing the concentration of a salt in the a-composition, and a second substance concentration parameter, in particular representing the concentration of a salt in the B-composition; -calculating (53) a result data set (331) regarding the derived composition of the dialysis liquid, the result data set comprising a description of the concentration of the substance in the dialysis liquid and a description of the desired value of the conductivity of the dialysis liquid based on the calculation model (BM).

Description

Model-based mixture of dialysis liquids for dialysis devices

Technical Field

The invention relates to a monitored and model-based mixture of dialysis liquids for a dialysis apparatus. The invention relates in particular to a mixing device, a dialysis device having such a mixing device and a method for operating a mixing device.

Background

The dialysis device is a blood treatment device in which the fluid of the patient is supplied to a fluid treatment member via a fluid line, treated by the fluid treatment member and returned to the patient again via a fluid line which can be divided into an arterial branch and a venous branch. Examples of such blood treatment apparatuses are, in particular, hemodialysis apparatuses. Such a blood treatment device is the subject of DE 19849787C 1 of the applicant, the content of which is hereby fully incorporated into the disclosure of the present application.

Dialysis is a method for blood cleaning in patients with acute or chronic renal failure. In principle, a distinction is made in this case between methods with the aid of an extracorporeal blood circuit, such as hemodialysis, hemofiltration or hemodiafiltration, and peritoneal dialysis without the aid of an extracorporeal blood circuit.

In hemodialysis, blood is conducted in an extracorporeal blood circuit through a blood chamber of a dialyzer, which is separated from a dialysis liquid chamber by a semipermeable membrane. The dialysis fluid chamber is traversed by a dialysis fluid containing a specific concentration of blood electrolytes. Here, the substance concentration of blood electrolytes in the dialysis liquid corresponds to the concentration of blood electrolytes in the blood of a healthy person.

During treatment, the patient's blood and dialysis fluid are typically passed by both sides of the semi-permeable membrane in a counterflow with a preset flow rate. Substances which need to be excreted in urine diffuse across the membrane from the blood compartment into the compartment for the dialysis liquid, whereas electrolytes present in the blood and the dialysis liquid diffuse from the compartment of higher concentration to the compartment of lower concentration, respectively. If a pressure gradient is formed at the dialysis membrane from the blood side to the dialysate side, for example by a pump which extracts dialysate from the dialysate circuit downstream of the dialysis filter on the dialysate side, water is transferred from the patient's blood via the dialysis membrane into the dialysate circuit. The process, also known as ultrafiltration, results in the desired dehydration of the patient's blood.

In hemofiltration, ultrafiltrate is extracted from the patient's blood by applying a transmembrane pressure in the dialyzer without the dialysis fluid passing by the side of the membrane of the dialyzer opposite the patient's blood. Additionally, a sterile and pyrogen-free replacement solution can be added to the patient's blood. Depending on whether the substitution solution is added upstream or downstream of the dialyzer, it is referred to as pre-dilution or post-dilution. In hemofiltration, the substances are exchanged convectively.

Hemodiafiltration is a method that combines hemodialysis and hemofiltration. Not only does diffusive substance exchange between the patient's blood and the dialysis liquid take place via the semipermeable membrane of the dialyzer, but also the plasma water contained in the blood is filtered out by the pressure gradient at the membrane of the dialyzer.

Hemodialysis, hemofiltration and hemodiafiltration methods are generally performed by means of automatic hemodialysis apparatuses, such as those sold by the applicant.

Plasma separation is a blood treatment method in which patient blood is separated into plasma and its constituent parts (cells). The separated plasma is cleaned or replaced by a replacement solution, and the cleaned plasma or replacement solution is returned to the patient.

In peritoneal dialysis, the abdominal cavity of a patient is filled via a catheter guided through the abdominal wall with a dialysis liquid having a concentration gradient of blood substances, such as electrolytes (e.g. sodium, calcium and magnesium), relative to the body's own liquid. Via the Peritoneum (Peritoneum), which functions as a membrane, toxic substances present in the body pass from blood vessels running in the Peritoneum into the abdominal cavity. After a few hours, the dialysis fluid, which is now contaminated with toxic substances leaving the body, is replaced in the abdominal cavity of the patient. By the osmosis process, water in the patient's blood can be transferred via the peritoneum into the dialysis liquid, thereby dehydrating the patient.

The method for peritoneal dialysis is usually performed by means of an automated peritoneal dialysis apparatus, such as the one sold by the applicant.

The dialysis liquid for dialysis equipment is usually prepared by mixing at least two dialysis concentrates with RO water (reverse osmosis). To form the dialysis liquid, a water tank for RO water and containers for different concentrates or components can be used to prepare the dialysis liquid. The concentrate can be provided in solid and/or liquid form.

In a particular type of treatment, for example in "bicarbonate hemodialysis", two dialysis concentrates are usually used, which concentrates are diluted by RO water in a defined amount and mixed with one another to form a so-called dialysis liquid before the dialysis treatment. The concentrates are an acidic concentrate (component a) and a basic concentrate (component B). The alkaline concentrate is generally composed of a sodium bicarbonate solution of defined concentration. The acidic concentrate contains all the remaining components necessary for the dialysis treatment. This is in particular the electrolyte, i.e. sodium, potassium, calcium, magnesium, and the further constituents are chloride, acetate. The acidic concentrate can also include glucose.

In a first method for preparing a dialysis liquid, the mixing is carried out by means of a volumetric mixing method, in which water and concentrate are mixed with each other in a specific preset volumetric ratio.

A second method for preparing a dialysis liquid is the conductivity adjustment method, wherein the ratio of the water component and the concentrate component is adjusted such that a certain conductivity is set in the finished dialysis liquid, which conductivity is caused by the electrolyte or substance concentration in the finished dialysis liquid. This second method of conductivity adjustment is intended 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: the dialysis equipment must monitor the composition of the dialysis fluid for sodium and bicarbonate. The protection system must recognize defined deviations from preset desired values and protect the patient from danger.

In a conductivity-regulated dialysis apparatus, the conductivity of the dialysis liquid which has been mixed to completion is used as a measurement variable. A desired value of the conductivity with a preset desired value is calculated on the basis of the electrolyte concentration in the dialysis liquid. For this purpose, the device must know the electrolyte concentration.

In a dialysis device, the concentration of the individual electrolytes (Na, K, Ca, Mg, Cl, acetate, citrate, bicarbonate) and the concentration of other components (for example, possibly glucose) based on a predetermined recipe (mixed portion of RO water, a concentrate and B concentrate) is typically entered by the user in a service menu on the user interface of the device.

However, some devices allow for the modification or adjustment of the sodium carbonate and bicarbonate values specified. That is, if the user adjusts the values, the metered volumes of the a and B concentrates change due to this change, and thus the concentrations of all other electrolytes change. In order to be able to calculate the concentration automatically, the machine needs other concentration parameters, namely the acid concentration from the a-concentrate and the sodium concentration from the B-concentrate.

However, the latter two values are not in the list of inclusions given by the manufacturer of the concentrate. Hitherto, in the prior art, the acid concentration and the salt concentration are manually input by a user. For this reason, very specific expertise is required in order to be able to correctly determine the acid and salt concentrations. Further calculations are based on the manual input. Thus, this approach is susceptible to errors. This operation cannot be performed by a standard trained service technician.

Furthermore, the following error sources cannot be identified:

a) a value printed incorrectly in a list of contents on the concentrate container, an

b) The specification of the electrolyte concentrate relates to a dilution ratio different from that of the corresponding formulation.

Disclosure of Invention

Based on the systems known in the prior art for providing a mixed dialysis liquid, the invention therefore proposes the following objects: the mixing of the dialysis liquid is automated and improved while maintaining the feasibility of flexible changes in sodium and bicarbonate values. In particular, the composition of the dialysis fluid should be subjected to an automatic check. Furthermore, the mixing should be made so that the treatment as a whole is safer.

According to the invention, said object is achieved by a method, a computing unit, a mixing device and a dialysis machine according to the appended parallel claims.

In the following, the invention is described with the help of a solution according to the object of the method. Features, advantages, or alternative embodiments mentioned herein are equally applicable to other claimed subject matter, and vice versa. In other words, physical claims (which are, for example, directed to dialysis machines or apparatuses) can also be improved by means of 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, and vice versa.

The means proposed herein for achieving the object described hereinbefore relate to two aspects:

1. the first means (method) for calculating the ingredients (herein called components) for the dialysis liquid makes it possible to provide a correct mixing of the concentrate or component with the electrolyte concentration produced or desired to be obtained. For this purpose, a numerical calculation model based on simplified calculations should be based. The data thus calculated is provided as a result data set which approximately comprises a recipe with the desired value of the electrical conductivity of the produced dialysis liquid.

2. A second means (running method) for checking whether a previously sought recipe is also followed. It is therefore necessary here to monitor whether the mixture results follow the presets of the recipe previously sought. For this purpose, a sensor for measuring the electrical conductivity is provided, which compares the measured electrical conductivity with an expected value calculated from the result data set. The second method is performed temporally after the first method. Both methods solve the same problem, but can in principle be used independently of each other.

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

-reading a mix ratio data set representing the mix ratio of at least one a component (e.g. a concentrate, acidic) and optionally a B component (e.g. B concentrate, basic, salt only) and another (or second or third) component (RO water). Here, the ingredient is usually a concentrate or another content. If the mixing ratio data set is predefined, it can be read automatically from the memory via the interface. Alternatively, the mixing ratio data set may also be user-determined and input by the user via a user interface. Other components or ingredients can also be added to the dialysis fluid.

-detecting composition parameters comprising a first substance concentration parameter indicative of the concentration of the substance in the a-composition and a second substance concentration parameter indicative of the concentration of the substance in the B-composition. The ingredient parameters relate to the concentration in the individual ingredients or concentrates in the as yet unmixed state. The composition parameters are not particularly relevant for the concentration in the dialysis liquid to be mixed (mixing state). The composition parameters relate to the chemical specification of the components in the as yet unmixed state (raw state, e.g. as a concentrate).

Calculating a result data set relating to the resulting composition of the dialysis liquid (to be generated), in particular from the read mixing ratio data set and the detected component parameters, comprising a specification of the substance concentration (such as in particular the electrolyte concentration) in the dialysis liquid (to be generated) and a specification of the desired value of the electrical conductivity of the dialysis liquid (to be generated) based on a calculation model. The result data set relates to the mixing state of the dialysis fluid.

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

checking whether the substance concentrations from the calculated result data set are in each case in a predefined standard range, and if this is the case: the mixing ratio data set is stored as a validated recipe for the dialysis liquid.

The described embodiment has the following advantages: only validated recipes, i.e. recipes that meet a predefined standard range preset, can be stored in the system.

Typically, the a concentrate comprises salt and acid. The B concentrate contains only salt, i.e. no acid.

There are different dialysis methods which differ in terms of the amount and the concentrate or ingredient to be mixed. In current bicarbonate dialysis, three fluids are mixed: concentrate A, concentrate B and RO water. In acetate dialysis, only two liquids are mixed: concentrate a and reverse osmosis water. In acetate dialysis (mixing of the two components), the method described herein should be used as well. In the 3MIX method, four components or liquids are mixed: concentrate A, concentrate B, individualized concentrate and RO water. The proposal according to the invention described here is also used here.

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 (in particular a salt) in the different components in the unmixed state. Alternatively, for selected components, the acid concentration can also be detected.

According to a further preferred embodiment of the invention, in the event of a successful check, the read mixing ratio data set is used as a (validated) recipe, with an ID number or identification code being associated one-to-one with the recipe. Thereby, further calculations can be performed very efficiently.

According to a further advantageous embodiment of the invention, the method additionally comprises (after the calculation of the result data set) the following method steps:

display of the concentration of the substance (produced in the mixed state), and/or

-upon unsuccessful check that the resulting substance concentration follows the standard range: a warning notification is issued.

In a further preferred embodiment of the invention, the method for monitoring a mixing device and a dialysis liquid mixed by means of the mixing device is used in the following way: the current conductivity of the prepared dialysis liquid is measured and compared with an expected preset (in particular out of the recipe) and/or with a calculated expected value of the conductivity in order to issue an error report in the absence of consistency.

The substance concentration is in particular the salt concentration.

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

The computational model is used to predict the conductivity of the dialysis liquid produced as a solution comprising a plurality of different electrolytes. The calculated result data set can be determined with sufficient accuracy for dialysis.

In the calculation model, the molar conductivity of the electrolyte is therefore always calculated identically, irrespective of whether a mixture of multicomponent substances is present. The molar conductivity of the pure electrolyte 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 was achieved with the following coefficients:

wherein:

V_aindicates the metered volume [ mL ] of A concentrate in the corresponding A pump]

V_mixRepresents the total dialysis fluid volume [ mL ] per batch or mixing cycle]

The MIX ratio data set and the sum of all components of the mixture (e.g., in the 2MIX method: a concentrate, B concentrate, and RO water) are input. After the mixing ratio data set has been entered, the concentration of the respective salts contained in the dialysis liquid is calculated on a computer basis and automatically.

The dialysis liquid mixing ratio with respect to the solution of the a-concentrate can be mathematically expressed as follows:

x_mix＝1+x_b+x_RO

the concentration C of the dialysis liquid which can be deduced from the substance X in the component or concentrate A can be calculated by_x：

Wherein:

C_Xrepresents the dialysis fluid concentration of substance X;

mx represents the weighed mass of substance X;

V_arepresents a dissolved mass m_xVolume [ L ] of concentrate A of (2)]；

M_XRepresents the molar mass [ g/mmol ] of the substance X]；

x_mixThe solubility factor of the A concentrate is shown.

In the case that glucose should be added, the dialysis liquid concentration C is calculated in a manner derived from the a concentrate by_C6H12O6：

Wherein:

C_C6H12O6represents glucose C as an optional component₆H₁₂O₆Concentration of dialysis liquid [ g/L ]]，m_GIndicating the weighed mass of glucose

f_GIndicating the correction factor

f_G1.0 denotes the correction factor when weighing glucose hydrate, f_G1.1 represents a correction factor when glucose monohydrate was weighed.

The corresponding relationship applies to the solution of the B concentrate. Therefore, in the above formula, only the constituent part referring to the component a is replaced by "B".

The calculation model for calculating the desired value for the conductivity of the dialysis liquid to be produced is based on the following knowledge: if the substance dissolves in water, the chemical bonds between the electrolytes are partially or completely broken. The electrolyte then dissociates into positively charged ions and negatively charged ions. The mobile charge carriers carry charges in aqueous solution. The increased electrolyte concentration C generally increases the conductivity κ, which is defined as:

wherein:

g ═ I/U denotes conductivity [ S ═ 1/□ ]: current I vs. voltage drop

I represents the interval of electrons or the length of the flow path [ m ]

A represents the cross section [ m ] of the current conducting²]

K ═ I/a denotes the battery constant [1/m ] of the LF sensor.

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

The computational model is based on the following simplifications: the molar conductivity of the individual electrolytes/salts is regarded as being related only to the total electrolyte concentration Q and from this the expected value of the conductivity of the dialysis liquid is determined. The interdependencies between the components need not be considered and are not further calculated in the calculation model. Thus, the salt strength Q can be calculated in a calculation model as the sum of the molar concentrations of all salts. The unit is mol/l. For an exemplary dialysis fluid, the salt strength Q can be expressed in the following equation.

Wherein C indicates corresponding salt, namely NaCl, NaBic, KCl and CaCl₂、MgCl₂、Na₃Molar concentrations of Cit, NaAc.

After several transformations, the following simplified equation is obtained:

in the calculation model, the molar conductivity Λ of each salt_iIs based on the following equation:

wherein: i ═ NaCl, KCl, CaCl₂、MgCl₂、NaAc、Na₃Cit, NaBic and glucose.

The parameter a can be known in the literature_x,iFor example, from the following publications: "EQUIVALENT connectivity OF ELECTROLYTES IN AQUEOUS SOLUTIONs" and "electrolytic connectivity OF ELECTROLYTES SOLUTIONs" IN the handbook OF chemical and physical CRC, screen interconnection 2007 (87 th edition), edited by David R.Lide, Taylor and Francis, Boca Raton, FL.

The conductivity distribution of the salt is calculated as follows:

κ_NaCl＝Λ_NaCl*C_NaCl[uS/cm]

κ_KCl＝Λ_KCl*C_KCl[uS/cm]

κ_CaCl2＝Λ_CaCl2*C_CaCl2[uS/cm]

κ_MgCl2＝Λ_MgCl2*C_MgCl2[uS/cm]

κ_NaBiC＝Λ_NaBiC*C_NaBiC[uS/cm]

κ_NaAc＝Λ_NaAc*C_NaAc[uS/cm]

κ_Glucose＝Λ_Glucose*C_Glucose[uS/cm]

κ_Na3Cit＝Λ_Na3Cit*C_Na3Cit[uS/cm]

calculating an expected value CD for conductivity in a resulting data set_D,expAs the sum of all conductivity distributions, wherein:

in a preferred embodiment of the invention, the composition parameter comprises glucose concentration. The glucose concentration can represent the molar concentration of glucose in the a component.

According to a further advantageous embodiment of the invention, the method or operating method for the hybrid system additionally (after the calculation of the result data set) comprises the following method steps:

-generating control commands based on the generated result data set to operate the mixing device to mix the dialysis liquid for the dialysis machine according to the recipe.

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

It is obvious to the person skilled in the art that the calculated result data set can be subjected to an automatic check. In this case, it can be checked whether the calculated result data set complies with usual standard values, for example. Furthermore, a plausibility check of the calculated result data set can be performed.

In a further aspect, the invention relates to a calculation unit for calculating a result data set for preparing a dialysis liquid composed of a plurality of components on the basis of a calculation model for the conductivity of the dialysis liquid, having:

-a reading interface determined for reading a mix ratio data set representing a mix ratio of at least one a-component (a-concentrate) and-optionally a B-component (B-concentrate) and-another (or possibly a third) component (RO-water);

a component interface which determines a parameter for detecting a component, the component parameter comprising a first substance concentration parameter representing a concentration of a substance and in particular a concentration of a salt in the a component and a second substance concentration parameter representing a concentration of a substance and in particular a concentration of a salt in the B component;

-a processor determining a result data set for calculating a composition relating to the dialysis liquid, the result data set comprising: a description of the substance concentration in the dialysis fluid, which is obtained in the mixture to be produced, and a description of the desired value of the electrical conductivity of the dialysis fluid on the basis of the calculation model.

The computing unit can include an output unit (e.g., a graphical UI). The computing unit can additionally include:

-a user interface via which a confirmation signal can be received; andor or

-a memory for storing the confirmed recipe.

According to a further preferred embodiment of the invention, the computing unit can additionally comprise:

a sensor interface for receiving a sensor signal relating to the measured conductivity of the dialysis liquid; and wherein the calculation unit is designed to compare the measured conductivity of the dialysis liquid with a desired preset consistency, for example from a recipe, and/or to compare the measured conductivity of the dialysis liquid with a calculated desired value of the conductivity, in order to issue an error notification in the absence of a consistency. If the two signals are identical, a verification signal can be emitted, which initiates the delivery of the dialysis liquid to the dialysis machine.

In another aspect, the invention relates to a mixing device for preparing a dialysis liquid composed of a plurality of components, having:

-an interface to a computing unit, as described hereinbefore;

-an a-connection to a first container for providing an a-component;

-optionally: an a connection to a second storage container B for providing B ingredient;

-a third connection to a third vessel for providing RO water;

a mixing mechanism for mixing the dialysis fluid in the mixing chamber from at least the a-component, optionally the B-component and the RO water according to a preset of the result data set provided by the calculation unit.

The mixing device can be operated in different operating modes. It is therefore possible to use the 1MIX method in which only the a component containing acid and salt is mixed with RO water. Likewise, a 2MIX method can be used in which, in addition to the a component, the B component (particularly, not containing an acid) and RO water are mixed. Furthermore, a 3MIX method of mixing with other personalized ingredients can be used.

In a further aspect, the invention relates to an operating method for such a mixing device, in which method a mixing means for mixing the dialysis liquid is controlled by means of a control command, wherein the control command is calculated from a result data set.

Preferably, in the operating method, it is automatically checked that: for the components (or contents) indicated in the recipe, a corresponding reservoir (for example in the form of a tank) is connected for mixing to the mixing device or dialysis machine, respectively, or is used, by: the component identifiers on the respective storage containers are compared with the stored references for consistency. Thereby, the following errors can advantageously be excluded: the error is based on an erroneous selection of a 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 calculation unit is an electronic component. The calculation unit can be embodied in hardware and/or software and is used to calculate a result data set with desired values of the electrical conductivity with respect to the composition of the dialysis liquid.

In the above and in the following, the invention is described for a dialysis machine, for example a hemodialysis apparatus or a peritoneal dialysis apparatus. However, it is obvious to the person skilled in the art that the invention can also be applied or transferred to other medical-technical, computer-controlled devices or (fluid-management) machines or blood-treatment devices, which have to be supplied with dialysis liquid mixed in a specific mixing ratio of concentrates.

The dialysis liquid is a dialysis solution that typically contains dissolved substances, such as:

electrolytes Na, K, Mg, Ca in order to maintain acceptable electrolyte metabolism in the patient;

buffers (e.g. bicarbonate, acetate, lactate.)

Glucose (or other osmotic agent), as osmotic agent in peritoneal dialysis or for maintaining blood glucose levels during hemodialysis;

acids, or salts of acids (e.g. HCl or Cl, acetic acid, citric acid …), which may help to neutralize alkaline sub-dialysis solutions or be present as counter-ions in electrochemical equilibrium.

The recipe is a validated results data set. Thus, only the component mixtures for the dialysis fluid that follow predefined target presets, such as standard values and limit values required in the dialysis, are stored in the system or in the memory as a recipe.

Another object solution consists in a computer program product which is loaded or loadable into a memory of a computer or a dialysis device, having a computer program for performing the method described in detail above when the computer program is executed on the computer or on the dialysis device.

Another objective solution proposes a computer program for performing all the method steps of the method detailed above when said computer program is executed on a computer, an electronic or a medical device. In this case, it is also possible that the computer program is also stored on a medium that is readable by a computer or an electronic or medical device.

Drawings

In the following detailed description of the drawings, discussion of embodiments and features and other advantages thereof, which are not to be construed as limiting, is made in accordance with the accompanying drawings.

Fig. 1 shows a dialysis device according to an advantageous embodiment of the invention in an exemplary view, with a mixing device and a separate computing unit and an exemplary container for components to be mixed.

Fig. 2 shows an alternative embodiment of a dialysis system with an integrated container and an integrated mixing device and a computing unit integrated therein.

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

Fig. 4 is a schematic diagram of an exemplary embodiment of an examination process for examining the mixed dialysis liquid on the basis of the electrical conductivity measured in a sensory manner and the control associated therewith.

Fig. 5 is a flow chart of a method according to an advantageous embodiment of the invention.

Detailed Description

Hereinafter, the present invention is described in detail according to embodiments with reference to the accompanying drawings.

Fig. 1 schematically shows a dialysis machine or a dialysis apparatus DG with other modules. In order to carry out a dialysis treatment, the dialysis apparatus DG must be supplied with a dialysis liquid df. The dialysis liquid df is mixed from a plurality of concentrates or components according to a preset or user-defined recipe. Typically, the ingredients are provided in

separate containers

1A, 1B, 1C.

The dialysis liquid df required for the extracorporeal blood treatment can be mixed, as shown in fig. 1, by means of a separate mixing device M. The preparation of the dialysis liquid df can be achieved by mixing the (wet/dry) concentrates (acid a-component, alkaline B-component) with RO water according to a specific, defined mixing ratio, which is normally available for use by a central RO water treatment in the dialysis station.

The dialysis liquid df is an aqueous solution of electrolytes, buffers and optionally glucose. The kidneys of patients requiring dialysis are in particular no longer sufficient to be able to excrete acid via urine, thereby increasing the risk of potential acidosis. To balance the acid/base metabolism, the dialysis fluid should be at a physiological PH corresponding to a healthy person. For this purpose, the acidic and basic components (a and B components or concentrate) are mixed together with RO water. Sodium bicarbonate powder (NaHCO3) dissolved in RO water is commonly used as the alkaline component. Sodium and bicarbonate are produced in the finished dialysis fluid by mixing with RO water. Bicarbonate acts as a PH buffer in the blood of the patient. During dialysis, bicarbonate diffuses into the patient's blood via the membrane of the dialysis filter and "buffers" the desired PH in the blood, that is, keeps it stably at one value.

The invention proceeds from the monitoring of the composition of the dialysis fluid, in particular the monitoring of the conductivity by comparison with an expected value.

Hitherto, in order to determine the conductivity of the mixed dialysis liquid, the volume fractions for the concentrates a (e.g. 1l) and B (e.g. 1.831) and the values specified on the concentrate vessel for the RO water (e.g. 341) have been fed into the dialysis apparatus. Additionally, the substance concentrations of the electrolytes (Na, K, Ca, Mg, acetate, citrate, bicarbonate, glucose, etc.) and of the acid (acetic acid or hydrochloric acid) of the dialysis liquid df for which the mixing has been completed are fed, which are derived from the specific mixing ratio. These instructions are also given on the concentrate vessel or concentrate

container

1A, 1B.

In this case, the substance concentrations specified on the

concentrate vessels

1A, 1B relate to the given mixing ratio of the component A, B and RO water. Usually, the mixing ratio is not changed. However, there are possibilities: the values of the sodium concentration and the bicarbonate concentration are varied, for example, in order to achieve a specific therapeutic goal (setting the sodium content in the blood of a patient).

The change in value also automatically causes a change in the mixing ratio as described above. That is, in this case, the electrolyte concentrations specified on the

concentrate containers

1A, 1B no longer correspond to the fact. Thus, the methods to date are susceptible to error, especially when the substance concentration is changed by the user. This has the following technical background: the sodium concentration and the acid concentration are related to each other in that their concentrations change due to chemical reactions with the substances in the other concentrate vessels, respectively.

In order to solve the problems described above in previous systems, the invention proposes that instead of the electrolyte concentration, the concentrations of salts (NaCl, Kcl, etc.) and acids (acetic acid, citric acid) of the concentrate (in an unmixed state) are fed into the dialysis apparatus. The values must always be provided in their entirety by the manufacturer of the

concentrate vessel

1A, 1B, in a standardized manner. The value can be entered either manually by the user or automatically (for example via a correspondingly applied identification code which is read and automatically associated with the respective content by means of an electronically stored table). According to the invention, the electrolyte or substance concentration in the dialysis liquid df that has been mixed is calculated from the data using a mathematical-chemical calculation model and the expected value of the conductivity of the dialysis liquid df for the production derived therefrom.

As is illustrated in fig. 1, the mixing device M can be controlled by a control command sb, which it receives from the, in the present exemplary embodiment separate, computing unit R. The control commands control the mixing mechanism of the mixing device and are calculated based on the result data set. The mixing device serves to mix and prepare the dialysis liquid df, which is transferred to the dialysis device DG.

The different containers for mixing the components of the dialysis liquid df can be provided with identification codes. Therefore, the a component contained in the a container 1A is indirectly identified by the identification code 1 Ai. The respective identification code thus indicates the vessel in a mathematically one-to-one manner and indirectly the contents and/or the concentration of substances contained in the contents (in particular the salt concentration). The B container 1B with the B component or with the B concentrate is provided with, for example, an identification code 1 Bi. The identification code can be a digital code (barcode, QR code) or other identification tag (NFC tag) applied on the container. The correlation between the code and the container is stored in the calculation unit R. This enables the following checks to be performed on the computing unit R: for the respectively preset recipe for the dialysis liquid df, whether the respective correct container is also connected or used for mixing. The examination is explained in detail below in connection with fig. 5.

The architecture of the system shown in fig. 1 with the separate module M, R, DG can alternatively also be varied.

Fig. 2 shows an alternative embodiment of the invention, in which the dialysis liquid df is mixed by the dialysis apparatus DG itself. In the example described, dialysis device DG comprises the above-described modules of mixing device M with a computing unit R integrated therein. Also comprised are chambers or

containers

1A, 1B, 1C, 1D for mixing the respective concentrates of the dialysis liquid df. In the example, 4 ingredients were used. The number of components is variable. Typically, 3 ingredients (2 concentrates with RO water) are mixed. Other variations of the architecture will be apparent to those skilled in the art and are within the scope of the invention. Thus, for example, it is also possible to switch on a specific module as a separate module, for example a container, via a corresponding connection, which can be provided, for example, as a mobile unit and connected to the dialysis device DG via a corresponding hose connection.

Fig. 3 shows a calculation unit R according to another embodiment with further details. The calculation unit R includes a processor P as a calculator for performing the calculation. The processor P exchanges data with a memory MEM in which the calculation model BM is stored and with another memory that can be configured as a database DB. A large number of validated recipes are stored in the database DB. In an alternative embodiment, the database DB and/or the memory MEM can also be transferred out, so that the computing unit can be constructed more narrowly (small). The computing unit R furthermore comprises different interfaces: an input interface 31 for reading the mixing ratio data group 311; a component interface 32 for detecting a component parameter, in particular for detecting a first concentration parameter 322-1 and for detecting a second concentration parameter 322-2. These two concentration parameters relate to the concentrate coming out of the

containers

1A, 1B (and optionally other containers or ingredients). The concentration parameters 322-1, 322-2 preferably include the salt concentration in the respective ingredients. The concentration parameters are not particularly relevant for the dialysis liquid df to be mixed, as proposed in the prior art. The required specifications for the concentrate parameters can all be known from the specifications located on the container or the specifications can also be detected automatically, as already explained above. The detected and read data are forwarded to the processor P.

The processor P is arranged to calculate a result data set 331. The result data set 331 can first be output on the user interface UI for confirmation via the user and then be transmitted by means of control commands via the interface 33 to the mixing device M for execution on said mixing device. The result data set 331 is used to specify the composition of the dialysis liquid df to be mixed. The result data set 331 comprises a description of the substance concentrations of the dialysis liquid df to be mixed, in particular the electrolyte and salt concentrations, and a description of the desired values for the electrical conductivity of the liquid df to be mixed. The calculation of the processor P is based on the calculation model BM. The result data set 331 is transmitted on a user interface UI, which can be designed as a graphical user interface. Thus, the user has the following feasibility: the result data set 331 is validated by means of the validation signal 34. This occurs in particular when the resulting substance concentration in the result data set 331 is in the standard range for dialysis. Only when a confirmation signal is entered, the corresponding mixing ratio data set is suitable as a permissible recipe for the dialysis liquid df and can be stored in the database DB. Otherwise, the user would be required to make other inputs and/or send an error notification with other indications on the interface UI. The result data set 331 is then forwarded to the mixing device M for mixing the dialysis liquid df. The result data set is enriched here by means of control commands sb which allow the mixing device to be controlled in such a way that the stored formulation is obtained and then provided to the dialysis device DG.

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), a specification of the volume in which the salt is dissolved is included as input variables for the automatic calculation method. It is also possible to detect other metadata as input variables (time stamps, databases, etc.).

The invention proposes a dedicated menu guide that guides the user step by step through the necessary and required inputs for the calculation. The user is guided through the input menu by a corresponding mask on the screen surface. This reduces the risk of errors. After entering the data required for the calculation, the calculation is automatically performed to provide a result data set 331 (particularly on a user interface).

If the mixing device M is monitored using the calculation unit R, the calculation unit R comprises, in addition to the interfaces mentioned above, a further interface 34 for detecting a sensor signal for the measured conductivity 41 of the dialysis liquid produced by the mixing device. To this end, the calculation unit R receives signals from at least one (preferably a plurality of) conductivity sensors S via the interface 34 and passes the conductivity signal 41 to the processor P for checking in order to ensure that the conductivity is in the desired range that has been defined by the recipe and/or in the result data set 331. By this means, the continuous operation of the mixing apparatus M can be monitored, which generally improves the safety of the dialysis machine DG.

Fig. 4 shows the use of the calculation unit R for checking whether the dialysis liquid df that has completed mixing follows a preset of the recipe and, in particular, for checking the substance composition. For this purpose, sensors S for measuring the conductivity of the dialysis liquid df are preferably arranged at different positions. In a preferred embodiment of the invention, a plurality of sensors S can be provided in order to detect the conductivity redundantly at different locations (for example at mixing device M, in the connection between mixing device M and dialysis device DG and/or at the dialysis device DG itself). The sensor S sends its measurement result with the currently measured conductivity 41 as a signal to the calculation unit R for checking. The calculation unit receives the conductivity value via an interface 34 (not shown in fig. 4). In the computer unit R, the recipe is stored which is expected to be preset and/or has a result data set 331. When they match, the mixed dialysis liquid df is transferred to the dialysis equipment DG as planned, without further notification. If the currently measured conductivity 41 does not correspond to the preset or desired value, an error notification 43 is output. Error notification 43 can be issued at the mixing device (indicated in fig. 4 by an arrow toward mixing device M) and/or at dialysis device DG and/or at a central control and monitoring unit, in order to be able to take corrective action. The latter is indicated in fig. 4 by a downwardly pointing arrow with an error report 43. In principle, the control command sb is provided by the calculation unit R in order to operate and control the mixing device according to the presets of the result data set 331. In this case, the computing 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, a description of the mixing ratio to be obtained is read in step 51. In particular, the mixing ratio data set is read out. This can be performed by means of a user input on a user interface, e.g. a surface of the computing unit R. In the described embodiment, the description is user-defined. Alternatively, it is also possible to predefine the data mentioned above and to read them from the memory via the interface 31. In step 52, the composition parameters, i.e., the first salt concentration parameter 322-1 and the second salt concentration parameter 322-2, are detected. In the described 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 the user interface UI. Alternatively, in the second embodiment of the invention, the description can be detected automatically via an interface 32, which for this purpose exchanges data with the electronic description on the

containers

1A, 1B. Thus, in addition to the identification indication, the identification codes 1Ai, 1Bi can for example comprise a further data field in which the respective salt concentration parameters 322-1 and 322-2 of the respective component are represented. The further data field can also be separate, for example provided as a QR code on the container of the manufacturer of the concentrate. Alternatively, a correlation table can be stored in the calculation unit R, in which the ingredient parameters relating to the respective identification code of the concentrate or ingredient are stored. By accessing the table (e.g. a look-up table), it is thus possible to automatically detect the composition parameters as such in the third variant of step 52.

That is, after inputting the data, the resulting dialysis liquid parameters are calculated. For each of the concentrates, a list of table types can be displayed in the inherent screen mask, which list includes the produced electrolyte and conductivity (by means of the one-to-one assigned ID number) in relation to the respective concentrate. The list can be subjected to a check, in particular whether a predefined permissible value or permissible range is adhered to.

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 concentration is in a standard range that can be predefined for dialysis. If not, a warning notification is output in step 56. Optionally, an indication can also be sent on the interface UI informing the user of the recipe with the error, and giving further indications: which values are decisive for the exceeding of the limit values. If the check in step 54 is successful, the recipe can be validated in step 56. Subsequently, in step 57, only the confirmed recipe can be saved in the memory DB. Whereupon the method is ended or repeated.

The method for operating a hybrid device that can be integrated into the dialysis machine DG or connected as a separate device to the dialysis machine DG can have the following sequence, for example:

in the service menu, a new recipe proposal for the dialysis liquid is entered, in which recipe proposal the mixing ratio (mixing ratio data set: a concentrate, B concentrate, RO water) is selected and the salt and optionally the acid concentration and optionally the glucose concentration (glucose is an optional component) are entered into the menu as composition parameters. For identification purposes, it has also been possible to associate an ID number with the recipe proposal.

Thereafter, the recipe proposal is checked using the saved calculation model, wherein the resulting substance concentration of the dialysis fluid produced according to the recipe proposal is determined and displayed in a screen view. In this case, the atypical value is highlighted (e.g., with yellow as the base). It is also possible to carry out an automatic checking method for the recipe desired to be obtained, for example checking whether a standard range and/or a predefined limit value is/are adhered to. The operator can now either discard the formula or add it to the recipe catalog of the dialysis device, from which the formula can be selected.

In a subsequent phase it can be monitored whether the mixing device follows the recipe determined according to the method described above. For this purpose, the computing unit R or the dialysis device DG with the computing unit R is configured such that the internally or externally determined formulation and in particular the calculated result data set are used for the corresponding preparation and monitoring of the dialysis liquid by means of suitable means. In this case, the dialysis device has a device or connection for connecting the concentrate container and the RO water, as well as means for delivering and mixing the components according to the selected recipe (metering pumps, mixing chambers, etc., not shown in the figure), and a conductivity sensor S for monitoring the conductivity in terms of the desired value for the conductivity calculated in the result data set, preferably in the fresh dialysis liquid line. It is obvious to the person skilled in the art per se that the temperature of the dialysis liquid can be adjusted to a physiologically meaningful value and the conductivity measurement can be carried out temperature-compensated.

The solution proposed here has the following technically advantageous effects: the concentrate parameters 322-1, 322-2 are detected redundantly. This has the following advantages: errors caused by instructions on the

concentrate containers

1A, 1B relating to other mixing ratios than the formula) can be identified. An error may be generated, for example, by: two conflicting instructions are printed on the concentrate bag. Thus, for example, the electrolyte concentration specified in the first region results when the a concentrate is diluted by a factor of 1: 34. In practice, however, when preparing the dialysis liquid (according to the description in the second zone), the a-concentrate is mixed with a factor of 1: 36.83 and diluting. Advantageously, it is thus possible to automatically recognize: when the given electrolyte concentration relates to a different dilution ratio or mixing ratio than the dilution ratio or mixing ratio corresponding to the formulation.

In addition, also in the list of contents on the

concentrate bags

1A, 1B, wrongly printed values can be recognized. If, for example, the acetate concentration is stated in the first list on bag 1A as 3.0mmol/L and in the second list of the other bag 1A' as 0.3mmol/L, the source of the error can be automatically identified, although the same amount of acetic acid (H acetate) is weighed in both A concentrates.

In summary, one important advantageous effect of the approach presented here is: a computational model for determining the conductivity of a dialysis liquid mixed by a concentrate having multiple electrolyte components and RO water considers only the total concentration of all electrolyte components for determining the molar conductivity; this is also referred to as the salt strength Q. The correlation between the respective electrolyte components is not considered. Tests have shown that the conductivity of the dialysis liquid produced can be accurately modeled by this simplification, which in turn can provide qualitatively good results.

Finally, it should be pointed out that the description and embodiments of the invention in principle should not be understood as being limitative in the particular physical implementation of the invention. All the features illustrated and shown in connection with the various embodiments of the invention can be set forth in the subject matter according to the invention in different combinations in order to achieve their advantageous effects simultaneously. Thus, for example, it is also within the scope of the invention to provide, alternatively or cumulatively to the graphical user interface, further operating or control elements of the calculation unit R, for example for inputting a confirmation signal. The mixing device M and the calculation unit R are usually integrated in the dialysis device DG. However, it is particularly obvious to a person skilled in the art that other architectures with separate, ongoing data exchange units can equally be used without departing from the inventive idea. Differently, the components of the medical system can be implemented in a manner distributed over a plurality of physical products.

The scope of the invention is indicated by the claims and is not limited by the features set forth in the description or illustrated in the drawings.

Reference numerals

DG dialysis equipment

1A A concentrate container

1B B concentrate container

1C third vessel, especially for RO Water

1Ai identification code for A concentrate container

1Bi identification code for B concentrate container

M mixing device

R calculating unit

sb control commands

P processor

UI (graphical) user interface

DB memory for storing validated recipes

MEM memory for storing computational models and/or data

31 read interface

32 component interface

33 structured data interface

34 interface for reading the conductivity measured by the sensor

331 result data set

311 mix ratio data set

322-1 first concentration parameter

322-2 second concentration parameter

BM calculation model

34 acknowledgement signal

S sensor for measuring conductivity

41 measured conductivity

42 authentication signal

43 error notification

df dialysis fluid

51 reading the mixing ratio data set

52 detecting constituent parameters

53 calculation result data group

54 check whether the resulting concentration is within the standard range

56 identified as a recipe

57 store recipe

Claims

1. A method for calculating a result data set (331) on the basis of a calculation model (BM) for the conductivity of a dialysis liquid, the result data set being a result data set relating to the composition of the dialysis liquid (df) to be mixed by a plurality of components, the method having the following method steps:

-reading (51) a mix ratio data set (311) representing a mix ratio of at least one a-component-and optionally B-component-and a third component;

-detecting (52) composition parameters comprising a first substance concentration parameter (322-1) representing the concentration of a substance in the a-composition and optionally a second substance concentration parameter (322-2) representing the concentration of a substance in the B-composition;

-calculating (53) the result data set (331) regarding the resulting composition of the dialysis liquid (df), the result data set comprising a description of a substance concentration in the dialysis liquid and a description of a desired value of the conductivity of the dialysis liquid based on the calculation model (BM).

2. The method according to claim 1, wherein the method comprises the steps of:

-checking (54) whether the substance concentrations out of the calculated result data set (331) are respectively in a predefined standard range, and if so, saving the mixing ratio data set (311) as a confirmed formula for the dialysis liquid.

3. Method according to the preceding claim, wherein in the case 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 of the preceding claims, wherein the method additionally comprises the method steps of:

-displaying the concentration of the substance, and/or

-issuing a warning notification in case the substance concentration is not successfully checked to comply with the standard range.

5. Method according to any of the preceding claims, wherein the substance concentration is a salt concentration and wherein the calculation model (BM) is based on a salt strength, wherein the salt strength is a measure of the sum of all molar concentrations of all salts, and wherein in the calculation model (BM) the electrical conductivity is related to the salt strength.

6. The method of any one of the preceding claims, wherein the composition parameter comprises a glucose concentration.

7. Method according to the preceding claim, wherein a control command is generated only when a confirmation signal has been detected indicating that the recipe has been confirmed.

8. A calculation unit (R) for calculating a result data set (331) based on a calculation model (BM) for the conductivity of a dialysis liquid for preparing the dialysis liquid (df) consisting of a plurality of components, the calculation unit having:

-a reading interface (31), the reading determining for reading a mix ratio data set (311) representing a mix ratio of at least one a-component and one B-component and a third component;

-a composition interface determining parameters (32) for detecting a composition, the composition parameters comprising a first substance concentration parameter (322-1) representing a concentration of a substance in the a-composition and a second substance concentration parameter (322-2) representing a concentration of a substance in the B-composition;

-a processor (P) determining the result data set (331) for calculating a resulting composition in respect of the dialysis liquid (df) to be produced, the result data set comprising a description of a substance concentration in the dialysis liquid and a description of a desired value of the conductivity of the dialysis liquid based on a calculation model (BM).

9. The computing unit (R) according to the preceding claim directed to the computing unit, additionally comprising:

-a User Interface (UI) via which a confirmation signal can be received; and/or

-a memory (DB) for storing the confirmed recipes.

10. The calculation unit (R) according to any of the preceding claims directed to it, additionally comprising:

-a sensor interface (34) for receiving a sensor signal relating to the measured conductivity (41) of the dialysis liquid (df);

and wherein the calculation unit (R) is designed to compare the consistency of the measured conductivity (41) of the dialysis liquid (df) with an expected preset value and/or with the calculated expected value in order to issue an error notification in the absence of consistency.

11. A mixing apparatus (M) for preparing a dialysis liquid (df) composed of a plurality of components for a dialysis machine (DG), the mixing apparatus having:

-an electronic interface to a computing unit (R) according to any one of the preceding claims relating to said computing unit;

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

-optionally: a B connection to a second container (1B) for providing a B component;

-a third connection to a third vessel (1C) for providing RO water;

-a mixing mechanism for mixing the dialysis liquid (df) by at least the a-component, optionally B-component and RO water in a mixing chamber according to a preset of a result data set (331) provided by the calculation unit (R).

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

13. Operating method according to the preceding claim for the operating method for monitoring a mixing device (M) and a dialysis liquid (df) mixed by means of the mixing device in that the current conductivity of the prepared dialysis liquid (df) is measured and compared with a desired preset value and/or with a calculated desired value in order to issue an error notification in the absence of consistency.

14. The operating method according to the preceding claim, wherein it is checked automatically: for the contents indicated in the result data set (331) and/or in the recipe, whether the respective container (1A, 1B, 1C, 1D.) has already been connected to the mixing device (M) for mixing in each case is determined by comparing the identity of the contents identification code at the respective container (1A, 1B, 1C, 1D.) with the respectively stored reference.

15. Dialysis machine (DG) having a calculation unit (R) according to the preceding claim for said calculation unit.

16. Dialysis machine (DG) having a mixing device (M) according to the preceding claim relating to said mixing device.