Generating medical fluids for renal replacement therapy

Abstract

A system is configured to generate a medical fluid for renal replacement therapy by mixing fluids in-line. The system includes a first flow path (12), a second flow path (16), a first sensor (20) in the first flow path, and a second sensor (20 ') in the second flow path. The first sensor and the second sensor measure component-related parameters. The system is operable to deliver at least one of the fluids to the first sensor and the second sensor during a calibration phase and to determine a conversion function for converting between a first signal of the first sensor and a second signal of the second sensor during the calibration phase based on the first signal of the first sensor and the second signal of the second sensor. In a generation phase, the system is operable to control the at least one pump based on a converted measurement given by performing a conversion function on a measurement in the first signal from the first sensor.

Description

Technical Field

[0001] This disclosure relates to the field of renal replacement therapy, and more particularly to the generation of medical fluids used in such therapy. Background Technology

[0002] Renal replacement therapy (RRT) is a treatment that replaces the normal blood-filtration function of the kidneys. RRT is used when kidney function is impaired (a condition known as kidney failure, including acute kidney injury (AKI) and chronic kidney disease (CKD)). RRT involves removing water from the blood of a patient with kidney failure and exchanging solutes with the blood. One example of RRT is extracorporeal blood therapy, where blood circulates outside the patient's body and is in contact with one or more medical fluids at an interface. Modes of extracorporeal blood therapy include hemodialysis (HD), hemofiltration (HF), and hemodiafiltration (HDF). Another example of RRT is peritoneal dialysis (PD), where medical fluids are infused into the patient's peritoneal cavity to interface with the patient's blood through the peritoneum.

[0003] The medical fluids used in HD and PD are generally referred to as dialysis fluids. In HF, the medical fluid is called a replacement fluid because it is infused into the patient's bloodstream to replace fluids removed during treatment. In HDF, both dialysis fluids and replacement fluids are used.

[0004] Compared to CKD patients, AKI patients are treated with extracorporeal blood via HD, HF, or HDF using different types of dialysis machines. Generally, AKI patients are treated continuously for longer periods and at lower fluid flow rates compared to CKD patients. This continuous treatment is often referred to as CRRT (Continuous Renal Replacement Therapy). To ensure accurate and continuous monitoring and control of fluid removal (called ultrafiltration), AKI machines are typically equipped with scales to measure the weight of freshly treated fluid and the weight of waste treated fluid during treatment. CKD machines, on the other hand, use flow meters or volumetric pumps to control ultrafiltration.

[0005] A PD machine (also known as a circulator) may include at least one scale to measure the weight of fresh treatment fluid infused into the peritoneal cavity and the weight of waste treatment fluid withdrawn from the peritoneal cavity.

[0006] RRT consumes a significant amount of medical fluid over time. In some RRT models, pre-filled medical fluids are delivered to the point of care in pre-filled bags. For example, this is used during routine PD (Physical Discharge) using pre-filled bags. AKI (Area-In-Knowledge) machines are configured to use medical fluid pre-filled bags by having a worker place the pre-filled bag on one of the scales before processing and replace it as needed. On the other hand, CKD (Care-Discharge) machines integrate the ability to generate medical fluids on demand by mixing one or more concentrates with water, a so-called online fluid generation. Recently, PD machines integrating online fluid generation capabilities have been proposed.

[0007] There is a general expectation to advance the online generation of medical fluids for various types of RRT. Given the installed base of dialysis machines, there is also a desire to provide a simple technique for reconfiguring existing dialysis machines to generate their own medical fluids. Summary of the Invention

[0008] The aim is to at least partially overcome one or more limitations of the existing technology.

[0009] Another objective is to increase the number of machines that can be used to generate medical fluids for RRT online.

[0010] Another objective is to achieve accurate online generation of medical fluids at low cost.

[0011] One or more of these objectives, as well as other objectives that may be apparent from the following description, are achieved, at least in part, by a system for generating a medical fluid for renal replacement therapy, a control method, a computer-readable medium, and a disposable device, embodiments of which are defined by the dependent claims.

[0012] Other objects and aspects, as well as embodiments, features and technical advantages, will become apparent from the following detailed description, the appended claims and the accompanying drawings. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of an example system for generating medical fluids.

[0014] Figure 2A It is an operation Figure 1 A flowchart of an example method of the system. Figure 2B yes Figure 2A The flowchart illustrates an example implementation of the data collection step in the method.

[0015] Figure 3 It is a chart of calibration data obtained during the calibration phase.

[0016] Figure 4 It is used to generate for Figure 1 A schematic diagram of the control system for the pump control signals in the system.

[0017] Figures 5A to 5B They are used for Figure 1 A schematic diagram of disposable devices and machines in the system.

[0018] Figure 6 yes Figure 1 A schematic diagram of a variant of the system.

[0019] Figure 7 It is an operation Figure 6 A flowchart of the methods in the system.

[0020] Figure 8 This is a flowchart of an example method for configuring a system for generating medical fluids.

[0021] Figure 9 This is a schematic diagram of an example water supply device that includes a reusable sensor.

[0022] Figures 10A to 10B This is a side view of a reusable sensor before and after manipulating a disposable pipeline assembly to encapsulate fluid within the sensor.

[0023] Figure 11 This is a flowchart of an example procedure for fluid control during an interruption of dialysis treatment.

[0024] Figure 12 This is a schematic diagram of a subsystem used to generate liquid concentrate from dry concentrate. Detailed Implementation

[0025] Embodiments will now be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, of the embodiments. In fact, the subject matter of this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure may satisfy applicable legal requirements. The same numerals throughout refer to the same elements.

[0026] Furthermore, it should be understood that, where possible, any advantages, features, functions, apparatus and / or operational aspects of any embodiment described and / or contemplated herein may be included in any other embodiment described and / or contemplated herein, and / or vice versa. Additionally, where possible, unless expressly stated otherwise, any term expressed herein in the singular is intended to also include the plural form and / or vice versa. As used herein, “at least one” shall mean “one or more”, and these phrases are intended to be interchangeable. Thus, the terms “a” and / or “an” shall mean “at least one” or “one or more”, even though the phrases “one or more” or “at least one” are used herein. As used herein, unless otherwise required by the context due to the language of expression or necessary meaning, the word “comprising” or variations such as “including” or “containing” are used in an inclusive sense, i.e., specifying the presence of the stated feature but not excluding the presence or addition of other features in various embodiments.

[0027] It will also be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the terms “multiple,” “plural,” and “plurality” are intended to imply the provision of two or more elements, while the term “group” implies the provision of at least one element. The term “and / or” includes any and all combinations of one or more of the associated listed elements.

[0028] For the sake of brevity and / or clarity, well-known functions or structures may not be described in detail. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0029] This disclosure relates to techniques for generating medical fluids online for use in renal replacement therapy (RRT). As used herein, RRT refers to any treatment that replaces or supplements the normal blood filtration function of a patient's kidneys. RRT may involve the removal of water from a patient's blood and the exchange of solutes with the blood.

[0030] As used herein, online fluid generation refers to the dynamic generation of medical fluids by mixing various components in appropriate proportions. Online fluid generation can include on-demand fluid generation, where the generation rate of the medical fluid is adjusted to match the medical fluid consumption rate of, for example, an ongoing RRT (Recovery Therapy). It is also conceivable to achieve online fluid generation independent of the medical fluid consumption rate, for example, by providing the generated medical fluid to a storage tank or reservoir.

[0031] Medical fluids can be any fluid consumed as part of RRT and are also referred to as “processing fluids.” In the context of extracorporeal blood therapy, the medical fluid can be a dialysis fluid that comes into contact with the blood interface in a filtration unit commonly referred to as a “dialyzer.” Alternatively or additionally, the medical fluid can be a so-called replacement fluid or substitute fluid that is infused into the blood upstream or downstream of the dialyzer, for example as part of hemofiltration (HF) or hemodialysis filtration (HDF), as is well known in the art. In the context of PD, the medical fluid can be a dialysis fluid that is infused into the patient’s peritoneal cavity and comes into contact with the patient’s blood interface through the peritoneum lining the peritoneal cavity.

[0032] The medical fluids used in RRT have well-defined compositions that are tailored to specific treatments and patients. In online generation, the composition of the medical fluid can be provided by medical guidelines and / or set by caregivers for a particular patient or patient group. Medical guidelines can also define permissible deviations from the nominal concentrations of various solutes in the medical fluid.

[0033] As used herein, a "disposable device" (or component / arrangement / sensor, etc.) is intended for use only for a limited time after which it is replaced with a new disposable device. Depending on the disposable device, this limited time may correspond to a single treatment session or a predetermined number of single treatment sessions, or it may be given by a predetermined maximum time period. Alternatively, the disposable device may be replaced whenever a new patient is to be treated.

[0034] As used herein, a “reusable device” (e.g., a sensor) is a device with a longer lifespan than its corresponding disposable device. Therefore, when a disposable device is discarded and replaced with a new disposable device, a reusable device remains available for its intended use. In some embodiments, a reusable device does not require replacement at all. Thus, its lifespan is, at least in theory, unlimited. Although such a device may be replaced if it is deemed to have failed, it is generally referred to as “permanent” or “permanently installed.”

[0035] As used in this article, a “treatment session” refers to the period of time during which a patient uses a dialysis machine to receive renal replacement therapy (RRT). This period begins when the patient is connected to the dialysis machine and ends when the patient is disconnected from the dialysis machine.

[0036] In the technique presented herein, medical fluids are generated as mixtures of two or more component fluids. For example, a medical fluid could be a dialysis fluid, generated by mixing water with one or more concentrates. One way to generate dialysis fluid is by utilizing conductivity as feedback for the quantitative addition of the corresponding concentrate. This is common practice in CKD machines. Such CKD machines include an internal mixing system for generating dialysis fluid online by mixing water with one or more concentrates. One or more concentrates can be provided in separate containers or bags fluidly connected to the CKD machine. The mixing system includes multiple permanent components, including fluid paths, valves, pumps, and sensors (including one or more conductivity sensors). The CKD machine also includes an internal cleaning system operable to intermittently clean and sterilize the mixing system to ensure bacterial inactivation. For example, the cleaning system can be activated after each single treatment. Using a cleaning system also ensures the correct composition of the dialysis fluid. If the mixing system is used continuously without cleaning, the internal dimensions of the fluid paths and sensors may change due to the accumulation of deposits. For example, deposits inside a conductivity sensor can cause the measured conductivity to drift, for instance, by altering the distance between the electrodes (cell constant) and / or the dimensions of the flow path through the conductivity sensor. Deposits can also affect the contact between the electrodes and the fluid.

[0037] As described in the background section, there is a desire to advance the online generation of dialysis fluid. A large number of dialysis machines have been installed in healthcare facilities worldwide. Existing AKI and PD machines are configured to use dialysis fluid in the form of pre-filled bags. Therefore, there is a need for a simple technique to reconfigure existing dialysis machines to generate dialysis fluid online by mixing water with one or more concentrates, wherein the respective concentrates are supplied to the dialysis machine in the form of containers or bags.

[0038] The applicant has conceived of designing a disposable device with a customized fluid pathway to generate dialysis fluid online through mixing within the device. Such a disposable device is commonly referred to as a "lineset," although it does not necessarily consist solely of fluid lines. The disposable device is mounted to engage with a pump on a dialysis machine and connected to a water and concentrate source, which in turn operates the dialysis machine to meteredly add and mix water and concentrate in the fluid pathway within the disposable device to generate dialysis fluid online. The disposable device can be replaced after a single treatment or at fixed time intervals to ensure the sterility of the dialysis fluid.

[0039] In this context, one problem is that the quantitative addition of concentrate is typically based on conductivity measurements, which require highly accurate conductivity sensors. Such sensors are expensive. If a disposable device includes one or more expensive conductivity sensors, and these sensors are discarded after a short period of use, the cost of dialysis treatment increases dramatically. Inexpensive conductivity sensors are also available commercially. However, inexpensive conductivity sensors generally lack the accuracy required to control the quantitative addition of concentrate.

[0040] One solution to this problem might be to use a concentrate with a highly defined composition. If the composition of the concentrate is known with high accuracy, then water and concentrate can be added in precise proportions without the need for conductivity feedback, provided that the water and concentrate are added in precise quantities by a highly accurate pump. However, given that the concentrate is supplied in containers or bags, the composition of the concentrate may change over time due to water migration through the container walls. To ensure high accuracy of composition, it is necessary to shorten the lifespan of the concentrate container and / or require the container to include a highly efficient water vapor barrier. Both of these alternatives increase the cost of the concentrate, thereby increasing processing costs.

[0041] The technology presented in this paper is based on the insight that a lower-accuracy conductivity sensor can be included in a disposable device if it can be calibrated as needed using a higher-accuracy conductivity sensor. Therefore, the lower-accuracy sensor (“first sensor”) is a relatively inexpensive sensor and can be discarded as part of a disposable device after use. The higher-accuracy sensor (“second sensor”) may be more expensive and have a longer service life compared to the lower-accuracy sensor. Therefore, the lower-accuracy sensor is arranged to control the mixing used to generate the dialysis fluid and is exposed to the majority of the fluid delivered through the disposable device. The higher-accuracy sensor is fluidly connected to the disposable device and is used to calibrate the lower-accuracy sensor during startup and / or periodically.

[0042] The proposed technology promises to expand the number of machines capable of generating dialysis fluid online, including existing dialysis machines originally configured to use pre-filled bags. Expanding the online generation of dialysis fluid will reduce the need for pre-filled bags, resulting in environmental benefits such as reduced transport space and plastic consumption. Furthermore, staff will no longer need to store, manage, and dispose of heavy pre-filled bags, for example, in intensive care units.

[0043] Although conductivity sensors have been discussed above, the proposed technique is applicable to any type of sensor capable of measuring fluid parameters related to the composition of the fluid being measured. As used herein, such fluid parameters are expressed as composition-related parameters (CRPs). Alternatively, fluid parameters can be expressed as concentration-related parameters. In some embodiments, CRP represents conductivity, or equivalently resistivity, which corresponds to the concentration of current-carrying ions in the fluid being measured. In a variation, CRP represents the concentration of a substance or solute in the fluid. In medical fluids, such a substance can be an electrolyte such as bicarbonate, sodium, potassium, calcium, magnesium, or chloride. The concentration of any such substance can be measured by an ion-selective sensor. If the medical fluid is used in generating PD, a substance acting as a permeabilizer, such as glucose, may be present in the medical fluid, and CRP can represent the concentration of this permeabilizer. In another alternative, CRP can represent the concentration of hydrogen ions, for example, expressed as a pH value. Therefore, in some embodiments, the CRP sensor can be represented by a conductivity sensor, a resistivity sensor, an ion-selective sensor, a glucose sensor, a pH sensor, or any combination thereof. It is important to understand that the first and second sensors described above can be of different types. As an alternative to the listed CRP sensor examples, the second sensor could be a LIBS (Laser-Induced Breakdown Spectroscopy) sensor, a BGA (Blood Gas Analyzer) sensor, or any other type of sensor commonly used for high-accuracy concentration measurements in fluids.

[0044] Furthermore, the proposed technique of calibrating the first sensor using a second sensor and then controlling fluid mixing using the first sensor to generate a medical fluid is also applicable to situations where both the first and second sensors are disposable or reusable components. Similarly, the proposed technique is not limited to including the first sensor in a disposable device with a customized fluid path to achieve online generation of medical fluid by mixing within it.

[0045] Now refer to Figure 1 Various embodiments are described. Figure 1An example system 1 for generating medical fluids online for any type of RRT is shown. In the illustrated example, the medical fluid is generated by mixing two fluids, F1 and F2 (“component fluids”). The medical fluid is supplied to a receiving device 30. In some embodiments, the medical fluid is a dialysis fluid used in extracorporeal blood therapy (such as HD or HDF), and the receiving device 30 includes a dialyzer. In some embodiments, the medical fluid is a displacement fluid used in HF or HDF, and the receiving device 30 includes infusion ports on blood extraction lines and / or blood return lines. In some embodiments, the medical fluid is a dialysis fluid used in PD, and the receiving device 30 includes a disposable fluid loop attached to a PD circulator. It is also conceivable that the receiving device 30 corresponds to the peritoneal cavity itself. In some embodiments applicable to all types of RRT, the receiving device 30 is a reservoir for collecting medical fluid for subsequent RRT use. In these embodiments, the medical fluid is not generated on demand. The reservoir may or may not be connected to the system for dialysis therapy, or may or may not be part of the system for dialysis therapy.

[0046] Fluids F1 and F2 are stored in corresponding containers 3a and 3b. Containers 3a and 3b can be rigid or flexible and can be made of any material (e.g., plastic). In some embodiments, the first fluid F1 in the first container 3a is water, while the second fluid F2 in the second container 3b is a liquid concentrate. System 1 also includes a pump assembly 4, which includes pumping devices (“pumps”) P1 and P2. The corresponding pumps P1 and P2 can be of any type. Figure 1 In the example, it is assumed that at least pump P2 is blocked, meaning that when pump P2 is disabled, it blocks the flow of fluid. If the fluid path in system 1 is defined by a disposable device (as shown below), then pumps P1 and P2 are typically peristaltic pumps that engage with the outside of a dedicated conduit. Pumps P1 and P2 operate in response to control signals C1 and C2.

[0047] The main fluid line 12 extends from the first container 3a to an outlet for medical fluid, where the outlet includes a connector 12a for connection to a corresponding connector 30a of the receiving device 30. The main fluid line 12 forms the main supply path (“first flow path”) for the medical fluid. A connecting fluid line 13 extends from the second container 3b to a connector 13b on the main fluid line 12. The system 1 is configured to allow the F2 flow to merge with the F1 flow in the main fluid line 12 within and downstream of the connector 13b, forming a mixture. The mixing of F1 and F2 can be completed at the connector 13b, or it can be completed at the CRP sensor 20 (below). In the example shown, pump P1 is arranged in the main fluid line 12 to limit the flow rate of the medical fluid (“main flow rate”), while pump P2 is arranged in the connecting fluid line 13 to limit the flow rate of fluid F2. Thus, pump P2 is operable to control the amount of F2 mixed into the F1 within the main fluid line 12.

[0048] Although Figure 1 Not shown, but system 1 may include, for example, one or more devices configured to facilitate mixing within connector 13b. In some embodiments, connector 13b is a tee connector. A non-limiting example of a tee connector with mixing enhancement devices is disclosed in WO2009 / 030973, which is incorporated herein by reference. In a variant, the mixing enhancement device may be detached from connector 13b and located downstream of connector 13b. Such detached devices may be configured to increase the Reynolds number of at least one of the mixture and / or the inflow fluid flow. Alternatively, the detached devices may be configured as a conventional static mixer, or as a circulation loop in which the mixture is circulated to facilitate mixing before it is delivered to receiving device 30.

[0049] A diversion line or discharge line 16 (“second flow path”) extends from the main fluid line 12 toward the discharge section 17 or toward a container (not shown) for collecting waste fluid. A valve assembly 15 is arranged in the main fluid line 12 to selectively divert fluid from the main fluid line 12 to the diversion line 16 by opening a passage from the main fluid line 12 to the diversion line 16. In some embodiments, the valve assembly 15 is operable to direct all inflowing fluid along the main fluid line 12 toward the receiving device 30 or to direct all inflowing fluid along the main fluid line 12 into the diversion line 16. The valve assembly 15 may include any number of valves and is operated based on one or more control signals (collectively represented as control signal C3). If the fluid path is defined by a conduit, the valve assembly 15 may include a pinch valve that engages with the outside of the conduit.

[0050] The first CRP sensor 20 is disposed in the main fluid line 12 between pump P1 and valve assembly 15 (as shown) or in the main fluid line 12 between connector 13b and pump P1. The second CRP sensor 20' is disposed in fluid communication with the branch line 16. CRP sensors 20 and 20' are configured to output corresponding measurement signals S1 and S1', which indicate composition-related parameters of the fluid flowing through them. In some embodiments, the two output signals S1 and S1' represent the same composition-related parameter, such as conductivity.

[0051] As previously stated, the first fluid F1 can be water, which is the main component of any medical fluid. To maintain a continuous production of medical fluid, it may be necessary to replenish container 3a. For this purpose, system 1 includes a water supply device 10 configured to generate water of sufficient mass for use in medical fluid production. The water supply device 10 is connected to container 3a via a water supply line 11. The water supply device 10 is operable to supply water to container 3a during a refilling phase according to a control signal C4 to completely or at least partially refill container 3a. The refilling phase can be selectively initiated when container 3a is considered sufficiently empty. The amount of fluid in container 3a can be determined by control device 40 based on signal S2 from scale 2a (as shown below). Alternatively, the amount of fluid in container 3a can be estimated by determining and integrating the flow rate of F1 in the main fluid line 12. The flow rate can be given by a flow meter (not shown) or estimated based on the pumping speeds of pumps P1 and P2.

[0052] In the example shown, system 1 includes a disposable device that engages with the machine. References will be made below. Figures 5A to 5B The disposable device and machine are described in more detail. In the example shown, the first CRP sensor 20 is disposable and therefore included in the disposable device; while the second CRP sensor 20' is a reusable sensor and therefore not included in the disposable device. For replacing the disposable device, system 1 includes multiple connectors. Connector 11a is configured for detachable connection to the water supply device 10. Connector 13a is configured for detachable connection to the container 3b. Connector 16a is configured for detachable connection to the reusable CRP sensor 20'. As previously described, system 1 also includes connector 12a for detachable connection to the receiving device 30.

[0053] In the example shown, system 1 includes scales 2a and 2b, configured to provide corresponding weight signals S2 and S3 representing mass. Containers 3a and 3b are arranged on the respective scales 2a and 2b. Containers 3a and 3b may be positioned on scales 2a and 2b, rather than suspended from them as shown. Scales are typically included in machines used for AKI and PD treatment and are used to monitor the amount of fluid in different containers, for example, to determine the amount of fluid (“ultrafiltrate”) extracted from the patient during treatment.

[0054] Control device 40 is configured to control the operation of system 1. If system 1 is operated by a dialysis machine, control device 40 may be the controller of the dialysis machine or a separate controller. Control device 40 is configured to receive measurement signals (here, S1', S1, S2, S3) and output control signals (here, C1, C2, C3, C4). Control device 40 may be configured to generate control signals according to a control program and based on the measurement signals. The control program includes computer instructions. Control device 40 includes processing circuitry, which includes one or more processors 41 and a computer memory 42. The control program is stored in memory 42 and executed by processor 41. The control program may be provided to control device 40 on a computer-readable medium, which may be a tangible (non-transient) product (e.g., magnetic media, optical disc, read-only memory, flash memory, etc.) or a transmitted signal. Although Figure 1 Although not shown, control device 40 may be connected to one or more input devices that enable an operator to input control data, and one or more UI devices for providing feedback data to the operator. For example, input devices may include a keyboard, keypad, computer mouse, control buttons, touchscreen, printer, microphone, etc., and UI devices may include a display device, touchscreen, indicator lights, alarm devices, speaker, etc. The operator may be a person with clinical experience (such as a doctor or nurse), or may be a patient.

[0055] Figure 2A This is a flowchart of an example method 200 for operating a system for generating medical fluids online. This method is generally applicable to any such system, but will be referenced from [the original text]. Figure 1The method is described in System 1. Method 200 is performed by control device 40. Method 200 includes a calibration phase CP and a production phase PP. The calibration phase is performed at least when System 1 is started. One or more calibration phases may also be performed during the operation of System 1 by transitioning System 1 from the production phase to the calibration phase and resuming the production phase after the calibration phase is completed. For example, System 1 may enter the calibration phase at fixed intervals, or whenever a new container 3b of liquid concentrate is installed. Alternatively or additionally, the system may enter the calibration phase whenever the speed of a pump in the pump assembly deviates from the operating speed range. The operating speed range may be defined as the range of permissible speed values ​​for the corresponding pump, or the permissible variation in the speed of the corresponding pump, for example, relative to the initial speed of the corresponding pump at the start of the current production phase.

[0056] Whenever the first CRP sensor 20 is discarded and replaced with a new first CRP sensor, the system 1 can also repeat the calibration phase. This calibration phase is used to determine the conversion function (as follows) between the signal S1 of the first CRP sensor 20 and the signal S1' of the second CRP sensor 20'.

[0057] In the illustrated example, the calibration phase includes step 201, which involves operating valve assembly 15 and pump assembly 4 via control signals C1-C3 to deliver at least one of the component fluids F1 and F2 to the first CRP sensor 20 and the second CRP sensor 20'. Therefore, step 201 ensures that both sensors 20 and 20' are exposed to fluids of the same composition. In step 202, calibration data from signals S1 and S1' during step 201 is processed to determine a conversion function for converting the signal value in signal S1 to the signal value in signal S1'. In the generation phase (step 203), valve assembly 15 and pump assembly 4 are operated via control signals C1-C3 to pump component fluids F1 and F2 through the main fluid line 12, thereby providing medical fluid at outlet 12a. Thus, the mixture of F1 and F2 flows only through the first sensor 20, and the generation of the medical fluid is controlled based on signal S1 from the first sensor 20. Specifically, as shown in steps 203a-203c, the pump unit 4 is controlled at least in part based on the transformed signal value given by running a transformation function on the signal value in signal S1.

[0058] Steps 203a-203c represent an example control sequence, which is repeatedly executed by control device 40 to operate system 1 via control signals C1 and C2 during the generation phase. In step 203a, a measured CRP value is obtained from the first sensor 20. In step 203b, a converted CRP value is generated by running a conversion function on the measured CRP value from step 203a. This converted CRP value estimates the CRP value that should have been measured by the second sensor 20'. In step 203c, based on the converted CRP value from step 203b, one or more pumps within the pump assembly in system 1 are controlled to generate a medical fluid with a target component (e.g., given by a target CRP value). Figure 1 In a specific example, pump P1 can be operated to generate the target flow rate, and pump P2 can be operated to obtain a converted CRP value that matches the target CRP value.

[0059] Figure 2B This is a flowchart illustrating an example of data collection step 201. In step 201a, the operating system generates a test fluid and supplies it to two sensors 20, 20'. In step 201b, a first CRP value of the test fluid is obtained from the first sensor 20, and a second CRP value of the test fluid is obtained from the second sensor 20'. Both the first and second CRP values ​​represent the test fluid and form a data pair. Hereinafter, such a data pair is referred to as a "sampled data pair" or SDP. Depending on the specific implementation, step 201b may generate a single SPD or multiple SDPs of the test fluid. For example, a single SPD may be given as the average signal value ("time average") of the corresponding signals S1, S1' over a time window. Figure 2B As indicated by the arrows, steps 201a-201b can be repeated an arbitrary number of times for different test fluids. Each test fluid has a unique composition and is a unique combination of available fluids. Figure 1 In the examples, the test fluid may consist of only F1 (without F2), only F2 (without F1), or a mixture of F1 and F2. Different test fluids may be formed from mixtures of F1 and F2 in different proportions.

[0060] Figure 3This is a graph showing the CRP values ​​in output signal S1 on the x-axis and in output signal S1' on the y-axis. Sampling data pairs for different test fluids are represented by points. Each sampling data pair is determined by time averaging. Sampling data pair M1 is given by CRP1 and CRP1' and obtained by feeding fluid F1 to two sensors 20 and 20'. Sampling data pair M2 is given by CRP2 and CRP2' and obtained by feeding a mixture of fluids F1 and F2 to two sensors 20 and 20'. The transformation function CF is determined by fitting a linear function to M1 and M2, for example, by linear regression. As shown by dashed points M3 and M4, step 201 can provide additional SDPs, and step 202 uses these additional SDPs to determine the transformation function. The transformation function does not have to be linear but can be nonlinear, such as a polynomial function, spline function, etc. It is conceivable that the transformation function can be constrained based on the SDP of a single test fluid by assuming that the transformation function intersects the x-axis or y-axis at a specific CRP value (e.g., at the origin (0,0)).

[0061] The accuracy of the conversion function affects the accuracy of the composition of the medical fluid. The calibration phase can be customized to improve the accuracy of the conversion function. This can be achieved by performing step 201 to deliver a test fluid with the same composition as the expected medical fluid composition (i.e., the target composition) through sensors 20, 20', and using the SDP of that test fluid in step 202. Thus, the medical fluid is provided as the test fluid during the calibration phase. Furthermore, when determining the conversion function, the SDP of that test fluid can be given a higher weight compared to the SDPs of other test fluids. It is also possible to consider delivering one or more test fluids with compositions close to and / or approximating the target composition to increase the number of SDPs to be used in step 202. However, the consumption of component fluids increases with the number of test fluids, as does the duration of the calibration phase. Therefore, in some embodiments, the number of test fluids is in the range of 2 to 5.

[0062] In a non-restrictive example, the least squares method is used to determine the transformation function. If the correlation between the CRP values ​​from sensors 20 and 20' is expected to be linear, the following transformation function applies: , in, The CRP value is from sensor 20. The CRP value is from sensor 20', and and The gain and bias are for linear correlation. and The value can be obtained by minimizing the error vector in the following equation. get: , in, It is a vector containing the CRP values ​​from sensor 20'. It is a regression matrix, and It includes and The linear correlation vector of values. Assuming step 201 produces three SDPs: CRP1:CRP1', CRP2:CRP2', and CRP3:CRP3', then the following data elements are present: , , It can be shown that when At that time, the error vector Minimize, and thus obtain the transformation function. and The value of .

[0063] exist Figure 1 In a specific example, only F1 or a mixture of F1 and F2 can be delivered through sensors 20 and 20'. If pump P1 is operated and pump P2 is stopped, F1 will be delivered through the main fluid line 12 into the branch line 16. If both pumps P1 and P2 are operated, a mixture of F1 and F2 will be delivered into the branch line 16. The ratio between F1 and F2 can be adjusted by the speeds of the corresponding pumps P1 and P2. See below for further details. Figure 7 A detailed example of step 201 is given.

[0064] exist Figure 1 In System 1, when valve assembly 15 leads to branch line 16, sensors 20 and 20' are arranged in series. Therefore, in step 201, the same fluid will naturally flow through both sensors 20 and 20'. In some embodiments, the CRP values ​​of SDP can be obtained simultaneously from sensors 20 and 20' by waiting until the signal values ​​in S1 and S1' are sufficiently stable, and then extracting the corresponding CRP values ​​from S1 and S1'. It is also conceivable to obtain the CRP values ​​of SDP at different time points by considering the positions of the respective sensors 20 and 20'. Figure 1 The CRP value can be extracted from the output signal S1 at the first time point and the output signal S1' at the second time point, where the difference between the second and first time points corresponds to the time offset of the distance between sensors 20 and 20' along the flow path. This time offset can be calculated based on the current flow rate of the fluid. For example, the time offset can be estimated by assuming a piston flow along the flow path. In one example, the time offset is given by V / D, where V is the volume of the flow path between sensors 20 and 20', and D is the flow rate.

[0065] It should be noted that sensors 20 and 20' do not require a fluid series connection during step 201. In an alternative (not shown), system 1 is instead configured such that sensors 20 and 20' are in parallel flow paths, and valve assembly 15 is operable to direct fluid to sensor 20 or sensor 20'. In this variation, the obtained CRP values ​​for SDP can have relatively large time intervals.

[0066] The determination or establishment of fluid flow rates mentioned in this specification can be performed in different ways. In a first example, the system may include one or more flow meters. For example, the flow meters may be arranged in the main fluid line 12 downstream of pump P1 or in the connecting line 13. In a second example, the flow rate may be given by the pumping speed of the pump. For example, pump P1 and / or pump P2 may be positive displacement pumps with known stroke volumes, and the flow rate may be calculated as the product of the stroke volume and the number of strokes per unit time (pumping speed). Alternatively, the pumping speed may be converted to flow rate based on tabular data. In a third example, the flow rate may be determined based on weight signals S2 and S3 from scales 2a and 2b. Therefore, the flow rate of fluid F1 is given by the weight change of container 3a, while the flow rate of fluid F2 is given by the weight change of container 3b.

[0067] Figure 4 This is a schematic diagram of a control system 400 used in operating system 1 during the generation phase. The control system 400 uses feedback control and may be part of the control device 40. Figure 4 In the example, the control system 400 is configured to generate Figure 1 The control system 400 receives a control signal C2 from the pump P2 and a signal S1 from the sensor 20. The control system 400 includes a target unit 401 configured to generate a target signal representing a target component of the medical fluid to be generated during the generation phase. 1. Target signal 1. A target CRP value can be specified. The control system 400 also includes a subtraction unit 402, which is configured to output a signal representing the target. 1 and actual value signal The error signal E represents the instantaneous difference between 1 and 1. The actual value signal is also present. Each signal value in step 1 is a converted CRP value (see step 203b). Controller 403 is configured to generate control signal C2 based on error signal E. Controller 403 can be of a conventional type, such as a P controller, PI controller, or PID controller. Calculation unit 404 is configured to generate actual value signals based on signal S1 from sensor 20 using conversion function CF. 1. Therefore, the computing unit 404 can perform... Figure 2ASteps 203a-203b are performed in the process, while step 203c is performed by a combination of the target unit 401, the subtraction unit 402 and the controller 403.

[0068] It is conceivable that, for example, the target flow rate of the medical fluid could be altered during the generation phase, either according to a predetermined plan or through operator intervention (e.g., via an input device (not shown) connected to control device 40). Figure 1 In System 1, control device 40 adjusts the target flow rate by changing the speed of pump P1. Similarly, the target composition of the medical fluid can be changed during the generation stage. This corresponds to... Figure 4 Target signal 1. In some embodiments, the control device 40 may operate the valve assembly 15 via the control signal C3, thereby intermittently diverting the medical fluid into the diversion line 16 whenever the target flow rate or target composition is to be changed, in order to reduce the risk of delivering an incorrectly composed mixture to the receiving device 30 when adjusting the speed of pump P1 or pump P2.

[0069] In some embodiments, control device 40 executes a monitoring procedure during the generation phase, wherein the speed of the pumps in the pump group is evaluated relative to group speed limits to detect operational errors. Errors in system 1 (e.g., fluid line kinks or mechanical failure of the pumps) can cause significant variations in pump speed. Group speed limits define maximum and / or minimum speed limits for the respective pumps. If the current speed of a pump is found to be below its minimum speed limit or above its maximum speed limit, control device 40 can stop pumps P1, P2 and / or generate an alarm via a UI device (not shown). As an alternative or supplementary method to monitoring pump speed, changes in the weight of containers 2a, 2b, as given by output signals S2, S3 of scales 2a, 2b, can be evaluated to detect operational errors.

[0070] In some embodiments, the control device 40 performs a verification operation during the generation phase, wherein the valve assembly 15 is actuated to direct at least a portion of the medical fluid into the shunt line 16. Thus, the medical fluid is directed through both the first sensor 21 and the second sensor 21'. The verification operation may be performed periodically or may be triggered by an event such as a gradual drift or step change in the speed of one or more pumps. As part of the verification operation, the control device 40 obtains the current CRP values ​​(first and second measurements) from the medical fluid signals S1, S1' and evaluates the current CRP values ​​to detect abnormal deviations. If an abnormal deviation is detected, the control device 40 may take targeted measures, such as generating an alarm on its UI device (not shown), or performing a calibration phase to determine an updated calibration function to replace the currently used calibration function. Targeted measures may also include actuating the valve assembly 15 to shunt the medical fluid into the shunt line 16, at least if the magnitude of the abnormal deviation is large, for example, relative to a threshold. In one example, control device 40 can evaluate the current CRP value by running a transformation function on the CRP value from signal S1, thereby calculating the current transformed CRP value, and evaluating the current transformed CRP value relative to the current CRP value from signal S1'. If the difference between these CRP values ​​exceeds a threshold, an abnormal deviation can be detected.

[0071] Figure 5A An example of the aforementioned disposable device 1a (also referred to herein as a "disposable component") is shown. Disposable component 1a may be an integral assembly as shown, or it may be an assembly of connectable sub-components. Disposable component 1a is configured as a dedicated accessory for installation on a machine. In the example shown, disposable component 1a includes a water supply line 11, a container 3a, a main fluid line 12, a connecting fluid line 13, a connector 13b, a CRP sensor 20, and a branch line 16. Connector 11a is disposed at the end of line 11 to connect to the water supply device 10, connector 13a is disposed at the end of line 13 to connect to the container 3b, connector 12a is disposed at the end of line 12 to connect to the receiving device 30, and connector 16a is disposed at the end of line 16 to connect to the CRP sensor 20'. The arrangement of connector 13a allows the operator to remove container 3b when it is empty and reattach a new container 3b filled with fluid F2. The disposable part 1a is discarded after use, for example, after a single treatment is completed, after the predetermined maximum usage time is reached, or whenever a new patient is to be treated.

[0072] In disposable component 1a, the fluid line may be defined by plastic tubing. As described above, pumps P1 and P2 may be peristaltic pumps, which engage with the outside of the tubing to create a moving compression on the tubing, thereby forcing fluid to move along the tubing. Typically, to facilitate the use of peristaltic pumps, the tubing is provided with a dedicated engagement portion (also called a pump section) configured to engage with the compression element of the peristaltic pump. Figure 5A In the middle, pump sections 4a and 4b are configured to work with pumps P1 and P2 ( Figure 1 ) join.

[0073] Disposable component 1a can be detachably attached to Figure 5B The machine 1b is schematically shown in the diagram. In the illustrated example, machine 1b includes pumps P1 and P2, which can be engaged with pump sections 4a and 4b of disposable component 1a. Machine 1b also includes a valve assembly 15, which can be engaged with fluid lines in disposable component 1a. In the illustrated example, machine 1b also includes scales 2a and 2b, which are configured to hold corresponding containers 3a and 3b. Machine 1b also includes a control device 40. Figure 5B In the example, machine 1b also includes CRP sensor 20', although alternative mounting methods are also possible (described below). As shown by the dashed lines, machine 1b may include additional scales 2c-2d, pumps P3-P6, and valve assembly 15a. Machine 1b may be a dialysis machine, or it may be a dedicated machine for generating medical fluids used in RRT (performed by a separate dialysis machine).

[0074] It should be recognized that the operating system 1 generates medical fluid online. Furthermore, the medical fluid is generated within the disposable component 1a. This means that an existing machine (e.g., a dialysis machine) can be configured to generate dialysis fluid online by attaching the correctly configured disposable component 1a and reconfiguring the control unit 40 (e.g., by updating its control program).

[0075] System 1 can be configured to generate medical fluids by mixing any number of component fluids. Figure 6 An example system 1 configured to mix three component fluids F1, F2, and F3 is shown. The following description will focus on... Figure 1 The differences between the two systems are as follows. In some embodiments, the first fluid F1 is water, while the second fluid F2 and the third fluid F3 are different liquid concentrates. The third fluid F3 is contained in a container 3c, which is arranged on a scale 2c. The scale 2c is configured to provide a weight signal S4. Figure 6System 1 includes a connecting fluid line 14 extending from container 3c to a connector 14b on the main fluid line 12. Connector 14b may be similar to connector 13b. System 1 is configured to allow the F3 flow to merge with a mixed flow of F1 and F2 in the main fluid line 12 within connector 14b and downstream thereafter, forming a mixture. Pump assembly 4 of the system includes pumps P1, P2, and P3. Pump P3 is arranged in the connecting fluid line 14 to define the F3 flow. Pump P3 responds to a control device 40 (… Figure 1 The pump P3 operates by generating a control signal C5. Therefore, the pump P3 is operable to control the amount of F3 mixed in F1 and F2 within the main fluid line 12. A connector 14a is disposed at the end of the line 14 for detachable connection to the container 3c. An additional CRP sensor 20a is disposed in the main fluid line 12 between connectors 13b and 14b. The additional CRP sensor 20a is configured to output a measurement signal S1a indicating parameters related to the composition of the flowing fluid. The measurement signal S1a is provided to the control device 40. Figure 1 The additional CRP sensor 20a can be disposable. Therefore, the connecting line 14 and the additional sensor 20a can be included in... Figure 5A The disposable component 1a, while the pump P3 may be included in Figure 5B In machine 1b.

[0076] when Figure 6 During the production phase of system 1, the signal S1 from sensor 20 is used to control pump P3 to achieve the target CRP value (“final CRP target”) of the medical fluid, which is consistent with... Figure 4 Similarly. Furthermore, the signal S1a from sensor 20a is used to control pump P2 to achieve a target CRP value (“intermediate CRP value”) for the intermediate mixture of F1 and F2, which is consistent with... Figure 4 Similarly. Furthermore, as understood from the previous description, pump P1 can or can not be controlled by feedback control to generate the target flow rate.

[0077] Figure 7 It is an operation Figure 6 A flowchart of example method 700 in System 1. (Relative to...) Figure 2AIn method 200, steps 701-707 correspond to step 201, steps 708-709 correspond to step 202, and steps 710-711 correspond to step 203. Method 700 is configured to minimize waste of component fluids F1, F2, and F3 by performing a calibration phase while sequentially mixing component fluids F1, F2, and F3 in proportions matching their proportions in the medical fluid. In step 701, valve assembly 15 is operated to direct fluid from main fluid line 12 to branch line 16, thereby directing it to discharge section 17. No fluid flows to receiving device 30. In step 702, pump P1 is started and operated to generate a target flow rate, which is maintained throughout the calibration phase. Thus, F1 is pumped as the first or initial test fluid through sensors 20a, 20, and 20'. The target flow rate can be the same as the target flow rate of the medical fluid in subsequent generation phases. This ensures a smooth transition from the calibration phase to the generation phase. During the calibration phase, pump P1 may or may not be operated via feedback control. In step 703, the corresponding CRP values ​​are obtained from signals S1a, S1, and S1', thereby obtaining the first SDP of sensors 20a, 20' and the first SDP of sensors 20, 20'. As mentioned above, the corresponding CRP values ​​can be obtained as the average of multiple signal values ​​in the corresponding signals. Step 703 can be performed after verifying that the time variability of signals S1a, S1, and S1' is below a variability threshold to avoid transient effects. In step 704, pump P2 is started and operated via feedback control based on signal S1' to achieve a first target CRP value. The first target CRP value is the same as the intermediate CRP value used in the generation phase. Thus, the intermediate mixture of F1 and F2 is pumped through sensors 20a, 20, and 20' as the second test fluid. In step 705, similar to step 703, the corresponding CRP values ​​are obtained from signals S1a, S1, and S1', thereby obtaining the second SDP of sensors 20a and 20' and the second SDP of sensors 20 and 20'. In step 706, pump P3 is started and operated via feedback control based on signal S1' to achieve the second target CRP value. The second target CRP value is the same as the final CRP target used in the generation stage. In steps 704 and 706, pump P2 is operated to generate the same flow rate. Thus, in step 706, the final mixture of F1, F2, and F3 is pumped through sensors 20 and 20' as the third test fluid. The composition of the final mixture is the same as the composition of the medical fluid to be generated. When method 700 transitions from step 704 to step 706, the speeds of pumps P1 and P2 can be fixed. If the speed of pump P1 is allowed to vary, the speed of pump P2 can be controlled to keep the relationship between the speeds of pumps P1 and P2 in step 706 the same as in step 704.In another embodiment, the speed of pump P2 is controlled based on the measured or estimated flow rate generated by pump P2 (e.g., based on the output signal of a flow meter (not shown) or the weight signal S3). In another embodiment, the speed of pump P2 is controlled to maintain a first target CRP value in the signal S1a from sensor 21a. In step 707, the corresponding CRP values ​​are obtained from signals S1 and S1', thereby obtaining a third SDP for sensors 20, 20'. In step 708, a first transition function of sensor 20 is determined using the first SDP, second SDP, and third SDP of sensors 20, 20' obtained in steps 703, 705, and 707. Reference. Figure 3 M1-M3 can correspond to the first SDP to the third SDP. In step 709, the second conversion function of sensor 20a is determined by using the first and second SDPs of sensors 20a and 20' obtained in steps 703 and 705. (See reference...) Figure 3 M1 and M2 can correspond to the first SDP and the second SDP. In step 710, the flow control procedure for the generation phase is initiated. Pump P1 is operated to generate the target flow rate of the medical fluid, pump P2 is operated by feedback control based on signal S1a and by using a second conversion function, and pump P3 is operated by feedback control based on signal S1 and by using a first conversion function. In step 711, valve assembly 15 is operated to guide the medical fluid along the main fluid line 12 to outlet 12a.

[0078] Those skilled in the art should understand that method 700 can be extended to a larger number of component fluids. Such a system may include a correspondingly increased number of disposable CRP sensors. Method 700 is also applicable, for example, in… Figure 1 In system 1, two component fluids F1 and F2 are mixed.

[0079] It is important to note that, for example, in Figure 6 In System 1, if one of pumps P2 and P3 and pump P1 operate at a fixed pumping rate during the generation phase, the additional CRP sensor 20a can be omitted. If one of pumps P2 and P3 is controlled based on another measurement signal during the calibration and / or generation phases, the additional sensor 20a can also be omitted. In some embodiments, P2 or P3 is controlled by feedback control based on the instantaneous weight change of the respective containers 3b and 3c relative to container 3a. For example, the operation of pump P2 can be controlled to achieve a target relationship between the instantaneous weight changes of containers 3b and 3a. Therefore, this feedback control is performed based on weight signals S3 and S2. The target relationship can be determined as part of the calibration phase. Figure 7In the example, when the pump P2 has been controlled to generate a first target CRP value at sensor 21' by determining the weight change per unit time in signal S2 and the weight change per unit time in signal S3, the target relationship can be determined in step 705. The weight change per unit time can be determined by running any conventional differential algorithm on the corresponding signals S2 and S3.

[0080] Weight-based feedback control is predicated on machine 1b ( Figure 5B A scale is provided in the system. Even if a scale is available, implementing weight-based feedback control to, for example, control the quantitative addition of liquid concentrate generated online from dry concentrate by system 1 may be difficult or undesirable. Figure 12 An example assembly of container 3b containing dry concentrate F2' is shown. Dry concentrate F2' is soluble in water and can be in powder or granule form. In the example shown, container 3b is assembled in a manner similar to... Figure 1 or Figure 6 The container 3b in System 1 is similar. Container 3b is detachably connected to connector 13a on fluid line 13 and connector 18a on water supply line 18. Water supply line 18 may extend to container 3a or water supply device 10. Pump P2 is arranged on fluid line 13 to draw liquid concentrate F2 from container 3b (optionally, via regulating unit 19). Regulating unit 19 may be configured to ensure that liquid concentrate F2 is supplied with a suitable composition. Regulating unit 19 may include conventional equipment for mixing, adding additional water, recirculation, etc. It should be recognized that, in Figure 12 In the installation method, at least when generating liquid concentrate F2 on demand, it may be difficult to achieve weight-based control.

[0081] In some embodiments, system 1 is configured to perform weight-based control of the pump to quantitatively add liquid concentrate from a pre-filled container, and CRP-based control of the pump to quantitatively add liquid concentrate formed by diluting the dry concentrate. This can be based on... Figure 2A or Figure 6 The methods in the document execute CRP-based control.

[0082] Figure 8 This is a flowchart of an example method 800 for configuring and operating the system to generate medical fluids. Method 800 can be performed by a control device in any system described herein. In step 801, the user (operator) installs disposable components onto the machine, properly engaging it with scales, pumps, valve assemblies, etc. This machine can be a dialysis machine or any other suitably equipped machine. In step 802, the user connects the shunt line 16 to fluid communication with the reusable CRP sensor 20'. Then, the procedure is performed... Figure 2AMethod 200 generates a medical fluid. At a certain point, method 200 is terminated, and step 803 is executed to initiate a procedure to ensure the reusability of the CRP sensor 20'. An example of step 803 is described below. Upon completion of step 803, step 804 is executed to allow the user to remove and discard a disposable component from the machine. Steps 801-804 may include providing user instructions on a UI device (not shown) to cause the user to perform one or more actions. Therefore, in the context of this disclosure, causing the user to perform an action is equivalent to outputting instructions to the user to perform an action.

[0083] Step 803 may vary depending on the location and degree of integration of the reusable CRP sensor 20' within the system.

[0084] In some embodiments, a reusable CRP sensor 20' is integrated into the water supply device 10. Figure 9 An example of such a water supply device 10 is shown. The operation of the water supply device 10 is controlled by an internal controller (not shown). The device 10 includes a water treatment unit 90 operable to treat influent water to produce purified water for medical fluids. The water treatment unit 90 can be configured to purify the influent water using any available technology, such as a sedimentation filter, activated carbon filter, resin bed, ultrafiltration (UF), reverse osmosis (RO), nanofiltration, electro-deionization (EDI), capacitive deionization (CDI), or any combination thereof. The device 10 includes a water supply line 91 extending from an inlet connector 91a to an outlet connector 91b. In operation, a tap water source can be connected to the inlet connector 91a, and disposable components (…) can be… Figure 1 and Figure 6 The terminal connector 11a is connected to the outlet connector 91b. The device 10 also includes an auxiliary fluid line 92 that extends from the inlet connector 92a to the outlet connector 92b via a reusable sensor 20'. In operation, disposable components ( Figure 1 , Figure 5A and Figure 6The terminal connector 16a of the device is connected to the inlet connector 92a, and a fluid line (not shown) extending to the outlet 17 can be connected to the outlet connector 92b. The device 10 also includes a cleaning unit 93 operable to perform cleaning operations on the reusable sensor 20' and optionally the water treatment unit 90. Cleaning operations may include rinsing and / or disinfection. As used herein, rinsing involves flushing the sensor 20' with a fluid to remove deposits, particles, etc. The fluid can be any liquid, including water, and may or may not include cleaning agents such as detergents, descaling agents, etc. As used herein, disinfection refers to the process of preventing microbial growth in the sensor 20' and may involve heat treatment, flushing with disinfectants or sterilizing agents, etc. It should be understood that in the cleaning operation, not only the sensor 20' is treated, but also the connecting fluid path. The device 10 also includes an I / O unit 94 operable to receive control signal C4 ( Figure 1 and Figure 6 In operation, the I / O unit 94 is connected to the control device 40 via wired or wireless means. In one embodiment of step 803, the control device 40 transmits a control signal C4 to the water supply device 10 to initiate the cleaning operation. In another embodiment of step 803, the control device 40 allows the user to initiate the cleaning operation, for example, by pressing a dedicated button (not shown) on the device 10, via its UI device.

[0085] If the reusable CRP sensor 20' is connected to the main fluid line 12 ( Figure 1 and Figure 6 If the sensors are appropriately spaced, the risk factors for microbial growth in the sensor 20' are reduced. Therefore, the need for disinfection is reduced or even eliminated. However, since the sensor 20' is reused in multiple single treatments, regular cleaning can be performed to ensure its long-term proper functioning. For example, flushing can be performed to reduce dirt, such as scale, deposits, etc. Whenever microorganisms are present, they can move along the branch line 16 into the main fluid line 12. Figure 1 and Figure 6 When there is a risk of infection, it may be important to perform disinfection to mitigate the growth of microorganisms within the sensor 20'. It should be recognized that cleaning procedures may involve rinsing and / or disinfection, and rinsing and disinfection may be performed at different time intervals. Furthermore, it is conceivable to perform cleaning procedures at a lower frequency compared to performing them after each individual treatment.

[0086] In some embodiments, the reusable CRP sensor 20' is integrated into machine 1b (see [link]). Figure 5B If machine 1b includes an integrated cleaning unit for cleaning sensor 20', then control device 40 can autonomously initiate the cleaning operation in step 803.

[0087] In some embodiments, the reusable CRP sensor 20' is included in a separate device (not shown), which is separate from the machine 1b and the water supply device 10. This reusable CRP sensor 20' may (but is not required to) be connected to the control device 40 for electronic transmission of the output signal S1' (see [link to relevant documentation]). Figure 1 Conversely, the measurement data generated by sensor 20' can be manually entered into control device 40 by an operator via a data input interface, or it can be electronically transmitted to control device 40 using a scanner. For example, a scanner can be operated to scan test results from sensor 20' that are printed or displayed, for example, in plain text or machine-readable code.

[0088] Figures 10A to 10B An example of a reusable CRP sensor 20' is shown, which is arranged inside a device 1000, which may be a machine 1b, a water supply device 10, or one of the aforementioned individual devices. Here, it is assumed that the device 1000 does not have the function of rinsing or disinfecting the sensor 20'. The sensor 20' defines an internal channel 20" and is configured to measure the CRP value of the fluid in the channel 20". The device 1000 defines an inlet port 21a and an outlet port 21b in fluid communication with the channel 20" on a flow path 21. Although not shown, the device 1000 includes an I / O unit for transmitting measurement data to a control device 40. Figure 10A It shows in Figure 8 The first connection state is achieved in step 802. In the first connection state, sensor 20' is in fluid communication with the shunt line 16. In the illustrated example, the shunt line 16 is connected to the inlet port 21a via line segment 16'. Specifically, line segment 16' includes terminal connector 16a1 and terminal connector 16a2, terminal connector 16a1 being configured to connect to terminal connector 16a on the shunt line 16, and terminal connector 16a2 being configured to connect to the inlet port 21a. Furthermore, line segment 16' is connected to the outlet port 21b via terminal connector 16a3 and extends to the discharge section 17. Figure 10B It shows in Figure 8The second connection state is achieved in step 803. In the second connection state, sensor 20' is encapsulated in a closed loop and filled with a dedicated fluid configured to extend the lifespan of sensor 20'. For example, the dedicated fluid may be an antibacterial fluid. Antibacterial fluids include antibacterial agents, which are biological or chemical agents (also known as bactericides) that inhibit bacterial growth or even kill bacteria. Therefore, in the second connection state, sensor 20' remains in an environment that prevents bacterial growth. To achieve the second connection state, step 803 may include operating system 1 to deliver the dedicated fluid from the supply section to the branch line 16 and through sensor 20'. When sensor channel 20" is considered to contain dedicated fluid, step 803 includes instructing the user to disconnect line 16' from line 16, disconnect line 16" from port 21b, and attach terminal connector 16a1 to port 21b. Through this manipulation, the dedicated fluid is retained within sensor 20'. In some embodiments, the filling of sensor channel 20" is monitored based on the output signal (i.e., S1') of sensor 20'. Figures 10A to 10B The manipulation involves using components with reusable disposable parts to fluidly connect ports 21a and 21b. When method 800 is executed later (at which point device 1000 is in a second connection state), step 802 may include instructing the user to adjust the connection according to the first connection state ( Figure 10A Before connecting a new disposable part to device 1000, disconnect and discard pipeline segment 16'.

[0089] The dedicated fluid may be different from fluids F1, F2, and F3, and may be delivered to the branch line 16 from a separate source via a dedicated pump. However, in some embodiments, the dedicated fluid consists of at least one liquid concentrate included in the medical fluid.

[0090] Figures 10A to 10B This is just one example of how sensor 20' can be manipulated to retain the dedicated fluid within sensor 20'. For example, ports 21a and 21b can be sealed in other ways to retain the dedicated fluid. Furthermore, if sensor 20' is integrated into machine 1b or water supply device 10, the technique for retaining the dedicated fluid within sensor 20' in step 803 is also applicable.

[0091] Figure 11 This is a flowchart of example method 1100, which can be executed during the generation of medical fluid in system 1. (See also...) Figure 1 System 1 describes method 1100, and method 1100 is also applicable to Figure 6In System 1, when an operational interruption of the receiving device 30 is detected (step 1101), valve assembly 15 is operated to direct medical fluid to discharge section 17 (step 1102). Here, it is assumed that the interruption prevents device 30 from receiving medical fluid. Control device 40 can detect the interruption based on the output signal from receiving device 30 or a sensor (e.g., a pressure sensor (not shown) in line 12). In conjunction with step 1102, to minimize waste of liquid concentrate F2, the speed of pump P2 is reduced at least, but pump P2 is not stopped (step 1103). Therefore, both pumps P1 and P2 remain operational. When the resumption of operation of receiving device 30 is detected (step 1104), the speeds of pumps P1 and P2 are controlled to meet the target flow rate and achieve the final CRP target at sensor 20 (step 1105). In conjunction with step 1104, valve assembly 15 is operated to direct medical fluid toward receiving device 30 (step 1106). It is conceivable to implement step 1104 with a timeout function, which would cause system 1 to be shut down if no recovery operation is detected within a preset time from step 1101.

[0092] Through method 1100, pumps P1 and P2 remain operational during the interruption of receiving device 30. If pumps P1 and P2 stop, the hysteresis effect may require control device 40 to enter a calibration phase. It is conceivable that in step 1103, pumps P1 and P2 operate at a reduced rate. Furthermore, while operating at a reduced rate, pumps P1 and P2 can be controlled based on signal S1' to maintain the target composition of the medical fluid. Thus, medical fluid is still generated in step 1103, although at a reduced flow rate.

[0093] In some embodiments, when the operation of the receiving device 30 is interrupted, both pumps P1 and P2 stop, and when the operation of the receiving device 30 resumes, both pumps P1 and P2 restart at their previous speeds. This embodiment is also possible for pumps that do not exhibit the aforementioned hysteresis effect.

[0094] This disclosure is not limited to the examples given above. For example, the container 3a for storing the first fluid F1 (typically water) is optional. Instead, water can be supplied directly from the water supply device 10 to the main fluid line 12. Furthermore, the installation and use of a scale is optional. Additionally, the scale can be used for other purposes, such as monitoring and / or controlling ultrafiltration. In some embodiments, F1 contains more than just water.

[0095] In some embodiments, some or all of the fluid lines in the disposable component are configured as channels within an integrated housing. The pump and / or valve assembly may or may not be integrated into the housing. If integrated, the pump may be implemented, for example, as a diaphragm pump or a roller pump.

[0096] In an alternative, containers 3b and 3c can be refilled via fluid connection to the corresponding liquid concentrate source.

[0097] In system 1 shown in the figure, pump P1 is located in the main fluid line 12 downstream of connector 13b (and connector 14b, if present). Therefore, the first pump P1 not only draws fluid F1 from container 3a but also defines the flow rate of the medical fluid (“main flow rate”). This provides the technical advantage of simplifying the adjustment of the main flow rate. However, in some embodiments, pump P1 may instead be located upstream of connectors 13b and 14b.

[0098] Any commercially available concentrate may be used in System 1 as described herein.

[0099] In some embodiments, the dialysis fluid for CRRT treatment of AKI patients is generated by mixing at least one concentrate with water. In non-limiting examples, such dialysis fluid includes bicarbonate, sodium, potassium, calcium, magnesium, phosphate, glucose, acetate, and chloride. In one example, an alkaline concentrate and an electrolyte concentrate may be mixed with water to form the dialysis fluid. For example, the alkaline concentrate may be an alkaline bicarbonate solution, while the electrolyte concentrate may be an acidic glucose electrolyte solution.

[0100] In some embodiments, the dialysis fluid for peritoneal dialysis (PD) is generated by mixing at least one concentrate with water. Example components of PD concentrates, mixed alone or in combination with water, are disclosed in US2018 / 0021501 and WO2017 / 193069, which are incorporated herein by reference.

[0101] In some embodiments, the dialysis fluid for treating CKD patients by hemodialysis, hemofiltration, or hemodiafiltration is produced by mixing a single concentrate with water at a volume dilution ratio of 10-50. In a non-limiting example, the single concentrate includes lactate, sodium, potassium, calcium, magnesium, glucose, and chloride. Such concentrates are commercially available, for example, for the PureFlow SL system from NxStage. Alternatively, the dialysis fluid can be produced by mixing two concentrates with water. For example, a bicarbonate concentrate and an acid concentrate can be mixed with water at a dilution ratio of 10-50. Such concentrates are commercially available and are known in the art. In a non-limiting example, the bicarbonate concentrate includes bicarbonate, while the acid concentrate includes sodium, potassium, calcium, magnesium, glucose, acetate, and chloride. In some acid concentrates, the acetate is replaced or supplemented with another acid (e.g., citric acid or hydrochloric acid).

[0102] While the subject matter of this disclosure has been described in conjunction with embodiments that are now considered to be the most practical, it should be understood that the subject matter of this disclosure is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0103] Furthermore, although the operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring the operations to be performed in the specific order shown or in sequential order, or to perform all the operations shown in order to achieve the desired result.

[0104] The following sections record terms to summarize some of the aspects and embodiments disclosed above.

[0105] C1. A system for generating a medical fluid for renal replacement therapy, the system comprising: a first flow path (12) for receiving and mixing at least two fluids to form the medical fluid; a pump assembly (4) for pumping the at least two fluids through the first flow path (12); a first sensor (20, 20a) disposed in the first flow path (12) to provide a first signal (S1, S1a) indicating a component-related parameter; a valve assembly (15) operable to selectively open a channel from the first flow path (12) to a second flow path (16); a second sensor (20') disposed in the second flow path (16) to provide a second signal (S1') indicating the component-related parameter; and a control device (40) configured to operate the valve assembly (15) and the pump assembly (4) during a calibration phase (CP) to pump at least one of the at least two fluids through the first flow path (12). A fluid is delivered to the first sensor (20, 20a) and the second sensor (20'); during the calibration phase, a conversion function is determined based on the first signal (S1, S1a) and the second signal (S1'), the conversion function being used to convert the measurement value in the first signal (S1, S1a) into the measurement value in the second signal (S1'); and in the production phase (PP), the valve assembly (15) and the pump assembly (4) are operated to pump the at least two fluids through the first flow path (12) to provide the medical fluid at the outlet (12a), wherein at least one pump (P2; P3) in the pump assembly (4) is controlled based on a conversion measurement value, the conversion measurement value being given by performing the conversion function on the measurement value in the first signal (S1; S1a) from the first sensor (20; 20a) during the production phase (PP).

[0106] C2. The system according to C1, wherein the first sensor (20, 20a) is a disposable component, and the second sensor (20') is a reusable component.

[0107] C3. The system according to C1 or C2, wherein the second sensor (20') is configured to remain in the system and to repeat the calibration phase when the first sensor (20, 20a) is discarded and replaced with a new first sensor (20, 20a), wherein repeating the calibration phase produces an updated conversion function for converting the measured value in the first signal (S1, S1a) of the new first sensor (20, 20a) into the measured value in the second signal (S1') of the second sensor (20').

[0108] C4. The system according to any of the preceding clauses, wherein the second sensor (20') has higher accuracy than the first sensor (20, 20a).

[0109] C5. A system according to any of the preceding clauses, comprising a machine (1b) and a disposable device (1a) detachably coupled to said machine (1b), wherein said machine (1b) comprises said pump assembly (4) and said valve assembly (15), and wherein said disposable device (1a) defines a first flow path (12) and a second flow path (16), and wherein said first sensor (20, 20a) is included in said disposable device (1a).

[0110] C6. The system according to any of the preceding clauses, wherein the control device (40) is configured during the calibration phase (CP) to: operate the pump assembly (4) to generate a group of test fluids from the at least two fluids; operate the pump assembly (4) and the valve assembly (15) to deliver a corresponding test fluid from the group of test fluids to the first sensor (20, 20a) and the second sensor (20'); obtain a first measurement value of the corresponding test fluid from the first signal (S1, S1a); obtain a second measurement value of the corresponding test fluid from the second signal (S1'); and determine the conversion function based on the first and second measurement values ​​of the corresponding test fluids.

[0111] C7. The system according to C6, wherein at least one of the group of test fluids comprises a mixture of the at least two fluids.

[0112] C8. The system according to C7, wherein the control device (40) is configured during the calibration phase (CP) to operate the pump assembly (4) to generate the at least one test fluid to achieve a target value of the second signal (S1') from the second sensor (20').

[0113] C9. The system according to any one of C6-C8, wherein one of the test fluids in the group of test fluids is the medical fluid.

[0114] C10. The system according to any one of C6-C9, wherein the control device (40) is configured during the calibration phase (CP) to operate the pump group (4) to generate the group of test fluids by providing a first fluid (F1) of the at least two fluids as an initial test fluid, and sequentially adding other fluids of the at least two fluids to the initial test fluid to generate a corresponding test fluid sequence, until all fluids of the at least two fluids have been added to the initial test fluid.

[0115] C11. The system according to C10, wherein the first fluid (F1) is water, and wherein each of the other fluids is added in a proportion equal to that of each of the other fluids in the medical fluid.

[0116] C12. The system according to any one of C6-C11, wherein the control device (40) is configured to determine the conversion function by fitting a predetermined function to a first and a second measurement of the group of test fluids.

[0117] C13. The system according to any of the preceding clauses, wherein the first sensor (20, 20a) is located upstream of the valve assembly (15) in the first flow path (12) such that when the valve assembly (15) is operated to open the passage from the first flow path (12) to the second flow path (16), the first sensor (20, 20a) and the second sensor (20') are fluidly connected in series.

[0118] C14. The system according to any of the preceding clauses, wherein the control device (40) is configured during the generation phase to: intermittently operate the valve assembly (15) to open the channel to the second flow path (16) and direct the medical fluid to the second sensor (20'); obtain a current first measurement value of the medical fluid from the first signal (S1, S1a); obtain a current second measurement value of the medical fluid from the second signal (S1'); evaluate the current first measurement value and the current second measurement value to detect a deviation; and take targeted measures when the deviation is detected.

[0119] C15. The system according to C14, wherein the control device (40) is configured to: execute the conversion function on the current first measurement value to generate a current converted measurement value; and evaluate the current second measurement value and the current converted measurement value to detect the deviation.

[0120] C16. The system according to C14 or C15, wherein the targeted measures include generating an alarm or performing the calibration phase (CP) to determine at least one of the updated conversion functions.

[0121] C17. The system according to any of the preceding clauses, wherein the control device (40) is configured during the generation phase (PP) to monitor the speed of the pumps in the pump set (4) to detect changes indicating operational errors.

[0122] C18. In any of the preceding clauses, the at least two fluids comprise liquid concentrates.

[0123] C19. The system according to C18, wherein the system is configured to generate the liquid concentrate from the dry concentrate.

[0124] C20. The system according to any of the preceding clauses, wherein the control device (40) is configured during the generation phase (PP) to control the pump assembly (4) to generate the medical fluid at a target flow rate while maintaining the conversion measurement at a target value for the component-related parameter.

[0125] C21. The system according to any of the preceding clauses, wherein the control device (40) is operable to initiate a procedure for ensuring the reuse of the second sensor (20').

[0126] C22. The system according to C21, wherein the procedure for ensuring reuse includes at least one of the following: a) operating a fluid supply device (10; 1b; 1000) including the second sensor (20') to perform rinsing and / or disinfecting the second sensor (20'); or b) delivering a dedicated fluid through the second flow path (16) into the second sensor (20'), and having the user disconnect the second flow path (16) from the second sensor (20') and manipulate the second sensor (20') to retain the dedicated fluid within the second sensor (20').

[0127] C23. The system according to C22, wherein the dedicated fluid is antibacterial.

[0128] C24. The system according to C22 or C23, wherein the system is configured to provide the dedicated fluid based on at least one of the at least two fluids.

[0129] C25. A system according to any of the preceding clauses, wherein the at least two fluids include a first fluid (F1) provided by a first source (3a) and a second fluid (F2) provided by a second source (3b), wherein the pump assembly (4) includes a first pump (P1) and a second pump (P2), the first pump (P1) being configured to deliver the first fluid (F1) from the first source (3a) into the first flow path (12), and the second pump (P2) being configured to deliver the second fluid (F2) from the second source (3b) into the first flow path (12) to generate a mixture of the first fluid (F1) and the second fluid (F2) in the first flow path (12).

[0130] C26. The system according to C25, wherein the control device (40) is configured in the generation stage (PP) to operate the first pump (P1) and the second pump (P2) to pump the first fluid (F1) and the second fluid (F2) through the first flow path (12) to provide the mixture in the first flow path (12), wherein the second pump (P2) is controlled based on the conversion measurement.

[0131] C27. The system according to C25 or C26, wherein a connecting line (13) extends from the second source (3b) to a connector (13b) on the first flow path (12), wherein the second pump (P2) is arranged within or on the connecting line (13) to deliver the second fluid (F2) from the second source (3b) into the first flow path (12), and wherein the first pump (P1) is arranged between the connector (13b) and an outlet (12a) for the medical fluid within or on the first flow path (12).

[0132] C28. The system according to C27, wherein the control device (40) is configured in the generation phase (PP) to control the first pump (P1) to generate the medical fluid at a target flow rate.

[0133] C29. The system according to any one of C25-C28 further includes a first scale (2a) and a second scale (2b), wherein the first source is a first container (3a) arranged on the first scale (2a), wherein the second source is a second container (3b) arranged on the second scale (2b), wherein the control device (40) is configured in the calibration phase (CP) and / or the generation phase (PP) to partially control the pump assembly (4) based on the weight changes of the first container (3a) and the second container (3b) given by the first output signal (S2) of the first scale (2a) and the second output signal (S3) of the second scale (2b).

[0134] C30. The system according to C29, wherein the control device (40) is configured during the generation phase (PP) to monitor the first output signal (S2) and the second output signal (S3) to detect changes indicating operational errors.

[0135] C31. The system according to any of the preceding clauses, wherein the outlet (12a) is connected to the receiving device (30), wherein the control device (40) is configured during the generation phase (PP) to: detect an operational interruption of the receiving device (30) while the medical fluid is being guided along the first flow path (12) to the outlet (12a); and upon detecting the operational interruption, to operate the valve assembly (15) to close the first flow path (12) and open a passage to the second flow path (16), and to reduce the pumping speed of at least one pump in the pump assembly (4).

[0136] C32. The system according to C31, wherein the control device (40) is further configured to operate the pump assembly (4) to generate the medical fluid when the operation interruption is detected.

[0137] C33. A system according to any of the preceding clauses, wherein the component-related parameters represent conductivity, resistivity, concentration of one or more solutes, or pH.

[0138] C34. The system according to any of the preceding clauses, wherein the medical fluid is a processing fluid used in extracorporeal blood therapy or peritoneal dialysis.

[0139] C35. A control method for operating a system according to any of the preceding clauses, the method comprising: operating (201) the valve assembly and the pump assembly during a calibration phase to deliver at least one of the at least two fluids to a first sensor and a second sensor; determining (202) a conversion function based on the first signal and the second signal during the calibration phase, the conversion function being used to convert a measurement in the first signal to a measurement in the second signal; and operating (203) the valve assembly and the pump assembly during a generation phase to pump the at least two fluids through the first flow path to provide the medical fluid at the outlet; wherein the operation (203) during the generation phase includes controlling (203c) at least one pump in the pump assembly based on a converted measurement value, the converted measurement value being given by performing the conversion function on a measurement value from the first signal of the first sensor during the generation phase.

[0140] C36. A computer-readable medium comprising computer instructions that, when executed by a processor (41), cause the processor (41) to perform the method according to C35.

[0141] C37. A disposable device for use in a system according to any one of C1-C34, the disposable device comprising: a first flow path (12), a first sensor (20) and a second flow path (16), the second flow path (16) extending from the first flow path (12) to a detachable fluid connector (16a) for fluidly connecting to the second sensor (20').

Claims

1. A system for generating a medical fluid for renal replacement therapy, the system comprising: a first flow path (12) for receiving and mixing at least two fluids to form the medical fluid; a pump group (4) for pumping the at least two fluids through the first flow path (12); a first sensor (20, 20a) arranged in the first flow path (12) to provide a first signal (SI, Sla) indicative of a composition-related parameter; a valve group (15) operable to selectively open a passage from the first flow path (12) to a second flow path (16); a second sensor (20') arranged in the second flow path (16) to provide a second signal (SI') indicative of the composition-related parameter; and a control device (40) configured to: operate the valve group (15) and the pump group (4) in a calibration phase (CP) to deliver at least one of the at least two fluids to the first sensor (20, 20a) and the second sensor (20'); determine, during the calibration phase, a conversion function based on the first signal (SI, Sla) and the second signal (SI') for converting a measured value in the first signal (SI, Sla) to a measured value in the second signal (SI'); and in a production phase (PP), operate the valve group (15) and the pump group (4) to pump the at least two fluids through the first flow path (12) to provide the medical fluid at an outlet (12a), wherein at least one pump (P2; P3) in the pump group (4) is controlled based on a converted measured value given by performing the conversion function on a measured value in the first signal (SI; Sla) from the first sensor (20; 20a) during the production phase (PP). The first sensor (20, 20a) is a disposable component, while the second sensor (20') is a reusable component.

2. The system of claim 1, wherein, The second sensor (20') is configured to remain in the system and to be used for repeating the calibration phase when the first sensor (20, 20a) is discarded and replaced by a new first sensor (20, 20a), wherein repeating the calibration phase results in an updated conversion function for converting a measured value in a first signal (SI, Sla) of the new first sensor (20, 20a) to a measured value in a second signal (SI') of the second sensor (20').

3. The system of claim 1 or 2, wherein, The second sensor (20') has a higher accuracy than the first sensor (20, 20a).

4. The system of any preceding claim, wherein, The machine (lb) comprises the pump group (4) and the valve group (15), and wherein the disposable device (la) defines the first flow path (12) and the second flow path (16), and wherein the first sensor (20, 20a) is comprised in the disposable device (la).

5. The system of any preceding claim, comprising a machine (1 b) and a disposable device (1 a) removably engageable with the machine (1 b), wherein, ​ 6. The system of any preceding claim, wherein, The control device (40) is configured, in the calibration phase (CP), to operate the pump group (4) to generate a set of test fluids from the at least two fluids; operate the pump group (4) and the valve group (15) to deliver respective test fluids of the set of test fluids to the first sensor (20, 20a) and the second sensor (20'); obtain a first measurement of the respective test fluid from the first signal (S1, S1a); obtain a second measurement of the respective test fluid from the second signal (S1'); and determine the conversion function based on the first and second measurements of the respective test fluid.

7. The system of claim 6, wherein, At least one test fluid of the set of test fluids comprises a mixture of the at least two fluids.

8. The system of claim 7, wherein, The control device (40) is configured, in the calibration phase (CP), to operate the pump group (4) to generate the at least one test fluid to achieve a target value of the second signal (S1 ') from the second sensor (20').

9. The system of any one of claims 6-8, wherein, One test fluid of the set of test fluids is the medical fluid.

10. The system of any one of claims 6-9, wherein, The control device (40) is configured, in the calibration phase (CP), to operate the pump group (4) to generate the set of test fluids by providing a first fluid (F1) of the at least two fluids as an initial test fluid and sequentially adding other fluids of the at least two fluids to the initial test fluid to generate a corresponding sequence of test fluids until all fluids of the at least two fluids have been added to the initial test fluid.

11. The system of claim 10, wherein, The first fluid (F1) is water, and wherein each of the other fluids is added in a proportion equal to a proportion of the each fluid in the medical fluid.

12. The system of any one of claims 6-11, wherein, The control device (40) is configured to determine the conversion function by fitting a predetermined function to the first and second measurements of the set of test fluids.

13. The system of any preceding claim, wherein, The first sensor (20, 20a) is located upstream of the valve group (15) in the first flow path (12) such that the first sensor (20, 20a) and the second sensor (20') are fluidly connected in series when the valve group (15) is operated to open the passage from the first flow path (12) to the second flow path (16).

14. The system of any preceding claim, wherein, The control device (40) is configured, in the production phase, to intermittently operate the valve group (15) to open the passage to the second flow path (16) and direct the medical fluid to the second sensor (20'); obtain a current first measurement of the medical fluid from the first signal (S1, S1a); obtain a current second measurement of the medical fluid from the second signal (S1'); evaluate the current first and second measurements to detect a deviation; and take targeted measures when the deviation is detected.

15. The system of claim 14, wherein, The control device (40) is configured to: perform the conversion function on the current first measurement to generate a current converted measurement; and evaluate the current second measurement and the current converted measurement to detect the bias.

16. The system of claim 14 or 15, wherein, The targeted action comprises at least one of generating an alarm or performing the calibration phase (CP) to determine an updated conversion function.

17. The system of any preceding claim, wherein, The control device (40) is configured, in the production phase (PP), to monitor the speed of the pumps of the pump group (4) to detect a variation indicative of an operating error.

18. The system of any preceding claim, the at least two fluids comprising a liquid concentrate.

19. The system of claim 18, the system being configured to generate the liquid concentrate from a dry concentrate.

20. The system of any preceding claim, wherein, The control device (40) is configured, in the production phase (PP), to control the pump group (4) to generate the medical fluid at a target flow rate while maintaining the conversion measurement at a target value of the composition-related parameter.

21. The system of any preceding claim, wherein, The control device (40) is operable to initiate a procedure for ensuring reuse of the second sensor (20’).

22. The system of claim 21, wherein, The procedure for ensuring reuse comprises at least one of: a) operating a fluid supply device (10; lb; 1000) comprising the second sensor (20’) to perform an operation of flushing and / or disinfecting the second sensor (20’); or b) delivering a dedicated fluid through the second flow path (16) into the second sensor (20’), and causing a user to disconnect the second flow path (16) from the second sensor (20’), and to manipulate the second sensor (20’) to retain the dedicated fluid within the second sensor (20’).

23. The system of claim 22, wherein, The dedicated fluid is bacteriostatic.

24. The system of claim 22 or 23, the system being configured to provide the dedicated fluid based on at least one of the at least two fluids.

25. The system of any preceding claim, wherein, The at least two fluids comprise a first fluid (Fl) provided by a first source (3a) and a second fluid (F2) provided by a second source (3b), wherein the pump group (4) comprises a first pump (Pl) configured to deliver the first fluid (Fl) from the first source (3a) into the first flow path (12), and a second pump (P2) configured to deliver the second fluid (F2) from the second source (3b) into the first flow path (12) to generate a mixture of the first fluid (Fl) and the second fluid (F2) in the first flow path (12).

26. The system of claim 25, wherein, The control device (40) is configured, in the production phase (PP), to operate the first pump (Pl) and the second pump (P2) to pump the first fluid (Fl) and the second fluid (F2) through the first flow path (12) to provide the mixture in the first flow path (12), wherein the second pump (P2) is controlled based on the conversion measurement.

27. The system of claim 25 or 26, wherein, A connection line (13) extends from the second source (3b) to a junction (13b) on the first flow path (12), wherein the second pump (P2) is arranged in or on the connection line (13) to deliver the second fluid (F2) from the second source (3b) into the first flow path (12), and wherein the first pump (P1) is arranged in or on the first flow path (12) between the junction (13b) and an outlet (12a) for the medical fluid.

28. The system of claim 27, wherein, The control device (40) is configured to control the first pump (P1) to generate the target flow of the medical fluid in the production phase (PP).

29. The system according to any one of claims 25-28, further comprising a first scale (2a) and a second scale (2b), wherein, The first source is a first container (3a) arranged on the first scale (2a), wherein the second source is a second container (3b) arranged on the second scale (2b), wherein the control device (40) is configured to control, in the calibration phase (CP) and / or in the production phase (PP), the pump group (4) based on weight variations of the first container (3a) and of the second container (3b) given by a first output signal (S2) of the first scale (2a) and by a second output signal (S3) of the second scale (2b).

30. The system of claim 29, wherein, The control device (40) is configured to monitor the first output signal (S2) and the second output signal (S3) to detect variations indicative of an operating error in the production phase (PP).

31. The system of any preceding claim, wherein, The outlet (12a) is connected to a receiving device (30), wherein the control device (40) is configured to detect, in the production phase (PP), an interruption in the operation of the receiving device (30) while the medical fluid is being directed along the first flow path (12) to the outlet (12a), and to operate the valve group (15) to close the first flow path (12) and open a passage to the second flow path (16), and to reduce the pumping speed of the at least one pump of the pump group (4) upon detection of the interruption in the operation.

32. The system of claim 31, wherein, The control device (40) is further configured to operate the pump group (4) to generate the medical fluid upon detection of the interruption in the operation.

33. The system of any preceding claim, wherein, The composition-related parameter represents an electrical conductivity, an electrical resistivity, a concentration of one or more solutes, or a pH.

34. The system of any preceding claim, wherein, The medical fluid is a treatment fluid used in extracorporeal blood treatment or peritoneal dialysis treatment.

35. A control method for operating a system according to any preceding claim, the method comprising: The valve group and the pump group are operated (201) in the calibration phase to deliver at least one of the at least two fluids to the first sensor and to the second sensor; The control device (40) is configured to control the first pump (P1) to generate the target flow of the medical fluid in the production phase (PP). determining (202) a conversion function during the calibration phase based on the first signal and the second signal, the conversion function for converting a measurement in the first signal to a measurement in the second signal; and operating (203) the valve set and the pump set to pump the at least two fluids through the first flow path to provide the medical fluid at the outlet during the production phase; wherein the operating (203) in the production phase comprises controlling (203c) at least one pump in the pump set based on a converted measurement, the converted measurement given by performing the conversion function on a measurement in the first signal from the first sensor during the production phase.

36. A computer readable medium comprising computer instructions which, when executed by a processor (41), cause the processor (41) to perform the method according to claim 35.

37. A disposable set for use in the system of any one of claims 1-34, the disposable set comprising: the first flow path (12), the first sensor (20), and the second flow path (16), the second flow path (16) extending from the first flow path (12) to a detachable fluid connector (16a) for connecting in fluid communication with the second sensor (20').

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