Patent Publication Number: US-2020282125-A1

Title: Individualized dialysis with inline sensor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit of U.S. Provisional Patent Application No. 62/967,349, filed Jan. 29, 2020, and U.S. Provisional Patent Application No. 62/815,242, filed Mar. 7, 2019, both of which are incorporated by reference herein in their entirety. 
    
    
     BACKGROUND 
     Patients with kidney failure or partial kidney failure typically undergo hemodialysis treatment at hemodialysis treatment centers, clinics, or in the home. When healthy, kidneys maintain the body&#39;s internal equilibrium of water and minerals (e.g., sodium, potassium, chloride, calcium, phosphorous, magnesium, and sulfate). In hemodialysis, blood is taken from a patient through an intake needle (or catheter) which draws blood from an artery located in a specific access location (arm, thigh, subclavian, etc.). The blood is then pumped through extracorporeal tubing via a peristaltic or other pump, and then through a special filter called a dialyzer. The blood passes through the dialyzer in contact with an internal semipermeable membrane, typically in a countercurrent direction to the flow of a dialysate solution on the opposite side of the membrane. The dialyzer is intended to remove unwanted toxins such as urea, nitrogen, and potassium, as well as excess water from the blood by diffusion and/or convective transport, depending on the specific type of dialysis ordered. The dialyzed blood then flows out of the dialyzer via additional tubing and through a needle (or catheter) back into the patient. 
     During dialysis, an excess of electrolytes in the patient&#39;s blood may be lost. Also in some cases, dialysis may result in insufficient removal of electrolytes. For example, blood contains sodium ions (Na + ), potassium ions (K + ), and calcium ions (Ca 2+ ). Too much sodium in the blood can contribute to the patient feeling an increase in thirst or can lead to hypertension. Losing too much sodium can lead to decline in blood volume, chest pain, nausea, vomiting, headache, and muscle cramps. Too much potassium in the blood can lead to muscle pain, weakness, and numbness. Losing too much potassium can lead to heart rhythm disturbances. Having too much calcium in the blood can lead to vascular calcification. Losing too much calcium can lead to bone disorders and/or uncontrollable secondary parathyroid hormone (PTH) secretion. 
     Electrolyte composition in the blood is a highly dynamic function, dependent on many physiological and nutritional inputs, and subject to significant variability between patients. In most dialysis settings, one or only a small number of dialysate compositions (i.e., “recipes”) is available to treat patients, regardless of individual variations in electrolyte profiles that exist between patients or even between the same patient on different days. This “one-size-fits-all” approach to treatment may be reasonable for the majority of patients, but some patients do not tolerate it well. Accordingly, a method and system for preparing a patient-specific dialysate would be advantageous, and one that can adapt to real-time changes in patient needs between and even during dialysis treatments. 
     SUMMARY 
     An embodiment of the disclosure provides a method for adjustment of a dialysate during dialysis for a patient. The method comprises: subsequent to initiating dialysis for the patient, obtaining, by a controller and from an electrolyte sensor, a measurement of a concentration of an electrolyte in the patient&#39;s blood; determining, by the controller, whether the obtained measurement is within a predefined range; in response to determining that the measurement is not within the predefined range, determining, by the controller and based on the obtained measurement, at least one first adjustment value for adjusting a composition of the dialysate, wherein the composition of the dialysate is based on respective amounts of chemicals dispensed from a plurality of chemical sources; and controlling, by the controller and based on the at least one first adjustment value, a dispenser to adjust the composition of the dialysate during dialysis for the patient by changing one or more of the respective amounts of chemicals dispensed from the plurality of chemical sources. 
     In another embodiment of the disclosure, the method comprises controlling, based on the at least one first adjustment value, the dispenser to adjust the composition of the dialysate by providing one or more first instructions to direct the dispenser to adjust the composition of the dialysate. Additionally, the method further comprises: subsequent to adjusting the composition of the dialysate during dialysis based on the at least one first adjustment value, obtaining, by the controller, a second measurement of the concentration of the electrolyte in the patient&#39;s blood from the one or more electrolyte sensors; determining, by the controller, whether the at least one first adjustment value caused the second measurement to be within the predefined range; and in response to determining that the second measurement is not within the predefined range, providing one or more second instructions to the dispenser to adjust the composition of the dialysate during dialysis based on the second measurement. 
     In another embodiment of the disclosure, the method further comprises in response to determining that the second measurement is within the predefined range, maintaining the composition of the dialysate during dialysis. 
     In another embodiment of the disclosure, the method further comprises: obtaining, by the controller, a second measurement of a second concentration of a second electrolyte in the patient&#39;s blood, wherein the second electrolyte and the first electrolyte are different electrolytes; determining, by the controller, whether the second measurement is within a second predefined range; in response to determining that the second measurement is not within the second predefined range, determining, by the controller and based on the second measurement, at least one second adjustment value for adjusting the composition of the dialysate, and wherein controlling the dispenser to adjust the composition of the dialysate is based on the at least one first adjustment value and the at least one second adjustment value. 
     In another embodiment of the disclosure, the method comprises controlling the dispenser to adjust the composition of the dialysate by generating, by the controller, actuating signals for changing the composition of the dialysate during dialysis based on the at least one first adjustment value; and providing, by the controller, the actuating signals to one or more actuators of the dispenser to change proportions of the respective amounts of chemicals dispensed from the plurality of chemical sources. 
     In another embodiment of the disclosure, the method comprises: based on determining the at least one first adjustment value the electrolyte is an increase, generating a first actuating signal for dispensing a higher proportion of a respective chemical of a respective chemical source of the plurality of chemical sources; and based on determining the at least one first adjustment value the electrolyte is a decrease, generating a second actuating signal for dispensing a lower proportion of the respective chemical of the respective chemical source of the plurality of chemical sources. 
     In another embodiment of the disclosure, the method further indicates each actuating signal of the actuating signals is encoded as: a reduction in the number of electrical pulses provided to one actuator of the one or more actuators, an increase in the number of electrical pulses provided to one actuator of the one or more actuators, a reduction in the number of electrical pulses provided to all but one actuator of the one or more actuators, or an increase in the number of electrical pulses provided to all but one actuator of the one or more actuators. 
     In another embodiment of the disclosure, the method further comprises: receiving, by the controller, a fresh dialysate signal at time t f , the fresh dialysate signal indicating that the dialysate is mixed and ready for use; and determining, by the controller and based on a flowrate of the dialysate and a volume of the dialysate, a time t max  indicating a maximum amount of time after t f  to adjust the composition of the dialysate. 
     In another embodiment of the disclosure, the electrolyte sensor is an optical sensor. 
     In another embodiment of the disclosure, the electrolyte sensor is the NMR sensor, and wherein the NMR sensor is configured to obtain a real-time sodium concentration, a real-time potassium concentration, or a real-time phosphorous concentration. 
     In another embodiment of the disclosure, the electrolyte sensor is located upstream of a dialyzer and configured to interface with a tubing upstream of the dialyzer. 
     In another embodiment of the disclosure, the electrolyte sensor is located downstream of a dialyzer and configured to interface with a tubing downstream of the dialyzer. 
     In another embodiment of the disclosure, the method comprises determining a dialysate recipe based on the patient, and wherein determining the at least one first adjustment value for adjusting the composition of the dialysate is based on the dialysate recipe. 
     In another embodiment of the disclosure, the method comprises determining the dialysate recipe based on historical trend analysis from the patient&#39;s previous dialysis treatments. 
     In another embodiment of the disclosure, the method comprises controlling the dispenser to adjust the composition of the dialysate comprises providing one or more first instructions to the dispenser to adjust the composition of the dialysate. The method further comprises: subsequent to providing the one or more first instructions, obtaining, by the controller, a second measurement of the concentration of the electrolyte from the one or more electrolyte sensors; and determining an effectiveness of the dialysate recipe based on the second measurement. 
     In another embodiment of the disclosure, the method comprises determining the effectiveness of the dialysate recipe based on whether the second measurement is within the predefined range. The method further comprises based on determining the second measurement is not within the predefined range, selecting a new dialysate recipe; determining at least one second adjustment value for adjusting the composition of the dialysate based on the new dialysate recipe; and providing, to the dispenser of the electrolyte composition monitor, one or more second instructions to adjust the composition of the dialysate during dialysis based on the at least one second adjustment value. 
     In another embodiment of the disclosure, the method further comprises based on determining the dialysis for the dialysis patient has concluded, storing the dialysate recipe and the determined effectiveness of the dialysate recipe in memory. 
     Another embodiment of the disclosure provides a non-transitory computer-readable medium having processor-executable instructions stored thereon for adjustment of a dialysate during dialysis for a patient. The processor-executable instructions, when executed, facilitate: subsequent to initiating dialysis for the patient, obtaining, from an electrolyte sensor, a measurement of a concentration of an electrolyte in the patient&#39;s blood; determining whether the obtained measurement is within a predefined range; in response to determining that the measurement is not within the predefined range, determining, based on the obtained measurement, at least one first adjustment value for adjusting a composition of the dialysate, wherein the composition of the dialysate is based on respective amounts of chemicals dispensed from a plurality of chemical sources; and controlling, based on the at least one first adjustment value, a dispenser to adjust the composition of the dialysate during dialysis for the patient by changing one or more of the respective amounts of chemicals dispensed from the plurality of chemical sources. 
     Another embodiment of the disclosure provides a system for adjustment of a dialysate during dialysis for a patient. The system comprises an electrolyte sensor configured to measurement a measurement of a concentration of an electrolyte in the patient&#39;s blood; and an electrolyte composition monitor. The electrolyte composition monitor comprises a controller and a dispenser. The controller is configured to: subsequent to initiating dialysis for the patient, obtain, from the electrolyte sensor, the measurement of the concentration of the electrolyte in the patient&#39;s blood; determine whether the obtained measurement is within a predefined range; in response to determining that the measurement is not within the predefined range, determine, based on the obtained measurement, at least one first adjustment value for adjusting a composition of the dialysate, wherein the composition of the dialysate is based on respective amounts of chemicals dispensed from a plurality of chemical sources; and provide, based on the at least one first adjustment value, one or more first instructions to a dispenser to adjust the composition of the dialysate during dialysis for the patient by changing one or more of the respective amounts of chemicals dispensed from the plurality of chemical sources. The dispenser is configured to: adjust the composition of the dialysate during dialysis based on the one or more first instructions. 
     In another embodiment of the disclosure, the controller is further configured to: subsequent to adjusting the composition of the dialysate during dialysis based on the at least one first adjustment value, obtain a second measurement of the concentration of the electrolyte in the patient&#39;s blood from the one or more electrolyte sensors; determine whether the at least one first adjustment value caused the second measurement to be within the predefined range; and in response to determining that the second measurement is not within the predefined range, provide one or more second instructions to the dispenser to adjust the composition of the dialysate during dialysis based on the second measurement. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a front perspective view of a hemodialysis system that includes an electrolyte composition monitor according to some embodiments of the disclosure; 
         FIG. 2  is a block diagram illustrating use of an electrolyte composition monitor with a patient, according to embodiments of the disclosure; 
         FIG. 3  is a flow diagram for managing electrolytes in blood of a dialysis patient during dialysis, according to an embodiment of the disclosure; 
         FIG. 4  is an example timeline for managing electrolytes in blood of a dialysis patient during dialysis, according to an embodiment of the disclosure; 
         FIG. 5  is a flow diagram for determining individualized dialysate recipes or prescriptions for a patient; 
         FIG. 6  is a block diagram of an example computer system; and 
         FIGS. 7 a  and 7 b    are graphical representations of real-time electrolyte concentration measurements using an NMR sensor. 
     
    
    
     DETAILED DESCRIPTION 
     During dialysis, an electrolyte composition monitor according to embodiments of the disclosure can employ a dialysate mixing system to make an amount of dialysate on demand using, among other things, a plurality of chemical concentrates. The dialysate generated will have a formula, recipe, or prescription that differs from dialysate previously used during dialysis. The dialysate&#39;s formula will thus be adjusted during dialysis based on the electrolyte composition monitor detecting an elevated or depressed level of one or more electrolytes in a patient&#39;s blood during dialysis. 
     In an embodiment, the dialysate used during dialysis is made in batches. Each batch follows a prescription, formula, or recipe chosen by the electrolyte composition monitor based on receiving electrolyte concentration levels from the patient&#39;s blood. The electrolyte composition monitor may continually adjust a next dialysate batch&#39;s recipe and task its dialysate mixing system to follow the prescribed recipe. For example, the dialysate mixing system may receive a recipe indicating particular chemical constituents and amounts of each chemical constituent to be included in the dialysate. Based on the prescription, the dialysate mixing system can determine, for example, a number of tablets, mass of powder, or volume of concentrated electrolyte solution required for each chemical constituent. Tablets, powders and/or concentrated electrolyte solutions, can be automatically dispensed and mixed with purified water, bicarbonate, and/or sodium chloride in a mixing chamber to produce the dialysate according to the desired dialysate recipe. 
     Embodiments of the disclosure allow for chemical constituents to be delivered and stored in a tablet form or in a concentrated form, thus requiring minimal storage space and oversight. Mixing the dialysate in batches throughout dialysis suggests less storage space is required since the volume of dialysate made can be fully exhausted during a treatment session. 
     Embodiments of the disclosure allow for the dialysate composition used during dialysis to be personalized, whereby a patient&#39;s individual responses to dialysis are taken into account by monitoring his electrolyte responses to the dialysis treatment throughout the treatment session. In this way, a one-size-fits-all rule or a coarse heuristic is not applied during the treatment. The electrolyte composition monitor, through its continuous adjustments of dialysate composition, can effectively personalize treatment to the individual patient, ensuring that the patient does not leave the dialysis treatment with deficient levels or elevated levels of certain monitored electrolytes, and improving long-term outcomes and patient satisfaction. 
     Embodiments of the disclosure allow for an electrolyte composition monitor that can, over time, learn a dialysis recipe or formula most appropriate for the patient. By continually adjusting the dialysate in batches, the electrolyte composition monitor can determine which electrolytes the patient is typically sensitive to; thus, in further treatments, the electrolyte composition monitor can suggest a starting dialysate recipe that is more appropriate for the patient. In this way, embodiments of the electrolyte composition monitor will allow for a learning model tailored to adapt to evolving patient needs. 
     Embodiments of the disclosure provide individualized dialysis treatment based on online monitoring of electrolytes in the patient&#39;s blood by generating individualized dialysate as electrolyte conditions in the patient&#39;s blood change during treatment. This improvement solves a problem in current treatment practice where dialysate formulas and recipes for individual patients are based on monthly lab blood test results. Dialysis patients are rarely in steady state, so a lab blood test may be outdated by the time the patient enters the clinic for dialysis. Thus, reliance on monthly lab testing may prove harmful or of limited benefit to individual patients. 
       FIG. 1  shows a dialysis system, in particular, a hemodialysis system  100 . Although the system described herein is largely described in connection with hemodialysis systems by way of example, it is explicitly noted that the system described herein may be used in connection with other types of medical devices and treatments, including peritoneal dialysis systems. The hemodialysis system  100  includes a hemodialysis machine  102  connected to a disposable blood component set  104  that partially forms a blood circuit. During hemodialysis treatment, an operator connects an arterial patient line  106  and a venous patient line  108  of the blood component set  104  to a patient. The blood component set  104  includes an air release device  112 . As a result, if blood passing through the blood circuit during treatment contains air, the air release device  112  will vent the air to atmosphere. 
     The blood component set  104  is secured to a module  130  attached to the front of the hemodialysis machine  102 . The module  130  includes a blood pump  132  capable of circulating blood through the blood circuit. The module  130  also includes various other instruments and sensors, e.g., electrolyte sensors, capable of monitoring the blood flowing through the blood circuit. The module  130  includes a door that when closed, as shown in  FIG. 1 , cooperates with the front face of the module  130  to form a compartment that is sized and shaped to receive the blood component set  104 . 
     The blood pump  132  is part of a blood pump module  134 . The blood pump module  134  includes a display window, a start/stop key, an up key, a down key, a level adjust key, and an arterial pressure port. The display window displays the blood flow rate setting during blood pump operation. The start/stop key starts and stops the blood pump  132 . The up and down keys increase and decrease the speed of the blood pump  132 . The level adjust key raises a level of fluid in an arterial drip chamber. 
     The hemodialysis machine  102  further includes a dialysate circuit formed by the dialyzer  110 , various other dialysate components, and dialysate lines connected to the hemodialysis machine  102 . Many of these dialysate components and dialysate lines are inside the housing  103  of the hemodialysis machine  102  and are thus not visible in  FIG. 1 . During treatment, while the blood pump  132  circulates blood through the blood circuit, dialysate pumps (not shown) circulate dialysate through the dialysate circuit. 
     The dialysate is created by the hemodialysis machine  102  in batches. That is, the hemodialysis machine  102  is configured to mix various chemical constituents of the dialysate together to form a dialysate batch having requisite characteristics based on measurements of electrolyte concentration in the patient&#39;s blood. In this way, dialysate used during the dialysis treatment can be optimized for the specific patient for different phases of the treatment based on how the patient is responding to the treatment. 
     The hemodialysis machine  102  includes an electrolyte composition monitor ( 200  of  FIG. 2 ), which is made up of a controller  101  and a dialysate mixing system  105  for mixing dialysate. During dialysis, the controller  101  is configured to receive electrolyte measurements from the patient&#39;s blood, and the controller  101  is configured to provide signals for adjusting the dialysate recipe for dialysate batches throughout the dialysis treatment. The dialysate mixing system  105  is internal to the housing  103  of the hemodialysis machine  102 . In an embodiment, water, sodium chloride (NaCl), bicarbonate (NaHCO3), and a plurality of chemical concentrates are mixed together to form the dialysate. The dialysate mixing system  105  provides already mixed dialysate to the dialyzer  110  via at least a dialysate supply line, which is also internal to the housing  103  of the hemodialysis machine  102 . A drain line  128  and an ultrafiltration line  129  extend from the hemodialysis machine  102 . The drain line  128  and the ultrafiltration line  129  are fluidly connected to the various dialysate components and dialysate lines inside the housing  103  of the hemodialysis machine  102  that form part of the dialysate circuit. During hemodialysis, the dialysate supply line carries fresh dialysate through various dialysate components, including the dialyzer  110 . As the dialysate passes through the dialyzer  110 , it collects toxins from the patient&#39;s blood. The resulting spent dialysate is carried from the dialysate circuit to a drain via the drain line  128 . When ultrafiltration is performed during treatment, a combination of spent dialysate and excess fluid drawn from the patient is carried to the drain via the ultrafiltration line  129 . 
     In an embodiment, the controller  101  determines the chemical composition of each batch of dialysate. For example, a batch of dialysate may be  12  liters (L) and the chemical composition may include a plurality of chemical concentrates. The chemical concentrates may be liquid concentrates of varying viscosity and/or may be solid concentrates in the form of tablets, pills, or powders. The controller  101  may compute the chemical composition (e.g., an amount of each of the plurality of chemical concentrates such as a number of tablets) for each 12 L batch of dialysate based on a prescription issued by a physician/doctor. 
     In an embodiment, the controller  101  may use a reduced volume of the dialysate for the dialysis treatment of the patient. For example, the controller  101  may reduce the dialysate to blood flow ratio for the dialysis treatment. By reducing the dialysate to blood flow ratio, the dialysis treatment may consume less dialysate (e.g., 40 L of the dialysate per dialysis treatment may be used instead of 120 L). 
     A drug pump  192  also extends from the front of the hemodialysis machine  102 . The drug pump  192  is a syringe pump that includes a clamping mechanism configured to retain a syringe  178  of the blood component set  104 . The drug pump  192  includes a stepper motor configured to move the plunger of the syringe  178  along the axis of the syringe  178 . The drug pump  192  can thus be used to inject a liquid drug (e.g., heparin) from the syringe  178  into the blood circuit via a drug delivery line  174  during use, or to draw liquid from the blood circuit into the syringe  178  via the drug delivery line  174  during use. 
     The hemodialysis machine  102  includes a user interface with input devices such as a touch screen  118  and a control panel  120 . The touch screen  118  and the control panel  120  allow an operator to input various different treatment parameters to the hemodialysis machine  102  and to otherwise control the hemodialysis machine  102 . The touch screen  118  allows an operator to select between user profiles, and the control panel  120  can allow the operator to select between user profiles by scanning the patient&#39;s membership card. The touch screen  118  displays information to the operator of the hemodialysis system  100 . The controller  101  is also configured to receive and transmit signals to the touch screen  118  and the control panel  120 . The controller  101  can control operating parameters of the hemodialysis machine  102 , e.g., providing signals at appropriate times for adjusting composition of dialysate throughout a dialysis treatment. The dialysate mixing system can be, e.g., the dialysate mixing system in Kalaskar et al., US 2018/0326138, which is hereby incorporated herein in its entirety. 
       FIG. 2  is a block diagram illustrating use of an electrolyte composition monitor  200  with a patient  210  during dialysis, according to embodiments of the disclosure. Components of the hemodialysis system  100  of  FIG. 1  are used as an example, but as previously stated, the electrolyte composition monitor  200  can be used in peritoneal dialysis. The electrolyte composition monitor  200  is configured to receive electrolyte measurements from one or more electrolyte sensors  212 . The electrolyte composition monitor  200  is also configured to use the electrolyte measurements to adjust dialysate recipe, mix a new batch of dialysate, and provide fresh dialysate to the dialyzer  110 . 
     The electrolyte composition monitor  200  includes the controller  101  and the dialysate mixing system  105 . The controller  101  is configured to interface with the electrolyte sensors  212  to receive the electrolyte measurements. Examples of the controller  101  include a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), and a processor with non-transitory computer-readable medium. 
     The dialysate mixing system  105  includes a dispenser  202  and a mixing chamber  204 . The dispenser  202  can include chemical concentrates in chemical sources  206 . The chemical concentrates are used as ingredients of the dialysate mixture. The chemical concentrates can be liquid concentrates of varying viscosity or can be solid concentrates in the form of tablets, pills, or powders. The chemical sources  206  are containers that hold these chemical concentrates. Chemical sources  206  can thus hold concentrates of potassium chloride (KCl), calcium chloride (CaCl 2 ), magnesium chloride (MgCl 2 ), citric acid, dextrose, sodium chloride (NaCl), sodium bicarbonate (NaHCO 3 ), acetic acid, glucose, and so on. Not all chemical concentrates available need to be used in a dialysate formula or recipe. For example, one recipe may only call for acetic acid, NaCl, CaCl 2 , KCl, MgCl 2 , and glucose. Another recipe may call for bicarbonate, NaCl, CaCl 2 , KCl, and MgCl 2 , without glucose. 
     The dispenser  202  can further include actuators  208  that aid in dispensing specific amounts of the chemical concentrates to a mixing chamber  204  for mixing a batch of dialysate. The actuators  208  not only control the amount of chemical concentrates provided to the mixing chamber  204 , but also control an amount of water used in mixing the batch of dialysate. A water source  205  can be a water connection for receiving filtered water or water suitable for use in dialysis treatment. The water source  205  can connect to the hemodialysis system  100  via an inlet tube. 
     The dispenser  202  provides the chemical concentrates and water to the mixing chamber  204 . Contents in the mixing chamber  204  are agitated for an appropriate amount of time until chemical concentrates are sufficiently distributed throughout. In some embodiments, the mixing chamber  204  increases its temperature to assist in dissolving and/or distributing the chemical concentrates to yield a homogenous solution. After realizing a homogenous solution, the mixing chamber  204  can be brought to an appropriate temperature for dialysis treatment. 
     The mixing chamber  204  of the dialysate mixing system  105  provides the mixed dialysate to the dialyzer  110 . In an embodiment, the mixing chamber  204  is multi-chambered where a first chamber is used for mixing dialysate and a second chamber is used for storing and delivering dialysate to the dialyzer  110 . In an embodiment, the mixing chamber  204  includes sensors for sensing levels of dialysate in both the first and second chambers. The mixing chamber  204  may also alert the controller  101  when a batch of dialysate has been mixed and when fresh dialyzer from the batch of dialysate is provided to the dialyzer  110 . 
     The dialyzer  110  receives blood from the patient  210  via the arterial patient line  106 . Electrolyte sensors along the arterial patient line  106  may be provided for measuring electrolyte concentration in blood upstream of the dialyzer  110 . These electrolyte sensors are identified as arterial electrolyte sensors  212 - 1  in  FIG. 2 . The dialyzer  110  returns blood to the patient  210  via the venous patient line  108 . Electrolyte sensors along the venous patient line  108  may be provided for measuring electrolyte concentration in blood downstream of the dialyzer  110 . These electrolyte sensors can be identified as venous electrolyte sensors  212 - 2 . Furthermore, electrolyte sensors not interrupting the dialysis circuit can be interfaced with the patient  210 . For example, a sensor can be placed along a peripherally inserted central catheter (PICC) line to measure electrolyte concentration. These sensors are identified as non-dialysis circuit electrolyte sensors  212 - 3 . 
     The electrolyte sensors  212  are configured to measure electrolyte concentration in the blood of the patient  210 . The electrolyte sensors  212  can be, for example, conductivity sensors, nuclear magnetic resonance (NMR) sensors and/or optical sensors. NMR sensors may detect, determine, and/or obtain real-time electrolyte concentrations (e.g., sodium concentrations) in the blood of the patient  210 . Additionally, and/or alternatively, NMR sensors may be modified (e.g., re-tuned to different radio frequencies) to detect, determine, and/or obtain real-time potassium and/or phosphorous concentrations. Additionally, and/or alternatively, in some embodiments, an NMR sensor measures concentrations of free sodium in both the dialysate and the blood, each sampled separately, and the concentration of free sodium is reported to the controller  101 . Furthermore, the sodium and other electrolyte concentrations may vary from patient to patient and even for a given patient between consecutive dialysis sessions. Accordingly, using an NMR sensor or other sensor to measure these concentrations in real-time to adjust the electrolyte concentrations and even using individualized recipes (described in  FIGS. 3 and 5 ) may be beneficial to provide the optimal treatment for the patient during dialysis. Additionally, and/or alternatively, the electrolyte sensors  212  may include optical sensors configured to detect real-time electrolyte concentrations such as calcium concentrations and/or magnesium concentrations. 
     Examples of an NMR sensor usable with exemplary embodiments of the present application are described in further detail in U.S. Pat. No. 10,371,775 (Titled: Dialysis System With Radio Frequency Device Within A Magnet Assembly For Medical Fluid Sensing And Concentration Determination), granted on Aug. 6, 2019, and U.S. Provisional Patent Application No. 62/967,349 (Titled: Individualized And On-Demand Dialysis System With Networking Capabilities), filed on Jan. 29, 2019, both of which are incorporated by reference herein in its entirety. 
     Furthermore,  FIG. 7  shows graphical representations of real-time measurements obtained using an NMR sensor. For example,  FIG. 7 a    shows real-time electrolyte concentration (e.g., sodium concentration) measurements using the NMR sensor. Line  702  indicates the sodium concentration and the shaded area  704  represents the accuracy margin.  FIG. 7 b    also shows real-time electrolyte concentration measurements using the NMR sensor. For example, portion  704  of line  702  indicates the baseline sodium concentration. Then, portion  708  indicates a first adjustment of the baseline sodium concentration (e.g., introducing or injecting sodium boluses to increase the sodium concentration). Portion  710  shows another injection of sodium boluses for increasing the sodium concentration again. 
       FIG. 3  is a flow diagram for managing electrolytes in blood of a dialysis patient during dialysis, according to an embodiment of the disclosure.  FIG. 3  is a flow diagram illustrating a process  300  that an electrolyte composition monitor, e.g., electrolyte composition monitor  200 , can perform in managing electrolytes in blood of patient  210 . At  302 , the controller  101  of the electrolyte composition monitor  200  receives (e.g., obtains) electrolyte measurements from electrolyte sensors  212 . The obtained electrolyte measurements may include sodium, potassium, phosphorous, magnesium, and/or calcium electrolyte concentrations in the blood of the patient  210 . 
     At  304 , the controller  101  determines from the electrolyte measurements whether electrolyte concentrations in the blood are within predefined ranges. In an example, electrolyte concentration of sodium in the blood should be within 135-145 mEq/L range, electrolyte concentration of potassium should be within 3.5-5 mEq/L range, electrolyte concentration of calcium should be within 8.5-10.2 mg/dL (2-2.6 mmol/L) range, and so on. The electrolyte measurements received at the controller  101  are prepared in a manner to obtain electrolyte concentrations. For example, if a sodium NMR sensor provides radio frequency (RF) energy level at a resonant frequency of sodium as measurement signals, then the controller  101  analyzes the RF energy level provided to determine the concentration of sodium in the blood. This concentration of sodium is compared to the upper and lower bounds of the predefined range for sodium to determine whether sodium concentration in the blood is within the predefined range. 
     In some examples, the predefined ranges are clinically defined ranges such as clinically known ranges. In other examples, the predefined ranges may be individualized. For example, as described below in  502  of  FIG. 5 , the dialysate recipe is a recipe determined based on historical trend analysis on electrolyte measurements from the patient&#39;s previous dialysis treatments. In other words, the dialysate recipe is individualized for the patient  210  based on the previous dialysis treatments performed on the patient  210 . The dialysate recipe associated with the patient may include electrolyte ranges (e.g., an electrolyte concentration range for sodium, potassium, calcium, magnesium, and/or phosphorous). Further, as described below in  FIG. 5 , the controller  101  may load the dialysate recipe prior to beginning the dialysis treatment. At  302 , the controller  101  determines the predefined ranges based on the loaded dialysate recipe and may compare these predefined ranges with the electrolyte concentrations from the electrolyte measurements. 
     At  306 , the controller  101  determines adjustment values, based on the plurality of electrolyte measurements, for one or more electrolyte concentrations outside the predefined ranges. The controller  101  determines, for each electrolyte concentration outside of the predefined ranges, whether to increase or decrease concentration of the electrolyte. Increasing or decreasing the concentration provides directionality to the adjustment values. The controller  101  then determines the magnitude of the adjustment value by determining a target amount by which the concentration of the electrolyte should be increased. 
     In an embodiment, the controller  101  determines adjustment values by unit increments. That is, after determining whether to increase or decrease a concentration of an electrolyte that is not within a predefined range, the controller  101  determines that the concentration of the electrolyte should be adjusted by a given unit. In an embodiment where chemical constituents of dialysate are adjusted by tablets, each unit represents an electrolyte concentration provided by a chemical concentrate&#39;s respective tablet. In an embodiment where chemical constituents of dialysate are adjusted by liquid concentrates, each unit represents an expected electrolyte concentration provided by opening its respective valve for a predetermined amount of time. Although one unit increments are described, adjustment values can be determined as multiple unit increments. For example, the controller  101  can determine that the concentration of the electrolyte that is not within its predefined range should be increased by three units which correspond to an amount of electrolytes expected from three tablets. 
     In an embodiment, the controller  101  determines adjustment values based on pre-programmed dialysate recipes, formulas or prescriptions. The controller  101  can store one or more recipes for various electrolyte conditions in its memory. For example, the memory may include a recipe for low sodium, high sodium, low potassium, high potassium, and so on. Each of these dialysate recipes can be tagged as being effective in reducing or raising one or more electrolyte concentrations. That way, based on a combination of electrolytes determined to be outside their respective predefined ranges, the controller  101  can select a recipe from one of these predefined recipes for the next batch of dialysate. 
     In some examples and referring to  FIG. 5  and process  500  below, the controller  101  determines the magnitude and/or directionality of the adjustment values (e.g., unit increments) based on the loaded dialysate recipe from  502 . For example, the controller  101  may determine and load the dialysate recipe based on historical trend analysis on electrolyte measurements from the patient&#39;s previous dialysis treatments (e.g., based on the most effective recipe from the historical trend analysis, the dialysate recipe with the greatest number of batches in the patient profile, and/or the most recent dialysate recipe used during the dialysis treatment). For instance, if the high sodium recipe has the greatest number of made batches in the patient profile (e.g., the dialysate solution was created/adjusted the greatest number of times using the recipe), the controller  101  may determine the high sodium recipe as the most effective dialysate recipe and load that recipe at  502 . Then, at  306 , the controller  101  may determine the magnitude of the adjustment values using this recipe. 
     In an embodiment, the controller  101  determines that one or more electrolyte concentrations outside the predefined ranges deviates significantly from the predefined ranges. For example, at  304 , a potassium concentration of 6.0 mEq/L is determined, and the predefined range for potassium is between 3.5 and 5.0 mEq/L. The potassium concentration is then determined by the controller  101  to be too high. The controller  101  can determine that the next dialysate batch should decrease the potassium concentration. Thus, the controller  101  can determine an adjustment value for potassium that reduces the potassium ion concentration in the next batch of dialysate as prescribed. Although potassium is used as an example, the controller  101  can determine that concentration of more than one electrolyte in the blood is too high and determine adjustment values to make a next batch of dialysate. In other words, the controller  101  may determine that an electrolyte concentration (e.g., potassium) is outside of the predefined ranges and determine one or more adjustment values for the next dialysate batch. The one or more adjustment values may be a single adjustment value for the electrolyte concentration (e.g., potassium) or may include multiple adjustments values for multiple different electrolyte concentrations (e.g., potassium, calcium, and so on). 
     Additionally, and/or alternatively, the controller  101  may determine multiple electrolyte concentrations (e.g., potassium and calcium) are outside of the predefined ranges and may determine one or more adjustment values for the next dialysate batch. The one or more adjustment values may be a single adjustment value for the electrolyte concentration (e.g., potassium) or may include multiple adjustments values for multiple different electrolyte concentrations (e.g., calcium, potassium, and so on). 
     In an embodiment, the controller  101  determines that a majority or all of the electrolyte concentrations are outside the predefined ranges and adjustment values of all the electrolyte concentrations have a same direction. The controller  101  can determine adjustment values based on the amounts of chemicals supplied by the chemical sources  206  and the amount of water to include in the dialysate. In some instances, each batch of the dialysate may be  12  L. In other instances, the batches may be greater than 12 L such as 24 L. The controller  101  can determine adjustment values based on the amount of chemicals supplied by the chemical sources  206 , the amount of water to include in the dialysate, and the volume of the batch of the dialysate. For instance, if the prescription indicates that 2 potassium tablets are used for a 12 L batch, the controller  101  may determine to use 4 potassium tablets for a 24 L batch. 
     At  308 , the controller  101  provides instructions to the dispenser  202  to adjust the composition of the dialysate during dialysis based on the determined adjustment values of  306 . The composition of the dialysate includes chemicals from the chemical sources  206 . In an embodiment, the controller  101  generates adjustment signals for changing the composition of the dialysate during dialysis based on the determined adjustment values. The controller  101  then provides actuating signals to actuators  208  for changing how much of each chemical concentrate to release into the mixing chamber  204 . By effecting a change in an amount of any of the chemical concentrates released into the mixing chamber  204 , the controller  101  causes the dispenser  202  to change proportions of the chemicals in the dialysate. 
     In an embodiment, when a respective adjustment value for an electrolyte concentration outside the respective predefined range indicates an increase, the controller  101  generates a respective adjustment signal for dispensing a higher proportion of a respective chemical, thus increasing a chemical contribution of a respective chemical source in the chemical sources  206 . When the respective adjustment value for the electrolyte concentration outside the respective predefined range is a decrease, the controller  101  generates a respective adjustment signal for dispensing a lower proportion of the respective chemical of the respective chemical source in the chemical sources  206 . 
     In an embodiment, the adjustment signals the controller  101  provides to the dispenser  202  are encoded as a number of electrical pulses. Electrical pulses can be voltage or current pulses. For example, a number of pulses provided by the controller  101  to a respective actuator in the actuators  208  can encode an amount of a respective chemical in the chemical sources  206  to release into the mixing chamber  204 . In a previous dialysate batch, if  5  pulses were provided to an actuator that controls a release of CaCl 2  tablets into the mixing chamber  204 , then for a next dialysate batch, if  4  pulses are provided to the actuator then a lower number of CaCl 2  tablets will be released into the mixing chamber  204 . Thus, the adjustment signals generated by the controller  101  can be encoded as a change in a number of electrical pulses provided to one or more actuators. The change in number of electrical pulses can be an increase in the number of electrical pulses or a decrease in the number of electrical pulses. Furthermore, all but one actuator in the actuators  208  can receive a reduced number of electrical pulses. Conversely, all but one actuator in the actuators  208  can receive an increased number of electrical pulses. 
     After completing  308 , the controller  101  cycles back to  302  and receives new electrolyte measurements (e.g., second electrolyte measurements from the sensors  212 ). The process  300  is performed by the electrolyte composition monitor  200  until the dialysis treatment of patient  210  ends. 
     For example, in subsequent iterations, at  304 , the controller  101  determines from the electrolyte measurements whether the first adjustment values caused the new electrolyte measurements to be within the predefined ranges. If no electrolyte concentrations in the blood are outside the predefined ranges, then the controller  101  determines at  310  that no adjustment is necessary. The controller  101  keeps the most recent recipe for the new dialysate batch and the process  300  returns to  302 . If there are electrolyte concentrations that are still outside of the predefined ranges, the controller  101  may determine new adjustment values based on the recipe and provide additional instructions to adjust the composition of the dialysate during dialysis. Furthermore, the controller  101  may determine the effectiveness of the previous recipe used and/or determine a new recipe to use for the adjustment values. 
     For example, in some instances, the controller  101  may determine the effectiveness of the recipe using process  300 . As described above, the controller  101  may determine the directionality and/or magnitude of the adjustment values based on the loaded recipe. For example, the controller  101  may obtain a first and a second electrolyte measurement from the electrolyte sensors  212 . The first electrolyte measurement may be obtained in the first iteration of process  300  and the second electrolyte measurement may be obtained in the second iteration of process  300  (e.g., the second electrolyte measurement may be subsequent to adjusting the composition of the dialysate during dialysis). The controller  101  may compare the first electrolyte measurement, the second electrolyte measurements, and/or the predefined ranges to determine the effectiveness of the recipe. For instance, if the electrolyte concentration is within the predefined ranges after the adjustment, the controller  101  may determine the recipe used for the adjustment values at  306  is effective. If the electrolyte concentration is still not within the predefined ranges, the controller  101  may determine the recipe is not effective. 
     Additionally, and/or alternatively, the controller  101  may determine the effectiveness of the recipe based on how close the second electrolyte measurement is to the predefined range. For instance, if the second electrolyte measurement is within the predefined range, the controller  101  may determine the recipe is very effective. If the second electrolyte measurement is close to the predefined range, but is not within the predefined range it, the controller  101  may determine the recipe is effective. If the second electrolyte measurement is not close to the predefined range, the controller  101  may determine the recipe is not effective. If the second electrolyte measurement is even further away from the predefined range compared to the first electrolyte measurement, the controller  101  may determine the recipe is extremely ineffective. 
     In some variations, the controller  101  may dynamically rank recipes during the dialysis treatment (e.g., during process  300 ). For example, after creating each batch of the dialysate solution using the recipe, the controller  101  may determine the effectiveness of the recipe. Then, the controller  101  may determine whether to load a new dialysate recipe based on the updated effectiveness of the recipe. If the controller  101  loads a new dialysate recipe, the controller  101  may use the new dialysate recipe to determine the adjustment values. In other words, during the dialysis treatment, the controller  101  may use multiple different recipes to determine the adjustment values based on the determined effectiveness of the recipes during the treatment of the patient. 
     In some instances, the controller  101  may rank the recipes after the dialysis treatment for the patient has concluded (e.g., after process  300  has concluded). For example, the controller  101  may determine the effectiveness of the one or more recipes used during the dialysis treatment based on comparing the electrolyte concentration after the adjustment with the predefined ranges. Then, the controller  101  may store the associated effectiveness of the recipes in memory and/or rank the recipes based on the effectiveness. The next time the patient undergoes dialysis treatment, the controller  101  may load the highest ranking stored recipe for the predefined ranges and/or the adjustment values. 
     In some examples, process  300  may be used for peritoneal dialysis (PD solutions). For peritoneal dialysis, process may further include a sterilization step. For example, prior to  308 , the controller  101  may provide instructions to the dispenser  202  to sterilize the composition of the dialysate including the chemicals from the chemical sources  206 . Then, at  308 , the controller  101  provides instructions to the dispenser  202  to sterilize the chemicals from the chemical sources. 
       FIG. 4  illustrates an example timeline  400  for managing electrolytes in blood of a dialysis patient during dialysis. As described above with respect to  FIG. 3 , process  300  is cyclic or periodic, so with respect to the timeline  400 , one period of activities is highlighted via timestamps t f , t 1 , t 2 , t 3 , t 4 , and t 5 . The timestamps are defined as follows:
         t f —Time when the controller  101  receives a fresh dialysate signal indicating that a new batch of dialysate is mixed and ready for use   t 1 —Time when the controller  101  receives electrolyte measurements from the electrolyte sensors  212     t 2 —Time when the controller  101  sends adjustment signals to the actuators  208  of the dispenser  202     t 3 —Time when the actuators  208  allow chemicals and water to migrate from the chemical sources  206  and water source  205 , respectively, to the mixing chamber  204     t 4 —Time when the mixing chamber  204  starts mixing the new batch of dialysate   t 5 —Time when an old batch of dialysate is depleted       

       FIG. 4  organizes activities in  FIG. 3  according to the example timeline  400 . In Period  1 , at the start of dialysis, a fresh batch of dialysate is mixed and ready for use. At this point, the mixing chamber  204  provides a fresh dialysate signal to the controller  101  at timestamp t f . After a time duration  402 , the controller  101  receives, at timestamp t 1 , electrolyte measurements from the electrolyte sensors  212 . During a time duration  404 , the controller  101  determines adjustment signals to provide to the actuators  208 , and at timestamp t 2 , sends the adjustment signals to the actuators  208 . The actuators  208  respond to the adjustment signals after a time duration  406 , so at timestamp t 3 , the actuators  208  allow chemicals and water to migrate from their respective sources into the mixing chamber  204 . After a time duration  408 , the mixing chamber  204  then mixes its contents, at timestamp t 4 , to form a new batch of dialysate. 
     At timestamp t 5 , the old batch of dialysate is completely depleted from the mixing chamber  204 , so time duration  410  indicates a time between when the mixing chamber  204  begins mixing contents for the new batch of dialysate and when the old batch of dialysate is depleted. In some embodiments, an error is not generated by the controller  101  when the new batch of dialysate is ready before the old batch of dialysate is depleted. This condition is indicated in  FIG. 4  by showing that a fresh dialysate signal is provided at timestamp t f  during time duration  410 . 
     In an embodiment, the controller  101  can optimize the process  300  by trying to reduce the time duration  412  between timestamps t f  and t 5 . That way, the new batch of dialysate is ready at a same time that the old batch of dialysate is depleted so that when the fresh dialysate signal is received at the controller  101 , the controller  101  can determine an appropriate time duration  402  to wait before obtaining electrolyte measurements from the electrolyte sensors  212 . That way, the controller  101  gives enough time to be able to view the effects of the new batch of dialysate on the electrolytes in the blood. 
     Put another way, the controller  101  can monitor t prep , a time duration between when the controller  101  sends adjustment signals to the actuators  208  and when the controller  101  receives the fresh dialysate signal from the mixing chamber  204 . The controller  101  can try to optimize t prep  such that its duration is substantially the same as the sum of durations  406 ,  408 , and  410 . 
     In an embodiment, the controller  101  determines that if an adjustment signal is sent at a certain time, then there would be a violation of t prep , that is, timestamp t 5  would be reached before the new batch of dialysate is mixed and ready. The controller  101  can determine in this case to delay the adjustment signal, mix a new batch of dialysate based on an old recipe, and then provide the buffered adjustment signal in a next period. This indicates that after timestamp t f , there is a maximum time t max  that the controller  101  can wait before sending the adjustment signals to the actuators  208  at timestamp t 2 . In an embodiment t max  can be determined to be the sum of durations  402 ,  404 ,  406 ,  408 , and  410  minus t prep . Since t max  depends on timestamp t 5 , in some embodiments, t max  is determined by the controller  101  based on flow rate of dialysate exiting the mixing chamber  204  and a volume of dialysate in the mixing chamber  204 . 
     In an embodiment, the controller  101  can also monitor and try to regularize t c , a time duration between when the controller  101  sends an adjustment signal and when the controller  101  obtains electrolyte measurements to ascertain effects of the adjustment signals on electrolyte concentration in the blood. 
       FIG. 5  is a flow diagram for determining individualized dialysate recipes or prescriptions for a patient, according to an embodiment of the disclosure.  FIG. 5  is a flow diagram illustrating a process  500  performed by a dialysis system, e.g., the hemodialysis system  100 , to determine the patient&#39;s dialysate recipes. At  502 , the hemodialysis system  100  loads a dialysate recipe from a patient profile. 
     In an embodiment, the hemodialysis system  100  may receive a chip card or a computer memory storage like a flash drive that contains dialysate recipes for the patient  210 . In an embodiment, the patient profile may be obtained from a database or centralized storage. By way of example, for a description of a system for securely distributing information, including medical prescriptions, within a connected health network, reference is made to US Pub. No. 2018/0316505A1 to Cohen et al., which is incorporated herein by reference. 
     The dialysate recipe for treatment is selected and loaded from the patient profile. In an embodiment, the dialysate recipe selected is a last recipe used from a previous treatment that the patient  210  went through. In another example, the dialysate recipe selected is a default recipe especially when the patient  210  has never undergone dialysis at the specific location. In another example, the dialysate recipe selected is a recipe determined based on trend analysis of previous dialysate recipes from the patient profile. In another example, the dialysate recipe selected is a recipe determined based on historical trend analysis on electrolyte measurements from the patient&#39;s previous dialysis treatments. 
     At  504 , the hemodialysis system  100 , via the dialysate mixing system  105 , mixes a first batch of dialysate based on the loaded recipe from  502 . 
     At  506 , the hemodialysis system  100  via the electrolyte composition monitor  200 , monitors blood electrolytes and adjusts dialysate recipes based on electrolyte measurements according to various embodiments of the disclosure. For example, the electrolyte composition monitor  200  monitors blood electrolytes and adjusts dialysate recipes as provided in the process  300 . During treatment, the hemodialysis system  100  creates a folder or a collection of dialysate entries within the patient profile for the current dialysis treatment. Within the folder, the hemodialysis system  100  can store one or more of dialysate recipe used, number of batches mixed that correspond to the dialysate recipe, and electrolyte measurements that led the dialysate recipe. 
     At  508 , after the dialysis treatment is completed, the hemodialysis system  100  ranks the dialysate recipes stored at  506 . In an embodiment, the dialysate recipes are ranked based on a number of dialysate batches made per recipe. In other words, if the hemodialysis system  100  determines the dialysate batches are effective (e.g., effective in reducing the electrolyte concentration(s) to the predefined range in  304 ), the hemodialysis system  100  may use the recipe again, which would increase the number of dialysate batches made using the recipe and would cause the hemodialysis system  100  to rank the dialysate recipe higher. In an embodiment, the dialysate recipes are ranked based on a trend analysis that compares similar dialysate recipes, then combines the number of batches for the similar dialysate recipes, and then ranks groups of dialysate recipes based on the combined number of batches. 
     In an embodiment, the similar dialysate recipes with the highest combined number of batches are analyzed to determine one representative recipe. The representative recipe can be determined via one or more statistical means, e.g., can be determined using an average, a median, a random selection, and so on. 
     At  510 , the hemodialysis system  100  stores the dialysate recipes with the highest number of batches in the patient profile. In an embodiment, a representative recipe determined according to embodiments of the disclosure is stored along with the dialysate recipes. 
       FIG. 6  is a block diagram of an example computer system  600 . For example, the controller  101  is an example of the system  600  described here. The system  600  includes a processor  610 , a memory  620 , a storage device  630 , and an input/output device  640 . Each of the components  610 ,  620 ,  630 , and  640  can be interconnected, for example, using a system bus  650 . The processor  610  processes instructions for execution within the system  600 . The processor  610  can be a single-threaded processor, a multi-threaded processor, or a quantum computer. The processor  610  can process instructions stored in the memory  620  or on the storage device  630 . The processor  610  may execute operations that facilitate performing functions attributed to the electrolyte composition monitor  200 . 
     The memory  620  stores information within the system  600 . In some implementations, the memory  620  is a computer-readable medium. The memory  620  can, for example, be a volatile memory like synchronous random access memory (SRAM) or a non-volatile memory like flash. 
     The storage device  630  is capable of providing mass storage for the system  600 . In some implementations, the storage device  630  is a non-transitory computer-readable medium. The storage device  630  can include, for example, a hard disk device, an optical disk device, a solid-date drive, a flash drive, magnetic tape, or some other large capacity storage device. The storage device  630  may alternatively be a cloud storage device, e.g., a logical storage device including multiple physical storage devices distributed on a network and accessed using a network. In some implementations, the information stored on the memory  620  can also be stored on the storage device  630 . 
     The input/output device  640  provides input/output operations for the system  600 . In some implementations, the input/output device  640  includes one or more of network interface devices (e.g., an Ethernet card), a serial communication device (e.g., an RS-232 10 port), and/or a wireless interface device (e.g., a short-range wireless communication device, an 802.11 card, a 3G wireless modem, or a 4G wireless modem). In some implementations, the input/output device  640  includes driver devices configured to receive input data and send output data to other input/output devices, e.g., a keyboard, a printer, and display devices (such as the touch screen  118 ). In some implementations, the input/output device  640  receives dialysate prescription (e.g., wirelessly) for processing by the hemodialysis system  100 . In some implementations, mobile computing devices, mobile communication devices, and other devices are used for sending dialysate prescriptions. 
     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.