System and method for producing fluid for peritoneal dialysis

Abstract

A system (1) for producing a fluid for peritoneal dialysis (PD), the system (1) comprising: a fluid path (2) comprising: two or more PD concentrate connectors (3a, 3b, 3c), each connector configured to be connected to a source of a PD concentrate fluid (4a, 4b, 4c); and an inlet connector (5a, 23a) configured to be connected to a fluid line (5, 11) arranged for transporting an effluent fluid from a patient; a forward osmosis (FO) unit (6) comprising a draw side (6a) and a feed side (6b) separated by a FO membrane (6c), the FO unit (6) being fluidly connected to the fluid path (2), wherein the FO unit (6) is configured to receive one or more PD concentrate fluids (4a, 4b) at the draw side (6a) and to receive the effluent at the feed side (6b), wherein, by means of an osmotic pressure gradient between the draw side (6a) and the feed side (6b), water is transported through the FO membrane (6c) from the effluent to the one or more PD concentrate fluids, thereby diluting the one or more PD concentrate fluids into a diluted PD concentrate fluid; a concentration sensor (8) configured to sense a concentration of the diluted PD concentrate fluid, or a weighing scale (72) for sensing a weight of the diluted PD concentrate fluid; and a control device (10) configured to: control a flow rate of the effluent fluid into the feed side (6b), control a flow rate of the one or more PD concentrate fluids (4a, 4b) into the draw side (6a) based on (i) the concentration sensed by the concentration sensor (8) or (ii) the weight sensed by the weighing scale (72) to produce the diluted PD concentrate fluid, and control a flow rate of a second or third concentrate (4c) into the diluted PD concentrate fluid to form a final PD fluid.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of peritoneal dialysis and to a system and method for producing fluid for peritoneal dialysis treatment. BACKGROUND

[0002] Peritoneal dialysis (PD) is a method for treating patients suffering from kidney failure. During PD, the patient's peritoneal cavity is filled with fresh PD fluid and waste and liquid is transported from the patient's blood to the fresh PD fluid via the patient's peritoneum. The used PD fluid is subsequently drained from the patient. There are several kinds of PD. In automated peritoneal dialysis (APD), a machine or cycler is used to fill the peritoneal cavity with fresh PD fluid and to automatically drain the used PD solution from the body after a specified dwell period. The procedure is repeated several times, usually during the night.

[0003] In continuous flow peritoneal dialysis (CFPD), a machine is used to provide a continuous flow of fresh PD fluid to the patient's peritoneal cavity and a continuous flow of used PD fluid from the patient. The APD systems on the market today use centrally manufactured PD fluid, which is shipped to the patient ready for use in bags stored at the patient's home.

[0004] Transport of PD fluid adds to the cost of treatment and has a negative impact on the environment. Storing PD fluid at the patient's home is very space demanding. The handling of PD fluid by the patient before treatment adds to the burden of the patient, many of whom find it heavy to place the PD fluid bags in the right place before the treatment starts. There is therefore a need to reduce the negative consequences listed above. SUMMARY

[0005] It is an object of the present disclosure to alleviate at least some of the drawbacks of the prior art. Another object is to provide a cost-effective solution for producing fluid for PD at the point of care. Yet another object is to provide a solution for producing fluid for PD at the point of care that consumes a small amount of water.

[0006] These and other objects are at least partially achieved by the system and method according to the independent claims and by the embodiments according to the dependent claims.

[0007] According to one aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the present disclosure relates to a system for producing a fluid for peritoneal dialysis (PD). The system comprises a fluid path having one or more PD concentrate connectors each configured to be connected to a source of PD concentrate fluid, and an inlet connector configured to be connected to a fluid line arranged for transporting an effluent fluid from a patient. The system further comprises a forward osmosis (FO) unit comprising a draw side and a feed side separated by a FO membrane. The FO unit is fluidically connected to the fluid path. The FO unit is configured to receive the one or more PD concentrate fluids at the draw side and to receive the effluent at the feed side, wherein, by means of an osmotic pressure gradient between the draw side and the feed side, water from the effluent is transported through the FO membrane to the one or more PD concentrate fluids. Thereby, the one or more PD concentrate fluids are diluted into a diluted PD concentrate fluid. The system further comprises a concentration sensor configured to sense a concentration of the diluted PD concentrate fluid, or a weigh scale for sensing a weight of the diluted PD concentrate fluid. The system further comprises a control device configured to control a flow rate of the effluent fluid into the feed side, to control a flow rate of the one or more PD concentrate fluids into the draw side based on (i) the concentration sensed by the concentration sensor or (ii) the weight sensed by the weigh scale, to produce the diluted PD concentrate fluid, and to control a flow rate of a second concentrate or a third concentrate into the diluted PD concentrate fluid to form a final PD fluid.

[0008] The proposed system can reuse water from the effluent, thereby reducing the need for new purified water. The complexity and cost of the purification unit can be reduced compared to using tap water to purify locally manufactured PD fluid, as the capacity of the purification unit can be reduced. The volume of fluid to be shipped can be reduced compared to centralized manufacturing and shipping of the entire fluid volume.

[0009] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the system comprises a concentration sensor configured to sense a concentration of the diluted PD concentrate fluid. The control device is configured to control the flow rate of the one or more PD concentrate fluids into the draw side based on the sensed concentration of the diluted PD concentrate fluid.

[0010] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the control device is configured to control the flow rate of the effluent fluid into the feed side and to control the flow rate of the one or more PD concentrate fluids into the draw side to a flow rate matching a specific production rate of the final PD fluid, to achieve a prescribed concentration of the one or more PD concentrate fluids in the final PD fluid.

[0011] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the control device includes a first pump configured to control a flow rate of the one or more PD concentrate fluids into the draw side.

[0012] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, (i) controlling a flow rate of the effluent fluid into the feed side, and (ii) controlling a flow rate of the one or more PD concentrate fluids to produce the diluted PD concentrate fluid are performed prior to treatment.

[0013] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the control device is configured such that the effluent fluid from the patient is transported for storage prior to treatment.

[0014] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the fluid path includes an osmotic agent connector configured to be connected to an osmotic agent source. The control device is configured to supply the osmotic agent from the osmotic agent source to the fluid path to achieve a prescribed concentration of the osmotic agent in the final PD fluid.

[0015] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the system includes another pump configured to control a flow rate of the osmotic agent from the osmotic agent source to the fluid path.

[0016] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the fluid path includes a water source connector positioned downstream of the FO permeate unit, wherein the water source is configured to be connected to a pure water source. The control device is configured to supply pure water from the pure water source to the diluted PD concentrate fluid to achieve a prescribed composition of the final PD fluid.

[0017] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the system is configured to sense a concentration of the final PD fluid. The control device is configured to control a flow rate of the diluted one or more PD concentrate fluids to achieve a prescribed composition of the final PD fluid based on the sensed concentration of the final PD fluid.

[0018] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the system includes a system pump configured to control a flow rate of the final PD fluid.

[0019] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the system includes a container fluidically connected or connectable to the fluid path, wherein the container is arranged to receive the diluted PD concentrate fluid.

[0020] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the system includes an effluent pump arranged to control a flow rate of effluent fluid into a feed side of the FO unit.

[0021] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the system includes a heater configured to heat fluid in the fluid path.

[0022] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the system includes an effluent container fluidically connected to the fluid path and the inlet connector, wherein the effluent container is arranged to collect effluent fluid received from the patient prior to being delivered into the feed side of the FO unit.

[0023] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the fluid path includes a circulation fluid path, and wherein the control device is configured to circulate the diluted PD concentrate fluid in the circulation fluid path until a mixing criterion of the diluted PD concentrate fluid is satisfied.

[0024] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, one of the one or more PD concentrate sources includes a fluid including one or more of lactic acid, acetic acid, citric acid, bicarbonate, KCl, MgCl2, CaCl2, and NaCl.

[0025] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, one of the PD concentrate fluids includes a higher concentration of a component solution (e.g., NaCl) than in a fully mixed version of the PD concentrate solution, while another of the PD concentrate fluids includes the remaining concentrate solution.

[0026] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the weigh scale is configured to operate with the diluted PD concentrate solution container, and includes a second weigh scale configured to operate with the one or more PD concentrate fluids.

[0027] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the system is a continuous flow peritoneal dialysis (CFPD) system, and includes a drain pump positioned and arranged to pump effluent from the patient to a location for delivery to the feed side of the FO unit.

[0028] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the control device includes a first pump configured to pump the one or more PD concentrate fluids from the diluted PD concentrate container and a second PD concentrate pump configured to pump the one or more PD concentrate fluids into the draw side of the FO unit.

[0029] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the system includes a line and a valve positioned and arranged to enable the initially but not fully diluted PD concentrate fluids to be redirected for delivery to the feed side of the FO unit.

[0030] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the system includes a device configured and arranged to generate a higher pressure on the feed side of the FO unit than on the draw side.

[0031] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the present disclosure includes a method for producing fluid for peritoneal dialysis (PD) in a system including a forward osmosis (FO) unit. The FO unit includes a draw side and a feed side separated by a FO membrane, the FO unit configured to receive one or more PD concentrate fluids at the draw side and to receive an effluent fluid from a PD patient at the feed side to transport water from the effluent to the one or more PD concentrate fluids through the FO membrane by means of an osmotic pressure gradient between the draw side and the feed side, thereby diluting the one or more PD concentrate fluids into a diluted PD concentrate fluid. The method includes controlling a flow rate of the effluent fluid into the feed side of the FO unit and controlling a flow rate of the one or more PD concentrate fluids into the draw side based on a concentration sensed by a concentration sensor or a weight sensed by a weigh scale to produce the diluted PD concentrate fluid. The method further includes controlling a flow rate of a second concentrate into the diluted PD concentrate fluid to form a final PD fluid.

[0032] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the method includes controlling the flow rate of the effluent and the flow rate of the one or more PD concentrate fluids prior to the treatment and controlling the flow rate of the second concentrate or the third concentrate is performed during the treatment.

[0033] According to another aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the method includes controlling a flow rate of the effluent fluid into the feed side of the FO unit; and controlling a flow rate of the one or more PD concentrate fluids into the draw side to a flow rate that matches a specific production rate of the final PD fluid to achieve a prescribed concentration of the one or more PD concentrate fluids in the final PD fluid.

[0034] According to another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the method includes sensing a concentration of the diluted PD concentrate fluid and controlling a flow rate of the one or more PD concentrate fluids into the draw side based on the sensed concentration of the diluted PD concentrate fluid.

[0035] According to another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the method includes controlling a flow rate of the one or more PD concentrate fluids into the draw side using a first pump.

[0036] According to another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the method includes supplying a permeate from a permeate source to the fluid path to achieve a prescribed concentration of the permeate in the final PD fluid.

[0037] According to another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the supplying includes controlling a flow rate of the permeate from the permeate source to the fluid path using another pump.

[0038] According to another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the method includes supplying purified water from a purified water source located downstream of the FO permeation unit to the diluted PD concentrate fluid to achieve a prescribed composition of the final PD fluid.

[0039] According to another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the method includes sensing a concentration of the final PD fluid and controlling a flow rate of the one or more PD concentrate fluids into the draw side based on the sensed concentration to achieve a prescribed composition of the final PD fluid.

[0040] According to another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the method includes controlling a flow rate of the final PD fluid using a system pump.

[0041] According to another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the method includes directing the diluted PD concentrate fluid into a container.

[0042] According to another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the method includes controlling a flow rate of the effluent fluid into the feed side using an effluent pump.

[0043] According to another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the method includes heating fluid in the fluid path using a heater.

[0044] According to another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the method includes collecting the effluent fluid in an effluent container prior to delivering the effluent fluid to the feed side of the FO unit.

[0045] According to yet another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the method comprises circulating the diluted PD concentrate fluid in the circulating fluid path until a mixing criterion of the diluted PD concentrate fluid is met.

[0046] According to yet another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the disclosure relates to a computer program comprising instructions causing the system according to the first aspect to perform the steps of the method according to the second aspect.

[0047] According to yet another aspect of the disclosure, which can be combined with any other aspect or portion thereof, the disclosure relates to a computer readable memory having stored thereon the computer program of the third aspect.

[0048] Additional features and advantages are described in, and will be apparent from, the following DETAILED DESCRIPTION and the Figures. The features and advantages described herein are not all-inclusive and are specifically, numerous additional features and advantages which will be readily apparent to one of ordinary skill in the art in view of the Figures and Description. Moreover, any particular embodiment does not necessarily have all of the described advantages, and specific embodiments can not necessarily exhibit all of the described advantages. Furthermore, no particular embodiment is required to have each of the described advantages, and specific embodiments can not necessarily exhibit all of the described advantages. Furthermore, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes and, accordingly, can not be intended to limit the scope of the inventive subject matter. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 different embodiments of systems for producing fluid for PD according to some embodiments.

[0050] Figure 2 is a flowchart of a method for producing fluid for PD according to some embodiments. DETAILED DESCRIPTION

[0051] In the following disclosure, several embodiments of systems and methods for producing fluid for treatment of peritoneal dialysis (“PD”) will be described. Embodiments can each utilize forward osmosis (FO) to dilute one or more PD concentrates using water from used PD fluid or “effluent” that is transported across a FO membrane. Water from the effluent is reused to mix with the PD concentrate to provide new PD fluid. This solution can be used for different variants of automated PD, including online mixing of PD fluid and batch mixing of PD fluid. Performance testing of the system has shown that the need for new, pure water can be reduced by 50-70% or more compared to systems that do not use the present structure and method.

[0052] refer to Figure 1 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 , multiple systems for generating fluids for PD are described herein. The same reference numerals in all figures may not be described in every embodiment, but include all structures, functions, and alternatives described.

[0053] Figure 1 A system 1 according to some embodiments of the present disclosure is shown. The system 1 includes a fluid path 2, a plurality of connectors, a forward osmosis (FO) unit 6, and a control device 10. The fluid path 2 may be enclosed in a housing ( Figure 1 (not shown). Fluid path 2 can be part of a device or a disposable system. Fluid path 2 includes multiple fluid lines. Fluid path 2 can include some or all of the fluid lines described herein. Connectors include one or more PD concentrate connectors 3a, 3b, 3c. Each PD concentrate connector is configured to connect to a source of PD concentrated fluid 4a, 4b, 4c. As an optional PD concentrated fluid 4b in Figure 1 , and indicates that more than one draw-side concentrate can be provided. As described herein, PD concentrate fluid 4a can be considered a first concentrate fluid, PD concentrate fluid 4b (if provided) can be considered a second concentrate fluid, and PD concentrate fluid 4c can be considered a second or third concentrate fluid, depending on whether PD concentrate fluid 4b is provided. The source of PD concentrate fluid is typically a bag of PD concentrate. Each PD concentrate connector is then configured to connect to a corresponding connector provided with a PD concentrate bag. The connector further includes an inlet connector 5a. Inlet connector 5a is typically configured to connect to fluid line 5, which is arranged to convey outflow fluid from the patient.

[0054] The FO unit 6 comprises a draw side 6a and a feed side 6b separated by a FO membrane 6c. The FO unit 6 is fluidly connected to the fluid path 2. The FO unit 6 is configured to receive the one or more PD concentrate fluids 4a, 4b at the draw side 6a and to receive the effluent at the feed side 6b to transport water from the effluent to the one or more PD concentrate fluids through the FO membrane 6c by means of an osmotic pressure gradient between the draw side 6a and the feed side 6b. Thus, the one or more PD concentrate fluids are diluted into a diluted PD concentrate fluid. The FO membrane 6c is a water permeable membrane. The FO membrane 6c typically has a pore size in the nanometer (nm) range, e.g. from 0.5 to 5 nm or less, depending on the solutes intended to be rejected. It separates the effluent (feed side) and the PD concentrate (draw side). The different sides can also be referred to as compartments. The fluids in these sides typically flow in countercurrent flow, but can also flow in alternating co-current flow. In some embodiments, the fluids flow single pass, where the fluids only pass through the FO unit 6 once. Suitable FO units for the FO unit 6 are provided by Aquaporin TM , Asahi KASEI TM , Berghof TM , CSM TM , FTSH2O TM , Koch Membrane Systems TM , Porifera TM , Toyobo TM , and Toray TM .

[0055] Water in the effluent is transported through the FO membrane by means of a driving force created by the osmotic pressure gradient between the effluent (feed solution) and the one or more PD concentrate fluids (draw solution). This means that the effluent, which initially and finally has the same osmotic pressure based PD fluid, will become more concentrated throughout the FO process. On the other hand, the one or more PD concentrate fluids will be more diluted throughout the FO process. The FO membrane is a water treatment membrane that is able to facilitate the forward osmosis process. It is a semi-permeable membrane that allows water to flow from the low concentrate side (feed side) to the high concentrate side (draw side). The FO membrane typically comprises a thin rejection layer (or active layer) and an underlying porous support. Also, the FO membrane can have a pore size in the nanometer (nm) range, e.g. from 0.5 to 5 nm or less, depending on the solutes intended to be rejected. The FO membrane 6c is typically designed to have more or less exclusively selective for water molecules, which enables the membrane to separate water from all other contaminants. The geometry of the membrane can be flat fiber, tubular fiber or hollow fiber.

[0056] In more detail, the first PD concentrate bag 4a is connected to the first PD concentrate connector 3a via a first bag connector. The first fluid line 21 is fluidly connected between the first PD concentrate connector 3a and the inlet port of the draw side 6a. Thus, the first fluid line 21 connects the first PD concentrate connector 3a and the draw side 6a. An optional additional PD concentrate bag 4b is connected to an additional PD concentrate connector 3b via an optional bag connector. A fluid line 21a can be fluidly connected between the additional PD concentrate connector 3b and the first fluid line 21. Thus, the fluid line 21a connects the additional PD concentrate connector 3b and the first fluid line 21. It should be understood that the flow through the first fluid line 21 and the fluid line 21a can be controlled by means of one or more valves and / or one or more pumps arranged to the first fluid line 21 and the fluid line 21a. For ease of illustration, these components are not shown in Figure 1

[0057] The second fluid line 22 is fluidly connected between the outlet of the draw side 6a and the outlet connector 11a. Thus, the second fluid line 22 fluidly connects the draw side 6a and the outlet connector 11a. The outlet connector 11a is configured to be connected to a corresponding connector of a fluid line 11 configured to deliver the final PD fluid directly to a catheter of a patient, a cycler for pumping the fluid to a patient or a batch processing container. The third fluid line 25 is connected between the inlet connector 5a and the inlet of the supply side 6b. Thus, the third fluid line 25 fluidly connects the inlet connector 5a and the supply side 6b. Optionally, the effluent can be collected in an effluent container 15 before the effluent is fed into the supply side 6b. Thus, the effluent container 15 can be arranged to collect the effluent fluid received from the patient before delivering the effluent fluid received from the patient into the supply side 6b. A fluid line 25a then connects the effluent container 15 to the third fluid line 25. Thus, the effluent container 15 is fluidly connected to the fluid path 2 and the inlet connector 5a.

[0058] Figure 1 ​An effluent pump 44 is arranged to control the flow rate of effluent fluid entering the supply side 6b. The effluent pump 44 is also arranged to control the flow rate of effluent into the effluent container 15. Furthermore, the effluent pump 44 is arranged to control the flow rate of effluent from the effluent container 15 into the supply side 6b. Here, the effluent pump 44 is arranged to control the flow rate of effluent fluid in the third fluid line 25. The fourth fluid line 26 is connected between the outlet of the supply side 6b and the drain connector 12a. Thus, the fourth fluid line 26 connects the supply side 6b and the drain connector 12a. The drain connector 12a is configured to connect to a corresponding connector of a drain line (not shown), which can be connected to a drain port to remove effluent after use. A connecting fluid line 56 can be connected between the second fluid line 22 and the fourth fluid line 26. For example, the connecting fluid line 56 is used during fluid discharge during flushing or cleaning, or as an overflow drain, and can be controlled via a valve (not shown).

[0059] The system 1 further comprises a container 9 fluidically connected or connectable to the fluid path 2. The container 9 is arranged to receive the diluted PD concentrate fluid. A fifth fluid line 18 is connected to the first port 9a ( Figure 3 and Figure 4 ) and the second fluid line 22. Thus, the fifth fluid line 18 connects the first port 9a of the container 9 and the second fluid line 22. The sixth fluid line 27 is connected to the second port 9b ( Figure 3 and Figure 4 ) between the second fluid line 22. Thus, the sixth fluid line 27 connects the second port 9b of the container 9 and the second fluid line 22. The fifth fluid line 18 is connected to the second fluid line 22 at a first point of the second fluid line 22. The sixth fluid line 22 is connected to the second fluid line 22 at a second point of the second fluid line 22. The first pump 41 is arranged to pump the fluid in the second fluid line 22. Figure 1 In FIG, the first pump 41 is arranged between the first point and the second point of the second fluid line 22. The first pump 41 is also configured to control the flow rate of the one or more PD concentrate fluids into the extraction side 6a.

[0060] The first concentration (e.g., conductivity) sensor 8 is arranged to sense a concentration of fluid in the second fluid line 22 between a first point and a second point of the second fluid line 22. The fluid path 2 includes a circulation fluid path 16 that includes the container 9, the fifth fluid line 18, the sixth fluid line 27, and the second fluid line 22 from the first point to the second point. The fluid path 2 also includes a water source connector 3d configured to be connected to a source of pure water 7. An eighth fluid line 28 is connected between the water source connector 3d and the second fluid line 22. Thus, the eighth fluid line 28 fluidly connects the water source connector 3d and the second fluid line 22. The fluid path 2 also includes a permeant connector 3c configured to be connected to a source of permeant 4c. A ninth fluid line 29 is connected between the permeant connector 3c and the second fluid line 22. Thus, the ninth fluid line 29 fluidly connects the permeant connector 3c and the second fluid line 22.

[0061] The second pump 42 is configured to control a flow rate of permeant from the source of permeant 4c to the fluid path 2. The second pump 42 is configured to control a flow rate of permeant in the ninth fluid line 29. The heater 14 is configured to heat fluid in the fluid path 2. In Figure 1 The heater 14 is configured to heat fluid in the second fluid line 22 downstream of the source of water 7 but upstream of the source of permeant 4c. Alternatively, the heater 14 can be arranged to heat fluid at any other location along the second fluid line 22. The system pump 43 is configured to control a flow rate of final PD fluid in the second fluid line 22. The second concentration sensor 13 is configured to sense a concentration of the final PD fluid in the second fluid line 22.

[0062] The concentration sensor can include, for example, a conductivity sensor configured to sense a conductivity of the fluid, or a resistivity sensor configured to sense a resistivity of the fluid. Even if, for example, a resistivity sensor is used, the sensed value can be converted to a conductivity value if needed. Likewise, a conductivity value can be converted to a resistivity value.

[0063] The system 1 further comprises a control device 10 configured to control the flow rate of the outflow fluid into the supply side 6b. For example, outflow fluid control is performed by means of an effluent pump 44. In some embodiments, the control device 10 is further configured to control the flow rate of the one or more PD concentrated fluids into the extraction side 6a to a flow rate that matches a specific production rate of the final PD fluid with a specified concentration of the one or more PD concentrated fluids. The final PD fluid has a previously specified or predetermined composition of PD concentrate and water. Thus, the specified concentration of the one or more PD concentrates that the final PD fluid should have is also known. The final PD fluid is the PD fluid that is ready for delivery to the patient's peritoneal cavity. The production rate can be batched, i.e., a specific or specified volume of the final PD fluid is produced. The specific volume constitutes a batch. Alternatively, the production mode comprises a continuous or sustained flow rate of the final PD fluid.

[0064] The control device 10 is configured to add the correct amount of one or more PD concentrates to the fluid path 2 to achieve the specified final composition of the final PD fluid. During the forward osmosis process in the FO unit 6, water from the effluent is transferred to the one or more PD concentrates. The one or more PD concentrates are then diluted into diluted PD concentrates in the FO unit 6 and output from the FO unit 6 as diluted PD concentrated fluid into the second fluid line 22. The control device 10 is configured to control the flow rate of the one or more PD concentrated fluids into the extraction side 6a based on the sensed concentration of the diluted PD concentrated fluid.

[0065] It is desired to extract as much water as possible from the effluent to produce the final PD fluid. In some embodiments, to achieve this extraction, the flow rate of the effluent into the feed side 6b is matched with the flow rate of the PD concentrate(s) into the draw side 6b. Based on the desired composition of the PD fluid, the concentration of the PD concentrate and the amount of effluent at hand and the time available for the FO session, the flow rate is initially set to an approximate flow rate. The amount of PD concentrate in the desired composition PD fluid and the concentration of the PD concentrate(s) are known beforehand or predetermined. Thus, for each batch of final PD fluid, the amount of PD concentrate(s) to be supplied into the draw side 6a is known. The amount of effluent can also be known from how much effluent the effluent pump 44 has pumped into the effluent bag 15 or by weighing the effluent bag 15. For example, if 100 milliliters of PD concentrate is included in a batch of final PD fluid, then 100 milliliters will be supplied from the PD concentrate source 4a and pumped into the FO unit 6 by means of the first pump 41. During the same time period, as the PD concentrate is pumped into the FO unit (draw side 6a), effluent is pumped from the effluent source 15 into the FO unit (feed side 6b). The amount of effluent is typically larger than the amount of PD concentrate, for example, 2000 ml of effluent compared to 100 ml of PD concentrate. The effluent is then pumped into the feed side 6b at a flow rate that is 20 times larger than the flow rate of the PD concentrate(s) into the draw side 6a.

[0066] In some embodiments, the diluted PD concentrate is directed to the container 9. By varying the speed of the first pump 41, the flow rate of the PD concentrate(s) into the draw side 6a can be varied so that the desired product of the concentration and the volume of the diluted PD concentrate can be reached. Thus, the desired product of the concentration and the volume is the desired amount of PD concentrate that should be included in the batch. The concentration sensor 8 is configured to sense the concentration of the diluted PD concentrate. The sensed concentration together with the flow rate provided by the first pump 41 can be used to calculate the amount of PD concentrate that is pumped to the container 9. The sensed concentration can also be used to control the flow rate of the PD concentrate(s) into the draw side 6a by the first pump 41. It can then be ensured that the correct amount of PD concentrate(s) is supplied for the desired production rate. Alternatively, the control device 10 comprises a pump (not shown) that can be operated with the first fluid line 21 to pump the PD concentrate(s) into the draw side 6b. This pump can then directly control the flow rate of the PD concentrate(s) into the draw side 6a. This pump can then pump the PD concentrate into the draw side 6b at a flow rate that is set to reach the desired product of the concentration and the volume of the diluted PD concentrate. Subsequently, the diluted PD concentrate is pumped into the container 9 by means of the first pump 41 and collected in the container 9. The control device 10 typically uses a valve (not shown) to control the flow of the diluted PD concentrate into the container 9. Figure 1The diluted PD concentrate is directed into the container 9.

[0067] Thereafter, the control device 10 is configured to circulate the diluted PD concentrate fluid in the circulation fluid path 16 until a mixing criterion of the diluted PD concentrate fluid is met. For example, the mixing criterion can include that the sensed concentration has a value within a predetermined interval for a predetermined time. After a batch of diluted PD concentrate has been collected in the container 9, the diluted PD concentrate solution can then be dispensed from the container 9 by means of the first pump 41 at a flow rate that matches or corresponds to a production rate of the final PD fluid. The production rate in turn can correspond to producing a certain batch (volume) of PD fluid within a certain time. Thus, the diluted PD concentrate solution is pumped with the first pump 41 to have a flow rate V P1 (ml / min) in the second fluid line 22 towards the system pump 43. The system pump 43 is typically configured to pump at a constant flow rate V sp ml / min, which is determined using the required production rate. The control device 10 is further configured to supply pure water from the pure water source 7 to the diluted PD concentrate fluid to reach a prescribed composition of the final PD fluid.

[0068] In one embodiment, the one or more PD concentrate solutions introduced into the draw side 6a can include both a permeant fluid and a buffer concentrate fluid having a different composition than the permeant fluid. For example, the permeant is glucose. The water supplied from the water source 7 to the second fluid path 22 will then have a flow rate of V sp minus V P1 Thus, the diluted PD concentrate fluid is further diluted by water to produce the final PD fluid. Alternatively, only one PD concentrate solution, typically the buffer concentrate solution, is introduced into the draw side 6a, while the permeant fluid is introduced downstream of the FO unit 6 via a ninth fluid line 29. The second pump 42 pumps the permeant into the second fluid line 22 at a flow rate of V P2 ml / min. The control device 10 is configured to supply the permeant from the permeant source 4c to the fluid path 2 to reach a prescribed concentration of the permeant 4c in the final PD fluid. The water supplied from the water source 7 to the second fluid path 22 will then have a flow rate of V sp minus V P1 minus V P2 Thus, the diluted PD concentrate fluid is further diluted, after which the permeant is added to the solution and the final PD fluid is produced. The flow rate V P1 of the diluted PD concentrate solution can depend on the concentration of the diluted PD concentrate solution and the desired composition of the final PD fluid.

[0069] Generally, the higher the concentration of the diluted PD concentrate, the lower the flow rate V P1 of the first pump 41, so that more water will be supplied to the diluted PD concentrate for further dilution. Thus, by changing the flow rate V P1 , the amount of water added from the water source 7 is changed.

[0070] One or more of the PD concentrate sources 4a comprises a fluid comprising one or more of ions and / or salts, e.g. lactic acid, acetic acid, citric acid, bicarbonate, KCI, MgCI2, CaCI2, NaCI. For example, one PD concentrate source can comprise a fluid comprising a buffer, e.g. one or more of lactic acid, citric acid, acetic acid and bicarbonate. When diluted with final use water and possibly other PD concentrate(s), the fluid becomes the final PD fluid, which has a pH value suitable for PD treatment, as well as one or more of KCI, MgCI2, CaCI2and NaCI. The final PD fluid can be formed to have a standard glucose level, e.g. 1.36% or 2.27% glucose.

[0071] The system 1 is further configured to sense the concentration of the final PD fluid with the second concentration sensor 13. The control device 10 is configured to control the flow rate of the diluted PD concentrate fluid(s) based on the sensed concentration of the final PD fluid to reach a prescribed composition of the final PD fluid. Thus, the sensed concentration can be used to fine tune the flow rate of the first pump 41 to reach the final composition, and thus the final concentration of the final PD fluid. Alternatively, the flow rate delivered with the second pump 42 can be fine tuned to reach the final composition, and thus the final concentration of the final PD fluid. The control device 10 further comprises a control unit 40 comprising a processor and a memory. The memory typically stores a program which, when executed by the processor, controls the system 1 as described herein. The control unit 40 can further comprise a communication interface which enables the control unit 40 to communicate data and signals to and from components of the system 1, e.g. sending control signals to valves and pumps, and receiving sensed data from concentration sensors and feedback signals from valves and pumps.

[0072] The described valves are typically on / off valves. The valves can be two-way valves or three-way valves.

[0073] Figure 2 is a flow chart of a method according to some embodiments of the present disclosure. The method can be implemented as instructions of a computer program and saved in the memory of the control unit 40. The flow chart of Figure 2 illustrates the method.

[0074] The flow chart discloses a method for producing a fluid for peritoneal dialysis (PD) in a system comprising a forward osmosis (FO) unit 6. The system can be any one of the systems 10 as shown herein. Blocks shown in dashed lines correspond to alternative or optional functions or procedures. In the embodiment shown, at SI the method collects the effluent fluid in an effluent container 15 before the effluent fluid is delivered into the feed side 6b. Alternatively, the effluent has already been collected into the container 15. In another alternative, the effluent is continuously provided to the system 10 from the patient via the effluent line 5 on-line. At S2, the method further comprises controlling the flow rate of the effluent fluid into the feed side 6b of the FO unit 6. At S2, the controlling comprises using the effluent pump 44 to control the flow rate of the effluent fluid into the feed side 6b. The speed of the effluent pump is typically configured to provide a predetermined flow rate of the effluent into the feed side 6b.

[0075] At S3, the method further comprises controlling the flow rate of the one or more PD concentrate fluids 4a, 4b into the draw side 6a to achieve a flow rate that matches the specified production rate of the final PD fluid with the prescribed concentration of the one or more PD concentrate fluids. Thus, a diluted PD concentrate is obtained such that when water (sometimes a permeate) is subsequently added downstream of the diluted PD concentrate, the final PD fluid with the prescribed composition is obtained. At S3, the controlling can comprise using the first pump 41 to control the flow rate of the one or more PD concentrate fluids into the draw side 6a.

[0076] At S4, the method can further comprise sensing the concentration of the diluted PD concentrate fluid and controlling the flow rate of the one or more PD concentrate fluids into the draw side 6a by means of the first pump 41. The method can comprise sensing the concentration with the first concentration sensor 8 and controlling the speed of the first pump 41 such that the diluted PD concentrate has the required product of concentration and volume.

[0077] At S5, the method can thereafter comprise directing the diluted PD concentrate fluid to a container 9. The diluted PD concentrate can then be collected in the container 9 until a predetermined amount of the one or more PD concentrate fluids has been pumped into the draw side 6a. At S6, the method comprises circulating the diluted PD concentrate fluid in the circulating fluid path 16 until a mixing criterion of the diluted PD concentrate fluid is met. When a batch of the final PD fluid is to be produced, the diluted PD fluid is then pumped into the second fluid line 22 and towards the system pump 43 with the first pump 41. Alternatively, the diluted PD concentrate fluid is not directed to the container 9 but is directed to continue flowing in the second fluid line 22, whereby the final PD fluid can be provided in a continuous flow fashion.

[0078] At S7, the method can include supplying PD concentrate from source 4c (e.g., a permeate from a permeate source 4c) into the fluid path 2 to achieve a prescribed concentration of permeate 4c in the final PD fluid. The permeate can be added as one of the one or more PD concentrate fluids upstream of the FO unit 6. Alternatively, the permeate is supplied into the diluted PD concentrate fluid downstream of the FO unit 6. The supply of permeate at S7 can then include controlling the flow rate of the permeate from the permeate source 4c to the fluid path 2 with the second pump 42. To produce the final PD fluid, water is added to the fluid being mixed. At S8, the method includes supplying purified water from a purified water source 7 downstream of the FO permeate unit 6 into the diluted PD concentrate fluid to achieve a prescribed composition of the final PD fluid.

[0079] To produce the final PD fluid, at S9, the method includes controlling the flow rate of the final PD fluid with the system pump 43. In some embodiments, at S10, the method senses the concentration of the final PD fluid with the second concentration sensor 13, and in S3, controls the flow rate of the one or more PD concentrate fluids into the draw side 6a to achieve a prescribed composition of the final PD fluid based on the sensed concentration. The sensed composition, and thus the sensed concentration, is fine-tuned to the prescribed composition.

[0080] To provide a final PD fluid that can be directly introduced into the peritoneal cavity of a patient, at Sll, the method includes heating the fluid in the fluid path 2 with the heater 14. The heater 14 can also be used to sterilize the fluid path 2 of the system 1.

[0081] In combination Figure 3 and Figure 4 Alternative APD systems 1 employing FO water reuse from the effluent are shown and described, each under the control of the control unit 40. Figure 3 A system 1 with on-line PD fluid production is shown. The system 1 in Figure 3 may be modified to perform continuous flow peritoneal dialysis (CFPD), where the PD fluid to the patient can be continuous or intermittent, but without a dedicated dwell period and the effluent is reused. Figure 4 A system 1 with batched PD fluid production is shown.

[0082] Figure 1 , Figure 3 and Figure 4The system 1 in each of the following uses a buffer solution as the draw solution. In one embodiment, a buffer solution is used as the draw solution because its concentration is easily detected based on conductivity when diluted. This principle can be used in all of the following embodiments of system 1 because the dilution ratio of the buffer solution after the FO period will be unknown. If a glucose concentrate is used as the draw solution, its dilution ratio after the FO period will be unknown, where the system will have to rely on the relatively weak effect of glucose on conductivity or glucose concentration measurements (e.g., by a refractometer) during dosing to the mixing system. Another advantage of using a buffer solution as the draw solution is that it has about twice the osmotic pressure of a glucose concentrate, thus creating twice the high osmotic pressure during the FO period. Different components of the buffer solution can be used in different versions of system 1 described herein (e.g., different nominal dilution ratios, buffer systems, etc.).

[0083] Figure 3 The system 1 in each of the following is explained together with a suggested sequence for producing fluid for a PD, including a diluted concentrate fluid and a final PD fluid. For the combination of Figure 1 The same components described for the system in Figure 3 The system 1 in each of the following has the same reference numerals. Figure 3 A number of valves are also shown. Such valves include: a first valve 32 operable with the second fluid line 22 downstream of the second point of the second fluid line 22; a second valve 31 operable with the second fluid line 22 upstream of the first point of the second fluid line 22; a third valve 33 operable with the fifth fluid line 18; a fourth valve 34 operable with the sixth fluid line 27; a fifth valve 35 operable with the third fluid line 25 upstream of the inlet of the feed side 6a; a sixth valve 37 operable with the third fluid line 25 upstream of the fifth valve 35 and just downstream of the inlet connector 5a; a seventh valve 30 operable with the second fluid line 22 just upstream of the outlet connector 11a; an eighth valve 39 operable with a fluid line fluidically connected between the second fluid path 22 (between the second concentration sensor 13 and the seventh valve 30) and the drain connector 12a; a ninth valve 38 operable with an overflow fluid line connected between the uppermost portion of the mixing chamber 46 and the fourth fluid line 26; and a tenth valve 36 (a three-way valve) arranged to direct effluent from the third fluid line 25 (via the fluid line 23) to the effluent container 15, or from the effluent container 15 (via the fluid line 24) to the third fluid line 25, or from the third fluid line 25 back to the third fluid line 25 without passing through the effluent container 15, where the effluent container 15 is bypassed.

[0084] The pumps in each version of the system 1 described herein can be volumetric pumps, such as piston pumps. The sequence of the system 1 can comprise one or more of the following steps.

[0085] 1. Perform initial priming, including system priming and level adjustment of the mixing chamber 46 and temperature and fluid composition mixing stabilization. During this first step, valves 31, 32, 37 and 38 are open, valves 30, 33, 34, 35, 36 and 39 are closed. Pumps 41, 42, 43 and 44 are running, the level sensor (LS) is active to sense the level in the mixing chamber 46, the temperature sensor 51 is used to sense the temperature of the fluid in the second fluid line 22 downstream of the addition point of the glucose concentrate into the second fluid line, and the first pressure sensor 53 is used to sense the pressure in the third fluid line 25 just downstream of the sixth valve 37.

[0086] 2. Perform composition / temperature stabilization using buffer concentrate. Then dose the buffer concentrate using conductivity feedback, while dosing glucose open loop. During this stabilization step, valves 31, 32, 39 are open, valves 30, 33, 34, 35, 36, 37 and 38 are closed. As in the previous step, pumps 41, 42 and 43 are running, the level sensor (LS) is active, and the temperature sensor 51 is used to sense the temperature. In addition, the second concentration sensor 13 is used to sense the conductivity.

[0087] 3. Perform first fill using buffer concentrate. During this step, valves 30, 31, 32 are open, valves 33, 34, 35, 36, 37, 38 and 39 are closed. As in the previous step, pumps 41, 42 and 43 are running, the level sensor (LS) is active, the temperature sensor 51 is used to sense the temperature, and the second concentration sensor 13 is used to sense the conductivity. In addition, the second pressure sensor 52 is used to sense the pressure.

[0088] 4. Perform first dwell, with FO period if sufficient amount of effluent was collected during initial priming, see also step 7. Otherwise, during the first dwell, all valves are closed. No components are running.

[0089] 5. Perform drain and composition / temperature stabilization (if FO phase was performed in section 4, use diluted buffer (diluted PD concentrate fluid), otherwise use buffer concentrate). During this stabilization step, only with buffer concentrate, valves 31, 32, 37, 39 are open, valves 30, 33, 34, 35, 36 and 38 are closed. Pumps 41, 42, 43 and 44 are running, level sensor (LS) is active, temperature is sensed with temperature sensor 51, conductivity is sensed with second concentration sensor 13, and pressure is sensed with first pressure sensor 53. If diluted buffer concentrate is used, valves 32, 33, 37, 39 are open, valves 30, 31, 34, 35, 36 and 38 are closed. Pumps 41, 42 and 43 are running, level sensor (LS) is active, temperature is sensed with temperature sensor 51, conductivity is sensed with second concentration sensor 13, and pressure is sensed with first pressure sensor 53.

[0090] 6. Perform second fill (if FO phase was performed in section 4, use diluted buffer, otherwise use buffer concentrate). During this fill step, only with buffer concentrate, valves 30, 31, 32 are open, valves 33, 34, 35, 36, 37, 38 and 39 are closed. Pumps 41, 42 and 43 are running, level sensor (LS) is active, temperature is sensed with temperature sensor 51, conductivity is sensed with second concentration sensor 13, and pressure is sensed with second pressure sensor 52. If diluted buffer concentrate is used, valves 30, 32, 33 are open, valves 31, 34, 35, 36, 37, 38 and 39 are closed. Pumps 41, 42 and 43 are running, level sensor (LS) is active, temperature is sensed with temperature sensor 51, conductivity is sensed with second concentration sensor 13, and pressure is sensed with second pressure sensor 52.

[0091] 7. Perform dwell and FO phase. First pump 41 is used to pump buffer concentrate from bag 4a via draw side 6a of FO unit 6 to container 9. The concentration sensed with first concentration sensor 8 is used to calculate the amount of buffer concentrate pumped to container 9. The sensed concentration can also be used for flow control with first pump 41. Effluent pump 44 is used to pump effluent from effluent container 15 via feed side 6b of FO unit 6 to drain. During this step, valves 31, 34, 35 are open, valves 30, 32, 33, 37, 38, 39 are closed. First pump 41 and effluent pump 44 are running, and first concentration sensor 8 measures diluted buffer concentrate fluid (thus, diluted PD concentrate fluid).

[0092] 8. Reside and recirculate diluted buffer concentrate fluid to ensure uniformity (homogenous solution). Use first concentration sensor 8 to sense the concentration of the diluted buffer concentrate fluid, and thus its composition. During this step, valves 33 and 34 are open, and valves 30, 31, 32, 35, 36, 37, 38, and 39 are closed. First pump 41 is running, and first concentration sensor 8 measures the diluted buffer concentrate fluid (and thus, the diluted PD concentrate fluid).

[0093] 9. Perform drain and composition / temperature stabilization (using diluted buffer concentrate fluid). During this step, valves 32, 33, 37, 39 are open, and valves 30, 31, 34, 35, 36, and 38 are closed. Pumps 41, 42, 43, and 44 are running, level sensor (LS) is active, temperature is sensed with temperature sensor 51, conductivity is sensed with second concentration sensor 13, and pressure is sensed with first drain side pressure sensor 53.

[0094] 10. Perform third fill (using diluted buffer concentrate fluid). During this step, valves 30, 32, and 33 are open, and valves 31, 34, 35, 36, 37, 38, and 39 are closed. Pumps 41, 42, and 43 are running, level sensor (LS) is active, temperature is sensed with temperature sensor 51, conductivity is sensed with second concentration sensor 13, and pressure is sensed with second pressure sensor 52.

[0095] 11. Repeat steps 7 through 10 at least once.

[0096] Figure 3 The system 1 in FIG. 1 is shown as a durable / disinfectable system. The system can alternatively be made at least partially disposable. The volumetric pump can then be replaced by a peristaltic pump and a scale, flow meter, or other sensor for volumetric control. The buffer concentrate and effluent flow during the FO session is optimized to maximize buffer concentrate dilution (as this will minimize the need for new purified water during PD fluid production). During composition / temperature stabilization, waste fluid can be fed to the effluent bag instead of the drain to increase water reuse. Disposable bags can be used instead of internal tanks / vessels.

[0097] The current fluid volume in each container can be controlled instead using volumetric pumps. To determine the volume in the buffer concentrate bag, input from the first concentration sensor 8 can also be needed. The fresh water container 7 can be replaced with a water purification device. If disposable bags are used to hold fresh water and effluent, the water bag can be reused to serve as the effluent bag for the next treatment. If so, the fresh water remaining in the fresh water bag after the treatment is completed can be left in the bag and regenerated together with the effluent during the next treatment. It is also contemplated to save the last discharge effluent for water extraction at the initial phase of the next treatment. The concentration sensed with the first concentration sensor 8 can be used for feed forward control of the control unit 40, which can use the sensed concentration to control the first pump 41. The removable effluent container 15 to simplify the system 1. The drawback here is that the FO session then needs to be performed with the discharge effluent flow rate during the patient discharge, instead of the optimized effluent flow rate during dwell. This means that the total water reuse will be reduced. To be able to perform heat sterilization, the system 1 can be modified to be able to create a closed hot water path that allows sterilization of the entire system. If extended use of FO filters is to be adopted, the filters should be included in such a path.

[0098] In Figure 3 In an alternative embodiment, the effluent bag 15 is not present, and the fluid lines 23, 24 are omitted. The effluent pump 44 is then arranged to operate with the third fluid line 25. Alternatively, the three-way valve 36 directs the effluent back to the third fluid line 25 via the fluid lines 23, 24. Here, continuous flow peritoneal dialysis (CFPD) can be implemented, in which the PD fluid to the patient can be continuous or intermittent, but in which the PD fluid is mixed online using water extracted from the effluent.

[0099] The CFPD sequence in various embodiments comprises one or more of the following steps.

[0100] 1. The patient is completely emptied and a FO session is run on the effluent, in which the effluent pump 44 is used to pump effluent from the patient via the FO unit 6 to the drain. The first pump 41 pumps buffer concentrate via the FO unit 6 to the container 9. The concentration sensor 8 senses the concentration and determines the volume pumped by the first pump 41 to calculate the amount of buffer concentrate pumped to the container 9, and the volume pumped by the first pump 41 can also be used for flow control. In this step, the valves 31, 34, 36 and 37 are open, and the valves 30, 32, 33, 35, 38 and 39 are closed. The first pump 41 and the effluent pump 44 are running, the concentration sensor 8 senses the concentration, and the pressure sensor 53 senses the effluent inlet pressure.

[0101] 2. Prime fluid path 2 and adjust the level in mixing chamber 46. In this step, valves 31, 32, 38 are open, valves 30, 33, 34, 35, 36, 37, and 39 are closed. Pumps 41, 42, 43, and 44 are running, concentration sensor 8 senses concentration, and level sensor senses the level in mixing chamber 46.

[0102] 3. Stabilize composition and temperature. If available, use diluted buffer concentrate (diluted PD concentrate), otherwise use buffer concentrate (use PD concentrate). Then, use the concentration sensed with concentration sensor 8 as feed forward control, use the concentration sensed with second concentration sensor 13 as feedback, to dose buffer concentrate, and in open loop to dose osmotic agent from osmotic agent source 4c. If buffer concentrate is used, valves 31, 32, 39 are open, valves 30, 33, 34, 35, 36, 37, and 38 are closed. Pumps 41, 42, and 43, level sensor, heater 14, temperature sensor 51, and concentration sensors 8, 13 are running. If diluted buffer concentrate is used, valves 32, 33, 39 are open, valves 30, 31, 34, 35, 36, 37, and 38 are closed. Pumps 41, 42, and 43, level sensor, heater 14, temperature sensor 51, and concentration sensors 8, 13 are running.

[0103] 4. Fill the intended volume into the patient. If available, use diluted buffer concentrate, otherwise use buffer concentrate. If buffer concentrate is used, valves 30, 31, and 32 are open, while valves 30, 33, 34, 35, 36, 37, 38, and 39 are closed. Pumps 41, 42, and 43, level sensor, heater 14, temperature sensor 51, concentration sensors 8, 13, and second pressure sensor 52 are running.

[0104] If diluted buffer concentrate is used: valves 30, 32, and 33 are open, while valves 30, 31, 34, 35, 36, 37, 38, and 39 are closed. Pumps 41, 42, and 43 are running, level sensor, heater 14, temperature sensor 51, concentration sensors 8, 13, and second pressure sensor 52 are running.

[0105] 5. Continuous flow treatment. System pump 43 is set to pump the fill flow, effluent pump 44 is set to pump the drain flow. Ultrafiltration rate (UFR) is known from model and / or patient history, and the speed difference between the speed of system pump 43 and the speed of effluent pump 44 is set accordingly to keep the fill volume constant. In one embodiment, FO phase and mixing are continuous, as effluent is pumped through FO membrane 6c, and water is extracted from the filter to dilute the buffer concentrate. The diluted buffer concentrate is used for mixing. Then, the buffer concentrate is dosed using the concentration sensed with concentration sensor 8 as feed forward control, using the concentration sensed with second concentration sensor 13 as feedback, and wherein the osmotic agent from osmotic agent source 4c is dosed in open loop. In this step, valves 30, 31, 32, 36 and 37 are open, valves 33, 34, 35, 38 and 39 are closed. Pumps 41, 42, 43, 44 are running, while using level sensor, heater 14, temperature sensor 51, second concentration sensor 13, first pressure sensor 53 and second pressure sensor 52.

[0106] 6. Intermittent drain + refill. Perform complete drain to establish fill volume reference (prevent over / underfilling). Perform the following steps:

[0107] a. Completely empty patient with feedback from first pressure sensor 53. Run FO phase as per step 1, and diluted buffer concentrate is accumulated in container 9.

[0108] b. Compare the amount drained to the assessed amount, if needed, to adjust UFR assessment accordingly.

[0109] c. Repeat steps 4 and 5 (and possibly 6).

[0110] In Figure 3In the alternative system 1, the effluent flow to the FO membrane 6c during the FO phase is determined by the process settings (discharge flow rate and CFPD flow rate) and may be difficult to optimize for buffer concentrate dilution. The diluted buffer concentrate flow rate during CFPD is controlled by the first pump 41 and is therefore controlled by the control of the first pump. The diluted buffer concentrate flow rate during the full discharge is optimized to maximize buffer concentrate dilution (to minimize the need for new purified water during PD fluid generation). Internal tanks or containers can be used instead of disposable bags. The current fluid volume in each container, bag or tank is maintained by monitoring the positive displacement pump. To determine the volume (e.g., buffer concentrate) in the PD concentrate bag 4a, input from the concentration sensor 8 is used. The purified water container 7 can be replaced by a water purification device (not shown). The CFPD process can be performed using two single-lumen patient lines or one double-lumen patient line connected to the patient catheter (which can be a double-lumen catheter). The container 9 can be removed to simplify the system. A disadvantage is that the FO phase is disabled during the full discharge, resulting in reduced overall water reuse. To enable thermal disinfection, the system 1 is modified to be able to create a closed hot water path that allows disinfection of the entire system.If the extended use of the FO filter 6c is adopted, the FO membrane 6c is included in the fluid path 2.

[0111] Figure 4 The system 1 in FIG. 1 is explained together with a suggested sequence for producing fluids for PD (including diluted concentrate fluids and final PD fluids). Figure 1 and Figure 3 The same components in the system, Figure 4 The systems 1 in FIG. 1 have the same reference numerals. Figure 4 , a plurality of valves are shown. These valves include an eleventh valve 61 arranged to operate with the ninth fluid line 29, a twelfth valve 62 arranged to operate with the eighth fluid line 28, a thirteenth valve 63 arranged to operate with the third fluid line 25, a fourteenth valve 64 arranged to operate with the second fluid line 22, a fifteenth valve 65 arranged to operate with the third fluid line 25 just upstream of the inlet of the supply side 6a, a sixteenth valve 66 arranged to operate with the fluid line 24 to transfer effluent from the third fluid line 25 to the effluent container 15, and a seventeenth valve 67 arranged to operate with the fluid line 23 between the fluid line 24 and the third fluid line 25, wherein the fluid line 23 is arranged to transfer effluent from the effluent container 15 to the third fluid line 25 for transfer to the supply side 6b of the FO unit 6.

[0112] Figure 4 The sequence includes one or more of the following steps.

[0113] Perform an initial drain:

[0114] 1. Drain effluent from patient to effluent bag. During this first step, valves 63, 66, 68 are open, and valves 61, 62, 64, 65, 67 are closed. During this step, effluent pump 44 is running, first scale 71 is arranged to measure the weight of effluent bag 15, and pressure sensor 52 senses the pressure in third fluid line 25. Thus, effluent pump 44 pumps effluent from the patient via third fluid line 25 and fluid line 24 into the effluent bag. First scale 71 can be provided with any version or embodiment of system 1 described herein.

[0115] Perform first fill:

[0116] 2. Heat the pre-filled PD fluid in container 9 without glucose and check the conductivity during recirculation. The PD fluid is recirculated in a recirculation path comprising fifth fluid line 18, a portion of second fluid line 22, sixth fluid line 27, and container 9. During this step, valve 64 is open, and valves 61, 62, 63, 64, 65, 66, 67, and 68 are closed. Heater 14 is running to heat the PD fluid to, for example, body temperature (e.g., 37°C). System pump 43 is running, and first concentration sensor 8 senses the conductivity. This step can also include adding glucose concentrate (for the first fill) if prescribed.

[0117] 3. Prime patient fluid line 5 / 11, then connect patient. During this step, valve 63 is open, and valves 61, 62, 64, 65, 66, 67, 68 are closed. System pump 43 is running, and second scale 72 is arranged to measure the weight of container 9. Second scale 72 can be provided with any version or embodiment of system 1 described herein. In addition, any version of system 1 described herein can include a third scale 73 positioned and arranged as shown to weigh the contents of any concentrate container (e.g., first PD concentrate (e.g., buffer) container 4a). Figure 4

[0118] 4. Fill patient with PD fluid. During this step, valve 63 is open, and valves 61, 62, 64, 65, 66, 67, 68 are closed. System pump 43 is running, second scale 72 is arranged to measure the weight of container 9, and first pressure sensor 52 senses the pressure in third fluid line 25.

[0119] Empty PD fluid from container 9:

[0120] ​5. Drain any remaining PD fluid from the container 9 to the effluent container 15 (to track the volume in the container 9 during the next batch preparation). During this step, valves 66 and 68 are open, and valves 61, 62, 63, 64, 65, 67 are closed. The system pump 43 is running, and the first pressure sensor 52 monitors pressure.

[0121] Prepare for the second fill batch:

[0122] 6. Perform the FO session, including pre-diluting the buffer concentrate (pre-diluted into diluted PD concentrate) before adding it to the container 9. Effluent is pumped from the effluent container 15 through the feed side 6b of the FO unit 6 to the drain 75. At the same time, the diluted buffer concentrate is pumped from the concentrate container 4a through the draw side 6a of the FO unit 6 to the container 9. The first concentration sensor 8 and the second weigh scale 72 are used to track the amount of buffer concentrate dosed into the container 9. The pump rates of the first pump 41 and the effluent pump 44 are controlled to maximize dilution of the buffer concentrate and to reach the target amount of buffer concentrate to be added to the container 9. During this step, valves 65, 67 are open, and valves 61, 62, 63, 64, 65, 66, 67, and 68 are closed. The first pump 41 and the effluent pump 44 are running, the first pressure sensor 51 senses pressure, the concentration sensor 8 senses concentration, and the first weigh scale 71 and the second weigh scale 72 measure the weight of the effluent and the diluted PD concentrate in the container 9.

[0123] 7. Add water from the water container 7 to the container 9. The amount of water added is matched to the dose of buffer concentrate and the sensed concentration of the fluid in the container 9. During this step, valve 62 is open, and valves 61, 63, 64, 65, 66, 67, 68 are closed. The system pump 43 is running, and the second weigh scale 72 measures the weight of the container 9.

[0124] 8. Recirculate, heat, and check conductivity. The diluted PD concentrate is recirculated in a recirculation path including the fifth fluid line 18, a portion of the second fluid line 22, the sixth fluid line 27, and the container 9. During this step, valve 64 is open, and valves 61, 62, 63, 64, 65, 66, 67, and 68 are closed. The heater 14 is running to heat the PD fluid to, for example, body temperature (37°C), the system pump 43 is running, and the first concentration sensor 8 senses conductivity.

[0125] 9. Add the osmotic agent (here, glucose concentrate) with scale feedback. During this step, valve 61 is open, and valves 62, 63, 64, 65, 66, 67, 68 are closed. The system pump 43 is running, and the second weigh scale 72 measures the weight of the container 9.

[0126] 10. Recirculation and checking of conductivity decrease. The diluted PD concentrate (now the final PD fluid for treatment) is recirculated in a circulation path comprising the fifth fluid line 18, a part of the second fluid line 22, the sixth fluid line 27 and the container 9. During this step, the valve 64 is open and the valves 61, 62, 63, 64, 65, 67, 68 are closed. The heater 14 is running to heat the PD fluid to e.g. body temperature (37°C), the system pump 43 is running and the first concentration sensor 8 senses the conductivity.

[0127] Proceeding:

[0128] 11. Repeat steps 4 to 10 at least once.

[0129] Figure 4 The system 1 in is shown with disposable fluid lines. The pumps are here peristaltic pumps and the system 1 comprises a scale and pinch valves. However, the system can alternatively be a durable and thus sterilizable system. The peristaltic pumps and the scale (or level sensor) can then be replaced by volumetric pumps. The shown system can produce a PD fluid which is finally collected in the container 9. However, for the first fill, the container 9 can contain sterile PD fluid (as there can be no effluent already drained from the patient). Here, the container 9 will be used as a mixing bag for the preparation of the subsequent fill batch. Thus, Figure 4 The system 1 in is used as a mixing system with batched PD fluid production. Instead of disposable bags, internal tanks can be used. The pure water container can be replaced by a water purification device. If disposable bags are used to contain the pure water and the effluent, the water bag can be reused to be used as the effluent bag for the next treatment. If so, the fresh water remaining in the pure water bag after the treatment is completed can be left in the bag and then regenerated together with the effluent during the next treatment. The last drained effluent can be saved and used for water extraction in the initial phase of the next treatment. To perform heat sterilization, the system 1 can be modified to be able to produce a closed hot water path which allows sterilization of the entire system. If extended use of FO membranes 6c is to be employed, FO membranes 6c are included in such a path.

[0130] Reference is now made to , showing an additional alternative embodiment of the system 1 under control of the control unit 40. Figure 5 The system 1 of comprises many components which are the same as described and numbered above. In particular, Figure 5 The system 1 of comprises many components which are the same as described and numbered above. In particular, Figure 5The system 1 includes patient inlet / outlet lines 5, 11, an effluent branch line 5, and a third or outflow fluid line 25 leading to the supply side of the forward osmosis (FO) unit 6. A fourth or drain fluid line 26 is connected between the outlet of the supply side of the FO unit 6 and a drain port 75 and leads to the drain port 75. A second or fresh dialysis fluid line 22 is fluidly connected between the outlet of the draw side of the FO unit 66a and a fresh branch line 11 of the patient inlet / outlet lines 5, 11 and leads to the fresh branch line 11 of the patient inlet / outlet lines 5, 11.

[0131] The osmotic agent source 4c is connected to the fresh dialysis fluid line 22 downstream of the heater 14 via a ninth fluid line 29, which is connected to the source 4c at an osmotic agent connector 3c. The purified water container 7 is connected to the fresh dialysis fluid line 22 upstream of the heater 14 via an eighth fluid line 28 and a water source connector 3d. The effluent container 15 is connected to the outflow fluid line 25 upstream of the FO unit 6 via a fluid line 23 and an effluent container connector 3e. The diluted PD concentrate (e.g., buffer) container 9 is fluidly connected to (i) a sixth or inlet line 27 via a second port 9b and to (ii) a fifth outlet line 18 via a first port 9a.

[0132] Figure 5 One difference of the system 1 is that the PD concentrate (e.g., buffer) container 4a is not directly connected to the extraction side of the FO unit 6, but is connected to the fresh dialysis fluid line 22 via the first fluid line 21 and the first PD concentrate connector 3a. This arrangement allows the flow rate of the first PD concentrate to be directly known from the known speed of the first or dilution pump 41 (providing open loop control).

[0133] Figure 5The system 1 of FIG. 1 includes a plurality of valves (e.g., electrically actuated, electrically open solenoid pinch valves) each under the control of the control unit 40. The valves include a sixth valve 37 positioned along the effluent leg line 5 and allowing or inhibiting flow through the effluent leg line 5. The valves include a fifth valve 35 positioned along the third or effluent fluid line 25 and allowing or inhibiting flow through the third or effluent fluid line 25. The valves include a first valve 32 positioned along the dialysis fluid line 22 and allowing or inhibiting flow through the dialysis fluid line 22. The valves include a seventh valve 30 positioned along the new leg line 11 and allowing or inhibiting flow through the new leg line 11. The valves include an eighth or bypass valve 39 positioned along the bypass flow of fresh dialysis fluid to drain 75 and allowing or inhibiting the bypass flow of fresh dialysis fluid to drain 75. The valves include an exhaust valve 55 positioned along the fourth or exhaust fluid line 26 and allowing or inhibiting flow through the fourth or exhaust fluid line 26 to drain 75. The valves include a ninth or vent valve 38 positioned along the vent flow from the top of the mixing chamber 46 to drain 75 and allowing or inhibiting the vent flow from the top of the mixing chamber 46 to drain 75. The valves include an inlet valve 34 and an outlet valve 33, respectively, allowing or inhibiting the flow of diluted PD concentrate (e.g., buffer) through the inlet line 27 and outlet line 18 into and out of the container 9, respectively. The valves include a PD concentrate (e.g., buffer) valve 45a positioned along the first fluid line 21 from the PD concentrate (e.g., buffer) container 4a to the dialysis fluid line 22 and allowing or inhibiting flow through the first fluid line 21 from the PD concentrate (e.g., buffer) container 4a to the dialysis fluid line 22. The valves also include a valve 45b allowing or inhibiting the flow of filtered forward osmosis water from the draw side of the FO unit 6 to the dialysis fluid line 22.

[0134] Figure 5 The system 1 of FIG. 1 includes a plurality of fluid pumps (e.g., electrically actuated volumetric or piston pumps that are themselves accurate and capable of providing the desired flow rate and volume) each under the control of the control unit 40. The pumps include a first or dilution pump 41 to dilute the PD concentrate (e.g., buffer) from the container 4a with filtered forward osmosis water from the feed side of the FO unit 6. The pumps include a second PD concentrate (e.g., dextrose) pump 42 to accurately meter the concentrate from the container 4c to the dialysis fluid line 22. The pumps include a third or system pump 43 to mix the first diluted concentrate (e.g., buffer) with the second concentrate (e.g., dextrose). The pumps also include a fourth or effluent pump 44 to pump patient effluent to the effluent container 15 and to pump patient effluent from the effluent container 15.

[0135] Figure 5 The system 1 of FIG. 1 includes a mixing chamber 46 for mixing the final PD fluid having a prescribed concentration of two or more PD concentrate fluids (e.g., a buffer and dextrose). In one embodiment, the mixing chamber 46 is small in size and does not hold the full volume for filling, and can instead be an enlargement of the second fluid line 22. The mixing chamber 46 also serves as a gas trap that allows gas (e.g., air) to migrate out of the final PD fluid and into the top of the gas trap. In the illustrated embodiment, the mixing chamber 46 is operated with level sensors 46a and 46b that output to the control unit 40, where the control unit 40 uses the signals from the sensors 46a and 46b to operate the system pump 43 so as to maintain a desired level of the final PD fluid between the sensors.

[0136] Figure 5 Other sensors in the system 1 of FIG. 1 that each output to the control unit include an inlet pressure sensor 53 whose output is used to control negative patient pumping pressure to a safe level (e.g., -.10 bar (-1.5 psig) or less) at the end of the FO session, e.g., via the effluent pump 44, and to sense and control the supply side pressure. Other sensors include a first concentration sensor 8 that senses the conductivity of the first PD concentrate (e.g., a buffer) that is being diluted, the output of which can be used to control the first or dilution pump 41 to achieve a desired conductivity at the concentration sensor 8. Other sensors include a temperature sensor 51 whose output can be used to control the power input to the heater 14 to heat the final PD fluid to a desired body temperature (e.g., 37°C). Other sensors include a second concentration sensor 13 that senses the conductivity of the final PD fluid (e.g., including the buffer and dextrose concentrate), the output of which can be used to control the second PD concentrate (e.g., dextrose) pump 42 and the first or dilution pump 43 to achieve a desired final PD fluid conductivity at the concentration sensor 13. Other sensors also include an outlet pressure sensor 52 whose output is used to control positive patient pumping pressure to a safe level (e.g., 0.21 bar (3.0 psig) or less), e.g., via the system pump 43.

[0137] While Figure 5The system 1 of FIG. 1 is shown with a pure water container 7, but it is possible that the container 7 can not be needed, which is desirable because the patient does not have to install a large water container for each treatment. To eliminate the pure water container 7, the amount of water needed for the entire treatment is filtered from the patient's effluent, and then it is assumed that the PD concentrate from the container 4a can be diluted as needed to form the final PD fluid. To have enough effluent, it is contemplated that the control unit 40 holds patient effluent from a previous treatment to use as a feed solution for the current treatment. Thus, the effluent container 15 can be a reusable container that is large enough to hold the effluent needed for the treatment, e.g., a volume of about 6 to 8 liters. It is also contemplated that the control unit 40 begins FO filtering of the effluent and dilution of the PD concentrate (e.g., buffer) from the container 4a before the treatment begins. Here, the diluted PD concentrate (e.g., buffer) container 9 is also reusable, and it is sized to hold a large amount of diluted PD concentrate before the treatment begins, e.g., a volume of about 6 to 8 liters. In addition, the control unit 40 can perform the FO session using a slow or low flow rate, which is beneficial because a larger percentage of the filtered water can be extracted.

[0138] The patient is likely to start the full treatment with the last fill volume from a previous treatment or mid-day exchange. The control unit 40 has the effluent pulled into the effluent container 15 (which is now likely empty after the slow FO filtration) at the beginning of the treatment to be stored with the newly generated effluent produced during the current treatment. Notably, the effluent container 15 is not emptied at the end of the treatment, but rather it is used to store the effluent from the current treatment and the effluent from the next treatment. Figure 5 In the system 1 of FIG. 1, water extraction can also be performed during the patient dwell phase of the current treatment in addition to the daily water extraction.

[0139] Figure 5 Another difference of the system 1 of FIG. 1 is that one or more ultraviolet ("UV") lamps 58a, 58b are provided, which are positioned at the effluent container 15 (which can be provided with any version of the system 1 discussed herein) or at the inlet of the effluent container 15. The one or more UV lamps 58a, 58b are positioned to irradiate the effluent and begin disinfecting the effluent, thereby mitigating the pathogen load on the FO unit 6. The UV lamps 58a, 58b can be provided with any version of the system 1 discussed herein.

[0140] To dilute the first concentrate (e.g., buffer) from the container 4a, the control unit 40 causes the first concentrate to be introduced into the second fluid line 22 while valves 45a and 45b are open, and valves 32, 33, and 34 are closed. Thus, the concentrate is forced into the FO unit 6 for dilution, after which the concentration or conductivity of the diluted concentrate is acquired via the sensor 8, and the diluted PD concentrate fluid is stored in the diluted PD concentrate container 9. If desired, the diluted PD concentrate can be recirculated through the sensor 8 by opening valves 33 and 34 and running the dilution pump 41. When the first concentrate is introduced into the FO unit 6 via valve 45b, as described above, water extraction is in an active state, and then the dilution pump 41 can be run open loop, knowing the set speed of the dilution pump.

[0141] As described above, in various embodiments of the system 1, Figure 5 In other embodiments, FO filtration can be performed in the FO unit 6 between treatments and during any one or more dwell periods during a treatment. In yet other embodiments, no FO filtration is performed in the FO unit 6 between treatments, but all FO filtration is performed at the beginning of a treatment and during the patient’s dwell. In cases where more filtration occurs between treatments requiring larger containers, the selected embodiment dictates the size of the effluent container 15 and the diluted PD concentrate container 9.

[0142] For any version of the system 1, including versions of the system 1, Figure 4 The flow rates produced by the effluent pump 44 and the dilution pump 41 depend on the available effluent volume and the time available for water extraction for any version of the system 1, including versions of the system 1. Lower flow rates for these pumps improve the extraction efficiency discussed herein. The flow rates of the pumps 41 and 44 also depend on the size of the FO unit 6. Larger surface areas for this unit improve efficiency, which can allow for higher flow rates. Overall, what determines efficiency is the combination of the effluent flow rate, the concentrate flow rate, and the membrane surface area.

[0143] In various examples, two liters of effluent over a two hour dwell period (providing approximately 110 minutes of time available for extraction) yields a flow rate of 18 ml / min, which is considered slow. Three liters of effluent over a one hour dwell period can yield a flow rate of 60 ml / min, which is considered fast. If dwell time and daylight hours are available, this can mean, for example, that 12 liters of effluent can be processed over a 6 hour dwell at night and 8 hours during the day (14 hours total, which yields an effluent flow rate of 14 ml / min, which is considered very slow and efficient). The very low effluent flow rate of 14 ml / min can be used to increase efficiency or to reduce the membrane surface area of FO unit 6 while maintaining efficiency. The low flow rate also means that extraction can be performed effectively only during daylight hours and not during the entire treatment dwell. Another alternative is to increase the membrane surface area of FO unit 6 to allow for a higher effluent flow rate and maintain efficiency.

[0144] The flow rate of system pump 43 and second PD concentrate pump 42 can be higher than the FO session flow rate, for example, approximately 100 to 250 ml / min, because the efficiency of FO unit 6 is not an issue and because it is desirable to fill the patient as quickly as safely possible to reduce treatment time and to allow a larger percentage of the treatment time to be used for patient dwell, where the patient is being treated.

[0145] It is contemplated that a pressure gradient is maintained between the feed side and the draw side of FO unit 6, with the feed side pressure being greater than the draw side pressure. Doing so increases the water extraction efficiency of FO unit 6. The pressure gradient or ΔΡ can be anywhere from zero bar to four bar (58 psig) or higher, depending on the manufacturer of the FO unit. Figure 1 One way of creating a higher feed side pressure is shown, which is to make line 26 operatively communicate with variable restrictor 54 under the control of control unit 40. Control unit 40 causes variable restrictor 54 to partially obstruct line 26, thereby creating increased back pressure in the feed side of FO unit 6. Alternatively or additionally, the pressure gradient can be induced by reducing the pressure on the draw side of FO unit 6. It is contemplated that the draw side pressure is reduced hydrostatically by configuring system 1 such that diluted PD concentrate container 9 is at a lower elevation relative to FO unit 6.

[0146] Extraction efficiency is not dependent on the pressure output of system pump 43. Rather, the pressure output of system pump 43 (measured by outlet pressure sensor 52) is controlled such that the final PD fluid is delivered safely to the patient (e.g., 0.21 bar (3.0 psig) or less).

[0147] Alternatively or additionally, the extraction efficiency can be increased by heating or increasing the temperature of the FO unit 6. For example, if it is desired to have a higher FO unit 6 temperature, an additional or alternative heater (e.g., a pre-heater (not shown)) can be placed along the effluent fluid line 25 that heats or increases the temperature of the effluent, which in turn heats or increases the temperature of the FO unit 6 and FO membrane 6c. For example, the increased effluent temperature can be anywhere from slightly above ambient temperature to 50°C or higher, depending on the requirements of the FO unit. The temperature to which the effluent is heated is chosen so that the FO unit 6 is in turn heated to the desired level, and also so that the final PD fluid delivered to the patient can be set to about body temperature or 37°C. It can be found that the FO unit 6 acts as a heat sink, such that even if the effluent is heated to 50°C, the diluted concentrate exiting the FO unit 6 is below 50°C, and thus still requires heating via the heater 14 downstream. Fouling in the effluent fluid line 25 is also a consideration in determining the temperature to which the effluent is heated, as higher temperatures can increase fouling. The reason for the increase in extraction efficiency that occurs by heating the FO unit 6 can be related to an increase in flux across the FO membrane 6c.

[0148] Thus, it is expressly contemplated that any version of the system 1 discussed herein manipulates, selects or sets any one or more of the membrane surface area, feed side and draw side flow rates, pressure gradient ΔP or transmembrane pressure across the membrane and / or increased FO membrane temperature to achieve a desired exchange efficiency. These variables are balanced against cost and ease of use to produce an overall desirable system 1.

[0149] It is also expressly contemplated that any version of the system 1 discussed herein replaces the conductivity sensor 8 with two weigh scales (or additionally provide weigh scales), one measuring the weight of the diluted PD concentrate container 9 and the other measuring the weight of the first concentrate in the first concentrate container 4a. Here, the control unit 40 knows the concentration of the first concentrate in the first concentrate container 4a, so that the concentration / conductivity of the diluted first PD concentrate can be determined based on that knowledge and the weigh scale measurements output to the control unit 40. Weigh scales can be beneficial if, for example, conductivity is found to be difficult to measure. The weigh scales can be configured and arranged the same as the weigh scales 71, 72 and 73 shown. Figure 5 The weigh scales 71, 72 and 73 are configured and arranged the same as shown.

[0150] In an alternative embodiment, if the dilution pump 41 is of the accurate type, e.g. a membrane pump or a piston pump, then it can be possible to only need a single weighing scale provided with the diluted PD concentrate container 9. That is, the control unit 40 knows how much first PD concentrate is withdrawn from the first concentrate container 4a based on the known number of strokes performed by the accurate dilution pump 41. What is not known is how much filtered water dilutes the first PD concentrate through the membrane of the FO unit 6. However, the weighing scale provided with the diluted PD concentrate container 9 provides this information. Thus, the control unit 40 can again determine the concentration / conductivity of the diluted first PD concentrate given the known concentration of the first PD concentrate.

[0151] Figure 6 It is shown that an optional additional PD concentrate bag 4b can be connected to an additional PD concentrate connector 3b via an optional bag connector. It is also explicitly contemplated that any version of the system 1 discussed herein uses separate containers or bags 4a and 4b to separate the single concentrate into components that can have a higher concentration, e.g. a concentrated NaCl component solution. The concentrated component solution makes the draw solution more concentrated. In the example where NaCl is the concentrated component solution, the draw solution can become about twice as concentrated (e.g. about 11 Osm / l compared to 5.4 Osm / l). The advantage of the separated concentrated component solution is that less total fluid volume is delivered to the patient. The concentrated component solution is dosed separately from the dosing of the remaining portion of the total concentrate from the other container 4a, 4b.

[0152] Providing a concentrated NaCl solution also allows for sodium profiling, where NaCl is dosed according to the physiological make-up or needs of the patient. The dosage of NaCl can be varied during the treatment according to a profile under the control of the control unit 40. The variation of the sodium profile (e.g. more at the beginning of the treatment and less at the end of the treatment) is set to provide a treatment benefit to the patient.

[0153] Figure 6 (and the below discussed Figure 6 ) shows an optional line 47 and valve 48 under the control of the control unit 40 that can be provided for any version of the system 1 described herein. The optional line 47 and valve 48 can be considered a bypass valve. The optional line 47 and valve 48 allow any fluid that is sent to the drain 75 to instead be transferred to the effluent container 15 for reprocessing at the FO unit 6. For example, the volume of mixed fluid that has not yet had the correct concentration that would normally be sent to the drain during the in-line mixing can here instead be pumped to the effluent container 15 with the valve 48 open and the valves 30, 38 and 39 closed for later extraction at the FO unit 6.

[0154] Another option for any version of system 1 described herein is that the diluted PD concentrate container 9 is initially provided with purified or sterile water so that the purified water container 7 can be removed while still providing a source of water. The diluted PD concentrate container 9 is only partially filled with purified or sterile water, for example 10% to 40%, allowing the diluted first PD concentrate exiting the draw side of the FO unit 6 to mix with water to further dilute.

[0155] Reference is now made to Figure 6 , showing an alternative CFPD version of system 1 under control of control unit 40. Figure 6 includes many of the same components as the previously described versions of system 1, which are identically numbered and include all of the structure, function, and alternatives discussed above for the identically numbered components. In Figure 6 , the effluent container 15 includes an effluent container connector 3e, which here is an inlet connector, and an additional effluent container connector 3f that allows effluent to flow into and out of the effluent container 15. An additional drain pump 49 under control of control unit 40 allows effluent from line 5 to be pumped to the effluent container 15, while the effluent pump 44 independently pumps effluent into the feed side of the FO unit 6. The dilution pump 41 can pump the first PD concentrate from container 4a into the draw side of the FO unit 6 at the same or different times. The second PD concentrate pump 42, system pump 43, and concentrate pump 81 operate as described below to add and mix the second PD concentrate to form the final PD solution.

[0156] In particular, in one embodiment, Figure 6The control unit 40 of the system 1 in FIG. 1 is programmed to operate in a CFPD mode in which effluent is slowly removed from the patient P to the effluent container 15 via the drain pump 49 and valve 37. At the same time, the control unit 40 fills the patient P at the same rate (or can be at a different rate than the drain flow rate, e.g., to account for ultrafiltration) via the system pump 43 and valve 30. If the fill flow rate and the drain flow rate are the same, then there is no net volume change in the patient other than the volume of fluid absorbed with ultrafiltration ("UF"). The control unit 40 causes the effluent pump 44 to remove effluent from the effluent container 15 to the feed side of the FO unit 6 at a desired flow rate for FO extraction, where the portion of the effluent not extracted is passed from the FO unit to the drain 75 via valve 55. At the same or different time, the control unit 40 causes the dilution pump 41 to pump the first PD concentrate through the draw side of the FO unit 6 via valves 45b and 80 at a desired flow rate to pass the desired amount of diluted PD concentrate to the container 9. At the same or different time, the control unit 40 causes the first PD concentrate pump 81 to remove the diluted first PD concentrate from the diluted PD concentrate container 9 and pass it to the second fluid line 22. The PD concentrate pump 81 can be controlled so that the appropriate conductivity is reached at the sensor 13 (where in one embodiment, the first PD concentrate pump 41 and the effluent pump 44 are controlled to follow the flow rate of the PD concentrate system pump 43). The control unit 40 also causes the system pump 43 to pull the desired amount of purified water from the purified water container 7 via valve 82. The control unit 40 also causes the second PD concentrate pump 42 and the system pump 43 to operate at a fixed flow rate, which in one embodiment is according to a flow ratio pump 43 / pump 42 determined at an initial phase when the fluid produced is not yet the correct PD fluid (at which initial phase, the fluid can be directed to the effluent container 15 via valve 48 so that no liquid to be drained is lost). The system pump 43 pumps the final PD fluid to the patient P via valve 30.

[0157] Alternatively or additionally, Figure 6 The control unit 40 of the system 1 in FIG. 1 can be programmed to operate a batch APD treatment. In Figure 5 to Figure 7 In FIG. 1, with all valves closed except valves 45b, 55, and 80, the system 1 can perform a dwell phase in which the final PD fluid dwells within the peritoneal cavity of the patient P for a specified period of time. The control unit 40 can simultaneously operate the effluent pump 44 and the dilution pump 41 to perform FO, producing new diluted first PD concentrate and passing it to the diluted PD concentrate container 9.

[0158] In CFPD or APD mode, control unit 40 can be programmed to run the FO session simultaneously and to empty patient P. Here, in addition to valves 45b, 55 and 80 being open and pumps 44 and 41 being run, valve 37 is also open and drain pump 49 is run to pull outflow from patient P to outflow container 15. Drain valve 55 is open to allow the flow of drain fluid to drain 75.

[0159] In CFPD or APD mode, control unit 40 can be programmed to run the FO session simultaneously and to fill patient P with fresh, heated final PD fluid. Here, in addition to valves 45b, 55 and 80 being open (optionally, valve 37 is open) and pumps 44 and 41 being run, valves 30 and 82 (water valve) are also open (valve 32 is closed) and pumps 81, 42 and 43 are run. Conversely, if the diluted first PD concentrate is over-diluted, or if the diluted PD concentrate container 9 is empty, valve 32 can be opened to allow pure first PD concentrate from container 4a to be transferred to second fluid line 22 via dilution pump 41.

[0160] Figure 5 CFPD (and APD) system 1 is enabled to be as water-efficient as possible, where the outflow flow rate using outflow pump 44 can be lower than the patient drain flow rate using drain pump 49. Control unit 40 is able to control outflow pump 44 to pump to FO unit 6 to enable the FO session to be independent of the drain flow rate pumped via drain pump 49. In one example, a full drain is performed using drain pump 49 at 200 ml / min, while outflow pump 44 provides a low and efficient outflow volume of, for example, 30 ml / min.

[0161] It should also be appreciated that the placement of drain pump 49 enables system 1 to perform a full drain on the patient, where all outflow can be moved to outflow container 15 via pump 49, and then use the outflow to run the FO session.

[0162] Figure 6 Any version of system 1 discussed herein (e.g., batch system of Figure 5 to Figure 7 and continuous system of Figure 6 ) can be enabled by having a flow path along Figure 7One or more sterilizing grade filters 69a, 69b can be placed in line with the patient fluid line 11 to operate in the system 1. The sterilizing grade filter(s) 69a, 69b can have a pore size of about 0.2 microns (it can be larger or smaller), which places the final PD fluid under sterile conditions suitable for delivery to the patient P. For example, the filter(s) 69a, 69b can allow the water in the purified water container 7 to be maintained at a purified level rather than a sterilized level. Two sterilizing grade filters 69a and 69b provide redundancy in the event one of the filters fails. Also, the sterilizing grade filters 69a, 69b can be provided with any embodiment of the system 1 discussed herein.

[0163] Figure 7 It is also shown that any version of the system 1 discussed herein can include a coarse filter or pre-filter 70 positioned along the effluent line 5. In the system 1 discussed below in Figure 7 , or any other batch version of the system 1, the coarse filter 70 can be positioned along the effluent branch line 5, while sterilizing grade filters 69a and 69b are positioned along the new branch line 11 leading to the common effluent / fresh patient fluid line 5 / 11. For example, the coarse filter 70 can have a larger pore size selected to remove fibrin or other patient material from reaching the FO unit 6. The coarse filter 70 can also reduce fouling at the FO unit 6. Also, the coarse filter 70 can be provided with any embodiment of the system 1 discussed herein.

[0164] Reference is now made to Figure 7 , which shows an alternative online batch version of the system 1. Figure 7 includes many of the same components as the previously described systems, which are identically numbered and include all of the structure, function, and alternatives discussed above for the identically numbered components. In ​ , a dedicated first PD concentrate pump 57 is provided under the control of the control unit 40, which is positioned along a line branching from the first fluid line 21 to the draw side of the FO unit 6. The dedicated first PD concentrate pump 57 enables the first PD concentrate (e.g., buffer) to be pulled from the first PD concentrate container 4a and pushed through the FO unit 6 to the diluted PD concentrate container 9 via the line 27, while the dilution pump 41 pulls the diluted first PD concentrate container from the diluted PD concentrate container 9 via the line 27.

[0165] Since the timing of the FO phase is an important determinant, it may be desirable to begin the FO phase as soon as possible after the drainage is completed. The additional first PD concentrate pump 57 can be an accurate pump (e.g., a membrane pump or a piston pump) so that the FO phase can be run in parallel with the mixing phase. When there is no effluent, the dilution pump 41 delivers the diluted first concentrate to be added to glucose and possibly purified water to make the desired final PD fluid for delivery to the patient P. Simultaneously, the additional first PD concentrate pump 57 performs the FO.

[0166] Recirculation using the dilution pump 41 can be performed as described herein and can begin immediately after the patient fill is complete. ​ In the embodiment of the present invention, the diluted first PD concentrate is supplied to the diluted PD concentrate container 9 from line 27, wherein line 27 does not include a concentration or conductivity sensor 8. The reason for this is to avoid disturbing the concentration of the diluted first PD fluid leaving the diluted PD concentrate container 9 via line 18, which passes through the concentration or conductivity sensor 8 for checking and feeding back to the control unit 40. Alternatively, the concentration or conductivity sensor 8 can be moved to line 27, assuming that the diluted concentrate in the diluted PD concentrate container 9 is homogeneous at the beginning of filling. The new diluted first PD concentrate can then be compared with the diluted first PD concentrate of the previous period.

[0167] While the invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but on the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the purview of the appended claims.

Claims

1. A system (1) for generating a fluid for peritoneal dialysis (PD), the system (1) comprising: A fluid path (2) comprising: two or more PD concentrate connectors (3a, 3b, 3c), each connector configured to connect to a source of PD concentrate fluid (4a, 4b, 4c); and an inlet connector (5a, 11a) configured to connect to a fluid line (5, 11) arranged to convey outflow fluid from a patient; A forward osmosis (FO) unit (6) comprising an extraction side (6a) and a supply side (6b) separated by an FO membrane (6c), the FO unit (6) being fluidically connected to the fluid path (2), wherein the FO unit (6) is configured to receive one or more PD concentrated fluids (4a, 4b) at the extraction side (6a) and receive an effluent at the supply side (6b), wherein water is transported from the effluent to the one or more PD concentrated fluids through the FO membrane (6c) by means of an osmotic pressure gradient between the extraction side (6a) and the supply side (6b), thereby diluting the one or more PD concentrated fluids into a diluted PD concentrated fluid; wherein the fluid path (2) comprises a circulation fluid path (16) for circulating the diluted PD concentrated fluid; a concentration sensor (8) configured to sense the concentration of the diluted PD concentrated fluid; and The control device (10) is configured to: controlling the flow rate of the outflow fluid into the supply side (6b), and controlling the flow rate of the one or more PD concentrated fluids (4a, 4b) into the extraction side (6a) to produce the diluted PD concentrated fluid based on the desired composition of the final PD fluid, the concentration of the one or more PD concentrated fluids, the amount of available effluent, and the available time of the FO period, circulate the diluted PD concentrated fluid in the circulation fluid path (16) until a mixing standard of the diluted PD concentrated fluid is satisfied based on the concentration sensed by the concentration sensor (8); and The flow rate of the second concentrate or the third concentrate (4c) into the diluted PD concentrate fluid is controlled to form the final PD fluid.

2. The system (1) according to claim 1, wherein The control device (10) is configured to perform (i) control the flow rate of the outflow fluid into the supply side (6b) before processing, and (ii) control the flow rate of the one or more PD concentrated fluids (4a, 4b) to produce the diluted PD concentrated fluid.

3. The system (1) according to claim 1 or 2, wherein: The control device (10) includes a first pump (41) configured to pump the one or more PD concentrated fluids into the extraction side (6a).

4. System (1) according to any one of the preceding claims, wherein The control device (10) is configured to cause, prior to treatment, the delivery of effluent fluid from the patient for storage.

5. The system (1) according to claim 3 or 4, comprising a second pump (42), wherein the second pump (42) is configured to pump the second concentrate or the third concentrate, wherein the second concentrate or the third concentrate comprises an osmotic agent.

6. The system (1) according to any one of the preceding claims, comprising a fluid path (2), the fluid path (2) comprising a water source connector (3d) downstream of the FO unit (6), the water source connector (3d) being configured to be connected to a source of pure water (7), and wherein, The control device (10) is configured to supply purified water from the purified water source (7) to the diluted PD concentrated fluid to achieve a specified composition of the final PD fluid.

7. The system (1) according to claim 6, the system (1) being configured to sense the concentration of the final PD fluid, wherein The control device (10) is configured to control the flow rate of the diluted one or more PD concentrated fluids (4a, 4b) and the second concentrated liquid or the third concentrated liquid (4c) to achieve a prescribed composition of the final PD fluid based on the sensed concentration of the final PD fluid.

8. The system (1) according to any one of the preceding claims, comprising a system pump (43) configured to pump the flow rate of the final PD fluid.

9. The system (1) according to any one of the preceding claims, comprising a diluted PD concentrate container (9) fluidically connected or connectable to the fluid path (2), wherein The diluted PD concentrate container (9) is arranged to receive the diluted PD concentrated fluid, and wherein the diluted PD concentrate container (9) is optionally initially partially filled with purified water.

10. The system (1) according to any one of the preceding claims, comprising an effluent pump (44) configured to pump a flow rate of effluent fluid into the supply side (6b).

11. The system (1) according to any one of the preceding claims, comprising a heater (14) configured to heat the fluid in the fluid path (2).

12. The system (1) according to any one of the preceding claims, comprising an effluent container (15) fluidically connected to the fluid path (2) and the inlet connector (5a, 23a), wherein The effluent container (15) is arranged to collect effluent fluid received from the patient before the effluent fluid is input into the supply side (6b).

13. System (1) according to any one of the preceding claims, wherein The one or more PD concentrated fluids (4a, 4b) include a fluid comprising one or more of lactic acid, acetic acid, citric acid, bicarbonate, NaCl, MgCl2, CaCl2, and KCl.

14. System (1) according to any one of the preceding claims, wherein One of the PD concentrate fluids (4a, 4b) includes a higher concentration of a component solution, such as NaCl, than in a fully mixed version of the PD concentrate, and the other of the PD concentrate fluids (4a, 4b) includes the remaining concentrate.

15. The system (1) according to any one of the preceding claims, being a continuous flow peritoneal dialysis (CFPD) system and comprising a drain pump (49) positioned and arranged to pump effluent from the patient to a position for delivery to the supply side (6b) of the FO unit (6).

16. System (1) according to claim 9 and optionally according to any one of claims 10 to 15, wherein The control device (10) includes a first pump (41) and a second PD concentrate pump (57), wherein the first pump (41) is configured to pump the diluted one or more PD concentrated fluids from the diluted PD concentrate container (9), and the second PD concentrate pump (57) is configured to pump the one or more PD concentrated fluids into the extraction side (6a) of the FO unit (6).

17. The system (1) according to any one of the preceding claims, comprising a line (47) and a valve (48) positioned and arranged to enable initially but not fully diluted PD concentrated fluid to be redirected for delivery to the supply side (6b) of the FO unit (6).

18. The system (1) according to any one of the preceding claims, comprising a device (54) configured and arranged to generate a higher pressure on the supply side (6b) of the FO unit (6) than on the extraction side (6a).

19. A method for producing fluid for peritoneal dialysis (PD) in a system (1), the system (1) comprising a forward osmosis (FO) unit (6), the FO unit (6) comprising an extraction side (6a) and a supply side (6b) separated by an FO membrane (6c), the FO unit (6) being configured to receive one or more PD concentrated fluids (4a, 4b) at the extraction side (6a) and receive effluent fluid from a PD patient at the supply side (6b), to transfer water from the effluent to the one or more PD concentrated fluids through the FO membrane (6c) by means of an osmotic pressure gradient between the extraction side (6a) and the supply side (6b), thereby diluting the one or more PD concentrated fluids (4a, 4b) into diluted PD concentrated fluids, the method comprising: controlling (S2) the flow rate of the outflow fluid into the supply side (6b) of the FO unit (6); as well as controlling (S3) the flow rate of the one or more PD concentrated fluids (4a, 4b) into the extraction side (6a) to produce the diluted PD concentrated fluid based on the desired composition of the final PD fluid, the concentration of the one or more PD concentrated fluids, the amount of available effluent, and the time available for the FO phase; sensing (S4) the concentration of the diluted PD concentrated fluid; circulate (S6) the diluted PD concentrated fluid in a circulation fluid path (16) based on the sensed concentration of the diluted PD concentrated fluid until a mixing standard of the diluted PD concentrated fluid is met; as well as The flow rate of the second concentrate or the third concentrate (4c) into the diluted PD concentrate fluid is controlled (S7) to form the final PD fluid.

20. The method according to claim 19, wherein Controlling the flow rate of the effluent and the flow rate of the one or more PD concentrated fluids (4a, 4b) is performed before treatment, and controlling the flow rate of the second concentrate or the third concentrate is performed during treatment.

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