Patent Description:
It has become increasingly common to provide medical care for patients at the patients' homes. For patients suffering from renal failure, home therapies with peritoneal dialysis (PD) or haemodialysis (HD) are options that enable the patients to treat themselves at home and reduce the amount of medical centre visits.

Such dialysis treatments require dialysis fluids that typically have been provided ready to use in sealed, sterilized containers and delivered to the patient's home in <NUM>-<NUM> litres bags. A PD treatment requires between <NUM> and <NUM> litres of dialysis fluid per day, <NUM> days a week, <NUM> days a year for each patient. Considering the distribution effort to provide each patient with the containers and that many patients have difficulties to handle and store the containers, mixing or compounding of dialysis fluid at the point of care, e.g. at the patient's home, has been suggested. Concentrates are then mixed with water to become dialysis fluid at the point of care. The concentrates have to be provided to the point of care, but in a much smaller amount than the ready to use dialysis fluids. The concentrates are generally highly concentrated, <NUM>-40x compared to ready to use fluids.

Automated PD normally uses a cycler for pumping the dialysis fluid to a patient and to remove used dialysis fluid from the patient. This is done via a cassette connected to lines leading to the dialysis fluid bags, the patient and the drain.

One of the major side-effects of PD is the risk for peritonitis which can have severe consequences for the patient and in the end result in that the patient cannot use PD treatment anymore. The risk for peritonitis is strongly connected to touch contamination during connection to peritoneum and the presence of microorganisms in the inflowing dialysis fluid. Patients are trained to perform the connections aseptically and with special care to avoid contamination.

Thus, in order to perform PD treatment successfully it is of vital importance to avoid all risks of contamination and risk of introducing microorganisms in the system, potentially reaching peritoneum, during treatment and preparation for treatment.

In the preparation of the dialysis fluid, and in line with above, water of a high purity level should be used. From <CIT> it is known to purify water, mix the purified water with concentrates to prepare a dialysis solution and use the dialysis solution in haemodialysis treatment. The membrane of the dialyzer serves as an additional barrier for any contaminants. According to <CIT>, bacteria will over time proliferate on the inner surfaces of the fluid circuits. To reduce such contamination, heat disinfection of the fluid circuit, including the extracorporeal lines, is performed. Water is heated to a high temperature and is circulated in the fluid circuit. As the fluid circuit includes the dialysis solution preparation with a chemical mixing tank, the water treatment and the extracorporeal dialysis modules, the amount of heated water and power needed to disinfect the fluid circuit is large and the heating process is time consuming.

<CIT> discloses a water treatment device that provides water treated by means of a reverse osmosis filter. The treated water is transported to a haemodialysis apparatus for further mixing with additional substances. Heat disinfection is used to disinfect portions of the fluid path of the water treatment device.

A further water treatment system is known from <CIT>.

Some applications, e.g. PD, demand a very high purity of the dialysis solution. The purity of the dialysis solution has to be of such purity that it is suitable to be infused into the peritoneum.

It is an objective of the disclosure to provide a point of use system and method that enable microbiological control of the production of purified water to be used for providing dialysis fluid. It is a further objective to provide a cost efficient way of producing the purified water. It is a still further objective to provide a cost efficient way of producing the dialysis fluid. Another objective is to provide a point of use system and method that enable production of purified water that is suitable to be used in producing PD fluid. It is a further objective to provide a point of use system and method that enable production of the PD fluid.

These objectives and others are at least partly achieved by the independent claims, and by the embodiments according to the dependent claims.

According to a first aspect, the disclosure relates to a system comprising an integrated water purifying apparatus. The water purifying apparatus comprises a pre-filter circuit connected to a water inlet for receiving water from a water source, a particle filter and an activated carbon filter arranged to filter water received via the water inlet to produce pre-treated water. The water purifying apparatus further comprises a fluid circuit arranged to receive pre-treated water from the pre-filter circuit, the fluid circuit includes an RO-pump and a Reverse Osmosis, RO, device. The water purifying apparatus is further arranged to pump pre-treated water through the RO device using the RO-pump, to produce purified water, and output the purified water through the purified water outlet connector. The fluid circuit further includes a heating device arranged to heat purified water from the RO device to a temperature above <NUM>. The water purifying apparatus is further arranged to heat disinfect the fluid circuit using the heated purified water. The system further comprises a line set connected to the purified water outlet connector at a water line connector of the line set. The line set includes at least one sterile sterilizing grade filter arranged to filter the purified water into sterile purified water.

The system provides microbiological control of the production of fluids for a dialysis treatment, especially dialysis fluid for PD. "Microbiological" and "microbial" are in this disclosure regarded as synonyms. As the water purifying apparatus can heat sterilize its fluid circuit, bacterial growth in the fluid circuit can be prevented. The at least one sterile sterilizing grade filter makes sure that the water from the water purifying apparatus is sterile. Thus, the system ensure continuous production of purified water with a high purity level, thus with no bacteria and a very low amount, i.e. concentration, of endotoxins.

According to some embodiments, the line set is a reusable line set. Thus, the line set can be used more than once. Between treatments, the line set should be rinsed and disinfected.

According to some embodiments, the fluid circuit is arranged to produce purified water with an amount of bacteria that is less than <NUM> Colony-Forming Units/mL and an amount of bacterial endotoxins that is less than <NUM> Endotoxin Units/mL. Thus, the water purifying apparatus is capable of producing purified water with a (microbial) purity level as of water for dialysis.

According to some embodiments, the at least one sterile sterilizing grade filter is arranged to filter the purified water into sterile purified water with an amount of bacteria that is zero Colony-Forming Units/mL and an amount of bacterial endotoxins that is less than <NUM> Endotoxin Units/mL. Thus, the at least one sterile sterilizing grade filter ensures sterility of the produced purified water.

According to some embodiments, the fluid circuit includes an Electro Deionization unit, EDI unit, arranged to further treat the purified water from the RO device and output further purified water, wherein the fluid circuit is arranged to output the purified water from the EDI unit through the water outlet connector. The EDI unit is capable of purifying the water from the RO device to have a conductivity level of less than <NUM>/cm at 25ºC, and less than <NUM>/cm at 20ºC.

According to some embodiments, the line set comprises a drain line connected at a drain line connector of the drain line to a drain connector of the water purifying apparatus, the water purifying apparatus further comprises a first drain path connected to the drain connector for transporting drain fluid received from the drain line of the line set to a drain. Thus, used fluid can be transported to a drain via the line set.

According to some embodiments, the water purifying apparatus further is arranged to heat disinfect the drain connector and the water outlet connector of the water purifying apparatus using the heated purified water. Thus, these connectors that may be exposed to contamination from outside of the water purifying apparatus can be heat disinfected whereby the microbiological control of the system is improved.

According to some embodiments, the water purifying apparatus comprises a control unit programmed to periodically instruct the water purifying apparatus to heat the purified water flowing in the fluid circuit by means of the heating device to a temperature above <NUM> and to control heat disinfection of the fluid circuit using the heated water such that a certain disinfection criterion is met. For example, the disinfection criterion may include meeting a certain time and temperature of the heat disinfection determined for example according to an A0 concept, as known in the art.

According to some embodiments, the control unit is programmed to instruct the water purifying apparatus to heat water flowing in the fluid circuit by means of the heating device and to output the heated water through the purified water outlet connector to the line set for heat disinfection of the line set. The water may also here be heated to a temperature above <NUM>ºC, such as between <NUM>ºC and <NUM>ºC.

According to some embodiments, the system comprises at least one concentrate source, a cycler including a cycler control unit, a pump actuator arranged to be controlled by the control unit, wherein the line set is operable with the cycler and further comprises a pumping cassette having a pump chamber configured to be actuated by the pump actuator and a mixing container in fluid communication with the pumping cassette. Further, the cycler control unit comprises instructions for mixing the purified water and the at least one concentrate, the instructions include to cause the pump actuator to operate the pump chamber to pump a first amount of the purified water to the mixing container and cause the pump actuator to operate the pump chamber to pump a prescribed amount of the at least one concentrate from the at least one concentrate source to the mixing container. Optionally, the instructions include to also cause the pump actuator to operate the pump chamber to pump a second amount of the purified water to the mixing container. Thus, the system may be capable of preparing a dialysis fluid such as a PD fluid from the purified water and the concentrate(s). The prepared dialysis fluid will thus be suitable for PD if the concentrates are sterile and the purified water is sterile and non-pyrogenic.

According to some embodiments, the cycler control unit comprises instructions for performing a heat disinfection of the line set. The instructions include to cause the pump actuator to circulate hot water in the line set. The hot water is received from the water purifying apparatus. Thus, the line set may be heat disinfected such that it can be reused. In an example embodiment, the instructions include to cause the pump actuator to pull (i) hot water from the mixing container into the pump chamber, cause (ii) the pump actuator to operate the pump chamber to push the hot water into the mixing container, and repeat (i) and (ii) at least one time.

According to a second aspect, the disclosure relates to a method for producing microbiologically controlled fluid with a system. The system comprises a water purifying apparatus with a heat disinfected fluid circuit arranged for producing purified water, and a line set connected to a water outlet connector of the water purifying apparatus for transporting the purified water to a point of use. The method comprises treating water from a water source with a Reverse Osmosis unit, RO unit, of the fluid circuit to produce purified water with an amount of bacteria that is less than <NUM> Colony-Forming Units/mL and an amount of bacterial endotoxins that is less than <NUM> Endotoxin Units/mL. The method further comprises directing the purified water through the purified water outlet connector and the thereto connected line set including at least one sterile sterilizing grade filter, to produce sterile purified water with an amount of bacteria that is zero Colony-Forming Units/mL and an amount of bacterial endotoxins that is less than <NUM> Endotoxin Units/mL. Thus, purified water with a high level of purity can be continually produced. The combination of < <NUM> Colony-Forming Units/mL purified water produced by the water purification apparatus along with the sterile sterilizing grade filter allow for the determination of a probably of a non-sterile unit (PNSU) for the purified water of less than <NUM>-<NUM> on a per treatment basis.

According to some embodiments, the system comprises a cycler, and the method further comprises causing a pump actuator of the cycler to operate a pump chamber of the line set to pump a first amount of the purified water to a mixing container of the line set, and causing the pump actuator to operate the pump chamber to pump a prescribed amount of at least one concentrate from at least one concentrate source to the mixing container. The at least one concentrate are sterile concentrates. Thus, sterile dialysis fluid can be produced using sterile concentrate and sterile purified water. Optionally, the method further comprises causing the pump actuator to operate the pump chamber to pump a second amount of the purified water to the mixing container.

According to some embodiments, the method further comprises heating the produced purified water to a temperature above <NUM>, directing the heated purified water through the water outlet connector and circulating the heated purified water in the line set. Thus, the line set may be heat disinfected such that it can be reused.

According to some embodiments, the method comprises treating the purified water from the RO-unit with an electrodeionization, EDI, unit. The produced purified water from the EDI makes it possible to produce water for injection.

According to a fourth aspect, the disclosure relates to a computer program comprising instructions which, when the program is executed by a control unit, cause the control unit and an thereto associated water producing apparatus to carry out the method as described herein.

According to a fifth aspect, the disclosure relates to a computer-readable medium comprising instructions which, when executed by a control unit, cause the control unit and a thereto associated water producing apparatus to carry out the method.

In the following a system for producing microbiologically controlled fluids will be explained. The system is intended to be used in applications requiring fluids with a high purity level. Such an application is peritoneal dialysis (PD). The risk of microbiological contamination makes it a challenge to produce PD fluids at patients' home. The system should to be designed in such a way that it reduces risk of biofilm formation in the fluid path, reduces microbiological contamination during connection and secures the microbiological control. A ready to use solution should be free from microorganisms and essentially free from bacterial endotoxins.

The disclosure provides in a first aspect a system that provides purified water with a high degree of purity. This is achieved with a heat disinfected water purification apparatus and a line set comprising at least one sterile sterilizing grade filter. The line set is in one embodiment pre-sterilized. The at least one filter is then at least one sterile sterilizing grade filter. In an extended first aspect, the system includes a cycler for providing dialysis fluid with a high degree of purity by mixing the purified water with at least one concentrate. The at least one concentrate is in one embodiment pre-sterilized. The provided dialysis fluid is free from bacteria and essentially free from bacterial endotoxins, thus non-pyrogenic.

The disclosure provides a system and methods to maintain the microbiological control of the system, such that the system can be used continually with maintained purity degree of the produced fluid(s).

The water purification apparatus may in-between treatments be heat disinfected using hot water. This procedure disinfects the fluid circuit including the RO membrane and the fluid path downstream the RO membrane. Frequent hot water disinfection makes it possible to design away from build-up of biofilm in the fluid path, reduces the risk of endotoxin contamination and overall minimizes bioburden of the system.

An exemplary system 10a will now be described with reference to <FIG> and <FIG>. <FIG> illustrates the exemplary system 10a being a peritoneal dialysis system having point of use dialysis fluid production. The system 10a includes a cycler <NUM> and a water purifiying apparatus <NUM>. Suitable cyclers for cycler <NUM> include, e.g., the Amia® or HomeChoice® cycler marketed by Baxter International Inc. , with the understanding that those cyclers need updated programming to perform and use the point of use dialysis fluid produced according to system 10a. To this end, cycler <NUM> includes a control unit <NUM> including at least one processor and at least one memory. Control unit <NUM> further includes a wired or wireless transceiver for sending information to and receiving information from the water purifying apparatus <NUM>. The water purifying apparatus <NUM> also includes a control unit <NUM> including at least one processor and at least one memory. Control unit <NUM> further includes a wired or wireless transceiver for sending information to and receiving information from control unit <NUM> of cycler <NUM>. Wired communication may be via Ethernet connection, for example. Wireless communication may be performed via any of Bluetooth™, WiFi™, Zigbee®, Z-Wave®, wireless Universal Serial Bus ("USB"), or infrared protocols, or via any other suitable wireless communication technology.

Cycler <NUM> includes a housing <NUM>, which holds equipment programmed via control unit <NUM> to prepare fresh dialysis solution at the point of use, pump the freshly prepared dialysis fluid to patient P, allow the dialysis fluid to dwell within patient P, then pump used dialysis fluid to a drain. In the illustrated embodiment, water purifier apparatus <NUM> includes a first drain path <NUM> connected to the drain connector <NUM> for transporting drain fluid received from the drain line <NUM> to a drain <NUM>. The drain <NUM> may be a housing drain or drain container. The equipment programmed via control unit <NUM> to prepare fresh dialysis solution at the point of use in an embodiment includes equipment for a pneumatic pumping system, including but not limited to (i) one or more positive pressure reservoir, (ii) one or more negative pressure reservoir, (iii) a compressor and a vacuum pump actuator <NUM> each under control of control unit <NUM>, or a single pump actuator <NUM> creating both positive and negative pressure under control of control unit <NUM>, for providing positive and negative pressure to be stored at the one or more positive and negative pressure reservoirs, (iv) plural pneumatic valve chambers for delivering positive and negative pressure to plural fluid valve chambers, (v) plural pneumatic pump chambers for delivering positive and negative pressure to plural fluid pump chambers, (vi) plural electrically actuated on/off solenoid pneumatic valves under control of control unit <NUM> located between the plural pneumatic valve chambers and the plural fluid valve chambers, (vii) plural electrically actuated variable orifice pneumatic valves under control of control unit <NUM> located between the plural pneumatic pump chambers and the plural fluid pump chambers, (viii) a heater under control of control unit <NUM> for heating the dialysis fluid as it is being mixed in one embodiment, and (viii) an occluder <NUM> under control of control unit <NUM> for closing the patient and drain lines in alarm and other situations.

In an exemplary embodiment, the plural pneumatic valve chambers and the plural pneumatic pump chambers are located on a front face or surface of housing <NUM> of cycler <NUM>. The heater is located inside housing <NUM> and in an embodiment includes heating coils that contact a heating pan, which is located at the top of housing <NUM>, beneath a heating lid (not seen in <FIG>).

Cycler <NUM> in the illustrated embodiment includes a user interface <NUM>. User interface <NUM> may also include one or more electromechanical input device, such as a membrane switch or other button, or a video monitor <NUM> optionally overlaid with a touch screen. Water purifier <NUM> in the illustrated embodiment also includes a user interface <NUM>. User interface <NUM> may also include one or more electromechanical input device, such as a membrane switch or other button, or a video monitor optionally overlaid with a touch screen.

Referring additionally to <FIG>, one exemplary embodiment of disposable line set <NUM> is illustrated. Disposable set <NUM> is also illustrated in <FIG>, mated to cycler <NUM> to move fluid within the disposable line set <NUM>, e.g., to mix dialysis fluid as discussed herein. Disposable line set <NUM> in the illustrated embodiment includes a disposable cassette <NUM>, which may include a planar rigid plastic piece covered on one or both sides by a flexible membrane. The membrane pressed against housing <NUM> of cycler <NUM> forms a pumping and valving membrane. <FIG> illustrates that disposable cassette <NUM> includes fluid pump chambers <NUM> that operate with the pneumatic pump chambers located at housing <NUM> of cycler <NUM> and fluid valve chambers <NUM> that operate with the pneumatic valve chambers located at housing <NUM> of cycler <NUM>. In an example embodiment, the line set <NUM> is a reusable line set. Thus, the line set <NUM> may be reused one or more times before it is exchanged for another line set <NUM>. The line set <NUM> my thus be seen as semi-disposable, as it can be used more than once. The line set <NUM> is delivered to the user in a sterile format.

<FIG> and <FIG> illustrate that disposable set <NUM> includes a patient line <NUM> that extends from a patient line port of cassette <NUM> and terminates at a patient line connector <NUM>. <FIG> illustrates that patient line connector <NUM> connects to a patient transfer set <NUM>, which in turn connects to an indwelling catheter located in the peritoneal cavity of patient P. Disposable set <NUM> includes a drain line <NUM> that extends from a drain line port of cassette <NUM> and terminates at a drain line connector <NUM>. <FIG> illustrates that drain line connector <NUM> is connected removeably to a drain connector <NUM> of the water purifying apparatus <NUM>.

<FIG> and <FIG> further illustrate that disposable set <NUM> includes a heater/mixing line <NUM> that extends from a heater/mixing line port of cassette <NUM> and terminates at a heater/mixing container <NUM> (or bag). Disposable set <NUM> includes an upstream water line segment 64a that extends to a water inlet 66a of water accumulator <NUM>. A downstream water line segment 64b extends from a water outlet 66b of water accumulator <NUM> to cassette <NUM>. In the illustrated embodiment, upstream water line segment 64a begins at a water line connector <NUM> and is located upstream from water accumulator <NUM>. <FIG> illustrates that water line connector <NUM> is removeably connected to a water outlet connector <NUM> of water purifier <NUM>.

Water purifier <NUM> outputs water and possibly water suitable for peritoneal dialysis ("WFPD"). WFPD is purified water suitable for making dialysis fluid for delivery to the peritoneal cavity of patient P. To ensure WFPD, however, a sterile sterilizing grade filter 70a is placed upstream from a downstream sterile sterilizing grade filter 70b, respectively. Filters 70a and 70b may be placed in water line segment 64a upstream of water accumulator <NUM>. Sterile sterilizing grade filters 70a and 70b may be pass-through filters that do not have a reject line.

In an example embodiment, the at least one sterile sterilizing grade filter 70a, 70b is arranged to filter the purified water into sterile purified water with an amount of bacteria that is zero Colony-Forming Units/mL (CFU/mL) and an amount of bacterial endotoxins that is less than <NUM> Endotoxin Units/mL (EU/mL). The sterilizing grade filters ensures that the water used to prepare the PD fluid for administration meets requirements for sterile non-pyrogenic water. The sterile sterilizing grade filters includes a membrane having pores with average diameters suitable to produce sterile fluid, including the capability of removing endotoxins, resulting in water quality suitable for PD. The sterile sterilizing grade filters provide the final stage of sterilization for the water that is used to mix with the one or more concentrate to provide a dialysis fluid suitable for PD. The mean pore diameter for sterile sterilizing grade filter may, for example, be less than one micrometre, such as <NUM>-<NUM> micrometre, e.g. <NUM> or <NUM> micrometre. Bacteria typically have a diameter of a few micrometres, and will then not pass through the pores. The filter membrane may further comprise a high molecular weight additive bearing cationic charges, for example a cationic charged polymer. Examples of other kinds of positively charged additives can be found in <CIT>. The filter membrane will thus be positively charged. The membrane will then reject bacterial endotoxins, whereby less bacterial endotoxins will pass the membrane. In an exemplary embodiment, bacteria and bacterial endotoxins will also be retained based on adsorption to the membrane. The membrane may be polyethersulfone-based. Other suitable polymers may be AN69, PAN, PMMA, cellulose etc. Suitable sterile sterilizing grade filters 70a and 70b may, for example, be Pall IV-<NUM> or GVS Speedflow filters, or be filters provided by the assignee of the present disclosure. In an exemplary embodiment, only one upstream or downstream sterile sterilizing grade filter 70a and 70b is needed to produce WFPD, nevertheless, two sterile sterilizing grade filters 70a and 70b are provided for redundancy in case one fails. The purified water will then be sterile and have a very low amount of bacterial endotoxins before it is mixed with concentrates when preparing ready to use fluid.

<FIG> further illustrates that a last bag or sample line <NUM> may be provided that extends from a last bag or sample port of cassette <NUM>. Last bag or sample line <NUM> terminates at a connector <NUM>, which may be connected to a mating connector of a premixed last fill bag of dialysis fluid or to a sample bag or other sample collecting container. Last bag or sample line <NUM> and connector <NUM> may be used alternatively for a third type of concentrate if desired.

<FIG> and <FIG> illustrate that disposable set <NUM> includes a first, e.g., glucose, concentrate line <NUM> extending from a first concentrate port of cassette <NUM> and terminates at a first, e.g., glucose, cassette concentrate connector 80a. A second, e.g., buffer, concentrate line <NUM> extends from a second concentrate port of cassette <NUM> and terminates at a second, e.g., buffer, cassette concentrate connector 82a.

<FIG> illustrates that a first concentrate container 84a holds a first, e.g., glucose, concentrate, which is pumped from container 84a through a container line <NUM> to a first container concentrate connector 80b, which mates with first cassette concentrate connector 80a. A second concentrate container 84b holds a second, e.g., buffer, concentrate, which is pumped from container 84b through a container line <NUM> to a second container concentrate connector 82b, which mates with second cassette concentrate connector 82a.

In an embodiment, to begin treatment, patient P loads cassette <NUM> into cycler and in a random or designated order (i) places heater/mixing container <NUM> onto cycler <NUM>, (ii) connects upstream water line segment 64a to water outlet connector <NUM> of water purifier <NUM>, (iii) connects drain line <NUM> to drain connector <NUM> of water purifier <NUM>, (iv) connects first cassette concentrate connector 80a to first container concentrate connector 80b, and (v) connects second cassette concentrate connector 82a to second container concentrate connector 82b. At this point, patient connector <NUM> is still capped. Once fresh dialysis fluid is prepared as described in detail below, patient line <NUM> is primed with fresh dialysis fluid, after which patient P may connect patient line connector <NUM> to transfer set <NUM> for treatment. Each of the above steps may be illustrated graphically at video monitor <NUM> and/or be provided via voice guidance from speakers <NUM>.

For disposable set <NUM>, the rigid portion of cassette <NUM> may be made for example of a thermal olefin polymer of amorphous structure ("TOPAS") cyclic olefin copolymer ("coc"). The flexible membranes of cassette <NUM> may be made for example of a copolyletser ether ("PCCE") and may be of one or more layer. Any of the tubing or lines may be made for example of polyvinyl chloride ("PVC"). Any of the connectors may be made for example of acrylonitrile-butadiene-styrene ("ABS", e.g., for concentrate connectors 80a, 80b, 82a, 82b and heater/mixing bag connector <NUM> discussed below), acrylic (e.g., for drain line connector <NUM>) or PVC (e.g., for water line connector water line connector <NUM>). Any of the bags or containers may be made of PVC. The materials for any of the above components may be changed over time.

<FIG> illustrates that water line connector <NUM> is removeably connected to a water outlet connector <NUM> of water purifier <NUM>. The drain line <NUM> is removeably connected to a drain connector <NUM> of water purifier <NUM>.

The control unit <NUM> of the cycler comprises instructions for mixing the purified water and the at least one concentrate into a PD fluid. The instructions includes to i) cause the pump actuator <NUM> to operate the pump chamber <NUM> to pump a first amount of the purified water to the mixing container <NUM> and ii) cause the pump actuator <NUM> to operate the pump chamber <NUM> to pump a prescribed amount of the at least one concentrate from the at least one concentrate source 84a, 84b to the mixing container <NUM>. In one embodiment, the instructions further comprises to iii) cause the pump actuator <NUM> to operate the pump chamber <NUM> to pump a second amount of the purified water to the mixing container <NUM>. According to an example embodiment, the first and second amounts of the purified water add to a total amount needed for the PD fluid.

<FIG> illustrates the system 10a according to one example embodiment where the system 10a comprises the water purification apparatus <NUM> and the line set <NUM> connected to the drain connector <NUM> and the water outlet connector <NUM> in isolation.

<FIG> illustrates the system 10a according to one example embodiment where the system 10a illustrated in <FIG>, where the system 10a further comprises the first concentrate container 84a and the second concentrate container 84b connected to the line set <NUM>.

The line set <NUM> including the cassette <NUM>, and also the concentrates in the containers 84a, 84b, are sterilized during manufacture and delivered to the patient's home as sterile disposables that may be discarded after being used once. In one embodiment, the line set <NUM> may be used more than once and thus re-used two or three times. The line set <NUM> may then be referred to as semi-disposable. In some embodiments, also the containers 84a, 84b with concentrates are used more than once, such as two or three times.

<FIG> is a schematic of the functional parts of the water purification apparatus <NUM> according to one exemplary embodiment, including a pre-treatment module <NUM>, a reverseosmosis (RO) module <NUM> and a post-treatment module <NUM>. The water purification apparatus <NUM> comprises an inlet port <NUM> for feeding water from a water source <NUM>, e.g. a water tap, into the water purification apparatus <NUM>, for purification of the water. The incoming water from the water source is fed through the inlet port <NUM> into the pre-treatment module <NUM>.

The Pre-treatment module <NUM> treats the incoming water with a particle filter and a bed of activated carbon. The particle filter is arranged to remove particles such as clay, silt and silicon from the incoming water. The particle filter is arranged to prohibit particles in the size of micro meter, optionally also larger endotoxin molecules, from the incoming water. The bed of activated carbon is arranged to remove chlorine and compositions with chlorine from the incoming water, and to absorb toxic substances and pesticides. In an example embodiment, the bed of activated carbon is arranged to remove one or several of hypochlorite, chloramine and chlorine. In a further example embodiment, the bed of activated carbon is also arranged to reduce organic compounds (TOC total organic carbon) including pesticides of the incoming water.

In an exemplary embodiment, the particle filter and the bed of activated carbon are integrated in one single consumable part. The consumable part is for example exchanged on a predefined interval dependent on the incoming water quality. The quality of the incoming water is for example examined and determined by qualified people before the first use of the water purification apparatus <NUM> at a point of care.

Optionally the pre-treatment module <NUM> comprises an ion exchange device for protection of downstream located devices such as a Reverse Osmosis, RO, membrane and a polisher. The pre-treatment module <NUM> thus filters the incoming water and delivers pre-treated water to a downstream located RO-module <NUM>.

The RO-module <NUM> removes impurities from the pre-treated water, such as microorganisms, pyrogens and ionic material from the pre-treated water by the effect of reverse osmosis. The pre-treated water is pressurized by a pump and forced through RO-membrane to overcome the osmotic pressure. The RO-membrane is for example a semi-permeable membrane. Thereby the stream of pre-treated water, called feed water, is divided into a reject stream of water and a stream of permeate water. In an example embodiment, the reject water may be passed via a one or both of a first reject path and a second reject path. The first reject path recirculates reject water back to the feed fluid path of the RO-pump in order to be fed back into RO-device again. The recirculated reject water increases the feed flow to the RO-device, to get a sufficient flow past the reject side of the RO-membrane to minimize scaling and fouling of the RO-membrane. The second reject path directs reject water to drain. This makes the concentration level on the reject side to be sufficiently low to get an appropriate, required, permeate fluid concentration. If the feed water has low content of solutes, part of the drain flow can also be directed back to the inlet side of the RO-membrane and thereby increasing the water efficiency of the water purification apparatus <NUM>. The RO-module <NUM> thus treats the pre-treated water and delivers permeate water to a downstream located post-treatment module <NUM>. In particular, the RO-device reduces the conductivity of the pre-treated water with <NUM>-<NUM>%. For example, if the pre-treated water received to the RO-device has a conductivity of <NUM>-<NUM>/cm, the RO-device reduces this amount to about <NUM>-<NUM>/cm. The permeate water, thus the purified water from the RO-device, will have a conductivity of about <NUM>-<NUM>/cm. According to one exemplary embodiment, the RO-device is capable of purifying the permeate water to have a conductivity of maximum <NUM>/cm. In particular, the RO-device is capable of purifying the permeate water to have a conductivity of maximum <NUM>/cm.

The post-treatment module <NUM> polishes the permeate water in order to further remove ions from the permeate water. The permeate water is polished using a polisher device such as an Electrodeionization, EDI, device or a mixed bed filter device. The EDI-device makes use of electrodeionization for removing ions, from the permeate water, such as aluminum, lead, cadmium, chromium, sodium and/or potassium etc., which have penetrated the RO-membrane. The EDI-device utilizes electricity, ion exchange membranes and resin to deionize the permeate water and separate dissolved ions, i.e. impurities, from the permeate water. The EDI-device produce polished water, polished by the EDI-device to a higher purity level than the purity level of the permeate water. The EDI may have an antibacterial effect of the product water and can reduce the amount of bacteria and bacterial endotoxins in the water due to, among other, the electrical field in the EDI-device. The mixed bed filter device comprises a column, or container, with a mixed bed ion exchange material.

The polished water, herein also referred to as product water, is thereafter ready for being delivered from a water outlet connector <NUM> of the water purification apparatus <NUM> to a point of use of the product water. The product water is suitable for dialysis, i.e. water for dialysis. In one embodiment, the product water is suitable for injection, i.e. water for injection. The drain connector <NUM> is in one example embodiment used for receiving used fluid, e.g. from a PD patient, via a drain line <NUM>, for further transport via a first drain path <NUM> of the water purification apparatus <NUM> to a drain <NUM> of the water purification apparatus <NUM>. In particular, the polisher device reduces the conductivity of the permeate water to <NUM>-<NUM>%. For example, if the permeate water received to the polisher device has a conductivity of <NUM>-<NUM>/cm, the polisher device reduces this amount to about <NUM>/cm. The polished water, thus the purified water from the polisher device, will thus have a conductivity of about <NUM>/cm. According to one exemplary embodiment, the polisher device is capable of purifying the water to have a conductivity less than <NUM>/cm at <NUM>ºC. In one example embodiment, the water purifying apparatus <NUM> does not include the polisher device such as the EDI unit <NUM>, but is capable of producing water for dialysis.

The minimum requirements for water for haemodialysis and related therapies are defined in ANSI/AAMI <NUM>:<NUM> and ISO <NUM>:<NUM>. The requirements include limits on a plurality of contaminants, such as chlorine, bacteria, bacterial endotoxins, chemical contaminants and heavy metal. For example, the amount of chlorine/chloramine should be less than <NUM>/L, the amount of bacteria shall be less than <NUM> CFU/mL and the amount of bacterial endotoxins shall be less than <NUM> EU/mL.

The requirements for water for injection is for example defined in the Official Monographs for water, United States Pharmacopeia (USP) <NUM> National Formulary (NF) <NUM> (August <NUM>, <NUM>). The requirements include recommended temperature dependent limits on the water conductivity, the amount of Total Organic Carbon and amount of bacterial endotoxins. The limit on water conductivity is defined in USP <NUM> (August <NUM>, <NUM>). For example, at 20ºC the conductivity of the water should be less than <NUM>/cm, at 25ºC the conductivity of the water should be less than <NUM>/cm etc. The amount of Total Organic Carbon (TOC) should be less than <NUM>/L (500ppb), the amount of bacteria should be less than <NUM> CFU/mL and the amount of bacterial endotoxins should be less than <NUM> EU/mL.

In order to produce WFPD, the limits on bacteria and bacterial endotoxins are even more demanding. The amount of bacteria should be zero CFU/mL, thus, the water has to be sterile. The amount of bacterial endotoxins should be less than <NUM> EU/mL. In other words, the sterile purified water should be non-pyrogenic.

In one exemplary embodiment, the water outlet connector <NUM> and the drain connector <NUM> are recessed in the cabinet wall of the water purification apparatus <NUM>. Also, a door (not shown) covers the connectors <NUM>, <NUM> when the connectors <NUM>, <NUM> are not connected to the line set <NUM>. Thereby the connectors <NUM>, <NUM> are more shielded from contamination from the exterior, such as touch contamination and dust.

The disposable line set <NUM> is arranged with at least one sterile sterilizing grade filter set 70a, 70b, for filtering the product water from the water purification apparatus <NUM> to ensure sterility of the produced purified water, and a very low amount of bacterial endotoxins. Thus, the product water collected in the accumulator bag <NUM> has passed through one or several sterile sterilizing grade filters of the disposable line set <NUM> for removal of bacteria and bacterial endotoxins, i.e. to produce sterile purified water. According to one embodiment, the sterile sterilizing grade filters are redundant. By collecting the sterile product water in the accumulator bag <NUM>, the water purification apparatus <NUM> and the cycler <NUM> are decoupled in terms of pressure, so that the high pressure needed to push water through the sterile sterilizing grade filters does not affect the cycler <NUM>. The at least one sterile sterilizing grade filter 70a, 70b ensures that the water used to prepare the PD fluid for administration meets requirements for sterile, non-pyrogenic water (<NUM> CFU/mL and <<NUM> EU/mL).

<FIG> illustrates an example embodiment of the water purification apparatus <NUM>. In other embodiments, the water purification apparatus <NUM> may include less or more components or modules. The water purification apparatus <NUM> of <FIG> receives water from a water source <NUM> (<FIG>), such as a continuous source of potable or drinkable water from a patient's home. In various embodiments, water purification apparatus <NUM> may be installed in a room having access to the water source <NUM> to provide WFPD to cycler <NUM> as discussed herein. The water is optionally pre-filtered using a particle pre-filter <NUM> to remove dirt and sediment, before it is delivered to the water purification apparatus <NUM>. The water enters the water purification apparatus <NUM> via the water inlet port <NUM>. As previously described, the water purification apparatus <NUM> includes a pre-treatment module <NUM>, a RO module <NUM> and a post-treatment module <NUM>. The pre-treatment module <NUM> includes a pre-filter circuit <NUM> connected to a water inlet <NUM> for receiving water from the water source <NUM>, a particle filter and an activated carbon filter, i.e. a bed of activated carbon, arranged to filter water received via the water inlet <NUM> to produce pre-treated water. The particle filter and the activated carbon filter are embodied in one single filter package <NUM>. The single package <NUM> is a disposable package. The pre-filter circuit <NUM> may also comprise a softener using for example ion exchange. The pre-filter circuit <NUM> includes an inlet valve <NUM> and a constant flow device <NUM> upstream the filter package <NUM>. The inlet valve <NUM> controls the feed water inflow by control of the control unit <NUM>. The constant flow device <NUM> provides a constant flow to the tank <NUM> providing that the water pressure is above a minimum pressure for constant flow device <NUM>. Further, the pre-filter circuit <NUM> comprises a tank valve <NUM>, a pre-treatment conductivity sensor <NUM> and a feed water temperature sensor <NUM> downstream the filter package <NUM>. The tank valve <NUM> controls the flow of pre-treated water to the tank <NUM>. The pre-treatment conductivity sensor <NUM> monitors the conductivity of the pre-treated water, and the water temperature sensor <NUM> monitors the temperature of the pre-treated water. The temperature of the pre-treated water is for example needed to calibrate the conductivity measurement of the pre-treated water. The pre-treatment circuit <NUM> is connected to the water inlet port <NUM> and ends into the tank <NUM>. The inlet valve <NUM> and the tank valve <NUM> are configured to be controlled by the control unit <NUM> of the water purification apparatus <NUM>. Water softening in the pre-treatment circuit <NUM> may alternatively or additionally be achieved using lime softening, ionexchange resins or an anti-scalant such as polyphosphate, as known in the art.

The water purifying apparatus <NUM> further comprises a fluid circuit <NUM> arranged to receive pre-treated water from the pre-filter circuit <NUM>. The fluid circuit <NUM> comprises at least some of the parts of the RO module <NUM> and at least some of the parts of the post-treatment module <NUM>. In particular, the fluid circuit <NUM> comprises an RO-pump <NUM> and a Reverse Osmosis, RO, device, <NUM>. The fluid circuit <NUM> also comprises the tank <NUM>. The water purifying apparatus <NUM> is further arranged to pump pre-treated water through the RO device <NUM> using the RO-pump <NUM>, to produce purified water, and output the purified water through a water outlet connector <NUM>. In an exemplary embodiment, the fluid circuit <NUM> is arranged to produce purified water with an amount of bacteria that is less than <NUM> CFU/mL and an amount of bacterial endotoxins that is less than <NUM> EU/mL. This is achieved by means of the RO device <NUM>. The polisher device, such as the EDI device <NUM>, may be capable of further reducing the amount of bacteria and bacterial endotoxins.

A RO-device <NUM> has already been described in detail with reference to the <FIG> and reference is made to that description for further explanation. The pre-treated water enters the tank <NUM>, for example from an upper part of the tank <NUM>. Pre-treated water is accumulated in the tank <NUM> and pumped by the RO-pump <NUM> to the feed inlet 301a of the RO-device <NUM>. A line <NUM> is connected to the bottom of the tank <NUM> and the feed inlet 301a. The RO-pump <NUM> is fitted to the line <NUM>.

The RO-pump <NUM> is configured, under control of the control unit <NUM>, to provide the water flow and pressure requisite for the reverse osmosis process taking place at RO-device <NUM>. As previously described e.g. with reference to <FIG>, the RO-device <NUM> filters water to provide purified water at its permeate outlet 301b. Reject water leaving RO-device <NUM> at a reject outlet 301c (the reject water may be fed back into RO-pump <NUM> to conserve water consumption or alternatively be pumped to drain <NUM>).

Purified water leaving the RO-device <NUM> is transported in a purified fluid circuit <NUM>, of the fluid circuit <NUM>, inside the water purification apparatus <NUM> before being output through the water outlet connector <NUM>, that is, a port. The purified fluid circuit comprises permeate fluid path 371a, polisher fluid path 371b and product fluid path 371c. The EDI-device <NUM> may be by-passed via the bypass path 371d. The bypass path 371d is connected to the purified fluid circuit <NUM> upstream the EDI-device <NUM>, and to the purified fluid circuit downstream the EDI-device <NUM>. Purified water leaving the RO-device <NUM> passes a flow sensor <NUM>, a heating device <NUM>, and a permeate temperature sensor <NUM>, included in the permeate fluid path 371a. The flow sensor <NUM> monitors the flow of the purified fluid leaving the RO-device <NUM>. The heating device <NUM>, heats, by control of the control unit <NUM>, the purified water leaving the RO-device <NUM>. The permeate temperature sensor <NUM> monitors the temperature of the purified fluid leaving the RO-device <NUM> directly downstream the heating device <NUM>. An additional conductivity sensor <NUM> monitors the conductivity of purified water leaving RO-device <NUM>.

Downstream the heating device <NUM>, the permeate temperature sensor <NUM> and the additional conductivity sensor <NUM>, the purified fluid enters the post-treatment module <NUM> via the polisher fluid path 371b. The post-treatment module <NUM> comprises the polisher device, e.g. the EDI-device <NUM>. The three-way valve 305c is arranged to be controlled by the control unit <NUM> to selectively direct the purified fluid flow into either the EDI-device <NUM>, or into the bypass path 371d in order to bypass the EDI-device <NUM>. When directed to the EDI-device <NUM>, the purified fluid enters the product channel 306a, the concentrate channel 306b and the electrode channel 306c of the EDI-device <NUM>. The purified fluid is fed to all the channels via the polisher fluid path 371b downstream the three-way valve 305c. The EDI-device <NUM> is configured to produce purified water, here also referred to as product water. The produced product water leaves the EDI-device <NUM> and enters the product fluid path 371c. A product channel valve <NUM> regulates the flow rate of the product water in the product fluid path 371c from the product channel 306a. The concentrate fluid path 377c is arranged to pass concentrate water and the electrode fluid back to the tank <NUM>. Thus, the fluid circuit <NUM> may include an EDI unit, <NUM> arranged to further treat the purified water from the RO device <NUM> and output further purified water. The fluid circuit <NUM> is arranged to output the purified water from the EDI unit <NUM> through the water outlet connector <NUM>. The purified water is thus passed to the water outlet connector <NUM>, and further into a thereto connected water line <NUM> (64a, 64b) of the fluid line set <NUM> for transport to the point of care. The fluid line set <NUM> comprises two sterile sterilization filters 70a, 70b. The sterile sterilization filters 70a, 70b filter the product water leaving the water outlet connector <NUM> into sterilized product water that is suitable for injection. According to some alternative embodiments the number of filters is less or more than two.

A drain connector <NUM> defines a first drain path <NUM> to the drain <NUM>. A drain line <NUM> of the fluid line set <NUM> is connected to the drain connector <NUM>, in order to pass fluid, such as used PD-fluid, from the drain connector <NUM> to the drain <NUM>. The first drain path <NUM> here embodies the part of a cycler drain path that is present inside the water purification apparatus <NUM>.

The flow control device 305a is configured to control the flow rate of purified water in the recirculation path <NUM> arranged from a point downstream the heater <NUM>, the permeate temperature sensor <NUM> and the additional conductivity sensor <NUM>, and back to the tank <NUM>. A product water pressure sensor <NUM> is arranged to monitor the pressure in the product fluid path 371c downstream the EDI-device <NUM>. A product water flow sensor <NUM> is arranged to monitor the flow rate of the product water downstream the EDI-device <NUM>. The pressure and the flow rate of the product water are feed to the control unit <NUM>. The control unit <NUM> is configured to control the operation of the flow control device 305a. More particularly the control unit is configured to regulate the flow rate in the recirculation path <NUM> based on the pressure and flow rate of the product water, in order to control the flow rate of the product water to a desired flow rate, and the pressure of the product water to a desired pressure. The flow control device 305a is for example a motorized flow control valve that is configured to finely regulate the flow rate in the recirculation path <NUM>.

A product water valve 305d is arranged to, by control of the control unit <NUM>, control the produced product flow to go to either the water outlet connector <NUM>, or back to the tank <NUM> via an additional recirculation path, here a first recirculation path <NUM>. An emptying valve <NUM> is arranged to control the flow rate in the first recirculation path <NUM>. The first recirculation path <NUM> is fluidly connected to the product fluid path 371c via an air-trap chamber <NUM>. A product water conductivity sensor <NUM> is arranged to monitor the conductivity of the product water upstream the air-trap chamber <NUM>. A product fluid temperature sensor <NUM> is configured to monitor the temperature of the product water upstream the air-trap chamber <NUM>.

In operation, a portion of the rejected water leaves the RO-device <NUM> via a fluid path 385a and a three-way valve 305b (e.g. a three-way solenoid valve) under control of control unit <NUM>. A remaining portion of the rejected water returns to RO-pump <NUM> via a valve <NUM> (e.g., a manual needle valve) in a first reject path 385b. Three-way valve 305b is configured to selectively divert the rejected water either to drain <NUM> via a second drain path <NUM> or back to tank <NUM> via a second reject path <NUM>.

All meters and sensors described in connection with water purification apparatus <NUM> in <FIG> are configured to send their corresponding signals to control unit <NUM>.

The water purification apparatus <NUM> includes a container <NUM> containing a microbiological growth inhibiting agent. As illustrated, container <NUM> is in fluid communication with an inlet 392a of the water purification apparatus <NUM>. In <FIG>, the chemical intake path <NUM> connects container <NUM> to the fluid path of the water purification apparatus <NUM>. Alternatively, container <NUM> may be connected via a line (not illustrated) leading directly to disposable cassette <NUM> operating with cycler <NUM>, or be connected to water line <NUM>, or be connected to drain line <NUM>. The agent inhibiting microbiological growth in the container <NUM> may be a suitable physiologically safe acid, such as citric acid, citrate, lactic acid, acetic acid, or hydrochloric acid (or a combination thereof). In one embodiment, container <NUM> contains citric acid, citrate or a derivative thereof. It is noted that container <NUM> may also include additives provided together with the acid (such as with citric acid). The chemical inlet 392a, is located for example at the front of water purification apparatus <NUM>. The three-way valve <NUM>, under control of control unit <NUM>, at chemical inlet 392a is arranged to open towards a second pump <NUM> being a chemical intake pump, and tank <NUM>. The second pump <NUM> is arranged to feed disinfecting solution into tank <NUM>. Three-way valve <NUM> under control of control unit <NUM> may also be used to recirculate water and disinfectant from and to tank <NUM> during the phases of chemical disinfection (i.e. disinfection with a cleaning agent), cleaning and/or rinse. The second pump <NUM> and a valve <NUM> are arranged in a path <NUM> fluidly connecting the three-way valve <NUM> and the product fluid path 371c. The valve <NUM> is arranged to control the flow in the path <NUM>.

In a more detailed disinfection phase example, when chemical disinfection is initiated, the level in tank <NUM> is adjusted to a low level. Control unit <NUM> causes RO-pump <NUM> to start and run until the tank <NUM> is empty or almost empty. RO-pump <NUM> is then stopped and inlet valve <NUM> is opened. Inlet valve <NUM> is maintained open, and the second pump <NUM> is then run until a preset amount of chemical solution is metered into tank <NUM>. When the level in tank <NUM> reaches a pre-determined level, the three-way valve <NUM> is opened to drain <NUM>. RO-pump <NUM> circulates the fluid in the fluid circuit during the chemical intake phase and may be operated in two directions to create turbulent flow and to increase disinfection time and contact. At the end of the intake phase, reject bypass valve <NUM> is opened and the three-way valve 305b is actuated to open second drain path <NUM> to drain <NUM> and to drain the water level in tank <NUM> to a low level.

The described pre-treatment module <NUM>, the RO module <NUM> and post-treatment module <NUM>, are enclosed inside of a single integrated water purification cabinet 110a, except for the filter package <NUM>, which is removably arranged, e.g. hinged, on the outside of the single water purification cabinet 110a. However, the water purification apparatus <NUM> is considered as being integrated in the sense that it is compact and built as one unit. The filter package <NUM> may then be exchanged when exhausted. In an alternative embodiment, the modules may be arranged in separate units. As mentioned above, purified water is sent from water purification apparatus <NUM> to disposable set <NUM> via water line <NUM>. Referring to <FIG>, water line <NUM> feeds purified water to a water port <NUM> of cassette <NUM> of disposable set <NUM>. Water line <NUM> is in one embodiment a flexible tube having a first end connected to the water outlet connector <NUM> of the water purification apparatus <NUM> and a second end connected to a water port <NUM> of the cycler <NUM>. Water line <NUM> may be at least <NUM> meters long and in one embodiment longer than <NUM> meters. Water line <NUM> allows water purification apparatus <NUM> to be installed in a room having an available water source, while cycler <NUM> resides in a different room in which the patient resides, e.g., sleeps. Water line <NUM> may accordingly be as long as necessary to connect water purification apparatus <NUM> to cycler <NUM>.

<FIG> also illustrates that the disposable line set <NUM> includes a drain line <NUM> configuration arranged to conduct fluid, such as used dialysis fluid, to the drain <NUM> of the water purification apparatus <NUM>. Drain line <NUM> is e.g. a tube having a first end connected to cassette <NUM> of cycler <NUM> and a second end including a drain line connector <NUM> (<FIG>) connected to a drain connector <NUM> of the water purification apparatus <NUM>. Drain line <NUM> may alternatively be a flexible tube, which may be more than <NUM> meters long and in some embodiments longer than <NUM> meters. Drain line <NUM> may be as long as necessary to connect between water purification apparatus <NUM> and cycler <NUM>. Water line <NUM> and drain line <NUM> in the illustrated embodiment run parallel using dual lumen tubing. It is also possible that water purification apparatus <NUM> and cycler <NUM> are positioned close together, such that the same two line fluid path including water line <NUM> and drain line <NUM> may for example be less than <NUM> meters. Moreover, while a dual lumen water line <NUM> and the drain line <NUM> are illustrated, it is possible that water line <NUM> and drain line <NUM> are separate. A water tray <NUM> is positioned below the water purification apparatus <NUM>. A liquid sensor <NUM> is arranged at the bottom of the water tray <NUM> to detect any leakage from the water purification apparatus <NUM>. In one example embodiment, the water tray <NUM> is enclosed inside the purification cabinet 110a of the water purification apparatus <NUM>.

As described, the fluid circuit <NUM> includes the heating device <NUM> arranged to heat purified water from the RO device <NUM>. The heating device <NUM> may heat the water to a suitable disinfection temperature above <NUM>, for example between <NUM> and <NUM>. The water may be heated to such a temperature directly by having a powerful heating device <NUM>. Alternatively, the water may be gradually heated, recirculated to the tank <NUM>, pumped by the RO-pump <NUM> through the membrane <NUM> and again heated by the heating device <NUM>. The water purifying apparatus <NUM> is further arranged to heat disinfect the fluid circuit <NUM> using the heated purified water. The heated water is then circulated in the fluid circuit <NUM>. The fluid circuit <NUM> may include the drain connector <NUM> and the water outlet connector <NUM>. The water purifying apparatus <NUM> may then be arranged to heat disinfect the drain connector <NUM> and the water outlet connector <NUM> using the heated purified water. A door (not shown) is closed over the drain connector <NUM> and the water outlet connector <NUM> from the outside of the water purifying apparatus <NUM>. When a contact sensor <NUM> (<FIG>) such as a Hall sensor, detects that the door is closed, disinfection of the fluid circuit <NUM> and/or the connectors <NUM>, <NUM> may be performed. Heated water is passed via the connectors <NUM>, <NUM> and between the connectors <NUM>, <NUM> via an internal bypass line 401a, such that the inside and the outside of the connectors <NUM>, <NUM> are disinfected in the same disinfection run.

In an example embodiment, the control unit <NUM> of the water purifying apparatus <NUM> is programmed to periodically instruct the water purifying apparatus <NUM> to heat the purified water flowing in the fluid circuit <NUM> by means of the heating device <NUM> to a temperature above <NUM> and to control heat disinfection of the fluid circuit <NUM> using the heated water such that a certain disinfection criterion is met. The control unit <NUM> may initiate the heat disinfection automatically, or by instructions/commands from the cycler <NUM>. The disinfection may also be initiated manually by the user. The disinfection criterion may include that the fluid circuit should be heat disinfected for a certain time with a certain temperature of the heated water. The time and temperature may for example be determined according to the well known A0 concept. The A0 concept is defined as: <MAT> z is a value defined by the type of microorganisms that need to be killed. For bacterial spores, which is the most resistant of all microorganisms, a z-value of z=10º is considered needed. At a temperature T of 80ºC, the A0 expresses the time, Δt is seconds, needed to reach an expected effect. If T=90ºC, only a tenth of the time is needed, i.e. <NUM> seconds, to get an A0 of <NUM>. If T instead is 70ºC, the time needed is tenfold. An A0 value of <NUM> should be sufficient for disinfection when one patient is considered. However, an A0 value of <NUM>, or more, may also be considered. All temperatures above <NUM>ºC are considered to have a disinfection effect and should be included in the calculation of A0. The water may thus be heated to a temperature above <NUM>ºC, for example between <NUM>ºC and <NUM>ºC, and thus below boiling.

The connectors <NUM>, <NUM> are typically disinfected each time the line set <NUM> has been disconnected from the connectors <NUM>, <NUM>, and the door (not shown) has been closed. The whole fluid circuit <NUM>, including the RO membrane, the recirculation loops <NUM>, <NUM>, optionally the EDI <NUM>, is disinfected <NUM> to <NUM> times each week, e.g. every second day. The whole fluid circuit <NUM> may include all circuit elements in the water purification apparatus <NUM> except the pre-treatment circuit <NUM>.

In an alternative embodiment, the line set <NUM> is not changed after each treatment. Instead, the line set <NUM> is re-used two, three or four times before it is exchanged. The line set <NUM> will then remain connected to the water purification apparatus <NUM>. The line set <NUM> has to be disinfected after every treatment, and in one exemplary embodiment the control unit <NUM> is programmed to instruct the water purifying apparatus <NUM> to heat water flowing in the fluid circuit <NUM> by means of the heating device <NUM> and to output the heated water through the purified water outlet connector <NUM> to the line set <NUM> for heat disinfection of the line set <NUM>. The heated water is then collected in the accumulator bag <NUM>, and pumped to the mixing container <NUM> by means of the pump actuator <NUM> of the cycler <NUM>, which is included in the instructions of the control unit <NUM> of the cycler <NUM>. The control unit <NUM> of the cycler <NUM> may also comprise instructions for performing a heat disinfection of the line set <NUM>. The instructions include to cause (i) the pump actuator <NUM> to pull heated water from the mixing container <NUM> into the pump chamber <NUM>, cause (ii) the pump actuator <NUM> to operate the pump chamber <NUM> to push the hot water into the mixing container <NUM>, and repeat (i) and (ii) at least one time. Thereby the heated water will flow in and out of the mixing container <NUM> to thoroughly heat disinfect the same. In one embodiment, the heat disinfection of the line set <NUM> should meet the same kind of disinfection criterion as of the fluid circuit <NUM> of the water purification apparatus <NUM>, for example defined according to the A0 concept.

In the following a method for producing microbiologically controlled fluid with a system, for example the previously described system, will be explained with reference to the flowchart of <FIG>. The system comprises a water purifying apparatus <NUM> with a heat disinfected fluid circuit <NUM> arranged for producing purified water, and a line set <NUM> connected to a water outlet connector <NUM> of the water purifying apparatus <NUM> for transporting the purified water to a point of use. The method may be implemented by a computer program comprising instructions which, when the program is executed by one or both of the described control units, cause one or both of the control units and the system as has been described to carry out the method according to any of the embodiments as described herein. The method may reside in a computer-readable medium. The computer-readable medium comprises instructions which, when executed by one or both of the control units, cause the one or both of the control units and the system to carry out the method according to any of the embodiments as described herein.

It is here presumed that the fluid circuit of the water purification apparatus has already been heat disinfected. Otherwise, the method may be initiated by performing S0 a heat disinfection of the fluid circuit <NUM>, optionally including the connectors <NUM>, <NUM>. If the line set <NUM> is connected to the connectors <NUM>, <NUM>, the line set <NUM> may as well be heat disinfected. After the heat disinfection, and if the line set <NUM> was not connected, the user connects the line set <NUM> to the connectors <NUM>, <NUM>. Thereafter the water purification apparatus is ready to start producing purified water. The method comprises treating S1 water from a water source <NUM> with a RO unit <NUM> of the fluid circuit <NUM> to produce purified water from the RO unit <NUM>, thus permeate water. The pre-filtered water is thus pushed through the membrane <NUM> of the RO unit <NUM>, by means of the RO pump <NUM>. In one exemplary embodiment, the method further comprises treating S2 the permeate water with a polisher device of the fluid circuit. The polisher device is for example an EDI device. The permeate water is pushed through the EDI by means of the RO pump <NUM>. The produced purified water has an amount of bacteria that is less than <NUM> CFU/mL and an amount of bacterial endotoxins that is less than <NUM> EU/mL. If a polisher device is used, the polisher device may be capable of assisting in reducing, or further reducing, the amount of bacteria and endotoxins. In a further step, the method comprises directing S3 the purified water through the purified water outlet connector and the thereto connected line set <NUM> including at least one sterile sterilizing grade filter 70a, 70b, to produce sterile purified water with an amount of bacteria that is zero CFU/mL and an amount of bacterial endotoxins that is less than <NUM> EU/mL. This is achieved by providing the membrane of the filter/filters with certain characteristics such as a pore size less than one micrometer and a high molecular weight additive bearing cationic charges. The line set <NUM> accumulates the purified water in the accumulator bag <NUM>.

In an exemplary embodiment, the line set <NUM> is arranged to operate with a pumping actuator <NUM> of a cycler <NUM>. At least one concentrate source 84a, 84b is further connected to the line set <NUM>. The method may then comprise causing S41 the pump actuator <NUM> of the cycler <NUM> to operate the pump chamber <NUM> of the line set <NUM> to pump a first amount of the purified water, from the accumulator bag <NUM>, to a mixing container of the line set <NUM>. To mix the purified water with concentrates, the method comprises causing S42 the pump actuator <NUM> to operate the pump chamber <NUM> to pump a prescribed amount of at least one concentrate from at least one concentrate source 84a, 84b to the mixing container <NUM>. In one example embodiment, the method further comprises causing S43 the pump actuator <NUM> to operate the pump chamber <NUM> to pump a second amount of the purified water to the mixing container <NUM>. The fluid may then be mixed by sequentially pumping in and out some fluid from the mixing container <NUM>. The ready-mixed PD fluid is then ready to be infused into the patient P. By means of the pump actuator <NUM>, the PD-fluid is infused into the patient P.

The disposable set including the one or more sterile sterilizing grade filter is discarded after each use in one embodiment. In alternative embodiments, the disposable set including the cassette, associated lines, heater/mixing bag, water accumulator (if provided) and one or more sterile sterilizing grade filter are reused for one or more additional treatment. To do so, it is contemplated to flush the disposable cassette with purified water at the end of treatment to push residual used dialysis fluid from the cassette and the drain line to drain. The patient disconnects the patient line from the patient's transfer set (which leads to the patient's indwelling peritoneal catheter) and caps the transfer set and patient line each with a cap, e.g., a cap containing a disinfectant. In an alternative embodiment, the drain line, for example, is provided with a port for connecting to the end of the patient line between treatments to create a patient line loop that may be more effectively flushed or disinfected. The concentrate lines of the cassette are left connected to the concentrate containers. The water line from the cassette is left connected to the water purifier. The drain line from the cassette is left connected to drain, e.g., via a drain line connection to the water purifier having the at least one conductivity sensor as discussed herein.

The line set <NUM> may now be disinfected such that it can be used again. In one exemplary embodiment, the method comprises heating S5 the produced purified water to a temperature above <NUM>, directing S6 the heated purified water through the water outlet connector <NUM> and circulating S7 the heated purified water in the line set <NUM>, in order to heat disinfect the line set <NUM>. The method may additionally comprise to heat disinfect the fluid circuit <NUM> as has been previously described, including the RO membrane, in the same run or during the same disinfection cycle. The heated water is delivered to the water accumulator <NUM> in one embodiment. The cycler <NUM> in its last step at the end of treatment pulls heated purified water from the water accumulator <NUM> and pumps the water into and through the cassette, drain line and possibly even the heater/mixing container.

In an embodiment, control unit <NUM> of cycler <NUM> is programmed to cause cycler <NUM> to push and pull the heated water repeatedly throughout cassette <NUM> and heater/mixing bag <NUM>, and repeatedly through water line segments 64a and 64b. The hot water is also cycled through drain line <NUM> and patient line <NUM>, e.g., up to a hydrophobic membrane located in patient line connector <NUM>. The heat disinfection of the fluid line set <NUM> may be continued until a certain disinfection criterion is met S9. If the criterion is fulfilled, the heat disinfection of the line set is stopped and the heated water directed to drain. If the criterion is not fulfilled, the heat disinfection is continued. The criterion may include that the hot water should be circulated for a certain time with a certain temperature. For example, the temperature should be between <NUM>ºC and <NUM>ºC, and the time between <NUM> and <NUM> hours. The time and temperature may be determined according to the A0 concept, as known in the art. When the hot water disinfection of semi-disposable set <NUM> is completed, the hot water is sent to drain <NUM> at the water purification apparatus <NUM>.

In an embodiment, a supply of the bacterial growth prevention agent is connected as an input to the water purification apparatus <NUM>. The water purification apparatus <NUM> as a last step at the end of treatment mixes a desired amount of the bacterial growth prevention agent into the purified water, which is then delivered to the water accumulator <NUM> in one embodiment. The water may also be heated by the heating device in the water purification device <NUM> to a high temperature as has been previously described. The cycler <NUM> in its last step at the end of treatment pulls purified water including the growth inhibitor from the water accumulator <NUM> and pumps the water and inhibitor into and through the cassette, drain line and possibly even the heater/mixing container, that is, performs the same procedure as has been described in connection with disinfection with heated purified water only. After the disinfection is finished, the used water is passed to drain <NUM>.

In an embodiment, the number of times that the disposable set may be reused is keyed off of the level of concentrates in the concentrate containers. For example, the concentrate containers may be configured to hold and provide three treatment's worth of concentrate (plus some extra to ensure three full treatments). It is therefore intended that the disposable set be reused two times, so that at the end of three treatments, the patient may simply remove the disposable set with concentrate containers connected from the cycler for disposal, and reconnect a new disposable set along with two new concentrate containers. It is contemplated that the control unit of the cycler keep track of the amount of each concentrate consumed over the three treatment period so that the control unit may (i) prevent the user from beginning a treatment when there is not enough of either concentrate to complete the treatment and/or (ii) provide an option to the user to perform a treatment with one or more less cycles.

Claim 1:
A system comprising
▪ an integrated water purifying apparatus (<NUM>) comprising:
• a pre-filter circuit (<NUM>) connected to a water inlet (<NUM>) for receiving water from a water source (<NUM>), a particle filter and an activated carbon filter arranged to filter water received via the water inlet (<NUM>) to produce pre-treated water;
• a fluid circuit (<NUM>) arranged to receive pre-treated water from the pre-filter circuit (<NUM>), the fluid circuit (<NUM>) includes
∘ an RO-pump (<NUM>); and a
∘ a Reverse Osmosis, RO, device, (<NUM>)
the water purifying apparatus (<NUM>) is further arranged to pump pre-treated water through the RO device (<NUM>) using the RO-pump (<NUM>), to produce purified water, and output the purified water through a purified water outlet connector (<NUM>); the fluid circuit (<NUM>) further includes
∘ a heating device (<NUM>) arranged to a permeate fluid path (371a) to heat purified water from the RO device (<NUM>) to a temperature above <NUM>;
the water purifying apparatus (<NUM>) is further arranged to heat disinfect the fluid circuit (<NUM>) using the heated purified water; the system (10a) further comprises:
▪ a line set (<NUM>) connected to the purified water outlet connector (<NUM>) at a water line connector (<NUM>) of the line set (<NUM>), wherein the line set (<NUM>) includes at least one sterile sterilizing grade filter (70a, 70b) arranged to filter the purified water into sterile purified water.