Patent Description:
Dialysis treatment for replacement of kidney function is critical to many people because the treatment is life saving.

One type of kidney failure therapy is hemodialysis ("HD"), which in general uses diffusion to remove waste products from a patient's blood.

Most HD (HF, HDF) treatments occur in centers. A trend towards home hemodialysis ("HHD") exists today in part because HHD can be performed daily, offering therapeutic benefits over in-center hemodialysis treatments, which occur typically bi- or triweekly. Studies have shown that more frequent treatments remove more toxins and waste products than a patient receiving less frequent but perhaps longer treatments. A patient receiving more frequent treatments does not experience as much of a down cycle as does an in-center patient, who has built-up two or three day's worth of toxins prior to a treatment. In certain areas, the closest dialysis center may be many miles from the patient's home, causing door-to-door treatment time to consume a large portion of the day. HHD can take place overnight or during the day while the patient relaxes, works or is otherwise productive.

Another type of kidney failure therapy is peritoneal dialysis ("PD"), which infuses a dialysis solution, also called dialysis fluid, into a patient's peritoneal cavity via a catheter. The dialysis fluid contacts the peritoneal membrane of the peritoneal cavity. Waste, toxins and excess water pass from the patient's bloodstream, through the peritoneal membrane, and into the dialysis fluid due to diffusion and osmosis, i.e., an osmotic gradient occurs across the membrane. An osmotic agent in the PD dialysis fluid provides the osmotic gradient. Used or spent dialysis fluid is drained from the patient, removing waste, toxins and excess water from the patient. This cycle is repeated, e.g., multiple times.

There are various types of peritoneal dialysis therapies, including continuous ambulatory peritoneal dialysis ("CAPD"), automated peritoneal dialysis ("APD"), tidal flow dialysis and continuous flow peritoneal dialysis ("CFPD"). CAPD is a manual dialysis treatment. Here, the patient manually connects an implanted catheter to a drain to allow used or spent dialysis fluid to drain from the peritoneal cavity. The patient then switches fluid communication so that the patient catheter communicates with a bag of fresh dialysis fluid to infuse the fresh dialysis fluid through the catheter and into the patient. The patient disconnects the catheter from the fresh dialysis fluid bag and allows the dialysis fluid to dwell within the peritoneal cavity, wherein the transfer of waste, toxins and excess water takes place. After a dwell period, the patient repeats the manual dialysis procedure, for example, four times per day. Manual peritoneal dialysis requires a significant amount of time and effort from the patient, leaving ample room for improvement.

Automated peritoneal dialysis ("APD") is similar to CAPD in that the dialysis treatment includes drain, fill and dwell cycles. APD machines, however, perform the cycles automatically, typically while the patient sleeps. APD machines free patients from having to manually perform the treatment cycles and from having to transport supplies during the day. APD machines connect fluidly to an implanted catheter, to a source or bag of fresh dialysis fluid and to a fluid drain. APD machines pump fresh dialysis fluid from a dialysis fluid source, through the catheter and into the patient's peritoneal cavity. APD machines also allow for the dialysis fluid to dwell within the cavity and for the transfer of waste, toxins and excess water to take place. The source may include multiple sterile dialysis fluid solution bags.

APD machines pump used or spent dialysate from the peritoneal cavity, though the catheter, and to the drain. As with the manual process, several drain, fill and dwell cycles occur during dialysis. A "last fill" may occur at the end of the APD treatment. The fluid may remain in the peritoneal cavity of the patient until the start of the next treatment, or may be manually emptied at some point during the day.

In any of the above modalities using an automated machine, treatment fluid may be prepared online or at the point of use, e.g., before and/or during the treatment. Here, purified water is typically mixed with a concentrate to prepare the treatment fluid online. To purify the water, a filter may be used. It is possible for the filter to become damaged. A need exists accordingly to provide a way to determine when the filter has become damaged, so that any potential harm to the patient resulting from the damaged filter may be avoided.

<CIT> discloses a method of performing a peritoneal dialysis treatment that includes connecting a disposable unit to a source of water, the disposable unit including at least a first container holding a sterile concentrate containing an osmotic agent, a second container holding a sterile concentrate containing electrolytes, an empty sterile mixing container, and a tubing set with a pre-attached peritoneal fill/drain line. The method further includes receiving a prescription command by a controller, indicating at least the fill volume and desired final concentration of the osmotic agent to be used for a current fill cycle under said treatment, and using the controller, pumping a quantity of the concentrated osmotic agent that is at least sufficient to achieve the desired final concentration into the mixing container. The contents of the mixing container are mixed, further diluted or concentrated, and then flowed to a patient.

<CIT> discloses dialysis systems comprising actuators that cooperate to perform dialysis functions and sensors that cooperate to monitor dialysis functions. According to one aspect, such a hemodialysis system comprises a user interface model layer, a therapy layer, below the user interface model layer, and a machine layer below the therapy layer. The user interface model layer is configured to manage the state of a graphical user interface and receive inputs from a graphical user interface. The therapy layer is configured to run state machines that generate therapy commands based at least in part on the inputs from the graphical user interface. The machine layer is configured to provide commands for the actuators based on the therapy commands.

The examples described herein disclose automated systems and methods applicable, for example, to fluid delivery for: peritoneal dialysis ("PD"), plasmapheresis, hemodialysis ("HD"), hemofiltration ("HF") hemodiafiltration ("HDF"), continuous renal replacement therapy ("CRRT"), apheresis, autotransfusion, hemofiltration for sepsis, and extracorporeal membrane oxygenation ("ECMO") treatments. The systems and methods described herein are applicable to any medical fluid delivery system in which the treatment fluid may be made online or at the point of use, e.g., just before and/or during treatment. These modalities may be referred to collectively or generally individually herein as medical fluid delivery system(s).

Moreover, each of the systems and methods described herein may be used with clinical or home-based treatments. For example, the present systems and methods may be employed in in-center PD, HD, HF or HDF machines, which run throughout the day. Alternatively, the present systems and methods may be used with home PD, HD, HF or HDF machines, which are operated generally at the patient's convenience.

In one embodiment, a peritoneal dialysis system is provided having point of use dialysis fluid production. The system includes a cycler and a water purifier. The cycler includes a control unit having at least one processor and at least one memory. The cycler may further include a wired or wireless transceiver for sending information to and receiving information from the water purifier. The water purifier may also include a control unit having at least one processor and at least one memory and a wired or wireless transceiver for sending information to and receiving information from the control unit of the cycler.

The cycler includes equipment programmed via its control unit to prepare fresh dialysis solution at the point of use, pump the freshly prepared dialysis fluid to a patient, allow the dialysis fluid to dwell within the patient, then pump used dialysis fluid to a drain. The cycler in one embodiment includes a heater under control of the control unit for heating the dialysis fluid as it is being mixed in one embodiment. The heater may for example be located at the top of a housing of the cycler, e.g., beneath a heating lid.

The cycler (and the water purifier in one embodiment) operates with a disposable set. The disposable set in one embodiment includes a disposable pumping cassette, which may include a planar rigid plastic piece covered on one or both sides by a flexible membrane, forming fluid pumping and valving chambers. The fluid pump chambers may operate with pneumatic pump chambers of the cycler, while fluid valve chambers operate with the pneumatic valve chambers of the cycler.

The disposable set may include (i) a patient line that extends from the cassette to a patient line connector, (ii) a drain line that extends from the cassette to a drain line connector (which may in turn connect removeably to the water purifier), (iii) a heater/mixing line that extends from the pumping cassette to a heater/mixing bag of the present disclosure, (iv) an upstream water line segment that extends from the water purifier to a water accumulator and a downstream water line segment that extends from the water accumulator to the cassette, (v) a last bag or sample line that extends from the cassette to a premixed last fill bag of dialysis fluid or to a sample bag or other sample collecting container, (vi) a first, e.g., glucose, concentrate line extending from the cassette to a first, e.g., glucose, concentrate container, and/or (vii) a second, e.g., buffer, concentrate line that extends from the cassette to a second, e.g., buffer, concentrate container.

In an embodiment, the upstream water line segment includes one or more sterilizing grade filter that further filters water exiting the water purifier to ensure that the water is made suitable for a peritoneal dialysis treatment ("WFPD") in case the water purifier itself is not able to do so. Redundant sterilizing grade filters are provided in an embodiment in case one of the filters fails. An integrity test is performed to ensure that at least the downstream filter is intact and functioning properly prior to each treatment in one embodiment.

The upstream water line segment in one embodiment includes a first portion extending from the water purifier to the upstream sterilizing grade filter, a second portion extending from the upstream sterilizing grade filter to the downstream sterilizing grade filter, and a third portion extending from the downstream sterilizing grade filter to one leg of a Y-connector (or T-connector, or the like). A common leg of the Y-connector leads to and from the water accumulator. A third leg of the Y-connector connects to a downstream water line segment, which runs from the Y-connector to a port of the disposable cassette.

The Y-connector is advantageous for the integrity test mentioned above, which is performed on at least one of the sterilizing grade filters. The integrity test in one embodiment applies a negative pressure to the sterilizing grade filter. The Y-connector provides a passage for the negative pressure to reach the filter, wherein the passage bypasses and does not require the water accumulator. The water accumulator may seal closed under negative pressure, such that a passage that included the interior of the water accumulator would be prone to becoming blocked. The legs of Y-connector not extending to the water accumulator allow a clear passage for negative pressure to be applied by the pumping chambers of the disposable set to the sterilizing grade filter even if the water accumulator has collapsed closed under the negative pressure.

The integrity test is in one embodiment a pressure decay test in which one or more hydrophilic cleaning membrane of the filter is first wetted. Wetting the membrane prevents air from passing through the membrane if the membrane is intact. Next, a preset negative pressure is applied to the filter, wherein the pneumatic pathway leading to the filter is closed. If the membrane is intact and wetted properly, the negative pressure in the pneumatic pathway leading to the filter will hold, at least so that a measured pressure decay rate level is below a predetermined pressure decay rate setpoint. But if one or more membrane of the sterilizing grade filter has been compromised, then the negative pressure will pull air in through the compromised membrane, relieving the negative pressure at a measured rate above a predetermined pressure decay rate setpoint. When this occurs, the control unit of the cycler causes its user interface to alarm and in one embodiment provide an audio, visual or audiovisual message informing the patient or caregiver that the filter is likely compromised and instructing that the current disposable set be replaced with a new set.

It should be appreciated from above that a source of air to the one or more membrane of the sterilizing grade filter is needed to perform the integrity test. In one embodiment, the filter is provided with one or more hydrophobic vent that allows air but not liquid to pass though the vent. The vent(s) is(are) configured to prevent any particulates or contaminants in the air from entering the filter. In another embodiment, the hydrophobic vent is provided instead in a second Y-connector, T-connector or branch stemming from the upstream water line segment upstream of the sterilizing grade filter, e.g., in the second portion of the upstream water line segment located between the upstream and downstream sterilizing grade filters. In this alternative embodiment, the filters do not need to provide or be fitted with one or more hydrophobic vent.

The pressure decay test just described is a first integrity test. In an alternative embodiment, the control unit of the cycler and/or the control unit of the water purifier alternatively or additionally performs a second integrity test using the water purifier to interrogate the sterilizing grade filters. Here, the control unit of the cycler and/or the water purifier is configured to examine the ratio of purified water pressure to flow rate (or flow rate to pressure) to inspect the integrity of the sterilizing grade filters. The control unit of the water purifier may have the capability to monitor the ratio over an extended period and to detect changes in performance of the sterile sterilizing filters, compensating with greater or lower pressure and alerting the user as needed. The control unit of the water purifier may report results to the control unit of the cycler, which notifies the patient of any problem. In one implementation, the water purifier maintains a flow rate through the sterilizing grade filters. In doing so, the water purifier compensates (raises or lowers) the pressure at which purified water is delivered to maintain the constant flow rate. Should one or both filters be compromised or should a leak occur in the purified water pathway, the preset flow rate will be achieved at a lower pressure, which the water purifier is configured to measure. Conversely, should one or both filters become partially blocked for whatever reason (e.g., due to bioburden), the preset flow rate will be achieved at a higher pressure, which the water purifier is configured to measure. In either situation, by monitoring the purified water flow rate to pressure relatively, and comparing same to predetermined limits set in the control unit of the water purifier or the cycler, an undesirable sterilizing condition will be detected and alerted to the patient or caregiver, instructing same to replace the currently installed disposable set with a new set having new sterilizing grade filters.

According to a first aspect of the present invention, there is provided a dialysis system that includes: a source of water purified; a source of concentrate for mixing with water from the water source; a disposable set including a pumping portion, a water line in fluid communication with the source of water and the pumping portion, the water line including a filter for filtering the water, a concentrate line in fluid communication with the concentrate source and the pumping portion; and a medical fluid delivery machine including a pump actuator operable with the pumping portion of the disposable set, a pressure sensor, and a control unit configured to cause (i) a membrane of the filter to be wetted, (ii) the pump actuator to remove at least some of the water from the filter, (iii) a portion of the water line leading from the pumping portion to the filter to be pressurized, (iv) the pressure sensor to sense pressure in the pressurized portion of the water line, and (v) an analysis of the sensed pressure to be performed to evaluate the integrity of the filter.

In a first embodiment of the dialysis system of the first aspect of the present invention, the control unit is configured to cause the pump actuator to pressurize the portion of the water line leading from the pumping portion to the filter.

In a second embodiment of the dialysis system of the first aspect of the present invention, which may also be combined with the first embodiment, the portion of the water line leading from the pumping portion to the filter is pressurized under negative pressure.

In a third embodiment of the dialysis system of the first aspect of the present invention, which may also be combined with the first or second embodiment, the pump actuator is a pneumatic pump actuator, the pumping portion of the disposable cassette includes a flexible pumping sheet, and wherein pressurizing the portion of the water line includes pneumatically moving the flexible pumping sheet. The dialysis system in this embodiment may include at least one of a positive or negative source of pressurized air operable with a pneumatic side of the flexible pumping sheet, and wherein the pressure sensor is located between the source of pressurized air and the pneumatic side of the flexible pumping sheet.

In a fourth embodiment of the dialysis system of the first aspect of the present invention, which may also be combined with any one of the first to third embodiments, the pumping portion of the disposable cassette includes a portion of the water line extending to operate with the peristaltic pump actuator, and wherein the pressure sensor is positioned and arranged to operate with a portion of the tube leading from the peristaltic pump actuator to the filter. In this embodiment, the peristaltic pump actuator may be configured to pressurize the water line leading from the pumping portion to the filter under negative pressure.

In a fifth embodiment of the dialysis system of the first aspect of the present invention, which may also be combined with any one of the first to fourth embodiments, the source of water includes a water purifier, and wherein a pump of the water purifier is caused to wet the membrane of the filter. The water purifier in this embodiment may include a control unit, and wherein the control unit of the medical fluid delivery machine communicates with the control unit of the water purifier to command the pump of the water purifier to wet the membrane of the filter.

In a sixth embodiment of the dialysis system of the first aspect of the present invention, which may also be combined with any one of the first to fifth embodiments, the control unit causes the pump actuator of the medical fluid delivery machine to wet the membrane of the filter.

In a seventh embodiment of the dialysis system of the first aspect of the present invention, which may also be combined with any one of the first to sixth embodiments, wetting the membrane of the filter includes causing water to be pumped across the membrane at least one time.

In an eighth embodiment, the dialysis system of the first aspect of the present invention further includes: a water accumulator in fluid communication with the water line via a connection that enables fluid communication between the pumping portion and the filter even if fluid communication with the water accumulator is occluded; and wherein the pump actuator is operable with the pumping portion of the disposable set to apply a negative pressure to the filter to evaluate the integrity of the filter via an output from the pressure sensor even if the water accumulator is occluded due to the negative pressure.

In a ninth embodiment of the dialysis system of the first aspect of the present invention, which may be combined with the eighth embodiment, the pump actuator is operable with the pumping portion of the disposable set to apply the negative pneumatic pressure to the filter to evaluate the integrity of the filter even if the water accumulator is occluded due to the negative pneumatic pressure.

In a tenth embodiment of the dialysis system of the first aspect of the present invention, which may be combined with the eighth and/or ninth embodiment, the disposable set further includes a drain line, and wherein the pump actuator is operable with the pumping portion to remove water from the filter via the drain line prior to applying the negative pressure to the filter to evaluate the integrity of the filter. In this embodiment, the source of water may include a water purifier, and wherein the water removed form the filter to drain is supplied to the filter from the water purifier. In addition, the filter may be a first filter, and the system may include a second filter located in the water line upstream from the first filter, wherein the water removed from the first filter to drain is delivered through the second filter to the first filter.

In light of the present disclosure and the above aspects, it is therefore an advantage of the present disclosure to provide an improved medical fluid delivery system.

It is another advantage of the present disclosure to provide an improved medical fluid delivery system that prepares treatment fluid online or at the point of use.

It is a further advantage of the present disclosure to provide an improved mixing structure and methodology for a medical fluid delivery system that prepares treatment fluid online or at the point of use.

It is yet another advantage of the present disclosure to provide an improved apparatus, system and method for testing the integrity of sterilizing grade filters used to prepare injectable grade medical solutions online.

It is a further advantage of the present disclosure to provide a second integrity test to evaluate the sterilizing grade filters in a different way to achieve different results that may be cross-meshed with the results of the first integrity test.

The advantages discussed herein may be found in one, or some, and perhaps not all of the embodiments disclosed herein. Additional features and advantages are described herein, and will be apparent from, the following Detailed Description and the figures.

The examples described herein are applicable to any medical fluid therapy system that delivers a medical fluid that may be mixed at the point of use, prior to and/or during treatment, such as dialysis fluid, substitution fluid, or an intravenous drug. The examples are particularly well suited for kidney failure therapies, such as all forms of peritoneal dialysis ("PD"), hemodialysis ("HD"), hemofiltration ("HF"), hemodiafiltration ("HDF") and continuous renal replacement therapies ("CRRT"), referred to herein collectively or generally individually as renal failure therapy. Moreover, the machines described herein may be used in clinical or home settings. For example, the machines and associated methods may be employed in an in-center PD or HD machine, which runs virtually continuously throughout the day. Alternatively, the machine and methods may be used in a home PD or HD machine, which can for example be run at night while the patient is sleeping. The machines and methods discussed herein are also applicable to medical delivery applications. The following examples will be described in the setting of a peritoneal dialysis system having point of use dialysis fluid production but may instead be used to make point of use treatment fluid for any of the above modalities.

Referring now to the drawings and in particular to <FIG>, one embodiment of a peritoneal dialysis system having point of use dialysis fluid production of the present disclosure is illustrated by system <NUM>. System <NUM> includes a medical fluid delivery machine or cycler <NUM> and a water purifier <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 are provided with updated programming to perform and use the point of use dialysis fluid produced according to system <NUM>. To this end, cycler <NUM> includes a control unit <NUM> having at least one processor and at least one memory. Control unit <NUM> further incudes a wired or wireless transceiver for sending information to and receiving information from a water purifier <NUM>. Water purifier <NUM> also includes a control unit <NUM> having at least one processor and at least one memory. Control unit <NUM> further incudes 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 <NUM> includes a drain line <NUM> leading to a drain <NUM>, which can be a house drain or a 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 each under control of control unit <NUM>, or a single pump creating both positive and negative pressure under control of control unit <NUM>, to provide 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 pneumatic solenoid 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 (ix) an occluder <NUM> under control of control unit <NUM> for closing the patient and drain lines in alarm and other situations.

In one 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 or tray, 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>. Control unit <NUM> in an embodiment includes a video controller, which may have its own processing and memory for interacting with primary control processing and memory of control unit <NUM>. User interface <NUM> includes a video monitor <NUM>, which may operate with a touch screen overlay placed onto video monitor <NUM> for inputting commands via user interface <NUM> into control unit <NUM>. User interface <NUM> may also include one or more electromechanical input device, such as a membrane switch or other button. Control unit <NUM> may further include an audio controller for playing sound files, such as voice activation commands, at one or more speaker <NUM>.

Water purifier <NUM> in the illustrated embodiment also includes a user interface <NUM>. Control unit <NUM> of water purifier <NUM> in an embodiment includes a video controller, which may have its own processing and memory for interacting with primary control processing and memory of control unit <NUM>. User interface <NUM> includes a video monitor <NUM>, which may likewise operate with a touch screen overlay placed onto video monitor <NUM> for inputting commands into control unit <NUM>. User interface <NUM> may also include one or more electromechanical input device, such as a membrane switch or other button. Control unit <NUM> may further include an audio controller for playing sound files, such as alarm or alert sounds, at one or more speaker <NUM> of water purifier <NUM>.

Referring additionally to <FIG>, one embodiment of disposable set <NUM> is illustrated. Disposable set <NUM> is also illustrated in <FIG>, mated to cycler <NUM> to move fluid within the disposable set <NUM>, e.g., to mix dialysis fluid as discussed herein. Disposable 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 sheet <NUM>. Flexible sheet <NUM> 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>.

<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> connects removeably to a drain connector <NUM> of water purifier <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 bag <NUM>. Disposable set <NUM> includes an upstream water line segment 64a that extends to a water inlet leg <NUM> of a Y-connector <NUM> (or T-connector, or the like) located just upstream of water accumulator <NUM>. Y-connector <NUM> connects to water accumulator <NUM> via leg <NUM>. A downstream water line segment 64b extends from a water outlet leg <NUM> of Y-connector <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"). To ensure WFPD, however, a sterilizing grade filter 100a is placed upstream from a downstream sterilizing grade filter 100b, respectively. Filters 100a and 100b may be placed in water line segment 64a upstream of water accumulator <NUM>. Sterilizing grade filters 100a and 100b may be pass-through filters that do not have a reject line. Pore sizes for the hydrophilic membranes of filters 100a and 100b may, for example, be less than a micron, such as <NUM> or <NUM> micron. Suitable sterilizing grade filters 100a and 100b may be provided by the assignee of the present disclosure. In an embodiment, only one of upstream or downstream sterilizing grade filter 100a and 100b is needed to produce WFPD, nevertheless, two sterilizing grade filters 100a and 100b are provided in the illustrated embodiment for redundancy in case one fails. Sterilizing grade filters 100a and 100b are discussed in detail below.

<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 bag <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 and verified, 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 and Y-connector <NUM> 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 Y-connector <NUM> (alternatively), for connector <NUM> of heater/mixing bag or container <NUM> and/or for concentrate connectors 80a, 80b, 82a, 82b 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, such as heater/mixing bag or container <NUM> discussed below, may be made of PVC. The materials for any of the above components may be changed over time.

Control unit <NUM> may be programmed to cause cycler <NUM> to perform one or more mixing action to help mix dialysis fluid properly and homogeneously for treatment. For example, any of fluid pump chambers <NUM> may be caused to withdraw into the pump chambers some amount of mixed fluid (e.g., made from one or both first and second concentrates 84a, 84b and WFPD) from heater/mixing bag <NUM> and send such mixture back to heater/mixing bag <NUM> and repeat this procedure multiple times (described herein as a mixing sequence or "waffling"). In particular, to perform a mixing sequence, control unit <NUM> in an embodiment causes cycler <NUM> to close all fluid valve chambers <NUM> at cassette <NUM> except for the fluid valve chamber <NUM> to heater/mixing line <NUM> and heater/mixing bag <NUM>. Fluid pump chambers <NUM> are stroked sequentially and repeatedly (i) pulling a possibly unmixed fluid combination of WFPD and concentrates from heater/mixing bag <NUM> into the pump chambers, followed by (ii) pushing the mixed WFPD and concentrates from the pump chambers back to heater/mixing bag <NUM> and (iii) repeating (i) and (ii) at least one time. Control unit <NUM> may be programmed to stroke fluid pump chambers <NUM> together so that they both pull and push at the same time, or alternatingly so that one pump chamber <NUM> pulls from heater/mixing bag <NUM>, while the other pump chamber <NUM> pushes to heater/mixing bag <NUM>, creating turbulence in heater/mixing line <NUM>.

Providing heater/mixing container or bag <NUM> with cassette <NUM> via heater/mixing line <NUM> enables the WFPD from accumulator <NUM> and concentrates from first and second concentrate containers 84a and 84b to be at least partially mixed prior to entering container or bag <NUM>. Even if cassette <NUM> is not provided, the WFPD and at least one concentrate will mix partially in heater/mixing line <NUM> prior to reaching the container or bag.

Referring now to <FIG>, sterilizing grade filters 100a and 100b are illustrated in more detail. Sterilizing grade filters 100a and 100b may, for example, be Pall IV-<NUM> or GVS Speedflow filters, or be filters provided by the assignee of the present disclosure. Filters 100a and 100b include a housing <NUM>, which may be made of any medical grade polymer, such as any of the materials listed above. Housing <NUM> includes or defines a filter inlet <NUM> and a filter outlet <NUM>. Filter inlet <NUM> of upstream sterilizing grade filter 100a is connected sealingly, e.g., via a compression, hose barb, or luer connection, to the upstream-most section of upstream water line segment 64a, while filter outlet <NUM> of upstream sterilizing grade filter 100a is connected sealingly, e.g., via a compression, hose barb, or luer connection, to a section 64c (<FIG>) of upstream water line segment 64a located between filters 100a and 100b. Filter inlet <NUM> of downstream sterilizing grade filter 100b is connected sealingly, e.g., via a compression, hose barb, or luer connection, to section 64c (<FIG>) of upstream water line segment 64a, while filter outlet <NUM> of downstream sterilizing grade filter 100b is connected sealingly, e.g., via a compression, hose barb, or luer connection, to a downstream-most section of upstream water line segment 64a.

<FIG> also illustrate that housing <NUM> includes one or more hydrophobic filter or vent 108a to 108d. Hydrophobic materials are air passing but liquid, e.g., water, retaining, such that air may pass through vents 108a to 108d, but wherein the vents prevent liquid from entering into and flowing out of housing <NUM>. Vents 108a to 108d serve the purpose of allowing air to enter filters 100a and 100b and in doing so, removing particulates and contaminants from the air so that the entering air does not affect the liquid or water flowing through the filter 100a or 100b. Multiple vents 108a to 108d are advantageous because they provide multiple pathways for air in case one or more of vents 108a to 108d becomes wetted, which prevents air from passing across the hydrophobic vents.

<FIG> illustrates how water flows through the illustrated embodiment for filters 100a and 100b. Water enters though inlet <NUM> and flows along an inlet path <NUM>. Inlet path <NUM> splits into inlet branches 114a and 114b. Inlet branch 114a extends above a hydrophilic membrane 110a, while inlet branch 114b extends below a hydrophilic membrane 110b in the orientation of filter 100a, 100b in <FIG>. Hydrophilic materials are liquid passing and air retaining when wetted. Hydrophilic membranes 110a and 110b accordingly allow liquid to pass through, while not allowing air to pass through when wetted with liquid, thereby preventing air entering filters 100a and 100b from becoming entrained in the water traveling through the filters. Pore sizes for hydrophilic membranes 110a and 110b may again, for example, be less than a micron, such as <NUM> or <NUM> micron.

In the illustrated embodiment, hydrophilic membranes 110a and 110b are provided as part of a membrane housing <NUM>. Membrane housing <NUM> is sealed to hydrophilic membranes 110a and 110b, so that the only way into the inside of housing <NUM> is through the membranes. In this manner, when hydrophilic membranes 110a and 110b are wetted properly with a liquid, e.g., purified water, such that the membranes block air flow, no air may enter membrane housing <NUM> from the outside of the housing.

<FIG> illustrates that water filtered via hydrophilic membranes 110a and 110b leaves membrane housing <NUM> and exits outlet <NUM> of housing <NUM> via an outlet path <NUM>. Water exiting via outlet path <NUM> after being purified by water purifier <NUM> and further filtered via filter 100a, 100b is considered to be pure enough to be WFPD. Again, one filter 100a, 100b is typically enough to ensure WFPD quality, however, two filters 100a and 100b may be provided for redundancy.

In an alternative embodiment, hydrophobic filter or vent 108a to 108d may not be provided with filters 100a and 100b and be provided instead adjacent to the filters. Filters 100a and 100b in such a case, would still provide one or more hydrophilic membrane 110a, 110b, but not the hydrophobic vents.

Referring now to <FIG>, one set of components from system <NUM> for performing a filter integrity test of the present disclosure is illustrated. <FIG> illustrates a simplified version of medical fluid delivery machine or cycler <NUM> having housing <NUM> holding control unit <NUM>. Disposable cassette <NUM> is mounted operably to housing <NUM>. Disposable cassette <NUM> receives WFPD from water purifier <NUM> having control unit <NUM>, which communicates via wired or wireless communication (wireless shown) with control unit <NUM> of medical fluid delivery machine or cycler <NUM>. Purified water leaving water purifier exits via upstream water line segment 64a, though filters 100a and 100b, ensuring WFPD, and in normal operation fills water accumulator <NUM> via legs <NUM> and <NUM> of Y-connector <NUM> (or T-connector, or the like) and with an associated water line valve <NUM> (not illustrated in <FIG>) of cassette <NUM> closed, so that the WFPD backfills water accumulator <NUM>. When the water line valve <NUM> of cassette <NUM> is opened, WFPD may flow between legs <NUM> and <NUM> of Y-connector <NUM>, bypassing water accumulator <NUM>, such that purified water may flow back and forth between cassette <NUM> and water purifier <NUM> via upstream water line segment 64a and downstream water line segment 64b.

Components in <FIG> not illustrated in <FIG> include positive and negative pressure reservoirs <NUM> and <NUM>, respectively, located within medical fluid delivery machine or cycler <NUM>. Medical fluid delivery machine <NUM> is in one embodiment actuated pneumatically. Positive and negative pressure reservoirs <NUM> and <NUM> may be charged via one or more pneumatic pump (not illustrated), wherein positive tank <NUM> may hold, e.g., three to seven +psig air, while negative tank <NUM> may hold, e.g., one to six -psig air. Positive and negative pressure reservoirs <NUM> and <NUM> communicate via electrically actuated pneumatic solenoid valves <NUM> and <NUM>, respectively, located along pneumatic lines <NUM> with a pneumatic pump chamber <NUM> defined in or provided by housing <NUM> of machine <NUM>. Electrically actuated pneumatic solenoid valves <NUM> and <NUM> in an embodiment are closed when unenergized and opened upon being energized.

A pressure sensor <NUM> is located along pneumatic line <NUM>. The dashed lines extending from control unit <NUM>, solenoid valves <NUM> and <NUM> and pressure sensor <NUM> indicate that solenoid valves <NUM> and <NUM> and pressure sensor <NUM> may receive power and/or signals from control unit <NUM> and may send electrical or signal readings to control unit <NUM>. The dashed lines extending from control unit <NUM> and water pump <NUM> of water purifier <NUM> likewise indicate that control unit <NUM> may electrically control water pump <NUM> and receive electrical or signal feedback from water pump <NUM>.

<FIG> illustrates that disposable cassette <NUM> in one embodiment includes a flexible sheet <NUM> that covers fluid pump chambers <NUM> of the cassette. Flexible sheet <NUM> may also cover one or more fluid valve <NUM> (not illustrated in <FIG>) of disposable cassette <NUM>. To push fluid out of disposable cassette <NUM>, control unit <NUM> causes pneumatic solenoid valve <NUM> to open, enabling flexible sheet <NUM> at pump chamber <NUM> to see positive pressure, which pushes flexible sheet <NUM> towards the wall of fluid pump chamber <NUM>, and expels fluid from disposable cassette <NUM>, e.g., out downstream water line segment 64b. To pull fluid into disposable cassette <NUM>, control unit <NUM> causes pneumatic solenoid valve <NUM> to open, enabling flexible sheet <NUM> at pump chamber <NUM> to see negative pressure, which pulls flexible sheet <NUM> towards the wall of pneumatic pump chamber <NUM>, thereby pulling fluid into disposable cassette <NUM>, e.g., from downstream water line segment 64b.

In both the inlet (negative) and outlet (positive) strokes discussed above, pressure sensor <NUM> monitors the pressure in pneumatic line <NUM>. Due to the flexibility of sheet <NUM>, the pneumatic pressure sensed at pressure sensor <NUM> is the same as the fluid pressure located on the opposite side of the sheet. In this way, if the negative pneumatic pressure for pumping from the patient is controlled to be, e.g., -<NUM> psig, the fluid pressure exerted on the patient is likewise -<NUM> psig. If the positive pneumatic pressure for pumping to the patient is controlled to be, e.g., +<NUM> psig, the fluid pressure exerted on the patient is likewise +<NUM> psig.

Referring additionally to <FIG>, one embodiment of an integrity test procedure of the present disclosure is illustrated via method <NUM>. Method <NUM> is controlled in one embodiment via control unit <NUM> of machine or cycler <NUM>, which may as needed communicate with control unit <NUM> of water purifier <NUM>. At oval <NUM>, method <NUM> begins. Method <NUM> is a method for testing the integrity of sterilizing grade filters 100a and 100b, and in one embodiment downstream sterilizing grade filter 100b. As such, method <NUM> is performed in one embodiment prior to each treatment. In an alternative embodiment, to conserve time, method <NUM> may be performed while dialysis fluid is mixing and being heated in heater/mixing bag <NUM>. Here, if a compromised sterilizing grade filter 100b is detected, the mixing dialysis fluid may be discarded along with disposable set <NUM>. Further alternatively of additionally, if disposable set <NUM> is to be reused, method <NUM> may be performed after treatment, which would allow set <NUM> to be changed if needed prior to beginning the next treatment.

When method <NUM> is performed prior to treatment, disposable set <NUM> is initially dry. As discussed above in connection with <FIG>, to close off membrane housing <NUM> from outside air, hydrophilic membranes 110a and 110b need to be wetted, as illustrated at block <NUM>. To wet membranes 110a and 110b, machine control unit <NUM> in one embodiment communicates with purifier control unit <NUM>, prompting control unit <NUM> to cause pump <NUM> to pump an amount of purified water from water purifier <NUM> sufficient to fully wet the membranes 110a and 110b of downstream sterilizing grade filter 100b. It should be appreciated that doing so also wets the membranes 110a and 110b of upstream sterilizing grade filter 100a. Water may be pumped back and forth across membranes 110a and 110b one or more time to fully wet the membranes.

At block <NUM>, control unit <NUM> sequences pneumatic valves <NUM> and <NUM> and the water and drain fluid valves <NUM> of disposable cassette <NUM> in an attempt to pull water that has been pushed in wetting step <NUM> passed downstream sterilizing grade filter 100b into cassette <NUM> and to push the fluid out of the disposable cassette to drain via drain line <NUM>. It should be appreciated that the drained water is allowed to bypass water accumulator <NUM> via legs <NUM> and <NUM> of Y-connector <NUM>. At the end of the drain sequence of block <NUM>, it is desirable for a clear pneumatic path to exist between pump chamber(s) <NUM> of disposable cassette <NUM> and downstream sterilizing grade filter 100b.

Because sterilizing grade filter 100b is vented via hydrophobic vents 108a to 108d, when cycler <NUM> pulls a vacuum on water line segments 64a and 64b, the vacuum will pull air in through the vents to pull the purified water back through water line segments 64a and 64b to cassette <NUM>. The purified water will pass through hydrophilic membranes 110a and 110b so long as the vacuum is applied. Once the water is evacuated from filter 100b, air will try to pass through hydrophilic membranes 110a and 110b. If membranes 110a and 110b are wetted out with water, air will not be allowed to pass unless the bubble point of membranes 110a and 110b is reached, which should never happen with intact membranes because the bubble point is selected to be sufficiently high. If a hole has developed in either membrane 110a or 110b, air will continue to displace purified water in upstream water line segment 64a towards Y-connector <NUM>. It is worth noting that if filter 100b closest to accumulator bag <NUM> does not have a compromised hydrophilic membrane 110a or 110b, the pressure decay test will pass even if there is a hole in either hydrophilic membrane 110a or 110b of upstream filter 100a (closest to the water purifier <NUM>) because any air that enters through hydrophobic vents 108a to 108d of upstream filter 100a will be trapped at the intact hydrophilic membranes 110a and 110b of downstream filter 100b, and the vacuum pulled via cycler <NUM> will be maintained.

At block <NUM>, control unit <NUM> causes a pressure decay test on the membranes 110a and 110b of downstream sterilizing grade filter 100b to be initiated. To initiate the pressure decay test, control unit <NUM> closes (or keeps closed) positive pneumatic valve <NUM> and opens negative pneumatic valve <NUM> to pull a vacuum on flexible sheet <NUM> and correspondingly on the air in downstream water line segment 64b, Y-connector <NUM>, upstream water line segment 64a, and the inside of membrane housing <NUM> holding the wetted hydrophilic membranes 110a and 110b of downstream filter 100b. In an embodiment, flexible sheet <NUM> is pulled only part of the way towards the wall of pneumatic pump chamber <NUM>. Although not illustrated, it is contemplated to place one or more pneumatic regulator, e.g., a variable orifice pneumatic regulator, in pneumatic line <NUM> upstream of pressure sensor <NUM>. The pneumatic regulator allows control unit <NUM> to set a desired positive or negative pressure in pneumatic line <NUM> between the regulator and pneumatic pump chamber <NUM>. In this manner, the negative pressure for the pressure decay test of block <NUM> may be set at a desired negative pressure, e.g. -<NUM> psig. , which is confirmed via pressure sensor <NUM>.

After the desired negative pressure has been set, control unit <NUM> at diamond <NUM> monitors readings from pressure sensor <NUM> to see if the negative pressure holds. That is, if wetted hydrophilic membranes 110a and 110b are in tact, then no or very little air may enter membrane housing <NUM> via hydrophobic filter or vent 108a to 108d. If, however, one or more wetted hydrophilic membrane 110a and 110b is not in tact, e.g., if there is a tear in one of the membranes, then air will enter into the otherwise closed membrane housing <NUM> via hydrophobic filter or vent 108a to 108d. The additional air will relieve the vacuum on the fluid side of flexible sheet <NUM>. Flexible sheet <NUM> will move responsively to equalize the negative pressure on both sides. Since the negative pressure is temporarily higher on the pneumatic side of flexible sheet <NUM>, the sheet will move towards the wall of pneumatic pump chamber <NUM>, thereby relieving negative pressure in pneumatic line <NUM>, which is sensed by pressure sensor <NUM> and signaled to control unit <NUM>.

At diamond <NUM>, control unit <NUM> looks at pressure signals from pressure sensor <NUM> over a predetermined amount of time for the pressure decay test. The predetermined amount of time may be, for example, on the order of minutes, e.g., one to five minutes or seconds, e.g., <NUM> to <NUM> seconds. If the negative pressure loss or decay amounts to more than a preset threshold, then control unit <NUM> determines that there is a leaking membrane 110a and/or 110b in downstream sterilizing grade filter 100b. The leakage may be programmed into control unit <NUM> as a rate of decay expressed in units of pressure over time. Here, leakage rate above a rate threshold triggers a compromised hydrophilic membrane determination.

In one example, water purifier <NUM> delivers a small volume of purified water through each filter 110a and 100b to wet out each hydrophilic membrane 110a and 110b as discussed above. A product water valve at purifier <NUM> is closed at water purifier <NUM> and cycler <NUM> begins to evacuate the water and air from water lines 64a and 64b until a vacuum pressure stabilizes at <NUM> kPa, which is enough to collapse water accumulator <NUM> (desirable for the pressure decay test) but not the tubing of water line segments 64a and 64b. Cycler <NUM> then stops pulling the vacuum and begins to monitor the negative pressure in water lines 64a and 64b, which may last for up to twenty seconds. During this time, if the pressure drop across any two second window is Δ <NUM> kPa/sec * <NUM> sec = Δ <NUM> kPa or more, then cycler <NUM> assumes and error in hydrophilic membrane 110a or 110b of downstream filter 100b and reacts as described herein.

It all should be appreciated that negative pressure supplied during each of the steps associated with block <NUM>, block <NUM> and diamond <NUM> is able to reach filter 100b even if the negative pressure closes and occludes water accumulator <NUM>. Y-connector <NUM> allows accumulator <NUM> to be bypassed in such a case as described herein.

At block <NUM>, if control unit <NUM> determines that downstream sterilizing grade filter 100b is intact, then control unit <NUM> continues treatment. At block <NUM>, if control unit <NUM> determines that downstream sterilizing grade filter 100b is compromised, then control unit <NUM> discontinues treatment, alarms audibly, visually or audiovisually, and alerts the patient or caregiver to remove current disposable set <NUM> and to install a new set to continue treatment. At oval <NUM>, method <NUM> ends.

It should be appreciated that even if downstream sterilizing grade filter 100b is determined to be compromised, it is highly likely that upstream sterilizing grade filter 100a is still intact. So if for example the failed integrity test is performed after treatment, the treatment has nevertheless been performed in all probability using properly sterilized dialysis fluid.

<FIG> illustrates in phantom an alternative embodiment in which a connector <NUM> housing one or more hydrophobic filter or vent <NUM> is located between upstream and downstream sterilizing grade filters 100a and 100b at section 64c. Here, filters 100a and 100b do not need hydrophobic vents 108a to 108d. If one or more wetted hydrophilic membrane 110a and 110b of downstream sterilizing grade filter 100b is not in tact, e.g., if a tear exists in one of the membranes, then air will enter into the otherwise closed membrane housing <NUM> via hydrophobic vent <NUM>.

The pressure decay test just described is a first integrity test. In an alternative embodiment, control unit <NUM> of cycler <NUM> and/or control unit <NUM> of water purifier <NUM> alternatively or additionally performs a second integrity test using equipment <NUM>, <NUM> and <NUM> of water purifier <NUM> to interrogate sterilizing grade filters 100a and 100b. Here, control unit <NUM> of cycler <NUM> and/or control unit <NUM> of water purifier <NUM> is/are configured to examine the ratio of the pressure to flow rate (or flow rate to pressure) to inspect the integrity of the hydrophilic membranes 110a and 110b of both sterilizing grade filters 100a and 100b.

In various embodiments, control unit <NUM> of the water purifier <NUM> has the capability to monitor the ratio over an extended period and to detect changes in performance of hydrophilic membranes 110a and 110b of sterilizing grade filters 100a and 100b, compensating with greater or lower pressure and alerting the user as needed. Control unit <NUM> of water purifier <NUM> may (i) report results to control unit <NUM> of the cycler <NUM>, which notifies the patient of any problem via user interface <NUM> or (ii) report results at user interface <NUM> of water purifier <NUM> for notification.

In one implementation, water purifier <NUM> maintains a purified water flow rate through the sterilizing grade filters 100a and 100b using an electronic flow meter <NUM> outputting to control unit <NUM>. In doing so, water purifier <NUM> compensates (raises or lowers) the pressure at which purified water is delivered to maintain the constant flow rate set in control unit <NUM> using an electronic pressure regulator <NUM> under command of control unit <NUM> and an electronic pressure gauge outputting to control unit <NUM>. Should one or both filters 100a and 100b be compromised or should a leak occur in the purified water line segments 64a and 64b, the preset flow rate measured at flow meter <NUM> will be achieved at a lower pressure, which the water purifier <NUM> controls via regulator <NUM> and measures via gauge <NUM>. Conversely, should one or both filters 100a and 100b become partially blocked for whatever reason (e.g., due to bioburden), the preset flow rate measured at flow meter <NUM> will be achieved at a higher pressure, which water purifier <NUM> controls via regulator <NUM> and measures via gauge <NUM>. In either situation, by monitoring the flow rate to pressure relatively at control unit <NUM>, and comparing same to predetermined limits set in the control unit of water purifier <NUM> or that of cycler <NUM>, an undesirable sterilizing condition is detected and alerted to the patient or caregiver, instructing same to replace the currently installed disposable set <NUM> with a new set having new sterilizing grade filters 100a and 100b.

As discussed, the alternative flow rate/pressure integrity test just described may be used alternatively or additionally to the pressure decay test described at method <NUM> of <FIG>. When used additionally, it should be appreciated that sterilizing grade filters 100a and 100b are tested from both downstream (pressure decay) and upstream (flow rate/pressure) directions. The pressure decay and flow rate/pressure tests also compliment each other in that the pressure decay test pinpoints downstream filter 100b as the culprit, while the flow rate/pressure test determines if either filter 100a and 100b fails. Thus if the flow rate/pressure test fails but the pressure decay test passes, then it may be assumed that upstream filter 100a is the culprit.

Claim 1:
A dialysis system (<NUM>) comprising:
a source of water purified (<NUM>, <NUM>, <NUM>);
a source of concentrate (84a, 84b) for mixing with water from the water source;
a disposable set (<NUM>, <NUM>) including
a pumping portion (<NUM>),
a water line (64a) in fluid communication with the source of water and the pumping portion, the water line including a filter (100a, 100b) for filtering the water,
a concentrate line (<NUM>, <NUM>) in fluid communication with the concentrate source and the pumping portion; and
a medical fluid delivery machine (<NUM>) including
a pump actuator operable with the pumping portion of the disposable set,
a pressure sensor (<NUM>), and
a control unit (<NUM>),
characterized in that the control unit (<NUM>) is configured to cause (i) a membrane (110a, 110b) of the filter to be wetted, (ii) the pump actuator to remove at least some of the water from the filter, (iii) a portion of the water line leading from the pumping portion to the filter to be pressurized, (iv) the pressure sensor to sense pressure in the pressurized portion of the water line, and (v) an analysis of the sensed pressure to be performed to evaluate the integrity of the filter.