US20230090483A1 - Dialysis system and apparatus with inline inductive fluid heating - Google Patents

Abstract

An inductive inline dialysis fluid heater is disclosed. In an example, a dialysis fluid heater includes a cylindrical tube including an inner diameter that is between 4.00 millimeters (“mm”) and 12.7 mm. The dialysis fluid heater also includes a susceptor located within the cylindrical tube and an inductive coil extending around the cylindrical tube in a non-contacting arrangement. The dialysis fluid heater further includes power electronics in electrical communication with the inductive coil and configured to supply an electrical current to the inductive coil, causing the susceptor to heat.

Description

TECHNICAL FIELD
• The present disclosure relates generally to medical fluid therapies and more particularly to medical fluid therapy systems that are capable of producing medical fluid at the point of use.
BACKGROUND
• Certain medical fluid therapies employ presterilized bags of treatment fluid. For example, peritoneal dialysis is typically performed in a patient's home. There are different types of peritoneal dialysis, including continuous ambulatory peritoneal dialysis (“CAPD”) and automated peritoneal dialysis (“APD”). CAPD is a manual treatment in which the patient typically drains used dialysis fluid from the patient's peritoneal cavity and then causes fresh dialysis fluid to refill the peritoneal cavity. The fresh dialysis fluid is left to dwell for a period of time to remove waste, toxins and excess water into the dialysis fluid, after which the used fluid is drained to begin a new cycle.
• APD is performed by a machine, which is sometimes referred to as a cycler because it performs the same cycles described above for CAPD. APD is typically performed at night, while the patient sleeps, and while the patient's indwelling peritoneal catheter is connected to a patient line extending to the APD machine. As with CAPD, if the patient at the start of treatment is full with used peritoneal dialysis (“PD”) fluid, the APD machine initially drains the used fluid to a dedicated drain bag or to a house drain. Next, the APD machine fills the patient with fresh peritoneal dialysis fluid, which is left to dwell for a period of time to remove waste, toxins and excess water into the dialysis fluid. The APD machine repeats the above cycle until a prescribed amount of fresh peritoneal dialysis fluid has been delivered to the patient.
• CAPD and APD typically use multiple bags per treatment, for example, two to four bags. CAPD may be performed multiple times during the day, while nighttime APD may be accompanied by a midday manual exchange. The number of bags per day multiplied by the number of days between treatment fluid deliveries results in the patient having to store boxes upon boxes of solution in their home. In many instances, a wall of a room is dedicated to storing PD solution and supplies.
• Another way that medical fluid therapy fluids or solutions are prepared is to do so at the place of treatment, which is sometimes termed “online generation”. Hemodialysis (“HD”), which cleans the patient's blood as opposed to using the patient's peritoneal cavity, typically makes HD dialysis fluid online. To do so, water first has to be purified to a level that is safe for treatment. Once HD concentrates have been added to the purified water, the resulting HD dialysis fluid is passed through a dialyzer, which also receives the patient's blood, to exchange waste, toxins and excess patient water across the dialyzer membranes and into the HD dialysis fluid. HD treatments are most often performed in a dialysis center, in which a large batch of highly purified water may be made for multiple HD dialysis machines located within the center.
• In the center, noisy water purification equipment, such as pumps and reverse osmosis (“RO”) units, can be located in a different room or otherwise away from the patient area. Also, because water purification may be centralized for multiple machines, equipment cost is reduced. Attempts have been made to make water purification units for home therapy systems, such as home dialysis systems. Some of the attempts have included a multitude of different purification technologies, such as carbon pretreatment packs, RO filtration, electrodeionization (“EDI”), resin beds, ultraviolet (“UV”) radiation, ultrafiltration and others. While the combination of such technologies may yield ultrapure water, the resulting systems are complicated and expensive.
• A need exists accordingly for an improved dialysis system that reduces the amount of space and disposable waste associated with premade dialysis fluid and that improves the current issues associated with water purification devices and online dialysis fluid generation.
SUMMARY
• The devices, systems and methods of the present disclosure attempt to remedy the above-described problems. In one embodiment, the system provides a non-invasive measurement of volume and flow, which allows for any type of dialysis fluid pump to be used. From a simplicity of disposable standpoint, the most desirable pump is a peristaltic pump, which simply requires a pumping tube to operate with a peristaltic pump actuator. Peristaltic pumps are known to be less accurate than other types of fluid pumps, such as membrane pumps, and to become less accurate over time as the peristaltic pump tubing degrades. The present system and method provide a rigid, vertically disposed clamshell holder that accepts a flexible, vertically disposed and sterilized container or bag for receiving fresh dialysis fluid, used dialysis fluid, saline, purified water and concentrates for mixing dialysis fluid, or other medical fluid.
• As whichever fluid fills the vertically disposed bag, the bag where the fluid is located conforms exactly (or near exactly) to the shape of the vertically disposed clamshell holder. The filling fluid also increases pressure within the sterilized bag. The control unit uses a relationship between pressure and head height to calculate fluid volume. With all other dimensions of the vertically disposed clamshell holder known except for the height of fluid within the bag, solving for the head height based on a measured pressure allows the volume of fluid in the bag at a given time to be calculated. Calculating a difference between head heights and dividing the difference by a time between pressure measurements allows a flowrate to be determined.
• In an embodiment, one or more pressure sensors are located at the bottom of the clamshell holder, e.g., is fixed within an opening or mounting structure formed in the lower portion of a panel of the clamshell holder. The pressure sensor may include a pressure pouch that is mounted to or into the panel of the clamshell holder, wherein the pressure pouch makes contact with the vertically disposed container or bag. The pressure pouch holds air or other pressure transmission medium that transfers the pressure due to medical fluid within the vertically disposed bag to a pressure transducer, such as a load cell, strain gauge, and/or compensated microelectromechanical systems (“MEMS”) pressure sensor. The pressure transducer outputs a signal indicative of the pressure and thus the head height of medical fluid within the bag to a microprocessor, which determines head height, multiplies the head height by the cross-sectional area of the clamshell holder to determine volume and divides the volume over a time delta to determine flowrate.
• In one embodiment, the system is configured not to completely fill the vertically disposed bag so that the bag does not apply pressure to the medical fluid located therein. Also, the top of the bag is not constrained by the clamshell holder so as not to pressurize the bag. Additionally, the bag and clamshell holder overlap so that the liquid filled cross-sectional area is defined by the known dimensions of the clamshell holder as opposed to the welds or seems of the container or bag.
• It is contemplated to install one or more liquid level sensors in or on one of the panels of the rigid clamshell holder to maintain a baseline level of medical fluid within the flexible bag. The baseline level of fluid serves multiple purposes. First, the bottom of the clamshell holder and thus the disinfected bag may be angled, rounded or otherwise changing in cross-section to help direct fluid to an inlet/outlet and so that the bag does not have to be formed with a flat bottom. The change in cross-section may cause the bag to not be perfectly aligned with the clamshell holder. Also, the contacting of the one or more pressure sensor with bottom of the bag may cause misalignment between the bag and the clamshell holder. In an embodiment, the liquid below baseline is not taken into account in the volume or baseline determination, such that each of the discrepancies just described existing below the baseline level may be discarded.
• The liquid level sensor may be, for example, a non-invasive capacitive sensor that senses the level of medical fluid within the flexible container or bag. The sensor outputs, for example, upon a patient fill or upon an effluent drain when the liquid level falls to the sensor level, such that the fill or drain may be discontinued until additional fresh or used dialysis fluid is introduced into the flexible bag. The establishment of a baseline level via sensor also ensures that a fill of fresh or used dialysis fluid into the flexible bag is commenced with the liquid level at or above the baseline level. In an embodiment, two or more level sensors are provided so that one or more upper warning level may be detected prior to reaching a level below which the current cycle needs to be interrupted. In other embodiments, the level of the medical fluid may instead be determined by measuring a water column head pressure.
• In an embodiment a delivery tube extends out of the bottom of the sterilized flexible bag. The delivery tube allows the different medical fluids to flow into and out of the bag. In an embodiment, the delivery tube is placed in selective communication with a pump, such as a peristaltic pump, which pumps medical fluid to or from flexible bag, e.g., through one or more valve. In an alternative embodiment, a low cost gravity fed system is provided that does not use a pump, but instead, under computerized valve control, allows fresh fluid to flow from a fresh fluid clamshell holder and flexible bag to the patient for treatment, and used fluid to flow from the patient, under computerized valve control, to a used fluid clamshell holder and flexible bag. The fresh and used fluid clamshell holders and flexible bags operate just as described above, except that they are one-way with fluid only flowing out or into the containers or bags. The fresh fluid clamshell and flexible bag allow monitoring of volume and flowrate of fresh dialysis fluid to the patient. The used fluid clamshell holder and flexible bag allow monitoring of volume and flowrate of used dialysis fluid removed from the patient. The difference between the two is the patient's ultrafiltration (“UF”) removal.
• In an embodiment, an inline medical fluid heater is located between the pump and the patient to heat the dialysis fluid to patient temperature, e.g., 37° C., prior to delivery to the patient. The inline heater may be an inductive heater in which the disposable component of the inductive heater is, like the pump, a single tube or a tube that is folded or provided with a fitting such that the tube reversesdirection 180 degrees. The tube, or each leg of the dual tube, is provided with a susceptor, which may be any medically safe material having the ability to absorb electromagnetic energy and convert the energy to heat. In an embodiment, the susceptor is made of a medically safe material that exhibits properties of an efficient susceptor, such as 400 series stainless steel, 18-0 magnetic stainless steel, titanium, and combinations and alloys thereof. The susceptor may have a smooth contour to limit its effect on pressure drop in the medical fluid, a changing countour, e.g., mesh or brillo pad, to increase surface area contact with the medical fluid, or a combination of both.
• The tubes including the susceptors are fitted within an inductive coil, which may be a conductive copper coil. The copper coil is provided as part of the dialysis machine and is covered by a plastic machine panel (or other material that is not heated by the energized coil) so that a user cannot accidently touch the coil. The inductive coil is connected electrically to power electronics, such as a resonant circuit and driver electronics. The driver electronics are placed under the control of a computerized control unit, which controls the driver electronics to cause power to be supplied to the driver electronics and the induction coil when needed, e.g., when fresh dialysis fluid is flowing to the patient and when feedback from one or more dialysis fluid temperature sensor indicates to the control unit that fluid heating is needed.
• In an embodiment, an upstream temperature sensor is housed with the machine and is located so as to sense the temperature of cool dialysis fluid upstream of the one or more susceptor. A downstream temperature sensor is housed with the machine and is located so as to sense the temperature of heated dialysis fluid downstream of the one or more susceptors and heading to the patient. The temperature sensors may be non-contact (e.g., thermopile) sensors, so that there is no invasive or direct fluid contact. The control unit may use the temperature sensor feedback and control power to the resonant circuit and inductive coil using on/off control, proportional-integral-derivative (“PID”) control, fuzzy logic control and combinations thereof. In an embodiment, the power supplied to the power electronics is around one kilowatt.
• The inductive system is safe for the user. The susceptors in an embodiment increase in temperature only a few degrees above the target temperature, e.g., 37° C., and are cooled immediately by the dialysis fluid. The temperatures of the tubes carrying the susceptors are not appreciably higher than the target temperature. The temperature sensors have been found to operate well when positioned more than 12.5 mm (one-half inch) from the tubes carrying the fluid to be sensed. Thus close and precise positioning of the disposable tubes with respect to the temperature sensors is not overly critical.
• The inductive, inline heating of the present disclosure is advantageous for at least one reason including: being non-invasive or non-contact, having a quick heating response time, operating with a low cost and space saving disposable, having a high power coupling resulting in efficient heating, requiring lower cost electronics, control and sensing, and heating accurately.
• Prior to delivering dialysis fluid to the patient, the disposable set, and most importantly the patient line, is primed so that air is not delivered to the patient and volumetric accuracy is not compromised. Existing priming methods typically involve many manual steps and impose a high cognitive load that may strain patients and make the therapy more error prone, potentially exposing patients to harm. The present system and method contemplate the provision of a patient line connector that, once connected to the patient's transfer set, self-primes and then opens to allow dialysis fluid to be delivered to and removed from the patient. The patient does not have to handle the connector during the priming operation in one embodiment.
• The connector in one embodiment includes a hydrophobic membrane that is normally sealed closed by a check valve. Under positive pressure during priming, the check valve opens, allowing the priming fluid, e.g., fresh dialysis fluid, to push air out of the patient line and out of the patient connector, through the hydrophobic membrane or vent. The hydrophobic membrane allows air from the patient line to pass through the membrane. Once there is no more air in the patient line, the hydrophobic membrane prevents the dialysis fluid or other priming liquid from passing through the membrane, such that pressure builds in the patient line.
• The end of the patient connector is originally sealed via a solid seal, which prevents air from entering the patient's transfer set and aids in forcing the air out through the hydrophobic vent. In one embodiment, the material and thickness of the solid seal are selected so that the seal ruptures open under the pressure that builds after all (or substantially all) of the patient line air has been vented through the hydrophobic membrane. Here, the seal may be provided with score lines or grooves of narrowed thickness so that the solid seal ruptures in a uniform and repeatable way. For example, the score lines may form and X or cross, which tends to rupture at the junction of the score lines and then tear along the score lines outwardly towards the cylindrical connector wall.
• In an alternative embodiment, a cutting member is provided, which is not moved while air is being purged from the hydrophobic member of the patient connector, but is moved after the air has been purged and upon the building of fluid pressure trapped in part by the hydrophobic membrane and the solid seal. The cutting member may be in the form of a cylindrical spike made of a resilient and low coefficient of friction material, such as teflon, which is confined to translate within the patient connector over a short distance that is enough to puncture and tear the solid seal. The puncture may occur along the outer rim of the solid seal and the tear may occur along the spike as it translates through the seal. In an embodiment, a portion of the seal remains attached to the patient connector so that the seal is not carried to an undesirable place and so that the seal does not inadvertently reseal the patient connector closed.
• In one implementation, which is used with either the punctured or cut solid seal embodiments described above, an outer housing of the patient connector is perforated or provided with a series of holes that allow air to be vented from the patient line under positive pressure. The hydrophobic membrane is provided as a cylinder that has an outer diameter that fits snugly within an inner diameter of the perforated outer housing. The check valve is provided in the form of an elastomeric sleeve, which is stretched so as to be compressed over the outside of the outer housing, covering the series of holes. Under positive pressure, the elastomeric sleeve is stretched open to allow air vented through the hydrophobic membrane and the series of holes to escape to the atmosphere. When negative pressure is applied to the patient line, e.g., for draining the patient, the elastomeric sleeve is press-fit due to its elastic nature and sucked under the negative pressure to the outer housing, covering the holes of the outer housing. In this manner, ambient air is prevented at all times from entering the patient line.
• In an alternative implementation, which is not used with the punctured and cut solid seal embodiments described above, first and second members are provided and are hinged to an inner wall of the housing. The members are also each spring biased, e.g., with a stainless steel or medically safe plastic spring, wherein the springs are each initially pulled apart and thus biased to close and to rotate their respective member along its hinge point. The members are also initially latched together in a manner preventing the springs from rotating the first and second members. One of the members is positioned to block dialysis fluid flow into the patient's transfer set. The latching of the members forms a latched member and a latching member. Air is vented through a check valve and hydrophobic membrane arrangement as described above, such that air may escape when the patient line is placed under positive pressure but is prevented from entering the patient line when placed under negative pressure. The pressure in the patient connector while air is being vented through the hydrophobic membrane is not enough to rotate the latched member so as to come free from the latching member. However, when the priming fluid, e.g., fresh dialysis fluid, reaches and wets the hydrophobic membrane, the pressure in the patient connector increases enough to release the latched member from the latching member, such that both members are thereafter rotated via the stretched springs returning to their unbiased position. The members remain in the rotated position regardless of whether they are placed under positive or negative fluid pressure to allow dialysis fluid to flow in either direction through the patient connector and the transfer set.
• The patient connectors of the present disclosure reduce the manual effort involved with priming. The connectors also remove a potential source of contamination. The patient is allowed the freedom to connect to the patient line whenever the patient desires instead of being tied to a sequence of priming steps. In some instances, the patient connectors disclosed herein shorten therapy setup time by more than half compared to typical therapy setups. The patient connectors also eliminate or reduce spillage associated with current priming techniques. The use of the patient connectors disclosed herein enable a patient to connect to a patient line then go to sleep as a dialysis system performs self-tests, disposable integrity tests, and priming.
• Any of the above-disclosed structures and associated methodologies may be used in connection with premade dialysis fluid, for example, fluid provided in one or more bag to perform a peritoneal dialysis (“PD”) treatment. It is contemplated, however, to use any one, or more, or all of the above-disclosed structures and associated methodologies with online dialysis fluid generation, such as online PD fluid generation. The online generation of PD fluid involves the addition of concentrates to water that has been purified to a level that is safe for delivery to the patient. The present system and method contemplate the use of a purified water generation unit that uses distillation to perform at least the bulk of the purification. The primary components of the water distillation unit may include a water tank for receiving tap water or other unpurified water, a heater for boiling the unpurified water to create steam, and a condenser to cool the steam to produce highly purified water, wherein impurities from the water are vented and/or collected at the bottom of the heater and delivered to drain. In an alternative embodiment, the tap water tank is not provided and tap water is instead delivered to the heater via house water pressure.
• One or more type of finishing (polishing and/or sterilizing) filter may be located downstream from the condenser, such as, an electrodionization (“EDI”) filter, a de-ionization resin filter, and/or one or more ultrafilter. The downstream finishing filter(s) in an embodiment further purifies the water exiting the condenser from a level of pure or ultrapure to being water for injection (“WFI”) or of an injectable quality, which is suitable for use to form either peritoneal dialysis (“PD”) fluid or a replacement fluid for a blood treatment therapy, such as hemofiltration (“HF”) or hemodiafiltration (“HDF”).
• Optionally, a carbon filter may be placed between the water tank (or house water connection) and the heater to remove chloramines from the tap water prior to reaching the heater. Additionally, a pressure sensor may be located so as to sense pressure in the steam line located between the heater and the condenser. A vent line may be located downstream from the pressure sensor. Valves may be placed in the steam line and the vent line to selectively allow an overpressure in the steam line to be vented to atmosphere and/or volatiles that are freed from the heated water to be vented to atmosphere.
• A temperature sensor is located in one embodiment so as to sense the temperature of the purified water exiting the condenser to ensure that the water is safe to be delivered to the point of use, e.g., a mixing location to be combined with concentrates to form a dialysis fluid. A pressure relief valve is also located along the condenser exit line in an embodiment to relieve excess pressure in the purified water prior to reaching the at least one finishing filter, if provided, or to the point of use if the at least one finishing filter is not provided.
• The water distillation or purification unit may also include multiple conductivity sensors, such as a first conductivity sensor located adjacent to the temperature sensor in the condenser exit line and a second conductivity sensor located just prior to the exit of the WFI from the water distillation unit, e.g., just downstream from the at least one finishing filter.
• In an embodiment, each of the heater, condenser, valves, pressure sensors, temperature sensor and conductivity sensors are under microprocessor control of the control unit for the overall system, which may include one or more processor and one or more memory. In an embodiment, the control unit includes a user interface having a display device under control of a video controller in communication with the at least one processor and the at least one memory. The control unit determines when purified water or WFI is needed and, for example, how much (e.g., data concerning demand). In an embodiment, the control unit also controls the temperature of the purified water or WFI that is outputted. In this manner, the distillation unit may lessen the burden on the inline heater described herein.
• In one embodiment, the water is heated by applying a large AC electrical potential to a pair of electrodes that are submerged in the tap water, wherein the electrodes are separated from each other such that current has to pass through the tap water to complete an electrical circuit. The electrodes are made of a medically compatible and at least somewhat electrically conductive material, such as stainless steel (e.g., 304 or 316) or titanium. The electrodes in an embodiment each include baffles that are interleaved within baffles of the other electrode, so as to increase the overall surface area of adjacently juxtaposed electrode material. The increased surface area increases the speed at which the heater boils the tap water.
• The heater in one embodiment includes an electrically and thermally insulative disposable lining fitted into a rigid base into which the disposable electrodes are placed and held fixed in a non-contacting relationship. Electrical leads are inserted sealingly through a wall of the base and are placed into electrical communication with the electrodes. The electrical leads are connected to a power source, which for example is configured to apply 1000 to 2000 Watts of power to the electrical leads and therefore to the electrodes and tap water located between the electrodes.
• A cover, e.g., an electrically and thermally insulative cover, is removeably, e.g., hingedly, connected to the base, such that the cover allows access to the disposable liner electrodes for replacement. The cover in one embodiment provides two ports, one for connection to a water source (tank or tap water directly), and another for connection to a steam line, which carries steam from the heater to the condenser.
• As is known, the process of distillation involves separating components or substances, in the present case volatiles, from a liquid, in one example tap water, using selective boiling and condensation. The volatiles of the present distillation process are either collected at the bottom of the base of the heater and discharged intermittently from the heater to a drain via a drain valve, are removed via the disposable liner or tray, and/or are vented through a vent in a vent line extending from the top of the heater. It has been found that the more volatile substances are vented to the atmosphere, while the least volatile substances are flushed to the drain or removed via the disposable tray or liner. Water is of intermediate volatility. The most volatile substances boil first and the resultant gas is vented. Water boils next and the resulting gas (steam) is condensed back into liquid. The least volatile parts (including some water) never boil and are flushed to drain or removed via the disposable instead.
• In one embodiment, the condenser includes a condensing coil, which is made of a thermally conductive and medically safe material, such as stainless steel (e.g., 304 or 316) or titanium. Plural heat fins, such as highly thermally conductive copper heat fins, are attached to the coil, e.g., via soldering, welding, brazing, gluing and/or mechanical connection. The heat fins conduct heat away from the coil and the steam located within the coil. The coil includes an inlet and an outlet, wherein the inlet is located at the top of the coil and the outlet is located at the bottom of the coil. In this manner, steam from the heater enters into inlet the top of the coil, while highly purified water exits the outlet at the bottom of the coil.
• The condenser also includes a fan, which is located inside of the coil and associated heat fins. The fan in an embodiment has upper and lower fan blade holders that are attached respectively to upper and lower fixtures via bearings, such as ball or roller bearings. The upper and lower fan blade holders spin around a vertical axis of rotation extending through the centers of each of the bearings. The fan's blades are in an embodiment vertically disposed paddles or baffles that are formed with (e.g., a single molded piece) or are connected to the upper and lower fan blade holders so as to extend radially from the vertical axis of rotation. The upper and lower bearings are placed in a rotationally fixed relationship with upper and lower fixtures, so as to hold the fan blades firmly in place but allow the blades to spin freely about the central, vertical axis of the fan. In an alternative embodiment, the fan blades may be held fixed to a vertical shaft that extends along and spins around the length of the central, vertical axis of rotation.
• The output shaft of a fan motor is coupled via a direct coupler, or via a geared or belt and pulley relationship as desired, to one of the fan blade holders. In operation, the fan motor, under control of the control unit for the dialysis system causes the fan blade holder, the blades connected to the holder, and an opposing holder holding the other end of the fan blades to spin. The spinning of the blades pulls air in from above and below and drives air radially outwardly and over the copper heat fins connected to the condenser coil, causing convective heat transfer away from the steam traveling through the condenser coil.
• In an embodiment, the control unit of the dialysis system is configured to receive a desired purified water exit temperature. The control unit in turn accesses a look-up table or algorithm that correlates the purified water exit temperature with the speed of the fan and boiler power. The control unit in turn sets the boiler power and fan speed to be the correlated fan speed for the desired water exit temperature. In this embodiment, the fan motor for the fan is a variable speed motor and the boiler power is variable. Providing water at a temperature elevated above ambient is advantageous for PD or blood treatment applications, which require the resulting mixed dialysis fluid to be at or near body temperature, e.g., 37° C., as discussed above for the inductive heater. Here, heating energy required by the inductive heater is conserved.
• In an alternative embodiment, the fan motor is a single speed motor and the outlet condenser temperature of the purified water is whatever temperature is achieved via the single speed. It is contemplated in alternative embodiments to provide other types of cooling for the condensing operation, such as water cooling. For example, if a tap water storage tank is provided, it is contemplated to place the condensing coil, e.g., without heat fins, which may again be made be from a medically safe material, such as, stainless steel (e.g., 304, 316) or titanium, in the tap water tank to (i) cool the steam from the heater and (ii) preheat the tap water so that power usage at the heater is reduced. Here, the control unit is programmed to make sure enough tap water is present in the water tank to adequately cool the condensing coil, even if some of the tap water is not eventually purified and is provided instead only for cooling. Multiple water cooled heat exchangers may be provided if desired to condense the steam.
• In an embodiment, the system pump (e.g., peristaltic pump) pumps purified water, e.g., WFI, to the vertically disposed and sterilized bag located within the vertically disposed clamshell holder. To form dialysis fluid from the WFI, the system of the present disclosure adds concentrate and mixes the WFI and concentrate. In an embodiment, the sterilized bag is provided with one or more sterilized tube that is preloaded with one or more concentrate capsule. A slideable plug, e.g., rubber plug, is located at the end of each sterilized tube. The plug is fitted in an airtight manner within the tube so as to maintain the sterility of the bag, tube and concentrate capsules. The slideable plug, the concentrate capsules, and the tube are sized so that the plug and capsules are held press-fittingly within the tube so that neither the plug nor the capsules move until the plug is acted upon as discussed below. The press-fitting of the capsules is enough to hold the capsules in place regardless of the orientation of the sterilized bag. In an alternative embodiment, a thin rupturable seal may be formed or fitted within the tube, capturing the concentrate capsules between the plug and seal.
• The dialysis machine, e.g., at the clamshell holder, provides dispensing actuators, for example, a dispensing actuator for each concentrate capsule containing tube. When the user loads the sterilized bag with concentrate tubes into the clamshell holder, the user also connects the end of each concentrate tube with one of the dispensing actuators. In one embodiment, the user inserts each concentrate tube over an extender located within each dispensing actuator so that the slideable plug within the concentrate tube is abutted against one of the ends of the extender. The extender includes gearteeth extending from a stem in one embodiment, which mesh with mating teeth of one or more rotating gear located within each dispensing actuator. The one or more rotating gear is driven, for example, by a stepper motor, which may index the extender over short and precise distances to in turn translate the plug within the sterilized concentrate tube a short distance, which dispenses one or more concentrate capsule into the WFI located within the sterilized bag.
• The control unit of the overall dialysis system is programmed to cause the stepper motor or other indexer to index the extender a preset distance one or more time during treatment to mix one or more supply of fresh dialysis fluid. Each index may cause one or more concentrate capsule to be delivered to the WFI. As mentioned above, multiple dispensing actuators may be provided, e.g., one for indexing electrolyte capsules and another for indexing osmotic agent capsules. Those two actuators may also be used to dispense other types of capsules, such as pH buffers and diagnostic agents. Or, additional actuators may be provided to dispense the additional capsules. When treatment is completed, the control unit may be programmed to cause the stepper motor or other indexer to reverse direction and pull the extender from the concentrate tube and retreat to a starting position for the next treatment.
• The concentrate capsules may include an outer gel coating forming a sphere or spherocylinder (cylinder with semispherical ends). The gel coating may hold a powder or liquid depending on the type of concentrate. The powder or liquid may have a highest possible concentration so that the capsule is as small as possible. The quantity and concentration of the powdered or liquid concentrate are selected to as to be mixed with a known volume of WFI located within the sterile flexible bag held by the clamshell holder to form a desired dialysis fluid when fully mixed, e.g., a 1.5%, 2.5% or 4.25% dextrose PD solution.
• The control unit is configured to cause the system pump to circulate the WFI and concentrate capsules from and back into the sterile bag multiple times, perhaps reversing direction, so that the gel coatings dissolve, allowing the concentrate powder or liquids to mix homogeneously with the WFI. The control unit may also control the inline heater to partially or fully heat the dialysis fluid during the mixing sequence. In an embodiment, the sterile bag is only partially filled with WFI when the one or more concentrate capsule is added during the mixing sequence to help homogenize the solution more quickly. The remainder of the WFI is then added to reach the desired dialysis fluid formulation. Proportioning is performed on a volumetric basis as described, however, analyzing solution conductivity may be performed alternatively or as a confirmation.
• As mentioned above, it is contemplated to provide one or more diagnostic capsule, which is stored as the last capsule in an electrolyte or osmotic agent tube (or in a separate tune), and which is inserted into a known amount of effluent pumped into the sterilized bag at the end of treatment. It is contemplated to let the diagnostic capsule dissolve into the effluent, after which the patient brings the effluent bag to a clinic for analysis. It is also contemplated for the dialysis system to provide onsite diagnostic equipment, e.g., as part of the dialysis machine, which analyzes the effluent solution. Here, after inserting the one or more diagnostic capsule, the control unit may cause the effluent and capsule to mix in a manner described above. Once the diagnostic concentrate is dispersed homogenously with the effluent, the effluent solution is analyzed. In one embodiment, the effluent solution is analyzed by modulating a light array across a spectrum of wavelengths and measuring the incident light with a photodiode sensor array, which provides more nuanced data as opposed to while light or a color camera.
• Diagnostic capsules may be provided to detect white blood cells or other markers of peritonitis. The capsules may additionally be formulated to look for urea, electrolytes, and phosphates, for example. It is contemplated that the control unit of the system be connected to a server, which may be accessed by any one or more of the provider of the system, a clinician, a doctor's office, a service portal, or a patient website. The effluent data may be tracked, e.g., by the patient's clinician or doctor, to determine the effectiveness of therapy, look for peritonitis or other patient condition needing attention, and possibly to send an updated patient prescription from the clinician or doctor, through the server, to the dialysis system to run a modified treatment.
• While some of the effluent may be used for analysis and sampling as described, it is also contemplated to regenerate the remainder, or at least some of the remainder, of the effluent into purified water, e.g., WFI, for a next treatment. Here, the system pump pumps the effluent to the tap water tank of the water distillation unit. The distillation unit removes the water from the effluent, vaporizing and venting or collecting and discarding effluent residuals. For PD, it is contemplated that the tap water tank of the water distillation unit be sized to hold twice the patient's fill volume worth of tapwater. For instance, if the patient's fill volume is 1.5 liters, the tap water tank may be sized to hold three or more liters of tap water. At the start of treatment, 1.5 liters of tap water is purified into WFI, sent to the flexible bag in the clamshell holder, mixed to produce dialysis fluid, and delivered to the patient. While dwelling within the patient, the second 1.5 liters of tap water is purified into WFI, sent to the flexible bag in the clamshell holder, and mixed to produce dialysis fluid, which waits until the patient dwell and drain to the purification unit of the first fill is completed. The second batch of dialysis fluid is then delivered to the patient. The effluent residing in the purification unit is then purified into WFI, and the above cycle is repeated.
• In light of the disclosure herein and without limiting the disclosure in any way, in a first aspect of the present disclosure, which may be combined with any other aspect listed herein, a dialysis fluid apparatus includes: a flexible dialysis fluid container; a holder structured such that the flexible dialysis fluid container is held vertically within the holder and conforms to a shape of the holder; a pressure sensor positioned and arranged to sense a pressure of a fluid held within the flexible dialysis fluid container; and a control unit configured to (i) store at least one cross-sectional area of the flexible dialysis fluid container, (ii) calculate a head height using the pressure of the fluid held within the flexible dialysis fluid container, and (iii) calculate a volume of the fluid held within the flexible dialysis fluid container using the cross-sectional area and the head height.
• In a second aspect of the present disclosure, which may be combined with any other aspect listed herein, the flexible dialysis fluid container includes a flexible bag.
• In a third aspect of the present disclosure, which may be combined with any other aspect listed herein, the holder is structured as a clamshell having open sides.
• In a fourth aspect of the present disclosure, which may be combined with any other aspect listed herein, the control unit is configured to calculate the head height as a difference in head height of the fluid held within the flexible dialysis fluid container prior to and after a delivery of the fluid to or from the flexible dialysis fluid container.
• In a fifth aspect of the present disclosure, which may be combined with any other aspect listed herein, the head height is a first head height and the volume is a first volume, and wherein the control unit is configured to calculate a second head height and a second volume of the fluid held within the flexible dialysis fluid container using the second head height.
• In a sixth aspect of the present disclosure, which may be combined with any other aspect listed herein, a cross-sectional area for the calculation of the second volume is the same as the cross-sectional area for the calculation of the first volume.
• In a seventh aspect of the present disclosure, which may be combined with any other aspect listed herein, a cross-sectional area for the calculation of the second volume is different than the cross-sectional area for the calculation of the first volume.
• In an eighth aspect of the present disclosure, which may be combined with any other aspect listed herein, the control unit is further configured to (i) store a lookup table that correlates the measured pressure of the fluid held within the flexible dialysis fluid container with cross-sectional area and (ii) obtain the different cross-sectional areas using the lookup table and the first and second measured pressures corresponding respectively to the first and second head heights.
• In a ninth aspect of the present disclosure, which may be combined with any other aspect listed herein, the control unit is further configured to determine a difference between the first and second volumes to determine an amount of the fluid delivered to or removed from the flexible dialysis fluid container.
• In a tenth aspect of the present disclosure, which may be combined with any other aspect listed herein, the control unit is further configured to determine a flowrate of the fluid delivered to or removed from the flexible dialysis fluid container by dividing the difference between the first and second volumes by a time duration between the first and second measured pressures corresponding respectively to the first and second head heights.
• In an eleventh aspect of the present disclosure, which may be combined with any other aspect listed herein, the control unit is further configured to determine the flowrate on a periodic basis.
• In a twelfth aspect of the present disclosure, which may be combined with any other aspect listed herein, calculating head height in (ii) of the first aspect is dependent on the density of the fluid, and wherein the control unit stores a look-up table that correlates fluid density to fluid type.
• In a thirteenth aspect of the present disclosure, which may be combined with any other aspect listed herein, calculating head height in (ii) of the first aspect is dependent on the density of the fluid, and wherein the control unit is configured such that when the fluid held within the flexible dialysis fluid container is mixed, the control unit uses different densities for different head height calculations.
• In a fourteenth aspect of the present disclosure, which may be combined with any other aspect listed herein, the dialysis fluid apparatus includes a level sensor placed in operable communication with the flexible dialysis fluid container, the level sensor outputting to the control unit, the control unit configured to at least one of (i) cause an alarm or (ii) halt delivery of the fluid to or removal of the fluid from the flexible dialysis fluid container when a level of the fluid falls so as to be detected by the level sensor.
• In a fifteenth aspect of the present disclosure, which may be combined with any other aspect listed herein, the level sensor is located so as to sense an area above the flexible dialysis fluid container that transitions in cross-sectional area towards a delivery tube in fluid communication with the flexible dialysis fluid container.
• In a sixteenth aspect of the present disclosure, which may be combined with any other aspect listed herein, the pressure sensor includes a pressure pouch in pressure transmission communication with a pressure transducer, the pressure pouch mounted to the holder such that the flexible dialysis fluid container contacts the pressure pouch.
• In a seventeenth aspect of the present disclosure, which may be combined with any other aspect listed herein, a dialysis fluid apparatus includes: a flexible dialysis fluid container; a peristaltic pump tube placed in fluid communication with the flexible dialysis fluid container; a holder structured such that the flexible dialysis fluid container is held vertically within the holder and conforms to a shape of the holder; a pressure sensor positioned and arranged to sense a pressure of a fluid pumped to or from the flexible dialysis fluid container via the peristaltic pump tube; and a control unit configured to (i) store at least one cross-sectional area of the flexible dialysis fluid container, (ii) calculate a head height using the pressure of the fluid pumped to or from the flexible dialysis fluid container via the peristaltic pump tube, and (iii) calculate a volume of the fluid held within the flexible dialysis fluid container using the cross-sectional area and the head height.
• In an eighteenth aspect of the present disclosure, which may be combined with any other aspect listed herein, the peristaltic pump tube is additionally placed in selective fluid communication with at least one of: a fluid source, a fluid heater, or a patient line.
• In a nineteenth aspect of the present disclosure, which may be combined with any other aspect listed herein, a dialysis fluid apparatus includes: a flexible dialysis fluid container; a holder structured such that the flexible dialysis fluid container is held vertically within the holder and conforms to a shape of the holder; a pressure sensor including a pressure pouch positioned and arranged to contact a bottom of the flexible dialysis fluid container and a pressure transducer in pressure transmission communication with the pressure pouch to sense a pressure of a fluid held within the flexible dialysis fluid container; and a control unit configured to (i) store at least one cross-sectional area of the flexible dialysis fluid container, (ii) calculate a head height using the pressure of the fluid held within the flexible dialysis fluid container, and (iii) calculate a volume of the fluid held within the flexible dialysis fluid container using the cross-sectional area and the head height.
• In a twentieth aspect of the present disclosure, which may be combined with any other aspect listed herein, the pressure pouch and the pressure transducer are in pneumatic communication.
• In a twenty-first aspect of the present disclosure, which may be combined with any other aspect listed herein, an inductive dialysis fluid heater includes: a cylindrical tube including an inner diameter from 4.00 mm to 12.7 mm; a susceptor located within the cylindrical tube; an inductive coil extending around the cylindrical tube in a non-contacting arrangement; and power electronics in electrical communication with the inductive coil and configured to supply an electrical current to the inductive coil, causing the susceptor to heat.
• In a twenty-second aspect of the present disclosure, which may be combined with any other aspect listed herein, the power electronics includes a resonant circuit.
• In a twenty-third aspect of the present disclosure, which may be combined with any other aspect listed herein, the power electronics includes driver electronics for the resonant circuit.
• In a twenty-fourth aspect of the present disclosure, which may be combined with any other aspect listed herein, the susceptor is at least substantially smooth to mitigate a pressure drop caused by the susceptor.
• In a twenty-fifth aspect of the present disclosure, which may be combined with any other aspect listed herein, the susceptor is provided in the form of a mesh.
• In a twenty-sixth aspect of the present disclosure, which may be combined with any other aspect listed herein, the cylindrical tube is a first cylindrical tube and the susceptor is a first susceptor, and which includes a second cylindrical tube and a second susceptor located within the second cylindrical tube, and wherein inductive coil extends around the first and second cylindrical tubes.
• In a twenty-seventh aspect of the present disclosure, which may be combined with any other aspect listed herein, the second cylindrical tube has a same inner diameter as the first cylindrical tube.
• In a twenty-eighth aspect of the present disclosure, which may be combined with any other aspect listed herein, the first and second cylindrical tubes are connected by a U-shaped connector.
• In a twenty-ninth aspect of the present disclosure, which may be combined with any other aspect listed herein, the first and second cylindrical tubes are first and second tube portions folded 180 degrees from a single tube.
• In a thirtieth aspect of the present disclosure, which may be combined with any other aspect listed herein, the inductive dialysis fluid heater includes a downstream temperature sensor located so as to sense a temperature of fluid heated by the first and second susceptors and an upstream temperature sensor located so as to sense a temperature of the fluid prior to being heated, the first and second temperature sensors outputting to a control unit controlling the power electronics.
• In a thirty-first aspect of the present disclosure, which may be combined with any other aspect listed herein, the inductive dialysis fluid heater includes a downstream temperature sensor located so as to sense a temperature of fluid heated by the susceptor and an upstream temperature sensor located so as to sense a temperature of the fluid prior to being heated, the first and second temperature sensors outputting to a control unit controlling the power electronics.
• In a thirty-second aspect of the present disclosure, which may be combined with any other aspect listed herein, a dialysis system includes: a disposable set including a tube, and a susceptor located within the cylindrical tube; a machine enclosure including an opening sized to accept the cylindrical tube; an inductive coil located within the machine enclosure and extending around the cylindrical tube when the cylindrical tube is inserted into the opening; and power electronics located within the machine enclosure, the power electronics in electrical communication with the inductive coil and configured to supply an electrical current to the inductive coil, causing the susceptor to heat.
• In a thirty-third aspect of the present disclosure, which may be combined with any other aspect listed herein, the cylindrical tube is a first cylindrical tube and the susceptor is a first susceptor, and which includes a second cylindrical tube and a second susceptor located within the second cylindrical tube, and wherein inductive coil extends around the first and cylindrical tubes when inserted into the opening.
• In a thirty-fourth aspect of the present disclosure, which may be combined with any other aspect listed herein, the first and second cylindrical tubes are connected by a U-shaped connector.
• In a thirty-fifth aspect of the present disclosure, which may be combined with any other aspect listed herein, the first and second cylindrical tubes are first and second tube portions folded 180 degrees from a single tube.
• In a thirty-sixth aspect of the present disclosure, which may be combined with any other aspect listed herein, the dialysis fluid system includes (i) a downstream temperature sensor located within the machine enclosure so as to sense a temperature of fluid heated by the first and second susceptors when the disposable set is mounted to the machine enclosure and (ii) an upstream temperature sensor located within the machine enclosure so as to sense a temperature of the fluid prior to being heated when the disposable set is mounted to the machine enclosure.
• In a thirty-seventh aspect of the present disclosure, which may be combined with any other aspect listed herein, the dialysis fluid system includes a control unit, the first and second temperature sensors outputting to the control unit controlling the power electronics.
• In a thirty-eighth aspect of the present disclosure, which may be combined with any other aspect listed herein, the dialysis fluid system includes (i) a downstream temperature sensor located within the machine enclosure so as to sense a temperature of fluid heated by the susceptor when the disposable set is mounted to the machine enclosure and (ii) an upstream temperature sensor located within the machine enclosure so as to sense a temperature of the fluid prior to being heated when the disposable set is mounted to the machine enclosure.
• In a thirty-ninth aspect of the present disclosure, which may be combined with any other aspect listed herein, the machine enclosure presents a pump actuator, and wherein the disposable set includes a pumping portion for operation with the pump actuator.
• In a fortieth aspect of the present disclosure, which may be combined with any other aspect listed herein, the pumping portion includes a cylindrical tube which is the same as or is in fluid communication with the cylindrical tube housing the susceptor.
• In a forty-first aspect of the present disclosure, which may be combined with any other aspect listed herein, a patient connector for dialysis includes: a housing including an inlet and an outlet and defining at least one aperture; a seal initially blocking the outlet; a hydrophobic filter covering the at least one aperture; and a check valve positioned and arranged to prevent air from being vented from the housing via the at least one aperture and through the hydrophobic filter when the housing is under atmospheric pressure or negative pressure, the check valve configured to allow air to be vented from the housing via the at least one aperture and through the hydrophobic filter when the housing is under positive pressure.
• In a forty-second aspect of the present disclosure, which may be combined with any other aspect listed herein, the hydrophobic filter is configured to allow air under positive pressure from a patient line connected to the patient connector to be vented through the at least one aperture and to disallow a liquid from escaping through the at least one aperture after the liquid has traveled through the patient line to reach the connector.
• In a forty-third aspect of the present disclosure, which may be combined with any other aspect listed herein, the seal initially blocking the outlet is configured to rupture under pressure from the liquid after reaching the connector and building pressure against the seal.
• In a forty-fourth aspect of the present disclosure, which may be combined with any other aspect listed herein, the seal is configured to rupture due to at least one of its thickness or geometry.
• In a forty-fifth aspect of the present disclosure, which may be combined with any other aspect listed herein, the seal is scored to provide rupture lines.
• In a forty-sixth aspect of the present disclosure, which may be combined with any other aspect listed herein, the patient connector includes a cutting member located within the housing so as to be moved by the liquid reaching the connector to open the seal.
• In a forty-seventh aspect of the present disclosure, which may be combined with any other aspect listed herein, the housing is cylindrical and which includes a cylindrical spike translated by the liquid reaching the connector to pierce the seal.
• In a forty-eighth aspect of the present disclosure, which may be combined with any other aspect listed herein, the patient connector includes a spring-loaded latched member holding the seal so as to initially block the outlet and a spring-loaded latching member latching the latched member so as to prevent the latched member from moving due to its spring-loading to unblock the outlet, and wherein the liquid reaching the connector causes the latched member to become unlatched from the latching member and to move due to its spring-loading so that the seal unblocks the outlet.
• In a forty-ninth aspect of the present disclosure, which may be combined with any other aspect listed herein, the hydrophobic filter is positioned to cover the at least one aperture along an outer wall of the housing, and wherein the check valve is biased to press the hydrophobic filter against the outer wall.
• In a fiftieth aspect of the present disclosure, which may be combined with any other aspect listed herein, the hydrophobic filter is positioned to cover the at least one aperture along an inner wall of the housing.
• In a fifty-first aspect of the present disclosure, which may be combined with any other aspect listed herein, the housing and the hydrophobic filter are cylindrical and the hydrophobic filter is located coaxially within the housing so as to cover the at least one aperture along the inner wall of the housing.
• In a fifty-second aspect of the present disclosure, which may be combined with any other aspect listed herein, the check valve includes an elastomeric sleeve that press-fits over the cylindrical housing so as to cover the at least one aperture, the elastomeric sleeve expanding under positive pressure to allow air to be vented from the housing through the hydrophobic filter and at least one aperture.
• In a fifty-third aspect of the present disclosure, which may be combined with any other aspect listed herein, the housing defines a plurality of apertures and the elastomeric sleeve is cylindrical and sized to cover each of the plurality or apertures.
• In a fifty-fourth aspect of the present disclosure, which may be combined with any other aspect listed herein, a patient connector for dialysis includes: a housing including an inlet and an outlet and defining at least one aperture; a seal initially blocking the outlet; a hydrophobic filter covering the at least one aperture along an inner wall of the housing; and an elastomeric sleeve that press-fits over the housing so as to cover the at least one aperture, the elastomeric sleeve expanding under positive pressure to allow air to be vented from the housing through the hydrophobic filter and at least one aperture.
• In a fifty-fifth aspect of the present disclosure, which may be combined with any other aspect listed herein, the housing and the hydrophobic filter are cylindrical and the hydrophobic filter is located coaxially within the housing so as to cover the at least one aperture along the inner wall of the housing.
• In a fifty-sixth aspect of the present disclosure, which may be combined with any other aspect listed herein, a dialysis fluid priming method includes: configuring a patient connector such that a patient can connect the connector to the patient's indwelling catheter connector prior to delivery of dialysis fluid through a patient line in fluid communication with the patient connector; and enabling the patient to thereafter cause dialysis fluid to be delivered through the patient line, wherein the patient connector (i) allows the dialysis fluid to vent air through the connector, and (ii) allows the dialysis fluid to establish fluid communication between the connector and the patient's indwelling catheter after the air has been vented through the catheter.
• In a fifty-seventh aspect of the present disclosure, which may be combined with any other aspect listed herein, the patient connector closes an opening allowing the air to be vented under atmospheric or negative pressure and opens the opening allowing the dialysis fluid to vent the air through the connector under positive pressure from the incoming dialysis fluid.
• In a fifty-eighth aspect of the present disclosure, which may be combined with any other aspect listed herein, the patient connector provides a seal configured to rupture under pressure from the dialysis fluid to allow the dialysis fluid to establish fluid communication between the connector and the patient's indwelling catheter.
• In a fifty-ninth aspect of the present disclosure, which may be combined with any other aspect listed herein, the patient connector provides a cutting member configured to be moved by the incoming dialysis fluid to pierce a seal to establish fluid communication between the connector and the patient's indwelling catheter.
• In a sixtieth aspect of the present disclosure, which may be combined with any other aspect listed herein, the patient connector provides interlocking members that are unlocked by the incoming dialysis fluid to pierce a seal to establish fluid communication between the connector and the patient's indwelling catheter.
• In a sixty-first aspect of the present disclosure, which may be combined with any other aspect listed herein, a dialysis fluid container includes: a fluid enclosure for holding a fluid; a tube connected to the enclosure; a plug located press-fittingly within the tube; and at least one concentrate capsule located within the tube between the plug and the enclosure.
• In a sixty-second aspect of the present disclosure, which may be combined with any other aspect listed herein, the enclosure includes a flexible bag.
• In a sixty-third aspect of the present disclosure, which may be combined with any other aspect listed herein, the tube and the at least one capsule are sized to hold the at least one capsule in place regardless of an orientation of the container.
• In a sixty-fourth aspect of the present disclosure, which may be combined with any other aspect listed herein, the tube and the at least one capsule are provided in a sterilized form.
• In a sixty-fifth aspect of the present disclosure, which may be combined with any other aspect listed herein, the at least one concentrate capsule is of at least one type selected from the group consisting of an electrolyte capsule, an osmotic agent capsule, a pH buffer capsule and a diagnostic agent capsule.
• In a sixty-sixth aspect of the present disclosure, which may be combined with any other aspect listed herein, the dialysis fluid container includes a plurality of concentrate capsules located within the tube, the capsules provided in an order in which it is intended for the capsules to be dispensed into the enclosure.
• In a sixty-seventh aspect of the present disclosure, which may be combined with any other aspect listed herein, the plurality of capsules includes at least one capsule for each fill cycle of a peritoneal dialysis treatment.
• In a sixty-eighth aspect of the present disclosure, which may be combined with any other aspect listed herein, the plurality of capsules includes at least one pH buffer capsule or at least one diagnostic agent capsule located between the plug and at least one dialysis fluid preparation capsule.
• In a sixty-ninth aspect of the present disclosure, which may be combined with any other aspect listed herein, the tube is a first tube, the plug is a first plug and the at least one concentrate capsule is a first at least one capsule, and which includes a second tube connected to the enclosure, a second plug located press-fittingly within the second tube, and a second at least one concentrate capsule located within the second tube between the second plug and the enclosure.
• In a seventieth aspect of the present disclosure, which may be combined with any other aspect listed herein, the first tube holds at least one first dialysis fluid preparation capsule and the second tube holds at least one second, different dialysis fluid preparation capsule.
• In a seventy-first aspect of the present disclosure, which may be combined with any other aspect listed herein, at least one of the first and second tubes additionally holds at least one pH buffer capsule or at least one diagnostic agent capsule.
• In a seventy-second aspect of the present disclosure, which may be combined with any other aspect listed herein, the at least one concentrate capsule includes an outer gel sphere or sphereocylinder in which a powder or liquid concentrate is held.
• In a seventy-third aspect of the present disclosure, which may be combined with any other aspect listed herein, the powder or liquid is provided in a quantity and concentration that alone or in combination with at least one additional concentrate capsule is proportioned to be mixed with a certain volume of purified water to form a desired dialysis fluid.
• In a seventy-fourth aspect of the present disclosure, which may be combined with any other aspect listed herein, a dialysis fluid container system includes: a fluid enclosure; a tube connected to the enclosure; a plug located press-fittingly within the tube; at least one concentrate capsule located within the tube between the plug and the enclosure; an extender sized to fit within the tube to contact and move the plug to in turn move the at least one concentrate capsule along the tube; and an actuator positioned and arranged to index the extender.
• In a seventy-fifth aspect of the present disclosure, which may be combined with any other aspect listed herein, the actuator includes at least one driver contacting the extender and an indexer operably coupled to move the at least one driver to in turn index the extender.
• In a seventy-sixth aspect of the present disclosure, which may be combined with any other aspect listed herein, the at least one driver includes at least one rotating gear and the extender includes gear teeth sized to mate with the at least one rotating gear.
• In a seventy-seventh aspect of the present disclosure, which may be combined with any other aspect listed herein, the at least one rotating gear includes first and second rotating gears, and wherein the actuator includes a third rotating gear that rotates along a same shaft as the first rotating gear and a fourth rotating gear in geared communication with the third rotating gear, the fourth rotating gear rotating along a same shaft as the second rotating gear, and wherein the indexer is coupled to one of the third or fourth rotating gears.
• In a seventy-eighth aspect of the present disclosure, which may be combined with any other aspect listed herein, the indexer includes a stepper motor.
• In a seventy-ninth aspect of the present disclosure, which may be combined with any other aspect listed herein, the actuator and extender are reusable.
• In an eightieth aspect of the present disclosure, which may be combined with any other aspect listed herein, at least a portion of the actuator is mounted to a holder for holding the fluid enclosure.
• In an eighty-first aspect of the present disclosure, which may be combined with any other aspect listed herein, a dialysis fluid system includes: a fluid enclosure; a tube connected to the enclosure; a plug located press-fittingly within the tube; at least one concentrate capsule located within the tube between the plug and the enclosure; an extender sized to fit within the tube to contact and move the plug to in turn move the at least one concentrate capsule along the tube and into the fluid enclosure; and fluid lines and a pump positioned and arranged to circulate purified water through fluid enclosure and the fluid lines after the at least one concentrate capsule has been moved into the fluid enclosure to mix the purified water and concentrate held by the at least one concentrate capsule.
• In an eighty-second aspect of the present disclosure, which may be combined with any other aspect listed herein, the dialysis fluid system includes a control unit configured to (i) store an amount of the purified water to mix with the at least one concentrate capsule and (ii) cause only a portion of the amount to be mixed initially with the at least one concentrate capsule.
• In an eighty-third aspect of the present disclosure, any of the structure and functionality disclosed in connection withFIGS.1 to26 may be combined with any of the other structure and functionality disclosed in connection withFIGS.1 to26.
• In light of the present disclosure and the above aspects, it is therefore an advantage of the present disclosure to provide an improved volume control apparatus and associated methodology for a dialysis system.
• It is another advantage of the present disclosure to provide an improved dialysis fluid heating apparatus and associated methodology for a dialysis system.
• It is a further advantage of the present disclosure to provide an improved patient line connector and associated methodology for a dialysis system.
• It is still another advantage of the present disclosure to provide an improved dialysis fluid concentrate mixing apparatus and associated methodology for an online dialysis system.
• It is still a further advantage of the present disclosure to provide an improved online dialysis system.
• It is yet another advantage of the present disclosure to provide a regenerative dialysis system.
• Additional features and advantages are described in, and will be apparent from, the following Detailed Description and the Figures. The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the figures and description. Also, any particular embodiment does not have to have all of the advantages listed herein, and it is expressly contemplated to claim individual advantageous embodiments separately. Moreover, it should be noted that the language used in the specification has been selected principally for readability and instructional purposes, and not to limit the scope of the inventive subject matter.
BRIEF DESCRIPTION OF THE FIGURES
• FIG.1 is a perspective view of one embodiment of an online and regenerative dialysis system of the present disclosure.
• FIG.2 is a perspective view of one embodiment of a purified water generation unit or distillation unit of the present disclosure, which may be used in the overall system.
• FIG.3 is a schematic view of a purified water generation unit or distillation unit showing one embodiment of an overall flowpath, sensing, valving, optional pumping and control arrangement.
• FIG.4 is a perspective view of one embodiment of a heater for the purified water generation unit or distillation unit of the present disclosure and one possible electrical arrangement for same.
• FIG.5 is a sectioned view illustrating one embodiment of a concentrate dispensing subsystem and associated methodology of the present disclosure.
• FIG.6 is a front elevation view of one embodiment of a dispensing actuator of the subsystem of the present disclosure.
• FIG.7 is a side-sectioned elevation view of the dispensing actuator of the subsystem of the present disclosure.
• FIG.8 is a perspective view of one embodiment for an onsite diagnostic equipment used to analyze a patient's effluent fluid.
• FIG.9 is a side view of one embodiment of a dialysis fluid volume control subsystem of the present disclosure showing a fluid level at a first level.
• FIG.10 is a front view of one embodiment of a dialysis fluid volume control subsystem of the present disclosure.
• FIG.11 is a side view of one embodiment of a dialysis fluid volume control subsystem of the present disclosure showing a fluid level at a second level.
• FIG.12 is a side view of one embodiment of a dialysis fluid volume control subsystem of the present disclosure showing a fluid level at a third level.
• FIG.13 is a perspective view of an alternative gravity fed system that employs the dialysis fluid volume control subsystem of the present disclosure.
• FIG.14 is an elevation view of a first inline fluid heater configuration of the present disclosure.
• FIG.15 is an elevation view of a second inline fluid heater configuration of the present disclosure.
• FIG.16 is a graph illustrating an example output of the inline fluid heater of the present disclosure.
• FIGS.17 and18 are schematic views of a first embodiment for a self-priming patient connector of the present disclosure.
• FIG.19 is a schematic view of the self-priming patient connector ofFIGS.17 and18 having a solid seal configured to rupture under fluid pressure.
• FIG.20 is a schematic view of the self-priming patient connector ofFIGS.17 and18 having a cutting member positioned to cut a solid seal open under fluid pressure.
• FIG.21 is an exploded perspective view of a second embodiment for a self-priming patient connector of the present disclosure.
• FIGS.22 to24 are schematic views of a third embodiment for a self-priming patient connector of the present disclosure.
• FIG.25 is a perspective view of a first alternative embodiment of an online and regenerative dialysis system of the present disclosure, which includes a dedicated drain container or bag.
• FIG.26 is a perspective view of a second alternative embodiment of an online and regenerative dialysis system of the present disclosure, which includes an alternative structure for determining an amount of a patient drain.
DETAILED DESCRIPTIONSystem Overview
• Referring now to the drawings and in particular toFIG.1, adialysis system10 is illustrated.Dialysis system10 as illustrated and described herein is capable of preparing purified water or water for injection (“WFI”), mixing the purified water or WFI with concentrate to form dialysis fluid online, heating the dialysis fluid inline, and delivering the dialysis fluid to patient P via a self-priming patient connector. It should be appreciated however that various alternative embodiments are described herein, which do not have to have each of the above features and corresponding structures. It is expressly contemplated that the features and corresponding structures are patentable separately and in any combination. It should also be appreciated that while the present disclosure is described generally for peritoneal dialysis (“PD”), many of the features and corresponding structure are useful in other modalities, such as hemodialysis (“HD”), hemofiltration (“HF”), hemodiafiltration (“HDF”) and/or medical fluid delivery generally.
• In the illustrated embodiment ofFIG.1,system10 includes adistillation unit12, which purifies tap water or used dialysis fluid into purified water or WFI. As used herein, purified water includes WFI, however purified water may be less sterile than WFI. For example, purified water may be suitable for HD, which pumps dialysis fluid along one side of dialyzer membranes, while WFI may be required for PD, which along with other modalities directs dialysis fluid to patient P.
• Purified water is delivered fromdistillation unit12 to a dialysisfluid mixing container100, such as a flexible bag. Dialysisfluid mixing container100 in the one embodiment is placed within a holder152 (FIG.9) of a dialysis fluidvolume control subsystem150. Dialysis fluid is prepared within dialysisfluid mixing container100 in an embodiment by supplying one ormore tube108a,108b(FIG.5) connected to dialysisfluid container100. As illustrated in detail below, a plug is located press-fittingly near a distal end of the tube. At least one concentrate capsule110 (FIG.6) is located withintube108a,108bbetween the plug and dialysisfluid container100. Concentratecapsules110 contain powdered or liquid concentrate for mixing with purified water to create dialysis fluid, provide a pH buffer or perform a diagnostic function. In an embodiment, a plurality oftubes108a,108bare provided, which each may carry one or more dialysis fluid constituent capsule, such as an electrolyte capsule and an osmotic agent along with other capsules if desired. The amount and concentration of the concentrate withincapsules100 is mixed with a certain volume of purified water to make a desired volume (e.g., fill volume of patient P) and type (per prescription of patient P) of dialysis fluid. The use of theconcentrate capsules110 enables dialysis fluid to be generated without thedialysis system10 needing to be configured for determining precise measurements of concentrate, thereby saving dialysis machine costs. Instead, theconcentrate capsules110 are precisely formed at the time of manufacture to have a known quantity of concentrate.
• As illustrated in detail below (not shown inFIG.1), at least one actuator is provided, e.g., one for eachtube108a,108b, which indexes an extender against the plug and at a desired time move the plug so as to push the plug so as to dislodge one or more concentrate capsule fromtube108a,108binto dialysisfluid container100. The one or more actuator may be mounted for example onholder152. The actuator includes an indexer, such as a stepper motor, that under control orcontrol unit24 causes the extender to be indexed a precise amount to dislodge a desired one ormore concentrate capsule110 into dialysisfluid mixing container100.Pump actuator82 under control ofcontrol unit24 may cycle the purified water and one or more concentrate capsule as it dissolves to help the concentrate to become mixed homogeneously.
• In the illustrated embodiment,holder152 includes apressure sensor160 positioned and arranged to sense a pressure of a fluid held within dialysisfluid mixing container100.Pressure sensor160 outputs to acontrol unit24, which uses the sensed pressure to determine a head height of the dialysis fluid located withindialysis fluid container100, which is constrained to have a certain shape byholder152. The cross-sectional area of mixingcontainer100 is known accordingly, allowingcontrol unit24 to know a volume of dialysis fluid withindialysis fluid container100. By subtracting volumes before and after a fill or drain of patient P,control unit24 may determine an accurate amount of fresh dialysis fluid delivered to the patient or used dialysis fluid removed from the patient. By dividing intermediate volume differences by known time durations,control unit24 may determine instantaneous, or virtually instantaneous, flowrate, and modify same if needed.
• Dialysis fluid is pumped bypump actuator82, which may be a tube or peristaltic pump actuator, through aninline heater180.Heater180 is in one embodiment an inductive heater, which heats the dialysis fluid from whatever temperature it is upstream of heater180 (may have residual heat fromdistillation unit12 and/or may be heated during mixing) to a desired body temperature, such as 37°C. Inductive heater180 as discussed in detail below places one or more susceptors within one or more portion of acylindrical heating tube92, which are mounted for operation within aninductive coil182 that extends around the one or more portion of the cylindrical heating tube in a non-contacting arrangement.Inductive heater180 further includes power electronics that are in electrical communication withinductive coil182 and are configured to supply an electrical current to the inductive coil, causing the susceptor to heat. The power electronics are under control ofcontrol unit24 in one embodiment.
• Heated dialysis fluid is delivered to patient P viapump actuator82 and a self-primingpatient connector200. Self-priming patient connector200 as illustrated in detail below includes a hydrophobic filter and a check valve. The hydrophobic filter is positioned adjacent to one more aperture formed in the housing. The check valve prevents air from entering the patient connector under atmospheric or negative pressure (e.g., during a drain of patient P). The check valve is opened under positive air pressure, e.g., whilepump actuator82 is pumping fresh dialysis fluid alongpatient line94d, pushing air out ofpatient connector200 via the at least one aperture and the hydrophobic filter, past the opened check valve. Self-ventingpatient connector200 is provided initially with a seal at its outlet, which aids in forcing the air out through the at least one aperture and the hydrophobic filter. Once all air inpatient line94dhas been purged, the pressure in self-ventingpatient connector200 builds under liquid pumping pressure, rupturing the seal or causing a cutting member to pierce the seal. At this point, withpatient line94dfully primed, fresh, heated dialysis fluid may flow to patient P under positive pressure and used dialysis fluid may be removed from patient P under negative pressure. In the illustrated embodiment ofFIG.1, used dialysis fluid is returned todistillation unit12 viareturn line94eto be converted to purified water, e.g., WFI. In an alternative embodiment, used dialysis fluid is delivered viareturn line94einstead to drain.
• In addition to pumpactuator82, such as a peristaltic pump actuator, a dialysisfluid actuation assembly80 ofsystem10 also includesvalve actuators84ato84e, which may be electrically actuated solenoid pinch valve actuators (or motor driven bi-stable pinch valve actuators) that selectively pinch a fluid line closed or allow that fluid line to be open to allow flow. In an embodiment,valve actuators84ato84eare fail safe, such that upon a loss of power, the valves close automatically.FIG.1 also illustrates that dialysisfluid actuation assembly80 provides a patientfluid pressure sensor86, which senses the pressure of fresh dialysis fluid being delivered to and used dialysis fluid being removed from patient P. As indicated by the dotted lines extending therefrom, each ofpump actuator82,valve actuators84ato84e, and patientfluid pressure sensor86 are under control of, or output to, controlunit24. For example,control unit24 may be programmed to receive feedback from patientfluid pressure sensor86 to ensure that positive pressure provided bypump actuator82 pumping fresh dialysis fluid to patient P, and negative pressure provided bypump actuator82 removing used dialysis fluid from patient P, does not exceed positive and negative patient pressure limits, respectively.
• A portion of the components of dialysisfluid actuation assembly80 are housed withinhousing20 along with the inline heater and components ofdistillation unit12 discussed herein, while a portion of those components are presented on a surface ofhousing20 for operation with adisposable unit90.Disposable unit90 includes (i) pumpingline92 that interfaces with an exposed portion ofpump actuator82,inline heater180 andpressure sensor86, (ii) a purified water, e.g., WFI,line94athat interfaces with an exposed portion ofvalve84a, (iii) a mixing container inlet/outlet line94bthat interfaces with an exposed portion ofvalve84b, (iv) a mixing container inlet/outlet line94cthat interfaces with an exposed portion ofvalve84c, (v)patient line94dthat interfaces with an exposed portion ofvalve84d, and (vi)return line94ethat interfaces with an exposed portion ofreturn valve84e. Disposable set90 also includes a mixingcontainer100 connected to mixing container inlet/outlet lines94band94c. Disposable set90 further includes a self-primingpatient connector200 located at a distal end ofpatient line94d.
Distillation Unit
• Referring now toFIGS.2 to4, adistillation unit12 configured to produce purified water, e.g., WFI, is illustrated in further detail. The primary components ofwater distillation unit12 may include a water (or used dialysis fluid)tank14 for receiving tap water (or used dialysis fluid) or other unpurified water by hand or via house water pressure, aheater30 for boiling the unpurified water to create steam, and acondenser50 to cool the steam to produce highly purified water, wherein impurities from the water are vented and/or collected at the bottom ofheater30 and delivered to drain. In an alternative embodiment,tap water tank14 is not provided and tap water is instead delivered toheater30 directly via house water pressure.
• One or more type of finishing (polishing and/or sterilizing)filter16,18a/18bmay be located downstream fromcondenser50, such as, an electrodionization (“EDI”) filter (or a de-ionization resin filter)16 and/or one or more ultrafilter18aand18b. The downstream finishing filter(s) in an embodiment further purifies thewater exiting condenser50 from a level of pure or ultrapure to being water for injection (“WFI”) or of an injectable quality, which is suitable for use to form either peritoneal dialysis (“PD”) fluid or a replacement fluid for a blood treatment therapy, such as hemofiltration (“HF”) or hemodiafiltration (“HDF”).
• Optionally, acarbon filter22 may be placed alongunpurified water line60abetween water tank14 (or house water connection) andheater30 to remove chloramines from the tap water prior to reaching the heater. Additionally, apressure sensor62 may be located so as to sense pressure in asteam line60blocated betweenheater30 andcondenser50. Avent line60cmay be located downstream frompressure sensor62.Valves64band64cmay be placed respectively insteam line60band ventline60cto selectively allow an overpressure in the steam line to be vented to atmosphere and/or volatiles that are freed from the heated water to be vented to atmosphere.
• A temperature sensor66 is located along condenser exit or purifiedwater line60din one embodiment so as to sense the temperature of the purifiedwater exiting condenser50 to ensure that the water is safe to be delivered to the point of use, e.g., a mixing location to be combined with concentrates to form a dialysis fluid. Apressure relief valve68 is also located alongpurified water line60din an embodiment to relieve excess pressure in the purified water prior to reaching at least one finishingfilter16,18a/18b, if provided, or to the point of use if the at least one finishing filter is not provided. Thepressure relief valve68 may be provided for safety (e.g., may be optional) since typically energy input into theheater30 is balanced by a capacity of thecondenser50 so that nearly all steam is condensed into the water as the water flows to the purifiedwater line60d.
• Water distillation orpurification unit12 may also include multiple conductivity sensors, such as afirst conductivity sensor70alocated adjacent to the temperature sensor66 in purifiedwater line60dand asecond conductivity sensor70blocated in sterilizingline60ejust prior to the exit of the WFI fromwater distillation unit12 viaWFI valve64flocated alongWFI line60f, e.g., just downstream from at least one finishingfilter16,18a/18b. Abypass line60gbranches off ofWFI line60f(orpurified water line60d) and extends to adrain76. Animpurities removal valve64his located to selectively open and closeimpurities removal line60hto drain76. In some embodiments, a separate drain may be fluidly coupled to theimpurities removal line60hto provide fluid isolation from thebypass line60g. The separation of thelines60gand60hmay prevent bacteria or mold from inadvertently reaching purified water.
• FIG.3 illustrates that awater level sensor72 may be located inthermally insulative base32 ofheater30 to detect how much unpurified water or used dialysis fluid has been introduced viaunpurified water valve64aand/or to provide a low level detection for when more unpurified water needs to be filled viawater valve64a. To that end, multiplewater level sensors72, e.g., high and low sensors, may be provided.
• It is contemplated fordistillation unit12 to provide at least one pump if needed, such as an unpurified water pump74aonly, apurified water pump74bonly, or bothpumps74aand74b.Pumps74amay be gear pumps or other types of electromechanical pumps, e.g., whereunpurified water line60ais non-disposable, e.g., stainless steel. Ifunpurified water line60aand/orWFI line60fare instead made of disposable tubing or as part of a disposable cassette, pumps74aand74bmay instead be peristaltic pumps or pneumatically or electromechanically actuated, volumetric cassette sheeting pumps. In any case,downstream pump74bmay provide a sterilized interface for use with the purified water, e.g., peristaltic pumps or pneumatically or electromechanically actuated, volumetric cassette sheeting pumps.
• In some embodiments, the unpurified water pump74aand/or the purifiedwater pump74bmay be omitted since pressure from boiling water in theheater30 causes the water vapor to flow to thecondenser50. Thecontrol unit24 may be configured to balance input power to theheater30 with a condensation rate of thecondenser50 to maintain a desired pressure to produce a desired flow rate of water. While this approach may use more power for theheater30 to reach a desired pressure, it is offset from not having the unpurified water pump74aand/or the purifiedwater pump74b.
• As indicated by the dotted lines extending therefrom, each of theheater30,condenser50,pressure sensor62,valves64ato64cand64fto64h, temperature sensor66 andconductivity sensors70aand70bmay be under microprocessor control of thecontrol unit24 foroverall system10, which may include one or more processor and one or more memory. In an embodiment,control unit24 includes auser interface26 having a display device under control of a video controller in communication with the at least one processor and the at least one memory. One ormore speaker28 is provided to output sounds, e.g., alarms or voice guidance to the user.Control unit24 determines when purified water, e.g., WFI, is needed and, for example, how much (e.g., data concerning demand). In an embodiment,control unit24 also controls the temperature of the purified water, e.g., WFI that is outputted. In this manner,distillation unit12 may lessen the burden on the inline heater described herein.
• In one embodiment, the water is heated by applying a large AC electrical potential to a pair ofelectrodes40aand40b, which are submerged in the tap water or used dialysis fluid, wherein the electrodes are separated from each other such that current has to pass through the tap water to complete an electrical circuit.Electrodes40aand40bare made of a medically compatible and at least somewhat electrically conductive material, such as stainless steel (e.g.,304,316, or316L) or titanium.Electrodes40aand40b, in an embodiment, each include baffles that are interleaved within baffles of the other electrode, so as to increase the overall surface area of adjacently juxtaposed electrode material. A combination of a surface area of theelectrodes40aand40band a distance between theelectrodes40aand40bdetermines a resistance of the water therebetween. A conductivity of the water may also affect the resistance. Thecontrol unit24 may vary the amount of power applied to theelectrodes40aand40bto compensate for the resistance of the water. The spacing and surface area of theelectrodes40aand40baccommodate an expected feed water conductivity and a range of power that can be applied to enable theheater30 to meet water generation requirements of thesystem10.
• In another embodiment, the water is heated using inductive heating. In this embodiment, a non-disposable stainless steel metal plate is inductively heated. The metal plate is placed inside of a disposable heating chamber.
• As illustrated inFIG.2,heater30 in one embodiment includes an electrically and thermally insulative removeable and disposable tray orliner42 fitted into arigid base32, into whichdisposable electrodes40aand40bare placed and held fixed in a non-contacting relationship.FIG.4 illustrates that electrical leads44 are inserted sealingly through a wall ofbase32 and are placed into electrical communication withelectrodes40aand40b. Electrical leads44 are connected to apower source46, which for example is configured to apply 1000 to 2000 Watts of power toelectrical leads44 and therefore toelectrodes40aand40band tap water or used dialysis fluid located between the electrodes.
• Acover34, e.g., an electrically and thermally insulative cover, is removeably, e.g., hingedly, connected tobase32, such thatcover34 allows access to the disposable liner and electrodes for replacement.Cover34 in one embodiment provides two ports, oneport36 for connection to a water source14 (tank or tap water directly) viaunpurified water line60a, and anotherport38 for connection to asteam line60b, which carries steam fromheater30 tocondenser50.
• As is known, the process of distillation involves separating components or substances, in the present case volatiles, from a liquid, in one example tap water and in another example used dialysis fluid, using selective boiling and condensation. The volatiles of the present distillation process are either collected at the bottom ofbase32 ofheater30 and discharged intermittently fromheater30 to adrain76 via animpurities valve64hand impurities line60h, are removed via disposable tray orliner42, and/or are vented through a vent in avent line60cextending from the top ofheater30. It has been found that the more volatile substances are vented to the atmosphere, while the least volatile substances are flushed to the drain or removed via disposable tray orliner42. Water is of intermediate volatility. The most volatile substances boil first and the resultant gas is vented. Water boils next and the resulting gas (steam) is condensed back into liquid. The least volatile parts (including some water) never boil and are flushed to drain or removed via the disposable instead.
• In one embodiment,condenser50 includes a condensingcoil52, which is made of a thermally conductive and medically safe material, such as stainless steel (e.g.,304,316, or316L) or titanium. Plural heat fins (not illustrated), such as highly thermally conductive copper heat fins, are attached tocoil52, e.g., via soldering, welding, brazing, gluing and/or mechanical connection. The heat fins conduct heat away fromcoil52 and the steam located within the coil. The coil includes aninlet54 and anoutlet56, whereininlet54 is located at the top ofcoil52 andoutlet56 is located at the bottom ofcoil52 in the illustrated embodiment. In this manner, steam fromheater30 entersinlet54 at the top ofcoil52, while highly purifiedwater exits outlet56 at the bottom ofcoil52.
• The condenser also includes afan58, which is located inside ofcoil52 and associated heat fins.Fan58 in an embodiment has upper and lower fan blade holders (not illustrated) that are attached respectively to upper and lower fixtures via bearings (not illustrated), such as ball bearings. The upper and lower fan blade holders spin around a vertical axis of rotation A extending through the centers of each of the bearings.Multiple blades58aoffan58 are in an embodiment vertically disposed paddles or baffles that are formed with (e.g., as a single molded piece) or are connected to the upper and lower fan blade holders so as to extend radially from the vertical axis of rotation A. The upper and lower bearings are placed in a rotationally fixed relationship with upper and lower fixtures, so as to holdfan blades58afirmly in place but allow the blades to spin freely about the central, vertical axis A offan58. In an alternative embodiment,fan blades58amay be held fixed to a vertical shaft (not illustrated) that extends along and spins around the length of the central, vertical axis of rotation A.
• The output shaft of afan motor58bis coupled via a direct coupler, or via a geared or belt and pulley relationship as desired (not illustrated), to one of the fan blade holders. In operation, thefan motor58b, under control ofcontrol unit24 fordialysis system10 causes the coupled fan blade holder,blades58aconnected to the coupled holder, and an opposing holder holding the other end offan blades58ato spin. The spinning ofblades58apulls air in from above and below and drives air radially outwardly and over the copper heat fins connected tocondenser coil52, causing convective heat transfer away from the steam traveling throughcondenser coil52.
• In an embodiment,control unit24 ofdialysis system10 is configured to receive a desired purified water exit temperature from the user or a patient's prescription.Control unit24 in turn accesses a look-up table or algorithm that correlates the purified water exit temperature with the speed offan58 and boiler power ofheater30.Control unit24 in turn sets the boiler power and fan speed to be the correlated boiler power and fan speed for the desired water exit temperature. In this embodiment,fan motor58boffan58 is a variable speed motor and the boiler power ofheater30 is variable. Providing purified water, e.g., WFI, at a temperature elevated above ambient is advantageous for PD or blood treatment applications, which require the resulting mixed dialysis fluid to be at or near body temperature, e.g., 37° C., as discussed herein for the inductive heater. Here, heating energy required by the inductive heater is conserved.
• In an alternative embodiment,fan motor58bis a single speed motor and the outlet temperature atcondenser50 for the purified water is whatever temperature is achieved via the single speed. It is contemplated in alternative embodiments to provide other types of cooling for the condensing operation, such as water cooling. For example, if tap water or used dialysisfluid storage tank14 is provided, it is contemplated to place condensingcoil52, e.g., without heat fins, which may again be made be from a medically safe material, such as, stainless steel (e.g.,304,316) or titanium, intotank14 to (i) cool the steam fromheater30 and (ii) preheat the tap water so that power usage byheater30 is reduced. Here,control unit24 is programmed to make sure enough tap water is present intank14 to adequately cool condensingcoil52, even if some of the tap water is not eventually purified and is provided instead only for cooling. Multiple water cooled heat exchangers may also be provided if desired to help condense the steam.
• FIGS.1 and2 illustrate thatdistillation unit12 is housed within ahousing20, which may be made of plastic, metal or combinations thereof. It should be appreciated thathousing20 may additionally house or support any of reusable structures described herein, such asholder152 for volume determination,pump actuator82, and theinductive coil182 of theinductive heater180.Housing20 as illustrated houses controlunit24 and provides a location for mountinguser interface26 andspeakers58.
• Additional information regardingdistillation unit12 may be found in co-pending U.S. provisional patent application No. 62/967,129, entitled “Medical Fluid Therapy System And Method Employing Distillation”, filed contemporaneously with the present disclosure, the entire contents of which are incorporated herein by reference and relied upon.
Dialysis Fluid Preparation
• Referring now toFIGS.1 and5, a pump ofdistillation unit12, such as purifiedwater pump74b, withvalves84aand84bopen and all other valves closed, pumps purified water, e.g., WFI, through purifiedwater line94aand mixing container inlet/outlet line94bto vertically disposed and sterilized container orbag100 located within a vertically disposedclamshell holder152 discussed in detail below. Alternatively, ifdistillation unit12 is not provided with a pump, or perhaps only with unpurified water pump74a, purified water, e.g., WFI, may instead be pumped bysystem pump actuator82, withvalves84aand84copen and all other valves closed, through purifiedwater line94a, pumpingline92, and mixing container inlet/outlet line94cto mixing container orbag100. Mixing container orbag100 inFIG.5 is accordingly illustrated as having a first inlet/outlet port102 and a second inlet/outlet port104.Ports102 and104 may each be used as an inlet or an outlet port, or perhaps only asingle port102 or104 is provided, which is used as both an inlet and an outlet port.
• FIGS.1 and5 illustrate that mixing container orbag100 may be provided with anidentifier106, e.g., a barcode, 2D barcode, QR code or other marking that may be read by a scanner, e.g., a camera or reader. In an embodiment, the reader is a camera provided by patient P's (or caregiver's)smartphone98 as part of an application (“app”) that is used to begin and track a treatment.Control unit24 in an embodiment includes a wireless transceiver that communicates wirelessly with the user'ssmartphone98 to exchange information with the dialysis treatment app. In an embodiment, the user opens the dialysis treatment app, which prompts the user to scanidentifier106, which scan is read and converted by the app into information for sending wirelessly to controlunit24 ofsystem10. In an embodiment, the app also prompts patient P or caregiver to enter whether the patient is currently full of dialysis fluid, the answer to which is sent to controlunit24, so that the control unit may know whether or not to begin treatment with a drain, and if so, to know how much tap water, if any, needs to be added totank14 ofdistillation unit12.
• In an embodiment, the information transferred fromidentifier106, to the app, to controlunit24 includes all information needed for treatment, including but not limited to: (i) number of patient fills, (ii) volume per fill, (iii) number of patient drains (may be different than number of patient fills if the last fill is to remain with patient P after disconnecting from disposable set90), (iii) solution type, e.g., dextrose or glucose level, for each fill, and (iv) dwell time following each patient fill. In an embodiment,control unit24 knows the prescription, or perhaps multiple approved prescriptions for patient P and analyzes the above information (including concentrate contents) to make sure it falls under or complies with at least one of patient P's prescriptions, such that if it is attempted to use anon-approved container100,control unit24 causesuser interface26 and/orspeakers28 to alarm and prevent treatment from proceeding until aproper container100 is loaded and scanned. Similarly, the information provided byidentifier106 may include the identification of theparticular mixing container100, such that if it is attempted to use the same container100 a second time, which no longer contains concentrate, controlunit24 will causeuser interface26 and/orspeakers28 to alarm and prevent treatment from proceeding until anew container100 is loaded and scanned.
• In case the patient or caregiver does not have or is not comfortable with using a smartphone, it is contemplated to also provide the scanner as part ofuser interface26 athousing20, to which the user pressesidentifier106 of mixingcontainer100, which is empty of fluid. Here, the app is not necessary.User interface26 is alternatively a wireless smart device, such as a tablet. In any embodiment for user interface, the information discussed above is obtained bycontrol unit24 fromidentifier106.
• At least some of the information provided above corresponds to the concentrates provided with mixingcontainer100. As illustrated inFIGS.1 and5, sterilized mixing container orbag100 is provided with one or more sterilizedtube108a,108bthat is preloaded with one ormore concentrate capsule110. Aslideable plug112, e.g., rubber plug, is located at a distal end of each sterilizedtube108a,108b.Plug112 is fitted in an airtight manner within eachtube108a,108b, so as to maintain the sterility of the bag, tube and concentrate capsules. Although not illustrated, a tearaway cap may be proved at the distal end of eachtube108a,108b, for transport and to ensure sterility prior to use.
• In the illustrated embodiment,slideable plugs112, concentratecapsules110, andtubes108a,108bare sized so that plugs112 andcapsules110 are held press-fittingly withintubes108a,108b, so that neither the plugs nor the capsules move until aplug112 is acted upon as discussed below. The press-fitting ofcapsules110 is enough to hold the capsules in place regardless of the orientation of mixingcontainer100. In an alternative embodiment, a thin rupturable seal (not illustrated) may be formed or fitted within eachtube108a,108b, capturing and holdingconcentrate capsules110 betweenplug112 and the seal prior to use.
• As illustrated inFIGS.5 and6,housing20 ofdialysis system10, e.g., atclamshell holder152, provides dispensingactuators120a,120b, for example, a dispensingactuator120a,120bfor each concentratecapsule containing tube108a,108b. InFIG.5, when the user loads sterilized mixingcontainer100 havingconcentrate tubes108a,108bintoclamshell holder152, the user also connects the end of eachconcentrate tube108a,108bwith one of the dispensingactuators120a,120b. In the illustrated embodiment ofFIG.5, the user inserts eachconcentrate tube108a,108bover anextender122 located within each dispensingactuator120a,120b, so thatslideable plug112 within eachconcentrate tube108a,108bis abutted against one of the ends of theextender122a,122b.
• FIG.6 illustrates an alternative embodiment, in which a portion of dispensingactuators120a,120bis disposable. Here,capsule containing tubes108a,108bare each provided with adistal flange108cthat is press-fitted onto adisposable housing124.Disposable housing124 holdsextender122, which is likewise disposable.
• In eitherFIG.5 in which extender122 is reusable orFIG.6 in which extender122 is disposable, the extender includes gearteeth122aextending from astem122bin one embodiment.Gearteeth122amesh with mating teeth of one or more driver orrotating gear126a,126blocated within each dispensingactuator dispensing actuators120a,120b. InFIG.5, one or more driver orrotating gear126a,126bis reusable, while inFIG.6, one or morerotating gear126a,126bis disposable. In either case, one or more driver orrotating gear126a,126bis driven by an indexer, for example, a stepper motor, which indexes extender122 over short and precise distances to in turn translateplug112 within the sterilizedconcentrate tubes108a,108ba short distance, which dispenses one ormore concentrate capsule110 into the WFI, which has been pumped into sterilized mixingcontainer100.
• FIG.7 illustrates an embodiment in which asingle indexer130, e.g., a stepper motor, turns both rotatinggears126a,126bin opposite directions to advanceextender122 in a desired direction.Indexer130 is under control ofcontrol unit24 as indicated by the dotted line extending from the indexer.FIG.7 also illustrates that athird gear132aand afourth gear132bare provided, which may be worm gears that are in geared or meshed relationship with each other. In an embodiment,third gear132aandfourth gear132bare reusable.
• Indexer or stepper motor is coupled via acoupler134, e.g., a spring-loaded coupler to increase accuracy, to a shaft holding one ofthird gear132aorfourth gear132b, here ashaft136aholdingthird gear132aandgear126a. Asecond shaft136bholds bothfourth gear132bandgear126b. Driver or gears126aand126bare illustrated as holdingextender122, shown in cross-section, which is located withinhousing124.Shafts136aand136beach extend through a wall ofhousing124 and are be held in place with respect tohousing124 via a pairreusable ball bearings138aand138bmounted tohousing124 at a desired spaced apart distance, and which provide apertures through whichshafts136aand136bextend. In the reusable embodiment ofFIGS.5 and7,control unit24 is programmed to retractextenders122 fromtubes108a,108bafter treatment to a starting position for the next treatment. Here,indexer130 is driveable in two directions.
• In the embodiment in whichhousing124, drivers or gears126aand126b, andextender122 are disposable, i.e., forFIG.6,shafts136aand136bare broken (e.g., to the right ofbearings138aand138b) into reusable and disposable sections, which are translated together upon the user installingmixing container100 and disposable set90 for treatment. The reusable and disposable sections ofshafts136aand136bmay have mating male and female sawteeth connectors that slide together to transfer torque during operation. In the disposable embodiment ofFIGS.6 and7,housing124, drivers or gears126aand126b, andextender122 are discarded after treatment.
• In a further alternative embodiment, worm gears132aand132binFIG.7 are not provided.Shaft136bheld by bearing138bis still provided and mounts driver orgear126bfor rotatable operation withextender122. Here,gear126bis not driven and follows the movement ofextender122, but nonetheless forcesextender122 against drivengear126a, which is still held in position by bearing138a, which acceptsshaft136aextending tomotor coupler134.
• Regardless of whether the embodiment ofFIG.5 or6 is used, it is contemplated forcontrol unit24 to provide a current or torque monitor that provides a signal indicative of whetherplug112 is fully abutted against the mostdistal concentrate capsule110 when mixing is to commence. Pushingplug112concentrate capsules110 throughconcentrate tubes108a,108bshould require a measurably higher torque and currant than pushingplug112 alone.Control unit24 is programmed accordingly in one embodiment to look for the higher motor current prior to starting the indexing sequence. To aid the indexing sequence, it is contemplated to provide an annular flap orprotrusion108d(FIGS.5 and6) at the proximal end ofconcentrate tubes108a,108b, which serves to holdconcentrate capsules110 in place prior to mixing and to provide a current spike as each capsule is pushed past the annular flap orprotrusion108dand into the WFI for mixing.
• Control unit24 ofdialysis system10 is programmed to cause the stepper motor orother indexer130 toindex extenders122 a preset distance one or more time during treatment to mix one or more supply of fresh dialysis fluid. Each index may cause one ormore concentrate capsule110 to be delivered to the WFI. As mentioned above, multiple dispensingactuators120a,120bmay be provided, e.g., one forindexing electrolyte capsules110 and another for indexingosmotic agent capsules110. The twoactuators120a,120bmay also be used to dispense other types ofcapsules110, such as pH buffers and diagnostic agents. Or, additional actuators120cto120nmay be provided to dispenseadditional capsules110.
• As illustrated inFIG.6, concentratecapsules110 may include anouter gel coating110aforming a sphere or spherocylinder (cylinder with semispherical ends). The gel coating may hold a powder orliquid concentrate110bdepending on the type of concentrate. The powder or liquid may have a highest possible concentration so thatcapsule110 is as small as possible. The quantity and concentration of powdered orliquid concentrate110bare selected to as to be mixed with a known volume of WFI located within thesterile mixing container100 held by theclamshell holder152 to form a desired dialysis fluid when fully mixed, e.g., a 1.5%, 2.5% or 4.25% dextrose PD solution.
• Referring again toFIG.1, control unit24 of system10 may be configured to perform the following three-part mixing sequence: (i) partially fill mixing container100 with WFI by (a) opening valves84aand84b, and with all other valves closed, using purified water pump74bof distillation unit12 to pump a first programmed amount of WFI into mixing container100 or (b) opening valves84aand84c, and with all other valves closed, using system pump actuator82 to pump a first programmed amount of WFI into mixing container100; (ii) index extenders122 of dispensing actuators120a,120bso as to push a programmed amount and type of concentrate capsules110 into the first programmed amount of WFI held within mixing container100, and with valves84band84copen, and with all other valves closed, using system pump actuator82 to vigorously recirculate the WFI and the dry or liquid concentrate from capsules110, while heating the ongoing mixture to, e.g., 37° C. to dissolve coatings110aof capsules110; and (iii) fill mixing container100 with the remainder of the designated volume of WFI by (a) opening valves84aand84b, and with all other valves closed, using purified water pump74bof distillation unit12 to pump a second programmed amount of WFI into mixing container100 or (b) opening valves84aand84c, and with all other valves closed, using system pump actuator82 to pump a second programmed amount of WFI into mixing container100, wherein the cool WFI brings the resulting dialysis fluid temperature to below, but perhaps near, 37° C. As discussed above, distillation unit12 may output heated purified water, e.g., WFI, such that heating during the recirculation in (ii) above can be minimized. Thecontrol unit24 performs the above-operations by ensuring the mixture temperature in thecontainer100 is optimal for mixing/dissolving and not too high, which could damage the concentrates. Thecontrol unit24 may set a temperature of the mixture to slightly higher than 37° C. such that the addition of cooler WFI (e.g., the second programmed amount of WFI) to thecontainer100 causes the mixture to cool to the ˜37° C. target temperature.
• It is contemplated forcontrol unit24 during the recirculation in (ii) above to causesystem pump actuator82 to reverse direction at least one time. Also, it is possible that concentratecapsules110 are larger than the inner diameters of mixing container inlet/outlet lines94band94c, so that the capsules fall to the bottom of mixingcontainer100 rather than potentially clogging one of the lines. Ascoatings110adissolve, powder or liquid concentrates110bare swept away by the WFI moving upwardly through inlet/outlet port102, carried through mixingcontainer100, and recirculated through the tubing including pumpingline92.
• As discussed above, proportioning of WFI and concentrate is performed on a volumetric basis, that is, providing the WFI and each needed concentrate in a predefined ratio to arrive at a desired dialysis fluid, e.g., 1.5%, 2.5% or 4.25% dextrose PD solution. It is also contemplated to confirm that the dialysis fluid has been mixed properly by comparing its conductivity to a known conductivity for the desired dialysis fluid. To this end, it is contemplated to pump a sample of the mixed dialysis fluid past one of the conductivity sensors ofdistillation unit12, e.g.,downstream conductivity sensor70busingpurified water pump74b, after which the sample is sent to drain76 ortank14 ofdistillation unit12. If the sample is bad the test may be repeated, and if the samples continuously fail, the entire batch within mixingcontainer100 may be delivered to drain76 ortank14 for reprocessing, all under control ofcontrol unit24.
• As mentioned above, it is contemplated to provide one or morediagnostic capsule110, which may be stored as the last capsule in an electrolyte orosmotic agent tube108aor108b(or in a separate tube), and which is inserted into a known amount of effluent or used dialysis pumped viapump actuator82 from patient P into mixingcontainer100. It is contemplated to letdiagnostic capsule110 dissolve into the effluent, after which patient P in one embodiment brings the effluent bag to a clinic for analysis. In some instances, adiagnostic capsule110 may be dispensed after every drain for collection of additional effluent data over multiple dialysis cycles.
• FIG.8 illustrates an alternative embodiment in whichsystem10 provides onsite diagnostic equipment that analyzes patient P's effluent solution. Here, after inserting the one or morediagnostic capsule110,control unit24 may cause the effluent and capsule to mix in a manner described above (may or may not be heated). Oncediagnostic concentrate110bis dispersed homogenously within the effluent, the effluent solution is analyzed.FIG.8 illustrates that in one embodiment anoptical sensor array140 is provided, which includes a plurality ofphotodiodes142 that each have discrete wavelength light sources, and which each shine through one ormore aperture144 provided in a wall ofholder152 discussed next.Optical sensor array140 may be mounted toholder152 in a same manner as, and possibly with,reusable housing124 and associated indexing equipment discussed in connection withFIG.7.
• Optical sensor array140 analyzes the effluent solution and dissolveddiagnostic capsules110 by modulating a light array across a spectrum of wavelengths through theaperture144 and measuring the incident light with the photodiode sensor array, which provides more nuanced data as opposed to white light or a color camera. Theoptical sensor array140 may use multiple wavelengths of light for varying reasons. In some instances,diagnostic capsules110 may cause a color change (e.g., for white blood cell detection, which correlates to peritonitis). In other instances, different wavelengths of light propagate differently through effluent, thereby exposing differing distortions of an aperture pattern. The use of different wavelengths of light provide an additional dimension of data that may be used to characterize changes that indicate peritonitis or other conditions of concern.Diagnostic capsules110 may for example, be formulated specifically to detect white blood cells or other markers of peritonitis, e.g., by measuring turbidity.Diagnostic capsules110 may additionally be formulated to look for urea, electrolytes, and phosphates, for example.
• ViewingFIGS.1 and8, it is contemplated thatcontrol unit24 ofsystem10 be connected to a server either directly via a modem and internet connection provided with the control unit, or via the wireless connection with patient P'ssmartphone98 employing the app that starts treatment and collects effluent sample data and forwards it to the server. The server is in turn accessed by any one or more of the providers of the system, a clinician, a doctor's office, a service portal, or a patient website. The effluent data may be tracked, e.g., by the patient's clinician or doctor, to determine the effectiveness of therapy, look for peritonitis or other patient condition needing attention, and possibly to send an updated patient prescription from the clinician or doctor, through the server, to the dialysis system to run a modified treatment.
• In some embodiments, the effluent data for a population of patients undergoing PD may be used to train a machine-learning system. In these embodiments, the effluent data is collected in addition to confirmed indications of peritonitis for the population of patients. The machine-learning system processes the effluent data and the indications of peritonitis to determine effluent patterns that are indicative of a future onset of peritonitis. After training, the machine-learning system analyzes new effluent data for patients to provide warnings if the data indicates peritonitis may occur in the near future for an identified patient.
Volume Control
• Referring now toFIGS.9 to12, an embodiment for a dialysis fluidvolume control subsystem150 ofoverall system10 is illustrated. Dialysis fluidvolume control subsystem150 provides a non-invasive measurement of volume and flowrate, which allows for any type of dialysis fluid pump to be used. From a simplicity of disposable standpoint, the most desirable pump is a peristaltic pump, which simply requires pumpingtube92 to operate with reusableperistaltic pump actuator82. Peristaltic pumps are known to be less accurate than other types of fluid pumps, such as membrane pumps, and to become less accurate over time as the peristaltic pump tubing degrades. Dialysis fluidvolume control subsystem150 allowssystem10 to be completely decoupled from the inaccuracy associated with peristaltic pumping.
• Volume control subsystem150 includes aholder152, which may be held by, mounted to, or formed integrally withhousing20.Holder152 in the illustrated embodiment is formed as a clamshell having afirst clamshell panel154 and asecond clamshell panel156.Clamshell panels154 and156 may be made of metal and/or plastic, and which may be commensurate with the material(s) ofhousing20.Clamshell panels154 and156 in an embodiment are rigid and vertically disposed and accept flexible, vertically disposed and sterilized mixing container orbag100 as discussed above for holding fresh dialysis fluid, used dialysis fluid, saline, purified water and concentrates for mixing dialysis fluid, or other medical fluids.
• As whichever fluid fills the vertically disposedbag100, the bag where the fluid is located conforms exactly (or near exactly) to the shape of vertically disposedclamshell holder152. The filling fluid also increases pressure within sterilizedbag100.Volume control subsystem150 capitalizes on the known relationship between pressure and head height. With all other dimensions of the fluid withinbag100 known due to the known dimensions of vertically disposedclamshell holder152, except for the height of fluid within the bag, solving for the head height based on a measured pressure of the fluid allowscontrol unit24 to calculate the volume of fluid inbag100 at a given time.Control unit24 also calculates a difference between head heights of two different fluid levels and divides the difference by a time between pressure measurements to determine flow rate.
• In an embodiment, one or more pressure sensor160 (see alsoFIG.1) is located at the bottom ofclamshell holder152, e.g., is fixed within an opening or mounting structure formed in the lower portion ofclamshell panel154 in the illustrated embodiment.Pressure sensor160 may include apressure pouch162 that is mounted to or intoclamshell panel154 ofclamshell holder152, whereinpressure pouch162 makes contact with the vertically disposed container orbag100.Pressure pouch162 and atransmission tube164 attached thereto hold air or other pressure transmission medium, which transfers the pressure due to medical fluid within vertically disposedbag100 to apressure transducer166, such as a load cell, strain gauge, and/or compensated microelectromechanical systems (“MEMS”) pressure sensor. Load cell orstrain gauge166 outputs a signal indicative of the pressure and thus the head height of medical fluid withinbag100 to controlunit24, which determines head height and multiplies the head height by the cross-sectional area of the clamshell to determine volume, and divides the volume over a time delta (e.g., time between pressure measurements) to determine flowrate. Two ormore pressure sensors160 may be provided, each outputting to controlunit24, for redundancy and accuracy, and to detect a malfunctioning sensor, if desired.
• In one embodiment,volume control subsystem150 is configured not to completely fill vertically disposedbag100, so that the bag does not apply pressure to the medical fluid located therein. Also, the top of the bag is not constrained byclamshell holder152 as illustrated inFIGS.9 to12 so as not to pressurize the bag. Additionally,vertical bag100 andclamshell holder152 overlap so that the liquid filled cross-sectional area is defined by the known dimensions of the clamshell holder as opposed to the welds or seams of the container or bag.
• It is contemplated to install one or moreliquid level sensor168 in or on a lower portion of apanel154 or156 ofrigid clamshell holder152 to maintain a baseline level of medical fluid withinflexible bag100. In the illustrated embodiment,liquid level sensor168 is located to align withbag100 where it just starts to angle inward from vertical. The baseline level of fluid serves multiple purposes. First, the bottom ofclamshell holder152, and thusflexible bag100 contained therein, may be angled, rounded or otherwise changing in cross-section to help direct fluid to inlet/outlet port102 or104, and so thatbag100 does not have to be formed with a flat bottom. The change in cross-section may causeflexible bag100 to not be perfectly aligned withclamshell holder152. Second, the contacting of one ormore pressure sensor160 with the bottom ofbag100 may cause misalignment between the bag and the clamshell holder. In an embodiment, the liquid below the baseline level is not taken into account in the volume or baseline determination, such that each of the discrepancies just described existing below the baseline level may be ignored. Instead, a difference in head height levels above the baseline level is used to determine an amount of fluid delivered to or removed fromflexible bag100.
• Liquid level sensor168 may for example be a non-invasive capacitive sensor that senses the level of medical fluid within flexible container orbag100 and outputs to controlunit24 as indicated by the dotted line extending therefrom. Suitable level sensors forsensor168 are disclosed in the following patent applications owned by the assignee of the present disclosure: U.S. provisional application No. 62/884,862, filed Aug. 9, 2019 and U.S. provisional application No. 62/830,906, filed Apr. 9, 2019, the contents of each of which are incorporated herein by reference and relied upon. An output fromsensor168 is triggered for example upon a patient fill (fresh dialysis fluid to patient P) or upon an effluent drain (used dialysis fluid to drain76 ortank14 of distillation unit12) when the corresponding liquid level falls to the level at whichsensor168 is positioned againstbag100. Upon the output fromsensor168 being triggered,control unit24 stops treatment and causesuser interface26 and/or speakers to issue and alarm. An alarm may alternatively or additionally be sent to patient P'ssmartphone98. The remedy to the alarm may be to take stock of how much treatment has taken place, flush all remaining fluid frombag100 to drain76 ortank14 ofdistillation unit12 and start over. In some embodiments, theliquid level sensor168 may include or be used in connection with a tilt sensor (e.g., an accelerometer). An output from the tilt sensor may be used to compensate for tilt within a certain range for level sensing. If a detected tilt exceeds a specified threshold, thecontrol unit24 may generate an alarm.
• The establishment of a baseline level viasensor168 also ensures that a fill of fresh or used dialysis fluid intoflexible bag100 is commenced with the liquid level at or above the baseline level. In an embodiment, two or more level sensors168 (seeFIG.1) are provided to establish one more warning level above the baseline level, which triggers a signal that controlunit24 uses to take evasive action prior to the fluid level reaching the baseline level. An upperbaseline level sensor168 may also be provided to ensure thatflexible bag100 does not fill completely and begin to pressurize.
• FIGS.9,11 and12 illustrate an example of a volume determination. The head height of the column of fluid inbag100 is determined by the pressure measured bypressure sensor160 divided by the density of the fluid inbag100 multiplied by the local gravity.Control unit24 stores different densities for different fluids. For example, 0.9% saline is 1.005 g/ml versus water, which is 1.000 g/ml. Saline therefore produces a slightly higher pressure than water per unit height. Likewise, different fresh dialysis fluids may have different densities, which are stored atcontrol unit24. The density of effluent dialysis fluid may be patient specific, and it is therefore contemplated to determine same on a patient-by-patient basis for entry intocontrol unit24. When preparing dialysis fluid,control unit24 uses different densities at different times as purified water, e.g., WFO, is mixed with concentrate100bto form dialysis fluid.
• InFIG.9,bag100 is full, no fluid has been delivered and the pressure of fluid as measured bypressure sensor160 and outputted to controlunit24 is 3000 Pascals. InFIG.11,bag100 is partially full and the measured pressure as measured bypressure sensor160 and outputted to controlunit24 has dropped to 1518 Pascals, a 1482 Pascal (0.22 psig) change, which corresponds to a 15.2 cm (6 inch) drop in head height. That distance multiplied by the known and constant cross-sectional area withinbag100, as created byclamshell holder152, results in a 0.50 liter of fluid being delivered (as indicated by user interface26) to patient P,tank14 ofdistillation unit12 ordrain76. InFIG.12,bag100 is mostly empty (but still above baseline as set by level sensor68) and the measured pressure as measured bypressure sensor160 and outputted to controlunit24 has dropped to 35 Pascals, an overall 2965 Pascal (0.43 psig) change, which corresponds again to a 15.2 cm (6 inch) drop in head height. That distance multiplied by the known and constant cross-sectional area withinbag100, as created byclamshell holder152, results in an additional 0.50 liter of fluid being delivered to patient P,tank14 ofdistillation unit12 ordrain76, as indicated byuser interface26.
• InFIG.12, the remaining 35 Pascals of pressure is due to the remaining fluid residing in the funnel or changing cross-sectional area ofbag100 andclamshell holder152. As discussed above, it is contemplated to stop depleting fluid frombag100 prior to the fluid level dropping into the funnel area and to providelevel sensor168 as a backstop to ensure that the fluid level does not fall into the funnel area. The subsequent drain of patient P and filling ofbag100 begins at the 35 Pascals of pressure and builds to a pressure corresponding to a prescribed drain volume, e.g., fill volume+fill volume*(0.07) to take into patient P's ultrafiltration. In the above example, the drain volume would be two liters plus two liters*(0.7) or 2.14 liters.Control unit24 in the example drains patient P until obtaining a pressure reading frompressure sensor160 of a pressure corresponding to 2.14 liters above 35 Pascals.
• In an embodiment after the patient drain, all fluid withinbag100, including the remaining fluid corresponding to the 35 Pascal pressure is removed to drain76 ortank14 of distillation unit. The above procedure is then repeated. It is accordingly contemplated to formulateconcentrate capsules110 to make more than the prescribed fill volume's worth of fresh dialysis fluid to allow (i) the changing head height evaluations discussed above to occur in the constant cross-sectional area portion ofbag100 andholder152 and (ii) fluid fordisposable set90 to be primed with fluid for recirculation and mixing.
• In any of the changing head height evaluations discussed above, instantaneous flowrate may be measured at any time during fluid flow by taking first and second pressure measurements, determining the volumes corresponding to the pressure measurements, and dividing by the time between the measurements. Flowrate is controlled by adjusting the speed ofpump actuator82 in one embodiment
• As discussed herein, dialysis fluidvolume control subsystem150 allows for a relatively inaccurate but simpleperistaltic pump actuator82 to be used. In an alternative embodiment illustrated in connection withFIG.13, a low cost gravity fedsystem250 is provided that does not use a pump, but instead, under computerized control of afresh valve252 viacontrol unit264, allows fresh fluid to flow from a freshflexible bag254 held within a fresh fluid clamshell holder256 to patient P for treatment via apatient line258, and used fluid to flow from patient P, under computerized control of usedvalve260 viacontrol unit264, to a usedflexible bag266 held within a usedfluid clamshell holder268. Fresh and usedfluid clamshell holders256 and268 and correspondingflexible bags254 and266 operate just as described above, except that they are one-way with fluid only flowing out or into containers orbags254 and266. Fresh fluid clamshell holder256 andflexible bag254 allowcontrol unit264 to monitor volume and flowrate of fresh dialysis fluid to patient P. Usedfluid clamshell holder268 andflexible bag266 allowcontrol unit264 to monitors volume and flowrate of used dialysis fluid removed from patient P. The difference between the two is the patient's ultrafiltration (“UF”) removal.
Inline Heating
• Referring now toFIGS.14 to16, various embodiments of aninline heater180 are illustrated.Inline heater180 is illustrated inFIG.1 as being located betweenpump actuator82 and patient P to heat the dialysis fluid flowing through cylindrical heating and pumpingtube92 to patient temperature, e.g., 37° C., prior to delivery to the patient. As discussed previously, dialysis fluid enteringinline heater180 may be preheated to close to patient temperature be either one or both of (i) heating due todistillation unit12 or (ii) heating during dialysis fluid mixing. In any case,inline heater180 is also capable of heating the dialysis fluid from ambient temperature to body temperature.
• Inline heater180 in the illustrated embodiment is an inductive heater having aninductive coil182 within which the disposable component of the heater is disposed, wherein the disposable component, like that of pump, is a single tube or a tube that is folded or provided with a fitting such that the tube reversesdirection 180 degrees. Tube92 (FIG.14), or eachleg92aand92bof the dual tube (FIG.15), is provided with a susceptor184 (FIG.14) orsusceptors184a,184b(FIG.15), which may be any medically safe material having the ability to absorb electromagnetic energy and convert the energy to heat. In an embodiment,susceptors184,184a,184bare made of a medically safe material that exhibits properties of an efficient susceptor, such as 400 series stainless steel, 18-0 magnetic stainless steel, titanium, and combinations and alloys thereof.Susceptors184,184a,184bmay have a smooth contour to limit their effect on pressure drop in heating andpumping line92, a changing countour, e.g., mesh or brillo pad, to increase surface area contact with the fluid to be heated, or a combination of both. In a further alternative embodiment,susceptors184,184a,184bmay be made of a twisted strip of metal, which increases surface area contact and contact time without creating undue pressure drop along heating and pumpingtube92.
• Tube92 andtube segments92a,92b(FIG.15) includingsusceptors184,184a,184bare fitted within aninductive coil182, which may be a conductive copper coil.Copper coil182 is located withinhousing20 of the dialysis machine and is covered by a plastic (or other material that is not heated by the energized coil)machine panel20 havingguides20a(FIG.14), and20b(FIG.15), so that a user cannot accidently touchcoil182.Inductive coil182 is connected electrically topower electronics190, which may include aresonant circuit192 anddriver electronics194.Driver electronics194 operate under the control ofcomputerized control unit24, which causes power to be supplied toresonant circuit192 andinduction coil182 when needed, e.g., when fresh dialysis fluid is flowing to patient P, or when WFI and concentrate110bare being recirculated for mixing, and when feedback from one or more dialysis fluid temperature sensor indicates to controlunit24 that fluid heating is needed.
• Resonant circuit192 in an embodiment is an LC circuit that oscillates at its natural resonant frequency.Resonant circuit192 includes acapacitor192athat stores energy in an electric field (F) between its plates, which depends on a voltage across its plates, and aninductor192b, which stores energy in its magnetic field (B), which depends on a current through the magnetic field.Driver electronics194 induces a voltage acrossinductor192b, which causes a current to chargecapacitor192awith a voltage.Charged capacitor192ain turn powersinductive coil182, which in turn induces a current insusceptors184,184a,184b, causing the susceptors to heat and transfer heat to the fluid flowing withintubes92,92a,92b.
• In an embodiment, anupstream temperature sensor186ais mounted tomachine housing20 and is located so as to sense the temperature of cool (or cooler) dialysis fluid (or mixing WFI and concentrate110b) upstream ofsusceptor184 orsusceptors184aand184b. Adownstream temperature sensor186bis mounted tomachine housing20 and is located so as to sense the temperature of heated dialysis fluid (or mixing WFI and concentrate110b) downstream ofsusceptor184 orsusceptors184aand184band heading to patientP. Temperature sensors186aand186bmay be non-contact (e.g., thermopile) sensors, so that there is no invasive or direct fluid contact.Control unit24 uses the temperature sensor feedback and controls power to theresonant circuit192 andinductive coil182 using on/off control, proportional-integral-derivative (“PID”) control, fuzzy logic control and combinations thereof. In an embodiment, the power supplied to the power electronics is around one kilowatt.
• In some embodiments, power for theinductive coil182 can be determined using a flow rate and an initial temperature of fluid flowing within pumpingtube92 or withinflexible bags254 and266 using, for example, a thermistor (e.g., theupstream temperature sensor186a). For example, 100 watts applied by theinductive coil182 may raise a temperature of fluid flowing at a rate of 100 ml/minute by 1° C. In this example, to raise the fluid temperature by 5° C., 500 watts would have be applied. This relation between flow rate and initial temperature may depend on a cross-sectional area of thetube92 being known and fixed.
• Inductiveinline heater180 is in general a safe system during use.Susceptors184,184a,184b, in an embodiment, increase in temperature only a few degrees above the target temperature, e.g., 37° C., and are cooled immediately by the dialysis fluid (or WFI mixing withconcentrate110b). Likewise, the temperatures of thetube92 carrying susceptor184 (FIG.14) ortubes92aand92bcarryingrespective susceptors184aand184b(FIG.15) do not heat appreciably higher than the target temperature.Temperature sensors186aand186bhave been found to operate well when positioned more than 12.5 mm (one-half inch) fromtubes92,92a,92bcarrying the fluid to be sensed. Close and precise positioning ofdisposable tubes92,92a,92bwith respect to the temperature sensors is therefore not overly critical. The inductive, inline heating ofheater180 of the present disclosure is advantageous for at least one reason including: being non-invasive or non-contact, having a quick heating response time, operating with a low cost and space saving disposable, having a high power coupling resulting in efficient heating, using lower cost electronics, control and sensing, and heating accurately.
• Referring specifically toFIG.14,inductive heater180 includesinductive coil182 within which heating and pumpingtube92 is inserted for operation. Heating and pumpingtube92 in which susceptor184 is located may have an inner diameter of from about 4.00 mm (0.16 inch) to about 12.7 mm (0.50 inch).Temperature sensor186ais located upstream frominductive coil182 andsusceptor184, whiletemperature sensor186bis located downstream frominductive coil182 andsusceptor184.Temperature sensors186aand186boutput to controlunit24, which also controlspower electronics190 havingresonant circuit192 anddriver electronics194.
• FIG.14 further illustrates thattemperature sensors186aand186bare mounted inhousing20 so as to extend from the housing towards heating and pumpingtube92. In the illustrated embodimentinductive coil182 is located withinhousing20 on the other side of the housing wall fromtube92 so that patient P cannot touch the coil. Again, the housingwall separating coil182 andtube92 is made of a material, e.g., plastic, that does not affect the magnetic field created by the coil.Housing20 in the illustrated embodiment is provided with standoffs or guides20athat define apertures large enough for a patient connector200 (discussed next) connected to the end ofpatient line94dto pass through. It should be appreciated that the standoffs or guides20amay be optional since centering thetube92 within thecoil182 may not be critical or needed.
• When patient P or a caregiver has inserted heating and pumpingtube92 throughhousing20 to the point that susceptor184 is roughly centered withininductive coil182,collars92dlocated ontube92 come into registration with the apertures defined byguides20a. In the illustrated embodiment,tube92 is slid from left to right.Collar92dto the right is accordingly configured so that it can slide through the aperture ofguide20ato the left.Collar92dto the left however is provided with a flanged backstop and/or adetent92e, which provides visual and/or tactile feedback that susceptor184 is roughly centered withininductive coil182 and tends to hold heating and pumpingtube92 in that position during treatment.Guides20aare also located neartemperature sensors186aand186bso that pumping and heating tube is maintained a desired distance from the temperature sensors, e.g., at least 12.7 mm (0.5 inch). It should be appreciated thatcoil182 and the opening inhousing20 may be oriented horizontally as illustrated or vertically if desired. If vertically, heating and pumpingtube92 may be inserted intohousing20 upwardly or downwardly.
• Referring specifically toFIG.15,inductive heater180 includesinductive coil182 within which heating andpumping tubes92aand92bare inserted for operation. Heating andpumping tubes92aand92bin which susceptors184aand184bare respectively located may have an inner diameter of from about 4.00 mm (0.16 inch) to about 12.7 mm (0.50 inch).Temperature sensor186ais located upstream frominductive coil182 andsusceptors184aand184b, whiletemperature sensor186bis located downstream frominductive coil182 and the susceptors.Temperature sensors186aand186boutput to controlunit24, which also controlspower electronics190 havingresonant circuit192 anddriver electronics194.
• FIG.15 further illustrates thattemperature sensors186aand186bare mounted inhousing20 so as to extend from the housing towards heating andpumping tubes92aand92b, respectively, and be spaced apart from the pumping tube a desired distance, e.g., at least 12.7 mm (0.5 inch). In the illustrated embodiment,inductive coil182 is located withinhousing20 on the other side of the housing wall fromtubes92aand92bso that patient P cannot touch the coil. Again, the housingwall separating coil182 andtubes92aand92bis made of a material, e.g., plastic, that does not affect the magnet field created by the coil.Housing20 in the illustrated embodiment is provided with at least one standoff or guide20bthat holdstubes92aand92bin a desired position. In the illustrated embodiment, standoff or guide20bis configured with an indentation or cutout sized and shaped to accept and holdconnector92c, connectingheating tubes92aand92b.
• Guide20bholds one end ofsusceptors184aand184bin place relative toinductive coil182. A locatingflange92fis provided withheating tubes92aand92bto hold the other ends ofsusceptors184aand184bin place relative toinductive coil182. Locatingflange92fis advantageous because it can also spaceheating tubes92aand92ba desired distance apart from one another such that the tubes remain substantially parallel as illustrated inFIG.15. However, locatingflange92fis disposable along withheating tubes92aand92b, adding to disposable cost. Therefore, a second standoff or guide, similar toguides20ainFIG.14, may be provided alternatively at the opposite end ofsusceptors184aand184bto holdtubes92aand92b. InFIG.15 the user insertsheating tubes92aand92buntil they dead end againstguide20b, which may be an easier insertion thaninductive heater180 ofFIG.14. As withFIG.14,coil182 and the opening inhousing20 may be oriented horizontally as illustrated or vertically if desired. If vertically, heating andpumping tubes92aand92bmay be inserted intohousing20 upwardly or downwardly.
• FIG.16 illustrates an output from a prototype inductiveinline heater180 using the components discussed above.
Self-Priming Patient Connector
• Referring toFIG.1, prior to delivering dialysis fluid to patient P, disposable set90, and most importantlypatient line94d, is primed so that air is not delivered to patient P and volumetric accuracy is not compromised. Known priming typically involves manual steps and cognitive thought that may tax certain patients and make the therapy less appealing. The present disclosure sets forth apatient line connector200 that, once connected to the patient's transfer set96, self-primes and then opens to allow dialysis fluid to be delivered to and removed from patient P. The patient does not have to handleconnector200 during the priming operation in one embodiment other than connecting transfer set96.
• FIGS.17 to20 illustrate one embodiment of a self-primingpatient connector200 of the present disclosure, which includes ahousing202 having afluid inlet204 connected topatient line94dand afluid outlet206 connected to the patient's transfer set96.Housing202 may be made of any suitable medical grade material, e.g., medical grade plastic, such as polyvinyl-chloride (“PVC”) or suitable medical grade non-PVC material.Housing202 inFIGS.17 and18 also includes a plastic membrane or seal208 initially coveringoutlet206 and avalve housing210 definingopenings212a,212b,212c,212d. . .212n, where opening212ais covered by a hydrophobic (air passing but liquid retaining)membrane214.Solid seal208 may, for example, be made of a polyvinylidene chloride (“PVDC”), e.g., approximately, 0.01 mm thick, whilehydrophobic membrane214 may for example be made of a 0.2 micron polytetrafluoroethylene (“PTFE”) material.Seal208 andmembrane214 may, for example, be ultrasonically sealed tohousing202 andhousing210, respectively.
• Acheck valve216 is provided, which includes aspring216a(e.g., plastic or stainless steel) and astopper216b, whereinspring216ais compressed between opposing walls ofhousing210, so thatstopper212bunder atmospheric or negative pressure, e.g., a patient drain, as illustrated inFIG.17, prevents air from enteringhousing202 viahydrophobic membrane214.FIG.18 illustrates that under positive pressure during priming,spring216ais compressed andcheck valve216 opens, allowing the priming fluid, e.g., fresh dialysis fluid, to push air out ofpatient line94dandpatient connector200, through hydrophobic membrane or vent214, throughvalve housing210 andapertures212ato212c, to atmosphere.Hydrophobic membrane214 allows the air to pass to atmosphere in a sterile manner so that the safety of patient P is not compromised. Once no more air resides withinpatient line94dorconnector housing202,hydrophobic membrane214 becomes wetted with the priming fluid (e.g., fresh dialysis fluid), which prevents the fluid from passing through the membrane, such that pressure builds withinpatient line94dandconnector housing202, whereinhousing outlet206 is blocked viahydrophobic membrane214 andsolid seal208.
• In an embodiment,spring216ais selected such that a relatively small amount of air pressure, e.g., less than 0.5 psig, is able to compress the spring to release air frompatient connector200. In the illustrated embodiment ofFIG.19, the material and/or thickness ofsolid seal208 are selected so that the seal ruptures open under the pressure that builds after all (or substantially all) of the air inpatient line94dandpatient connector housing202 has been vented throughhydrophobic membrane214. It is contemplated thatsolid seal208 is configured in one embodiment to rupture at around 5 psig, leaving a healthy delta, e.g., on an order of magnitude, between thespring216aopening pressure and thesolid seal208 rupturing pressure. The difference provides a robust and repeatablepatient connector200.Seal208 may be provided with score lines or grooves of narrowed thickness (not illustrated), so that the solid seal ruptures in a uniform and repeatable way. For example, the score lines may form and X or cross, which tends to rupture at the junction of the score lines and then tear along the score lines outwardly towards a cylindrical wall ofhousing202.
• Theseal208 may include, for example, a thin film polymer such as polyvinylidene chloride (“PVCD”) or high-density polyethylene (“HDPE”). Theseal208 may alternatively include a thick film that dissolves on contact with dialysis fluid, such as polyvinyl acetate (“PVAC”) on a plastic scaffold or polyvinyl alcohol (“PVA”) without a scaffold. Theseal208 may further include a soluble glucose/dextrose film on a plastic scaffold that dissolves on contact with dialysis fluid. In further embodiments, theseal208 may include a reactive material (e.g., an alkali metal) on a thin film polymer. The reactive material reacts with dialysis fluid upon breaching the thin film polymer.
• InFIG.19, withhydrophobic membrane214 fully wetted, no pressurization can occur through the membrane tovalve housing210.Spring216aaccordingly decompresses, pressingstopper216bagainstpatient connector housing202. Fluid pressure withinpatient connector housing202 builds, reaching the rupturing pressure of solid seal208 (e.g., about 5 psig), causing same to open. Thereafter, fresh dialysis fluid may flow to patient P, while used dialysis fluid may be removed from patient P. As discussed herein, the first step of a peritoneal dialysis treatment is often to drain effluent from the patient due to a last fill from a previous treatment or day exchange. Here, fresh dialysis fluid is used to reach the opened seal condition ofFIG.19, after which used dialysis fluid is removed from patient P, pushing the priming fluid in the other direction towardsdrain76 orstorage tank14 ofdistillation unit12.
• FIG.20 illustrates an alternative embodiment in which a cuttingmember218 is provided, which is not moved under air pressure (e.g., less than 0.5 psig) while air is being purged throughhydrophobic membrane214, but is moved after the air has been purged fromconnector housing202 and upon the building of fluid pressure (e.g., about 5 psig) trapped in part byhydrophobic membrane214 andsolid seal208. Cuttingmember218 in the illustrated embodiment is in the form of acylinder218athat tapers to aspike218bmade of a resilient and low coefficient of friction material, such as teflon, and which is confined to translate withinpatient connector200 over a short distance that is enough to puncture and tear the solid seal. In the illustrated embodiment, cuttingmember218 causes the puncture to occur along the outer rim ofsolid seal208, so that a tear subsequently takes place along taperingcylinder218aas it translates through the seal. In an embodiment, a portion ofseal208 remains attached topatient connector200, so that the seal is not carried to an undesirable place and so that the seal does not inadvertently reseal theoutlet206 ofpatient connector200 closed.
• FIG.21 illustrates an alternative self-primingpatient connector200 of the present disclosure, which may be used with either theruptured seal208 embodiment ofFIG.19 or the punctured or cutsolid seal208 embodiment ofFIG.20.Patient connector200 includes an outercylindrical housing220 that is perforated or provided with a series ofholes222 that allow air to be vented frompatient line94dandpatient connector200 under positive pressure from the priming fluid.Cylindrical housing220 may be made of PVC, non-PVC, PTFE, or other suitable medical grad plastic. Alternative hydrophobic membrane224 (e.g., PTFE) is also provided as a cylinder having an outer diameter that fits snugly within an inner diameter of perforatedouter housing220. Analternative check valve226 is provided in the form of an elastomeric sleeve, which is stretched so as to be compressed over the outside ofouter housing220, covering the series ofholes222 whenpatient connector200 is placed under atmospheric or negative pressure. Under positive air pressure,elastomeric sleeve226 is stretched open to allow air vented throughhydrophobic membrane224 and the series ofholes222 to escape to atmosphere. When negative pressure is applied topatient line94d, e.g., for draining patient P,elastomeric sleeve226 is press-fit due to its elastic nature and sucked under the negative pressure (assumingmembrane224 is not wetted) to the outside ofouter housing220, coveringholes222.
• In the illustrated embodiment,cylindrical housing220 includes aninlet220aand anoutlet220b.Inlet220a(upper right inFIG.21) oroutlet220b(lower left inFIG.21) is initially covered or sealed viasolid seal228, e.g., ultrasonically welded tohousing220, which may be scored or grooved as described above for the rupture embodiment. Cuttingmember218 in the form of acylinder218athat tapers to aspike218bmay or may not be provided.Patient connector200 ofFIG.21 operates at least substantially the same as described above forconnector200 ofFIGS.17 to20. Priming fluid delivered throughpatient line94dpressurizes air in the patient line andconnector200 to, e.g., less than 0.5 psig, which is enough to expand elastomericcheck valve sleeve226, allowing air to escapepatient connector200 to atmosphere viahydrophobic membrane224 and holes222. When all or substantially all of the air has been purged fromconnector200,hydrophobic membrane224 becomes wetted such that pressurization throughhydrophobic membrane224 ceases and elastomericcheck valve sleeve226 returns to its unstretched position, coveringholes222. The fresh dialysis fluid builds in pressure to, e.g., about 5 psig, after which either (i)solid seal228 configured to rupture ruptures or (ii) cuttingmember218 is translated to cut and opensolid seal228. Fresh and used dialysis fluid may then flow in either direction throughpatient connector200.
• In an alternative implementation of thepatient connector200 ofFIG.21, if cylindricalhydrophobic membrane224 is sufficiently rigid and is able to be connected sealingly to solid plastic inlet and outlet tubes, ports, etc., thencylindrical housing220 may be eliminated, such that elastomericcheck valve sleeve226 fits sealingly directly ontohydrophobic membrane224. Elastomericcheck valve sleeve226 here compresses ontomembrane224 to prevent air from enteringpatient connector200 under atmospheric and negative pressures.
• FIGS.22 to24 illustrate a further alternative implementation of self-primingpatient connector200 of the present disclosure, which is not used with a ruptured or cutsolid seal208 or228.Housing202,connector inlet204,connector outlet206,check valve housing210,hydrophobic membrane214 andcheck valve216 inFIGS.22 to24 include all of the structure, functionality and alternatives described above.Patient connector200 ofFIGS.22 to24 includes first andsecond members232 and234 that are hinged to an inner wall ofhousing202.Members232 and234 are also each spring biased, e.g., with a stainless steel or medically safeplastic spring236, wherein springs236 are themselves hinged toconnector housing202 and are each initially pulled apart and thus biased to close and to rotate theirrespective member232 and234 along its hinge point.Members232 and234 are also initially latched together as illustrated inFIG.22 in a manner preventing the springs from rotating the first and second members.Member234 inFIG.22 is positioned to block dialysis fluid flow intoconnector outlet206 and patient P's transfer set96. The latching ofmembers232 and234 forms a latchedmember234 and a latchingmember236.
• InFIG.22, air is vented through andhydrophobic membrane214,check valve216 andvalve housing210 to atmosphere as described above, such that all or most all air frompatient line94dmay escape during priming whenpatient line94dis placed under positive pressure. Air is prevented from entering thepatient connector200 andline94dwhen placed under negative pressure. The pressure inpatient connector200, e.g., less than 0.5 psig, while air is being vented throughhydrophobic membrane214 is not enough to rotate latchedmember234 so as to come free from latchingmember232. However, inFIG.23, when the priming fluid, e.g., fresh dialysis fluid, reaches and wetshydrophobic membrane214, the pressure in the patient connector increases enough, e.g., to about 5 psig, to release latchedmember234 from the latchingmember232.FIG.24 illustrates that aftermembers232 and234 are unlatched, both members are thereafter rotated via the stretched springs236, returning to their unbiased positions.Members232 and234 remain in the rotated open positions regardless of whether they are thereafter placed under positive or negative fluid pressure to allow dialysis fluid to flow in either direction throughpatient connector200 and transfer set94. As illustrated inFIGS.22 to24,solid seal208 or228 is not used.
• In an alternative embodiment, springs236 are removed and latchingmember232 and latchedmember234 are replaced by a bendable, e.g., plastic, latching member and a bendable, e.g., plastic, latched member. The bendable latching member is bent to place a mechanical force on the bendable latched member, bending the latched member to closeconnector outlet206 in a manner illustrated inFIG.22. The latched member may be provided with a foam or otherwise compressible sealing head that sealsconnector outlet206 closed. The pressure inpatient connector200, e.g., less than 0.5 psig, while air is being vented throughhydrophobic membrane214 is not enough to compress the compressible sealing head, so that the bendable latched member does not come free from the bendable latching member. However, when the priming fluid, e.g., fresh dialysis fluid, reaches and wetshydrophobic membrane214, the pressure in the patient connector increases enough, e.g., to about 5 psig, to compress the compressible sealing head enough to release the bendable latched member from the bendable latching member. Upon unlatching, the bendable latching member, biased to unbend and return to a straight shape, unbends and returns to its straight shape. With bendable latching member completely out of the way, bendable latched member, biased to unbend and return to a straight shape, unbends and returns to its straight shape, openingconnector outlet206 for dialysis fluid flow in either direction.
• Patient connectors200 of the present disclosure reduce the manual effort involved with priming.Connectors200 also remove a potential source of contamination.Patient connectors200 also eliminate or reduce spillage associated with current priming techniques. Patient P is allowed the freedom to connect to patient line24dwhenever the patient desires instead of being tied to a sequence of priming steps. Indeed, it is contemplated forsystem10 that with the peritoneal dialysis app provided on patient P'ssmartphone98, patient P may load set90 onto the machine ofsystem10, make sure enough tap water is present intank14 ofdistillation unit12, connectpatient line94dtopatient connector200, and then lie in bed and begin treatment using the peritoneal dialysis app.
Dialysis Fluid Regeneration
• Referring again toFIG.1, it is contemplated forsystem10 to regenerate and reuse used dialysis fluid removed from patient P. In the version ofsystem10 inFIG.1, after a patient dwell,control unit24 causesvalves84dand84bto be open and with all other valves closed,run pump actuator82 in a reverse direction to pull used dialysis fluid from patient P, through patient transfer set96,patient connector200,patient line94d, pumping andheating line92, and inlet/outlet line94binto mixingbag100. When patient P is fully drained,control unit24 causes dialysis fluidvolume control subsystem150 to determine the volume of the patient drain, which is stored to later determine an overall amount of ultrafiltration removed for the treatment.
• After the drain volume measurement,control unit24 causesvalves84band84eto be open and with all other valves closed,run pump actuator82 in a forward direction to pull used dialysis fluid from mixingbag100, through inlet/outlet line94c, and returnline94etotank14 ofdistillation unit12. Once insidedistillation unit12, the patient effluent is boiled and condensed into purified water, e.g., WFI, which is sent to mixingbag100 for mixing with one ormore concentrate capsule110 to form a prescribed formulation of peritoneal dialysis fluid as has been described herein. The above cycle is repeated as many times as prescribed, and wherein a final patient fill may be left within patient P as a last fill, removed totank14 ofdistillation unit12, or delivered to drain76.
• Referring now toFIG.25, in an alternative regeneration and reuse embodiment,system10 is modified so as to have a dedicated drain container orbag100d, which is placed in fluid communication with pumping andheating line92 via a drain container line94f, which is selectively opened and closed by avalve84f, such as a normally closed solenoid pinch valve under control ofcontrol unit24. Here,drain bag100doperates with its own dialysis fluidvolume control subsystem150 havingpressure sensor160 and one ormore level sensor168, each outputting to controlunit24. Mixingbag100 becomes a dedicated fresh dialysis fluid bag.
• In the version ofsystem10 inFIG.25, during a patient dwell under control ofcontrol unit24,distillation unit12 prepares a next batch of purified water, e.g., WFI, which is delivered via any of the fluid pathways described herein to mixingbag100. The WFI is mixed with at least oneconcentrate capsule110 and heated in the recirculation loop as described herein to form fresh dialysis fluid at close to patient temperature, which is stored in mixingbag100 until the patient dwell is complete. Patient dwells may last on the order of two hours, which provides adequate time to distill and condense the WFI and mix and heat one to 2.5 liters of fresh dialysis fluid, a typical patient fill range.
• After the patient dwell,control unit24 causesvalves84dand84fto be open and with all other valves closed,run pump actuator82 in a reverse direction to pull used dialysis fluid from patient P, through patient transfer set96,patient connector200,patient line94d, pumping andheating line92, and drain container line94fintodrain bag100d. When patient P is fully drained,control unit24 causes dialysis fluidvolume control subsystem150 operating withdrain bag100dto determine the volume of the patient drain, which is stored atcontrol unit24 to later determine an overall amount of ultrafiltration removed for the treatment.
• When patient P is fully drained,control unit24 also causesvalves84band84dto be open and with all other valves closed,run pump actuator82 in a forward direction to push a next prescribed fill volume's worth of fresh dialysis fluid through inlet/outlet line94b, pumping andheating line92 whereinline heater180 heats the fresh dialysis fluid to patient temperature, throughpatient line94d, self-primingconnector200 and transfer set96, to patient P to begin a next dwell period. Dialysis fluidvolume control subsystem150 operating with mixingbag100 determines the volume of the subsequent patient fill, which is stored incontrol unit24 to show that the prescribed treatment has been followed and to later determine an overall amount of ultrafiltration removed for the treatment.System10 inFIG.25 accordingly wastes virtually no time between when patient P is fully drained of effluent and when the patient begins to receive the next fill.
• After the drain volume measurement atdrain bag100d,control unit24 causesvalves84fand84eto be open and with all other valves closed,run pump actuator82 in a forward direction to pull used dialysis fluid fromdrain bag100d, through drain container line94f, and returnline94etotank14 ofdistillation unit12. Once insidedistillation unit12, the patient effluent is boiled and condensed into purified water, e.g., WFI, which is sent to nowempty mixing bag100 for mixing with one ormore concentrate capsule110 to form a prescribed formulation of peritoneal dialysis fluid as has been described herein. The above cycle is repeated as many times as prescribed, wherein a final patient fill may be left within patient P as a last fill, removed totank14 ofdistillation unit12, or delivered to drain76.
• The regeneration of used dialysis fluid has a number of advantages compared to sending all used dialysis fluid to thedrain bag100d. For instance, regeneration reduces the amount of total water consumed, and may eliminate the need for an online water source. This enables therapy water to be independent from (or minimally dependent on) external water sources. This also reduces the amount of disposables and consumables used such that consumables are only primarily used for the concentrates. Further, regeneration is safe for a patient because source water from a peritoneal cavity is by definition safe to put back into the patient since it was already there. Additionally, effluent does not have to be cleaned to a high degree to provide effective therapy (e.g. 95% effective cleaning will result in about 5% longer therapy to reach the same dialysis adequacy Kt/V (clearance*time/body water volume)). Moreover, waste can be concentrated to minimize disposal frequency (e.g., ˜2.1 kilograms/week).
• Referring now toFIG.26, in another alternative regeneration and reuse embodiment,system10 is modified so as to be able to pump effluent fluid from patient P directly totank14 ofdistillation unit12. To do so, returnvalve84eand returnline94eare moved to the other side ofpump actuator82 along pumping andvalving line92. The move allowscontrol unit24 to causepump actuator82 to pump effluent directly from patient P totank14. It should be appreciated that the move ofreturn valve84eand returnline94eto the other side ofpump actuator82 could also be made forsystem10 inFIGS.1 and25 if desired. Another modification is the addition of a structure for determining the volume or amount of effluent removed from patient P, which is located somewhere alongpatient line94d, pumping andvalving line92,return line94e, and/or within distillation unit. For example, one or more flowmeter (not illustrated) outputting to controlunit24 may be located so as to operate with any ofpatient line94d, pumping andvalving line92,return line94e, wherein the control unit integrates the flowrate signal over the course of the drain to determine total drain volume.
• Another option is to place a weigh scale230 withinhousing20 in a manner so as to weigh the contents withinstorage tank14 ofdistillation unit12. Weigh scale230 may for example be placed beneathstorage tank14. Or,storage tank14 may hang from weigh scale230. Weigh scale230 weighs the difference in weight of fluid contained withinstorage tank14 before and after the patient drain and therefore does not have to be empty at the beginning of the drain. Weigh scale230 outputs an effluent weight signal to controlunit24, which converts the weight to a volume knowing the density of the effluent, so that the drain volume may be used in the overall ultrafiltration volume calculation. It should be appreciated that weigh scale230 is useful for reasons other than determining drain volume. Weigh scale230 may also be used withcontrol unit24 and user interface26 (and/or smartphone98) to inform patient P how much tap water needs to be added totank14 at the beginning of treatment, e.g., so that there is enough fluid withinstorage tank14 to prepare a first batch of purified water, e.g., WFI, for a first patient fill, and a second batch of purified water, e.g., WFI, for a second patient fill while waiting for a first patient dwell to be completed.
• In the version ofsystem10 inFIG.26, during a patient dwell under control ofcontrol unit24,distillation unit12 prepares a next batch of purified water, e.g., WFI, which is delivered via any of the fluid pathways described herein to mixingbag100. The WFI is mixed with at least oneconcentrate capsule110 and heated in the recirculation loop as described herein to form fresh dialysis fluid at close to patient temperature, which is stored in mixingbag100 until the patient dwell is complete.
• After the patient dwell,control unit24 causesvalves84dand84eto be open and with all other valves closed,run pump actuator82 in a reverse direction to pull used dialysis fluid from patient P, through patient transfer set96,patient connector200,patient line94d, pumping andheating line92, and returnline94eintostorage container14 ofdistillation unit12.Control unit24 in one embodiment uses one or more flowmeter (not illustrated) operating with any ofpatient line94d, pumping andvalving line92, and/or returnline94eto integrate the drain volume over the course of the patient drain, which is stored atcontrol unit24 to later determine an overall amount of ultrafiltration removed for the treatment. In another embodiment, after patient P is fully drained,control unit24 receives a weight difference signal from weigh scale230 (difference in weight before and after the patient drain) and uses the drain weight to determine drain volume, which is stored atcontrol unit24 to later determine an overall amount of ultrafiltration removed for the treatment.
• When patient P is fully drained,control unit24 also causesvalves84band84dto be open and with all other valves closed,run pump actuator82 in a forward direction to push a next prescribed fill volume's worth of fresh dialysis fluid through inlet/outlet line94b, pumping andheating line92 whereinline heater180 heats the fresh dialysis fluid to patient temperature, throughpatient line94d, self-primingconnector200 and transfer set96, to patient P to begin a next dwell period. Dialysis fluidvolume control subsystem150 operating with mixingbag100 determines the volume of the subsequent patient fill, which is stored incontrol unit24 to show that the prescribed treatment has been followed and to later determine an overall amount of ultrafiltration removed for the treatment.System10 inFIG.26 also wastes virtually no time between when patient P is fully drained of effluent and when the patient begins to receive the next fill.
• Once insidedistillation unit12, the patient effluent is boiled and condensed into purified water, e.g., WFI, which is sent to nowempty mixing bag100 for mixing with one ormore concentrate capsule110 to form a prescribed formulation of peritoneal dialysis fluid as has been described herein. The above cycle is repeated as many times as prescribed, wherein a final patient fill may be left within patient P as a last fill, removed totank14 ofdistillation unit12, or delivered to drain76.
• It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims. For example, whilepump actuator82 is described as being a peristaltic pump actuator,pump actuator82 may alternatively be a volumetric pump actuator, membrane pump actuator, platen pump actuator, or other type of pump actuator.

Claims (20)

1: An inductive dialysis fluid heater comprising:

a cylindrical tube including an inner diameter from 4.00 millimeters (“mm”) to 12.7 mm;

a susceptor located within the cylindrical tube;

an inductive coil extending around the cylindrical tube in a non-contacting arrangement; and

power electronics in electrical communication with the inductive coil and configured to supply an electrical current to the inductive coil, causing the susceptor to heat.

2: The heater ofclaim 1, wherein the power electronics include a resonant circuit.

3: The heater ofclaim 2, wherein the power electronics include driver electronics for the resonant circuit.

4: The heater ofclaim 1, wherein the susceptor is at least substantially smooth to mitigate a pressure drop caused by the susceptor.

5: The heater ofclaim 1, wherein the susceptor is provided in the form of a mesh.

6: The heater ofclaim 1, wherein the cylindrical tube is a first cylindrical tube and the susceptor is a first susceptor, and which includes a second cylindrical tube and a second susceptor located within the second cylindrical tube, and

wherein inductive coil extends around the first and second cylindrical tubes.

7: The heater ofclaim 6, wherein the second cylindrical tube has a same inner diameter as the first cylindrical tube.

8: The heater ofclaim 6, wherein the first and second cylindrical tubes are connected by a U-shaped connector.

9: The heater ofclaim 6, wherein the first and second cylindrical tubes are first and second tube portions folded 180 degrees from a single tube.

10: The heater ofclaim 6, further comprising:

a downstream temperature sensor located so as to sense a temperature of fluid heated by the first and second susceptors; and

an upstream temperature sensor located so as to sense a temperature of the fluid prior to being heated,

wherein the downstream and upstream temperature sensors are configured to output to a control unit controlling the power electronics.

11: The heater ofclaim 1, further comprising:

a downstream temperature sensor located so as to sense a temperature of fluid heated by the susceptor;

an upstream temperature sensor located so as to sense a temperature of the fluid prior to being heated,

wherein the downstream and upstream temperature sensors are configured to output to a control unit controlling the power electronics.

12: A dialysis system comprising:

a disposable set including

a tube, and

a susceptor located within the cylindrical tube;

a machine enclosure including an opening sized to accept the cylindrical tube;

an inductive coil located within the machine enclosure and extending around the cylindrical tube when the cylindrical tube is inserted into the opening; and

power electronics located within the machine enclosure, the power electronics in electrical communication with the inductive coil and configured to supply an electrical current to the inductive coil, causing the susceptor to heat.

13: The system ofclaim 12, wherein the cylindrical tube is a first cylindrical tube and the susceptor is a first susceptor, and which includes a second cylindrical tube and a second susceptor located within the second cylindrical tube, and

wherein inductive coil extends around the first and cylindrical tubes when inserted into the opening.

14: The system ofclaim 13, wherein the first and second cylindrical tubes are connected by a U-shaped connector.

15: The system ofclaim 13, wherein the first and second cylindrical tubes are first and second tube portions folded 180 degrees from a single tube.

16: The system ofclaim 13, further comprising:

(i) a downstream temperature sensor located within the machine enclosure so as to sense a temperature of fluid heated by the first and second susceptors when the disposable set is mounted to the machine enclosure; and

(ii) an upstream temperature sensor located within the machine enclosure so as to sense a temperature of the fluid prior to being heated when the disposable set is mounted to the machine enclosure.

17: The system ofclaim 16, further comprising a control unit electrically connected to the downstream and upstream temperature sensors, the control unit configured to control the power electronics.

18: The system ofclaim 12, further comprising:

(i) a downstream temperature sensor located within the machine enclosure so as to sense a temperature of fluid heated by the susceptor when the disposable set is mounted to the machine enclosure; and

(ii) an upstream temperature sensor located within the machine enclosure so as to sense a temperature of the fluid prior to being heated when the disposable set is mounted to the machine enclosure.

19: The system ofclaim 12, wherein the machine enclosure includes a pump actuator, and wherein the disposable set includes a pumping portion for operation with the pump actuator.

20: The system ofclaim 19, wherein the pumping portion includes a cylindrical tube which is the same as or is in fluid communication with the cylindrical tube housing the susceptor.

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