Patent Description:
Regarding renal failure therapy machines, due to various causes, a person's renal system can fail. Toxic end products of nitrogen metabolism (urea, creatinine, uric acid, and others) can accumulate in blood and tissue.

Kidney failure and reduced kidney function have been treated with dialysis. Dialysis treatment for replacement of kidney functions is critical to many people because the treatment is life saving.

HF is accomplished by adding substitution or replacement fluid to the extracorporeal circuit during treatment (typically ten to ninety liters of such fluid). The substitution fluid and the fluid accumulated by the patient in between treatments is ultrafiltered over the course of the HF treatment, providing a convective transport mechanism that is particularly beneficial in removing middle and large molecules (in hemodialysis there is a small amount of waste removed along with the fluid gained between dialysis sessions, however, the solute drag from the removal of that ultrafiltrate is not enough to provide convective clearance).

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

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

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

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

APD machines pump used or spent dialysate from the peritoneal cavity, though the catheter, and to the drain. As with the manual process, several drain, fill and dwell cycles occur during dialysis. A "last fill" occurs at the end of APD and remains in the peritoneal cavity of the patient until the next treatment.

Any of the above modalities performed by a machine may employ pneumatic pumping. Pneumatic pumping typically involves the application of positive and/or negative air pressure to a pumping membrane or diaphragm. Positive pressure may be provided via a compressor feeding a positive pressure tank or accumulator. Negative pressure may be provided via a vacuum pump feeding a negative pressure tank or accumulator. Attempts may be made to remove water from the positive pressure prior to the air being fed to the positive pressure tank accumulator. Water present in positive pressure air can lead to corrosion within the solenoid valves and elsewhere.

The components described above may generate heat or may operate more effectively in a non-heated environment. An improved coordination of such components is needed accordingly.

Additionally, the positive pressure accumulator is effective only until its pressure reaches that needed to drive a certain application. For example, a pressure regulator may be present between the positive pressure accumulator and the application, e.g., a fluid valve. If the regulator is set to deliver <NUM> psig to close the valve, for example, then the accumulator cannot deliver the pressure necessary to close the valve once its pressure falls below <NUM> psig. There may be situations in which it is desirable to have the positive and negative accumulators deliver positive and negative pressure, respectively, for as long as possible. An additional need exists accordingly to extend the useful life of the pneumatic pressure accumulators.

<CIT> discloses a system for peritoneal dialysis that comprises a pump chamber having generally vertically spaced upper and lower regions and a diaphragm to which fluid pressure is applied to operate the pump chamber. The system is designed to direct liquid to the patient's peritoneal cavity only from the lower region of the pump chamber. In this way, air is collected in the upper region of the vertically oriented pump chamber, while isolating the patient's peritoneal cavity from air in the pump chamber.

<CIT> discloses a medical treatment system, such as peritoneal dialysis system, that includes a control system that can adjust the volume of fluid infused into the peritoneal cavity to prevent the intraperitoneal fluid volume from exceeding a pre-determined amount. The control system can adjust by adding one or more therapy cycles, allowing for fill volumes during each cycle to be reduced. The control system may continue to allow the fluid to drain from the peritoneal cavity as completely as possible before starting the next therapy cycle. The control system may also adjust the dwell time of fluid within the peritoneal cavity during therapy cycles in order to complete a therapy within a scheduled time period.

According to the present invention, there is provided a medical fluid delivery machine according to claim <NUM>.

The examples described herein disclose pump box devices, systems and methods therefore applicable, for example, to fluid delivery for: plasmapherisis, hemodialysis ("HD"), hemofiltration ("HF") hemodiafiltration ("HDF"), and continuous renal replacement therapy ("CRRT") treatments. The pump box devices, and systems and methods therefore described herein are also applicable to peritoneal dialysis ("PD") and to intravenous drug delivery. These modalities may be referred to collectively or generally individually as medical fluid delivery.

Moreover, each of the devices, systems and methods described herein may be used with clinical or home-based machines. For example, the systems may be employed in in-center HD, HF or HDF machines, which run throughout the day. Alternatively, the systems may be used with home HD, HF or HDF machines, which are operated at the patient's convenience. One such home system is described in <CIT>, assigned to the assignee of the present application. Another such home system is described in <CIT>.

In an embodiment, the medical fluid delivery machine includes a medical fluid delivery chassis. The medical fluid delivery chassis houses components needed to deliver medical fluid, such as one or more pump, plural valves, a heater if needed, online medical fluid generation equipment if needed and desired, plural sensors, such as any one, or more, or all of pressure sensors, conductivity sensors, temperature sensors, air detectors, blood leak detectors, and the like, a user interface, and a control unit, which may employ one or more processor and memory to control the above-described equipment.

Various components, such as the fluid pumps and valves, may be actuated pneumatically. In such a case, it is contemplated to provide a pneumatic pump box, which houses equipment needed to generate and store positive and/or negative pressure air. "Air" as used herein means air as it exists naturally, which is made up of individual gases such as nitrogen, oxygen, argon, and carbon dioxide. "Air" may also include a desired modified atmosphere, such as a larger percentage of, or a pure gas, such nitrogen or carbon dioxide. The term "pneumatic" also refers to naturally occurring air and/or any type of modified atmosphere.

The pneumatic pump box may house components, such as a vacuum pump for supplying negative air pressure, a compressor for supplying positive air pressure, a dryer for removing water from the positive pressure air outputted from the compressor prior to storage in the accumulator, and positive and negative accumulators for storing positive and negative air pressure, respectvely. The pneumatic pump box may be attached removeably to the medical fluid delivery chassis. If the medical fluid delivery machine is to be operated while the patient is sleeping, for example, or if the patient desires a quiet environment for whatever reason, it may be desirable for the patient to remove the pneumatic pump box and store it in a closet or other remote location to dampen its noise. The removable pneumatic pump box is connected pneumatically to the medical fluid delivery chassis via one or more positive and negative pressure lines and may receive electrical power via its own electrical cord or via an electrical power feed from the chassis.

The pneumatic pump box's vacuum pump is typically the hottest point in the box during operation. The dryer in an embodiment cools air from the compressor to condense water from the compressed air, so that the water may be removed before being delivered into the positive pressure accumulator. Removing water from the compressed air is important because water in the compressed air volume may cause system failure due to corrosion. The pneumatic box of the present disclosure accordingly places the vacuum pump at the top of the pneumatic pump box. Here, heat rises from the vacuum pump to the top of the box, such that its impact on the other components in the box is minimized. It is further contemplated to place a small, inexpensive fan directly in the top of the box directly above the dryer, which is oriented to pull the heated air out of the box. Intake vents for the fan may be provided in the pump box, e.g., just below the vacuum pump.

With the vacuum pump placed at the top of the pump box, the goals for locating the remainder of the equipment are two-fold, namely, (i) to locate the dryer as far away from the vacuum pump as possible to prevent heat generated from the vacuum pump from heating the dryer, and (ii) to reduce and simplify the routing of tubing between the pneumatic pump box as much as possible. To this end, either the compressor or the dryer may be located at the bottom of the box. Locating the compressor at the bottom of the box, the dryer above the compressor and the accumulators above the dryer optimizes the routing of tubing and other air connections, which run from the compressor to the dryer, and from the dryer to the positive pressure accumulator. On the other hand, locating the dryer at the bottom of the box, the compressor above the dryer, and the accumulators above the compressor, spaces the dryer (e.g., chilling device) as far away as possible from the heat-producing vacuum pump.

In an embodiment, the pneumatic pump box includes two accumulators, namely, a positive pressure accumulator and a negative pressure accumulator. It is possible that the pneumatic pump and valve control may use different pressure levels at different locations within the medical fluid delivery machine. For example, a pneumatic pump may include a pump chamber associated with its own inlet and outlet valve chambers, wherein the pressure applied to the valve chambers is greater than the pressure applied to the pump chamber, so that operation of the pump chamber does not affect a desired valve state. In another example, it may be desirable to apply less pressure to a blood pump operation than to a dialysis fluid operation, to better avoid damaging blood cells or other blood components. In any case, multiple accumulators may be provided to store multiple positive and/or negative pressures. In one preferred embodiment, however, a single positive pressure accumulator and a single negative pressure accumulator are provided to feed multiple pneumatic regulators that set the different desired positive and/or negative pneumatic operating pressures.

The pneumatic regulators may include static regulators that set a desired positive or negative pneumatic pressure, for example, to feed multiple on/off or binary applications. The pneumatic regulators may alternatively or additionally include a variable diameter orifice, e.g., as a variable valve or vari-valve. Components, such as the pneumatic regulators, binary pneumatic valves and the vari-valves are placed in an embodiment on a manifold that is located inside the medical fluid delivery chassis, so that single positive and negative pressure lines from the pneumatic pump box to the chassis can feed each of the components of the manifold.

To improve the efficiency of the accumulators, it is contemplated to sealingly secure an elastic accumulator bladder inside of an outer, rigid positive pressure accumulator housing, which limits the size to which the bladder can expand, and also defines the shape of the bladder when expanded to fill the volume of the accumulator housing fully. The bladder is formed to require a certain positive pressure for inflation, namely, the bladder inflation pressure. The rigid outer chamber is vented in an embodiment, so that air between the bladder and rigid outer chamber can be displaced to atmosphere when the bladder is inflated. When positive pressure air is withdrawn initially from the accumulator bladder, no shape change occurs, and the accumulator assembly acts as a conventional ridged accumulator until the pressure in the bladder falls to the bladder inflation pressure. When the positive pressure starts to fall below the bladder inflation pressure, the accumulator bladder contracts and continues to deliver positive pressure air volume at the bladder inflation pressure until the accumulator bladder is fully contracted. During contraction, atmospheric air is drawn into the rigid outer container outside of the bladder via the vent. The overall volume of air delivered is greater than that possible with a rigid accumulator alone due to the force applied by the bladder elastomer to the internal bladder air volume.

Typically, the accumulator is charged via a compressor to a set pressure, which is above a desired operating pressure. The desired operating pressure is achieved by using a regulator to set an accurate downstream pneumatic pressure. It is contemplated to construct the bladder to make the bladder inflation pressure just slightly above the desired operating pressure. In this manner, most all of the pressure delta between the set charging pressure and the desired operation pressure is consumed prior to the contraction of the bladder.

The fluid valves are closed under positive pressure and opened by venting the positive pressure to atmosphere. For example, a first electrically operated solenoid valve may be provided to allow or not allow positive pressure to flow or not flow to the fluid valve. A second electrically operated solenoid valve is provided to allow or not allow the positive pressure to vent to atmosphere. To close the fluid valve, the first electrically operated solenoid valve is opened, while the second electrically operated solenoid valve is closed, which allows the fluid valve to see positive air pressure, which is not vented. To open the fluid valve, the first electrically operated solenoid valve is closed, while the second electrically operated solenoid valve is opened, which shuts off positive pressure to the fluid valve and vents the existing positive pressure at the fluid valve to atmosphere, enabling the fluid valve to open. The fluid valve may open due to the force of fluid pressure on the fluid side of a valve diaphragm and/or the valve diaphragm may be preformed or predomed and be placed or positioned so as to be biased fluid open when not under positive pressure. It should be appreciated then that in one embodiment, while the pump chamber requires positive and negative pneumatic pressure, the corresponding valve chambers only require positive pneumatic pressure. The life of the fluid pump including inlet and outlet valves may therefore be extended by extending the life of the positive pressure via the accumulator bladder of the present disclosure without a corresponding extension of the life of the negative pressure source.

Nevertheless, it is also contemplated to increase the life of the negative pressure source. Here, a reverse accumulator structure is applied to the negative pressure accumulator. In one example, an elastic bladder is preformed to have the same shape as for the positive pressure accumulator. The difference is that the vacuum is applied to the vent port of the positive chamber to draw a vacuum on the air between the bladder and the rigid outer chamber of the negative pressure accumulator. The vent port for the negative pressure accumulator is the port leading to the inside of the bladder (which is the supply port for the positive accumulator). The negative pressure bladder is thickened as necessary to fully inflate under a more negative pressure than the desired regulated negative pressure, so that the bladder can provide the negative pressure to drive the negative regulator until the bladder is fully contracted. In various embodiments, (i) the bladder and the ridged outer housing accumulator are configured so that a full vacuum can be drawn before the negative pressure bladder expands to block or fully block the vacuum port provided by the housing, and/or (ii) the vacuum port can be angled on the inside of the rigid housing so that it is difficult for the bladder to block. Thus unlike the positive pressure bladder, which does not contract until positive pressure inside the bladder falls to the bladder inflation pressure, the negative pressure accumulator begins to contract after the negative pressure in the vacuum line starts to become less negative than the required negative bladder inflation pressure (not enough negative pressure to keep the bladder fully expanded. However, the negative pressure remains at the negative pressure inflation pressure until the bladder is fully contracted, leaving the rigid outer chamber virtually fully charged with negative pressure to drive the negative regulator.

As discussed herein, in both the positive and negative pressure bladder instances, the outer, rigid accumulator housing is vented to atmosphere so that the bladder can inflate and contract freely under positive or negative pressure.

It may be desirable that to still be able to deliver positive and/or negative air pressure when power to the medical fluid delivery machine is lost. For example, it may be desirable to push blood back to the patient to allow the patient to disconnect from a dialysis machine. Here, the dialysis machine may provide battery power to power the pneumatic valves, enabling pneumatic pressure to be applied to the fluid valves and pump chambers. The bladders increase the volume of positive and negative pressure air that can be extracted from the accumulators to maintain the desired working pressure for a longer period, allowing more blood to be pushed back to the patient. Alternatively or additionally, the additional working pressure may be used to lower the leak tightness requirements of the on-off binary and vari-valves, making the overall machine more robust.

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

It is another advantage of the present disclosure to provide an improved pneumatic pump box for a medical fluid delivery device.

It is a further advantage of the present disclosure to provide a pneumatic pump box for a medical fluid delivery device that is thermally efficient.

It is still another advantage of the present disclosure to provide a pneumatic pump box for a medical fluid delivery device having efficient tubing routing.

It is still a further advantage of the present disclosure to provide a pneumatic pressure accumulator having extended usability.

It is yet another advantage of the present disclosure to provide a pneumatic pumping system that can operate efficiently upon loss of power.

It is yet a further advantage of the present disclosure to provide a pneumatic pumping system that can preserve positive and negative pneumatic pressure.

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

The examples described herein are applicable to any medical fluid delivery system that delivers a medical fluid, such as blood, dialysis fluid, substitution fluid or and intravenous drug ("IV"). The examples are particularly well suited for kidney failure therapies, such as all forms of hemodialysis ("HD"), hemofiltration ("HF"), hemodiafiltration ("HDF"), continuous renal replacement therapies ("CRRT") and peritoneal dialysis ("PD"), referred to herein collectively or generally individually as renal failure therapy. Moreover, the machines and any of the pneumatic pumping systems and methods described herein may be used in clinical or home settings. For example, a machine including pneumatic pumping structure may be employed in an in-center HD machine, which runs virtually continuously throughout the day. Alternatively, the pneumatic pumping structure may be used in a home HD machine, which can for example be run at night while the patient is sleeping. Moreover, each of the renal failure therapy examples described herein may employ a diffusion membrane or filter, such as a dialyzer, e.g., for HD or HDF, or a hemofilter, e.g., for HF.

Referring now to <FIG>, an example of an HD flow schematic for a medical fluid delivery system <NUM> employing a pneumatic pump box of the present disclosure is illustrated. Because the HD system of <FIG> is relatively complicated, <FIG> and its discussion also provide support for any of the renal failure therapy modalities discussed above and for an IV machine. Generally, system <NUM> is shown having a very simplified version of a dialysis fluid or process fluid delivery circuit. The blood circuit is also simplified but not to the degree that the dialysis fluid circuit is simplified. It should be appreciated that the circuits have been simplified to make the description of the present disclosure easier, and that the systems if implemented would have additional structure and functionality, such as is found in the publications mentioned above.

System <NUM> of <FIG> includes a blood circuit <NUM>. Blood circuit <NUM> pulls blood from and returns blood to a patient <NUM>. Blood is pulled from patient <NUM> via an arterial line <NUM>, and is returned to the patient via a venous line <NUM>. Arterial line <NUM> includes an arterial line connector 14a that connects to an arterial needle 14b, which is in blood draw communication with patient <NUM>. Venous line <NUM> includes a venous line connector 16a that connects to a venous needle 16b, which is in blood return flow communication with the patient. Arterial and venous lines <NUM> and <NUM> also include line clamps 18a and 18v, which can be spring-loaded, fail-safe mechanical pinch clamps. Line clamps 18a and 18v are closed automatically in an emergency situation in one procedure.

Arterial and venous lines <NUM> and <NUM> also include air or bubble detectors 22a and 22v, respectively, which can be ultrasonic air detectors. Air or bubble detectors 22a and 22v look for air in the arterial and venous lines <NUM> and <NUM>, respectively. If air is detected by one of air detectors 22a and 22v, system <NUM> closes line clamps 18a and 18v, pauses the blood and dialysis fluid pumps, and provides instructions to the patient to clear the air so that treatment can resume.

A blood pump <NUM> is located in arterial line <NUM> in the illustrated arrangement and includes a first blood pump pod 30a and a second blood pump pod 30b. Blood pump pod 30a operates with an inlet valve 32i and an outlet valve 32o. Blood pump pod 30b operates with an inlet valve 34i and an outlet valve 34o. In an embodiment, blood pump pods 30a and 30b are each blood receptacles that include a hard outer shell, e.g., spherical, with a flexible diaphragm located within the shell, forming a diaphragm pump. One side of each diaphragm receives blood, while the other side of each diaphragm is operated by negative and positive air pressure. Blood pump <NUM> is alternatively a peristaltic pump operating with the arterial line <NUM> tube.

A heparin vial <NUM> and heparin pump <NUM> are located between blood pump <NUM> and blood filter <NUM> (e.g., dialyzer) in the illustrated arrangement. Heparin pump <NUM> may be a pneumatic pump or a syringe pump (e.g., stepper motor driven syringe pump). Supplying heparin upstream of blood filter <NUM> helps to prevent clotting of the filter's membranes.

A control unit <NUM> includes one or more processor and memory. Control unit <NUM> receives air detection signals from air detectors 22a and 22v (and other sensors of system <NUM>, such as temperature sensors, blood leak detectors, conductivity sensors, pressure sensors, and access disconnection transducers <NUM>, <NUM>), and controls components such as line clamps 18a and 18v, blood pump <NUM>, heparin pump <NUM>, and the dialysis fluid pumps. Blood exiting blood filter <NUM> via venous line <NUM> flows through an airtrap <NUM>. Airtrap <NUM> removes air from the blood before the dialyzed blood is returned to patient <NUM> via venous line <NUM>.

With the hemodialysis version of system <NUM> of <FIG>, dialysis fluid or dialysate is pumped along the outside of the membranes of blood filter <NUM>, while blood is pumped through the insides of the blood filter membranes. Dialysis fluid or dialysate is prepared beginning with the purification of water via a water purification unit <NUM>. One suitable water purification unit is set forth in <CIT>. In one system, water purification unit includes filters and other structures to purify tap water (e.g., remove pathogens and ions such as chlorine), so that the water is in one implementation below <NUM> endotoxin units/ml ("EU/ml") and below <NUM> colony forming units/ml ("CFU/ml"). Water purification unit <NUM> may be provided in a housing separate from the housing of the hemodialysis machine, which includes blood circuit <NUM> and a dialysis fluid circuit <NUM>.

Dialysis fluid circuit <NUM> is again highly simplified in <FIG> to ease illustration. Dialysis fluid circuit <NUM> in actuality may include all of the relevant structure and functionality set forth in the publications mentioned above. Certain features of dialysis fluid circuit <NUM> are illustrated in <FIG>. In the illustrated system, dialysis fluid circuit <NUM> includes a to-blood filter dialysis fluid pump <NUM>. Pump <NUM> is in one system configured the same as blood pump <NUM>. Pump <NUM>, like pump <NUM>, includes a pair of pump pods, which again may be spherically configured. The two pump pods, like with blood pump <NUM>, are operated alternatingly so that one pump pod is filling with HD dialysis fluid, while the other pump pod is expelling HD dialysis fluid.

Pump <NUM> is a to-blood filter dialysis fluid pump. There is another dual pod pump chamber <NUM> operating with inlet valve 98i and outlet valve 98o located in drain line <NUM> to push used dialysis fluid to drain. There is a third pod pump (not illustrated) for pumping pump purified water through a bicarbonate cartridge <NUM>. There is a fourth pod pump (not illustrated) used to pump acid from acid container <NUM> into mixing line <NUM>. The third and fourth pumps, the concentrate pumps, may be single pod pumps because continuous pumping is not as important in mixing line <NUM> because there is a buffering dialysis fluid tank (not illustrated) between mixing line <NUM> and to-blood filter dialysis fluid pump <NUM> in one system.

A fifth pod pump (not illustrated) provided in drain line <NUM> is used to remove a known amount of ultrafiltration ("UF") when an HD therapy is provided. System <NUM> keeps track of the UF pump to control and know how much ultrafiltrate has been removed from the patient. System <NUM> ensures that the necessary amount of ultrafiltrate is removed from the patient by the end of treatment.

Each of the above-described pumps may alternatively be a peristaltic pump operating with a tube. If so, the system valves may still be actuated pneumatically according to the features of the present disclosure.

In one system, purified water from water purification unit <NUM> is pumped along mixing line <NUM> though bicarbonate cartridge <NUM>. Acid from container <NUM> is pumped along mixing line <NUM> into the bicarbonated water flowing from bicarbonate cartridge <NUM> to form an electrolytically and physiologically compatible dialysis fluid solution. The pumps and temperature-compensated conductivity sensors used to mix the purified water properly with the bicarbonate and acid are not illustrated but are disclosed in detail in the publications mentioned above.

<FIG> also illustrates that dialysis fluid is pumped along a fresh dialysis fluid line <NUM>, through a heater <NUM> and an ultrafilter <NUM>, before reaching blood filter <NUM>, after which used dialysis fluid is pumped to drain via drain line <NUM>. Heater <NUM> heats the dialysis fluid to body temperature or about <NUM>° C. Ultrafilter <NUM> further cleans and purifies the dialysis fluid before reaching blood filter <NUM>, filtering bugs or contaminants introduced for example via bicarbonate cartridge <NUM> or acid container <NUM> from the dialysis fluid.

Dialysis fluid circuit <NUM> also includes a sample port <NUM> in the illustrated system. Dialysis fluid circuit <NUM> will further include a blood leak detector (not illustrated but used to detect if a blood filter <NUM> fiber is torn) and other components that are not illustrated, such as balance chambers, plural dialysis fluid valves, and a dialysis fluid holding tank, all illustrated and described in detail in the publications mentioned above.

In the illustration, hemodialysis system <NUM> is an online, pass-through system that pumps dialysis fluid through blood filter one time and then pumps the used dialysis fluid to drain. Both blood circuit <NUM> and dialysis fluid circuit <NUM> may be hot water disinfected after each treatment, such that blood circuit <NUM> and dialysis fluid circuit <NUM> may be reused. In one implementation, blood circuit <NUM> including blood filter <NUM> is hot water disinfected and reused daily for about one month, while dialysis fluid circuit <NUM> is hot water disinfected and reused for about six months.

In alternative systems, for CRRT for example, multiple bags of sterilized dialysis fluid or infusate are ganged together and used one after another. In such a case, the emptied supply bags can serve as drain or spent fluid bags.

The machine <NUM> of system <NUM> includes an enclosure as indicated by the dotted line of <FIG>. The enclosure of machine <NUM> varies depending upon the type of treatment, whether the treatment is in-center or a home treatment, and whether the dialysis fluid/infusate supply is a batch-type (e.g., bagged) or on-line.

<FIG> illustrates that machine <NUM> of system <NUM> of <FIG> may operate with a blood set <NUM>. Blood set <NUM> includes arterial line <NUM>, venous line <NUM>, heparin vial <NUM>, heparin pump <NUM>/blood pump <NUM> and blood filter <NUM> (e.g., dialyzer). An airtrap <NUM> may be located in venous line <NUM> to remove air from the blood before being returned to patient <NUM>.

In <FIG> and <FIG>, any of pumps <NUM>, <NUM> (30a and 30b), <NUM>, <NUM> (and other pumps not illustrated) and any of the valves, such as valves 32i, 32o, 34i, 34o, 68i, 68o, 98i and 98o may be pneumatically actuated. In an embodiment, each of the pumps and valves has a fluid side and an air side, separated by a flexible membrane. Negative pneumatic pressure may be applied to the air side of the membrane to draw fluid into a pump chamber or to open a valve (or pump or valve could be opened by venting positive closing pressure to atmosphere and allowing fluid pressure to open). Positive pneumatic pressure is applied to the air side of the membrane to expel fluid from a pump chamber or to close a valve.

Referring now to <FIG>, an embodiment of a medical fluid delivery machine <NUM>, such as an HD machine, is illustrated. Medical fluid delivery machine <NUM> in the illustrated embodiment includes a medical fluid delivery chassis <NUM> connected to a pneumatic pump box <NUM>. In an embodiment, pneumatic pump box <NUM> is connected removeably to medical fluid delivery chassis <NUM>, so that the pump box can be moved away from the patient (e.g., placed in a closet) to reduce noise in the treatment area near the vicinity of the patient. At least one positive pneumatic line and at least one negative pneumatic line (not illustrated) run from pneumatic pump box <NUM> to medical fluid delivery chassis <NUM> to drive pumps <NUM>, <NUM> (30a and 30b), <NUM>, <NUM> (and other pumps not illustrated) and any of the valves, such as valves 32i, 32o, 34i, 34o, 68i, 68o, 98i and 98o, which are located within or are mounted onto medical fluid delivery chassis <NUM>.

In an embodiment, pneumatic components, such as, pneumatic regulators, electrically actuated binary solenoid valves, and electrically actuated variable pneumatic (vari-valves) are located within medical fluid delivery chassis <NUM>. The number of pneumatic lines running from pneumatic pump box <NUM> to medical fluid delivery chassis <NUM> can therefore be minimized, perhaps to a single positive pressure pneumatic line and a single negative pressure pneumatic line.

<FIG> illustrate alternative pneumatic pump boxes 150a and 150b (collectively pump box <NUM>) in more detail. Pump boxes 150a and 150b have been simplified to highlight their primary components and may contain other structure, not illustrated, such as electrical wiring and circuitry, tubing, connectors, etc. Pneumatic pump boxes 150a and 150b of <FIG>, respectively, recognize that the vacuum pump <NUM> produces heat and accordingly forms the hottest point in the pump box during operation. Vacuum pump <NUM> is accordingly mounted at the top within both pneumatic pump boxes 150a and 150b, so that heat may rise up and away from the other pump box components.

Pneumatic pump box 150a also reduces and simplifies the routing of tubing within the pneumatic pump box as much as possible. To do so, pneumatic pump box 150a locates a compressor <NUM> at the bottom of pneumatic pump box 150a. Compressor <NUM> feeds compressed air into a dryer <NUM> via a short pneumatic line <NUM>. Dryer <NUM> in an embodiment cools the compressed air from compressor <NUM>, condensing water out of compressed air. Removing water from the air prior to use is important because water in the compressed air volume can cause system failure due to corrosion. Because dryer <NUM> operates in an embodiment via cooling, it is prudent to locate dryer <NUM> away from the heat-producing vacuum pump <NUM>. In pump box 150a, dryer <NUM> is located beneath vacuum pump <NUM>, avoiding its rising heat, and is separated from vacuum pump <NUM> via accumulators <NUM> and <NUM>. Tubing routing is likewise simplified and reduced via short pneumatic line <NUM> between dryer <NUM> and positive pressure accumulator <NUM> and short tubing line <NUM> between vacuum pump <NUM> and negative pressure accumulator <NUM>.

Positive pressure accumulator <NUM> includes an output port <NUM> for connecting to a positive pressure pneumatic line (not illustrated), supplying positive pressure to medical fluid delivery chassis <NUM>. Negative pressure accumulator <NUM> includes an output port <NUM> for connecting to a negative pressure pneumatic line (not illustrated), supplying negative pressure to medical fluid delivery chassis <NUM>.

Alternative pneumatic pump box 150b flips the placement of compressor <NUM> and dryer <NUM> relative to pneumatic pump box 150a, so that compressor <NUM> instead lies above dryer <NUM>. This configuration moves cooling dryer <NUM> further away from heat-producing vacuum pump <NUM> and also below heat rising from the compressor, which is advantageous, but requires a longer pneumatic line <NUM> between dryer <NUM> and positive pressure accumulator <NUM>. In any case, component layouts of both pneumatic pump box 150a and 150b are made with efficiency and simplicity in mind.

Either one or both of pneumatic pump boxes 150a and 150b may provide an electrically operated fan <NUM> at the top of the box, which is oriented to pull heated air from vacuum pump <NUM> out of the box. To aid in the circulation of cooler ambient air about vacuum pump <NUM>, inlet vents <NUM> may be provided and located as illustrated just beneath the location of vacuum pump <NUM>. As illustrated by the convection arrows in <FIG>, relatively cool air is pulled in through vents <NUM> and about vacuum pump <NUM> via fan <NUM>, which also exhausts the heated out of pneumatic pump box 150a or 150b.

Either one or both of pneumatic pump boxes 150a and 150b may also provide sound insulation <NUM> on one or more or all of the inner walls of the pump boxes. Sound insulation <NUM>, such as foam or rockwool, lining the inner walls of pump boxes 150a and 150b, helps to muffle noise produced via pneumatic components <NUM>, <NUM> and <NUM>. The insulation may eliminate the need to remove pump box <NUM> from medical fluid delivery chassis <NUM>. Indeed, it is contemplated to integrate pump box <NUM>, including any of the disclosure and alternatives described herein, into medical fluid delivery chassis <NUM> of machine <NUM>.

Referring now to <FIG>, embodiments of pressure accumulators <NUM>, <NUM> are illustrated. As illustrated in <FIG>, positive pressure accumulator <NUM> includes a rigid outer housing <NUM>, which can be made of a plastic material, such as polyvinylchloride ("PVC"), polycarbonate ("PC"), polypropylene ("PP"), polyethylene ("PE"), for example. Rigid outer housing <NUM> in the illustrated embodiment has an inner surface that attempts two eliminate sharp corners and instead includes relatively large radius bends <NUM> that enable a bladder to conform readily to a shape of the inner surface, to use all or substantially all of the inner volume defined by the inner surface. In an embodiment, the inner volume defined by rigid housing may be from about <NUM> milliliters to a liter or more, e.g., <NUM> milliliters.

Rigid outer housing <NUM> in the illustrated embodiment includes or provides a vent port <NUM>. Vent port <NUM> is in one embodiment molded with the rest of rigid housing <NUM>. Vent port <NUM> allows a bladder <NUM> described below to push air out of housing <NUM> when bladder <NUM> expands and for air to enter housing <NUM> when bladder <NUM> contracts. Housing <NUM> nevertheless provides the ridged enclosure needed to contain the bladder <NUM>. Port <NUM> helps the bladder to expand fully and contract readily.

An open end of rigid outer housing <NUM> in the illustrated embodiment accepts a bladder assembly <NUM> illustrated in <FIG>. Bladder assembly <NUM> includes an expandable bladder <NUM>. Expandable bladder <NUM> is made of a highly elastic material, such as latex. <FIG> illustrates that the open end <NUM> of bladder <NUM> is stretched and sealed over a bladder connection end <NUM> of a connector <NUM>. Connector <NUM> also provides output ports <NUM>, <NUM> described above in connection with <FIG>, respectively, for connecting to positive or negative pressure lines (not illustrated), supplying positive or negative pressure to medical fluid delivery chassis <NUM>. Output ports <NUM>, <NUM> may be barbed as illustrated for sealed connection with the pneumatic lines, or have other suitable airtight sealing connections. Connector <NUM> may be made from any of the rigid plastics described above for rigid outer housing <NUM>, including nylon additionally. Connector <NUM> may also be injection molded to provide closer tolerances than can be achieved via blow molding, which may be used to form rigid housing <NUM>.

A gasket <NUM>, such as an o-ring gasket further compresses expandable bladder <NUM> onto bladder connection end <NUM> of a connector <NUM>. Bladder connection end <NUM> in an embodiment provides an annular indent to seat gasket <NUM> onto bladder <NUM> and bladder connection end. Gasket <NUM> is also sized to compresses within a neck <NUM> of rigid outer housing <NUM> when bladder assembly <NUM> is inserted into outer housing <NUM>. A flange <NUM> of connector <NUM> seats against the front of neck <NUM> when bladder assembly <NUM> is fully inserted into outer housing <NUM>. Gasket <NUM> may be made of silicon or other compressible rubber or plastic.

In an alternative embodiment, both output ports <NUM>, <NUM> and bladder connection end <NUM> of connector <NUM> are barbed. Housing <NUM> and its neck <NUM> may be made of a softer material than barbed connection end <NUM> of connector <NUM>, such that the barbs can dig into and seal to neck <NUM> of housing <NUM>.

In a further alternative embodiment, output ports <NUM>, <NUM> of connector <NUM> may be smooth and seal to a pneumatic tube via one or more o-ring gasket, e.g., fitted into groove formed in output ports <NUM>, <NUM>. Here, bladder connection end <NUM> can be smooth as illustrated or barbed as described alternatively above.

Assume for purposes of illustration that a positive pressure regulator, such as a static regulator or a vari-valve, sets the operating pressure at the fluid pump chamber or fluid valve chamber to <NUM> psig. It is contemplated then to construct bladder <NUM> (e.g., via setting its wall thickness), so that it requires at least slightly above <NUM> psig, such as <NUM>. 5psig, to inflate the bladder. The pressure needed to inflate the bladder also needs to be below the output pressure of compressor <NUM> and dryer <NUM>. By doing so, bladder <NUM> provides sufficient operating pressure to the regulator when the bladder contracts from its expanded shape illustrated in <FIG> to its resting shape illustrated in <FIG>. Without bladder <NUM>, once the pressure in rigid outer housing <NUM> falls to <NUM> psig in the example, accumulator <NUM> can no longer power a fluid valve or pump. But with bladder <NUM>, once the pressure in rigid outer housing <NUM> falls to the bladder inflation pressure (e.g., slightly above <NUM> psig or <NUM> psig in the example), bladder <NUM> supplies the bladder inflation pressure to the regulator, e.g., <NUM> psig, until bladder <NUM> reaches its resting shape.

<FIG> illustrates a graph of the pressure provided by accumulator <NUM> over time, showing the pressure (i) start at the initial positive pressure provided by compressor <NUM> to accumulator <NUM>, (ii) fall either linearly or according to a curve to the bladder inflation pressure, (iii) remain at the inflation pressure until bladder <NUM> reaches its non-expanded resting shape, and (iv) fall to the regulated output pressure.

The additional amount or volume may be used, for example, to drive a pump or valve chamber when power to compressor <NUM> is no longer available. The additional amount or volume may also be used to lessen the leak-tightness requirements for the pneumatic components, such as the regulators, binary solenoid valves and vari-valves. Lessening such requirements may allow of a cheaper valve to be used and/or lessen the number of fault situations when such pneumatic components are tested before treatment.

<FIG> also illustrate an embodiment of negative pressure accumulator <NUM>. All of the above structure and alternatives described above for positive pressure accumulator <NUM> are the same for negative pressure accumulator <NUM>, except that (i) bladder <NUM>, e.g., made of latex, silicone or other flexible material, is thickened to have a higher inflation pressure and (ii) the roles of vent port <NUM> and connector <NUM> are reversed, so that vent port becomes the vacuum source port and connector <NUM> becomes the air vent. With negative pressure accumulator <NUM>, vacuum pump <NUM> draws a vacuum on port <NUM>, which evacuates the air between bladder <NUM> and rigid outer housing <NUM>, while air is able to enter the inside of bladder <NUM> via connector <NUM> to backfill the bladder.

Negative pressure bladder <NUM> is structured (e.g., via setting its wall thickness), such that it takes a full vacuum amount of negative pressure to inflate the bladder in one embodiment. For example, if it is desired to charge negative pressure accumulator <NUM> to - 15psig, negative pressure bladder <NUM> may be structured such that it takes -15psig to inflate the bladder, assuming vacuum pump <NUM> can provide at least -15psig. In this manner, the space between fully contracted bladder <NUM> and rigid outer housing <NUM> is fully evacuated to a full, desired amount prior to bladder inflating to cover vacuum inlet port <NUM>. In various embodiments, (i) the bladder and the ridged outer housing accumulator are configured so that a full vacuum can be drawn before the negative pressure bladder expands to block or fully block the vacuum port provided by the housing, and/or (ii) the vacuum port can be angled on the inside of the rigid housing so that it is difficult for the bladder to block. When in use, once the negative pressure begins to fall below the negative pressure inflation level, bladder <NUM> begins to contract, supplying the negative inflation pressure until the bladder is contracted fully. When bladder <NUM> is fully contracted, rigid outer housing <NUM> is left with a fully charged vacuum.

<FIG> illustrates a graph of the negative pressure provided by accumulator <NUM> over time, showing the pressure (i) start at the initial negative pressure setpoint provided by vacuum pump <NUM> to accumulator <NUM>, (ii) fall slightly to or just below the negative inflation pressure of bladder <NUM>, (iii) remain at the negative inflation pressure until bladder <NUM> is fully contracted, and (iv) fall either linearly or according to a curve to a negative regulated output pressure. Vent <NUM> allows air to escape the inside of bladder <NUM> so that the bladder may contract fully.

One illustrative pressure setting example for positive pressure accumulator <NUM> versus negative pressure accumulator <NUM> is as follows: (pos) positive pressure chamber pressure +15psig, positive pressure bladder inflation pressure +<NUM>. 5psig, positive pressure regulated output pressure +<NUM>. 0psig, versus (neg) negative pressure chamber pressure -15psig, negative pressure bladder inflation pressure -<NUM> psig, negative pressure regulated output pressure -<NUM>.

Referring now to <FIG>, for use in power loss situations, battery power may be provided with accumulators <NUM> and <NUM> and associated bladders <NUM> to power the electrically operated solenoid and vari-valves, so that negative and positive pressure may be applied to a medical fluid pump <NUM> including a pneumatically actuated pump chamber <NUM> and first and second pneumatically actuated medical fluid valve chambers <NUM> and <NUM> located respectively upstream and downstream of the pneumatically actuated pump chamber <NUM>. Binary solenoid valves 240a to 240f are in one embodiment spring closed and powered open, so that batter power is only needed to open the valves. Vari-valve <NUM> needs power throughout its operation. Static pneumatic regulators <NUM> and <NUM> in one embodiment do not need power. Static pneumatic regulators <NUM> and <NUM> set constant positive and negative pneumatic operating pressures as discussed above.

Viewing additionally the blood set <NUM> of <FIG>, to rinse blood back to the patient towards connectors 14a and 16a through the blood set using dialysis fluid across dialyzer <NUM> to push the blood, battery power is needed to open the solenoids and operate the vari-valves associated with the blood pump (which may be configured like pump <NUM>) and/or a fresh dialysis fluid pump (which may be configured like pump <NUM>). Balance chambers may also be employed, which are bypassed for rinseback in one embodiment. The used dialysis fluid pump may be shut down (inlet and outlet valves closed), so that positive dialysis fluid pressure may be built in the dialyzer for the dialysis fluid flow into the blood set to push blood back towards the patient.

<FIG> illustrates that in one embodiment, pneumatically actuated pump chamber <NUM> includes a housing <NUM>, e.g., a rigid plastic housing, defining a medical fluid side <NUM> (e.g., blood, dialysis fluid, substiution fluid, intravenous drug) and a pneumatic side <NUM>, separated by a flexible membrane or diaphragm <NUM>. Pneumatically actuated first or inlet valve <NUM> includes a housing <NUM>, e.g., a rigid plastic housing, defining a medical fluid side <NUM> and a pneumatic side <NUM>, separated by a flexible membrane or diaphragm <NUM>. Pneumatically actuated second or outlet valve <NUM> includes a housing <NUM>, e.g., a rigid plastic housing, defining a medical fluid side <NUM> and a pneumatic side <NUM>, separated by a flexible membrane or diaphragm <NUM>. Inlet valve <NUM> selectivelty allows medical fluid to flow to pump chamber <NUM> via medical fluid inlet line <NUM>, while outlet valve <NUM> selectivelty allows medical fluid to flow from pump chamber <NUM> via medical fluid outlet line <NUM>.

To draw medical fluid into pump chamber <NUM>, inlet valve <NUM> is opened, outlet valve <NUM> is closed and negative pneumatic pressure is applied to pumping membrane <NUM> to pull the membrane towards vari-valve <NUM>, sucking fluid into pump chamber <NUM> via inlet line <NUM>. To push medical fluid from pump chamber <NUM>, inlet valve <NUM> is closed, outlet valve <NUM> is opened and positive pneumatic pressure is applied to pumping membrane <NUM> to push the membrane away from vari-valve <NUM>, pushing fluid from pump chamber <NUM> via outlet line <NUM>. Vari-valve <NUM> includes a varaible orifice that allows a desired variation of positive and/or negative pneumatic pressure, within ranges set by pneumatic regulators <NUM> and <NUM>, over the course of a stroke of pump chamber <NUM>. Binary valve 240c (e.g., spring closed, energized open) selectivly allows regulated negative pressure to reach vari-valve <NUM>, while binary valve 240d (e.g., spring closed, energized open) selectivly allows regulated positive pressure to reach vari-valve <NUM>.

In the illustrated embodiment, first or inlet valve <NUM> and second or outlet valve <NUM> are closed under positive pressure and opened to atmosphere. To close inlet valve <NUM>, binary valve 240b is opened, while binary valve 240a is closed, allowing regulated positive pressure to close inlet valve <NUM> and to prevent the positive pressure from venting to atmosphere. To open inlet valve <NUM>, binary valve 240b is closed, while binary valve 240a is opened, preventing regulated positive pressure from reaching inlet valve <NUM> and enabling the existing positive pressure at inlet valve <NUM> to vent to atmosphere. Likewise, to close outlet valve <NUM>, binary valve 240e is opened, while binary valve 240f is closed, allowing regulated positive pressure to close outlet valve <NUM> and to prevent the positive pressure from venting to atmosphere. To open outlet valve <NUM>, binary valve 240e is closed, while binary valve 240f is opened, preventing regulated positive pressure from reaching outlet valve <NUM> and enabling the existing positive pressure at outlet valve <NUM> to vent to atmosphere.

Binary valves 240a to 240f and vari-valve <NUM> (as indicated by dashed electrical lines) are operated under the control of control unit <NUM> (also showing dashed electrical lines). Control unit <NUM> runs a computer program that sequences binary valves 240a to 240f as discussed above and controls the orifice size of vari-valve <NUM> to create a desired pumping pressure profile.

Inlet and outlet valves <NUM> and <NUM> may open when vented to atmosphere via medical fluid pressure, forcing valve membranes <NUM> and <NUM> open, and/or by forming valve membranes <NUM> and <NUM> to be preformed or predomed into a sphere or dome and orienting the dome towards the pneumatic inlet, such that the natrual bias of the membrane itself causes or tends to cause the inlet and outlet valves <NUM> and <NUM> to open when not subjected to positive pneumatic pressure.

Claim 1:
A medical fluid delivery machine (<NUM>) comprising:
a medical fluid pump (<NUM>) including
a pneumatically actuated pump chamber (<NUM>),
first and second pneumatically actuated medical fluid valve chambers (<NUM>, <NUM>) positioned to be inlet and outlet valves to and from the pneumatically actuated pump chamber (<NUM>),
a positive pressure accumulator (<NUM>) storing positive pressure air for delivery to the pneumatically actuated pump chamber (<NUM>) and the first and second pneumatically actuated medical fluid valve chambers (<NUM>, <NUM>),
a pneumatic regulator (<NUM>) located between the positive pressure accumulator and the pneumatically actuated medical fluid valve chambers for setting a desired positive pneumatic pressure,
a first binary valve (240b) located pneumatically between the positive pressure accumulator (<NUM>) and the first pneumatically actuated medical fluid valve chamber (<NUM>),
a second binary valve (240e) located pneumatically between the positive pressure accumulator (<NUM>) and the second pneumatically actuated medical fluid valve chamber (<NUM>), characterised by
a third binary valve (240a) located pneumatically between the first pneumatically actuated medical fluid valve chamber (<NUM>) and atmosphere, and
a fourth binary valve (240f) located pneumatically between the second pneumatically actuated medical fluid valve chamber (<NUM>) and atmosphere; and
a control unit (<NUM>) configured to cause (i) the first binary valve (240b) to close and the third binary valve (240a) to open to enable the first pneumatically actuated medical fluid valve chamber (<NUM>) to fluidically open by venting positive pressure at the first pneumatically actuated medical fluid valve chamber (<NUM>) to atmosphere, and (ii) the second binary valve (240e) to close and the fourth binary valve (240f) to open to enable the second pneumatically actuated medical fluid valve chamber (<NUM>) to fluidically open by venting positive pressure at the second pneumatically actuated medical fluid valve chamber (<NUM>) to atmosphere.