JP2024033781A - Hemodialysis system with variable dialysate flow rate - Google Patents

Abstract

A hemodialysis system with variable dialysate flow rate is provided. A dialyzer, a closed loop blood flow path that transports blood from a patient through the dialyzer and back to the patient, and a dialyzer. A portable hemodialysis system is provided that includes a closed loop dialysate flow path for transporting dialysate therethrough. Preferably, the hemodialysis system includes a sorbent filter in the dialysate flow path. Additionally, the hemodialysis machine includes a blood pump and a pair of dialysate pumps. A processor controls the flow of blood through the blood flow path, and the processor controls flow of dialysate through the dialysate flow path. In addition, the processor stores a patient treatment plan in which the flow rate of dialysate through the dialysate flow path is reduced throughout the patient's treatment to maximize the amount of urea removed by the sorbent filter. do. [Selection diagram] None

Description

The present invention relates to an artificial kidney system for use in providing dialysis. More specifically, the present invention is directed to a hemodialysis system.

Applicants hereby incorporate by reference all patents and published patent applications cited or referred to in this application.

Hemodialysis is a medical procedure used to accomplish the extracorporeal removal of waste products, including creatine, urea, and free water, from a patient's blood, which involves the diffusion of solutes across a semipermeable membrane. be. The inability to properly remove these waste products can lead to kidney failure.

During hemodialysis, a patient's blood is removed by an arterial line, treated by a dialysis machine, and returned to the body by a venous line. Dialysis machines include dialyzers that contain a number of hollow fibers forming a semi-permeable membrane through which blood is transported. In addition, dialysis machines utilize a dialysate fluid that contains appropriate amounts of electrolytes and other essential components (such as glucose) and is also pumped through the dialyzer.

Typically, dialysate is prepared by mixing water and appropriate proportions of acid concentrate and bicarbonate concentrate. Preferably, the acid and bicarbonate concentrates are suitable for use in a dialyzer because the calcium and magnesium in the acid concentrate will precipitate when contacted with high bicarbonate levels in the bicarbonate concentrate. separated until just before final mixing. The dialysate may also contain appropriate levels of sodium, potassium, chlorine, and glucose.

The dialysis process across the membrane is accomplished by a combination of diffusion and convection. Diffusion involves the migration of molecules through random motion from areas of high concentration to areas of low concentration. Convection, on the other hand, typically involves the movement of solutes in response to hydrostatic pressure differences. The fibers, which form a semipermeable membrane, separate plasma from the dialysate and allow waste products, including urea, potassium, and phosphate, to permeate into the dialysate. provides more surface area for diffusion to occur, preventing the transport of larger molecules such as blood cells, polypeptides, and certain proteins.

Typically, dialysate flows in the opposite direction to blood flow within the extracorporeal circuit. Countercurrent flow maintains a concentration gradient across the semi-permeable membrane so as to improve the efficiency of dialysis. In some cases, hemodialysis may provide fluid removal, also referred to as ultrafiltration. Ultrafiltration generally lowers the hydrostatic pressure in the dialysate compartment of a dialyzer, thus allowing water containing dissolved solutes, including electrolytes and other osmotic substances, to cross the membrane from plasma. This is accomplished by allowing the dialysate to travel to the dialysate. In more rare situations, the fluid in the dialysate flow path portion of the dialyzer is higher than the blood flow portion, causing fluid to move from the dialysis flow path to the blood flow path. This is commonly referred to as reverse ultrafiltration. Because ultrafiltration and reverse ultrafiltration can increase risks to the patient, ultrafiltration and reverse ultrafiltration are typically performed while supervised by highly trained medical personnel. be exposed.

Unfortunately, hemodialysis suffers from a number of drawbacks. Arteriovenous fistulas are the most commonly recognized access points. To create a venous fistula, a doctor joins an artery and vein together. This process bypasses the patient's capillaries, so the blood flows rapidly. For each dialysis session, a venous fistula must be punctured using a large needle to deliver blood into and from the dialyzer. Typically, the procedure is performed in an outpatient facility for 3 to 4 hours three times a week. To a lesser extent, patients undergo hemodialysis at home. Home dialysis is typically performed for two hours, six days a week. However, home hemodialysis requires more frequent treatments.

Home hemodialysis still suffers from additional drawbacks. The present home dialysis systems are large, complex, intimidating, and difficult to operate. This equipment requires significant training. Home hemodialysis systems are currently too large and unportable, thereby preventing hemodialysis patients from traveling. Home hemodialysis systems are expensive and require a high initial financial investment, especially compared to in-center hemodialysis, where the patient is not required to pay for the machine. The present home hemodialysis system does not adequately provide for reuse of consumables, making home hemodialysis less economically viable for medical supply suppliers. As a result of the drawbacks mentioned above, very few patients are motivated to undertake the labors of home hemodialysis.

Additionally, hemodialysis systems that utilize sorbent filters have not gained wide acceptance. Unfortunately, sorbent filters are relatively expensive and remove excess post-dialysis ions, namely K+, Ca++, Mg++, and phosphate ( _PO4 ), such as Na+, H+, bicarbonate (HCO3-), Due to the ion exchange that occurs as it is exchanged with harmless or less toxic ions such as and acetate, it can be used quickly.

Therefore, there is a significant need for a hemodialysis system that is portable, lightweight, easy to use, patient-friendly, and thus capable of in-clinic or home use.

It would also be desirable to provide a hemodialysis system that does not have single points of failure within the pump, motor, tubing, or electronics that would put the patient at risk.

In addition, it would be desirable to provide a hemodialysis system that can be used in a variety of modes, such as with or without a filter to clean the dialysate.

Additionally, it would be desirable to operate the hemodialysis system in a manner that maximizes the life of the sorbent filter.

Aspects of the present invention fulfill these needs and provide additional related advantages, as described in the summary below.

According to a first aspect of the invention, an arterial blood line for connecting to an artery of the patient for collecting blood from the patient and a venous blood line for connecting to a vein of the patient for returning blood to the patient. A hemodialysis system is provided that includes a line, a reusable dialyzer, and a disposable dialyzer.

Arterial and venous blood lines may be of typical construction known to those skilled in the art. For example, an arterial blood line may be conventional flexible hollow tubing connected to a needle for collecting blood from a patient's artery. Similarly, the venous blood line may be a conventional flexible tube and needle for returning blood to the patient's veins. A variety of constructs and surgical techniques may be employed to gain access to the patient's blood, including intravenous catheters, arteriovenous fistulas, or synthetic grafts.

Preferably, the disposable dialyzer has a construction and design known to those skilled in the art, including a blood flow path and a dialysate flow path. The term "channel" is intended to refer to one or more fluid conduits, also referred to as passageways, for conveying fluid. The conduit may be constructed in any manner as can be determined by one skilled in the art, including flexible medical tubing or non-flexible hollow metal or plastic housings and the like. The blood flow path transports blood in a closed loop system by connecting to arterial and venous blood lines for transporting blood from the patient to the dialyzer and back to the patient. Meanwhile, the dialysate flow path transports dialysate in a closed loop system from the dialysate supply to the dialyzer and back to the dialysate supply. Both the blood flow path and the dialysate flow path pass through the dialyzer, but the flow paths are separated by the semi-permeable membrane of the dialyzer.

Preferably, the hemodialysis system contains a reservoir for storing dialysis solution. The reservoir connects to the dialysate flow path of the hemodialysis system to form a closed loop system for conveying dialysate from the reservoir to the dialyzer of the hemodialysis system and back to the reservoir. Alternatively, the hemodialysis system has two (or more) dialysate reservoirs, which may alternatively be placed within the dialysate flow path. When one reservoir holds contaminated dialysate, dialysis treatment can continue using the other reservoir while the reservoir with contaminated dialysate is emptied and refilled. . The reservoir may be of any size as required by the clinician to perform appropriate hemodialysis treatment. However, it is preferred that the two reservoirs be of the same size and small enough to allow the dialysis machine to be easily portable. Acceptable reservoirs are between 0.5 liters and 6.0 liters in size. If the hemodialysis system includes only one reservoir, an acceptable reservoir has a volume of 12.0 liters.

The hemodialysis system preferably has one or more heaters thermally coupled to the reservoir for heating dialysate stored within the reservoir. In addition, the hemodialysis system includes a temperature sensor to measure the temperature of the dialysate within the reservoir. The hemodialysis system preferably has a fluid level sensor for detecting the level of fluid within the reservoir. The fluid level sensor may be any type of sensor for determining the amount of fluid within a reservoir. Acceptable level sensors include gravimetric sensors, such as magnetic or mechanical floating type sensors, conductive sensors, ultrasonic sensors, optical interfaces, and scales or load cells for measuring the weight of dialysate in the reservoir. include.

Preferably, dialysis includes three primary pumps. First and second "dialysate" pumps are connected to the dialysate flow path for pumping dialysate from the reservoir to the dialyzer and back to the reservoir through the dialysate flow path. Preferably, the first pump is positioned in the dialysate flow path "upward" (meaning "forward in the flow path") from the dialyzer, while the second pump is positioned "downward" from the dialyzer. (meaning "later in the flow path") positioned within the dialysate flow path. Meanwhile, a third primary pump of the hemodialysis system is connected to the blood flow path. The "blood" pump pumps blood from the patient through an arterial blood line, through a dialyzer, and through a venous blood line for return to the patient. Preferably, a third pump is positioned within the blood flow path upward from the dialyzer.

The hemodialysis system may also contain one or more sorbent filters to remove toxins that have percolated from the plasma through the semi-permeable membrane into the dialysate. Filter materials for use in filters are well known to those skilled in the art. For example, suitable materials include resin beds that include zirconium-based resins. Acceptable materials are also described in US Patent No. 8,647,506 and US Patent Publication No. 2014/0001112.

In a first embodiment, a sorbent filter is connected to the dialysate flow path downstream from the dialyzer to remove toxins in the dialysate prior to conveying the dialysate back to the reservoir. be done. In a second embodiment, the filter is external to the closed-loop dialysate flow path, but is instead provided in a separate closed-loop "filter" flow path that selectively connects to either one of the two dialysate reservoirs. located within. For this embodiment, preferably the hemodialysis system includes a filter flow path and an additional fluid pump for pumping contaminated dialysate through the filter.

Preferably, the hemodialysis system includes two additional flow paths in the form of a "drain" flow path and a "fresh dialysate" flow path. The drain flow path includes one or more fluid drain lines for draining the contaminated dialysate reservoir, and the fresh dialysate flow path connects the fresh dialysate to the fresh dialysate supply. one or more fluid fill lines for conveying fluid from the reservoir to the reservoir. One or more fluid pumps may be connected to the drain flow path and/or the fresh dialysate flow path to convey fluids to their intended destination.

In addition, hemodialysis systems are used to control the flow of blood through the blood flow path, to control the flow of dialysate through the dialysate flow path, and to control the flow of used dialysate through the filter flow path. Includes a plurality of fluid valve assemblies for controlling flow. The valve assembly may be any type of electromechanical fluid valve construction, as can be determined by one of ordinary skill in the art, including, but not limited to, conventional electromechanical two-way fluid valves and three-way fluid valves. . A two-way valve is any type of valve with two ports, including an inlet port and an outlet port, where the valve simply allows the flow of fluid through a fluid path or interrupt. Conversely, a three-way valve has three ports and functions to block fluid flow in one fluid pathway while opening fluid flow in another pathway. In addition, the dialysis machine valve assembly includes a safety pinch valve, such as a pinch valve, connected to the venous blood line to selectively allow or block the flow of blood through the venous blood line. May include. A pinch valve is provided to pinch the venous blood line, thereby preventing blood flow back to the patient if a hazardous condition is detected.

Preferably, the hemodialysis system contains a sensor for monitoring hemodialysis. To achieve this goal, the dialysis machine preferably includes at least one flow sensor connected to the dialysate flow path for detecting fluid flow (volume and/or velocity) within the dialysate flow path. has. In addition, the dialysis machine includes one or more pressure sensors for detecting pressure within the dialysate flow path, or at least an occlusion sensor for detecting whether the dialysate flow path is blocked. It is preferable to contain. Preferably, the dialysis machine also has one or more sensors for measuring pressure and/or fluid flow within the blood flow path. The pressure and flow rate sensors may be separate components or the pressure and flow rate measurements may be made by a single sensor.

In addition, the hemodialysis system monitors the flow of dialysate through the dialysate flow path and detects whether blood is improperly diffusing through the semi-permeable membrane of the dialyzer into the dialysate flow path. Preferably, a blood leak detector ("BLD") is included. In a preferred embodiment, the hemodialysis system includes a blood leak sensor assembly that incorporates a light source that emits light through the dialysate flow path and a light sensor that receives the light that is being emitted through the dialysate flow path. After passing through the dialysate flow path, the received light is then analyzed to determine whether the light has been modified to reflect possible blood in the dialysate.

The dialysis machine preferably includes additional sensors, including an ammonia sensor and a pH sensor for detecting the levels of ammonia and pH in the dialysate. Preferably, the ammonia sensor and pH sensor are in the dialysate flow path immediately downstream of the filter. In addition, the dialysis machine includes an air bubble sensor connected to the arterial blood line and an air bubble sensor connected to the venous blood line for detecting whether gaseous bubbles are forming within the blood flow path. and possess.

The hemodialysis system has a processor that contains dedicated electronics to control the hemodialysis system. The processor contains power management and control electrical circuitry connected to the pump motor, valves, and dialysis machine sensors to control the proper operation of the hemodialysis system.

It has been found that reducing the flow rate of dialysate through the dialysate flow path increases the capacity of the sorbent filter's zirconium phosphate to capture ammonium from urea. Because urea is high at the beginning of a patient's treatment and then decreases as it is removed during treatment, a constant urea concentration starts at a high flow rate and reduces this over the course of treatment. request. Advantageously, any loss in urea clearance from reducing dialysate flow rate can be compensated for by increasing the duration of the dialysis treatment. Thus, in a preferred embodiment, the processor of the hemodialysis system includes a memory that stores one or more patient treatment plans by which a patient is treated. According to the patient treatment plan, the dialysate flow rate through the dialysate flow path is not static throughout the treatment. Instead, the dialysate flow rate decreases throughout the patient's treatment. The reduction in dialysate flow rate may be gradual. Alternatively, the dialysate flow rate may decrease in any manner, such as linearly, exponentially, inversely, polynomially, or other relationships that provide for decreasing the dialysate flow rate over time.

Specifically, each patient treatment plan includes a total period "T" for treating the patient, which in turn includes multiple time periods T1, T2, T3, etc. Contains time partitions. The patient treatment plan further includes a plurality of flow rates, including a high flow rate, operating over at least time periods T1, time periods T2, time periods T3, etc. As will be understood by those skilled in the art, if the reduction in dialysate flow rate is changed slowly, such as in a linear or polynomial fashion, the period per time segment can be quite small.

Preferably, dialysate treatment begins at a higher dialysate flow rate of 400-800 ml/min and ends at a lower flow rate of 100-500 ml/min. More preferably, the dialysis treatment begins at a higher dialysate flow rate of 450-800 ml/min and ends at a lower flow rate of 100-450 ml/min. In a preferred embodiment, the patient treatment plan lasts for 2-6 hours, begins treatment at a dialysate flow rate of approximately 400-600 ml/min, and decreases linearly until ending at a flow rate of 200-300 ml/min. do. In an even more preferred embodiment, the patient treatment plan begins treatment with a dialysate flow rate of approximately 500 ml/min and decreases linearly over 4 hours until ending at a flow rate of 250 ml/min.

The dialysis machine provides a hemodialysis system that is portable, lightweight, easy to use, patient-friendly, and capable of in-home use.

Additionally, the present hemodialysis system provides an extraordinary amount of control and monitoring not previously provided by hemodialysis systems, providing improved patient safety.

The hemodialysis system also maximizes the amount of urea that can be removed by the sorbent filter.

Other features and advantages of the invention will be apparent to those skilled in the art upon reading the detailed description that follows in conjunction with the drawings.
The present invention provides, for example, the following items.
(Item 1)
A hemodialysis system with variable flow rate, the system comprising:
a mechanical casing;
an arterial blood line for connecting to a patient's artery for collecting blood from the patient;
a venous blood line for connecting to a patient's vein for returning blood to the patient;
A dialysis machine,
a blood flow path, the blood flow path connected to the arterial blood line and the venous blood line for conveying blood from the patient to the dialyzer and back to the patient; and,
a reservoir for storing dialysate;
a dialysate flow path, the dialysate flow path being isolated from the blood flow path and connected to the reservoir and the dialyzer for conveying dialysate from the reservoir to the dialyzer; a liquid flow path;
at least one dialysate pump for pumping dialysate through the dialysate flow path;
a blood pump for pumping blood through the blood flow path;
a dialysate flow sensor in the dialysate flow path that measures the flow rate of dialysate through the dialysate flow path;
a control processor connected to the dialysate flow sensor and the at least one dialysate pump, the control processor having a memory for storing a patient treatment plan by which a patient is to be treated; the treatment plan includes a dialysate flow rate during treatment of the patient, the dialysate flow rate being decreased over a period of time T(total) for treating the patient; Hemodialysis system with.
(Item 2)
The hemodialysis system with variable flow rate according to the above item, wherein the dialysate flow rate includes a high flow rate and a low flow rate, the low flow rate being less than 75% of the high flow rate.
(Item 3)
A hemodialysis system with variable flow rate according to any of the preceding items, wherein the patient treatment plan comprises decreasing the dialysate flow rate in a linear manner.
(Item 4)
A hemodialysis system with variable flow rate according to any of the preceding items, wherein the dialysate flow rate decreases progressively and includes a high flow rate and a low flow rate.
(Item 5)
Hemodialysis system with variable flow rate according to any one of the above items, wherein the dialysate flow rate comprises a high flow rate of 400-800 ml/min and a low flow rate of 100-400 ml/min.
(Item 6)
The control processor causes the dialysate pump to pump 400-800 ml/min of dialysate through the dialysate flow path for at least 0.5 hours; A hemodialysis system with variable flow rate according to any of the preceding items, which pumps 100-400 ml/min of dialysate through the flow path for at least 0.5 hours.
(Item 7)
Hemodialysis system with variable flow rate according to any of the preceding items, further comprising a sorbent filter connected to the dialysate flow path for removing uremic toxins from the dialysate.
(Summary)
Portable hemodialysis comprising a dialyzer, a closed loop blood flow path that transports blood from a patient through the dialyzer and back to the patient, and a closed loop dialysate flow path that transports dialysate through the dialyzer. A system is provided. Preferably, the hemodialysis system includes a sorbent filter in the dialysate flow path. Additionally, the hemodialysis machine includes a blood pump and a pair of dialysate pumps. A processor controls the flow of blood through the blood flow path, and the processor controls flow of dialysate through the dialysate flow path. In addition, the processor stores a patient treatment plan in which the flow rate of dialysate through the dialysate flow path is reduced throughout the patient's treatment to maximize the amount of urea removed by the sorbent filter. do.

FIG. 1 is a flowchart illustrating a first embodiment of a hemodialysis system.

FIG. 2 is the flowchart of FIG. 1 illustrating an embodiment in which dialysate bypasses the filter by flowing through a bypass channel.

FIG. 3 is the flowchart of FIG. 1 illustrating an embodiment in which dialysate flows through a filter in a closed loop dialysate flow path that incorporates a first reservoir.

FIG. 4 is the flowchart of FIG. 1 illustrating an embodiment in which dialysate flows through a filter in a closed loop dialysate flow path that incorporates a second reservoir.

FIG. 5 is a flowchart illustrating a second embodiment of a hemodialysis system that includes a closed loop filter flow path filtering fluid within a first reservoir.

FIG. 6 is a flowchart illustrating a second embodiment of the hemodialysis system shown in FIG. 5, including a filter channel filtering fluid in a second reservoir.

FIG. 7 illustrates an embodiment of a hemodialysis system in which dialysate from an external source is supplied to one of the system's reservoirs and used dialysate is directed to a storage bag or drain. This is a flowchart.

FIG. 8 is a flowchart illustrating an embodiment of the hemodialysis system of FIG. 7 in which a sorbent filter is introduced into the system to provide closed loop operation.

FIG. 9 is a block diagram illustrating a blood pump, dialysate pump, and flow sensor connected to a processor of a hemodialysis system.

FIG. 10 is a graph illustrating a patient treatment plan with steps to reduce dialysate flow rate.

FIG. 11 is a graph illustrating a second patient treatment plan that involves decreasing dialysate flow rate.

FIG. 12 is a graph illustrating a third patient treatment plan that involves decreasing dialysate flow rate.

FIG. 13 is a graph illustrating a fourth patient treatment plan that involves decreasing dialysate flow rate.

DETAILED DESCRIPTION OF THE INVENTION Although the present invention is capable of embodiment in various forms, such as those illustrated in the drawings, it is understood that the present disclosure is to be regarded as illustrative of the invention, and that the invention is not shown in the figures. The present preferred embodiments of the invention will be described with the understanding that it is not intended to be limited to the specific embodiments presented.

As illustrated in most detail in FIGS. 1-8, the hemodialysis system includes a blood flow path 53 and a dialysate flow path 54. The hemodialysis system further includes a reusable dialysis machine and disposable components for performing hemodialysis. Blood flow path 53 includes an arterial blood line 1 for connecting to a patient's artery for collecting blood from the patient, and a venous blood line 14 for connecting to a patient's vein for returning blood to the patient. including. Arterial blood line 1 and venous blood line 14 may be of typical construction known to those skilled in the art.

Blood flow path 53 transports blood from the patient in a closed loop system by connecting to arterial blood line 1 and from venous blood line 14 to the patient for conveying blood from the patient through dialyzer 8 and back to the patient. transport. Preferably, the hemodialysis system includes a heparin supply 6 and a heparin pump connected to the blood flow path 1. Heparin pumps deliver small amounts of heparin anticoagulant into the bloodstream, reducing the risk of blood clotting within the machine. The heparin pump can take the form of a linearly operated syringe pump, or it can be a bag connected to a small peristaltic or infusion pump.

The hemodialysis system includes a dialyzer 8 within dialysate flow path 54, of construction and design known to those skilled in the art. Preferably, dialyzer 8 comprises a number of hollow fibers forming a semi-permeable membrane. A suitable dialyzer is available from Fresenius Medical Care, Baxter International, Inc. , Nipro Medical Corporation, and other manufacturers of hollow fiber dialyzers. Both the blood flow path and the dialysate flow path have an inlet for receiving dialysate, an outlet for discharging dialysate, an inlet for receiving blood from the patient, and an inlet for receiving blood from the patient. It proceeds through a dialyzer 8, which has an outlet for returning the dialysis fluid to the dialysis machine. Preferably, the dialysate flows in a direction opposite to the blood flowing through the dialyzer, with the dialysate flow path separated from the blood flow path by a semi-permeable membrane (not shown). As illustrated in FIGS. 1-6 and explained in more detail below, dialysate flow path 54 allows dialysate to flow from reservoir (17 or 20) to dialyzer 8 and to reservoir (17 or 20). 20) transporting the dialysate in a closed loop system where it is pumped back into the system. Blood flow path 53 and dialysate flow path 54 both pass through dialyzer 8 but are separated by a semi-permeable membrane of the dialyzer.

Preferably, the hemodialysis system includes three primary pumps (5, 26, and 33) for pumping blood and dialysate. For purposes of this specification, the term "pump" is intended to refer to both pump actuators, which use suction or pressure to move fluid, and pump motors, which mechanically move the actuators. means. Suitable pump actuators include impellers, pistons, diaphragms, lobes of lobe pumps, screws of screw pumps, rollers or linearly movable fingers of peristaltic pumps, or any Other mechanical constructs may also be included. On the other hand, the pump motor is an electromechanical device for moving the actuator. The motor may be connected to the pump actuator by a shaft or the like. In a preferred embodiment, the dialysate and/or blood flows through conventional flexible tubing, and the pump actuators each include a "roller" or "shoe" that compresses the flexible tubing. It consists of a peristaltic pump mechanism, including a rotor, with several cams attached to the outer periphery of the rotor, in the form of , "wipers", or "lobes". As the rotor rotates, the portion of the tube that is under compression is pinched closed (ie, "occluded"), forcing fluid to be pumped through the tube. Additionally, fluid flow is induced through the tube as it opens to its natural state after passing the cam.

The first and second primary pumps (26 and 33) pump dialysate through the dialysate flow path from the reservoir (17 or 20) to the dialyzer 8 and back to the reservoir (17 or 20). connected to the dialysate flow path. The first pump 26 is connected to the dialysate flow path “upstream” (meaning “forward in the flow path”) from the dialyzer 8 , while the second pump 33 is connected “downstream” from the dialyzer 8 . ” (meaning “rear in the flow path”) to the dialysate flow path. Meanwhile, a third primary pump 6 of the hemodialysis system is connected to the blood flow path. A third pump 6, also referred to as a blood pump, pumps blood from the patient through the arterial blood line, through the dialyzer 8, and through the venous blood line for return to the patient. Preferably, a third pump 6 is connected to the blood flow path upstream from the dialyzer. A hemodialysis system may contain more or less than three primary pumps. For example, dialysate may be pumped through dialyzer 8 utilizing only a single pump. However, it is preferred that the hemodialysis system contains two pumps, including a first pump 26 upstream from the dialyzer 8 and a second pump 33 downstream from the dialyzer 8.

Preferably, the hemodialysis system contains one or more reservoirs (17 and 20) for storing dialysis solution. If the system includes two reservoirs, both reservoirs (17 and 20) may be connected to dialysate flow path 54 simultaneously to form one large source of dialysate. Alternatively, the hemodialysis system introduces one of the two reservoirs (17 or 20), but not both, into the dialysate flow path 54 and directs dialysate from one of the two reservoirs to the dialyzer. , and a valve assembly 21 to form a closed loop system for conveyance back to its reservoir. After the dialysate in the first reservoir 17 has been used and is no longer sufficiently clean or possesses the appropriate chemistry, the valve 21 of the hemodialysis system removes the dialysate from the dialysate flow path. The control is such that the reservoir 17 is removed and a second reservoir 20 containing fresh dialysate 75 is substituted into the dialysate flow path. Therefore, when one reservoir holds contaminated dialysate 76 and the reservoir needs to be emptied and refilled with freshly generated dialysis fluid 75, the dialysis treatment uses the other reservoir. and then continue.

In this manner, the hemodialysis system may switch between each reservoir 17 and 20 multiple times over the course of treatment. Additionally, the presence of two reservoirs, as opposed to one reservoir, allows for flow rate adjustment for pump calibration or ultrafiltration measurements while isolating the other reservoir while it is being drained or filled. enable measurement. Although the reservoir may be any size as required by the clinician to perform a suitable hemodialysis treatment, preferred reservoirs have a volume of 0.5 liters to 5.0 liters.

The hemodialysis system is also connected to a dialysate flow path 54 (also referred to herein as a "filter") for removing toxins that have permeated from the plasma through the semi-permeable membrane into the dialysate. ) Contains an adsorbent filter. In a first embodiment, the filter 36 is configured in the dialysate flow path downstream from the dialyzer to remove toxins transferred into the dialysate by the dialyzer prior to conveying the dialysate to the reservoir. 54. Filter materials for use with dialysis machines are well known to those skilled in the art. For example, suitable materials include resin beds that include zirconium-based resins. Preferably, the filter has a housing containing layers of zirconium oxide, zirconium phosphate, and carbon. Acceptable materials are described in US Patent No. 8,647,506 and US Patent Application Publication No. 2014/0001112. Other acceptable filter materials can be developed and utilized by those skilled in the art without undue experimentation. The filter housing may or may not contain a vapor film that is not liquid, in particular not dialysate liquid flowing through the filter, and capable of releasing gases.

If the hemodialysis system includes a sorbent filter, the dialysate flow path 54 preferably incorporates safety features in the form of an ammonium sensor 37 and a pH sensor 38. These sensors may be located immediately downstream of the sorbent cartridge 36 or one or more reservoirs. Once the sorbent filter 36 is depleted, the filter 36 may begin to release ammonium ions as a result of the filtration chemistry. At some level, ammonium ions in dialysis fluids can be harmful to patients. Preferably, ammonium ion sensor 37 measures the amount of ammonium ions in parts per million (ppm). When the measured value reaches a range of approximately 5-20 ppm, a warning condition is activated and treatment with the present dialysate is stopped. The dialysis fluid can be drained and dialysis treatment can be continued by using fresh dialysis fluid using an alternate reservoir. Similarly, pH sensor 38 also acts as a safety feature and assists in measuring ammonium ions. As the pH of the dialysis fluid changes, the balance of ammonia (NH3) and ammonium ions (NH4+) may also change. If the pH of the dialysis fluid is measured to be outside the range of approximately 6.4-7.8 pH, a warning condition may be activated and the dialysis fluid in use may be drained. Can be done.

It is also preferred that the hemodialysis system has a reagent bag 39 and a pump 40 for introducing reagents into the dialysate flow path 54 immediately after the sorbent filter 36. Reagent bag 39 holds a concentrated solution of salts and ions for reinjecting dialysis fluid into the filter. Through its action of filtering waste, the sorbent filter 36 also removes beneficial ions such as calcium and salts from the dialysis fluid. Before the filtered dialysis fluid can be recirculated, it must be reinfused with calcium and salts so that the dialysis fluid does not draw these beneficial ions from the patient's blood. Preferably, reagent bag 39 will hold 1-3 liters of concentrated reagent. Reagent pump 40 can be any type of pump, such as a peristaltic pump or a diaphragm pump. A conductivity sensor 41 is positioned in the dialysate flow path 54 immediately after the reagent bag 39 to ensure that the hemodialysis system is introducing the proper amount of salts and ions into the dialysate. It's okay to be hit. Conductivity sensor 41 serves as a safety feature, measuring the total dissolved solids of the regenerated dialysate. If it is detected that the total dissolved solids are not within the prescribed range, operation of pump 40 can be increased or decreased, or alternatively, treatment can be stopped completely. Can be done. For example, if a fault condition is detected within the dialysis fluid, the fluid may be redirected through the bypass passageway 30 by three-way valves 29 and 32 so that the dialysate does not come into contact with the patient's blood within the dialyzer. can. More specifically, three-way valve 29 directs dialysis fluid to the inlet of the dialyzer, and three-way valve 32 directs dialysate from the dialysate outlet back to dialysate flow path 54 . However, if a fault condition is detected in the dialysis fluid, such as too low a temperature or excessive ammonium ions are detected in the dialysate, the dialysis fluid is diverted to the bypass passage 30 by the three-way valves 29 and 32. is diverted to bypass the dialyzer 8 through the dialyzer 8.

With respect to the embodiments illustrated in FIGS. 1-4, the hemodialysis system includes a drainage flow path 55 for disposing of waste dialysate from the reservoirs (17 and 20). In the embodiment illustrated in FIGS. 1-4, the drainage channel 55 is connected to both reservoirs (17 and 20). The waste dialysate may be drained through the drainage channel 5 through gravity feed, or as a hemodialysis system may be selected by the person skilled in the art to pump the used dialysate to be discarded. Note that any type of pump 44 may be included in a conventional building sewer line 45 or the like.

With respect to the embodiments illustrated in FIGS. 1-4, the hemodialysis system preferably includes a dialysate fluid source 46 for refilling each of the reservoirs 17 and 20. Preferably, the dialysate fluid source includes a supply of clean water 46 that is mixed with reagents (48 and 50) to provide dialysate of desired properties. In a preferred embodiment, the clean water supply 46 is a reverse osmosis ("RO") system located adjacent to the device that produces clean water and then adds chemical concentrates to produce dialysate fluid. ) provided by the machine. Fluid is supplied to the reservoirs (17 and 20) through a "fresh dialysate" channel 56. Preferably, the hemodialysis system also includes a source of concentrated reagents (48 and 50) that can be stored within a disposable bag. Preferably, the concentrated reagent contains one or more of the following: carbonate solution, bicarbonate solution, acidic solution, lactic acid solution, salt solution. It is necessary to separate some of the reagents into two bags (48 and 50) to prevent unwanted interactions or precipitation of solutes. Concentrated reagent sources (48 and 50) are connected to supply line 46 by pumps (47 and 49). Activation of the pumps (47 and 49) introduces concentrated reagent into the water supply and provides dialysate to the reservoirs (17 and 20).

As an alternative to using a sorbent filter 36, the hemodialysis system includes a complementary "bypass" flow path 35 that selectively conveys dialysis around the sorbent filter 36. The bypass flow path includes a three-way valve 34 upstream of the filter. The three-way valve 34 is switched to direct the dialysis fluid through the sorbent filter 36, or alternatively, the three-way valve 34 is switched to direct the dialysate through the bypass flow path 35 to avoid the sorbent filter 36. Can be switched. For example, if a sorbent filter is not available, or if a sorbent filter is becoming obsolete, or if a sorbent filter is not required for a particular patient treatment, the three-way valve 34 The fluid is switched to be directed to follow the bypass flow path 35.

In the alternative embodiment illustrated in FIGS. 5 and 6, the sorbent filter 71 is located outside the closed loop dialysate flow path. The hemodialysis system includes a separate closed-loop "filter" flow path 57 that selectively connects to either one of the two dialysate reservoirs 17 or 20, with a filter 71 in series within the closed-loop filter flow path 57. It is positioned in Preferably, the dialysis machine includes an additional fluid pump 58 for pumping contaminated dialysate through the filter flow path and filter 71. As illustrated in FIGS. 5 and 6, the preferred filter flow path 57 includes a three-way valve 43 that determines the reservoir to which contaminated dialysate is drained. For example, FIG. 5 illustrates a three-way valve 43 that connects reservoir 20 to filter flow path 57, but not reservoir 17. FIG. 6 illustrates a three-way valve 43 connecting reservoir 17 to filter flow path 57, but not reservoir 20. The filter flow path may include a pump 58 or dialysate may dispense contaminated dialysate from reservoir 17 or 20 through gravity feed. In addition, filter flow path 57 preferably includes a pressure sensor 59, a check valve 60, an ammonium sensor 69, and a pH sensor 70.

This embodiment of a hemodialysis machine includes a system for introducing reagents into the filter flow path. As illustrated in FIGS. 5 and 6, filter flow path 57 may include a first reagent source 61 containing salts and a second reagent source 65 containing bicarbonate and lactic acid solution. good. These reagents are introduced into the filter flow path using pumps 62 and 66 and mixers 63 and 67. Preferably, the filter flow path is also equipped with a safety feature in the form of an ammonium sensor 69 to ensure that the filter 71 is not used and does not introduce unacceptable ammonium ions into the dialysate. , conductivity sensors 64 and 68 that monitor whether reagents are properly introduced into the cleaned dialysate to provide the appropriate amount of beneficial ions. Finally, the filter flow path 57 now includes a pair of filters that are opened and closed to ensure that the cleaned dialysate is returned to the reservoir from which the contaminated dialysate is being drained. Includes check valves 51 and 52.

FIG. 7 illustrates an embodiment of a hemodialysis system in which the system is operated in single pass mode. Dialysate is introduced into the machine from a dialysate source 46 maintained at the desired temperature by heater 23 through a fresh dialysate flow path to reservoir 17 . From this treatment, dialysate from the first reservoir 17 is circulated through the dialyzer 8 using pumps 26 and 33. Thereafter, the used dialysate is then directed to a receiver for storing waste water 55 or waste liquid drainage. Load cells 81 and 82 and/or level sensors 15 may be provided to measure the dialysate source 46 and the resulting wastewater 55. Further, the dialysate flow path may include a flow sensor 25, a pressure sensor 27, and a sample port 79.

FIG. 8 illustrates yet an additional embodiment of a hemodialysis system operating in a recirculation mode in which dialysate flows through a sorbent filter 36 in a closed loop system. As in other embodiments, blood flow path 53 connects arterial blood line 1 and venous blood line 14 to the patient to convey blood from the patient to the dialyzer and back to the patient. Transports blood in a closed loop system. Dialysate is stored in reservoir 17 with the level of the dialysate measured by level sensor 15 and load cell 19 and the temperature of the dialysate maintained by heater 23 . Dialysate is recirculated through dialyzer 8 and sorbent cartridge 36 using pumps 26 and 33. The dialysate is then sent back to the same reservoir 17 through the dialysate flow path 54.

In the embodiment illustrated in FIG. 8, the dialysate flow path includes a degasser 80 located downstream of the sorbent filter 36. The sorbent filter 36 has an air inlet, which in turn has a filter 36a, a pressure sensor, and a pump 44. Adsorbent regeneration degassing may be accomplished by introducing a flow of air through an air inlet into the regenerated dialysate, substantially free of _CO2 . Preferably, pump 44 introduces a flow of air into sorbent filter 36 at approximately the same flow rate as the flow rate of liquid through the dialysate flow path. The combined air/liquid fluid may then be exposed to a hydrophobic membrane within the degasser 80, where the gas freely exits the system, but the liquid continues to flow through the dialysate flow path. .

In the embodiment illustrated in FIG. 8, chemical concentrate sources 48 and 50 are optionally added to the fluid leaving the sorbent filter in order to maintain the appropriate chemicals in the dialysate. provided. Preferably, the first reagent source 48 contains salts and the second reagent source 50 contains bicarbonate or carbonate and a lactic acid solution. The chemical concentrate is introduced into the dialysate flow path using chemical concentrate pumps 47 and 49 where the clean water and chemical concentrate are mixed using mixers 63 and 67. Again, the dialysate flow path may include a flow sensor 25, a pressure sensor 27, and a sample port 79. Preferably, the dialysate flow path also includes a conductivity sensor 41 located between the second mixer 67 and the reservoir 17 and an ammonia sensor 37 located between the reservoir 17 and the dialyzer 8. , a pH sensor 38, and a combined conductivity/temperature sensor 24. A control processor is connected to various sensors and pumps to control hemodialysis treatment. Also referring to FIGS. 9-13, the control processor preferably reduces the dialysate flow rate throughout the treatment, as described below.

Still referring to FIGS. 1-8, the hemodialysis system preferably has a heater 23, thermally connected to the dialysate flow path or reservoir, for heating the dialysate to a desired temperature. For example, in certain embodiments illustrated in FIGS. 1-6, a single heater 23 is thermally coupled to the dialysate flow path downstream of both reservoirs (17 and 20). However, hemodialysis may include additional heaters, and one or more heaters may be in different locations. For example, in an alternative embodiment, the hemodialysis system includes two heaters, a single heater thermally coupled to each reservoir. The one or more heaters preferably include resistors that are electrically activated and produce heat as electrical current is passed through them.

In addition, hemodialysis systems possess various sensors for monitoring hemodialysis, particularly the blood flow path and the dialysate flow path. To achieve this goal, the hemodialysis system preferably includes one or more devices connected to the dialysate flow path for detecting fluid flow (volume and/or velocity) within the dialysate flow path. It has a flow sensor 25 exceeding . In addition, it is preferred that the hemodialysis system contains one or more pressure or occlusion sensors (9 and 27) for detecting the pressure within the dialysate flow path. Preferably, the hemodialysis system also has one or more sensors for measuring pressure (4 and 7) and/or fluid flow 11 within the blood flow path.

Preferably, the hemodialysis system includes temperature sensors (22, 24, and 28) for measuring dialysate temperature throughout the dialysate flow path. In addition, the hemodialysis system has level sensors to detect the level of fluid in the reservoirs (17 and 20). Preferred level sensors may include capacitive fluid level sensor (15 and 18) embodiments in which the weight and therefore the level of dialysate in each reservoir 17 and 20 is determined by a level sensor (16 or 19) connected to the processor. be measured.

In addition, the hemodialysis system monitors the flow of dialysate through the dialysate flow path and detects whether blood is improperly diffusing through the semi-permeable membrane of the dialyzer into the dialysate flow path. Preferably, a blood leak detector 31 is included.

Preferably, the hemodialysis system also includes a first pinch valve 2 connected to the arterial blood line 1 for selectively allowing or blocking the flow of blood through the venous blood line. , a second pinch valve 13 connected to the venous blood line 14 for selectively allowing or blocking the flow of blood through the venous blood line. Pinch valves are provided to pinch the arterial blood line 1 and the venous blood line 14 and prevent blood flow back to the patient if either of the sensors detects a dangerous condition. be done. Subject to further additional safety features, the hemodialysis system includes blood line air bubble sensors (3 and 12) to detect air bubbles following the arterial line (blood leak sensor 3) or the venous line (blood leak sensor 12). to detect whether the process is progressing in the opposite direction. Furthermore, the blood flow path 53 may include an air bubble trap 10 having a pocket of pressurized air inside the plastic housing. Air bubbles rise to the top of the bubble trap while blood continues to flow to the bottom outlet of the trap. This component reduces the risk of air bubbles progressing into the patient's blood.

To control the flow and direction of blood and dialysate through the hemodialysis system, the hemodialysis system employs various fluid valves to control the flow of fluid through the various flow paths of the hemodialysis system. include. The various valves include pinch valves and two-way valves, which must be opened or closed, and three-way valves, which divert dialysate through the desired flow path as intended. In addition to the valves identified above, the hemodialysis system includes a three-way valve 21, located at the outlet of the reservoir, which determines from which reservoir (17 or 20) dialysate is passed through the dialyzer 8. An additional three-way valve 42 determines the reservoir to which the used dialysate is pumped. Finally, two-way valves 51 and 52 (which may be pinch valves) are located at the inlets of the reservoirs, allowing or blocking the supply of fresh dialysate to the reservoirs (17 and 20). Of course, alternative valves may be employed, as can be determined by one skilled in the art, and the invention is not intended to be limited to the specific two-way or three-way valves identified. .

Additionally, the hemodialysis system includes a processor 77 and a user interface (not shown). The processor is for controlling the hemodialysis system, including hardware and software and power management circuitry connected to the pump motors, sensors, valves, and heaters for controlling the proper operation of the hemodialysis system. Contains dedicated electronic equipment. The processor monitors each of the various sensors to ensure that the hemodialysis treatment is proceeding according to a preprogrammed procedure entered into the user interface by a medical professional. The processor incorporates hardware and software, as may be determined by one of ordinary skill in the art, to monitor various sensors and provide automated or directed control of heaters, pumps, and pinch valves. It may be a general purpose computer or microprocessor, including: The processor may be located within the circuit board electronics or within an integrated processing unit of multiple circuit boards and memory cards.

Although not shown, the hemodialysis system also includes a power supply for providing power to the processor, user interface, pump motor, valves, and sensors. The processor connects the dialysis machine sensors (reservoir level sensors (15, 16, 18, and 19), blood leak sensor 31, ammonia sensor 37, and pressure and flow rate sensors (4, 7) by conventional electrical circuitry. , 9, 11, 25, and 27), temperature sensors (22, 24, and 28), and blood line bubble sensors (3 and 12)), pumps (5, 6, 26, 33, 40, 44, 47, and 49), and pinch valves (2 and 13).

In operation, the processor controls the activation and rotational speed of the pump motor, which in turn controls the pump actuator and, in turn, the pressure and fluid velocity of blood through the blood flow path and dialysis through the dialysate flow path. It is electrically connected to first, second, and third primary pumps (5, 26, and 33) for controlling liquid pressure and fluid velocity. By independently controlling the operation of dialysate pumps 26 and 33, the processor can maintain, increase, or decrease the pressure and/or fluid flow within the dialysate flow path within the dialyzer. Also, by independently controlling all three pumps, the processor controls the pressure differential across the semi-permeable membrane of the dialyzer to maintain a predetermined pressure differential (zero, positive, or negative). Or a predetermined pressure range can be maintained. For example, most hemodialysis is performed using zero or near-zero pressure differential across semi-permeable membranes, and to achieve this goal, the processor uses the desired zero or near-zero pressure. The pump can be monitored and controlled to maintain the difference. Alternatively, the processor monitors the pressure sensor, controls the pump motor, and in turn controls the pump actuator to adjust the positive pressure in the blood flow path within the dialyzer relative to the pressure in the dialysate flow path within the dialyzer. may be increased and maintained. Advantageously, this pressure differential can be influenced by the processor to provide ultrafiltration and transfer of free water and dissolved solutes from the blood to the dialysate.

In a preferred embodiment, the processor monitors the blood flow sensor 11 and controls the flow rate of the blood pump. This uses a dialysate flow sensor 25 to control the flow rate of dialysate from the upstream dialysate pump. The processor then uses the reservoir level sensors (15, 16, 18, and 19) to control the flow rate from the downstream dialysate pump 33. Changes in fluid level (or volume) within the dialysate reservoir are the same as changes in patient volume. By monitoring and controlling the level in the reservoir, forward, reverse, or zero ultrafiltration can be accomplished.

3, 4, and 8-13, where the hemodialysis system is operating with dialysate flowing in a closed loop through the sorbent filter 36, preferably the dialysate flow rate is decreased throughout treatment. More specifically, it has been discovered that more urea can be removed during a treatment using the same sorbent cartridge 36 if the duration of the treatment is increased. This is illustrated in the table below which shows that the same spKt/V can be achieved with lower dialysate flow rates as long as the treatment cycle is extended. spKt/V is a measure of adequacy for dialysis based on urea clearance over time (t) (K) and human urea volume distributed (V). The KDOQI 2015 Clinical Practice Guideline for Hemodialysis Adequacy Guideline 3.1 suggests a minimum Kt/V for thrice-weekly dialysis of 1.2. The "sp" portion of spKt/V is calculated in practice by assuming that the human body is like a single volume of fluid that uniformly retains and releases urea. It is an abbreviation for "single reservoir". This measure of dialysis effectiveness is often related to a dialysis patient's initial and final blood urea nitrogen (“BUN”), with final BUN being measured as soon as dialysis is completed. Here, the same spKt/V for treatment with a dialysate flow rate of 300 ml/min over 285 minutes can be achieved at 600 ml/min over 240 minutes, and the percent change in spKt/V is shown in bold. Measured from baseline values. However, the sorbent cartridge 36 is capable of absorbing more urea during treatments operated at lower dialysate flow rates.

In addition, for dialysate flow rates of 500-300 ml/min in a 35 L dispersed urea volume patient, spKt/V is 1.54, as seen in the table below showing a linear decrease in dialysate flow rate. It is. This is similar to 1.57 spKt/V for a constant flow rate of 400 ml/min. Similarly, for a dialysate flow rate of 550-250 ml/min in a 35 L distributed urea volume patient, spKt/V is 1.52, which is still 1 for a constant flow rate of 400 ml/min. Similar to .57spKt/V. This indicates that the average dialysate flow rate becomes more important than incremental increases in flow rate to affect urea removal.

However, again, the sorbent cartridge 36 is capable of absorbing more urea during treatments operated at reduced dialysate flow rates. Also, importantly, urea is typically released into the dialysate at higher levels at the beginning of a hemodialysis treatment compared to the end of the treatment. Therefore, higher dialysate flow rates at the beginning of treatment are preferred. To balance these opposing effects, it is desirable that patient treatment begin with dialysate flowing at a high flow rate at the beginning of treatment, but that the dialysate flow rate decreases throughout patient treatment. .

Besides optimizing urea removal within the sorbent filter, there are other reasons for changing dialysate flow rate over the course of treatment. Balancing the volume of dialysate required for the treatment with the length of the treatment can be accomplished by varying the dialysate flow rate over the course of the treatment. When urea concentrations are high at the beginning of treatment, high dialysate flow rates aid in rapidly removing urea from the blood. As the urea concentration decreases, reducing the flow rate does not unduly change the urea that can be removed from the blood, but the amount of dialysate that is wasted can be reduced.

To implement a patient treatment plan that involves decreasing the dialysate flow rate, a processor 77 is connected to the dialysate flow sensor 25 to monitor dialysate flow, and the processor 77 controls the dialysate pumps 26 and 33. is connected to the dialysate flow path to control the rate at which dialysate flows through the dialysate flow path. In addition, processor 77 includes a memory 78 that stores one or more patient treatment plans by which a patient is treated. The treatment regimen of this patent includes a desired flow rate at which the dialysate is intended to flow in different time segments throughout the patient's treatment. As illustrated in FIGS. 10-13, according to the patient treatment plan, the dialysate flow rate decreases throughout the patient's treatment. The reduction in dialysate flow rate may be gradual, as illustrated in FIG. Alternatively, the dialysate flow rate may be decreased in a linear manner, as illustrated in FIG. 12. In further alternative treatment plans, the reduction in dialysate flow rate may be exponential, inversely proportional, polynomial, or another relationship that provides a dialysate flow rate that decreases over time. For example, FIG. 12 illustrates an acceptable polynomial treatment protocol in which the rate of change of decreasing flow rate (Δ) is decreasing. Conversely, FIG. 13 illustrates an acceptable polynomial treatment protocol in which the rate of change of decreasing flow rate (Δ) is increasing.

Specifically, each patient treatment plan includes a total period "T" for treating the patient, which in turn includes multiple time periods T1, T2, T3, etc. Contains time divisions. The patient treatment plan further includes a plurality of flow rates, including at least a high flow rate operating over a time interval T1. The treatment plan further includes time periods T2, time periods T3, etc. As will be understood by those skilled in the art, if the reduction in dialysate flow rate is changed in a substantially continuous manner, such as in a linear or polynomial manner, the period per time segment may be very small. be considered.

Preferably, the dialysis treatment begins at a higher dialysate flow rate, such as 400-800 ml/min, and ends at a lower flow rate, such as 100-500 ml/min. However, the dialysis treatment may even begin at a value above 800 ml/min and end at a flow rate below 100 ml/min. More preferably, the dialysis treatment begins at a higher dialysate flow rate of 450-800 ml/min and ends at a lower flow rate of 100-450 ml/min. However, different patients may require different treatment protocols. For example, in another preferred embodiment, the patient treatment plan lasts for 4 hours, begins treatment with a dialysate flow rate of approximately 400-600 ml/min, and ends at a flow rate of 200-300 ml/min. , decreases linearly.

In the preferred embodiment illustrated in Figures 10-13, the patient treatment plan is linear over two hours, starting treatment with a dialysate flow rate of approximately 500 ml/min and ending at a flow rate of 250 ml/min. decreases to However, the treatment protocol may be different, such as linearly decreasing as illustrated in FIG. 10 or progressively decreasing as illustrated in FIG. 11. For example, for the embodiment illustrated in FIG. 11, the patient first receives a 1.0 hour time interval T1, 450-400 ml at a high dialysate flow rate of greater than 450 ml/min (illustrated at 500 ml/min). a second time period T2 of 1.0 hour at an intermediate flow rate of 350-300 ml/min (illustrated as 333 ml/min); The patient is treated for a third time segment T3 of 0.0 hours, and a final time segment T4 of 1.0 hours at a low flow rate of 300-200 ml/min (illustrated at 250 ml/min). Alternatively, to reduce the flow rate progressively or linearly, the decrease in flow rate may decrease over time (−Δ), as illustrated in FIG. , may increase over time (+Δ), as illustrated in FIG. For each of these examples illustrated in FIGS. 10-13, the dialysate flow rate starts at approximately 500 ml/min and decreases over 4 hours until ending at a flow rate of 250 ml/min. In addition to the different methods of reducing dialysate flow rate, the total treatment time T (total) of the patient treatment plan may be different for high flow rates (such as 800-400 ml/min) and low flow rates (such as 500-200 ml/min). The time period may be determined as appropriate for each patient (such as 2 to 8 hours).

To maintain proper patient treatment, the processor monitors all of the various sensors to ensure that the hemodialysis machine is operating efficiently and safely, and that any hazardous or unspecified conditions are detected. If detected, the processor corrects the defect or stops further hemodialysis treatment. For example, if the venous blood line pressure sensor 9 indicates an unsafe pressure, or if the air bubble sensor 12 detects a gaseous bubble within the venous blood line, the processor signals an alarm and the pump Once activated, the pinch valve closes and prevents further blood flow back to the patient. Similarly, if the blood leak sensor 31 detects that blood has penetrated the semi-permeable membrane of the dialyzer, the processor signals an alarm and stops further hemodialysis treatment.

The user interface of a dialysis machine includes a keyboard or A touch screen (not shown) may also be included. The processor may also include Wi-Fi or Bluetooth connectivity for communication of information or control to remote locations.

In the following, various components of the preferred hemodialysis system are identified, with numbers corresponding to the components illustrated in the figures.

Hemodialysis systems provide increased flexibility in treatment options based on the required frequency of dialysis, patient characteristics, availability of dialysate or water, and desired portability of the dialysis machine. For all treatments, the blood flow path 53 connects to the arterial blood line 1 and from the venous blood line 14 to the patient in order to convey blood from the patient to the dialyzer and back to the patient. Transports blood in a closed loop system.

Referring to FIG. 2, a first method of using a hemodialysis system does not require the use of a sorbent filter 36. Water is introduced into the machine through a fresh dialysate flow path 56 from a water supply 46, such as water supplied through reverse osmosis (RO). If required, chemical concentrates 48 and 50 are added to the clean water using chemical concentrate pumps 47 and 49. The mixed dialysate is then introduced into reservoirs 17 and 20. For this treatment, dialysate 75 from the first reservoir is recirculated past the dialyzer 8 through the bypass passageway 35 and back into the same reservoir. Once the volume of the reservoir has been recirculated, the reservoir is emptied through drain flow path 55 and the reservoir is refilled through fresh dialysate flow path 56.

Meanwhile, hemodialysis treatment continues using the second reservoir (17 or 20) while the first reservoir is emptied and refilled. As illustrated in FIG. 2, once the processor determines that all dialysate has been recirculated once, or that the dialysate has become contaminated, the processor 21, 42, 43, 51, and 52), removing the first reservoir 20 from patient treatment and inserting the second reservoir 17 into the dialysate flow path 54. Dialysate 75 from the second reservoir 17 is recirculated past the dialyzer 8 and back into the same reservoir 17 through the bypass passage 35 . This alternating switching between reservoir 17 and reservoir 20 continues until the dialysis treatment is complete. This operation is similar to, but not identical to, a traditional single-pass system since no sorbent filter is used.

In a second embodiment illustrated in FIG. 3, a sorbent cartridge 36 filters the dialysate after it passes through the dialyzer 8. To achieve this goal, the processor switches the three-way valve 34 and incorporates the sorbent cartridge 36 into the dialysate flow path 54, and the processor switches the various valve assemblies (21, 42, 43, 51 and 52). and utilize the reservoir 17 during dialysis treatment. Clean dialysate 75 is recirculated through dialyzer 8 and sorbent cartridge 36, after which the dialysate is sent back to the same reservoir 17 through dialysate flow path 54. This recirculation can be performed by the processor, including, but not limited to, when the adsorbent cartridge is used, or the dialysate fluid is contaminated, or ultrafiltration causes the reservoir 17 to become full and is being drained and refilled. To request that etc. continue as determined. On the other hand, if the fluid in the reservoir 20 becomes contaminated, it is drained through the drain channel 45 and the reservoir 20 is then refilled using the fresh dialysate channel 56.

As illustrated in FIG. 4, once the processor determines that continued use of the reservoir 17 for dialysis treatment is not appropriate, the processor determines that the various valve assemblies (21, 42, 43, 51, and 52), removing reservoir 17 from dialysate flow path 54 and instead inserting reservoir 20 into the dialysis flow path for dialysis treatment. Clean dialysate 75 is recirculated through dialyzer 8 and sorbent filter 36 back to the same reservoir 20 . Again, this recirculation continues using reservoir 20 until switching back to reservoir 17 or until the dialysis treatment is completed, as determined by the processor. While dialysis treatment continues using reservoir 20, contaminated fluid 76 within reservoir 17 is drained through the drain flow path. Reservoir 17 is then refilled using fresh dialysate flow path 56. As with other treatment methods, this alternating switching between reservoirs 17 and 20 continues until the dialysis treatment is complete.

In a further additional embodiment illustrated in FIGS. 5 and 6, a hemodialysis treatment in which a sorbent filter 36 is not utilized within the dialysate flow path 54 is performed in a manner similar to that illustrated in FIG. Although it is possible to utilize a filter 36 in the dialysate flow path 54, for this embodiment it is possible that the dialysate 75 is directed through the bypass passage 35 to avoid the sorbent filter 36. ,preferable. During treatment, dialysate 75 from the first reservoir is recirculated past the dialyzer 8 through the bypass passageway 35 and directed back to the same reservoir. Even more preferably, for this embodiment, the hemodialysis system does not include a sorbent filter 36. Instead, referring to FIGS. 5 and 6, the hemodialysis system includes a single sorbent filter 71 in a separate closed loop flow path, referred to herein as filter flow path 57. Although FIGS. 5 and 6 illustrate a hemodialysis system that includes two sorbent filters 36 and 71, the sorbent filter 36 in the dialysate flow path 54 is optional and within this embodiment of the hemodialysis system. Doesn't need to be included.

As in the previous embodiment, dialysis treatment is implemented, alternating between reservoir 17 and reservoir 20. Referring to FIG. 5, the dialysis treatment uses clean dialysate 75 in the reservoir 17, but the various valve assemblies (21, 42, 43, 51, and 52) are switched and the closed loop filter flow path 57 Insert the second reservoir 20 into the. Contaminated water 76 is drained from reservoir 20 through pump 58 and pressure sensor 59. Contaminated water 76 is then filtered through adsorbent filter 71. Reagents 61 and 65 may be introduced into the filter channels using gravity feed or pumps 62 and 66. The reagents are mixed in mixers 63 and 67 before the now cleaned dialysate is tested for suitability by conductivity testers 64 and 68, ammonium sensor 69, and pH sensor 70. If the test shows that the water is now clean, it is directed back to the reservoir 20.

Referring to FIG. 6, the processor continues to monitor the output of various sensors, including those in dialysate flow path 54. Once the water in the reservoir 17 becomes contaminated, it is removed from the dialysate flow path and the reservoir 20 is once again connected to the associated valve assemblies (21, 42, 43, 51, and 52). By toggling everything, it is replaced in its place. Dialysate 75 from second reservoir 20 is recirculated in closed loop dialysate flow path 54 past dialyzer 8 and directed back to the same reservoir. Meanwhile, the now contaminated water 76 in reservoir 17 is drained through pump 58 and pressure sensor 59 before being filtered through adsorbent filter 71 . Again, reagents 61 and 65 may be introduced into filter channel 57 and the reagents are mixed in mixers 63 and 67. The clean dialysate is now tested for suitability by conductivity testers 64 and 68, ammonium sensor 69 and pH sensor 70 before filling reservoir 17. This process of alternating reservoirs continues until the prescribed hemodialysis treatment is completed or a fault is detected that requires the treatment to be interrupted.

Like the embodiments illustrated in FIGS. 2, 3, 5, and 6, the embodiment illustrated in FIG. 7 operates in single-pass mode. Dialysate is introduced into the machine through a fresh dialysate flow path from a dialysate source 46 that flows through the dialysate flow path to the dialyzer 8 to the reservoir 17 . Thereafter, the used dialysate is then directed to a receiver for storing waste water 55 or waste liquid drainage. Although not requiring the use of a sorbent filter, this single pass mode typically requires 400-600 liters of water.

Conversely, the embodiment of the hemodialysis system illustrated in FIG. 8 operates in a closed loop recirculation mode in which dialysate flows through the sorbent filter 36. Dialysate is stored in reservoir 17 and recirculated through dialyzer 8 and sorbent cartridge 36. Chemical concentrates 48 and 50 are added to the filtered water as needed. Recirculation continues until treatment is complete, the sorbent cartridge is spent, the dialysate fluid becomes contaminated, or ultrafiltration fills the reservoir 17 and requires it to be drained and refilled. Continue as determined by the processor.

In conclusion, it should be understood that a hemodialysis system is disclosed with respect to exemplary embodiments of the invention as shown and described herein. The principles of the invention may be practiced in several configurations other than those shown and described, so that the invention is not limited in any way by the illustrative embodiments and is directed generally to hemodialysis systems. It should be understood that many forms of doing so may be taken without departing from the spirit and scope of the invention. It is also understood that the present invention is not limited to the particular geometries and materials of the disclosed constructs, but instead includes other materials now known or later developed without departing from the spirit and scope of the invention. It will be understood by those skilled in the art that functionally equivalent structures or materials may be involved. Additionally, various features of each of the embodiments described above may be combined in any logical manner and are intended to be within the scope of the invention.

Groupings of alternative embodiments, elements, or steps of the invention shall not be construed as limitations. Each group member may be referred to and claimed individually or in any combination with other group members disclosed herein. It is anticipated that one or more members of a group may be included in or deleted from a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is deemed to contain the group as modified.

Unless otherwise indicated, all numerical values expressing characteristics, items, quantities, parameters, properties, terms, etc., used in this specification and the claims, are modified in all instances by the term "about." It should be understood that As used herein, the term "about" means that the property, item, quantity, parameter, property, or term so conditioned is the property, item, quantity, parameter, property, or term so conditioned on. It is meant to include a range of ±10 percent above and below the value of the term. Therefore, unless indicated otherwise, the numerical parameters set forth herein and in the appended claims are approximations that may vary. At a minimum, and without attempting to limit the application of the Doctrine of Equivalents to the scope of this claim, each numerical indication shall be interpreted at least in light of the reported number of significant digits and by applying normal rounding techniques. should be interpreted accordingly. Notwithstanding that the numerical ranges and values describing the broad scope of the invention are approximations, the numerical ranges and values set forth in the specific examples are reported as precisely as possible. However, any numerical range or value inherently contains some error that necessarily results from the standard deviation found in those individual test measurements. The recitation of numerical ranges of values herein is only intended to serve as a shorthand way of referring individually to each separate numerical range within the range. Unless otherwise indicated herein, each individual value of a numerical range is incorporated herein as if individually recited herein.

The terms "a", "an", "the", and similar referents, used within the context of the description of the invention (particularly in the context of the following claims), are defined herein as otherwise indicated. , or unless clearly contradicted by context, should be construed as encompassing both the singular and the plural. All of the methods described herein can be performed in any suitable order, unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "etc.") provided herein is merely intended to more clearly illuminate the invention, as otherwise claimed. The invention is not intended to limit the scope of the invention. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Specific embodiments disclosed herein are further described using the phrases “consisting of” or “consisting essentially of” to refer to limitations in the claims. can be done. When used in this claim, whether filed with each revision or as an addition, the transitional term "consisting of" means that the Exclude any element, step, or component that is not included. The transitional term "consisting essentially of" limits the scope of the claim to the materials or steps defined and to those that do not substantially affect the essential and novel properties. Embodiments of the invention as so claimed are essentially or expressly described and enabled herein.

It is to be understood that the logic code, program, module, process, method, and order in which the individual elements of each method are implemented are purely exemplary. Depending on the implementation, they may be performed in any order or in parallel unless otherwise indicated in this disclosure. Further, the logic code is not related to or limited to any particular programming language, and may be implemented on one or more processors in a distributed, non-distributed, or multiprocessing environment. It can be equipped with more modules.

While several specific forms of the invention have been illustrated and described, it will be obvious that various modifications can be made without departing from the spirit and invention of the invention. Accordingly, the invention is not intended to be limited, except as by the claims below.

Claims (7)

A hemodialysis system with variable flow rate, the system comprising:
a mechanical casing;
an arterial blood line for connecting to a patient's artery for collecting blood from the patient;
a venous blood line for connecting to a patient's vein for returning blood to the patient;
A dialysis machine,
a blood flow path, the blood flow path connected to the arterial blood line and the venous blood line for conveying blood from the patient to the dialyzer and back to the patient; and,
a reservoir for storing dialysate;
a dialysate flow path, the dialysate flow path being isolated from the blood flow path and connected to the reservoir and the dialyzer for conveying dialysate from the reservoir to the dialyzer; a liquid flow path;
at least one dialysate pump for pumping dialysate through the dialysate flow path;
a blood pump for pumping blood through the blood flow path;
a dialysate flow sensor in the dialysate flow path that measures the flow rate of dialysate through the dialysate flow path;
a control processor connected to the dialysate flow sensor and the at least one dialysate pump, the control processor having a memory for storing a patient treatment plan by which a patient is to be treated; the treatment plan includes a dialysate flow rate during treatment of the patient, the dialysate flow rate being decreased over a period of time T(total) for treating the patient; Hemodialysis system with. The hemodialysis system with variable flow rate of claim 1, wherein the dialysate flow rate includes a high flow rate and a low flow rate, the low flow rate being less than 75% of the high flow rate. 2. The variable flow rate hemodialysis system of claim 1, wherein the patient treatment plan includes decreasing the dialysate flow rate in a linear manner. 2. The variable flow rate hemodialysis system of claim 1, wherein the dialysate flow rate decreases progressively and includes a high flow rate and a low flow rate. The hemodialysis system with variable flow rate according to claim 1, wherein the dialysate flow rate comprises a high flow rate of 400-800 ml/min and a low flow rate of 100-400 ml/min. The control processor causes the dialysate pump to pump 400-800 ml/min of dialysate through the dialysate flow path for at least 0.5 hours; The hemodialysis system with variable flow rate of claim 1, wherein the hemodialysis system pumps 100-400 ml/min of dialysate through the flow path for at least 0.5 hours. The hemodialysis system with variable flow rate of claim 1, further comprising a sorbent filter connected to the dialysate flow path for removing uremic toxins from the dialysate.