Blood purification device

Abstract

A blood purification device is provided that returns blood in a blood circuit to a body, wherein the blood circuit and a dialysis liquid circuit make liquid pass through each other via a blood purification membrane of a blood purifier, and includes a first flow path that makes dialysis liquid flow from the dialysis liquid circuit into the blood circuit via a connection flow path that connects the dialysis liquid circuit and the blood circuit while bypassing the blood purifier, and a second flow path that makes dialysis liquid flow from the dialysis circuit into the blood circuit via the blood purification membrane. A control device performs control to return blood in the blood circuit to the body by making dialysis liquid flow in one of the first flow path and the second flow path, determines whether a flow rate of the dialysis liquid has reached a predetermined flow rate, and performs control to return blood in the blood circuit to the body by making dialysis liquid flow in the other of the first flow path and the second flow path in response to a case where it has been determined that the flow rate of the dialysis liquid has reached the predetermined flow rate.

Description

Technical Field

[0001] This disclosure relates to blood purification devices, and more particularly to blood purification devices that return blood from a blood circuit to the body. Background Technology

[0002] If the kidneys, which are part of the body's internal organs, fail to function properly (kidney failure), their function of converting excess water into urine to excrete unwanted metabolic waste products cannot be achieved. To address kidney failure, a dialysis device is used to circulate blood from the patient outside the body, filtering metabolic waste and water through a blood purifier (hemodialysis, hereinafter referred to as dialysis treatment).

[0003] The dialysis device draws blood from the patient and guides it through a blood circuit into a blood purifier (blood flow path). Dialysate is also drawn from the dialysate supply through a dialysate circuit into the blood purifier (dialysate flow path). In the blood purifier, metabolites, electrolytes, and other components are exchanged between the blood and dialysate, purifying the blood. The purified blood is then returned to the patient. Because some blood remains in the blood circuit after dialysis treatment, this residual blood is typically returned to the patient (return blood).

[0004] As for the aforementioned methods of blood return, one known method involves introducing dialysate (or saline solution) into the blood circuit via a connecting line (replenishment line) that bypasses the blood purifier and connects the dialysate circuit and the blood circuit. The dialysate compresses the blood in the blood circuit, thereby returning the blood to the body. This method is called the first blood return step (replenishment method). On the other hand, another known method involves introducing dialysate from the dialysate circuit into the blood circuit through the filter membrane of a blood purifier. The dialysate compresses the blood in the blood circuit, thereby returning the blood to the body. This method is called the second blood return step (reverse filtration method).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: JP 2019-187789 Summary of the Invention

[0008] Patent Document 1 discloses a technique in which fluid replacement based on reverse filtration is performed simultaneously with fluid replacement using a fluid replacement line, corresponding to the permeability state of the filter membrane in a blood purifier. However, the fluid replacement procedure disclosed in Patent Document 1 is a supplementary procedure that uses a fluid replacement line in addition to reverse filtration-based fluid replacement. Therefore, it is sometimes impossible to effectively utilize the advantages of both reverse filtration-based fluid replacement and fluid replacement using a fluid replacement line.

[0009] The dialysis apparatus of the embodiment relates to a blood purification device, which includes a blood circuit and a dialysate circuit, and a control device. In the blood circuit and the dialysate circuit, liquids can flow between each other via a blood purification membrane of a blood purifier. The blood circuit and the dialysate circuit include a first flow path and a second flow path. The first flow path allows dialysate to flow from the dialysate circuit into the blood circuit via a connecting flow path. The connecting flow path bypasses the blood purifier and connects the dialysate circuit and the blood circuit. The second flow path allows the dialysate to pass through the blood purification membrane. The membrane flows from the dialysis circuit into the blood circuit, and the control device performs the following operations: controlling the flow of dialysate in one of the first flow path and the second flow path to return blood in the blood circuit to the body; determining whether the flow rate of the dialysate has reached a predetermined flow rate; and controlling the flow of dialysate in the other of the first flow path and the second flow path to return blood in the blood circuit to the body in response to the determination that the flow rate of the dialysate has reached the predetermined flow rate.

[0010] Another embodiment of the dialysis apparatus relates to a blood purification device including a blood circuit and a dialysate circuit, and a control device. In the blood circuit and the dialysate circuit, liquids can flow between each other via a blood purification membrane of a blood purifier. The blood circuit and the dialysate circuit include a first flow path and a second flow path. The first flow path allows dialysate to flow from the dialysate circuit into the blood circuit via a connecting flow path. The connecting flow path bypasses the blood purifier and connects the dialysate circuit and the blood circuit. The second flow path allows the dialysate to pass through the blood purification membrane. The membrane flows from the dialysis circuit into the blood circuit; the control device performs the following operations: controlling the flow of dialysate in one of the first and second flow paths to return blood in the blood circuit to the body; determining whether the blood return flow rate has reached a predetermined return volume; and controlling the flow of dialysate in the other of the first and second flow paths to return blood in the blood circuit to the body in response to the determination that the blood return flow rate has reached the predetermined return volume.

[0011] The blood purification device according to the embodiment can effectively leverage the advantages of both the first and second blood return steps. Attached Figure Description

[0012] Figure 1 This is an overall structural diagram of the dialysis apparatus according to the first embodiment;

[0013] Figure 2 A diagram illustrating the flow of dialysate during the first blood return step (positive direction of fluid delivery);

[0014] Figure 3 A diagram illustrating the flow of dialysate during the second blood return step (positive direction of fluid delivery);

[0015] Figure 4 A flowchart illustrating the process of the first embodiment;

[0016] Figure 5 A diagram illustrating the flow of dialysate during the second return blood step (reverse direction of fluid delivery);

[0017] Figure 6 A flowchart illustrating the process of the second embodiment;

[0018] Figure 7 This is an overall structural diagram of the dialysis apparatus according to the third embodiment;

[0019] Figure 8 A diagram illustrating the flow of dialysate during the first return blood step (reverse direction of fluid delivery);

[0020] Figure 9 A flowchart illustrating the process of the third embodiment;

[0021] Figure 10 This is an overall structural diagram of the dialysis apparatus according to the fourth embodiment;

[0022] Figure 11 A diagram illustrating the flow of dialysate during the second return blood step (reverse direction of fluid delivery);

[0023] Figure 12 A diagram illustrating the flow of dialysate during the first blood return step (positive direction of fluid delivery);

[0024] Figure 13 This is a flowchart illustrating the process of the fourth embodiment. Detailed Implementation

[0025] The dialysis apparatus (blood purification apparatus) of the embodiment will now be described with reference to the accompanying drawings. In the dialysis apparatus of the embodiment, in order to return the blood remaining in the blood circuit to the body, a first blood return step (fluid replenishment method) and a second blood return step (reverse filtration method) are alternately performed. The aforementioned step of returning the blood to the body is called the blood return step, and it is mainly performed after dialysis treatment.

[0026] In the first return blood step, dialysate flows through the dialysate circuit and then through the blood circuit. This flow of dialysate, within the blood flow path (inner side of the blood purification membrane) of the blood purifier, compresses the blood remaining in the blood circuit and the blood purifier, returning the blood to the body. Conversely, in the second return blood step, dialysate flows through the dialysate circuit and then through the blood purifier. This flow of dialysate, within the dialysate flow path (outer side of the blood purification membrane) of the blood purifier, compresses the blood through the pores of the blood purification membrane, returning the blood to the body. Furthermore, during the compression of the blood by the dialysate in both the first and second return blood steps, a portion of the two liquids are mixed.

[0027] During dialysis, blood flows through the blood flow path of the blood purifier. Due to this blood flow, proteins such as albumin in the blood can sometimes cause blockages in the pores of the blood purification membrane and part of the blood flow path. In the first return step, the dialysate flows through the blood flow path just like the blood used in dialysis. Therefore, if the blood flow path within the blood purifier is blocked, the dialysate has difficulty flowing through the blood circuit in the first return step, resulting in insufficient return. On the other hand, in the second return step, since the dialysate flows through the dialysate flow path within the blood purifier, a more complete return can be achieved compared to the first return step.

[0028] In the second return blood step, dialysate flows from the dialysate flow path to the inside of the blood purification membrane. In the second return blood step, compared to the first return blood step, the contact area between the dialysate and blood is larger, resulting in more dialysate mixing with the blood. Consequently, more dialysate is absorbed into the body in the second return blood step, which is sometimes not preferred. This means that the first return blood step can use a smaller amount of dialysate for return blood compared to the second return blood step. The dialysis apparatus of the embodiment solves the aforementioned disadvantages of the first and second return blood steps.

[0029] <First Implementation>

[0030] Figure 1This is a block diagram showing the structure of the dialysis apparatus 100 according to the first embodiment. The dialysis apparatus 100 includes, as its main components, a blood purifier 1, a blood circuit 2, a dialysate circuit 3, a refill circuit 4, a blood pump 5, a dialysate supply unit 6, a primary air inlet unit 7, a secondary air inlet unit 8, a dual-phase pump 9, a dialysate filter 10a, a dialysate filter 10b, and a control device 11. Figure 1 The components shown are merely examples of components used to implement this embodiment; in reality, chambers for capturing air bubbles of blood flowing in the blood circuit 2 are also provided.

[0031] The blood purifier 1, also known as a dialyzer, is used to purify a patient's blood. The blood purifier 1 includes a blood inlet 1a and a blood outlet 1b. The blood inlet 1a introduces blood from the blood circuit 2, and the blood outlet 1b exits the purified blood. The blood purifier 1 also includes a dialysate inlet 1c for introducing dialysate from the dialysate circuit 3, and a dialysate outlet 1d for discharging dialysate (fluid discharge). The blood purifier 1 has an internal blood purification membrane. The blood purification membrane is composed of bundles of hollow fibers (hollow fiber membranes) with pores in the sidewalls. The inner side of the blood purification membrane (hollow fibers) is the blood flow path, and the outer side of the blood purification membrane (hollow fibers) is the dialysate flow path. Blood flowing in the blood purifier 1 flows through the blood flow path, and unwanted substances such as uremic toxins are removed through the pores of the blood purification membrane via diffusion, ultrafiltration, or both. The dialysate flowing through the blood purifier 1 passes through the dialysate flow path, and only the electrolytes and other substances needed by the human body, which are present in the dialysate, pass through the pores, thereby replenishing the blood. Alternatively, the inner side of the hollow fiber can be used as the dialysate flow path, and the outer side of the hollow fiber can be used as the blood flow path.

[0032] Blood circuit 2 and dialysate circuit 3 allow fluids (blood and dialysate) to flow between each other via the blood purification membrane of blood purifier 1. Blood circuit 2 is a flow path in which blood leaving the patient is introduced into blood purifier 1, and blood exiting blood purifier 1 (purified blood) is returned to the patient (the blood is in...). Figure 1 (Flowing in the direction indicated by the arrow in blood circuit 2). Blood circuit 2 is mainly composed of a tube through which blood can pass. Blood circuit 2 includes a de-bleeding side circuit 2a and a return side circuit 2b.

[0033] The blood removal side circuit 2a is the flow path for introducing blood removed from the patient into the blood purifier 1. One end of the blood removal side circuit 2a is attached to a blood removal side puncture needle (not shown in the figure) inserted into the patient's blood vessel, and the other end is connected to the blood inlet 1a. An on / off valve (solenoid valve) V1 is configured in the blood removal side circuit 2a. The blood flow in the blood removal side circuit 2a is controlled by opening and closing the on / off valve V1. The blood return side circuit 2b is the flow path for returning blood extracted from the blood purifier 1 to the patient. One end of the blood return side circuit 2b is attached to a blood return side puncture needle (not shown in the figure) inserted into the patient's blood vessel, and the other end is connected to the blood outlet 1b. An on / off valve (solenoid valve) V2 is configured in the blood return side circuit 2b. The blood flow in the blood return side circuit is controlled by opening and closing the on / off valve V2.

[0034] Blood pump 5 is disposed in the blood loss side circuit 2a, and delivers liquid from blood circuit 2 in either the direction of travel from blood loss side circuit 2a to blood return side circuit 2b (hereinafter referred to as the forward flow direction) or the direction of travel from blood return side circuit 2b to blood loss side circuit 2a (hereinafter referred to as the reverse flow direction). Blood pump 5 is a peristaltic pump having a stator and a rotor. The forward rotation of the rotor agitates the blood loss side circuit 2a held by the stator and rotor, generating a flow in the forward flow direction. Conversely, the reverse rotation of the rotor agitates the blood loss side circuit 2a, generating a flow in the reverse flow direction. A rotary encoder (not shown in the figure) is provided in blood pump 5. The rotary encoder detects the rotational speed of the rotor.

[0035] The dialysate circuit 3 is a flow path that supplies dialysate to the blood purifier 1 and / or the blood circuit 2, and discharges the dialysate from the blood purifier 1. The dialysate circuit 3 is mainly composed of a tube through which dialysate can pass. The dialysate circuit 3 includes a dialysate inlet circuit 3a and a dialysate outlet circuit 3b.

[0036] The dialysate inlet circuit 3a is a flow path from the dialysate supply unit 6 to the dialysate inlet 1c. Dialysate flows through the dialysate inlet circuit 3a in the blood purifier 1. The dialysate inlet circuit 3a is equipped with an on / off valve (solenoid valve) V3, an on / off valve (solenoid valve) V4, and a dialysate port P. The flow of dialysate into the blood purifier 1 is controlled by opening and closing the on / off valves V3 and V4. Dialysate is dispensed from the dialysate port P.

[0037] The dialysate discharge circuit 3b is a flow path from the dialysate outlet 1d to the dialysate discharge section (not shown in the figure). Through the dialysate discharge circuit 3b, the drained fluid from the blood purifier 1 is discharged into the dialysate discharge section. An on / off valve (solenoid valve) V6 is installed in the dialysate discharge circuit 3b. The flow of drained fluid to the dialysate discharge section is controlled by opening and closing the on / off valve V6.

[0038] The rehydration circuit 4 is a connecting flow path that connects the blood circuit 2 and the dialysate circuit 3. Specifically, the rehydration circuit 4 is the flow path that supplies dialysate from the dialysate circuit 3, bypassing the blood purifier 1, to the blood circuit 2, and is the flow path from the dialysate port P to the blood loss side circuit 2a. The rehydration circuit 4 is used to return blood from the blood circuit to the patient through the first return blood step. An on / off valve (solenoid valve) V5 is configured in the rehydration circuit 4. The flow of dialysate to the blood loss side circuit 2a is controlled by opening and closing the on / off valve V5.

[0039] The dialysate supply unit 6 has a chamber for mixing pure water (RO water, etc.) and the stock solution to generate and store dialysate, and introduces the dialysate into the dialysate inlet circuit 3a. Furthermore, the dialysate supply unit 6 receives pure water from a pure water production device (RO water production device) located outside the dialysis apparatus 100 (not shown in the figure), and receives (draws in) stock solution from a stock solution tank (not shown in the figure) externally mounted on the dialysis apparatus 100. Normally, the dialysate supply unit 6 generates dialysate and introduces it into the dialysate inlet circuit 3a, but in situations such as power outages, the generation of new dialysate is sometimes limited. In such cases, the introduction of dialysate from the dialysate supply unit 6 into the dialysate inlet circuit 3a is stopped; instead, dialysate stored in the dialysate filters 10a and / or 10b is introduced into the dialysate inlet circuit 3a. Details will be described later.

[0040] The primary air inlet 7 introduces air into the dialysate circuit 3, specifically the primary dialysate filter 10a (described later). Through the primary air inlet 7, the dialysate filter 10a is open and at atmospheric pressure, causing the dialysate stored inside the filter to flow towards the dialysate port P. The primary air inlet 7 includes an on / off valve (solenoid valve) 7a, an air flow path 7b, and an air filter 7c. The on / off valve 7a, by opening, introduces air into the dialysate filter 10a via the air flow path 7b. The air filter 7c removes debris from the air.

[0041] The secondary air inlet 8 introduces air into the dialysate circuit 3, specifically the (secondary) dialysate filter 10b, described later. Through the secondary air inlet 8, the dialysate filter 10b is open and under positive pressure, causing the dialysate stored inside the filter to flow towards the dialysate port P. The secondary air inlet 8 includes a delivery pump 8a, an air flow path 8b, an on / off valve (solenoid valve) 8c, an on / off valve (solenoid valve) 8d, an air filter 8e, and an air filter 8f. The delivery pump 8a has an internal rotor, which, through rotation, introduces air into the dialysate filter 10b via the air flow path 8b. The flow of air into the dialysate filter 10b is controlled by opening and closing the on / off valves 8c and 8d, which are located between the delivery pump 8a and the dialysate filter 10b. The air filters 8e and 8f remove impurities from the air.

[0042] In addition, similar to the secondary air inlet 8, the primary air inlet 7 described above may also include a delivery pump, an air flow path, and an on / off valve.

[0043] A duplex pump 9 is configured to span both the dialysate inlet circuit 3a and the dialysate outlet circuit 3b. The duplex pump 9 introduces dialysate downstream of the dialysate inlet circuit 3a in the delivery direction, and simultaneously discharges dialysate downstream of the dialysate outlet circuit 3b in the delivery direction. Furthermore, a plunger (not shown in the figure) is installed within the housing of the duplex pump 9. The plunger is clamped and divided into a volume for the dialysate inlet circuit 3a side and a volume for the dialysate outlet circuit 3b side; the reciprocating motion of the plunger links the introduction and discharge of dialysate.

[0044] Dialysate filters 10a and / or 10b purify the dialysate by capturing substances such as endotoxins contained in the dialysate. Furthermore, in dialysate filters 10a and 10b, hollow fibers (hollow fiber membranes) with perforations formed on their sidewalls are bundled and housed within a housing. Dialysate filters 10a and / or 10b are configured to allow dialysate to flow from the primary side (inner side) to the secondary side (outer side) of the hollow fiber membrane. Dialysate filters 10a and 10b have the characteristic of preventing air passage by utilizing the surface tension of water molecules through the flow of water. Additionally, dialysate can be stored inside the housing. Alternatively, a single filter may be used instead of two separate filters (10a and 10b). Furthermore, the outer side of the hollow fiber membrane may be configured as the primary side, and the inner side as the secondary side.

[0045] The control device 11 is a processing device that controls the entire dialysis apparatus 100, including the blood pump 5 and the opening and closing valves V1 to V6. The control device 11 includes a computing unit and a storage unit (RAM and ROM, etc.). The computing unit can be installed using a processor such as a CPU or microcontroller, an ASIC (Application Specific Integrated Circuit), or an FPGA (Field Programmable Gate Array), but its form is not limited.

[0046] Next, refer to Figure 2 To ~ Figure 4 The processing of the first embodiment will be described below. In the first embodiment, an example will be described in which, in the blood return step after dialysis treatment, a second blood return step is performed after the first blood return step, thereby effectively returning the blood in the blood purifier 1 and the blood circuit 2 to the body. Furthermore, in the first embodiment, an example will be described where blood return is performed using the dialysis fluid stored in the dialysis fluid filters 10a and 10b instead of introducing new dialysis fluid from the dialysis fluid supply unit 6. The dialysis fluid in the dialysis fluid filters 10a and 10b is the dialysis fluid that has flowed through these filters and been stored during dialysis treatment. In other words, the dialysis fluid in the dialysis fluid filters 10a and 10b is clean dialysis fluid that has not been used during dialysis treatment.

[0047] Figure 2 This indicates the flow of dialysate in the first return blood step, which is the initial step in the return blood process. In the following diagrams, when the on / off valves (V1-6, 7a, 8c, and 8d) are open, the valves are shown in shaded areas; when the valves are closed, they are shown in hollow areas.

[0048] like Figure 2 As shown, in the first return blood step, on / off valves 7a, V3, V5, and V2 are opened. Additionally, blood pump 5 rotates forward. With the opening of on / off valve 7a, air is introduced into dialysate filter 10a, which is then at atmospheric pressure. Consequently, the dialysate stored in dialysate filter 10a flows in dialysate inlet circuit 3a. Through the opening of on / off valves V3, V5, and V2, and the forward rotation of blood pump 5, the dialysate flows through dialysate inlet circuit 3a, replenishment circuit 4, depletion side circuit 2a, blood purifier 1 (blood flow path), and return blood side circuit 2b. Figure 2In the diagram, a single-dotted arrow indicates the flow of the dialysate. This flow of dialysate squeezes out residual blood in the blood purifier 1 and blood circuit 2, returning it to the patient. Furthermore, during the first return blood step, a portion of the two fluids mix as the dialysate squeezes the blood.

[0049] When a predetermined amount of dialysate flows from dialysate filter 10a, the process switches from the first return blood step to the second return blood step. This switching is performed by control device 11, the details of which are described later. Figure 3 This indicates the flow of dialysate in the second blood return step.

[0050] like Figure 3 As shown, when switching from the first return blood step to the second return blood step, on / off valves 7a, V3, and V5 are closed. Additionally, blood pump 5 stops rotating. On the other hand, delivery pump 8a rotates. Furthermore, on / off valves 8c, 8d, and V4 are opened. Due to the rotation of delivery pump 8a and the opening of on / off valves 8c and 8d, air is introduced into dialysate filter 10b, creating a positive pressure in dialysate filter 10b. Consequently, the dialysate stored in dialysate filter 10b flows in dialysate inlet circuit 3a. Through the opening of on / off valve V4 and the rotation of delivery pump 8a, dialysate flows through dialysate inlet circuit 3a, blood purifier 1 (blood purification membrane), and return blood side circuit 2b. Furthermore, the dialysate flows inside blood purifier 1 in the order of dialysate flow path, blood purification membrane, and blood flow path. Figure 3 In the diagram, a single-dotted arrow indicates the flow of the dialysate. Through this flow, the dialysate squeezes the blood remaining in the blood purifier 1, returning it to the patient. Furthermore, in the second return step, during the squeezing of the blood by the dialysate, a portion of the two liquids mix. Here, the amount of dialysate and blood mixed in the second return step is greater than that in the first return step; therefore, from the viewpoint of dialysate usage, the first return step is preferred.

[0051] As described above, in the first return blood step, a smaller amount of dialysate can be used for return blood compared to the second return blood step. On the other hand, in the second return blood step, if the blood purifier 1 (blood flow path) is blocked, sufficient return blood cannot be performed (due to the blockage of the blood flow path, the fluid delivery volume per unit time is reduced). In the second return blood step, dialysate flows into the dialysate flow path, returning the blood remaining in the blood purifier 1 to the patient. In the first embodiment, the first return blood step is initially performed by allowing a certain amount of dialysate to flow in the blood circuit 2, returning the blood remaining in the blood circuit 2 and the blood purifier 1 to the body. Then, the second return blood step is performed to return the blood remaining in the blood purifier 1 to the body. Through this process, a smaller amount of dialysate can be used to return the blood remaining in the blood circuit 2 to the patient, and then the blood remaining in the blocked blood purifier 1 (blood flow path) can be returned to the patient.

[0052] Next, refer to Figure 4 The process of the first embodiment will be described below. Figure 4 The processing shown is performed according to the instructions of the control device 11. In this embodiment, a second blood return step is performed after the first blood return step. The amounts of dialysate required for the first blood return step and the amounts of dialysate required for the second blood return step are predetermined in a specified ratio. Hereinafter, the amount of dialysate required for the first blood return step is referred to as the "first dialysate volume," and the amount of dialysate required for the second blood return step is referred to as the "second dialysate volume." The first dialysate volume is a value obtained experimentally, for example, it can also be set based on the volume of the dialysate filter 10a. Similarly, the second dialysate volume is a value obtained experimentally, for example, it can also be set based on the volume of the dialysate filter 10b.

[0053] Alternatively, the amount of blood returned to the body in the first return step and the amount of blood returned to the body in the second return step can be predetermined in a specified ratio based on the pre-filled volume of the blood purifier 1 and the blood circuit 2. Hereinafter, the amount of blood returned to the body in the first return step will be referred to as the "first return amount," and the amount of blood returned to the body in the second return step will be referred to as the "second return amount." The pre-filled volume can also be predetermined for each blood purifier 1 and blood circuit 2. Furthermore, the pre-filled volume can also be measured during dialysis treatment based on the time from when blood is removed from the patient until it is returned to the patient via the blood purifier 1 and the blood circuit 2, and the amount of rotation of the blood pump 5 during that time (detected by an encoder). Alternatively, the pre-filled volume can also be measured by measuring the time from blood removal to return, triggered by the detection of blood by a blood detector or blood concentration sensor (not shown in the figure) disposed in the blood circuit 2. In addition, the blood detector is a detector that determines whether the liquid flowing in the blood circuit 2 is blood, and the blood concentration sensor is a sensor that measures the concentration of blood flowing in the blood circuit 2.

[0054] First, the control device 11 instructs the primary air inlet 7 to introduce air into the dialysate filter 10a (step S401). Following this instruction, the on / off valve 7a of the primary air inlet 7 opens, and the dialysate filter 10a is at atmospheric pressure. Thus, the dialysate stored in the dialysate filter 10a can flow in the dialysate inlet circuit 3a (more specifically, the dialysate flows by the rotation of the blood pump 5).

[0055] Next, the control device 11 instructs the opening and closing valves (opening and closing valve V3, opening and closing valve V5, and opening and closing valve V2) used for the first blood return step to open (step S402). According to this instruction, opening and closing valves V3, V5, and V2 open.

[0056] Next, the control device 11 instructs the blood pump 5 to rotate in the forward direction (step S403). Following this instruction, the blood pump 5 rotates in the forward direction. Through the processes of steps S401 to S403, the dialysate passes through the dialysate inlet circuit 3a, the replenishment circuit 4, and the blood purifier 1 (blood flow path), squeezing the blood remaining in the blood purifier 1 (blood flow path) and the blood circuit 2, returning the blood to the body (first return blood step).

[0057] Then, the control device 11 determines whether the flow rate of the dialysate flowing in the dialysate circuit 3 has reached the first dialysate volume (step S404). The process of step S404 is repeated until the flow rate of the dialysate reaches the first dialysate volume.

[0058] Furthermore, if the volume of the first dialysate exceeds the capacity of the dialysate filter 10a, dialysate stored in the dialysate filter 10b is also required for the first return blood step. In this case, it is necessary to switch from dialysate filter 10a to dialysate filter 10b to allow the dialysate to flow from dialysate filter 10b. In this embodiment, an example where the dialysate initially flows from dialysate filter 10a is described, but it is also possible to initially allow the dialysate to flow from dialysate filter 10b. In this case, sometimes the dialysate stored in dialysate filter 10a is also used, requiring a switch from dialysate filter 10b to dialysate filter 10a to allow the dialysate to flow from dialysate filter 10a.

[0059] In order to switch from dialysate filter 10a to dialysate filter 10b, the control device 11 first determines that the amount of dialysate flowing in the dialysate circuit 3 has reached a predetermined amount (e.g., the volume of the dialysate filter). Then, the control device 11 instructs the on / off valve 7a to close, and instructs the transfer pump 8a, on / off valve 8c, and on / off valve 8d to rotate and open, respectively.

[0060] On the other hand, in order to switch from dialysate filter 10b to dialysate filter 10a, the control device 11 first determines that the amount of dialysate flowing in the dialysate circuit 3 has reached a predetermined amount (e.g., the volume of the dialysate filter). Then, the control device 11 instructs the transfer pump 8a to stop rotating, instructs the on / off valves 8c and 8d to close, and instructs the on / off valve 7a to open.

[0061] The process of determining whether the flow rate of dialysate flowing in dialysate circuit 3 has reached the first dialysate volume may, for example, include detecting if the pressure between dialysate filter 10b and dialysate port P, or within blood circuit 2, is negative. This is because, based on the characteristic that dialysate filter 10a does not allow air to pass through after water is introduced, even if air is introduced into dialysate filter 10a from primary air inlet 7, if the first dialysate volume is reached, the dialysate will not flow even if the blood pump 5 is rotated (sucked), and the closed circuit will be under negative pressure. In this case, for example, a pressure gauge is installed between dialysate filter 10b and dialysate port P, or within blood circuit 2, and the pressure gauge detects the air pressure. The detected pressure value is sent to control device 11.

[0062] Furthermore, the process of determining whether the flow rate of dialysate flowing in the dialysate circuit 3 reaches the first dialysate volume may, for example, include: measuring the temperature of the air introduced from the primary air inlet 7 and the temperature of the flow path (from the primary air inlet 7 to the dialysate filter 10a) of the dialysate inlet circuit 3a, and determining whether the temperature of the dialysate inlet circuit 3a is within a specified range based on the temperature of the introduced air. This is because if a specified amount of air is introduced into the dialysate filter 10a, the temperature of the flow path is close to the temperature of the introduced air, and the specified amount of dialysate flows into the dialysate circuit 3 accordingly. In this case, for example, a thermometer is installed at the inlet of the primary air inlet 7, and the thermometer detects the temperature of the air introduced into the primary air inlet 7. Additionally, a thermometer is also installed in the flow path between the primary air inlet 7 and the dialysate filter 10a in the dialysate inlet circuit 3a, and the thermometer detects the temperature of the flow path. The detected temperature values ​​are all sent to the control device 11.

[0063] Furthermore, a flow meter can be installed in the dialysate inlet circuit 3a to determine the amount of dialysate flowing in the dialysate circuit 3. In this case, the flow meter is installed at the outlet of dialysate filter 10a or the outlet of dialysate filter 10b. When the flow meter is installed at the outlet of dialysate filter 10b, a single flow meter can be used to measure the flow rate of dialysate flowing from both dialysate filter 10a and dialysate filter 10b.

[0064] Alternatively, in step S404, the control device 11 determines whether the flow rate of blood flowing in the blood circuit 2, i.e., the return blood volume, has reached a first return blood volume. The process of determining whether the return blood volume has reached the first return blood volume may also include, for example, measuring the rotational speed of the blood pump 5, and determining whether the amount of blood flowing in the blood circuit 2 has reached a predetermined amount based on the rotational speed. Furthermore, when measuring the rotational speed of the blood pump 5, the flow rate of the dialysate flowing in the dialysate circuit 3 can also be measured.

[0065] Alternatively, the process for determining whether the returned blood volume has reached the first returned blood volume may include, for example, measuring the blood concentration within the blood circuit 2 and determining whether the blood concentration is below a predetermined value. This is because if blood remaining in the blood circuit 2 is returned, the blood concentration within the circuit decreases. In this case, a concentration meter (or colorimeter) is installed in the blood circuit 2 to detect the blood concentration. The detected concentration value is sent to the control device 11.

[0066] Return to Figure 4As explained, in step S404, when it is determined that the flow rate of the dialysate flowing in the dialysate circuit 3 has reached the first dialysate volume, the process switches from the first return blood step to the second return blood step. In step S405, the control device 11 instructs the primary air inlet 7 to stop introducing air into the dialysate filter 10a. According to this instruction, the on / off valve 7a closes. Next, the control device 11 instructs the flow of dialysate used in the first return blood step to stop (step S406). According to this instruction, the blood pump 5 stops rotating, and the on / off valves V3 and V5 close.

[0067] Next, the control device 11 instructs air to be introduced into the dialysate filter 10b relative to the secondary air inlet 8 (step S407). Upon this instruction, the delivery pump 8a of the secondary air inlet 8 rotates, and the on / off valves 8c and 8d open, placing the dialysate filter 10b under positive pressure. Next, the control device 11 instructs the on / off valve (on / off valve V4) for the second blood return step to open (step S408). According to this instruction, the on / off valve V4 opens. As a result, the dialysate stored in the dialysate filter 10b flows in the dialysate inlet circuit 3a.

[0068] Through steps S405 to S408, dialysate flows from dialysate inlet circuit 3a into blood purifier 1 (blood purification membrane). The dialysate squeezes the blood remaining in blood purifier 1 (blood purification membrane) to the return blood side circuit 2b, returning the blood to the body (second return blood step). Furthermore, inside blood purifier 1, dialysate flows in the order of dialysate flow path, blood purification membrane, and blood flow path. After step S408, if control device 11 determines that the flow rate of dialysate flowing in dialysate circuit 3 has reached the second dialysate volume (or the return blood volume in blood circuit 2 has reached the second return blood volume) (step S409), it instructs the transfer pump 8a to stop rotating, thus ending the operation of dialysis apparatus 100. The determination of dialysate flow rate or return blood volume in step S409 is the same as the determination method described in step S404, therefore, the description is omitted.

[0069] As described above, the first embodiment has been explained. In the first embodiment, firstly, through a first return blood step, the blood remaining in the blood circuit 2 and the blood purifier 1 (the unblocked blood flow path) is returned to the body. Then, through a second return blood step, the blood remaining in the blood purifier 1 is returned to the body. According to the first embodiment, compared to the case where blood is returned only through the second return blood step without the first return blood step, less dialysate can be used to recover the blood remaining in the blood circuit 2. In addition, compared to the case where blood is returned only through the first return blood step without the second return blood step, the blood remaining in the blocked blood purifier 1 can be recovered.

[0070] In the first embodiment, an example of using dialysate stored in dialysate filters 10a and 10b for blood return was described. For example, in the event of a power outage in the environment where the dialysis apparatus 100 is installed, the dialysis apparatus 100 continues to function minimally using its built-in battery (not shown in the figure). However, in a system structure that operates in cooperation with an external device (such as a pure water production device), if the external device does not have a battery, or if even the built-in battery of the dialysis apparatus 100 cannot provide sufficient power, the generation of new dialysate may be limited (sometimes the dialysate supply unit 6 cannot generate dialysate normally). In this embodiment, in the event of a power outage during dialysis treatment, instead of dialysate from the dialysate supply unit 6, air from the primary air inlet unit 7 and the secondary air inlet unit 8 is introduced into the dialysate circuit 3, thereby enabling blood return using the dialysate stored in dialysate filters 10a and 10b.

[0071] Furthermore, in the first embodiment, the dialysate stored in dialysate filter 10a is used for the first return blood step, and the dialysate stored in dialysate filter 10b is used for the second return blood step. However, any amount of dialysate from any filter can also be used for the respective return blood steps. Switching from dialysate filter 10a to dialysate filter 10b can also be performed as needed.

[0072] <Second Implementation Method>

[0073] Next, refer to Figure 5 and Figure 6 The second embodiment will now be described. In the first embodiment, in the second blood return step performed after the first blood return step, blood is squeezed from the dialysate circuit 3 through the dialysate of the blood purifier 1, and the blood is returned to the patient's body. That is, the second blood return step is performed in the direction from the blood loss side circuit 2a to the blood return side circuit 2b (the forward direction of fluid delivery). In the second embodiment, in addition to the process described in the first embodiment, after the second blood return step in the forward direction of fluid delivery, a second blood return step is performed in the direction from the blood return side circuit 2b to the blood loss side circuit 2a (the reverse direction of fluid delivery).

[0074] Figure 5 This indicates the flow of dialysate in the second return blood step in the reverse direction, which occurs after the second return blood step in the forward direction of dialysate delivery.

[0075] like Figure 5As shown, when switching from the second return blood step in the forward direction of fluid delivery to the second return blood step in the reverse direction of fluid delivery, the on / off valves 8c, 8d, and V2 are closed. Additionally, the delivery pump 8a stops rotating. On the other hand, the on / off valves 7a, V3, and V1 are opened. Furthermore, the blood pump 5 rotates in the reverse direction. With the opening of the on / off valve 7a, air is introduced into the dialysate filter 10a, bringing the dialysate filter 10a to atmospheric pressure. Consequently, the dialysate stored in the dialysate filter 10a flows in the dialysate inlet circuit 3a. Through the opening of the on / off valves V3 and V1, and the reverse rotation of the blood pump 5, the dialysate flows through the dialysate inlet circuit 3a, the blood purifier 1 (blood purification membrane), and the desiccation side circuit 2a. Furthermore, inside the blood purifier 1, the dialysate flows in the order of dialysate flow path, blood purification membrane, and blood flow path. Figure 5 In the diagram, a single-dot dashed arrow indicates the flow of the dialysate. Through this flow, the dialysate from the dialysate circuit 3 through the blood purifier 1 squeezes the blood downstream in the delivery direction, returning the blood to the patient's body.

[0076] In the first blood return step and the second blood return step in the forward direction of fluid delivery, the dialysate does not flow in the depletion side circuit 2a (specifically, the region from the connection point of the replenishment circuit 4 to the front end of the depletion side circuit 2a). Therefore, the blood remaining in the depletion side circuit 2a cannot be adequately returned to the body. In the second embodiment, after the second blood return step in the forward direction of fluid delivery, a second blood return step in the reverse direction of fluid delivery is performed, thus enabling the blood remaining in the depletion side circuit 2a to be returned to the body.

[0077] Next, refer to Figure 6 The processing of the second embodiment will be described below. In this embodiment, after the first blood return step and the second blood return step in the forward direction of fluid delivery, a second blood return step in the reverse direction of fluid delivery is performed. The amount of dialysate required for the first blood return step (first dialysate volume), the amount of dialysate required for the second blood return step in the forward direction of fluid delivery (second dialysate volume), and the amount of dialysate required for the second blood return step in the reverse direction of fluid delivery are predetermined in a specified ratio. Hereinafter, the amount of dialysate required for the second blood return step in the reverse direction of fluid delivery will be referred to as the "third dialysate volume".

[0078] Alternatively, for example, the amount of blood returned to the body in the first return step (first return amount), the amount of blood returned to the body in the second return step in the forward direction of fluid delivery (second return amount), and the amount of blood returned to the body in the second return step in the reverse direction of fluid delivery can be predetermined according to the pre-filled volume of the blood purifier 1 and the blood circuit 2, at a specified ratio. Hereinafter, the amount of blood returned to the body in the second return step in the reverse direction of fluid delivery will be referred to as the "third return amount".

[0079] Figure 6 The process shown is in Figure 4 This is a process that adds new processing based on the existing processing. Therefore, Figure 6 The processing of steps S601 to S609 shown is... Figure 4 The processes in steps S401 to S409 are the same, so the explanation is omitted. In step S609, when it is determined that the flow rate of the dialysate flowing in the dialysate circuit 3 has reached the second dialysate volume, the process switches from the second blood return step in the forward direction of dialysate delivery to the second blood return step in the reverse direction of dialysate delivery.

[0080] In the second embodiment, the dialysate stored in dialysate filter 10a is used for the first return blood step and the second return blood step in the forward direction of blood delivery, and the dialysate stored in dialysate filter 10b is used for the second return blood step in the reverse direction of blood delivery. However, the amount of dialysate used in each step of the first return blood step, the second return blood step in the forward direction of blood delivery, and the return blood step in the reverse direction of blood delivery can be arbitrarily set according to the amount of dialysate stored in dialysate filters 10a and 10b. Switching from dialysate filter 10a to dialysate filter 10b (or from dialysate filter 10b to dialysate filter 10a) can also be performed as needed.

[0081] In step S610, control device 11 instructs the secondary air inlet 8 to stop introducing air into the dialysate filter 10b. According to this instruction, the delivery pump 8a of the secondary air inlet 8 stops rotating, and the on / off valves 8c and 8d close. Next, control device 11 instructs the cessation of dialysate flow for the second return blood step in the forward direction of fluid delivery (step S611). According to this instruction, the on / off valve V2 closes.

[0082] Next, the control device 11 instructs the primary air inlet 7 to introduce air into the dialysate filter 10a (step S612). According to this instruction, the on / off valve 7a of the primary air inlet 7 opens, and the dialysate filter 10a is at atmospheric pressure.

[0083] Next, the control device 11 instructs the on / off valves (on / off valve V3 and on / off valve V1) used for the second blood return step in the reverse direction of fluid delivery to open (step S613). According to this instruction, on / off valves V3 and V1 open. Then, the control device 11 instructs the blood pump 5 to rotate in the reverse direction (step S614). According to this instruction, the blood pump 5 rotates in the reverse direction. As a result, the dialysate stored in the dialysate filter 10a flows in the dialysate inlet circuit 3a.

[0084] Through steps S609 to S614, the dialysate flows from the dialysate inlet circuit 3a through the blood purifier 1 (blood purification membrane). The dialysate squeezes the blood remaining in the blood purifier 1 (blood purification membrane) downstream in the delivery direction, returning the blood to the patient's body (the second return blood step in the reverse direction of delivery). Furthermore, inside the blood purifier 1, the dialysate flows in the order of dialysate flow path, blood purification membrane, and blood flow path. After step S614, if the control device 11 determines that the flow rate of the dialysate flowing in the dialysate circuit 3 has reached the third dialysate volume (or the return blood volume in the blood circuit 2 has reached the third return blood volume) (step S615), it instructs the blood pump 5 to stop rotating, thus ending the operation of the dialysis apparatus 100. The determination of the dialysate flow rate or return blood volume in step S615 is the same as the determination method described in step S404 of the first embodiment, therefore, the description is omitted.

[0085] As described above, the second embodiment has been explained. In the second embodiment, initially, through the first return blood step, the blood remaining in the blood circuit 2 is returned to the body. Through the second return blood step in the forward direction of fluid delivery, the blood remaining in the blood purifier 1 and the blood circuit 2 is returned from the front end of the return blood side circuit 2b to the patient's body. Through the second return blood step in the reverse direction of fluid delivery, the blood remaining in the blood purifier 1 and the blood circuit 2 is returned from the debled blood side circuit 2a to the patient's body. According to the second embodiment, the blood remaining in the debled blood side circuit 2a can also be fully recovered.

[0086] Furthermore, in the second embodiment, the second blood return step in the reverse direction of fluid delivery is performed after the second blood return step in the forward direction of fluid delivery, but the order can also be reversed. That is, the second blood return step in the forward direction of fluid delivery can also be performed after the first blood return step and the second blood return step in the reverse direction of fluid delivery.

[0087] <Third Implementation Method>

[0088] Next, refer to Figures 7 to 9 The third embodiment will now be described. In the first embodiment, during the initial first return blood step, dialysate flows from the dialysate circuit 3 through the blood loss side replenishment circuit 4a and the blood loss side circuit 2a, while blood returns to the body from the return blood side circuit 2b. That is, a first return blood step is performed in the direction from the blood loss side circuit 2a to the return blood side circuit 2b (the forward direction of fluid delivery). In the third embodiment, in addition to the process described in the first embodiment, after the first return blood step in the forward direction of fluid delivery, a first return blood step is performed in the direction from the return blood side circuit 2b to the blood loss side circuit 2a (the first return blood step in the reverse direction of fluid delivery). Furthermore, after the first return blood step in the reverse direction of fluid delivery, a second return blood step is performed (the second return blood step in the forward direction of fluid delivery).

[0089] Figure 7 This is an overall structural diagram illustrating the structure of the dialysis apparatus 200 according to the third embodiment. In the dialysis apparatus 200, the replenishment circuit 4 differs from that of the dialysis apparatus 100 in the first and second embodiments. The replenishment circuit 4 of the dialysis apparatus 100 is a flow path from the dialysate port P to the blood loss side circuit 2a, but the replenishment circuit 4 of the dialysis apparatus 200 includes a blood loss side replenishment circuit 4a and a blood return side replenishment circuit 4b. The blood loss side replenishment circuit 4a corresponds to the replenishment circuit 4 of the dialysis apparatus 100.

[0090] The refill circuit 4b on the blood return side is used to return blood from the blood circuit to the patient via the first refill step in the reverse direction of fluid delivery, from the dialysate port P to the refill circuit 2b. An on / off valve (solenoid valve) V7 is installed in the refill circuit 4b. The flow of dialysate to the refill circuit 2b is controlled by opening and closing the valve V7.

[0091] Figure 8 This indicates the flow of dialysate in the first return blood step in the reverse direction of the dialysate delivery process, which occurs after the first return blood step in the forward direction of dialysate delivery.

[0092] like Figure 8 As shown, when switching from the first return blood step in the forward direction of fluid delivery to the first return blood step in the reverse direction of fluid delivery, the on / off valve V5 closes. On the other hand, the blood pump 5 rotates in the reverse direction, and the on / off valve V7 opens. Through the opening of the on / off valve V7 and the reverse rotation of the blood pump 5, dialysate flows through the dialysate inlet circuit 3a, the return blood side replenishment circuit 4b, the return blood side circuit 2b, the blood purifier 1 (blood flow path), and the desiccation side circuit 2a. Figure 8 In the diagram, a single-dot dashed arrow indicates the flow of the dialysate. This flow of dialysate squeezes out the blood remaining in the blood purifier 1 (blood flow path) and blood circuit 2, returning the blood from the arteries back into the body.

[0093] In the first return blood step in the forward direction of fluid delivery, the dialysate does not flow in the debledation side circuit 2a. Therefore, the blood remaining in the debledation side circuit 2a cannot be adequately returned to the body. In the third embodiment, after the first return blood step in the forward direction of fluid delivery, a first return blood step in the reverse direction of fluid delivery is performed, thus enabling the blood remaining in the debledation side circuit 2a to be returned to the body.

[0094] Next, refer to Figure 9The processing of the third embodiment will be described below. In this embodiment, after the first blood return step in the forward direction of fluid delivery, a first blood return step in the reverse direction of fluid delivery and a second blood return step in the forward direction of fluid delivery are performed. The amount of dialysate required for the first blood return step in the forward direction of fluid delivery (first dialysate volume), the amount of dialysate required for the second blood return step (forward direction of fluid delivery) (second dialysate volume), and the amount of dialysate required for the first blood return step in the reverse direction of fluid delivery are predetermined in a predetermined ratio. Hereinafter, the amount of dialysate required for the first blood return step in the reverse direction of fluid delivery will be referred to as the "fourth dialysate volume".

[0095] Alternatively, for example, the amount of blood returned to the body in the first return blood step in the forward direction of fluid delivery (first return blood amount), the amount of blood returned to the body in the second return blood step (forward direction of fluid delivery) (second return blood amount), and the amount of blood returned to the body in the first return blood step in the reverse direction of fluid delivery can be predetermined according to the pre-filled volume of the blood purifier 1 and the blood circuit 2, at a predetermined ratio. Hereinafter, the amount of blood returned to the body in the first return blood step in the reverse direction of fluid delivery will be designated as the "fourth return blood amount".

[0096] Figure 9 The process shown is in Figure 4 The resulting process is obtained by adding new processing steps to the existing processing. Therefore, Figure 9 The processing of steps S901 to S904 shown is... Figure 4 The processes in steps S401 to S404 are the same, so their descriptions are omitted. Furthermore, since the processes in steps S909 to S913 are the same... Figure 4 The processes in steps S405 to S409 are the same, so their description is omitted. In step S904, when it is determined that the flow rate of the dialysate flowing in the dialysate circuit 3 has reached the first dialysate volume, the process switches from the first blood return step in the forward direction of dialysate delivery to the first blood return step in the reverse direction of dialysate delivery.

[0097] In the third embodiment, the dialysate stored in dialysate filter 10a is used in the first return blood step in the forward direction of fluid delivery and the first return blood step in the reverse direction of fluid delivery, and the dialysate stored in dialysate filter 10b is used in the second return blood step. However, the amount of dialysate used in each step of the first return blood step in the forward direction of fluid delivery, the first return blood step in the reverse direction of fluid delivery, and the second return blood step in the forward direction of fluid delivery can be arbitrarily set according to the amount of dialysate stored in dialysate filters 10a and 10b. Switching from dialysate filter 10a to dialysate filter 10b (or from dialysate filter 10b to dialysate filter 10a) can also be performed as needed.

[0098] In step S905, control device 11 instructs the flow of dialysate for the first return blood step in the positive direction of fluid delivery to be stopped. According to this instruction, the on / off valve V5 closes.

[0099] Next, the control device 11 instructs the opening and closing valves (opening and closing valves V1 and V7) for the first blood return step in the reverse direction of fluid delivery to open (step S906). According to this instruction, opening and closing valves V1 and V7 open. Then, the control device 11 instructs the blood pump 5 to rotate in the reverse direction (step S907). According to this instruction, the blood pump 5 rotates in the reverse direction.

[0100] Through steps S905 to S907, dialysate flows from dialysate inlet circuit 3a into the return blood side replenishment circuit 4b and return blood side circuit 2b, squeezing the blood remaining in the blood purifier 1 and the blood removal side circuit 2a, returning the blood from the artery back into the body (first return blood step in the reverse direction of fluid delivery). Afterwards, when the control device 11 determines that the flow rate of dialysate flowing in dialysate circuit 3 has reached the fourth dialysate volume (or the return blood volume in blood circuit 2 has reached the fourth return blood volume) (step S908), it switches from the first return blood step in the reverse direction of fluid delivery to the second return blood step. The determination of the dialysate flow rate or return blood volume in step S908 is the same as the determination method described in step S404 of the first embodiment, therefore, the description is omitted.

[0101] As described above, the third embodiment has been explained. In the third embodiment, firstly, through a first backflow step in the forward direction of fluid delivery, the blood remaining in the blood circuit 2 is returned to the patient's body from the front end of the backflow side circuit 2b. Then, through a first backflow step in the reverse direction of fluid delivery, the blood remaining in the blood circuit 2 is returned to the patient's body from the front end of the debledation side circuit 2a. According to the third embodiment, the blood remaining in the debledation side circuit 2a can also be fully recovered.

[0102] Furthermore, in the third embodiment, the first blood return step in the forward direction of fluid delivery is performed after the first blood return step in the reverse direction of fluid delivery, but the order can also be reversed. That is, the first blood return step and the second blood return step in the forward direction of fluid delivery can also be performed after the first blood return step in the reverse direction of fluid delivery.

[0103] <Fourth Implementation>

[0104] Next, refer to Figures 10 to 13The fourth embodiment will now be described. In the first to third embodiments, examples were given where the treatment performed before the blood return step was limited to hemodialysis. In the fourth embodiment, the treatment performed before the blood return step includes not only hemodialysis but also hemofiltration and hemodiafiltration. Specifically, in the fourth embodiment, based on the type of treatment (treatment mode) performed on the patient, the blood return step is performed by selecting either the first or second blood return step after that treatment. Furthermore, in this embodiment, hemodialysis, hemofiltration, and hemodiafiltration are abbreviated as HD treatment, HF treatment, and HDF treatment, respectively.

[0105] Unlike hemodialysis (HD) treatment, HF therapy uses a blood purifier as described above to filter water, metabolites, and electrolytes from the blood, removing them as filtrate. Instead of the removed filtrate, dialysate is introduced as a replenishing fluid into the dialysate circuit and injected into the body through the blood circuit. Compared to HD treatment, HF therapy is superior in removing unwanted substances from the body.

[0106] In HDF treatment, the dialysis fluid used in HD treatment is introduced simultaneously with the blood filtration and rehydration fluid infusion performed in HF treatment. Compared to HD treatment, HDF treatment is superior at removing large molecular weight substances from the blood, while compared to HF treatment, it is superior at removing small molecular weight substances. HDF and HF treatments differ in that HDF treatment uses a pre-dilution method where the rehydration fluid is injected upstream of the blood purifier, while HF treatment uses a post-dilution method where the rehydration fluid is injected downstream of the blood purifier.

[0107] In post-dilution HF and HDF treatments, the blood is diluted by injecting supplemental fluid; however, because dilution occurs after the blood has passed through a blood purifier, the blood within the purifier is in a concentrated state. Figures 10 to 12 In the example shown, a second blood return step (reverse flow) is performed to dilute the concentrated blood, followed by a first blood return step (forward flow). These steps are performed, for example, in the event of a power outage during HF or HDF treatment.

[0108] Figure 10This is an overall structural diagram illustrating the structure of the dialysis apparatus 300 according to the fourth embodiment. Similar to the dialysis apparatus 200 of the third embodiment, the replenishment circuit 4 in the dialysis apparatus 300 includes a blood loss side replenishment circuit 4a and a blood return side replenishment circuit 4b. The blood loss side replenishment circuit 4a corresponds to the blood loss side replenishment circuit 4a of the dialysis apparatus 200. A replenishment pump 12 is disposed in the blood return side replenishment circuit 4b. The replenishment pump 12 delivers fluid in the direction of travel from the blood return side replenishment circuit 4b to the blood return side circuit 2b. The replenishment pump 12 is a peristaltic pump having a stator and a rotor. By rotating the rotor in the forward direction, it agitates the blood return side replenishment circuit 4b held by the stator and rotor, generating a flow towards the blood return side circuit 2b. The flow of dialysate to the blood return side circuit 2b is controlled by driving the replenishment pump 12.

[0109] Although not shown in the diagram, in post-dilution HF and HDF treatments, dialysate from the dialysate supply unit 6 is introduced into the dialysate inlet circuit 3a, and from the dialysate port P, it is injected as replenishment fluid into the return blood side circuit 2b via the return blood side replenishment circuit 4b. The injected replenishment fluid is used to dilute the blood filtered by the blood purifier 1.

[0110] Figure 11 This refers to the flow of dialysate in the second return blood step, which is the reverse direction of the initial fluid delivery, following HF or HDF treatment.

[0111] like Figure 11 As shown, in the second blood return step, on / off valves 7a, V3, V4, and V1 are opened. Additionally, blood pump 5 rotates in the reverse direction. With the opening of on / off valve 7a, air is introduced into dialysate filter 10a, which is then at atmospheric pressure. Consequently, the dialysate stored in dialysate filter 10a flows in dialysate inlet circuit 3a. Through the opening of on / off valves V3, V4, and V1, and the reverse rotation of blood pump 5, the dialysate flows through dialysate inlet circuit 3a, blood purifier 1 (blood purification membrane), and desiccation side circuit 2a. Furthermore, inside blood purifier 1, the dialysate flows in the order of dialysate flow path, blood purification membrane, and blood flow path. Figure 11 In the diagram, a single-dot dashed arrow indicates the flow of the dialysate. Through this flow of dialysate, the blood from the dialysate circuit 3 is squeezed upstream in the delivery direction by the dialysate in the blood purifier 1, returning the blood to the patient's body.

[0112] When a specified amount of dialysate flows from dialysate filter 10a, the process switches from the second return blood step to the first return blood step. Figure 12 This indicates the flow of dialysate in the first return blood step, which is performed in the positive direction of fluid delivery after the second return blood step.

[0113] like Figure 12 As shown, when switching from the second return blood step to the first return blood step in the forward direction of fluid delivery, the on / off valves 7a, V3, V4, and V1 are closed. Meanwhile, the delivery pump 8a rotates, and the blood pump 5 rotates forward. Additionally, the on / off valves 8c, 8d, V5, and V2 are opened. Due to the rotation of the delivery pump 8a and the opening of the on / off valves 8c and 8d, air is introduced into the dialysate filter 10b, creating a positive pressure in the dialysate filter 10b. Consequently, the dialysate stored in the dialysate filter 10b flows in the dialysate inlet circuit 3a. Through the opening of the on / off valves V5 and V2, and the forward rotation of the blood pump 5, the dialysate flows through the dialysate inlet circuit 3a, the blood loss side replenishment circuit 4a, the blood loss side circuit 2a, the blood purifier 1, and the return blood side circuit 2b. Figure 12 In the diagram, a single-dot dashed arrow indicates the flow of the dialysate. This flow of dialysate squeezes out residual blood in the blood purifier 1 (blood flow path) and blood circuit 2, returning the blood from the arteries back into the body.

[0114] As described above, during HF and HDF treatments (in the post-dilution mode), the blood within the blood purifier 1 is in a concentrated state. Therefore, by performing a second backflow step in the reverse direction after HF and HDF treatments, the dialysate flows through the blood purification membrane of the blood purifier 1, diluting the blood within the blood purifier 1 and eliminating the concentrated state of the blood. Furthermore, through this second backflow step in the reverse direction, the dialysate passes through the blood pump 5; therefore, by controlling the rotation of the blood pump, the flow rate of the dialysate used for dilution can be easily controlled.

[0115] Next, refer to Figure 13 The processing of the fourth embodiment will be described below. In this embodiment, based on the type of treatment (treatment mode) performed on the patient, either the first blood return step or the second blood return step is performed, and then the other of the first blood return step and the second blood return step is performed. Furthermore, in Figure 13 In the example shown, during treatment of a patient, a power outage occurs in the environment where the dialysis apparatus 300 is installed, and a blood return step is performed using dialysate stored in dialysate filters 10a and 10b. The amount of dialysate required for the initial blood return step (first dialysate volume) and the amount of dialysate required for subsequent blood return steps (second dialysate volume) are predetermined in a predetermined ratio.

[0116] The control device stores a mapping table in a storage device (not shown in the figure) that establishes a correspondence between values ​​representing treatment modes and post-treatment blood return steps. For example, the mapping table includes data representing the following correspondences.

[0117] [Table 1]

[0118] Treatment mode Step 1 for getting a refund (previous step) Step 2 for getting a refund (in later steps) HD treatment First step in blood return (fluid delivery in the correct direction) Second blood return step (fluid delivery in the positive direction) HF treatment The second blood return step (intra-directional fluid delivery) First step in blood return (fluid delivery in the correct direction) HDF treatment The second blood return step (intra-directional fluid delivery) First step in blood return (fluid delivery in the correct direction)

[0119] The mapping table shown in Table 1 can also be pre-stored in a storage device. In this case, the treatment mode is manually selected at the start of treatment, and the corresponding value is stored in the storage device. Alternatively, the treatment mode and blood return step can be manually selected at the start of treatment, and the corresponding values ​​are stored in the storage device.

[0120] In step S1301, in response to a power outage in the environment where the dialysis device 300 is installed, the control device 11 determines the treatment mode corresponding to the treatment being performed on the patient at that time. In this embodiment, HF treatment or HDF treatment is performed.

[0121] Next, the control device 11 refers to the mapping table shown in Table 1 and, based on the treatment mode determined in step S1301, selects either the first blood return step or the second blood return step as the initial blood return step (preceding step) (step S1302). In this embodiment, corresponding to HF treatment or HDF treatment, the second blood return step (reverse direction of fluid delivery) is performed first. Alternatively, the second blood return step can also be a blood return step in the forward direction of fluid delivery.

[0122] Next, the control device 11 instructs air to be introduced into the dialysate filter 10a relative to the primary air inlet 7 (step S1303). According to this instruction, the on / off valve 7a of the primary air inlet 7 opens, and the dialysate filter 10a is at atmospheric pressure.

[0123] Next, the control device 11 instructs the on / off valve V3 and blood pump 5 to perform the preceding steps (step S1304). In this embodiment, since the second blood return step in the reverse direction of fluid delivery is performed first, the control device 11 instructs the on / off valves (on / off valve V3, on / off valve V4, and on / off valve V1) used for the second blood return step to open. According to this instruction, on / off valves V3, V4, and V1 open. Furthermore, the control device 11 instructs the blood pump 5 to rotate in the reverse direction. According to this instruction, the blood pump 5 rotates in the reverse direction. As a result, the dialysate stored in the dialysate filter 10a flows in the dialysate inlet circuit 3a.

[0124] Through the processes of steps S1303 and S1304, the dialysate flows from the dialysate inlet circuit 3a into the blood purifier 1 (blood purification membrane). The dialysate squeezes the blood remaining in the blood purifier 1 (blood purification membrane) to the blood removal side circuit 2a, returning the blood to the body (second blood return step).

[0125] Next, the control device 11 determines that the flow rate of the dialysate flowing in the dialysate circuit 3 has reached the first dialysate volume (or the amount of blood returned in the blood circuit 2 has reached the first blood returned volume) (step S1305). The determination of the dialysate flow rate or the amount of blood returned in step S1305 is the same as the determination method described in the first embodiment, so its description is omitted. If it is determined that the dialysate flow rate has reached the first dialysate volume, the control device 11 instructs to stop the introduction of air into the dialysate filter 10a relative to the primary air inlet 7 (step S1306). According to this instruction, the on / off valve 7a closes. Then, the control device 11 instructs to stop the flow of dialysate used in the previous step (step S1307). According to this instruction, the blood pump 5 stops rotating, and the on / off valves V3, V4, and V1 close.

[0126] Next, the control device 11 refers to the mapping table shown in Table 1 and, based on the treatment mode determined in step S1301, selects the other of the first and second blood return steps as the blood return step performed after the earlier step (the later step) (step S1308). In this embodiment, the first blood return step (in the forward direction of fluid delivery) corresponding to HF treatment or HDF treatment is performed as the later step. Furthermore, the first blood return step can also be a blood return step in the reverse direction of fluid delivery.

[0127] Next, the control device 11 instructs air to be introduced into the dialysate filter 10b relative to the secondary air inlet 8 (step S1309). According to this instruction, the delivery pump 8a of the secondary air inlet 8 rotates, the on / off valves 8c and 8d open, and the dialysate filter 10b is under positive pressure.

[0128] Then, the control device 11 instructs the on / off valve V5 and the blood pump 5 to proceed with subsequent steps (step S1310). In this embodiment, since the first blood return step in the forward direction of fluid delivery is performed as a subsequent step, the control device 11 instructs the on / off valves (on / off valve V5 and on / off valve V2) used for the first blood return step to open. According to this instruction, on / off valves V5 and V2 open. Additionally, the control device 11 instructs the blood pump 5 to rotate forward relative to it. According to this instruction, the blood pump 5 rotates forward. As a result, the dialysate stored in the dialysate filter 10b flows in the dialysate inlet circuit 3a.

[0129] Through steps S1309 and S1310, dialysate flows from dialysate inlet circuit 3a into replenishment circuit 4a and blood loss circuit 2a on the blood loss side, squeezing the blood remaining in blood purifier 1 and return circuit 2b, returning the blood from the veins back into the body (first return step in the forward direction of fluid delivery). After step S1310, if the control device 11 has determined that the flow rate of dialysate flowing in dialysate circuit 3 has reached the second dialysate volume (or the return blood volume in blood circuit 2 has reached the second return blood volume) (step S1311), it instructs the delivery pump 8a to stop rotating, etc., thus ending the operation of the dialysis apparatus 300. The determination of the dialysate flow rate or return blood volume in step S1311 is the same as the determination method described in the first embodiment, therefore its description is omitted.

[0130] As described above, the fourth embodiment has been explained. In the fourth embodiment, based on the treatment mode corresponding to the treatment performed on the patient, either the first blood return step or the second step is selected as the preceding step. As described above, in HF treatment and HDF treatment, the blood in the blood purifier 1 is in a concentrated state. Therefore, when the treatment performed on the patient is HF treatment or HDF treatment, by initially performing the second blood return step, the blood in the blood purifier 1 can be diluted, and the diluted blood can be returned to the body.

[0131] Furthermore, as described above, the first blood return step is performed initially, followed by the second blood return step. This allows for the use of less dialysate to recover blood remaining in blood circuit 2. During HD treatment, the blood concentration problem described above does not occur. Therefore, when treating a patient with HD, the aforementioned advantages can be achieved by performing blood return in the order of the first and second blood return steps.

[0132] Furthermore, the blood return steps shown in Table 1 are merely illustrative, and the first and second blood return steps can be performed in the optimal order based on the treatment mode corresponding to the treatment performed on the patient. Also, as explained in embodiments 1 to 3, in each of the first and second blood return steps, the blood return step using either the forward or reverse flow of fluid delivery can be associated with the treatment mode. Additionally, HDF treatment can also correspond to blood return steps in both pre-dilution and post-dilution methods.

[0133] <Other Implementation Methods>

[0134] In addition to the embodiments 1 to 4 described above, blood return can also be performed in the order shown in the following table, for example. In the fourth embodiment, the blood return steps in the order shown in Table 2 correspond to the treatment mode. In any of these methods, the amount of dialysate required for each blood return is predetermined in a prescribed ratio (or, the amount of blood returned to the body in each blood return is predetermined in a prescribed ratio). It should be noted that the combinations of blood return directions shown in the table are merely illustrative, and the blood return methods can be combined in any order without departing from the concept of the invention.

[0135] [Table 2]

[0136]

[0137]

[0138] In the first to fourth embodiments described above, the dialysate stored in the dialysate filters 10a and 10b is introduced into the dialysate inlet circuit 3a. However, this method is not limited to this; the dialysate generated by the dialysate supply unit 6 can also be introduced into the dialysate inlet circuit 3a. In this case, the control device 11 controls the flow of the dialysate by controlling the drive of the duplex pump 9. In the above-described process of determining whether the dialysate has reached the first dialysate volume, the flow rate of the dialysate flowing in the dialysate circuit 3 can also be determined based on the drive amount of the duplex pump 9 (the rotation amount of the motor that serves as the drive source).

[0139] Furthermore, the first to fourth embodiments described above are primarily applied to the blood return step, but are not limited to such examples. The aforementioned treatment can also be applied to fluid resuscitation steps, which are used to prevent a drop in blood pressure caused by a reduction in the patient's blood volume due to a dehydration step that removes excess water from the blood. In the fluid resuscitation step, dialysate is injected into the blood circuit to replenish the blood in the body.

[0140] The embodiments described above are merely illustrative, and the scope of these embodiments is not limited to the examples described. In addition to the described processes and components, additional processes and / or components may be added. Furthermore, without departing from the inventive concept, modifications may be made to the described processes and / or components, or certain processes and / or components may be omitted. Moreover, the order of the described processes may be changed. Additionally, the first and second backflow steps may be switched non-exclusively, and backflow may be performed for a portion of the time while the first and second backflow steps coexist (overlap).

[0141] Furthermore, the dialysis device of the embodiment is installed via a computer program executed by the control device 11; however, the computer program may also be stored in a non-transitory storage medium. Examples of non-transitory storage media include magnetic media such as read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor storage devices, built-in hard disks and removable disk devices, magneto-optical media, and optical media such as CD-ROM disks and digital multifunction disks (DVDs).

[0142] The embodiments described above are applied to blood purification devices that include at least a blood circuit, a dialysate circuit, and a control device to return blood remaining in the blood circuit back into the body.

[0143] Explanation of the labels:

[0144] The label 1 indicates a blood purifier;

[0145] The label 1a indicates the blood inlet;

[0146] The label 1b indicates the blood outlet;

[0147] The designation 1c indicates the dialysate inlet;

[0148] The designation 1d indicates the dialysis fluid discharge port;

[0149] Label 2 indicates the blood circuit;

[0150] The designation 2a indicates the debled circuit;

[0151] The label 2b indicates the reflux side circuit;

[0152] The label 3 indicates the dialysate circuit;

[0153] The designation 3a indicates the dialysate inlet circuit;

[0154] The designation 3b indicates the dialysate discharge circuit;

[0155] The number 4 indicates the fluid replenishment circuit;

[0156] The designation 4a indicates the rehydration circuit on the blood loss side;

[0157] The label 4b indicates the rehydration circuit on the side of blood return;

[0158] The number 5 indicates a blood pump;

[0159] The designation 6 indicates the dialysate supply section;

[0160] The number 7 indicates the primary air inlet section;

[0161] The designation 7a indicates an on / off valve;

[0162] The designation 7b indicates the airflow path;

[0163] The number 8 indicates the secondary air inlet section;

[0164] The designation 8a indicates a transfer pump;

[0165] The designation 8b indicates the airflow path;

[0166] The designation 8c indicates an on / off valve;

[0167] The designation 8d indicates an on / off valve;

[0168] The designation 8e indicates an air filter;

[0169] The designation 8F indicates an air filter;

[0170] The designation 9 indicates a compound pump;

[0171] The designation 10a indicates a dialysate filter;

[0172] The designation 10b indicates a dialysate filter;

[0173] The designation 11 indicates a control device;

[0174] The designation 12 indicates a replenishment pump;

[0175] The symbol P represents the dialysate port;

[0176] Symbols V1 to V7 represent on / off valves.

Claims

1. A blood purification device, comprising a blood circuit and a dialysate circuit, and a control device, wherein liquids can flow between the blood circuit and the dialysate circuit via a blood purification membrane of the blood purifier, characterized in that: The aforementioned blood circuit and the aforementioned dialysate circuit include a first flow path and a second flow path. The first flow path allows dialysate to flow from the aforementioned dialysate circuit into the aforementioned blood circuit via a connecting flow path. The connecting flow path bypasses the aforementioned blood purifier and connects the aforementioned dialysate circuit and the aforementioned blood circuit. The second flow path allows dialysate to flow from the aforementioned dialysate circuit into the aforementioned blood circuit via the aforementioned blood purification membrane. The aforementioned blood circuit includes pump number 1. The aforementioned dialysate circuit includes a second pump and a first valve. The above-mentioned connection flow path includes the second valve. The above-mentioned control device performs the following operations: Close the first valve and open the second valve to make the first pump rotate for the first time and stop the second pump from rotating for the second time. Control is performed so that the blood in the blood circuit is returned to the body by making the dialysate flow in one of the first flow path and the second flow path. Determine whether the flow rate of the dialysate has reached the predetermined flow rate; and Control is performed in response to the determination that the flow rate of the dialysate has reached the predetermined flow rate, thereby opening the first valve, closing the second valve, stopping the first pump from rotating first, and causing the second pump to rotate second, so that the dialysate flows in the other of the first flow path and the second flow path, thereby returning the blood in the blood circuit to the body.

2. The blood purification device according to claim 1, characterized in that, The blood purification device also includes: The dialysate supply unit is used to supply the dialysate to the dialysate circuit; and A dialysate filter for storing the dialysate supplied from the dialysate supply unit; The aforementioned control device controls the flow of dialysate stored in the dialysate filter into one of the first and second flow paths when the dialysate supply unit does not supply dialysate to the dialysate circuit. This allows the dialysate to return blood from the blood circuit to the body.

3. The blood purification device according to claim 1 or 2, characterized in that, The first flow path mentioned above also includes a flow path for the dialysate to flow from the dialysate circuit, through the connecting flow path, into the blood loss side circuit and the blood return side circuit; The second flow path mentioned above also includes a flow path for the dialysate to flow from the dialysate circuit into the return blood side circuit.

4. The blood purification device according to claim 1 or 2, characterized in that, The first flow path mentioned above also includes a flow path for the dialysate to flow from the dialysate circuit, through the connecting flow path, into the return blood side circuit and the blood loss side circuit; The second flow path mentioned above also includes a flow path for the dialysate to flow from the dialysate circuit into the blood removal side circuit.

5. The blood purification device according to claim 1 or 2, characterized in that, The first flow path mentioned above also includes a flow path for the dialysate to flow from the dialysate circuit, through the connecting flow path, into the blood loss side circuit and the blood return side circuit; The aforementioned blood circuit and the aforementioned dialysate circuit further include a third flow path, which allows the dialysate to flow from the aforementioned dialysate circuit, bypass the aforementioned blood purifier, and into the aforementioned return blood side circuit and the aforementioned blood removal side circuit via the aforementioned connecting flow path; The above-mentioned control device performs the following operations: Control is performed so that the blood in the blood circuit is returned to the body by causing the dialysate to flow in one of the first flow path and the third flow path. Determine whether the flow rate of the dialysate reaches the predetermined second flow rate; and Control is performed so that, in response to the determination that the flow rate of the dialysate has reached the predetermined second flow rate, the blood in the blood circuit is returned to the body by causing the dialysate to flow in the other of the first flow path and the third flow path.

6. The blood purification device according to claim 1 or 2, characterized in that, The second flow path mentioned above also includes a flow path for the dialysate to flow from the dialysate circuit into the return blood side circuit; The aforementioned blood circuit and dialysate circuit further include a fourth flow path for the dialysate to flow from the dialysate circuit, through the blood purification membrane, into the de-blood side circuit; The above-mentioned control device performs the following operations: Control is performed so that the blood in the blood circuit is returned to the body by causing the dialysate to flow in one of the second and fourth flow paths. Determine whether the flow rate of the dialysate reaches the predetermined third flow rate; and Control is performed so that, in response to the determination that the flow rate of the dialysate has reached the predetermined third flow rate, the blood in the blood circuit is returned to the body by causing the dialysate to flow in the other of the second and fourth flow paths.

7. The blood purification device according to claim 1 or 2, characterized in that, After blood purification treatment in the prescribed treatment mode, in order to return the blood in the blood circuit to the body, the control device selects one of the first flow path and the second flow path as the flow path of the dialysate according to the treatment mode.

8. The blood purification device according to claim 7, characterized in that, The above-mentioned control device performs the following operations: In the case where the above treatment mode refers to hemofiltration therapy or hemodiafiltration therapy, Control is performed to select the second flow path as the flow path for the dialysate, and by allowing the dialysate to flow through the second flow path, the blood in the blood circuit is returned to the body; and Control is performed so that, in response to the determination that the flow rate of the dialysate has reached the predetermined flow rate, the blood in the blood circuit is returned to the body by allowing the dialysate to flow in the first flow path.

9. A blood purification device, comprising a blood circuit and a dialysate circuit, and a control device, wherein liquids can flow between the blood circuit and the dialysate circuit via a blood purification membrane of the blood purifier, characterized in that: The aforementioned blood circuit and the aforementioned dialysate circuit include a first flow path and a second flow path. The first flow path allows dialysate to flow from the aforementioned dialysate circuit into the aforementioned blood circuit via a connecting flow path, which bypasses the aforementioned blood purifier and connects the aforementioned dialysate circuit and the aforementioned blood circuit. The second flow path allows dialysate to flow from the aforementioned dialysate circuit into the aforementioned blood circuit via the aforementioned blood purification membrane. The aforementioned blood circuit includes pump number 1. The aforementioned dialysate circuit includes a second pump and a first valve. The above-mentioned connection flow path includes the second valve. The above-mentioned control device performs the following operations: Close the first valve and open the second valve to make the first pump rotate for the first time and stop the second pump from rotating for the second time. Control is performed so that the blood in the blood circuit is returned to the body by making the dialysate flow in one of the first flow path and the second flow path. Determine whether the blood return flow has reached the predetermined return volume; and Control is performed so that, in response to the determination that the amount of blood returned has reached the predetermined blood return flow rate, the first valve is opened, the second valve is closed, the first pump stops its first rotation, and the second pump performs its second rotation. By causing the dialysate to flow in the other of the first and second flow paths, the blood in the blood circuit is returned to the body.

10. A control method for a blood purification device, the blood purification device comprising a blood circuit and a dialysate circuit, and a control device, wherein liquids can flow between the blood circuit and the dialysate circuit via a blood purification membrane of the blood purifier, characterized in that: The aforementioned blood circuit and the aforementioned dialysate circuit include a first flow path and a second flow path. The first flow path allows dialysate to flow from the dialysate circuit into the aforementioned blood circuit via a connecting flow path, which bypasses the aforementioned blood purifier and connects the aforementioned dialysate circuit and the aforementioned blood circuit. The second flow path allows dialysate to flow from the aforementioned dialysate circuit into the aforementioned blood circuit via the aforementioned blood purification membrane. The aforementioned blood circuit includes a pump, The following steps are performed using the aforementioned control device, and these steps include: The step of controlling the flow of blood in the blood circuit to the de-bleeding side or the return side by rotating the pump and causing the dialysate to flow in one of the first flow path and the second flow path. The step of determining whether the flow rate of the dialysate reaches a predetermined flow rate; and In response to the determination that the flow rate of the dialysate has reached the predetermined flow rate, the pump is stopped rotating, and the blood in the blood circuit is returned to the de-bleeding side or the return side by allowing the dialysate to flow in the other of the first flow path and the second flow path.

11. A control method for a blood purification device, the blood purification device comprising a blood circuit and a dialysate circuit, and a control device, wherein liquids can flow between the blood circuit and the dialysate circuit via a blood purification membrane of the blood purifier, characterized in that: The aforementioned blood circuit and dialysate circuit include a first flow path and a second flow path. The first flow path allows dialysate to flow from the dialysate circuit into the blood circuit via a connecting flow path, which bypasses the blood purifier and connects the dialysate circuit and the blood circuit. The second flow path allows dialysate to flow from the dialysate circuit into the blood circuit via the blood purification membrane. The aforementioned blood circuit includes a pump, The following steps are performed using the aforementioned control device, and these steps include: The step of controlling the flow of blood in the blood circuit to the de-bleeding side or the return side by rotating the pump and causing the dialysate to flow in one of the first flow path and the second flow path. The steps for determining whether the blood return flow rate reaches the predetermined blood return volume; and In response to the situation where the amount of blood returned has reached the predetermined amount, the pump is stopped rotating, and the blood in the blood circuit is returned to the de-bleeding side or the return side by allowing the dialysate to flow in the other of the first flow path and the second flow path.

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