dialysis device

Abstract

To use a dialysis machine including a dialysate container, with a supply chamber, collection chamber and variable volume chamber formed therein to enable use of backfiltration replacement fluid.SOLUTION: When executing a supply drainage step (Fig. 6(a) and (b)) of storing dialysate in a supply chamber 11a of a first dialysate container 11, control means C controls a positive-displacement pump 13A to reduce the volume of a variable volume chamber 11c by a prescribed amount equivalent to replacement fluid (for example: 120 ml) and increase the volume of the supply chamber 11a by the amount equivalent to the replacement fluid (Fig. 6(b): 280 ml+120 ml), Subsequently, when executing a liquid supply recovery step of supplying the dialysate to a dialyzer 2, the control means C controls the positive-displacement pump 13A to increase the volume of the variable volume chamber 11c by the prescribed amount equivalent to the replacement fluid (120 ml) and discharge the dialysate by the amount equivalent to the replacement fluid from the supply chamber 11a to the dialyzer 2 (Fig. 6(c): 280 ml+120 ml).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a dialysis machine, and more particularly to a dialysis machine having a dialysate container in which a supply chamber, a collection chamber, and a variable volume chamber are formed. [Background technology]

[0002] Conventionally, a dialysis device used in hemodialysis treatment has been known that has a dialysis fluid container formed with a supply chamber for storing fresh dialysis fluid, a collection chamber for collecting used dialysis fluid, and a variable volume chamber formed between the supply chamber and the collection chamber (Patent Document 1). The variable volume chamber contains a liquid such as silicone oil, and when the liquid is pumped in or out of the variable volume chamber using a positive displacement pump, the volume of the variable volume chamber increases or decreases, thereby varying the storage volumes of the adjacent supply and recovery chambers. For example, by reducing the volume of the variable volume chamber, used dialysis fluid can be drawn into the collection chamber for dehydration in the dialyzer, or raw dialysis fluid can be drawn into the supply chamber for preparation of fresh dialysis fluid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-18540 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, there are cases where patients are given dialysis fluid replacement during dialysis treatment. One method of such replacement is known as backfiltration replacement, in which a dialyzer whose interior is separated by a semipermeable membrane (dialysis membrane) into a dialysate chamber connected to a dialysate circuit and a blood chamber connected to a blood circuit is used, and the dialysate is transferred from the dialysate circuit of the dialyzer to the blood circuit across the semipermeable membrane to perform replacement. To perform this backfiltration, when fresh dialysate is supplied from the supply chamber of the dialysate container to the dialyzer, the dialysate must be supplied so that the dialysate circuit in the dialyzer has a higher positive pressure than the blood circuit. However, the dialysis machine of Patent Document 1 does not anticipate the use of a positive displacement pump to perform backfiltration fluid replacement. In view of these problems, the present invention provides a dialysis machine capable of performing backfiltration replacement fluid using a dialysate container having a supply chamber, a recovery chamber, and a variable volume chamber formed therein. [Means for solving the problem]

[0005] That is, the dialysis device according to claim 1 comprises a dialysate container having a supply chamber, a collection chamber, and a variable volume chamber formed therein; a supply passage connected to the supply chamber for supplying fresh dialysate to the supply chamber; a supply passage connected to the supply chamber for supplying fresh dialysate to the dialyzer; a collection passage connected to the collection chamber for collecting used dialysate from the dialyzer; a drainage passage connected to the collection chamber for draining used dialysate; a positive displacement pump for feeding and discharging liquid in the variable volume chamber; and control means for controlling the positive displacement pump. In a dialysis apparatus, the dialysate container alternately performs a supply / drain step of storing fresh dialysate in the supply chamber and draining used dialysate from the collection chamber, and a supply / recovery step of supplying fresh dialysate from the supply chamber to the dialyzer and recovering used dialysate in the collection chamber, During the supply / drain step, the control means controls the positive displacement pump to reduce the volume of the variable volume chamber by a predetermined amount equivalent to replacement fluid, and increase the volume of the supply chamber by the amount equivalent to replacement fluid; During the fluid supply and recovery process, the control means controls the positive displacement pump to increase the volume of the variable volume chamber by an amount equivalent to a predetermined amount of replacement fluid, thereby discharging the amount of dialysis fluid equivalent to the replacement fluid from the supply chamber to the dialyzer. [Effects of the Invention]

[0006] According to the above invention, by reducing the volume of the variable volume chamber by a predetermined amount equivalent to replacement fluid during the supply and drainage process, the volume of the supply chamber can be increased by that amount, and the dialysis fluid required for replacement fluid can be stored in the supply chamber. During the fluid supply and recovery process, the volume of the variable volume chamber is increased by an amount equivalent to the replacement fluid, so that an amount of dialysis fluid equivalent to the replacement fluid can be discharged from the supply chamber toward the dialyzer, generating a pressure difference in the dialyzer and enabling the backfiltration replacement fluid to be performed. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a circuit diagram of a dialysis machine showing an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the positive displacement pump of FIG. 1. [Figure 3] FIG. 2 is a diagram showing the operation of a positive displacement pump during normal dialysis treatment using the dialysis machine of FIG. 1. [Figure 4] FIG. 2 is a diagram showing the operation of the positive displacement pump during backfiltration replacement using the dialysis apparatus of FIG. 1. [Figure 5] FIG. 10 is a diagram showing the operation of a positive displacement pump during normal dialysis treatment in the second embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing the operation of the positive displacement pump during backfiltration replacement in the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows a fluid circuit constituting a dialysis device 1 used for hemodialysis treatment, which comprises a dialyzer 2 for performing hemodialysis, a dialysate circuit 3 for circulating dialysate through the dialyzer 2, and a blood circuit 4 for circulating blood through the dialyzer 2. The operation of the dialysis machine 1 is controlled by a control means C such as a computer that executes processing according to a required program. As the control means C, a computer system such as a microcontroller or a microcomputer can be used. The dialyzer 2 is divided by a semipermeable membrane (dialysis membrane) into a dialysate chamber connected to the dialysate circuit and a blood chamber connected to the blood circuit. The blood circuit 4 has an arterial circuit 4A that sends blood from the patient to the dialyzer 2, and a venous circuit 4B that returns blood from the dialyzer 2 to the patient, and the arterial circuit 4A is provided with a blood pump BP.

[0009] The dialysis fluid circuit 3 is provided with a first dialysis fluid container 11 and a second dialysis fluid container 12 as dialysis fluid containers, and the interior of each is partitioned by two diaphragms (movable partitions) into supply chambers 11a, 12a that store fresh dialysis fluid, collection chambers 11b, 12b that collect used dialysis fluid, and variable volume chambers 11c, 12c that are formed between the supply chambers 11a, 12a and the collection chambers 11b, 12b. The variable volume chambers 11c and 12c each contain a liquid such as silicone oil, and the volumes of the variable volume chambers 11c and 12c can be varied by injecting or evacuating the liquid using positive displacement pumps 13A and 13B connected to the chambers. For example, when the volume of the variable volume chambers 11c, 12c is reduced by extracting liquid from the variable volume chambers 11c, 12c, the volume of the supply chambers 11a, 12a or the recovery chambers 11b, 12b increases.

[0010] The dialysate circuit 3 includes a supply passage 5 for supplying dialysis water to the supply chambers 11a, 12a of the first and second dialysate containers 11, 12, a concentrate A passage 6 for supplying concentrate A to the supply chambers 11a, 12a via the supply passage 5, a concentrate B passage 7 for supplying concentrate B to the supply chambers 11a, 12a via the supply passage 5, a supply passage 8 for supplying fresh dialysate from the supply chambers 11a, 12a to the dialyzer 2, a recovery passage 9 for recovering used dialysate that has passed through the dialyzer 2 into the recovery chambers 11b, 12b, and a drainage passage 10 for draining the used dialysate from the recovery chambers 11b, 12b. The dialysis machine 1 of this embodiment is a so-called personal dialysis machine that prepares fresh dialysis fluid in the first and second dialysis fluid containers 11 and 12, and prepares fresh dialysis fluid by mixing dialysis water and dialysis fluid concentrate inside the supply chambers 11a and 12a. The water used for dialysis is purified water such as RO water, and the concentrate solutions used for dialysis are composed of two types of concentrate solution: concentrate A, which contains calcium chloride and is primarily composed of sodium chloride, and concentrate B, which is an aqueous solution of sodium bicarbonate. Inside the supply chambers 11a and 12a, the raw solution A, raw solution B and dialysis water are mixed in a ratio of, for example, 1:1.26:32.74 to prepare fresh dialysis fluid.

[0011] The supply passage 5 is provided with a supply pump 22 for delivering the dialysis water, and the downstream portion of the supply passage 5 branches in two directions and is connected to the supply chambers 11a and 12a of the first and second dialysis fluid containers 11 and 12. The A concentrate solution passage 6 and the B concentrate solution passage 7 are connected to the supply passage 5 in a section between the supply pump 22 and the first and second dialysis fluid containers 11, 12, and the A concentrate solution passage 6 is connected to an A concentrate solution container 23 serving as a concentrate solution supply means containing the A concentrate solution, and the B concentrate solution passage 7 is connected to a B concentrate solution container 24 serving as a concentrate solution supply means containing the B concentrate solution. As a means for supplying the raw solution A and raw solution B, a liquid supply facility or supply device provided in the treatment facility where the dialysis machine 1 is installed can also be used. A first on-off valve V1 is provided in the supply passage 5 between the supply fluid pump 22 and the connection point of the A concentrate passage 6, and supply valves V2 and V3 are provided in the passages branching off to the supply chambers 11a and 12a of the first and second dialysis fluid containers 11 and 12, respectively. Furthermore, a A concentrate supply valve V4 is provided in the A concentrate passage 6, and a B concentrate supply valve V5 is provided in the B concentrate passage 7.

[0012] The upstream portion of the fluid supply passage 8 branches into two directions and is connected to the supply chambers 11a and 12a of the first and second dialysate containers 11 and 12, respectively, and the downstream end is connected to the dialyzer 2. Fluid supply valves V6 and V7 are provided at the branched portions, respectively. The recovery passage 9 has an upstream end connected to the dialyzer 2, and a downstream portion branching in two directions to be connected to the recovery chambers 11b and 12b of the first and second dialysate containers 11 and 12. A dialysate pump 27 for pumping used dialysate is provided, and recovery valves V10 and V11 are provided at the branched portions. A sealed circuit is formed by the supply chambers 11a, 12a, the supply passage 8, the dialyzer 2, the recovery passage 9, and the recovery chambers 11b, 12b. When the dialysate pump 27 is operated, the dialysate flows from the supply chambers 11a, 12a to the recovery chambers 11b, 12b via the dialyzer 2. The upstream portion of the drainage passage 10 branches into two directions and is connected to the collection chambers 11b and 12b of the first and second dialysate containers 11 and 12, respectively, and the downstream end is connected to a drainage pipe installed in a treatment facility. In addition, drainage valves V12 and V13 are provided at the branched portions.

[0013] Next, FIG. 2 shows a positive displacement pump 13A that injects and discharges liquid into and from the variable volume chamber 11c of the first dialysis fluid container 11, and a positive displacement pump 13B connected to the variable volume chamber 12c of the second dialysis fluid container 12 also has the same configuration. The positive displacement pump 13A comprises a cylindrical housing 31, a piston 32 arranged inside the housing 31 so as to be able to move back and forth, and a motor 33 for moving the piston 32 back and forth, and the operation of the motor 33 is controlled by the control means C. A cylinder chamber 31a for accommodating a liquid (silicone oil) is formed below the housing 31 in the figure, and the tip of the cylinder chamber 31a is tapered and is connected to the variable volume chamber 11c of the first dialysis fluid container 11 via piping.

[0014] The piston 32 includes a main body 32a having a through hole formed in the center through which a ball screw 33a connected to the drive shaft of the motor 33 can pass, a cap 32b that closes the tip end of the main body 32a, and a ball nut 32c that is provided at the rear end of the main body 32a and engages with the ball screw 33a. A guide rod 34 serving as a dog is fixed to the side of the ball nut 32c toward the outer periphery, and this guide rod 34 is inserted into a guide hole 31b formed in the housing 31 in the vertical direction. This prevents the ball nut 32c from rotating in accordance with the rotation of the ball screw 33a, and also guides the up and down movement of the piston 32 including the ball nut 32c. Furthermore, an origin sensor 35 that detects the approach of the guide rod 34 is provided at a predetermined position in the up and down direction (axial direction) of the housing 31. A plurality of diaphragms 36 are provided between the outer periphery of the piston 32 and the inner periphery of the housing 31, thereby maintaining a liquid-tight seal between the piston 32 and the housing 31 and allowing the piston 32 to move back and forth in the vertical direction within the housing 31. Furthermore, a disk-shaped disc 33b is provided on the drive shaft of the motor 33, and the rotational position of the disc 33b is detected by a photoelectric sensor 37 fixed to the housing 31 side.

[0015] According to the positive displacement pump 13A having the above-described configuration, when the motor 33 is rotated in the reverse direction, the piston 32 moves backward, and the liquid (silicone oil) is drawn out of the variable volume chamber 11c into the cylinder chamber 31a, thereby reducing the volume of the variable volume chamber 11c. Conversely, when the motor 33 is rotated in the forward direction, the piston 32 moves forward, and the liquid in the cylinder chamber 31a is injected into the variable volume chamber 11c, thereby increasing the volume of the variable volume chamber 11c. The control means C recognizes the position of the piston 32 from the rotation angle in the forward and reverse directions of the drive shaft of the motor 33, and when the piston 32 reaches the origin position, which is the forward end, the origin sensor 35 detects the guide rod 34 as a dog, and the control means C detects that the piston 32 has reached the origin position. When the piston 32 reaches the origin position, the liquid in the cylinder chamber 31a is discharged and the volume of the variable volume chamber 11c becomes maximum, and the volume of the variable volume chamber 11c at this time is called the origin volume.

[0016] In the dialysis device 1 having the above-described configuration, the first and second dialysate containers 11, 12 are operated as follows to cause the dialysate to flow through the dialysate circuit 3. 3 is a diagram illustrating the operation of the first dialysate container 11 during normal dialysis treatment, i.e., when water removal or backfiltration replacement fluid, which will be described later, is not performed. Note that the operation of the second dialysate container 12 is similar, and therefore its description will be omitted. 3(a) to 3(d) show the operation of preparing fresh dialysis fluid in the supply chamber 11a and draining used dialysis fluid from the collection chamber 11b. The operation from when the supply chamber 11a is filled with fresh dialysis fluid until the entire amount of used dialysis fluid is drained from the collection chamber 11b and the flow of the fluid stops is called the supply and drain process. In contrast, FIG. 3(e) shows the operation of supplying fresh dialysis fluid prepared in the supply chamber 11a to the dialyzer 2 and recovering used dialysis fluid from the dialyzer 2 to the recovery chamber 11b. The operation from when the recovery chamber 11b is filled with used dialysis fluid and the entire amount of fresh dialysis fluid is discharged from the supply chamber 11a and the flow of the fluid stops is called the fluid supply recovery process. The dialysate flows through the dialysate circuit 3 by alternately repeating the water supply / drainage process and the fluid supply / recovery process in the first and second dialysate containers 11, 12.

[0017] FIG. 3(a) shows the operation of causing dialysis water to flow into the supply chamber 11a. The state immediately before this Figure 3(a) is the state shown in Figure 3(e) described below, in which the collection chamber 11b is filled with used dialysis fluid, and conversely, all of the fresh dialysis fluid has been discharged from the supply chamber 11a. From this state, the control means C opens the supply valve V2 of the supply passage 5 connected to the supply chamber 11a and closes the supply valve V6 of the supply passage 8, so that dialysis water delivered by the supply pump 22 flows into the supply chamber 11a from the supply passage 5. Meanwhile, the control means C closes the recovery valve V10 of the recovery passage 9 connected to the recovery chamber 11b and opens the drain valve V12 of the drain passage 10, so that the used dialysis fluid in the recovery chamber 11b is pushed out into the drain passage 10 as the volume of the supply chamber 11a increases. Furthermore, the piston 32 of the positive displacement pump 13A connected to the variable volume chamber 11c remains at the origin position.

[0018] FIG. 3(b) shows the operation of flowing concentrate B, out of the concentrate dialysis fluid, into the supply chamber 11a. The control means C closes the drain valve V12 of the drain passage 10, opens the B raw solution supply valve V5, and moves the piston 32 of the positive displacement pump 13A back a predetermined distance from the home position. Then, the liquid in the variable volume chamber 11c is sucked into the cylinder chamber 31a of the positive displacement pump 13A, and a predetermined amount of concentrate B is supplied to the supply chamber 11a via the concentrate B passage 7 and the supply passage 5. Here, the supply chambers 11a, 12a and the collection chambers 11b, 12b of the first and second dialysate containers 11, 12 in this embodiment are each capable of containing 280 ml of liquid. To prepare 280 ml of fresh dialysis fluid by flowing dialysis water, stock solution A, and stock solution B into the supply chamber 11a in the aforementioned proportions, the positive displacement pump 13A reduces the volume of the variable volume chamber 11c by 10.08 ml, thereby flowing 10.08 ml of solution B into the supply chamber 11a.

[0019] FIG. 3(c) shows the operation of flowing concentrate A out of the dialysis concentrate solutions into the supply chamber 11a. The control means C keeps the drain valve V12 of the drain passage 10 closed, closes the B concentrate supply valve V5, opens the A concentrate supply valve V4, and further retracts the piston 32 of the positive displacement pump 13A by a predetermined amount, causing the liquid in the variable volume chamber 11c to be sucked into the cylinder chamber 31a of the positive displacement pump 13A. As a result, the concentrate solution A is supplied to the supply chamber 11a via the concentrate solution A passage 6 and the supply passage 5, and in this embodiment, 8 ml of concentrate solution A is caused to flow into the supply chamber 11a to prepare 280 ml of fresh dialysis solution.

[0020] FIG. 3(d) shows the operation of causing the remaining dialysis water for preparing the dialysis solution to flow into the supply chamber 11a. The control means C opens the drain valve V12 of the drain passage 10 and closes the raw solution A supply valve V4. As a result, dialysis water delivered by the liquid supply pump 22 flows into the supply chamber 11a from the supply passage 5, filling the supply chamber 11a with liquid (280 ml), while the used dialysis fluid in the recovery chamber 11b is discharged through the drainage passage 10, leaving it empty (0 ml). Here, dialysis water is flowed into the supply chamber 11a by the operations shown in Figures 3(a) and 3(d) above, and as a result, 280 ml of fresh dialysis fluid is prepared inside the supply chamber 11a by mixing the stock solution A, stock solution B, and dialysis water in a predetermined ratio. Here, when performing normal dialysis treatment, while dialysis water flows into the supply chamber 11a in the operation of Figure 3(d), the control means C advances the piston 32 of the positive displacement pump 13A to the origin position, and returns the variable volume chamber 11c to its origin volume.

[0021] FIG. 3(e) shows the operation of the fluid supply and recovery process in which fresh dialysis fluid prepared in the supply chamber 11a is supplied to the dialyzer 2 and used dialysis fluid is recovered from the dialyzer 2 into the recovery chamber 11b. From the state shown in Figure 3(d), the control means C closes the supply valve V2 of the supply passage 5 connected to the supply chamber 11a and opens the liquid supply valve V6 of the liquid supply passage 8, thereby starting the supply of fresh dialysis fluid from the liquid supply passage 8 to the dialyzer 2. Meanwhile, the control means C opens the recovery valve V10 of the recovery passage 9 connected to the recovery chamber 11b and closes the drain valve V12 of the drain passage 10, so that the used dialysis fluid pumped by the dialysis fluid pump 27 flows into the recovery chamber 11b from the recovery passage 9. As a result, the volume of the collection chamber 11b becomes full (280 ml) due to the inflow of used dialysate, and the entire volume of fresh dialysate is discharged from the supply chamber 11a, leaving it empty (0 ml). During normal dialysis treatment, in the fluid supply / recovery process, piston 32 of positive displacement pump 13A connected to variable volume chamber 11c is located at the origin position, and variable volume chamber 11c maintains its origin volume. When the supply chamber 11a becomes empty and the collection chamber 11b becomes full with used dialysis fluid in this way, the operations shown in Figures 3(a) to 3(e) are repeated, and the first dialysis fluid container 11 and the second dialysis fluid container 12 alternately supply fresh dialysis fluid to the dialyzer 2 and collect used dialysis fluid from the dialyzer 2.

[0022] Next, the dialysis device 1 of this embodiment is capable of removing water during dialysis treatment. By generating a pressure difference between the blood circuit 4 and the liquid supply passage 8 and recovery passage 9 in the dialyzer 2, the water in the blood circulating through the blood circuit 4 is moved across the semipermeable membrane of the dialyzer 2 to the liquid supply passage 8 and recovery passage 9 side, thereby removing water. Although the illustrated explanation is omitted, during the liquid supply and recovery process shown in Figure 3(e), the control means C controls the positive displacement pump 13A to move the piston 32 backward based on the pre-set amount of water to be removed. This reduces the volume of the variable volume chamber 11c, and by drawing the reduced volume of liquid into the recovery chamber 11b, a pressure difference is created between the blood circuit 4 and the liquid supply passage 8 and recovery passage 9 in the dialyzer 2, causing the water in the blood to move toward the liquid supply passage 8 and recovery passage 9, thereby removing the water. Furthermore, when the water removal operation is performed, the control means C advances the piston 32 of the positive displacement pump 13A from the retracted position to the origin position while supplying dialysis water to the supply chamber 11a shown in Figure 3(a), thereby returning the volume of the variable volume chamber 11c to the origin volume.

[0023] FIG. 4 shows the operation of the dialysis device 1 of this embodiment when backfiltration replacement fluid is performed during dialysis treatment. Backfiltration fluid replacement refers to the process of generating a pressure difference between the fluid supply passage 8 and the recovery passage 9 and the blood circuit 4 in the dialyzer 2 during dialysis treatment, causing the dialysis fluid in the fluid supply passage 8 to move across the semipermeable membrane of the dialyzer 2 into the blood circuit 4 and provide fluid replacement to the patient. In this embodiment, backfiltration replacement fluid is administered at predetermined intervals during dialysis treatment, for example, 200 ml of backfiltration replacement fluid is administered every 30 minutes after 20 to 30 minutes have elapsed since the start of dialysis treatment. Therefore, if dialysis treatment is performed for four hours, a total of 1,400 ml of fresh dialysate can be administered.

[0024] First, FIG. 4(a) shows the operation of causing dialysis water to flow into the supply chamber 11a through the supply passage 5, similar to FIG. 3(a). At this time, the piston 32 of the positive displacement pump 13A is stopped at the origin position, and the volume of the variable volume chamber 11c does not change.

[0025] Next, FIG. 4(b) shows the operation of causing the B stock solution to flow into the supply chamber 11a, similar to FIG. 3(b). When performing the backfiltration replacement fluid, the control means C moves the piston 32 of the positive displacement pump 13A further backward by an amount corresponding to the amount of replacement fluid compared to that in Figure 3(b), thereby further reducing the volume of the variable volume chamber 11c. Specifically, during normal dialysis treatment, the inflow amount of concentrate B is 10.08 ml, whereas when backfiltration replacement fluid is performed, 14.4 ml of concentrate B, which is 3.6 ml more, is allowed to flow into the supply chamber 11a.

[0026] Next, FIG. 4(c) shows the operation of causing the A concentrate solution to flow into the supply chamber 11a, similar to FIG. 3(c). In this case, the control means C also moves the piston 32 of the positive displacement pump 13A further backward by an amount corresponding to the amount of replacement fluid compared to that in Figure 3(c) above, thereby further reducing the volume of the variable volume chamber 11c. Specifically, during normal dialysis treatment, the inflow amount of concentrate A is 8 ml, whereas when backfiltration replacement fluid is performed, 11.43 ml of concentrate A, which is 3.43 ml more, is allowed to flow into the supply chamber 11a.

[0027] FIG. 4(d) shows the operation of causing the remaining dialysis water to flow into the supply chamber 11a to prepare the dialysis solution, similar to FIG. 3(d). During normal dialysis treatment as shown in Figure 3(d), the control means C advances the piston 32 of the positive displacement pump 13A from the retracted position to the origin position, but when backfiltration replacement fluid is performed, the control means C further retracts the piston 32 of the positive displacement pump 13A, thereby further reducing the volume of the variable volume chamber 11c. Specifically, the volume of the variable volume chamber 11c is reduced so that 94.17 ml of dialysis water flows into the supply chamber 11a, thereby allowing a total of 400 ml of liquid to be contained in the supply chamber 11a. In this way, in the operation of Figures 4(b) to (d), 3.6 ml of solution B, 3.43 ml of solution A, and 94.17 ml of dialysis water are allowed to flow in, compared to normal dialysis treatment. The proportions of the additionally introduced solution B, solution A, and dialysis water correspond to their respective proportions in the fresh dialysis fluid, so that a total of 400 ml of fresh dialysis fluid is prepared in the supply chamber 11a, which is 120 ml of replacement fluid compared to normal dialysis treatment.

[0028] FIG. 4(e) shows the operation of supplying fresh dialysis fluid prepared in the supply chamber 11a to the dialyzer 2, recovering used dialysis fluid from the dialyzer 2 to the recovery chamber 11b, and then performing backfiltration replacement fluid using the fresh dialysis fluid in an amount equivalent to the replacement fluid prepared in the dialyzer 2. From the state shown in Figure 4(d), the control means C closes the supply valve V2 of the supply passage 5 connected to the supply chamber 11a and opens the liquid supply valve V6 of the liquid supply passage 8, thereby starting the supply of fresh dialysis fluid from the liquid supply passage 8 to the dialyzer 2. Meanwhile, the control means C opens the recovery valve V10 of the recovery passage 9 connected to the recovery chamber 11b and closes the drain valve V12 of the drain passage 10, so that the used dialysis fluid delivered by the fluid supply pump 22 flows into the recovery chamber 11b from the recovery passage 9. During this liquid supply / recovery process, the control means C moves the piston 32 of the positive displacement pump 13A to the origin position, thereby returning the volume of the variable volume chamber 11c to the origin volume. As a result, 400 ml of fresh dialysis fluid stored in the supply chamber 11a is supplied to the dialyzer 2, and 120 ml of dialysis fluid, which is the difference from the 280 ml capacity of the supply chamber 11a in normal dialysis treatment and corresponds to the amount of replacement fluid, moves from the dialysis fluid circuit 3 to the blood circuit 4 in the dialyzer 2, thereby performing replacement fluid.

[0029] Here, since the above-described operation shown in Figures 4(a) to (e) can only provide 120 ml of fluid replacement, an additional 80 ml of fluid replacement is required to provide 200 ml of fluid replacement in one fluid replacement operation. In the dialysis device 1 of this embodiment, the same operations as those shown in Figures 4(a) to (e) performed on the first dialysate container 11 are also performed on the second dialysate container 12, thereby replacing the missing 80 ml of fresh dialysate. That is, in the second dialysate container 12 as well, the positive displacement pump 13B connected to the variable volume chamber 12c is operated in accordance with the operations shown in FIGS. 4(a) to 4(e). However, the amount of retraction of the piston 32 of the positive displacement pump 13B at this time needs to be set in accordance with the proportions of Solution B, Solution A, and dialysis water for preparing fresh dialysis solution, at a ratio for preparing 360 ml of fresh dialysis solution by adding 80 ml to 280 ml. In addition, in order to prepare 200 ml of additional fresh dialysis fluid in one fluid replacement operation, 100 ml of additional fresh dialysis fluid may be prepared in the first dialysis fluid container 11, and then 100 ml of additional fresh dialysis fluid may be prepared in the second dialysis fluid container 12.

[0030] As described above, according to the dialysis device 1 of the present embodiment, backfiltration replacement fluid can be performed in the dialyzer 2 by increasing or decreasing the volumes of the variable volume chambers 11c and 12c by controlling the operation of the positive displacement pumps 13A and 13B connected to the first dialysate container 11 and the second dialysate container 12. In contrast, in the conventional dialysis device 1, as shown in FIG. 3, additional fresh dialysate for backfiltration replacement fluid is not prepared in the supply and drain steps shown in FIGS. 3(a) to 3(d). Furthermore, since the piston 32 of the positive displacement pump 13A is returned to its original position in FIG. 3(d), the piston 32 cannot be advanced any further in FIG. 3(e), and additional fresh dialysis fluid for backfiltration replacement fluid cannot be sent to the dialyzer 2.

[0031] Next, FIGS. 5 and 6 show a second embodiment of the present invention. The dialysis machine 1 according to the first embodiment is a so-called personal dialysis machine, in which fresh dialysis fluid is prepared by mixing dialysis water, stock solution A, and stock solution B in the supply chambers 11a and 12a of the first and second dialysis fluid containers 11 and 12, respectively. On the other hand, the dialysis machine 1 according to the second embodiment is a so-called console-type dialysis machine, in which pre-prepared fresh dialysis fluid is supplied to the supply chambers 11a and 12a from a dialysis fluid supply device installed in a hospital or the like. FIG. 5 shows the operation of the dialysis device 1 according to the first embodiment, corresponding to FIG. 3, during normal dialysis treatment, and FIG. 6 shows the operation during backfiltration replacement fluid, corresponding to FIG.

[0032] FIG. 5(a) shows a supply / drain step, in which fresh dialysate flows into the supply chamber 11a and used dialysate is drained from the collection chamber 11b. As in the dialysis device 1 of the first embodiment, the control means C closes the supply valve V6 and the recovery valve V10 and opens the supply valve V2 and the drain valve V12, thereby supplying the supply chamber 11a with fresh dialysate prepared in advance until it is full (280 ml), and emptying the recovery chamber 11b (0 ml). FIG. 5(b) shows a fluid supply and recovery step, which shows the operation of supplying fresh dialysate from the supply chamber 11a to the dialyzer 2 and recovering used dialysate from the dialyzer 2 to the recovery chamber 11b. As in the dialysis device 1 of the first embodiment, the control means C opens the supply valve V6 and the recovery valve V10 and closes the supply valve V2 and the drain valve V12. As a result, fresh dialysate is supplied to the dialyzer 2 through the supply passage 8, and used dialysate is recovered through the recovery passage 9 in an amount (280 ml) that fills the recovery chamber 11b. During normal dialysis treatment using the dialysis device 1 shown in Figure 5, there is no need to change the volumes of the variable volume chambers 11c and 12c, and the piston 32 of the positive displacement pump 13A remains positioned at the origin position in Figures 5(a) and 5(b).

[0033] Next, the operation of the dialysis apparatus 1 according to the second embodiment when backfiltration replacement fluid is performed will be described with reference to FIG. 6(a) and 6(b) show a supply / drain step, in which fresh dialysate flows into the supply chamber 11a and used dialysate is drained from the collection chamber 11b. FIG. 6(a) shows, as in FIG. 5(a), the operation of flowing 280 ml of fresh dialysate into the supply chamber 11a, the same amount as that used in normal dialysis treatment, and FIG. 6(b) shows the operation of flowing 120 ml of fresh dialysate into the supply chamber 11a, the amount corresponding to the replacement fluid used for backfiltration replacement fluid. In FIG. 6(a), when a predetermined amount of fresh dialysate flows into the supply chamber 11a, the control means C moves the piston 32 of the positive displacement pump 13A backward by a predetermined amount, thereby reducing the volume of the variable volume chamber 11c. In this embodiment, the volume of the variable volume chamber 11c is reduced by 120 ml, the same as in the first embodiment, so that the supply chamber 11a can hold 400 ml of fresh dialysis fluid, which is 120 ml more than the 280 ml used in normal dialysis treatment.

[0034] FIG. 6(c) shows a fluid supply and recovery step, which shows the operation of supplying fresh dialysate from the supply chamber 11a to the dialyzer 2 and recovering used dialysate from the dialyzer 2 to the recovery chamber 11b. The control means opens the supply valve V6 and the recovery valve V10 and closes the supply valve V2 and the drain valve V12, whereby fresh dialysate is supplied from the supply chamber 11a to the dialyzer 2 via the supply passage 8, and used dialysate is recovered in the recovery chamber 11b via the recovery passage 9. In accordance with this operation, the control means C advances the piston 32 of the positive displacement pump 13A to the origin position, and returns the volume of the variable volume chamber 11c to the origin volume. As a result, 400 ml of fresh dialysate is supplied from the supply chamber 11a to the dialyzer 2 via the supply passage 8, and 120 ml of fresh dialysate, equivalent to the replacement fluid, is backfiltered through the dialyzer 2 to provide replacement fluid.

[0035] In the second embodiment, in the operation of backfiltration replacement fluid, it is not necessary to use the entire amount of fresh dialysate prepared by adding it to the fresh dialysate used during normal dialysis treatment as backfiltration replacement fluid. In other words, if 120 ml of additional fresh dialysis fluid is prepared, only 100 ml of this is used as backfiltration replacement fluid, and the remaining 20 ml is left in the supply chamber 11a and can be used for subsequent backfiltration replacement fluid. [Explanation of symbols]

[0036] 1 Dialysis machine 2 Dialysis machine 3 Dialysate circuit 4 Blood circuit 11 First dialysate container 12 Second dialysate container 11a, 12a Supply room 11b, 12b Recovery room 11c, 12c Variable volume chamber 13A, 13B Positive displacement pump C. Control measures

Claims

1. a dialysate container having a supply chamber, a collection chamber, and a variable volume chamber formed therein; a supply passage connected to the supply chamber for supplying fresh dialysate to the supply chamber; a supply passage connected to the supply chamber for supplying fresh dialysate to a dialyzer; a collection passage connected to the collection chamber for collecting used dialysate from the dialyzer; a drain passage connected to the collection chamber for draining used dialysate; a positive displacement pump for feeding and discharging liquid in the variable volume chamber; and control means for controlling the positive displacement pump. In a dialysis apparatus, the dialysate container alternately performs a supply / drain step of storing fresh dialysate in the supply chamber and draining used dialysate from the collection chamber, and a supply / recovery step of supplying fresh dialysate from the supply chamber to the dialyzer and recovering used dialysate in the collection chamber, During the supply / drain step, the control means controls the positive displacement pump to reduce the volume of the variable volume chamber by a predetermined amount equivalent to replacement fluid, and increase the volume of the supply chamber by the amount equivalent to replacement fluid; During the fluid supply and recovery step, the control means controls the positive displacement pump to increase the volume of the variable volume chamber by an amount equivalent to a predetermined amount of replacement fluid, thereby discharging the amount of dialysis fluid equivalent to the replacement fluid from the supply chamber to the dialyzer.

2. Dialysis water for preparing fresh dialysis fluid is circulated through the supply passage, and a concentrate supply means is provided for supplying a concentrate solution for dialysis fluid for preparing the fresh dialysis fluid to the supply passage, so that the dialysis water and the concentrate solution for dialysis fluid are mixed inside the supply chamber of the dialysis fluid container to prepare the fresh dialysis fluid. When dialysis water flows into the supply chamber from the supply passage, the control means controls the positive displacement pump to reduce the volume of the variable volume chamber based on the ratio of dialysis water to the amount of dialysis fluid equivalent to the replacement fluid, 2. The dialysis device according to claim 1, wherein when the dialysis concentrate flows into the supply chamber from the supply passage, the volume of the variable volume chamber is reduced by controlling the positive displacement pump based on the proportion of the dialysis concentrate in the amount of dialysis solution equivalent to the replacement fluid.

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