Method for checking the connections of dialysis machines and fluid replacement pathways.

Abstract

To easily and reliably detect a connection destination of a fluid replacement passage.SOLUTION: A fluid replacement passage 27A relates to a dialysis device 1 which is selectively and connectably provided for an artery side passage 21 (pre-fluid replacement) or a venous side passage 22 (post fluid replacement) in a blood circuit 3. There are provided: a supply side pressure sensor S3 measuring pressure of a dialysis fluid supply passage 54; a collection side pressure sensor S4 measuring pressure of a dialysis fluid retrieval passage 55; and connection passages (24A, 24B, 25) one ends of which communicate with the artery side passage 21 or the venous side passage 22 of the blood circuit 3 and the other end of which are connected to the dialysis fluid retrieval passage 55. Moreover, it is determined in the state that a dialysate pump 63 (fluid sending means) has flown the dialysis fluid into the blood circuit 3 from the fluid replacement passage 27A whether the fluid replacement passage 27A is connected either to the artery side passage 21 or to the venous side passage 22 according to difference in pressure measured by the supply side pressure sensor S3 and the retrieval side pressure sensor S4.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a dialysis apparatus and a method for checking the connection of a replenishing fluid passage. More specifically, the present invention relates to a dialysis apparatus provided with a replenishing fluid passage for supplying a replenishing fluid to a blood circuit by supplying a dialysis fluid of a dialysis fluid circuit, and a method for checking the connection position of the replenishing fluid passage.

Background Art

[0002] A dialysis apparatus used in hemodialysis or the like includes a dialyzer for performing hemodialysis, a dialysis fluid supply passage for supplying fresh dialysis fluid to the dialyzer, a dialysis fluid recovery passage for recovering used dialysis fluid that has passed through the dialyzer, and a blood circuit including an arterial side passage for supplying blood to the dialyzer and a venous side passage for discharging blood from the dialyzer. In addition, in order to perform fluid replenishment to a patient during dialysis treatment, a dialysis apparatus provided with a replenishing fluid passage between the dialysis fluid supply passage and the blood circuit is known. Among these, there is also known a dialysis apparatus in which the replenishing fluid passage can be selectively connected to an arterial side passage or a venous side passage (Patent Document 1). Here, the case where the replenishing fluid passage is connected to the arterial side passage upstream of the dialyzer in the blood circuit to perform fluid replenishment is called pre-fluid replenishment (pre-dilution method), and the case where the replenishing fluid passage is connected to the venous side passage downstream of the dialyzer to perform fluid replenishment is called post-fluid replenishment (post-dilution method). The selection between these post-fluid replenishment or pre-fluid replenishment is determined by a doctor according to the patient's physical condition or the like. [[ID=!7]] However, since a dialysis apparatus is composed of many pipes as shown in FIG. 1, when a medical staff connects the replenishing fluid passage to an arterial side passage or a venous side passage according to a doctor's instruction, there is a risk of connection error. Therefore, in Patent Document 1, by flowing dialysis fluid toward a blood circuit that is not filled with liquid and detecting whether or not bubbles are detected by a bubble detector, it is determined whether the replenishing fluid passage is connected to the arterial side passage or the venous side passage.

Prior Art Documents

Patent Documents

[0003] [Patent Document 1] Patent No. 6900756 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In the above-mentioned Patent Document 1, one end of the arterial passage is connected to the other end of the venous passage, and air bubbles are detected by introducing liquid into the blood circuit from a state where these passages are not filled with fluid. Therefore, if a connection error in the fluid replacement passage is detected, attempting to use the detection method described in Patent Document 1 again after correcting the connection of the fluid replacement passage would require removing the fluid from the blood circuit, as the blood circuit would already be filled with fluid, resulting in a complicated procedure. Furthermore, it is difficult to completely remove liquid from the blood circuit, and the remaining liquid in the blood circuit may contain air bubbles. Therefore, there was a risk of false detections occurring if the above determination method were performed again. In view of these problems, the present invention provides a dialysis apparatus and a method for checking the connection of a fluid replacement passage that can determine the connection destination of the fluid replacement passage more simply and reliably. [Means for solving the problem]

[0005] That is, the dialysis apparatus according to claim 1 comprises a dialyzer for performing hemodialysis, a dialyzer supply passage for supplying fresh dialyzer fluid to the dialyzer, a dialyzer recovery passage for recovering used dialyzer fluid that has passed through the dialyzer, a blood circuit consisting of an arterial passage for supplying blood to the dialyzer and a venous passage for discharging blood from the dialyzer, a fluid replacement passage provided between the dialyzer supply passage and the blood circuit, and a fluid delivery means for delivering the dialyzer fluid from the dialyzer supply passage to the blood circuit via the fluid replacement passage. In a dialysis apparatus, the above-mentioned fluid replacement passage is provided so as to be selectively connectable to the arterial or venous passage of the blood circuit, The system comprises a supply-side pressure sensor for measuring the pressure of the liquid flowing through the dialysate supply passage, a recovery-side pressure sensor for measuring the pressure of the liquid flowing through the dialysate recovery passage, and a connecting passage having one end communicating with the arterial or venous passage of the blood circuit and the other end communicating with the dialysate recovery passage. Furthermore, the system is characterized by providing a determination means that, when the fluid delivery means causes the fluid to flow from the fluid replacement passage into the blood circuit and the fluid has flowed from the arterial or venous passage to the dialysate recovery passage via the connecting passage, determines whether the fluid replacement passage is connected to the arterial or venous passage based on the pressure difference between the pressure measured by the supply-side pressure sensor and the pressure measured by the recovery-side pressure sensor. Furthermore, the method for checking the connection of a fluid replacement passage according to claim 4 includes a dialyzer for performing hemodialysis, a dialyzer supply passage for supplying fresh dialyzer fluid to the dialyzer, a dialyzer recovery passage for recovering used dialyzer fluid that has passed through the dialyzer, a blood circuit consisting of an arterial passage for supplying blood to the dialyzer and a venous passage for draining blood from the dialyzer, a fluid replacement passage provided between the dialyzer supply passage and the blood circuit, and a fluid delivery means for delivering the dialyzer fluid from the dialyzer supply passage to the blood circuit via the fluid replacement passage. , control means for controlling the operation of the above-mentioned liquid delivery means and Equipped with, Before starting dialysis treatment, Whether the above fluid replacement passage is connected to the arterial or venous passage in the above blood circuit The above control means A method for checking the connection of the fluid replacement passage to be determined, A supply-side pressure sensor for measuring the pressure in the dialysate supply passage and a recovery-side pressure sensor for measuring the pressure in the dialysate recovery passage are provided. Either the arterial or venous passage of the blood circuit is connected to the dialysate recovery passage. In this state, the control means The above-mentioned liquid delivery means Activate it With the fluid flowing from the above-mentioned fluid replacement passage into the blood circuit, and the fluid circulating from the arterial or venous passage to the above-mentioned dialysate recovery passage, The above control means is The pressure difference between the pressure measured by the supply-side pressure sensor and the pressure measured by the recovery-side pressure sensor. Based on The system is characterized by determining whether the connection destination of the above-mentioned fluid replacement passage is the arterial passage or the venous passage. [Effects of the Invention]

[0006] According to the above invention, when the fluid delivery means causes the dialysate to flow into the blood circuit from the fluid replacement passage, the dialysate flows from the arterial side passage or the venous side passage through the connecting passage to the dialysate recovery passage. At this time, depending on the location where the fluid replacement passage is connected, the fluid may or may not pass through the dialyzer provided in the blood circuit. However, when the fluid passes through the dialyzer, pressure loss occurs as it passes through the numerous hollow fibers provided in the dialyzer. When the liquid passes through the dialyzer, a pressure difference is generated between the pressure measured by the supply-side pressure sensor and the pressure measured by the recovery-side pressure sensor. Therefore, it is possible to determine whether the fluid replacement passage is connected to the arterial or venous passage based on the magnitude of this pressure difference. [Brief explanation of the drawing]

[0007] [Figure 1] Front view of the dialysis apparatus according to the first embodiment. [Figure 2] Circuit diagram of a dialysis machine, specifically for use with post-fluid replacement. [Figure 3] Circuit diagram of a dialysis machine, specifically for use with post-fluid replacement. [Figure 4] Circuit diagram of a dialysis machine, specifically for use with pre-fluid replacement. [Figure 5] Circuit diagram of a dialysis machine, specifically for use with pre-fluid replacement. [Modes for carrying out the invention]

[0008] The following describes the illustrated embodiment. Figure 1 is a front view of the dialysis apparatus 1 according to this embodiment, and Figures 2 to 5 show the circuit diagram of the dialysis apparatus 1, particularly the state during the priming operation of the dialysis apparatus 1. The priming operation mentioned above refers to the operation of connecting the dialyzer 2 and the blood circuit 3 to the dialysis device 1 before performing dialysis treatment and filling the dialyzer 2 and the blood circuit 3 with dialysate. In addition, in the dialysis device 1 of this embodiment, it is possible to replenish the patient with dialysate during dialysis treatment. As such replenishment, it is possible to selectively perform post-replenishment by connecting the replenishment passage shown in FIGS. 2 and 3 to the venous-side passage of the blood circuit 3 and pre-replenishment by connecting it to the arterial-side passage shown in FIGS. 4 and 5. These post-replenishment and pre-replenishment are instructed by the doctor according to the patient's physical condition, etc. However, since medical staff connect the replenishment passage, it was necessary to prevent connection errors. Therefore, the dialysis device 1 of this embodiment determines whether the replenishment passage is connected to either the venous-side passage or the arterial-side passage of the blood circuit 3 in parallel with the priming operation, so that it can be confirmed whether the connection is made as instructed by the doctor.

[0009] The dialysis device 1 includes a dialyzer 2 for performing hemodialysis, a blood circuit 3 for circulating blood through the dialyzer 2, and a dialysate circuit 4 for circulating dialysate through the dialyzer 2, and is controlled by a control means 5 composed of a computer such as a microcomputer or a personal computer. In FIG. 1, most of the dialyzer 2 and the blood circuit 3 are provided so as to be exposed on the front surface of the main body 6 constituting the dialysis device 1. On the other hand, most of the dialysate circuit 4 is housed inside the dialysis device 1. On the upper part of the main body 6, a touch panel 5a constituting the control means 5 for displaying the state of the patient during dialysis treatment and performing necessary operations is provided, and a dialyzer holder 7 for holding the dialyzer 2 is provided on the side surface. In addition, a blood pump 8 for sending the blood in the blood circuit 3 is provided on the front surface of the main body 6, and at the same time, a drip chamber 9 constituting the blood circuit 3 and a syringe 10 for drug injection are held.

[0010] Furthermore, on the front surface of the main body 6, there are provided first to third connection ports P1 to P3 for connecting the blood circuit 3 and the dialysate circuit 4, and first and second sensor ports P4 and P5 for connecting a part of the piping of the blood circuit 3 to measure the pressure of the blood circuit 3. These connection ports P can use, for example, the configuration described in Japanese Patent No. 5920575, and are composed of a connector provided at the end of the piping constituting the dialysate circuit 4 and a lid member rotatably provided on the front surface of the main body 6. With such a configuration, for example, during the priming operation, the lid member is rotated to expose the connector to the outside, the piping of the blood circuit 3 is connected, and during the dialysis operation, the piping is removed and the connector can be covered so as not to be exposed to the outside.

[0011] The dialyzer 2 includes innumerable hollow fibers inside a resin cylindrical portion, and the inside of the hollow fibers forms a blood chamber 2a through which blood flows, and the outside of the hollow fibers forms a dialysate chamber 2b through which dialysate flows. Caps are provided at both ends of the dialyzer 2. The blood circuit 3 is connected to the center of the cap and communicates with the blood chamber 2a, and the dialysate circuit 4 is connected to the side portion of the cap and communicates with the dialysate chamber 2b. As shown in FIG. 1, the dialyzer 2 is held by the dialyzer holder 7 so that the caps are positioned vertically. During dialysis treatment, blood flows through the blood chamber 2a from above to below (from left to right in FIG. 2), and dialysate flows through the dialysate chamber 2b from below to above (from right to left in FIG. 2).

[0012] The blood circuit 3 includes an arterial side passage 21 for sending blood from the patient's artery to the blood chamber 2a of the dialyzer 2 and a venous side passage 22 for returning blood from the blood chamber 2a to the patient's vein. In FIG. 1, the arterial side passage 21 is connected to the upper part of the dialyzer 2, and the venous side passage22 is connected to the lower part of the dialyzer 2. In Figure 2, the end of the arterial passage 21 is provided with a connector 21a to which a puncture needle is attached during treatment. Starting from a position adjacent to the connector 21a, the following are provided in order: an arterial clamp V1, a blood return passage 23A for returning blood to the patient after dialysis treatment, an arterial pressure sensor S1 for measuring the pressure in the arterial passage 21, a syringe 10 for introducing medication into the blood circuit 3, and a pre-infusion connector C1 for connecting the infusion passage when performing pre-infusion.

[0013] In the dialysis machine 1 during priming, one end of the first priming pipe 24A, which serves as a connecting passage, is connected to the connector 21a of the arterial passage 21, and the other end of the first priming pipe 24A is connected to the third connecting port P3 provided at the end of the connecting passage 24B that constitutes the dialysate circuit 4. The arterial clamp V1 is housed in a case 6a located on the front of the main body 6, and the arterial passage 21 is automatically opened and closed by a drive mechanism (not shown) controlled by the control means 5.

[0014] The blood return passage 23A described above is used to return blood from the blood circuit 3 to the patient after dialysis treatment. A check valve B is provided near the branching point with the arterial passage 21, which is the base of the passage, and the tip is connected to a first connection port P1 provided at the end of the blood return passage 23B that constitutes the dialysate circuit 4. A second priming pipe 25 is branched off from the blood return passage 23A as a connecting passage used during priming, and is connected to the connector 22a at the end of the venous passage 22 during priming. The second priming pipe 25 can also be closed by a manual clamp 26.

[0015] In Figure 1, the arterial pressure sensor S1 is equipped with a first sensor port P4 on the front of the main body 6, and is used by connecting a pipe branched from the arterial passage 21 to the first sensor port P4. The blood pump 8 described above is composed of a so-called tubular pump, and by compressing the piping that constitutes the arterial passage 21 as the rotor rotates, it pumps fluid by pushing out the fluid inside the piping. During priming as shown in Figures 2 and 4, when filling the arterial passage 21 with dialysate, the arterial passage 21 is not attached to the blood pump 8 to avoid obstructing the flow of fluid in the arterial passage 21. The syringe 10 contains a drug, and the plunger is advanced by a pressing means controlled by the control means 5, so that during dialysis treatment, the drug is automatically supplied from the syringe 10 to the blood circuit 3.

[0016] As shown in Figures 4 and 5, the pre-fluid replacement connector C1 is connected to the fluid replacement passage 27A when pre-fluid replacement is performed, and connectors are provided at both ends of the fluid replacement passage 27A. One connector of the fluid replacement passage 27A is connected to a second connection port P2 provided at the end of the fluid replacement passage 27B that constitutes the dialysate circuit 4, and the other connector is connected to either the pre-fluid replacement connector C1 or the post-fluid replacement connector C2, which will be described later, provided on the venous passage 22. The pre-fluid replacement connector C1 is located at a position branching off from the arterial passage 21, and a check valve B is provided between the pre-fluid replacement connector C1 and the arterial passage 21 to prevent backflow from the blood circuit 4.

[0017] The venous passage 22 described above is connected to the lower end of the dialyzer 2 in Figure 1, and a connector 22a is provided at its end to which a puncture needle is attached during dialysis treatment. The venous passage 22 is provided with, in order from the dialyzer 2 side, a post-infusion connector C2 to which the infusion passage 27A is connected when post-infusion is performed, the drip chamber 9, and a venous clamp V2. As shown in Figures 2 and 3, the post-fluid replacement connector C2 is connected to the fluid replacement passage 27A when post-fluid replacement is performed. Furthermore, the post-fluid replacement connector C2 has the same structure as the pre-fluid replacement connector C1, and a check valve B provided between the post-fluid replacement connector C2 and the venous passage 22 prevents backflow from the blood circuit 4.

[0018] As shown in Figure 1, the drip chamber 9 comprises a cylindrical container and a cap held in front of the main body 6 of the dialysis machine 1, and a venous pressure sensor S2 for measuring the pressure in the venous passage 22 is connected to the cap. In Figure 1, the venous pressure sensor S2 is equipped with a second sensor port P5 on the front of the main body 6, and is used by connecting the piping branched from the venous passage 22 to the second sensor port P5.

[0019] The dialysate circuit 4 includes first and second dialysate chambers 51 and 52, each having supply chambers 51a and 52a and recovery chambers 51b and 52b formed inside by a diaphragm; a supply passage 53 for supplying dialysate to the supply chambers 51a and 52a; a dialysate supply passage 54 for supplying fresh dialysate from the supply chambers 51a and 52a to the dialyzer 2; a dialysate recovery passage 55 for recovering used dialysate from the dialyzer 2 to the recovery chambers 51b and 52b; and a drainage passage 56 for discharging used dialysate from the recovery chambers 51b and 52b. The above-mentioned liquid supply passage 53 has its upstream end connected to a water source (not shown) that supplies clean water. Starting from the upstream side of the water source, it is equipped with a water supply valve V4 controlled by a control means 5, a first bypass passage 57 that communicates with the above-mentioned drain passage 56, a liquid supply pump 58 that delivers clean water from the water source, and a dialysate concentrate supply means 59 that supplies the dialysate concentrate. The downstream end of the fluid supply passage 53 branches out toward the first and second dialysate chambers 51 and 52, and the branched passages are equipped with fluid supply valves V5 and V6, respectively, which are controlled by the control means 5.

[0020] The first bypass passage 57 is provided to branch off upstream of the liquid supply pump 58, and the other end is connected to the drain passage 56. In the middle of the first bypass passage 57, there is a seventh on-off valve V7 controlled by the control means 5, and a second bypass passage 60 that branches off upstream of the seventh on-off valve V7. The other end of the second bypass passage 60 is connected to the drain passage 56, and the second bypass passage 60 is provided with an eighth on-off valve V8 controlled by the control means 5.

[0021] The above-mentioned dialysis fluid concentrate supply means 59 includes a concentrate tank (not shown) that contains concentrates A and B, which are raw materials for the dialysis fluid, and a liquid pump that supplies predetermined amounts of concentrates A and B from the concentrate tank. The A and B concentrates delivered by the above-mentioned liquid delivery pumps flow through the supply passage 53 together with the purified water delivered by the above-mentioned supply pump 58, and flow into the supply chambers 51a and 52a of the first and second dialysate chambers 51 and 52. These stock solutions A and B are mixed with purified water inside the supply chambers 51a and 52a, as well as inside the two filters CF1 and CF2 described later, thereby preparing a dialysate of a predetermined concentration.

[0022] The upstream portion of the dialysate supply passage 54 branches into two directions, each connected to the supply chambers 51a and 52a of the first and second dialysate chambers 51 and 52, respectively. The downstream end is connected to the lower end of the dialyzer 2 in Figure 1, and communicates with the dialysate chamber 2b. Furthermore, supply valves V9 and V10 are provided at the branching portions of the dialysate supply passage 54, and downstream of the branching portions, in order from the upstream side, are provided: two filters CF1 and CF2 for adsorbing endotoxins and other substances in the dialysate; a supply-side pressure sensor S3 for measuring the pressure of the dialysate flowing through the dialysate supply passage 54; a first flow rate throttling means MV1; a flow meter FM1 for measuring the flow rate of liquids such as dialysate flowing through the dialysate supply passage 54; a replacement fluid passage 27B to which the replacement fluid passage 27A is connected; a blood return passage 23B to which the blood return passage 23A is connected; a third bypass passage 61 provided between the replacement fluid passage 61 and the dialysate recovery passage 55; and an eleventh on / off valve V11 controlled by the control means 5.

[0023] The fluid replacement passage 27B is provided so as to branch off from the dialysate supply passage 54 at a position downstream of the supply-side pressure sensor S4, and the fluid replacement passage 27B is provided with a second flow rate throttling means MV2 and a 12th on / off valve V12 controlled by the control means 5. Furthermore, a second connection port P2 is provided at the end of the fluid replacement passage 27B, which is located on the front of the main body 6 in Figure 1, and as described above, the connector of the fluid replacement passage 27A is connected to it. During dialysis treatment, when administering fluids, the dialysis fluid from the dialysis fluid supply passage 54 is supplied to the arterial passage 21 or venous passage 22 of the blood circuit 3 via the fluid replacement passages 27B and 27A to provide fluid replacement to the patient. In this process, the control means 5 adjusts the opening of the first flow throttling means MV1 and the second flow throttling means MV2 so that the required amount of dialysate is supplied to the blood circuit 3. Such control is described in, for example, Japanese Patent Application Publication No. 2021-062067 and is therefore publicly known.

[0024] The blood return passage 23B is provided by branching off from the dialysate supply passage 54 at a position downstream of the fluid replacement passage 27B, and is equipped with a 13th on / off valve V13 controlled by the control means 5. Furthermore, the end of the blood return passage 23B is provided with the first connection port P1, which is located on the front of the main body 6 in Figure 1, and the blood return passage 23, which is branched off from the arterial passage 21 of the blood circuit 3, is connected to it. When returning the blood from the blood circuit 3 to the patient after dialysis treatment, the 13th on-off valve V13 is opened to allow fresh dialysis fluid to flow from the dialysis fluid supply passage 54 to the blood circuit 3 via the blood return passage 23, and the dialysis fluid pushes the blood in the blood circuit 3 back to the patient.

[0025] The third bypass passage 61 described above branches off downstream of the blood return passage 23B and is connected to the dialysate recovery passage 55, and is equipped with a 14th on-off valve V14 and a 15th on-off valve V15 controlled by the control means 5. Between the 14th on-off valve V14 and the 15th on-off valve in the third bypass passage 61, the above-mentioned connecting passage 24B is provided, and the 16th on-off valve V16, which is controlled by the control means 5, is provided in the connecting passage 24B. The end of the above-mentioned connection passage 24B is provided with the third connection port P3, which is located on the front of the main body 6 in Figure 1, and the first priming pipe 24A, which is connected to the arterial side passage 21 of the blood circuit 3, is connected to it.

[0026] The dialysate recovery passage 55 described above has its upstream end connected to the dialyzer 2, and in Figure 1 it is connected to the upper side of the diagram. Starting from the dialyzer 2 side, it is equipped with a 17th on / off valve V17 controlled by a control means 5, a recovery-side pressure sensor S4 for measuring the pressure of the dialysate in the dialysate recovery passage 55, an aeration tank 62 for removing air bubbles from the dialysate, a first bypass passage 57 that communicates with the fluid supply passage 53, a dialysate pump 63 as a fluid delivery means for delivering dialysate, and a water removal passage 64 for removing water during treatment. Furthermore, the downstream end of the dialysate recovery passage 55 branches in two directions, each connected to the recovery chambers 51b and 52b of the first and second dialysate chambers 51 and 52, respectively, and recovery valves V18 and V19 are provided at the branching portion.

[0027] The aeration tank 62 is provided with an exhaust passage 65, the other end of which is connected to the drainage passage 56, and the exhaust passage 65 is provided with a 20th on / off valve V20 controlled by the control means 5. The above-mentioned aeration tank 62 is conventionally known and, when used dialysate flows in during dialysis treatment, separates the gas contained in the used dialysate and discharges it through the exhaust passage 65 and the drain passage 56. The first bypass passage 57 is connected between the aeration tank 62 and the dialysate pump 63, and is used to replenish the dialysate recovery passage 55 with the purified water from the supply passage 53 during priming operations.

[0028] The above-mentioned water removal passage 64 is connected to the downstream side of the dialysate pump 63, and a water removal pump 66 is provided in the water removal passage 64. A second fluid supply passage 67 is provided between the water removal pump 66 and the dialysate concentrate supply means 59, and a 21st on-off valve V21 controlled by a control means is provided in the second fluid supply passage. During dialysis treatment, activating the above-mentioned water removal pump 66 creates a pressure difference between the dialysate chamber 2b and the blood chamber 2a in the dialyzer 2, thereby moving and removing water from the blood through the hollow fiber membrane to the dialysate circuit 4. In this invention, the water removal pump 66 can also be used as a fluid delivery means. In this case, clean water is supplied via the second fluid supply passage 67, and after this clean water flows through the water removal passage 64, it flows through the dialysate recovery passage 55 and flows into the recovery chambers 51b and 52b of the first and second dialysate chambers 51 and 52. As a result, the volume of the recovery chamber 51b gradually expands, and consequently the volumes of the supply chambers 51a and 52a decrease, allowing the dialysate to be discharged from the supply chambers 51a and 52a into the dialysate supply passage 54.

[0029] The drainage passage 56 described above branches in two directions at its upstream end, each connected to the recovery chambers 51b and 52b of the first and second dialysate chambers 51 and 52, respectively, and drainage valves V22 and V23 are provided at the branching portion. Furthermore, the drainage passage 56 is provided with a water removal passage 64 that communicates with the dialysate recovery passage 55, an exhaust passage 65 that communicates with the aeration tank 62 of the dialysate recovery passage 55, a 24th on-off valve V24 controlled by the control means 5, and a second bypass passage 60 connected to the first bypass passage 57.

[0030] The following describes a method for determining whether the fluid replacement passage 27A is connected to either post-fluid replacement or pre-fluid replacement, simultaneously with priming, using the dialysis apparatus 1 having the above configuration. The priming operation described below represents only a part of the overall priming operation, and the operation described below is merely an example. It is also possible to perform priming and connection determination of the fluid supply passage 27A using other operations with the above configuration. Furthermore, in Figures 2 and below, the parts through which dialysate (or purified water) flows are shown with thick lines. However, regarding the flow of dialysate in dialysate circuit 4, the flow of dialysate associated with normal operation, such as during dialysis treatment, is not shown with thick lines, while the flow of liquid generated during the priming process is shown with thick lines. Furthermore, unless otherwise specified, in the diagrams, black indicates the closed state of each valve and clamp, while white indicates the open state.

[0031] First, using Figures 2 and 3, we will explain the operation when the fluid replacement passage 27A is connected in accordance with post-fluid replacement. In this case, the fluid replacement passage 27A is connected to the post-fluid replacement connector C2 of the venous passage 22 of the blood circuit 3. First, as shown in Figure 2, the dialyzer 2 and blood circuit 3 are attached to the dialysis machine 1. However, the arterial passage 21 is not attached to the blood pump 8, so as not to obstruct the flow of fluid in the arterial passage 21. The blood return passage 23A of the blood circuit 3 is connected to the blood return passage 23B of the dialysate circuit 4 via the first connection port P1. Furthermore, the connector 21a of the arterial passage 21 of the blood circuit 3 is connected to the first priming pipe 24A, which in turn is connected to the third connection port P3 of the connection passage 24B that constitutes the dialysate circuit 4. Furthermore, a second priming pipe 25, which branches off from the blood return passage 23B, is connected to the connector 22a of the venous passage 22 of the blood circuit 3, and the manual clamp 26 of the second priming pipe 25 is in an open state.

[0032] With the fluid infusion passage 27A connected to the venous passage 22 corresponding to post-fluid infusion, the healthcare professional operates the touch panel 5a to instruct the start of the priming procedure. In the following explanation, the description of the dialysate delivery operation in the dialysate circuit 4 will be omitted. However, the state shown in Figure 2 is that the dialysate has already been prepared in the supply chamber 51a of the first dialysate chamber 51, and the supply valve V9 and the recovery valve V18 of the recovery chamber 51b are open. In the above-mentioned fluid supply passage 53, the water supply valve V4 is open, the fluid supply valve V5 to the supply chamber 51a of the first dialysate chamber 51 is closed, and the seventh on / off valve V7 of the first bypass passage 57, which is provided between the fluid supply passage 53 and the dialysate recovery passage 55, is open. As a result, when the dialysate pump 63 in the dialysate recovery passage 55 delivers fluid, the clean water in the fluid supply passage 53 flows through the first bypass passage 57 and then flows into the recovery chamber 51b of the first dialysate chamber 51. As a result, the volume of the recovery chamber 51b gradually expands, and consequently the volume of the supply chamber 51a decreases, causing the dialysate to be discharged from the supply chamber 51a into the dialysate supply passage 54.

[0033] The discharged dialysate flows through the dialysate supply passage 54. At this time, the 11th on-off valve V11 of the dialysate supply passage 54, the 13th on-off valve V13 of the blood return passage 23B, and the 14th on-off valve V14 of the third bypass passage 61 are closed, so the dialysate flows from the dialysate supply passage 54 to the replacement fluid passage 27B. Furthermore, the fluid replacement passage 27A is connected to the fluid replacement passage 27B, and to accommodate post-fluid replacement, the fluid replacement passage 27A is connected to the post-fluid replacement connector C2 of the venous passage 22. Therefore, the dialysate that has flowed through the replacement fluid passage 27B will flow into the venous passage 22 via the post-replacement fluid connector C2. On the other hand, in the blood circuit 3, the arterial clamp V1 of the arterial passage 21 is open, and the venous clamp V2 of the venous passage 22 is closed. Therefore, the dialysate that flows into the venous passage 22 flows upstream from the post-replenishment connector C, which is the opposite direction to the flow during dialysis treatment. After passing through the inside of the dialysate 2, the dialysate then flows through the arterial passage 21. As a result, the inside of the arterial passage 21 is filled with dialysate, and the priming of the arterial passage 21 can be completed.

[0034] The dialysate that has flowed through the arterial passage 21 then flows through the first priming pipe 24A before flowing into the connecting passage 24B provided in the dialysate circuit 4. In the dialysate circuit 4, the 17th on-off valve V17 of the dialysate recovery passage 55 is closed, the 15th on-off valve V15 of the third bypass passage 61 is open, and the 20th on-off valve V20 of the exhaust passage 65 connected to the aeration tank 62 is open. As a result, the dialysate flows from the first priming pipe 24A through the connecting passage 24B to the third bypass passage 61, then flows through the dialysate recovery passage 55 and into the aeration tank 62, where it flows through the exhaust passage 65 and is then discharged from the drain passage 56.

[0035] During the above operation, the control means 5 measures the pressure of the circulating dialysis fluid using the supply-side pressure sensor S3 installed in the dialysis fluid supply passage 54 and the recovery-side pressure sensor S4 installed in the dialysis fluid recovery passage 55. As described above, in the state shown in Figure 2, the fluid replacement passage 27A is connected to the venous passage 22 in accordance with post-fluid replacement, and since the dialysate flows in the reverse direction to that during dialysis treatment, the dialysate passes through the dialyzer 2 from the venous passage 22 and is then discharged from the arterial passage 21. As the dialysate passes through the dialyzer 2, pressure loss occurs as it passes through the hollow fibers provided in the dialyzer 2. Therefore, the pressure measured by the recovery-side pressure sensor S4, located downstream of the dialyzer 2, is lower than the pressure measured by the supply-side pressure sensor S3, located upstream of the dialyzer 2. Furthermore, since the venous clamp V2 in the blood circuit 3 is closed, the control means 5 recognizes that the dialysate is flowing through the blood circuit 3 in the opposite direction to that during dialysis treatment. In this state, that is, when the dialysate is flowing in the reverse direction, if the differential pressure Δ1 between the pressure measured by the supply-side pressure sensor S3 and the pressure measured by the recovery-side pressure sensor S4 exceeds the first threshold described below, the control means 5 determines that the dialysate is flowing through the dialyzer 2 and determines that the replacement fluid passage 27A is connected to the venous passage 22, i.e., post-replacement fluid.

[0036] Once the priming of the arterial passage 21 shown in Figure 2 is complete, the control means 5 then starts the priming operation of the venous passage 22 as shown in Figure 3. The control means 5 opens the venous clamp V2 of the venous passage 22 and attaches the arterial passage 21 to the blood pump 8, thereby occluding the arterial passage 21 with the blood pump 8. It also keeps the manual clamp 26 of the second priming pipe 25 connected to the venous passage 22 open. In this state, if dialysate is introduced into the blood circuit 3 from the infusion passage 27A as shown in Figure 2, the dialysate will flow in from the post-infusion connector C2 provided in the venous passage 22 and will circulate in the same forward direction as during dialysis treatment. As the dialysate flows through the venous passage 22, the portion downstream of the post-replenishment connector C2 is filled with dialysate, and since the priming of the portion upstream of the post-replenishment connector C2 is completed in the operation shown in Figure 2, the priming of the venous passage 22 is completed. The dialysis fluid that has flowed through the venous passage 22 then flows through the second priming pipe 25, passes through a portion of the blood return passage 23B, flows into the arterial passage 21, then flows through the first priming pipe 24A, flows through the dialysis fluid recovery passage 55, and is then drained from the drainage passage 56. In other words, even in the state shown in Figure 3, the venous passage 22 is in communication with the dialysate recovery passage 55 via the first priming pipe 24 and the second priming pipe 25, as well as the connecting passage 24B.

[0037] In the operation shown in Figure 3, the dialysate flows only through the venous passage 22 and is discharged to the dialysate recovery passage 55. Therefore, the dialysate does not pass through the dialyzer 2, and thus, unlike priming in the arterial passage 21, no pressure loss occurs due to the dialyzer 2. On the other hand, the dialysate passes through a drip chamber 9 provided in the venous passage 22 and a check valve B provided in the blood return passage 23A, which is into which the dialysate flows via the second priming pipe 25, resulting in pressure loss. However, this pressure loss is lower than the pressure loss caused by passing through the dialyzer 2. Then, when the dialysate is flowing in the forward direction, if the differential pressure Δ2 does not exceed the second threshold described below, the control means 5 determines that the dialysate is not flowing through the dialyzer 2 and that the replacement fluid passage 27A is a connection corresponding to the venous passage 22, i.e., post-replacement fluid.

[0038] Here, we will explain the case where, despite instructions for post-fluid replacement, the fluid replacement passage 27A was mistakenly connected to the pre-fluid replacement connector C1 of the arterial passage 21, as shown in Figures 4 and 5. First, in Figure 4, which corresponds to Figure 2, the dialysate flows in from the replacement fluid passage 27A through the pre-replacement fluid connector C1 provided in the arterial side passage 21, and then flows in the opposite direction to that during dialysis treatment. Since the dialysate flows in from the arterial passage 21 and is discharged from the first priming pipe 24A without passing through the dialyzer 2, the pressure loss that would occur due to passing through the dialyzer 2 as described above does not occur. Therefore, the pressure difference Δ3 between the pressure measured by the supply-side pressure sensor S3 and the pressure measured by the recovery-side pressure sensor S4 will be smaller than in the case of a connection corresponding to post-replenishment, and will not exceed the first threshold mentioned above. In other words, when the dialysis fluid is flowing in the reverse direction, if the differential pressure Δ3 does not exceed the first threshold, the control means 5 determines that the fluid replacement passage 27A is connected to the arterial passage 21, i.e., to the pre-fluid replacement passage, and displays a warning on the touch panel 5a or the like indicating that there is a connection error.

[0039] Furthermore, this type of connection check can also be performed when the dialysate is flowing in the same forward direction as during dialysis treatment, as shown in Figure 5. In other words, when the dialysate flows in from the pre-replenishment connector C1 provided in the arterial passage 21 and flows in the same forward direction as during dialysis treatment, pressure loss occurs as the dialysate passes through the dialyzer 2, then through the drip chamber 9 of the venous passage 22 and the second priming pipe 25, and then through the check valve B of the blood return passage 23A. As a result, the pressure difference Δ4 between the pressure measured by the supply-side pressure sensor S3 and the pressure measured by the recovery-side pressure sensor S4 exceeds the second threshold. Therefore, when the dialysis fluid is flowing in the forward direction, if the differential pressure Δ4 exceeds the second threshold, the control means 5 can determine that the fluid replacement passage 27A is connected to the arterial passage 21, i.e., the pre-fluid replacement passage.

[0040] Next, using Figures 4 and 5, we will explain the operation when the fluid replacement passage 27A is connected in accordance with pre-fluid replacement. In this case, compared to the state shown in Figures 2 and 3, the fluid replacement passage 27A is connected to the pre-fluid replacement connector C1 of the arterial passage 21. When the priming process is initiated from this state, the dialysate discharged from the supply chamber 51a of the first dialysate chamber 51 of the dialysate circuit 4 flows from the dialysate supply passage 54 to the replacement fluid passage 27A. In the state shown in Figure 4, the arterial clamp V1 of the arterial passage 21 is open, and the venous clamp V2 of the venous passage 22 is closed in the blood circuit 3. As a result, the dialysate that flows from the infusion passage 27A to the arterial passage 21 via the pre-infusion connector C1 flows in the opposite direction to that during dialysis treatment, flows through the first priming pipe 24A, then through the dialysate recovery passage 55, flows through the exhaust passage 65 from the aeration tank 62, and is then discharged from the drain passage 56. In this way, by circulating the dialysate in the reverse direction compared to normal dialysis treatment, the portion of the arterial passage 21 in the blood circuit 3 upstream of the pre-replenishment connector C1 can be filled with dialysate.

[0041] Meanwhile, during the above operation, the control means 5 measures the pressure of the circulating dialysis fluid using the supply-side pressure sensor S3 installed in the dialysis fluid supply passage 54 and the recovery-side pressure sensor S4 installed in the dialysis fluid recovery passage 55. Here, as described above, in the state shown in Figure 4, the fluid replacement passage 27A is provided in the arterial passage 21 corresponding to the pre-fluid replacement, and since the dialysate flows in the opposite direction to that during dialysis treatment, the dialysate flows in from the arterial passage 21 and is discharged from the arterial passage 21 without passing through the dialyzer 2. Therefore, no pressure loss occurs when the dialysate passes through the dialyzer 2, and as shown in Figure 3, no pressure loss occurs due to the drip chamber 9 or check valve B. From the above, as shown in Figure 4, the replacement fluid passage 27A is connected in accordance with the pre-replacement fluid, and when the dialysate flows in the reverse direction, the differential pressure Δ3 between the pressure measured by the supply-side pressure sensor S3 located upstream of the dialyzer 2 and the pressure measured by the recovery-side pressure sensor S4 located downstream of the dialyzer 2 becomes small. The control means 5 determines that the fluid replacement passage 27A is connected to the arterial passage 21, i.e., the pre-fluid replacement passage, if the differential pressure Δ3 between the pressure measured by the supply-side pressure sensor S3 and the pressure measured by the recovery-side pressure sensor S4 does not exceed the first threshold used in the state shown in Figure 2.

[0042] In this way, the dialysate is discharged from the infusion passage 27A connected to the arterial passage 21 in response to the pre-infusion, and once the priming of the arterial passage 21 is complete, the dialysate is then circulated in the same forward direction as during dialysis treatment, as shown in Figure 5. In this case, the control means 5 opens the venous clamp V2 of the venous passage 22 and attaches the arterial passage 21 to the blood pump 8, thereby occluding the arterial passage 21 with the blood pump 8. The manual clamp 26 of the second priming pipe 25 connected to the venous passage 22 is also left open. In this state, when dialysate is introduced into the blood circuit 3 via the infusion passage 27A, the dialysate that flows in from the pre-infusion connector C1 of the arterial passage 21 will flow through the arterial passage 21 in the same forward direction as during dialysis treatment. After passing through the dialyzer 2, the dialysate flows through the venous passage 22, then through the second priming pipe 25 and a portion of the arterial passage 21, then through the first priming pipe 24A, and is subsequently drained from the dialysate recovery passage 55 through the drainage passage 56. In the operation shown in Figure 5, pressure loss occurs as the dialysate passes through the dialyzer 2, as well as through the drip chamber 9 of the venous passage 22 and the check valve of the blood return passage 23A. Therefore, when the dialysate is flowing in the forward direction, if the differential pressure Δ4 between the pressure measured by the supply-side pressure sensor S3 and the pressure measured by the recovery-side pressure sensor S4 exceeds the second threshold used in Figure 3, the control means 5 determines that the dialysate has flowed through the dialyzer 2 and determines that the replacement fluid passage 27A is connected to the arterial-side passage 21, i.e., the pre-replacement fluid passage.

[0043] Here, we will explain the operation when, due to a connection error, the fluid replacement passage 27A is connected to the post-fluid replacement connector C2 of the venous passage 22. When the dialysis fluid is circulated in the reverse direction with the replenishment fluid passage 27A connected to the post-replenishment fluid connector C2, a pressure loss occurs as the fluid passes through the dialyzer 2, as shown in Figure 2, and the differential pressure Δ1 is measured as explained in Figure 2. Furthermore, since the differential pressure Δ1 exceeds the first threshold, the control means 5 can recognize that there is a connection error. Similarly, when the dialysis fluid is flowed forward with the fluid replacement passage 27A connected to the post-fluid replacement connector C2, the dialysis fluid flows in from the venous passage 22 and is discharged without passing through the dialyzer 2, as shown in Figure 3. As a result, the differential pressure Δ2 described in Figure 3 is measured. Furthermore, since the differential pressure Δ2 does not exceed the second threshold, the control means 5 can recognize that there is a connection error.

[0044] The following explains how to set the first and second thresholds mentioned above. First, regarding the first threshold, as shown in Figure 2, the fluid replacement passage 27A is connected to the post-fluid replacement connector C2 of the venous passage 22 in response to the post-fluid replacement, and the dialysate is circulated in the reverse direction. Then, the differential pressure Δ1 between the pressure measured by the supply-side pressure sensor S3 and the pressure measured by the recovery-side pressure sensor S4 is measured. Next, as shown in Figure 4, the fluid replacement passage 27A is connected to the pre-fluid replacement connector C2 of the arterial passage 21 to allow the dialysate to flow in the reverse direction. Then, the differential pressure Δ3 between the pressure measured by the supply-side pressure sensor S3 and the pressure measured by the recovery-side pressure sensor S4 is measured. In this way, the value between the differential pressure Δ1 and the differential pressure Δ3 can be set as the first threshold value. For example, the midpoint between the differential pressure Δ1 and the differential pressure Δ3 can be set as the first threshold value.

[0045] Similarly, for the second threshold, as shown in Figure 3, the fluid replacement passage 27A is connected to the post-fluid replacement connector C2 of the venous passage 22 in correspondence with post-fluid replacement, and the dialysate is allowed to flow in the forward direction. Then, the differential pressure Δ2 between the pressure measured by the supply-side pressure sensor S3 and the pressure measured by the recovery-side pressure sensor S4 is measured. Next, as shown in Figure 5, the fluid replacement passage 27A is connected to the pre-fluid replacement connector C2 of the arterial passage 21 to allow the dialysate to flow in the forward direction. Then, the differential pressure Δ4 between the pressure measured by the supply-side pressure sensor S3 and the pressure measured by the recovery-side pressure sensor S4 is measured. In this way, the value between the differential pressure Δ2 and the differential pressure Δ4 can be used as the second threshold. For example, the midpoint between the differential pressure Δ2 and the differential pressure Δ4 can be used as the second threshold.

[0046] Here, as shown in Figures 2 and 4, when the dialysate was circulated in the reverse direction, in the connection corresponding to post-replenishment fluid in Figure 2, the dialysate passed through dialyzer 2, and when the differential pressure Δ1 at this time was actually measured, it was found to be Δ1 = 45 kPa. In contrast, with the connection corresponding to the pre-replenishment fluid in Figure 3, the dialysate did not pass through dialyzer 2, and when the differential pressure Δ3 was measured at this time, it was found to be Δ3 = 40 kPa. Therefore, the difference between these differential pressures Δ1 and Δ3 is 5 kPa, and the intermediate value of 42.5 kPa, which is the midpoint between these two, can be set as the first threshold. However, the difference between differential pressure Δ1 and differential pressure Δ3 is only 5 kPa, and therefore, depending on the measurement conditions of the supply-side pressure sensor S3 and the recovery-side pressure sensor S4 (such as the routing of the blood circuit), there may be cases where only 42 kPa of differential pressure Δ1 is detected in the state shown in Figure 2. In that case, since the differential pressure Δ1 falls below the first threshold, the control means 5 will determine that the fluid replacement passage 27A is not connected to support post-fluid replacement, resulting in a misjudgment. This is also true when the dialysate is circulated in the forward direction. In fact, measurements based on the piping in Figure 3 showed a differential pressure of Δ2 = 60 kPa, and measurements based on the piping in Figure 5 showed a differential pressure of Δ4 = 65 kPa. This indicates that the difference between differential pressure Δ2 and differential pressure Δ4 is ​​only 5 kPa.

[0047] Therefore, in order to perform a more accurate connection check of the fluid replacement passage 27A, it is possible to perform a connection check using the third threshold described below. As shown in Figures 2 and 3, with the fluid replacement passage 27A connected in accordance with post-fluid replacement, the difference between the differential pressure Δ3 = 45 kPa when the dialysate is circulated in the reverse direction as shown in Figure 2 and the differential pressure Δ4 = 60 kPa when it is circulated in the forward direction is Δpost = 15 kPa (absolute value). In contrast, as shown in Figures 4 and 5, with the replacement fluid passage 27A connected to correspond to the pre-replacement fluid, the difference between the differential pressure Δ1 = 40 kPa when the dialysate shown in Figure 4 is circulated in the reverse direction and the differential pressure Δ2 = 65 kPa when it is circulated in the forward direction is Δpre = 25 kPa (absolute value). Furthermore, the difference between Δpost = 15kPa when corresponding to post-fluid replacement and Δpre = 25kPa when corresponding to pre-fluid replacement is 10kPa, which is larger than the difference between differential pressure Δ1 and differential pressure Δ3, and the difference between differential pressure Δ2 and differential pressure Δ4 mentioned above. Furthermore, 20 kPa, which is the midpoint between Δpost and Δpre, can be used as the third threshold. In this case, Δpost, which corresponds to post-infusion, will be lower than the above third threshold, and Δpre, which corresponds to pre-infusion, will be higher than the above third threshold. The third threshold, with a difference of 10 kPa between Δpost and Δpre, offers a wider tolerance for measurement error than the first and second thresholds mentioned above, allowing for more reliable connection checks.

[0048] The following explains how to actually perform a connection check using the third threshold. First, we will explain the case where the fluid replacement passage 27A is connected to the post-fluid replacement connector C2, corresponding to the post-fluid replacement shown in Figures 2 and 3. As shown in Figure 2, the differential pressure Δ1 is measured by the supply-side pressure sensor S3 and the recovery-side pressure sensor S4 while the dialysate is flowing in the reverse direction, and then the differential pressure Δ2 is measured while the dialysate is flowing in the forward direction, as shown in Figure 3. After measuring the differential pressure Δ2, the control means 5 calculates the difference Δpost between the differential pressure Δ1 and the differential pressure Δ2, and compares this difference Δpost with a third threshold. If Δpost is lower than the third threshold, the control means 5 can determine that the fluid replacement passage 27A is connected in accordance with post-fluid replacement.

[0049] Conversely, the same determination can be made when the fluid supply passage 27A is connected to the pre-fluid supply connector C1, corresponding to the pre-fluid supply shown in Figures 4 and 5. As shown in Figure 4, the differential pressure Δ3 is measured by the supply-side pressure sensor S3 and the recovery-side pressure sensor S4 while the dialysate is flowing in the reverse direction, and further, as shown in Figure 5, the differential pressure Δ4 is ​​measured while the dialysate is flowing in the forward direction. After measuring the differential pressure Δ4, the control means 5 calculates the difference Δpre between the differential pressure Δ3 and the differential pressure Δ4, and compares this difference Δpre with a third threshold. If Δpre exceeds the third threshold, the control means 5 can determine that the fluid replacement passage 27A is connected in accordance with the pre-fluid replacement.

[0050] In the above embodiment, a so-called personal dialysis machine 1 was described in which dialysate is prepared by adding dialysate concentrate from a dialysate concentrate supply means to purified water supplied by a liquid supply means. However, a so-called console-type dialysis machine 1 may also be used, which supplies dialysate that has been prepared in advance by the liquid supply means. In the above embodiment, in order to determine the connection check of the fluid replacement passage 27A in parallel with the priming operation, it is necessary to perform the operations shown in Figures 2 and 3 (or Figures 4 and 5) to fill both the arterial passage 21 and the venous passage 22 with dialysate. However, if the above determination operation is performed after the priming operation is complete, the determination can be made using either the operation shown in Figure 2 or Figure 3 (or either Figure 4 or Figure 5). In other words, for example, in the state where the dialysate is flowed in the reverse direction as shown in Figure 2, the pressure difference Δ1 measured by the supply-side pressure sensor S3 and the recovery-side pressure sensor S4 can be determined by using a pre-set threshold value, and the operation shown in Figure 2 alone can be used to make a determination. [Explanation of symbols]

[0051] 1 Dialysis machine 2 Dialysis machine 3 Blood circuit 4 Dialysate circuit 21 Arterial passage 22 Venous passage 24A Piping for the first priming (connection passage) 24B Connection passage 25. Second priming piping (connection passage) 27A, B. Fluid replacement passage 54 Dialysis fluid supply passage 55 Dialysis fluid recovery passage 65 Dialysis fluid pump (fluid delivery means) C1 Pre-fluid replacement connector C2 Post-fluid replacement connector

Claims

1. The system comprises a dialyzer for hemodialysis, a dialyzer supply passage for supplying fresh dialyzer fluid to the dialyzer, a dialyzer recovery passage for collecting used dialyzer fluid that has passed through the dialyzer, a blood circuit consisting of an arterial passage for supplying blood to the dialyzer and a venous passage for draining blood from the dialyzer, a fluid replacement passage provided between the dialyzer supply passage and the blood circuit, and a fluid delivery means for delivering the dialyzer fluid from the dialyzer supply passage to the blood circuit via the fluid replacement passage. In a dialysis apparatus, the above-mentioned fluid replacement passage is provided so as to be selectively connectable to the arterial or venous passage of the blood circuit, The system comprises a supply-side pressure sensor for measuring the pressure of the liquid flowing through the dialysate supply passage, a recovery-side pressure sensor for measuring the pressure of the liquid flowing through the dialysate recovery passage, and a connecting passage having one end communicating with the arterial or venous passage of the blood circuit and the other end communicating with the dialysate recovery passage. Furthermore, the dialysis apparatus is characterized by having a determination means that determines whether the fluid supply means is connected to the arterial or venous passage based on the pressure difference between the pressure measured by the supply-side pressure sensor and the pressure measured by the recovery-side pressure sensor, while the fluid supply means causes the fluid to flow from the fluid supply passage into the blood circuit through the fluid supply passage, and the fluid has flowed from the arterial-side passage or the venous-side passage to the dialysate recovery passage via the connection passage.

2. The above determination means calculates the pressure difference between the pressure measured by the supply-side pressure sensor and the pressure measured by the recovery-side pressure sensor, while the fluid delivered by the fluid delivery means from the fluid replacement passage to the blood circuit is flowing out from the end of the arterial-side passage through the connecting passage to the dialysate recovery passage. The dialysis apparatus according to claim 1, characterized in that, if the above differential pressure is less than a first threshold, it is determined that the fluid replacement passage is connected to the arterial passage, and if the above differential pressure is greater than a first threshold, it is determined that the fluid replacement passage is connected to the venous passage.

3. The determination means calculates the pressure difference between the pressure measured by the supply-side pressure sensor and the pressure measured by the recovery-side pressure sensor while the fluid delivered by the fluid delivery means from the fluid replacement passage to the blood circuit is flowing out from the end of the venous-side passage through the connecting passage to the dialysate recovery passage. The dialysis apparatus according to claim 1, characterized in that if the above differential pressure is less than a second threshold, it is determined that the fluid replacement passage is connected to the venous passage, and if the above differential pressure is greater than a second threshold, it is determined that the fluid replacement passage is connected to the arterial passage.

4. A method for checking the connection of a fluid replacement passage, comprising: a dialyzer for performing hemodialysis; a dialyzer supply passage for supplying fresh dialyzer fluid to the dialyzer; a dialyzer recovery passage for recovering used dialyzer fluid that has passed through the dialyzer; a blood circuit consisting of an arterial passage for supplying blood to the dialyzer and a venous passage for draining blood from the dialyzer; a fluid replacement passage provided between the dialyzer supply passage and the blood circuit; a fluid delivery means for delivering dialyzer fluid from the dialyzer supply passage to the blood circuit via the fluid replacement passage; and a control means for controlling the operation of the fluid delivery means, wherein before performing dialysis treatment, the control means determines whether the fluid replacement passage is connected to the arterial passage or the venous passage in the blood circuit. A supply-side pressure sensor for measuring the pressure in the dialysate supply passage and a recovery-side pressure sensor for measuring the pressure in the dialysate recovery passage are provided. A method for checking the connection of a fluid replacement passage, characterized in that, with either the arterial or venous passage of the blood circuit connected to the dialysate recovery passage, the control means operates the fluid delivery means to cause fluid to flow from the fluid replacement passage into the blood circuit, and with the fluid flowing from the arterial or venous passage to the dialysate recovery passage, the control means determines whether the fluid replacement passage is connected to the arterial or venous passage based on the pressure difference between the pressure measured by the supply-side pressure sensor and the pressure measured by the recovery-side pressure sensor.

5. The method for checking the connection of a fluid infusion passage according to Claim 4, characterized in that, while the control means operates the fluid delivery means to deliver fluid from the fluid infusion passage to the blood circuit, and the fluid flows out from the end of the arterial passage through the connecting passage to the dialysate recovery passage, the control means calculates the differential pressure between the pressure measured by the supply-side pressure sensor and the pressure measured by the recovery-side pressure sensor, and the control means determines that the fluid infusion passage is connected to the arterial passage if the differential pressure is less than a first threshold, and determines that the fluid infusion passage is connected to the venous passage if the differential pressure is greater than a first threshold.

6. The method for checking the connection of a fluid infusion passage according to Claim 4, characterized in that, while the control means operates the fluid delivery means to deliver fluid from the fluid infusion passage to the blood circuit, and the fluid flows out from the end of the venous passage through the connecting passage to the dialysate recovery passage, the control means calculates the differential pressure between the pressure measured by the supply-side pressure sensor and the pressure measured by the recovery-side pressure sensor, and the control means determines that the fluid infusion passage is connected to the venous passage if the differential pressure is less than a second threshold, and determines that the fluid infusion passage is connected to the arterial passage if the differential pressure is greater than a second threshold.

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