Blood purification apparatus

Abstract

This blood purification apparatus comprises: a first electrode that is in contact with an arterial blood line connected to a blood purifier; a second electrode that is in contact with a venous blood line connected to the blood purifier; and a measurement unit that measures the impedance between the first electrode and the second electrode. At least one of the first electrode and the second electrode is provided with an electrode unit (60). The electrode unit (60) includes a reception part (62) in which a tube (58) provided in the arterial blood line or the venous blood line is disposed. The reception part (62) is provided with: a contact surface (64) that is in contact with the outer surface of the tube (58); and an electrode part (66) provided along the contact surface (64).

Description

Blood purification device

[0001] The present invention relates to a blood purification device.

[0002] In blood purification treatment, needles for blood withdrawal and blood return are punctured into the patient's blood vessels to connect the blood circuit. If the needle comes out during treatment, the treatment cannot be continued. Therefore, it is preferable to monitor whether the needle is properly punctured during treatment. For example, a technique is known in which the impedance between electrodes provided in the blood circuit is measured, and based on the measured impedance, it is determined whether the needle is properly punctured (see, for example, Patent Document 1).

[0003] Japanese Patent No. 7108615

[0004] The blood circuit is a consumable that is discarded after each treatment. From the perspective of reducing the treatment cost, the electrodes for impedance measurement are preferably detachable from the disposable blood circuit and can be reused. However, if the detachable electrodes are not properly in contact with the blood circuit, the measurement accuracy of the impedance may decrease, and there is a risk that it may not be possible to properly monitor whether the needle is properly punctured.

[0005] The present invention has been made in view of such problems, and one of its exemplary objects is to provide a technique for improving the accuracy of impedance measurement in a blood circuit.

[0006] A blood purification device according to an aspect of the present invention includes a first electrode that contacts a blood withdrawal side blood circuit connected to a blood purifier, a second electrode that contacts a blood return side blood circuit connected to the blood purifier, and a measurement unit that measures the impedance between the first electrode and the second electrode. At least one of the first electrode and the second electrode includes an electrode unit. The electrode unit includes a receiving portion in which a tube or a cuvette provided in the blood withdrawal side blood circuit or the blood return side blood circuit is disposed. The receiving portion includes a contact surface that contacts the outer surface of the tube or the cuvette, and an electrode portion provided along the contact surface.

[0007] Any combination of the above components, or components and expressions of the present invention that are mutually substituted between methods, devices, systems, etc. are also effective as aspects of the present invention.

[0008] According to the present invention, the accuracy of impedance measurement in blood circuits can be improved.

[0009] This is a perspective view showing the appearance of a blood purification device according to an embodiment. This is a diagram schematically showing the configuration of a blood purification system according to an embodiment. This is a side view schematically showing the configuration of the first electrode and the second electrode provided in the clamping part. This is a top view schematically showing the configuration of the first electrode and the second electrode provided in the clamping part. This is a cross-sectional view schematically showing the configuration of the electrode unit according to the first embodiment. This is a cross-sectional view schematically showing the tube that contacts the electrode unit according to the first embodiment. This is a cross-sectional view schematically showing the configuration of the electrode unit according to the second embodiment. This is a cross-sectional view schematically showing the configuration of the electrode unit according to the third embodiment. This is a cross-sectional view schematically showing the tube that contacts the electrode unit according to the third embodiment. This is a cross-sectional view schematically showing the configuration of the electrode unit according to the fourth embodiment. This is a cross-sectional view schematically showing the tube that contacts the electrode unit according to the fourth embodiment. This is a cross-sectional view schematically showing the configuration of the electrode unit according to the fifth embodiment. This is a cross-sectional view schematically showing the tube that contacts the electrode unit according to the fifth embodiment. This is a cross-sectional view schematically showing the configuration of the electrode unit according to the sixth embodiment. This is a cross-sectional view schematically showing the tube that contacts the electrode unit according to the sixth embodiment. This is a top view schematically showing the configuration of the electrode unit according to the seventh embodiment. This is a cross-sectional view schematically showing the configuration of the electrode unit according to the seventh embodiment. This is a schematic cross-sectional view showing a cuvette in contact with the electrode unit according to the seventh embodiment. This is a schematic cross-sectional view showing the configuration of the electrode unit according to the eighth embodiment. This is a schematic top view showing the configuration of the clamping portion according to another embodiment.

[0010] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description, the same elements will be denoted by the same reference numerals, and redundant explanations will be omitted as appropriate. To aid in understanding the description, the dimensional ratios of each component in each drawing do not necessarily correspond to the actual dimensional ratios.

[0011] Figure 1 is a schematic front view showing the configuration of a blood purification device 10 according to an embodiment. The blood purification device 10 is used for hemodialysis and is also called a dialysis machine or dialysis monitoring device. Figure 1 shows the device without consumables such as blood circuits and blood purifiers attached. The blood purification device 10 comprises a main body 12, a display unit 14, and an infusion pole 16.

[0012] The display unit 14 is located on the upper part of the main unit 12. The display unit 14 displays a screen showing the operating status of the blood purification device 10, etc. The display unit 14 is, for example, composed of a touch panel. The user can input user operations by touching the surface of the display unit 14.

[0013] The IV pole 16 is located on the side of the main body 12. The IV pole 16 is equipped with a blood purifier holder (not shown) for attaching a blood purifier, also known as a dialyzer. An infusion hook is provided at the top of the IV pole 16 for suspending an infusion bag, such as a saline solution bag.

[0014] A blood circuit is attached to the front surface 18 of the main body 12. A clamping part 20 and a blood pump 22 are provided on the front surface 18 of the main body 12. The clamping part 20 is configured to clamp and hold the blood circuit extending from the patient. The blood pump 22 houses the pump tube provided in the blood circuit. The blood pump 22 is a squeezing pump, and it generates a flow of blood or replacement fluid in the blood circuit by squeezing the housed pump tube.

[0015] Figure 2 is a schematic diagram showing the configuration of a blood purification system according to an embodiment. The blood purification system comprises a blood purification device 10, a blood purifier 24, and a blood circuit 26.

[0016] The blood purifier 24 has a blood inlet port 24a and a blood outlet port 24b connected to the blood circuit 26, and a dialysate inlet port 24c and a dialysate outlet port 24d connected to the dialysate supply unit 32. The blood purifier 24 has a hollow fiber housed inside. The inside of the hollow fiber is a blood flow path connecting the blood inlet port 24a and the blood outlet port 24b. The outside of the hollow fiber is a dialysate flow path connecting the dialysate inlet port 24c and the dialysate outlet port 24d. The hollow fiber has numerous tiny pores, and is configured to allow waste products and excess water in the blood to permeate into the dialysate through these numerous tiny pores.

[0017] The blood circuit 26 is composed of flexible tubes that serve as blood pathways. The material of the tubes constituting the blood circuit 26 is not particularly limited, but soft resin materials such as polyvinyl chloride (PVC) can be used. The outer diameter of the tubes constituting the blood circuit 26 is not particularly limited, but for example, it is about 5 mm to 7 mm. The blood circuit 26 comprises a blood withdrawal side blood circuit 28 and a blood return side blood circuit 30.

[0018] The blood withdrawal circuit 28 is a blood withdrawal tube that connects the blood vessel 92 of the patient 90 to the blood introduction port 24a of the blood purifier 24. The blood withdrawal circuit 28 includes a puncture needle 28a, a pump tube 28b, and an air trap chamber 28c. The puncture needle 28a is provided at the end of the blood withdrawal circuit 28 and is inserted into the blood vessel 92 of the patient 90. The pump tube 28b is the part that is attached to the blood pump 22 and has a larger diameter than the other parts. The outer diameter of the pump tube 28b is, for example, about 12 mm.

[0019] The blood return circuit 30 is a blood return tube that connects the patient's blood vessel 92 to the blood outlet port 24b of the blood purifier 24. The blood return circuit 30 includes a puncture needle 30a and an air trap chamber 30c. The puncture needle 30a is provided at the end of the blood return circuit 30 and is inserted into the patient's blood vessel 92.

[0020] The blood purification device 10 includes a dialysate supply unit 32. The dialysate supply unit 32 is configured to supply dialysate to the blood purifier 24 and to discharge dialysate from the blood purifier 24. The dialysate supply unit 32 includes a supply line L1, a discharge line L2, a dual pump 34, and a water removal pump 36.

[0021] The supply line L1 is the main pipe through which the dialysate supplied to the blood purifier 24 flows, and is connected to the dialysate inlet port 24c of the blood purifier 24. The discharge line L2 is the main pipe through which the dialysate discharged from the blood purifier 24 flows, and is connected to the dialysate outlet port 24d of the blood purifier 24. The dual pump 34 is installed in the middle of the supply line L1 and the discharge line L2 and controls the flow rate of the dialysate flowing through the supply line L1 and the discharge line L2. The water removal pump 36 is installed in the discharge line L2 in a bypass line L3 that bypasses the dual pump 34.

[0022] The blood purification device 10 comprises a first electrode 38, a second electrode 40, and a measuring unit 42. The first electrode 38 is detachably in contact with a tube constituting the blood withdrawal side blood circuit 28. The second electrode 40 is detachably in contact with a tube constituting the blood return side blood circuit 30. The measuring unit 42 is configured to measure the impedance between the first electrode 38 and the second electrode 40.

[0023] The measuring unit 42 may include, for example, an AC power supply, a voltmeter, and an ammeter. The AC power supply applies an AC voltage between the first electrode 38 and the second electrode 40. The AC power supply may be a variable frequency power supply that can change or sweep the frequency of the AC voltage. The voltmeter measures the voltage between the first electrode 38 and the second electrode 40. The ammeter measures the current flowing between the first electrode 38 and the second electrode 40. The measuring unit 42 calculates the impedance from the measured voltage and current values. The measuring unit 42 may also calculate the frequency characteristics of the impedance. The measuring unit 42 may also calculate the relationship between frequency and impedance, or the relationship between the resistance component and the capacitance component of the impedance.

[0024] The first electrode 38 and the second electrode 40 can be provided inside the clamping portion 20. In this case, by placing the blood withdrawal side blood circuit 28 and the blood return side blood circuit 30 in the clamping portion 20, the blood withdrawal side blood circuit 28 can be brought into contact with the first electrode 38, and the blood return side blood circuit 30 can be brought into contact with the second electrode 40. By removing the blood withdrawal side blood circuit 28 and the blood return side blood circuit 30 from the clamping portion 20, the blood withdrawal side blood circuit 28 can be removed from the first electrode 38, and the blood return side blood circuit 30 can be removed from the second electrode 40.

[0025] The first electrode 38 and the second electrode 40 are preferably in contact with the tube constituting the blood circuit 26 at a distance of 1.5 m or less from the puncture needle 28a or 30a. By keeping the distance within 1.5 m, it becomes possible to measure the impedance appropriately.

[0026] The blood purification device 10 further comprises a control unit 44. The control unit 44 comprises, for example, a processor such as a CPU (Central Processing Unit), memory such as RAM (Random Access Memory) or ROM (Read Only Memory), and storage device such as an HDD (Hard Disk Drive) or SSD (Solid State Drive). The control unit 44 controls the overall operation of the blood purification device 10 according to a program, for example, by having the processor execute a program stored in memory. The processor may execute a program stored in any storage device other than memory, or a program obtained from any recording medium by a reader, or a program obtained via a network. The memory in which the program is stored may be volatile memory such as DRAM (Dynamic Random Access Memory), or non-volatile memory such as EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory, magnetoresistive memory, resistive random-access memory, or ferroelectric memory. Magnetic recording media such as non-volatile memory, magnetic tapes, and magnetic disks, as well as optical recording media such as optical disks, are examples of non-transitory, tangible, and computer-readable storage media.

[0027] The control unit 44 includes a determination unit 46. The determination unit 46 determines, based on the impedance measured by the measurement unit 42, whether the puncture needle 28a of the blood withdrawal side blood circuit 28 or the puncture needle 30a of the blood return side blood circuit 30 has been successfully inserted into the blood vessel 92 of the patient 90. For example, the determination unit 46 stores the impedance measured when both the blood withdrawal side and the blood return side puncture needles 28a and 30a are successfully inserted, and determines whether it is normal or abnormal by comparing the stored impedance with the currently measured impedance. The determination unit 46 may also store the frequency characteristics of the impedance and determine whether it is normal or abnormal by comparing the frequency characteristics of the impedance. For example, the determination unit 46 determines that it is normal if the difference in impedance (or its frequency characteristics) is less than a predetermined threshold, and determines that it is abnormal if the difference is greater than or equal to a predetermined threshold. An example of a specific determination method by the determination unit 46 is described in the prior art (Japanese Patent No. 7108615) mentioned above, and its contents are incorporated into this document by reference.

[0028] The control unit 44 includes a notification unit 48. The notification unit 48 outputs an alert if the determination unit 46 determines that the puncture was not performed correctly, i.e., that there is an abnormality. The notification unit 48 may also notify by outputting a warning sound or by displaying a warning image on the display unit 14.

[0029] Figure 3 is a schematic side view showing the configuration of the first electrode 38 and the second electrode 40 provided on the clamping portion 20. The clamping portion 20 comprises a base portion 50 and a lid portion 52. The base portion 50 is the part fixed to the front surface 18 of the main body portion 12 of the blood purification device 10. The lid portion 52 is attached to the base portion 50 via a hinge 54. The lid portion 52 is configured to be openable and closable between a closed state that covers the upper surface 56 of the base portion 50 and an open state that separates from the upper surface 56 of the base portion 50. Figure 3 shows the lid portion 52 in the closed state. The first electrode 38 and the second electrode 40 are provided on the upper surface 56 of the base portion 50.

[0030] Figure 4 is a schematic top view showing the configuration of the first electrode 38 and the second electrode 40 provided on the clamping portion 20. In Figure 4, for the sake of simplicity, the lid portion 52 is omitted, and the upper surface 56 of the base portion 50 is shown exposed. It also shows the state in which the tubes 58 constituting the blood circuit 26 are placed on the clamping portion 20. The tubes 58 constituting the blood withdrawal side blood circuit 28 are placed on the first electrode 38. The tubes 58 constituting the blood return side blood circuit 30 are placed on the second electrode 40. The first electrode 38 and the second electrode 40 extend along the longitudinal direction of the tubes 58.

[0031] In Figures 3 and 4, the direction perpendicular to the upper surface 56 of the base 50 is defined as the z-direction, and the directions perpendicular to the z-direction are defined as the x-direction and the y-direction. The x-direction is the width direction of the tube 58, and the y-direction is the longitudinal direction of the tube 58. In this specification, the direction exiting the upper surface 56 of the base 50 may be referred to as the upward direction, and the direction entering the upper surface 56 of the base 50 may be referred to as the downward direction. These directions do not limit the orientation of the clamping portion 20, the first electrode 38, and the second electrode 40 when in use.

[0032] As shown in Figure 4, after the blood circuit 26 is placed on the upper surface 56 of the base 50, the lid 52 is closed, thereby sandwiching and fixing the tubes 58 constituting the blood circuit 26 between the base 50 and the lid 52. The lid 52 is maintained in a closed state relative to the base 50 by a locking mechanism (not shown) or the like. The lid 52 may also be biased toward the base 50 by a biasing means (not shown), such as a spring, to maintain the closed state of the lid 52. This maintains the state in which the tubes 58 constituting the blood withdrawal side blood circuit 28 are in contact with the first electrode 38, and the state in which the tubes 58 constituting the blood return side blood circuit 30 are in contact with the second electrode 40.

[0033] In the configuration shown in Figures 3 and 4, the first electrode 38 and the second electrode 40 are provided on a common clamping portion 20. In a modified example, the blood purification device 10 may include a first clamping portion on which the first electrode 38 is provided and a second clamping portion on which the second electrode 40 is provided. Each of the first and second clamping portions may include a base and a cover, similar to the clamping portion 20 described above, and the first electrode 38 or the second electrode 40 may be provided on the upper surface of the base.

[0034] In another modification, the clamping portion 20 may be provided away from the front surface 18 of the main body 12. The clamping portion 20 may be configured as a clip that can be locked onto the tube 58 of the blood circuit 26 and connected to the main body 12 via a cable. The clamping portion 20 may be provided at the end of a cable extending from the main body 12. The first electrode 38 or the second electrode 40 may be electrically connected to the measuring unit 42 via a cable.

[0035] The specific configurations of the first electrode 38 and the second electrode 40 will be described below. The first electrode 38 and the second electrode 40 can each have a similar configuration. Hereafter, the common configuration relating to the first electrode 38 and the second electrode 40 will be referred to as the "electrode unit". Therefore, the first electrode 38 or the second electrode 40 can be equipped with the electrode unit described later.

[0036] (First Embodiment) Figure 5 is a schematic cross-sectional view showing the configuration of an electrode unit 60 according to the first embodiment. The electrode unit 60 includes a receiving portion 62 in which a tube 58 is arranged. The receiving portion 62 comprises a contact surface 64, an electrode portion 66, and a deformation portion 68.

[0037] The contact surface 64 contacts the outer surface of the tube 58 that constitutes the blood circuit 26. The contact surface 64 has a concave curved shape corresponding to the outer surface of the tube 58. The contact surface 64 has a cylindrical curved shape corresponding to, for example, the outer surface of a straight tube 58. The contact surface 64 defines a recessed receiving portion 62 that is recessed relative to the upper surface 56 of the base 50. The width w of the entrance of the receiving portion 62 is about the same as the outer diameter of the tube 58. The width w of the entrance of the receiving portion 62 may be larger or smaller than the outer diameter of the tube 58. The depth d of the receiving portion 62 is, for example, 50% or more, 60% or more, or 70% or more of the outer diameter of the tube 58, and 90% or less, or 80% or less of the outer diameter of the tube 58. The depth d of the receiving portion 62 may be about half the outer diameter of the tube 58, or 40% or less, or 30% or less of the outer diameter of the tube 58.

[0038] The electrode portion 66 is made of metal, for example, copper, aluminum, or stainless steel. The electrode portion 66 is electrically connected to the measuring portion 42, and an AC voltage is applied to it by the measuring portion 42. The electrode portion 66 is provided along the contact surface 64. The electrode portion 66 is parallel to the contact surface 64 and has a concave curved surface that has the same shape as the contact surface 64. The electrode portion 66 has, for example, a certain thickness. The thickness of the electrode portion 66 is not particularly limited, but for example, it is 0.1 mm or more and 10 mm or less. The electrode portion 66 does not have contact with the contact surface 64 and is separated from the contact surface 64. The electrode portion 66 is covered by a deformation portion 68 so as not to be exposed to the outside.

[0039] The deformable portion 68 is provided between the contact surface 64 and the electrode portion 66. The deformable portion 68 has a contact surface 64 and is in direct contact with the outer surface of the tube 58. The deformable portion 68 is made of a flexible or soft material that can be deformed by contact with the tube 58. The deformable portion 68 makes the contact surface 64 deformable. The deformable portion 68 is made of, for example, rubber or elastomer. The deformable portion 68 may be made of soft polyvinyl chloride. The deformable portion 68 may be an insulator or a conductor. In the latter case, the deformable portion 68 is made of rubber or elastomer mixed with a conductive material. The deformable portion 68 may have a constant thickness, and the thickness from the contact surface 64 to the electrode portion 66 may be constant regardless of location. The thickness of the deformed portion 68 is preferably greater than the wall thickness of the tube 58 (for example, about 0.7 mm to 1 mm), for example, 2 mm or more, 3 mm or 5 mm or more, and 20 mm or less, 15 mm or less, or 10 mm or less.

[0040] Figure 6 is a schematic cross-sectional view showing a tube 58 that contacts the electrode unit 60 according to the first embodiment. When the tube 58 is placed on the receiving portion 62 and pushed into the back of the receiving portion 62, the deformable portion 68 is pressed by the tube 58 and the contact surface 64 is deformed. The tube 58 is pressed downward by, for example, the closed lid portion 52. The lid portion 52 functions as a pressing portion that presses the tube 58 against the contact surface 64. The deformable portion 68 deforms to a shape corresponding to the outer surface of the tube 58 as the tube 58 is pressed against it. As a result, the contact surface 64 can be in close contact with the outer surface of the tube 58.

[0041] According to this embodiment, by providing a deformed portion 68 having a contact surface 64, the electrode unit 60 can be brought into close contact with the outer surface of the tube 58. Furthermore, the concave curved shape of the contact surface 64 improves the adhesion between the electrode unit 60 and the tube 58. As a result, the contact resistance between the tube 58 and the contact surface 64 can be reduced, and the decrease in accuracy of impedance measurement caused by contact resistance can be suppressed.

[0042] According to this embodiment, since the electrode portion 66 is covered by the deformation portion 68, it is possible to suppress a decrease in measurement accuracy caused by disturbances such as static electricity. Further, since the electrode portion 66 is not exposed to the outside, it is possible to prevent deterioration such as rust of the electrode portion 66 due to the adhesion of the dialysate or the like to the electrode portion 66.

[0043] (Second Embodiment) FIG. 7 is a cross-sectional view schematically showing the configuration of the electrode unit 60A according to the second embodiment. In the second embodiment, the shapes of the electrode portion 66A and the deformation portion 68A are different from those of the above-described embodiment. Hereinafter, the second embodiment will be described focusing on the differences from the above-described embodiment, and the description of the common points will be omitted as appropriate.

[0044] The electrode unit 60A includes a receiving portion 62A. The receiving portion 62A includes a contact surface 64, an electrode portion 66A, and a deformation portion 68A. The shape of the contact surface 64 is the same as that of the first embodiment described above. The electrode portion 66A is provided along the contact surface 64 but has a shape different from that of the contact surface 64. The electrode portion 66A has a U shape instead of a concave curved surface shape. The electrode portion 66A has a bottom portion 70a extending in the width direction (x direction) and side portions 70b extending in the depth direction (z direction). The bottom portion 70a and the side portions 70b have a flat plate shape. The electrode portion 66A may have only the bottom portion 70a and not have the side portions 70b. The deformation portion 68A is provided between the contact surface 64 and the electrode portion 66A, but the thickness from the contact surface 64 to the electrode portion 66A varies depending on the location.

[0045] Also in this embodiment, the same effects as those of the above-described embodiment can be obtained. According to this embodiment, since the electrode portion 66A has a flat plate shape, it becomes easier to deform the contact surface 64 more freely. Thereby, the adhesion of the contact surface 64 to the outer surface of the tube 58 can be improved.

[0046] (Third Embodiment) FIG. 8 is a cross-sectional view schematically showing the configuration of the electrode unit 60B according to the third embodiment. In the third embodiment, it is different from the above-described embodiment in that the depth dB of the receiving portion 62B is small and the radius of curvature of the contact surface 64B is relatively large. Hereinafter, the third embodiment will be described focusing on the differences from the above-described embodiment, and the description of the common points will be omitted as appropriate.

[0047] The electrode unit 60B includes a receiving portion 62B. The receiving portion 62B includes a contact surface 64B, an electrode portion 66B, and a deformation portion 68B. The contact surface 64B has, for example, a concave curved surface shape corresponding to the outer surface of the tube 58 when the tube 58 is crushed in the vertical direction. The contact surface 64B may have, for example, an elliptical cylindrical concave curved surface shape instead of a cylindrical shape. The radius of curvature of the bottom of the contact surface 64B is larger than the radius of curvature of the outer surface of the tube 58. The depth dB of the receiving portion 62B is, for example, less than 50% of the outer diameter of the tube 58, 40% or less, or 30% or less. The width wB of the entrance of the receiving portion 62B is larger than the outer diameter of the tube 58, 1.1 times or more, 1.3 times or more, or 1.5 times or more the outer diameter of the tube 58, and 2 times or less, 1.8 times or less, or 1.6 times or less the outer diameter of the tube 58.

[0048] The electrode portion 66B is provided along the contact surface 64B. The electrode portion 66B has a U-shaped configuration. The electrode portion 66B has a bottom portion 70a extending in the width direction (x direction) and side portions 70b extending in the depth direction (z direction). The electrode portion 66B may have the same concave curved surface shape as the contact surface 64B or may have a flat plate shape. The electrode portion 66B may have only the bottom portion 70a and no side portions 70b. The deformation portion 68B is provided between the contact surface 64B and the electrode portion 66B. The deformation portion 68B has the concave curved surface-shaped contact surface 64B.

[0049] FIG. 9 is a cross-sectional view schematically showing the tube 58 in contact with the electrode unit 60B according to the third embodiment. In the third embodiment, the tube 58 is crushed in the vertical direction between the base portion 50 and the lid portion 52, and has an elliptical cross-sectional shape with a small height and a large width of the tube 58. The deformation portion 68B is deformed into a shape corresponding to the outer surface of the tube 58 when the tube 58 is pressed. Since the contact surface 64B before deformation has a shape close to the outer surface of the tube 58 after being crushed, it can follow the shape of the outer surface of the crushed tube 58 even with a small amount of deformation. As a result, the contact surface 64B can be in close contact with the outer surface of the tube 58.

[0050] In this embodiment as well, the same effects as in the above-described embodiment can be achieved.

[0051] (Fourth Embodiment) Figure 10 is a schematic cross-sectional view showing the configuration of the electrode unit 60C according to the fourth embodiment. The fourth embodiment differs from the above-described embodiment in that the contact surface 64C is a flat surface. The fourth embodiment will be described below, focusing on the differences from the above-described embodiment, and the common points will be omitted from the explanation as appropriate.

[0052] The electrode unit 60C includes a receiving portion 62C. The receiving portion 62C comprises a contact surface 64C, an electrode portion 66C, and a deformation portion 68C. The contact surface 64C is a flat surface. The contact surface 64C is located at a position lower than the upper surface 56. The contact surface 64C forms the bottom surface of the receiving portion 62C. The contact surface 64C may be located at the same height as the upper surface 56 and formed to be flush with the upper surface 56. The electrode portion 66C is provided along the contact surface 64C. The electrode portion 66C has a flat plate shape corresponding to the flat contact surface 64C. The deformation portion 68C is provided between the contact surface 64C and the electrode portion 66C.

[0053] Figure 11 is a schematic cross-sectional view showing a tube 58 that contacts the electrode unit 60C according to the fourth embodiment. In the fourth embodiment, similar to the third embodiment, the tube 58 is compressed vertically between the base 50 and the lid 52. The deformed portion 68C deforms to a shape corresponding to the outer surface of the tube 58 as the tube 58 is pressed against it. The contact surface 64C before deformation is a flat surface, but because the curvature deformation of the outer surface of the tube 58 after compression is large, it can follow the shape of the compressed outer surface of the tube 58 even with a small amount of deformation. As a result, the contact surface 64C can be in close contact with the outer surface of the tube 58.

[0054] Furthermore, if the electrode unit 60C according to the fourth embodiment is used repeatedly, even if the tube 58 is removed, the shape of the contact surface 64C may not return to a perfectly flat surface, and a concave curved shape may be maintained. In that case, the electrode unit 60C can be considered to have a concave curved shape at the contact surface 64C, similar to the third embodiment.

[0055] In this embodiment as well, the same effects as in the above-described embodiment can be achieved.

[0056] (Fifth Embodiment) Figure 12 is a schematic cross-sectional view showing the configuration of the electrode unit 60D according to the fifth embodiment. The fifth embodiment differs from the above-described embodiment in that a pressing portion 72D is provided at the entrance of the receiving portion 62D. The fifth embodiment will be described below, focusing on the differences from the above-described embodiment, and the common points will be omitted from the explanation as appropriate.

[0057] The electrode unit 60D includes a receiving portion 62D and a pressing portion 72D. The receiving portion 62D comprises a contact surface 64D, an electrode portion 66D, and a deformation portion 68D. The contact surface 64D has a concave curved shape corresponding to the outer surface of the tube 58 when the tube 58 is compressed in the left-right direction. The contact surface 64D may have an elliptical concave curved shape, rather than being cylindrical. The radius of curvature at the bottom of the contact surface 64D is smaller than the radius of curvature of the outer surface of the tube 58. The depth dD of the receiving portion 62D is, for example, about the same as the outer diameter of the tube 58 or larger than the outer diameter of the tube 58. The depth dD of the receiving portion 62D is 1 or more, 1.1 or more, or 1.2 or more than the outer diameter of the tube 58, and 1.5 or less, 1.4 or less, or 1.3 or less than the outer diameter of the tube 58.

[0058] The electrode portion 66D is provided along the contact surface 64D. The electrode portion 66D has, for example, a U-shape. The electrode portion 66D has a bottom portion 70a extending in the width direction (x direction) and a side portion 70b extending in the depth direction (z direction). The electrode portion 66D may have a concave curved surface shape similar to the contact surface 64D, or it may have a flat plate shape. The deformable portion 68D is provided between the contact surface 64D and the electrode portion 66D. The deformable portion 68D has a concave curved surface contact surface 64D.

[0059] The pressing portion 72D is provided on the upper surface 56 of the base portion 50. The pressing portion 72D protrudes in the width direction along the upper surface 56 of the base portion 50. The pressing portion 72D is formed integrally with the base portion 50, for example. The pressing portion 72D defines an opening width smaller than the entrance of the receiving portion 62D.

[0060] Figure 13 is a schematic cross-sectional view showing a tube 58 that contacts the electrode unit 60D according to the fifth embodiment. In the fifth embodiment, the tube 58 is compressed in the left-right direction in the receiving portion 62D, resulting in an elliptical cross-sectional shape with a large height and a small width. The deformable portion 68D deforms to a shape corresponding to the outer surface of the tube 58 when the tube 58 is pressed against it. The contact surface 64D before deformation has a shape close to the outer surface of the tube 58 after it has been compressed, so it can follow the shape of the compressed outer surface of the tube 58 even with a small amount of deformation. As a result, the contact surface 64D can be in close contact with the outer surface of the tube 58.

[0061] The tube 58 is inserted into the receiving portion 62D in a state where it is compressed laterally in order to pass inside the pressing portion 72D. After being inserted inside the receiving portion 62D, the tube 58 tries to expand laterally inside the receiving portion 62D and return to its original shape. At this time, the pressing portion 72D restricts the deformation of the tube 58 as it tries to return to its original shape and holds the tube 58 in place so that it does not come out of the receiving portion 62D. As a result, the tube 58 maintains a state of contact with the contact surface 64D inside the receiving portion 62D.

[0062] In this embodiment as well, the same effects as in the above-described embodiment can be achieved.

[0063] (Sixth Embodiment) Figure 14 is a schematic cross-sectional view showing the configuration of the electrode unit 60F according to the sixth embodiment. The sixth embodiment differs from the above-described embodiment in that the lid portion 52 is provided with an opposing electrode portion 76 and an opposing deformation portion 78. The sixth embodiment will be described below, focusing on the differences from the above-described embodiment, and the common points will be omitted from the explanation as appropriate.

[0064] The electrode unit 60E includes a receiving portion 62 and a pressing portion 72E. The receiving portion 62 comprises a contact surface 64, an electrode portion 66, and a deformation portion 68. The pressing portion 72E comprises an opposing surface 74, an opposing electrode portion 76, and an opposing deformation portion 78. The receiving portion 62 is provided on the upper surface 56 of the base portion 50 and can be configured in the same manner as in the embodiment described above.

[0065] The pressing portion 72E is provided on the lid portion 52. The opposing surface 74 functions to contact the tube 58 placed in the receiving portion 62 and press the tube 58 against the contact surface 64. The opposing surface 74 has, for example, a flat shape. The opposing surface 74 may have a concave curved shape, or a cylindrical curved shape corresponding to the outer surface of the tube 58.

[0066] The counter electrode portion 76 can be configured in the same way as the electrode portion 66. The counter electrode portion 76 is made of metal, for example, copper, aluminum, or stainless steel. The counter electrode portion 76 is electrically connected to the electrode portion 66. The counter electrode portion 76 is electrically connected to the measuring portion 42, and an AC voltage is applied by the measuring portion 42. The counter electrode portion 76 is parallel to the opposing surface 74. The counter electrode portion 76 is provided along the opposing surface 74. The counter electrode portion 76 may have the same shape as the opposing surface 74. The counter electrode portion 76 may have a flat plate shape, a concave curved surface shape, or a U-shape. The counter electrode portion 76 may have a certain thickness. The thickness of the counter electrode portion 76 is not particularly limited, but for example, it is 0.1 mm or more and 10 mm or less. The counter electrode portion 76 does not have an opposing surface 74 and is spaced apart from the opposing surface 74. The counter electrode portion 76 is covered by an opposing deformation portion 78 so as not to be exposed to the outside.

[0067] The opposing deformation portion 78 is provided between the opposing surface 74 and the opposing electrode portion 76. The opposing deformation portion 78 has an opposing surface 74 and is in direct contact with the outer surface of the tube 58. The opposing deformation portion 78 is made of a flexible or soft material that can be deformed by contact with the tube 58. The opposing deformation portion 78 makes the opposing surface 74 deformable. The opposing deformation portion 78 is made of, for example, rubber or elastomer. The opposing deformation portion 78 may be made of soft polyvinyl chloride. The opposing deformation portion 78 may be an insulator or a conductor. In the latter case, the opposing deformation portion 78 is made of rubber or elastomer mixed with a conductive material. The opposing deformation portion 78 may have a constant thickness, and the thickness from the opposing surface 74 to the opposing deformation portion 78 may be constant regardless of location. The thickness of the opposing deformation portion 78 is preferably greater than the wall thickness of the tube 58 (for example, about 0.7 mm to 1 mm), for example, 2 mm or more, 3 mm or 5 mm or more, and 20 mm or less, 15 mm or less, or 10 mm or less.

[0068] Figure 15 is a schematic cross-sectional view showing a tube 58 that contacts the electrode unit 60E according to the sixth embodiment. The tube 58 is positioned between the contact surface 64 and the opposing surface 74. The deformable portion 68 deforms to a shape corresponding to the outer surface of the tube 58 when the tube 58 is pressed against it. The opposing deformable portion 78 deforms to a shape corresponding to the outer surface of the tube 58 when the tube 58 is pressed against it. As a result, the tube 58 can be in close contact with both the contact surface 64 and the opposing surface 74.

[0069] In this embodiment as well, the same effects as in the above-described embodiment can be achieved. According to this embodiment, by sandwiching the tube 58 between the two electrode portions 66 and 76, the accuracy of impedance measurement can be further improved. In addition, the contact resistance between the tube 58 and the opposing surface 74 can be reduced, preventing a decrease in impedance measurement accuracy caused by contact resistance. Since the opposing electrode portion 76 is covered by the opposing deformation portion 78, a decrease in measurement accuracy caused by disturbances such as static electricity can be suppressed. Furthermore, since the opposing electrode portion 76 is not exposed to the outside, deterioration of the opposing electrode portion 76 due to the adhesion of dialysis fluid, etc. to the opposing electrode portion 76 can be prevented.

[0070] The sixth embodiment may be combined with the second, third, or fourth embodiment described above. That is, electrode portions 66A, 66B, and 66C may be used instead of electrode portion 66, and deformation portions 68A, 68B, and 68C may be used instead of deformation portion 68. In a modified example of the sixth embodiment, the electrode unit 60E may not include the opposing electrode portion 76. In a modified example of the sixth embodiment, the electrode unit 60E may not include the opposing deformation portion 78.

[0071] Figure 16 is a schematic top view showing the configuration of the electrode unit 60F according to the seventh embodiment. In the seventh embodiment, a cuvette 80 is provided in the blood circuit 26, and the electrode unit 60F is configured to be in contact with the cuvette 80. The cuvette 80 has, for example, a rectangular parallelepiped shape and a flat surface that contacts the electrode unit 60F. Tubes 58 are connected to both ends of the cuvette 80. The outer surface of the cuvette 80 has a larger surface area per unit length than the tubes 58. Therefore, by using the cuvette 80, the contact area with the electrode unit 60F can be increased, and the accuracy of impedance measurement can be improved.

[0072] Figure 17 is a schematic cross-sectional view showing the configuration of the electrode unit 60F according to the seventh embodiment. The electrode unit 60F includes a receiving portion 62F and a pressing portion 72F. The receiving portion 62F includes a contact surface 64F, an electrode portion 66F, and a deformation portion 68F. The pressing portion 72F includes an opposing surface 74F, an opposing electrode portion 76F, and an opposing deformation portion 78F. The electrode unit 60F can be configured in the same manner as the sixth embodiment described above, except that it is configured to receive the cuvette 80.

[0073] The receiving portion 62F is configured to receive the cuvette 80. The contact surface 64F has a shape corresponding to the outer surface of the cuvette 80. The contact surface 64F has a shape that allows it to contact, for example, the bottom surface and the side surface of the cuvette 80. The electrode portion 66F is provided along the contact surface 64F. The electrode portion 66F has a U-shape and has, for example, a bottom portion 70a parallel to the bottom surface of the cuvette 80 and a side portion 70b parallel to the side surface of the cuvette 80. The electrode portion 66F may have a flat plate shape, or it may only have a bottom portion 70a parallel to the bottom surface of the cuvette 80. The deformation portion 68F is provided between the contact surface 64F and the electrode portion 66F. The deformation portion 68F has the contact surface 64F.

[0074] The opposing surface 74F functions to contact the top surface of the cuvette 80, which is placed in the receiving portion 62F, and to press the cuvette 80 against the contact surface 64F. The opposing surface 74F has, for example, a flat shape. The opposing electrode portion 76F is parallel to the opposing surface 74F and has a flat plate shape. The opposing deformation portion 78F is provided between the opposing surface 74F and the opposing electrode portion 76F. The opposing deformation portion 78F has the opposing surface 74F.

[0075] Figure 18 is a schematic cross-sectional view showing a cuvette 80 in contact with an electrode unit 60F according to the seventh embodiment. The cuvette 80 has a bottom surface 80a, a top surface 80b, and a side surface 80c. The cuvette 80 can be made of a soft or hard resin material. The cuvette 80 may be made of a transparent material or an opaque material.

[0076] The cuvette 80 is positioned between the base 50 and the lid 52. The bottom surface 80a and side surface 80c of the cuvette 80 are in contact with the contact surface 64F. The top surface 80b of the cuvette 80 is in contact with the opposing surface 74F. The deformable portion 68F and the opposing deformable portion 78F deform to a shape corresponding to the outer surface of the cuvette 80 as the cuvette 80 is pressed against them. As a result, the contact surface 64F and the opposing surface 74F can be in close contact with the outer surface of the cuvette 80.

[0077] In this embodiment as well, the same effects as in the above-described embodiment can be achieved. According to this embodiment, by using the cuvette 80 to measure impedance, the contact area between the blood circuit and the electrode parts 66F and 76F can be increased, further improving the accuracy of impedance measurement. In addition, the contact resistance with the cuvette 80 at the contact surface 64F or the opposing surface 74 can be reduced, preventing a decrease in the accuracy of impedance measurement due to contact resistance.

[0078] In a modified example of the seventh embodiment, the pressing portion 72F may not include the opposing electrode portion 76F. In a modified example of the seventh embodiment, the pressing portion 72F may not include the opposing deformation portion 78F. In a modified example of the seventh embodiment, the electrode unit 60F may not include the pressing portion 72F.

[0079] (Eighth Embodiment) Figure 19 is a schematic cross-sectional view showing the configuration of the electrode unit 60G according to the eighth embodiment. The eighth embodiment differs from the above-described embodiment in that the electrode portion 66G has a contact surface 64G and does not have a deformable portion 68. It also differs from the above-described embodiment in that the opposing electrode portion 76G has an opposing surface 74G and does not have an opposing deformable portion 78. The eighth embodiment will be described below, focusing on the differences from the above-described embodiments, and the common points will be omitted as appropriate.

[0080] The electrode unit 60G includes a receiving portion 62G and a pressing portion 72G. The receiving portion 62G comprises a contact surface 64G and an electrode portion 66G. The pressing portion 72G comprises an opposing surface 74G and an opposing electrode portion 76G. The electrode portion 66G has a concave curved contact surface 64G corresponding to the outer surface shape of the tube 58. The contact surface 64G may have a radius of curvature corresponding to the outer diameter of the tube 58. The contact surface 64G may have a radius of curvature larger than the radius of curvature of the outer surface of the tube 58, and may have a concave curved shape corresponding to the outer surface shape of the tube 58 when it is compressed in the vertical direction as shown in Figure 5. The contact surface 64G may have a radius of curvature smaller than the radius of curvature of the outer surface of the tube 58, and may have a concave curved shape corresponding to the outer surface shape of the tube 58 when it is compressed in the horizontal direction as shown in Figure 13. The opposing electrode portion 76G has an opposing surface 74G that is either flat or concave.

[0081] According to this embodiment, since the electrode portion 66G has a concave curved contact surface 64G, the adhesion of the electrode portion 66G to the tube 58 can be improved. According to this embodiment, the accuracy of impedance measurement can be improved by sandwiching the tube 58 between the two electrode portions 66G and 76G.

[0082] In a modified version of the eighth embodiment, the electrode unit 60G may not include a counter electrode portion 76G. In a modified version of the eighth embodiment, the electrode unit 60G may further include a protective film covering at least one of the electrode portion 66G and the counter electrode portion 76G. The protective film can be made of, for example, a hard or soft resin material. The protective film can protect the electrode portion 66G or the counter electrode portion 76G from being exposed to the outside.

[0083] (Another Embodiment) Figure 20 is a schematic top view showing the configuration of the clamping portion 120 according to another embodiment. The clamping portion 120 includes a first electrode 38, a second electrode 40, a first clamp portion 102, a second clamp portion 104, a first tube detection portion 106, a second tube detection portion 108, a first blood detection portion 110, a second blood detection portion 112, a first bubble detection portion 114, and a second bubble detection portion 116. In Figure 20, the positions of the tubes 58 constituting the blood circuit 26 are indicated by dashed lines.

[0084] The first electrode 38, the first clamp portion 102, the first tube detection portion 106, the first blood detection portion 110, and the first bubble detection portion 114 are arranged in a line on the upper surface 56 of the clamp portion 120. The tube 58 constituting the blood withdrawal side blood circuit 28 is placed on the first electrode 38, the first clamp portion 102, the first tube detection portion 106, the first blood detection portion 110, and the first bubble detection portion 114. Note that the first electrode 38, the first clamp portion 102, the first tube detection portion 106, the first blood detection portion 110, and the first bubble detection portion 114 may be arranged in an order different from the order shown in the figure.

[0085] The second electrode 40, the second clamp portion 104, the second tube detection portion 108, the second blood detection portion 112, and the second bubble detection portion 116 are arranged in a line on the upper surface 56 of the clamping portion 120. The tube 58 constituting the blood return side blood circuit 30 is placed on top of the second electrode 40, the second clamp portion 104, the second tube detection portion 108, the second blood detection portion 112, and the second bubble detection portion 116. Note that the second electrode 40, the second clamp portion 104, the second tube detection portion 108, the second blood detection portion 112, and the second bubble detection portion 116 may be arranged in an order different from the order shown in the figure.

[0086] Each of the first clamp portion 102 and the second clamp portion 104 is configured to either close or open the flow path of the tube 58. Each of the first clamp portion 102 and the second clamp portion 104 includes a push rod 82 that is driven, for example, in the vertical direction. The push rod 82 closes the flow path of the tube 58 by pushing the tube 58, and opens the flow path of the tube 58 by moving the push rod away from the tube 58. The operation of the first clamp portion 102 and the second clamp portion 104 is controlled by the control unit 44.

[0087] The first tube detection unit 106 and the second tube detection unit 108 are each configured to detect whether or not the tube 58 is properly clamped. Each of the first tube detection unit 106 and the second tube detection unit 108 includes a switch 84 that detects, for example, vertical movement. If the tube 58 is clamped over the switch 84, the switch 84 is pressed down by the tube 58, and the clamping of the tube 58 is detected. If the tube 58 is not positioned over the switch 84, the switch 84 is not pressed down by the tube 58, and the clamping of the tube 58 is not detected. The detection results from the first tube detection unit 106 and the second tube detection unit 108 are sent to the control unit 44.

[0088] The first blood detection unit 110 and the second blood detection unit 112 are each configured to detect blood flowing through the tube 58. Each of the first blood detection unit 110 and the second blood detection unit 112 includes, for example, a light-emitting element 86a and a light-receiving element 86b. The light-emitting element 86a is, for example, an LED (Light Emitting Diode) and irradiates the tube 58 with light of a specific wavelength. The light-receiving element 86b is, for example, a photodiode and measures the intensity of the light transmitted through the tube 58. When blood flows through the tube 58, the transmittance is lower than when a clear liquid such as replacement fluid or dialysis fluid flows through it, so it is possible to detect whether or not blood is flowing based on the magnitude of the light intensity measured by the light-receiving element 86b. The detection results from the first blood detection unit 110 and the second blood detection unit 112 are sent to the control unit 44.

[0089] The first bubble detection unit 114 and the second bubble detection unit 116 are each configured to detect bubbles flowing through the tube 58. Each of the first bubble detection unit 114 and the second bubble detection unit 116 includes an ultrasonic transducer (not shown) and an ultrasonic sensor 88. The ultrasonic transducer is positioned above the tube 58 and is provided, for example, on the lid of the clamping portion 120. The ultrasonic sensor 88 is configured to measure the intensity of the ultrasonic waves generated by the ultrasonic transducer. When bubbles flow through the tube 58, the transmission rate of ultrasonic waves decreases compared to when there are no bubbles, so it is possible to detect whether or not bubbles are flowing based on the magnitude of the intensity measured by the ultrasonic sensor 88. The detection results from the first bubble detection unit 114 and the second bubble detection unit 116 are sent to the control unit 44.

[0090] According to the clamping portion 120 of this embodiment, impedance measurement, clamping, tube detection, blood detection, and air bubble detection of the blood circuit 26 can be achieved simply by placing the tubes 58 constituting the blood circuit 26 on the clamping portion 120, thereby improving user convenience.

[0091] The clamping portion 120 may comprise only a part of the configuration shown in Figure 20. The clamping portion 120 comprises a first electrode 38 and a second electrode 40, and may also comprise at least one of the following: a first clamp portion 102, a second clamp portion 104, a first tube detection portion 106, a second tube detection portion 108, a first blood detection portion 110, a second blood detection portion 112, a first bubble detection portion 114, and a second bubble detection portion 116.

[0092] In a modified example, instead of providing the clamping portion 120, a first clamping portion for clamping the blood withdrawal side blood circuit 28 and a second clamping portion for clamping the blood return side blood circuit 30 may be provided. The first clamping portion includes a first electrode 38 and may also include at least one of a first clamp portion 102, a first tube detection portion 106, a first blood detection portion 110, and a first bubble detection portion 114. The second clamping portion includes a second electrode 40 and may also include at least one of a second clamp portion 104, a second tube detection portion 108, a second blood detection portion 112, and a second bubble detection portion 116.

[0093] The present invention has been described above based on examples. Those skilled in the art will understand that the present invention is not limited to the above embodiments, that various design changes are possible, and that various modifications are possible, and that such modifications also fall within the scope of the present invention.

[0094] Several embodiments of the present invention will be described below.

[0095] A first aspect of the present invention is a blood purification device comprising: a first electrode that contacts a blood withdrawal side blood circuit connected to a blood purifier; a second electrode that contacts a blood return side blood circuit connected to the blood purifier; and a measuring unit for measuring the impedance between the first electrode and the second electrode, wherein at least one of the first electrode and the second electrode comprises an electrode unit, the electrode unit includes a receiving portion on which a tube provided in the blood withdrawal side blood circuit or the blood return side blood circuit is arranged, the receiving portion comprises a contact surface having a concave curved shape that contacts the outer surface of the tube, and an electrode portion provided along the contact surface. According to the first aspect, since the contact surface that contacts the outer surface of the tube constituting the blood circuit has a concave curved shape, the adhesion of the tube to the contact surface can be improved. This can improve the accuracy of impedance measurement.

[0096] A second aspect of the present invention is a blood purification device according to the first aspect, wherein the receiving portion further comprises a deformable portion provided between the contact surface and the electrode portion, and which makes the contact surface deformable. According to the second aspect, since the contact surface can be deformed to a shape corresponding to the outer surface of the tube, the adhesion of the tube to the contact surface can be improved.

[0097] A third aspect of the present invention is the blood purification device according to the second aspect, wherein the electrode portion has a concave curved surface shape. According to the third aspect, because the electrode portion has a concave curved surface shape corresponding to the contact surface, the electrode portion can be positioned closer to the tube. This improves the accuracy of impedance measurement.

[0098] A fourth aspect of the present invention is the blood purification device according to the second aspect, wherein the electrode portion has a flat plate shape. According to the fourth aspect, because the electrode portion has a flat plate shape, the deformable portion can be freely deformed to a shape corresponding to the outer surface of the tube. This improves the accuracy of impedance measurement.

[0099] A fifth aspect of the present invention is a blood purification device according to any one of the first to fourth claims, wherein the electrode unit further includes a pressing portion for pressing the tube against the contact surface. According to the fifth aspect, the adhesion of the tube to the contact surface can be improved by pressing the tube against the contact surface with the pressing portion.

[0100] A sixth aspect of the present invention is the blood purification device according to the fifth aspect, wherein the pressing portion comprises an opposing surface having a concave curved shape. According to the sixth aspect, by having an opposing surface having a concave curved shape corresponding to the outer surface of the tube, the adhesion of the tube to the contact surface can be improved while minimizing the crushing of the tube.

[0101] A seventh aspect of the present invention is the blood purification device according to the fifth aspect, wherein the pressing portion comprises opposing surfaces having a flat shape. According to the seventh aspect, the opposing surfaces having a flat shape allows the tube to be pressed so as to be crushed, thereby making the tube adhere closely to the contact surface.

[0102] An eighth aspect of the present invention is a blood purification device according to the fifth aspect, wherein the pressing portion comprises an opposing surface that contacts the tube and a counter electrode portion provided along the opposing surface. According to the eighth aspect, by further providing the counter electrode portion, the area of ​​the electrode positioned near the outer surface of the tube can be increased, thereby improving the accuracy of impedance measurement.

[0103] A ninth aspect of the present invention is a blood purification device comprising: a first electrode that contacts a blood withdrawal side blood circuit connected to a blood purifier; a second electrode that contacts a blood return side blood circuit connected to the blood purifier; and a measuring unit for measuring the impedance between the first electrode and the second electrode, wherein at least one of the first electrode and the second electrode comprises an electrode unit, the electrode unit includes a receiving portion on which a tube provided in the blood withdrawal side blood circuit or the blood return side blood circuit is arranged, the receiving portion comprises a contact surface that contacts the outer surface of the tube, a deformable portion that makes the contact surface deformable, and an electrode portion provided along the contact surface. According to the ninth aspect, since the contact surface can be deformed to a shape corresponding to the outer surface of the tube, the adhesion of the tube to the contact surface can be improved. This improves the accuracy of impedance measurement.

[0104] A tenth aspect of the present invention is the blood purification device according to the ninth aspect, wherein the deformable portion is made of a flexible material. According to the tenth aspect, by making the deformable portion of a flexible material, the contact surface can be freely deformed, and the adhesion of the tube to the contact surface can be improved.

[0105] An eleventh aspect of the present invention is a blood purification device according to the ninth or tenth aspect, wherein the electrode portion is covered by the deformation portion so as not to be exposed to the outside. According to the eleventh aspect, by covering the electrode portion, a decrease in measurement accuracy caused by disturbances such as static electricity can be suppressed. In addition, since the electrode portion is not exposed to the outside, deterioration of the electrode portion due to the adhesion of dialysis fluid, etc. to the electrode portion can be prevented.

[0106] A twelfth aspect of the present invention is a blood purification device according to any one of the ninth to eleventh aspects, wherein the electrode unit further includes a pressing portion for pressing the tube against the contact surface. According to the twelfth aspect, the adhesion of the tube to the contact surface can be improved by pressing the tube against the contact surface with the pressing portion.

[0107] A thirteenth aspect of the present invention is a blood purification device according to the twelfth aspect, wherein the pressing portion comprises an opposing surface that contacts the outer surface of the tube and an opposing deformation portion that makes the opposing surface deformable. According to the thirteenth aspect, by providing the opposing deformation portion, the adhesion of the tube to the contact surface can be improved while minimizing the crushing of the tube.

[0108] A fourteenth aspect of the present invention is the blood purification device described in the thirteenth aspect, wherein the opposing deformable portion is made of a flexible material. According to the fourteenth aspect, by making the opposing deformable portion out of a flexible material, the opposing surfaces can be freely deformed, and the adhesion of the tube to the contact surface can be improved while minimizing the crushing of the tube.

[0109] A fifteenth aspect of the present invention is a blood purification device according to the thirteenth or fourteenth aspect, wherein the pressing portion further comprises a counter electrode portion provided along the opposing surface. According to the fifteenth aspect, by further providing the counter electrode portion, the area of ​​the electrode positioned near the outer surface of the tube can be increased, thereby improving the accuracy of impedance measurement.

[0110] A sixteenth aspect of the present invention is a blood purification device according to the fifteenth aspect, wherein the counter electrode portion is covered by the counter deformation portion so as not to be exposed to the outside. According to the sixteenth aspect, by covering the counter electrode portion, a decrease in measurement accuracy caused by disturbances such as static electricity can be suppressed. In addition, since the counter electrode portion is not exposed to the outside, deterioration of the counter electrode portion due to the adhesion of dialysis fluid, etc. to the electrode portion can be prevented.

[0111] A seventeenth aspect of the present invention is a blood purification device according to any one of the first to sixteenth aspects, wherein the electrode unit is provided on a clamping portion that clamps the tube. According to the seventeenth aspect, by providing the electrode unit on the clamping portion, impedance measurement becomes possible simply by clamping the tube on the clamping portion. This improves user convenience.

[0112] An eighteenth aspect of the present invention is a blood purification device according to the seventeenth aspect, wherein the clamping portion comprises at least one of a bubble detection unit for detecting bubbles flowing through the tube, a blood detection unit for detecting blood flowing through the tube, a tube detection unit for detecting whether or not the tube is being clamped, and a clamping portion for closing or opening the flow path of the tube. According to the eighteenth aspect, by further providing at least one of the bubble detection unit, blood detection unit, tube detection unit, and clamping portion on the clamping portion, the installation work of the blood circuit can be simplified and user convenience can be improved.

[0113] A 19th aspect of the present invention is a blood purification device according to the 17th or 18th aspect, wherein the clamping portion is provided on the front surface of the blood purification device. According to the 19th aspect, by providing the clamping portion on the front surface of the device, the installation work of the blood circuit can be simplified, and user convenience can be improved.

[0114] A 20th aspect of the present invention is a blood purification device according to the 17th or 18th aspect, wherein the clamping portion is provided at the end of a cable extending from the blood purification device. According to the 20th aspect, the electrode unit can be attached to any location in the tube constituting the blood circuit, thereby improving user convenience.

[0115] A 21st aspect of the present invention is a blood purification device comprising: a first electrode that contacts a blood withdrawal side blood circuit connected to a blood purification device; a second electrode that contacts a blood return side blood circuit connected to the blood purification device; and a measuring unit for measuring the impedance between the first electrode and the second electrode, wherein at least one of the first electrode and the second electrode comprises an electrode unit, the electrode unit includes a receiving portion on which a cuvette provided in the blood withdrawal side blood circuit or the blood return side blood circuit is arranged, and the receiving portion comprises a contact surface that contacts the outer surface of the cuvette and an electrode portion provided along the contact surface. According to the 21st aspect, by providing a cuvette for impedance measurement in the blood circuit, the contact area between the blood circuit and the electrode portion can be increased, and the accuracy of impedance measurement can be improved.

[0116] A 22nd aspect of the present invention is a blood purification device according to the 21st aspect, wherein the electrode portion has a bottom portion provided along the bottom surface of the cuvette and a side portion provided along the side surface of the cuvette. According to the 22nd aspect, by having portions of the electrode portion along the bottom surface and side surface of the cuvette, the area of ​​the electrode portion close to the cuvette can be increased, and the accuracy of impedance measurement can be improved.

[0117] A 23rd aspect of the present invention is a blood purification device according to the 21st or 22nd aspect, wherein the receiving portion further comprises a deformable portion provided between the contact surface and the electrode portion, and which makes the contact surface deformable. According to the 23rd aspect, the contact surface can be deformed to a shape corresponding to the outer surface of the cuvette, thereby improving the adhesion of the cuvette to the contact surface. This improves the accuracy of impedance measurement.

[0118] A 24th aspect of the present invention is a blood purification device according to the 23rd aspect, wherein the deformed portion is in contact with the bottom and side surfaces of the cuvette. According to the 23rd aspect, the contact area between the cuvette and the contact surface can be increased, and the accuracy of impedance measurement can be improved.

[0119] A 25th aspect of the present invention is a blood purification device according to the 23rd or 24th aspect, wherein the electrode portion is covered by the deformation portion so as not to be exposed to the outside. According to the 25th aspect, by covering the electrode portion, a decrease in measurement accuracy caused by disturbances such as static electricity can be suppressed. In addition, since the electrode portion is not exposed to the outside, deterioration of the electrode portion due to the adhesion of dialysis fluid, etc. to the electrode portion can be prevented.

[0120] A 26th aspect of the present invention is a blood purification device according to any one of the 21st to 25th aspects, further comprising a pressing portion for pressing the cuvette against the contact surface. According to the 26th aspect, the adhesion of the cuvette to the contact surface can be improved by pressing the cuvette against the contact surface with the pressing portion.

[0121] A 27th aspect of the present invention is a blood purification device according to the 26th aspect, wherein the pressing portion comprises an opposing surface that contacts the cuvette and a counter electrode portion provided along the opposing surface. According to the 27th aspect, by further providing the counter electrode portion, the area of ​​the electrode positioned near the outer surface of the tube can be increased, thereby improving the accuracy of impedance measurement.

[0122] A 28th aspect of the present invention is a blood purification device according to the 27th aspect, wherein the pressing portion further comprises an opposing deformation portion provided between the opposing surface and the opposing electrode portion, which makes the opposing surface deformable. According to the 28th aspect, by providing the opposing deformation portion, the adhesion of the cuvette to the opposing surface can be improved, and the accuracy of impedance measurement can be improved.

[0123] A 29th aspect of the present invention is a blood purification device according to any one of the 21st to 28th aspects, wherein the electrode unit is provided in a clamping portion that holds the cuvette. By providing the electrode unit in the clamping portion, impedance measurement becomes possible simply by placing the cuvette in the clamping portion. This improves user convenience.

[0124] A 30th aspect of the present invention is a blood purification device according to the 29th aspect, wherein each of the blood withdrawal side blood circuit and the blood return side blood circuit is provided with a tube connected to the cuvette, and the clamping portion comprises at least one of a bubble detection unit for detecting bubbles flowing through the tube, a blood detection unit for detecting blood flowing through the tube, a tube detection unit for detecting whether or not the tube is being clamped, and a clamping portion for closing or opening the flow path of the tube. According to the 30th aspect, by further providing at least one of the bubble detection unit, blood detection unit, tube detection unit and clamping portion to the clamping portion, the installation work of the blood circuit can be simplified and user convenience can be improved.

[0125] A 31st aspect of the present invention is a blood purification device according to the 29th or 30th aspect, wherein the clamping portion is provided on the front surface of the blood purification device. According to the 28th aspect, by providing the clamping portion on the front surface of the device, the installation work of the blood circuit can be simplified, and user convenience can be improved.

[0126] A 32nd aspect of the present invention is a blood purification device according to the 29th or 30th aspect, wherein the clamping portion is provided at the end of a cable extending from the blood purification device. According to the 32nd aspect, the electrode unit can be attached to a cuvette provided at any location in the blood circuit, thereby improving user convenience.

[0127] According to the present invention, the accuracy of impedance measurement in blood circuits can be improved.

[0128] 10...Blood purification device, 12...Main body, 18...Front, 20...Clamping part, 24...Blood purifier, 26...Blood circuit, 28...Blood withdrawal side blood circuit, 28a...Puncture needle, 30...Blood return side blood circuit, 30a...Puncture needle, 38...First electrode, 40...Second electrode, 42...Measurement section, 58...Tube, 60...Electrode unit, 62...Receiving section, 64...Contact surface, 66...Electrode section, 68...Deformation section, 72...Pressing section, 74...Opposite surface, 76...Opposite electrode section, 78...Opposite deformation section, 80...Cuvette.

Claims

1. A blood purification device comprising: a first electrode that contacts a blood withdrawal side blood circuit connected to a blood purifier; a second electrode that contacts a blood return side blood circuit connected to the blood purifier; and a measuring unit for measuring the impedance between the first electrode and the second electrode, wherein at least one of the first electrode and the second electrode comprises an electrode unit, the electrode unit includes a receiving portion on which a tube or cuvette provided in the blood withdrawal side blood circuit or the blood return side blood circuit is disposed, and the receiving portion comprises: a contact surface that contacts the outer surface of the tube or cuvette; and an electrode portion provided along the contact surface.

2. The blood purification device according to claim 1, wherein the contact surface has a concave curved shape.

3. The blood purification apparatus according to claim 1 or 2, wherein the receiving portion further comprises a deformable portion that makes the contact surface deformable.

4. The blood purification device according to claim 3, wherein the deformed portion is provided between the contact surface and the electrode portion.

5. The blood purification device according to claim 3 or 4, wherein the deformable portion is made of a flexible material.

6. The electrode portion is covered by the deformed portion so as not to be exposed to the outside, according to any one of claims 3 to 5.

7. The blood purification apparatus according to any one of claims 3 to 6, wherein the deformed portion is in contact with the bottom surface and side surface of the cuvette.

8. The blood purification device according to any one of claims 1 to 7, wherein the electrode portion has a concave curved shape.

9. The blood purification apparatus according to any one of claims 1 to 7, wherein the electrode portion has a flat plate shape.

10. The blood purification apparatus according to any one of claims 1 to 9, wherein the electrode portion has a bottom portion provided along the bottom surface of the cuvette and a side portion provided along the side surface of the cuvette.

11. The blood purification apparatus according to any one of claims 1 to 10, wherein the electrode unit further includes a pressing portion for pressing the tube or cuvette against the contact surface.

12. The blood purification device according to claim 11, wherein the pressing portion comprises opposing surfaces having a concave curved shape.

13. The blood purification device according to claim 11, wherein the pressing portion comprises opposing surfaces having a flat shape.

14. The blood purification apparatus according to claim 11, wherein the pressing portion comprises an opposing surface that contacts the tube or the cuvette, and an opposing electrode portion provided along the opposing surface.

15. The blood purification device according to any one of claims 12 to 14, wherein the pressing portion further comprises an opposing deformation portion that makes the opposing surface deformable.

16. The blood purification apparatus according to claim 14, wherein the pressing portion further comprises an opposing deformation portion provided between the opposing surface and the opposing electrode portion, and which makes the opposing surface deformable.

17. The blood purification device according to claim 15 or 16, wherein the opposing deformable portion is made of a flexible material.

18. The blood purification device according to claim 16, wherein the opposing electrode portion is covered by the opposing deformation portion so as not to be exposed to the outside.

19. The blood purification apparatus according to any one of claims 1 to 18, wherein the electrode unit is provided in a clamping portion that clamps the tube or the cuvette.

20. The blood purification apparatus according to claim 19, wherein the clamping portion comprises at least one of a bubble detection unit for detecting bubbles flowing through the tube or a tube connected to the cuvette, a blood detection unit for detecting blood flowing through the tube, a tube detection unit for detecting whether or not the tube is being clamped, and a clamping portion for closing or opening the flow path of the tube.

21. The blood purification device according to claim 19 or 20, wherein the clamping portion is provided on the front surface of the blood purification device.

22. The blood purification device according to any one of claims 19 to 21, wherein the clamping portion is provided at the end of a cable extending from the blood purification device.

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