Blood purification device

Abstract

A blood purification device with improved safety is provided. [Solution] The blood purification device 1 comprises a blood circuit 2 for circulating the patient's blood extracorporeally, a blood purifier 3 provided in the blood circuit 2 and capable of purifying the blood, an impedance measuring unit 5 capable of measuring the frequency characteristics of the impedance of the liquid in the blood circuit 2, a normal frequency characteristic memory unit 83 that stores the frequency characteristics of the impedance under normal conditions according to the liquid flowing through the blood circuit 2, and a liquid determination unit 72 that compares the frequency characteristics of the impedance measured by the impedance measuring unit 5 with the frequency characteristics of the impedance under normal conditions stored in the normal frequency characteristic memory unit 83 to determine whether they match.

Description

[Technical Field]

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

[0002] In general, in blood purification treatments such as dialysis, a dialyzer is provided in a blood circuit that circulates a patient's blood extracorporeally, and a dialysate is introduced into or extracted from the dialyzer to perform blood purification. Blood purification treatment is carried out through various steps. Examples of steps in blood purification treatment include a priming step in which the blood circuit is filled with saline, a blood purification step in which blood is purified, a blood return step in which blood in the blood circuit is returned to the patient, and a drainage step in which the saline introduced into the blood circuit after blood return is drained.

[0003] Prior art document information related to the invention of this application includes Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2008 / 0195021 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional blood purification devices are prone to human error, such as proceeding to the next blood purification step before the filling of saline solution is complete during the priming step. To further enhance safety, a technology that can confirm whether the device is ready to start the next step is desired.

[0006] Therefore, an object of the present invention is to provide a blood purification device with improved safety. [Means for solving the problem]

[0007] A blood purification device according to one embodiment of the present invention comprises a blood circuit for extracorporeally circulating a patient's blood, a blood purifier provided in the blood circuit and capable of purifying the blood, an impedance measuring unit capable of measuring the frequency characteristics of the impedance of a liquid in the blood circuit, a normal frequency characteristic memory unit that stores the frequency characteristics of the impedance under normal conditions corresponding to the liquid flowing through the blood circuit, and a liquid determining unit that compares the frequency characteristics of the impedance measured by the impedance measuring unit with the frequency characteristics of the impedance under normal conditions stored in the normal frequency characteristic memory unit to determine whether they match.

[0008] In addition, a blood purification device according to one embodiment includes a blood circuit for extracorporeally circulating a patient's blood, a blood purifier provided in the blood circuit and capable of purifying the blood, an impedance measuring unit capable of measuring the impedance of a liquid in the blood circuit at a predetermined frequency, a normal frequency characteristic memory unit that stores the impedance at the predetermined frequency under normal conditions corresponding to the liquid flowing through the blood circuit, and a liquid determining unit that compares the impedance at the predetermined frequency measured by the impedance measuring unit with the impedance at the predetermined frequency under normal conditions stored in the normal frequency characteristic memory unit to determine whether they match. [Effects of the Invention]

[0009] According to the present invention, a blood purification device with improved safety can be provided. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating the configuration of a blood purification device according to one embodiment of the present invention. [Figure 2] 1(a) to 1(c) are diagrams showing examples of an arterial electrode and a venous electrode. [Figure 3] FIG. 10 is a diagram illustrating an example of frequency characteristics of impedance (impedance distribution). [Figure 4] 10(a) to 10(d) are explanatory diagrams showing specific examples of the liquid in the blood circuit during transition between processes and whether or not puncture has been performed. [Figure 5] 10(a) to 10(c) are explanatory diagrams showing specific examples of the liquid in the blood circuit during transition between steps and whether or not puncture has been performed. [Figure 6] This is the control flow when moving to the next process. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Embodiment Mode] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0012] (Overall configuration of blood purification device 1) Fig. 1 is a schematic diagram of a blood purification apparatus 1 according to this embodiment. As shown in Fig. 1, the blood purification apparatus 1 includes a blood circuit 2 for extracorporeally circulating a patient's blood, and a blood purifier 3 provided in the blood circuit 2 and capable of purifying the blood.

[0013] The blood circuit 2 is made of flexible tubing through which a liquid such as blood flows. The blood circuit 2 includes an arterial blood circuit 21 having an arterial puncture needle 211 attached to its tip, which can be inserted into a patient, and a venous blood circuit 22 having a venous puncture needle 221 attached to its tip, which can be inserted into a patient. The base ends of the arterial blood circuit 21 and the venous blood circuit 22 are each connected to the blood purifier 3. The arterial blood circuit 21 is provided with a blood pump 23, which is a peristaltic pump for pumping the liquid in the blood circuit 2. The venous blood circuit 22 is also provided with a gas-liquid separator 24 that separates air bubbles from the liquid flowing through the blood circuit 2.

[0014] The blood purifier 3, also referred to as a dialyzer, has a blood inlet port 3a, a blood outlet port 3b, a dialysate inlet port 3c, and a waste fluid outlet port 3d. The base end of the arterial blood circuit 21 is connected to the blood inlet port 3a, and the base end of the venous blood circuit 22 is connected to the blood outlet port 3b. A dialysate inlet line 41 extending from the device main body 4 is connected to the dialysate inlet port 3c, and a waste fluid outlet line 42 extending from the device main body 4 is connected to the waste fluid outlet port 3d. The blood purifier 3 contains multiple hollow fibers, with blood flowing through the hollow fibers and dialysate flowing outside the hollow fibers. The hollow fibers have numerous micropores, allowing impurities in the blood to permeate into the dialysate. By increasing the amount of waste fluid discharged compared to the amount of dialysate supplied, a process of removing water from the blood is performed. Although not shown, the blood circuit 2 may be provided with an air bubble detector, a pressure sensor, etc. as appropriate.

[0015] (Impedance measurement unit 5) The blood purification device 1 is equipped with an impedance measuring unit 5 capable of measuring the frequency characteristics of the impedance of the liquid in the blood circuit. The impedance measuring unit 5 has an arterial electrode 51 provided in the arterial blood circuit 21, a venous electrode 52 provided in the venous blood circuit 22, an oscillator 53 that applies an AC voltage between the arterial electrode 51 and the venous electrode 52 and can switch the frequency of the AC voltage, and an impedance measuring device 54 that measures the impedance for each frequency between the arterial electrode 51 and the venous electrode 52.

[0016] Here, the arterial electrode 51 is provided in the arterial blood circuit 21 between the blood pump 23 and the arterial puncture needle 211. The venous electrode 52 is provided in the venous blood circuit 22 between the gas-liquid separator 24 and the venous puncture needle 221. As shown in FIG. 2( a), the arterial electrode 51 and the venous electrode 52 are made of tubular conductors connected to flexible tubes that constitute the blood circuit 2. For example, the arterial electrode 51 and the venous electrode 52 are electrically connected to the oscillator 53 by attaching a clip of a clip-equipped electric wire extending from the oscillator 53 to the arterial electrode 51 or the venous electrode 52. The specific shapes of the arterial electrode 51 and the venous electrode 52 are not limited to those shown in the figure. They may have an electrode structure that does not directly contact the liquid as long as they can apply a voltage to the liquid flowing through the blood circuit 2. More specifically, the arterial electrode 51 and the venous electrode 52 may have a cylindrical electrode structure surrounding the flexible tube constituting the blood circuit 2, as shown in FIG. 2(b), or may have an electrode structure in which two metal plates sandwich the flexible tube constituting the blood circuit 2, as shown in FIG. 2(c). By configuring the arterial electrode 51 and the venous electrode 52 so that they do not come into direct contact with the liquid, it is possible to prevent the flow of liquid in the blood circuit 2 from being obstructed and also to use metals with low biocompatibility as electrodes. Note that the electrode structure shown in the figure is merely an example, and the electrode structures of the arterial electrode 51 and the venous electrode 52 can be modified as appropriate.

[0017] Oscillator 53 applies an AC voltage between arterial electrode 51 and venous electrode 52. Oscillator 53 is configured to be able to change the frequency of the applied AC voltage appropriately from low frequencies (e.g., several tens of Hz) to high frequencies (e.g., several MHz).

[0018] The impedance measuring instrument 54 measures the impedance between the arterial electrode 51 and the venous electrode 52 when an AC voltage is applied by the oscillator 53. By measuring the impedance with the impedance measuring instrument 54 while changing the frequency of the AC voltage applied by the oscillator 53, it is possible to measure the impedance for each frequency. The impedance between the arterial electrode 51 and the venous electrode 52 measured by the impedance measuring instrument 54 varies depending on the type of fluid in the blood circuit 2 and whether or not the patient has been punctured.

[0019] (Control device 6) The blood purification device 1 is equipped with a control device 6 that controls blood purification treatment, etc. The control device 6 has a control unit 7 and a storage unit 8. The control unit 7 is realized by appropriately combining a processing element, memory, storage device, software, interface, etc. The storage unit 8 is realized by a memory or storage device. The control unit 7 has a frequency characteristic acquisition unit 71, a liquid determination unit 72, a process transition restriction unit 73, and an abnormality notification unit 74.

[0020] (Frequency characteristic acquisition unit 71) The frequency characteristic acquisition unit 71 performs a frequency characteristic acquisition process to acquire the frequency characteristic of the impedance based on the impedance for each frequency measured by the impedance measuring instrument 54. The frequency characteristic acquisition unit 71 acquires the impedance measurement results from the impedance measuring instrument 54 while controlling the frequency of the oscillator 53, and stores the results in the measurement result storage unit 81. The frequency characteristic acquisition unit 71 then acquires the frequency characteristic of the impedance based on the impedance measurement results for each frequency stored in the measurement result storage unit 81. The acquired frequency characteristic of the impedance is stored in the measured frequency characteristic storage unit 82.

[0021] In this embodiment, the impedance distribution, which indicates the relationship between the resistance component and the capacitance component of the impedance, is used as the frequency characteristic of the impedance. More specifically, as shown in FIG. 3, the impedance distribution is a plot of the resistance component and capacitance component of the impedance for each measured frequency, with the value of the resistance component on the horizontal axis and the value of the capacitance component on the vertical axis. This impedance distribution (i.e., the frequency characteristic of the impedance) varies depending on the type of fluid in the blood circuit 2 and the state of puncturing the patient. Therefore, by comparing the impedance distribution under normal conditions in any process with the measured impedance distribution, it is possible to determine whether the process is in a normal state. Note that the vertical and horizontal axes of the impedance distribution may be reversed, and the resistance component of the impedance may be the vertical axis and the capacitance component may be the horizontal axis.

[0022] (Liquid determination unit 72, normal frequency characteristic storage unit 83) The normal state frequency characteristic storage unit 83 stores the frequency characteristics of the impedance (impedance distribution) under normal conditions according to the liquid flowing through the blood circuit 2. In this embodiment, the normal state frequency characteristic storage unit 83 stores, for each step of blood purification treatment, the frequency characteristics of the impedance (impedance distribution) under normal conditions according to the liquid flowing through the blood circuit in that step and the state of puncturing (a state in which the patient is not punctured, and a state in which the patient is punctured normally).

[0023] The liquid determination unit 72 compares the frequency characteristics of the impedance measured by the impedance measurement unit 5 (i.e., the frequency characteristics of the impedance stored in the measured frequency characteristics memory unit 82 by the frequency characteristics acquisition unit 71) with the frequency characteristics of the impedance under normal conditions stored in the normal frequency characteristics memory unit 83, and determines whether they match.

[0024] In this embodiment, when transitioning from any step to the next step of blood purification treatment, the liquid determination unit 72 is configured to compare the frequency characteristics of the impedance measured by the impedance measurement unit 5 with the frequency characteristics of the impedance in normal conditions for the next step stored in the normal frequency characteristic storage unit 83, and determine whether they match. This configuration makes it possible to confirm whether the next step is in a normal state at the start of the next step, and to restrict the start of the next step if the next step is not in a normal state (see the step transition restriction unit 73 described below), thereby improving safety.

[0025] 4(a), when transitioning from the priming step in which saline is filled into the blood circuit 2 before the start of blood purification treatment to the puncturing step in which the arterial puncture needle 211 and the venous puncture needle 221 are inserted into the patient, it is necessary that the blood circuit 2 has been completely filled with saline and that the patient has not been punctured. Therefore, the frequency characteristics of the impedance measured at the time of transition (measured frequency characteristics) are compared with the frequency characteristics of the impedance under normal conditions when the liquid in the blood circuit 2 is saline and no puncturing has been performed (normal frequency characteristics) to confirm whether they match.

[0026] 4(b), when transitioning from the puncturing process to the blood purification process, i.e., at the start of blood purification treatment, the blood circuit 2 must be filled with saline, contain some blood, and be in a state where the patient has been punctured. Therefore, the frequency characteristics of the impedance measured at the transition between processes (measured frequency characteristics) are compared with the frequency characteristics of the impedance under normal conditions when the liquid in the blood circuit 2 is saline and blood and puncturing has occurred (normal frequency characteristics) to confirm whether they match.

[0027] 4(c), when the process shifts from the blood return process, in which the blood in the blood circuit 2 is returned to the patient and filled with saline at the end of blood purification treatment, to the blood circuit AV connection process, in which the arterial puncture needle 211 and the venous puncture needle 221 are connected, the blood circuit 2 must be filled with saline, contain some blood, and be in a state where it has been punctured into the patient. Therefore, the frequency characteristics of the impedance measured at the time of the process shift (measured frequency characteristics) are compared with the frequency characteristics of the impedance under normal conditions when the liquid in the blood circuit 2 is saline and the needle has been punctured (normal frequency characteristics) to confirm whether they match.

[0028] 4(d), when transitioning from the blood circuit AV connection step to the blood circuit drainage step of draining the liquid in the blood circuit 2, the blood circuit 2 must be filled with saline and the patient must not be punctured. Therefore, the frequency characteristics of the impedance measured at the time of transition (measured frequency characteristics) are compared with the frequency characteristics of the impedance under normal conditions when the liquid in the blood circuit 2 is saline and no puncture is performed (normal frequency characteristics) to confirm whether they match.

[0029] Furthermore, as shown in Figure 5(a), when transitioning from the blood circuit drainage process to the cleaning and disinfection process, the liquid in the blood circuit 2 must be drained and the patient must not be punctured. Therefore, the frequency characteristics of the impedance measured at the time of transition (measured frequency characteristics) are compared with the frequency characteristics of the impedance under normal conditions when there is no liquid (air) in the blood circuit 2 and no puncture is performed (normal frequency characteristics) to confirm whether they match.

[0030] 5(b), when transitioning from the blood purification step to the mid-removal circulation step in which, when the patient leaves mid-removal, the arterial puncture needle 211 and the venous puncture needle 221 are connected to circulate blood within the blood circuit 2, the liquid within the blood circuit 2 must be blood and the patient must not have been punctured. Therefore, the frequency characteristics of the impedance measured at the time of the step transition (measured frequency characteristics) are compared with the frequency characteristics of the impedance under normal conditions when the liquid within the blood circuit 2 is blood and no puncture has been performed (normal frequency characteristics) to confirm whether they match.

[0031] 5(c), when transitioning from the post-intermediate withdrawal puncturing process in which the patient is punctured after midway withdrawal to the blood purification process, the liquid in the blood circuit 2 must be blood and the patient must be punctured. Therefore, the frequency characteristics of the impedance measured at the time of transition (measured frequency characteristics) are compared with the frequency characteristics of the impedance under normal conditions when the liquid in the blood circuit 2 is blood and puncturing has occurred (normal frequency characteristics) to confirm whether they match.

[0032] The liquid determination unit 72 determines whether the frequency characteristics of the measured impedance match the frequency characteristics of the impedance in a normal state by comparing the impedance distributions shown in Fig. 3. More specifically, the liquid determination unit 72 determines that the two do not match when the change in the frequency characteristics of the measured impedance from the frequency characteristics of the impedance in a normal state (the difference between the two) exceeds a certain level.

[0033] Furthermore, the liquid determination unit 72 may make a determination using the mutual correlation between the resistance component and capacitance component that make up the frequency characteristics of the impedance. For example, if the resistance component is R, the capacitance component is C, and the frequency during measurement is x, and the resistance component in the normal frequency characteristics is Rref(x), the capacitance component is Cref(x), and the resistance component in the measured frequency characteristics is Rcur(x), and the capacitance component is Ccur(x), the relationship shown in the following equations (1) and (2) can be obtained. Note that a and b in the following equations (1) and (2) are the lowest and highest frequencies output by the oscillator 53.

[0034]

number

[0035]

number

[0036] The closer the values ​​of R and C obtained by the above formulas (1) and (2) are to 0, the more similar the frequency characteristics of the measured impedance are to the frequency characteristics of the impedance under normal conditions. Therefore, when either or both of R and C obtained by the above formulas (1) and (2) exceed a preset threshold, it can be determined that the frequency characteristics of the measured impedance do not match the frequency characteristics of the impedance under normal conditions. Note that the determination method used by the liquid determination unit 72 is not limited to the above, and other pattern matching methods, etc., may also be used.

[0037] In this embodiment, the measurement of the impedance frequency characteristics and the determination by the liquid determination unit 72 are performed when transitioning from the current process to the next process (immediately before transitioning to the next process), but this is not limiting, and the measurement of the impedance frequency characteristics and the determination by the liquid determination unit 72 may be performed not only when transitioning to the next process but also while any process is being executed. In this case, the liquid determination unit 72 determines whether the measured impedance frequency characteristics match the impedance frequency characteristics under normal conditions in the current process.

[0038] (Process transition restriction unit 73) The process transition restriction unit 73 restricts the start of the next process when the liquid determination unit 72 determines that there is no match, and lifts the restriction on the start of the next process when the liquid determination unit 72 determines that there is match. As a result, if the state of the liquid in the blood circuit 2 or the puncture is not normal for the next process (i.e., if preparation for the next process is not complete), the next process will not be started, making it possible to improve safety.

[0039] (Abnormality notification unit 74) When the liquid determination unit 72 determines that the liquids do not match, the abnormality notification unit 74 notifies the user or administrator of the abnormality. The abnormality notification unit 74 may, for example, notify the user of the abnormality by sound or light using a buzzer or a warning light, or may display a message notifying the abnormality on a display or the like provided in the blood purification apparatus 1, or may notify the administrator of the abnormality by sending an email or the like.

[0040] (Control flow when moving to the next process) Figure 6 shows the control flow when moving to the next process. The control flow in Figure 6 is executed immediately before moving from any process to the next process.

[0041] First, in step S1, the frequency characteristic acquisition unit 71 uses the impedance measurement unit 5 to measure the impedance while changing the frequency of the voltage applied by the oscillator 53. The measured impedance for each frequency is stored in the measurement result storage unit 81. Then, in step S2, the frequency characteristic acquisition unit 71 obtains the frequency characteristic of the impedance (the impedance distribution in FIG. 3 ) based on the measurement results of the impedance for each frequency stored in the measurement result storage unit 81. The obtained frequency characteristic of the impedance is stored in the measurement frequency characteristic storage unit 82.

[0042] Thereafter, in step S3, the liquid determination unit 72 compares the frequency characteristics of the impedance obtained in step S2 with the frequency characteristics of the impedance under normal conditions in the next process stored in the normal-state frequency characteristic storage unit 83, and determines whether they match. If the determination in step S3 is No (N), in step S4 the process transition restriction unit 73 restricts the start of the next process. Then, in step S5, the abnormality notification unit 74 notifies of an abnormality. Thereafter, the process returns to step S1.

[0043] If the determination in step S3 is Yes (Y), in step S6, the process transition restriction unit 73 removes the restriction on the start of the next process, and the next process is started. After that, the process ends.

[0044] (Actions and Effects of the Embodiments) As described above, the blood purification device 1 according to this embodiment includes the impedance measuring unit 5 capable of measuring the frequency characteristics of the impedance of the liquid in the blood circuit 2, the normal-state frequency characteristic memory unit 83 that stores the frequency characteristics of the impedance under normal conditions corresponding to the liquid flowing through the blood circuit 2, and the liquid determining unit 72 that compares the frequency characteristics of the impedance measured by the impedance measuring unit 5 with the frequency characteristics of the impedance under normal conditions stored in the normal-state frequency characteristic memory unit 83 to determine whether they match.

[0045] This makes it possible to check whether preparation for the next step is complete, and if preparation is not complete, it becomes possible to take measures such as restricting the start of the next step, thereby further improving the safety of blood purification treatment.

[0046] Furthermore, in the blood purification device 1, the normal frequency characteristic storage unit 83 stores, for each step of blood purification treatment, the frequency characteristics of the impedance under normal conditions depending on the liquid flowing through the blood circuit 2 during that step and whether or not the patient has been punctured, and when transitioning from any step of blood purification treatment to the next step, the fluid determination unit 72 compares the frequency characteristics of the impedance measured by the impedance measurement unit 5 with the frequency characteristics of the impedance under normal conditions for the next step stored in the normal frequency characteristic storage unit 83 to determine whether they match. This makes it possible to determine whether preparation for the next step is complete, taking into account whether or not puncture has been performed, further improving safety.

[0047] Furthermore, the blood purification apparatus 1 is equipped with a process transition restriction unit 73 that restricts the start of the next process when the liquid determining unit 72 determines that the liquids do not match, and lifts the restriction on the start of the next process when the liquid determining unit 72 determines that the liquids match. This makes it possible to start the next process only when preparation for the next process is complete, further improving safety.

[0048] Furthermore, in the blood purification apparatus 1, the liquid determination unit 72 makes its determination by utilizing the mutual correlation between the resistance component and the capacitance component that make up the frequency characteristics of the impedance, thereby making it possible to accurately determine whether the frequency characteristics of the measured impedance match the frequency characteristics of the impedance in a normal state.

[0049] In the blood purification device 1, the impedance measuring unit 5 includes an arterial electrode 51 provided in the arterial blood circuit 21, a venous electrode 52 provided in the venous blood circuit 22, an oscillator 53 that applies an AC voltage between the arterial electrode 51 and the venous electrode 52 and can switch the frequency of the AC voltage, and an impedance measuring device 54 that measures the impedance for each frequency between the arterial electrode 51 and the venous electrode 52. This makes it possible to easily measure the frequency characteristics of the impedance.

[0050] (Variation) In the above embodiment, the frequency characteristics of the measured impedance are compared with the frequency characteristics of the normal impedance to determine whether the next step is ready. However, this is not limiting, and the determination can also be made using the impedance of a single preset frequency. In this case, the impedance measurement unit 5 only needs to be able to measure the impedance of the liquid in the blood circuit 2 at a predetermined frequency. Furthermore, the normal frequency characteristics storage unit 83 may store the impedance at a predetermined frequency in the normal state corresponding to the liquid flowing through the blood circuit 2. The liquid determination unit 72 may then compare the impedance at the predetermined frequency measured by the impedance measurement unit 5 with the impedance at the predetermined frequency in the normal state stored in the normal frequency characteristics storage unit 83 to determine whether they match. It is of course possible to make the determination using impedances at multiple frequencies, not just one frequency.

[0051] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiments will be described by using the reference numerals and the like in the embodiments. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiments.

[0052] [1] A blood purification device (1) comprising: a blood circuit (2) for circulating a patient's blood extracorporeally; a blood purifier (3) provided in the blood circuit (2) and capable of purifying the blood; an impedance measuring unit (5) capable of measuring the frequency characteristics of the impedance of a liquid in the blood circuit (2); a normal-state frequency characteristic memory unit (83) for storing the frequency characteristics of the impedance under normal conditions corresponding to the liquid flowing through the blood circuit (2); and a liquid determining unit (72) for comparing the frequency characteristics of the impedance measured by the impedance measuring unit (5) with the frequency characteristics of the impedance under normal conditions stored in the normal-state frequency characteristic memory unit (83) to determine whether they match.

[0053] [2] The blood purification device (1) described in [1], wherein the normal frequency characteristic storage unit (83) stores, for each step of blood purification treatment, the frequency characteristics of the impedance under normal conditions depending on the liquid flowing through the blood circuit (2) during that step and whether or not the patient has been punctured, and the liquid determination unit (72), when transitioning from any step of blood purification treatment to the next step, compares the frequency characteristics of the impedance measured by the impedance measurement unit (5) with the frequency characteristics of the impedance under normal conditions for the next step stored in the normal frequency characteristic storage unit (83) to determine whether they match.

[0054] [3] The blood purification device (1) described in [2], further comprising a process transition restriction unit (73) that restricts the start of the next process when the liquid determination unit (72) determines that there is no match, and that lifts the restriction on the start of the next process when the liquid determination unit (72) determines that there is match.

[0055] [4] The blood purification device (1) according to [1], wherein the liquid determination unit (72) makes the determination by utilizing the mutual correlation between the resistance component and the capacitance component that constitute the frequency characteristics of the impedance.

[0056] [5] The blood purification device (1) according to [1], wherein the blood circuit (2) comprises an arterial blood circuit (21) having an arterial puncture needle (211) attached to its tip that can be inserted into a patient, and a venous blood circuit (22) having a venous puncture needle (221) attached to its tip that can be inserted into a patient, and the impedance measurement unit (5) comprises an arterial electrode (51) provided in the arterial blood circuit (21), a venous electrode (52) provided in the venous blood circuit (22), an oscillator (53) that applies an AC voltage between the arterial electrode (51) and the venous electrode (52) and is capable of switching the frequency of the AC voltage, and an impedance measurement device (54) that measures the impedance for each frequency between the arterial electrode (51) and the venous electrode (52).

[0057] [6] A blood purification device (1) comprising: a blood circuit (2) for circulating a patient's blood extracorporeally; a blood purifier (3) provided in the blood circuit (2) and capable of purifying the blood; an impedance measuring unit (5) capable of measuring the impedance at a predetermined frequency of a liquid in the blood circuit (2); a normal frequency characteristic storage unit (83) for storing the impedance at the predetermined frequency under normal conditions corresponding to the liquid flowing through the blood circuit (2); and a liquid determination unit (72) for comparing the impedance at the predetermined frequency measured by the impedance measuring unit (5) with the impedance at the predetermined frequency under normal conditions stored in the normal frequency characteristic storage unit (83) to determine whether they match.

[0058] Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the above-described embodiments. It should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. Furthermore, the present invention can be appropriately modified and implemented within the scope of its spirit. [Explanation of symbols]

[0059] 1. Blood purification device 2…Blood circuit 21…Arterial blood circuit 211…Arterial side puncture needle 22...Venous blood circuit 221...Venous puncture needle 3...Blood purifier 5...Impedance measurement section 51...Arterial side electrode 52...Venous electrode 53...Oscillator 54...Impedance measuring instrument 6...Control device 7...Control unit 71...Frequency characteristic acquisition unit 72...Liquid determination section 73...Process transition restriction section 74...Abnormality alarm section 8…Storage section 81…Measurement result storage unit 82…Measurement frequency characteristic storage section 83...Normal frequency characteristic memory section

Claims

1. a blood circuit for extracorporeally circulating the patient's blood; a blood purifier that is provided in the blood circuit and is capable of purifying blood; an impedance measuring unit capable of measuring the frequency characteristics of the impedance of the liquid in the blood circuit; a normal state frequency characteristic storage unit that stores frequency characteristics of impedance in normal state according to the liquid flowing through the blood circuit; a liquid determination unit that compares the frequency characteristics of the impedance measured by the impedance measurement unit with the frequency characteristics of the impedance in a normal state stored in the normal state frequency characteristic storage unit and determines whether they match, the normal frequency characteristic storage unit stores, for each step of blood purification treatment, frequency characteristics of the impedance under normal conditions depending on the liquid flowing through the blood circuit in that step and whether or not the patient has been punctured; the liquid determination unit, when transitioning from any step to the next step of blood purification treatment, compares the frequency characteristics of the impedance measured by the impedance measurement unit with the frequency characteristics of the impedance in a normal state in the next step stored in the normal state frequency characteristic storage unit, and determines whether they match. Blood purification device.

2. a process transition restriction unit that restricts the start of the next process when the liquid determining unit determines that the liquids do not match, and that lifts the restriction on the start of the next process when the liquid determining unit determines that the liquids match; The blood purification device according to claim 1 .

3. the liquid determination unit makes a determination by utilizing the mutual correlation between a resistance component and a capacitance component that constitute the frequency characteristics of impedance. The blood purification device according to claim 1 .

4. The blood circuit includes: an arterial blood circuit having an arterial puncture needle attached to the tip thereof that can be inserted into a patient; a venous blood circuit having a venous puncture needle attached to the tip thereof, the venous puncture needle being capable of being inserted into a patient; The impedance measurement unit an arterial electrode provided in the arterial blood circuit; a venous electrode provided in the venous blood circuit; an oscillator that applies an AC voltage between the arterial electrode and the venous electrode and is capable of switching the frequency of the AC voltage; an impedance measuring device for measuring impedance for each frequency between the arterial electrode and the venous electrode, The blood purification device according to claim 1 .

5. a blood circuit for extracorporeally circulating the patient's blood; a blood purifier that is provided in the blood circuit and is capable of purifying blood; an impedance measuring unit capable of measuring the impedance of the liquid in the blood circuit at a predetermined frequency; a normal frequency characteristic storage unit that stores the impedance at the predetermined frequency under normal conditions according to the fluid flowing through the blood circuit; a liquid determination unit that compares the impedance at the predetermined frequency measured by the impedance measurement unit with the impedance at the predetermined frequency in a normal state stored in the normal state frequency characteristic storage unit, and determines whether they match; the normal frequency characteristic storage unit stores, for each step of blood purification treatment, the impedance at the predetermined frequency under normal conditions depending on the liquid flowing through the blood circuit during that step and whether or not the patient has been punctured; the liquid determination unit, when transitioning from any step to the next step of blood purification treatment, compares the impedance at the predetermined frequency measured by the impedance measurement unit with the impedance at the predetermined frequency in normal times in the next step stored in the normal frequency characteristic storage unit, and determines whether they match. Blood purification device.

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