Blood purification device

Abstract

Provided is a blood purification device capable of accurately calculating a circulating-blood volume change rate by taking into account a change in the proportion of the red blood cell component caused by treatment during blood purification therapy.　This blood purification device is for purifying blood of a patient by extracorporeal circulation of the blood through a blood circuit 1 having an arterial blood circuit 1a and a venous blood circuit 1b, the blood purification device comprising: a hematocrit sensor 5 that detects a hematocrit value indicating the concentration of blood flowing through the blood circuit 1; an input unit 9 through which a parameter related to a treatment that causes a change in a blood parameter during blood purification therapy is inputted; and a calculation unit 10 that calculates a circulating-blood volume change rate (ΔBV) on the basis of the hematocrit value detected by the hematocrit sensor 5 and the parameter inputted through the input unit 9.

Description

Blood purification device

[0001] The present invention relates to a blood purification device for purifying a patient's blood and performing blood purification therapy.

[0002] Dialysis treatment generally uses a blood circuit composed mainly of flexible tubes to circulate the patient's blood extracorporeally. This blood circuit mainly consists of an arterial blood circuit with an arterial puncture needle attached to the tip for collecting blood from the patient, and a venous blood circuit with a venous puncture needle attached to the tip for returning blood to the patient. A dialyzer is interposed between the arterial blood circuit and the venous blood circuit as a blood purifier.

[0003] In addition, a water removal pump is installed inside the dialysis device body to remove water from the patient's blood, and water removal is performed during dialysis treatment. The amount of water to be removed during water removal (water removal speed) is controlled by controlling the operation of the water removal pump. However, rapid or excessive water removal can excessively reduce the patient's circulating blood volume, which can lead to a drop in blood pressure or shock, while a slow water removal speed can extend the overall treatment time, placing a strain on the patient.

[0004] Therefore, technologies have been proposed to control the water removal rate while monitoring the patient's blood condition. In this prior art, parameters and indices indicating the patient's blood condition include the hematocrit value and the rate of change in circulating blood volume (ΔBV), as disclosed in, for example, Patent Document 1. The hematocrit value is a parameter indicating the concentration of blood, specifically, the volume ratio of red blood cells to whole blood. The rate of change in circulating blood volume is an index calculated based on the hematocrit value.

[0005] Japanese Patent Application Laid-Open No. 2007-143815

[0006] However, the above-mentioned conventional blood purification apparatuses have the following problems: During blood purification therapy, for example, when a patient is administered a transfusion of a red blood cell product, the proportion of red blood cells increases, resulting in an increase in hematocrit value. However, conventional calculation methods do not take into account changes in the proportion of red blood cells due to treatments such as transfusions, resulting in a decrease in the calculated circulating blood volume change (ΔBV), resulting in errors. Furthermore, when errors occur in the circulating blood volume change (ΔBV), similar errors also occur in other indices (e.g., plasma refill rate (PRR)) that are calculated using the circulating blood volume change (ΔBV) as a parameter.

[0007] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a blood purification device that can accurately calculate the rate of change in circulating blood volume, taking into account changes in the proportion of red blood cell components due to treatment during blood purification therapy.

[0008] A blood purification device according to one embodiment of the present invention is a blood purification device that purifies a patient's blood by extracorporeally circulating it through a blood circuit having an arterial blood circuit and a venous blood circuit, and is equipped with a detection unit that detects a hematocrit value indicating the concentration of blood flowing through the blood circuit, an input unit that inputs parameters related to treatments that affect blood parameters during blood purification treatment, and a calculation unit that calculates a rate of change in circulating blood volume based on the hematocrit value detected by the detection unit and the parameters input by the input unit.

[0009] According to the present invention, the rate of change in circulating blood volume is calculated based on the hematocrit value detected by the detection unit and the parameters input by the input unit, so that the rate of change in circulating blood volume can be calculated accurately taking into account changes in the proportion of red blood cell components due to treatment during blood purification therapy.

[0010] Schematic diagram showing a blood purification device according to an embodiment of the present invention. Block diagram showing the connections of the main parts of the blood purification device. Block diagram showing the calculation section of the blood purification device. Flowchart showing the control details of the blood purification device. Schematic diagram showing a method for estimating the circulating blood volume change rate and plasma refill rate by a blood purification device according to another embodiment of the present invention.

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The blood purification device according to this embodiment purifies a patient's blood by extracorporeally circulating the blood through a blood purifier and a blood circuit, thereby performing blood purification treatment (e.g., hemodialysis treatment). As shown in Fig. 1, the device comprises a hematocrit sensor 5 as a detector, a dialysis device main body 6, a control unit 8, an input unit 9, a calculation unit 10, a display unit 11, and a memory unit 12.

[0012] The blood circuit 1 attached to the dialysis device main body 6 comprises an arterial blood circuit 1a equipped with a blood pump 3 and a venous blood circuit 1b connected to an air trap chamber 4, with a dialyzer 2 serving as a blood purification unit connected between the arterial blood circuit 1a and the venous blood circuit 1b. Puncture needles are connected to the ends of the arterial blood circuit 1a and the venous blood circuit 1b, respectively, so that they can be inserted into the patient.

[0013] The dialyzer 2 has a housing formed with a blood inlet port 2a, a blood outlet port 2b, a dialysate inlet port 2c, and a dialysate outlet port 2d, of which the arterial blood circuit 1a is connected to the blood inlet port 2a, and the venous blood circuit 1b is connected to the blood outlet port 2b. The dialysate inlet port 2c and the dialysate outlet port 2d are connected to a dialysate inlet line L1 and a dialysate discharge line L2, respectively, which extend from the dialysis device main body 6.

[0014] Furthermore, a plurality of hollow fibers are housed within the dialyzer 2, the interior of which serves as a blood flow path, and the space between the outer circumferential surface of the hollow fibers and the inner circumferential surface of the housing serves as a dialysate flow path. The hollow fibers have numerous minute pores penetrating from their outer circumferential surface to their inner circumferential surface, forming hollow fiber membranes that allow impurities in the blood to pass through to the dialysate.

[0015] A hematocrit sensor 5 (detection unit) is connected to the arterial blood circuit 1a. The hematocrit sensor 5 includes a light-emitting element such as an LED and a light-receiving element such as a photodiode, and measures the hematocrit value, which indicates the concentration of the patient's blood flowing through the blood circuit 1, by irradiating the blood with light (e.g., near-infrared light of a predetermined wavelength) from the light-emitting element and receiving the transmitted or reflected light with the light-receiving element.

[0016] The dialysis device main body 6 includes a duplex pump P formed across the dialysate inlet line L1 and the effluent discharge line L2, and a water removal pump 7 connected to a bypass line in the effluent discharge line L2 that bypasses the duplex pump P. The distal end of the dialysate inlet line L1 is connected to the dialyzer 2 (dialysate inlet port 2c), and the proximal end is connected to a dialysate supply device (not shown) that prepares dialysate of a predetermined concentration.

[0017] The distal end of the waste fluid discharge line L2 is connected to the dialyzer 2 (dialysis fluid outlet port 2d), and the proximal end is connected to a waste fluid means (not shown). The dialysate supplied from the dialysate supply device passes through the dialysate introduction line L1 to the dialyzer 2, where it is purified and then sent to the waste fluid means through the waste fluid discharge line L2.

[0018] The ultrafiltration pump 7 is used to remove water from the patient's blood flowing through the dialyzer 2. That is, when the ultrafiltration pump 7 is driven, the volume of the liquid discharged from the waste fluid discharge line L2 becomes greater than the volume of dialysate introduced from the dialysate inlet line L1 because the duplex pump P is a metering pump, and water is removed (dehydrated) from the blood by the amount of the greater volume.

[0019] The blood collected from the arterial needle a by driving the blood pump 3 passes through the arterial blood circuit 1a to the dialyzer 2, where it is purified and dehydrated before being returned to the patient through the venous blood circuit 1b. In this embodiment, the dialysate is supplied and discharged by the duplex pump P, but other pumps (e.g., a chamber type) may be used instead.

[0020] Furthermore, the dialysis device main body 6 according to this embodiment has a control unit 8, an input unit 9, a calculation unit 10, a display unit 11, and a memory unit 12. The control unit 8 is composed of, for example, a microcomputer mounted on the dialysis device main body 6, and controls the driving of the blood pump 3, duplex pump P, and water removal pump 7, etc., and the opening and closing operations of the electromagnetic valves arranged in the dialysis device main body 6 during blood purification treatment.

[0021] The input unit 9 is used to input parameters related to treatments that change blood parameters during blood purification treatment (specifically, blood transfusions or fluid replacement for the patient, etc.) and parameters set during treatment, such as water removal rate.In this embodiment, the input unit 9 is connected to a blood transfusion device 13 for transfusing blood to patients undergoing blood purification treatment, a measuring device 14 for measuring the amount of bodily fluids excreted from the patient's body during blood purification treatment (amount of urination, bleeding, etc.), and an information storage unit 15 in which the patient's personal information, etc. is stored.

[0022] The transfusion device 13 administers a transfusion product to a patient, and outputs known parameters related to blood concentration, such as the amount of red blood cells contained in the transfusion product to be administered, and elapsed parameters related to the transfusion rate and transfusion time in real time, which are input to the input unit 9 of the dialysis machine main body 6. The measurement device 14 is configured with a drain or the like provided in, for example, an ICU (intensive care unit), and is capable of temporarily storing bodily fluids (urinary and bleeding) discharged from the patient's body and measuring the amount of bodily fluid discharge, with the measured values ​​output in real time and input to the input unit 9 of the dialysis machine main body 6.

[0023] The information storage unit 15 is composed of a server or the like that creates an electronic medical record into which personal data, including the patient's weight data before blood purification treatment, is input. In this embodiment, known parameters related to the patient's weight data stored in the information storage unit 15 are input to the input unit 9. The input unit 9 may automatically input parameters from the transfusion device 13, the measuring device 14, and the information storage unit 15, or the parameters may be input manually by an operator.

[0024] Calculation unit 10 is comprised of, for example, an arithmetic circuit, a microcomputer, etc., and is capable of calculating the circulating blood volume change rate (ΔBV) and the plasma refill rate (PRR) at regular time intervals based on the hematocrit value detected by hematocrit sensor 5 (detection unit) and parameters input via input unit 9. Specifically, as shown in Fig. 3, calculation unit 10 is configured to include a circulating blood volume change rate calculation unit 10a connected to input unit 9, a plasma refill rate calculation unit 10b connected to input unit 9, and an output unit 10c.

[0025] The circulating blood volume change rate calculation unit 10a comprises a calculation circuit and the like that calculates the circulating blood volume change rate (ΔBV) based on the parameters (known parameters and elapsed parameters) input via the input unit 9 and the hematocrit value detected by the hematocrit sensor 5. The plasma refilling rate calculation unit 10b comprises a calculation circuit and the like that calculates the plasma refilling rate (PRR) based on the parameters and water removal rate input via the input unit 9 and the circulating blood volume change rate (ΔBV) calculated by the circulating blood volume change rate calculation unit 10a. The output unit 10c outputs the circulating blood volume change rate (ΔBV) calculated by the circulating blood volume change rate calculation unit 10a and the plasma refilling rate (PRR) calculated by the plasma refilling rate calculation unit 10b to the display unit 11 and the memory unit 12.

[0026] If no treatment that changes blood parameters is performed during blood purification therapy, the rate of change in circulating blood volume (ΔBV) and plasma refill rate (PRR) are calculated using the following equations. Specifically, the rate of change in circulating blood volume (ΔBV) can be calculated using the following equation: (Ht at the start of dialysis - Ht at the time of measurement) / Ht at the time of measurement x 100. Furthermore, the plasma refill rate (PRR) can be calculated using the following equation: PRR = (amount of water removed during the measurement period + amount of change in circulating blood volume) / (time during the measurement period). The ratio of circulating blood volume to body weight is generally set to 1 / 13, but can be arbitrarily set by a medical professional such as a physician.

[0027] However, as the measured hematocrit value increases, ΔBV decreases, and if the ΔBV value decreases below a patient-specific value, it is said that there is a risk of hypotension or shock, and so ΔBV is used as an index showing the state of the patient during fluid removal (including not only fluid removal but also blood purification treatment in general). In this embodiment, the hematocrit value is used to calculate ΔBV (rate of change in circulating blood volume), which is used as an index showing the state of the patient.

[0028] When a procedure that changes blood parameters is performed during blood purification therapy (for example, a blood transfusion performed by the transfusion device 13 during blood purification therapy), known parameters related to the concentration of the blood transfused by the transfusion device 13, such as the hematocrit value or hemoglobin concentration of the transfusion product introduced into the patient's body, and elapsed parameters related to the transfusion rate and transfusion time by the transfusion device 13 are input to the input unit 9, and the calculation unit 10 performs the following calculation to calculate the rate of change in circulating blood volume (ΔBV). Note that it is assumed that ΔBV is calculated sequentially at regular intervals.

[0029] First, the hematocrit value (Htin (%)), transfusion rate (ml / min), and transfusion time (min) of the transfusion product are input to the input unit 9, and the amount of red blood cells (VRBCin (g)) administered to the patient is calculated using the following equation (1): VRBCin (g) = Transfusion rate (ml / min) × Transfusion time (min) × Htin (%) (1)

[0030] Next, the increase in hematocrit value (HtA (%)) due to transfusion is calculated using the following equation (2): HtA (%) = ((VRBCin (g) + VRBCpre (g)) / (BVpre (ml) + transfusion rate (ml / min) × transfusion time (min) - (VRBCpre (g) / BVpre (ml)) (2)

[0031] Then, ΔBVa (%), which excludes the expected increase in red blood cell volume due to transfusion, is calculated using the following equation (3): ΔBVa (%) = (Ht0 (%) / (Htt (%) - HtA (%)) - 1) × 100 (3)

[0032] Then, ΔBV (%) taking into account the blood transfusion is calculated using the following calculation formula (4): ΔBV (%) = ((ΔBVa (%) × patient's weight (kg) × 1 / 13) + (transfusion rate (ml / min) × time (min)) / BV0-1) × 100 (4)

[0033] where Htin: hematocrit value (%) of the administered blood product, VRBCin: amount of red blood cells (g) administered, VRBCpre (g): Htpre (%) (previously calculated Ht (%)) × BVpre (g) (previously calculated BV (g)), BVpre (%): patient's weight × 1 / 13 × previously calculated ΔBV (%), ΔBVa (%): ΔBV (%) with error due to increased red blood cells removed, BV0: patient's weight (kg) × 1 / 13 × ΔBV (%) at the start of treatment, Ht0: hematocrit value (%) at the start of treatment, Htt: hematocrit value at the time of measurement, HtA: expected increased hematocrit value (%) at the time of transfusion.

[0034] The hematocrit value (%) of the administered blood product may be calculated using the following formula (5): Htin (%) = Hbin (g / dl) × 3.3 (5) where Hbin is the hemoglobin concentration (g / dl) of the administered blood product.

[0035] Next, the calculation unit 10 calculates the plasma refill rate (PRR) using the circulating blood volume change rate (ΔBV) calculated by the above-mentioned equation (4) and parameters (parameters related to the amount of body fluid discharged from the patient's body during blood purification treatment and the water removal rate) input from the measurement device 14. That is, the input unit 9 according to this embodiment is configured to input parameters related to treatments that change blood parameters during blood purification treatment, as well as parameters related to the amount of body fluid discharged from the patient's body or the amount of fluid introduced into the body (infusion, replacement fluid, etc.) during blood purification treatment, and the water removal rate, and the calculation unit 10 calculates the plasma refill rate (PRR) based on the circulating blood volume change rate (ΔBV) and the parameters and water removal rate input by the input unit 9.

[0036] Plasma refilling refers to the process of maintaining circulating blood volume by transferring fluid from outside the blood vessels to inside the blood vessels in response to a decrease in circulating blood volume. The driving force behind this process is the difference in colloidal osmotic pressure and hydrostatic pressure inside and outside the blood vessels. The rate at which plasma refilling occurs is called the plasma refill rate (also called the plasma replenishment rate). If the rate at which the water removal pump 7 removes water is equal to the plasma refill rate, then theoretically, there will be no substantial change in the rate of change in circulating blood volume (ΔBV), and dialysis treatment will generally be performed with less strain on the patient.

[0037] The calculation unit 10 according to this embodiment calculates the plasma refill rate (PRR) using the following equation (6): PRR (l / h) = ((amount of water removed during the measurement period (ml)) + (amount of change in circulating blood during the measurement period (ml)) - (amount of infusion during the measurement period (ml)) - (amount of blood transfusion during the measurement period (ml)) + (amount of bleeding during the measurement period (ml)) + (amount of urine during the measurement period (ml))) / time of the measurement period (h) (6), where the measurement period is the time during which ΔBV is calculated sequentially.

[0038] The display unit 11 comprises a liquid crystal monitor or the like that displays the device settings and the patient's condition during blood purification treatment, and in this embodiment, displays in real time the circulating blood volume change rate (ΔBV) and plasma refill rate (PRR) calculated by the calculation unit 10. The storage unit 12 comprises a memory or the like that stores the circulating blood volume change rate (ΔBV) and plasma refill rate (PRR) calculated by the calculation unit 10.

[0039] 2, the display unit 11 according to this embodiment has an operation unit 11a, and the calculation unit 10 is connected to a switching unit S. The operation unit 11a is composed of a portion (such as input buttons displayed on the screen) displayed on a part of the screen of the display unit 11, which is made up of, for example, a touch panel, and a medical professional who visually recognizes the rate of change in circulating blood volume (ΔBV) or plasma refill rate (PRR) displayed on the screen can operate the duplex pump P, the blood pump 3, the ultrafiltration pump 7, etc. via the control unit 8 by operating the operation unit 11a. Note that the operation unit 11a may be a mechanical switch instead of an input button, etc. displayed on the screen of the display unit 11.

[0040] The switching unit S can be operated by an operator to switch input, and can switch between the display by the display unit 11 and the calculation by the calculation unit 10 at any timing. The switching unit S can be any unit that can be operated by an operator to input at any timing, and may be, for example, a switch unit displayed on a touch panel (including the display unit 11) similar to the operation unit 11a, or a mechanical switch.

[0041] Next, the control by the control unit 8 when a blood transfusion is performed as a procedure that changes blood parameters in the blood purification apparatus of this embodiment will be described with reference to the flowchart in Figure 4. First, in S1, known parameters related to the concentration of blood transfused by the transfusion device 13 (such as the hematocrit value of the transfusion product and the patient's weight before treatment) are input, and in S2, elapsed parameters related to the transfusion rate and transfusion time by the transfusion device 13 are input from the input unit 9. Then, upon input operation by the operator via the switching unit S, the process proceeds to S3, where the calculation unit 10 calculates ΔBVa by subtracting the increase in hematocrit value (HtA) due to the transfusion from the hematocrit value (Ht) detected by the hematocrit sensor 5, and adds the increase in blood volume due to the transfusion to calculate the circulating blood volume change rate (ΔBV).

[0042] Thereafter, the process proceeds to S4, where the circulating blood volume change rate (ΔBV) calculated by the calculation unit 10 is displayed on the display unit 11 and stored in the memory unit 12. Then, on the condition that the operator performs an input operation on the switching unit S, the process proceeds to S5, where the plasma refill rate (PRR) is calculated from the patient's weight before treatment, the circulating blood volume change rate (ΔBV) calculated in S3, and parameters input over time from the measurement device 14 to the input unit 9 (amount of urine excreted, bleeding, etc. from the patient), and the calculated plasma refill rate (PRR) is displayed on the display unit 11 and stored in the memory unit 12 in S6.

[0043] Although the present embodiment has been described above, the present invention is not limited thereto. For example, the treatment that changes blood parameters during blood purification treatment is not limited to infusion or fluid replacement, and other treatments may be used. Furthermore, other parameters may be used to calculate the rate of change of circulating blood volume (ΔBV) and the plasma refill rate (PRR).

[0044] 5, a blood purification apparatus according to another embodiment of the present invention may include an estimation unit 16 that uses a learning model (generative AI) that has undergone machine learning to estimate the circulating blood volume rate of change (ΔBV) and the plasma refill rate (PRR) based on the hematocrit value detected by the hematocrit sensor 5 (detection unit) and the parameters input to the input unit 9. Specifically, the estimation unit 16 accumulates multiple hematocrit values ​​detected by the hematocrit sensor 5 (detection unit) in past treatments, the parameters input to the input unit 9, and the circulating blood volume rate of change (ΔBV) and the plasma refill rate (PRR) calculated at that time to obtain accumulated data, and performs machine learning to estimate the circulating blood volume rate of change (ΔBV) and the plasma refill rate (PRR) using the accumulated data as training data, thereby obtaining a learning model.

[0045] Then, when input data (i.e., known parameters and progress parameters input to the input unit 9) in the current treatment is input to the input unit 9, the estimation unit 16 can estimate the rate of change in circulating blood volume (ΔBV) and the plasma refill rate (PRR) by using the learning model obtained by performing machine learning as described above. Machine learning refers to a technology related to artificial intelligence (generative AI) in which a computer learns large amounts of data and automatically constructs algorithms and models that perform tasks such as classification and prediction, and a neural network, for example, can be used as the technology or algorithm that enables machine learning.

[0046] A first embodiment of the present invention is a blood purification device that purifies a patient's blood by extracorporeally circulating it through a blood circuit 1 having an arterial blood circuit 1a and a venous blood circuit 1b, and includes a hematocrit sensor 5 (detection unit) that detects a hematocrit value indicating the concentration of blood flowing through the blood circuit 1, an input unit 9 that inputs parameters related to treatments that cause changes in blood parameters during blood purification treatment, and a calculation unit 10 that calculates a rate of change in circulating blood volume (ΔBV) based on the hematocrit value detected by the hematocrit sensor 5 and the parameters input by the input unit 9. As a result, the rate of change in circulating blood volume (ΔBV) is calculated based on the hematocrit value detected by the detection unit and the parameters input by the input unit, and therefore the rate of change in circulating blood volume (ΔBV) can be accurately calculated taking into account changes in the proportion of red blood cell components due to treatments during blood purification treatment.

[0047] In a second embodiment of the present invention, in the first embodiment, the treatment that changes the blood parameters is a blood transfusion or fluid replacement for the patient, thereby absorbing errors due to the blood transfusion or fluid replacement and enabling accurate calculation of the rate of change in circulating blood volume (ΔBV).

[0048] In a third embodiment of the present invention, the input unit 9 in the first embodiment is connected to a transfusion device 13 that transfuses blood into a patient during blood purification therapy, and known parameters related to the concentration of blood transfused by the transfusion device 13 and elapsed parameters related to the transfusion rate and transfusion time by the transfusion device 13 are input, and the rate of change in circulating blood volume (ΔBV) is calculated by the calculation unit 10. This makes it possible to accurately calculate the rate of change in circulating blood volume (ΔBV) even when transfusion is performed during blood purification therapy.

[0049] A fourth embodiment of the present invention is the same as the first embodiment, except that the input unit 9 receives input of parameters related to treatments that change blood parameters during blood purification treatment, as well as parameters related to the amount of body fluid discharged from the patient's body or the amount of fluid introduced into the body during blood purification treatment, and the water removal rate, and the calculation unit 10 calculates the plasma refill rate (PRR) based on the rate of change of circulating blood volume (ΔBV) and the parameters and water removal rate input by the input unit 9. This makes it possible to accurately calculate the plasma refill rate (PRR) taking into account changes in the proportion of red blood cell components due to treatments during blood purification treatment.

[0050] In a fifth embodiment of the present invention, in the fourth embodiment, the input unit 9 is connected to an information storage unit 15 into which personal data including the patient's weight data before blood purification treatment is input, and to a measuring device that measures the amount of body fluid excreted from the patient's body during blood purification treatment, and is also connected to known parameters related to the patient's weight data stored in the information storage unit 15, progress parameters related to the amount of body fluid measured by the measuring device 14, and the water removal rate, and the plasma refill rate (PRR) is calculated by the calculation unit 10. This allows the plasma refill rate (PRR) to be calculated with high accuracy.

[0051] The sixth embodiment of the present invention is the same as the first embodiment except that it includes an estimation unit 16 that uses a learning model that has undergone machine learning to estimate the rate of change in circulating blood volume based on the hematocrit value detected by hematocrit sensor 5 (detection unit) and parameters input to input unit 9. This makes it possible to accurately determine the rate of change in circulating blood volume by utilizing an artificial intelligence (AI) learning model.

[0052] The present invention can also be applied to devices with different external shapes or devices with additional functions, provided that they have the same gist as the present invention.

[0053] REFERENCE SIGNS LIST 1 Blood circuit 1a Arterial blood circuit 1b Venous blood circuit 2 Dialyzer 2a Blood inlet port 2b Blood outlet port 2c Dialysis fluid inlet port 2d Dialysis fluid outlet port 3 Blood pump 4 Air trap chamber 5 Hematocrit sensor (detection unit) 6 Dialysis device main body 7 Water removal pump 8 Control unit 9 Input unit 10 Calculation unit 11 Display unit 12 Memory unit 13 Blood transfusion device 14 Measuring device 15 Information memory unit 16 Estimation unit P Duplex pump L1 Dialysis fluid inlet line L2 Drainage discharge line

Claims

1. A blood purification device that purifies a patient's blood by circulating it extracorporeally through a blood circuit having an arterial blood circuit and a venous blood circuit, comprising: a detection unit that detects the hematocrit value, which indicates the concentration of blood flowing through the blood circuit; an input unit that inputs parameters related to treatments that cause changes in blood parameters during blood purification treatment; and a calculation unit that calculates the rate of change in circulating blood volume based on the hematocrit value detected by the detection unit and the parameters input by the input unit.

2. The blood purification apparatus according to claim 1, wherein the treatment that changes the blood parameters is a blood transfusion or fluid replacement for the patient.

3. A blood purification device as described in claim 1, wherein the input unit is connected to a transfusion device that transfuses blood into a patient during blood purification treatment, and receives input of known parameters related to the concentration of blood transfused by the transfusion device and elapsed parameters related to the transfusion rate and transfusion time by the transfusion device, and the calculation unit calculates the rate of change in circulating blood volume.

4. A blood purification device as described in claim 1, wherein the input unit receives input of parameters related to treatments that change blood parameters during blood purification treatment, as well as parameters related to the amount of body fluids discharged from the patient's body or the amount of fluids introduced into the body during blood purification treatment, and the water removal rate, and the calculation unit calculates the plasma refill rate based on the rate of change in circulating blood volume and the parameters and water removal rate input by the input unit.

5. A blood purification device as described in claim 4, wherein the input unit is connected to an information storage unit into which personal data including the patient's weight data before blood purification treatment is input, and to a measuring device that measures the amount of body fluids excreted from the patient's body during blood purification treatment, and to which known parameters related to the patient's weight data stored in the information storage unit, progress parameters related to the amount of body fluids measured by the measuring device, and the water removal rate are input, and the calculation unit calculates the plasma refill rate.

6. A blood purification device as described in claim 1, further comprising an estimation unit that uses a learning model that has undergone machine learning to estimate the rate of change in circulating blood volume based on the hematocrit value detected by the detection unit and parameters input to the input unit.

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