Blood Purification Device

Abstract

To provide a blood purification device capable of calculating a blood circulation volume.SOLUTION: A blood purification device 100 comprises: a blood circuit 110; a blood purifier 120; concentration variation means which varies the concentration of circulating blood by water injection; a measurement part 115 which measures blood properties varying according to a blood concentration; and a control device 140. The control device 140 includes a blood circulation volume calculation unit 141 which calculates a blood circulation volume BV on the basis of a pre-water-injection measurement value Hctb and a post-water-injection measurement value Hcta measured by the measurement part 115, and a water injection quantity q.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a blood purification device capable of calculating circulating blood volume. [Background technology]

[0002] In blood purification therapy such as hemodialysis, which is applied to patients with chronic renal failure, the body's water and electrolytes are adjusted and waste products are removed. The accumulation of water in the body causes the patient to become overhydrated, and the excess water accumulates in the blood vessels, cells, and intercellular matrix. When fluid removal is started in treatment, excess fluid is first removed from the blood vessels, and then, following the reduction in intravascular fluid, interstitial fluid and intracellular fluid move, improving the overhydration of the entire body. This movement of excess fluid from outside the blood vessels into the blood vessels is called "plasma refilling." If the rate of fluid removal is greater than the rate of plasma refilling, the circulating blood volume will gradually decrease, and if the circulating blood volume decreases too much, symptoms such as low blood pressure and leg cramps may occur.

[0003] In order to prevent such symptoms, a method is used in which the occurrence of the above-mentioned symptoms is reduced by controlling the water removal speed based on the rate of change in circulating blood volume (see Patent Document 1). The rate of change in circulating blood volume is calculated based on the hematocrit value, which is an index of blood concentration. In general, the rate of change in circulating blood volume is considered to be within -15%, but the standard hematocrit value at the start of treatment varies depending on the patient's increase in fluid and weight gain or loss. In addition, depending on the patient, even if the rate of change in circulating blood volume is within -15%, symptoms such as a drop in blood pressure and lower limb cramps may occur, making it impossible to continue water removal, and there are also cases in which water removal can be continued without problems even if the rate of change exceeds -15%. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-154348 A Summary of the Invention [Problem to be solved by the invention]

[0005] As mentioned above, the target value for the rate of change in circulating blood volume cannot be determined uniformly and must be set appropriately for each patient and each treatment. To do this, it is necessary to determine the patient's circulating blood volume before treatment begins.

[0006] SUMMARY OF THE PRESENT DISCLOSURE ... It is therefore an object of the present invention to provide a blood purification device capable of calculating the circulating blood volume. [Means for solving the problem]

[0007] The present invention relates to a blood purification device comprising a blood circuit, a blood purifier provided in the blood circuit, a concentration changing means for changing the concentration of circulating blood by injecting or removing water from the blood circuit, a measurement unit disposed in the blood circuit for measuring blood properties that change according to the blood concentration, and a control device, wherein the control device comprises a circulating blood volume calculation unit for calculating the circulating blood volume based on the measured values ​​measured by the measurement unit before water injection or before water removal by the concentration changing means, the measured values ​​measured after water injection or after water removal, and the amount of water injected or removed by the concentration changing means.

[0008] In addition, it is preferable that the control device further includes a target value calculation unit that calculates a target value for the rate of change of circulating blood volume based on the circulating blood volume calculated by the circulating blood volume calculation unit and the patient's body weight before start of treatment.

[0009] In addition, the control device preferably performs a two-sided blood removal step of introducing blood from both the upstream and downstream sides of the blood circuit to fill the blood circuit with blood.

[0010] In addition, it is preferable that the blood purification device further includes a dialysis fluid circuit that supplies dialysis fluid to the blood purifier, the concentration changing means includes the blood purifier and the dialysis fluid circuit, and the control device injects dialysis fluid by back filtration through the blood purifier.

[0011] In addition, it is preferable that the blood purification device further comprises a dialysis fluid circuit that supplies dialysis fluid to the blood purifier, and a replenishment fluid line that injects dialysis fluid from the dialysis fluid circuit into the blood circuit upstream or downstream of the blood purifier, the concentration changing means includes the dialysis fluid circuit and the replenishment fluid line, and the control device injects a predetermined amount of water through the replenishment fluid line.

[0012] It is also preferable that the concentration changing means includes the blood purifier, and the control device removes a predetermined amount of water in the blood purifier. Effect of the Invention

[0013] According to the blood purification device of the present invention, the circulating blood volume can be calculated by increasing or decreasing the patient's circulating blood volume to change the blood concentration and measuring the blood properties before and after the change. [Brief description of the drawings]

[0014] [Figure 1] 1 is a diagram showing a schematic configuration of a blood purification device according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a block diagram of a blood purification device according to a first embodiment. [Diagram 3] FIG. 2 is an explanatory diagram of a blood removal process carried out in the blood purification apparatus. [Figure 4] FIG. 4 is an explanatory diagram of a method for changing blood concentration in the first embodiment. [Diagram 5] FIG. 13 is an explanatory diagram of a method for calculating a target value for the rate of change of circulating blood volume. [Figure 6] FIG. 11 is an explanatory diagram of a method for changing blood concentration in a modified example of the first embodiment. [Figure 7] FIG. 11 is an explanatory diagram of a method for changing blood concentration in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Preferred embodiments of the blood purification apparatus of the present invention will now be described with reference to the drawings. The blood purification device of the present invention purifies the blood of patients with renal failure or drug addiction, and also performs a dialysis process to remove excess water from the blood.The blood purification device of the present invention is an automatic blood purification device that automatically and continuously performs each process, such as a priming process, a blood removal process, a fluid replacement process, and a blood return process, by controlling the flow of the dialysis fluid in the blood circuit.

[0016] First Embodiment A first embodiment will be described in detail with reference to Figures 1 to 5. In the first embodiment, a case will be described in which injection of dialysis fluid by backfiltration is performed as a method for changing the blood concentration. FIG. 1 is a diagram showing a schematic configuration of a blood purification apparatus 100 according to a first embodiment of the present invention, and FIG.

[0017] As shown in FIG. 1, the blood purification device 100 includes a blood circuit 110, a measuring section 115, a blood purifier 120, a dialysate circuit 130, and a control device 140.

[0018] The blood circuit 110 has an arterial line 111, a venous line 112, a drug line 113, and a drain line 114. The arterial line 111, the venous line 112, the drug line 113, and the drain line 114 are all mainly made of soft tubes having flexibility through which liquid can flow.

[0019] One end of the arterial line 111 is connected to a blood inlet 122a of a blood purifier 120, which will be described later. The arterial line 111 is provided with an arterial connector 111a, an arterial bubble detector 111b, a blood pump 111c, and an arterial clamp 111d.

[0020] The arterial side connecting part 111a is disposed on the other end side of the arterial side line 111. A needle to be inserted into a patient's blood vessel is connected to the arterial side connecting part 111a. The arterial air bubble detector 111b detects the presence or absence of air bubbles in the tube. The blood pump 111c is disposed downstream of the arterial air bubble detector 111b in the arterial line 111. The blood pump 111c pumps out liquids such as blood and a priming solution inside the arterial line 111 by squeezing the tube constituting the arterial line 111 with a roller.

[0021] The arterial clamp 111d is disposed upstream of the arterial air bubble detector 111b. For example, when blood is returned via the arterial line 111, the arterial clamp 111d is controlled in response to the result of detection of air bubbles by the arterial air bubble detector 111b to open and close the flow path of the arterial line 111.

[0022] One end of the venous line 112 is connected to a blood outlet 122b of a blood purifier 120, which will be described later. The venous line 112 is provided with a venous connection part 112a, a venous air bubble detector 112b, a drip chamber 112c, and a venous clamp 112d.

[0023] Venous connecting part 112a is disposed on the other end side of venous line 112. A needle to be inserted into a patient's blood vessel is connected to venous connecting part 112a. The venous air bubble detector 112b detects the presence or absence of air bubbles in the tube. Drip chamber 112c is disposed upstream of venous air bubble detector 112b and stores a certain amount of blood in order to remove air bubbles and coagulated blood that have entered venous line 112 and to measure venous pressure.

[0024] The venous clamp 112d is disposed downstream of the venous air bubble detector 112b and is controlled in accordance with the result of the detection of air bubbles by the venous air bubble detector 112b to open and close the flow path of the venous line 112.

[0025] The drug line 113 supplies the drug required during hemodialysis to the arterial line 111. One end of the drug line 113 is connected to a drug pump 113a that pumps out the drug, and the other end is connected to the arterial line 111. The drug line 113 is also provided with a clamping means (not shown), and the flow path is closed by the clamping means except when the drug is being injected. In the first embodiment, the other end of the drug line 113 is connected to the arterial line 111 downstream of the blood pump 111c.

[0026] The drain line 114 is connected to the drip chamber 112c. A drain line clamp 114a is disposed on the drain line 114. The drain line 114 is a line for draining the priming solution in the priming step for washing and purifying the blood circuit 110 and the blood purifier 120.

[0027] The measurement unit 115 is a sensor for measuring blood properties that change depending on the concentration of blood taken from a patient. Specifically, blood properties include hematocrit value, hemoglobin value, electrical resistivity, etc. In each embodiment described in this specification, the hematocrit value is measured as an index of blood properties.

[0028] The measurement unit 115 may be located anywhere in the blood circuit 110, but is preferably located at a place that is less susceptible to effects immediately after a concentration change in the blood circuit 110. In this embodiment, since the dialysis fluid is injected by backfiltration in the blood purifier 120 described below, the measurement unit 115 is preferably located upstream of the blood purifier 120, and is located in the arterial line 111 near the blood inlet 122a of the blood purifier 120.

[0029] The blood purifier 120 includes a cylindrical container body 121 and a dialysis membrane (not shown) housed inside the container body 121. The inside of the container body 121 is partitioned by the dialysis membrane into a blood flow path and a dialysate flow path (neither shown). The container body 121 is provided with a blood inlet 122a and a blood outlet 122b communicating with the blood circuit 110, and a dialysate inlet 123a and a dialysate outlet 123b communicating with the dialysate circuit 130.

[0030] According to the above blood circuit 110 and blood purifier 120, blood taken out from the artery of a subject (dialysis patient) flows through the arterial line 111 by the blood pump 111c and is introduced into the blood side flow path of the blood purifier 120. The blood introduced into the blood purifier 120 is purified by the dialysis fluid flowing through the dialysis fluid circuit 130 described below via the dialysis membrane. The blood purified in the blood purifier 120 flows through the venous line 112 and is returned to the vein of the subject.

[0031] In the first embodiment, the dialysis fluid circuit 130 is configured by a so-called sealed volume control type dialysis fluid circuit 130. The dialysis fluid circuit 130 includes a dialysis fluid supply line 131a, a dialysis fluid drain line 131b, a dialysis fluid inlet line 132a, a dialysis fluid outlet line 132b, and a dialysis fluid delivery unit 133.

[0032] The dialysate delivery section 133 includes a dialysate chamber 1331 , a bypass line 1332 , and a water removal / backfiltration pump 1333 . The dialysis fluid chamber 1331 is composed of a hard container capable of storing a certain volume (for example, 300 mL to 500 mL) of dialysis fluid, and the inside of this container is partitioned by a soft diaphragm into a supply fluid storage section 1331a and a waste fluid storage section 1331b. The bypass line 1332 connects the dialysate outlet line 132b and the dialysate drain line 131b.

[0033] The water removal / back-filtration pump 1333 is disposed in the bypass line 1332. The water removal / back-filtration pump 1333 is configured by a pump that is driven to send the dialysis fluid inside the bypass line 1332 in a direction to flow the dialysis fluid to the dialysis fluid drain line 131b side (water removal direction) and in a direction to flow the dialysis fluid to the dialysis fluid outlet line 132b side (back-filtration direction).

[0034] The base end of the dialysate supply line 131a is connected to a dialysate supply device (not shown), and the tip end is connected to the dialysate chamber 1331. The dialysate supply line 131a supplies the dialysate to the dialysate supply storage section 1331a of the dialysate chamber 1331.

[0035] The dialysate introduction line 132a connects the dialysate chamber 1331 and the dialysate inlet 123a of the blood purifier 120, and introduces the dialysate contained in the liquid supply container 1331a of the dialysate chamber 1331 into the dialysate side flow path of the blood purifier 120.

[0036] The dialysate outlet line 132b connects the dialysate outlet 123b of the blood purifier 120 to the dialysate chamber 1331, and delivers the dialysate discharged from the blood purifier 120 to the waste fluid storage section 1331b of the dialysate chamber 1331.

[0037] The dialysate drain line 131b has a base end connected to the dialysate chamber 1331, and drains the drained dialysate contained in the drainage reservoir 1331b.

[0038] According to the above-described dialysis fluid circuit 130, by dividing the inside of the hard container constituting the dialysis fluid chamber 1331 with a soft diaphragm, the amount of dialysis fluid drawn out from the dialysis fluid chamber 1331 (the amount of dialysis fluid supplied to the fluid supply storage section 1331a) can be made equal to the amount of effluent collected in the dialysis fluid chamber 1331 (effluent storage section 1331b). As a result, when the water removal / backfiltration pump 1333 is stopped, the flow rate of the dialysis fluid introduced into the blood purifier 120 can be made equal to the amount of the dialysis fluid (discharge) discharged from the blood purifier 120. When the water removal / backfiltration pump 1333 is driven to send fluid in the water removal direction, a predetermined amount of water is removed from the blood at a predetermined speed in the blood purifier 120. When the water removal / backfiltration pump 1333 is driven to send fluid in the backfiltration direction, a predetermined amount of dialysis fluid is injected (backfiltered) into the blood circuit 110 in the blood purifier 120.

[0039] The control device 140 is configured by an information processing device (computer), and controls the operation of the blood purification apparatus 100 by executing a control program. The control device 140 controls the operation of various pumps, clamps, etc. arranged in the blood circuit 110 and the dialysis fluid circuit 130, and executes each process performed by the blood purification device 100, such as the priming process, blood removal process, dialysis process, fluid replacement process, blood return process, etc.

[0040] In the first embodiment, the control device 140 has a function to calculate the circulating blood volume of the patient and a function to calculate a target value of the rate of change of the circulating blood volume, in addition to the function to execute each of the above-mentioned steps. Specifically, the control device 140 calculates the circulating blood volume of the patient based on the hematocrit value before the dialysis fluid is injected into the blood circuit 110, the hematocrit value after the dialysis fluid is injected into the blood circuit 110, and the amount of the injected dialysis fluid, which are measured by the measurement unit 115. In addition, the control device 140 calculates a target value of the rate of change of the circulating blood volume based on the calculated circulating blood volume and the patient's body weight. To realize this function, the control device 140 includes a circulating blood volume calculation unit 141 and a target value calculation unit 142.

[0041] In the first embodiment, the operation of the blood purification apparatus 100 when calculating the circulating blood volume will be described with reference to Fig. 3 to Fig. 5. In the first embodiment, the calculation of the circulating blood volume by the circulating blood volume calculation unit 141 and the calculation of the target value of the rate of change of the circulating blood volume by the target value calculation unit 142 are performed after the blood removal step is completed and at the start of the dialysis step.

[0042] The blood removal step is a step of drawing the patient's blood from both the arterial connecting part 111a and the venous connecting part 112a after puncturing, thereby filling the arterial line 111 and the venous line 112 with blood.

[0043] In the blood removal process, as shown in FIG. 3, the arterial side connection portion 111a and the venous side connection portion 112a are each connected to a needle that will be inserted into the patient's blood vessel, the drainage line clamp 114a is in a closed state, and the arterial side clamp 111d and the venous side clamp 112d are in an open state.

[0044] The control device 140 supplies and discharges dialysis fluid from the dialysis fluid chamber 1331 at a flow rate of, for example, 500 mL / min, and drives the water removal / backfiltration pump 1333 to send the fluid in the water removal direction. When the flow rate of the water removal / backfiltration pump 1333 is set to 100 mL / min, the blood purifier 120 performs water removal at 100 mL / min. The blood pump 111c delivers blood from the arterial side connecting part 111a to the blood purifier 120 at a low flow rate of 40 to 50 mL / min. In this embodiment, the flow rate is set to 50 mL / min. Into the blood purifier 120, a priming solution and then blood flow at a flow rate of 50 mL / min from the blood inlet 122a, and the priming solution and then blood flow at a flow rate of 50 mL / min from the blood outlet 122b. The priming solution is also discharged from the dialysate outlet 123b. In this way, the inside of the blood purifier 120 and the inside of the blood circuit 110 are filled with blood.

[0045] In this state, the control device 140 (circulating blood volume calculation unit 141) supplies dialysis fluid from the dialysis fluid chamber 1331 at a flow rate of, for example, 500 mL / min, and the blood pump 111c pumps blood from the arterial side connection part 111a to the blood purifier 120 at a flow rate of, for example, 200 mL / min.

[0046] Here, the circulating blood volume calculation unit 141 measures the hematocrit value by the measurement unit 115 arranged near the blood inlet 122a in a state where blood is being sent from the arterial side connection unit 111a side to the blood purifier 120 side at a flow rate of, for example, 200 mL / min. This allows the hematocrit value to be measured before the dialysis fluid is injected into the blood circuit 110 (before the circulating blood is diluted).

[0047] Next, as shown in FIG. 4, the control device 140 operates the water removal / back-filtration pump 1333 so as to send a predetermined amount of water q (for example, 0.1 L) in the back-filtration direction. As a result, a predetermined amount q of dialysis fluid is injected by backfiltration into the blood purifier 120. In this manner, the predetermined amount q of dialysis fluid is injected into the blood purifier 120. That is, in the first embodiment, the blood purifier 120 and the dialysis fluid circuit 130 are used as concentration changing means for injecting water into the blood circuit 110.

[0048] The circulating blood volume calculation unit 141 measures the hematocrit value using the measurement unit 115 arranged near the blood inlet 122a when a predetermined time (e.g., one minute) has elapsed since the dialysis fluid was injected into the blood circuit 110. This measures the hematocrit value after a predetermined amount of q of dialysis fluid is injected into the patient's body and the patient's circulating blood is diluted. This predetermined time is set as the time until the dialysis fluid injected into the blood circuit 110 is returned and circulated inside the patient's body and the patient's circulating blood is diluted.

[0049] (Circulating blood volume calculation method) The hematocrit value before the concentration change measured by measurement unit 115 is Hctb (the measured value before the change), the hematocrit value after the concentration change is Hcta (the measured value after the change), and the patient's circulating blood volume before the concentration change (before treatment starts) is BV[L]. The circulating blood volume calculation unit 141 calculates the circulating blood volume BV[L] based on the measured value Hctb before the change, the measured value Hcta after the change, and a predetermined water injection volume q[L]. Specifically, since the volume of red blood cells does not change before and after the concentration change, the following formula (Equation 1) holds true.

number

number

[0050] Next, a specific method for calculating the target value of the rate of change in circulating blood volume will be described with reference to FIG.

[0051] (Calculation method for target value of ΔBV%) The dry weight of the patient when the body is properly hydrated is DW [kg], the patient's weight before the start of treatment is W [kg], and the circulating blood volume at the dry weight is BV 適 [L]: Excess fluid in the blood vessels before the start of treatment is measured using EV 内 The components of the patient's body weight at dry weight and before the start of treatment are shown in Fig. 5 using a bar graph. Here, it is assumed that the excess water before the start of treatment is present in the blood vessels.

[0052] Circulating blood volume at dry weight BV 適 is generally said to be about 1 / 13 of body weight, so BV 適 Therefore, the dry weight DW is converted to the circulating blood volume BV. 適 The weight excluding the above is 12BV. 適 Here, the conversion between body weight [kg] and volume [L] is performed assuming that the specific gravity of blood is 1.

[0053] The circulating blood volume BV[L] calculated by the circulating blood volume calculation unit 141 is calculated by dividing the circulating blood volume at the dry weight by BV 適 [L] and excess water in blood vessels before treatment EC 内 The dry weight DW can be expressed as the sum of [L] and the circulating blood volume BV 適 Weight excluding 12BV 適 is equal to the patient's weight before the start of treatment W minus the circulating blood volume before the start of treatment BV. Therefore, BV 適can be expressed by the following formula (Equation 3).

[0054]

number

[0055] Here, ΔBV% represents the rate of increase or decrease in circulating blood volume during treatment based on the circulating blood volume before the start of treatment. Therefore, the target value of ΔBV% is set to circulating blood volume at the end of treatment when BV 適 The target value of ΔBV% can be expressed by the formula (4).

[0056]

number

[0057] BV of formula (4) 適 By substituting formula (3) into the above, the target value of ΔBV% can be calculated using formula (5).

[0058]

number

[0059] From the above, it has been shown that the target value of ΔBV % can be calculated based on the patient's body weight W before the start of treatment and the circulating blood volume BV calculated by the circulating blood volume calculation unit 141. As mentioned above, the extravascular excess water before the start of treatment is not taken into account, so the BV calculated by the formula (3) 適 is the true BV when extravascular fluid is taken into account 適 In other words, the target value of the true ΔBV% is smaller than the target value of ΔBV% calculated by the formula (5). Therefore, if the water removal speed is controlled so that it does not fall below the target value of ΔBV% calculated by the formula (5), it is possible to reduce the occurrence of symptoms such as a drop in blood pressure and leg cramps caused by a decrease in circulating blood volume.

[0060] In reality, excess water outside the blood vessels moves into the blood vessels due to plasma refilling, so the circulating blood volume BV before the start of treatment will not be as calculated by formula (Math. 2). However, when the change in ΔBV% becomes proportional to the water removal rate, it is determined that the plasma refill rate has become 0, and the state immediately before the proportional state is reached becomes the dry weight state.

[0061] In this embodiment, the BV is calculated based on the patient's weight W before treatment. 適 In order to calculate the target values ​​for and ΔBV%, the blood removal method is preferably bilateral blood removal, in which priming solution is not injected into the patient's body before the start of treatment. When unilateral blood removal is used to inject a predetermined amount of priming solution PV into the patient's body before the start of treatment, the patient's weight W before the start of treatment must be replaced with W+PV, and the measured value of the blood property in a state in which the blood circuit 110 is filled with blood, that is, in a state in which the priming solution is injected into the patient's body and the patient's circulating blood is diluted, must be set as the measured value Hctb before the change.

[0062] The blood purification apparatus 100 of the first embodiment described above provides the following advantages.

[0063] (1) The blood purification device 100 includes a blood circuit 110, a blood purifier 120, a concentration changing means for increasing the circulating blood volume by injecting water into the blood circuit 110, a measurement unit 115 for measuring blood properties that change according to the blood concentration, and a circulating blood volume calculation unit 141 for calculating the circulating blood volume based on the measured value Hctb before water injection by the concentration changing means, the measured value Hcta after water injection, and the amount of water injected q by the concentration changing means, which are measured by the measurement unit 115. This makes it possible to measure the circulating blood volume BV.

[0064] (2) The control device 140 further includes a target value calculation unit 142 that calculates a target value of the rate of change in circulating blood volume ΔBV% based on the circulating blood volume BV calculated by the circulating blood volume calculation unit 141 and the patient's body weight W before the start of treatment. This makes it possible to calculate the target value of ΔBV%, so that by controlling the water removal speed so that it does not fall below the target value of ΔBV%, it is possible to reduce the occurrence of symptoms such as a drop in blood pressure and leg cramps caused by a decrease in circulating blood volume.

[0065] (3) The control device 140 was made to perform blood removal by bilateral blood removal, which introduces blood from both the upstream and downstream sides of the blood circuit 110 to fill the blood circuit 110 with blood. This makes it possible to calculate the circulating blood volume BV without correcting the patient's body weight W measured before the start of treatment, since no priming solution is injected into the patient's body before the start of treatment.

[0066] (4) The concentration changing means is configured to include a blood purifier 120 and a dialysis fluid circuit 130 that supplies dialysis fluid to the blood purifier 120, and the control device 140 is caused to inject dialysis fluid by backfiltration through the blood purifier 120. This makes it possible to easily change the concentration of the patient's circulating blood without the need for a medical professional to perform an operation such as injecting a predetermined amount of saline into the blood circuit.

[0067] <Modification of the first embodiment> Next, a blood purification apparatus 100A according to a modification of the first embodiment will be described with reference to FIG. The blood purification apparatus 100A according to the modification differs from the first embodiment in that it is provided with a replacement fluid line 150 and in the arrangement of the measurement section 115. Therefore, the same components as those described in the first embodiment are denoted by the same reference numerals and their explanations are omitted, and only the differences will be described.

[0068] 6, in this modification, the dialysis fluid is injected into the blood circuit 110 via the substitution fluid line 150. That is, in the blood purification device 100A according to the modification, the dialysis fluid circuit 130 and the substitution fluid line 150 are used as concentration changing means. In the modified example, the measurement unit 115 may be disposed anywhere in the blood circuit 110 as in the first embodiment, but is preferably disposed in a location that is less susceptible to the effects of a change in concentration in the blood circuit 110 immediately after the change. In the modified example, the dialysis fluid is injected into the blood circuit 110 via a replenishment fluid line 150, which will be described later. Therefore, in the case of a pre-dilution method in which the replenishment fluid line 150 is connected to the upstream side of the blood purifier 120, the measurement unit 115 is preferably disposed upstream of the connection between the replenishment fluid line 150 and the arterial line 111 as shown in FIG. 6. In the case of a post-dilution method in which the replenishment fluid line 150 is connected downstream of the blood purifier 120, the measurement unit 115 is preferably disposed upstream of the drip chamber 112c, which is the connection between the replenishment fluid line 150 and the venous line 112.

[0069] The substitution fluid line 150 is a line for directly injecting the dialysis fluid in the dialysis fluid circuit 130 into the blood circuit 110, and is mainly composed of a flexible soft tube through which the liquid can flow. As shown in Fig. 6, the upstream side of the substitution fluid line 150 is connected to the dialysis fluid introduction line 132a of the dialysis fluid circuit 130. The downstream side of the substitution fluid line 150 is connected to the downstream side of the blood pump 111c of the arterial side line 111 or to the drip chamber 112c. A substitution fluid pump 151 and a substitution fluid line clamp 152 are arranged in the substitution fluid line 150.

[0070] The replacement fluid pump 151 takes out the dialysis fluid from the dialysis fluid circuit 130 and sends it to the blood circuit 110 (the arterial line 111 or the venous line 112). When the water removal / back-filtration pump 1333 does not send fluid, the same amount of water as the dialysis fluid injected into the arterial line 111 or the venous line 112 via the replacement fluid line 150 is recovered by water removal in the blood purifier 120. When the injected dialysis fluid is sent to the patient's body (when fluid replacement is performed), the water removal / back-filtration pump 1333 is driven to send fluid in the back-filtration direction at the same flow rate as the replacement fluid pump 151. In this embodiment, the replacement fluid pump 151 is preferably a piston pump capable of sending fluid with high accuracy. The replenishment fluid line clamp 152 opens and closes the flow path of the replenishment fluid line 150 .

[0071] As in the case described in the first embodiment, after performing the blood removal process on both sides (see FIG. 3), the control device 140 (circulating blood volume calculation unit 141) supplies dialysis fluid from the dialysis fluid chamber 1331 at a flow rate of, for example, 500 mL / min, and the blood pump 111c pumps blood from the arterial side connection part 111a side to the blood purifier 120 side at a flow rate of, for example, 200 mL / min.

[0072] Here, the circulating blood volume calculation unit 141 measures the hematocrit value by the measurement unit 115 disposed near the downstream side of the blood pump 111c in a state where blood is being sent from the arterial side connection unit 111a side to the blood purifier 120 side at a flow rate of, for example, 200 mL / min. This allows the hematocrit value to be measured before the dialysis fluid is injected into the blood circuit 110 (before the circulating blood is diluted).

[0073] Next, as shown in FIG. 6, the control device 140 operates the water removal / back-filtration pump 1333 to send a predetermined water injection amount q (e.g., 0.1 L) in the back-filtration direction, and operates the replacement fluid pump 151 to send a predetermined water injection amount q. For example, the control device 140 operates the water removal / back-filtration pump 1333 in the back-filtration direction at a liquid injection amount of 100 mL / min for one minute, and operates the replacement fluid pump 151 at a liquid injection amount of 100 mL / min for one minute. As a result, a predetermined water injection amount q (e.g., 0.1 L) of dialysis fluid is injected into the arterial line 111 or the venous line 112 (drip chamber 112c) in the blood circuit 110. That is, in the modified example of the first embodiment, the dialysis fluid circuit 130 and the replacement fluid line 150 are used as concentration changing means for injecting water into the blood circuit 110.

[0074] The circulating blood volume calculation unit 141 measures the hematocrit value by the measurement unit 115 disposed near the downstream side of the blood pump 111c in a state in which the circulating blood of the patient is diluted by injecting the dialysis fluid into the blood circuit 110. This measures the hematocrit value after the circulating blood of the patient is diluted by injecting a predetermined injection volume q of the dialysis fluid into the patient's body.

[0075] In this embodiment, the concentration changing means is different from that described in the first embodiment, but the subsequent method of calculating the circulating blood volume and the method of calculating the target value of the rate of change of the circulating blood volume are similar to those described in the first embodiment, so their explanation will be omitted.

[0076] The blood purification apparatus 100A according to the modification of the first embodiment described above provides the following advantages in addition to the above-mentioned advantages (1) to (3).

[0077] (5) The blood purification device 100A further includes a dialysate circuit 130 and a replacement fluid line 150 for injecting dialysate to the upstream or downstream side of the blood purifier 120, and the concentration changing means includes the dialysate circuit 130 and the replacement fluid line 150. The control device 140 A predetermined amount of water q was injected into the blood circuit through the replacement fluid line 150. This makes it possible to easily change the concentration of the circulating blood of the patient without the need for a medical professional to perform an operation such as injecting a predetermined amount of physiological saline into the blood circuit.

[0078] <Second embodiment> Next, a blood purification apparatus 100 according to a second embodiment will be described with reference to FIG. The second embodiment differs from the first embodiment in that the circulating blood is concentrated by removing water, whereas the first embodiment and the modified example of the first embodiment dilute the circulating blood by injecting dialysis fluid to change the concentration. The blood purification device 100 is the same as that described in the first embodiment, and therefore the description will be omitted.

[0079] As in the case described in the first embodiment, after performing the blood removal process on both sides (see FIG. 3), the control device 140 (circulating blood volume calculation unit 141) supplies dialysis fluid from the dialysis fluid chamber 1331 at a flow rate of, for example, 500 mL / min, and the blood pump 111c pumps blood from the arterial side connection part 111a side to the blood purifier 120 side at a flow rate of, for example, 200 mL / min.

[0080] Here, the circulating blood volume calculation unit 141 measures the hematocrit value by the measurement unit 115 arranged near the blood inlet 122a in a state where blood is being sent from the arterial side connection unit 111a side to the blood purifier 120 side at a flow rate of, for example, 200 mL / min. This measures the hematocrit value before water is removed from the blood circuit 110 (before the circulating blood is concentrated).

[0081] Next, the control device 140 operates the water removal / backfiltration pump 1333 to send a predetermined amount of water removal q (e.g., 0.1 L) in the water removal direction, as shown in Fig. 7. This causes the blood purifier 120 to remove the predetermined amount of water removal q (e.g., 0.1 L). That is, in the second embodiment, the blood purifier 120 is used as a concentration changing means for removing water from the blood in the blood circuit 110.

[0082] The circulating blood volume calculation unit 141 measures the hematocrit value by the measurement unit 115 arranged near the blood inlet 122a in a state in which the circulating blood of the patient is concentrated by removing water in the blood circuit 110. This measures the hematocrit value after a predetermined amount of water q is removed from the patient's body and the circulating blood of the patient is concentrated.

[0083] (Circulating blood volume calculation method) As in the case described in the first embodiment, the hematocrit value before the concentration change measured by measurement unit 115 is defined as Hctb (the measured value before the change), the hematocrit value after the concentration change is defined as Hcta (the measured value after the change), and the patient's circulating blood volume before the concentration change (before treatment is started) is defined as BV[L]. The circulating blood volume calculation unit 141 calculates the circulating blood volume BV[L] based on the above-mentioned measured value Hctb before the change, the measured value Hcta after the change, and a predetermined amount of water removed q[L]. Specifically, since the volume of red blood cells does not change before and after the concentration change, the following formula (Equation 6) holds.

[0084]

number

[0085] From this, the circulating blood volume BV[L] can be calculated using formula (7).

[0086]

number

[0087] In this embodiment, the method of imparting a concentration change differs from that described in the first embodiment and its modified example. However, the method of calculating the target value of the rate of change in circulating blood volume thereafter is similar to that described in the first embodiment, and therefore will not be described again.

[0088] The blood purification apparatus 100 according to the second embodiment described above provides the following advantages in addition to the above-mentioned advantages (1) to (3).

[0089] (6) The concentration changing means is configured to include the blood purifier 120, and the control device 140 causes the blood purifier 120 to remove water at a predetermined amount q of water removal. This makes it possible to easily change the concentration of the circulating blood of the patient.

[0090] Although each preferred embodiment of the blood purification apparatus of the present invention has been described above, the present invention is not limited to the above-mentioned embodiments and can be modified as appropriate.

[0091] For example, in each of the above-mentioned embodiments, the blood purification device is configured to include a dialysis fluid circuit, but this is not limited to this. The concentration of the circulating blood may be changed by injecting physiological saline into the blood circuit, or water may be removed only by hemofiltration without dialysis. [Explanation of symbols]

[0092] 100, 100A Blood Purification Device 110 Blood circuit 111 Arterial line 111c Blood Pump 112 Venous Line 120 Blood Purifier 130 Dialysate circuit 133 Dialysate feeding section 140 Control device 141 Circulating blood volume calculation unit 142 ΔBV% target value calculation section 150 Refill Line 151 Replacement fluid pump

Claims

1. The blood circuit, a blood purifier provided in the blood circuit; A concentration changing means for changing the concentration of the circulating blood by injecting or removing water into or from the blood circuit; A measurement unit that is disposed in the blood circuit and measures blood properties that change depending on blood concentration; A blood purification device comprising: The control device includes: a circulating blood volume calculation unit that calculates a circulating blood volume based on a measurement value before water injection or water removal by the concentration changing means, a measurement value after water injection or water removal, and an amount of water injected or removed by the concentration changing means, the measurement unit being measured by the measurement unit; The control device is a blood purification device that performs a bilateral blood removal step of introducing blood from both the upstream and downstream sides of the blood circuit to fill the blood circuit with blood.

2. 2. The blood purification apparatus according to claim 1, wherein the control device further comprises a target value calculation unit that calculates a target value for a rate of change of the circulating blood volume based on the circulating blood volume calculated by the circulating blood volume calculation unit and the patient's body weight before initiation of treatment.

3. A dialysis fluid circuit for supplying a dialysis fluid to the blood purifier is further provided. the concentration changing means includes the blood purifier and the dialysis fluid circuit, 3. The blood purification apparatus according to claim 1, wherein the control device injects dialysis fluid through the blood purifier by backfiltration.

4. The blood purifier further includes a dialysis fluid circuit that supplies dialysis fluid to the blood purifier, and a replacement fluid line that injects dialysis fluid from the dialysis fluid circuit to the upstream or downstream side of the blood purifier in the blood circuit, the concentration changing means includes the dialysis fluid circuit and the substitution fluid line; 3. The blood purification apparatus according to claim 1, wherein the control device injects a predetermined amount of water through the replacement fluid line.

5. the concentration changing means includes the blood purifier, 3. The blood purification apparatus according to claim 1, wherein the control device performs water removal in the blood purifier at a predetermined amount.

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