Blood purification device

Abstract

To provide a blood purification device capable of measuring a real blood flow rate by using one concentration measurement part while reducing over-concentration or an abrupt decrease in circulation blood amount.SOLUTION: A blood purification device 100 includes: a blood circuit 110; a blood purifier 120; water-pouring means of pouring water in the blood circuit 110; a measurement part 115 which is arranged at a position where blood concentration changes as water is poured by the water-pouring means in the blood circuit 110 and measures blood property that changes as blood concentration changes; and a controller 150. The controller 150 is provided with an actual blood flow rate calculation part 151 which calculates actual blood flow rate on the basis of measurement value before pouring water by the water-pouring means measured by the measurement part 115, measurement value after pouring water, and an amount of poured water by the water-pouring means.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a blood purification device capable of measuring actual blood flow rate. [Background technology]

[0002] In blood purification therapies such as hemodialysis, a roller-type tubing pump, which squeezes the tubing with rollers to pump blood, extracts blood from the patient's arteries, introduces it into a blood circuit, and sends it to a blood purifier. The purified blood is then returned to the patient's venous system via the blood circuit. A typical hemodialysis treatment takes approximately four hours. The indwelling needle used to extract blood during treatment is a foreign body to the body, creating an environment prone to blood clotting for extended periods. This can lead to gradual blockage of the blood circuit's flow path due to clotted blood. Furthermore, due to patient movement, the tip of the indwelling needle may come into contact with the vascular wall, preventing blood flow from being maintained. Even in such a situation, the tubing pump continues to operate at the set flow rate while the tubing is collapsed due to negative pressure. Therefore, a decrease in blood flow (poor blood removal) is difficult to detect through visual monitoring alone by medical staff.

[0003] Therefore, in order to detect poor blood removal, the actual blood flow rate (actual blood flow rate) in the blood circuit is measured. For example, Patent Document 1 describes a method in which the amount of water removed is temporarily increased to change the blood concentration, and the actual blood flow rate is measured from the change in concentration. Patent Document 2 describes a method in which two concentration measuring sensors are placed downstream of a blood purifier at a predetermined distance, the amount of water removed is temporarily increased to change the blood concentration, and the actual blood flow rate is measured using the time difference between when the concentration change is detected by the two concentration measuring sensors. Patent Document 3 describes a method in which two concentration measuring sensors are placed upstream and downstream of a blood purifier, and the actual blood flow rate is measured based on the measured blood concentration and the amount of water removed or the amount of water injected by backfiltration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5222706 [Patent Document 2] Patent No. 5237007 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-029882 Summary of the Invention [Problem to be solved by the invention]

[0005] The methods described in Patent Documents 1 and 2 above use a method of increasing the amount of water removed as a method of changing the concentration, which raises concerns about blood coagulation due to overconcentration of blood, and the occurrence of symptoms such as a drop in the patient's blood pressure and leg cramps due to a sudden drop in circulating blood volume. Furthermore, among the methods described in Patent Document 3, when changing the concentration by injecting dialysis fluid through backfiltration, the above-mentioned concerns do not arise, but two concentration measurement sensors must be prepared, which increases costs.

[0006] Therefore, an object of the present invention is to provide a blood purification device that can measure actual blood flow with a simpler configuration while reducing overconcentration and a sudden drop in 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 disposed in the blood circuit, a water injection means for injecting water into the blood circuit, a measurement unit disposed in a position in the blood circuit where the blood concentration changes due to water injection by the water injection means and for measuring blood properties that change depending on the blood concentration, and a control device, wherein the control device comprises an actual blood flow rate calculation unit that calculates an actual blood flow rate based on the measured values measured by the measurement unit before and after water injection by the water injection means and the amount of water injected by the water injection means.

[0008] The blood purification device further includes a dialysate circuit that supplies dialysate to the blood purifier, and a replenishment fluid line that injects dialysate from the dialysate circuit into the blood circuit upstream of the blood purifier, and the control device injects a predetermined amount of water through the replenishment fluid line, and the measuring unit is preferably located downstream of the connection between the blood circuit and the replenishment fluid line and upstream of the blood purifier.

[0009] Furthermore, it is preferable that the control device performs filtration in the blood purifier at a filtration volume corresponding to the predetermined water injection volume.

[0010] It is also preferable that the water injection means includes the blood purifier and a dialysate circuit that supplies dialysate to the blood purifier, and the measurement unit is disposed downstream of the blood purifier.

[0011] Furthermore, it is preferable that the blood purification device comprises a dialysate circuit that supplies dialysate to the blood purifier, and a replenishment fluid line that injects dialysate from the dialysate circuit into the blood circuit downstream of the blood purifier, the measurement unit being arranged in the blood circuit downstream of the blood purifier and upstream of the connection between the blood circuit and the replenishment fluid line, and the control device injects water at a predetermined injection volume through the replenishment fluid line and filters water from the blood purifier at a filtration volume corresponding to the predetermined injection volume. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a blood purification device that can measure actual blood flow rate with a simpler configuration while reducing overconcentration and a sudden decrease in circulating blood volume. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing a schematic configuration of a blood purification device according to a first embodiment of the present invention. [Figure 2] 1 is a block diagram showing a blood purification device according to a first embodiment. [Figure 3]FIG. 10 is a diagram showing a state before a change in blood concentration in the first embodiment. [Figure 4] FIG. 10 is a diagram showing a state after a change in blood concentration in the first embodiment. [Figure 5] FIG. 10 is a diagram showing a state before a change in blood concentration in a modified example of the first embodiment. [Figure 6] FIG. 10 is a diagram showing a state after a change in blood concentration in a modified example of the first embodiment. [Figure 7] FIG. 10 is a diagram showing a state before a change in blood concentration in the second embodiment. [Figure 8] FIG. 10 is a diagram showing a state after a change in blood concentration in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, preferred embodiments of the blood purification apparatus of the present invention will 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 of the processes, such as the priming process, blood removal process, dialysis process, fluid replacement process, and blood return process, by controlling the flow of dialysate in the blood circuit.

[0015] First Embodiment The first embodiment will be described in detail with reference to Figures 1 to 5. In the first embodiment, a case where a change in concentration is given to blood by injecting water will be described. FIG. 1 is a diagram showing the schematic configuration of a blood purification apparatus 100 according to a first embodiment of the present invention, and FIG. 2 is a block diagram of the blood purification apparatus 100. As shown in FIG.

[0016] The blood purification device 100 of the first embodiment purifies blood by performing hemodialysis and filtration in the blood purifier 120, and also performs online HDF, in which a portion of the dialysis fluid supplied to the blood purifier 120 is replenished (injected) into the blood before dialysis, and the same amount of replenishment (injected) is filtered. As shown in FIG. 1, the blood purification device 100 includes a blood circuit 110, a measuring unit 115, a blood purifier 120, a dialysate circuit 130, a substitution fluid line 140A, and a control device 150.

[0017] The blood circuit 110 includes 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 flexible soft tubes that allow liquid to flow through them.

[0018] 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.

[0019] The arterial connecting part 111a is disposed on the other end side of the arterial line 111. A needle to be inserted into the patient's blood vessel is connected to the arterial 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 priming solution inside the arterial line 111 by squeezing the tube that constitutes the arterial line 111 with a roller.

[0020] The arterial clamp 111d is disposed upstream of the arterial air bubble detector 111b and is controlled, for example, in accordance with the result of bubble detection by the arterial air bubble detector 111b to open and close the flow path of the arterial line 111.

[0021] One end of the venous line 112 is connected to a blood outlet 122b of the blood purifier 120, which will be described later. The venous line 112 is provided with a venous connector 112a, a venous air bubble detector 112b, a drip chamber 112c, and a venous clamp 112d.

[0022] Venous connector 112a is disposed at the other end of the venous line and is connected to a needle that is inserted into a patient's blood vessel. The venous air bubble detector 112b detects the presence or absence of air bubbles in the tube. Drip chamber 112c is located upstream of venous air bubble detector 112b and stores a certain amount of blood to remove air bubbles and coagulated blood that have entered venous line 112 and to measure venous pressure.

[0023] Venous clamp 112d is located downstream of venous air bubble detector 112b and is controlled in accordance with the result of air bubble detection by venous air bubble detector 112b to open and close the flow path of venous line 112.

[0024] Drug line 113 supplies a drug required during hemodialysis to arterial line 111. One end of drug line 113 is connected to drug pump 113a that delivers the drug, and the other end is connected to arterial line 111. Drug line 113 is also provided with clamping means (not shown), which keeps the flow path closed except when the drug is being injected. In the first embodiment, the other end of drug line 113 is connected to arterial line 111 downstream of blood pump 111c.

[0025] 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.

[0026] The measuring unit 115 is a sensor for measuring blood properties that change depending on the concentration of blood extracted from a patient, and is placed in a location in the blood circuit 110 where a change in concentration occurs due to water injection. Here, specific examples of 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 indicating blood properties.

[0027] In this embodiment, dialysate is injected from a substitution fluid line 140A (described later), and an amount of dialysate corresponding to the amount of injected dialysate is removed by a blood purifier 120 (described later). Therefore, the measurement unit 115 is disposed downstream of the connection between the substitution fluid line 140A and the arterial line 111 and upstream of the blood purifier 120. In this embodiment, the measurement unit 115 is disposed in the arterial line 111 near a blood inlet 122a of the blood purifier 120.

[0028] 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 of which are shown). The container body 121 is formed 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.

[0029] According to the above-described blood circuit 110 and blood purifier 120, blood extracted 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 flow path of the blood purifier 120. The blood introduced into the blood purifier 120 is purified by the dialysate flowing through the dialysate circuit 130, which will be described later, via a dialysis membrane. The blood purified in the blood purifier 120 flows through the venous line 112 and is returned to the subject's veins.

[0030] In the first embodiment, the dialysate circuit 130 is configured as a so-called sealed volume control type dialysate circuit 130. The dialysate circuit 130 includes a dialysate supply line 131a, a dialysate drain line 131b, a dialysate inlet line 132a, a dialysate outlet line 132b, and a dialysate delivery unit 133.

[0031] The dialysate delivery unit 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 holding a certain volume of dialysis fluid (for example, 300 mL to 500 mL), and the inside of this container is divided into a liquid supply storage section 1331a and a waste liquid storage section 1331b by a soft diaphragm. The bypass line 1332 connects the dialysate outlet line 132b and the dialysate drain line 131b.

[0032] 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 dialysate inside the bypass line 1332 in a direction to circulate the dialysate in the dialysate drain line 131b side (water removal direction) and in a direction to circulate the dialysate in the dialysate outlet line 132b side (back-filtration direction).

[0033] 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.

[0034] The dialysate introduction line 132a connects the dialysate chamber 1331 with 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.

[0035] The dialysate outlet line 132b connects the dialysate outlet 123b of the blood purifier 120 to the dialysate chamber 1331, and leads the dialysate discharged from the blood purifier 120 to the waste fluid storage section 1331b of the dialysate chamber 1331.

[0036] The base end of the dialysate drain line 131b is connected to the dialysate chamber 1331, and drains the dialysis fluid stored in the waste fluid storage portion 1331b.

[0037] According to the above-described dialysis fluid circuit 130, by dividing the interior 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 from 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 dialysis fluid (effluent) 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.

[0038] The substitution fluid line 140A is a line for directly injecting the dialysate in the dialysate 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. 1, the upstream side of the substitution fluid line 140A is connected to the dialysate introduction line 132a of the dialysate circuit 130. The downstream side of the substitution fluid line 140A is connected to the downstream side of the blood pump 111c of the arterial line 111. A substitution fluid pump 141 and a substitution fluid line clamp 142 are arranged on the substitution fluid line 140A.

[0039] The substitution fluid pump 141 extracts dialysate from the dialysate circuit 130 and sends it to the blood circuit 110 (arterial line 111). When the water removal / backfiltration pump 1333 is stopped, the same amount of water as the dialysate injected into the arterial line 111 via the substitution fluid line 140A is filtered in the blood purifier 120. When the injected dialysate is sent into the patient's body (when fluid replacement is performed), the substitution fluid pump 141 is driven to send the fluid in the backfiltration direction of the water removal / backfiltration pump 1333 at a predetermined replacement fluid flow rate. In this embodiment, the substitution fluid pump 141 is preferably a piston pump that can send fluid with high accuracy. The replacement fluid line clamp 142 opens and closes the flow path of the replacement fluid line 140A.

[0040] The control device 150 is configured by an information processing device (computer), and controls the operation of the blood purification device 100 by executing a control program. The control device 150 controls the operation of various pumps, clamps, etc. arranged in the blood circuit 110, the dialysate circuit 130, and the replacement fluid line 140A, and executes each process performed by the blood purification device 100, such as the priming process, blood removal process, dialysis process, fluid replacement process, and blood return process.

[0041] In the first embodiment, the control device 150 has a function of executing each of the above-mentioned steps, as well as a function of calculating an actual blood flow rate, which is the actual blood flow rate circulating through the blood circuit 110. Specifically, the control device 150 calculates the actual blood flow rate based on the hematocrit value measured by the measurement unit 115 before the dialysate is injected into the blood circuit 110, the hematocrit value after the dialysate is injected into the blood circuit 110, and the amount of the injected dialysate. To realize this function, the control device 150 includes an actual blood flow rate calculation unit 151.

[0042] In the first embodiment, the operation of the blood purification apparatus 100 when calculating the actual blood flow rate will be described with reference to Figures 3 and 4. In the first embodiment, the calculation of the actual blood flow rate by the actual blood flow rate calculation unit 151 is performed during the dialysis process or the fluid replacement process.

[0043] The dialysis process involves removing excess fluids and waste products from the patient. In the fluid replacement process, the patient's circulating blood volume is increased by injecting dialysate into the blood circuit 110. The fluid replacement process is performed as needed when symptoms such as a drop in blood pressure or cramps in the legs occur during the dialysis process, and can also be performed multiple times at regular intervals during the dialysis process in a planned manner to prevent a drop in blood pressure and improve peripheral circulation. In the first embodiment, the fluid replacement step is performed by a so-called pre-dilution method in which part of the dialysate flowing through the dialysate circuit 130 is injected into the arterial line 111 (blood circuit 110) through the substitution fluid line 140A.

[0044] In the dialysis process and fluid replacement process, the patient's blood introduced from the arterial side connection part 111a passes through the arterial side line 111, is purified in the blood purifier 120, and is returned to the patient from the venous side connection part 112a through the venous side line 112.

[0045] In addition, during the dialysis process and the fluid replacement process, as shown in Figures 3 and 4, the arterial side connection part 111a and the venous side connection part 112a are each connected to a needle that is inserted into the patient's blood vessel, the drainage line clamp 114a is in a closed state, and the venous side clamp 112d is in an open state.

[0046] In this state, as shown in FIG. 3, the control device 150 (actual blood flow rate calculation unit 151) calculates the Q A The dialysis fluid is supplied at a flow rate of (for example, 500 mL / min), and the water removal / backfiltration pump 1333 is operated in the water removal direction. R Operate the pump to deliver fluid at a rate of, for example, 10 mL / min.

[0047] Blood pump 111c is Q B The blood is sent from the arterial side connecting part 111a to the blood purifier 120 at a flow rate (for example, 200 mL / min). The blood purifier 120 has a blood inlet 122a through a blood B Blood flows in at a flow rate of Q R The blood is removed at a flow rate of Q B -Q R The dialysate inlet 123a is supplied with a flow rate of Q A The dialysate is introduced at a flow rate of Q A +Q R In this way, the dialysis waste is discharged at a flow rate of Q R Water removal is performed at a flow rate of

[0048] Here, the actual blood flow calculation unit 151 calculates Q B While blood is being sent from the arterial connection part 111a to the blood purifier 120 at a flow rate (for example, 200 mL / min), the hematocrit value is measured by the measuring part 115 disposed near the blood inlet 122a. This allows the hematocrit value to be measured before the dialysis fluid is injected into the blood circuit 110 (before dilution).

[0049] Next, the control device 150 drives the substitution fluid pump 141 in the state shown in Fig. 3. As a result, as shown in Fig. 4, the dialysis fluid is injected into the arterial line 111 through the substitution fluid line 140A at a predetermined injection rate q (for example, 20 mL / min). That is, in the first embodiment, the substitution fluid line 140A is used as a water injection means for injecting water into the blood circuit 110. The dialysis fluid inlet 123a is A The dialysate is introduced at a flow rate of -q, and Q is introduced from the dialysate outlet 123b. A +Q R In this way, in the fluid replacement process, the amount of water removed in the dialysis process Q R Q is calculated by adding the amount of water q injected into the blood circuit 110 via the replacement fluid line 140A. R Water removal is performed at a flow rate of +q.

[0050] Blood pump 111c is Q B The blood is sent from the arterial side connecting part 111a to the blood purifier 120 at a flow rate of (for example, 200 mL / min). B The blood flows in at a flow rate of +q. R +q, and the blood is removed from the blood outlet 122b at a flow rate of Q B -Q R is derived at a flow rate of

[0051] The actual blood flow calculation unit 151 calculates Q B The blood is sent from the arterial side connection part 111a side to the blood purifier 120 side at a flow rate of Q, and the dialysate is injected into the arterial side line 111 at a predetermined injection amount q.B While blood is being introduced from blood inlet 122a at a flow rate of +q, the hematocrit value is measured by measuring unit 115 disposed near blood inlet 122a, thereby measuring the hematocrit value after the dialysis fluid is injected into blood circuit 110 (after dilution).

[0052] Here, the hematocrit value before water injection measured by the measurement unit 115 is Hctb (measured value before change), the hematocrit value after water injection is Hcta (measured value after change), and the actual blood flow rate, which is the actual blood flow rate flowing through the blood circuit 110, is x [mL / min]. The actual blood flow rate calculation unit 151 calculates the actual blood flow rate x based on the measured value Hctb before the irrigation, the measured value Hcta after the irrigation, and the irrigation volume q. Specifically, since the volume of red blood cells does not change before and after the change in hematocrit value, the following formula (Equation 1) holds true.

[0053]

number

[0054] From this, the actual blood flow rate x can be calculated using the formula (Equation 2).

[0055]

number

[0056] The blood purification apparatus 100 of the first embodiment described above provides the following effects.

[0057] (1) The blood purification device 100 is configured to include a blood circuit 110, a blood purifier 120, a measurement unit 115 that measures blood properties that change depending on the blood concentration, a water injection means that injects water into the blood circuit, and an actual blood flow rate calculation unit 151 that calculates the actual blood flow rate based on the measured values before and after water injection by the water injection means measured by the measurement unit 115, and the amount of water injected by the water injection means. This makes it possible to measure the actual blood flow rate using a single measurement unit without causing overconcentration or a sudden decrease in circulating blood volume.

[0058] (2) The blood purification device 100 is configured to include a dialysate circuit 130 and a replenishment fluid line 140A for injecting dialysate upstream of the blood purifier 120, and the measurement unit 115 is located downstream of the connection between the blood circuit 110 and the replenishment fluid line 140A and upstream of the blood purifier 120. The control device 150 is also configured to inject a predetermined amount of water q through the replenishment fluid line 140A. This allows the concentration of blood flowing through the blood circuit 110 to be easily changed without the need for a medical professional to perform an operation such as injecting a predetermined amount of saline into the blood circuit. Furthermore, when performing pre-dilution hemodiafiltration treatment, the amount of water removed Q R While continuing water removal, the actual blood flow rate can be measured simply by increasing or decreasing the flow rate of the replacement fluid pump 141. It is also possible to measure the actual blood flow rate by utilizing the timing of rapid replacement fluid injection into the patient's body.

[0059] (3) The control device 150 performs filtration in the blood purifier 120 at a volume corresponding to the predetermined volume q of water injected. This allows the predetermined volume q to be increased, which in turn allows for greater changes in blood concentration, thereby improving the accuracy of measuring the actual blood flow rate.

[0060] <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 FIGS. The blood purification apparatus 100A according to the modification differs from the first embodiment in that it does not include a replacement fluid line and in the arrangement of the measurement unit 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.

[0061] 5, in this modification, the dialysate is injected by backfiltration via the blood purifier 120. That is, in the blood purification device 100A according to this modification, the dialysate circuit 130 and the blood purifier 120 are used as the water injection means. In this modification, measurement unit 115 is placed downstream of blood purifier 120. Specifically, measurement unit 115 is placed in venous line 112 near blood outlet 122b of blood purifier 120.

[0062] Next, a method for calculating the actual blood flow rate in a modified example of the first embodiment will be described.

[0063] (Actual blood flow calculation method) The blood purification device 100A uses the dialysate circuit 130 and the blood purifier 120 as a water injection means, and changes the concentration of blood flowing through the portion of the blood circuit 110 where the measuring unit 115 is located. Specifically, as shown in FIG. 5, first, the actual blood flow rate calculation unit 151 calculates the Q value when the water removal / backfiltration pump 1333 is stopped and the blood pump 111c is operated. B While blood is being pumped at this flow rate, the hematocrit value is measured by the measuring unit 115. This allows the hematocrit value before the dialysis fluid is injected into the blood circuit 110 (before dilution) to be measured.

[0064] Next, as shown in Fig. 6, the control device 150 drives the water removal / back-filtration pump 1333 in the back-filtration direction. B At the same time, reverse diafiltrate is injected into the blood circuit 110 via the blood purifier 120 at a predetermined injection rate q (for example, 20 mL / min).

[0065] The actual blood flow rate calculation unit 151 calculates the blood flow rate Q by the blood pump 111c. B The blood is delivered at a flow rate of q (for example, 20 mL / min) through the blood purifier 120, and the reverse diafiltrate is delivered to the blood circuit 110 at a predetermined flow rate q (for example, 20 mL / min). B While blood is being discharged at a flow rate of +q, the hematocrit value is measured by the measuring unit 115 disposed near the blood outlet 122b, thereby measuring the hematocrit value after the dialysis fluid is injected into the blood circuit 110 (after dilution).

[0066] In this modification, the water injection means is different from that described in the first embodiment, but the subsequent method of calculating the actual blood flow is the same as that described in the first embodiment, and therefore a description thereof will be omitted.

[0067] 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 advantage (1).

[0068] (4) The blood purification device 100A is configured to include a dialysate circuit 130 that supplies dialysate to the blood purifier 120, and the measurement unit 115 is located downstream of the blood purifier 120. The control device 150 then uses the dialysate circuit 130 and the blood purifier 120 as a water injection means to inject dialysate by backfiltration at a predetermined water injection volume q. This allows the concentration of blood flowing through the blood circuit 110 to be easily changed without the need for a medical professional to perform an operation such as injecting a predetermined amount of saline into the blood circuit. Furthermore, the actual blood flow rate can be measured by utilizing the timing of rapid fluid replacement, in which replacement fluid is injected into the patient's body.

[0069] Second Embodiment Next, a blood purification apparatus 100B according to a second embodiment will be described with reference to FIGS. The blood purification device 100B includes a blood circuit 110, a measuring unit 115, a blood purifier 120, a dialysate circuit 130, a substitution fluid line 140B, and a control device 150, and differs from the first embodiment in the destination of the substitution fluid line and the arrangement of the measuring unit 115. Furthermore, while the first embodiment and its modifications change the concentration by diluting the blood circulating through the blood circuit 110, the present embodiment changes the concentration by concentrating the blood circulating through the blood circuit 110. Components similar to those described in the first embodiment are designated by the same reference numerals and will not be described again, and only the differences will be described.

[0070] The substitution fluid line 140B is a line for directly injecting the dialysate in the dialysate circuit 130 into the blood circuit 110, and is mainly composed of a flexible soft tube through which a liquid can flow. As shown in Fig. 7, the upstream side of the substitution fluid line 140B is connected to the dialysate introduction line 132a of the dialysate circuit 130. The downstream side of the substitution fluid line 140B is connected to the drip chamber 112c arranged in the venous line 112.

[0071] A replenishment liquid pump 141 and a replenishment liquid line clamp 142 are disposed on the replenishment liquid line 140B. The substitution fluid pump 141 extracts dialysate from the dialysate circuit 130 and sends it to the blood circuit 110 (venous line 112). When the water removal / backfiltration pump 1333 is stopped, the same amount of water as the dialysate injected into the venous line 112 via the substitution fluid line 140B is recovered by filtration in the blood purifier 120. When the injected dialysate is sent into the patient's body (when fluid replacement is performed), the substitution fluid pump 141 drives the water removal / backfiltration pump 1333 to send fluid in the backfiltration direction at a predetermined replacement fluid flow rate. The replacement fluid line clamp 142 opens and closes the flow path of the replacement fluid line 140B.

[0072] 7, the measurement unit 115 is disposed at a location in the blood circuit 110 where a change in concentration occurs due to filtration. In the second embodiment, since filtration is performed by the blood purifier 120, the measurement unit 115 is disposed downstream of the blood purifier 120 and upstream of the connection between the venous line 112 and the replacement fluid line 140B. Specifically, the measurement unit 115 is disposed in the venous line 112 near the blood outlet 122b of the blood purifier 120.

[0073] Next, the operation of the blood purification apparatus 100B when calculating the actual blood flow rate in the second embodiment will be described with reference to Figures 7 and 8. In the second embodiment, the actual blood flow rate is calculated by the actual blood flow rate calculation unit 151 during the dialysis process or the fluid replacement process.

[0074] In the second embodiment, fluid replacement is performed by a so-called post-dilution method in which a portion of the dialysate flowing through the dialysate circuit 130 is injected into the venous line 112 (blood circuit 110) through a substitution fluid line 140B.

[0075] In the dialysis process and the fluid replacement process, as shown in Figures 7 and 8, the arterial side connection part 111a and the venous side connection part 112a are each connected to a needle that is inserted into the patient's blood vessel, the drainage line clamp 114a is in a closed state, and the venous side clamp 112d is in an open state.

[0076] In this state, the control device 150 (actual blood flow rate calculation unit 151) calculates the Q A The dialysis fluid is supplied at a flow rate of (for example, 500 mL / min), and the water removal / backfiltration pump 1333 is operated in the water removal direction. R (for example, 10 mL / min). R The water is removed. Blood pump 111c is Q B The blood is sent from the arterial side connecting part 111a to the blood purifier 120 at a flow rate (for example, 200 mL / min). The blood purifier 120 has a blood inlet 122a through a blood B Blood flows in at a flow rate of Q R The blood is removed at a flow rate of Q B -Q R The dialysate inlet 123a is supplied with a flow rate of Q A The dialysate is introduced at a flow rate of Q A +Q R In this way, the dialysis effluent is discharged at a flow rate of Q R Water removal is performed at a flow rate of

[0077] Here, the actual blood flow calculation unit 151 calculates Q B The blood is introduced into the blood purifier 121 from the arterial side connecting portion 111a at a flow rate of a predetermined amount of water removal Q R The blood is removed from the blood outlet 122b by Q B -Q RWhile blood is being discharged at this flow rate, the hematocrit value is measured by the measuring unit 115 disposed near the blood outlet 122b. This allows the hematocrit value to be measured before the dialysis fluid is injected into the blood circuit 110 (before concentration).

[0078] Next, the control device 150 drives the substitution fluid pump 141 in the state shown in Fig. 7. As a result, as shown in Fig. 8, the dialysate is injected into the venous line 112 through the substitution fluid line 140B at a predetermined injection rate q (for example, 20 mL / min). Also, the dialysate inlet 123a is supplied with Q A The dialysate is introduced at a flow rate of -q, and Q is introduced from the dialysate outlet 123b. A +Q R In this way, in the fluid replacement process, the amount of water removed in the dialysis process Q R Q is calculated by adding the amount of water q injected into the blood circuit 110 via the replacement fluid line 140B to the above. R Water removal is performed at a flow rate of +q. Blood pump 111c is Q B The blood is sent from the arterial side connecting part 111a to the blood purifier 120 at a flow rate (for example, 200 mL / min). The blood purifier 120 has a blood inlet 122a through a blood B Blood flows in at a flow rate of Q R +q, and the blood is removed from the blood outlet 122b at a flow rate of Q B -Q R -Derived at a flow rate of q.

[0079] The actual blood flow calculation unit 151 calculates Q B Blood is introduced into the blood purifier 120 from the arterial side connecting portion 111a at a flow rate of Q R The blood is removed at a flow rate of +q, and the blood is drawn out of the blood outlet 122b at a flow rate of Q B -Q R While blood is being discharged at a flow rate of -q, the hematocrit value is measured by the measuring unit 115 disposed near the blood outlet 122b, thereby measuring the hematocrit value after the dialysis fluid is injected into the blood circuit 110 (after concentration).

[0080] In this way, in the second embodiment in which fluid replacement is performed using the post-dilution method, the blood concentration during fluid replacement becomes higher than the blood concentration before the start of fluid replacement. That is, before and after fluid replacement, blood is concentrated downstream of the blood purifier 120 in the venous line 112 and upstream of the connection with the replacement fluid line 140B.

[0081] Here, the hematocrit value before the concentration change measured by the measurement unit 115 is Hctb (measured value before the change), the hematocrit value after the concentration change is Hcta (measured value after the change), and the actual blood flow rate, which is the actual blood flow rate flowing through the blood circuit 110, is x [mL / min]. The actual blood flow calculation unit 151 calculates the measured value Hctb before the change, the measured value Hcta after the change, and the amount of water removed Q R Based on +q, the actual blood flow rate x is calculated. Specifically, since the volume of red blood cells does not change before and after the concentration change, the following formula (Formula 3) holds true.

[0082]

number

[0083] From this, the actual blood flow rate x can be calculated using the formula (4).

[0084]

number

[0085] The blood purification apparatus 100B of the second embodiment described above provides the following advantages in addition to the above-mentioned advantage (1).

[0086] (5) The blood purification device 100B includes a dialysate circuit 130 and a replenishment fluid line 140B that injects dialysate downstream of the blood purifier 120. The measurement unit 115 is located downstream of the blood purifier 120 in the blood circuit 110 and upstream of the connection between the blood circuit 110 and the replenishment fluid line 140B. The control device 150 injects a predetermined amount of water q through the replenishment fluid line 140B, and the blood purifier 120 filters the blood at a filtration rate q corresponding to the predetermined amount of water q. This allows the actual blood flow rate to be measured using a single measurement unit 115 without causing overconcentration or a sudden decrease in circulating blood volume. The predetermined filtration rate q can be increased without overconcentrating the blood returned to the patient, allowing for larger changes in blood concentration, thereby improving the accuracy of measuring the actual blood flow rate. Furthermore, when performing post-dilution hemodiafiltration treatment, the amount of water removed Q R While continuing water removal, the actual blood flow rate can be measured simply by increasing or decreasing the flow rate of the replacement fluid pump 141.

[0087] 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-described embodiments and can be modified as appropriate.

[0088] For example, in each of the above-described embodiments, the blood purification device is configured to include a dialysate circuit, but this is not limiting. The blood concentration may be changed by injecting saline into the blood circuit, or by removing water only by hemofiltration without performing dialysis.

[0089] In the first embodiment, as shown in Fig. 4, when a predetermined amount of water is poured through the replacement fluid line 140A, a filtration amount q equivalent to the amount of dialysis fluid poured occurs in the blood purifier 120, but this is not limited to this. That is, when pouring water through the replacement fluid line 140A, the poured dialysis fluid may be infused into the patient's body as replacement fluid. In this case, the water removal / backfiltration pump 1333 may be caused to send fluid in the backfiltration direction at q equivalent to the amount of water poured q or a predetermined replacement fluid flow rate. [Explanation of symbols]

[0090] 100, 100A, 100B 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 140A, 140B Refill Lines 141 Replenisher pump 150 control device 151 Actual blood flow calculation section

Claims

1. The blood circuit, a blood purifier disposed in the blood circuit; a water injection means for injecting water into the blood circuit; a measuring unit disposed at a position in the blood circuit where the blood concentration changes due to the injection of water by the water injection means, for measuring blood properties that change depending on the blood concentration; a control device; a dialysate circuit for supplying dialysate to the blood purifier; a replacement fluid line for injecting dialysate from the dialysate circuit to the upstream side of the blood purifier in the blood circuit, The control device an actual blood flow rate calculation unit that calculates an actual blood flow rate based on the measured values before and after water injection by the water injection means, measured by the measurement unit, and the amount of water injected by the water injection means; Injecting a predetermined amount of water through the replenishment liquid line; The blood purification apparatus is arranged such that the measuring unit is located downstream of a connection between the blood circuit and the replacement fluid line and upstream of the blood purifier.

2. 2. The blood purification apparatus according to claim 1, wherein the control device performs filtration in the blood purifier at a filtration rate corresponding to the predetermined water injection rate.

3. A blood circuit; a blood purifier disposed in the blood circuit; a water injection means for injecting water into the blood circuit; a measuring unit disposed at a position in the blood circuit where the blood concentration changes due to the injection of water by the water injection means, for measuring blood properties that change depending on the blood concentration; A blood purification device comprising: the control device includes an actual blood flow rate calculation unit that calculates an actual blood flow rate based on the measured value before and after water injection by the water injection means measured by the measurement unit and the amount of water injected by the water injection means; the water injection means includes the blood purifier and a dialysis fluid circuit for supplying dialysis fluid to the blood purifier; The blood purification device, wherein the measurement unit is disposed downstream of the blood purifier.

4. A blood circuit; a blood purifier disposed in the blood circuit; a water injection means for injecting water into the blood circuit; a measuring unit disposed at a position in the blood circuit where the blood concentration changes due to the injection of water by the water injection means, for measuring blood properties that change depending on the blood concentration; a control device; a dialysate circuit for supplying dialysate to the blood purifier; a substitution fluid line for injecting dialysis fluid from the dialysis fluid circuit to a downstream side of the blood purifier in the blood circuit, the measuring unit is disposed in the blood circuit downstream of the blood purifier and upstream of a connection between the blood circuit and the replacement fluid line, The control device an actual blood flow rate calculation unit that calculates an actual blood flow rate based on the measured values before and after water injection by the water injection means, measured by the measurement unit, and the amount of water injected by the water injection means; A blood purification apparatus in which a predetermined amount of water is injected through the replacement fluid line, and a filtration amount corresponding to the predetermined amount of water is filtered from the blood purifier.

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