JP2024085569A - Blood Purification Device - Google Patents

Abstract

To provide a blood purification device capable of improving solute removal efficiency in a single needle method.SOLUTION: A blood purification device 100 includes a blood circuit 110, a blood purifier 120, a blood pump 111c, a dialysate circuit 130, a water removal/reverse filtration means 1333, and a control part 140. The control part 140 sets a blood removal amount in a blood removal process to 60-70% of internal volume of the blood purifier 120 and the blood circuit 110, drives the blood pump 111c in a normal rotation direction in the blood removal process, controls the water removal/reverse filtration means 1333 to send the dialysate in the water removal direction, and controls the blood pump 111c and the water removal/reverse filtration means 1333 so that a liquid feed speed of the blood pump 111c is higher than a liquid feed speed of the water removal/reverse filtration means 1333 in the water removal direction, then blood is caused to flow from a vein side line 112 into an artery side line 111 again in a branching part BP.SELECTED DRAWING: Figure 1

Description

The present invention relates to a blood purification device that alternates between blood removal and blood return using a single puncture needle.

One type of blood purification therapy is hemodialysis, which uses the so-called single-needle method, in which blood is removed and returned alternately using a single puncture needle. The single-needle method has many advantages, such as less pain for the patient and less strain on medical staff compared to when using two needles, as it only requires one puncture. Even if the needle is removed accidentally, less blood is lost.

However, in the commonly used single-needle method, blood is drawn and returned alternately, so the amount of blood circulating through the blood circuit and passing through the blood purifier is small, making it difficult to obtain sufficient dialysis efficiency (removal efficiency) for removing small molecular weight substances, especially relatively large molecular weight substances such as low molecular weight proteins. Therefore, it is not currently the first choice of treatment, and the single-needle method is suitable for elderly patients and patients who have just started dialysis, for example, when it is difficult to insert two normal indwelling needles due to underdeveloped vascular access, or for patients who are less active and do not require high dialysis efficiency (removal efficiency). In addition, the single-needle method is useful for home dialysis patients who can receive dialysis at any time depending on their physical condition, as dialysis is performed more frequently, but dialysis must be performed for a long time to increase dialysis efficiency (removal efficiency).

In the single-needle method, which performs hemodiafiltration with a single needle, a method has been proposed to increase dialysis efficiency (removal efficiency) by performing a circulation process between the blood removal process, in which blood is introduced into a part of the blood circuit by filtration, and the blood return process, in which dialysate is injected into a part of the blood circuit by backfiltration to return the blood, thereby ensuring a sufficient blood flow rate (see, for example, Patent Document 1).

Patent No. 4352775

In recent years, due to various factors such as improvements in the performance of blood purifiers, it has become clear through evaluation tests by the applicant that increasing the amount of blood processed (amount of contact) in a blood purifier through a circulation process as in Patent Document 1 does not promote removal of small molecular weight substances through diffusion. Therefore, it has been difficult to further improve the removal efficiency of solutes by increasing the amount of blood processed (amount of contact) in a blood purifier through a circulation process as in Patent Document 1.

Therefore, the present invention aims to provide a blood purification device that can improve the efficiency of solute removal using the single-needle method.

The present invention is a blood purification device that alternately removes and returns blood using a single puncture needle, comprising a blood circuit, a blood purifier disposed in the blood circuit, a blood pump disposed in the blood circuit and sending blood to the blood purifier, an arterial line connected to the upstream side of the blood purifier, a venous line connected to the downstream side of the blood purifier, a branch connected to the puncture needle, the branch connected to the upstream end of the arterial line and the downstream end of the venous line, a dialysis fluid circuit connected to the blood purifier and supplying dialysis fluid to the blood purifier, water removal/backfiltration means disposed in the dialysis fluid circuit and sending dialysis fluid so as to apply negative or positive pressure to the filtration membrane of the blood purifier, and a device for introducing blood into the blood circuit. and a control unit that controls the repeated treatment steps including a blood removal step in which blood is removed from the blood circuit and a blood return step in which blood is drawn from the blood circuit. The control unit sets the amount of blood removed in the blood removal step to be 60% to 70% of the internal volume of the blood purifier and the blood circuit, drives the blood pump in the forward direction in the blood removal step, controls the water removal/backfiltration means to send dialysis fluid in the water removal direction, and controls the blood pump and the water removal/backfiltration means so that the blood pump's sending speed is faster than the water removal direction sending speed of the water removal/backfiltration means, thereby causing blood to flow back into the arterial line from the branching section.

In addition, it is preferable that the control unit controls the blood pump and the water removal/backfiltration means so that the patient's blood concentration becomes a target blood concentration during the blood removal process.

It is also preferable that the control unit controls the blood pump and the water removal/backfiltration means to perform the blood return process after the blood removal process without performing a circulation process in which the operation of the water removal/backfiltration means is stopped to circulate blood through the blood circuit.

In addition, it is preferable that the control unit drives the blood pump in the forward rotation direction during the blood return process and controls the water removal/backfiltration means to send dialysis fluid in the backfiltration direction.

It is also preferable that the control unit controls the blood pump and the water removal/backfiltration means so that the amount of blood returned to the patient in the blood return process is less than the amount of blood removed from the patient in the blood removal process.

In addition, it is preferable that the control unit controls the blood pump and the water removal/backfiltration means to perform the next blood removal process after the blood return process without performing a circulation process in which the operation of the water removal/backfiltration means is stopped to circulate blood through the blood circuit.

In addition, it is preferable that, in the blood return process, the control unit withdraws blood using back-filtered dialysis fluid introduced from the blood purifier.

Furthermore, it is preferable that the blood circuit includes a fluid replacement line connected to the arterial line, and the control unit, in the blood return process, extracts blood using dialysis fluid introduced from the fluid replacement line.

The blood circuit preferably includes a fluid replacement line connected to the venous line, and the control unit preferably draws blood using dialysis fluid introduced from the fluid replacement line during the blood return process.

It is also preferable that the blood circuit includes a drug solution bag connected to the arterial line, and that the control unit, in the blood return process, draws blood using liquid introduced from the drug solution bag.

It is also preferable that the blood circuit includes a drug solution bag connected to the venous line, and that the control unit, in the blood return process, draws blood using liquid introduced from the drug solution bag.

The present invention provides a blood purification device that can increase the efficiency of solute removal using the single-needle method.

1 is a diagram showing a schematic configuration of a blood purification device according to a first embodiment of the present invention. 1 is a block diagram of a blood purification device according to a first embodiment. FIG. FIG. 4 is a diagram showing a blood removal step in the first embodiment. FIG. 4 is a diagram showing a blood returning process in the first embodiment. FIG. 4 is a diagram showing a schematic configuration of a blood purification device according to a second embodiment of the present invention. FIG. 11 is a diagram showing a schematic configuration of a blood purification device according to a third embodiment of the present invention. FIG. 11 is a diagram showing a schematic configuration of a blood purification device according to a fourth embodiment of the present invention.

Hereinafter, a preferred embodiment of the blood purification apparatus of the present invention will be described with reference to the drawings.
The blood purification device according to the first embodiment of the present invention is capable of performing blood purification by the so-called single-needle method, in which blood removal and blood return are performed alternately using a single puncture needle. Moreover, the blood purification device according to one embodiment of the present invention is an automatic blood purification device that automatically and continuously performs each step, such as the blood removal step and the blood return step, by controlling the flow of the dialysis fluid injecting/exporting from the blood circuit.

The first embodiment will be described in detail with reference to FIG. 1 and FIG.
The blood purification device 100 shown in FIG. 1 includes a blood circuit 110, a blood purifier 120 disposed in the blood circuit 110, a dialysate circuit 130, a control device 140 as a control unit, and a venous pressure sensor PS.

The blood circuit 110 has an arterial line 111, a venous line 112, and a drainage line 113. The arterial line 111, the venous line 112, and the drainage line 113 are all mainly made of soft tubes that are flexible enough to allow liquid to flow through them.

The arterial line 111 is connected to the upstream side of the blood purifier 120. One end of the arterial line 111 is connected to the blood inlet 122a of the blood purifier 120, which will be described later. The arterial line 111 is provided with an arterial connection part 111a, an arterial bubble detector 111b, and a blood pump 111c.

The arterial side connection part 111a is disposed at the other end of the arterial side line 111, and is connected to a single puncture needle SN that is inserted into the patient's blood vessel via a branch pipe BP (branch part) that is configured in a Y-shape or T-shape. In the branch pipe BP, the puncture needle SN is connected to the end BPa of the patient side branch part on the patient side of the Y-shape or T-shape three-way branch. In the branch pipe BP, the arterial side connection part 111a of the arterial side line 111 is connected to the arterial side end part BPb of the arterial side branch part that branches from the patient side branch part to the arterial side line 111, and the venous side connection part 112a (described later) of the venous side line 112 is connected to the venous side end part BPc of the venous side branch part that branches from the patient side branch part to the venous side line 112.

The arterial air bubble detector 111b detects the presence or absence of air bubbles in the tube.
The blood pump 111c sends blood to the blood circuit 110. 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 constituting the arterial line 111 with a roller. When the blood pump 111c is driven in the forward rotation direction, the blood and liquids such as priming solution flowing through the arterial line 111 are circulated in the direction from the blood pump 111c toward the blood purifier 120. When the blood pump 111c is driven in the reverse rotation direction, the blood and liquids such as priming solution flowing through the arterial line 111 are circulated in the direction from the blood purifier 120 toward the blood pump 111c.

The venous line 112 is connected to the downstream side of the blood purifier 120. 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 connection part 112a, a venous air bubble detector 112b, a drip chamber 112c, and a venous clamp 112d.
The venous connecting portion 112a is disposed on the other end side of the venous line, and is connected to the puncture needle SN via the branch pipe BP to which the arterial connecting portion 111a is connected.

The venous air bubble detector 112b detects the presence or absence of air bubbles in the tube.
The drip chamber 112c is disposed upstream of the venous air bubble detector 112b and stores a certain amount of blood or air in order to remove air bubbles and coagulated blood that have entered the venous line 112 and to measure the venous pressure.
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.

The drain line 113 is connected to the drip chamber 112c. A drain line clamp 113a is disposed on the drain line 113. The drain line 113 is a line for draining priming fluid during the priming process, which washes and purifies the blood circuit 110 and the blood purifier 120.

The blood purifier 120 comprises a cylindrical container body 121 and a dialysis membrane (filter membrane) (not shown) housed inside the container body 121, and 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 formed with a blood inlet 122a and a blood outlet 122b that communicate with the blood circuit 110, and a dialysate inlet 123a and a dialysate outlet 123b that communicate with the dialysate circuit 130.

The dialysis fluid circuit 130 is configured by a so-called sealed volume control type dialysis fluid circuit 130. The dialysis fluid circuit 130 is connected to the blood purifier 120 and supplies dialysis fluid to the blood purifier 120. The dialysis fluid circuit 130 includes a dialysis fluid supply line 131a, a dialysis fluid drain line 131b, a dialysis fluid introduction line 132a, a dialysis fluid discharge line 132b, and a dialysis fluid delivery section 133.

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

The water removal/backfiltration pump 1333 is disposed in the bypass line 1332. The water removal/backfiltration pump 1333 sends dialysis fluid so as to apply negative or positive pressure to the dialysis membrane of the blood purifier 120. The water removal/backfiltration pump 1333 is configured as a pump that can be driven to send the dialysis fluid inside the bypass line 1332 in a direction (water removal direction) to flow to the dialysis fluid drainage line 131b (direction to apply negative pressure to the dialysis membrane of the blood purifier 120) and in a direction (backfiltration direction) to flow to the dialysis fluid discharge line 132b (direction to apply positive pressure to the dialysis membrane of the blood purifier 120).

The base end of the dialysis fluid supply line 131a is connected to a dialysis fluid supply device (not shown) and the tip end is connected to the dialysis fluid chamber 1331. The dialysis fluid supply line 131a supplies dialysis fluid to the fluid supply storage section 1331a of the dialysis fluid chamber 1331.

The dialysis fluid introduction line 132a connects the dialysis fluid chamber 1331 to the dialysis fluid introduction port 123a of the blood purifier 120, and introduces the dialysis fluid contained in the fluid supply storage section 1331a of the dialysis fluid chamber 1331 into the dialysis fluid side flow path of the blood purifier 120.

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 discharged fluid storage section 1331b of the dialysate chamber 1331.

The base end of the dialysis fluid drain line 131b is connected to the dialysis fluid chamber 1331, and drains the dialysis fluid contained in the drainage fluid storage section 1331b.

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 separating membrane (diaphragm), it is possible to make 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) 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 (discharged fluid) 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 (filtered) 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.

The control device 140 is configured by an information processing device (computer), and controls the operation of the blood purification device 100 by executing a control program.
2, the control device 140 controls the operation of various pumps, clamps, and the like arranged in the blood circuit 110 and the dialysis fluid circuit 130 to execute various processes, such as a blood removal process and a blood return process, performed by the blood purification device 100. Specifically, the control device 140 controls the repeated execution of treatment processes including a blood removal process for introducing blood into the blood circuit 110 and a blood return process for withdrawing blood from the blood circuit 110.

The venous pressure sensor PS is connected to the drip chamber 112c. The venous pressure sensor PS detects the venous pressure, which is the pressure inside the drip chamber 112c.

Next, the treatment process in which blood removal and blood return are alternately repeated using the blood purification device 100 will be described with reference to Figures 3 and 4. The treatment process of this embodiment includes the blood removal process shown in Figure 3 and the blood return process shown in Figure 4.

Figure 3 shows the blood removal process. In the blood removal process of this embodiment, blood removed from the patient is introduced into the blood circuit 110, circulated through the arterial line 111, blood purifier 120, and venous line 112, and re-flows into the arterial line 111 at the branch pipe BP. The blood removal process in the first treatment process is performed after the priming process, and is performed with the blood circuit 110 filled with dialysis fluid as a priming fluid.

During the blood removal process, the control device 140 sets the amount of blood removed during the blood removal process to 60% to 70% (approximately 2/3) of the internal volume (priming volume) of the blood purifier 120 and blood circuit 110, drives the blood pump 111c in the forward direction, and controls the water removal/backfiltration pump 1333 to send dialysis fluid in the water removal direction.

In the blood removal process, the control device 140 controls the filtration (dehydration) speed of the water removal/backfiltration pump 1333 and the speed of the blood pump 111c. The control device 140 sets the speed of the blood pump 111c to be faster than the filtration speed of the water removal/backfiltration pump 1333, thereby filtering a portion of the blood from the patient and circulating the blood in the venous line 112 at a speed that is the difference between the speed of the blood pump 111c and the filtration speed of the water removal/backfiltration pump 1333.

By controlling the blood pump 111c and the water removal/backfiltration pump 1333 so that the blood pump 111c's delivery speed is faster than the water removal direction delivery speed of the water removal/backfiltration pump 1333, blood can be re-flowed from the venous line 112 to the arterial line 111 in the branch pipe BP during blood removal.

For example, in the blood removal process, the suitable blood removal speed through one puncture needle SN when the puncture needle SN size is 16 gauge (G) (outer diameter 1.6 mm) is about 200 mL/min. Therefore, as shown in FIG. 3, while introducing blood into the arterial line 111 and the blood purifier 120 at a blood removal speed of 200 mL/min, the blood pump 111c is driven in the forward direction at a faster liquid delivery speed (e.g., 500 mL/min) than the water removal/backfiltration pump 1333 (e.g., 200 mL/min in the water removal direction), and the water removal/backfiltration pump 1333 is driven in the water removal direction at, for example, 200 mL/min. This causes blood to flow through the venous line 112 at a speed (e.g., 300 mL/min) that is the difference between the speed of the blood pump 111c (e.g., 500 mL/min) and the filtration speed of the water removal/backfiltration pump 1333 (e.g., 200 mL/min in the water removal direction).

In the blood removal process, the control device 140 controls the blood pump 111c and the water removal/backfiltration pump 1333 so that the patient's blood concentration becomes the target blood concentration. The blood removal process is performed, for example, by placing a blood concentration sensor near the blood outlet 122b of the blood purifier 120 to monitor the hematocrit value, and the speed of the blood pump 111c and/or the water removal/backfiltration pump 1333 is adjusted so that the hematocrit value becomes a predetermined value. In this case, it is known that the viscosity of blood increases as the concentration increases, and that the viscosity increases rapidly especially when the hematocrit value exceeds 50%. Therefore, the increase in viscosity makes the dialysis membrane of the blood purifier 120 more likely to become clogged, leading to deterioration of the dialysis membrane and hemolysis. Therefore, it is preferable to concentrate the blood so that the hematocrit value does not exceed 50%.

For example, the filtration speed of the water removal/backfiltration pump 1333 is balanced with the speed of the blood pump 111c, but in the case where the hematocrit value of the blood concentration of a dialysis patient is 30%, it is preferable to set the upper limit of the hematocrit value by filtration to 50%. For example, when the size of the puncture needle SN is 16 gauge (G) (outer diameter 1.6 mm), the suitable blood removal speed is about 200 mL/min, so the maximum filtration speed of the water removal/backfiltration pump 1333 is 200 mL/min, and in order to filter blood with a hematocrit value of 30% at 200 mL/min to make the hematocrit value 50%, it is necessary to concentrate it to a hematocrit value of 50%/hematocrit value of 30%, or about 1.67 times.

Here, consider the relationship between the speed A (mL/min) of the blood pump 111c and the filtration speed B (mL/min) of the water removal/backfiltration pump 1333. If the speed difference between the speed A (mL/min) of the blood pump 111c and the filtration speed B (mL/min) of the water removal/backfiltration pump 1333 is X (mL/min), the following formula (1) holds.
A = B + X Formula (1)
In formula (1), the filtration rate B (mL/min) of the water removal/backfiltration pump 1333 is set to 200 (mL/min).

As described above, in order to filter blood with a hematocrit value of 30% at a filtration rate of 200 mL/min to reduce the hematocrit value to 50%, the blood needs to be concentrated to a value of about 1.67 times (hematocrit value 50%/hematocrit value 30%).
The relationship A×30%=X×50% holds, and rearranging this gives the following equation (2).
A / X = 1.67 ... formula (2)

From equations (1) and (2), the following equation (3) holds.
A = 1.67X = 200 (mL / min) + X ... formula (3)
From equation (3), X = 299 (mL/min) can be calculated.
Therefore, the speed A of the blood pump 111c is calculated by equation (1) as follows: A=B+X=200 (mL/min)+299 (mL/min)=approximately 500 (mL/min).
Based on the results of this calculation, in this embodiment, as an example, the filtration rate B of the water removal/backfiltration pump 1333 is set to 200 (mL/min) and the speed A of the blood pump 111c is set to 500 (mL/min).

In addition, since the internal volume (priming volume) of the blood purifier 120 and blood circuit 110 used in the evaluation test was approximately 220 mL, the amount of blood removed (filtered) was set to 150 mL (60% to 70% (approximately 2/3) of 220 mL). In that case, when filtering at a filtration speed of 200 (mL/min), the time for the blood removal process is (150/200) x 60 seconds = 45 seconds.

In addition, blood is withdrawn from the patient, filtered in the blood purifier 120, and then flows back into the arterial line 111 to the blood purifier 120 at a speed A of the blood pump 111c - filtration speed B of the water removal/backfiltration pump 1333 = 500 (mL/min) - 200 (mL/min) = 300 (mL/min). Therefore, the time it takes for blood to be discharged from the blood purifier 120 and reach the blood purifier 120 again is the internal volume (priming volume) of the blood purifier 120 and blood circuit 110 ÷ 300 (mL/min) × 60 seconds = (220/300) × 60 seconds = 44 seconds.

Therefore, the time for the blood removal process is 45 seconds, and the time for the blood to be discharged from the blood purifier 120 and reach the blood purifier 120 again is 44 seconds, which is almost the same time. As a result, the blood removal process (45 seconds) is almost completed by the time the blood is discharged from the blood purifier 120 and reaches the blood purifier 120 again (44 seconds), so the blood concentrated by filtration in the blood purifier 120 is prevented from being concentrated again in the blood purifier 120, and excessive concentration of the blood can be prevented.

In reality, the blood flowing into the blood purifier 120 is a mixture of blood drawn from the patient (hematocrit value 30%) and blood re-flowing from the venous line 112. In the blood return process described below, the control device 140 drives the blood pump 111c in the forward direction and controls the water removal/backfiltration pump 1333 to send dialysis fluid in the backfiltration direction. Therefore, when the blood removal process and the blood return process are alternately repeated, in the blood return process before the blood removal process, the blood in the blood circuit 110 is in a state where the blood is diluted with dialysis fluid, so the blood flowing into the blood purifier 120 has a hematocrit value lower than 30% immediately after the start of blood removal. As a result, when the blood concentrated to a hematocrit value of 50% in the blood purifier 120 flows into the arterial line 111, the hematocrit value is lower than 50%. The 1.67-fold concentration mentioned above includes a small margin, or allows for a little more concentration, and can prevent excessive concentration.

As described above, in the blood removal process, the patient's blood is introduced into the blood circuit 110 to remove blood, while the blood is re-flowed into the arterial line 111. As a result, in the blood removal process, blood can be re-flowed into the arterial line 111 while blood is being removed, so that a large amount of filtration is performed in the blood purifier 120 while blood is being removed, and large molecular weight substances such as low molecular weight proteins are mainly removed. Therefore, the efficiency of solute removal can be increased while preventing the blood from becoming excessively concentrated.

After the blood removal process is completed, the system moves to the next blood return process without performing the circulation process. Specifically, after the blood removal process, the control device 140 controls the blood pump 111c and the water removal/backfiltration pump 1333 to stop driving the water removal/backfiltration pump 1333 and perform the blood return process without performing the circulation process of circulating blood through the blood circuit 110.

In this embodiment, the reason why the circulation process is not performed after the end of the blood removal process will be explained. By passing the concentrated blood through the blood purifier 120 at the same time as blood removal, the efficiency of removing small molecular weight substances due to the diffusion effect is increased. In addition, the evaluation test has shown that the removal of small molecular weight substances does not increase significantly even if the circulation process is provided after the blood removal process. In addition, the reason why the removal of small molecular weight substances does not increase significantly is also thought to be due to the recent improvement in the performance of the blood purifier 120. In this way, in the evaluation test, it has been confirmed that the total amount of blood removed by filtration from the patient can be increased and the removal efficiency of large molecular weight substances can be increased by increasing the number of cycles of repeating the blood removal process and the blood return process without providing a circulation process after the blood removal process, rather than providing a circulation process after the blood removal process. In addition, since the circulation process is not performed, the blood concentrated in the blood removal process is not further circulated, so that excessive concentration of blood can be suppressed. For the above reasons, in this embodiment, after the end of the blood removal process, the circulation process is not performed and the process is moved to the next blood return process.

Figure 4 shows the blood return process. In the blood return process, the control device 140 drives the blood pump 111c in the forward direction and controls the water removal/backfiltration pump 1333 to send dialysis fluid in the backfiltration direction.

In the blood return process, basically, the same amount of blood as the amount of blood drawn is returned to the patient. However, in the blood return process, the risk of hemoconcentration, as in the blood withdrawal process, is low, so the speed and amount do not need to be set so strictly in consideration of the blood concentration. For example, in the blood return process, the blood pump 111c may be rotated in the reverse direction to return blood from the blood purifier 120 to the patient from both the arterial line 111 and the venous line 112, or the blood pump 111c may be rotated in the forward direction to return blood from the blood purifier 120 to the patient from the venous line 112.

For example, in the blood return process, the blood pump 111c is rotated in the forward direction to return blood to the patient, and during the blood return, blood is reflowed from the venous line 112 to the arterial line 111 as in the above-mentioned blood removal process, while returning blood to the patient from the venous line 112. In the blood return process, when the size of one puncture needle SN is, for example, 16 gauge (G) (outer diameter 1.6 mm), the upper limit of the blood return speed that is suitable is about 200 mL/min. Therefore, in this embodiment, as shown in FIG. 4, in the blood return process, the blood pump 111c is driven in the forward direction at a liquid delivery speed (for example, 200 mL/min). In addition, the water removal/backfiltration pump 1333 is driven in the backfiltration direction at, for example, 200 mL/min to deliver dialysis fluid so as to apply positive pressure to the dialysis membrane of the blood purifier 120.

In this case, blood is discharged at the outlet of the blood purifier 120 at 400 mL/min, and the blood that has passed through the venous line 112 is drawn out from the venous line 112 via a single puncture needle SN, and is returned to the patient at 200 mL/min in the branch pipe BP, while 200 mL/min re-flows into the arterial line 111.

After the blood return process is completed, the process moves to the next blood removal process without performing the circulation process. Specifically, the control device 140 controls the blood pump 111c and the water removal/backfiltration pump 1333 to perform the next blood removal process after the blood return process without performing the circulation process in which the water removal/backfiltration pump 1333 is stopped and blood is circulated through the blood circuit 110.

In this embodiment, the reason why the circulation process is not performed after the blood return process is explained. In the blood return process, the backfiltered dialysis fluid is flowed into the blood circuit 110, and the blood in the blood circuit 110 is pushed back toward the patient, so the blood is in a diluted state. Therefore, even if the circulation process is performed after the blood return process, the movement of substances due to the diffusion effect in the blood purifier 120 cannot be expected. Therefore, by performing as many cycles of the blood removal process and blood return process as possible without providing a circulation process after the blood return process, the total amount of blood removed from the patient can be increased, substances can be moved, and the efficiency of removing solutes can be further improved.

When performing the blood return process by rotating the blood pump 111c in the forward direction, the concentration of blood flowing through the arterial line 111 is relatively uniform. In contrast, a blood return process in which blood is returned by rotating the blood pump 111c in the reverse direction is possible. When performing the blood return process by rotating the blood pump 111c in the reverse direction, for example, when the blood pump 111c is driven in the reverse direction at, for example, 100 mL/min and the water removal/backfiltration pump 1333 is driven in the backfiltration direction at, for example, 200 mL/min, blood is returned from the blood purifier 120 through the venous line 112 at 100 mL/min and through the arterial line 111 at 100 mL/min. Therefore, the concentration of blood near the blood purifier 120 is low, and the concentration of blood near the puncture needle SN is high.

In this way, the blood return process in which the blood pump 111c is rotated in the forward direction to return blood has a more uniform blood concentration distribution in the blood circuit 110 than the blood return process in which the blood pump 111c is rotated in the reverse direction to return blood. In addition, when the blood pump 111c is rotated in the forward direction in the blood return process, the difference in concentration with the dialysis fluid at the time of transition to the next blood removal process is larger than when the blood pump 111c is rotated in the reverse direction, resulting in an advantageous diffusion effect.

When blood removal and blood return are alternately performed using one puncture needle SN as described above, in the blood removal process, blood is removed from the patient at 200 mL/min, while 300 mL/min is re-flowed into the arterial line 111. In the blood return process, blood is returned to the patient at 200 mL/min, while 200 mL/min is re-flowed into the arterial line 111. In this embodiment, the amount of blood removed in the blood removal process is 150 mL, and the amount of blood returned in the blood return process is 150 mL, and the amount of blood delivered in both processes is the same, but this is not limited to this.

For example, in the blood return process, the control device 140 can control the blood pump 111c and the water removal/backfiltration pump 1333 so that the amount of blood returned to the patient in the blood return process is less than the amount of blood removed from the patient in the blood removal process, taking into account the overall amount of water removed in the blood removal process and the blood return process.

In the dialysis using the single needle method of Patent Document 1, the cycle of the blood removal process, the circulation process after the blood removal process, the blood return process, and the circulation process after the blood return process is repeated multiple times. In this case, water removal is performed in the blood removal process, the circulation process after the blood removal process, and the circulation process after the blood return process. On the other hand, in this embodiment, the circulation process after the blood removal process and the circulation process after the blood return process are not provided, so water removal is performed only in the blood removal process. Here, when the blood removal process and the blood return process are performed, the time available for water removal is shorter than in the conventional case in which the blood removal process, the circulation process after the blood removal process, and the circulation process after the blood return process are performed, so the water removal speed is faster. When the water removal speed is faster, water removal is performed in a shorter time, so there is a possibility that symptoms such as a drop in blood pressure and lower limb cramps will occur more frequently.

In contrast, in the present invention, the amount of blood returned to the patient in the blood return process is set to be less than the amount of blood removed from the patient in the blood removal process. This allows the amount of water removed to be the difference between the amount of blood removed from the patient in the blood removal process and the amount of blood returned to the patient in the blood return process. Therefore, by adjusting the amount of blood returned in the blood return process to be less than the amount of blood removed in the blood removal process, the water removal speed can be slowed down by using the entire treatment time to remove water, even in the present invention in which water removal is performed only in the blood removal process. In this way, water removal can be performed using the entire treatment time, so that the water removal speed can be slowed down and substantial water removal (net water removal) can be performed compared to when water removal is performed only during the blood removal process. This is expected to reduce the frequency of symptoms such as low blood pressure and lower limb cramps.

By repeating the treatment steps of the blood removal process and blood return process described above, the blood is filtered while re-flowing in the blood removal process, thereby increasing the efficiency of solute removal and realizing the elimination of the circulation process after the blood removal process. In the blood return process, backfiltration is performed while re-flowing blood, and the circulation process is not performed after the blood return process. Furthermore, in the single-needle method of this embodiment, even if the circulation process is not performed after the blood removal process, a method is adopted in which the amount of blood returned to the patient in the blood return process is less than the amount of blood removed from the patient in the blood removal process to adjust the water removal speed. This makes it unnecessary to perform abrupt water removal, making it possible to suppress an increase in the water removal speed of the patient's actual water removal (net water removal).

The blood purification device 100 of this embodiment described above provides the following advantages:

(1) In a blood purification device 100 that alternately performs blood removal and blood return using a single puncture needle SN, the control device 140 sets the amount of blood removed in the blood removal process to 60% to 70% of the internal volume of the blood purifier 120 and blood circuit 110, drives the blood pump 111c in the forward direction in the blood removal process, controls the water removal/backfiltration pump 1333 to send dialysis fluid in the water removal direction, and controls the blood pump 111c and the water removal/backfiltration pump 1333 so that the liquid delivery speed of the blood pump 111c is faster than the liquid delivery speed in the water removal direction of the water removal/backfiltration pump 1333, thereby causing blood to reflow from the venous line 112 to the arterial line 111 at the branch point BP. As a result, in the blood removal process, blood is removed by introducing the patient's blood into the blood circuit 110, while the blood introduced in the blood removal process and the newly introduced blood are reflowed into the arterial line 111. This makes it possible to increase the efficiency of solute removal without performing a circulation process after the blood removal process. In addition, by setting the amount of blood removed during the blood removal process to 60% to 70% of the internal volume of the blood purifier 120 and blood circuit 110, excessive hemoconcentration can be prevented.

(2) The control device 140 controls the blood pump 111c and the water removal/backfiltration pump 1333 so that the patient's blood concentration becomes the target blood concentration during the blood removal process. This makes it possible to increase the efficiency of solute removal while preventing the blood concentration from becoming excessively high.

(3) The control device 140 controls the blood pump 111c and the water removal/backfiltration pump 1333 to perform the blood return process after the blood removal process, without performing the circulation process in which the water removal/backfiltration pump 1333 is stopped to circulate blood through the blood circuit 110. As a result, since it is not necessary to perform the circulation process after the blood removal process, the number of repeated cycles of the blood removal process and the blood return process can be increased, and the efficiency of solute removal can be further improved.

(4) In the blood return process, the control device 140 drives the blood pump 111c in the forward direction and controls the water removal/backfiltration pump 1333 to send dialysis fluid in the backfiltration direction. Here, if the blood pump 111c is driven in the reverse direction instead of the forward direction in the blood return process, the blood near the blood purifier 120 is thin and the blood near the puncture needle SN is thick and uneven. Therefore, by driving the blood pump 111c in the forward direction in the blood return process, the blood concentration distribution in the blood circuit 110 can be made more uniform than when the blood pump 111c is driven in the reverse direction.

(5) The control device 140 controls the blood pump 111c and the water removal/backfiltration pump 1333 so that the amount of blood returned to the patient in the blood return process is less than the amount of blood removed from the patient in the blood removal process, taking into account the total amount of water removed in the blood removal process and the blood return process. In this way, by adopting a method of adjusting the water removal speed in the blood removal process and the blood return process for removing water from the patient, it is not necessary to perform sudden water removal. Therefore, since the water removal is performed using the entire treatment time, it is possible to perform substantial water removal (net water removal) by slowing down the water removal speed compared to when water removal is performed only during the blood removal process. It is possible to suppress an increase in the (net) water removal speed of the patient. Therefore, it is expected that the frequency of occurrence of symptoms such as a drop in blood pressure and lower limb cramps can be reduced.

(6) The control device 140 controls the blood pump 111c and the water removal/backfiltration pump 1333 to perform the next blood removal process after the blood return process, without performing the circulation process in which the water removal/backfiltration pump 1333 is stopped to circulate blood through the blood circuit 110. As a result, since it is not necessary to perform the circulation process after the blood return process, the number of repeated cycles of the blood removal process and the blood return process can be increased, and the efficiency of solute removal can be further improved.

Next, a second embodiment will be described with reference to Fig. 5. Components similar to those described in the first embodiment are given the same reference numerals and description thereof will be omitted.
The dialysis fluid delivery section 133 of the blood purification device 100 according to the first embodiment is provided with a dialysis fluid chamber 1331, a bypass line 1332, and a water removal/backfiltration pump 1333, and the water removal/backfiltration pump 1333 is configured as a water removal/backfiltration means. However, the dialysis fluid delivery section 133 may be configured with only the dialysis fluid chamber 1331A, without the bypass line 1332 and the water removal/backfiltration pump 1333.

In the second embodiment, the dialysis fluid chamber 1331A can function as a water removal/backfiltration means that can change the balance of the supply/discharge of the dialysis fluid, without requiring the bypass line 1332 and the water removal/backfiltration pump 1333 of the first embodiment. In other words, the water removal/backfiltration means may be configured to include the dialysis fluid chamber 1331, the bypass line 1332, and the water removal/backfiltration pump 1333 as in the first embodiment, or the dialysis fluid chamber 1331A may be configured as a water removal/backfiltration means that can change the balance of the supply/discharge of the dialysis fluid, without providing the bypass line 1332 and the water removal/backfiltration pump 1333 as in the second embodiment.

Next, a third embodiment will be described with reference to Fig. 6. The same components as those described in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted.
The blood purification apparatus 100B according to the third embodiment includes a substitution fluid line 151a (fluid replacement line) and a substitution fluid pump 151b (fluid replacement pump) in addition to the components of the blood purification apparatus 100 according to the first embodiment. Specifically, the blood purification apparatus 100B shown in Fig. 6 includes a blood circuit 110, a blood purifier 120, a dialysis fluid circuit 130, a control device 140 as a control unit, the substitution fluid line 151a, the substitution fluid pump 151b, and a venous pressure sensor PS.

The substitution fluid line 151a is a line for directly injecting the dialysis fluid in the dialysis fluid circuit 130 used as a substitution fluid supply source into the blood circuit 110 as a substitution fluid (replacement fluid), and is mainly composed of a soft tube having flexibility through which liquid can flow. As shown in FIG. 6, the upstream side of the substitution fluid line 151a is connected to the dialysis fluid introduction line 132a of the dialysis fluid circuit 130. The downstream side of the substitution fluid line 151a is connected to the arterial side line 111, which is upstream of the blood purifier 120, in the case of the pre-dilution method, and is connected to the venous side line 112, which is downstream of the blood purifier 120, in the case of the post-dilution method.

The substitution fluid pump 151b is disposed in the substitution fluid line 151a, and extracts dialysis fluid as a substitution fluid (replacement fluid) from the dialysis fluid circuit 130 (substitution fluid supply source) and sends it to the blood circuit 110 (arterial line 111 or venous line 112).

The treatment process of the third embodiment includes a blood removal process and a blood return process. The blood removal process is the same as that described in the first embodiment, so a description thereof will be omitted and only the blood return process will be described. As an example of the blood return process, a one-sided blood return process will be described.

Figure 6 shows the one-sided blood return process. In the one-sided blood return process of this embodiment, in the case of the pre-dilution method, the blood pump 111c is stopped, the venous side clamp 112d is opened, the water removal/backfiltration pump 1333 is driven in the backfiltration direction at a predetermined flow rate (e.g., 60 ml/min), and the substitution fluid pump 151b is driven at the same flow rate as the water removal/backfiltration pump 1333. In this way, various pumps and clamps are controlled to inject dialysis fluid (substitution fluid, replacement fluid) into the blood circuit 110 via the substitution fluid line 151a. As a result, in the one-sided blood return process, the control device 140 uses the dialysis fluid introduced from the substitution fluid line 151a to extract blood from the venous side line 112 through one puncture needle SN, and returns the blood to the patient. For example, if the internal volume (priming volume) of the venous line 112 and the blood purifier 120 is about 100 ml, it takes about 1.7 minutes for the injected dialysis fluid to reach the vicinity of the puncture needle SN. After the blood return is completed, the process moves to the next blood removal process. The arterial line 111 that was not used for blood return is filled with concentrated blood.

In this embodiment, the venous line 112 is used as an example of a one-sided blood return process, but the blood pump 111c may be driven in the reverse direction at the same flow rate as the water removal/backfiltration pump 1333 to return blood using the arterial line 111. In addition, in this embodiment, the dialysis fluid (substitution fluid) is injected into the blood circuit 110 via the substitution fluid line 151a to return blood, but the blood purifier 120 may inject backfiltration dialysis fluid to return blood.

According to the blood purification apparatus 100B of the third embodiment described above, in addition to the above-mentioned effects (1) and (2), the following effect is achieved.
(7) In the blood purification apparatus 100B in which blood removal and blood return are alternately performed using a single puncture needle SN, the blood return step can also be performed by online hemofiltration therapy.

The fourth embodiment will be described with reference to Fig. 7. Configurations similar to those described in the first and third embodiments are given the same reference numerals and descriptions thereof will be omitted.
The blood purification apparatus 100C according to the fourth embodiment includes, in addition to the components of the blood purification apparatus 100B according to the third embodiment, a substitution fluid supply source 152. Specifically, the blood purification apparatus 100C shown in Fig. 7 includes a blood circuit 110, a blood purifier 120, a dialysis fluid circuit 130, a control device 140 as a control unit, a substitution fluid line 151a, a substitution fluid pump 151b, a substitution fluid supply source 152, and a venous pressure sensor PS.

A substitution fluid bag (medicinal fluid bag) filled with a substitution fluid (dialysis fluid or saline as a medicinal fluid) is used as the substitution fluid supply source 152. The upstream side of the substitution fluid line 151a is connected to the substitution fluid supply source 152. As in the third embodiment, the substitution fluid supply source 152 is connected to the arterial side line 111, which is upstream of the blood purifier 120, via the substitution fluid line 151a in the case of the pre-dilution method, and is connected to the venous side line 112, which is downstream of the blood purifier 120, in the case of the post-dilution method.

The blood removal process of the treatment process that is repeatedly performed using the blood purification device 100C is the same as that described in the first embodiment, so a description thereof will be omitted. As for the blood return process, in addition to that described in the third embodiment, the control device 140 draws blood using a liquid (dialysis fluid, saline) introduced from the substitution fluid bag, which is the substitution fluid supply source 152.

The blood purification apparatus 100C of the fourth embodiment described above provides the following advantages in addition to the above-mentioned advantages (1) and (2).
(8) In the blood purification apparatus 100C in which blood removal and blood return are alternately performed using a single puncture needle SN, the blood return process can also be performed by offline hemofiltration therapy by using a substitution fluid bag as the substitution fluid supply source 152B.

Although the preferred embodiments of the blood purification device of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments and can be modified as appropriate.

For example, in the above embodiment, the system is controlled so that the circulation process is not performed after the blood removal process is completed, and the system is controlled so that the circulation process is not performed after the blood return process is completed, but this is not limited to the above. For example, the system may be controlled so that the circulation process is performed after the blood removal process, or so that the circulation process is performed after the blood return process.

REFERENCE SIGNS LIST 100 Blood purification device 110 Blood circuit 111 Arterial line 111c Blood pump 112 Venous line 120 Blood purifier 130 Dialysis fluid circuit 140 Control device (control unit)
151a Substitution fluid line (replacement fluid line)
152 Replacement fluid supply source, replacement fluid bag (medicinal fluid bag)
1333 Water removal/back-filtration pump (water removal/back-filtration means)
BP Branch Pipe (Branch)
SN Puncture Needle

Claims (11)

A blood purification device that alternately removes and returns blood using a single puncture needle,
The blood circuit,
a blood purifier disposed in the blood circuit;
a blood pump disposed in the blood circuit and supplying blood to the blood purifier;
an arterial line connected to the upstream side of the blood purifier;
a venous line connected to the downstream side of the blood purifier;
a branch portion connected to the puncture needle, the branch portion being connected to an upstream end of the arterial line and a downstream end of the venous line;
a dialysis fluid circuit connected to the blood purifier and supplying a dialysis fluid to the blood purifier;
a water removal/backfiltration means arranged in the dialysis fluid circuit and supplying the dialysis fluid so as to apply a negative or positive pressure to the filtration membrane of the blood purifier;
a control unit that controls the blood circulation system so as to repeatedly perform a treatment process including a blood removal process of introducing blood into the blood circuit and a blood return process of withdrawing blood from the blood circuit;
The control unit sets the amount of blood removed in the blood removal process to be 60% to 70% of the internal volume of the blood purifier and the blood circuit, drives the blood pump in the forward rotation direction in the blood removal process, and controls the water removal/backfiltration means to send dialysis fluid in the water removal direction, and controls the blood pump and the water removal/backfiltration means so that the blood pump's sending speed is faster than the water removal direction sending speed of the water removal/backfiltration means, thereby causing blood to flow again from the venous line to the arterial line at the branching section. The blood purification device according to claim 1, wherein the control unit controls the blood pump and the water removal/backfiltration means so that the patient's blood concentration becomes a target blood concentration during the blood removal process. The blood purification device according to claim 1 or 2, wherein the control unit controls the blood pump and the water removal/backfiltration means to perform the blood return process after the blood removal process without performing a circulation process in which the operation of the water removal/backfiltration means is stopped to circulate blood through the blood circuit. The blood purification device according to claim 3, wherein the control unit drives the blood pump in the forward rotation direction and controls the water removal/backfiltration pump to send dialysis fluid in the backfiltration direction during the blood return process. The blood purification device according to claim 4, wherein the control unit controls the blood pump and the water removal/backfiltration means so that the amount of blood returned to the patient in the blood return process is less than the amount of blood removed from the patient in the blood removal process. The blood purification device according to claim 4, wherein the control unit controls the blood pump and the water removal/backfiltration means to perform the next blood removal step without performing the circulation step of circulating blood through the blood circuit by stopping the operation of the water removal/backfiltration means after the blood return step. The blood purification device according to claim 1 or 2, wherein the control unit withdraws blood using back-filtered dialysis fluid introduced from the blood purifier during the blood return process. The blood circuit includes a fluid replacement line connected to the arterial line,
3. The blood purification apparatus according to claim 1, wherein the control unit withdraws blood by using a dialysate introduced from the fluid replacement line in the blood returning step. the blood circuit includes a fluid replacement line connected to the venous line,
3. The blood purification apparatus according to claim 1, wherein the control unit withdraws blood by using a dialysate introduced from the fluid replacement line in the blood returning step. The blood circuit includes a drug solution bag connected to the arterial line,
3. The blood purification apparatus according to claim 1, wherein the control unit withdraws blood by using a liquid introduced from the drug solution bag in the blood returning step. the blood circuit includes a drug solution bag connected to the venous line;
3. The blood purification apparatus according to claim 1, wherein the control unit withdraws blood by using a liquid introduced from the drug solution bag in the blood returning step.

Images