JP3328078B2 - Diafiltration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diafiltration apparatus for dialysis or filtration of a body fluid such as blood, and more particularly, to pushing a dialysate into a body fluid through a semi-permeable membrane and then extracting water from the body fluid (filtration). TECHNICAL FIELD The present invention relates to a diafiltration apparatus capable of easily and alternately repeating an operation with a compact apparatus.

[0002]

2. Description of the Related Art Conventionally, in a dialysis and purification operation of a body fluid such as blood, it has been repeatedly performed to push a dialysate from a dialysate side to a body fluid side and to draw water from a body fluid side to a dialysate side. By performing, hemofiltration (HF) effect and hemodialysis (HD)
Various diafiltration devices have been proposed which combine the effects with high efficiency and enable easy operation of dialysis, and which do not require a replacement liquid introduction mechanism which is indispensable in a conventional HF operation device. ing.

For example, Japanese Patent Application Laid-Open No. 57-173062 discloses an inexpensive diafiltration apparatus which enables highly efficient dialysis and filtration, is easy to operate, and is inexpensive. That is, FIG. 14 shows the configuration of the diafiltration apparatus. The dialysis device 14 is supplied through the supply passage 13 by the alternate operation of the first pump means 10 and the second pump means 12.
The amount of dialysate supplied to the dialyser or the amount of dialysate discharged from the dialyzer 14 to the discharge passage 15 increases or decreases, thereby increasing the amount of dialysate flowing into the dialyzer 14 and the amount of dialysate from the dialyzer 14. The difference (per unit time) from the outflow can be repeatedly changed from positive to negative and from negative to positive,
Therefore, the configuration is such that the operation of pushing the dialysate into the body fluid through the semipermeable membrane in the dialyzer 14 and extracting water from the body fluid can be repeatedly performed.

According to the diafiltration apparatus thus constructed, the amount of dialysate taken out of the system from the dialysate flow path by the first pump 10 and the dialysate flow path by the second pump 12 Since the amount of liquid pushed from outside the system is equal, the amount of liquid drawn from the body and the amount of liquid pushed into the body are subtracted from the body fluid determined by the inflow and outflow adjustment mechanism 16 to outside the body. Water content. By repeating these two types of operations alternately, conventional HF operations can be performed using the same device.
HD operation can also be performed. Note that FIG.
, Reference numeral 18 indicates a dialysate tank, and 19,
Reference numeral 20 denotes a control device for detecting the dialysate level in the tank 12 and controlling the first pump 10 and the second pump 12, and 21 and 22 further control the pressure in the dialysate discharge passage 15. A control device for detecting and controlling the first pump 10 and the second pump 12 is shown.

Further, Japanese Patent Application Laid-Open No. 61-147681 discloses that the backwashing of a membrane in a dialyzer or a filter can be effectively and efficiently achieved with a relatively simple structure, and that a simple operation can be applied to a living body. There is disclosed an artificial kidney device that can be safely handled. That is, FIG. 15 shows the configuration of this artificial kidney apparatus. A dialyzer (filter) 28 that defines a blood system 24 and a dialysate (filtrate) system 26 through a semipermeable membrane (filtration membrane) is provided. And reservoirs 34 and 36 provided with load cells 30 and 32 are connected to the blood system 24 and the dialysate (filtrate) system 26 via reversible liquid sending means P1 and P2, respectively. The diafiltration and backwashing of the semipermeable membrane are performed by changing the pressure condition in the dialyzer (filter) 28 by switching the means P1 and P2 back and forth.

[0006] According to the artificial kidney apparatus configured as described above, it is possible to achieve the backwashing of the membrane while always keeping the amount of liquid returned to the body through the dialyzer 28 of the blood system 24 constant. Therefore, even if the operation is rapidly switched from the dialysis or filtration operation to the reverse operation, for example, there is no disconnection of the system or impact on the living body, and safe and effective backwashing can be realized.

Furthermore, Japanese Patent Application Laid-Open No. 5-245195 discloses that the conventional diafiltration apparatus greatly changes the blood flow on the vein side when the dialysate is taken in and out of the filtration dialyzer, and therefore, the physical burden on the patient is large. Also, if the blood flow changes significantly, the burden on the shunt will also increase, shortening the life of the shunt, and it is difficult to confirm whether extracorporeal blood circulation is normal because the blood volume is not stable. A hemofiltration and dialysis device with a function to prevent the performance of the membrane from decreasing to reduce the change in the blood flow on the venous side is disclosed. That is, FIG. 16 shows the configuration of this hemodiafiltration apparatus, in which a filtration dialyzer 40, a blood inlet side (arterial side) 41 and an outlet side (venous side) of this filtration dialyzer are shown.
43, blood chambers 42, 44 provided respectively;
An ultrafiltration amount control mechanism 46 for controlling the difference in volume between the fresh dialysate flowing into the filtration dialyzer and the used dialysate flowing out from the filtration dialyzer as a water removal amount;
Between the dialysate outlet 45 and the venous blood chamber 44, a reciprocating pump 48 having a cylinder defined by a buffer air chamber 47a and a dialysate chamber 47b with a piston 47 interposed therebetween. Dialysate outlet 45 of dialyzer 40
And the dialysate chamber 47b of the reciprocating pump 48, and the air chamber 44a of the venous blood chamber 44 and the reciprocating pump 48.
And the buffer air chambers 47a are connected to each other.

[0008] According to the hemodiafiltration apparatus configured as described above, the blood flow on the venous side can be stabilized, so that the burden on the circulatory system of the patient can be reduced and the extracorporeal circulation of blood. It is easy to confirm whether or not the operation is performed normally.

[0009]

However, in the above-mentioned various conventional devices, for example, FIGS.
According to the configuration shown in FIG. 5, power for driving each pump for injecting and withdrawing dialysate from the dialyzer or the like is required. Also, in the configuration shown in FIG. Therefore, power for driving the piston is required, which makes it difficult to reduce the size of each device and makes maintenance work and the like troublesome.

Further, as shown in FIG. 15, in an apparatus requiring a reservoir, there is a problem that the reservoir cannot be sufficiently cleaned and disinfected.

An object of the present invention is to provide a mechanism other than the ultrafiltration amount control mechanism which does not require a driving source, can be simply and compactly formed, has sufficient strength, and is inexpensive. Another object of the present invention is to provide a diafiltration apparatus which can be manufactured easily, and which is easy to maintain and easy to handle.

[0012]

To achieve the above object, a diafiltration apparatus according to the present invention is provided with a dialyzer for defining a body fluid system such as blood and a dialysate system through a semipermeable membrane. In a diafiltration apparatus for performing diafiltration of a body fluid, an ultrafiltration amount control mechanism for controlling a supply amount and a discharge amount of the dialysate to the dialyzer and a means for changing a dialysate flow rate are provided, and By connecting and arranging a buffering means for buffering a change in dialysate flow rate in a part of the dialysate piping system connected to the external filtration amount control mechanism, the pressure change in the dialyzer can be achieved.
It is characterized in that it is configured to increase the movement .

In the above-mentioned diafiltration apparatus, the ultrafiltration amount control mechanism is constituted by a reciprocating pump having a single plunger and two pump units having the same volume and alternately performing suction and discharge operations. It can be configured to also have means for changing the liquid flow rate.

Further, the ultrafiltration amount control mechanism is constituted by a pair of diaphragm chambers, and an auxiliary pump is provided in a part of the dialysate piping system so as to perform a pump operation so that the dialysate flow rate fluctuates. And a buffering means for buffering fluctuations in the dialysate flow rate is connected to the auxiliary pump.

A restrictor, an opening / closing mechanism or a variable restrictor whose flow path area can be adjusted between the buffering means and the dialyzer of the dialysate piping system in which buffering means for buffering fluctuations in dialysate flow rate are connected and arranged. Can be provided.

A pressure adjusting mechanism for adjusting the amount of dialysate stored in the buffering means by the strength of a damper for a dialysate piping system connected with a buffering means for buffering fluctuations in dialysate flow rate. Can also be provided.

Further, by connecting and connecting a buffering means for buffering a change in blood flow to the venous blood system connected to the dialyzer, a change in venous pressure can be effectively suppressed. In this case, a bag may be provided so as to communicate with the venous blood system directly or in the upper part of the venous blood drip chamber, so as to automatically absorb fluctuations in venous pressure. Further, a pressure biasing device for applying pressure from the outside is provided in a bag provided so as to communicate with the venous blood system directly or in the upper part of the venous blood drip chamber, and the fluctuation of the venous pressure is forcibly performed. It can also be configured to absorb.

[0018]

According to the diafiltration apparatus of the present invention, there is provided a diafiltration apparatus for diafiltrating a body fluid by providing a dialyzer for defining a body fluid system such as blood and a dialysate system through a semipermeable membrane. An ultrafiltration control mechanism for controlling the supply and discharge of dialysate to the dialyzer and means for varying the dialysate flow rate, and a communication connection between the dialyzer and the ultrafiltration control mechanism; By connecting and arranging a buffering means such as an accumulator for buffering fluctuations in the dialysate flow rate in a part of the dialysate piping system to be performed, the supply and discharge operations of the dialysate by the ultrafiltration amount control mechanism are symmetric. In addition, a change in the amount of dialysate stored in the buffering means occurs, whereby the infusion and withdrawal of dialysate in contact with body fluid via the semipermeable membrane in the dialyzer can be effectively achieved. In this case, the buffering means can be operated without requiring an external drive source.

[0019]

Next, an embodiment of a diafiltration apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a diafiltration apparatus according to the present invention. Reference numeral 50 denotes a dialyzer. Inside the dialyzer 50, a blood chamber is provided via a semi-permeable membrane. And a dialysate chamber are defined, and in the blood chamber, the arterial blood system 51 and the venous blood system 52
Are connected to each other, and a dialysate supply system 53 and a dialysate discharge system 54 are connected to the inlet and outlet of the dialysate chamber, respectively. However, the dialysate system is provided with an ultrafiltration amount control mechanism and a means for varying the dialysate flow rate, and by these mechanisms and means,
As shown in FIG. 2A, the supply and discharge of the dialysate are performed simultaneously at a constant ratio.

That is, in the embodiment shown in FIG.
As a means for changing the dialysate flow rate, for example, a reciprocating pump 56 having a single plunger and a pump unit having two identical volumes and alternately performing suction and discharge operations is configured,
Ultrafiltration amount control mechanism 58 having this reciprocating pump 56
Is provided. A part of the dialysate discharge system 54 connected between the ultrafiltration amount control mechanism 58 and the dialyzer 50 includes:
For example, a buffering means 60 composed of an accumulator or the like for buffering a change in the dialysate flow rate is connected and arranged.

According to the diafiltration apparatus of this embodiment configured as described above, the ultrafiltration amount control mechanism 58 having the reciprocating pump 56 as means for changing the dialysate flow rate is used.
Since the dialysate supplied to the dialyzer 50 is an intermittent flow as shown in FIG. 2A, the buffering means 60 can spontaneously repeat the volume change due to the pipe resistance of the dialysate system. That is, in the first half cycle, when the dialysate is supplied to the dialysate supply system 53 by the operation of the reciprocating pump 56, the dialysate is stored in the buffering means 60 in the other pump. Since the dialysate is sucked from the dialysate discharge system 54, the dialysate in the dialysate supply system 53 including the dialyzer 50 is in a stagnant state, and the dialysate volume in the dialysate supply system 53 temporarily becomes excessive. As a result, the dialysate is infused into the blood through the semi-permeable membrane. And in the next half cycle, the buffering means 60
The excess dialysate in the inside is drawn out to recover the original state, and at this time, the water on the blood side is drawn out to the dialysate side through the semipermeable membrane.

Therefore, when the volume of the buffering means 60 increases, it means that the same amount of water as the increased amount has been filtered from the blood in the dialyzer 50. on the other hand,
When the volume of the buffering means 60 is reduced, it means that the dialysate in the dialyzer 50 is infused into the blood side in the same amount as the reduced amount. That is, as shown in FIG. 2B, the fluctuation range of the discharge flow rate of the dialysate from the dialyzer 50 is reduced, and the dialysate is withdrawn and injected by the difference from the dialysate supply flow rate. become.

Further, by providing the throttle 62 upstream of the buffering means 60,
Can be made larger, and the amount of water and dialysate drawn out / injected into the dialyzer 50 can be increased.

FIG. 3 shows another embodiment of the diafiltration apparatus according to the present invention. That is, in the present embodiment, the buffering means 60 is connected and arranged to the dialysate supply system 53, and the throttle 6 is provided downstream of the buffering means 60.
2 is arranged. With this configuration, the buffering means 60 can be operated in the same manner as in the embodiment. In this case, in this embodiment, as shown in FIG. 4, the fluctuation range of the supply flow rate of the dialysate is reduced, and the dialysate is withdrawn and injected.

In the present invention, as described above, the buffering means 60 for buffering fluctuations in the flow rate of the dialysate is not limited to an accumulator. For example, as shown in FIG. By providing the liquid storage tank 70 and connecting it to the dialysis fluid piping system, a configuration in which the air layer 70a performs a damper function to buffer the dialysis fluid can be applied.

As an alternative, as shown in FIG. 6, a spring 74 is mounted on a volume-changeable means composed of a plunger mechanism 72, and a stopper 76 is provided on the plunger mechanism 72 so that the position can be adjusted appropriately. , The buffering means 60 can also be configured. In this case, the spring 74 exerts a damper function to buffer the dialysate. In this case, the buffering tolerance can be adjusted by changing the elasticity of the spring 74 and adjusting the position of the stopper 76.

Further, as shown in FIG. 7, a spring 74 is attached to a variable volume means comprising a diaphragm mechanism 78 in the same manner as described above, and a buffering means 6 is provided.
0 can also be configured. In addition, a bellows mechanism or the like can be applied instead of the diaphragm mechanism 78.

Further, as the buffering means 60, a flexible elastic bag such as a rubber balloon can be used. That is, the buffering means 60
It is preferable that the dialysate has a function of drawing out and temporarily storing the dialysate without using external power from the dialyzer 50.

FIG. 8 shows still another embodiment of the diafiltration apparatus according to the present invention. That is, this embodiment is different from the embodiment shown in FIG. 1 in that an opening / closing mechanism 80 such as a solenoid valve is arranged in place of the throttle 62 provided in the dialysate piping system together with the buffering means 60. In this case, the amount of dialysate withdrawn / injected can be further increased as compared with the embodiment shown in FIG.

FIG. 9 shows a modification of the embodiment shown in FIG. That is, in this embodiment, a variable throttle 82 whose flow path area is adjustable is arranged instead of the throttle. In this case, according to this embodiment, by adjusting the variable throttle 82 via the control unit 84, it is possible to adjust the amount of dialysate withdrawn / injected.

FIG. 10 shows still another modification of the embodiment shown in FIG. That is, in the present embodiment, the throttle is omitted, and the pressure adjusting mechanism 86 that can adjust the external gas pressure is provided in the accumulator as the buffering means 60. In this case, according to the present embodiment, by adjusting the pressure adjusting mechanism 86 via the control unit 88, it is possible to adjust the amount of dialysate withdrawn / injected.

As shown in FIG. 11, a pair of diaphragm chambers 90a and 90 are used as means for changing the dialysate flow rate.
The ultrafiltration amount control mechanism 58 using b may be configured. As described above, according to the ultrafiltration amount control mechanism 58 using the diaphragm chamber, since the dialysate supplied to the dialyzer 50 is a steady flow, spontaneous volume change of the buffering means 60 cannot be expected. . So, in this case,
An auxiliary pump 92 for moving the dialysate is disposed in the dialysate system (dialysate discharge system 54 in the illustrated embodiment), and the auxiliary pump 92 and the buffering means 60 are provided. Therefore, by controlling the speed of the auxiliary pump 92, the volume of the buffering means 60 can be changed in the same manner as described above.

In the application of the diafiltration apparatus according to the present invention, when dialysate is infused / withdrawn in the dialyzer 50, the flow rate of blood returned to the patient repeatedly increases and decreases. Vein pressure fluctuates. Therefore, if the fluctuation of the venous pressure is suppressed, the physical burden on the patient will be further reduced. Therefore, for example, in the step of injecting the dialysate, the filling amount in the blood tube is increased, and in the withdrawal step, the filling amount in the blood tube is reduced so that the blood return flow rate is averaged. preferable. In other words, the fluctuation of the venous pressure can be suppressed by arranging the buffering means for buffering the fluctuation of the blood flow to the venous blood system 52 connected to the dialyzer 50.

FIG. 12 shows a configuration in which the fluctuation of the venous pressure is suppressed without external power, and one of the buffering means provided in the venous blood system 52 of the diafiltration apparatus according to the present invention. It shows an embodiment. That is, in this embodiment, in the venous blood system 52 of the embodiment shown in FIG. 1, a soft bag 96 is connected so as to communicate directly with the venous blood system 52 or to the upper part of the venous blood drip chamber 94. It is arranged. It is preferable that the bag 96 be made of a resilient material. With this configuration, when the return blood flow increases and the venous pressure increases, the volume of the bag 96 increases, and the effect of reducing the return blood flow acts to prevent the venous pressure from becoming excessive. be able to. Further, when the blood return flow rate decreases and the venous pressure decreases during the withdrawal step, the volume of the bag 96 decreases, and the effect of increasing the blood return flow rate acts, thereby preventing the venous pressure from becoming too small. be able to.

FIG. 13 shows a modification of the buffering means configured to suppress the fluctuation of the venous pressure by using an external power. That is, in the present embodiment, a pressure is externally applied to the bag 96 provided in the embodiment shown in FIG. 12 by an appropriate pressure urging device 98 to forcibly form the blood constituting the venous blood system 52. By changing the amount of blood filling in the tube, it is possible to prevent the venous pressure from becoming too high and to prevent the venous pressure from becoming too low, as in the above embodiment.

As an alternative, the volume of the air layer in the venous blood drip chamber 94 shown in FIG. 12 may be increased, or a hard elastic bag may be attached to the upper part of the drip chamber 94 to increase the amount of air. Thus, it is possible to prevent the venous pressure from becoming too large or too small due to the damper effect of the air. In other words, in this case, when the venous pressure rises, the surrounding air is compressed, the blood volume in the blood circuit increases, and the effect of reducing the blood return flow rate works, preventing the venous pressure from becoming excessive. I do. In addition, when the venous pressure decreases, the surrounding air expands and the amount of blood filling in the blood circuit decreases, which acts to increase the blood return flow rate, thereby preventing the venous pressure from becoming too small. .

Although the preferred embodiments of the present invention have been described above, the present invention not only allows these embodiments to be used in combination with each other but also various other embodiments within the spirit and scope of the present invention. It is needless to say that the design can be changed.

[0039]

As is apparent from the above-described embodiments, according to the present invention, a dialysis device is provided for defining a body fluid system such as blood and a dialysate system through a semipermeable membrane, and diafiltration of the body fluid is performed. A diafiltration apparatus, comprising: an ultrafiltration amount control mechanism for controlling a supply amount and a discharge amount of dialysate to the dialyzer; and means for varying a dialysate flow rate, wherein the dialyzer and the ultrafiltration amount control mechanism are provided. Part of the dialysate piping system connected to
With the configuration in which the buffering means for buffering the fluctuation of the dialysate flow rate is connected and arranged, the volume change of the buffering means is caused symmetrically with the supply and discharge operation of the dialysate by the ultrafiltration amount control mechanism. Thus, the infusion and withdrawal of the dialysate in contact with the body fluid via the semipermeable membrane in the dialyzer can be effectively achieved.

In particular, in the present invention, the buffering means can be operated without requiring an external drive source, so that the structure is simplified and
It has the advantages of excellent durability and easy maintenance work.
Further, the size of the apparatus can be reduced, so that not only the manufacturing cost can be reduced, but also the operation cost can be maintained in the same manner as a normal dialysis apparatus. Furthermore, since the buffering means can have a very simple configuration, cleaning and disinfection operations can be performed easily and sufficiently.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram showing one embodiment of a diafiltration apparatus according to the present invention.

FIGS. 2A and 2B show the dialysate sending and discharging characteristics of the diafiltration apparatus according to the present invention, wherein FIG. 2A is a waveform diagram showing basic dialysate sending and discharging characteristics, and FIG. FIG. 3 is a waveform diagram showing the sending and discharging characteristics of the dialysate in the embodiment shown in FIG.

FIG. 3 is a schematic system diagram showing another embodiment of the diafiltration apparatus according to the present invention.

FIG. 4 is a waveform diagram showing the sending and discharging characteristics of the dialysate in the embodiment shown in FIG.

FIG. 5 is a schematic system diagram showing a modification of the buffering means of the diafiltration device shown in FIG.

FIG. 6 is a schematic system diagram showing another modified example of the buffering means of the diafiltration device shown in FIG.

FIG. 7 is a schematic system diagram showing still another modified example of the buffering means of the diafiltration device shown in FIG. 1;

FIG. 8 is a schematic system diagram showing a modified example of the diaphragm of the diafiltration device shown in FIG.

FIG. 9 is a schematic system diagram showing another modified example of the throttle of the diafiltration device shown in FIG. 1;

FIG. 10 is a schematic system diagram showing still another modified example of the buffering means of the diafiltration device shown in FIG. 1;

FIG. 11 is a schematic system diagram showing still another embodiment of the diafiltration apparatus according to the present invention.

FIG. 12 is a schematic system diagram showing still another embodiment of the diafiltration apparatus according to the present invention.

FIG. 13 is a schematic system diagram showing a modified example of the diafiltration device shown in FIG.

FIG. 14 is a system diagram showing a configuration of a conventional diafiltration device.

FIG. 15 is a system diagram showing a configuration of a conventional artificial kidney apparatus for performing diafiltration.

FIG. 16 is a system diagram showing a configuration of a conventional hemofiltration / dialysis apparatus for performing diafiltration.

[Explanation of symbols]

 Reference Signs List 50 dialyzer 51 arterial blood system 52 venous blood system 53 dialysate supply system 54 dialysate discharge system 56 reciprocating pump 58 ultrafiltration amount control mechanism 60 buffering means 62 throttle 70 dialysate storage tank 70a air layer 72 plunger Mechanism 74 Spring 76 Stopper 78 Diaphragm mechanism 80 Opening / closing mechanism 82 Variable throttle 84 Control unit 86 Pressure adjusting mechanism 88 Control unit 90a, 90b Diaphragm chamber 92 Auxiliary pump 94 Intravenous blood drip chamber 96 Bag 98 Pressure biasing device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-336074 (JP, A) JP-A-5-146506 (JP, A) JP-A-55-148564 (JP, A) JP-A-61-1986 25565 (JP, A) JP-A-61-143068 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61M 1/14-1/36

Claims (10)

(57) [Claims] 1. A diafiltration apparatus for providing diafiltration of a body fluid by providing a dialyzer for defining a body fluid system such as blood and a dialysate system via a semipermeable membrane, wherein a supply amount of the dialysate to the dialyzer A part of the dialysate piping system, which is provided with an ultrafiltration amount control mechanism for controlling the amount of dialysis fluid and a means for varying the dialysate flow rate, and is connected between the dialyzer and the ultrafiltration amount control mechanism. Toru by connecting arrangement buffering means for buffering the variation in dialysate flow rate
A diafiltration apparatus characterized in that the pressure fluctuation in the analyzer is increased . 2. The ultrafiltration amount control mechanism is constituted by a reciprocating pump having a single plunger and two pump units having the same volume and alternately performing suction and discharge operations, and varies the dialysate flow rate. 2. The diafiltration apparatus according to claim 1, wherein the diafiltration apparatus is configured to have a means. 3. The ultrafiltration amount control mechanism is constituted by a pair of diaphragm chambers, and an auxiliary pump is provided in a part of the dialysate piping system to perform a pump operation so that the dialysate flow rate fluctuates. 2. The diafiltration apparatus according to claim 1, wherein a buffering means for buffering a change in dialysate flow rate is connected to the auxiliary pump. 4. The dialyser according to claim 1, wherein a throttle is provided between the buffering means and the dialyzer of the dialysate piping system, wherein the buffering means for buffering fluctuations in the dialysate flow rate is connected.
4. The diafiltration apparatus according to any one of claims 1 to 3. 5. The dialyzer according to claim 1, further comprising an opening / closing mechanism provided between said buffering means and said dialyzer of said dialysate piping system, said buffering means being connected to buffering means for buffering fluctuations in dialysate flow rate. A diafiltration apparatus according to any one of the above. 6. A variable throttle having a flow path area adjustable between said buffering means and a dialyzer of a dialysate piping system to which buffering means for buffering fluctuations in dialysate flow rate is connected and arranged. The diafiltration apparatus according to any one of claims 1 to 3, wherein 7. A pressure adjusting mechanism for adjusting the amount of dialysate stored in said buffering means by the strength of a damper for a dialysate piping system connected and arranged with buffering means for buffering fluctuations in dialysate flow rate. The diafiltration device according to any one of claims 1 to 3, further comprising: 8. The diafiltration apparatus according to claim 1, wherein a buffering means for buffering a change in blood flow is connected to the venous blood system connected to the dialyzer. 9. A buffering means for buffering fluctuations in blood flow is provided with a bag so as to communicate directly with the venous blood system or in the upper part of the venous blood drip chamber, and automatically controls fluctuations in venous pressure. 9. The diafiltration device according to claim 8, wherein the device is configured to absorb. 10. A bag provided so as to communicate directly with the venous blood system or in the upper part of the venous blood drip chamber is provided with a pressure biasing device for applying pressure from the outside, thereby forcing venous pressure fluctuations. 10. The diafiltration device according to claim 9, wherein the diafiltration device is configured to absorb the gas.