JP2003265602A - Blood circuit - Google Patents

Abstract

(57) [Problem] To provide a blood circuit capable of avoiding blood stagnation during dialysis treatment and connecting the tip of the arterial blood circuit to the venous blood circuit during blood return. A dialyzer (2) having a hollow fiber membrane (3) therein and a blood flow path (2a) through which blood flows through the hollow fiber membrane (3) and a dialysate flow path (2b) through which dialysate flows is formed. A blood circuit 1 to be connected, the tip of which is formed so that the arterial puncture needle a can be attached, and the blood pump 5 can be attached in the middle, and the tip of the arterial blood circuit 1a is connected to the venous puncture needle b. A venous blood circuit 1 formed so as to be attachable and connected to a drip chamber 7 in the middle
b and the arterial blood circuit 1a formed on the air layer side of the drip chamber 7 of the venous blood circuit 1b when returning blood.
The connecting means 16 capable of connecting the tip of the auxiliary tube 15 is provided at the tip of the auxiliary tube 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blood circuit after blood purification and a blood circuit for returning blood remaining in a blood purifier into the body of a patient.

[0002]

2. Description of the Related Art In general, a blood circuit has an arterial blood circuit having an arterial puncture needle attached to its tip for collecting blood from a patient, and a vein side having an venous puncture needle attached to its tip for returning blood to the patient. It is mainly composed of a blood circuit, and the base ends of the arterial blood circuit and the venous blood circuit are connected to a blood purifier such as a dialyzer for use.

In such a blood purifier, a blood purification membrane for purifying blood is internally provided, and a blood flow passage through which blood flows and a dialysate passage through which dialysate flows are formed through the blood purification membrane, The proximal end of the arterial blood circuit is connected to the blood introduction port of the blood flow path, and the proximal end of the vein side blood circuit is connected to the blood discharge port of the blood flow path.

A dialyzer body for supplying dialysate to the blood purifier and discharging the dialysate after blood purification at the dialysate inlet and the dialysate outlet in the dialysate flow path of the blood purifier. The dialysate introduction line and the dialysate discharge line are connected to each other. The dialyzer body is provided with various components such as a dialysate supply source for supplying dialysate to the dialysate introduction line and a water removal pump.

A flexible tube made of a soft resin for attaching an ironing type blood pump is connected to the arterial blood circuit on the way, and air bubbles in the blood are connected to the venous circuit on the way. Is connected to the drip chamber. As a result, the blood collected from the arterial puncture needle by the operation of the blood pump reaches the blood purifier, is brought into contact with the dialysate through the blood purifying membrane, and waste products are flushed to the dialysate side and purified. The subsequent blood is defoamed in the drip chamber, passes through the venous blood circuit, is returned from the venous puncture needle into the patient's body, and a series of dialysis treatments are performed.

After completion of such dialysis treatment, blood remains in the blood flow path of the blood circuit and the blood purifier, and therefore it is necessary to return the blood to the patient (such work). Hereinafter referred to as "return blood"). As a conventional method for returning blood, for example, Japanese Patent Laid-Open No. 2001-252352
The one disclosed in the publication is cited.

[0007] In the publication, a connecting member for connecting the tip of the arterial blood circuit is provided between the blood purifier and the drip chamber in the venous blood circuit, and when returning blood after completion of dialysis treatment, the artery side is connected. A technique for connecting the tip of a blood circuit to a connecting member is disclosed. Then, the dialysate is pressure-fed to the blood purifier while driving the blood pump, and the dialysate is flowed through the blood purification membrane to the blood flow path side to replace the blood in the blood circuit and the blood purifier with the dialysate. Then blood was being returned.

[0008]

However, in the above-mentioned conventional blood circuit, a connecting member for connecting the tip of the arterial blood circuit is provided between the blood purifier and the drip chamber in the venous blood circuit. Since it has been
There were the following problems. That is, the connecting member is in a state of being connected to the blood circuit through which blood flows even during normal dialysis, and a step is formed at the joint between the inner peripheral surface of the connecting member and the inner peripheral surface of the blood circuit. Then, there is a possibility that the flow of the blood may be obstructed by the step and the blood may stay.

When the blood is retained in such a stepped portion, the blood may be coagulated to cause a thrombus, which causes a problem. In addition, normally, before using the blood circuit, a priming work is performed in which physiological saline or the like is caused to flow in the blood circuit and the blood purifier to clean the blood circuit.
At the time of this priming, bubbles may remain in the step portion, which may adversely affect the subsequent dialysis treatment.

The present invention has been made in view of such circumstances, and it is possible to avoid the retention of blood during dialysis treatment, and at the time of returning blood, the tip of the arterial blood circuit is changed to the venous blood circuit. It is to provide a blood circuit that can be connected.

[0011]

The invention according to claim 1 is
A blood circuit that has a blood purification membrane for purifying blood and is connected to the blood passage of a blood purifier in which the blood passage of the patient's blood is formed, and the tip can attach a puncture needle The base end is connectable to the blood inlet in the blood flow path of the blood purifier, and the arterial blood circuit to which a blood pump can be attached in the middle and the tip to which a puncture needle can be attached A venous blood circuit having a proximal end connectable to a blood outlet in the blood flow path of the blood purifier, and a drip chamber connected in the middle, and a drip chamber of the venous blood circuit. A connecting portion formed on the air layer side and capable of connecting the tip of the arterial blood circuit when returning blood.

According to a second aspect of the present invention, the connecting portion is provided at an auxiliary line extending from the air layer side of the drip chamber and at the tip of the auxiliary line, and at the tip of the arterial blood circuit. And a connecting means connectable to the arterial shunt connector.

According to a third aspect of the present invention, the connecting portion is a female connector which is connectable by fluid-tightly fitting and locking the tip of the artery-side shunt connector provided at the tip of the artery-side blood circuit. It is characterized by

According to a fourth aspect of the present invention, a lock ring having a screw shape is attached to the distal end side of the arterial blood circuit, and the connecting means can be engaged with the screw shape of the lock ring by screwing. It is characterized by

According to a fifth aspect of the present invention, the connecting portion is a rubber button provided on the air layer side of the drip chamber and connectable by puncturing the artery side puncture needle when returning blood. And

According to a sixth aspect of the present invention, the blood purifier comprises a dialyzer in which a dialysate flow path adjacent to the blood flow path is formed via the blood purification membrane, and a dialysate flow in the dialyzer. A dialyzer is connected to the dialysate inlet and the dialysate outlet of the passage.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. As shown in FIG. 1, the blood circuit according to the present embodiment has an arterial blood circuit 1a.
And a venous blood circuit 1b, and the proximal ends of the arterial blood circuit 1a and the venous blood circuit 1b are connected to the blood inlet 2c and the blood outlet 2d of the dialyzer 2 (blood purifier), respectively. Is configured to get.

As shown in FIG. 2, the dialyzer 2 has a blood inlet 2c and a blood outlet 2d formed on both sides of a substantially cylindrical casing, and a dialysate inlet 2 on the upper surface.
e and the dialysate outlet 2f are formed. A plurality of hollow fiber membranes 3 (blood purification membranes) are arranged in the housing, and the inside of the hollow fiber membranes 3 communicates the blood inlet port 2c and the blood outlet port 2d with the blood flowing in the blood circuit 1 While forming a blood channel 2a that can flow, the space between the outer peripheral surface of the hollow fiber membrane 3 and the housing is a dialysate inlet 2e and a dialysate outlet 2f.
To form a dialysate flow path 2b which allows the dialysate supplied from the dialyzer body 4 to flow therethrough.

Further, since the hollow fiber membrane 3 is formed with a plurality of micropores, when the blood passes through the blood channel 2a and the dialysate passes through the dialysate channel 2b, the hollow fiber membrane 3 is removed. Through this, unnecessary substances (waste products) in the blood can be dialyzed and removed to the dialysate side. In addition, reference numeral 2g in FIG.
A sealant for fluidly connecting the hollow fiber membrane 3 to the blood inlet 2c is shown, and the sealant 2g is also provided on the blood outlet 2d side.

As shown in FIG. 3, an arterial shunt connector 8 to which an arterial puncture needle a can be connected is provided at the tip of the arterial blood circuit 1a, and a screw shape 9a is provided on the inner peripheral surface. A lock ring 9 is attached to the tip side of the arterial blood circuit 1a. The arterial puncture needle a is shown in FIG.
As shown in FIG. 3, the flange 10a is attached to the projecting end of the mounting body 10 having a substantially conical shape, and the base end of the mounting body 10 is formed with a flange 10a that can be screwed into the screw shape 9a of the lock ring 9.

An arterial puncture needle a is attached to the tip of the arterial blood circuit 1a.
In order to attach, the arterial shunt connector 8 is inserted through the bottom opening of the attachment body 10 and fitted, and after the lock ring 9 is moved to the distal end side, as shown in FIG. 9a is screwed and locked.
At the tip of the vein side blood circuit 1b, the vein side shunt connector 11, the attachment body 13 to which the vein side puncture needle b is attached, and the lock ring 12 are also arranged.

A soft resin flexible tube 6 to which an ironing type blood pump 5 is attached is connected in the middle of the arterial blood circuit 1a. That is, blood pump 5
Rotates the flexible tube 6 while squeezing the flexible tube 6 to cause the blood collected from the arterial puncture needle a to flow in the blood circuit 1 and the dialyzer 2 and return from the venous puncture needle b into the patient's body. It has an effect.

The dialyzer body 4 has a dialysate introduction line 4a connected to the dialysate inlet 2e of the dialyzer 2 and a dialysate discharge line 4b connected to the dialysate outlet 2f, which is not shown. Dialysate introduction line 4a by pump
The dialysate is supplied to the dialysate flow path 2b in the dialyzer 2 via the dialyzer 2 so that the dialysate passing through the dialysate flow path 2b is discharged from the dialysate discharge port 2f to the dialysate discharge line 4b. It is configured.

A bypass line for bypassing a part of the dialysate discharge line 4b is formed in the dialyzer main body 4, and a water removal pump is arranged in the bypass line to remove a desired amount of water. Is configured to be able to. The pump in the dialyzer body 4 and the blood pump 5 are controlled to be synchronized with each other except when the water is removed by the water removing pump.

The above-mentioned vein side shunt connector 11 is provided at the tip of the vein side blood circuit 1b, the vein side puncture needle b is attached through the attachment body 13, and a drip for defoaming in the middle thereof. The chamber 7 is connected. The drip chamber 7 is made of a transparent resin chamber having a storage space 7c capable of storing a predetermined volume (about 10 ml) of liquid (blood) therein, and blood flowing from the dialyzer 2 side as shown in FIG. 7a for introducing the liquid into the accommodation space 7c, and the accommodation space 7c
An outlet 7b is formed to allow the blood inside to flow to the side of the venous puncture needle b.

Of these, the inlet 7a is formed on the upper side of the drip chamber 7, and the outlet 7b is formed on the bottom surface of the drip chamber 7, so that an air layer 7d can be formed on the upper portion in the accommodation space 7c. It is configured. Reference numeral 14 in the figure denotes a mesh covering the outlet port 7b side, and the mesh 14 is configured to remove impurities in the blood led out from the drip chamber 7. Further, the drip chamber referred to in the present invention includes an air layer and a liquid layer, and includes all those having a mesh for blood filtration on the liquid layer side.

Here, an auxiliary line 15 extending from the upper end of the drip chamber 7 in this embodiment to the air layer 7d of the accommodation space 7c is provided. This auxiliary line 1
5 is made of a resin material having substantially the same quality as that of the flexible tube forming the blood circuit 1, and a connecting means 16 for connecting the end of the arterial blood circuit 1a is formed at the end. The connecting means 16 and the auxiliary line 15 are provided in the drip chamber 7
A connecting portion formed on the side of the air layer.

The connecting means 16 is, as shown in FIG.
A flange 16b is provided on the tip side of the tubular body 16a with both ends open.
Is made of a molded hard resin, and the arterial shunt connector 8 (with the attaching body 10 and the arterial puncture needle a removed) is inserted and fitted into the opening on the distal end side when returning blood. It is configured to be connectable. After that, the lock ring 9 arranged at the tip of the arterial blood circuit 1a is moved to the tubular body 16a side, and as shown in FIG.
By screwing a screw shape 9a on the flange 16b of No. 6, the tip of the arterial blood circuit 1a can be locked to the connecting means 16.

Next, the operation of the blood circuit will be described. In FIG. 1, during normal dialysis treatment, the patient is punctured with the artery-side puncture needle a and the vein-side puncture needle b, and the blood pump 5 and the pump in the dialysis machine body 4 are driven. As a result, the blood of the patient collected from the venous puncture needle a passes through the arterial blood circuit 1a to reach the blood flow path 2a from the blood inlet 2c of the dialyzer 2, while the dialysate flows through the dialysate inlet line 4a. Through the dialysate inlet 2e to the dialysate flow path 2b.

When the blood in the blood channel 2a and the dialysate in the dialysate channel 2b come into contact with each other through the hollow fiber membrane 3, waste products of blood are transferred to the dialysate side and purified. .
The purified blood is led from the blood outlet 2d to the vein side blood circuit 1b and returned to the patient's body via the drip chamber 7 and the vein side puncture needle b. In addition, the dialysate mixed with waste products is fed from the dialysate outlet 2f to the dialysate discharge line 4
It is discharged to b. In such a series of dialysis treatments, nothing is connected to the connecting means 16 at the tip of the auxiliary line 15 and no blood flow path is formed.

After the dialysis treatment as described above is completed, in order to return blood, as shown in FIG. 9, with the venous puncture needle b punctured in the patient, the arterial side of the tip of the arterial blood circuit 1a is fed. The puncture needle a is removed and the arterial shunt connector 8 is connected to the connecting means 16. As described above, this connection is made by fitting the artery-side shunt connector 8 into the opening of the tubular body 16a, and then screwing and locking the lock ring 9 to the flange 16b.

After the above connection is completed, the dialysate is sent from the dialyzer body 4 to the dialyzer 2 so that the fluid pressure in the dialysate flow passage 2b becomes higher than that in the blood flow passage 2a. The blood pump 5 is driven as shown in FIG. Then, the dialysate in the dialysate channel 2b passes through the hollow fiber membrane 3 and flows into the blood channel 2a, and is led out from both the blood inlet 2c and the blood outlet 2d. In the process of deriving the dialysate, the residual blood in the blood channel 2a of the dialyzer 2 is pushed out and replaced with the dialysate.

The dialysate delivered to the venous blood circuit 1b reaches the venous puncture needle b through the drip chamber 7 while pushing out residual blood, while the dialysate delivered to the arterial blood circuit 1a is The pump 5 feeds the drip chamber 7 through the artery-side shunt connector 8 and the connecting means 16. That is, both the dialysate drawn out to the arterial blood circuit 1a and the dialysate drawn to the venous blood circuit 1b are introduced into the drip chamber 7 and reach the vein puncture needle b from there.

By such a flow of dialysate, the residual blood in the blood circuit 1 is replaced with dialysate, and the extruded blood is returned to the patient's body via the venous puncture needle b. Here, blood or dialysate flows into the drip chamber 7 from both the inlet 7a on the side surface and the auxiliary line 15 on the upper surface, so that there are a plurality of inflow directions (two directions).
Therefore, the retention of blood or dialysate in the drip chamber 7 can be suppressed, and the blood returning efficiency can be improved.

According to the above-described embodiment, since the tip of the arterial blood circuit 1a is connected to the air layer 7d side of the drip chamber 7, there is no need to provide a separate connecting means in the blood circuit through which blood flows. It is possible to avoid blood retention during dialysis treatment. That is, during normal dialysis treatment, the auxiliary line 15 and the connecting means 16 are provided.
Does not form a main line through which blood flows, so that there is no step in the main line and blood can be prevented from staying.

It should be noted that since a line through which the physiological saline flows does not form during priming, a step is not formed in the line and bubbles and the like remain, which avoids adverse effects on the subsequent dialysis treatment. You can Further, during blood return, filtration is performed by the mesh 14 in the same direction as during dialysis, so that impurities and the like adhering to the mesh 14 during dialysis can be prevented from flowing into the patient's body during blood return. Since the artery-side shunt connector 8 is closed at the time of blood return, when the blood circuit 1 is discarded, the venous-side shunt connector 11 is simply closed to prevent liquid leakage and improve the workability of discarding. it can.

Further, the overflow line and the level adjusting line conventionally formed on the upper portion of the drip chamber can be used as an auxiliary line, and the manufacturing cost can be suppressed. Further, since the connecting means 16 is provided at the tip of the auxiliary line 15, the direction of the connecting means 16 can be adjusted more easily than in the case where the connecting means is fixed to the drip chamber, and the arterial blood circuit 1a. The tip can be easily connected.

Although the present embodiment has been described above, the present invention is not limited to this, and for example, if the attachment of the auxiliary line 15 to the drip chamber 7 becomes the air layer 7d of the drip chamber 7, another position (for example, It may be the upper side surface of the drip chamber 7). That is, if the connecting means is provided on the side of the air layer 7d of the drip chamber 7, the main line through which blood flows is not formed, and the above effect is obtained.

In the above embodiment, the connecting portion is composed of the auxiliary line 15 and the connecting means 16,
For example, as shown in FIG. 10, an opening 7e having a diameter that allows the artery-side shunt connector 8 to be inserted and fitted into the upper surface of the drip chamber 7 may be used as the connection portion. Further, as shown in FIG. 11, a rubber button 7f capable of puncturing the artery side puncture needle a may be provided on the upper surface of the drip chamber 7 and used as a connecting portion.

As shown in the figure, the rubber button 7f is constructed by inserting a material 7fa, such as soft resin or rubber, which can be pierced by a puncture needle into a through hole communicating with the air layer 7d and closing the through hole. The side surface of the material 7fa is covered with a hard resin or the like. Such a rubber button 7
If the connecting portion is composed of f, without removing the arterial puncture needle a,
Directly connect the tip of the arterial blood circuit 1a to the drip chamber 7
Can be connected to.

Furthermore, in the present embodiment, although it should be applied at the time of dialysis treatment, it can be applied to other treatments for blood purification. That is, a blood circuit for continuously separating blood from a patient and continuously returning the blood to the patient, such as plasma separation or a cardiopulmonary circuit, can be applied to blood circuits for purposes other than dialysis.
When used in a cardiopulmonary circuit, a blood reservoir is provided instead of the drip chamber, but the drip chamber according to the present invention also includes such a blood reservoir.

Further, in the present embodiment, the double needle having the artery side puncture needle at the tip of the arterial blood circuit and the vein side puncture needle at the tip of the vein side blood circuit is used. It is also possible to use a single needle in which the tip of the arterial blood circuit and the tip of the venous blood circuit are connected to one puncture needle via a branch tube. When the single needle is used, when the treatment is completed and the arterial shunt connector 8 is detached from the single needle connection part, in order to prevent blood leakage, a blood loss prevention measure is provided by a clamp means attached to the single needle or a coffer (forceps). is necessary.

In this embodiment, the arterial shunt connector 8 attached to each tip of the arterial blood circuit.
Is a luer connector (with an outside diameter dimension and taper angle of a specified standard), but if it can be connected to the connection part formed on the air layer side of the drip chamber, it may be out of specification Good.

[0044]

According to the invention of claim 1, since the tip of the arterial blood circuit is connected to the air layer side of the drip chamber, it is possible to provide a separate connecting means in the blood circuit through which blood flows. In addition, it is possible to avoid stagnation of blood during blood purification and connect the tip of the arterial blood circuit to the venous blood circuit when returning blood.

According to the second aspect of the present invention, since the connecting portion is formed by providing the connecting means at the tip of the auxiliary line extending from the air layer side of the drip chamber, it has been conventionally formed in the upper portion of the drip chamber. The overflow line and the level adjustment line can be used as auxiliary lines, and the manufacturing cost can be suppressed. In addition, since the connecting means is provided at the tip of the auxiliary line, the direction of the connecting means can be adjusted more easily than in the case where the connecting means is fixed to the drip chamber, and the tip of the arterial blood circuit can be easily adjusted. Can be connected.

According to the third aspect of the invention, since the connecting portion is a female connector capable of fitting and locking the tip of the shunt connector on the artery side, the tip of the blood circuit on the arterial side can be drip-connected to the blood circuit on the venous side with a simple structure. It can be connected to a chamber.

According to the fourth aspect of the invention, the connecting means locks the lock ring, which has been conventionally attached to the distal end of the blood circuit, by screwing, so that an increase in manufacturing cost can be suppressed, and more reliable. The arterial blood circuit tip can be connected to the drip chamber.

According to the invention of claim 5, since the connecting portion is constituted by the rubber button provided on the air layer side of the drip chamber, the constitution is simple and the arterial side puncture needle is still attached. In this state, the arterial blood circuit tip can be connected to the drip chamber.

According to the sixth aspect of the present invention, the blood purifier is a dialyzer connected to the dialyzer, and returns the blood of the patient remaining in the blood circuit and the dialyzer after the dialysis treatment. The effect of the invention can be made more effective. That is, dialysis treatment is generally more frequent than other blood purification treatments (for example, about a few times a week), and there is a demand to return more residual blood to the patient in order to avoid anemia. The effect of the present invention, in which more blood can be returned to the patient's body by blood return while avoiding blood retention during dialysis, becomes extremely important.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a state in which normal dialysis treatment is performed in a blood circuit according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a dialyzer (blood purifier) in the blood circuit according to the embodiment of the present invention.

FIG. 3 is a side view showing an arterial shunt connector and a lock ring formed at the tip of the arterial blood circuit in the blood circuit according to the embodiment of the present invention.

FIG. 4 is a side view showing a state in which an arterial puncture needle a is attached to an arterial shunt connector formed at the tip of the arterial blood circuit in the blood circuit according to the embodiment of the present invention.

FIG. 5 is a side view showing a state in which the arterial shunt connector formed at the tip of the arterial blood circuit in the blood circuit according to the embodiment of the present invention is locked by the lock ring 9.

FIG. 6 is a side view showing a drip chamber and a connecting portion (auxiliary line and connecting means) arranged in the venous blood circuit in the blood circuit according to the embodiment of the present invention.

FIG. 7 is a side view showing a state in which an arterial shunt connector at the tip of the arterial blood circuit is connected to the connecting means in the blood circuit according to the embodiment of the present invention.

FIG. 8 is a side view showing a state in which the arterial shunt connector at the tip of the arterial blood circuit is connected to the connecting means in the blood circuit according to the embodiment of the present invention and locked by the lock ring.

FIG. 9 is a schematic diagram showing a state in which blood is returned in the blood circuit according to the embodiment of the present invention.

FIG. 10 is a connection portion (opening) according to another embodiment of the present invention.
Schematic cross section showing

FIG. 11 is a schematic sectional view showing a connection portion (rubber button) according to another embodiment of the present invention.

[Explanation of symbols]

1 ... Blood circuit 1a ... Arterial blood circuit 1b ... venous blood circuit 2 ... Dializer (Blood Purifier) 2a ... blood flow path 2b ... dialysate flow path 2c ... Blood inlet 2d ... Blood outlet 2e ... Dialysate inlet 2f ... dialysis fluid outlet 3 ... Hollow fiber membrane (blood purification membrane) 4 ... Dialysis machine body 4a ... Dialysate introduction line 4b ... Dialysate discharge line 5 ... Blood pump 6 ... Flexible tube 7. Drip chamber 7a ... inlet 7b ... Outlet port 7c ... accommodation space 7d ... Air layer 7e ... Opening (connection part) 7f ... Rubber button (connection part) 8 ... Arterial shunt connector 9, 12 ... Rock ring 10, 13 ... Mounting body 11 ... Vein side shunt connector 14 ... Mesh 15 ... Auxiliary tube (connection part) 16 ... Connection means (connection part) 16a ... tubular body 16b ... flange a ... Arterial puncture needle b ... Venous puncture needle

Claims (6)

[Claims] 1. A blood circuit connected to the blood flow path of a blood purifier in which a blood flow path through which a patient's blood flows is formed, which has a blood purification membrane for purifying blood. A puncture needle is formed so that it can be attached, the base end of which can be connected to the blood introduction port in the blood flow path of the blood purifier, and the arterial blood circuit to which a blood pump can be attached in the middle, and the tip end A venous blood circuit, which is formed so that a puncture needle can be attached and whose base end is connectable to a blood outlet in the blood flow path of the blood purifier, and which is connected to a drip chamber midway, and the venous blood A blood circuit, comprising: a connection portion formed on the air layer side of the drip chamber of the circuit and capable of connecting the tip of the arterial blood circuit when returning blood. 2. The connecting portion is an auxiliary line extending from the air layer side of the drip chamber, and an arterial shunt connector provided at the tip of the auxiliary line and provided at the tip of the arterial blood circuit. The blood circuit according to claim 1, further comprising a connecting means connectable with the blood circuit. 3. The connecting portion comprises a female connector which is connectable by fluid-tightly fitting and locking the tip of an arterial shunt connector provided at the tip of the arterial blood circuit. The blood circuit according to claim 1 or 2. 4. A lock ring having a thread shape is attached to the distal end side of the arterial blood circuit, and the connecting means can be engaged with the thread shape of the lock ring to be locked. The blood circuit according to claim 2 or claim 3. 5. A rubber button provided on the air layer side of the drip chamber, the connecting portion being a rubber button connectable by puncturing the arterial puncture needle when returning blood. Blood circuit. 6. The blood purifier comprises a dialyzer in which a dialysate flow path adjacent to the blood flow path is formed via the blood purification membrane, and a dialysate inlet of the dialysate flow path in the dialyzer. The blood circuit according to any one of claims 1 to 5, wherein a dialyzer is connected to the dialysate outlet.