JPH038780B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a hollow fiber oxygenator that removes carbon dioxide from blood and adds oxygen to blood during extracorporeal blood circulation.

[Conventional technology] Conventionally, a hollow fiber oxygenator as a membrane oxygenator,
Compared to a bubble-type oxygenator, it causes less blood damage such as hemolysis, protein denaturation, blood coagulation, and blood adhesion, and is widely recognized as being mechanically very similar to a living lung.

FIG. 1 shows a blood circuit using a conventional hollow fiber oxygenator, where 1 is an oxygenator, 2 is a pump, 3 is a blood storage tank, and 4 is a heat exchanger. That is, when using the conventional hollow fiber oxygenator 1, the pump 2 is placed on the upstream side (venous side) of the oxygenator 1 when viewed in the blood flow direction.
It is set up in

[Problems to be Solved by the Invention] By the way, when the pump is not provided on the downstream side of the hollow fiber oxygenator in the blood flow direction, but is provided on the upstream side as described above, the following disadvantages occur. be.

When blood is forcibly sent toward the oxygenator, the internal pressure of the oxygenator increases, causing separation at the boundary between the hollow fiber membrane and the bulkhead material (potting material) that supports the hollow fiber membrane bundle, and blood leaks from there. or blood cells may be destroyed.

When returning blood from an artificial lung to a living body, it is preferable to use a pulsatile flow pump that discharges blood at a timing similar to the heartbeat in order to avoid stress on the living body. However, if this pump is located upstream of the oxygenator, even if there is a pulsation when it leaves the pump, the pulsation disappears when it passes through the oxygenator, and there is no pulsation when it enters the living body. will disappear.

The blood discharged from the pump needs to be returned to the living body without introducing new air bubbles. However, if an oxygenator is located downstream of the pump, there is a risk that air bubbles may be trapped there.

Therefore, in order to eliminate the above-mentioned drawbacks, an artificial lung is installed upstream of the pump in the blood flow direction, and blood perfusion in the artificial lung is achieved by the head difference between the patient and the artificial lung. It is recommended to perform head perfusion.

Here, when performing the above-mentioned head perfusion, in order to reduce the flow path resistance of the internal pressure of the circuit including the oxygenator, it is considered that the blood flows outside the hollow fiber membrane and that the packing density of the hollow fiber membrane is lowered. It will be done.

However, when an assembly of hollow fiber membranes is housed in a cylindrical housing and blood is supplied from the blood inflow port provided in the housing to the outside of the hollow fiber membranes by head perfusion, the blood inflow pressure due to the head difference is Since the pressure is relatively low, there is a disadvantage that blood is difficult to flow in the axial direction of the housing toward the side away from the blood inflow port on the cross section of the portion where the blood inflow port is provided. In other words, blood flowing into the housing from the blood inflow port collides with the hollow fiber membrane near the port and tends to move toward the blood outflow port while exchanging gas there. Since only a small amount of blood reaches the periphery of the hollow fiber membrane on the side away from the blood inflow port on the cross section of the portion where the blood inflow port is provided, it is extremely likely to accumulate in the void space around the hollow fiber membrane. Traffic jams. This means that
The blood supplied into the housing from the blood inflow port cannot be distributed uniformly in the circumferential direction of the hollow fiber membrane assembly on the cross section of the portion where the blood inflow port is provided, and the blood inflow port is not uniformly distributed in the housing. The flow rate of blood from the side to the blood outflow port side cannot be made uniform in the circumferential direction of the hollow fiber membrane assembly, creating an oxygen concentration gradient in the blood and reducing the oxygenation capacity of the oxygenator. .

In addition, when the packing density of the hollow fiber membrane is lowered, blood flows on the surface of the hollow fiber membrane and blood flows away from the surface of the hollow fiber membrane, causing oxygen in the blood flowing inside the housing. A concentration gradient is created, reducing the oxygen capacity of the oxygenator.

An object of the present invention is to enable blood perfusion due to the head difference between a patient and an artificial lung, that is, head perfusion, and to improve the oxygen capacity of the artificial lung.

[Means for Solving the Problems] The present invention includes a cylindrical housing, an assembly of hollow fiber membranes housed in the housing, and a hollow fiber membrane assembly with both ends of the hollow fiber membranes open. two partition walls that liquid-tightly hold the assembly of fiber membranes in the housing; and two partition walls located outside one of the partition walls to introduce oxygen-containing gas into the internal space of the hollow fiber membrane and allow it to flow out from the other partition wall. The housing includes a gas inflow port, and a blood inflow port and a blood outflow port provided in the housing to communicate with a blood chamber defined by the two partition walls, the inner wall of the housing, and the outer wall of the hollow fiber membrane. The inner diameter of the cross section at the portion where the blood inflow port is provided in the axial direction of the housing is larger than the inner diameter of the cross section at the axially intermediate portion of the housing, and the cross section at the portion where the blood inflow port is provided. In the above, a blood flow path is formed between the hollow fiber membrane and the outer periphery of the aggregate, where the flow path area is large on the blood inflow port side and the flow path area gradually decreases as the distance from the blood inflow port increases. This is what I did.

Further, the present invention provides that the inner diameter of the cross section in the axial direction of the housing at the portion where the blood outflow port is provided is larger than the inner diameter of the cross section in the axially intermediate portion of the housing, and the blood outflow port is On the cross section of the provided portion, there is a blood flow between the outer periphery of the aggregate of hollow fiber membranes, where the flow path area is large on the blood outflow port side and gradually decreases as the distance from the blood outflow port increases. It is designed so that a road is formed.

Further, the present invention provides that the housing has a minimum inner diameter at a substantially central portion in the axial direction, and gradually increases the inner diameter from the substantially central portion to both ends, and the outer diameter of the hollow fiber membrane bundle to be accommodated is The diameter changes along the inner wall of the housing, and is configured to be smallest at approximately the center in the axial direction of the hollow fiber membrane bundle.

Further, in the present invention, the hollow fiber membrane is a microporous membrane.

[Function] According to the present invention, the inner diameter of the cross section in the axial direction of the cylindrical housing at the portion where the blood inflow port is provided is larger than the inner diameter of the cross section in the axially intermediate portion of the housing, and On the cross section of the part where the blood inflow port is provided, it is eccentric in the direction including the blood inflow port with respect to the hollow fiber membrane assembly, and there is no blood flow between the hollow fiber membrane assembly and the outer periphery. A blood flow path is formed in which the flow path area on the inflow port side is large and the flow path area gradually decreases as the distance from the blood inflow port increases. Therefore, blood flows from the inflow port into the blood flow path of the housing at low pressure due to head perfusion, and on the side away from the inflow port on the cross section of the part where the blood inflow port is provided in the axial direction of the housing. Even when a small amount of blood arrives, the blood flow path on the side away from the inflow port will not become clogged with blood whose flow path area is gradually decreasing. As a result, the blood supplied into the housing from the blood inflow port is uniformly distributed in the circumferential direction of the hollow fiber membrane assembly on the cross section of the portion where the blood inflow port is provided, and the blood is The flow rate of blood from the inflow port side to the blood outflow port side is made uniform in the circumferential direction of the hollow fiber membrane assembly, making it possible to add oxygen to the oxygenator without creating an oxygen concentration gradient in the blood. improves. That is, blood perfusion due to the head difference between the patient and the oxygenator, that is, head perfusion, can be made possible, and the oxygen capacity of the oxygenator can be improved.

Further, according to the present invention, the inner diameter of the cross section at the portion where the blood outflow port is provided in the axial direction of the cylindrical housing is larger than the inner diameter of the cross section at the intermediate portion in the axial direction of the housing, and the blood On the cross section of the part where the outflow port is provided, it is eccentric in the direction including the blood outflow port with respect to the hollow fiber membrane assembly, and between the outer periphery of the hollow fiber membrane assembly and the blood outflow port side. An annular blood flow path is formed in which the flow path area is large and the flow path area gradually decreases as the distance from the blood outflow port increases.
Therefore, the amount of blood introduced into the blood flow path can be adjusted to the aggregate amount under conditions that ensure the safety of the living body without increasing the volume of the housing and increasing the extracorporeal blood circulation volume (priming volume) from the living body. The flow rate of blood in the axial direction of the housing within the blood chamber can be made uniform in the circumferential direction of the assembly.

Further, according to the present invention, the housing for storing the hollow fiber membrane bundle is configured such that the inner diameter is the minimum at the substantially central portion in the axial direction, and the inner diameter gradually increases from the substantially central portion to both ends. the outer diameter of the hollow fiber membrane bundle varies along the inner wall of the housing;
The hollow fiber membrane bundle is configured to be smallest at approximately the center in the axial direction. Therefore, the pressure loss within the oxygenator can be reduced, head perfusion can be performed, and the oxygen capacity of the oxygenator can be improved. This is due to the following reasons. When the hollow fiber membrane bundles are arranged in parallel without being squeezed, blood flows parallel to the hollow fiber membranes, forming a laminar flow. That is, in this case, the flow rate of blood flowing on the hollow fiber membrane surface is slow, and the further the distance from the hollow fiber membrane surface, the faster the blood flow rate, resulting in an undesirable oxygen concentration gradient in the blood. In order to create such a concentration gradient, it is necessary to increase the packing density of the entire hollow fiber membrane bundle. However, although increasing the packing density improves oxygen addition, pressure loss increases and head perfusion cannot be performed. Therefore, as in the present invention,
By squeezing the middle part of the hollow fiber membrane bundle, the blood flow is not parallel to the axis of the hollow fiber membranes but intersects with them. Therefore, turbulent flow occurs in the blood flow, especially near the middle part, and laminar flow is not formed.
Oxygen capacity is improved. Therefore, the packing density of the hollow fiber membrane can be lowered while ensuring oxygen addition, and as a result, the pressure loss can be lowered. This allows head perfusion without the use of a pump.

[Example] Fig. 2 is a circuit diagram showing a blood circuit to which the hollow fiber oxygenator according to the present invention is applied, and Fig. 3 is a sectional view showing an embodiment of the hollow fiber oxygenator according to the present invention. ,
Figure 4 is a sectional view taken along the - line in Figure 3, Figure 5 is a sectional view taken along the - line in Figure 3, and Figure 6 is a sectional view taken along the - line in Figure 3.
FIG. 3 is a sectional view taken along the - line in the figure.

As shown in FIG. 2, in the blood circuit to which the present invention is applied, an artificial lung 1 is connected from the venous side to the arterial side.
1. A blood storage tank 12, a pump 13, and a heat exchanger 14 are installed in this order.

The oxygenator 11 is constructed as shown in FIGS. 3 to 6. That is, an assembly (hollow fiber membrane bundle) 17 of hollow fiber membranes 16 is housed in the internal space of the cylindrical housing 15 . Both ends of the hollow fiber membrane 16 are connected to partition walls 18 and 1 with both ends opened.
The housing 15 is fluid-tightly held via the housing 9. Headers 2 are provided at both ends of the housing 15.
0 and 21 are joined. The inner surface of the header 20 and the partition wall 18 define a gas inflow chamber 22 communicating with the internal space of the hollow fiber membrane 16, and the header 20 is formed with a gas inflow port 23 for a gas containing oxygen. The inner surface of the header 21 and the partition wall 19 define a gas outflow chamber 24 communicating with the internal space of the hollow fiber membrane 16, and the header 21 is formed with a gas outflow port 25 for gas containing oxygen. That is, in the case of the artificial lung 11, gases such as oxygen and air supplied from the gas inflow port 23 are passed through the hollow fiber membrane 16.
It is possible to distribute within the country. In addition, the above header 2
1 is not particularly provided, and the gas flowing out from the hollow fiber membrane 16 may be directly released into the air without forming the gas outflow chamber 24 and the gas outflow port 25.

Further, the partition walls 18 and 19, the inner surface of the housing 15, and the outer surface of the hollow fiber membrane 16 define a blood chamber 26, and a blood inflow port 27 and a blood outflow port are provided at both ends of the housing 15, respectively, and communicate with the blood chamber 26. A port 28 is formed. That is, in the artificial lung 11, blood is allowed to flow around the hollow fiber membrane 16 in the blood chamber 26 in a turbulent state.

Here, the inner diameter of the cross section of the portion of the housing 15 in the axial direction where the blood inflow port 27 is provided is larger than the inner diameter of the cross section of the middle portion of the housing 15 in the axial direction. An annular blood flow channel 2 as shown in FIG.
9 is formed so that blood can be smoothly distributed to each hollow fiber membrane 16 from the entire periphery of the assembly 17 facing the blood flow path 29. Further, the expanded inner surface of the housing 15 is eccentrically arranged in a direction including the blood inflow port 27 with respect to the assembly 17 on a cross section in a portion where the blood inflow port 27 is provided. The flow path area of the blood flow path 29 facing the blood flow path 27 is larger. That is, on the cross section of the portion where the blood inflow port 27 is provided in the axial direction of the housing 15, the flow path area of the blood flow path 29 gradually decreases as the distance from the blood inflow port 27 increases. The amount of blood distributed from the housing 15 can be made uniform in the circumferential direction of the assembly 17, and the flow rate of blood in the axial direction of the housing 15 within the blood chamber 26 can be made uniform in the circumferential direction of the assembly 17.

Further, in the axial direction of the housing 15, the inner diameter of the cross section at the portion where the blood outflow port 28 is provided is larger than the inner diameter of the cross section at the middle portion of the housing 15, and the blood outflow port 28 is provided. An annular blood flow path 30 as shown in FIG. 6 is formed between the hollow fiber membranes 16 and the outer periphery of the aggregate 17 on the cross section of the hollow fiber membrane 16, and the blood around each hollow fiber membrane 16 is can be smoothly introduced toward the blood outflow port 28 from the entire periphery of the assembly 17 facing the blood flow path 30. Further, the expanded inner surface of the housing 15 is eccentrically arranged in a direction including the blood outflow port 27 with respect to the assembly 17 on a cross section in a portion where the blood outflow port 28 is provided, so that the blood outflow The flow path area of the blood flow path 30 facing the port 28 is made larger. That is, the volume of the housing 15 can be increased by gradually increasing the flow area of the blood flow path 30 toward the blood outflow port 28 on the cross section of the portion where the blood outflow port 28 is provided in the axial direction of the housing 15. Under conditions that ensure the safety of the living body without making the extracorporeal blood circulation volume (priming volume) from the living body too large,
The amount of blood introduced into the blood flow path 30 is made uniform in the circumferential direction of the aggregate 17, and the flow rate of blood in the axial direction of the housing 15 within the blood chamber 26 can be made uniform in the circumferential direction of the aggregate 17.

Furthermore, the housing 15 has a tapered shape in which the inner diameter at the center in the axial direction is the minimum, and the inner diameter gradually increases from the center to both ends, so that the outer diameter of the aggregate 17 changes along the inner wall of the housing 15. However, it is narrowed so that it is smallest at the center in the axial direction. In other words, the oxygenator 11 has the following effects:
By equalizing the blood flow in the cross section of the aggregate 17 and by changing the blood flow velocity in the axial direction of the aggregate 17, generation of turbulent flow is promoted and gas exchange efficiency can be improved. There is. The inner surface of the housing 15 is tapered, and the tapered inner surface and the inner surface defining the blood flow paths 29 and 30 are connected by a tapered connecting surface as shown in the figure. Therefore, the air that should be discharged during priming does not accumulate in the blood chamber 26 and can be removed from the housing 15.
It moves smoothly along the inner surface of the air vent and can be reliably released from an air vent port 31, which will be described later. The inner surface of the housing 15 may be tapered, for example, so that the diameter increases linearly from the blood inflow port 27 side of the blood chamber 26 toward the blood outflow port 28 side. In addition, the artificial lung 11A shown in FIG.
As shown in , when the inner surface of the housing 15A defining the blood chamber 26A has portions P1 and P2 that protrude discontinuously in the blood flow direction,
Air at the time of priming causes these protruding parts P1, P
2, and the air cannot be completely exhausted from the blood chamber 26A, which is not appropriate.

Here, a microporous membrane is used as the hollow fiber membrane 16. That is, the hollow fiber membrane 16
is made of porous polyolefin resin, such as polypropylene and polyethylene,
Particularly suitable is polypropylene. This hollow fiber membrane 16 has a large number of pores that communicate between the inside and outside of the wall. The inner diameter of the pores is about 100-1000μ, the wall thickness is about 10-50μ, the average pore diameter is about 200-2000Å, and the porosity is 20-80%. When using the hollow fiber membrane 16 made of this microporous membrane, gas movement is performed as a volumetric flow, so the membrane resistance in gas movement is reduced, making it possible to obtain high gas exchange performance. Note that the hollow fiber membrane 16
The method is not necessarily based on a microporous membrane, but may be one using a silicone membrane or the like in which gas movement is performed by dissolution and diffusion.

Incidentally, the partition walls 18 and 19 are formed by the following centrifugal injection method. That is, first, a large number of hollow fiber membranes 16 that are longer than the length of the housing 15 are prepared, and after sealing both open ends with a resin with high viscosity, the housing 15 is closed.
Place them side by side inside. After this, the hollow fiber membrane 16
While rotating the housing 15 around the rotation center defined in the longitudinal direction of the housing 15 with the central axis of the housing 15 placed in the radial direction of rotation, the blood inflow port 27
The polymer potting material flows in from the blood outflow port 28 side. Once the resin has hardened after pouring, cut the outer end of the resin with a sharp knife to remove the hollow fiber membrane 16.
The partition walls 18 and 19 are formed by exposing both open ends of the partition walls 18 and 19 to the surface. Therefore, bulkhead 1
The surfaces of the blood chambers 8 and 19 facing the blood chamber 26 are cylindrical concave surfaces as shown in FIGS. 3 and 4.

In addition, in the above embodiment, the housing 15
An air vent port 31 is provided which is located above the blood outflow port 28 and communicates with the inside of the blood chamber 26 under use. The air vent port 31 is equipped with a removable breathable and bacteria-impermeable filter 32, which is removed during priming and attached after priming to prevent bacteria from forming in the oxygenator 11 when the air generated during use of the oxygenator is removed. This makes it possible to prevent contamination.

The air vent port 31 allows the air in the blood circuit and the oxygenator 11 to be discharged to the outside by a filling liquid such as physiological saline during priming, and after discharge is fitted with a stopper and hermetically sealed. It is considered possible.

Next, the operation of the above embodiment will be explained.

An artificial lung is used, for example, in open heart surgery, and is installed in the middle of a blood circulation circuit (FIG. 2). Note that blood is usually taken out at a flow rate of 4/min.

First, before blood flows into the oxygenator 11, physiological saline mixed with heparin is poured into the blood inflow port 28.
All the air in the blood chamber 26 in the oxygenator 11 is removed. At this time, the tube connected to the blood reservoir is connected to the air vent port 31 (remove the filter 32), and the blood outflow port 28 is
Connect the tube in the same way as the air vent port 31, or if not, seal it with a cap or the like. After air removal from the oxygenator 11 is completed, a filter 32 is attached to the air removal port 31 and sealed with a cap (not shown). The blood that has been removed with a certain height (approximately 1 m) is transferred to the oxygenator 1.
The blood flows in from the blood inflow port 27 of No. 1. The inflowing blood hits the outer wall of the hollow fiber 16 near the blood inflow port 27, flows through an annular blood flow path 29 provided inside the oxygenator, and rises in the blood chamber 26 due to the gravity given by the drop. In addition, gas containing oxygen such as oxygen and air flows through the gas inlet port 2.
3 into the hollow fiber membrane 16. This gas passes through the hollow fiber membrane 16 and is discharged to the outside from the gas outlet port 25. At this time, the blood exchanges oxygen flowing in from the gas inflow port via the hollow fiber membrane 16 with carbon dioxide in the blood. The oxygenated blood then flows out from the blood outflow port 28 through the blood flow path 30 and is stored in the blood storage tank 12.
The blood is heated or cooled to an appropriate temperature through the blood pump 13 and the heat exchanger 14, and is then sent to the human body.

According to the above embodiment, the inner surface of the portion of the cylindrical housing 15 where the blood inflow port 27 is provided expands outward from the inner surface of the axially intermediate portion of the housing 15, and the hollow fiber membrane 16 is eccentric in a direction including the blood inflow port 27 with respect to the aggregate 17, and the flow path area on the blood inflow port 27 side is large between the hollow fiber membrane 16 and the outer periphery of the aggregate and moves away from the blood inflow port 27. Accordingly, an annular blood flow path 29 is formed whose flow path area gradually decreases.
Therefore, blood flows from the inflow port 27 to the annular blood flow path 2 of the housing 15 at low pressure due to head perfusion.
Even when a small amount of blood flows into the blood flow path 9 and reaches the side away from the inflow port 27, the blood flow path 29 on the side away from the inflow port 27 gradually decreases its flow path area to prevent blood congestion. There is no. As a result, blood supplied from the blood inflow port 27 to the housing 15 is uniformly distributed in the circumferential direction of the assembly 17 of the hollow fiber membranes 16, and
5, the flow rate of blood toward the blood outflow port 28 is made uniform in the circumferential direction of the assembly 17 of the hollow fiber membranes 16. It is possible to improve performance. That is, the patient and the oxygenator 1
This makes it possible to perform blood perfusion with a head difference of 1, that is, head perfusion, and improve the oxygen capacity of the artificial lung 11.

Furthermore, since the blood flow path on the inflow port 24 side is large, the distance between the inflow port 27 and the hollow fiber bundle is long, and the force of the blood flowing in from the inflow port 27 is weakened until it reaches the hollow fiber bundle. Blood can be prevented from selectively flowing into the inflow port 27 side portion of the hollow fiber bundle. That is, the flow of blood from the outer periphery of the hollow fiber bundle in the axial direction of the hollow fiber bundle can be made uniform around the outer periphery. Furthermore, the farther from the inflow port 27, the smaller the blood flow path area becomes, so the flow path area corresponds to changes in blood volume around the outer periphery of the hollow fiber bundle. can be reduced. In other words, the extracorporeal circulating blood volume (priming volume) can be reduced.

Further, in the above embodiment, the inner diameter of the cross section at the portion where the blood outflow port 28 is provided in the axial direction of the cylindrical housing 15 is larger than the inner diameter of the cross section at the intermediate portion in the axial direction of the housing 15. and is eccentric in the direction including the blood outflow port 28 with respect to the aggregate 17 of the hollow fiber membranes 16 on the cross section of the part where the blood outflow port 28 is provided, and the outer periphery of the aggregate of the hollow fiber membranes 16 An annular blood flow path 30 is formed between the blood outflow port 28 and the blood outflow port 28. Therefore, the amount of blood introduced into the blood flow path 30 can be controlled under conditions that ensure the safety of the living body without making the volume of the housing 15 too large and thereby increasing the extracorporeal blood circulation volume (priming volume) from the living body. The blood chamber 2 is made uniform in the circumferential direction of the aggregate 17.
The flow rate of blood in the axial direction of the housing 15 within the housing 15 can be made uniform in the circumferential direction of the aggregate 17.

Further, according to the above embodiment, the housing 15 that houses the assembly 17 as a hollow fiber membrane bundle has a minimum inner diameter at the substantially central portion in the axial direction, and gradually increases the inner diameter from the substantially central portion to both ends. The outer diameter of the aggregate 17 to be housed changes along the inner wall of the housing 15, and is configured to be smallest at approximately the center of the aggregate 17 in the axial direction. Therefore, the pressure loss of the artificial lung 11 can be reduced, head perfusion can be performed, and the oxygen capacity of the artificial lung 11 can be improved. That is, by squeezing the middle part of the aggregate 17, the blood flow is directed to the hollow fiber membrane 1.
It will not be parallel to the axis of 6, but will intersect with it. Therefore, turbulent flow occurs in the blood flow, particularly near the middle portion, and a laminar flow is not formed, thereby improving oxygenation. Therefore, the packing density of the hollow fiber membranes 16 can be lowered under conditions that ensure oxygen addition, and as a result, pressure loss can be lowered. This allows head perfusion without the use of a pump.

Therefore, blood perfusion due to the head difference between the patient and the artificial lung 11, that is, head perfusion, can be made possible, and the oxygen capacity of the artificial lung 11 can be improved.

[Effects of the Invention] As described above, according to the present invention, it is possible to perform blood perfusion due to the head difference between the patient and the artificial lung, that is, head perfusion, and to improve the oxygen capacity of the artificial lung.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a blood circuit to which a conventional membrane oxygenator is applied, and FIG. 2 is a circuit diagram showing a blood circuit to which a hollow fiber oxygenator according to the present invention is applied. FIG. 3 is a sectional view showing an embodiment of the hollow fiber oxygenator according to the present invention, and FIG.
5 is a sectional view taken along the - line in FIG. 3, FIG. 6 is a sectional view taken along the - line in FIG. 3, and FIG. 7 shows a conventional hollow fiber oxygenator. FIG. 11...Artificial lung, 15...Housing, 16...
... hollow fiber membrane, 17 ... aggregate, 18, 19 ... partition, 23 ... gas inflow port, 26 ... blood chamber,
27...Blood inflow port, 28...Blood outflow port, 29, 30...Blood flow path.

Claims (1)

[Scope of Claims] 1. A cylindrical housing, an assembly of hollow fiber membranes housed in the housing, and an assembly of hollow fiber membranes as described above with both ends of the hollow fiber membranes open. two partition walls held liquid-tightly in the housing; a gas inflow port located outside one of the partition walls for introducing oxygen-containing gas into the internal space of the hollow fiber membrane and flowing out from the other partition wall; a blood inflow port and a blood outflow port provided in the housing so as to communicate with a blood chamber defined by two partition walls, the inner wall of the housing, and the outer wall of the hollow fiber membrane; The inner diameter of the cross section at the portion where the blood inflow port is provided is larger than the inner diameter of the cross section at the axially intermediate portion of the housing, and on the cross section at the portion where the blood inflow port is provided, the hollow fiber membrane A hollow fiber artificial prosthesis characterized in that a blood flow path is formed between the outer peripheral part of the aggregate and the flow path area is large on the blood inflow port side and gradually decreases in flow path area as the distance from the blood inflow port increases. lung. 2. A portion where the inner diameter of the cross section of the portion of the housing in the axial direction where the blood outflow port is provided is larger than the inner diameter of the cross section of the axially intermediate portion of the housing, and where the blood outflow port is provided. On the cross section at A hollow fiber oxygenator according to claim 1. 3. The housing has a minimum inner diameter at a substantially central portion in the axial direction, and the inner diameter gradually increases from the substantially central portion to both ends, and the outer diameter of the hollow fiber membrane bundle to be accommodated is within the inner wall of the housing. 3. The hollow fiber oxygenator according to claim 1 or 2, wherein the hollow fiber oxygenator is configured to change along the axial direction of the hollow fiber membrane bundle and to be smallest at approximately the center in the axial direction of the hollow fiber membrane bundle. 4. The hollow fiber oxygenator according to any one of claims 1 to 3, wherein the hollow fiber membrane is a microporous membrane.