JPS6237992B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber oxygenator that removes carbon dioxide from blood and adds oxygen to blood during extracorporeal blood circulation.

Prior Art Conventionally, artificial lungs are broadly classified into bubble type and membrane type. Membrane oxygenators such as stacked, coil, and hollow fiber types cause less blood damage such as hemolysis, protein denaturation, blood coagulation, and blood adhesion than bubble oxygenators, and are mechanically very effective against biological lungs. It is widely recognized as being similar.

However, despite the superiority of the membrane oxygenator over the bubble oxygenator, the bubble oxygenator is currently the mainstream oxygenator used in open heart surgery due to the following disadvantages of the membrane oxygenator. ing.

In current membrane oxygenators, in order to obtain sufficient oxygenation capacity, the blood layer needs to be thinned, resulting in a narrow blood flow path and a large flow resistance. It is not possible to perform so-called head perfusion, which makes it possible to achieve blood perfusion in the oxygenator by a head difference between the artificial lung and the artificial lung. Therefore, in a blood circuit using a membrane oxygenator, it is necessary to arrange a pump 2 on the inlet side of the oxygenator 1, that is, on the venous side, as shown in FIG. In addition, in FIG. 1, 3 is a blood storage tank, and 4 is a heat exchanger. However, in the blood circuit shown in FIG.
There was a problem in that the pressure near the outlet of the blood-transfer catheter exceeded the sum of the pressure loss in the blood-transfer catheter section and the pressure loss in the oxygenator, and the pressure inside the blood-transfer side circuit rose. Therefore, attempts have been made to allow blood to flow outside the hollow fibers, but this method has not been able to be used effectively due to difficulties in priming, etc.

Purpose of the Invention The present invention makes it possible to improve gas exchange efficiency per unit membrane area, and also enables blood perfusion due to the head difference between the patient and the oxygenator, that is, head perfusion.
Another object of the present invention is to provide a hollow fiber oxygenator that can effectively remove air generated during priming and use.

Structure of the Invention The above object is achieved by a housing, an assembly of hollow fiber membranes housed in the housing, and two membranes that are held liquid-tight in the housing with both ends of the hollow fiber membranes open. A gas inflow port for oxygen-containing gas that communicates with the internal space of the hollow fiber membrane is provided on the outside of one of the partition walls, and the oxygen-containing gas that flows in from the gas inflow port flows through the hollow fiber membrane from one of the partition walls. A blood inflow port provided in the housing allows blood to flow into the membrane and then flow out from the other partition wall, and further communicates 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. and a hollow fiber oxygenator comprising a blood outflow port, and an air vent port located above the blood outflow port in use and communicating with the liquid chamber to exhaust air from the blood chamber to the outside. .

Further, in the hollow fiber oxygenator according to the present invention, the air vent port and the blood outflow port are provided at substantially axially symmetrical positions with respect to the housing.

Further, in the hollow fiber oxygenator according to the present invention, the air vent port is provided in a side wall of the housing at a portion in contact with a concave bottom portion of the partition wall.

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

Further, in the hollow fiber oxygenator according to the present invention, the inner surface of the portion of the housing where the blood inflow port is provided is an inner surface expanded outward from the inner surface of the intermediate portion of the housing, and the hollow fiber membrane is An annular blood flow path is formed between the blood flow path and the outer circumference of the aggregate.

Further, in the hollow fiber oxygenator according to the present invention, the inner surface of the portion of the housing where the blood outflow port is provided is an inner surface expanded outward from the inner surface of the intermediate portion of the housing, and the hollow fiber membrane is An annular blood flow path is formed between the blood flow path and the outer circumference of the aggregate.

Further, in the hollow fiber oxygenator according to the present invention, the expanded inner surface of the housing is eccentrically arranged in a direction including the blood inflow port with respect to the assembly of hollow fiber membranes, and the blood flow facing the blood inflow port is The channel has a larger flow area.

Further, in the hollow fiber oxygenator according to the present invention, the expanded inner surface of the housing is eccentrically arranged in a direction including the blood outflow port with respect to the assembly of hollow fiber membranes, and the blood flow facing the blood outflow port is arranged eccentrically in a direction including the blood outflow port. The channel has a larger flow area.

Further, in the hollow fiber oxygenator according to the present invention, the air vent port is an air vent port having a filter that is breathable and impermeable to bacteria.

Detailed Description of the Invention Fig. 2 is a circuit diagram showing a blood circuit to which the hollow fiber oxygenator according to the invention is applied, and Fig. 3 is a cross section showing an embodiment of the hollow fiber oxygenator according to the invention. figure,
Figure 4 is a sectional view taken along the - line of the third number, Figure 5 is a sectional view taken along the - line of Figure 3, and Figure 6 is a sectional view taken along the - line of the third number.
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.
A blood storage tank 12, a pump 13, and a heat exchanger 14 are sequentially installed.

The oxygenator 11 is constructed as shown in FIGS. 3 to 6. That is, an assembly 17 of hollow fiber membranes 16 is housed in the inner space of the cylindrical housing 15 . Both ends of the hollow fiber membrane 16 are fluid-tightly held in the housing 15 via partition walls 18 and 19 with both ends open. Headers 20 and 21 are joined to both ends of the housing 15. The inner surface of the header 20 and the partition wall 18 are
Gas inflow chamber 2 communicating with the internal space of the hollow fiber membrane 16
2, and a gas inlet port 23 for a gas containing oxygen is formed in the header 20. 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 has a gas outflow port 25 containing oxygen.
is formed. That is, in the case of the artificial lung 11, gases such as oxygen and air supplied from the gas inflow port 23 are allowed to flow into the hollow fiber membrane 16. Note that the header 21 may not be particularly provided, and the gas flowing out from the hollow fiber membrane 16 may be directly released into the atmosphere 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 surface of the portion of the housing 15 where the blood inflow port 27 is provided is an inner surface that expands outward from the inner surface of the intermediate portion of the housing 15, and is the outer peripheral surface of the aggregate 17 of the hollow fiber membranes 16. An annular blood flow path 29 as shown in FIG. 5 is formed between the two hollow fiber membranes 16, so that blood can be smoothly distributed to each hollow fiber membrane 16 from the entire periphery of the assembly 17 that the blood flow path 29 faces. The expanded inner surface of the housing 15 also provides a blood inflow port 27 for the assembly 17.
The blood inflow port 27 is eccentrically arranged in a direction including
The flow path area of the blood flow path 29 facing the blood flow path is larger. That is, the flow area of the blood flow path 29 is gradually decreased as it moves away from the blood inflow port 27, and the amount of blood distributed from the blood flow path 29 is reduced to the aggregate 1.
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.

In addition, the blood outflow port 2 of the housing 15
The inner surface of the portion where 8 is provided is the housing 1
As shown in FIG. 6, an annular blood flow path 30 is formed between the inner surface extending outward from the inner surface of the intermediate portion of the hollow fiber membrane 16 and the outer peripheral portion of the aggregate 17 of the hollow fiber membranes 16. Blood around each hollow fiber membrane 16 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 arranged eccentrically in the direction including the blood outflow port 28 with respect to the assembly 17, thereby making the flow path area of the blood flow path 30 facing the blood outflow port 28 larger. . That is, by gradually increasing the flow area of the blood flow path 30 toward the blood outflow port 28, the blood flow path 30
The amount of blood introduced into the blood chamber 26 is made uniform in the circumferential direction of the assembly 17, and the housing 15 is
The flow rate of blood in the axial direction of the aggregate 17 can be made uniform in the circumferential direction of the aggregate 17.

Further, the housing 15 has a tapered shape in which the inner diameter is minimized at the center in the axial direction, and the inner diameter gradually increases from the center to both ends, and the outer diameter of the assembly 17 is narrowed at the center in the axial direction. It's on. That is, the artificial lung 11 is
The constriction of the aggregate 17 applied by the aggregate 17 equalizes the blood flow in the cross-sectional view of the aggregate 17, and promotes the generation of turbulent flow by changing the blood flow velocity in the axial direction of the aggregate 17. death,
The gas exchange efficiency can be improved. 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 to be discharged during briming can smoothly move along the inner surface of the housing 15 without remaining in the blood chamber 26, and can be reliably discharged from the air vent port 31, which will be described later. For example, the inner surface of the housing 15 is connected to the blood inflow port 2 of the blood chamber 26.
It may also have a tapered shape that linearly increases in diameter from the 7 side toward the blood outflow port 28 side.
Note that, as in the artificial lung 11A shown in FIG. 7, when the inner surface of the housing 15A that defines the blood chamber 26A has portions P1 and P2 that protrude discontinuously in the blood flow direction, when brimming Air is trapped by the protrusions P1, P2, and it is not possible to completely exhaust the air from the blood chamber 26A.

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.

Therefore, in the embodiment described above, the housing 15 is provided with an air vent port 31 that is located above the blood outflow port 28 under use and communicates with the inside of the blood chamber 26. The air vent port 31 has a removable breathable and bacteria-impermeable filter 3.
2 is attached, which is removed during priming and attached after priming, to prevent contamination of the oxygenator 11 with bacteria when air generated during use of the oxygenator is removed.

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. Note that the air vent port 3
1 and the blood outflow port 28 are provided in axially symmetrical positions with respect to the housing 15, and during priming, as shown in FIG.
By slanting the air vent port 31 in a plane including the blood outflow port 28, the air vent port 31 is positioned vertically above the blood outflow port 28, thereby making air evacuation more reliable and easy. Further, the air vent port 31 is provided at a portion of the side wall of the housing 15 that contacts the bottom of the concave surface of the partition wall 18, and
It is connected to the uppermost part of the oxygenator, and enables complete exhaustion of air during priming and air generated during use, such as when air remaining in the blood circuit junction etc. flows into the oxygenator during use. It is said that Note that the air vent port is connected to the partition wall 18.
It may be provided so as to penetrate through the center of the.

Specific Effects of the Invention 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, connect a tube connected to the blood storage tank to the air vent port 31 (remove the filter 32), and connect a tube to the blood outflow port 28 in the same way as the air vent port 31, or if not, connect a cap, etc. Seal with.
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). Certain head difference (1
The blood that has been drained at a rate of about 100 m) is allowed to flow in from the blood inflow port 27 of the oxygenator 11. 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. Also, oxygen,
A gas containing oxygen, such as air, is supplied into the hollow fiber membrane 16 from the gas inlet port 23 . This gas passes through the hollow fiber membrane 16 and passes through the gas outlet port 25.
is discharged to the outside. At this time, the blood flows through the hollow fiber 1
6, the oxygen flowing in from the gas inlet port and the carbon dioxide in the blood are exchanged. The oxygenated blood flows out from the blood outflow port 28 through the blood flow path 30, is stored in the blood storage tank 12, and is heated or cooled to an appropriate temperature through the blood pump 13 and the heat exchanger 14. Blood is sent to the human body.

Then, air generated in the oxygenator 11 during blood feeding (mainly remaining in the tube connection part of the blood circuit) flows in from the blood inflow port 27 like blood, ascends the blood chamber 26, and enters the blood flow path 30. The liquid is stored in the recess of the partition wall 18 at the upper end of the partition wall 18. Then, the cap of the air vent port 31 is removed and the stored air is released through the filter 32 to the outside.

At this time, it is preferable to tilt the oxygenator 11 as shown in FIG. 8 so that the air vent port 31 is located above the blood outflow port.

Specific Effects of the Invention As described above, the hollow fiber oxygenator according to the present invention includes a housing, an assembly of hollow fiber membranes housed in the housing, and a state in which both ends of the hollow fiber membranes are open. and two partition walls that are held liquid-tight in the housing, and a gas inflow port for a gas containing oxygen that communicates with the internal space of the hollow fiber membrane is provided on the outside of one of the partition walls, and the oxygen that flows in from the gas inflow port is provided. The gas containing the gas flows into the hollow fiber membrane through one partition wall and then flows out from the other partition wall, and further communicates 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 housing includes a blood inflow port and a blood outflow port provided in the housing, and an air vent port that is located above the blood outflow port in use and communicates with the blood chamber to exhaust air from the blood chamber to the outside. This makes it possible to improve the gas exchange efficiency per unit membrane area by performing gas exchange under turbulent blood flow conditions, and to improve the gas exchange efficiency per unit membrane area. It becomes possible to realize blood perfusion due to the head difference between the artificial lung and the artificial lung, that is, head perfusion.

Further, in the hollow fiber oxygenator according to the present invention, the air vent port and the blood outflow port are provided at positions that are approximately axially symmetrical with respect to the housing, so that when priming, the oxygenator By tilting the center axis in the plane that includes the air vent port and the blood outflow port, the gas vent port is positioned vertically above the blood outflow port, making air evacuation more reliable and easier. It becomes possible to do so.

Further, in the hollow fiber oxygenator according to the present invention, the air vent port is provided in a side wall of the housing at a portion in contact with the concave bottom of the partition wall, so that the air vent port is communicated with the uppermost portion of the blood chamber, and priming is performed. This allows for a more complete evacuation of air during use or of air generated during use.

Further, in the hollow fiber oxygenator according to the present invention, the hollow fiber membrane is made of a microbolus membrane, thereby reducing membrane resistance in gas movement and improving gas exchange performance. Become.

Further, in the hollow fiber oxygenator according to the present invention, the inner surface of the portion of the housing where the blood inflow port is provided is an inner surface expanded outward from the inner surface of the middle portion of the housing, and the hollow fiber membrane By forming an annular blood flow path between the blood flow path and the outer periphery of the aggregate, blood can be smoothly distributed to each hollow fiber membrane from the entire periphery of the aggregate that the blood flow path faces.

Further, in the hollow fiber oxygenator according to the present invention, the inner surface of the portion of the housing where the blood outflow port is provided is an inner surface expanded outward from the inner surface of the intermediate portion of the housing, and the hollow fiber membrane is By forming an annular blood flow path between the outer periphery of the aggregate, blood around each hollow fiber membrane can be smoothly introduced toward the blood outflow port from the entire periphery of the aggregate facing the blood flow path. becomes.

Further, in the hollow fiber oxygenator according to the present invention, the expanded inner surface of the housing is eccentrically arranged in a direction including the blood inflow port with respect to the assembly of hollow fiber membranes, and the blood flow facing the blood inflow port is By increasing the flow area of the channel, the amount of blood distributed from the blood flow channel is made uniform in the circumferential direction of the assembly, and the flow rate of blood in the axial direction of the housing in the blood chamber is increased. It becomes possible to make the aggregate 17 uniform in the circumferential direction.

Further, in the hollow fiber oxygenator according to the present invention, the expanded inner surface of the housing is eccentrically arranged in a direction including the blood outflow port with respect to the assembly of hollow fiber membranes, and the blood flow facing the blood outflow port is arranged eccentrically in a direction including the blood outflow port. By increasing the flow area of the channel, the amount of blood introduced into the blood flow channel is made uniform in the circumferential direction of the assembly, and the flow rate of blood in the axial direction of the housing in the blood chamber is increased. It becomes possible to make the aggregate uniform in the circumferential direction.

Further, in the hollow fiber oxygenator according to the present invention, the air vent port is an air vent port having a removable breathable and bacteria-impermeable filter. This makes it possible to prevent contamination by bacteria.

[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. 8 is a cross-sectional view showing the arrangement state of the hollow fiber oxygenator according to the present invention at the time of priming. 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, 31...Air vent port.

Claims (1)

[Scope of Claims] 1. A housing, an assembly of hollow fiber membranes housed in the housing, and two partition walls that hold the hollow fiber membranes in a fluid-tight manner in the housing with both ends open. A gas inflow port for oxygen-containing gas that communicates with the internal space of the hollow fiber membrane is provided on the outside of one of the partition walls, and the oxygen-containing gas that flows from the gas inflow port flows into the hollow fiber membrane from one of the partition walls. A blood inflow port and a blood outflow port provided in the housing 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. and an air vent port that is located above the blood outflow port and communicates with the blood chamber to discharge air from the blood chamber to the outside under use. 2. The hollow fiber oxygenator according to claim 1, wherein the air vent port and the blood outflow port are provided at substantially axially symmetrical positions with respect to the housing. 3. The hollow fiber oxygenator according to any one of claims 1 to 2, wherein the air vent port is provided in a side wall of the housing at a portion that contacts the concave bottom of the partition wall. 4. The hollow fiber oxygenator according to any one of claims 1 to 3, wherein the hollow fiber membrane is a microporous membrane. 5. The inner surface of the portion of the housing where the blood inflow port is provided is an inner surface that extends outward from the inner surface of the intermediate portion of the housing, and has an annular blood flow between it and the outer periphery of the hollow fiber membrane assembly. A hollow fiber oxygenator according to any one of claims 1 to 4, which forms a channel. 6. The inner surface of the portion of the housing where the blood outflow port is provided is an inner surface that extends outward from the inner surface of the intermediate portion of the housing, and has an annular blood flow between it and the outer periphery of the hollow fiber membrane assembly. A hollow fiber oxygenator according to any one of claims 1 to 5, which forms a channel. 7. A patent in which the expanded inner surface of the housing is arranged eccentrically in a direction including the blood inflow port with respect to the assembly of hollow fiber membranes, and the flow path area of the blood flow path facing the blood inflow port is larger. A hollow fiber oxygenator according to claim 5. 8. A patent in which the expanded inner surface of the housing is eccentrically arranged in a direction including the blood outflow port with respect to the assembly of hollow fiber membranes, and the flow path area of the blood flow path facing the blood outflow port is larger. A hollow fiber oxygenator according to claim 6. 9. The hollow fiber oxygenator according to any one of claims 1 to 8, wherein the air vent port has a removable breathable and germ-impermeable filter.