JPH04129565A - Hollow yarn model oxygenator - Google Patents

Abstract

PURPOSE:To reduce the blood filling quantity and miniaturize a device by providing a circular blood feed passage communicated to the inner space of an outer tube and liquid-tightly independent from the second cap, and providing a blood circular passage communicated to a blood outlet on the periphery section near the upper end section of an outer tube. CONSTITUTION:Blood is guided into the blood passage 31 of an exchanger 27 through a blood inlet 10, and it is heat-exchanged with the water flowing in a water passage 29 to the preset temperature. It is then guided into a circular chamber 15 through a blood circular feed passage 13, part of the blood enters a hollow yarn circular bundle 11, and the other portion flows into gaps 6 formed between an inner tube 12 and the hollow yarn circular bundle 11. The blood is gradually spread to the whole hollow yarn circular bundle 11, it flows on the outside of a hollow yarn film and reaches a blood circular passage 17 provided on the periphery section near the upper end section of an outer tube 14, then it is discharged from a blood outlet 18. The blood is gas-exchanged with the oxygen-containing gas guided through a gas inlet 19 and flowing in the hollow yarn film while it flows in the whole hollow yarn circular bundle 11, oxygen is added to the blood, and carbon dioxide is removed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hollow fiber membrane oxygenator using a so-called blood external perfusion method, in which blood flows outside the hollow fiber membrane and oxygen-containing gas is introduced inside the hollow fiber membrane. More specifically, the present invention relates to a hollow fiber membrane type artificial joint that can achieve a good balance of low pressure loss, prevention of blood channeling (a phenomenon in which blood flows locally and unevenly), and improvement of gas exchange efficiency.

[Prior art and problems to be solved by the invention] There are two types of oxygenators: bubble type and demolded type.Compared to the bubble type, oxygenators use a membrane that uses a gas exchange membrane. It has the advantage of being highly effective and having little adverse effect on the blood.

Demolding oxygenators mainly use hollow fiber membranes to perform blood gas exchange through the hollow fiber membranes.

In addition, as methods for blood to flow into the oxygenator, there are two methods: internal perfusion, in which blood flows inside the hollow fiber membrane and gas flows outside the hollow fiber membrane, and conversely, blood flows outside the hollow fiber membrane, and gas flows through the hollow fiber membrane. There is an external perfusion method in which the blood is perfused inside the body. The former is tens to hundreds of μm
Because blood flows inside the thin hollow fiber membrane, the pressure loss during blood circulation increases, and it is said that damage to the blood (blood cell damage) may occur. Furthermore, centrifugal pumps and pulsatile flow pumps have become popular in recent years, and in order to enable extracorporeal circulation with these pumps, it is desirable that the pressure loss in the artificial lung be small. On the other hand, the latter method is more advantageous than the former method in terms of pressure loss, blood cell damage, etc., but because the flow path for blood can be freely provided, uneven flow of blood is likely to occur. Furthermore, when attempting to improve gas exchange efficiency and uneven blood flow by increasing the filling rate of the hollow fiber membrane, pressure loss increases.

In this case, if an attempt is made to solve the above problem by increasing the membrane area, the amount of blood filled in the oxygenator will increase, making extracorporeal circulation without blood transfusion difficult.

The above-mentioned problems are greatly influenced by the way the hollow fiber membranes are arranged, the filling rate, the blood inlet/output 11 positions, the way the blood flows, and the like. Conventional countermeasures have been to improve gas exchange efficiency and pressure loss by increasing the membrane area and channel area, and to flow blood from the side of the hollow fiber bundle to reduce pressure loss. There are known methods for achieving this. However, compared to the internal perfusion method, the latter method provides low pressure loss and is difficult to adapt to pulsatile flow pumps, etc., and the former method has low pressure loss, but
The drawback is that the blood filling volume is large.

On the other hand, as a method for distributing hollow fiber membranes, in order to prevent uneven flow of blood and obtain high gas exchange ability, it has been proposed to wrap hollow fiber membranes around a core-like material. At the blood inlet (the part where blood is introduced into the hollow fiber bundle), blood entering from the blood boat suddenly enters the hollow fiber bundle, and the wave path is also suddenly narrowed, resulting in a large pressure loss.

Furthermore, if a structure is adopted in which the blood inlet is made wider to prevent this, one oxygenator will become larger.

Therefore, an object of the present invention is to provide a hollow fiber membrane oxygenator that solves the above-mentioned conventional problems.

[Means for Solving the Problems] According to the present invention, the object is to form one or more gas-permeable hollow fiber membranes having a space in the center by converging and distributing them in a cross-wound shape. The cylindrical hollow fiber annular bundle is housed in an outer cylinder, and an inner cylinder having a diameter smaller than the diameter of the cylindrical space is inserted into the cylindrical space inside the hollow fiber annular bundle. The bundle is supported by a partition wall so as to close both ends of the outer cylinder and one end of the inner cylinder so that both ends of the hollow fiber membrane are open, and the first partition wall that closes the ends of both the outer cylinder and the inner cylinder is hollow. A hollow fiber membrane is attached to the second partition, which is crowned with a first cap having an inlet or an outlet for oxygen-containing gas that communicates with the inner space of the fiber membrane, and which closes the end of the outer cylinder but does not close the end of the inner cylinder. A second cap having an inlet or an outlet for oxygen-containing gas that communicates with the inner space is mounted thereon, and an annular blood supply passage that communicates with the inner space of the outer cylinder and is fluidly independent of the second cap. This can be achieved by a hollow fiber membrane oxygenator in which a blood annular passage communicating with a blood outlet is provided at the peripheral edge of the outer cylinder near the upper end thereof.

Further, in the present invention, a blood inlet or outlet is provided in the center of the second partition, communicating with the annular chamber formed between the outer cylinder and the inner cylinder, and being fluid-tightly independent of the first cap. That's preferable.

Furthermore, in the present invention, it is preferable that the end portion of the hollow fiber annular bundle on the side supported by the first partition wall is located on the same plane as the outer surface of the first partition wall or is located inside it (i.e., shortened); Further, it is preferable that the end of the inner cylinder (inner core) on the second partition wall side be formed to have a convex shape in order to smoothly introduce blood into the annular chamber.

Furthermore, in the present invention, it is preferable to integrally provide the heat exchanger section with the above-described structure in order to make the entire system more efficient and compact.

The cylindrical hollow fiber (fiber) annular bundle in the oxygenator of undeveloped IJi has a gas-permeable hollow fiber membrane as an outer cylinder (outer casing).
It is preferable to manufacture the hollow fiber membrane by winding it at an angle of 1008 to 130 degrees with respect to the longitudinal direction of the hollow fiber membrane, so that the gas exchange ability and other performance of the hollow fiber membrane can be fully exhibited.

In addition, in the present invention, the inner cylinder (inner core) and the hollow fiber (fiber #
I) The gap provided between the inner cylinder and the annular bundle is 1 mm to 1 Oem on one side from the inner cylinder to the inner surface of the hollow fiber (fiber) annular bundle.
A certain degree is preferable, and a range of 2 layers to 5 inches is more preferable. Further, the gap does not necessarily need to be constant between the inner cylinder and both ends of the hollow fiber (fiber #I) annular bundle, but it is preferable that it be constant.

Further, the diameter of the annular surface liquid sending passage in the present invention is at least 5 degrees smaller than the outer diameter of the inner cylinder, and
Preferably, the range is up to the inner diameter of the annular bundle.

In addition, in order to facilitate degassing during briming, a small carbon dioxide cartridge was installed to prefill the oxygenator lung and/or blood circuit with carbon dioxide.
It is preferable in terms of use to integrate the li into the li and fill the oxygenator and/or blood circuit with carbon dioxide before priming.

[Effect] The operation of the artificial lung of the present invention will be explained with reference to FIG.

Blood passes through blood population 10 and hollow fiber (fiber) circular bundle 11
The outer cylinder 14 and the inner cylinder 12 are connected from the blood annular feeding passage 13 provided at the bottom of the inner cylinder 12, which has a smaller diameter than the inner cylindrical space.
Some of the blood enters the annular chamber 15 formed between the inner cylinder 12 and the hollow fiber annular bundle 11, and the other blood enters the gap 16 formed between the inner tube 12 and the hollow fiber annular bundle 11. The blood then gradually spreads throughout the hollow fiber annular bundle 11, flows outside the hollow fiber membrane within the hollow fiber annular bundle 11, and flows into the blood provided at the periphery near the upper end of the outer cylinder 14. After reaching the annular passage 17, the blood is discharged from the blood outlet 18.

While the blood flows through the entire hollow fiber annular bundle 11 as described above, gas exchange occurs with the oxygen-containing gas introduced from the gas inlet 19 and flowing inside the hollow fiber membrane, and oxygen is added to the blood. Carbon dioxide gas is removed, and the removed carbon dioxide gas is discharged from the gas outlet 20.

As described above, according to the present invention, blood is smoothly introduced into the annular chamber 15 formed between the outer cylinder 14 and the inner cylinder 12 from the annular surface liquid sending passage 13, and a part of the blood is In order to flow into the hollow fiber annular bundle 11 and the other part into the gap 16 formed between the inner cylinder 12 and the hollow fiber annular bundle 11, the blood flow direction is sharply bent or narrowed. It is possible to reduce pressure loss without causing damage.

Furthermore, after the blood flows radially within the hollow fiber annular bundle 11 to perform gas exchange, the blood flows through the hollow fiber annular bundle 11 at the peripheral edge near the upper end of the outer tube 14 on the opposite side from the end of the annular surface liquid delivery passage 13. Since the blood flows through the annular blood passage 17, the blood flows evenly and evenly, and uneven blood flow can be prevented.

Next, a method for bundling and distributing hollow fiber membranes will be explained.

First, a hollow fiber bundle made of hollow fiber membranes is once focused and distributed into a cylinder (a focusing cylinder) having a diameter larger than that of the inner cylinder 12.

After the bundle and distribution, the hollow fiber (fiber) annular bundle 11 is inserted into the space between the outer cylinder 14 and the inner cylinder 12 to separate the inner cylinder 12 and the hollow fiber annular bundle 1.
By providing a predetermined gap between the hollow fiber membranes 1 and 1, the hollow fiber membranes of the oxygenator of the present invention can be bundled and arranged.

The diameter of the focusing tube only needs to be larger than the inner tube 12 of the artificial M, and it is usually preferable that the difference in diameter between the focusing tube and the inner tube 12 is 2■■ or more, more preferably in the range of 4 to 10 m layer. It is.

In addition, after the focusing and yarn distribution, it is necessary to transfer the hollow fiber annular bundle 11 from the focusing tube to the annular chamber (space) 15 between the outer tube 14 and the inner tube 12 of the oxygenator. In order to be able to move smoothly without damaging the hollow fiber annular bundle 11,
It is preferable that the surface of the focusing tube is subjected to a surface smoothing treatment using a fluororesin or the like. Alternatively, the focusing cylinder may have a structure in which the diameter can be changed.

In addition, when converging and distributing the hollow fiber annular bundle 11 to the converging tube, if the tension of the hollow fiber membrane at the time of convergence is too large, or the hollow fiber membrane does not move on the converging tube surface, or even if it can move, the hollow fiber membrane Since there is a risk of damage, the tension applied to the hollow fiber membrane is usually 10 g or more, preferably 30 to 170 g. The tension applied to the hollow fiber membrane can be adjusted, and by changing the tension toward the outside of the hollow fiber annular bundle, a high filling rate of the hollow fiber membrane can be obtained, and uneven flow of blood can be prevented and high gas It is preferable because exchangeability can be achieved.

In order to pursue a blood flow type in an oxygenator that improves the gas exchange capacity, the present inventor investigated various methods of arranging (wrapping) hollow fiber membranes, and found that It has been found that when the ratio is constant, the winding of the hollow fiber membrane with respect to the pitcher's force direction of the outer cylinder increases the gas exchange ability when the edge angle θ is within a certain range. That is, the hollow fiber ridge angle θ of the artificial lung is preferably greater than or equal to ioo" and less than 130". If the hollow fiber edge angle O is less than 100°, blood tends to flow along the hollow fiber membrane, and a sufficient turbulence effect cannot be obtained, resulting in a decrease in gas exchange performance, which is undesirable.
If the angle is greater than 0°, blood stagnation tends to occur, leading to thrombus formation, which is undesirable.

Furthermore, the filling rate of the hollow fiber membrane is made densest near the inner cylinder 12,
By arranging the fibers so that they become sparser toward the outside, the hollow fiber bundle itself acts as a resistance to the flow of blood near the blood inlet, allowing blood to spread evenly to the outside of the hollow fiber bundle. This is preferable because it prevents blood channeling and becomes an OT moat.

Furthermore, as the material for the hollow fiber membrane, polyolefin resins such as polypropylene and polyethylene, fluorine resins such as polyvinylidene fluoride and ethylenetetrafluoroethylene copolymer, or hydrophobic resins such as silicone resins are preferably used. Furthermore, even if a material other than a hydrophobic resin is used, it is also possible to use a material whose contact surface with blood is treated with silicone resin or the like to make it hydrophobic. Any hollow fiber membrane can be used as long as it is gas permeable, and it does not matter whether it has a large number of micropores in its peripheral wall or is non-porous. Note 1: For example, in the case of a membrane having micropores, the average pore diameter of the micropores is generally preferably o, oi to 1 μm.Furthermore, the porosity of the hollow fiber membrane is generally about 20 to 80%. The filling factor of the hollow fiber membrane is preferably 0.5 to 0.0 in the vicinity of the inner cylinder 12.
65 is preferable, and the range of 0.55 to 0.6 is more preferable. If the filling rate is less than O or S, it will not function as a resistance to blood, and the blood flowing out from the inner cylinder 12 will immediately flow into the outer cylinder 1.
4, the blood flows directly near the outer cylinder 14 and reaches the outlet, so the blood does not spread throughout the hollow fiber bundle, making it impossible to obtain good gas exchange performance, which is undesirable, and if the filling rate exceeds 0.65. Since the resistance to blood flow increases, the pressure loss increases, which is undesirable.On the other hand, in the vicinity of the outer cylinder 14, the range is preferably 0.40 to 0.55, and more preferably 0.45 to 0.50. be. Filling rate is 0.40
If it is less than this, blood channeling tends to occur and the amount of blood becomes large, which is not preferable. Furthermore, if the filling rate exceeds 0.55, the pressure loss will increase, which will affect blood cells, which is not preferable.

Here, the filling rate of the hollow fiber membrane refers to the ratio of the volume occupied only by the hollow fiber membrane to the total volume of the portion occupied by the hollow fiber bundle.

[Examples] The present invention will be further described below based on illustrated examples, but the present invention is not limited to these examples.

FIG. 1 is a cross-sectional configuration diagram showing an embodiment of the present invention.

The oxygenator of this example has gas exchange #! It consists of a heat exchanger section (1) and a heat exchanger section (2) that is integrally disposed below the heat exchanger section (H), and a carbon dioxide gas cartridge is provided inside the heat exchanger section (H).

In the gas exchanger section I, in the annular chamber 15 between the outer cylinder 14 and the inner cylinder 12, there is a cylindrical chamber formed by concentrating one or more gas-permeable hollow fiber membranes in a cross-wound manner. A hollow fiber annular bundle 11 is housed and arranged.

At both ends of the outer cylinder 14 and the inner cylinder 12, partition walls are provided so that both ends of the outer cylinder 14 and one end of the inner cylinder 12 are closed so that both ends of the hollow fiber membrane forming the hollow fiber annular bundle 11 are open. One of the partition walls, the first partition wall 21, closes the ends of both the outer cylinder 14 and the inner cylinder 14, and the other partition wall, the second partition wall 22, closes the end of the outer cylinder 14. The end portion of the inner cylinder 12 is formed so as to be closed or not to be closed.

A first cap 23 having an inlet 19 for oxygen-containing gas communicating with the hollow fiber membrane internal space is attached to the first partition wall 21, while a first cap 23 having an oxygen-containing gas inlet 19 communicating with the hollow fiber membrane internal space is attached to the second partition wall 22. A second cap 24 is crowned with an outlet 20 for oxygen-containing gas communicating therewith. Further, the second partition wall 22 is provided with an annular liquid delivery passage 13 that communicates with the annular chamber 15 of the outer cylinder 14 and is independent of the second cap 24 in a fluid-tight manner.

Furthermore, the peripheral edge near the L end of the outer cylinder 14 is provided with blood [1].
A blood annular passage 17 is provided which communicates with 18.

The outer periphery of the outer tube 14 is covered with a decorative tube 25 with a space therebetween.

On the other hand, the heat exchanger section (2) is integrally arranged at the lower part of the gas exchanger section I, and inside the outer house shifter 26 of the heat exchanger section H is a heat exchanger for maintaining blood at a predetermined temperature. A heat exchanger 27 made of a tube is provided.

This heat exchanger 27 is constructed by spirally winding a heat exchange tube with a double-tube structure, and in this example, an inner tube 28
A water flow path 29 is used for water to flow through the inside of the tube, and a blood flow path 31 is used for blood to flow between the inner tube 28 and the outer tube 30.

Then, a carbon dioxide gas cartridge 32 is loaded into the internal space of the heat exchanger 27 of the heat exchanger section (2), and the carbon dioxide gas from the carbon dioxide cartridge 32 passes through the tube 37 to the carbon dioxide gas inlet 38 provided in the second cap 24. It is used for priming.

In addition, blood collection boats 33, 34 and temperature measurement boats 35, 36 are provided near the blood population 10 and blood outlet 18, respectively.
Or is provided.

In the above configuration, blood passes through the blood inlet lO, is introduced into the blood flow path 31 of the heat exchanger 27, and is heated to a predetermined temperature by exchanging heat with the water flowing through the water flow path 29. . Next, blood is introduced into the annular chamber 15 from the annular blood feeding passage 13, and part of the blood enters the annular hollow fiber bundle 11, and the other part is formed between the inner tube 12 and the annular hollow fiber bundle 11. The liquid flows into the gap 16 where the liquid is formed. Thereafter, the blood gradually spreads throughout the hollow fiber annular bundle 11, flows outside the hollow fiber membrane within the hollow fiber annular bundle 11, and flows through the blood annular passage 17 provided at the periphery near the upper end of the outer cylinder 14. After reaching the blood outlet 18
more excreted.

As described above, while the blood flows through the entire hollow fiber annular bundle 11, gas exchange occurs with the oxygen-containing gas introduced from the gas inlet 19 and flowing inside the hollow fiber membrane, and oxygen is added to the blood. At the same time, carbon dioxide gas is removed.

Next, specific implementation results will be explained.

(Example 1) A focusing cylinder having an outer diameter of 30 mm and having a surface coated with a fluororesin was prepared, and a hollow fiber membrane was focused.

After convergence, the hollow fiber annular bundle was moved onto the concentrating tube and extracted, and at the same time, the hollow fiber bundle was inserted between the inner tube and the outer tube to produce an oxygenator having the following dimensions and the configuration shown in FIG. 1. The tension of the hollow fiber membrane when converging is 100 g in the first half and 150 g in the second half.
It was set as g.

Focusing tube 2 length -350-■ Outer diameter...φ30-Bottom surface...Fluorine resin coating Outer tube inner diameter (outer casing)...φ5Bms Inner tube (inner core) outer diameter...φ25m Porous hollow fiber membrane inner diameter...
・Approx. 300 gm Outer diameter: approx. 400 mm Average pore diameter: 0.22 s Porosity: 65-70% Material: Polypropylene hollow fiber bundle: twill winding, angle 0 = 130' Effective length of the hollow fiber annular east: 180 m1 Supporting member: Gap between the outer surface of the polyurethane resin inner cylinder and the inner surface of the hollow fiber bundle: 2.5 i*m on one side (5 I1 rin in total) of the annular blood feeding passage Inner diameter: 21mm Slit width of the circular blood sending passageway: 8mm Blood circular passageway: An artificial body with a configuration and specifications that are greater than or equal to the ring-shaped passageway with an inner diameter of 58cm and a cross-sectional area of 4 x loam. A sex fl test was performed using lungs and fresh blood. AAM 1 as fresh blood (^5so
cation for the Advance o
f Medical In5tru+5entatio
After the standard venous blood specified in item (n) was prepared, it was introduced into the oxygenator.

For gas exchange capacity test, blood flow rate 1fL/m103
This was done for M/win and 5 sentences/■in.

In addition, regarding pressure loss, blood flow is 1/Kamaguchi, 3/1
This was done for 0 and 517 sins. Blood sampling and pressure measurements were performed near the blood inlet and blood outlet of the artificial lung. After obtaining the oxygen partial pressure, saturation degree, carbon dioxide partial pressure, CO□ amount, PH, etc. of the collected blood using a gas analyzer, the amount of oxygen transfer and the amount of carbon dioxide transfer were calculated. Oxygen gas was blown into the oxygenator in such a manner that the ratio of blood flow rate and convection flow j and S was adjusted to be 1:l.

The results are shown in FIGS. 2, 3 and 4.

As is clear from these results, in this artificial lung, a high amount of oxygen transfer and a high amount of carbon dioxide gas transfer were obtained while the pressure loss was not so high, indicating that the gas exchange performance was good.

[Effects of the Invention] As stated in Theory IJ1, according to the hollow fiber membrane oxygenator of the present invention, the blood flow direction is not sharply bent or narrowed, so that the pressure loss is reduced. This makes it possible to reduce the amount of blood filled, which allows the device to be made smaller. Furthermore, in the hollow fiber membrane oxygenator of the present invention,
Blood flows radially within the hollow fiber annular bundle and flows into the blood annular passage after gas exchange, which has the advantage that the blood flows evenly and uniformly and that uneven blood flow can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional diagram showing an embodiment of the present invention, Fig. 2 is a graph showing the amount of oxygen transferred, Fig. 3 is a graph showing the amount of carbon dioxide transferred, and Fig. 4 shows the pressure loss of the oxygenator. It is a graph. 10-・Blood inlet, ll-・Hollow fiber (fiber) annular bundle 1
2... Inner tube (inner core), 13... Blood annular feeding passage, 14... Outer tube, 15... Annular chamber, 16... Gap, 17... Blood annular passage, 18 ...Blood outlet, 1
9... Gas inlet, 20... Gas outlet, 21... First partition, 22... Second partition, 23-... First cap, 24-... Second cap, 25...・・Cosmetic tube, 2
6...Outer housing, 27...Heat exchanger, 28.
...Inner pipe, 29 River water flow path 30...Outer pipe, 31...Blood flow path, 32-...Carbon dioxide gas cartridge, 33.34
... Blood collection boat, 35° 36 ... Temperature measurement boat, 37
...Tube, 38...Carbon dioxide gas inlet.

Claims (1)

[Claims] (1) A cylindrical hollow fiber annular bundle formed by converging and distributing one or more gas permeable hollow fiber membranes having a space in the center in a twill shape is housed in an outer cylinder, and Insert an inner cylinder having a diameter smaller than the diameter of the cylindrical space into the cylindrical space inside the hollow fiber annular bundle, and insert the hollow fiber annular bundle into the cylindrical space at both ends of the outer cylinder so that both ends of the hollow fiber membranes are open. The inner cylinder is supported by a partition wall so as to close one end thereof, and the first partition wall that blocks the ends of both the outer cylinder and the inner cylinder has a first partition wall that has an inlet or an outlet for oxygen-containing gas that communicates with the inner space of the hollow fiber membrane. A second cap is attached to the first cap, and the second partition wall has an inlet or an outlet for oxygen-containing gas communicating with the inner space of the hollow fiber membrane, and the end of the outer cylinder is closed, but the end of the inner cylinder is not closed. and an annular blood feeding passage communicating with the inner space of the outer cylinder and independent of the second cap in a fluid-tight manner, and communicating with a blood outlet at the peripheral edge near the upper end of the outer cylinder. A hollow fiber membrane oxygenator characterized by having a blood annular passage.