JPH03158167A - Artificial lung - Google Patents

Abstract

PURPOSE:To improve gas exchange ability, to suppress the occurrence of channelling and to reduce incurring of a pressure loss by a method wherein first fluid is caused to flow through a hollow fiber and second fluid is caused to flow in a direction extending substantially at right angles with the axial direction of a hollow fiber in a reticulate membrane member. CONSTITUTION:Since gaps enough for the flow of blood in the direction of an axis X-Y through meshes of a reticulate membrane member 3 are provided, blood flowing in a blood inflow chamber 11 flows through the reticulate membrane member 3 in a direction extending substantially at right angles with each hollow fiber 4. Since blood flows through a gap between the warp and weft of the hollow fiber in a direction extending at right angles with the hollow fiber, the blood is brought into a turbulent flow state in the vicinity of the hollow fiber and therefore, excellent gas exchange ability is provided. This constitution suppresses the occurrence of channelling without the increase of the number of the hollow fibers and the increase of the effective length thereof, reduces incurring of a pressure loss, and reduces the size of an artificial lung.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an artificial lung that uses hollow fibers to add oxygen to blood and remove carbon dioxide gas.

[Prior Art] As this type of artificial lung, there are conventional artificial lungs as shown below.

For example, a hollow fiber bundle made up of a plurality of hollow fibers is placed inside a housing, and a partition wall is provided at the end of the hollow fiber bundle with the ends of the hollow fibers open. The end of the hollow fiber bundle is fixed at the end, and blood flows as a first fluid inside each hollow fiber, and oxygen-containing gas flows as a second fluid outside the hollow fiber. Perfusion type oxygenators are known.

Furthermore, a so-called external casing flow type oxygenator is also known, in which oxygen-containing gas is allowed to flow inside the hollow fibers, and blood is allowed to flow outside the hollow fibers.

In any of these artificial lungs, mass transfer occurs through gas exchange between carbon dioxide gas in the blood and oxygen in the oxygen-containing gas through the membrane wall of the hollow fiber.

[Problems to be Solved by the Invention] By the way, in the above-mentioned conventional oxygenator, since both processing fluids flow in parallel inside and outside the hollow fibers and in opposing states along the axial direction of the hollow fibers, Laminar flow occurs, and gas exchange between the blood and oxygen-containing gases is not effective.
There was a problem that sufficient gas exchange capacity could not be obtained.

In order to solve this problem, it is necessary to increase the effective membrane area by increasing the number of hollow fibers or by increasing their effective length. As a result, it becomes increasingly difficult for the fluid flowing outside the hollow fiber membrane to reach the inside of the hollow fiber bundle, and there is a risk that so-called channeling, in which the fluid flows biased toward the peripheral surface, may occur. That is not enough.

In addition, when increasing the effective length, with internal perfusion type fibers, it is necessary to apply a certain pressure to circulate blood inside the hollow fiber, so the pressure loss is reduced by the length. This was also a problem because it could become large and cause harmful effects on the blood.

On the other hand, with the external perfusion type, there is no need to install a pump upstream of the oxygenator, and circulation is possible by using only the head.
Although the above-mentioned problem of pressure loss is small, the longer effective length makes the oxygenator larger and the amount of blood flowing outside the body increases accordingly (therefore, the priming volume increases).

The present invention has been made in view of such problems, and an object of the present invention is to change the direction of the second fluid flowing outside the hollow fiber with respect to the direction of the first fluid flowing inside the hollow fiber. The hollow fibers are configured to be substantially orthogonal to the axial direction of the hollow fibers, thereby eliminating the laminar flow state of the second fluid and without increasing the number of hollow fibers or lengthening their effective length.
An object of the present invention is to provide an artificial lung that can improve gas exchange ability, suppress channeling, reduce pressure loss, and further reduce priming volume.

[Means for Solving the Problems 1] In order to achieve the above object of the present invention, in the present invention, a plurality of fluids are used to perform mutual mass transfer between the first and second fluids via the membrane wall of the hollow fiber. A mesh-like membrane member formed by combining hollow fibers vertically and horizontally and stacking them, the first fluid flowing inside the hollow fibers, substantially in the axial direction of the hollow fibers in the mesh-like membrane member. The present invention proposes an artificial lung characterized by a configuration in which the second fluid is caused to flow in a direction perpendicular to .

The artificial lung according to the present invention includes a housing having a first fluid inlet and an outlet, a second fluid inlet and an outlet, and a housing fixed to the housing and the mesh-shaped and a partition wall provided on the side surface of the mesh-like membrane member that opens each hollow fiber end in the membrane member,
The first fluid flowing in from the first fluid inlet flows through the hollow fibers opened in the partition wall portion and communicates with the first fluid outlet in a fluid-tight manner. The second fluid flowing in from the inflow port passes from the corresponding one mesh opening end of the mesh-like membrane member to the other mesh opening end,
It is proposed that the mesh-like membrane member flows through the mesh openings and is in fluid-tight communication with the second fluid outlet.

Further, in the mesh-like membrane member in the oxygenator according to the present invention, the partition wall is provided on each side surface, and a pair of mutually adjacent side surfaces faces the inlet for the first fluid, and the other side surface is adjacent to each other. a pair of side surfaces are the first
A structure in which the fibers face the fluid outlet, or a structure in which hollow fibers or hollow fibers and solid fibers are woven or knitted together have been proposed.

Furthermore, as a specific configuration of the mesh-like membrane member, the hollow fibers forming one of the warp and weft threads of the mesh-like membrane member are formed of a porous membrane for gas exchange, and the hollow fibers forming the other thread are formed of a porous membrane for gas exchange. A configuration in which a non-porous membrane for heat exchange is used, a configuration in which the mesh pitch of the mesh-shaped membrane member is varied along the layer direction of the mesh-shaped membrane member, and a configuration in which the mesh of the mesh-shaped membrane member is A configuration in which the eye position is shifted laterally with respect to the layer direction has been proposed.

Further, the first fluid may be an oxygen-containing gas and the second fluid may be blood, or conversely, the first fluid may be blood and the second fluid may be an oxygen-containing gas. The composition is proposed.

[Function 1] In the oxygenator according to the present invention having the above configuration, a mesh-like membrane member is provided in which a plurality of hollow fibers are combined vertically and horizontally and laminated, and a first fluid flows inside the hollow fibers, and a second fluid flows inside the hollow fibers.
The fluid is applied to the mesh in a direction substantially perpendicular to the axial direction of the hollow fibers in the mesh-like membrane member, for example, from one mesh opening end of the mesh-like membrane member to the other mesh opening end. The first fluid flows through the hollow fibers, and gas exchange is performed in a manner perpendicular to the first fluid flowing within each hollow fiber.

Therefore, the fluid flowing through the eyes of the mesh passes through the gaps between the hollow fibers in a direction perpendicular to each other. 5 If the second fluid is blood, for example, the blood becomes turbulent, which improves gas exchange. Therefore, there is no need to increase the number of hollow fibers or increase their effective length (channeling can be suppressed, pressure loss can be reduced, and the size of the oxygenator can be made smaller. , the priming volume can be reduced.

[Example] An example of the artificial lung of the present invention will be described based on FIGS. 1 to 6.

In the figure, l is a box-shaped oxygenator housing, 1
a is a bulge formed integrally with the housing.

As shown in FIG. 4, the bulging portion 1a has an elliptical shape in cross section. Reference numeral 3 denotes a mesh-like membrane member, which forms a rectangular block and is supported at the center within the housing l.

The mesh-like membrane member 3 is formed by combining a large number of hollow fibers 4 vertically and horizontally and forming layers. The combination of the hollow fibers 4 includes a configuration in which the warp and weft of the hollow fibers are woven or knitted in a hand-woven manner and stacked in multiple layers.
Alternatively, various configurations can be considered, such as a configuration in which layers of parallel hollow fibers are alternately laminated at orthogonal angles to form a mesh-like structure.

The mesh-like membrane member 3 layered in this way has one (lower) opening end 3a of the mesh and the other (upper) opening end 3b of the mesh.
Until then, between the eyes of the mesh formed by the hollow fiber 4,
A second fluid is allowed to flow along the axis line X--X of the mesh-like membrane member.

Frame-shaped partition walls 6 are provided on four side surfaces of the mesh-like membrane member 3.

The partition wall 6 is made of polyurethane, for example, and is obtained by dipping one side of the polyurethane. At this time, the ends of the hollow fibers 4 are sealed with the same material as the partition walls 6 and then dipped, and after the partition walls 6 have hardened, the outer periphery thereof is sliced with an appropriate cutting tool. As a result, the ends of the hollow fibers 4 are maintained in an open state.

As shown in FIG. 5, this partition wall 6 is attached to the inner peripheral edge of the housing 1 and its bulging portion 1a, and thereby the mesh-like membrane member 3 is installed within the housing 1.

As shown in FIG. 4, in the set state, the partition wall 6a on one pair of adjacent side surfaces 3c and 3d and the partition wall 6b on the other pair of side surfaces 3e and 3f are fitted into the housing 1. The corner portion 3g of the mesh-like membrane member 3 is airtightly partitioned.

Each hollow fiber 4 has an oxygen-containing gas constituting the first fluid flowing through the inside thereof, and blood constituting the second fluid flowing through the outside thereof, and between the two fluids through the membrane wall of the hollow fiber 4. The oxygenator in this embodiment is of an external perfusion type.

As shown in FIG. 4, the inside of the housing 1 includes an oxygen-containing gas inflow chamber 8 communicating with the gas inflow lower, and a gas outlet 9.
The gas outlet chambers 10 and 10 are respectively separated from each other. Then, the oxygen-containing gas enters the gas inflow lower and gas inflow chamber 8 as shown by arrow A, and from there enters each hollow fiber 4 opened at the partition wall 6a of the mesh-like membrane member 3, and flows along the axis X- The gas enters the gas outflow chamber 10 from the other partition wall 6b along the axial direction of each hollow fiber orthogonal to X, and is led out from the gas outflow port 9.

On the other hand, a blood inflow chamber 11 and a blood outflow chamber 12 are formed between the opening ends 3a, 3b of the mesh-like membrane member 3 and the inner wall of the housing l, respectively, and the blood flows in a corresponding manner to each chamber. A blood inlet 13 communicating with the inflow chamber 11. A blood outlet 14 communicating with the blood outflow chamber 12 is provided, respectively. Then, the blood enters the inflow chamber 11 from the blood inlet 13 as shown by arrow B in FIG. 12 and is led out from the blood outlet 14.

According to the above configuration, a sufficient gap is formed in the direction of the axis X-x through the mesh of the mesh-like membrane member 3, so that the blood flowing into the blood inflow chamber 11 flows through the mesh. It flows through the membrane member 3 in a direction substantially perpendicular to each hollow fiber 4 . Since the blood passes through the gaps between the warp and weft of the hollow fibers 4 in a direction perpendicular to the hollow fibers, a turbulent flow occurs near the hollow fibers.
Here, excellent gas exchange ability can be exhibited.

Therefore, without increasing the number of hollow fibers or lengthening their effective length, channeling can be suppressed, pressure loss can be reduced, the oxygenator can be made smaller, and brimming polyneme can be reduced. be able to.

In the above embodiment, for the hollow fibers 4 of the mesh-like membrane member 3, if a hydrophobic hollow fiber membrane made of, for example, polypropylene is used as the warp, and a hollow fiber membrane or solid fiber imparted with hydrophilicity is used as the weft, Briming becomes easier.

Further, among the hollow fibers 4 constituting the mesh-like membrane member 3, for example, if the warp threads are formed of a porous membrane for gas exchange and the weft threads are formed of a non-porous membrane for heat exchange, gas exchange and heat exchange can be performed. Since it can be done all at once, the effect of reducing the priming polyneme is further improved.

Furthermore, the pitch of the mesh of the mesh-like membrane member 3 is varied along the direction of the laminated layers, for example, the pitch is 1. O
A configuration in which layers of n+m and layers of 0.7+mm are alternately laminated is also considered. Alternatively, it is also possible to consider a structure in which the meshes are laminated with their meshes deviated in the lateral direction, such as a structure in which the axial angles of the hollow fibers are shifted little by little, or a structure in which the meshes are stacked while being shifted in parallel to the lateral direction.

With the various configurations described above, a favorable turbulent flow effect can be obtained, and the gas exchange performance can be further improved.

Although the present invention has been described above with reference to Examples, the present invention is not limited to the above-mentioned Examples, and can be modified in various ways without changing the gist of the present invention.

For example, in the above embodiment, an external perfusion type oxygenator was described, but an internal perfusion type oxygenator is of course also applicable. of the blood, and can prevent excessive pressure that may be harmful to the blood.

Next, the inventor conducted the following experiment to confirm the effects of the above embodiment.

(Experimental Example) First, an oxygenator having the same configuration as in the above example was prepared. Here, the hollow fiber 4 is a porous hollow fiber made of polypropylene with a membrane thickness of 50 μm, and this is woven in a plain weave to form the mesh of each layer of the mesh-like membrane member, the pitch of this mesh is 1 mm, and the number of laminated sheets is 186 sheets, the effective membrane area is 0.4 m'', and the effective length β is 30 mm as shown in Figure 4.
, the filling rate is 40%, and the mesh-like membrane member 3 shown in FIG.
The height h of the partition wall 6 shown in FIG. 4 is 94.3 mm, the thickness t of the partition wall 6 is 15 mm, the material thereof is polyurethane,
The material is made of polycarbonate.

Note that the filling rate refers to the proportion of hollow fibers (including the internal space of the hollow fibers) per unit volume.

Next, the artificial lung 13 was placed in the experimental circuit shown in FIG. This experimental circuit includes tanks 14 and 14 provided on the upstream and downstream sides of the oxygenator 13, and a tank 1 on the upstream side.
Blood is pumped into the oxygenator 13 along the arrow B by a roller pump 15 located between the oxygenator 4 and the oxygenator 13.

Heparinized blood was used as the blood, and its hematocrit value Ht was 35.1%, and the blood temperature was 37°C.

Oxygen-containing gas is sent into the artificial lung 13 along arrow A. Each position 1 on the upstream side and downstream side close to the oxygenator 13
Sampling was performed at 6.17, and blood flow, gas flow rate, and oxygen saturation were measured twice for the same sample. The results are shown in Table 1.

Table 1 As is clear from the results in Table 1 above, a sufficient oxygen addition ability was obtained.

[Effects of the Invention] As explained above, according to the oxygenator according to the present invention, the mesh of the mesh-like membrane member formed by combining hollow fibers vertically and horizontally and laminating them can be connected from one open end to the other. Since the second fluid is allowed to flow in a direction substantially perpendicular to the axial direction of each hollow fiber through the mesh holes toward the open end, excellent gas flow between the first fluid and the first fluid flowing inside the hollow fibers is achieved. This enables, for example, to suppress channeling and reduce pressure loss without increasing the number of hollow fibers or lengthening their effective length. It has various effects such as being able to reduce the priming volume.

[Brief explanation of the drawing]

FIG. 1 is an external front view showing an embodiment of the artificial lung of the present invention;
Fig. 2 is a side view of Fig. 1, Fig. 3 is a plan view of Fig. 1, Fig. 4 is a cross-sectional section taken along line 4-4 in Fig. 1, and Fig. 5 is a sectional view of Fig. 3.
The longitudinal sectional view taken along line -5 and FIG. 6 is an experimental circuit.

Claims (9)

[Claims] (1) A mesh-like membrane member formed by combining a plurality of hollow fibers vertically and horizontally and stacking them in order to perform mutual mass transfer between the first and second fluids through the membrane wall of the hollow fibers, An artificial lung characterized in that the first fluid is caused to flow inside the fibers, and the second fluid is caused to flow in a direction substantially perpendicular to the axial direction of the hollow fibers in the mesh membrane member. (2) A housing having a first fluid inlet and an outlet and a second fluid inlet and an outlet, and each hollow fiber end portion in the mesh membrane member that is fixed to the housing. a partition wall provided on a side surface of the mesh-like membrane member that opens the first fluid, and the first fluid flowing in from the first fluid inlet flows through the hollow fibers opened in the partition wall portion, and in fluid-tight communication with the fluid outlet;
The second fluid flowing in from the second fluid inlet flows from the corresponding one mesh opening end of the mesh membrane member to the other mesh opening end through the mesh openings of the mesh membrane member. 2. The oxygenator according to claim 1, which is in fluid-tight communication with the second fluid outlet. (3) The mesh-like membrane member is provided with the partition walls on each side, and a pair of adjacent side surfaces are connected to the first side.
3. The oxygenator according to claim 2, wherein a pair of side surfaces facing the fluid inlet and the other adjacent to each other face the first fluid outlet. (4) The mesh membrane member is formed by weaving or knitting hollow fibers or hollow fibers and solid fibers together. artificial lung. (5) The hollow fibers forming one of the warp and weft threads of the mesh membrane member are formed from a porous membrane for gas exchange, and the hollow fiber forming the other thread is formed from a non-porous membrane for heat exchange. The artificial lung according to any one of claims 1 to 3. (6) The oxygenator according to any one of claims 1 to 3, wherein the mesh pitch of the mesh membrane member is varied along the layer direction of the mesh membrane member. (7) The artificial lung according to any one of claims 1 to 3, wherein the mesh position of the mesh of the mesh-like membrane member is offset in the lateral direction with respect to the layer direction. (8) The first fluid is an oxygen-containing gas, and the second fluid is an oxygen-containing gas.
8. The artificial lung according to claim 1, wherein the fluid is blood. (9) The artificial lung according to any one of claims 1 to 7, wherein the first fluid is blood and the second fluid is an oxygen-containing gas.