JPS6187566A - Hollow yarn membrane type artificial lung having heat exchanger mounted therein - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hollow fiber membrane type oxygenator having a built-in heat exchanger.

[Conventional technology]

As an artificial lung using a hollow fiber membrane, for example, US Pat.
Various proposals are already known, such as JP-A No. 744468, JP-A-54-160098, and JP-A-58-155862.

These methods use microporous hollow fiber membranes made of hydrophobic polymers such as polyolefins or gas-permeable homogeneous middle-wall fiber membranes such as silicone to bring gas and blood into contact through the hollow fiber membrane surface. There is a system in which gas is exchanged between the two, with blood flowing into the inner part of the hollow fiber membrane and gas flowing outside the hollow fiber membrane, and vice versa, gas flowing into the middle part of the hollow fiber membrane. There are two methods: one in which blood flows externally, and the other in which blood flows externally.

Most conventional artificial lungs simply consist of a bundle of gas exchange hollow fiber membranes packed in a single cylindrical housing parallel to the axis of the cylindrical housing. In either of the above two methods, the gas exchange capacity per unit area of the hollow fiber membrane is low. As an improved version of the latter method, a hollow fiber membrane is wrapped around a cylindrical shaft of a hollow nitrogen core having many perforations on the wall, and this is housed in a housing, and blood flows out from the hollow part of the cylindrical shaft through the perforations. US Pat. No. 3,794,468 proposes an oxygenator in which the gas is allowed to flow through the hollow part of a hollow fiber membrane.

In addition, when blood that has been gas exchanged using an artificial lung is returned to the patient's body from an extracorporeal gas exchange circuit, the temperature of the blood needs to be approximately equal to the patient's body temperature. For this purpose, a heat exchanger made of a metal with good thermal conductivity such as stainless steel as a heat transfer member has been attached to the blood gas exchange circuit in an artificial lung.

[Problem that the invention seeks to solve]

In the internal perfusion method, blood is poured into the hollow part of the hollow fiber membrane and gas is exchanged by flowing the gas outside the hollow fiber membrane. In this method, the blood is evenly distributed and supplied to a large number of hollow fiber membranes. Although there is no polarized flow, the blood flowing through the inner part of the hollow fiber membrane becomes a laminar flow, so in order to increase the oxygen uptake capacity (oxygen transfer rate per unit membrane area), the inner diameter of the hollow fiber membrane must be made small. It is necessary to do this, and for this purpose 150 to 30
Hollow fiber membranes having an inner diameter of about 0 μm have been developed for use in oxygenators.

However, even if the diameter is made thinner, as long as the blood flows laminarly, the oxygen uptake capacity will not improve significantly. ) occurs frequently (7), which is a large gap in practical use.Also, in general, in an oxygenator, tens of thousands of hollow fiber membranes are used as a bundle, and these large numbers of hollow fiber membranes are Special consideration is required to supply gas diffusely to each membrane. If the distributed supply of gas is non-luminous, the carbon dioxide excretion capacity (carbon dioxide transfer per unit membrane area) must be taken into account. speed) decreases.

On the other hand, in the external laminar flow method in which the inside part of the hollow fiber membrane is contaminated and the blood layer flows outside, gas distribution is not good.
Although turbulence can be expected to occur in the flow of blood, there is a problem that blood channeling may lead to insufficient oxygenation or clots in the stagnation area. The artificial lung of this issue also had problems, such as an excessive amount of blood filling and the complicated manufacturing process. do not have.

1. Adjustment of the blood gas exchange circuit was generally carried out in treatment facilities such as hospitals by connecting an oxygenator and a heat exchanger via a circuit tube or the like. Therefore, for the user, blood gas VP! Assembling the circuit is complicated and there is a risk of assembling the circuit incorrectly! !
: Another problem was that it required space to install the circuit. Furthermore, since it has an artificial lung and a heat exchanger, which are separate blood storage parts, and a circuit connection tube is required to connect them, the amount of blood required at the initial stage of circuit operation is large. It is necessary to remove bubbles from these constituent members separately, and the operation is also complicated.

As a means to solve such problems, an example is the
No. 5-2982, Japanese Unexamined Patent Publication No. 57-39854, etc. disclose an artificial lung device in which an artificial lung and a heat exchanger are integrated. However, these artificial lung devices have not always been satisfactory in terms of blood gas exchange performance or the size of the artificial lung device.

[Means to solve the problem]

The present invention has been made to solve all of these problems, and is an artificial lung that has excellent oxygen uptake ability and carbon dioxide excretion ability, and hardly causes blood stagnation or channeling. and a heat exchanger that is small and lightweight and has an excellent heat exchange function, to provide an oxygenator that is compact and easy to use for users with a cheap and simple structure that does not require complicated manufacturing. It is something.

That is, the gist of the present invention is to have a blood inlet, a blood outlet, a gas inlet and a gas outlet, a heat exchange medium outlet and a heat exchange medium outlet, and have a generally shallow box shape as a whole, and A first hollow fiber bundle consisting of a large number of gas exchange hollow fibers with both ends fixed, and a first hollow fiber bundle consisting of a large number of heat exchange hollow fibers with both ends completely fixed, which has a contact chamber inside. The contact chamber is divided into a blood flow path whose width is narrowed by a baffle plate and a plurality of small chambers 7' (the first and second hollow fiber bundles are separated from each other via the blood flow path) The two hollow fiber bundles are in a hollow fiber membrane oxygenator that includes a heat exchanger installed in separate small chambers in parallel with the baffle plates.

Hereinafter, the oxygenator of the present invention will be explained in detail using the drawings.

FIG. 1 is a partially cut away vertical sectional view showing an example of an embodiment of the artificial lung of the present invention, and FIG. 2 is a partially cut away plan view.

The oxygenator of the present invention has a gas exchange function section (1) consisting of a small chamber in which a first hollow fiber bundle (8) that performs a blood gas exchange function is installed, and a gas exchange function section (1) that does not require a tube or the like to be connected thereto (face-to-face connection). It is also composed of a gas exchange function section (2) consisting of a small chamber in which a second inner yarn bundle is installed which performs a blood heat exchange function.

Gas exchange function part (1) K is basically a hollow fiber membrane (3
) and a botting material (4) are built in. These members allow oxygen to flow between the contact chamber (5) through which blood flows and the interior of the hollow fiber membrane (3). divided into a gas distribution path (6) for supplying a gas containing
,ing. The inside of the contact chamber (5) is installed in a direction transverse to the blood flowing direction and has a width in a direction perpendicular to the installation direction of the inner membrane (hereinafter referred to as the thickness direction of the contact chamber). A blood flow path (7) configured to divide the blood flow path, and a hollow fiber membrane (3) separated through the blood flow path (7) and inside the blood flow path (7).
The entire building is divided into several small rooms. Blood flow path (7
) is provided with struts (
9) may be provided. The gas exchange function part (1) having a shallow box shape has a gas inlet (10), a gas outlet (11), a blood inlet (12), and a trough fluid inlet/outlet of the blood flow path (7). It has an anus.

The hollow fiber membrane (3) passes through the small chamber almost linearly, and by means of two opposing bottings (4), both opening ends of each are connected to a gas distribution path (6) and a gas collection path (6'). The direction is fixed while keeping the opening open.

In the gas exchange function part (1) of the oxygenator of the present invention,
Gas containing oxygen is supplied from the gas inlet (10) to the gas distribution path (6), flows inside the hollow fiber membrane (!1), and passes through the hollow fiber membrane (3) in the contact chamber (5). The gas exchanges with the blood, resulting in a gas with decreased oxygen and increased carbon dioxide, which is led to the gas collection path (6') and then passed through the gas outlet (1).
1). Note that the oxygen-containing gas supplied from the gas inlet (10) may of course be pure oxygen.

On the other hand, blood drawn from the human body (venous blood) is introduced into the blood rectification chamber (14) through the blood introduction port (12), then supplied to the contact chamber (5), and then fed into the contact chamber (5). Gas containing oxygen flowing inside the fiber membrane (3) and the hollow fiber membrane (3)
After the blood is converted from venous blood to arterial blood while performing gas exchange through the gas exchange function section (1) and heat exchange function section (2),
) is supplied to the heat exchange function section (2) through a blood flow path (7) that connects the blood flow path (7).

Figure 1 shows an example in which the contact chamber is divided into three chambers by two blood flow channels (7), but the number of chambers may be any number as long as it is two or more; Although it is preferable that the number is large, it is practically preferable that the number is about 3 to 10 when considering all workability.

FIG. 6 is a partial sectional view showing another embodiment of the small chamber and the blood flow path (7) adjacent thereto. The cross-sectional shape of the blood flow path (7) may be any shape as long as it narrows the width in the thickness direction of the contact chamber, including those shown in FIGS. 1 and 5. It is preferable to have a cross section with a curved surface as shown in the figure in order to avoid blood stagnation. The purpose of providing the blood flow path (7) inside the contact chamber (5) is to prevent blood channeling by causing turbulence in the blood flow in the thickness direction of the contact chamber, and at the same time to prevent blood channeling in the thickness direction of the contact chamber. This is to equalize the oxygen and carbon dioxide concentrations in the blood across the cross section and improve gas exchange.

As shown in FIGS. 1 and 3, the width of the contact chamber of the blood flow path in the thickness direction is narrowed so that adjacent blood flow path sections are arranged alternately in upper and lower positions. is preferable.

Next, the dimensions of the contact chamber in the oxygenator of the present invention will be explained. The length b of the small chamber in the blood flow direction is preferably larger than the maximum thickness a of the small chamber. If a is larger than b, the flow of blood in the thickness direction of the chamber becomes dominant, and if blood stagnates in the corner of the chamber (near the boundary with the blood flow path of the chamber) and air bubbles are mixed in, defoaming may become difficult. There is.

It is preferable that the thickness θ of the blood flow path is less than half of the thickness a of the small chamber in order to achieve the effect of installing the blood flow path.

The width w1 of the contact chamber, that is, the distance between the two botting materials, is selected at an optimum value in relation to the blood flow rate and the thickness a of the small chamber, but in order to form a preferable flat blood flow in the contact chamber. is the width W of the contact chamber is 3 of the thickness a of the contact chamber
It is preferable to set it to about 60 times. If it is smaller than 3 times, the effect of the surface of the botting material on the blood flow becomes large, and the processability is also poor, which may result in unfavorable adhesion. Moreover, if it is larger than 60 times, it becomes difficult to make blood flow evenly over the entire hollow fiber membrane surface, and it becomes difficult to completely suppress channeling.

The hollow fiber membrane in the contact chamber is arranged so that blood circulates approximately in the n2 direction of blood flow. The blood flow direction according to the present invention is
It does not refer to the flow direction of the blood flow actually formed when blood flows into the total contact chamber, but rather refers to the direction from the inlet to the outlet of blood within the contact chamber. The angle between the blood flow direction and the hollow fiber should be at least 4 to suppress channeling.
It is necessary that the angle is 5 degrees, and it is most preferable that the angles are perpendicular to each other. This is because blood flows across a hollow fiber membrane.
This is thought to be due to small disturbances in blood flow occurring around the hollow fiber membrane. In addition, it is preferable that the large number of hollow fiber membranes arranged in the small chamber be such that each hollow fiber membrane is arranged parallel to the central axis of a bundle of these hollow fiber membranes. The hollow fiber membranes may be arranged as a bundle and wound at an angle of up to 4° to the central axis of the bundle of hollow fiber membranes.

The filling rate of the hollow fiber membranes stored in each small chamber is 10 to 55%.
It is preferable that The filling rate here refers to the ratio of the cross-sectional area occupied by the hollow fiber membrane to the cross-sectional area of the valley chamber in a plane parallel to the blood flow direction of the contact chamber. If the filling rate is less than 10%, blood channeling is likely to occur (it is difficult to obtain the effect of blood turbulence), and if it is more than 55%, blood flow resistance becomes excessive and hemolysis may be induced. Although the filling rate of the Otsuka thread membrane in the valley chambers may be different for each chamber, it is more convenient for processing and manufacturing to make them equal.

Various types of hollow fiber membranes can be used to be installed in the oxygenator of the present invention, such as cellulose-based, polyolefin-based, polysulfone-based, polyvinyl alcohol-based, silicone H'tl-based, PMMA-based, etc. Homogeneous or porous hollow fiber membranes of various materials can be used. However, a porous membrane made of polyolefin threads is used as a membrane that has excellent durability and excellent permeability through the body.

Also on the instep, the micro wall pores of the membrane are formed in the spaces between the fibrils created by the fibrils stacked many times from one side to the other and the knots that anchor both ends of the fibrils. Particularly preferred are membranes in which the fibrils are interconnected between the walls and extend from one side of the membrane to the other. Examples of such hollow fiber membranes include: For example, 9-fiber membranes in polypropylene and hollow polyethylene fibers
H? , trade name (manufactured by Mitsubishi Rayon Co., Ltd.).

The struts (9), which may be provided in the blood flow path (7), create turbulence in the blood flow flowing in the contact chamber, and at the same time, the hollow fiber membrane (3) in the small chamber increases the blood flow by causing the blood to flow. Road (7)
It is preferable in the present invention to provide all the struts (9), since this can completely prevent hemolysis and the like from occurring due to the abnormally high filling rate of the hollow fiber membrane (3) in this area. It is a mode.

Botting material (4) Polyurethane with good adhesiveness, unsaturated polyester,
It can be easily manufactured by integrating it with a hollow fiber membrane using EBOKI 7 resin or the like.

Part of the heat exchange function section (2) includes a heat exchange medium inlet (18) through which the heat exchange medium flows, a heat exchange medium outlet (19X heat exchange medium flow path (20), , (2o'), and (
It has a blood flow path (7), a contact chamber in which a second hollow fiber bundle (16) is disposed, and a blood outlet (13), and is provided with heat exchange means. The heat exchange means disposed within the heat exchange function section (2) includes a plurality of hollow fibers (17) for flowing a heat exchange medium such as melted water into the heat exchange section (2). It is arranged so as to be substantially perpendicular to the direction toward the outflow port (13) (blood flow direction). Hollow fiber (17
) When arranged in this manner, the heat transfer resistance on the blood membrane side can be reduced, and the heat exchange efficiency between the blood and the heat exchange medium can be increased. It is possible to form it as compact.

The material for the hollow fibers (17) for flowing the heat exchange medium has a thermal conductivity of 10-5 ca, t/cm/s e
Any material can be used at temperatures above c/℃, and in terms of monthly cost, examples include cellulose-based, polyolefin-based, silicone resin-based, acrylonitrile thread 1 fat, polymethyl methacrylate, and tomato-based lees 1 Fat, etc. can be mentioned. The hollow fiber has an inner diameter of 50 to 1000 mm.
A material having a wall thickness of about 2 to 200 microns can be used, and a non-porous film is preferable from the viewpoint of thermal conductivity.

The inner diameter of the hollow fiber depends on the application, but for a heat exchanger for an oxygenator, if it is too small, the pressure drop of the heat exchange medium flowing through the hollow fiber becomes large, and the heat exchange medium flow path (: ?n)
, (2rl') sealability and circuit operability deteriorate. On the other hand, if the hollow fibers are too thick, the heat transfer coefficient of the liquid flowing inside the hollow fibers will be small, and the volume occupied by the hollow fibers per unit heat transfer area will also be large, resulting in a large 1t1. do. For this reason, the inner diameter is preferably about 200 to 500 μm. The thinner the wall thickness is, the better in order to increase the heat transfer coefficient, but from the viewpoint of strength and workability, it is especially preferable to use a wall thickness of 10 to 150 μm.
It is preferable to set it as approximately.

In FIG. 1, there is only one contact chamber in which the second hollow fiber bundle (16) is disposed, but it may be divided into a plurality of small chambers as in the gas exchange function section (1). In addition, in this example, the blood after perfusing the gas exchange function part (1) is transferred to the heat exchange function part (2).
However, conversely, blood is supplied to the heat exchange function part (2) and heat exchange is performed first, and then the gas exchange function part (2) is supplied with blood.
Gas exchange may be performed in step 1), or gas exchange may be performed in any order by arranging the first fiber bundle or the second hollow fiber bundle in any small chamber of the contact chamber of the oxygenator of the present invention. It is also possible to exchange heat with・[Effects of the Invention] According to the artificial lung of the present invention, blood stagnation and channeling do not occur, and turbulence easily occurs in the blood flow (even when blood is perfused with low pressure drop). The amount of oxygen and carbon dioxide gas exchanged per unit membrane area through the thread membrane is large, and 9
In addition, it has the advantage of being easy to process, making it inexpensive, and reducing the amount of blood pumped out of the body, reducing the burden on the patient.

1. Because the heat exchanger is formed by partially touching the gas exchange function part, it is necessary to assemble the complicated circuit and remove bubbles from each part separately at the beginning of operation. It is an inexpensive oxygenator that is small, lightweight, and easy to process because it is lightweight and uses polymers that have low reactivity with blood. If it is available to all users.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway vertical sectional view of an embodiment of the oxygenator module of the present invention, and FIG. 2 is a partially cutaway plan view. Figures 3a to 3c are partially enlarged sectional views showing other aspects of the small chamber and the blood flow path. 1: Functional part 1 2: Functional part 2 5: Hollow fiber membrane 4: Potting material 5: Contact chamber
6: Gas distribution path 6': Gas collection path 7; Blood flow path 8: First lactic filament bundle 9: Strut 10: Gas inlet 11: Gas outlet 12: Blood inlet 15; Blood outlet 14 : Blood rectification chamber 15: Blood collection chamber 16: Second medium thread bundle 17: Hollow fiber 18: Heat exchange medium population 19: Heat exchange medium outlet 20.2
0': Heat exchange medium flow path 21: Partition Temporarily opened hole a: Maximum thickness of small chamber b: Maximum length of small chamber e: Thickness of blood flow path W: Width of contact chamber 1 figure

Claims (1)

[Claims] It has a blood inlet, a blood outlet, a gas inlet and a gas outlet, a heat exchange medium inlet and a heat exchange medium outlet, and has a generally shallow box shape as a whole, and has a contact chamber inside. A first hollow fiber bundle consisting of a large number of gas exchange hollow fibers fixed at both ends, and a second hollow fiber bundle consisting of a large number of heat exchange hollow fibers fixed at both ends. , the contact chamber is composed of a blood flow path whose width is narrowed by a baffle plate and a plurality of small chambers separated through the blood flow path, and the first and second
The hollow fiber bundle is a hollow fiber membrane oxygenator with a built-in heat exchanger, each of which is installed in a separate small chamber parallel to the baffle plate.