JPH0819601A - Artificial lung - Google Patents

Abstract

PURPOSE:To provide an artificial lung with which gas exchanging with a high efficiency can be achieved all the time regardless of the flow rate of blood. CONSTITUTION:A core part 29 which is substantially cylindrical when seen from the outside, is arranged at the center of a cylinder body 21. On the peripheral surface of the core part 29, a plurality of ribs 30 axially extending along the core part 29, are arranged at equal intervals in the sectional circumferential direction of the core part 29. On the passages formed between each pair of ribs 30 on the peripheral surface of the core part 29, wave part 32 are formed in such a way that the radius of an axially different place is relatively enlarged or reduced.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a hollow fiber membrane type artificial lung.

[0002]

2. Description of the Related Art As is well known, as a medical device for artificially exchanging blood gas, a hollow fiber membrane type artificial lung having a structure in which a hollow fiber membrane is used as a treatment membrane is known. That is, a large number of hollow fiber membranes form a large number of blood flow paths and gas flow passages in the container, and blood (venous blood), gas (oxygen or oxygen, air, and dioxide) are passed through the hollow fiber membranes. (Composed of carbon) and oxygen is added to the blood and carbon dioxide in the blood is discharged into the gas at the same time.

As an example of such a membrane oxygenator, a hollow fiber membrane oxygenator having a structure shown in FIG. 5 has been conventionally provided. In the figure, reference numeral 1 indicates a cylindrical tubular body, and both ends of the tubular body 1 are expanded in diameter to become tubular body heads 2a and 2b. A hollow fiber bundle 4 having a large number of hollow fibers bundled therein is housed in the cylindrical body 1 having the above-described structure. The hollow fiber bundle 4 is formed in a cylindrical shape, and a core portion 9 connected to a lid body 8 described later is inserted and arranged in a central space 4a thereof. After the hollow fiber bundle 4 is housed in the tubular body 1, both ends of the hollow fiber bundle 4 are potting materials 5, 5 such as polyurethane resin.
Are fixed in the cylindrical body 1 by the above, and the hollow fibers constituting the hollow fiber bundle 4 are opened at the outer end surfaces of the potting materials 5, 5.

The cylindrical body 1 has both openings 6a and 6b.
The lids 7 and 8 are attached so as to cover the. The lids 7 and 8 are each formed in a cap shape that is mounted in a hermetically sealed state with respect to the cylindrical body 1, and a blood introduction port projection tube 10 into which blood is introduced into the lid 8 below (lower in the figure) and The core portion 9 that introduces the blood introduced from the blood inlet pipe 10 to the upper portion of the cylindrical body 1 is connected. At the upper end of the core portion 9, a plurality of windows 11 for letting out the introduced blood into the cylindrical body 1 are opened at equal intervals along the circumferential direction of the cylindrical body 1. On the outer peripheral surface of the core portion 9, a plurality of ribs 12 extending along the axial direction of the core portion 9 are arranged at equal intervals in the circumferential direction of the cross section of the core portion 9. A discharge tube 13 for discharging the blood introduced into the cylinder 1 is provided below the cylinder 1. Flowing pipes 14a and 14b for introducing gas into the inside of each hollow fiber constituting the hollow fiber bundle 4 and discharging the gas to the outside of the cylinder 1 are provided on the side portions of the cylinder heads 2a and 2b (however). , There may be a plurality of distribution pipes 14b).

In the above structure, blood is introduced into the inlet port 10
Hollow fiber which is introduced into the core part 9 from the core part, hits the potting material 5 at the upper part, and then passes through the window 11 to the region between the core part 9 and the tubular body 1 to form the hollow fiber bundle 4. It flows through the space to reach the potting material 5 below, and is discharged from the discharge projection tube 13 to the outside of the cylindrical body 1. Gas is each hollow fiber bundle 4
Blood is exchanged for gas through the hollow fiber membranes that make up the hollow fiber membrane.

[0006]

The conventional hollow fiber membrane type artificial lung (blood processing apparatus) has the following drawbacks. That is, for example, when the blood flow rate changes significantly (in the case of open heart surgery, in the range of about 1 to 7 liters per minute), such as during open heart surgery, when the flow rate is within a certain range, the blood is entirely in the hollow fiber converging body 4. However, when the flow rate is out of the above range, the blood is unevenly distributed between the upper end of the core portion 9 and the discharge projection tube 13 in the path where the flow path length is shortened, and only between the specific ribs 12, 12. Alternatively, the cylinder 1 and the hollow fiber bundle 4
There is a problem that a flow path is formed only between the outer circumference of the hollow fiber and the outer periphery of the hollow fiber (so-called channeling), and blood does not reach the entire hollow fiber bundle 4, and the gas exchange efficiency decreases. In addition, the blood flowing through the central space 4a hits the upper potting material 4 and the direction of the blood changes from 90 ° to 180 °. The amount of change in the contact is different depending on the amount of blood. Blood does not reach the entire hollow fiber bundle 4 and causes a decrease in gas exchange efficiency. further,
At high flow rate, blood hits the upper potting material 5 and 90
There is a problem of blood damage if the direction is changed more than °. The amount of blood filled in the central space 4a is also preferably inward as viewed from the goal of minimizing the filling amount of the entire circulation circuit.

The present invention has been made in view of the above-mentioned problems, and provides an artificial lung that can always obtain a high gas exchange efficiency regardless of the blood flow rate, has less problems of blood damage, and has a small blood filling amount. The purpose is.

[0008]

The present invention has the following features to attain the object mentioned above. That is, in the artificial lung according to claim 1, a hollow fiber converging body formed by concentrating hollow fibers in a cylindrical shape is housed in a cylindrical body having a blood outlet port protruding from one end thereof, and the hollow fiber converging body is also housed. A columnar core part having a plurality of flow passages for blood introduced from the blood introduction port at the end part on the outer peripheral side is housed in the center part of the body, and these hollow fiber bundles and core parts are fixed by potting material, In a hollow fiber membrane oxygenator in which cap-shaped lids each having an inlet and a gas inlet are integrally connected to both ends of the tubular body, in a plurality of blood channels of the core are circumscribed to the core. The means for changing the direction of the flow of the blood introduced from the blood introducing port at the end toward the hollow fiber converging body to be positively moved away from the outer peripheral side of the core part is provided. The means.

In the artificial lung according to the second aspect of the present invention, the means for solving the above-mentioned problems is that the plurality of flow paths of the core portion are arranged in a spiral shape from the blood introduction port at the end portion toward the downstream side.

In the artificial lung according to a third aspect of the present invention, the means for solving the above-mentioned problems is such that the cross-sectional area of each of the plurality of flow paths of the core portion is repeatedly reduced and expanded from the blood introduction port toward the downstream.

In the artificial lung according to the fourth aspect, the fact that blood does not circulate inside the core portion is a means for solving the above problems.

[0012]

In the present invention, the direction of the flow of blood flowing in parallel to the core portion is positively changed over the entire side surface of the core portion existing like a plug in the center of the hollow fiber concentrating body, and the blood flow rate is wide range. Directs the flow of blood to the hollow fiber bundle. As a result, the blood flows toward the hollow fiber bundle with a wide range of flow rates, and a high gas exchange rate is obtained. By arranging the flow path provided in the core part in a spiral shape from the blood introduction port toward the downstream, the flow direction of the blood introduced into the flow part is changed tangentially from the sliced cross section of the core part. Therefore, the blood flows toward the hollow fiber bundle, and the above-mentioned effect is obtained. Further, the blood introduced into the flow path by repeatedly reducing and expanding the cross-sectional area of the flow path provided in the core portion from the blood introduction port toward the downstream, while the flow path cross-sectional area is decreasing, The flow direction is changed in the direction away from the side surface of the core portion. Next, while the cross-sectional area of the flow channel is expanding, the area where the cross-sectional area is reduced is filled with blood whose flow direction has not been changed, and the next cross-sectional area is reduced. I will do it. As a result, the flow direction of the blood is changed mainly in the cross-sectional area reduction portion, and the blood flows toward the hollow fiber converging body each time the cross-sectional area reduction and expansion are repeated, and the above-mentioned effect is obtained. To be In addition, since blood does not flow inside the core part, blood flows from the inlet to one end of the core part, and flows into the flow path while slightly changing its direction. As a result, the direction of flow of blood is hardly changed before flowing into the flow path, so that it does not adversely affect the flow direction to the hollow fiber bundle, and the problem of blood damage is small. In addition, the filling amount of the central space in the cylinder can be eliminated.

[0013]

EXAMPLE An example of the artificial lung of the present invention will be described below with reference to FIGS. 1 to 4. Reference numeral 21 in FIG. 1 denotes a cylindrical tubular body, and both end portions of the tubular body 21 are a lid 22a,
It is closed by 22b. This lid 22a, 22b
A distribution pipe 23a (gas introduction port) for introducing gas to the inside of the hollow fiber and a distribution pipe 23b for discharging gas to the outside are provided therein. A hollow fiber bundle 24, which is a bundle of a large number of hollow fibers, is housed in the cylindrical body 21 having the above structure. The hollow fiber bundle 24 is formed in a cylindrical shape, and a core portion 29 described later is inserted and arranged in the central space 24a of the hollow fiber bundle 24. The hollow fiber bundle 24 is housed in the tubular body 21, and both ends thereof are fixed in the tubular body 1 by potting materials 25, 25 such as polyurethane resin. Each hollow fiber constituting the hollow fiber bundle 24 is opened.

The cylindrical body 21 is formed in a tapered shape whose diameter increases toward the top (upward in the figure) at an angle of about 1.5 degrees. The lid 22b attached to the bottom of the cylinder 21 has
An inlet projection tube 26 (blood inlet) for introducing blood is provided inside the cylindrical body 21. The inlet projection tube 26 is projected inward of the lid body 22b, and when the lid body 22b is attached to the tubular body 21, the tip thereof is potted at the lower portion of the hollow fiber focusing body 24 which is housed in the tubular body 21. The material 25 is fitted into a fitting hole 24b provided in communication with the central space 24a. At the tip of this inlet port projection tube 26,
The radiating portion 27 is formed so that its inner diameter increases in a taper shape as it goes in the distal direction. A discharge projection tube 28 for discharging the blood supplied from the introduction port projection tube 26 into the cylinder body 21 is provided on the cylinder body 21.

At the central portion of the cylindrical body 21, a core portion 29 having a substantially cylindrical shape when viewed from the outside is arranged. The core portion 29 is made of a resin such as polypropylene and is solidly formed. The upper end portion of the core portion 29 is submerged in the potting material 25 located at the upper portion, and the position of the upper end portion is maintained. The outer peripheral surface of the core portion 29 is formed into a smooth surface, and a rib 30 extending along the axial direction of the core portion 29 is formed on the outer peripheral surface as shown in FIGS. 2 and 3. A total of eight are arranged in a radial pattern of 29 at equal intervals. In the groove portion 31 formed between the ribs 30 on the outer peripheral surface of the core portion 29, an undulating portion 32 having a shape in which the radial dimension at different locations in the axial direction is relatively enlarged or reduced is provided. The undulating portion 32 has a tapered shape in which the straight line connecting the vertices of the expanded diameter portion along the lengthwise direction of the core portion 29 is inclined upward by 1.5 degrees with respect to the central axis of the core portion 29 and is spaced apart. Has been formed. Core part 29
As shown in FIG. 1, the lower end portion of the inlet pipe 26
A conical portion 33 is provided for diffusing blood introduced from the core portion 29 in the radial direction.

In the artificial lung, the lid 22a is positioned above, blood is introduced into the cylindrical body 21 through the inlet projection tube 26 in this state, and oxygen or oxygen, air and carbon dioxide are introduced through the flow tube 23a. By introducing the mixed gas, the gas of blood is exchanged. The blood introduced from the inlet port projection tube 26 is uniformly distributed in the flow path when flowing through the conical portion 33. Further, since blood does not flow or permeate into the core portion 29, blood flows smoothly from the conical portion 33 toward each flow path. When the blood rising along the outer peripheral surface of the core portion 29 hits the undulating portion 32, the flow path is changed in the radial direction of the hollow fiber focusing body 24 to flow, and the blood flow is dispersed throughout the hollow fiber focusing body 24. The blood that rises in the tubular body 21 continues to rise until it hits the potting material 25 on the upper side, and during the rise, blood and gas exchange gas through the hollow fiber membrane. The blood that has reached the upper potting material 25 is discharged to the outside of the cylindrical body 21 via the discharge projection tube 28.

Therefore, according to the artificial lung, the blood introduced from the introduction port projecting tube 26 flows while being dispersed throughout the hollow fiber converging body 24, and the blood flowing in the vicinity of the core portion 29 hits the undulating portion 32 to form a cylinder. Since it is dispersed in the outer peripheral direction of the body 21, a contact area between the blood and the hollow fiber concentrating body 24 is secured, high gas exchange efficiency is maintained, and blood is constantly circulated throughout the body 21 to form a body. The stagnant portion of blood in 21 is eliminated, and the gas exchange efficiency is improved. in addition,
Since the change in the direction of blood flow near the inlet is reduced, there are many problems of blood damage. Since blood does not circulate inside the core portion 29, the amount of blood filled in the central space of the core portion 29 can be eliminated, and blood flows smoothly from the conical portion 33 toward the flow path on the outer peripheral surface of the core portion 29. Efficiency is further improved.

A second embodiment of the present invention will be described below with reference to FIG. The artificial lung of the present embodiment has a plurality of spiral ribs 34 on the outer peripheral portion of the core portion 29. The ribs 34 are attached to the same extent as the ribs 30 of the first embodiment in the axial direction of the outer peripheral surface of the core portion 29, and are wound around the outer peripheral surface of the core portion 29 by about 1/4 in the circumferential direction of the cross section. It is formed in a curved shape. According to the artificial lung of this example,
The blood flowing from the inlet projection tube 26 changes its flow direction toward the outer peripheral direction of the hollow fiber focusing body 24 by flowing along the ribs 34 and is dispersed throughout the hollow fiber focusing body 24 to form a swirling flow. The area of contact with each hollow fiber constituting the hollow fiber bundle 24 is secured, the blood is prevented from staying in the tubular body 21 more reliably and efficiently, and the efficiency of gas exchange is further improved. Further, regarding the blood damage and the blood filling amount, the same effect as that of the artificial lung described in the first embodiment is obtained.

The discharge projection tube 28 may be provided in a place other than the upper portion of the cylindrical body 21. The undulating portion 32 is the core portion 2
It is also possible for each part of the circumferential direction of 9 to have a shape that relatively expands and contracts in the radial direction. In the second embodiment, the winding of the rib 34 may be other than one quarter of the core portion 29 as long as blood can be sufficiently diffused throughout the hollow fiber bundle 24. In this case, the undulations 32 need not be installed.

[0020]

As described above, according to the oxygenator of the first aspect, the blood is introduced into the end portions of the plurality of blood flow passages of the core portion toward the hollow fiber bundle circumscribing the core portion. Since a means is provided to positively change the direction of the flow of blood introduced from the mouth so that it is moved away from the outer peripheral side of the core part, blood flows toward the hollow fiber concentrator in a wide range of flow rate and high gas exchange. The rate is obtained.

In the oxygenator of the second aspect, since the plurality of flow passages of the core portion are spirally arranged from the blood introduction port at the end portion toward the downstream side, the blood introduced into the flow passage is the core. The flow direction will be changed tangentially from the cross section of the section, and blood will flow toward the hollow fiber bundle,
A high gas exchange rate is obtained.

In the artificial lung according to the third aspect, the cross-sectional area of each of the plurality of flow paths of the core portion is configured to be repeatedly contracted and expanded from the blood introduction port to the downstream side. Is mainly changed in the cross-sectional area reduction part, and the blood flows toward the hollow fiber converging body every time a plurality of cross-sectional area reductions and expansions are repeated, and a high gas exchange rate is obtained.

In the artificial lung according to the fourth aspect, since the blood does not flow through the inside of the core portion, the direction of the flow of the blood is hardly changed before flowing through the flow path. In addition, the problem of blood damage is small, the amount of filling in the central space is eliminated, and blood smoothly flows toward the flow path along the outer peripheral surface of the core portion, further improving gas exchange efficiency.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a first embodiment of an artificial lung of the present invention.

FIG. 2 is a plan view showing a core portion used in the embodiment.

FIG. 3 is a partial cutaway view showing details of a core portion used in the embodiment.

FIG. 4 is a front sectional view showing a second embodiment of the artificial lung of the present invention.

FIG. 5 is a front sectional view showing a conventional artificial lung.

[Explanation of symbols]

 21 Cylindrical Body 24 Hollow Fiber Focusing 23a Gas Inlet Port (Distribution Pipe) 25 Potting Material 26 Blood Inlet Port (Inlet Port Spouting Tube) 28 Discharge Spouting Tube 29 Core Part 30 Rib 32 Undulating Part 34 Rib

Claims (4)

[Claims] 1. A hollow fiber converging body formed by concentrating hollow fibers in a tubular shape is housed in a cylindrical body having a blood outlet port projecting from one end thereof, and the hollow fiber converging body has an end at the center thereof. A columnar core part having a plurality of flow paths of blood introduced from the blood introduction port of the outer peripheral side is housed, and these hollow fiber bundles and core parts are fixed by a potting material, and a blood introduction port and a gas introduction port In a hollow fiber membrane-type artificial lung in which cap-shaped lids each having are integrally connected to both ends of the tubular body, in a hollow fiber bundle circumscribing the plurality of blood channels of the core part. An artificial lung, characterized in that means is provided for positively changing the direction of the flow of blood introduced from the blood inlet port of the end portion so as to be positively moved away from the outer peripheral side of the core portion. 2. The artificial lung according to claim 1, wherein the plurality of flow paths of the core portion are arranged in a spiral shape from the blood inlet port at the end portion toward the downstream side. 3. The cross-sectional area of each of the plurality of flow paths of the core portion is
The artificial lung according to claim 1, wherein the artificial lung has a form in which contraction and expansion are repeated downstream from the blood inlet. 4. The artificial lung according to claim 1, wherein blood does not flow inside the core portion.