JPH01148265A - Blood filter - Google Patents

Abstract

PURPOSE:To drastically enhance air bubble removing capacity by preventing blood damage due to the adhesion of a platelet and the inferiority of a bubble venting property at a priming time, by generating a revolving stream by a ring-shape air bubble separator forming a curved blood flow passage between said separator and the inner surface of the main body of an air bubble separation part. CONSTITUTION:A ring-shape air bubble separator 7 forming a curved blood flow passage between said separator and the inner wall surface of the main body 4 of an air bubble separation part and an air discharge port 6 is provided to the top part of the conical wall 4a covering the upper end opening of the main body 4 of the air bubble separation part and a stepped surface 4b is formed between the main body 4 of the air bubble separation part and a blood filter part main body 8. A blood filter part 3 consists of the cylindrical blood filter part main body 8 concentrically connected to the lower end of the main body 4 of the air bubble separation part, a filter material 10 and a blood outflow port 9.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to the prevention of foreign matter and air bubbles in blood flowing through extracorporeal circulation blood circuits such as artificial heart-lung machines, artificial kidney machines, and devices for separating blood cell components and plasma components. Regarding blood filters that remove
In particular, it relates to a blood filter with improved bubble removal performance.

[Conventional technology]

Conventionally, a blood filter 1 includes a cylindrical housing A made of polycarbonate resin or the like, as shown in FIG. 9(a), and a blood inlet port housed in the housing A. The filter medium 10 is interposed between the blood outlet 5 and the blood outflow port 9, and is composed of a filter medium 10 formed into a cylindrical shape by sandwiching a screen mesh with an opening of 20 to 50 μm between plastic nets and folding it into pleats. Then, to prevent air bubbles from directly flowing into the filter medium 10,
The blood inlet 5 is formed so that the blood B flows in the tangential direction of the cylindrical housing A and causes a swirling flow within the housing A. Furthermore, an example in which a continuous foam body is fitted between the blood inflow port 5 and the filter medium 10 to prevent air bubbles from directly flowing into the filter medium 10 is also known. Therefore, in the conventional blood filter 1, the blood B that enters from the blood inlet 5 becomes a swirling flow within the housing A, and the small-mass air bubbles riding on the swirling flow in the blood B move to the center of rotation due to the action of centrifugal force. Bubbles are separated by taking advantage of the fact that they gather together. Therefore,
Since air bubbles are constantly affected by buoyancy in blood B,
Separated air bubbles are stored in the upper part of the shaft center of the housing A, and the air discharge port 6 is provided in the upper part of the shaft center of the housing A.
These bubbles were separated and removed. Furthermore, air bubbles that were not removed from blood B due to centrifugal force due to swirling flow, etc.
That is, the air bubbles that were not caught in the swirling flow of blood B were filtered by the filter medium IO. The aforementioned blood inlet 5 and filter medium 1O
In an example in which an open foam was provided between the two, the removal was performed using the open foam.

[Problems to be Solved by the Invention] However, in the blood filter 1 described above, the blood B flowing into the housing A from the blood inflow port 5 is
As shown in b), at the blood inlet 5, it directly collides with the flow of blood B that has already entered the housing A and is given a swirling flow, and the flow is disturbed before it is given a swirling flow. This makes it difficult for air bubbles to ride on the swirling flow of blood B.

Therefore, in this blood filter 1, blood B
By placing most of the air bubbles in the swirling flow of
It became difficult to separate the air bubbles in blood B, and the filter medium 1o
Many air bubbles flow into the vicinity. And blood B
The bubbles inside collide with the filter medium 10, and gradually pass through the filter medium 1.0 due to pressure fluctuations generated by pulsation caused by the pump. Further, in the above-mentioned bubble removal example using the open foam, there were disadvantages in terms of blood damage due to adhesion of platelets, increased pressure loss, and difficulty in removing bubbles during brimming.

Therefore, the present invention was made in view of the above circumstances, and although it has a simple structure, it prevents blood damage due to platelet adhesion, increase in pressure loss, poor bubble removal performance during brimming, etc. The purpose of this invention is to provide a blood filter that can dramatically improve bubble removal performance.

[Means for solving problems]

In order to solve the above-mentioned problems, the blood filter of the present invention is hollow and has a substantially conical outer shape, has an air outlet at the upper end, and has an air outlet at the lower end in a direction tangential to or approximating the tangential line to the horizontal side surface. A bubble separator main body in which a blood inflow port protruding from the air bubble separator body is disposed, and an inner surface of the bubble separator main body that is located below the bubble separator main body and has a smaller outer diameter than the bubble separator main body. a ring-shaped bubble separator forming a curved blood flow path; a bubble separating section located below the bubble separating section and having a blood outflow port at the lowest end;
and a blood filtration section in which a filtering medium is housed, the air bubbles contained in the blood flowing in from the blood inlet come into contact with the air bubble separator, are separated, and are discharged from the air outlet, so that the air bubbles are separated. The structure is such that blood is filtered by a surface filter medium and then discharged from a blood outlet I.

[For production]

According to the configuration described above, the blood flowing in from the blood inflow port is located on one side of the bubble separator main body, has a smaller outer diameter than the bubble separator main body, and is located between the inner surface of the bubble separator main body and the inner surface of the bubble separator main body. The ring-shaped bubble separator that forms a curved blood flow path eliminates the effects of sudden expansion of the flow path from the blood inlet and the flow of blood within the bubble separator body, so that the flow of blood is reduced. The flow is controlled so that no turbulence occurs and a swirling flow occurs. Although some blood passes gently through the bubble separator, most of the bubbles in the blood do not pass through the bubble separator, but instead ride on the swirling flow and collect above the center of rotation due to centrifugal force and buoyant force, leading to the air discharge port. separated from

(Example) Hereinafter, an example of the present invention will be described in detail based on FIGS. 1 to 8.

Figure 1 is a perspective view showing the blood filter of the present invention, Figure 2 is a perspective view showing the blood filter of the present invention;
The figure is a cross-sectional view of the blood filter, and FIG. 3 is a cross-sectional view of the filter medium in FIG. 2 along the line ■-■. In the figure, 1 indicates a blood filter, and the blood filter 1 includes a bubble separating section 2.
and a blood filtration section 3, the bubble separation section 2 includes a bubble separation section main body 4 which is hollow and has a substantially conical outer shape, and a tangential direction or a tangential line on the horizontal side surface of the lower part of the bubble separation section main body 4. A blood inflow port 5 provided protruding in a direction approximating
, an air outlet 6 provided at the top of the conical wall 4a covering the upper end opening of the bubble separator main body 4, and an inner wall surface of the bubble separator main body 4 having an outer diameter smaller than that of the bubble separator main body 4. and a ring-shaped air bubble separator 7 forming a curved blood flow path between the air bubble separator 7 and the air bubble separator 7. The blood filtration section 3 includes a cylindrical blood filtration section main body 8 concentrically connected to the lower end of the bubble separation section main body 4, and a blood filtration section main body 8 provided concentrically on the lower surface of the blood filtration section main body 8. It consists of an outflow port 9 and a filter medium 10 located between the blood outflow port 9 and the blood inflow port 5 and housed within the blood filtration section main body 7.

The bubble separation section main body 4 and the blood filtration section main body 8 are made of synthetic resin such as polycarbonate, and are integrally molded. A stepped surface 4b is formed between the bubble separating section main body 4 and the blood filtration section main body 8.

The blood inflow port 5 is made of resin such as polycarbonate similarly to the bubble separation unit body 4 and the blood filtration unit body 8, and is provided on the outer surface of the lower part of the bubble separation unit body 4 so as to protrude in the tangential direction. . The cross-sectional shape of the blood inlet 5 may be rectangular or circular.

The air outlet 6 is made of the same material as the bubble separator main body 4 and the blood filter main body 8. The air outlet 6 is provided at the top of the conical wall 4a that covers the upper end opening of the bubble separator body 4, that is, the air outlet 6 is provided approximately on an extension of the axis of the bubble separator body 4. The reason is as follows. That is, blood B flowing from the blood inflow port 5 in the tangential direction of the bubble separator main body 4 at a certain flow rate obtains a swirling flow, and the blood B is separated by centrifugal force.
This is to separate the air bubbles therein so that the air bubbles can be easily discharged from the upper air outlet 6 due to the buoyant force at the axial center of the bubble separator main body 4.

As shown in FIG. 3, the filter medium 10 is made into a cylindrical shape by sandwiching both sides of a screen mesh 11 made of polypropylene with an opening of 20 to 50 μm between nets 12 and 12 made of polypropylene, and folding this into a pleat shape. It is formed by The upper part of this cylindrical filter medium 10 is made into an impermeable part 10a by pouring and hardening polypropylene resin, ethylene vinyl acetate (EVA), polyurethane resin, synthetic rubber, polyolefin resin, etc. Then, the filter medium 10 is arranged with the impermeable part 10a of the filter medium 10 facing upward.
It is housed within the blood filtration unit main body 8. Also, filter medium 1
The lower end surface of the blood filter 0 and the bottom surface of the blood filtration section main body 8 are brought into close contact with each other using the various resins mentioned above. The reason for this is that the blood B does not pass through the filter medium 10 to the blood outflow port 9, that is, the blood B does not make a short pass. The opening is larger than Screen Mesh II, for example, 40 to 200 μm,
A defoaming mesh 14 preferably having a thickness of 100 to 180 μm is provided. The reason for this is that if the opening is too narrow, it will cause blood damage and pressure loss, whereas if the opening is too narrow, the air bubbles in the blood B will easily pass through the defoaming mesh 14 of the bubble separator 7, and the blood will This is because bubble removal from B may not be successful. This defoaming mesh 14 is made of resin such as polypropylene, nylon, or polyester. Further, the cylindrical frame 13 is made of a resin having a lower melting point than the material of the defoaming mesh 14.

The bubble separator 7 is housed within the bubble separator main body 4, and the step surface 4 between the lower end surface of the bubble separator 7 and the bubble separator main body 4
b is in close contact with the filter medium 10 to prevent blood B entering from the blood inflow port 5 from directly flowing into the filter medium 1O. A gap G is provided between the upper end surface of the bubble separator 7 and the conical wall 4a in which the air outlet 6 is provided. That is, this gap G is provided to allow air bubbles separated from blood B to flow. The air bubble separator 7 uses a rough anti-bubble mesh 1 to prevent the air bubbles in the blood B from riding on the swirl flow due to the turbulent flow immediately after the blood inflow from the blood inflow port 5 to flow into the filter medium 10 side.
It is sufficient if the flow of blood B can be controlled until the bubble separation of blood B in the swirling flow is completed, that is, until the mixed air bubbles get on the swirling flow. . Therefore, the defoaming mesh 14 does not need to be stretched over the entire surface of the cylindrical frame 13, and may be partially cut out.

The blood filter 1 having the above configuration is used, for example, in an artificial heart-lung machine M as shown in FIG. That is, the blood filter 1 is connected to the aorta of a human body 21 via a tube 20, and further connected to a blood reservoir 23 via a tube 22.

The blood reservoir 23 is connected to an oxygenator 28 via a tube 24, a pump 25, a tube 26, and a heat exchanger 27. The artificial lung 28 is connected to the blood filter 1 via a tube 29.

Next, the operation of the blood filter 1 having the above structure will be explained.

For example, the blood B in the blood storage Nj23 of the heart-lung machine M is
Pressurized by pump 25, tube 26,
The blood flows into the blood inlet 5 of the blood filter 1 via the heat exchanger 27, the oxygenator 28, and the tube 29. Blood B is
Since pressure is applied by the pump 25, the blood flows tangentially into the bubble separator main body 4 from the blood inlet 5 provided in the bubble separator 2 at a constant flow rate. This blood B is given a swirling flow and passes between the wall surface of the bubble separator main body 4 and the bubble separator 7, but the blood B, which has a high flow velocity in the swirling flow immediately after flowing into the blood inlet 5, is turbulent. , and the air bubbles in blood B do not follow the swirling flow and try to flow toward the filter medium IO side. However, the air bubbles are removed from the bubble removal mesh 14 of the air bubble separator 7.
As a result, it does not flow into the filter medium 1O side, but instead rides on the swirling flow. Therefore, the air bubbles in the blood B are removed from the air bubble separator main body 4.
The separation takes advantage of the fact that air bubbles with smaller mass gather around the center of rotation. Since the separated air bubbles are always under the action of buoyancy in the blood B, these air bubbles pass through the gap G and are stored in the upper part of the axis of the air bubble separator main body 4. The air is removed through an air outlet 6 provided in the conical wall 4a. After that, the blood B that has passed through the bubble separator 7 and the blood B that has passed through the gap G are both transferred to the filter medium 1.
0 to filter out other foreign substances. The filtered blood B is
The blood is sent from the blood outlet 9 through the tube 20 to the aorta of the human body 21 .

Next, the defoaming effect of the blood filter FA of the present invention and the conventional blood filter FB was actually measured under the following conditions.

This test was conducted according to the experimental flow shown in FIG. That is, the blood reservoir 23 is connected to the suction port of a pump 25 via a tube 24, and the discharge port of the pump 25 is connected to the sample blood filters FA, F via a tube 26.
Connected to the blood inlet of B, blood filters FA and FB
The blood outlet of blood filters FA and FB is connected to an ultrasonic bubble detector 31 via a tube 20, and the ultrasonic bubble detector 31 is connected to a blood reservoir 23 via a tube 20 and a clamp 32. Air outlet is Percyline 3
It is connected to the blood reservoir 23 via 3. An air injector 34 for blowing air into the blood is connected to the tube 24, and clamps 35 and 36 are also connected for switching the blood filters FA and FB for the sample.
are provided on tubes 26 and 20.

The blood filter FA is of the present invention and has a bubble separator as shown in FIG. 8(a). The blood filter FB is a conventional swirl flow type blood filter as shown in Fig. 8(b) and (C).
) There is no bubble separator as shown in the figure.

The filter media of the blood filters FA and FB are T-350 polyester mesh 40 μm, filtration area 650 crn,
Totch 12-/, effective height 6818, number of threads 40 is used.

The test will be conducted under the following conditions.

■The blood used is bovine blood (Ht35!I; ). ■
Sample blood filters FA (present invention) and FB (conventional example) have an average pressure on the filter inlet side of 200 ± 10, Hg
Filter fresh blood. ■Blood supply amount is 4It/1 with pump
n Send. (2) Air is caused to flow into the blood from the air injector 34 at 20 ee/. ■Ultrasonic bubble detector (tips-1000Micr) to detect air bubbles in bovine blood.

-e+++boli detection sys
tem Extracorporal techno
logies, INCIndiana polis,
USA). ■Keep the priming amount constant for both blood filters FA and FB.

The test results are shown in Table-1.

Note that the measurement conditions are as follows.

The number of air bubbles in bovine blood after the sample has passed through blood filters FA and FB is counted.

This bubble count is measured 600 times in 30 seconds. The quantity indicates the integrated value (average value of 5 measurements) of the maximum bubble diameter detected during each ultrasonic pulse irradiation. Small diameter bubbles (20μ
(values less than 1) were deleted because accurate counts could not be obtained.

In addition, in the embodiment, only the removal of air bubbles in blood has been described, but the present invention is not limited to blood, and can be applied to other medicinal solutions as well.

〔Effect of the invention〕

As described in detail above, the blood filter of the present invention is hollow and has a substantially conical outer shape, has an air outlet at the upper end, and has an air outlet at the lower end in the horizontal direction along the horizontal side or in a direction approximating the tangential line. A bubble separator main body in which a blood inflow port protruding from the air bubble separator body is disposed, and an inner surface of the bubble separator main body that is located below the bubble separator main body and has a smaller outer diameter than the bubble separator main body. a ring-shaped bubble separator that forms a curved blood flow path; a bubble separator that is located below the bubble separator, has a blood outflow port at the lowest end, and houses a filter medium; The blood flowing in from the blood inflow port is located below the bubble separator main body, has a smaller external shape than the bubble separator main body, and has a blood filtering section between the inner surface of the bubble separator main body and the inner surface of the bubble separator main body. The ring-shaped bubble separator that forms a curved blood flow path eliminates the effects of sudden expansion of the flow path from the blood inflow port and the flow of blood within the bubble separator body, so that blood flows smoothly. It is controlled so that no turbulence occurs and a swirling flow occurs. Although some blood gently passes through the bubble separator, most of the bubbles in the blood do not pass through the bubble separator, but instead ride on the swirling flow, collect above the center of rotation due to centrifugal force and buoyant force, and exit from the air outlet. separated.

Therefore, although it has a simple structure with a bubble separator, it significantly improves bubble removal performance while preventing blood damage caused by platelet adhesion, increased pressure loss, deterioration of bubble removal performance during brimming, etc. increase the target. Furthermore, if the bubble removal performance is made the same, it is possible to reduce the amount of brimming.

[Brief explanation of the drawing]

1 to 8 show embodiments of the present invention.
The figure is a perspective view showing the blood filter of the present invention, FIG. 2 is a sectional view of the blood filter, and FIG. 3 is a cross-sectional view of the filter medium of FIG.
4 is a perspective view of a bubble separator, FIG. 5 is an overall configuration diagram of an artificial heart-lung machine to which the blood filter of the present invention is applied, FIG. 6 is an explanatory diagram of the action of the blood filter, and FIG.
The figure is an experimental flow diagram of the blood filter, Figure 8 (a) is a sectional view of the sample blood filter FA, and Figures 8 (b) and 8 (C) are a plan view and a sectional view of the sample blood filter FB. 9 is a sectional view of a conventional blood filter. 1---Blood filter 2...Bubble separation part 3---Blood filtration part 4---Bubble separation part main body 4 a = = Conical wall (upper wall surface) 5------Blood inlet 6------Air outlet 7---Bubble separator 9---One blood outlet 10---Filtering material

Claims (5)

[Claims] (1) A bubble that is hollow and has an approximately conical outer shape, has an air outlet at the upper end, and a blood inlet at the bottom that protrudes tangentially or in a direction similar to the tangential line on the horizontal side surface. a ring-shaped ring that is located below the bubble separator body, has a smaller outer diameter than the bubble separator body, and forms a curved blood flow path between the bubble separator body and the inner surface of the bubble separator body; and a blood filtration part that is located below the bubble separator, has a blood outflow port at the lowest end, and houses a filter material. Air bubbles contained in the inflowing blood come into contact with the air bubble separator and are separated and discharged from the air outlet, and the blood from which the air bubbles have been separated is filtered by the filter medium and then discharged from the blood outlet. A blood filter characterized by comprising: (2) The blood filter according to claim 1, wherein at least a portion of the bubble separator is made of a mesh, and the opening of the mesh is larger than the opening of the filter medium. (3) The blood filter according to claim 1, wherein a gap is provided between the upper wall surface of the bubble separator main body and the bubble separator. (4) The blood filter according to claim 1 or 2, wherein the bubble separator is partially cut out. (5) The mesh opening of the bubble separator is 40 to 20
The blood filter according to claim 2, which has a diameter of 0 μm.