JPS5932142B2 - Hollow fiber membrane type blood processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a semipermeable membrane or a porous membrane, and uses principles such as osmosis, dialysis, ultrafiltration, and gas diffusion to move substances in the blood. The present invention relates to a blood processing device having an improved hollow fiber membrane bundle, in particular to a blood processing device having an improved hollow fiber membrane bundle in which the membranes are in the form of hollow fibers.

Conventionally, this type of blood processing equipment has been used to purify the blood by removing harmful substances from the blood of patients with renal failure, drug addiction, etc., as well as artificial liver equipment and artificial liver equipment that exchange oxygen and carbon dioxide gas. Widely used as lung devices, etc.

The present invention provides an improved device for use in these blood processing devices.

Such blood processing equipment generally bundles a large number of hollow fiber membranes, makes the cut surfaces of both ends face a closed space from the outside, introduces the fluid to be treated, such as blood, into one of the spaces, and then Many membrane membranes have a configuration in which the fluid that has passed through the membrane is collected in the other space from the cut surface at the other end and is discharged to an external discharge pipe.

Usually, something called a header is provided to form this space.

A bundle of hollow fiber membranes is often formed in a circular or flat shape.

An example of this type of blood processing apparatus is shown in FIG. 1, taking as an example a so-called cylindrical type vertical hemodialyzer in which hollow fiber membranes are bundled in a circular shape.

In FIG. 1, reference numeral 1 denotes an inlet header with a circular cross section, which is provided to guide blood into the internal space of the hollow fiber membrane 5 and to isolate it from the outside. Blood 10 is introduced from an inlet 20. .

1a is an exit side header with a circular cross section that is provided to collect the blood that has passed through the internal space of the hollow fiber membrane and discharge it from the outlet 20a into a tube of a certain size, and to isolate it from the outside. be.

2 so that the header 1 or 1a does not separate from the outer cylinder 3,
In addition, in order to guide the blood drawn into the header into the internal space of the hollow fiber membrane 5 without leaking to the outside, the header 1 or 1a is brought into close contact with the partition wall 6 that fixes the hollow fiber membrane group through the packing 12. It is a fixed cap provided on the

The outer cylinder 3 is preferably cylindrical and made of a transparent, hard synthetic resin so that its interior can be seen visually, and its internal space 9 is filled with several hundred to ten thousand hollow fiber membranes 5. There is.

Further, this outer cylinder 3 is provided with an inlet 4 and an outlet 4a for dialysate.

A large number of hollow fiber membranes 5 are filled in the internal space 9 of the outer cylinder 3, and both ends thereof are fixed in a fluid-tight manner by partition walls 6 having excellent blood compatibility.
Moreover, the internal space of the hollow fiber membrane 5 communicates with the internal space 8 of the header.

Furthermore, the partition wall 6 is generally made of polyurethane resin, and the partition wall 6 separates the internal space 8 of the header from the internal space 9 of the outer cylinder 3, and the internal space 8 of the header and the internal space 9 of the external cylinder 3 are hollow. Contact is made only through the wall membrane of the thread membrane 5.

That is, the introduced blood 10 enters the internal space of the hollow fiber membrane via the header internal space 8, and harmful substances in the blood are discharged into the internal space 9 of the outer cylinder 3 through the wall membrane of the hollow fiber membrane. The purified blood is returned to the body via the internal space of the outlet header 1a, and the harmful substances discharged into the internal space 9 of the outer cylinder 3 are transported by the dialysate 11 introduced from the inlet tube 4. The debris is taken out to the outside via the discharge pipe 4a.

However, such conventional cylindrical blood processing apparatuses have the following problems.

That is, in FIG. 1, blood flowing into the interior from the cut surface 7 of the hollow fiber membrane 5 is caused by non-uniformity in the size of the cut surface,
The blood introduced from the blood introduction port 20 of the inlet side header does not necessarily become uniform due to the dynamic pressure distribution of the blood.

In particular, since the dynamic pressure of blood applied to the surface of the central part of the cut surface is greater than that of the surrounding area, the amount of blood flowing through the central hollow fiber membrane is larger than that of the surrounding hollow fiber membrane.

If non-uniform blood flow occurs between a large number of hollow fiber membranes, the dialysis performance or ultrafiltration rate of the hemodialysis device or hemofiltration device as a whole will decrease, and the When blood is returned, the blood return speed is different, which causes a phenomenon of blood remaining in the internal space of the hollow fiber membrane group at the outer periphery.

Particularly when long-term hemodialysis or long-term blood E-filtration is performed, blood clots occur in the internal space of the hollow fiber membrane where the amount of blood is small, and there are parts where blood flow stops.

The present invention has been made in view of the above circumstances, and its objects are to easily introduce the blood introduced into the header into the internal space of all the hollow fiber membranes, and to cut the hollow fiber membranes. The goal is to eliminate hemolysis (destruction of red blood cells) at the surface and blood clots that occur near the cut surface.

The present invention is characterized in that the inner diameter of the hollow fiber membrane at the cut surface of the fixed hollow fiber membrane is expanded, for example, into a trumpet shape, thereby enabling long-term hemodialysis and hemofiltration. This is a thread membrane blood processing device.

Hollow fibers targeted by the present invention include hollow fibers of cellulose fibers such as cuproammonium rayon, xantate rayon, cellulose acetate, and nitrocellulose;
Hollow holes in porous synthetic polymers such as polyvinyl alcohol hollow fibers, polymethyl methacrylate hollow fibers, polyvinyl chloride hollow fibers, polyacrylonitrile hollow fibers, polysulfone hollow fibers, polypeptide hollow fibers, collagen hollow fibers, and polycarbonate hollow fibers. It is a thread membrane.

The method for enlarging the cut surface of these hollow fiber membranes varies depending on the properties of the hollow fiber membrane, but generally, after fixing the hollow fiber membrane and exposing the cut surface, the hollow fiber membrane is expanded. The tip of the hollow fiber membrane is immersed in a polar swelling agent suitable for each hollow fiber material, and after confirming that the tip of the hollow fiber membrane has swelled, it is removed from the swelling agent and dried with a heat source to remove the swelling agent. By contracting the wall thickness of the hollow fiber membrane outward, the inner diameter of the hollow fiber membrane structure can be expanded into a trumpet shape.

Alternatively, the inner diameter may be expanded by shrinking the wall thickness of the hollow fiber membrane outward using only a direct heat source.

Various polar swelling agents can be used, such as water, alcohols, ketones, amines, ethers, ester compounds, dimethyl sulfoxide, dimethyl formamide, etc. However, substances that are easy to use include water, methanol, ethanol, Low boiling point alcohols such as propenol and isopropyl alcohol, ketone compounds such as acetone and methyl ethyl ketone, and ether compounds such as methyl ether and ethyl ether are most suitable.

Such a method in the present invention can be used for hollow fiber membranes of porous polymers or hollow fiber membranes of shrinkable materials.

In particular, when a hollow fiber membrane is treated with the treatment method of the present invention, the wall thickness of the hollow fiber membrane can be reduced to about 1/10 of that in its original state, although it depends on the degree of shrinkage of the hollow fiber membrane. can.

The present invention will be explained in more detail below with reference to the drawings.

FIG. 2 is an enlarged view of only a portion of the entrance side header of FIG. 1.

The cut surface of the hollow fiber membrane bundle is easy to see.

FIG. 3 shows an example of a cross section of the hollow fiber membrane shown in FIG. 2 with the inner diameter enlarged as in the present invention.

In this figure, the inner diameter tapers toward the cut surface.

As described above, in the blood processing device of the present invention, since the inner diameter is enlarged at the cut surface of the hollow fiber membrane, the resistance to the introduced blood at the end is small, and the flow is less likely to be disturbed. Since blood flows smoothly, non-uniformity in the amount of blood flowing into the hollow fiber membrane is also improved.

Next, in an example, we will compare the method of enlarging the pore diameter of the hollow fiber membrane at the cut surface of the hollow fiber membrane and the performance of a blood processing device filled with a hollow fiber membrane subjected to this treatment and a conventional blood processing device. show.

Example 1 2200 polyacrylonitrile hollow fiber membranes with an inner diameter of 300 μm and a membrane thickness of 50 μm were fixed to an outer cylinder 3 with a partition wall 6, and both ends were cut so that the cut surfaces of the hollow fiber membranes were exposed to the external surface. One end of the hollow fiber membrane was immersed in prepared water for about 5 m, and after a few minutes it was taken out of the water, and the outer cylinder 3 to which the hollow fiber membrane was fixed was shaken to remove most of the water, and the cut surface was By drying with hot air at about 80℃, the inner diameter at the cut surface of the hollow fiber membrane is expanded, and the inner diameter at the cut surface is 3.
A hollow fiber membrane with a pore size of 80μ was obtained.

The inner diameter of the other end was also enlarged by the same operation as described above.

Example 2 Even when ethanol was used instead of the water used in Example 1, the inner diameter at the cut surface of the hollow fiber membrane was expanded to 375μ by the same operation as described above.Example 3: The inner diameter was 250μ The same operation as in Example 1 was carried out using a cuproammonium rayon hollow fiber membrane having a membrane thickness of 30 μm.

The inner diameter of the hollow fiber membrane at the cut surface was expanded to 280μ.

Example 4 The hollow fiber membrane blood processing device obtained in Example 1 (hereinafter abbreviated as improved type) and the conventional blood processing device (hereinafter abbreviated as comparative example) were tested (polyacrylonitrile hollow membrane with an inner diameter of 300 μm). Fiber membrane used, 2200 hollow fiber membranes, effective membrane area 0.23 m, hollow fiber membrane filling rate 50%) and fresh blood (hematocrit value 35%, total protein concentration 9.2,
9/d! ') to trans membrane differential pressure (Trans Membrane pressure)
e Pressure) 25 mrn Hg s
Table 1 shows the results of measuring the amount of blood passing through the device, the amount of ultrafiltration, and the number of blood remaining after blood return after 3 hours of introducing the device under a differential pressure ΔPB of 25 mmHg at the entrance and exit of the device.

As can be seen from Table 1, in the blood processing device of the present invention, the amount of blood passing through and the amount of excess E exceeded three times that of the comparative example, and the number of remaining blood was approximately 1/10. Reduce to

In this way, by enlarging the inner diameter of the hollow fiber membranes at the cut plane of the hollow fiber membrane group, the performance of the device is further improved.

Therefore, the blood processing device of the present invention is sufficiently effective for various blood processing devices, and is particularly effective when a blood pump such as a wearable artificial kidney is not used.

[Brief explanation of drawings]

Fig. 1 is an overall view of the blood processing device, and Fig. 2 is an enlarged cross-sectional view of the header and hollow fiber membrane group. FIG. 3 is an enlarged view of the inner diameter of the hollow fiber membranes at a cross section of the hollow fiber membrane group of the present invention. In the figure, 1 and 1a are the inlet side header and the outlet side header, 3
is an outer cylinder, 4 and 4a are ports for introducing or discharging dialysate, 5 is a hollow fiber membrane, 7 is a cut surface of the hollow fiber membrane group, and 10,
10a shows blood introduced and blood discharged.

Claims (1)

[Claims] 1. A hollow fiber membrane type blood processing device using a hollow fiber membrane bundle, characterized in that the inner diameter of the hollow fiber membrane is enlarged only at the cut surface.