JPH0217181B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION This invention relates to a hollow fiber blood processing device having an improved blood inlet header. (Prior Art) Blood processing devices using hollow fibers have conventionally been widely used as hemodialysis devices, artificial liver devices, blood filtration devices, plasma separation devices, or artificial lung devices. As such a blood processing device (blood filtration device), a device in which blood inlet ports are provided at axially symmetrical positions as shown in FIG. 4 is usually used. In FIG. 4, reference numeral 1a denotes a blood inlet header with a circular cross section for guiding blood into the inside of the hollow fiber 5 and isolating it from the outside. be introduced. Reference numeral 1b denotes a blood outlet header having a circular cross section for collecting blood that has passed through the hollow fibers and leading it out from the blood outlet 20b. Reference numeral 2 designates a fixing cap for bringing the blood inlet and outlet headers 1a and 1b into close contact with the partition wall 6, which fixes the hollow fiber bundle, through the packing 12. The housing 3 is usually cylindrical and made of transparent, hard synthetic resin (polypropylene, polycarbonate, etc.), and its interior is filled with hundreds to tens of thousands of hollow fibers 5. The housing 3 is also provided with a filtrate outlet 4. A large number of hollow fibers 5 are packed in the housing 3, and both ends of the hollow fibers 5 are fixed liquid-tightly with partition walls 6 made of polyurethane resin or the like having excellent blood compatibility.
It communicates with the space provided in 1b. Blood is introduced into the device through the blood inlet port 20a of the blood inlet header 1a, and harmful substances in the blood are discharged into the housing 3 through the wall membrane of the hollow fibers. It is returned to the body via On the other hand, harmful substances discharged into the interior of the housing 3 are taken out from the outlet 4. Recently, a blood processing device has been proposed in which blood is introduced tangentially into a space provided in a blood inlet header in order to introduce blood uniformly into each hollow fiber (Japanese Patent Publication No. 60-5308, (Sho 57-86361, etc.) FIG. 5 shows an example of such a device, and common parts in the figure are given the same numbers as in FIG. 1.
In this device, blood is introduced into a blood inlet port 2 which opens tangentially from the outside to the inside of the blood inlet header 1a.
It is introduced from 0a and descends while turning along the blood guide path 10 provided in a spiral shape along the inner wall surface of the upper end of the space provided in the header, and reaches the outer periphery of the cut surface of the hollow fiber bundle. Then, it becomes a spiral flow toward the center and is introduced into each hollow fiber from the cut surface. (Problems to be Solved by the Invention) However, such conventional blood processing devices have the following drawbacks. There are various practical problems in the case of long-term use over several days, such as hemodialysis (non-hepadialysis or reduced hepadialysis), continuous hemofiltration (CAVH), and extracorporeal circulation pulmonary support (ECMO). That is, in the blood processing apparatus shown in FIG. 4, structurally,
Blood introduced from the blood inlet 20a first collides with the center of the end face of the hollow fiber, and then is dispersed into the hollow fiber at the outer periphery. Therefore, the speed of blood flowing through the space inside the header is high near the area immediately below the blood inlet, and decreases toward the periphery.
As a result, blood stagnation occurs within the space of the header, and blood stagnation occurs in the periphery of the space provided in the header.
Blood may become stagnant. As a result, its performance as a blood processing device deteriorates, and when blood is returned,
Because the blood return speed differs between the central and peripheral areas, residual blood occurs inside the hollow fibers near the peripheral areas or in areas where blood stagnates. On the other hand, in the device shown in FIG. 5, blood is guided from the tangential direction to the outer periphery that occupies a relatively large area on the cut surface of the hollow fiber, and then the thickness of the helical flow path gradually decreases. The speed of blood inflow into the blood fibers at the inner circumference is kept more uniform than in the device shown in FIG.
Moreover, the blood flow velocity parallel to the cut plane can also take a large value. However, the blood flow in the space provided in the header is not a fixed flow path, and although it takes a helical flow path, the blood flow itself is circular motion, so dense blood cell components etc. , blood does not reach the center, and if we look at the overall flow of blood within the header, the flow is rather slow in the center, causing blood stagnation, which causes thrombus formation.
In addition, depending on the distribution of the hollow fibers housed in the housing, the undulations of the cut surface of the hollow fibers, and the undulations of the contact surface of the header with blood, partial eddy flow, accompanying thrombus formation, and air bubbles may occur. There were problems such as stagnation of blood easily occurring, and the volume of blood filling increased because the header became bulky. (Means for Solving the Problems) Accordingly, an object of the present invention is to provide a blood inlet header which has less accumulation of air bubbles, less occurrence of thrombus, and less blood clot, and which does not cause blockage of hollow fibers even when used continuously for a long time. An object of the present invention is to provide a blood processing device having the following features. That is, the present invention includes a blood inlet header at one end;
This is a hollow fiber type blood processing device in which a large number of hollow fiber bundles are housed in a ring shape in a cylindrical housing having a blood outlet header at the other end, and a flat top portion is formed inside the blood inlet header. A conical port wall is provided, and a blood inlet opening tangentially toward the outside of the port wall is provided, and the flat top of the conical port wall is connected to a ring-shaped hollow fiber bundle. This is a hollow fiber type blood processing device characterized in that the cut surface is brought into contact with the central portion where no hollow fibers are present. (Function) The blood processing device of the present invention has a conical port wall with a flat top formed inside the blood inlet header, and the flat top has a hollow fiber bundle cut surface. Because the blood comes into contact with the non-existent center, the blood led from the blood inlet into the space provided in the header circulates around the space in a circular manner in the circumferential direction and reaches the cut surface of the hollow fiber bundle, that is, the hollow fiber bundle. be introduced inside. Since the top of the conical port wall is flat, blood will not flow into that area (usually the center of the header) and will not cause stagnation in the center. Also,
At this time, blood pressure is uniformly applied to each cut surface of the hollow fibers, so that blood is uniformly introduced into the interior of the hollow fibers. Therefore, it is presumed that stagnation that causes accumulation of air bubbles and thrombus formation within the open end surface of the hollow fiber bundle, inhibition of platelet adhesion, and occlusion of the hollow fibers can be eliminated. (Example) Next, an example of the blood processing apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a partial cross-sectional view of the apparatus of the present invention, and FIG. 2 is a cross-sectional view showing another example of the blood inlet header 1a, and common parts in the figures are designated by the same numbers as in FIG. 4. Further, FIG. 3 is an enlarged perspective view of the blood inlet header. The device shown in FIG. 1 is characterized by its structure centered around the header portion. In the apparatus of the present invention, blood introduced from the blood inlet 20a of the blood inlet header 1a is introduced from the tangential direction of the outer periphery of the space within the header. As shown in FIGS. 1 to 3, a conical port wall with a flattened top is provided inside the blood inlet header, and the flattened top 7 is formed into a ring-shaped hollow fiber. Since the blood comes into contact with the center of the cut surface of the bundle where no hollow fibers are present, the blood introduced into the header from the blood inlet 20a becomes a helical flow and an annular flow due to the inclination of the port wall, and flows around the inside of the port to reach the hollow fibers. be introduced internally. Therefore, blood is introduced into each hollow fiber almost uniformly. Further, it is preferable that the blood outlet header 1b is also provided with the blood outlet 20b in the tangential direction of the header, as in the case of the inlet header 1a, since this makes it possible to reduce the lengthwise dimension of the apparatus, thereby making it more compact. In this case, it is preferable not to provide a conical port wall inside the blood outlet header 16. Further, since the flattened top of the conical port wall formed inside the blood inlet port comes into contact with the cut surface of the hollow fiber bundle housed in the housing, the hollow fibers are arranged in a ring shape. It is necessary to prevent the presence of hollow fibers in the area where the flat top portion comes into contact. Next, the performance of the device of the present invention and the conventional device will be compared. As the device of the present invention, a blood inlet header having a conical port wall as shown in FIG. 1 was used. In addition, a blood outlet header without a conical port wall was used. On the other hand, devices shown in FIGS. 4 and 5 were used as conventional devices. (A polysulfone membrane with an inner diameter of 235 μm is used, the number of hollow fibers is 4300, and the effective membrane area is 0.5 m ² ) Fresh bovine blood (hematocrit value 38%, total protein concentration 6 g/dl) is used in each of the above blood processing devices, and the blood flow rate is 200 ml. A hemofiltration test was conducted under the conditions of 100 mmHg/min and a transmembrane pressure difference of 100 mmHg. Table 1 shows the results of measuring the amount of ultrafiltration after 8-hour hemofiltration and the number of blood remaining after blood return.

[Table] From the above results, it is clear that the device of the present invention has a larger amount of ultrafiltration and an extremely smaller number of residual blood tubes than the conventional device. Furthermore, as a result of visual observation, it was confirmed that in the blood processing apparatus of the present invention, the blood introduced into the header was almost uniformly introduced into each hollow fiber. Therefore, the blood processing device of the present invention can be used for extracorporeal circulation pulmonary support or continuous hemofiltration that is used continuously for a long time.
Alternatively, it is suitably used for reduced heparin dialysis. (Effects of the Invention) As described above, the blood processing device of the present invention includes a conical port wall with a flat top formed inside the blood inlet header, and the flat top is arranged in a ring shape. Since the cut surface of the hollow fiber bundle is brought into contact with the center part where no hollow fibers are present, the blood velocity parallel to the open end surface of the hollow fiber bundle can be suitably maintained. Such a structure can reduce the influence on the speed of blood inflow into the hollow fiber,
Therefore, in the blood processing device of the present invention, a substantially uniform inflow velocity is obtained, which strongly suppresses the accumulation of air bubbles in the header internal space and the generation of thrombi and blood clots, which is impossible with conventional devices. It is possible to use it continuously for long periods of time, and to perform non-hepatodialysis and reduced hepatodialysis.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view showing an example of the blood processing device of the present invention, FIG. 2 is a cross-sectional view of a header showing another embodiment, and FIG. 3 is a cross-sectional view of a header of one embodiment of the present invention. FIG. 4 is an enlarged perspective view of the part shape, and FIGS. 4 and 5 are partial cross-sectional views of a conventional blood processing apparatus. 1a, 1b...Blood inlet, outlet header, 2...
Fixed cap, 3... Housing, 4... Filtrate outlet, 5... Hollow fiber, 6... Partition wall, 7... Flat top, 8... Header internal space.

Claims (1)

[Claims] 1 A hollow fiber type blood processing device in which a large number of hollow fibers are housed in a ring shape in a cylindrical housing having a blood inlet header at one end and a blood outlet header at the other end, wherein A conical port wall having a flat top is provided, and a blood inlet opening tangentially toward the outside is provided at an end of the port wall, and the flat top of the conical port wall is provided with a blood inlet opening tangentially to the outside. A hollow fiber type blood processing device characterized in that the hollow fiber bundle cut surface arranged in a ring shape is brought into contact with the center part where no hollow fibers are present.