JP6728726B2 - Oxygenator with built-in filter - Google Patents

Description

The present invention relates to an artificial lung that exchanges gas with blood in an extracorporeal circulation. In particular, the present invention relates to an oxygenator with a built-in filter, which has a filter for capturing air bubbles or foreign matter mixed in or generated in blood.

In cardiac surgery, an artificial cardiopulmonary circuit for extracorporeal blood circulation is used to arrest the patient's heart and substitute respiratory and blood circulation functions during that period. The artificial lung, which constitutes the main part of the artificial heart-lung circuit, provides a gas exchange function for blood (a function of supplying oxygen to the blood and discharging carbon dioxide) in place of the lungs of the patient. As a structure of an artificial lung, a hollow fiber membrane type artificial lung is widely used.

The hollow fiber membrane-type artificial lung is configured so that a gas containing oxygen and blood are caused to flow with a porous hollow fiber membrane interposed, and gas exchange is performed between the blood and the gas. That is, a hollow fiber membrane bundle in which a large number of hollow fiber membranes are laminated is arranged on the blood flow path in the housing in which blood flows. Blood is passed across the hollow fiber membrane bundle while flowing an oxygen-containing gas through the hollow fiber membrane. When blood passes through the gaps between the hollow fiber membranes, gas exchange, that is, oxygen addition and decarboxylation gas, is performed through the hollow fiber membranes.

Prior to circulating blood in the artificial heart-lung circuit, a priming solution such as physiological saline is circulated in order to remove air bubbles and foreign substances from the blood circulation circuit and to adapt the liquid to the hollow fiber membrane of the artificial lung. Priming is applied to the circuit. In priming, it is necessary to remove air bubbles and foreign matters in the priming liquid. Further, even after priming, foreign matter such as thrombus may be mixed in the blood in the blood circulation. Therefore, a blood filter device is often incorporated in the artificial heart-lung circuit in order to remove air bubbles and foreign substances.

In a blood filter device, generally, a filter formed by folding or winding a sheet-shaped filter medium is arranged on a blood flow path inside a housing. When blood passes through the filter, air bubbles and foreign substances are captured and discharged.

In order to simplify the artificial heart-lung circuit and reduce the amount of blood filled in the blood circulation circuit, a filter-equipped artificial lung that is built in and integrated with the artificial lung without separately providing a blood filter device is known. ..

FIG. 7 is a cross-sectional view showing a conventional hollow fiber membrane-type artificial lung 100 having a filter built therein (see Patent Document 1). The artificial lung 100 includes a gas exchange section 110 formed in a housing 111 and a heat exchange section 120 formed in a heat exchanger housing 121. The blood B flows in through the blood introduction port 101, sequentially passes through the heat exchanger 120 and the gas exchange section 110, and flows out through the blood extraction port 102.

A heat medium inflow port 122 and a heat medium outflow port (invisible to the heat medium inflow port 122 in FIG. 7) are provided at the lower end of the housing 121 of the heat exchange unit 120. Inside the housing 121, a bellows-type heat exchange body 125 having a tubular shape and a cylindrical heat medium chamber forming member (cylindrical wall) 126 arranged along the inner circumference of the heat exchange body 125 are installed. .. The heat medium that has flowed in from the heat medium inflow port 122 passes through the inside of the heat exchanger 125 and flows out from the heat medium outflow port. On the other hand, blood B flows into the housing 121 from the blood introduction port 101 and passes outside the heat exchanger 125. Heat is exchanged between the heat medium inside the heat exchanger 125 and the blood outside the heat exchanger 125.

The housing 111 of the gas exchange unit 110 is provided with a gas inflow port 112 in the upper part, and a gas outflow port 113 and an exhaust port 114 in the lower part. In the housing 111, a hollow fiber membrane bundle 115 and a bubble removing means (including a filter member 117 and an exhaust hollow fiber membrane layer 116) are housed. The upper and lower ends of the hollow fiber membranes forming the hollow fiber membrane bundle 115 are fixed by partition walls 118a and 118b made of potting material, respectively. Thus, a blood flow path that passes through the hollow fiber membrane bundle 115, the exhaust hollow fiber membrane layer 116, and the filter member 117 in order is formed between the partition walls 118a and 118b. The space above the partition 118a and the space below the partition 118b are divided by a partition 119a and a partition 119b, respectively.

The exhaust hollow fiber membrane layer 116 is configured by accumulating a large number of hollow fiber membranes. The filter member 117 is formed of a flat sheet-like member having a substantially rectangular shape, is provided in contact with the downstream surface of the exhaust hollow fiber membrane layer 116, and covers almost the entire surface. Air bubbles in the blood flowing through the blood flow path are captured by the filter member 117, permeate through the exhaust hollow fiber membrane layer 116, and are discharged to the outside of the housing 111 through the exhaust port 114. In this way, bubbles are prevented from flowing out of the blood outlet port 102.

JP, 2007-215992, A

The artificial lung 100 of FIG. 7 has a problem that when a large amount of air bubbles are mixed in blood, there are not a few air bubbles that pass through the filter member 117 and flow to the blood outlet port 102. This problem becomes more remarkable as the blood flow rate increases.

It is an object of the present invention to improve bubble trapping performance of a filter in a filter-containing type artificial lung.

The filter-equipped artificial lung of the present invention includes a housing in which a blood flow path is formed, a blood introduction port and a blood discharge port provided in the housing so that blood flows in the blood flow path, and a blood flow path in the blood flow path. A hollow fiber membrane bundle comprising a large number of hollow fiber membranes provided, and a gas inflow port and a gas outflow port provided in the housing so that a gas containing oxygen passes through the lumens of the plurality of hollow fiber membranes. And a filter that is provided in the blood flow path downstream of the blood flow with respect to the hollow fiber membrane bundle and that is configured to capture bubbles in the blood flowing through the blood flow path. The hollow fiber membrane bundle and the filter are separated by a spacer provided with an opening through which blood can pass.

In the present invention, since the hollow fiber membrane bundle and the filter are separated via the spacer provided with the opening, the flow velocity of blood is increased until the blood exits the hollow fiber membrane bundle and reaches the filter. descend. For this reason, gas-liquid separation in the filter is facilitated, and the bubble trapping performance of the filter can be improved.

FIG. 1 is a perspective view of an artificial lung according to an embodiment of the present invention as seen from above the front side. FIG. 2 is a perspective view of the artificial lung according to the embodiment of the present invention viewed from the lower rear side. FIG. 3 is a cross-sectional view of the artificial lung according to the embodiment of the present invention taken along the vertical plane. FIG. 4 is a sectional view taken along a horizontal plane of the artificial lung according to the embodiment of the present invention. FIG. 5A is a perspective view of a filter module in which a filter is held by a frame according to an embodiment of the present invention. FIG. 5B is a front view of the filter module. FIG. 6A is a perspective view of a spacer according to an exemplary embodiment of the present invention. FIG. 6B is a front view of the spacer. FIG. 7 is a cross-sectional view showing a conventional hollow fiber membrane-type artificial lung with a built-in filter.

In the above-mentioned artificial lung of the present invention, the distance between the hollow fiber membrane bundle and the filter is preferably 1 mm or more and 5 mm or less. When the distance is smaller than the above lower limit value, the degree of decrease in blood flow velocity between the hollow fiber membrane bundle and the filter is reduced, so that desired improvement in bubble trapping performance may not be obtained. On the other hand, if the distance is larger than the above upper limit, not only the air bubble trapping performance cannot be further improved, but also the blood filling amount of the artificial lung increases.

The aperture ratio of the spacer is preferably 50% or more. The high aperture ratio of the spacer is advantageous in improving the bubble trapping performance because the degree of decrease in the blood flow velocity between the hollow fiber membrane bundle and the filter increases.

A first flow path for exhausting from the first space on the spacer side with respect to the filter and a second flow path for exhausting from the second space on the blood outlet port side with respect to the filter are common. It may be provided in the exhaust pipe. In this case, it is preferable that the first flow path and the second flow path are independent of each other up to a position higher than the blood flow path. Providing the first flow path and the second flow path in a common exhaust pipe is advantageous for reducing the number of parts constituting the oxygenator and simplifying the exhaust line connected to the oxygenator. The fact that the first flow path and the second flow path are independent of each other up to a position higher than the blood flow path means that during blood circulation, the blood in one of the first space and the second space flows in the first flow path. It is advantageous to reduce the possibility of flowing through the channel and the second channel to the other.

The filter may be composed of a sheet-shaped filter medium provided with a plurality of pleats. In this case, it is preferable that the filter is arranged so that the pleats are parallel to the vertical direction. Providing a plurality of pleats on the filter increases the effective filter area, which is advantageous for improving bubble trapping performance. Arranging the filter so that the pleats are parallel to each other in the vertical direction is advantageous for discharging bubbles from the oxygenator to the outside because bubbles trapped by the filter can rise along the pleats.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments. However, it goes without saying that the present invention is not limited to the following embodiments. For convenience of description, each drawing referred to in the following description is a simplified view of main members constituting an embodiment of the present invention. Accordingly, the present invention may include any member not shown in the figures below. Further, within the scope of the present invention, each member shown in each of the following drawings may be changed or omitted.

FIG. 1 is a perspective view of an oxygenator with a built-in filter (hereinafter, simply referred to as “artificial lung”) 1 according to an embodiment of the present invention, as viewed from above the front side. FIG. 2 is a perspective view of the artificial lung 1 as seen from the lower rear side. FIG. 3 is a cross-sectional view of the artificial lung 1 taken along the vertical plane, and FIG. 4 is a cross-sectional view of the artificial lung 1 taken along the horizontal plane.

The artificial lung 1 includes a substantially rectangular parallelepiped housing 10 configured by combining a plurality of members. As shown in FIG. 3, a blood channel 11 having a circular cross section is formed in the housing 10 along the horizontal direction. The blood flow path 11 is defined by a seal portion 12 formed by using a seal material made of polyurethane resin, epoxy resin, or the like. A blood inlet port 15 and a blood outlet port 16 are provided on the rear wall and the front wall of the housing 10 corresponding to both ends of the blood flow path 11. The blood introducing port 15 and the blood deriving port 16 are arranged so as to open at the center of the circular cross section of the blood flow path 11. The blood B flows into the housing 10 through the blood introduction port 15, flows through the blood flow path 11, and flows out of the housing 10 through the blood discharge port 16.

A heat exchange unit 30, a gas exchange unit 40, and a filter unit 50 are arranged in this order in the housing 10 along the blood flow direction.

The heat exchange unit 30 includes a bundle of heat transfer tubes 31. The heat transfer tube 31 is made of stainless steel or the like. The heat transfer tube 31 is arranged in the horizontal direction on the blood flow path 11 so as to cross the blood flow path 11, and both end portions thereof are held by the seal portions 12 (see FIG. 4 ). A heat medium inflow port 35 and a heat medium outflow port 36 are provided in a region of the side wall of the housing 10 corresponding to the heat exchange section 30 (see FIGS. 2 and 4 ). The heat medium (cold water or hot water) flows into the heat exchange section 30 through the heat medium inflow port 35, passes through the heat transfer tube 31, and flows out of the heat exchange section 30 through the heat medium outflow port 36. The blood flowing through the blood flow path 11 passes through the gap between the adjacent heat transfer tubes 31 of the heat exchange section 30. At this time, heat is exchanged between the blood and the heat medium via the heat transfer tube 31.

The gas exchange section 40 includes a hollow fiber membrane bundle 42 formed by stacking a large number of hollow fiber membranes 41. As the hollow fiber membrane 41, for example, a porous hollow fiber membrane made of polypropylene can be used. The hollow fiber membrane 41 is vertically oriented and arranged on the blood flow passage 11 so as to cross the blood flow passage 11, and both ends thereof are held by the seal portions 12. A gas inflow port 45 and a gas outflow port 46 are provided in regions of the upper wall and the lower wall of the housing 10 corresponding to the gas exchange section 40. The oxygen-containing gas flows into the gas exchange section 40 through the gas inflow port 45, passes through the lumen of the hollow fiber membrane 41, and flows out of the gas exchange section 40 through the gas outflow port 46. The blood flowing through the blood flow path 11 passes through the gap between the adjacent hollow fiber membranes 41 of the gas exchange section 40. At this time, gas exchange is performed between the blood and the oxygen-containing gas via the hollow fiber membrane 41.

The filter unit 50 includes a filter 51 that functions as a filter medium. As the filter 51, for example, a mesh-shaped sheet material made of polyethylene terephthalate and having an opening of 40 μm can be used. As shown in FIG. 4, the filter 51 is formed with a plurality of regular pleats 52 formed by alternately repeating mountain folds and valley folds at regular intervals. In the present embodiment, in each pleat 52, the filter 51 is curved so as to have a substantially “U” shape, but it may be bent with a clear crease so as to have a substantially “V” shape. Good. The outer peripheral end of the filter 51 is held by a frame 53 having a substantially circular ring shape. The filter 51 is arranged in the blood flow path 11 along a plane perpendicular to the flow direction of blood flowing in the blood flow path 11 (horizontal direction in FIG. 3 ).

FIG. 5A is a perspective view of the filter module 55 in which the filter 51 is held by the frame 53, and FIG. 5B is a front view of the filter module 55 as seen from the downstream side (blood outlet port 16 side) of the blood flow. As best shown in FIG. 5B, a semi-cylindrical through hole 54 is formed in the upper portion of the frame 53.

The method of manufacturing the filter module 55 is arbitrary. For example, a molding die that can be divided into a first die and a second die can be used. The filter 51 is held in the first mold with the pleats 52 formed, the first mold and the second mold are overlapped so as to sandwich the filter 51, and the cavity is sealed between the first mold and the second mold. Fill and harden the material. After that, by separating the first mold and the second mold, it is possible to obtain the filter module 55 in which the frame 53 made of the cured sealing material holds the filter 51. The sealing material (that is, the material of the frame 53) is not limited, but thermosetting resin such as polyurethane can be used.

As shown in FIGS. 3 and 4, a spacer 60 is provided between the filter 51 and the hollow fiber membrane bundle 42.

6A is a perspective view of the spacer 60, and FIG. 6B is a front view thereof. The spacer 60 includes a circular outer frame 61, a plurality of circular frames 62 and a plurality of linear frames 63 arranged in the outer frame 61. The outer frame 61 and the plurality of circular frames 62 are concentrically arranged at a predetermined interval in the radial direction. The plurality of linear frames 63 extend radially from the center of the spacer 60 at equal angular intervals. The plurality of linear frames 63 connect the outer frame 63 and the plurality of circular frames 62. The circular frame 62 and the linear frame 63 have the same thickness (the dimension along the direction perpendicular to the paper surface of FIG. 6B). A plurality of substantially arc-shaped openings 65 surrounded by the circular frames 62 (or the outer frame 61 and the circular frame 62) adjacent to each other in the radial direction and the linear frames 63 adjacent to each other in the circumferential direction are provided inside the outer frame 61. Has been formed.

The spacer 60 has a mechanical strength that is not substantially deformed by the flow of blood or priming liquid. The material of the spacer 60 is not limited, but a resin material such as polyacetal, polycarbonate, polystyrene, polyamide, polypropylene, or rigid polyvinyl chloride can be used. The spacer 60 can be integrally manufactured as one component by injection molding or the like using these resin materials. Alternatively, part or all of the spacer 60 may be made of a metal material.

As shown in FIGS. 3 and 4, the frame 53 holding the filter 51 and the outer frame 61 of the spacer 60 are embedded in the sealing material 12 and held by the sealing material 12. A plurality of circular frames 62 and a plurality of linear frames 63 that form the spacer 60 are arranged in the blood flow path 11. Blood flowing through the blood flow path 11 passes through the plurality of openings 65 (see FIGS. 6A and 6B) provided in the spacer 60 and flows from the gas exchange unit 40 to the filter 51.

As shown in FIGS. 1 and 3, an exhaust port 57 is provided above the blood outlet port 16 of the housing 10. An exhaust pipe 58 is connected to the exhaust port 57. The exhaust pipe 58 is curved upward in a substantially arc shape, and a connector 59 is provided at its tip (end opposite to the exhaust port 57). The connector 59 is located higher than the exhaust port 57.

As shown in FIG. 3, the lumen of the exhaust pipe 58 is divided into a first flow path 58a and a second flow path 58b by a partition wall 58c. The first flow path 58a and the second flow path 58b each have a substantially semicircular cross section, and extend independently of each other over the entire length of the exhaust pipe 58. The first flow channel 58a is a space (first space 50a) in the blood flow channel 11 on the upstream side (spacer 60 side) of the filter 51 via the through hole 54 (see FIG. 5B) provided in the frame 53. ) Is in communication with. The second flow path 58b communicates with the space (second space 50b) in the blood flow path 11 on the downstream side (on the blood outlet port 16 side) of the filter 51. The connector 59 is not provided with a member corresponding to the partition wall 58c. Therefore, the first flow path 58a and the second flow path 58b in the exhaust pipe 58 are communicated with each other in the connector 59.

The operation of the artificial lung 1 of the present embodiment configured as above will be described.

The priming liquid or blood flows into the oxygenator 1 through the blood introduction port 15, passes through the blood flow path 11, and flows out of the oxygenator 1 through the blood discharge port 16. The heat exchange unit 30 adjusts the blood to a desired temperature, and the gas exchange unit 40 adds oxygen to the blood and decarboxylates the blood. In the filter unit 50, the filter 51 captures air bubbles and foreign matter in the priming liquid or blood.

As described above, in the conventional artificial lung 100 with a built-in filter (see FIG. 7), the flat sheet-shaped filter member 117 is provided in contact with the downstream surface of the exhaust hollow fiber membrane layer 116. .. Therefore, the blood reaches the filter member 117 immediately after passing through the gap between the hollow fiber membranes forming the exhaust hollow fiber membrane layer 116. In the exhaust hollow fiber membrane layer 116, a large number of hollow fiber membranes are arranged so as to cross the blood flow path. Therefore, the effective cross-sectional area of the blood channel (effective channel cross-sectional area) is reduced by the large number of hollow fiber membranes. Further, since the flat filter member 117 is in contact with the downstream surface of the exhaust hollow fiber membrane layer 116, a part of the filter member 117 is blocked by the hollow fiber membranes forming the exhaust hollow fiber membrane layer 116. Get lost. Therefore, the effective area of the filter member 117 (effective filter area) is reduced by the hollow fiber membrane in contact with the filter member 117. Therefore, the blood flows at a high speed through the space between the hollow fiber membranes of the exhaust hollow fiber membrane layer 116 having a reduced effective flow passage cross-sectional area, and collides with the filter member 117 having a reduced effective filter area at almost the same speed. .. On the upstream side of the filter member 117 (the exhaust hollow fiber membrane layer 116 side), the pressure of blood locally increases in the region of the filter member 117 that is not in contact with the hollow fiber membrane, so that some of the bubbles in the blood are The filter member 117 passes through the filter member 117 without being captured by the filter member 117. For this reason, in the conventional artificial lung 100, the air bubble trapping performance of the filter member 117 was insufficient.

On the other hand, in the artificial lung 1 of the present invention, the spacer 60 is provided between the hollow fiber membrane bundle 42 and the filter 51. The spacer 60 has a function of separating the hollow fiber membrane bundle 42 and the filter 51 from each other in the blood flow direction. For this reason, the blood that has flowed through the gaps between the hollow fiber membranes 41 forming the hollow fiber membrane bundle 42 at high speed is decelerated immediately after passing through the hollow fiber membrane bundle 42. Further, it takes some time for the blood thus decelerated to reach the filter 51 from the hollow fiber membrane bundle 42. For this reason, the bubbles in the blood rise in the blood before leaving the hollow fiber membrane bundle 42 and before reaching the filter 51. Some bubbles may reach the inner peripheral surface above the blood flow path 11 before reaching the filter 51. On the other hand, the bubbles that have reached the filter 51 have a relatively low flow velocity of blood, so that the filter 51 exerts its original bubble trapping function, traps the bubbles, and passes only blood. The bubbles captured by the filter 51 rise in the first space 50a. The bubbles that cannot pass through the filter 51 and remain in the first space 50a pass through the through holes 54 provided at the upper end of the first space 50a, and further pass through the first flow path 58a and the connector 59, It is discharged outside the artificial lung 1.

As described above, in the present invention, since the hollow fiber membrane bundle 42 and the filter 51 are separated by the spacer 6, the gas-liquid separation in the filter 51 is facilitated and the bubble capturing performance of the filter is improved. It is possible.

As shown in Examples described later, the effect of improving bubble trapping performance according to the present invention becomes more remarkable as the amount of blood flowing through the blood flow path 11 increases. It is considered that this is because the blood flow rate between the hollow fiber membrane bundle 42 and the filter 51 decreases more as the blood flow rate increases.

In the present invention, even if the spacer 60 is omitted and the hollow fiber membrane bundle 42 and the filter 51 are simply separated from each other, the blood is decelerated immediately after passing through the hollow fiber membrane 42, which is advantageous for improving the bubble trapping performance. It is possible. However, since the hollow fiber membranes 41 forming the hollow fiber membrane bundle 42 have flexibility, when the spacer 60 is omitted, the hollow fiber membranes 41 are curved and deformed so as to project toward the filter 51 side by the flow of blood. You can. For this reason, the distance between the hollow fiber membrane 41 and the filter 51 becomes narrow, and the degree of decrease in the blood flow velocity between the hollow fiber membrane bundle 42 and the filter 51 becomes small. Further, when the hollow fiber membrane 41 protruding toward the filter 51 contacts the filter 51, the effective filter area of the filter 51 is reduced. Therefore, the bubble trapping performance is not improved as expected. If the distance between the hollow fiber membrane bundle 42 and the filter 51 is increased, the bubble capturing performance is improved, but the volume of the entire blood flow path 11 is increased, so that the blood filling amount of the artificial lung 1 is increased. Therefore, it is important to arrange the spacer 60 on the downstream side of the hollow fiber membrane bundle 42 so that the deformation of the hollow fiber membrane 41 due to the blood flow is reduced.

The distance between the hollow fiber membrane bundle 42 and the filter 51 has an optimum effect depending on the configuration (for example, size and volume) of each part of the artificial lung and the use conditions (for example, blood flow velocity during extracorporeal circulation). Since the numerical value and the critical value slightly change, they can be appropriately adjusted in consideration of them. Generally, the lower limit of the distance between the hollow fiber membrane bundle 42 and the filter 51 is preferably 1 mm or more, more preferably 1.5 mm or more, and particularly preferably 2 mm or more. The upper limit of the distance is preferably 5 mm or less, more preferably 4.5 mm or less, and particularly preferably 4 mm or less. If the distance is too small, the degree of decrease in the blood flow velocity between the hollow fiber membrane bundle 42 and the filter 51 is reduced, and the desired improvement in bubble trapping performance cannot be obtained. If the above distance is too large, not only the air bubble trapping performance cannot be further improved, but also the blood filling amount of the artificial lung 1 will increase.

Since the plurality of pleats 52 are formed on the filter 51, the effective filter area through which blood can pass is expanded as compared with the flat sheet-shaped filter member 117 used in the conventional artificial lung 100 (see FIG. 7). This is advantageous for improving the bubble capturing performance.

Further, since the filter 51 is arranged in the blood flow path 11 so that the pleats 52 extend in the vertical direction, the air bubbles captured by the filter 51 rise along the pleats 52 in the first space 50a and penetrate. The holes 54 can be easily reached.

However, in the present invention, the shape of the filter that performs gas-liquid separation is not limited to the above embodiment. For example, like the conventional artificial lung 100 (see FIG. 7), it may have a flat sheet shape in which the pleats 52 are not formed.

In the present invention, the configuration of the spacer 60 is not limited to the above embodiment. It suffices that the hollow fiber membrane 41 constituting the hollow fiber membrane bundle 42 is provided with a frame for suppressing deformation and an opening through which blood can pass is formed. The shape of the frame does not need to be a combination of the circular frame 62 and the linear frame 63 as in the above embodiment, and may be, for example, a lattice shape, a honeycomb shape, or a blind shape.

The aperture ratio of the spacer 60 (the ratio of the total area of the openings 65 to the apparent area of the spacer 60, which is the total of the frames 62 and 63 and the openings 65), is as high as possible. Since the blood flow velocity is greatly reduced during the period, it is advantageous for improving the bubble trapping performance. Although the aperture ratio of the spacer 60 is not limited, it is preferably 50% or more, more preferably 60% or more, and particularly preferably 70% or more.

Although the operation when blood flows through the artificial lung 1 has been described above, the operation when the priming liquid flows through the artificial lung 1 is substantially the same as the above. The artificial lung 1 of the present invention is also excellent in the ability to trap air bubbles in the priming liquid.

When the priming liquid is first made to flow from the blood introduction port 15 to the artificial lung 1, the air existing in the blood flow path 11 is replaced with the priming liquid. When priming is performed, the second space 50b on the downstream side of the filter 51 is gradually filled with the priming liquid. When the liquid level of the priming liquid in the second space 50b becomes higher than the blood outlet port 16, a path for discharging air above the liquid surface to the outside is provided in the exhaust pipe 58 unless the artificial lung 1 is tilted. There is nothing else except the created second flow path 58b. That is, the second flow path 58b communicating with the second space 50b is particularly effective for discharging the air in the second space 50b to the outside during priming. Of course, when blood is flowing in the blood flow path 11, the second flow path 58b is also effective for discharging to the outside a few bubbles that have passed through the filter 51 and moved to the second space 50b. is there.

In the above embodiment, the first flow passage 58a communicating with the first space 50a and the second flow passage 58b communicating with the second space 50b are provided in the common exhaust pipe 58. The exhaust pipe 58 extends upward, and a connector 59 provided at the tip of the exhaust pipe 58 combines the first flow passage 58a and the second flow passage 58b into one exhaust flow passage. Since the first flow path 58a and the second flow path 58b are independent of each other up to a relatively high position, during blood circulation, one of the blood in the first space 50a and the second space 50b will be The possibility of flowing to the other through the flow path 58a and the second flow path 58b is low. The position where the first flow path 58a and the second flow path 58b communicate with each other (the position of the connector 59 in this embodiment) is preferably higher than the upper end of the blood flow path 11 and further the upper end of the blood flow path 11. It is preferably 3 cm or more, particularly 5 cm or more.

In the present invention, the first flow path 58a communicating with the first space 50a and the second flow path 58b communicating with the second space 50b can be provided in different exhaust pipes. However, providing the first flow path 58a and the second flow path 58b in the common exhaust pipe 58 as in the above-described embodiment reduces the number of parts constituting the artificial lung 1, and This is advantageous in simplifying the connected exhaust line.

In the artificial lung 1 shown in the above embodiment, the heat exchange section 30, the gas exchange section 40, and the filter section 50 are housed in the housing 10, but the artificial lung of the present invention is not limited to this. For example, the heat exchange unit 30 may be an artificial lung arranged outside the housing that houses the gas exchange unit 40 and the filter unit 50.

The artificial lung 1 (Example) according to the present invention in which the spacer 60 is interposed between the hollow fiber membrane bundle 42 and the filter 51 to separate them by 3 mm, the spacer 60 is omitted, and the hollow fiber membrane bundle 42 and the filter 51 are omitted. And an artificial lung (comparative example) arranged in contact with each other were prepared, and the bubble trapping performance of each artificial lung was evaluated.

In the experiment, a blood circulation circuit that circulates in the artificial lung was formed, and a predetermined amount of bubbles was injected into the circulating blood (heparinized cow blood) on the upstream side of the blood introduction port 15. The number of bubbles in the blood immediately before the blood introduction port 15 and immediately after the blood extraction port 16 were measured by a bubble counter. The difference (bubble reduction number) between the number of bubbles immediately before the blood introduction port 15 and the number of bubbles immediately after the blood extraction port 16 is obtained, and the ratio of the number of bubbles reduction to the number of bubbles immediately before the blood introduction port 15 is calculated. The bubble reduction rate (%) was calculated. The bubble trapping performance of the oxygenator was evaluated using the bubble reduction rate.

For each of the artificial lungs of Examples and Comparative Examples, the air bubble reduction rate was determined for three blood flow rates of 3.0 liters/minute, 5.0 liters/minute, and 7.0 liters/minute.

As a result, when the blood flow rate was 3.0 liters/minute, 5.0 liters/minute, or 7.0 liters/minute, the Example had a higher bubble reduction rate than the Comparative Example. The difference in the bubble reduction rate from the example increased as the blood flow rate increased. When the blood flow rate was 7.0 liters/minute, the air bubble reduction rate of the example was 2.8% higher than that of the comparative example.

From the above experiment, the artificial lung of the present invention in which the hollow fiber membrane bundle 42 and the filter 51 are separated by interposing the spacer 60 is advantageous in improving the bubble trapping performance, and It was confirmed that the artificial lung has a remarkable effect of improving the bubble trapping performance as the blood flow rate increases.

INDUSTRIAL APPLICABILITY The present invention can be preferably used as an artificial lung that constitutes an artificial heart-lung circuit for extracorporeal blood circulation. Since the artificial lung of the present invention has high bubble trapping performance regardless of the blood flow rate while suppressing an increase in blood filling amount, it can be widely used as a highly reliable and safe artificial lung. ..

1 Artificial lung (artificial lung with built-in filter)
10 Housing 11 Blood Channel 15 Blood Inlet Port 16 Blood Outlet Port 41 Hollow Fiber Membrane 42 Hollow Fiber Membrane Bundle 45 Gas Inlet Port 46 Gas Outlet Port 50a First Space 50b Second Space 51 Filter 52 Pleated 58 Filter Exhaust Pipe 58a 1 channel 58b 2nd channel 60 spacer 65 spacer opening

Claims (5)

A housing in which a blood channel is formed,
A blood inlet port and a blood outlet port provided in the housing so that blood flows in the blood flow path;
A hollow fiber membrane bundle consisting of a large number of hollow fiber membranes provided in the blood flow path,
A gas inflow port and a gas outflow port provided in the housing so that a gas containing oxygen passes through the lumens of the plurality of hollow fiber membranes;
A filter built-in type that is provided in the blood flow path, downstream of the flow of blood with respect to the hollow fiber membrane bundle, and is configured to capture bubbles in blood flowing in the blood flow path. An artificial lung,
The filter-containing artificial lung, wherein the hollow fiber membrane bundle and the filter are separated by a spacer provided with an opening through which blood can pass. The filter-containing artificial lung according to claim 1, wherein the distance between the hollow fiber membrane bundle and the filter is 1 mm or more and 5 mm or less. The filter-containing artificial lung according to claim 1 or 2, wherein the spacer has an aperture ratio of 50% or more. A first flow path for exhausting from the first space on the spacer side with respect to the filter and a second flow path for exhausting from the second space on the blood outlet port side with respect to the filter are common. The filter according to any one of claims 1 to 3, wherein the filter is provided in an exhaust pipe that operates, and the first flow path and the second flow path are independent of each other up to a position higher than the blood flow path. Built-in oxygenator. The said filter is comprised with the sheet-shaped filter medium in which the several pleat was provided, The said filter is arrange|positioned so that the said pleat may become parallel to a up-down direction. Oxygenator with a built-in filter.

Images