Air trap chamber

Abstract

This air trap chamber comprises a cylindrical chamber body having a blood inflow port (121) and outflow port (122). The chamber body has a large-diameter part (111), a small-diameter part (113) that has a smaller diameter than the large-diameter part (111) and that is provided on the outflow port (122) side, and an intermediate part (112) that is provided between the large-diameter part (111) and the small-diameter part (113) and that has a diameter that gradually changes. The inflow port (121) is provided, on the side surface of the intermediate part (112)-side end part of the small-diameter part (113), so as to extend in a direction tangential to the circumference of the small-diameter part (113).

Description

Technical Field

[0001] The present disclosure relates to an air trap chamber.

Background Art

[0002] For patients with reduced kidney function, artificial dialysis is performed by withdrawing blood, purifying it, and returning it. An extracorporeal circulation circuit for artificial dialysis is provided with an air trap chamber for removing air bubbles from the blood. The air trap chamber is cylindrical with a filter provided at the lower end, and the blood introduced from the inlet at the upper end flows out from the outlet at the lower end through the filter. By accumulating a certain amount of blood in the air trap chamber to form a blood layer, air bubbles in the blood layer can be discharged into the upper air layer.

[0003] Normal artificial dialysis is performed by making punctures at two locations and securing two routes for blood withdrawal and blood return. However, depending on the condition of the shunt, etc., it may be possible to make a puncture at only one location. In such a case, the single-needle dialysis method is used. In the case of the single-needle dialysis method, a puncture needle having a branch is connected to the blood withdrawal side line and the blood return side line of the extracorporeal circulation circuit. Blood withdrawal and purification are performed with the blood return side line closed, and when a predetermined amount of blood withdrawal and purification are completed, the blood withdrawal side line is closed and the purified blood is returned from the blood return side line. The operations of blood withdrawal and blood return are repeated every few seconds.

[0004] Similar to the extracorporeal circulation circuit with punctures at two normal locations, an air trap chamber is also provided in the extracorporeal circulation circuit for the single-needle dialysis method. In the case of the single-needle dialysis method, since blood is not returned during blood withdrawal, blood continues to accumulate in the air trap chamber. For this reason, an air trap chamber having a larger diameter and a larger internal volume than a normal hemodialysis circuit is used in the extracorporeal circulation circuit for the single-needle dialysis method (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Special Publication No. 4-50022 [Overview of the project] [Problems that the invention aims to solve]

[0006] Dialysis monitoring devices are required to support not only the standard double-needle dialysis method but also the single-needle dialysis method. Therefore, dialysis monitoring devices are equipped with separate holders for securing the air trap chamber used in double-needle dialysis and for securing the larger diameter air trap chamber used in single-needle dialysis, which contributes to the overall size of the device.

[0007] In the case of single-needle dialysis, the pump operates to store the blood purified by the blood purifier in the chamber. Once storage is complete, the pump stops, air is sent out from the top of the chamber, and the stored blood returns to the patient. When the liquid level drops to near the liquid level sensor, the air stops, and the storage process resumes. This process is repeated to perform dialysis, but because the liquid level fluctuates up and down periodically, there is a risk of foaming or hemolysis occurring when the blood flowing in from the blood inlet collides with the liquid level.

[0008] In both standard double-needle dialysis and single-needle dialysis, fluid replacement and medication administration may be performed on the venous side. When mixing replacement fluids or other medications with blood in the air trap chamber, there is a problem in that the medication collides with the blood surface, creating air bubbles that can be trapped. Furthermore, while it is desirable for the mixed medication to mix quickly and uniformly with the blood, problems can arise in that the blood and medication do not mix quickly enough within the air trap chamber.

[0009] Furthermore, the chamber used for single-needle dialysis, which temporarily stores purified blood, is large, which can cause problems such as hindering the routing of line tubes depending on the port placement, or getting in the way during drug administration procedures.

[0010] The objective of this disclosure is to solve at least one of these problems and enable the realization of a highly functional air trap chamber. [Means for solving the problem]

[0011] A first aspect of the air trap chamber of the present disclosure comprises a cylindrical chamber body having a blood inlet port and a blood outlet port, the chamber body having a large diameter portion, a small diameter portion having a smaller diameter than the large diameter portion and provided on the outlet port side, and an intermediate portion provided between the large diameter portion and the small diameter portion and having a gradually changing diameter, the inlet port is provided on the side surface of the end of the intermediate portion side of the small diameter portion so as to extend in the tangential direction of the circumference of the small diameter portion.

[0012] In the first embodiment of the air trap chamber, the chamber body has a large-diameter section and a small-diameter section that is smaller in diameter than the large-diameter section and located on the outlet port side. This ensures sufficient chamber volume. Furthermore, since the inlet port is positioned to extend tangentially to the circumference of the small-diameter section, collision between the blood and the liquid surface is avoided, making it less likely for the blood to foam or lyse. In addition, the blood flowing in from the inlet port flows along the side of the chamber, creating a swirling flow. Because the inlet port is located in the small-diameter section, it is easy to maintain the swirling flow even when the liquid level rises and falls, and in combination with the vertical movement of the liquid level, the entire chamber can be efficiently agitated.

[0013] A second embodiment of the air trap chamber comprises a cylindrical chamber body having a blood inlet port and a blood outlet port, the chamber body having a large diameter section, a smaller diameter section smaller than the large diameter section and located on the outlet port side, and an intermediate section between the large diameter section and the small diameter section, the diameter of which gradually changes, the inner diameter of the large diameter section being 1.5 times or more and 3 times or less the inner diameter of the small diameter section, and the length of the large diameter section being 20% ​​or more and 70% or less the length of the small diameter section.

[0014] A second embodiment of the air trap chamber allows for a reduction in the diameter of the small section and a shortened overall length while maintaining the chamber's capacity, by making the inner diameter of the large section 1.5 times or more and 3 times or less than the inner diameter of the small section, and the length of the large section 20% or more and 70% or less than the length of the small section. This makes it easy to attach to a dialysis monitoring device.

[0015] A third embodiment of the air trap chamber comprises a cylindrical chamber body having a blood inlet port and a blood outlet port, wherein the chamber body has a large diameter section, a smaller diameter section located on the outlet port side which is smaller in diameter than the large diameter section, and an intermediate section located between the large diameter section and the small diameter section whose diameter gradually changes, and the volume of the large diameter section is 30% or more and 70% or less of the volume of the chamber body.

[0016] In a third embodiment of the air trap chamber, the chamber body has a large-diameter section and a small-diameter section that is smaller in diameter than the large-diameter section and located on the outlet port side, with the volume of the large-diameter section being 30% to 70% of the volume of the chamber body. Therefore, while ensuring the chamber capacity, the diameter of the small-diameter section can be reduced, and the overall length of the chamber can be shortened, making it easy to attach to a dialysis monitoring device.

[0017] In the air trap chamber of this disclosure, the large-diameter section has a fluid intake port, and the inlet port is located above the small-diameter section. Since the small-diameter section and the large-diameter section are separated by an intermediate section, bubbles generated by the collision of the fluid flowing in from the large-diameter section with the liquid surface are less likely to reach below the intermediate section. Furthermore, if the inlet port is located in the intermediate section, the blood flow may rush up along the inner surface of the intermediate section, and in combination with the vertically moving liquid surface, this may cause the liquid surface to become wavy. However, by having the inlet port in the small-diameter section, the occurrence of such a situation can be reduced. In addition, by having the inlet port located above the small-diameter section, the medication or fluid flowing in from the fluid intake port mixes more easily with the blood flow, making it easier to return the mixed solution to the patient.

[0018] In the air trap chamber of this disclosure, the chamber body has a first member that constitutes at least a part of the small diameter section, and a second member that includes a large diameter section, an intermediate section, and an inlet port, wherein the first member may be more flexible than the second member. With this configuration, the inner surfaces of the large diameter section, intermediate section, and the upper side of the small diameter section, which are easily contacted by the vertically moving liquid surface, can be made smooth without steps, thereby reducing the likelihood of thrombus formation. Furthermore, because the first member is more flexible than the second member, damage is less likely to occur when removing air bubbles by tapping with forceps or the like during priming. When the small diameter section is used as the attachment part, the flexibility of the small diameter section that is attached to the dialysis monitoring device can be ensured while ensuring the overall strength of the chamber, making deformation less likely even when blood is stored inside the chamber.

[0019] In the air trap chamber of this disclosure, the chamber body may have ribs formed on its outer surface over at least a portion of the intermediate and large-diameter sections. This configuration reduces deformation of the large-diameter section and the intermediate section, even when blood is stored in the large-diameter section.

[0020] A fourth aspect of the air trap chamber of the present disclosure comprises a cylindrical chamber body having a blood inlet port, an outlet port, and a fluid inlet port, wherein the chamber body has a first space and a second space located on the outlet port side of the first space, the first space being larger in diameter than the second space, the inlet of the fluid inlet port being located in the first space, the inlet of the blood inlet port being located in the second space, and the blood flowing in from the inlet port and the fluid flowing in from the fluid inlet port being guided to swirl in a first direction along the inner wall surface of the chamber body.

[0021] In a fourth embodiment of the air trap chamber, the blood flowing in from the inlet port and the liquid flowing in from the fluid outlet port are guided to swirl in a first direction along the inner wall surface of the chamber body. As a result, turbulence is less likely to occur within the chamber body, the blood and liquid are mixed quickly and uniformly, and the generation of air bubbles and the entrapment of any bubbles that do occur are less likely to occur. Furthermore, since the inlet of the fluid outlet port is located in the first space and the inlet of the blood inlet port is located in the second space, a layer of liquid introduced from the fluid outlet is easily formed on top of the layer of blood, making it easy to create a condition in which the blood does not come into direct contact with the air.

[0022] A fifth aspect of the air trap chamber of the present disclosure comprises a cylindrical chamber body having a blood inlet port, a blood outlet port, and a fluid port, wherein the inlet port is provided on the side of the chamber body so as to extend tangentially to the circumference of the chamber body, and the fluid port has a fluid tube with a closed bottom and a side opening that protrudes into the chamber body from the top plate of the chamber body, and the blood flowing in from the inlet port and the fluid flowing in from the fluid port are guided to swirl in a first direction along the inner wall surface of the chamber body.

[0023] In a fifth aspect of the air trap chamber, the side opening provided in the liquid guide cylinder opens on the downstream side of the blood flow, so the liquid introduced from the liquid guide port flows in the same direction as the blood flow. Therefore, it is difficult for turbulent flow to occur in the chamber body, and the blood and the liquid can be quickly and uniformly mixed, and the generation of bubbles and the entrainment of the generated bubbles can be made difficult to occur.

[0024] In a fifth aspect of the air trap chamber, the angle formed by the side opening and the inner wall surface of the chamber body can be made smaller than 90°. With such a configuration, the liquid flowing in from the liquid guide port can be smoothly guided by the inner wall surface of the chamber body, and it is easy to form a swirling flow.

[0025] A sixth aspect of the air trap chamber of the present disclosure includes a cylindrical chamber body having a blood inlet port, an outlet port, a liquid guide port, and a pressure measurement port. The chamber body has a large diameter portion, a small diameter portion provided on the outlet port side and having a smaller diameter than the large diameter portion, and an intermediate portion provided between the large diameter portion and the small diameter portion and having a gradually changing diameter. The inlet port is provided to protrude along the tangential direction of the circumference of the small diameter portion. The liquid guide port and the pressure measurement port are formed on the top plate portion of the chamber body. When the top plate portion is viewed in plan, the distance between the axis of the liquid guide port and the axis of the inlet port is larger than the distance between the axis of the pressure measurement port and the axis of the inlet port. The pressure measurement port is formed at a position shifted in the direction in which the inlet port protrudes from the line connecting the inlet port and the liquid guide port between the inlet port and the liquid guide port on the top surface.

[0026] In the sixth aspect of the air trap chamber, when the top plate portion is viewed in plan view, the distance between the axis of the liquid guide port and the axis of the inflow port is greater than the distance between the axis of the pressure measurement port and the axis of the inflow port. Therefore, when the inflow port is arranged on the back side of the dialysis monitoring device so that the line connected to the blood purification device does not get in the way, the liquid guide port is on the front side of the pressure measurement port. For this reason, it becomes easier for the user to perform the operation of administering the chemical solution using the liquid guide port. Further, since the pressure measurement port is provided at a position shifted in the direction in which the inflow port protrudes from the line connecting the inflow port and the liquid guide port between the inflow port and the liquid guide port on the top surface, it is easy to connect the pressure measurement line attached to the pressure measurement port to the dialysis monitoring device, and the handling of the pressure measurement line becomes easy.

Effect of the Invention

[0027] According to the air trap chamber of the present disclosure, it is possible to achieve at least one of corresponding to the single-needle dialysis method without complicating the dialysis monitoring device, reducing foaming during the introduction of the chemical solution, and promoting the mixing of blood and the chemical solution.

Brief Description of the Drawings

[0028] [Figure 1] It is a figure which shows an example of the layout of the dialysis monitoring device equipped with the extracorporeal circulation circuit which has the air trap chamber which concerns on one Embodiment. [Figure 2] It is a perspective view which shows the air trap chamber which concerns on one Embodiment. [Figure 3] It is a side view which shows the air trap chamber which concerns on one Embodiment. [Figure 4] It is a sectional view taken along the line IV-IV of FIG. 3. [Figure 5] It is a side view which shows an intermediate cap part. [Figure 6] It is a sectional view taken along the line VI-VI of FIG. 5. [Figure 7] It is a sectional view taken along the line VII-VII of FIG. 5. [Figure 8] It is a side view which shows an upper end cap part. [Figure 9] This is a bottom view showing the upper cap portion. [Figure 10] This is a cross-sectional view showing a magnified view of the inflow port at the upper end cap. [Figure 11] This figure shows an example of a dialysis monitoring device layout with an extracorporeal circulation circuit for double needles. [Figure 12] This is a plan view showing a modified configuration of the ports. [Modes for carrying out the invention]

[0029] The air trap chamber 100 of this disclosure is an air trap chamber that can be used in a blood circuit for single-needle dialysis and is attached to a dialysis monitoring device 400, for example, as shown in Figure 1. The air trap chamber 100 is held on the dialysis monitoring device 400 by holders 312 and 313 provided on the side of the dialysis monitoring device 400. Holder 312 holds the air trap chamber 100 by clamping it from the side. It also has a liquid level sensor that can monitor the liquid level in the air trap chamber 100 to prevent it from becoming too low. Holder 313 supports the lower end of the air trap chamber 100 and maintains a constant relative position between the air trap chamber 100 and the liquid level sensor, ensuring that liquid level monitoring is performed correctly. Furthermore, around the part of the dialysis monitoring device 400 to which the air trap chamber 100 is attached, there are a pump 300 to which the blood withdrawal line 202 is attached, a component sensor 311 for analyzing the components of the blood flowing through line 202, a clamp section 314 for opening and closing lines 202 and 204, and multiple ports 321 for supplying dialysate and draining waste fluid. If the blood withdrawal line 202 can be sufficiently closed by stopping the pump 300, the clamp section 314 may be configured to open and close only the blood return line 202. In addition, sensors for detecting air bubbles in the line or blood leaks may be provided on the clamp section 314.

[0030] In single-needle dialysis, the pump 300 withdraws blood with the return line 204 closed by the clamp 314 and sends the blood to the hemodialyzer. The blood purified by the hemodialyzer flows into the air trap chamber 100 and is stored there. Next, the blood withdrawal line 202 is closed and the return line 204 is opened, and the purified blood in the air trap chamber 100 is returned to the patient's body. Depending on the flow rate, this process is repeated every few seconds to tens of seconds.

[0031] As shown in Figures 2 to 10, the air trap chamber 100 has a cylindrical chamber body 101 and a trap filter 141 provided inside it. The chamber body 101 is composed of a first member 132, a lower end cap portion 131 connected to the lower end of the first member 132, and a second member 133 and an upper end cap portion 134 connected to the upper end. The second member 133 has a small diameter portion 133C to which the first member 132 is connected, and a large diameter portion 133A to which the upper end cap portion 134 is connected, and a gradually decreasing diameter portion 133B is provided between the large diameter portion 133A and the small diameter portion 133C.

[0032] The small-diameter portion 133C is provided with an inlet port 121 through which the inlet line 203 is connected and blood flows in. The upper end cap portion 134 has a connecting portion 134A that fits onto the second member 133, a side wall portion 134B, and a top plate portion 134C, on which ports 123 and 124 are provided. The lower end cap portion 131 has an outlet port 122 at its lower end to which the blood return line 204 is connected, and a trap filter 141 is fixed inside the lower end cap portion 131. Blood that flows into the chamber from the inlet port 121 passes through the trap filter 141 and flows out from the outlet port 122.

[0033] The large-diameter portion 111 is formed by the large-diameter portion 133A and the upper end cap portion 134 of the second member 133, the small-diameter portion 113 is formed by the small-diameter portion 133C of the second member 133, the first member 132, and the upper part of the lower end cap portion 131, and the intermediate portion 112 is formed by the reduced-diameter portion 133B of the second member 133. In this disclosure, the large-diameter portion 111 and the intermediate portion 112 are referred to as the first space, and the small-diameter portion 113 on the outlet port side of the first space is referred to as the second space.

[0034] The outer and inner diameters of the small-diameter section 113 are approximately equal to the outer and inner diameters of the air trap chamber of a blood circuit used in a normal hemodialysis method in which blood withdrawal and return are performed simultaneously by puncturing at two locations. In the dialysis monitoring device 400, the liquid level in the chamber is monitored by attaching it to a holder 312 on which a liquid level sensor is provided so as to sandwich the air trap chamber. The holder 312 is equipped with a liquid level sensor for controlling the liquid level during priming and a liquid level sensor for monitoring the liquid level in the air trap chamber in the single-needle method.

[0035] On the other hand, in the case of single-needle dialysis, the volume required for the air trap chamber to retain blood during blood withdrawal is about 1.5 to 3 times that of the conventional hemodialysis method. If the inner and outer diameters of the entire air trap chamber are the same as those of the conventional double-needle hemodialysis method, the length of the air trap chamber becomes very long. The air trap chamber 100 of this embodiment has a large-diameter section 111 with an inner diameter larger than the small-diameter section 113. Therefore, it is possible to increase the volume while keeping the length of the air trap chamber down.

[0036] The inner diameter of the large-diameter section 111 can be set according to the required chamber volume, but from the viewpoint of increasing the volume while keeping the length down, it is preferably 1.5 times or more, more preferably 2.2 times or more, the inner diameter of the small-diameter section 113. Also, from the viewpoint of preventing the large-diameter section 111 from becoming irregularly shaped and making it difficult to attach to the dialysis monitoring device, the inner diameter of the large-diameter section 111 is preferably 3 times or less, more preferably 2.8 times or less, the inner diameter of the small-diameter section 113. Also, the length of the large-diameter section 111 can be set according to the required chamber volume, but from the viewpoint of shortening the overall length of the chamber, it is preferably 70% or less, more preferably 50% or less, of the length of the small-diameter section 113. Also, from the viewpoint of securing volume, the length of the small-diameter section 113 is preferably 20% or more, more preferably 25% or more.

[0037] Furthermore, from the viewpoint of being able to store the blood necessary for blood withdrawal, the volume of the large-diameter portion 111 is preferably 30% or more, more preferably 40% or more, of the total volume of the chamber body 101. Also, from the viewpoint of ensuring the small-diameter portion 113 is available, the volume of the large-diameter portion 111 is preferably 70% or less, more preferably 60% or less, of the total volume of the chamber body 101.

[0038] In the air trap chamber 100 of this embodiment, the inlet port 121 is provided protruding from the side surface of the small-diameter portion 113 along the tangential direction of the circumference of the small-diameter portion 113. If the inlet port is provided vertically at the upper end of the chamber, the falling blood is likely to collide with the liquid surface, causing foaming or hemolysis. Also, if the port is provided vertically to the circumference of the small-diameter portion 113, there is a risk that the pulsating blood will forcefully spray out of the port and collide with the opposite wall, or fall vertically without flowing down the wall. By extending the inlet port 121 in the tangential direction of the circumference, it can move spirally within the chamber along the inner wall surface, making foaming and hemolysis less likely to occur.

[0039] In this embodiment, as shown in Figure 6, the radius (R) is slightly increased in the portion of the inner wall surface of the small-diameter section 133C where the inflow port 121 is connected, covering approximately one-quarter of the circumference. This configuration makes it less likely for hemolysis and other complications to occur. However, such a portion with a large radius (R) may be provided only as needed, or it may not be necessary.

[0040] In the air trap chamber 100 of this embodiment, the liquid level inside the chamber is located in the large-diameter section 111 above the inlet port 121 at the end of the blood withdrawal operation, and in the small-diameter section 113 below the inlet port 121 at the end of the blood return operation, i.e., at the start of the blood withdrawal operation. At this time, the distance between the liquid level and the top surface of the trap filter 141 is approximately 1 cm to 3 cm.

[0041] Blood flowing in through the inlet port 121 swirls along the tube wall towards the smaller diameter section 113. If the inlet port 121 is located in the larger diameter section 133A or the inclined smaller diameter section 133B, the blood flow passes through the section where the inclination angle changes, impairing the flow along the tube wall in that section and creating a flow that tends towards the center. This can cause air to be drawn in, leading to foaming and potentially causing blood clots. Also, if the inlet port 121 is located in the smaller diameter section 133B, a blood flow that tends to rush upward along the inner surface of the smaller diameter section 133B is likely to occur. This can cause the liquid surface to become turbulent due to the synergistic effect with the large vertical movement of the liquid surface during blood withdrawal and return. By locating the inlet port 121 in the smaller diameter section 133C, such a situation can be made less likely to occur.

[0042] In an air trap chamber into which blood is introduced from the side, it is preferable that the blood creates a swirling flow along the side of the chamber so that the entire chamber is efficiently agitated. By providing the inlet port 121 in the small-diameter section 133C, the swirling flow can be easily maintained even if the liquid level rises and falls significantly during blood withdrawal and blood return. Furthermore, while the liquid level in the chamber rises and falls during blood withdrawal and blood return, blood flows in from the inlet port 121 in a direction intersecting the vertical direction, so the blood flowing in from the inlet port 121 can efficiently agitate the entire chamber. In addition, because the reduced-diameter section 133B and the large-diameter section 133A are located above the inlet port 121, air bubbles generated by the collision of the replacement fluid or drug introduced from ports 123 and 124 on the top plate section 134C with the liquid surface are relatively unlikely to reach the small-diameter section 133C, while the position of the inlet port 121 above the small-diameter section 133C makes it easier to mix the replacement fluid or drug with the blood.

[0043] By providing the inlet port 121 in the small-diameter section 133C, compatibility with conventional air trap chambers for the double-needle method can be further enhanced. Figure 11 shows an example in which an extracorporeal circulation circuit for the double-needle method is attached to the dialysis monitoring device 400 in place of the air trap chamber 100 of this embodiment. The air trap chamber 102 for the double-needle method and the air trap chamber 100 of this embodiment have almost identical configurations in the portion below the inlet port 121. Therefore, both air trap chambers can be held by holders 312 and 313. Furthermore, monitoring of the liquid level inside the air trap chamber can be performed in the same way. In the air trap chamber 102 for the double-needle method, the inner diameter of the large-diameter section 111 is 1.5 times or more and 3 times or less the inner diameter of the small-diameter section 113, and the length of the large-diameter section 111 is 20% or more and 70% or less the length of the small-diameter section 113. Therefore, the holders 312 and 313 of the illustrated dialysis monitoring device 400 are designed to facilitate the installation of both the air trap chamber 100 of this embodiment and the air trap chamber for the double-needle method. However, the air trap chamber 100 of this embodiment is not limited to dialysis monitoring devices designed to accommodate both air trap chambers, but can also be installed in dialysis monitoring devices designed to accommodate only one of the single-needle or double-needle methods.

[0044] The position of the inlet port 121 is not particularly limited, but it is preferable to provide it near the upper end of the small-diameter portion 133C. Furthermore, it is preferable to provide the inlet port 121 below 50% and above 15% of the height of the second member 133. This ensures an overlapping portion between the first member 132 and the second member 133, thereby increasing the connection strength. Additionally, by ensuring a sufficiently high reduced-diameter portion 133B between the large-diameter portion 133A and the small-diameter portion 133C, a slope is ensured between the large-diameter portion 133A and the small-diameter portion 133C, preventing the formation of a steep step. This smooths blood flow and reduces the likelihood of air bubbles adhering to and remaining in the step.

[0045] In this embodiment, the small-diameter portion 113, which is formed by the first member 132 and the small-diameter portion 133C of the second member 133, has a straight shape with a constant inner diameter. However, the small-diameter portion 113 may have a tapered shape that gradually decreases in diameter towards the lower end, as long as the inclination is gentler than that of the intermediate portion 112. In this case, the small-diameter portion 113 may have multiple parts with different inclination angles. It may also have both a straight-shaped portion and a tapered-shaped portion.

[0046] In this embodiment, the second member 133 is provided with ribs 136 that are thicker than the other parts on the large-diameter portion 133A and the reduced-diameter portion 133B. By providing the ribs 136, the strength of the large-diameter portion 111 and the intermediate portion 112 is ensured, and the large-diameter portion 111 is less likely to deform when blood is stored. In addition, in this embodiment, the mold is designed so that the injection gate of the molding die is located on the rib 136 portion, and an injection gate mark 137 is created on the rib 136 portion. With this configuration, it is less likely to cause pinholes when the second member 133 is released from the mold. The ribs 136 can also be configured to extend to the small-diameter portion 133C side.

[0047] The port 123 provided at the upper end of the air trap chamber 100 in this embodiment is a liquid supply port for supplying chemical solution. As shown in Figures 8 to 10, the port 123 has a connection portion 123A that protrudes upward from the top plate portion 134C of the upper end cap portion 134 and to which a tube is connected, and a liquid supply cylinder 123B that protrudes into the large diameter portion 111. The liquid supply cylinder 123B is cylindrical with its upper end communicating with the connection portion 123A and its lower end closed. The port 123 is provided near the peripheral edge of the top plate portion 134C, and a part of the side surface of the liquid supply cylinder 123B is in contact with the inner wall surface of the side wall portion 134B. A part of the side surface of the liquid supply cylinder 123B is cut out to form a side opening 123a. Therefore, the liquid injected from the liquid intake port 123 does not fall from the lower end of the liquid intake tube 123B toward the liquid surface, but rather travels along the inner wall surface of the large-diameter section 111 from the side opening 123a to reach the liquid surface. This makes it less likely for the blood in the chamber to foam or lyse due to the falling liquid. Furthermore, when the top plate section 134C is viewed from the bottom (liquid intake tube 123B) side in a plan view, the angle θ1 between the direction in which the opening surface of the side opening 123a extends and the direction in which the line connecting the centers of the top plate section 134C and the liquid intake tube 123B extends can preferably be about -30° to 30°, more preferably about -10° to 10°. It is even more preferable to make θ1 greater than 0 so that the angle θ2 between the opening surface and the inner wall surface is less than 90°, as this makes it easier for the liquid discharged from the side opening 123a to move toward the inner wall surface of the side wall section 134B. In this embodiment, it is set to 5°. This ensures that the liquid discharged from the side opening 123a flows more reliably along the inner wall surface of the side wall portion 134B. It is preferable that the length of the opening surface of the side opening 123a, which is the chord of the liquid conduit 123B, is about 1 / 3 to 2 / 3 of the diameter of the liquid conduit 123B.

[0048] In this embodiment, the air trap chamber 100 is provided with a port 124 at its upper end in addition to port 123. Port 124 does not have a fluid guide tube protruding into the large-diameter section 111, and can be connected to lines for adjusting the fluid level, lines for measuring pressure, etc. The number of ports provided on the top plate section 134C is not limited, and there may be multiple fluid guide ports 123, or two or more ports 124 used for adjustment, etc. Furthermore, the fluid guide ports 123 may be provided as needed, or they may not be provided at all.

[0049] In this embodiment, there are two injection gate marks 138 on the surface of the top plate portion 134C. By using a mold that produces two injection gate marks 138 on the top plate portion 134C, it is possible to reduce the likelihood of pinholes occurring when releasing the upper end cap portion 134 from the mold.

[0050] In the air trap chamber 100 of this embodiment, it is preferable that the first member 132 has high flexibility so that it can be easily attached to the holders 312 and 313 of the dialysis monitoring device 400. On the other hand, in the air trap chamber 100 of this embodiment, blood is also stored in the large diameter section 111 when blood withdrawal is completed. For this reason, it is preferable that the second member 133, which is provided with the blood inflow port 121, has less flexibility than the first member 132 so that it does not deform significantly when blood is stored inside. Also, in order to remove air bubbles during priming, the air trap chamber 100 may be struck with forceps or the like, but if the flexibility of the first member 132 is higher than that of the second member 133, damage will be less likely to occur when struck with forceps or the like. Specifically, the first member 132 can be made relatively thin to increase its flexibility, and the second member 133 can be molded to be thicker than the first member 132 to decrease its flexibility. Furthermore, the first member 132 and the second member 133 can also be formed from modulus-adjustable materials such as polyvinyl chloride, styrene-based elastomer, and olefin-based elastomer. It is also possible to integrally mold the first member 132 and the second member 133 rather than forming them separately and assembling them. Integral molding eliminates the need for assembly, simplifying the manufacturing process. Additionally, the first member 132 and the lower end cap portion 131 can be integrally molded.

[0051] The trap filter 141 is provided to remove foreign matter and aggregates, and its shape, material, and mounting method are not particularly limited; the same type of trap filter used in a normal air trap chamber can be used.

[0052] As shown in Figure 12, blood flowing in from the inlet port 121 formed on the side of the air trap chamber 100 forms a blood flow 126 that swirls in a first direction along the inner wall of the air trap chamber 100. In this case, it is preferable to make the swirling direction of the drug solution flow 127 introduced from the port 123 having the fluid guide tube 123B coincide with the direction of the blood flow 126 to form the first direction. This makes it less likely to generate turbulence compared to when the drug solution is dropped vertically from the fluid guide tube 123B or when the drug solution is introduced so that it swirls in the opposite direction to the blood flow 126. As a result, the drug solution and blood can be mixed quickly and uniformly, and the generation of air bubbles and the entrainment of generated air bubbles can be reduced.

[0053] When viewed from the top plate portion 134C, if the inlet port 121 is positioned to protrude to the right from the upper end, the blood flow 126 will swirl counterclockwise. In this case, in order to align the swirling directions of the blood flow 126 and the drug solution flow 127, the side wall of the fluid guide cylinder 123B can be cut out to form a side opening 123a that includes the position furthest counterclockwise from the inlet port 121. Conversely, if the inlet port 121 is positioned to protrude to the left from the upper end, the blood flow 126 will swirl clockwise. For this reason, the side wall of the fluid guide cylinder 123B can be cut out to form a side opening 123a that includes the position furthest clockwise from the inlet port 121.

[0054] The angle θ2 between the opening surface of the side opening 123a and the inner wall surface of the chamber body 101 is preferably less than 90°. By making θ2 less than 90°, the liquid chemical discharged from the side opening 123a can be made to swirl along the inner wall surface of the air trap chamber 100. Note that θ2 is the angle between the tangent to the inner wall surface at the point where the extension of the opening surface intersects the inner wall surface of the chamber body 101 and the extension of the opening surface.

[0055] It is preferable that the side opening 123a of the drug solution introduction port 123 is formed above the blood inflow port 121. For example, the side opening 123a can be located within the first space, which is a combination of the large-diameter section 111 and the intermediate section 112, and the inflow port 121 can be located within the second space, which is the small-diameter section 113. When the replacement fluid is supplied above the blood inflow port, a simulation comparing how the replacement fluid mixes in a chamber with a large-diameter first space and a chamber with a constant diameter revealed that when the replacement fluid is supplied to the large-diameter first space, a layer of replacement fluid is more likely to form on top. This is presumed to be because the flow velocity of the replacement fluid flowing through the large-diameter section is slower than the flow velocity of the blood flowing through the small-diameter section. Therefore, by positioning the side opening 123a within the first space and the inflow port 121 within the second space, a layer of replacement fluid with a lower blood concentration is formed on top of the blood layer, creating a state where the blood is less likely to come into direct contact with the air layer inside the chamber. Furthermore, the fluid replacement layer includes not only a layer that contains no blood at all, but also a layer with a low blood concentration.

[0056] When the side opening 123a is located within the first space and flows into the small-diameter section 113 along the inner surface of the intermediate section 112, it is preferable to set the inclination angle of the inner surface of the intermediate section 112 to 60° or less, and more preferably to 50° or less. By reducing the inclination angle of the inner surface of the intermediate section 112, the speed at which the drug solution introduced from the port 123 collides with the blood flowing in from the inflow port 121 can be slowed, making it easier for a layer of replacement fluid to form on top of the blood layer. Also, if the inclination angle is too small, the large-diameter section 111 and the small-diameter section 113 will be connected in a stepped manner, so it is preferable to set the inclination angle to 20° or more, and more preferably to 30° or more.

[0057] Figure 12 shows an air trap chamber that has a large-diameter section above the inlet port 121 for storing blood and can be used in single-needle dialysis. However, even in an air trap chamber that does not have a large-diameter section above the inlet port 121, the drug solution and blood can be smoothly mixed by discharging the drug solution in a swirling motion along the swirling direction of the blood flow 126.

[0058] The port 123 for introducing liquids such as medicinal solutions is preferably located on the front side of the top plate 134C when in use, but it can be formed at any position on the top plate 134C. For example, although the maneuverability of the medicinal solution introduction line will be reduced, the port 123 for introducing liquids such as medicinal solutions may be formed in a position close to the inflow port 121 on the top plate (on the back side of the top plate when in use). Regardless of the position in which the port 123 is formed, it is preferable to form the side opening 123a so that the swirling direction of the blood flowing in from the inflow port 121 matches the swirling direction of the liquid flowing in from the port 123. Also, although the maneuverability of the medicinal solution introduction line will be reduced, the port for introducing medicinal solutions can also be formed on the side of the chamber body 101, similar to the inflow port 121. When the port for introducing medicinal solutions is formed on the side of the chamber body 101, it is also preferable to ensure that the swirling direction of the blood flow matches the swirling direction of the medicinal solution flow. Furthermore, it is preferable to form the drug solution introduction port above the blood inflow port 121.

[0059] When a chemical solution introduction port 123 is formed in the top plate portion 134C, its position is not particularly limited. However, as shown in Figure 12, when the top plate portion 134C is viewed from above, by arranging the ports such as the chemical solution introduction port 123 and the axis L1 of the inlet port 121 to be greater than the distance D2 between the pressure measurement port 124 and the axis L1 of the inlet port 121, access to the port 123 becomes easier and operability is improved. Specifically, in the example shown in Figure 12, the chemical solution introduction port 123 and the pressure measurement port 124 are positioned parallel to the direction in which the inlet port 121 extends and in front of a virtual center line passing through the center of the top plate portion, when the inlet port 121 is positioned towards the back, and the chemical solution introduction port 123 is positioned in front of the pressure measurement port 124. Furthermore, the distance between the inlet port 121 and the center of the top plate 134C is smaller than the distance between the drug solution introduction port 123 and the center of the top plate 134C, and the drug solution introduction port 123 and the inlet port 121 are positioned on opposite sides of the center of the top plate 134C.

[0060] When attaching the air trap chamber 100 to the dialysis monitoring device 400, if the inlet port 121 is positioned so that its protruding direction is nearly parallel to the wall surface of the dialysis monitoring device 400 and attached to the furthest side (back) of the dialysis monitoring device 400, so that the inlet line 203 does not get in the way, then port 123, which is farther from the axis L1 of the inlet port 121, will be closer to the front than port 124, which is closer. This makes it easier to perform operations such as supplying drug solution to port 123, improving operability. In order to increase the distance D1, it is preferable to form port 123 on the outer edge of the top plate portion 134C such that the direction connecting the connection position 121A of the inlet port 121 and the center of port 123 is preferably within a range of ±45°, more preferably within a range of ±15°, with respect to the direction connecting the connection position 121A of the inlet port 121 and the center of the top plate portion 134C.

[0061] It is preferable that the port 124 to which pressure measurement lines, etc., can be connected be formed between the inlet port 121 and port 123, and offset in the direction in which the inlet port 121 protrudes from the line connecting the inlet port 121 and port 123. By placing the port 124 for pressure measurement, etc., closer to the inlet port 121 than the drug solution introduction port 123, when the air trap chamber 100 is attached to the dialysis monitoring device 400, it can be placed closer to the dialysis monitoring device 400 than the drug solution introduction port 123, making it easier to connect the pressure measurement line to the dialysis monitoring device 400. In addition, the position of the transducer to which the pressure measurement line is connected in the dialysis monitoring device 400 is generally on the opposite side from the pump, as this is advantageous for miniaturizing the dialysis monitoring device 400. By forming port 124 at a position offset from the line connecting inlet port 121 and port 123 in the direction in which inlet port 121 protrudes, when the air trap chamber 100 is attached to the dialysis monitoring device 400, port 124 will be on the opposite side from the pump, making it easier to connect the pressure measurement line to the dialysis monitoring device 400.

[0062] While a pressure measurement line can be connected to port 124, other lines such as a liquid level adjustment line can also be connected. Figure 12 shows an example in which port 123, which has a fluid guide tube 123B for introducing a drug solution, and port 124, which does not have a fluid guide tube, are formed on the top plate portion 134C, but it is also possible to have a configuration in which other ports are formed on the top plate portion 134C. Furthermore, in the case of a dialysis monitoring device in which the pump is located on the right side and the blood purifier is located on the left side, an air trap chamber in which each port is mirror-symmetrical can be used.

[0063] An air trap chamber with a large diameter section for blood storage located above the inlet port can be used in single-needle dialysis, but it can also be used in conventional double-needle dialysis. [Industrial applicability]

[0064] The air trap chamber of this disclosure is highly functional and can be used in blood circuits for dialysis and the like. [Explanation of symbols]

[0065] 100 Air trap chamber 101A Chamber body 111 Large diameter section 112 Middle section 113 Small diameter section 121 Inflow Port 121A Connection location 122 Outflow Port 123 ports 123A Connection 123B Liquid guide cylinder 123a Side opening 124 ports 126 Blood flow 127 Chemical flow 131 Lower end cap section 132 First Member 133 Second Member 133A Large diameter section 133B Reduced diameter part 133C Small diameter part 134 Upper end cap section 134A Connecting section 134B Side wall part 134C Top panel 136 Ribs 137 Injection gate traces 138 Injection gate traces 141 Trap filter 202 Blood withdrawal line 203 Inflow Line 204 Blood return line 300 pumps 311 Component Sensor 312 Holder 313 Holder 314 Bubble Sensor 321 ports 400 Dialysis monitoring equipment

Claims

1. It comprises a cylindrical chamber body having a blood inlet port and a blood outlet port, The chamber body has a large diameter section, a small diameter section which is smaller in diameter than the large diameter section and is provided on the outlet port side, and an intermediate section which is provided between the large diameter section and the small diameter section and whose diameter gradually changes. The inlet port is provided on the side surface of the end of the small-diameter portion on the intermediate side, extending in the tangential direction of the circumference of the small-diameter portion, in an air trap chamber.

2. The inner diameter of the large diameter portion is 1.5 times or more and 3 times or less the inner diameter of the small diameter portion. The air trap chamber according to claim 1, wherein the length of the large-diameter portion is 20% or more and 70% or less of the length of the small-diameter portion.

3. The air trap chamber according to claim 1 or 2, wherein the volume of the large-diameter portion is 30% or more and 70% or less of the volume of the chamber body.

4. The large-diameter portion has a fluid guide port, The air trap chamber according to any one of claims 1 to 3, wherein the inlet port is located above the small diameter portion.

5. The chamber body comprises a first member that constitutes at least a part of the small diameter portion, and a second member that includes the large diameter portion, the intermediate portion, and the inlet port. The air trap chamber according to any one of claims 1 to 4, wherein the first member is more flexible than the second member.

6. The air trap chamber according to any one of claims 1 to 5, wherein the chamber body has ribs formed on its outer surface over at least a portion of the intermediate portion and the large-diameter portion.

7. The chamber body has a fluid port, The inlet of the fluid intake port is located within the first space consisting of the large-diameter section and the intermediate section. The inlet of the blood inflow port is located within the second space consisting of the small diameter portion. The air trap chamber according to any one of claims 1 to 6, wherein the blood flowing in from the inlet port and the liquid flowing in from the fluid intake port are guided to swirl in a first direction along the inner wall surface of the chamber body.

8. The chamber body has a fluid port, The fluid port has a fluid tube that protrudes from the top plate of the chamber body into the chamber body, with a closed bottom and a side opening. The air trap chamber according to any one of claims 1 to 6, wherein the blood flowing in from the inlet port and the liquid flowing in from the fluid intake port are guided to swirl in a first direction along the inner wall surface of the chamber body.

9. The air trap chamber according to claim 8, wherein the angle between the side opening and the inner wall surface of the chamber body is less than 90°.

10. The chamber body has a fluid intake port and a pressure measurement port, The fluid intake port and the pressure measurement port are formed on the top plate of the chamber body. The air trap chamber according to any one of claims 1 to 6, wherein, when the top plate is viewed in plan, the distance between the axis of the fluid intake port and the axis of the inlet port is greater than the distance between the axis of the pressure measuring port and the axis of the inlet port, and the pressure measuring port is formed at a position offset from the line connecting the inlet port and the fluid intake port in the direction in which the inlet port protrudes.

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