JP7501139B2 - Blood circuit pressure measuring device - Google Patents

Description

This disclosure relates to a blood circuit pressure measuring instrument, and in particular to a blood circuit pressure measuring instrument that separates a blood chamber and an air chamber using a flexible membrane and uses the displacement of the flexible membrane in response to the internal pressure of the blood chamber and the internal pressure of the air chamber to measure the pressure of the blood circuit.

Extracorporeal circulation therapy, in which blood is taken from the patient's body, treated externally using a blood treatment device such as a dialysis machine, and the treated blood is returned to the body, is comprised of a blood circuit that circulates the blood, a blood pump, and a blood treatment device.

Patent Document 1 discloses a pressure measurement unit that has a diaphragm membrane inside the housing that separates a blood chamber from an air chamber. With this pressure measurement unit, blood pressure can be indirectly measured by measuring the pressure in the air chamber. In addition, the diaphragm membrane prevents blood in the pressure measurement unit from coming into contact with air, reducing the risk of blood clots forming.

Publication No. WO2007056363

However, if blood stagnation occurs in the pressure measuring device, there is a possibility that a blood clot may occur. Therefore, there is a demand for a blood circuit pressure measuring device that is configured to prevent blood flow stagnation less easily than conventional technology.

The blood circuit pressure measuring device according to the present disclosure is a blood circuit pressure measuring device that is interposed in the blood circuit to measure the pressure of blood flowing through the blood circuit, and includes a housing including a lower housing having an inlet port through which blood is introduced and an outlet port through which blood is discharged, and an upper housing having a pressure measurement port, a flexible membrane that divides a chamber, which is the internal space of the housing, into a first chamber through which blood introduced from the inlet port and discharged from the outlet port passes, and a second chamber in which a fluid for pressure measurement is present, the flexible membrane displaces according to the internal pressure of the first chamber and the second chamber, and a blood flow stirring rib that extends in a direction intersecting the flow direction of blood flowing in from the inlet port.

According to the above configuration, the blood flow agitation ribs can add a left-right component to the blood flow flowing in from the inlet port, making it easier for the blood flow to reach the area near the periphery of the housing.

In the blood circuit pressure measuring device according to the present disclosure, it is preferable that the blood flow agitation rib has a front slope that extends obliquely from the bottom surface of the lower housing toward the upper housing and the outlet port.

With the above configuration, when blood flowing in from the inlet port collides with the blood flow agitation rib, the straight flow component is more likely to be maintained, preventing the blood's momentum from being lost. As a result, the fluidity of the blood in the blood chamber is improved, making it less likely for blood to stagnate.

In the blood circuit pressure measuring device according to the present disclosure, it is preferable that the blood flow agitation rib has a rear slope that extends obliquely from the top toward the lower housing side and the outlet port side.

The above configuration makes it difficult for blood to stagnate behind the blood flow agitation rib. In other words, it prevents the fluidity of the blood from being significantly impaired when the blood flow swirling due to the blood flow agitation rib flows behind the blood flow agitation rib.

In the blood circuit pressure measuring device according to the present disclosure, it is preferable that the length between the left and right side walls as viewed from the inlet port of the lower housing increases toward the upward direction.

With the above configuration, the blood flow that flows in the left-right direction can be efficiently converged by the blood flow agitation ribs, making it less likely for blood to stagnate at the periphery of the housing.

In the blood circuit pressure measuring device according to the present disclosure, it is preferable that the top of the blood flow agitation rib is located below the upper end of the inlet port.

The above configuration makes it difficult for blood to stagnate on the upper side of the blood flow agitation rib.

In the blood circuit pressure measuring device according to the present disclosure, it is preferable that the blood flow agitation rib extends in a direction inclined with respect to the flow direction of the blood flowing in from the inlet port.

The above configuration allows the length facing the blood flow to be increased, making it easier to generate the intended blood flow and less likely to cause unintended retention.

The blood circuit pressure measuring device according to the present disclosure is a blood circuit pressure measuring device that is disposed in the blood circuit to measure the pressure of blood flowing through the blood circuit, and includes a housing including a lower housing having an inlet port through which blood is introduced and an outlet port through which blood is discharged, and an upper housing having a pressure measurement port, a flexible membrane that divides a chamber, which is the internal space of the housing, into a first chamber through which blood introduced from the inlet port and discharged from the outlet port passes, and a second chamber in which a fluid for pressure measurement is present, the flexible membrane being displaced according to the internal pressure of the first chamber and the second chamber, and blood flow agitation ribs extending from the bottom surface of the lower housing toward the upper housing, and it is preferable that a plurality of blood flow agitation ribs are disposed in the flow direction of blood flowing in from the inlet port.

With the above configuration, the blood flow entering through the inlet port is easily changed by the multiple blood flow mixing ribs, allowing the blood flow to be mixed.

The blood circuit pressure measuring device configured as above is less likely to cause blood flow stagnation than conventional technology.

1 is a diagram showing an example of the configuration of a blood circuit to which a blood circuit pressure measuring instrument according to an embodiment is applied; FIG. 2 is a configuration diagram of one of three pressure measurement sites in FIG. 1 . FIG. 2 is a top view of the blood circuit pressure measuring instrument according to the embodiment. FIG. 4 is a front view corresponding to FIG. 3 . FIG. 4 is a bottom view corresponding to FIG. 3 . FIG. 4 is a side view corresponding to FIG. 3 . 5 is a cross-sectional view of the blood circuit pressure measuring instrument according to the embodiment taken along line BB in FIG. 4. 1 is a perspective view of a lower housing of a blood circuit pressure measuring instrument according to an embodiment, with an upper housing and a flexible membrane removed; FIG. 1 is a top view of a lower housing showing blood flow agitation ribs and blood (white arrows) in a blood circuit pressure measuring instrument according to an embodiment. FIG. 10 is a front cross-sectional view of the lower housing taken along line BB in FIG. 9. 10 is a side cross-sectional view of the lower housing taken along line CC of FIG. 9. FIG. 13 is a front view of a blood circuit pressure measuring instrument according to another embodiment. FIG. 13 is a bottom view corresponding to FIG. 12. FIG. 13 is a side view corresponding to FIG. 12. 13 is a cross-sectional view of the blood circuit pressure measuring instrument of FIG. 12 taken along line BB of FIG. 12. FIG. 13 is a perspective view of the lower housing of the blood circuit pressure measuring instrument of FIG. 12 with the upper housing and the flexible membrane removed. 13 is a top view of a lower housing showing a pair of blood flow agitating ribs and blood (white arrows) in the blood circuit pressure measuring instrument of FIG. 12. FIG. FIG. 18 is a front cross-sectional view of the lower housing corresponding to FIG. 17. FIG. 13 is a front view of a blood circuit pressure measuring instrument according to another embodiment. FIG. 20 is a bottom view corresponding to FIG. 19 . FIG. 20 is a perspective view of the lower housing of the blood circuit pressure measuring instrument of FIG. 19 with the upper housing and flexible membrane removed. 20 is a schematic diagram showing a pair of blood flow agitating ribs and blood (white arrows) in the blood circuit pressure measuring instrument of FIG. 19 using a top view of a lower housing. FIG. FIG. 13 is a front view of a conventional blood circuit pressure measuring instrument that does not have a blood flow agitation rib, as a comparative example. FIG. 24 is a bottom view corresponding to FIG. 23. FIG. 24 is a perspective view of the lower housing of the blood circuit pressure measuring instrument of FIG. 23 with the upper housing and flexible membrane removed. FIG. 13 is a diagram showing a method for calculating and displaying the age of air in a blood circuit pressure measuring instrument. FIG. 13 is a diagram showing the calculation results of the age of air in the blood circuit pressure measuring instrument of the embodiment. FIG. 13 is a diagram showing the calculation results of the age of air in a blood circuit pressure measuring instrument according to another embodiment. FIG. 13 is a diagram showing the calculation results of the age of air in a blood circuit pressure measuring instrument according to another embodiment. FIG. 1 is a diagram showing the calculation results of the age of air in a prior art blood circuit pressure measuring device. 13A and 13B are diagrams showing calculation results of blood flow in a blood circuit pressure measuring instrument according to an embodiment. FIG. 13 is a diagram showing the calculation results of blood flow in a blood circuit pressure measuring instrument according to another embodiment. FIG. 13 is a diagram showing the calculation results of blood flow in a blood circuit pressure measuring instrument according to another embodiment. FIG. 1 is a diagram showing the calculation results of blood flow in a prior art blood circuit pressure measuring device.

The following describes in detail the embodiments of the present disclosure with reference to the drawings. In the following, a blood circuit for extracorporeal circulation in a dialysis device will be described as a blood circuit to which the blood circuit pressure measuring device is applied, but this is an example for explanatory purposes, and the device can also be applied to blood circuits in blood purification devices other than dialysis devices.

The shapes, materials, qualities, numbers, angles, etc. described below are examples for explanatory purposes only and can be changed as appropriate depending on the specifications of the blood circuit pressure measuring device. In addition, in the following, similar elements are given the same reference numerals in all drawings, and duplicate explanations will be omitted.

Figure 1 is a schematic diagram of a blood circuit 10 for extracorporeal circulation for a dialysis device 4. The blood circuit 10 is a blood circulation circuit that connects a patient to the dialysis device 4, and circulates blood 8 outside the patient's body, by connecting blood circuit instruments and the like to a flexible tube 11 through which blood 8 flows.

The blood circuit 10 has a blood inlet 12 that introduces blood 8 from a patient's artery (not shown), a blood outlet 14 that returns blood 8 to the patient's vein, and a blood pump 16 that flows blood 8 in the blood circuit 10 from the upstream blood inlet 12 to the downstream blood outlet 14.

The dialysis device 4 includes a dialysis section 6 called a dialyzer, and a dialysis device main body 7. The dialysis section 6 is a device that performs material exchange and solute removal between blood 8 and dialysis fluid via a dialysis membrane. The dialysis section 6 has a dialysis inlet section 6a into which blood 8 is introduced from the blood circuit 10, and a dialysis outlet section 6b that outputs the blood 8 purified by the dialysis device 4 to the blood circuit 10. The dialysis device main body 7 is a device that supplies dialysis fluid to the dialysis section 6 and discharges waste liquid after material exchange and solute removal in the dialysis section 6.

The blood pump 16 is a fluid pump that draws blood 8 from the patient's artery into the blood circuit 10 via the blood inlet 12, sends the drawn blood 8 to the dialysis device 4, and returns the blood 8 purified by the dialysis device 4 to the patient's vein via the blood outlet 14.

The blood circuit 10 between the blood inlet 12 and the dialysis device 4 is provided with a vent blood pressure measurement site 18, a blood pump 16, and a PD pressure measurement site 20, in that order, and the blood circuit 10 between the dialysis device 4 and the blood outlet 14 is provided with a return blood pressure measurement site 22.

The withdrawal blood pressure measurement site 18, PD pressure measurement site 20, and return blood pressure measurement site 22 are provided in the blood circuit 10 to monitor the pressure of the blood 8 flowing through the blood circuit 10. The withdrawal blood pressure measurement site 18 is connected to the blood inlet 12 and measures the pressure of the blood 8 in the withdrawal state. The withdrawal blood pressure measurement site 18 is upstream of the blood pump 16, so the pressure of the blood 8 is negative, but if the negative pressure is too strong, hemolysis may occur. The PD pressure measurement site 20 is downstream of the blood pump 16 and just before the dialysis unit 6 (Pre-Dialyzer), so the pressure of the blood 8 is positive, but if the positive pressure is too strong, blood cells in the blood 8 may be crushed. The return blood pressure measurement site 22 is downstream of the dialysis device 4, so the pressure of the blood 8 is positive, but if the positive pressure is insufficient, hemolysis may occur.

The pressure transducers 24, 26, and 28 are pressure transducers that measure the pressure of the blood 8 at the vent pressure measurement site 18, the PD pressure measurement site 20, and the return pressure measurement site 22, respectively, via the connection part 30.

A blood circuit pressure measuring instrument 40 is provided at at least one of the three pressure measuring sites, the vent pressure measuring site 18, the PD pressure measuring site 20, and the return pressure measuring site 22, which are provided in the blood circuit 10. Hereinafter, unless otherwise specified, the blood circuit pressure measuring instrument 40 will be referred to as the pressure measuring instrument 40.

Figure 2 shows the configuration of the PD pressure measurement site 20, where a pressure measurement instrument 40 is provided as one of three pressure measurement sites arranged in the blood circuit 10. The PD pressure measurement site 20 is arranged with a connection part 30 and a pressure measurement instrument 40 having three ports. The three ports are ports for connecting to the downstream flexible tube 11, the upstream flexible tube 11, and the pressure transducer 26, respectively.

The connection part 30 includes a flexible tube 32 for pressure measurement that connects the pressure transducer 26 to one port of the pressure measuring instrument 40, and a transducer connector 34 provided at one end of the tube 32. The connection part 30 further includes a clip 36 that can close the flexible tube 32.

The pressure measuring device 40 is composed of a housing 42 and a flexible membrane 44. The housing 42 has a major axis and a minor axis, and has an approximately spheroidal external shape. The housing 42 is composed of a divided structure including a lower housing 50 and an upper housing 70 that fits into the lower housing 50. The flexible membrane 44 is a membrane that divides the chamber 46, which is the internal space of the housing 42, into an air chamber 80 in which no blood 8 flows and in which air for pressure measurement is present, and a blood chamber 82 (see Figure 7) in which blood 8 flows. The flexible membrane 44 is a flexible membrane that displaces according to the internal pressure of the blood chamber 82 as the first chamber and the internal pressure of the air chamber 80 as the second chamber.

The lower housing 50 has an inlet port 52 through which blood 8 is introduced and an outlet port 54 through which blood 8 is discharged. The inlet port 52 is a port connected to the upstream flexible tube 11 in the blood circuit 10. The outlet port 54 is a port connected to the downstream flexible tube 11. A blood flow agitation rib 90 protruding from the inner surface of the lower housing 50 is provided on the bottom side of the lower housing 50. The configuration and function of the blood flow agitation rib 90 will be described later.

The upper housing 70 has a pressure measurement port 72 that communicates with the air chamber 80 of the chamber 46 and outputs a pressure change caused by a change in the volume of the air chamber 80 in response to the displacement of the flexible membrane 44. The pressure measurement port 72 is a port that is connected to the pressure transducer 26 via the flexible tube 32 of the connection part 30. The flexible tube 32 does not have to be provided.

In the pressure measuring instrument 40, in Fig. 3 and subsequent figures, three orthogonal directions are shown: the flow axis direction, the up-down direction, and the left-right direction. The flow axis direction is parallel to the direction of flow of blood 8. Since the outer shape of the pressure measuring instrument 40 is approximately a spheroid, the mating surface where the lower housing 50 and the upper housing 70 are mated is elliptical, and the long axis direction of the ellipse of the mating surface is the flow axis direction. When distinguishing between the two directions in the flow axis direction, the direction facing the inlet port 52 side of the lower housing 50 is called one side, and the opposite side to the inlet port 52 side is called the other side. The up-down direction is the direction connecting the lower housing 50 and the upper housing 70, and when distinguishing between the two directions in the up-down direction, the direction facing the lower housing 50 side is called the down direction, and the direction facing the upper housing 70 side is called the up direction. The left-right direction is the short axis direction of the ellipse in the elliptical shape of the mating surface of the lower housing 50 and the upper housing 70. When distinguishing between the left and right directions, the right hand direction is the right side when viewed from one side of the flow axis direction, and the left hand direction is the left side.

As shown in Figures 3, 4, 6, and 7, the upper housing 70 has a dome shape that is convex on the upper side and concave on the lower side. The dome shape is a long aspheric shape along line B-B connecting the inlet port 52 and the outlet port 54, has a nearly uniform wall thickness t70, and when viewed in cross section, has a curved shape that is convex on the upper side and concave on the lower side, forming an internal space 46U that is concave on the lower side. An elliptical ring-shaped flange 74 is provided at the lower end of the dome shape.

The pressure measurement port 72 is a pipe portion that is located on the B-B line of the dome shape closer to the inlet port 52 than the midpoint between the inlet port 52 and the outlet port 54, and extends upward perpendicular to the B-B line. The lower end of the pipe portion that is the pressure measurement port 72 is an opening that penetrates the thickness t70 of the downward concave curved shape of the upper housing 70. The structure that extends perpendicularly is an example for explanatory purposes, and the extension direction of the pressure measurement port 72 may be a direction parallel to the B-B line from the outer peripheral surface of the dome shape, or may be appropriately inclined. In some cases, the pressure measurement port 72 may extend upward perpendicular to the B-B line from the outer peripheral surface of the dome shape, and then extend parallel to the B-B line.

As shown in Figures 3 to 8, the lower housing 50 has a dome shape that is convex on the lower side and concave on the upper side, and the length between the left and right side walls of the lower housing 50 as seen from the inlet port 52 increases toward the upper side. The dome shape is a long aspheric shape along the line B-B connecting the inlet port 52 and the outlet port 54, and has a nearly uniform wall thickness t50 except for the inlet port 52 side, the outlet port 54 side, and the vicinity of the blood flow agitation rib 90. When viewed in cross section, the dome shape is a curved shape that is convex downward and concave upward, forming an upper concave internal space 46D. The bottom surface of the upper concave internal space 46D is also the bottom surface of the blood chamber 82, so if it is called the blood chamber bottom surface 83, the part of the blood flow agitation rib 90 protrudes upward from the blood chamber bottom surface 83.

An elliptical annular flange 56 is provided at the dome-shaped upper end of the lower housing 50. The surface where the flange 56 of the lower housing 50 and the flange 74 of the upper housing 70 face each other is the mating surface 48. A fitting groove 58 is provided in the flange 56. The groove bottom surface 60 of the fitting groove 58 is the mounting surface where the flange (not shown) of the flexible membrane 44 is received and attached to the lower housing 50.

The inlet port 52 is a pipe portion connected to one side of the upper concave internal space 46D, and the outlet port 54 is a pipe portion connected to the other side of the upper concave internal space 46D. The other end of the pipe portion that is the inlet port 52 becomes an inlet side opening that penetrates the wall thickness t50 of the upper concave curved shape of the lower housing 50. The one end of the pipe portion that is the outlet port 54 becomes an outlet side opening that penetrates the wall thickness t50 of the upper concave curved shape of the lower housing 50.

The material for the upper housing 70 and the lower housing 50 must be hard enough that it hardly changes shape due to blood temperature, outside air temperature, external pressure, etc., and must also be biocompatible because it comes into direct and indirect contact with the blood 8. Examples of such hard materials that can be used include hard plastics such as polyvinyl chloride, polycarbonate, and polypropylene.

The flexible membrane 44 is a flexible membrane-like member with a substantially uniform thickness t44 and a convex upper and concave lower curved shape that matches the convex upper and concave lower curved shape of the upper housing 70. An elliptical annular flange is provided at the lower end of the curved shape to be fitted into the fitting groove 58 of the lower housing 50.

The flexible membrane 44 must be made of a soft material that flexibly deforms under pressure, and must also be biocompatible because it comes into direct and indirect contact with the blood 8. Examples of such soft materials that can be used include polyvinyl chloride, silicone resin, styrene-based thermoplastic elastomer, and styrene-based thermoplastic elastomer compound.

The pressure measuring device 40 including the housing 42 and the flexible membrane 44 is assembled as follows: The flange of the flexible membrane 44 is received in the fitting groove 58 of the lower housing 50, and is integrated using a suitable integration means.

As a means of integration, it is possible to use heat fusion bonding, which is a common joining method for synthetic resins, or adhesives. As heat fusion bonding, it is possible to use high-frequency welding, induction heating welding, ultrasonic welding, friction welding, spin welding, hot plate welding, hot wire welding, etc. As adhesives, it is possible to use cyanoacrylate-based, epoxy-based, polyurethane-based, synthetic rubber-based, ultraviolet curing type, modified acrylic resin-based, hot melt type, etc.

In the pressure measuring device 40 in which the flexible membrane 44 is disposed, the flexible membrane 44 divides the chamber 46, which is the internal space of the housing 42, into an air chamber 80 and a blood chamber 82. The air chamber 80 is a space in which air for pressure measurement exists, and is a space formed between the lower wall surface of the outer shell of the upper housing 70, which has a thickness t70 and a downwardly concave curved shape, and the upper surface of the flexible membrane 44. The blood chamber 82 is a space through which blood 8 introduced from the inlet port 52 and discharged from the outlet port 54 passes, and spans both the upper housing 70 and the lower housing 50.

When the initial shape of the flexible membrane 44 is a curved shape that matches the curved shape of the upper housing 70, the flexible membrane 44 uses the groove bottom surface 60 of the fitting groove 58 provided in the lower housing 50 as the attachment surface, so the flexible membrane 44 in the initial state is above the mating surface 48. Therefore, the flexible membrane 44 in the initial state divides the internal space 46U of the upper housing 70 into an air chamber 80 and a blood chamber 82U in the upper housing 70. Since the flexible membrane 44 in the initial state is not disposed in the internal space 46D of the lower housing 50, the air chamber 80 is only above the mating surface 48, and the entire internal space 46D of the lower housing 50 becomes the blood chamber 82D in the lower housing 50.

The flexible membrane 44 is a membrane that divides the chamber 46, which is the internal space of the housing 42, into a blood chamber 82 and an air chamber 80, and is flexible in response to pressure, so it displaces from its initial state according to the internal pressure of the blood chamber 82 and the internal pressure of the air chamber 80. In other words, when the blood chamber 82 becomes negative pressure, the flexible membrane 44 displaces downward until the internal pressures of the blood chamber 82 and the air chamber 80 are in equilibrium.

The above-mentioned initial shape of the flexible membrane 44 is an example for explanatory purposes, and can be changed as appropriate depending on the pressure range of the blood 8 to be measured and the specifications of the pressure measuring instrument 40. For example, when the initial shape of the flexible membrane 44 is convex upward, the range of negative pressures that can be measured is wide, making it suitable for pressure measurement in locations where negative pressures are expected. On the other hand, when the initial shape of the flexible membrane 44 is convex downward, the range of positive pressures that can be measured is wide, making it suitable for pressure measurement in locations where positive pressures are expected. The shape of the flexible membrane 44 may be flat.

With the pressure measuring device 40 configured as described above, the shape of the blood chamber 82 is approximately spheroidal, and the flow axis direction is the major axis of the ellipsoid, so that the radius of curvature of the inner wall surface of the blood chamber 82 is smallest both near the inlet port 52 and the outlet port 54. This makes it possible to reduce the diffusion width of the blood 8 when it flows into the blood chamber 82 from the inlet port 52, and also to narrow the width of the blood flow near the outlet port 54, so that blood 8 is less likely to stagnate.

The blood flow agitation rib 90 is a member provided to suppress the stagnation of blood 8 in the blood chamber 82. The blood flow agitation rib 90 is a single beam-shaped member arranged in the width direction on the bottom side of the upper concave dome-shaped outer shell of the lower housing 50. Hereinafter, unless otherwise specified, the blood flow agitation rib 90 will be referred to as rib 90.

A single rib 90 is disposed on the lower housing 50, and its extending direction intersects with the flow of blood 8 flowing in from the inlet port 52. More specifically, the rib 90 is perpendicular to the flow direction of the inlet port 52 and parallel to the left-right direction, and the shape of the cross section perpendicular to the extending direction is approximately triangular. One of the three faces of the approximately triangular cross section is the rib bottom surface 92 perpendicular to the up-down direction, and the other two are inclined surfaces 94, 96 inclined at a predetermined inclination angle to the rib bottom surface 92, and the apex 95, which is the intersection point of the two inclined surfaces 94, 96, is above the rib bottom surface 92. In FIG. 4, which is a front view of the pressure measuring instrument 40, the rib bottom surface 92, the inclined surfaces 94, 96, and the apex 95 that constitute the approximately triangular cross-sectional shape of the rib 90 are visible, and in FIG. 5, which is a bottom view, the rib bottom surface 92 of the rib 90 is visible. If the center line of the rib 90 is taken as the center line C90-C90 in the longitudinal direction of the bottom surface, the center line C90-C90 of the rib 90 is located exactly halfway between one end face of the inlet port 52 and the other end face of the outlet port 54 in the lower housing 50. In other words, the rib 90 is located equidistant from the inlet port 52 and the outlet port 54, with the center line C90-C90 perpendicular to the flow axis direction. The length of the rib 90 in the left-right direction is longer than the length in the flow axis direction.

The rib 90 has two inclined surfaces 94 and 96. The inclined surface 94 is a front inclined surface that extends from the blood chamber bottom surface 83, which is the bottom surface of the internal space 46D of the lower housing 50 and the bottom surface of the blood chamber 82, toward the upper housing 70 side and the outlet port 54 side. In the following, unless otherwise specified, the inclined surface 94 is referred to as the front inclined surface 94. The inclined surface 96 is a rear inclined surface that extends from the top 95 of the front inclined surface 94 toward the lower housing side and the outlet port 54 side. In the following, unless otherwise specified, the inclined surface 96 is referred to as the rear inclined surface 96. The material of the rib 90 is the same as that of the lower housing 50. The rib 90 may be formed separately and assembled. In addition, the rib 90 does not have a groove or a through hole formed therein, which makes it easy to change the direction of the flow of the blood 8, but a groove or a through hole may be formed in the rib 90 so that the flow path is less likely to be blocked by a membrane. Additionally, grooves may be formed in areas other than the ribs 90 to prevent the flow path from being blocked by the membrane.

In the pressure measuring device 40, blood 8 is introduced from the inlet port 52, passes through the chamber 46, which is the internal space of the housing 42, and is discharged from the outlet port 54. This has a straight component that flows toward the inlet port 52 and the outlet port 54, which is the shortest distance. In addition to the straight component, the flow of blood 8 has a wall flow component that flows along the inner wall side of the curved shape that forms the outer shell of the chamber 46. Compared to the straight component, the wall flow usually has a slower flow rate, and blood 8 is more likely to stagnate.

The ribs 90 are provided to agitate the flow of blood 8 near the area 9 indicated by the two-dot chain line, thereby preventing blood 8 from accumulating. The ribs 90 and blood 8 (white arrows) are shown in Figures 9 to 11.

The blood 8 introduced from the inlet port 52 strikes the front slope 94 of the rib 90, and the flow direction is expanded to include left-right and upward components. A portion of the blood 8 is guided left-right by the rib 90 and flows toward the periphery of the housing, then swirls along the wall of the housing, while another portion of the blood 8 swirls upward along the wall of the rib 90 and joins the blood flow flowing in from the inlet port 52. In other words, the rib 90 creates a left-right component in the blood flow, creating a flow that stirs the entire blood. The rear slope 96 of the rib 90 raises the blood 8 flowing between the rib 90 and the outlet port 54 that could not flow into the outlet port 54, and joins the blood flow toward the outlet port 54.

In the above, the center line C90-C90 of the rib 90 is located at the midpoint between the inlet port 52 and the outlet port 54 in the internal space 46D of the lower housing 50 and is perpendicular to the flow axis direction of the inlet port 52. Alternatively, the center line C90-C90 of the rib 90 may be arranged to have a predetermined angle with respect to the flow axis direction. By arranging the center line C90-C90 of the rib 90 to have a predetermined angle other than perpendicular to the flow axis direction, the extension length of the rib 90 in the internal space 46D of the lower housing 50 can be made longer than when the center line C90-C90 is arranged perpendicular to the flow axis direction. The center line C90-C90 may extend from one side of the rib 90 to the other side while extending so as to intersect with the flow axis direction of the inlet port 52. In addition, a plurality of ribs 90 may be arranged so as to be intermittently formed in the flow axis direction or the left and right direction of the inlet port 52. In addition, the rib 90 does not have to be arranged exactly in the middle between one side and the other side of the lower housing 50, and may be arranged on the inlet port 52 side, for example.

The pressure measuring device 100 shown in Figures 12 to 16 is a diagram showing an example in which, instead of the single rib 90 in the pressure measuring device 40, two ribs 112, 114 are arranged as a rib pair 110 between the inlet port 52 and the outlet port 54.

12, 13, and 14 are front, bottom, and side views of the pressure measuring instrument 100, respectively, corresponding to FIGS. 4, 5, and 6 of the pressure measuring instrument 40 using the rib 90. FIG. 15 is a cross-sectional view of the pressure measuring instrument 40 corresponding to FIG. 7, and FIG. 16 is a perspective view of the pressure measuring instrument 40 corresponding to FIG. 8. The pressure measuring instrument 100 and the pressure measuring instrument 40 have the same configuration, except for the difference in the rib 90 and the rib pair 110. For example, the upper housing 70 of the pressure measuring instrument 100 is the same as the upper housing 70 of the pressure measuring instrument 40, so a top view of the pressure measuring instrument 100 is omitted. Below, we will mainly explain the parts related to the rib pair 110, and omit detailed explanations of the chamber 138, blood chamber 120, etc., which are the same components as those of the pressure measuring instrument 40.

The two ribs 112, 114 that make up the rib pair 110, like the rib 90, have a cross-sectional shape perpendicular to the extension direction that is approximately triangular. The approximately triangular shape in the cross-section of the rib 112 has a rib bottom surface 122, a front slope 124, a rear slope 126, and an apex 125. The approximately triangular shape in the cross-section of the rib 114 has a rib bottom surface 132, a front slope 134, a rear slope 136, and an apex 135.

The center lines C112-C112 and C114-C114 of the rib bottom surfaces 122 and 132 of the two ribs 112 and 114 are disposed at the same predetermined angle +θ1 with respect to the flow axis direction. The sign of the inclination angle is positive (+) when the angle is measured from one side of the flow axis direction toward the rightward extension direction of the center lines C112-C112 and C114-C114. One example of the predetermined angle is +θ1 = approximately +110 degrees.

The two ribs 112, 114 are set to a predetermined distance S1 between them along the flow axis direction B-B on the bottom surface 83 of the blood chamber in the lower housing 118. The ribs are arranged so that, under the predetermined distance S1, the distance from the end 53 on the inlet port 52 side to the rib 112 is the same as the distance from the end 55 on the outlet port 54 side to the rib 114. The predetermined distance S1 may be set as appropriate, and in this embodiment, the two ribs 112, 114 are formed to sandwich a midpoint between one side and the other side.

Figures 17 and 18 show the blood flow agitation effect of the rib pair 110, and correspond to Figures 9 and 10 for the pressure measurement instrument 40 using one rib 90. Note that Figure 11 for the pressure measurement instrument 40 is a cross-sectional view taken along the center line C90-C90 of the rib 90, but the cross-sectional views taken along the center lines C112-C112 and C114-C114 for the two ribs 112, 114 in the rib pair 110 are almost the same as Figure 11. Therefore, in the pressure measurement instrument 100, the drawing corresponding to Figure 11 for the pressure measurement instrument 40 has been omitted. In Figures 17 and 18, the ribs 112, 114 and blood 8 (white arrows) are shown.

Blood 8 introduced from the inlet port 52 hits the front slope 124 of the rib 112 arranged on one side of the rib pair 110. The rib 112 extends at an angle, and in this embodiment, the blood flow hitting the rib 112 and rib 114 has strong rightward and upward components. The blood 8 that passes the upper side of the rib 112 is also guided to the right by the rib 114, and merges with the flow that has been changed to the rightward direction by the rib 112 and heads toward the outlet port 54. The blood 8 that cannot flow into the outlet port 54 flows to the left along the wall of the housing, and heads toward the inlet port 52 along the wall to join the blood flow flowing in from the inlet port 52, or turns along the wall to join the flow on the right again. The rear slope 126 of the rib 112 and the rear slope 136 of the rib 114 guide the blood 8 flowing between the rib 112 and the rib 114 or between the rib 114 and the outlet port 54 upward and to the right, where it merges with the strong blood flow on the right side and other flows toward the outlet port 54.

The two ribs 112, 114 in the rib pair 110 extend at an angle, which allows the range of blood flow mixing to be increased. The specified angle θ1 and the specified interval S1 of the two ribs 112, 114 in the rib pair 110 can be set appropriately from the viewpoint of ensuring a suitable mixing effect by the rib pair 110, based on the thrombus suppression specifications of the pressure measuring instrument 100, etc. Note that the angle θ of the two ribs 112, 114 may be different from each other.

In the pressure measurement instrument 140, Figs. 19 and 20 are respectively a front view and a bottom view corresponding to Figs. 12 and 13 of the pressure measurement instrument 100 using the rib pair 110. Fig. 14 is a side view of the pressure measurement instrument 100, but the side view of the pressure measurement instrument 140 using the rib pair 150 is almost the same as Fig. 14, so the side view of the pressure measurement instrument 140 is omitted. Also, Fig. 15 of the pressure measurement instrument 100 is a cross-sectional view taken along line B-B, which is the flow axis direction, but the cross-sectional view of the pressure measurement instrument 140 using the rib pair 150 along line B-B is almost the same as Fig. 15. Therefore, the cross-sectional view of the pressure measurement instrument 140 along line B-B is omitted. Fig. 21 is a perspective view corresponding to Fig. 16 of the pressure measurement instrument 100.

The pressure measuring instrument 140 and the pressure measuring instrument 100 have the same configuration, with the only difference being the rib pairs 150 and 110. For example, the upper housing 70 constituting the housing 156 of the pressure measuring instrument 140 is the same as the upper housing 70 of the pressure measuring instrument 100, so a top view of the pressure measuring instrument 140 is omitted. Below, we will mainly explain the parts related to the rib pairs 150 in the lower housing 158, and will omit a detailed explanation of the components that are the same as those of the pressure measuring instrument 100.

The two ribs 152, 154 that make up rib pair 150, like rib pair 110, have a cross-sectional shape perpendicular to the extension direction that is approximately triangular. The approximately triangular cross-section of rib 152 has a rib bottom surface 162, a front slope 164, a rear slope 166, and an apex 165. The approximately triangular cross-section of rib 154 has a rib bottom surface 172, a front slope 174, a rear slope 176, and an apex 175.

The center lines C152-C152 and C154-C154 of the rib bottom surfaces 162 and 172 of the two ribs 152 and 154 are disposed at different predetermined angles +θ2 and -θ2 with respect to the flow axis direction. The sign of the angle is positive (+) when measured from one side of the flow axis direction toward the rightward extension direction of the center lines C152-C152 and C154-C154, and negative (-) when measured toward the leftward extension direction of the center lines C152-C152 and C154-C154. The predetermined angle of the rib 152 is set to -θ2, and the predetermined angle of the rib 154 is set to +θ2.

In this embodiment, the two ribs 152, 154 are set to a predetermined distance S2 between them along the flow axis direction B-B on the bottom surface 83 of the blood chamber in the lower housing 158. And, under the predetermined distance S2, they are arranged so that the distance from the end 53 on the inlet port 52 side to the rib 152 is the same as the distance from the end 55 on the outlet port 54 side to the rib 154.

The predetermined angle ±θ2 and the predetermined interval S2 are set from the viewpoint of ensuring an appropriate stirring effect by the rib pair 150 based on the thrombus suppression specifications of the pressure measuring instrument 140. The absolute values of the predetermined angles +θ2, -θ2 may be set to the same as the absolute value of the predetermined angle +θ1 in the pressure measuring instrument 100. In that case, the predetermined angle (-θ2) of the rib 152 = (approximately -110 degrees), and the predetermined angle (+θ2) of the rib 154 = (approximately +110 degrees). The predetermined interval S2 may be set to the same as the predetermined interval S1 of the pressure measuring instrument 100. The angles θ of the two ribs 152, 154 may be different, and the intervals between them may also be changed as appropriate.

Figure 22 shows rib pairs 150 and blood 8 (white arrows), and corresponds to Figure 17 for the pressure measurement device 100.

Blood 8 introduced from the inlet port 52 hits the front slope 164 of the rib 152 arranged on one side of the rib pair 150. The rib 152 extends at an angle, and in this embodiment, the blood flow that hits the rib 152 has a strong leftward component and an upward component. The rib 154 extends in a direction intersecting with the rib 152, and the blood flow that hits the rib 154 has a strong rightward component and an upward component. The blood 8 guided to the left by the rib 152 flows toward the outlet port 54 along the left housing wall surface, or flows toward the gap between the rib 152 and the rib 154. Of the blood 8 that is directed toward the outlet port 54, the blood 8 that cannot flow into the outlet port 54 is guided upward or to the right along the rear slope 176 of the rib 154 and merges with the strong blood flow toward the outlet port 54. Part of the blood 8 flowing between the ribs 152 and 154 flows toward the front slope 174 of the rib 154, and part of it flows toward the rear slope 166 of the rib 152, and is guided by these slopes to flow upward and to the right, where it joins with the strong blood flow toward the outlet port 54. Part of the blood 8 that passes above the rib 152 collides with the front slope 174 of the rib 154, adding a rightward component. The blood 8 guided to the front slope 174 of the rib 154 flows toward the outlet port 54 along the right housing wall surface. The blood 8 that cannot flow into the outlet port 54 is guided upward or to the left along the rear slope 176 of the rib 154, where it joins with the strong blood flow toward the outlet port 54.

The specified angles -θ2 and +θ2 of the two ribs 152, 154 in the rib pair 150 and the specified spacing S2 are set from the perspective of ensuring an appropriate stirring effect by the rib pair 150, based on the thrombus suppression specifications of the pressure measuring device 140, etc.

The effects of the pressure measuring instruments 40, 100, and 140 configured as described above will be explained in comparison with pressure measuring instruments of the prior art. Figures 23 to 25 show the configuration of a pressure measuring instrument 200 of the prior art that does not have a rib 90 or rib pairs 110 and 150.

Figure 23 is a front view of the pressure measuring instrument 200, and corresponds to Figures 4, 12, and 19 for the pressure measuring instruments 40, 100, and 140. Figure 24 is a bottom view of the pressure measuring instrument 200, and corresponds to Figures 5, 13, and 20 for the pressure measuring instruments 40, 100, and 140. Figure 25 is a perspective view of the lower housing 210 of the pressure measuring instrument 200 with the upper housing 70 and flexible membrane 44 (not shown) removed, and corresponds to Figures 8, 16, and 21 for the pressure measuring instruments 40, 100, and 140.

The pressure measuring device 200 of the prior art differs from the pressure measuring devices 40, 100, 140 in that it does not have a rib 90 or rib pairs 110, 150, so the housing 202 differs from the housings 42, 116, 156 of the pressure measuring devices 40, 100, 140. The flexible membrane 44 is the same as the flexible membrane 44 of the pressure measuring devices 40, 100, 140.

As shown in FIG. 25, the bottom surface 83 of the blood chamber in the upper concave internal space 206D of the lower housing 210 does not have the rib 90 or the rib pair 110, 150 protruding, but instead has a groove 220 connecting the inlet port 52 and the outlet port 54.

The groove 220 is provided to prevent blood 8 from being introduced from the inlet port 52 and blood 8 from being discharged from the outlet port 54 when the internal pressure of the blood chamber of the pressure measuring instrument 200 becomes low and the flexible membrane 44 bends excessively downward in the blood chamber and adheres to the blood chamber bottom surface 83. Even if the flexible membrane 44 bends excessively downward in the blood chamber and adheres to the blood chamber bottom surface 83, it does not drop to the bottom surface of the groove 220, so blood 8 is discharged from the inlet port 52 through the groove 220 to the outlet port 54. In the pressure measuring instruments 40, 100, and 140, the rib 90 and the rib pair 110 and 150 protrude upward from the blood chamber bottom surface 83. Therefore, even if the internal pressure of the blood chamber becomes low, the flexible membrane 44 is supported on the lower side by the rib 90 and the rib pair 110 and 150 and does not adhere to the blood chamber bottom surface 83. In other words, the pressure measuring device 40, 100, 140 does not need to have a groove 220.

Next, we will explain the results of a comparison made by simulation calculation of the flow of blood 8 in the blood chamber for the pressure measuring instruments 40, 100, and 140 and the prior art pressure measuring instrument 200. Figures 26 to 30 show the calculation direction of the age of air and the comparison results. Figures 31 to 34 show the comparison results of blood flow (stream line) and blood flow velocity.

The age of air is the time it takes for blood 8 that has flowed into the blood chamber 82 to reach the destination. In other words, the shorter the age of air, the sooner the blood flow will arrive at the destination. The simulation calculation of the age of air was performed for each position on the two mutually orthogonal dividing planes P and Q of the blood chamber 82, which were divided into four. In FIG. 26, the pressure measuring instrument 40 is used as an example, and the two mutually orthogonal dividing planes P and Q of the blood chamber 82 are shown with oblique lines. The dividing plane P in FIG. 26 is the mating plane 48 between the upper housing 70 and the lower housing 50 (see FIG. 7). The dividing plane Q is a plane that is orthogonal to the mating plane 48 and includes the line B-B connecting the inlet port 52 and the outlet port 54. The simulation calculation of the age of air was performed by calculating the time it takes for blood 8 at each position in the dividing plane P and each position in the dividing plane Q to be discharged to the outlet port 54, and displaying the results as the air age distribution on the dividing planes P and Q. The distribution of air age is shown by the density of the stitch pattern, and as the air age goes from short to long, the stitch pattern density goes from zero to sparse, then gradually becomes dense and changes to a blackened state.

Figure 27 shows the results of calculating the distribution of the age of air in the pressure measuring instrument 40, Figure 28 shows the results of calculating the distribution of the age of air in the pressure measuring instrument 100, and Figure 29 shows the results of calculating the distribution of the age of air in the pressure measuring instrument 140. Figure 30 shows the results of calculating the distribution of the age of air in the pressure measuring instrument 200 of the prior art.

Comparing these figures, it can be seen that in the pressure measuring device 200 of the prior art, the age of air is longer in areas far from the inlet port 52 and the outlet port 54, and in areas where the radius of curvature of the inner wall surface is large. Area 9 in Figures 9 to 11 indicates this area where the age of air is longer. It can be seen that in the pressure measuring device 40 with the rib 90, and the pressure measuring devices 100 and 140 with the rib pairs 110 and 150, the age of air is generally shorter than in the pressure measuring device 200 of the prior art, which indicates that the entire area is more easily stirred and blood flow stagnation is suppressed.

Next, we will describe the simulation calculation of blood flow (stream line) and blood flow velocity. For blood flow (stream line), the flow of blood 8 introduced into the inlet port 52 was divided into bundles of thin blood 8 flows, and the flow path and blood flow velocity were calculated for each thin blood 8 flow. The calculation results show the flow path as a three-dimensional display of streamlines, and the blood flow velocity is shown by adding shading to the streamlines.

Figure 31 shows the calculation results of blood flow and blood flow velocity in pressure measuring device 40, Figure 32 shows the calculation results of blood flow and blood flow velocity in pressure measuring device 100, and Figure 33 shows the calculation results of blood flow and blood flow velocity in pressure measuring device 140. Figure 34 shows the calculation results of blood flow and blood flow velocity in pressure measuring device 200 of the prior art.

Comparing these figures, in Figure 34, although there is a flow that swirls in the vertical direction, there is little flow that swirls in the horizontal direction, and no flow that follows along the side wall surface is formed. On the other hand, in Figure 31, not only is there a flow that swirls in the vertical direction, but also a flow that swirls in the horizontal direction, making it easier for the flow to reach the periphery of the housing. Also, in Figure 32, a straight flow is generated on the right side, and a horizontal swirling flow is generated on the left side and in the center. Also, in Figure 33, a vertical swirling flow is generated on the right side, and a horizontal swirling flow is generated on the left side. That is, in Figures 31 to 33, there is a flow that swirls in the horizontal direction, and a flow that follows along the side wall surface is formed.

Taking these factors into consideration, it can be seen that pressure measuring instruments 40, 100, and 140 are less likely to cause retention near the periphery of the housing compared to the pressure measuring instrument 200 of the prior art.

Although a representative embodiment has been described above, this is merely an example for the purpose of explanation, and the present disclosure is not limited to the above embodiment. In the present disclosure, a lateral swirling flow is generated by adding a lateral flow component to the blood flow through the rib, and the configuration may be changed as appropriate. For example, in the above embodiment, the housing has an inner shape of a substantially spheroid, but it may have an appropriate shape as determined by the specifications of the blood circuit pressure measuring instrument. Even if the cross section is rectangular, the fluidity near the peripheral portion can be improved by providing the rib in the present disclosure. It is preferable that the inner shape is approximately curved. In the embodiment, the inlet port 52 is arranged so that the axial direction faces the center of the housing, but the inlet port 52 may extend in a tangential direction to the housing, and may be positioned in any way. In this case, the rib may be provided at a position where it collides with the blood flowing out from the inlet port 52. In the embodiment, the outlet port 54 faces the inlet port 52 and is positioned in series, but it may be positioned anywhere, for example, it may be positioned in parallel with the inlet port 52. The blood flow changes depending on the positions of the inlet port 52 and the outlet port 54, but the important point is to change the blood flow via the ribs on the lower surface of the housing and form a blood flow in a region where blood flow is difficult to form without the ribs. In particular, since the peripheral region of the housing is prone to stagnation, it is preferable to converge the diffusion direction of the blood flow in a predetermined direction using the ribs to form a blood flow in the peripheral region, and it is also preferable to direct the diffused blood flow to a strong flow toward the outlet port 54. In order to form such a blood flow, the top of the rib is preferably located above the lower end of the inlet port 52 and below the upper end, and it is also preferable that it extends in a direction intersecting the blood flow flowing through the inlet port 52. Furthermore, in the embodiment, the cross-sectional shape of the rib is approximately triangular, but it may be rectangular, semicircular, semi-elliptical, or other cross-sectional shapes. In addition, the position where the rib is provided does not have to be the bottommost surface of the lower housing. For example, if the inlet port 52 is tangential to the housing, it may be provided on the side wall of the lower housing. In addition, although an air chamber is provided in the embodiment, the fluid does not have to be air and may be liquid.

4 Dialysis device, 6 Dialysis section, 6a Dialysis inlet section, 6b Dialysis outlet section, 7 Dialysis device main body, 8 Blood, 9 Area, 10 Blood circuit, 11, 32 Tube, 12 Blood inlet, 14 Blood outlet, 16 Blood pump, 18 Return blood pressure measurement site, 20 PD pressure measurement site, 22 Return blood pressure measurement site, 24, 26, 28 Pressure transducer, 30 Connection part, 34 Transducer connector, 36 Clip, 40, 100, 140, 200 (for blood circuit) Pressure measurement device, 42, 116, 156, 202 Housing, 44 Flexible membrane, 56 Flange, 46, 138 Chamber, 46D, 206D (in lower housing) Internal space, 46U (in upper housing) Internal space, 48 Mating surface, 50, 118, 158, 210 Lower housing, 52 Inlet port, 53, 55 End, 54 Outlet port, 58, 220 Groove, 60 Groove bottom, 70 Upper housing, 72 Pressure measurement port, 80 Air chamber, 82, 120 Blood chamber, 82D Blood chamber (in lower housing), 82U Blood chamber (in upper housing), 83 Blood chamber bottom, 90, 112, 114, 152, 154 (for mixing blood flow) Ribs, 92, 122, 132, 162, 172 Rib bottom, 94, 124, 134, 164, 174 (Front) Slope, 95, 125, 135, 165, 175 Top, 96, 126, 136, 166, 176 (Rear) Slope, 110, 150 Rib pair.

Claims (7)

A blood circuit pressure measuring device disposed in a blood circuit to measure the pressure of blood flowing through the blood circuit, comprising:
a housing including a lower housing provided with an inlet port through which the blood is introduced and an outlet port through which the blood is discharged, and an upper housing having a pressure measurement port;
a flexible membrane that divides a chamber, which is an internal space of the housing, into a first chamber through which the blood introduced from the inlet port and discharged from the outlet port passes, and a second chamber in which a fluid for pressure measurement is present, the flexible membrane being displaced in response to the internal pressures of the first chamber and the second chamber;
A blood flow agitation rib ;
A blood circuit pressure measuring instrument, wherein the length of the blood flow agitating rib in a direction perpendicular to the direction connecting the inlet port and the outlet port and the direction connecting the lower housing and the upper housing is longer than the length of the blood flow agitating rib in the direction connecting the inlet port and the outlet port . The blood circuit pressure measuring device according to claim 1, wherein the blood flow agitation rib has a front side slope that extends obliquely from the bottom surface of the lower housing toward the upper housing side and the outlet port side. The blood circuit pressure measuring device according to claim 2, wherein the blood flow agitation rib has a rear slope that extends from the top toward the lower housing side and the outlet port side. The blood circuit pressure measuring device according to claim 1, wherein the length between the left and right side walls of the lower housing as viewed from the inlet port increases toward the upward direction. The blood circuit pressure measuring device according to claim 1, wherein the top of the blood flow agitation rib is located below the upper end of the inlet port. 2. The blood circuit pressure measuring instrument according to claim 1, wherein the blood flow agitating rib extends in a direction inclined with respect to a direction connecting the inlet port and the outlet port . A blood circuit pressure measuring device disposed in a blood circuit to measure the pressure of blood flowing through the blood circuit, comprising:
a housing including a lower housing provided with an inlet port through which the blood is introduced and an outlet port through which the blood is discharged, and an upper housing having a pressure measurement port;
a flexible membrane that divides a chamber, which is an internal space of the housing, into a first chamber through which the blood introduced from the inlet port and discharged from the outlet port passes, and a second chamber in which a fluid for pressure measurement is present, the flexible membrane being displaced in response to the internal pressures of the first chamber and the second chamber;
a blood flow agitation rib extending from a bottom surface of the lower housing toward the upper housing;
Equipped with
A blood circuit pressure measuring instrument, wherein a plurality of the blood flow agitating ribs are arranged in a direction connecting the inlet port and the outlet port .

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