Catheter

Abstract

To provide a catheter which can increase echo luminance of a reflection wave of an echo beam.SOLUTION: In a catheter 10, a main lumen 20 extends in an axial direction of a catheter body 16 inside the catheter body 16, and a distal end and a proximal end communicate with the outside of the catheter body 16 to allow the circulation of a fluid. A sub-lumen 22 extends in an axial direction or in a direction intersecting the axial direction at least in a distal end part 30 inside the catheter body 16, and at least a distal end 28 is blocked. The sub-lumen is filled with a gas and does not allow a liquid to be flown in.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to catheters. [Background technology]

[0002] Patent Documents 1 and 2 disclose catheters. The catheter has a tubular catheter body. The catheter body has an inner lumen extending axially inside the catheter body. The distal and proximal ends of the inner lumen are connected to the outside of the catheter body. A plurality of bubbles are formed on the circumferential wall of the catheter body that forms the inner lumen. When an ultrasound wave (echo beam) is irradiated onto the catheter from outside the living body while the catheter is inserted into a living body, the echo beam is reflected at the boundaries between the circumferential wall of the catheter body and each of the plurality of bubbles due to the difference in acoustic impedance between the circumferential wall and the bubbles. The probe of the ultrasound device receives the reflected wave of the echo beam, making it possible to identify the position of the catheter (position of the bubbles) within the living body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-190275 [Patent Document 2] Japanese Patent Publication No. 2020-203076 Summary of the Invention [Problem to be solved by the invention]

[0004] If the reflection intensity of the echo beam at the boundary between the circumferential wall of the catheter body and the sublumen is low, the echo brightness of the reflected wave of the echo beam will be low, which makes it difficult to identify the position of the catheter in the living body based on the received reflected wave even if the probe of the ultrasound device receives the reflected wave.

[0005] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0006] (1) An aspect of the present invention is a catheter comprising a tubular catheter body, the catheter body having a main lumen, which is an inner cavity extending in the axial direction of the catheter body, with its distal and proximal ends communicating with the outside of the catheter body and allowing the flow of liquid, and a sub-lumen, which is another inner cavity extending in the axial direction or in a direction intersecting the axial direction at least at the distal end of the catheter body, with at least the distal end closed, filled with gas, and not allowing the inflow of liquid.

[0007] According to this configuration, the sub-lumen is filled with gas, thereby increasing the difference in acoustic impedance between the circumferential wall of the catheter body and the sub-lumen. As a result, when an echo beam is irradiated onto the catheter from outside the catheter, the reflection intensity of the echo beam at the boundary between the circumferential wall of the catheter body and the sub-lumen increases, thereby increasing the echo brightness of the reflected wave of the echo beam. As a result, when the probe of an ultrasound device receives the reflected wave of the echo beam while the catheter is inserted into a living body, the position of the catheter tip can be easily confirmed. Furthermore, because the catheter has a simple structure with a main lumen and a sub-lumen provided in the catheter body, the catheter can be easily manufactured using existing materials and equipment, and biocompatibility of the catheter can be ensured.

[0008] (2) In the catheter described in (1) above, the catheter body may further have an uneven portion provided on a sub-inner circumferential surface that forms the sub-lumen.

[0009] According to this configuration, the echo beam emitted from the outside of the catheter is scattered by the uneven portion, so that the echo brightness can be effectively increased.

[0010] (3) In the catheter described in (2) above, the uneven portion may be provided on the sub-inner circumferential surface at intervals in the circumferential direction of the sub-lumen.

[0011] This configuration makes it possible to effectively scatter the echo beam emitted from the outside of the catheter.

[0012] (4) In the catheter according to (2) or (3) above, the uneven portion may be provided in a plurality at intervals in the axial direction on the sub-inner circumferential surface.

[0013] This configuration effectively scatters the echo beam emitted from outside the catheter, and effectively increases the echo brightness, making it possible to easily confirm the location of the catheter when it is inserted into a living body.

[0014] (5) In the catheter according to any one of (2) to (4) above, the uneven portion may be provided in a spiral shape in the axial direction on the sub-inner circumferential surface.

[0015] This configuration allows for effective scattering of an echo beam irradiated from outside the catheter. That is, since the uneven portion is formed spirally in the axial direction, when an echo beam is irradiated onto the catheter from outside the catheter, the echo beam is scattered not only in the circumferential direction but also in the axial direction. This effectively increases the echo brightness. As a result, when the catheter is inserted into a living body, it becomes possible to easily confirm which part of the living body the catheter is inserted into.

[0016] (6) In the catheter according to any one of (1) to (5) above, the sub-lumen may extend spirally in the axial direction inside the catheter body.

[0017] With this configuration, an echo beam emitted from outside the catheter can be effectively scattered by the spiral sublumen. That is, when an echo beam is emitted onto the catheter from outside the catheter, the echo beam is scattered not only in the circumferential direction but also in the axial direction. This further increases the echo brightness. As a result, when the catheter is inserted into a living body, it becomes possible to easily confirm where the catheter is inserted into the living body.

[0018] (7) In the catheter described in (6) above, the sub-lumen may extend spirally in the axial direction so as to surround the main lumen.

[0019] With this configuration, for example, a sub-lumen can be formed to surround the main lumen using three-dimensional modeling technology. Furthermore, when an echo beam is irradiated onto the catheter from outside, the echo beam can be effectively scattered in the circumferential and axial directions. This allows the echo beam to be effectively scattered even when the angle of incidence of the echo beam with respect to the catheter changes as the catheter advances while inserted into a living body.

[0020] (8) In the catheter according to any one of (1) to (7) above, both the distal end and the proximal end of the sub-lumen may be blocked.

[0021] According to this configuration, when the cross-sectional area of the sub-lumen is relatively large, by closing both the distal and proximal ends of the sub-lumen, it is possible to effectively prevent liquid from entering.

[0022] (9) In the catheter according to any one of (1) to (8) above, the catheter body may have a plurality of the sub-lumens.

[0023] This configuration increases the difference in acoustic impedance between the peripheral wall of the catheter body and each of the sublumens, thereby effectively increasing the echogenicity when an echo beam is irradiated onto the catheter from outside the catheter.

[0024] (10) In the catheter according to (9) above, the plurality of sub-lumens may be arranged in a direction perpendicular to the axial direction inside the catheter body.

[0025] This configuration allows for even greater echogenicity.

[0026] (11) In the catheter according to (9) or (10) above, the plurality of sub-lumens may be arranged at intervals in the circumferential direction of the main lumen inside the catheter body.

[0027] With this configuration, when the probe of the ultrasound device receives a reflected wave of an echo beam while the catheter is inserted into a living body, it is possible to easily determine that the received reflected wave is a reflected wave of the echo beam reflected at the boundary between the peripheral wall of the catheter body and each of the multiple sub-lumens. [Effects of the Invention]

[0028] According to the present invention, by filling the sub-lumen with gas, the difference in acoustic impedance between the circumferential wall of the catheter body and the sub-lumen is increased. As a result, when an echo beam is irradiated onto the catheter from outside the catheter, the reflection intensity of the echo beam at the boundary between the circumferential wall of the catheter body and the sub-lumen is increased, thereby increasing the echo brightness of the reflected wave of the echo beam. As a result, when the probe of an ultrasound device receives the reflected wave of the echo beam while the catheter is inserted into a living body, the position of the catheter tip can be easily confirmed. Furthermore, because the catheter has a simple structure with a main lumen and a sub-lumen provided in the catheter body, the catheter can be easily manufactured using existing materials and equipment, and biocompatibility of the catheter can be ensured. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a cross-sectional view of a catheter according to this embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3A is a cross-sectional view of a catheter according to a first modified example, and FIG. 3B is a cross-sectional view of a catheter according to a second modified example. [Figure 4] FIG. 4A is a cross-sectional view of a catheter according to a third modified example, and FIG. 4B is a cross-sectional view of a catheter according to a fourth modified example. [Figure 5] FIG. 5A is a cross-sectional view of a catheter according to a fifth modified example, and FIG. 5B is a cross-sectional view of a catheter according to a sixth modified example. [Figure 6] FIG. 6 is a cross-sectional view of a catheter according to a seventh modification. [Figure 7] FIG. 7 is a cross-sectional view of a catheter according to an eighth modification. [Figure 8] FIG. 8 is a cross-sectional view of a catheter according to a ninth modification. DETAILED DESCRIPTION OF THE INVENTION

[0030] A catheter 10 according to this embodiment will be described with reference to FIGS. 1 and 2. The catheter 10 is connected to an inner needle member (not shown) to form a catheter assembly. At least the tip of the catheter 10 is inserted into the living body of a patient or the like, so that a portion of the catheter 10 is left indwelling within the living body. The catheter 10 is used, for example, as a central venous catheter (CVC), a peripherally inserted central catheter (PICC), a midline catheter (MC), or a peripheral venous catheter (PVC). In other words, the catheter 10 is used as an indwelling needle catheter.

[0031] The catheter 10 and the inner needle member are connected in order along the central axis (axis 14) of the catheter 10. The catheter 10 comprises a catheter body 16 and a catheter hub 18.

[0032] In the following description, the direction along the axis 14 will be referred to as the axial direction. Furthermore, the direction from the catheter hub 18 toward the catheter body 16 along the axis 14 will be referred to as the distal direction. Furthermore, the direction from the catheter body 16 toward the catheter hub 18 along the axis 14 will be referred to as the proximal direction. Furthermore, the direction perpendicular to the axis 14 will be referred to as the radial direction.

[0033] The catheter body 16 is a tubular member extending in the axial direction. The catheter body 16 is flexible. The catheter body 16 is made of, for example, a resin material. The tip of the catheter body 16 is tapered toward the tip. The tip of the catheter body 16 is the end that is inserted into a living body.

[0034] The catheter body 16 has one main lumen 20 and one sub-lumen 22. The main lumen 20 and the sub-lumen 22 are formed inside the catheter body 16 so as to be spaced apart from each other.

[0035] The main lumen 20 is an inner cavity extending in the axial direction inside the catheter body 16. The central axis of the main lumen 20 is offset radially outward from the axis 14. That is, the main lumen 20 is formed inside the catheter body 16 with the central axis of the main lumen 20 offset radially outward from the axis 14. The central axis of the main lumen 20 may coincide with the axis 14. The distal end of the main lumen 20 communicates with the exterior of the catheter body 16 at the distal end of the catheter body 16. The proximal end of the main lumen 20 communicates with the interior of the catheter hub 18 at the proximal end of the catheter body 16. The main lumen 20 allows the flow of liquids such as the patient's blood and medicinal solutions.

[0036] The sub-lumen 22 is another lumen provided inside the catheter body 16 at a location different from the main lumen 20. In the following description, the inner circumferential surface of the peripheral wall 24 of the catheter body 16 that forms the sub-lumen 22 will be referred to as the sub-inner circumferential surface 26.

[0037] The sub-lumen 22 extends axially inside the catheter body 16. The central axis of the sub-lumen 22 is offset radially outward from the axis 14. However, if the main lumen 20 is spaced radially outward from the axis 14, the central axis of the sub-lumen 22 may coincide with the axis 14.

[0038] As shown in Fig. 2, the cross-sectional shape of the sub-lumen 22 when viewed in the axial direction is circular. However, the cross-sectional shape of the sub-lumen 22 when viewed in the axial direction is not limited to a circular shape. The cross-sectional shape of the sub-lumen 22 when viewed in the axial direction may be rectangular, as indicated by the two-dot chain line. Alternatively, the cross-sectional shape of the sub-lumen 22 when viewed in the axial direction may be polygonal, such as triangular, or elliptical.

[0039] 1, the tip 28 of the sub-lumen 22 is located inside the tip section 30 of the catheter main body 16. The tip 28 of the sub-lumen 22 is closed inside the tip section 30 of the catheter main body 16. The tip 28 of the sub-lumen 22 is located within a range of, for example, 3 cm, 2 cm, or 1 cm from the tip of the catheter main body 16 toward the proximal end.

[0040] The proximal end 32 of the sub-lumen 22 is closed inside the proximal end 34 of the catheter main body 16. As shown by the two-dot chain line in Figure 1, the proximal end 32 of the sub-lumen 22 may axially pass through the proximal end 34 of the catheter main body 16 and communicate with the inside of the catheter hub 18.

[0041] The sub-lumen 22 only needs to extend axially at least at the distal end 30 inside the catheter body 16. The sub-lumen 22 does not allow the inflow of liquids such as blood and medicinal solutions.

[0042] When the cross-sectional area (inner diameter) of the sub-lumen 22 is relatively small, the proximal end 32 of the sub-lumen 22 may communicate with the interior of the catheter hub 18. When the cross-sectional area of the sub-lumen 22 is small, the effect of surface tension is relatively large, and liquids such as medicinal solutions cannot enter the sub-lumen 22.

[0043] When the cross-sectional area of the sub-lumen 22 is relatively large, it is desirable that the proximal end 32 of the sub-lumen 22 be closed inside the proximal end 34 of the catheter body 16. By closing the proximal end 32 of the sub-lumen 22, it is possible to prevent liquids such as medicinal solutions from entering the sub-lumen 22.

[0044] The sub-lumen 22 is filled with gas, that is, the sub-lumen 22 is a gas layer provided inside the catheter body 16.

[0045] The gas filling the sub-lumen 22 is a gas that may leak into the blood vessels of the living body when the catheter 10 is inserted into the living body. The gas is preferably, for example, nitrogen, oxygen, carbon dioxide, or air. If the gas is carbon dioxide, even if carbon dioxide leaks from the sub-lumen 22 into the blood vessels, the carbon dioxide dissolves in the blood, thereby preventing air embolism within the blood vessels. Alternatively, the gas may be a rare gas such as helium gas.

[0046] Furthermore, it is desirable that the sublumen 22 extend long in the axial direction from the viewpoint of the detection resolution of the ultrasonic waves (echo beam 36) in the ultrasonic device described below. Specifically, it is desirable that the lower limit of the total length of the sublumen 22 in the axial direction be equal to or greater than the minimum resolution in the lateral direction of general ultrasonic waves. For example, for 3 MHz ultrasonic waves, it is desirable that the lower limit of the total length of the sublumen 22 in the axial direction be approximately 2.5 mm to 4.0 mm.

[0047] The total axial length of the sublumen 22 is preferably, for example, 10 mm or more, 30 mm or more, or 50 mm or more. Alternatively, the total axial length of the sublumen 22 is preferably, for example, 1 / 5 or more, 1 / 3 or more, 1 / 2 or more, or 2 / 3 or more of the total axial length of the catheter body 16.

[0048] However, it is desirable that the upper limit of the total length of the sublumen 22 in the axial direction is a length such that the volume of the sublumen 22 is, for example, 10 mL or less. The upper limit of the total length of the sublumen 22 in the axial direction depends on the inner diameter of the sublumen 22.

[0049] 2, in consideration of the flow path resistance of the liquid flowing through the main lumen 20, it is desirable that the inner diameter of the sub-lumen 22 be smaller than the inner diameter of the main lumen 20. In other words, it is desirable that the inner diameter of the main lumen 20 be larger than the inner diameter of the sub-lumen 22. However, if the viscosity of the liquid flowing through the main lumen 20 is relatively low and the flow path resistance of the liquid in the main lumen 20 is low, the inner diameter of the sub-lumen 22 may be equal to or larger than the inner diameter of the main lumen 20.

[0050] As shown in Figure 1, the catheter hub 18 is a tubular member extending in the axial direction. The catheter hub 18 has a hub lumen 38 formed in the axial direction. The catheter hub 18 is desirably made of a material harder than the catheter body 16. The catheter hub 18 is made of, for example, a resin material.

[0051] The catheter hub 18 has a hub body 40 and a hub tip portion 42. The hub body 40 is the main body portion of the catheter hub 18. The hub body 40 is a tubular member. The hub body 40 is formed in a tapered shape that narrows toward the tip.

[0052] The hub tip section 42 is provided at the tip of the hub body 40. The hub lumen 38 extends axially from the hub tip section 42 to the hub body 40. The proximal end side of the catheter body 16 is inserted into the hub tip section 42. Therefore, the tip of the hub lumen 38 communicates with the main lumen 20 of the catheter body 16. Note that when the proximal end 32 of the sub-lumen 22 communicates with the outside of the catheter body 16, the sub-lumen 22 may communicate with the tip of the hub lumen 38 or the outside of the catheter 10.

[0053] The inner needle member has an inner needle and an inner needle hub. The inner needle is inserted through the main lumen 20 and the hub lumen 38. The overall length of the inner needle is sufficiently longer than the catheter body 16 and the catheter hub 18. Therefore, the tip of the inner needle protrudes distally from the tip of the catheter body 16. The base end of the inner needle protrudes proximally from the base end of the catheter body 16. The inner needle is made of a metal material such as stainless steel. The inner needle hub is connected to the base end of the inner needle. The inner needle is a tubular member having sufficient rigidity to puncture the skin of a living body. The inner needle hub may be made of the same material as the catheter hub 18. The inner needle hub is made of a resin material, for example.

[0054] The catheter assembly including the catheter 10 according to this embodiment is used as follows.

[0055] First, the user inserts the tip of the inner needle of the catheter assembly into the skin of the living body. As a result, the tip of the inner needle punctures the blood vessel of the living body and the tip of the catheter main body 16 is inserted into the blood vessel. Then, while removing the inner needle member from the catheter 10, the user advances the catheter 10 in the distal direction and inserts the tip of the catheter 10 to the target position within the blood vessel.

[0056] When the tip of the catheter main body 16 is inserted into a blood vessel, the user touches the probe of the ultrasound device to the skin of the living body. The probe irradiates an echo beam 36 into the interior of the living body. When the irradiated echo beam 36 reaches the catheter main body 16, the echo beam 36 is reflected at the boundary (sub-inner surface 26) between the peripheral wall 24 of the catheter main body 16 and the sub-lumen 22 due to the difference in acoustic impedance between the peripheral wall 24 and the sub-lumen 22. When the probe receives a reflected wave 44 of the echo beam 36, the ultrasound device displays an ultrasound image of the living body into which the tip of the catheter 10 has been inserted on a display (not shown). By viewing the ultrasound image displayed on the display, the user can identify the position of the tip of the catheter main body 16 (the tip position of the catheter 10) within the living body. Therefore, the user can insert the tip of the catheter 10 to a target position within the blood vessel while viewing the ultrasound image.

[0057] As described above, the sub-lumen 22 is filled with gas. This increases the difference in acoustic impedance between the circumferential wall 24 of the catheter body 16 and the sub-lumen 22, increasing the reflection intensity of the echo beam 36 at the boundary (sub-inner circumferential surface 26) between the circumferential wall 24 and the sub-lumen 22. That is, the echo brightness of the reflected wave 44 of the echo beam 36 at the boundary between the circumferential wall 24 and the sub-lumen 22 increases. As a result, the image of the sub-lumen 22 in the ultrasound image becomes clear, allowing the user to easily confirm the position of the tip 28 of the sub-lumen 22. Therefore, by viewing the ultrasound image, the user can easily confirm the tip position of the catheter 10 within the blood vessel of a living body. In other words, the user can easily identify the location within the living body into which the tip of the catheter 10 is inserted. This allows the user to easily insert the tip of the catheter 10 to the target position within the blood vessel.

[0058] Thereafter, a syringe, a drug solution tube, etc. are connected to the catheter hub 18 placed on the skin of the living body, and the drug solution is administered into the living body through the catheter body 16.

[0059] This embodiment has the following advantages.

[0060] 1 and 2, filling the sub-lumen 22 with gas increases the difference in acoustic impedance between the circumferential wall 24 of the catheter body 16 and the sub-lumen 22. As a result, when an echo beam 36 is irradiated onto the catheter 10 from outside the catheter 10, the reflection intensity of the echo beam 36 at the boundary (sub-inner circumferential surface 26) between the circumferential wall 24 of the catheter body 16 and the sub-lumen 22 increases, thereby increasing the echo brightness of the reflected wave 44 of the echo beam 36. As a result, when the probe of an ultrasound device receives the reflected wave 44 of the echo beam 36 while the catheter 10 is inserted into a living body, the distal end position of the catheter 10 can be easily confirmed. Furthermore, because the catheter 10 has a simple structure in which the main lumen 20 and the sub-lumen 22 are provided in the catheter body 16, the catheter 10 can be easily manufactured using existing materials and equipment, and its biocompatibility can be ensured.

[0061] Furthermore, when the catheter 10 is inserted into a blood vessel of a living body, the position of the tip of the catheter 10 may shift due to bodily movements of the living body, and the tip of the catheter 10 may be inserted into a blood vessel other than the intended blood vessel. In this embodiment, as described above, the catheter main body 16 has the sublumen 22, so the user can easily check whether the tip of the catheter 10 has been mistakenly inserted into another blood vessel while viewing an ultrasound image. Therefore, when the user confirms that the tip of the catheter 10 has been mistakenly inserted into another blood vessel, they can reinsert the tip of the catheter 10 into the intended blood vessel.

[0062] Furthermore, when the sub-lumen 22 is positioned axially inside the catheter body 16, the user can confirm the position of the catheter 10 not only at the tip of the catheter 10 but also along the entire axial direction. This allows the user to determine the presence or absence of the catheter 10 without having to search for the tip of the catheter 10. As a result, the possibility that the user will overlook the catheter 10 can be reduced.

[0063] In medical settings, it is recommended to use an X-ray imaging device to take a fluoroscopic image of a living body and view the fluoroscopic image to confirm the position of the catheter tip within the living body's blood vessels. However, if an X-ray imaging is performed on a living body every time the living body moves, the living body must be moved to the X-ray imaging device or the X-ray imaging device must be moved close to the living body. Therefore, performing an X-ray imaging on a living body every time the living body moves is inconvenient for the user and increases the living body's exposure to X-rays.

[0064] In contrast, in this embodiment, an ultrasound image of a living body can be obtained simply by contacting the probe of the ultrasound device with the skin of the living body, and therefore, by viewing the ultrasound image, the user can easily confirm the position of the tip of the catheter 10 inserted into the blood vessel inside the living body.

[0065] 1, when the cross-sectional area of the sub-lumen 22 (the inner diameter of the sub-lumen 22) is relatively large, closing both the distal end 28 and the proximal end 32 of the sub-lumen 22 can effectively prevent the inflow of liquid into the sub-lumen 22. When the cross-sectional area of the sub-lumen 22 is relatively small, closing only the distal end 28 of the sub-lumen 22 can effectively prevent the inflow of liquid into the sub-lumen 22 due to surface tension.

[0066] Next, modified examples (first to ninth modified examples) of this embodiment will be described with reference to Figures 3A to 8. In each modified example, the same components as those of the catheter 10 according to this embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0067] As shown in FIG. 3A , in a catheter 50 according to the first modification, the catheter main body 16 further includes a plurality of uneven portions 52. The plurality of uneven portions 52 are provided on a sub-inner circumferential surface 56 that forms a sub-lumen 54. The plurality of uneven portions 52 are provided on the sub-inner circumferential surface 56 at intervals in the circumferential direction of the sub-lumen 54. As described above, the sub-lumen 54 extends in the axial direction (see FIG. 1 ), and therefore each of the plurality of uneven portions 52 also extends in the axial direction. FIG. 3A illustrates a case in which the sub-inner circumferential surface 56 has mountain-valley-shaped uneven portions 52 that are provided at equal angular intervals in the circumferential direction of the sub-lumen 54. Note that it is sufficient that at least one uneven portion 52 is provided on the sub-inner circumferential surface 56. The shape of the uneven portion 52 is not limited to a mountain-valley shape. The shape of the uneven portion 52 may be, for example, rectangular.

[0068] In this way, in the first modified example, the uneven portion 52 is provided on the sub-inner circumferential surface 56, and therefore the echo beam 36 irradiated from outside the catheter 50 is scattered by the uneven portion 52. This makes it possible to effectively increase the echo brightness of the reflected wave 44 of the echo beam 36.

[0069] In addition, in the first variant, multiple uneven portions 52 are provided at intervals around the circumference of the sub-lumen 54 on the sub-inner surface 56, so that the echo beam 36 irradiated from outside the catheter 50 can be effectively scattered.

[0070] As shown in FIG. 3B , in a catheter 60 according to the second modification, the catheter main body 16 has a plurality of uneven portions 62. The plurality of uneven portions 62 are provided at uneven angular intervals in the circumferential direction of the sub-lumen 64 on a sub-inner circumferential surface 66 that forms the sub-lumen 64. FIG. 3B illustrates a case in which rectangular uneven portions 62 are provided at uneven angular intervals in the circumferential direction of the sub-lumen 64 on the sub-inner circumferential surface 66. It is sufficient that at least one uneven portion 62 is provided on the sub-inner circumferential surface 66. The shape of the uneven portion 62 is not limited to a rectangular shape. The shape of the uneven portion 62 may be, for example, a hill-valley shape.

[0071] In the second modified example, as in the first modified example (see FIG. 3A), the echo beam 36 emitted from outside the catheter 60 is scattered by the uneven portion 62, so that the echo brightness of the reflected wave 44 of the echo beam 36 can be effectively increased. Furthermore, since a plurality of uneven portions 62 are provided at intervals in the circumferential direction of the sublumen 64, the echo beam 36 emitted from outside the catheter 60 can be effectively scattered.

[0072] As shown in FIG. 4A , in a catheter 70 according to a third modification, the catheter body 16 has a plurality of sublumens 72. Each of the sublumens 72 is formed by an inner circumferential surface 74 of the peripheral wall 24 of the catheter body 16. The sublumens 72 are spaced apart inside the catheter body 16 in a direction perpendicular to the axial direction (axis 14) and perpendicular to the radial direction (left-right direction in FIG. 4A ). The inner diameter of each sublumen 72 is smaller than the inner diameters of the sublumens 22, 54, and 64 (see FIGS. 2 , 3A, and 3B ). FIG. 4A illustrates a case in which three sublumens 72 are spaced apart inside the catheter body 16 in directions perpendicular to the axial and radial directions. Note that the number of sublumens 72 is not limited to three. Two sublumens 72 or four or more sublumens 72 may be spaced apart in directions perpendicular to the axial and radial directions.

[0073] The third modified example is not limited to the configuration of Fig. 4A. The multiple sublumens 72 may be arranged at least in a direction perpendicular to the axial direction inside the catheter body 16. For example, the multiple sublumens 72 may be arranged at intervals inside the catheter body 16 in a direction perpendicular to the axial direction and intersecting the radial direction (the diagonal direction in Fig. 4A).

[0074] In the third modification, the difference in acoustic impedance between the peripheral wall 24 of the catheter body 16 and each of the sublumens 72 is increased, which effectively increases the echogenicity when the echo beam 36 is irradiated onto the catheter 70 from outside the catheter 70.

[0075] Furthermore, when the probe of the ultrasound device receives the reflected wave 44 of the echo beam 36 while the catheter 70 is inserted into a living body, the user can easily determine that the received reflected wave 44 is the reflected wave 44 of the echo beam 36 reflected at the boundary between the peripheral wall 24 of the catheter body 16 and each of the multiple sublumens 72.

[0076] As shown in FIG. 4B , the catheter body 16 of the catheter 80 according to the fourth modification also has a plurality of sublumens 72. In the fourth modification, the plurality of sublumens 72 are arranged at intervals in the direction perpendicular to the axial direction and the radial direction inside the catheter body 16. In FIG. 4B , six sublumens 72 are provided inside the catheter body 16. Inside the catheter body 16, a set of three sublumens 72 provided relatively radially outward and a set of three sublumens 72 provided relatively radially inward are provided at intervals in the radial direction. The three sublumens 72 in each set are provided at intervals in the direction perpendicular to the axial direction and the radial direction (the left-right direction in FIG. 4B ). The number of sublumens 72 is not limited to six. Two or more sublumens 72 may be provided at intervals in the direction perpendicular to the axial direction (for example, the radial direction).

[0077] Furthermore, the fourth modified example is not limited to the configuration shown in Fig. 4B. For example, the multiple sublumens 72 may be arranged at intervals inside the catheter body 16 in a direction perpendicular to the axial direction and intersecting the radial direction (the diagonal direction in Fig. 4B).

[0078] In the fourth modification, the difference in acoustic impedance between the peripheral wall 24 of the catheter body 16 and each of the sublumens 72 is increased, thereby effectively increasing the echogenicity when the echo beam 36 is irradiated onto the catheter 80 from outside the catheter 80.

[0079] Also, in the fourth variant, when the probe of the ultrasound device receives the reflected wave 44 of the echo beam 36 while the catheter 80 is inserted into a living body, the user can easily determine that the received reflected wave 44 is the reflected wave 44 of the echo beam 36 reflected at the boundary between the peripheral wall 24 of the catheter body 16 and each of the multiple sub-lumens 72.

[0080] As shown in Fig. 5A, in a catheter 90 according to a fifth modified example, the main lumen 20 is provided coaxially with the axis 14 inside the catheter body 16. In the fifth modified example, a plurality of sub-lumens 72 are provided at intervals in the circumferential direction of the main lumen 20. In Fig. 5A, two sub-lumens 72 are provided at 180° intervals in the circumferential direction of the main lumen 20 (around the axis 14) inside the catheter body 16. In other words, the two sub-lumens 72 face each other with the main lumen 20 sandwiched between them.

[0081] The fifth modification also provides the same effect as the third modification (see FIG. 4A). Furthermore, by providing two sublumens 72 at 180° intervals, one of the sublumens 72 can be positioned to face the ultrasound device when the catheter 90 is rotated about the axis 14. This makes it possible to efficiently increase echogenicity.

[0082] As shown in Fig. 5B, the catheter 100 according to the sixth modification differs from the fifth modification (see Fig. 5A) in that four sublumens 72 are provided at 90° intervals in the circumferential direction (around axis 14) of the main lumen 20. The four sublumens 72 may be provided at unequal angular intervals. Alternatively, three sublumens 72 or five or more sublumens 72 may be provided inside the catheter body 16 at equal or unequal angular intervals in the circumferential direction (around axis 14) of the main lumen 20.

[0083] The sixth modified example also provides the same effect as the third modified example (see FIG. 4A). Furthermore, by providing four sub-lumens 72 at 90° intervals, at least one sub-lumen 72 can be positioned to face the ultrasound device when the catheter 100 is rotated about the axis 14. This allows at least one sub-lumen 72 to face the ultrasound device without being hidden by the main lumen 20, making it possible to increase echogenicity more efficiently.

[0084] As shown in FIG. 6 , in a catheter 110 according to the seventh modification, the catheter main body 16 has a plurality of uneven portions 112. The plurality of uneven portions 112 are provided on a sub-inner circumferential surface 116 that forms a sub-lumen 114. The plurality of uneven portions 112 may be formed around the entire circumference of the sub-inner circumferential surface 116. Alternatively, the plurality of uneven portions 112 may be formed radially outward or radially inward of the sub-inner circumferential surface 116. The plurality of uneven portions 112 are provided at equal intervals in the axial direction. FIG. 6 illustrates a case in which a plurality of peak-valley-shaped uneven portions 112 are provided at equal intervals in the axial direction on the radially outer portion of the sub-inner circumferential surface 116. Note that the plurality of uneven portions 112 may also be provided at uneven intervals in the axial direction. Alternatively, the plurality of uneven portions 112 may be rectangular uneven portions. At least one uneven portion 112 may be provided on the sub-inner circumferential surface 116 .

[0085] The seventh modification also effectively scatters the echo beam 36 emitted from outside the catheter 110. Furthermore, since the echo brightness is effectively increased, when the catheter 110 is inserted into a living body, it becomes easy to confirm which part of the living body the catheter 110 is inserted into.

[0086] As shown in Fig. 7, in a catheter 120 according to an eighth modification, a main lumen 20 is provided coaxially with the axis 14 inside the catheter body 16. A sub-lumen 122 extends helically in the axial direction inside the catheter body 16. The sub-lumen 122 extends helically in the axial direction so as to surround the main lumen 20. Note that the sub-lumen 122 may extend helically in the axial direction so as not to surround the main lumen 20.

[0087] In the eighth modification, the echo beam 36 emitted from outside the catheter 120 can be effectively scattered by the spiral sublumen 122. This further increases the echo brightness, making it possible to easily confirm the part of the living body into which the catheter 120 has been inserted when the catheter 120 is inserted.

[0088] That is, when an echo beam 36 is irradiated onto the catheter 120 from outside the catheter 120, the echo beam 36 can be effectively scattered in the circumferential and axial directions. As a result, even if the angle of incidence of the echo beam 36 with respect to the catheter 120 changes as the catheter 120 advances while the catheter 120 is inserted into a living body, the echo beam 36 can be effectively scattered.

[0089] Furthermore, the sub-lumen 122 that extends spirally in the axial direction so as to surround the main lumen 20 can be formed using, for example, a three-dimensional modeling technique.

[0090] As shown in Fig. 8, in a catheter 130 according to the ninth modification, the catheter main body 16 has an uneven portion 132. The uneven portion 132 is provided on a sub-inner circumferential surface 136 that forms a sub-lumen 134. The uneven portion 132 is provided in a spiral pattern in the axial direction on the sub-inner circumferential surface 136. In Fig. 8, protruding uneven portions 132 are provided in a spiral pattern in the axial direction on the sub-inner circumferential surface 136. Note that in the ninth modification, recessed uneven portions 132 may also be provided in a spiral pattern in the axial direction.

[0091] In the ninth modification, the echo beam 36 irradiated from outside the catheter 130 can be effectively scattered. That is, when the echo beam 36 is irradiated onto the catheter 130 from outside the catheter 130, the echo beam 36 is scattered not only in the circumferential direction but also in the axial direction. Furthermore, the echo brightness is effectively increased. As a result, when the catheter 130 is inserted into a living body, it becomes possible to easily confirm which part of the living body the catheter 130 has been inserted into.

[0092] The sub-lumens 22, 54, 64, 72, 114, 122, 134 (see FIGS. 1 to 8) may extend in the circumferential direction of the catheter main body 16 inside the catheter main body 16. Alternatively, the sub-lumens 22, 54, 64, 72, 114, 122, 134 may extend in any direction inside the catheter main body 16. In either case, the effects of this embodiment and each of the modifications can be obtained.

[0093] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the present disclosure or the gist of the present disclosure derived from the content of the claims and their equivalents. [Explanation of symbols]

[0094] 10, 50, 60, 70, 80, 90, 100, 110, 120, 130...catheter 16...Catheter body 20...Main lumens 22, 54, 64, 72, 114, 122, 134... Sublumens

Claims

1. A catheter comprising a tubular catheter body, The catheter body includes: a main lumen that is an inner cavity extending in the axial direction of the catheter body within the catheter body, the distal end and the proximal end of which communicate with the outside of the catheter body and allow the flow of a liquid; a sub-lumen, which is another lumen extending in the axial direction or in a direction intersecting the axial direction at least at a distal end portion inside the catheter body, and which has at least a distal end closed, is filled with gas, and does not allow the inflow of the liquid; A catheter having:

2. The catheter of claim 1, The catheter body further has an uneven portion provided on a sub-inner circumferential surface that forms the sub-lumen.

3. The catheter according to claim 2, A catheter in which the uneven portion is provided on the sub-inner surface at intervals in the circumferential direction of the sub-lumen.

4. The catheter according to claim 2, A catheter in which the uneven portion is provided on the sub-inner surface at intervals in the axial direction.

5. The catheter according to claim 2, A catheter, wherein the uneven portion is provided spirally in the axial direction on the sub-inner circumferential surface.

6. The catheter according to any one of claims 1 to 5, A catheter, wherein the sub-lumen extends spirally in the axial direction inside the catheter body.

7. The catheter according to claim 6, The sub-lumen extends spirally in the axial direction so as to surround the main lumen.

8. The catheter according to any one of claims 1 to 5, A catheter wherein both the distal and proximal ends of the sublumen are occluded.

9. The catheter according to any one of claims 1 to 5, The catheter body has a plurality of the sub-lumens.

10. The catheter of claim 9, A catheter, wherein the plurality of sub-lumens are arranged inside the catheter body in a direction perpendicular to the axial direction.

11. The catheter of claim 9, A catheter, wherein the plurality of sub-lumens are arranged at intervals in the circumferential direction of the main lumen inside the catheter body.

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