Medical catheter

Abstract

To increase freedom of selection relating to a diameter of a tube, while securing interoperability with the conventional connector.SOLUTION: A connector 10 is provided at a base end of a flexible hollow light guide tube 50. The connector 10 includes a hollow cylindrical member 21. The tube 50 is inserted into the connector 10 so as to expose the base end face 51 of the tube 50 to the tip of the cylindrical member 21. The tube 50 includes, outside the connector 10, a base diameter part 52 having a specified inside diameter. The inside diameter of the tube 50 at the base end face 51 is different from the inside diameter of the base diameter part 52.SELECTED DRAWING: Figure 2B

Description

Technical Field

[0001] The present invention relates to a medical catheter provided with a connector at the proximal end of a light guide tube.

Background Art

[0002] In the medical field, for examinations and treatments, it may be necessary to insert a flexible hollow tube into a patient. For example, in order to supply a liquid nutrient from the outside to a patient who has difficulty chewing and swallowing, enteral nutrition is performed in which the nutrient is directly sent to the stomach through a tube inserted through the mouth or nose. In enteral nutrition, prior to sending in the nutrient, it is necessary to confirm that the tip of the tube is located in the stomach.

[0003] Patent Document 1 describes a tip position detection system for a medical tube that uses the tube itself as an optical path. Specifically, with the tube inserted into the patient, light is made to enter the proximal end face of the tube and is emitted from the tip of the tube. By observing this light from outside the body, the position of the tube tip is confirmed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In enteral nutrition, in order to form a flow path through which the nutrient flows from the container in which the nutrient is stored to the stomach, it is necessary to provide a connector at the proximal end of the tube. The connector is desirably compatible with the connectors used in conventional enteral nutrition.

[0006] In Patent Document 1, the base end face of the tube into which light is incident is arranged substantially flush with the tip of the cylindrical member (male member) of the connector (FIGS. 2A and 2B of Patent Document 1). In this configuration, the opening diameter of the flow path at the tip of the cylindrical member (hereinafter referred to as the "tip opening diameter") matches the inner diameter of the tube. In order to ensure compatibility with a conventional connector regarding the tip opening diameter, it is necessary to use a tube having the same inner diameter as the tip opening diameter of the conventional connector. Therefore, there is a problem that the degree of freedom in selecting the diameter of the tube is low.

[0007] An object of the present invention is to improve the degree of freedom in selecting the diameter of a tube while ensuring compatibility with a conventional connector in a medical catheter in which a connector is provided at the base end of a light guide tube.

Means for Solving the Problems

[0008] The medical catheter of the present invention includes a flexible hollow light guide tube and a connector provided at the base end of the light guide tube. The connector includes a hollow cylindrical member. The light guide tube is inserted into the connector such that the base end face of the light guide tube is exposed at the tip of the cylindrical member. The light guide tube includes a base diameter portion having a constant inner diameter outside the connector. The inner diameter of the light guide tube at the base end face is different from the inner diameter of the base diameter portion.

Effects of the Invention

[0009] In the present invention, it is possible to arbitrarily select the inner diameter of the base diameter portion while setting the inner diameter of the base end face of the light guide tube to be the same as the tip opening diameter of a conventional connector. Therefore, according to the present invention, it is possible to improve the degree of freedom in selecting the diameter of the tube while ensuring compatibility with a conventional connector.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

[0011] In one aspect of the present invention, the light guiding tube may further include a reduced-diameter portion that extends from the proximal end face and has a constant inner diameter, and a diameter-changing portion where the inner diameter changes between the base-diameter portion and the reduced-diameter portion. Such a tube can be manufactured relatively easily.

[0012] In one aspect of the present invention, the inner diameter of the light guiding tube may change within the connector. According to such an aspect, it is possible to make the strength of the tube substantially constant in its longitudinal direction outside the connector. This is advantageous for suppressing the occurrence of kinks where the flow path is blocked by the tube bending.

[0013] In one aspect of the present invention, the inner diameter of the light guiding tube may change outside the connector. According to such an aspect, within the connector, it is possible to make the outer diameter as well as the inner diameter of the tube constant. This is advantageous for simplifying the shape of the connector.

[0014] In one aspect of the present invention, the outer diameter of the light guiding tube may be constant within the cylindrical member. Such an aspect is advantageous for improving the molding accuracy of the cylindrical member (especially its outer peripheral surface).

[0015] In one aspect of the present invention, the base end surface of the light guide tube may form a plane common to the tip of the cylindrical member. This is advantageous for ensuring compatibility with conventional connectors.

[0016] In one aspect of the present invention, the connector may further include a hollow cylindrical base tube arranged coaxially with the cylindrical member. The light guide tube may be led out from the base tube. According to such an aspect, firstly, the base tube can be used to adhesively fix the tube to the connector, and secondly, since the operator can grip the connector with the base tube, contamination of the cylindrical member by the operator's finger or the like can be prevented.

[0017] In one aspect of the present invention, the connector may further include an outer cylinder surrounding the cylindrical member and a female thread provided on an inner peripheral surface of the outer cylinder facing the cylindrical member. According to such an aspect, the connector of the present invention can be configured to have compatibility with a male connector provided at the base end of a conventional nasal tube used in enteral nutrition.

[0018] Hereinafter, the present invention will be described in detail while showing preferred embodiments. However, it goes without saying that the present invention is not limited to the following embodiments. Each of the drawings referred to in the following description shows, for the sake of convenience of explanation, the main members constituting the embodiments of the present invention in a simplified manner. Therefore, the present invention may include any members not shown in the following drawings. Also, within the scope of the present invention, the members shown in the following drawings can be changed or omitted. In the drawings cited in the description of each embodiment, members corresponding to the members shown in the drawings cited in the preceding embodiment are given the same reference numerals as those given in the drawings of the preceding embodiment. For such members, duplicate explanations are omitted, and the description of the preceding embodiment should be appropriately referred to.

[0019] In the present invention, the "axis" of a member (e.g., a connector, a cylindrical member) means the central axis of the member. The "axis" passes through the center of a circle included in the member and / or coincides with the central axis of a cylinder or a cone (taper) included in the member. The direction along a straight line orthogonal to the axis is called the "radial direction". In the radial direction, the side closer to the axis is called the "inner" side, and the side farther from the axis is called the "outer" side. The direction of rotation around the axis is called the "circumferential direction".

[0020] (Embodiment 1) An embodiment in which the present invention is applied to nasogastric tube feeding will be described. As shown in FIG. 1, a medical catheter (hereinafter simply referred to as a "catheter") 1 according to Embodiment 1 of the present invention includes a flexible hollow light guide tube (hereinafter simply referred to as a "tube") 50 and a connector 10 provided at the proximal end of the tube 50. The tube 50 is inserted from the nasal cavity of the patient 90, and the distal end 55 of the tube 50 reaches the stomach 91. The tube 50 has flexibility that allows it to be freely bent and deformed. The tube 50 is a hollow cylindrical object in which a continuous flow path 59 (see FIG. 2B described later) is formed over its entire length. The flow path 59 communicates with the outside of the tube 50 at both longitudinal ends of the tube 50 (i.e., the proximal end and the distal end 55). When performing tube feeding, a liquid nutrient is administered to the stomach 91 of the patient through the flow path 59 of the tube 50. The connector 10 can be repeatedly connected to and disconnected from the light source device 70. When the connector 10 is connected to the light source device 70, light from a light source 78 (see FIG. 3 described later) built into the light source device 70 passes through the tube 50 and is emitted from the distal end 55 of the tube 50. The light from the distal end 55 passes through the body of the patient 90 and causes the body surface to emit light. The operator can confirm the position of the distal end 55 of the tube 50 from the light emission position on the body surface of the patient 90.

[0021] FIG. 2A is a perspective view of the connector 10 provided at the proximal end of the tube 50. FIG. 2B is a cross-sectional view of the connector 10 along a plane including the axis (not shown) of the connector 10. The connector 10 includes a connector portion 20 on its distal end side (the upper end of the connector 10 in FIGS. 2A and 2B) and a base tube 30 on its proximal end side. The connector portion 20 includes a cylindrical member (a male member in the first embodiment) 21 having a hollow cylindrical shape and an outer cylinder 27 surrounding the cylindrical member 21. The base tube 30 has a hollow cylindrical shape. The connector portion 20 (or the cylindrical member 21) and the base tube 30 are coaxially arranged. A through hole 11 penetrates the connector 10 along the axis of the connector 10 from the cylindrical member 21 to the base tube 30. The inner diameter of the through hole 11 changes within the connector 10 such that the inner diameter on the distal end side (the upper end of the cylindrical member 21 in FIGS. 2A and 2B) of the cylindrical member 21 is smaller than the inner diameter on the distal end side (the lower end of the base tube 30 in FIGS. 2A and 2B) of the base tube 30. Specifically, an inner diameter changing portion 14 in which the inner diameter of the through hole 11 changes in a substantially tapered shape (or a substantially conical surface shape) is provided in the base tube 30. The through hole 11 includes a small inner diameter portion 13 having a relatively small and constant inner diameter on the distal end side (the cylindrical member 21 side) of the connector 10 with respect to the inner diameter changing portion 14, and a reference inner diameter portion 12 having a relatively large and constant inner diameter on the proximal end side (the base tube 30 side) of the connector 10 with respect to the inner diameter changing portion 14.

[0022] On the outer peripheral surface of the cylindrical member 21, a male tapered surface 23 whose outer diameter becomes smaller as it approaches the distal end of the cylindrical member 21 is provided. The outer peripheral surface of the cylindrical member 21 further has a distal end tapered surface 24 having a larger taper angle than the male tapered surface 23 on the side closer to the distal end than the male tapered surface 23. The distal end of the cylindrical member 21 (a part or all of the distal end tapered surface 24) protrudes in the axial direction of the connector 10 from the distal end of the outer cylinder 27. The fact that the cylindrical member 21 protrudes more than the outer cylinder 27 is advantageous for facilitating the connection of the connector 10 (or the connector portion 20) to a female connector (not shown. See FIGS. 5A and 5B of Patent Document 2, for example).

[0023] The flange 26 protrudes radially outward from the proximal end of the cylindrical member 21. From the circular outer peripheral edge of the flange 26, the outer cylinder 27 extends toward the same side as the cylindrical member 21 (the tip side of the connector 10). The outer cylinder 27 has a substantially cylindrical shape and is arranged coaxially with the cylindrical member 21. The outer cylinder 27 is radially spaced apart from the cylindrical member 21. A female thread 28 is provided on the inner peripheral surface of the outer cylinder 27 facing the cylindrical member 21.

[0024] The connector portion 20 is preferably configured to be compatible with a male connector (see, for example, FIGS. 4A and 4B of Patent Document 2) used in enteral nutrition.

[0025] The material of the connector 10 is not limited, but it is preferably made of a material having a mechanical strength (rigidity) such that it is not substantially deformed by an external force. As such a material, for example, resin materials such as polypropylene, acrylonitrile-butadiene-styrene copolymer, polycarbonate, polyacetal, polystyrene, polyamide, polyethylene, and rigid polyvinyl chloride can be used. The connector 10 can be integrally formed as a single part by an injection molding method or the like using the above resin material.

[0026] The flexible hollow tube 50 is inserted into the through hole 11 of the connector 10. The inner cavity of the tube 50 that is continuous over the entire length of the tube 50 (see FIG. 1) constitutes the flow path 59 of the tube 50 (and further the catheter 1). The diameter of the tube 50 (in the present invention, the "diameter" of the tube 50 includes both the inner diameter and the outer diameter of the tube 50 unless otherwise specified) is not constant over the entire length of the tube 50. Specifically, the tube 50 includes a base diameter portion 52, a diameter change portion 54, and a small diameter portion (different diameter portion) 53 in order from the tip 55 (see FIG. 1) side toward the proximal end side. The diameters (inner diameter and outer diameter) of each of the base diameter portion 52 and the small diameter portion 53 are constant in the longitudinal direction of the tube 50, but the small diameter portion 53 has a smaller diameter than the base diameter portion 52. In the diameter change portion 54, due to the difference in diameter between the base diameter portion 52 and the small diameter portion 53, the diameter (inner diameter and outer diameter) changes in a substantially tapered shape (or substantially conical surface shape).

[0027] The material of the tube 50 is not limited, but preferably has flexibility and light-guiding properties. For example, resins such as polyurethane, acrylic, silicone, polyethylene, styrene-based elastomer, polybutadiene, and polyolefin can be used.

[0028] The tube 50 is preferably configured as a continuous single part made of the same material over the entire length of the tube 50 from the end face (base end face) 51 on the base end side to the tip 55 (see FIG. 1). Most of the tip 55 side of the entire length of the tube 50 is a base diameter portion 52 having a constant diameter (inner diameter and outer diameter). A diameter change portion 54 and a small diameter portion 53 having a diameter different from that of the base diameter portion 52 are provided in the vicinity of the base end of the tube 50. There is no limitation on the method of forming portions with different diameters in the tube 50. As an example, a heat forming method can be used in which the vicinity of the base end of a tube cut to a predetermined length and having a constant diameter (for example, the same diameter as the base diameter portion 52) is formed into a predetermined shape using a heated mold and then immediately quenched. As another example, a method similar to blow molding can be used in which air is blown into the inside while continuously extruding the heated and melted tube material from a die in a tube shape and expanding it so as to adhere to the inner surface of a die having a predetermined shape.

[0029] A tube 50 having a base diameter portion 52, a diameter change portion 54, and a small diameter portion 53, and a connector 10 are each manufactured separately. Thereafter, the tube 50 is inserted into the through hole 11 of the connector 10 from the base end side (the small diameter portion 53 side) of the connector 10 with the base end side (the base tube 30 side) of the tube 50 leading. The small diameter portion 53, the diameter change portion 54, and the base diameter portion 52 of the tube 50 are respectively fitted into the small inner diameter portion 13, the inner diameter change portion 14, and the reference inner diameter portion 12 of the connector 10. Preferably, the outer peripheral surface of the tube 50 is in substantial contact with the inner peripheral surface of the through hole 11 of the connector 10 without a gap over the entire length of the through hole 11. The tube 50 is fixed to the connector 10 (particularly the base tube 30) with an adhesive (such as a solvent adhesive) or the like so as not to separate from the connector 10. The tube 50 is led out from the base tube 30 toward the side opposite to the cylindrical member 21. The base end surface 51 of the tube 50 is an annular flat surface perpendicular to the axis of the connector 10. The base end surface 51 constitutes a single plane common to the tip (the tip of the tip tapered surface 24) of the cylindrical member 21 and is exposed toward the outside world.

[0030] In the present embodiment, the light incident from the base end surface 51 of the tube 50 passes through the tube 50 (the portion constituting the thickness of the tube 50 between the inner peripheral surface and the outer peripheral surface of the tube 50) and is emitted from the tip 55 (see FIG. 1), and the tip 55 emits light. In order to improve the brightness (luminous flux) of the tip 55, it is preferable to reduce the light loss between the base end surface 51 and the tip 55. For this purpose, it is effective to reduce the light (leakage light) emitted from the outer peripheral surface of the tube 50 to the outside world between the base end surface 51 and the tip 55. The means for reducing the leakage light is not limited, but for example, (1) smoothing the outer peripheral surface of the tube 50, (2) covering the outer peripheral surface of the tube 50 with a coating material having a lower refractive index than the tube 50, (3) providing a reflective layer (such as a metal vapor deposition layer of silver, aluminum, etc.) on the outer peripheral surface of the tube 50, (4) configuring the tube 50 with a multilayer structure including at least a high refractive index inner layer and a low refractive index outer layer, etc., and one or a combination of two or more of them can be adopted.

[0031] Regardless of the orientation of the tip 55 within the stomach 91 (see FIG. 1), in order to cause the body surface of the patient 90 to emit light with the light from the tip 55, it is preferable that the light be emitted radially from the tip 55 of the tube 50 in a direction perpendicular or oblique to the longitudinal direction of the tube 50. To achieve this, it is preferable to provide an inclined light-emitting surface at the tip 55 of the tube 50, and / or to provide a reflecting member or a refracting member facing the light-emitting surface of the tip 55 of the tube 50, and the like.

[0032] FIG. 3 is a cross-sectional view of the catheter 1 connected to the light source device 70. The light source device 70 includes a holding portion 71 that houses and holds the connector 10 (particularly the connector portion 20), and a light source 78 disposed at a position deeper than the holding portion 71. The holding portion 71 includes a holding cylinder 72 and a stepped surface 73. The inner peripheral surface of the holding cylinder 72 is a cylindrical surface having substantially the same diameter as the outer cylinder 27. The stepped surface 73 is provided so as to project radially inward from the inner peripheral surface of the holding cylinder 72 at a position at a predetermined distance from the open end of the holding cylinder 72. The light source 78 is disposed coaxially with the holding portion 71 (or the holding cylinder 72). The connector 10 (or the connector portion 20) is inserted into the holding portion 71 until the tip of the outer cylinder 27 abuts against the stepped surface 73. The holding cylinder 72 positions the connector 10 (or the tubular member 21) coaxially with the light source 78. The stepped surface 73 positions the connector 10 (or the tubular member 21) at a position at a predetermined axial distance from the light source 78. The tip of the tubular member 21 (or the base end surface 51 of the tube 50) faces the light source 78.

[0033] The light source 78 emits light toward the tip of the tubular member 21. The light emitted from the light source 78 enters the base end surface 51 of the tube 50.

[0034] As the light source 78, although not limited, a light emitting diode (LED) can be used. The light emitted by the light source 78 is preferably visible light or near-infrared light. The wavelength of the light is not limited, but is preferably 360 nm or more, more preferably 630 nm or more, and preferably 3000 nm or less, more preferably 780 nm or less. The light with a wavelength in this range has a high transmittance to the human body, is minimally invasive to the human body, and has high safety. Since visible light can be observed with the naked eye, the position of the tip 55 of the tube 50 can be easily confirmed. Near-infrared light has better light transmittance than visible light and can be observed through a dedicated camera such as an infrared camera. In one example, light with a wavelength of 630 nm can be used as visible light, or light with a wavelength of 780 nm can be used as near-infrared light. The light source 78 may be provided with a lens so that the light emitted from the light source 78 efficiently enters the base end surface 51 of the tube 50, and / or a lens may be provided between the light source 78 and the cylindrical member 21 (or the base end surface 51).

[0035] The usage method of the catheter 1 of the first embodiment will be described.

[0036] Prepare the catheter 1 provided with the connector 10 at the base end of the tube 50. Similar to a general nasal catheter, insert the tube 50 into the nasal cavity of the patient 90 (see FIG. 1). Connect the connector 10 to the light source device 70 and cause the light source 78 (see FIG. 3) to emit light. The light emitted from the light source 78 enters the base end surface 51 of the tube 50, passes through the tube 50, and is radiated from the tip 55. The light from the tip 55 passes through the patient 90. The operator can confirm the position of the tip 55 from the light emission position on the body surface of the patient 90. The light can be confirmed with the naked eye or through an infrared camera depending on its wavelength.

[0037] Similar to the case of inserting a general nasal catheter, the tube 50 with a stylet (sometimes called a guide wire) inserted into the flow path 59 in advance may be inserted into the patient 90. The base end of the stylet can be led out from the connector 10. In this case, after pulling out the stylet from the tube 50, connect the connector 10 to the light source device 70.

[0038] The tube 50 with the optical fiber inserted into the flow path 59 so that the tip of the optical fiber reaches the tip 55 of the tube 50 may be inserted into the patient 90. Using the light source device 70, in addition to the tip 55, the tip of the optical fiber is also caused to emit light. Since the light beam from the tip 55 increases, the position of the tip 55 can be confirmed more accurately. After confirming that the tip of the tube 50 has reached the stomach, the optical fiber is pulled out from the tube 50.

[0039] After confirming that the tip 55 of the tube 50 has reached the stomach, the light source device 70 is separated from the connector 10. Then, the connector 10 is connected to a connector (female connector. See FIGS. 5A and 5B of Patent Document 2, for example) provided at the downstream end of a tube (generally called a trans-tracheal nutrition set) for transporting a nutrient solution. The nutrient solution passes through the flow path 59 of the tube 50, flows out from the tip 55, and is administered to the patient.

[0040] The connector 10, together with the tube 50, is left in the patient 90 for several days. During this period, the tube 50 may curl up or the like and the tip 55 may move. Therefore, at regular intervals (for example, immediately before administering the nutrient solution to the patient 90), the connector 10 is connected to the light source device 70, the tip 55 is caused to emit light, and its position is confirmed.

[0041] As described above, in the first embodiment, the base end surface 51 of the light-transmissive tube 50 is exposed at the tip of the cylindrical member 21 of the connector 10. Therefore, when the light of the light source 78 is radiated toward the tip of the cylindrical member 21, the light enters the base end surface 51 of the tube 50, passes through the tube 50, and exits from the tip 55. By using the tube 50 itself as an optical path, the tip 55 of the tube 50 can be caused to emit light. The light from the tip 55 can be observed through the body of the patient 90. Therefore, the position of the tip 55 of the tube 50 can be detected easily and accurately.

[0042] The connector part 20 of the connector 10 can be configured to be compatible with a male connector (hereinafter referred to as "existing male connector", see, for example, FIGS. 4A and 4B of Patent Document 2) provided at the proximal end of a tube constituting a conventional enteral nutrition catheter. In this case, the connector 10 (particularly the connector part 20) can be connected to a female connector (see, for example, FIGS. 5A and 5B of Patent Document 2) that can be connected to the existing male connector in the same manner as connecting the existing male connector to the female connector.

[0043] There may be standards regarding the shape and the like for the existing male connector. In order to ensure compatibility with the existing male connector, the opening diameter of the flow path (hereinafter referred to as "tip opening diameter") at the tip of the cylindrical member 21 needs to be the same as that of the existing male connector. In the first embodiment, the tip opening diameter depends on the flow path 59 of the tube 50 inserted into the through hole 11, rather than the through hole 11 of the cylindrical member 21. More specifically, the tip opening diameter depends on the inner diameter of the flow path 59 at the small-diameter part 53 of the tube 50. If the inner diameter of the small-diameter part 53 that defines the tip opening diameter of the flow path 59 is made the same as the tip opening diameter of the flow path of the existing male connector, compatibility with the existing male connector can be ensured with respect to the tip opening diameter. The base-diameter part 52 that occupies most of the total length of the tube 50 may have an inner diameter different from that of the tip opening diameter, that is, the small-diameter part 53. Therefore, the catheter 1 of the first embodiment can improve the degree of freedom in selecting the diameter of the tube 50 while ensuring compatibility with the existing male connector. For example, if a tube 50 having a small-diameter part 53 and a diameter-changing part 54 formed such that the small-diameter part 53 has the same inner diameter as the tip opening diameter of the existing male connector is used in the vicinity of the proximal end of a tube having a desired constant diameter over the entire length, compatibility with the existing male connector can be ensured.

[0044] In the first embodiment, the base-diameter part 52 of the tube 50 has an inner diameter larger than the tip opening diameter of the flow path 59. This is advantageous for increasing the cross-sectional area of the flow path 59 over most of the total length of the tube 50 and improving the fluidity of the nutrient flowing through the flow path 59.

[0045] (Second Embodiment) FIG. 4 is a cross-sectional view of the proximal end portion of the catheter 2 according to Embodiment 2 of the present invention. Similar to the catheter 1 of Embodiment 1, the catheter 2 includes a flexible hollow light guide tube 50 and a connector 10 provided at the proximal end of the tube 50. Embodiment 2 is different from Embodiment 1 with respect to the inner diameter of the through hole 11 of the connector 10 and the diameter of the proximal end portion of the tube 50.

[0046] The inner diameter of the through hole 11 of the connector 10 changes within the connector 10 such that the inner diameter on the distal end side of the cylindrical member 21 is larger than the inner diameter on the distal end side of the base tube 30. Specifically, an inner diameter changing portion 214 in which the inner diameter of the through hole 11 changes in a substantially tapered shape (or a substantially conical surface shape) is provided in the base tube 30. The through hole 11 includes a large inner diameter portion 213 having a relatively large and constant inner diameter on the distal end side (cylindrical member 21 side) of the connector 10 with respect to the inner diameter changing portion 214, and a reference inner diameter portion 212 having a relatively small and constant inner diameter on the proximal end side (base tube 30 side) of the connector 10 with respect to the inner diameter changing portion 214.

[0047] The tube 50 includes a base diameter portion 252, a diameter changing portion 254, and a large diameter portion (different diameter portion) 253 in order from the distal end 55 (see FIG. 1) side toward the proximal end side. The diameters (inner diameter and outer diameter) of each of the base diameter portion 252 and the large diameter portion 253 are constant in the longitudinal direction of the tube 50, but the large diameter portion 253 has a larger diameter than the base diameter portion 252. In the diameter changing portion 254, the diameter (inner diameter and outer diameter) changes in a substantially tapered shape (or a substantially conical surface shape) due to the difference in diameter between the base diameter portion 252 and the large diameter portion 253.

[0048] Similar to Embodiment 1, in this Embodiment 2 as well, the tube 50 and the connector 10 are each manufactured separately. After that, in this Embodiment 2, the tube 50 is inserted into the through-hole 11 of the connector 10 from the tip side (the base diameter portion 252 side) of the tube 50, starting from the tip side (the cylindrical member 21 side) of the connector 10. The large diameter portion 253, the diameter change portion 254, and the base diameter portion 252 of the tube 50 are respectively fitted into the large inner diameter portion 213, the inner diameter change portion 214, and the reference inner diameter portion 212 of the connector 10. Preferably, over the entire length of the through-hole 11, the outer peripheral surface of the tube 50 is in substantial contact with the inner peripheral surface of the through-hole 11 of the connector 10 without a gap. The tube 50 is fixed to the connector 10 (especially the base tube 30) with an adhesive (such as a solvent adhesive) or the like so as not to separate from the connector 10. The tube 50 is led out from the base tube 30 toward the side opposite to the cylindrical member 21. The base end surface 51 of the tube 50 forms the same surface as the tip of the cylindrical member 21 (the tip of the tip tapered surface 24) and is exposed toward the outside world.

[0049] The catheter 2 can be used in the same manner as the catheter 1 of Embodiment 1.

[0050] Similar to Embodiment 1, in this Embodiment 2 as well, if the inner diameter of the large diameter portion 253 that defines the tip opening diameter of the flow path 59 is made the same as the tip opening diameter of the flow path of the existing male connector, compatibility with the existing male connector can be ensured with respect to the tip opening diameter. The base diameter portion 252, which occupies most of the entire length of the tube 50, may have an inner diameter different from the tip opening diameter, that is, the large diameter portion 253. For this reason, the catheter 2 can improve the degree of freedom in selecting the diameter of the tube 50 while ensuring compatibility with the existing male connector. For example, if a tube 50 is used in which the large diameter portion 253 and the diameter change portion 254 are formed such that the large diameter portion 253 has the same inner diameter as the tip opening diameter of the existing male connector in the vicinity of the base end of the tube having a desired constant diameter over the entire length, compatibility with the existing male connector can be ensured.

[0051] In the second embodiment, the base diameter portion 252 of the tube 50 has an inner diameter smaller than the tip opening diameter of the flow path 59. The base diameter portion 252 with a small inner diameter also has a small outer diameter. The tube 50 having such a small-diameter base diameter portion 252 is useful, for example, as a pediatric nasal catheter.

[0052] The base end face 51 on which the light from the light source 78 is incident is constituted by a large diameter portion 253 having a relatively large diameter. For this reason, the base end face 51 has an area larger than the cross-sectional area of the tube 50 at the base diameter portion 252. This is advantageous for improving the brightness (light flux) at the tip 55 of the small-diameter base diameter portion 252 because more light can be made to be incident on the base end face 51.

[0053] The second embodiment is the same as the first embodiment except as described above. The description of the first embodiment is similarly applicable to the second embodiment.

[0054] (Third Embodiment) FIG. 5 is a cross-sectional view of the proximal end portion of the catheter 3 according to the third embodiment of the present invention. Similar to the catheters 1 and 2 of the first and second embodiments, the catheter 3 includes a flexible hollow light guide tube 50 and a connector 10 provided at the proximal end of the tube 50. The third embodiment is different from the first and second embodiments with respect to the inner diameter of the through hole 11 of the connector 10 and the diameter of the proximal end portion of the tube 50.

[0055] The inner diameter of the through hole 11 of the connector 10 is constant over the entire length of the through hole 11.

[0056] Similar to the first embodiment, the tube 50 includes a base diameter portion 352, a diameter change portion 354, and a small diameter portion (different diameter portion) 353 in order from the tip 55 (see FIG. 1) side toward the proximal end side. The respective diameters (inner diameter and outer diameter) of the base diameter portion 352 and the small diameter portion 353 are constant in the longitudinal direction of the tube 50, but the small diameter portion 353 has a smaller diameter than the base diameter portion 352. In the diameter change portion 354, the diameter (inner diameter and outer diameter) changes in a substantially tapered shape (or substantially conical surface shape) due to the difference in diameter between the base diameter portion 352 and the small diameter portion 353.

[0057] Similar to Embodiment 1, in this Embodiment 3 as well, the tube 50 and the connector 10 are each manufactured separately. Thereafter, the small-diameter portion 353 of the tube 50 is inserted into the through-hole 11 of the connector 10 from the proximal end side (base tube 30 side) of the connector 10. The small-diameter portion 353 of the tube 50 is fitted into the through-hole 11 of the connector 10. Preferably, over the entire length of the through-hole 11, the outer peripheral surface of the small-diameter portion 353 is in substantial contact with the inner peripheral surface of the through-hole 11 of the connector 10 without a gap. The tube 50 is fixed to the connector 10 (particularly the base tube 30) with an adhesive (e.g., a solvent adhesive) or the like so as not to separate from the connector 10. The tube 50 is led out from the base tube 30 toward the side opposite to the cylindrical member 21. The diameter-changing portion 354 is disposed outside the connector 10, in the vicinity of the connector 10 (particularly the base tube 30). The base end surface 51 of the tube 50 constitutes the same surface as the tip (the tip of the tip tapered surface 24) of the cylindrical member 21 and is exposed toward the outside world.

[0058] The catheter 3 can be used in the same manner as the catheter 1 of Embodiment 1.

[0059] Similar to Embodiment 1, in this Embodiment 3 as well, if the inner diameter of the small-diameter portion 353 that defines the tip opening diameter of the flow path 59 is made the same as the tip opening diameter of the flow path of the existing male connector, compatibility with the existing male connector can be ensured with respect to the tip opening diameter. The base-diameter portion 352 that occupies most of the entire length of the tube 50 may have an inner diameter different from the tip opening diameter, i.e., the small-diameter portion 353. For this reason, the catheter 3 can improve the degree of freedom in selecting the diameter of the tube 50 while ensuring compatibility with the existing male connector. For example, by using a tube 50 in which the small-diameter portion 353 and the diameter-changing portion 354 are formed such that the small-diameter portion 353 has the same inner diameter as the tip opening diameter of the existing male connector in the vicinity of the base end of a tube having a desired constant diameter over the entire length, compatibility with the existing male connector can be ensured.

[0060] In the third embodiment, the base diameter portion 352 of the tube 50 has an inner diameter larger than the tip opening diameter of the flow path 59. This is advantageous for increasing the cross-sectional area of the flow path 59 over most of the entire length of the tube 50 and improving the fluidity of the nutrient flowing through the flow path 59.

[0061] Unlike the first and second embodiments, the diameter (inner diameter and outer diameter) of the tube 50 changes outside the connector 10. The inner diameter of the through hole 11 of the connector 10 is constant over the entire length of the through hole 11. For this reason, the shape of the connector 10 is simple. This is advantageous for simplifying the mold shape and facilitating the manufacture of the connector 10 when the connector 10 is manufactured by injection molding.

[0062] The diameter change portion 354 where the diameter of the tube 50 changes is arranged near the connector 10 in the third embodiment. In this configuration, the ratio of the base diameter portion 352 to the entire length of the tube 50 increases. In a catheter, generally, the length of a portion of the tube having a predetermined and constant outer diameter (the base diameter portion 352 in the third embodiment) is standardized. Therefore, by arranging the diameter change portion 354 near the connector 10, it is possible to prevent the entire length of the tube from being unnecessarily long. If the tube is too long, problems such as a decrease in the fluidity of the nutrient flowing through the flow path 59, complicated handling of the tube, or an increase in the cost of the catheter may occur. In the third embodiment, the possibility of these problems occurring is low. Generally, the distance between the connector 10 and the diameter change portion 354 is not limited, but it is preferably 200 mm or less, more preferably 100 mm or less, and particularly preferably 50 mm or less. However, in the present invention, the position of the diameter change portion 354 is arbitrary. For example, the diameter change portion 354 may be arranged near the tip 55 (see FIG. 1) of the tube 50. In this case, the portion from the connector 10 to the diameter change portion 354 is constituted by a small diameter portion 353 having a constant diameter.

[0063] In Embodiment 3, the base diameter portion 352 has a diameter (inner diameter and outer diameter) larger than the distal end opening diameter. However, the present invention is not limited thereto. Similar to the tube 50 constituting the catheter 2 of Embodiment 2, the base diameter portion 352 may have a diameter (inner diameter and outer diameter) smaller than the distal end opening diameter. Such a catheter is useful as a pediatric nasal catheter with improved brightness at the distal end 55, similar to the catheter 2 of Embodiment 2.

[0064] Embodiment 3 is the same as Embodiment 1 except as described above. The description of Embodiment 1 is similarly applicable to Embodiment 3.

[0065] The above-described Embodiments 1 to 3 are merely examples. The present invention is not limited to the above-described Embodiments 1 to 3 and can be appropriately modified.

[0066] In the present invention, the tube 50 includes a base diameter portion having a constant inner diameter in the longitudinal direction of the tube 50 outside the connector 10. The inner diameter (distal end opening diameter) at the base end surface 51 of the tube 50 is different from the inner diameter of the base diameter portion. There is no limitation on the arrangement of the base diameter portion with respect to the connector 10. For example, as in Embodiments 1 and 2, a part of the base diameter portion may be housed in the connector 10. Alternatively, as in Embodiment 3, the base diameter portion may be arranged spaced apart from the connector 10.

[0067] In the present invention, the base diameter portion occupies most of the entire length of the tube 50. Specifically, it is preferable that the length of the base diameter portion is 80% or more, more preferably 85% or more, and particularly preferably 90% or more of the entire length of the tube 50.

[0068] In the present invention, the inner diameter of the tube may change in any manner between the base end surface 51 and the base diameter portion. However, preferably, the tube includes a reduced-diameter portion extending from the base end surface 51 and a diameter-changing portion whose inner diameter changes between the base diameter portion and the reduced-diameter portion. The reduced-diameter portion has a constant inner diameter in the longitudinal direction of the tube 50 and defines the inner diameter at the base end surface 51 of the tube. For example, like the small-diameter portions 53, 353 in Embodiments 1 and 3, the reduced-diameter portion may have an inner diameter smaller than that of the base diameter portion. In this case, the inner diameter of the diameter-changing portion increases from the reduced-diameter portion toward the base diameter portion. Alternatively, like the large-diameter portion 253 in Embodiment 2, the reduced-diameter portion may have an inner diameter larger than that of the base diameter portion. In this case, the inner diameter of the diameter-changing portion decreases from the reduced-diameter portion toward the base diameter portion.

[0069] In the present invention, the tube 50 may include a portion where the inner diameter changes (diameter-changing portion). The diameter-changing portion can be arranged at an arbitrary position in relation to the connector 10.

[0070] For example, like the diameter-changing portions 54, 254 in Embodiments 1 and 2, the inner diameter of the tube 50 may change within the connector 10. In this case, outside the connector 10, the inner diameter (and further the outer diameter of the tube 50) of the tube 50 can be made constant. In this configuration, it is difficult for a portion where the strength of the tube 50 is locally reduced (low-strength portion) to occur outside the connector 10. Generally, in the low-strength portion, the tube 50 is likely to bend and a kink that closes the flow path 59 is likely to occur. In Embodiments 1 and 2, it is difficult for a kink to occur in the tube 50. Alternatively, like the diameter-changing portion 354 in Embodiment 3, the inner diameter of the tube 50 may change outside the connector 10.

[0071] In the present invention, the inner diameter of the tube 50 may change within the cylindrical member 21 of the connector 10. However, preferably, like in Embodiments 1 to 3, the inner diameter of the tube 50 is constant within the cylindrical member 21.

[0072] In the present invention, the outer diameter of the tube may remain constant in the longitudinal direction of the tube while only the inner diameter changes. However, preferably, the outer diameter of the tube changes corresponding to the change in the inner diameter of the tube. That is, each of the base diameter portion and the different diameter portion preferably has a constant inner diameter and outer diameter in the longitudinal direction of the tube 50, and the different diameter portion preferably has an inner diameter and an outer diameter different from those of the base diameter portion. In the diameter change portion, it is preferable that both the inner diameter and the outer diameter of the tube change so as to expand or contract from the base diameter portion toward the different diameter portion. A tube in which both the inner diameter and the outer diameter change is generally easier to manufacture than a tube in which only the inner diameter changes.

[0073] In the present invention, the portion where the outer diameter of the tube 50 changes (diameter change portion) can be arranged at an arbitrary position in relation to the connector 10. However, as in Embodiments 1 to 3, preferably, the outer diameter of the tube 50 is constant within the cylindrical member 21. Thereby, it is possible to suppress a rapid change in the wall thickness (radial dimension) of the cylindrical member 21 in the axial direction. This is advantageous for improving the forming accuracy of the cylindrical member 21 (particularly the male tapered surface 23).

[0074] In the present invention, the base end surface 51 of the tube 50 only needs to be exposed at the tip of the cylindrical member 21 of the connector. That is, the base end surface 51 of the tube 50 may protrude axially from the tip of the cylindrical member 21, or may retreat into the cylindrical member 21 from the tip of the cylindrical member 21. This is because if the base end surface 51 is exposed, light from the light source 78 can be made to enter the base end surface 51. However, preferably, as in Embodiments 1 to 3 above, the base end surface 51 of the tube 50 constitutes a single plane common to the tip of the cylindrical member 21. This is advantageous for ensuring compatibility with conventional connectors.

[0075] The connector of the present invention may not include the base tube 30. In this case, the axial dimension (total length) of the connector becomes shorter, and the connector can be miniaturized. However, preferably, as in the above Embodiments 1 to 3, the connector includes a base tube 30 coaxial with the cylindrical member 21, and the tube 50 is led out from the base tube 30. The base tube 30 has the following effects. First, the base tube 30 can be used to adhesively fix the tube to the connector. Second, since the operator can grip the connector at the base tube 30 away from the cylindrical member 21, contamination of the cylindrical member 21 by the operator's fingers or the like can be prevented.

[0076] The configuration of the connector portion 20 is not limited to the above-described Embodiments 1 to 3. For example, it is not essential that the male tapered surface 23 and the tip tapered surface 24 are provided on the outer peripheral surface of the cylindrical member 21. The tip tapered surface 24 may be omitted, and the tapered surface 23 may be extended to the tip of the cylindrical member 21. In this case, the outer diameter of the base end surface 51 of the tube 50 can be enlarged. This is advantageous for improving the brightness (luminous flux) of the tip 55 of the tube 50 because the area of the base end surface 51 is enlarged, and thereby the light incident on the base end surface 51 increases.

[0077] The connector portion 20 may not include the outer cylinder 27 provided with the female screw 28 and the flange 26.

[0078] The connection structure between the connector of the present invention and the light source device is not limited to the above-described embodiment. In the above embodiment, the base end surface 51 of the tube 50 was separated from the light source 78 (see FIG. 3), but the cylindrical member 21 or the base end surface 51 may be in direct contact with the light source 78. In this case, the stepped surface 73 can be omitted. In the above embodiment, the holding cylinder 72 of the light source device 70 was configured such that the outer cylinder 27 was fitted into the holding cylinder 72, but the present invention is not limited to this. For example, the holding cylinder 72 may be configured such that the holding cylinder 72 is inserted between the outer cylinder 27 and the cylindrical member 21. In this case, for example, the cylindrical member 21 may be fitted into the holding cylinder 72. A tapered surface (female tapered surface) that is tapered and fitted with the male tapered surface 23 of the cylindrical member 21 may be provided on the inner peripheral surface of the holding cylinder 72. A male screw that is screwed with the female screw 28 may be provided on the outer peripheral surface of the holding cylinder 72. The light source device may not include the holding cylinder 72 into which the outer cylinder 27 or the cylindrical member 21 is fitted. In this case, the connector can be connected to the light source device in a state where the tip of the outer cylinder 27 abuts against a flat surface equivalent to the stepped surface 73 provided on the light source device. The flat surface positions the connector (or the cylindrical member 21) at a position axially away from the light source 78 by a predetermined distance. The light source device that does not include the holding cylinder 72 has a simple structure and is easy to manufacture. There is no limitation on the method for maintaining the connection state of the connector to the light source device, and for example, a method using an elastic band, a method using magnetic attraction force, etc. can be arbitrarily selected.

[0079] The catheters 1 to 3 of the above-described Embodiments 1 to 3 were used for nasotracheal nutrition, but the use of the catheter of the present invention is not limited to this. The catheter of the present invention may be, for example, a catheter used for enteral nutrition other than via the nose, or a catheter used for applications other than enteral nutrition (for example, a urethral catheter or a tracheal intubation catheter). The configuration of the connector and the tube is appropriately changed according to the use of the catheter. The connector of the present invention does not have to be a male connector, and may be a female connector. In this case, the cylindrical member functions as a female member, and any male member can be inserted into and removed from the flow path 59 of the tube 50.

Industrial Applicability

[0080] The present invention can be widely used as a medical catheter to be inserted into a patient.

Explanation of Signs

[0081] 1, 2, 3 Catheter (Medical Catheter) 10 Connector 11 Through Hole 21 Cylindrical Member 27 Outer Tube 28 Female Screw 30 Base Tube 50 Tube (Light-Guiding Tube) 51 Base End Face of the Tube 52, 252, 352 Base Diameter Portion 53, 353 Small Diameter Portion (Different Diameter Portion) 253 Large Diameter Portion (Different Diameter Portion) 54, 254, 354 Diameter Change Portion 55 Tip of the Tube

Claims

1. A medical catheter comprising a flexible hollow light guide tube and a connector provided on the light guide tube, wherein the light guide tube has a proximal end at one end and a distal end at the other end, the light guide tube includes a reduced-diameter portion extending from a base end face which is an end face on the proximal end side and having a constant inner diameter, a base-diameter portion disposed on the distal end side and having a constant inner diameter different from that of the reduced-diameter portion, and a diameter-changing portion where the inner diameter changes between the reduced-diameter portion and the base-diameter portion, the connector includes a hollow cylindrical tube member having a distal end on one end side and a base tube having a hollow cylindrical shape on the other end side, and the tube member and the base tube are coaxially arranged, the proximal end of the light guide tube is inserted into the connector such that the base end face of the light guide tube is exposed at the distal end of the tube member, a medical catheter, characterized in that a part of the reduced-diameter portion, the diameter-changing portion, and the base-diameter portion of the light guide tube are housed in the connector, and the remaining part of the base-diameter portion is led out from the base tube.

2. The medical catheter according to claim 1, wherein an outer diameter of the light guide tube is constant within the tube member.

3. The medical catheter according to claim 1 or 2, wherein the base end face of the light guide tube constitutes a single plane common to the distal end of the tube member.

4. The medical catheter according to any one of claims 1 to 3, wherein the connector further includes an outer tube surrounding the tube member and a female screw provided on an inner peripheral surface of the outer tube facing the tube member.

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