Abstract:
A medical tube, which is inserted into a tubular organ and discharges and suctions fluid, is provided with a tube-shape main body which extends a prescribed length and with a valve which is disposed in a portion of the main body that is inserted into the tubular organ and can discharge or suction a fluid, wherein the valve includes multiple slits which are formed so as to extend axially of the body a prescribed length, reaching from the outer periphery to the inner periphery of the main body, and which are provided spaced in the circumferential direction of the main body. Each slit is formed tilted in the same direction with respect to a radially-extending line which passes through the axial center of the main body.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a medical tube such as a catheter which is to be indwelled in a blood vessel to administer a medical solution such as an anticancer agent, a shunt tube for draining a fluid accumulated in the brain ventricle into the abdominal cavity, or a drainage tube which is to be inserted into the bile duct or the like to drain the bile or the like. 
       BACKGROUND ART 
       [0002]    To inject a medical solution such as an anticancer agent into the main body, for example, a catheter is percutaneously inserted into a tubular organ such as a blood vessel. Thereafter, its tip end portion is moved to reach the cancer-affected portion, and the medical solution is administered from a discharge hole disposed in the tip end portion. Alternatively, the tip end of a catheter is moved to reach a central vein, and the medical solution is administered to the whole body is performed. This kind of catheter may be provided with a valve element at a discharge hole, in order to prevent the blood or the like from reversely flowing into the catheter to coagulate therein. The valve element opens when a medical solution or the like is administered, and closes in other cases is sometimes disposed. 
         [0003]    In recent clinical practice, in order to check whether a tip end portion of a catheter is placed in a blood vessel or not, a suction work of sucking blood from the tip end portion of the catheter may be required to thereby check whether the blood flows out from the base end side of the catheter or not (ONS Guidelines etc.). In order to perform the suction work, there is used a catheter also having a suction valve element. 
         [0004]    As this kind of catheter, Patent Literature 1 describes a valved catheter in which an injection hole is provided with a slit valve, and a suction hole is a provided with a flap valve. The slit valve is provided by forming a linear slit in a peripheral wall portion of the catheter. The flap valve is provided by forming an arcuate slit in the peripheral wall portion. In the catheter, when a medical solution is injected into the interior and pressurized, the slit valve opens and the medical solution is injected into a blood vessel through the injection hole. On the other hand, when the interior is depressurized, the flap valve opens, and the blood is sucked into the catheter through the suction hole. 
         [0005]    There is also known a catheter including a so-called two-way valve. In this kind of catheter, instead of providing valve elements respectively for discharge and suction as in the above-described valved catheter, the valve is configured to open both in the case where a medical solution or the like is to be discharged, and in the case where the blood or the like is to be sucked. 
         [0006]    For example, Patent Literature 2 describes a valved catheter in which a valve including an openable slit is formed in the longitudinal direction in the distal-end side of a pipe main body having a circular cross-sectional shape. One of both edge portions of the slit of the valve is made to be easily deformable than the other edge portion when a fluid is passed from the interior to the exterior through the valve and when a fluid is passed from the exterior to the interior through the valve. In this kind of catheter, when the interior is pressurized or depressurized, the one edge portion of the slit which is more easily deformable is deformed, whereby the slit is caused to open, and a medical solution is discharged or the blood is sucked. 
       CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP-A-2012-200304-A 
     Patent Literature 2: JP-A-2011-50420-A 
     SUMMARY OF INVENTION 
     Technical Problem 
       [0007]    In the valved catheter of Patent Literature 1, the valve elements are disposed respectively for discharge and suction. However, it is difficult to dispose the plural valve elements in a limited space. If the portion in which the flap valve is disposed abuts against the inner wall of the blood vessel, even when the flap valve is caused to open by depressurizing the interior of the catheter, the suction hole is closed by the inner wall of the blood vessel. Thus, the blood might not be effectively sucked into the catheter. 
         [0008]    On the other hand, in the valved catheter of Patent Literature 2, since one of both edge portions of the slit is required to be more easily deformable than the other edge portion, it is difficult to process the slit. 
         [0009]    It is an object of the invention to provide a medical tube in which discharge of a fluid such as a medical solution, and suction of a fluid such as the blood are enabled to be surely performed, by a relatively simple structure. 
       Solution to Problem 
       [0010]    In order to attain the object, the invention provides 
         [0011]    a medical tube which is to be inserted into a tubular organ or a body cavity to discharge or suck a fluid, including: 
         [0012]    a tubular main body which extends by a predetermined length; and 
         [0013]    a valve which is disposed in a portion of the main body, the portion being to be inserted into the tubular organ or the body cavity, and which is configured to discharge or suck the fluid, 
         [0014]    wherein the valve is configured by plural slits which extend by a predetermined length in an axial direction of the main body, which are formed so as to extend from an outer circumference of the main body to an inner circumference, and which are disposed at intervals in a circumferential direction of the main body, and 
         [0015]    wherein the slits are formed to be inclined in a same direction with respect to a line L that passes through an axial center C of the main body and that extends in a radial direction. 
         [0016]    The invention may preferably provide the above-mentioned medical tube, 
         [0017]    wherein angles θ of the slits with respect to the line L of the main body are 10 to 60°. 
         [0018]    The invention may preferably provide the above-mentioned medical tube, 
         [0019]    wherein R/T is 2 to 6, where an inner diameter of the main body is R and a thickness of the main body along the line L is T. 
         [0020]    The invention may preferably provide the above-mentioned medical tube, 
         [0021]    wherein axial lengths S of the slits are 1.6 to 5.0 times an outer diameter D of the main body. 
         [0022]    The invention may preferably provide the above-mentioned medical tube, 
         [0023]    wherein axial angles E of the slits with respect the axial center C of the main body are ±6°. 
       Advantageous Effects of Invention 
       [0024]    According to the invention, when a medical solution such as an anticancer agent or a nutrient is injected into the medical tube, and the interior of the main body is pressurized, wall portions of the main body which are separated from each other through the plural slits are pressed toward the outer diameter side of the main body, whereby the slits are caused to open. Therefore, the fluid can be discharged. 
         [0025]    On the other hand, when the interior of the medical tube is sucked and depressurized by a pump, a syringe, or the like, the wall portions of the main body which are separated from each other by the slits bend toward the inner diameter side of the main body. As a result, end portions which are butted against each other through the slits are strongly pressed against each other. 
         [0026]    In this case, the slits are formed to be inclined in the same direction with respect to the line L that passes through the axial center C of the main body and that extends in a radial direction. Therefore, one of the end portions which are butted against each other through the slit intersects at an acute angel with the inner circumferential surface, and at an obtuse angle with the outer circumferential surface (hereinafter, the end portion is referred to as “inner end portion”). The other one of the end portions which are butted against each other through the slit intersects at an obtuse angel with the inner circumferential surface, and at an acute angle with the outer circumferential surface (hereinafter, the end portion is referred to as “outer end portion”). 
         [0027]    When, as described above, the end portions which are butted against each other through the slit are strongly pressed against each other by the suction of the interior of the medical tube, slippage occurs between the inclined slit surfaces, the inner end portion is moved toward the inner diameter side of the medical tube, and the outer end portion is moved toward the outer diameter side of the medical tube. Therefore, the peripheral wall portions which are divided by the plural slits are moved in the inclination direction of the slits (in the direction in which the tip ends formed by the slits form an acute angle), the end portions which are butted against each other through the slits are disengaged from each other, and the slits largely open. Consequently, a fluid which exists outside the medical tube, such as a body fluid can be effectively sucked. 
         [0028]    In the medical tube, the valve is configured by the plural slits which are disposed at intervals in the circumferential direction of the main body. In the case where the main body is inserted into a tubular organ or a body cavity, even when a portion of the main body in the circumferential direction abuts against the inner wall of the tubular organ or the body cavity, and the slit(s) in the portion is closed, therefore, the other slit(s) opens, and therefore a fluid can be surely sucked into the main body. The plural slits are disposed at intervals in the circumferential direction of the main body. In the above-described operations of discharging or sucking a fluid, therefore, the pressing force caused by the fluid, or the suction force caused by a syringe or the like acts in a balanced manner on the inner surfaces of the wall portions. Therefore, the wall portions are caused to easily deform, and the slits are enabled to easily open. 
         [0029]    According to the invention, as described above, it is possible to provide a medical tube in which discharge of a fluid such as a medical solution, and suction of a fluid such as a body fluid are enabled to be surely performed, simply by forming a plural slits to be inclined in the same direction with respect to the line L that passes through the axial center C of the main body and that extends in an radial direction, at intervals in the circumferential direction of the main body. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0030]      FIG. 1  is a perspective view showing a first embodiment of the medical tube of the invention. 
           [0031]      FIGS. 2A to 2C  show the medical tube.  FIG. 2A  is an enlarged side view of main portions.  FIG. 2B  is an enlarged front view of main portions.  FIG. 2C  is a sectional view taken along arrow lines B-B in  FIG. 2B . 
           [0032]      FIG. 3  is an enlarged sectional view where the medical tube is cut along arrow lines A-A in  FIG. 2A . 
           [0033]      FIGS. 4A and 4B  show a state of the medical tube where a fluid is to be discharged to the outside of the tube.  FIG. 4A  is an enlarged sectional view of main portions in a state where slits have not yet opened.  FIG. 4B  is a sectional view of main portions in a state where the slits open. 
           [0034]      FIG. 5  is a side view of main portions of the medical tube in a state where the slits open, and the fluid is discharged to the outside of the tube. 
           [0035]      FIGS. 6A to 6C  show a state of the medical tube where the fluid is sucked into the tube.  FIG. 6A  is a sectional view of main portions in the initial state where a pressing force is applied to the slits.  FIG. 6B  is a sectional view of main portions in a state where end portions which are butted against each other through the slits begin to be displaced.  FIG. 6C  is a sectional view of main portions in a state the portions which are butted against each other through the slits are displaced from each other, the slits open, and the fluid is sucked. 
           [0036]      FIG. 7  is a side view of main portions of the medical tube showing a state where the slits open, and the fluid is sucked into the tube. 
           [0037]      FIGS. 8A and 8B  are sectional views of main portions of the medical tube illustrating the difference of the magnitudes of the angles θ of the slits with respect to a line L. 
           [0038]      FIGS. 9A and 9B  are sectional views of main portions of the medical tube illustrating the difference of the magnitudes of R/T. 
           [0039]      FIGS. 10A to 10C  show a second embodiment of the medical tube of the invention.  FIG. 10A  is a sectional view of main portions in a normal state.  FIG. 10B  is a sectional view of main portions in a state where a fluid is discharged.  FIG. 10C  is a sectional view of main portions in a state where a fluid is sucked. 
           [0040]      FIGS. 11A to 11D  show a third embodiment of the medical tube of the invention.  FIG. 11A  is a sectional view of main portions in a normal state.  FIG. 11B  is a sectional view of main portions in a state where a fluid is discharged.  FIG. 11C  is a sectional view of main portions showing a manner of sucking a fluid.  FIG. 11D  is a sectional view of main portions showing another manner of sucking a fluid. 
           [0041]      FIGS. 12A to 12C  shows a fourth embodiment of the medical tube of the invention.  FIG. 12A  is a sectional view of main portions in a normal state.  FIG. 12B  is a sectional view of main portions in a state where a fluid is discharged.  FIG. 12C  is a sectional view of main portions in a state where a fluid is sucked. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0042]    Hereinafter, a first embodiment of the medical tube of the invention will be described with reference to  FIGS. 1 to 9B . 
         [0043]    As shown in  FIG. 1 , the medical tube  10  (hereinafter, referred to as “tube  10 ”) of the embodiment is used as a catheter which is to be inserted into a blood vessel to be indwelled continuously or temporarily in the blood vessel, and which, as required, can administer an anticancer agent, a nutrient, or the like or suck a body fluid such as the blood, or which can discharge and suck a fluid. 
         [0044]    Referring also to  FIGS. 2A to 2C , the tube  10  has the cylindrical-tube-shaped main body  20  which extends by a predetermined length, and a valve  30  which is disposed in a portion of the main body  20 , the portion being to be inserted into a tubular organ, and which can discharge and suck a fluid. 
         [0045]    The tube  10  of the embodiment is configured so that, after indwelled in a predetermined place in the blood vessel, a medical solution injection port  40  is connected to a base end portion of the main body  20  (see  FIG. 1 ). The medical solution injection port  40  is configured by a container  41  which is made of a synthetic resin or the like, and a connecting portion  43  which is detachably attached to a predetermined place of the outer circumference of the container  41 . A rubber film  41   a  through which the needle of a syringe can be pierced is formed in an opening of the upper surface of the container  41 . A connection pipe  43   a  which is connected to the base end portion of the main body  20  is disposed in the connecting portion  43 . 
         [0046]    The main body  20  is made of a flexible synthetic resin such as nylon, polyethylene, polypropylene, polyvinyl chloride, polyvinyl acetate, polyurethane, polystyrene, polyamide, or silicone, or may be made of a mixture or copolymer thereof. Alternatively, the main body may be made of a fluorine resin such as polytetrafluoroethylene (PTFE), perfluoroalkoxy resin (PFA), tetra-fluoroethylene/hexa-fluoropropylene copolymer (FEP), or ethylene-tetra-fluoroethylene copolymer (ETFE), or a natural rubber. 
         [0047]    Among the above-described materials, for example, a material having the hardness, which is specified under JIS K 6253 and measured by a durometer, of 75A to 75D is preferably used, and a material having the hardness of 80A to 93A is more preferably used. 
         [0048]    Powder of BaSO 4 , Bi, W, or the like may be contained in the main body  20  to provide an X-ray opacity. The outer circumference of the main body  20  may be coated by a hydrophilic resin such as 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer, polyvinylpyrrolidone, polyethyleneglycol, or methylvinylether-maleic anhydride copolymer, and further by a physiologically active substance having a fibrinolytic activity, such as urokinase, an antimicrobial agent, pigment/dye (colorant), and the like. 
         [0049]    In the embodiment, as shown in  FIG. 2C , a tip end wall  25  is provided to close the tip end of the main body  20 . The tip end wall  25  is formed so that the middle portion is thin and the peripheral edge  25   a  of the outer circumference is thick, or has a so-called bowl-like shape (see  FIG. 2C ). A linear incision  27  is formed in the middle of the tip end wall  25  (see  FIG. 2B ). The incision  27  normally closes. When a fluid such as an anticancer agent is injected into the main body  20  and the internal pressure is raised, the incision opens to enable the fluid to be discharged. When the interior of the main body  20  is returned to the normal pressure or depressurized, the incision  27  closes, and an external fluid such as the blood is prevented from entering the interior of the main body  20 . 
         [0050]    Since the bowl-shaped concave is disposed in the tip end wall  25  of the main body  20 , and the incision  27  is disposed therein, a guide wire which is not shown can be inserted into the tube  10  through both the tip and base ends of the tube  10 . Therefore, the workability in the indwelling of the tube can be improved. 
         [0051]    In the tip end wall  25 , alternatively, the middle portion may be formed into a spherical shape or a tapered shape. The tip end wall is requested to be formed so that the middle portion is thin and the peripheral edge  25   a  of the outer circumference is thick. The incision which is formed in the tip end wall  25  may have a Y-like shape, a cross-like shape, or other shapes. 
         [0052]    As shown in  FIG. 2C , the main body  20  is configured by performing injection molding of a portion  22  in which the tip end wall  25  is disposed, extrusion molding of the other portion  24 , and joining of them. 
         [0053]    As shown in  FIGS. 2A to 2C  and  3 , the valve  30  in the embodiment is configured by a pair of slits  31 ,  31  which, in the tip end side of the main body  20 , extend by a predetermined length S (see  FIG. 2A ) in the axial direction of the main body, which are formed so as to extend from the outer circumference of the main body  20  to the inner circumference, and which are opposingly disposed at substantially regular intervals in the circumferential direction of the main body  20  (see  FIGS. 2B and 3 ). 
         [0054]    More specifically, in the portion of the main body  20  in which the slits  31  are formed, as viewed in a section perpendicular to the axial center C of the main body  20 , as shown in  FIG. 3 , the slits  31  are formed to be inclined by an angle θ in the same direction with respect to a line L that passes through the axial center C of the main body  20  and that extends in a radial direction. In the embodiment, both the slits  31 ,  31  are formed so as to be inclined in a counterclockwise direction (left-handed direction) with respect to the line L (see  FIG. 3 ). 
         [0055]    As described above, the slits  31 ,  31  are disposed in the main body  20 , and therefore the main body  20  is divided into wall portions  34 ,  35 . The slits  31  are formed to be inclined by the angle θ in the same direction with respect to the line L that passes through the axial center C of the main body  20  and that extends in a radial direction, as described above. Therefore, ones of the end portions which are butted against each other through the slits  31  are formed as inner end portions  32  intersects at an acute angel with the inner circumferential surface, and at an obtuse angle with the outer circumferential surface, and the others of the end portions which are butted against each other through the slits are formed as outer end portions  33  intersects at an obtuse angel with the inner circumferential surface, and at an acute angle with the outer circumferential surface (see the double hatched portions in  FIG. 3 ). 
         [0056]    In the invention, the slits  31  are disposed at intervals in the circumferential direction of the main body  20 . Preferably, the intervals of the slits  31  are formed so that, as viewed in a section perpendicular to the axial center C of the main body  20 , when the outer circumferential length of the predetermined wall portion which is divided by the slits is 1, the outer circumferential length of the remaining wall portion is formed at the ratio of 0.5 to 2.0. More preferably, the outer circumferential length is formed at the ratio of 0.83 to 1.20, and most preferably, at regular intervals. 
         [0057]    When a fluid such as an anticancer agent is injected into the main body  20 , and the interior is pressurized (see  FIG. 4A ), the wall portions  34 ,  35  are pressed toward the outer diameter side of the main body  20 , the slits  31 ,  31  constituting the valve  30  open, and therefore the fluid can be discharged (see  FIGS. 4B and 5 ). 
         [0058]    On the other hand, when the interior of the main body  20  is sucked and depressurized, the wall portions  34 ,  35  bend toward the inner diameter side of the main body  20  by being sucked, and the inner end portions  32  and outer end portions  33  which are butted against each other through the slits  31  of the wall portions  34 ,  35  are pressed against each other (see  FIG. 6A ). When the end portions which are butted against each other through the slits  31  are strongly pressed against each other, slippage occurs between the inclined slit surfaces, so that the inner end portions  32  are moved toward the inner diameter side of the main body  20 , and the outer end portions  33  are moved toward the outer diameter side of the main body  20  (see  FIG. 6B ). Therefore, the wall portions  34 ,  35  which are separated by the plural slits  31  are moved in the inclination direction of the slits  31  (in the direction in which the tip ends of the end portions formed by the slits  31  form an acute angle), the end portions which are butted against each other through the slits  31  are disengaged from each other, and the slits  31  largely open (see  FIGS. 6C and 7 ). Consequently, fluids which exist outside the medical tube, such as a body fluid can be effectively sucked. 
         [0059]    Preferably, the angles θ of the slits  31  with respect to the line L of the main body  20  are 10 to 60°, and more preferably 14 to 51°. 
         [0060]    This will be described with reference also to  FIGS. 8A and 8B . In the case where the angles θ are smaller than 10°, when the fluid is to be sucked, the opposed end portions  32 ,  33  of the wall portions  34 ,  35  are butted against each other to be hardly displaced from each other, and therefore the inner end portions  32  become hard to bend (see  FIG. 8A ). On the other hand, in the case where the angles θ exceed 60°, when the fluid is to be sucked, although the inner end portions  32  and outer end portions  33  which are butted against each other through the slits  31  may be displaced, the portions are hardly disengaged from each other, and therefore the slits  31  become hard to effectively open (see  FIG. 8B ). The sectional views of  FIGS. 8A and 8B  showing the main body  20  are obtained by rotating the main body  20  shown in  FIG. 3  by a predetermined angle, and substantially identical therewith (this is applicable also to  FIGS. 9A and 9B ). 
         [0061]    As shown in  FIG. 3 , when the inner diameter of the main body  20  is R, and the thickness of the main body  20  along the line L is T, preferably, R/T is 2 to 6, and more preferably 2.4 to 4.5. 
         [0062]    This will be described with reference also to  FIGS. 9A and 9B . As shown in  FIG. 9A , in the case where R/T above is smaller than 2, even though, when the fluid is to be sucked, the inner end portions  32  and outer end portions  33  which are butted against each other through the slits  31  are displaced, the inner end portions  32  and the outer end portions  33  abut against the inner circumferential surfaces of the opposite wall portions, and are not further positionally displaced. Therefore, the butting end surfaces of the inner end portions  32  and the outer end portions  33  are hardly disengaged from each other, and the slits  31  are effectively caused to hardly open. On the other hand, as shown in  FIG. 9B , in the case where R/T above exceeds 6, the slits  31  easily open (see the right figure of  FIG. 9B ). However, the thickness is smaller than the thicknesses of the tubes shown in  FIGS. 1 to 8B , and the thickness of the tube shown in  FIG. 9A , and the main body  20  is softened. 
         [0063]    As shown in  FIG. 2A , preferably, the axial lengths S of the slits  31  are 1.6 to 5.0 times the outer diameter D of the main body  20 , and more preferably 2.3 to 3.2 times. In the case where the axial lengths S are less than 1.6 times the outer diameter D of the main body  20 , the slits  31  become difficult to open, and the discharging and sucking amounts of the fluid are reduced. On the other hand, in the case where the axial lengths exceed 5.0 times, the rigidity of the main body  20  is lowered, and the closing force in the normal pressure is reduced. Thus, the biological liquid may enter the tube. 
         [0064]    In the embodiment, as shown in  FIG. 2A , the slits  31  are formed so as be parallel to the axial center C of the main body  20 . Alternatively, the slits may be inclined with respect to the axial center C of the main body  20 . 
         [0065]    As shown in  FIG. 2A , preferably, the axial angles E of the slits  31  with respect to the axial center C of the main body  20  are ±6°, and more preferably ±2°. In the case where the angles E are not within the range of ±6°, the circumferential lengths of the wall portions  34 ,  35  of the main body  20  which are divided by the slits  31  are uneven in the axial direction of the main body  20 , deforming operations of the wall portions  34 ,  35  in the operations of discharging and sucking the fluid are easily dispersed. Thus, there may be caused a variation in the discharging and sucking amounts of the fluid due to the slits  31 . 
         [0066]    Preferably, a lubricant such as graphite, molybdenum disulfide, a fluorine-containing compound, boron nitride, stearate, or silicone oil may be applied to the mating surfaces of the slits  31 . From the viewpoint of the biological compatibility, it is particularly preferable to use silicone oil. 
         [0067]    Next, an example of the method of using the thus structured tube  10  will be described. Hereinafter, a case where the tube is used as a blood vessel catheter which is to be inserted and indwelled in a blood vessel to administer a fluid such as an anticancer agent or a nutrient, or to suck the blood will be described. 
         [0068]    Firstly, a puncture needle which is not shown is thrust into the blood vessel by the well-known Seldinger technique, and a guide wire which is not shown is introduced from the base end of the puncture needle to be inserted into the blood vessel. Thereafter, the puncture needle is pulled out, and a scabbard-like sheath which is not shown is inserted into the blood vessel along the guide wire. Next, the base end of the guide wire is inserted through the incision  27  of the tip end wall  25  of the tube  10 , and the guide wire is introduced into the tube  10 . Then, the tip end of the guide wire is placed in a target place in the blood vessel, the tube  10  is inserted into the sheath along the outer circumference of the guide wire, and a tip end portion of the tube is caused to reach the target place in the blood vessel. Thereafter, the guide wire is pulled out from the tube  10 , the sheath is pulled out from the blood vessel, the connection pipe  43   a  of the medical solution injection port  40  is connected to the base end portion of the tube  10 , the skin is incised, and the medical solution injection port  40  is embedded under the skin. 
         [0069]    In this state, the needle of a syringe which is not shown is pierced through the rubber film  41   a  of the medical solution injection port  40 , and a fluid such as an anticancer agent is injected, whereby the fluid such as an anticancer agent is injected into the main body  20 . 
         [0070]    Then, the interior of the main body  20  is pressurized by the fluid injected into the main body  20  (see  FIG. 4A ), and therefore the wall portions  34 ,  35  which are separated from each other by the slits  31  are pressed toward the outer diameter side of the main body  20 . Consequently, the slits  31 ,  31  constituting the valve  30  open, and therefore the internal fluid of the main body  20  can be discharged to the outside of the main body through the slits  31  (see  FIGS. 4B and 5 ). 
         [0071]    In the tube  10 , at this time, the fluid can be discharged from the plural slits  31 , so that the fluid can be administered in a plural directions to the inner wall of the tubular organ. As a result, the influence of a very powerful medication (anticancer agent or the like) can be mitigated. 
         [0072]    In the embodiment, the incision  27  is formed in the tip end wall  25  of the main body  20 . In discharging of a fluid, therefore, the slits  31  open as described above, and also the incision  27  which normally closes is caused to open. As a result, the slits  31  and the incision  27  open in discharging of a fluid, and hence the fluid can be smoothly discharged. 
         [0073]    On the other hand, when a fluid such as the blood is to be sucked by using the tube  10 , a pump, syringe, or the like which is not shown is connected to the base end portion of the tube  10 , and the device is operated to suck the interior of the main body  20 , thereby depressurizing the interior of the tube, 
         [0074]    As described above, then, the wall portions  34 ,  35  which are divided by the slits  31  of the main body  20  bend toward the inner diameter side of the main body  20  by being sucked, the inner end portions  32  and outer end portions  33  which are butted against each other through the slits  31  of the wall portions  34 ,  35  are pressed against each other (see  FIG. 6A ), slippage occurs between the inclined slit surfaces, the inner end portions  32  are moved toward the inner diameter side of the main body  20 , and the outer end portions  33  are moved toward the outer diameter side of the main body  20  (see  FIG. 6B ). Therefore, the wall portions  34 ,  35  which are divided by the plural slits  31  are moved in the inclination direction of the slits  31  (in the direction in which the tip ends of the end portions formed by the slits  31  form an acute angle), the end portions which are butted against each other through the slits  31  are disengaged from each other, and the slits  31  largely open (see  FIGS. 6C and 7 ). Consequently, a fluid which exists outside the medical tube, such as a body fluid can be effectively sucked. 
         [0075]    In the embodiment, during the operation of sucking a fluid, the incision  27  which is formed in the tip end wall  25  of the main body  20  closes, and therefore the interior of the main body  20  can be effectively depressurized. As a result, the slits  31  are caused to smoothly open, and a fluid on the outside of the main body can be surely sucked. 
         [0076]    In the tube  10 , when the interior of the main body  20  is depressurized, the plural slits  31  open as described above. In the case where the main body  20  of the tube  10  is inserted into a tubular organ such as a blood vessel, even when a circumferential part of the main body  20  abuts against the inner wall of the tubular organ, and the slit  31  in the part is closed, therefore, the other slit  31  can be maintained in a state where the slit opens, and the fluid can be surely sucked into the main body  20 . 
         [0077]    The plural slits  31  are disposed at intervals in the circumferential direction of the main body  20 . In the above-described operation of discharging a fluid, therefore, the pressing force caused by the fluid acts in a balanced manner on the inner surfaces of the wall portions  34 ,  35  (see  FIG. 4A ). Also, in the operation of sucking a fluid, the suction force caused by a pump, a syringe, or the like acts in a balanced manner on the inner surfaces of the wall portions  34 ,  35  (see  FIG. 6A ). In the operations of discharging or sucking a fluid, consequently, the wall portions  34 ,  35  are caused to easily deform, and the slits  31  are enabled to easily open (see  FIGS. 4B and 6B ). Since the plural slits  31  are disposed in the main body  20 , the discharging and sucking amounts can be increased in the operations of discharging and sucking a fluid. 
         [0078]    In the case where the angles θ of the slits  31  with respect to the line L of the main body  20  are set to 10 to 60°, the oblique slits  31  which are inclined by the angle θ with respect to the line L allow the portions of the inner end portions  32  and the outer end portions  33  where the wall portions  34 ,  35  overlap with each other in the direction of the line L to have an adequate area. Thus, when the suction force caused by a pump, a syringe, or the like acts on the interior of the main body, the slits  31  can be therefore caused to easily open. 
         [0079]    Assuming a case where the inner diameter of the main body  20  is R, the thickness of the main body  20  along the line L is T, and R/T is 2 to 6, when the interior of the main body is sucked by a pump, a syringe, or the like, and the inner end portions  32  of the wall portions  34 ,  35  of the main body  20  bendingly deform toward the inner diameter side, the inner end portions  32  and the outer end portions  33  are completely displaced from each other, and the slits  31  can be caused to easily open. 
         [0080]    In the case where the axial lengths S of the slits  31  are 1.6 to 5.0 times the outer diameter D of the main body, the suction performance due to the slits  31  can be enhanced, while the rigidity of the main body  20  is maintained. 
         [0081]    In the case where the axial angles E of the slits  31  with respect to the axial center C of the main body  20  are ±6°, the circumferential lengths of the wall portions  34 ,  35  of the main body  20  which are separated by the slits  31  can be made substantially even in the axial direction of the main body  20 , and therefore the deforming operations of the wall portions  34 ,  35  in the operations of discharging and sucking a fluid are allowed to be performed in a balanced manner. 
         [0082]    In the case where a lubricant is applied to the mating surfaces of the slits  31 , it is possible to reduce the friction resistances of the contact surfaces between the inner end portions  32  and outer end portions  33  which are opposed to each other in the wall portions  34 ,  35  that are separated from each other by the slits  31 . When the interior of the main body  20  is depressurized, therefore, the inner end portions  32  can be easily displaced toward the inner diameter side of the main body, and the slits  31  are enabled to easily open. 
         [0083]    Although it has been described that the tube  10  of the embodiment is used as a catheter which is to be inserted into a blood vessel, the invention may be applied also to a medical tube which is used by being inserted into a tubular organ of the human body, such as the ureter, the bile duct, the trachea, or the like, for example, a shunt tube for, in treatment of hydrocephalus or the like, draining a fluid accumulated in the brain ventricle into the abdominal cavity, and a drainage tube which is used for draining the bile accumulated in the bile duct. 
         [0084]      FIGS. 10A to 10C  show a second embodiment of the medical tube of the invention. The portions which are substantially identical with those in the above-described embodiment are denoted by the same reference numerals, and their description is omitted. 
         [0085]    In the medical tube  10   a  (hereinafter, referred to as “tube  10   a ”) of the embodiment, as shown  FIG. 10A , three slits  31  are disposed at substantially regular intervals in the circumferential direction of the main body  20 , as viewing a portion where the slits  31  of the main body  20  are formed, in a section perpendicular to the axial center C of the main body  20 . Therefore, three wall portions  34 ,  35 ,  36  are formed. The slits  31  are formed so as to be inclined by the angle θ in the same direction (counterclockwise direction) with respect to the line L which passes through the axial center C of the main body  20 , and which extends in a radial direction. 
         [0086]    Also in the tube  10   a  of the embodiment, when a fluid is injected into the main body  20 , and the interior is pressurized, the wall portions  34 ,  35 ,  36  are pressed toward the outer diameter side of the main body  20 , the slits  31  open, and therefore the fluid can be discharged (see  FIG. 10A ). On the other hand, when the interior of the main body  20  is sucked and depressurized, the inner end portions  32  of the wall portions receive a suction force which is greater than that applied to the outer end portions  33  of the other wall portions, the inner end portions  32  bend so as to be displaced toward the inner diameter side with respect to the outer end portions  33 , the slits  31  open, and a fluid on the outside of the main body can be sucked into the main body  20  ( FIG. 10B ). 
         [0087]      FIGS. 11A to 11D  show a third embodiment of the medical tube of the invention. The portions which are substantially identical with those in the above-described embodiments are denoted by the same reference numerals, and their description is omitted. 
         [0088]    In the medical tube  10   b  (hereinafter, referred to as “tube  10   b ”) of the embodiment, as shown  FIG. 11A , four slits  31  are disposed at substantially regular intervals in the circumferential direction of the main body  20 , as viewing a portion where the slits  31  of the main body  20  are formed, in a section perpendicular to the axial center C of the main body  20 . Therefore, four wall portions  34  to  37  are formed. The slits  31  are formed so as to be inclined by the angle θ in the same direction (counterclockwise direction) with respect to the line L which passes through the axial center C of the main body  20 , and which extends in a radial direction. 
         [0089]    In the tube  10   b  of the embodiment, when a fluid is injected into the main body  20 , and the interior is pressurized, the wall portions  34 ,  35 ,  36  are pressed toward the outer diameter side of the main body  20 , the four slits  31  open, and therefore the fluid can be discharged (see  FIG. 11B ). 
         [0090]    On the other hand, when the interior of the main body  20  is sucked and depressurized, the wall portions bendingly deform as shown in  FIG. 11C  or  FIG. 11D . This change seems to occur in accordance with the above described R/T ratio of the tube  10   b , the axial lengths S of the slits  31 , and the like. 
         [0091]    In the case shown in  FIG. 11C , namely, the inner end portions  32  of the wall portions receive a suction force which is greater than that applied to the outer end portions  33  of the other wall portions, the inner end portions  32  bend so as to be displaced toward the inner diameter side with respect to the outer end portions  33 , the four slits  31  open, and a fluid on the outside of the main body can be sucked into the main body  20 . 
         [0092]    On the other hand, in the case shown in  FIG. 11D , when the wall portions bendingly deform, the inner end portion(s)  32  and outer end portion(s)  33  of a part of the wall portions abut against each other, and the slit(s) therebetween close(s). However, the configuration where the slits  31  are formed so as to be inclined by the angle θ in the same direction with respect to the line L which passes through the axial center C of the main body  20 , and which extends in a radial direction prevents a situation where all the end portions  32 ,  33  collide with each other, from occurring. Therefore, either of the slits  31  can be caused to open, and a fluid on the outside of the main body can be sucked. 
         [0093]      FIGS. 12A to 12C  show a fourth embodiment of the medical tube of the invention. The portions which are substantially identical with those in the above-described embodiments are denoted by the same reference numerals, and their description is omitted. 
         [0094]    In the medical tube  10   c  (hereinafter, referred to as “tube  10   c ”) of the embodiment, as shown  FIG. 12A , five slits  31  are disposed at substantially regular intervals in the circumferential direction of the main body  20 , as viewing a portion where the slits  31  of the main body  20  are formed, in a section perpendicular to the axial center C of the main body  20 . Therefore, five wall portions  34  to  38  are formed. The slits  31  are formed so as to be inclined by the angle θ in the same direction (counterclockwise direction) with respect to the line L which passes through the axial center C of the main body  20 , and which extends in a radial direction. 
         [0095]    In the tube  10   c  of the embodiment, when a fluid is injected into the main body  20 , and the interior is pressurized, the wall portions  34  to  38  are pressed toward the outer diameter side of the main body  20 , the five slits  31  open, and therefore the fluid can be discharged (see  FIG. 12B ). 
         [0096]    On the other hand, when the interior of the main body  20  is sucked and depressurized, the inner end portions  32  and outer end portions  33  of predetermined one(s) of the wall portions abut against each other, and the slit(s) therebetween close(s) as shown in  FIG. 12C . However, a fluid on the outside of the main body can be sucked through the other slit(s) which open. 
         [0097]    In the above-described embodiments, 2 to 5 slits are disposed at regular intervals in the circumferential direction of the main body constituting the medical tube. Alternatively, a larger number of slits may be disposed. In the case where the number of slits is increased, when an unintended external force is applied to the valve during the indwelling of the tube, however, the tube is easily deformed, and therefore the slits are caused to easily open. Consequently, the number of slits is preferably 2 to 4, and particularly preferably 2. 
       Examples 
       [0098]    The fluid suction performance was checked with respect to medical tubes including a vale similar to that of the invention. 
       1. Suction Test 1 
       [0099]    (1) Preparation of Samples 
         [0100]    Tubes of the dimensions and materials shown in Table 1 below were cut to a predetermined length to form the main bodies  20 , and slits  31 ,  31  which are inclined by 30° in the same direction with respect to the line L that passes through their axial center C of the main body were formed at regular intervals in the circumferential direction, whereby medical tubes of Samples 1 to 9 were prepared. The slits  31  were formed while setting the axial lengths S to 5 mm. 
         [0101]    (2) Testing Method 
         [0102]    A lubricant made of silicone was applied to the mating surfaces of the slits  31  of Samples 1 to 9, syringes were connected to the base end portions of the respective samples, the samples were inserted into a container in which a predetermined fluid was accumulated, and suctions were performed at a predetermined pressure by using the syringes, and the fluid suction performances were checked. Table 1 below shows results of the above. In Table 1, “WW” means that the suction performance was very excellent, “XX” means that the suction was excellent, and “ZZ” means that suction was impossible. 
         [0103]    (3) Test Results 
         [0104]    As a result, it was confirmed that, when R/T is high, the suction performance is excellent (see Table 1). 
         [0000]    
       
         
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                 Inner 
                 Outer 
                 Thick- 
                   
                 Suction 
               
               
                   
                   
                 Diameter 
                 Diameter 
                 ness 
                   
                 Perfor- 
               
               
                   
                 Material 
                 R (mm) 
                 D (mm) 
                 T (mm) 
                 R/T 
                 mance 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Sample 1 
                 Urethane 
                 1.12 
                 1.91 
                 0.40 
                 2.84 
                 WW 
               
               
                 Sample 2 
                   
                 1.24 
                 2.03 
                 0.40 
                 3.14 
                 WW 
               
               
                 Sample 3 
                   
                 1.29 
                 1.98 
                 0.35 
                 3.74 
                 WW 
               
               
                 Sample 4 
                   
                 1.34 
                 1.93 
                 0.30 
                 4.54 
                 WW 
               
               
                 Sample 5 
                 Silicone 
                 2.30 
                 5.50 
                 1.60 
                 1.44 
                 ZZ 
               
               
                 Sample 6 
                   
                 1.00 
                 2.00 
                 0.50 
                 2.00 
                 XX 
               
               
                 Sample 7 
                   
                 1.20 
                 2.20 
                 0.50 
                 2.40 
                 WW 
               
               
                 Sample 8 
                   
                 1.50 
                 2.50 
                 0.50 
                 3.00 
                 WW 
               
               
                 Sample 9 
                   
                 6.00 
                 8.00 
                 1.00 
                 6.00 
                 XX 
               
               
                   
               
               
                 WW: Suction was very excellent 
               
               
                 XX: Suction was excellent 
               
               
                 ZZ: Suction was impossible 
               
             
          
         
       
     
       2. Suction Test 2 
       [0105]    (1) Preparation of Samples 
         [0106]    Tubes in which the axial lengths S of the slits  31  were set to 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm were prepared with respect to Samples 1 to 9 above (see Table 2). Table 2 shows also S/D of each sample. 
         [0107]    (2) Testing Method 
         [0108]    A lubricant made of silicone was applied to the mating surfaces of the slits  31  of Samples 1 to 9, and a suction test was performed by the same method as that in Suction test 1 above. Table 2 below shows results of the above. In Table 2, “WW” means that the suction performance was very excellent, “XX” means that the suction was excellent, “YY” means that the suction was not sufficient, and “ZZ” means that suction was impossible. 
         [0109]    (3) Test Results 
         [0110]    As a result, it was confirmed that tubes in which the axial lengths S of the slits  31  are large with respect to the outer diameter D of the tube main body tend to exhibit superior suction performance (see Table 2). 
         [0000]    
       
         
               
               
             
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
             
             
               
                   
                   
               
               
                   
                 S/D, Suction performance 
               
             
          
           
               
                   
                 Material 
                 R/T 
                 S: 3 mm 
                 S: 4 mm 
                 S: 5 mm 
                 S: 6 mm 
                 S: 7 mm 
                 S: 8 mm 
                 S: 9 mm 
                 S: 10 mm 
               
               
                   
                   
               
             
          
           
               
                 Sample 1 
                 Urethane 
                 2.84 
                 1.58 
                 ZZ 
                 2.11 
                 XX 
                 2.63 
                 WW 
                 3.16 
                 WW 
                 3.68 
                 XX 
                 4.21 
                 XX 
                 4.71 
                 XX 
                 5.24 
                 XX 
               
               
                 Sample 2 
                   
                 3.14 
                 1.52 
                 ZZ 
                 2.02 
                 XX 
                 2.53 
                 WW 
                 3.03 
                 WW 
                 3.54 
                 XX 
                 4.04 
                 XX 
                 4.43 
                 XX 
                 4.93 
                 XX 
               
               
                 Sample 3 
                   
                 3.74 
                 1.48 
                 ZZ 
                 1.97 
                 XX 
                 2.46 
                 WW 
                 2.96 
                 WW 
                 3.45 
                 XX 
                 3.94 
                 XX 
                 4.55 
                 XX 
                 5.05 
                 XX 
               
               
                 Sample 4 
                   
                 4.54 
                 1.55 
                 ZZ 
                 2.07 
                 XX 
                 2.59 
                 WW 
                 3.11 
                 WW 
                 3.63 
                 XX 
                 4.15 
                 XX 
                 4.66 
                 XX 
                 5.18 
                 XX 
               
               
                 Sample 5 
                 Silicone 
                 1.44 
                 0.55 
                 ZZ 
                 0.73 
                 ZZ 
                 0.91 
                 ZZ 
                 1.09 
                 ZZ 
                 1.27 
                 ZZ 
                 1.45 
                 YY 
                 1.64 
                 XX 
                 1.82 
                 XX 
               
               
                 Sample 6 
                   
                 2.00 
                 1.50 
                 ZZ 
                 2.00 
                 XX 
                 2.50 
                 XX 
                 3.00 
                 XX 
                 3.50 
                 XX 
                 4.00 
                 XX 
                 4.50 
                 XX 
                 5.00 
                 XX 
               
               
                 Sample 7 
                   
                 2.40 
                 1.36 
                 ZZ 
                 1.82 
                 XX 
                 2.27 
                 WW 
                 2.73 
                 WW 
                 3.18 
                 XX 
                 3.64 
                 XX 
                 4.09 
                 XX 
                 4.55 
                 XX 
               
               
                 Sample 8 
                   
                 3.00 
                 1.20 
                 ZZ 
                 1.60 
                 XX 
                 2.00 
                 WW 
                 2.40 
                 WW 
                 2.80 
                 XX 
                 3.20 
                 XX 
                 3.60 
                 XX 
                 4.00 
                 XX 
               
               
                 Sample 9 
                   
                 6.00 
                 0.38 
                 ZZ 
                 0.50 
                 XX 
                 0.63 
                 XX 
                 0.75 
                 XX 
                 0.88 
                 XX 
                 1.00 
                 XX 
                 1.13 
                 XX 
                 1.25 
                 XX 
               
               
                   
               
               
                 WW: Suction was very excellent 
               
               
                 XX: Suction was excellent 
               
               
                 YY: Suction was not sufficient 
               
               
                 ZZ: Suction was impossible 
               
             
          
         
       
     
       3. Suction Test 3 
       [0111]    (1) Preparation of Samples 
         [0112]    Sample Nos. 1 to 7 were prepared with respect to a medical tube having the material, inner diameter R, outer diameter D, and thickness T which are identical with those of Sample 11 in Suction test 1 above, while setting the angles θ of the two slits  31 ,  31  with respect to the line L of the main body  20 , to the angles (°) shown in Table 3 below. In Table 3, Angle X1 means the angle θ in the right portion of  FIG. 3 , and Angle X2 means the angle θ in the left portion of  FIG. 3 . In all the slits  31 , the axial length S is 5 mm. 
         [0113]    (2) Testing Method 
         [0114]    A lubricant made of silicone was applied to the mating surfaces of the slits  31  of Sample Nos. 1 to 7, and a suction test was performed by the same method as that in Suction test 1 above. Table 3 below shows results of the above. In Table 3, “XX” means that the suction was excellent, and “YY” means that the suction was not sufficient. 
         [0115]    (3) Test Results 
         [0116]    As a result, it was confirmed that, in all Sample Nos. 1 to 7, the suction performance is excellent (see Table 3). 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                 Sample 
                 Angle 
                 Angle 
                 Average 
                 Suction 
               
               
                 No. 
                 X1 (°) 
                 X2 (°) 
                 Angle (°) 
                 performance 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 15 
                 15 
                 15 
                 XX 
               
               
                 2 
                 19 
                 26 
                 23 
                 XX 
               
               
                 3 
                 20 
                 20 
                 20 
                 XX 
               
               
                 4 
                 30 
                 30 
                 30 
                 XX 
               
               
                 5 
                 31 
                 43 
                 37 
                 XX 
               
               
                 6 
                 36 
                 47 
                 42 
                 XX 
               
               
                 7 
                 48 
                 48 
                 48 
                 XX 
               
               
                   
               
               
                 WW: Suction was very excellent 
               
               
                 YY: Suction was not sufficient 
               
             
          
         
       
     
       REFERENCE SIGNS LIST 
       [0000]    
       
           10 ,  10   a ,  10   b ,  10   c  medical tube (tube) 
           20  main body 
           30  valve 
           31  slit 
           32  inner end portion 
           33  outer end portion 
           34 ,  35 ,  36  wall portion 
         C axial center of main body 
         D outer diameter of main body 
         E axial angles of slit 
         L line 
         θ angle of slit with respect to line L 
         S axial length of slit