Transcutaneous catheter

Abstract

To provide a percutaneous catheter capable of relieving a burden on a patient's body, reducing a pressure loss of a liquid during circulation through a circulation circuit to secure a required flow rate of the liquid, and preferably preventing tightening of a stylet when the stylet is inserted.SOLUTION: A percutaneous catheter 30 has an expansion portion 32, a shaft portion 33, and an intermediate portion 34. The expansion portion has a first reinforcing body 321 comprising wires W braided to intersect with each other. The shaft portion has a second reinforcing body 331 comprising wires braided to intersect with each other. The intermediate portion has a third reinforcing body 341 including wires braided to intersect with each other. The third reinforcing body is configured to have a braiding angle, which is an inner angle in an axial direction among angles formed by the intersecting wires, smaller than those of the first reinforcing body and the second reinforcing body.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a percutaneous catheter.

Background Art

[0002] Conventionally, for performing cardiopulmonary resuscitation, circulatory assistance, and respiratory assistance in emergency treatment, treatment by percutaneous cardiopulmonary support (PCPS) has been performed. This percutaneous cardiopulmonary support method is a method of temporarily assisting and substituting cardiopulmonary functions using an extracorporeal circulation device.

[0003] The extracorporeal circulation device includes an extracorporeal circulation circuit composed of a centrifugal pump, an artificial lung, a blood withdrawal path, a blood delivery path, etc., and performs gas exchange on the withdrawn blood and delivers it to the blood delivery path.

[0004] When performing blood circulation in this circulation circuit, the blood is circulated by the force of a pump driven by a motor. Therefore, in order to suitably perform blood circulation, reduction of pressure loss in the tubes constituting the circulation circuit is required.

[0005] However, if the inner diameter of the tube is small, the pressure loss increases and the flow rate through the circulation circuit decreases. For this reason, unless the inner diameter of the tube is made sufficiently large, the required blood circulation volume cannot be obtained.

[0006] On the other hand, if the inner diameter of the tube is increased, the outer diameter of the tube also increases. Therefore, if the inner diameter of the blood withdrawal catheter (tube) or the blood delivery catheter (tube) inserted into the patient's body is increased, the degree of invasion to the patient's body increases and the burden on the patient's body increases.

[0007] In this regard, for example, Patent Document 1 below discloses a high-performance cannula that can expand or contract the diameter by axially extending or contracting the cannula body (catheter) with a stylet. According to the high-performance cannula configured in this way, by inserting the cannula body axially with the stylet to reduce the diameter (outer diameter) and then inserting it into the living body, the degree of invasion to the patient's body is reduced. Further, after inserting the high-performance cannula into the living body, by removing the stylet, the cannula body contracts axially and the diameter (inner diameter) increases. Therefore, the pressure loss in the catheter is reduced and the required liquid flow rate can be ensured.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] In the high-performance cannula disclosed in Patent Document 1, when the stylet is inserted, there is a risk that the inserted stylet may become immovable due to clamping of the stylet near the insertion point between the proximal end and the distal end.

[0010] The present invention has been made to solve the above problems, and an object of the present invention is to provide a percutaneous catheter that can suppress the burden on the patient's body, reduce the pressure loss of the liquid circulating in the circulation circuit, ensure the required liquid flow rate, and preferably prevent clamping of the stylet when the stylet is inserted.

Means for Solving the Problems

[0011] The percutaneous catheter for achieving the above object is a percutaneous catheter that extends in the axial direction and allows blood to pass through. The percutaneous catheter includes an expandable expansion portion that extends in the axial direction, a shaft portion that extends in the axial direction and is provided on the proximal end side in the insertion direction of the expansion portion, and an intermediate portion provided between the expansion portion and the shaft portion. The expansion portion has an inner and outer diameter larger than that of the shaft portion and has a first reinforcing body, and the first reinforcing body is composed of wires braided so as to intersect. The shaft portion has an inner and outer diameter larger than that of the shaft portion and has a second reinforcing body, and the second reinforcing body is composed of wires braided so as to intersect. The intermediate portion is configured such that the inner and outer diameters gradually decrease from the expansion portion toward the shaft portion and has a third reinforcing body, and the third reinforcing body is composed of wires braided so as to intersect. The knitting angle, which is the inner angle in the axial direction among the angles formed by the intersecting wires of the first reinforcing body, is configured to be smaller than that of the second reinforcing body. The knitting angle of the third reinforcing body is smaller than the knitting angle of the second reinforcing body.

Advantages of the Invention

[0012] According to the percutaneous catheter configured as described above, since the expansion portion extends in the axial direction and has a reduced outer diameter, the percutaneous catheter can be inserted into the living body, thereby suppressing the burden on the patient's body. Further, after the percutaneous catheter is left in the living body, when the stylet is removed from the percutaneous catheter, the expansion portion contracts in the axial direction and returns to its original state. Here, since the expansion portion has an inner diameter larger than that of the shaft portion, the pressure loss in the expansion portion is reduced, and the required liquid flow rate can be ensured.

[0013] Also, when the extension part and the middle part are extended in the axial direction, the wires constituting the first reinforcing body of the extension part and the third reinforcing body of the middle part are deformed so that the inclination angle with respect to the axial direction gradually decreases. Here, since the knitting angle of the third reinforcing body, which is the inner angle in the axial direction among the angles formed by the intersecting wires, is configured to be smaller than those of the first reinforcing body and the second reinforcing body, compared with the case where the knitting angle of the third reinforcing body is larger than those of the first reinforcing body and the second reinforcing body, the inclination angle of the wires constituting the third reinforcing body with respect to the axial direction becomes smaller, and the elongation distance along the axial direction of the middle part when inserting a stylet into the percutaneous catheter becomes shorter. By shortening the elongation distance along the axial direction of the middle part when inserting a stylet into the percutaneous catheter in this way, the contraction of the middle part inward in the radial direction is suppressed, and it is possible to preferably prevent the stylet from being tightened.

[0014] Therefore, it is possible to provide a percutaneous catheter that suppresses the burden on the patient's body, reduces the pressure loss of the liquid circulating in the circulation circuit, secures the required liquid flow rate, and preferably prevents the stylet from being tightened when the stylet is inserted.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. Note that the following description does not limit the technical scope or the meaning of terms described in the claims. Also, the dimensional ratios in the drawings are exaggerated for the convenience of explanation and may be different from the actual ratios.

[0017] FIG. 1 shows a system diagram of an extracorporeal circulation device applied to a percutaneous catheter according to an embodiment of the present invention and used as a percutaneous cardiopulmonary support method (PCPS) that temporarily assists and substitutes the functions of the heart and lungs until the cardiac function recovers when the patient's heart is weakened.

[0018] According to the extracorporeal circulation device 1, it is possible to perform a veno-arterial (VA) procedure in which the pump is operated to draw blood from the patient's vein (vena cava), the artificial lung performs gas exchange in the blood to oxygenate the blood, and then this blood is returned to the patient's artery (aorta) again. This extracorporeal circulation device 1 is a device for assisting the heart and lungs. Hereinafter, the procedure of drawing blood from the patient, performing a predetermined treatment outside the body, and then sending the blood back into the patient's body is referred to as "extracorporeal circulation".

[0019] As shown in FIG. 1, the extracorporeal circulation device 1 has a circulation circuit for circulating blood. The circulation circuit includes an artificial lung 2, a centrifugal pump 3, a drive motor 4 which is a driving means for driving the centrifugal pump 3, a venous side catheter (percutaneous catheter for blood withdrawal) 5, an arterial side catheter (blood delivery catheter) 6, and a controller 10 as a control unit.

[0020] The venous side catheter (blood withdrawal catheter) 5 is inserted from the femoral vein, and the tip of the venous side catheter 5 is placed in the right atrium through the inferior vena cava. The venous side catheter 5 is connected to the centrifugal pump 3 via a blood withdrawal tube (blood withdrawal line) 11. The blood withdrawal tube 11 is a pipeline for sending blood.

[0021] The arterial side catheter (blood delivery catheter) 6 is inserted from the femoral artery.

[0022] When the drive motor 4 operates the centrifugal pump 3 according to the command SG of the controller 10, the centrifugal pump 3 can draw blood from the blood withdrawal tube 11, pass the blood through the artificial lung 2, and then return the blood to the patient P via a blood delivery tube (blood delivery line) 12.

[0023] The artificial lung 2 is disposed between the centrifugal pump 3 and the blood delivery tube 12. The artificial lung 2 performs gas exchange (oxygen addition and / or carbon dioxide removal) with respect to blood. The artificial lung 2 is, for example, a membrane type artificial lung, but particularly preferably a hollow fiber membrane type artificial lung is used. Oxygen gas is supplied to this artificial lung 2 from the oxygen gas supply unit 13 through the tube 14. The blood delivery tube 12 is a pipeline connecting the artificial lung 2 and the arterial side catheter 6.

[0024] As the blood extraction tube 11 and the blood delivery tube 12, for example, a pipeline made of a synthetic resin having high transparency such as vinyl chloride resin or silicone rubber and having elastic deformable flexibility can be used. In the blood extraction tube 11, the liquid blood flows in the V1 direction, and in the blood delivery tube 12, the blood flows in the V2 direction.

[0025] In the circulation circuit shown in FIG. 1, the ultrasonic bubble detection sensor 20 is disposed in the middle of the blood extraction tube 11. The fast clamp 17 is disposed in the middle of the blood delivery tube 12.

[0026] The ultrasonic bubble detection sensor 20 detects the bubbles mixed into the circulation circuit due to an incorrect operation of the three-way stopcock 18 or a breakage of the tube during extracorporeal circulation. When the ultrasonic bubble detection sensor 20 detects that there are bubbles in the blood sent into the blood extraction tube 11, the ultrasonic bubble detection sensor 20 sends a detection signal to the controller 10. Based on this detection signal, the controller 10 notifies an alarm by an alarm and reduces the rotation speed of the centrifugal pump 3 or stops the centrifugal pump 3. Further, the controller 10 commands the fast clamp 17 to immediately block the blood delivery tube 12 by the fast clamp 17. Thereby, it is prevented that the bubbles are sent into the body of the patient P. The controller 10 controls the operation of the extracorporeal circulation device 1 to prevent the bubbles from being mixed into the body of the patient P.

[0027] A pressure sensor is provided in the tube 11 (12, 19) of the circulation circuit of the extracorporeal circulation device 1. The pressure sensor can be attached to any one or all of, for example, the attachment position A1 of the blood extraction tube 11, the attachment position A2 of the blood supply tube 12 of the circulation circuit, or the attachment position A3 of the connection tube 19 connecting between the centrifugal pump 3 and the artificial lung 2. Thereby, when performing extracorporeal circulation on the patient P by the extracorporeal circulation device 1, the pressure sensor can measure the pressure inside the tube 11 (12, 19). Note that the attachment position of the pressure sensor is not limited to the above attachment positions A1, A2, and A3, and can be attached to any position of the circulation circuit.

[0028] <First Embodiment> Referring to FIGS. 2 to 7, a percutaneous catheter (hereinafter, may be referred to as "catheter") 30 according to the first embodiment of the present invention will be described. FIGS. 2 to 7 are diagrams for explaining the configuration of the catheter 30 according to the first embodiment. This catheter 30 is used as the venous side catheter (blood extraction catheter) 5 in FIG. 1.

[0029] As shown in FIG. 2, the catheter 30 according to the present embodiment includes a catheter tube 31 having side holes 63, a tip chip 41 disposed at the tip of the catheter tube 31 and having through holes 46 and 47, a clamp tube 37 disposed on the proximal end side of the catheter tube 31, a catheter connector 35 connecting the catheter tube 31 and the clamp tube 37, and a lock connector 36.

[0030] In this specification, the side inserted into the living body is referred to as "tip" or "tip side", and the hand side where the operator operates is referred to as "proximal end" or "proximal end side". The tip portion means a certain range including the tip (the most distal end) and its periphery, and the proximal end portion means a certain range including the proximal end (the most proximal end) and its periphery.

[0031] As shown in FIG. 3, the catheter 30 has a lumen 30A that penetrates from the tip to the base end. The through holes 46, 47 and the side holes 63 provided in the tip chip 41 are configured to be arranged at different blood extraction targets in the living body so as to efficiently perform blood extraction.

[0032] When inserting the catheter 30 into the living body, the stylet 50 shown in FIG. 2 is used. As shown in FIG. 4, the stylet 50 is inserted into the lumen 30A of the catheter 30, and the catheter 30 and the stylet 50 are inserted into the living body in a state of being integrated in advance. The method of using the catheter 30 will be described later.

[0033] Hereinafter, each configuration of the catheter 30 will be described.

[0034] As shown in FIG. 2, the catheter tube 31 has an expandable expansion portion 32, a shaft portion 33 provided on the base end side of the expansion portion 32, and an intermediate portion 34 provided between the expansion portion 32 and the shaft portion 33.

[0035] The expansion portion 32 and the intermediate portion 34 are configured to have higher stretchability than the shaft portion 33. Further, as shown in FIG. 3, the expansion portion 32 is configured to have a larger outer diameter and inner diameter than the shaft portion 33. Further, as shown in FIG. 3, the intermediate portion 34 is configured such that the inner diameter and the outer diameter gradually decrease from the expansion portion 32 toward the shaft portion 33. In other words, the intermediate portion 34 is configured in a tapered shape such that the inner diameter and the outer diameter increase toward the tip side.

[0036] The lengths of the expansion portion 32, the shaft portion 33, and the intermediate portion 34 are configured to be lengths necessary for arranging the through holes 46, 47 and the side holes 63 of the tip chip 41 at desired blood extraction targets. The length of the expansion portion 32 can be, for example, 10 to 40 cm, the length of the shaft portion 33 can be, for example, 20 to 40 cm, and the length of the intermediate portion 34 can be 3 to 4 cm.

[0037] The side holes 63 are provided in the shaft portion 33. The side holes 63 function as blood drainage holes. It is preferable to have a plurality of side holes 63 in the circumferential direction. In the present embodiment, four side holes 63 are provided in the circumferential direction. Thus, even if one side hole 63 is adsorbed to and blocked by the blood vessel wall due to blood drainage, blood drainage can be performed by the other side holes 63, so that blood circulation can be stably performed.

[0038] In the present embodiment, the blood drainage targets are two locations, the right atrium and the inferior vena cava. The catheter 30 is inserted and left in the living body such that the through holes 46, 47 of the tip chip 41 are located in the right atrium and the side holes 63 are located in the inferior vena cava.

[0039] With the through holes 46, 47 and the side holes 63 arranged at the blood drainage targets, the expansion portion 32 is arranged in the inferior vena cava, which is a relatively thick blood vessel, and the shaft portion 33 is arranged in the femoral vein, which is a relatively thin blood vessel.

[0040] Also, when the stylet 50 is inserted through the lumen 30A of the catheter 30, the highly stretchable expansion portion 32 and the intermediate portion 34 extend axially as shown in FIG. 4, and the outer diameter and the inner diameter become smaller. At this time, the outer diameter of the expansion portion 32 and the intermediate portion 34 becomes substantially the same as the outer diameter of the shaft portion 33. Since the catheter 30 is inserted into the living body with the expansion portion 32 and the intermediate portion 34 extended axially so that the outer diameter and the inner diameter become smaller, the catheter 30 can be inserted with less invasiveness.

[0041] Also, after the catheter 30 is left in the living body, when the stylet 50 is removed from the lumen 30A of the catheter 30, the expansion portion 32 and the intermediate portion 34 contract from the axially extended state, and the inner diameter becomes larger. Here, the expansion portion 32 is arranged in the inferior vena cava, which is a relatively thick blood vessel. Therefore, the outer diameter of the expansion portion 32 can be increased, and accordingly, the inner diameter can be increased.

[0042] Here, the pressure loss in the expansion part 32 is the total length of the expansion part 32 × (average) passage cross-sectional area. That is, by increasing the inner diameter of the expansion part 32, the pressure loss in the expansion part 32 is reduced. When the pressure loss in the expansion part 32 is reduced, the flow rate of the blood flowing through the circulation circuit increases. Therefore, in order to obtain a sufficient blood circulation volume, it is necessary to increase the inner diameter of the expansion part 32.

[0043] On the other hand, when the wall thickness is substantially constant, if the inner diameters of the expansion part 32, the shaft part 33, and the intermediate part 34 are increased, the outer diameter becomes larger. Therefore, when inserting the catheter 30 into the living body, the burden on the patient increases, which hinders minimally invasive procedures.

[0044] From the above viewpoints, the inner diameter of the expansion part 32 can be, for example, 9 to 11 mm, and the inner diameter of the shaft part 33 can be, for example, 4 to 8 mm. Also, the wall thicknesses of the expansion part 32, the shaft part 33, and the intermediate part 34 can be, for example, 0.4 to 0.5 mm.

[0045] Also, as shown in FIG. 2, it is preferable that the tip part of the expansion part 32 forms a tapered part that gradually becomes thinner from the center of the expansion part 32 toward the outside in the axial direction. Thereby, the inner diameter of the tip of the expansion part 32 is continuous with the inner diameter of the tip chip 41 disposed on the tip side.

[0046] Hereinafter, the configurations of the expansion part 32, the shaft part 33, and the intermediate part 34 will be described in more detail.

[0047] As shown in FIG. 5(A), the expansion part 32 has a first reinforcing body 321 composed of wires W braided to cross each other, and a first resin layer 322 provided so as to cover the first reinforcing body 321.

[0048] As shown in FIG. 5(B), the shaft part 33 has a second reinforcing body 331 composed of wires W braided to cross each other, and a second resin layer 332 provided so as to cover the second reinforcing body 331.

[0049] As shown in FIG. 5(C), the middle portion 34 includes a third reinforcing member 341 formed by wires W woven so as to intersect, and a third resin layer 342 provided so as to cover the third reinforcing member 341.

[0050] As shown in FIG. 5(A), the first reinforcing member 321 is configured by weaving wires W at a weaving angle θ1. Further, as shown in FIG. 5(B), the second reinforcing member 331 is configured by weaving wires W at a weaving angle θ2. Also, as shown in FIG. 5(C), the third reinforcing member 341 is configured by weaving wires W at a weaving angle θ3.

[0051] In this specification, the weaving angles θ1, θ2, and θ3 are defined as the inner angles in the axial direction among the angles formed by the intersecting wires W, as shown in FIGS. 5(A), 5(B), and 5(C).

[0052] The weaving angle θ1 of the first reinforcing member 321 is configured to be smaller than the weaving angle θ2 of the second reinforcing member 331, as shown in FIGS. 5(A) and 5(B). Therefore, the inclination angle of the wire W constituting the first reinforcing member 321 with respect to the axial direction becomes smaller compared to the case where the weaving angle of the first reinforcing member 321 is larger than the weaving angle of the second reinforcing member 331.

[0053] Here, as the expansion portion 32 extends in the axial direction, the wire W constituting the first reinforcing member 321 of the expansion portion 32 deforms such that the inclination angle with respect to the axial direction gradually decreases. And when the inclination angle of the wire W constituting the first reinforcing member 321 of the expansion portion 32 with respect to the axial direction becomes approximately zero, the axial elongation of the expansion portion 32 is restricted.

[0054] Therefore, by configuring the weaving angle θ1 of the first reinforcing member 321 to be smaller than the weaving angle θ2 of the second reinforcing member 331, the elongation distance along the axial direction of the expansion portion 32 when inserting the stylet 50 into the catheter 30 is shorter compared to the case where the weaving angle of the first reinforcing member 321 is larger than the weaving angle of the second reinforcing member 331.

[0055] The knitting angle θ1 of the first reinforcing body 321 is not particularly limited, but is 100 degrees to 120 degrees. Further, the knitting angle θ2 of the second reinforcing body 331 is not particularly limited, but is 130 degrees to 150 degrees. By making the knitting angle θ2 of the second reinforcing body 331 larger than the knitting angle θ1 of the first reinforcing body 321 in this way, the kink resistance of the second reinforcing body 331 can be improved. For this reason, in the femoral vein having a complex structure, the catheter 30 can be suitably inserted into the living body.

[0056] As shown in FIGS. 5(A) and 5(B), the first reinforcing body 321 of the expansion part 32 is configured to be knitted so as to be sparser than the second reinforcing body 331 of the shaft part 33. According to this configuration, the expansion part 32 can be made softer and the stretchability can be enhanced as compared with the shaft part 33.

[0057] As shown in FIGS. 5 and 6, the knitting angle θ3 of the third reinforcing body 341 is configured to be smaller than the knitting angle θ1 of the first reinforcing body 321 and the knitting angle θ2 of the second reinforcing body 331.

[0058] Specifically, as shown in FIG. 6, the third reinforcing body 341 has a first region 341A in which the knitting angle θ3 is configured to gradually decrease from the knitting angle θ1 of the first reinforcing body 321, and a second region 341B that is continuous from the first region 341A and is configured to gradually increase toward the knitting angle θ2 of the second reinforcing body 331. The knitting angle θ3 of the third reinforcing body 341 at the boundary B between the first region 341A and the second region 341B is 50 degrees to 70 degrees.

[0059] When the intermediate portion 34 extends in the axial direction, the wire W forming the third reinforcing body 341 of the intermediate portion 34 deforms such that the inclination angle with respect to the axial direction gradually decreases. Thus, since the braiding angle θ3 of the third reinforcing body 341 is configured to be smaller than the braiding angle θ1 of the first reinforcing body 321 and the braiding angle θ3 of the second reinforcing body 331, compared with the case where the braiding angle θ3 of the third reinforcing body 341 is greater than or equal to the braiding angle θ1 of the first reinforcing body 321 and the braiding angle θ2 of the second reinforcing body 331, the inclination angle of the wire W forming the third reinforcing body 341 with respect to the axial direction becomes smaller, and the elongation distance along the axial direction of the intermediate portion 34 associated with inserting the stylet 50 into the catheter 30 becomes shorter. By thus shortening the elongation distance along the axial direction of the intermediate portion 34 associated with inserting the stylet 50 into the catheter 30, shrinkage of the intermediate portion 34 radially inward is suppressed, and it is possible to suitably prevent the stylet 50 from being clamped.

[0060] FIG. 8 is a photograph showing a state when the stylet 50 is inserted into a catheter 900 according to a comparative example. FIG. 9 is a photograph showing a state when the stylet 50 is inserted into the catheter 30 according to the present embodiment. In the catheter 900 according to the comparative example shown in FIG. 8, the braiding angle θ3 is configured to be larger than the braiding angle θ1 of the first reinforcing body 321. As shown in FIG. 8, by inserting the stylet 50 into the catheter 900, the lumen in the intermediate portion 934 of the catheter 900 contracts radially inward more than the outer diameter of the stylet 50, and the stylet 50 is clamped.

[0061] In contrast, as shown in FIG. 9, according to the catheter 30 of the present embodiment, shrinkage of the intermediate portion 34 radially inward is suppressed, and it is possible to suitably prevent the stylet 50 from being clamped.

[0062] In this embodiment, the wire W is made of a shape memory material such as a known shape memory metal or shape memory resin. As the shape memory metal, for example, titanium-based (Ni-Ti, Ti-Pd, Ti-Nb-Sn, etc.) or copper-based alloys can be used. As the shape memory resin, for example, acrylic resin, trans-isoprene polymer, polynorbornene, styrene-butadiene copolymer, and polyurethane can be used.

[0063] Since the wire W is made of a shape memory material, the contraction distance along the axial direction of the expansion part 32 accompanying the removal of the stylet 50 from the catheter 30 is the same as the elongation distance along the axial direction of the expansion part 32 accompanying the insertion of the stylet 50 into the catheter 30.

[0064] The wire diameter of the wire W is preferably 0.1 mm to 0.2 mm.

[0065] By setting the wire diameter of the wire W to 0.1 mm or more, the function as a reinforcing body for improving the strength can be suitably exhibited.

[0066] On the other hand, by setting the wire diameter of the wire W to 0.2 mm or less, the outer diameter of the expansion part 32 can be reduced while the inner diameter can be increased. Therefore, it is possible to achieve both suppression of the burden on the patient's body during catheter 30 insertion and reduction of pressure loss. Also, at this time, even at the location where the wire W is braided into two layers, it is possible to prevent the wire W from protruding from the first resin layer 322. In this embodiment, the cross-section of the wire W is circular, but it is not limited to this, and it may be rectangular, square, elliptical, etc.

[0067] The first resin layer 322 of the expansion part 32 is made of a soft material with a lower hardness than the second resin layer 332 of the shaft part 33. According to this configuration, the expansion part 32 can be made softer than the shaft part 33, and the stretchability can be enhanced.

[0068] As shown in FIG. 7, the third resin layer 342 of the middle portion 34 has a first region 342A formed of the first resin layer 322 of the expansion portion 32 and a second region 342B formed of the first resin layer 322 of the expansion portion 32 and the second resin layer 332 of the shaft portion 33. The length of the second region 342B along the axial direction is not particularly limited, but is, for example, 5 to 8 mm.

[0069] The first and second resin layers 322 and 332 can be formed using vinyl chloride, silicon, polyethylene, nylon, urethane, polyurethane, fluororesin, thermoplastic elastomer resin, etc., or using composite materials thereof.

[0070] The silicon material has high biocompatibility and is soft itself, so it has the feature of being difficult to damage blood vessels. The polyethylene material is soft and has a hardness that can withstand pressure. Moreover, the polyethylene material has biocompatibility comparable to that of the silicon material. The polyethylene material is harder than silicon and has the feature of being easy to insert into thin blood vessels. Also, the polyurethane material has the feature of becoming soft after insertion. As the materials for the first and second resin layers 322 and 332, materials that can utilize the features of these materials can be used.

[0071] Also, the polyurethane material may be subjected to a hydrophilic coating. In this case, the surface of the tube is smooth, making it easy to insert into blood vessels and difficult to damage the blood vessel wall. It is expected to prevent the adhesion of blood and proteins and the formation of thrombi.

[0072] The method for forming the catheter tube 31 is not particularly limited, and it can be formed, for example, by dip coating (immersion method) or insert molding. Note that the reinforcing bodies 321, 331, and 341 only need to have at least their outer surfaces covered by the resin layers 322, 332, and 342.

[0073] As shown in FIGS. 2 and 3, the tip chip 41 is disposed at the tip of the expansion portion 32. The tip chip 41 has a shape with a thin tip that gradually decreases in diameter toward the tip side.

[0074] Inside the tip chip 41, as shown in FIG. 3, a flat receiving surface 48 that abuts against the flat surface 50a of the stylet 50 used prior to the insertion of the catheter 30 into the living body is formed.

[0075] By fixing the hard tip chip 41 to the tip of the expansion part 32, it is possible to effectively prevent the expansion part 32 from collapsing during blood extraction.

[0076] Note that the configuration of the tip chip 41 is not limited to the above-described configuration.

[0077] As shown in FIGS. 2 to 4, the clamp tube 37 is provided on the proximal end side of the shaft portion 33. Inside the clamp tube 37, a lumen through which the stylet 50 can be inserted is provided. The clamp tube 37 can be formed using the same material as the catheter tube 31.

[0078] As shown in FIGS. 2 and 4, the catheter connector 35 connects the shaft portion 33 and the clamp tube 37. Inside the catheter connector 35, a lumen through which the stylet 50 can be inserted is provided.

[0079] As shown in FIGS. 2 to 4, the lock connector 36 is connected to the proximal end side of the clamp tube 37. Inside the lock connector 36, a lumen through which the stylet 50 can be inserted is provided. On the outer surface of the proximal end side of the lock connector 36, a male screw portion 36A provided with a thread is provided.

[0080] Next, the configuration of the stylet 50 will be described.

[0081] As shown in FIG. 2, the stylet 50 includes a stylet tube 51 that extends in the axial direction, a stylet hub 52 to which the proximal end of the stylet tube 51 is fixed, and a screw ring 53 provided at the tip of the stylet hub 52.

[0082] The stylet tube 51 is an elongated body that extends axially and is relatively rigid. The overall length of the stylet tube 51 along the axial direction is configured to be longer than the overall length of the catheter 30 along the axial direction. The stylet tube 51 is provided with a guide wire lumen 54 through which a guide wire (not shown) can be inserted. The stylet tube 51 is guided by the guide wire and inserted into the living body together with the catheter 30. After the catheter 30 is left in the living body, the stylet tube 51 is removed from the catheter 30 by pulling out the stylet hub 52 toward the proximal end side.

[0083] As shown in FIG. 2, the tip of the stylet tube 51 is provided with a flat surface 50a against which the receiving surface 48 of the tip chip 41 abuts. The stylet tube 51 is relatively rigid and has a stiffness that enables the pushing force applied to the tip side by the operation at the hand to be transmitted to the tip chip 41. For this reason, the stylet tube 51 plays a role of expanding a narrow blood vessel by bringing its flat surface 50a into contact with the receiving surface 48 of the tip chip 41 and pushing the tip chip 41 toward the tip side.

[0084] The twisting ring 53 has a female screw portion (not shown) with a screw groove provided on the inner surface of the lumen. By screwing the female screw portion of the twisting ring 53 onto the male screw portion 36A of the lock connector 36, the stylet 50 can be attached to the catheter 30.

[0085] <Method of using the catheter> Next, the method of using the above-described catheter 30 will be described. FIG. 2 shows a state before the stylet tube 51 of the stylet 50 is inserted into the lumen 30A of the catheter 30, and FIG. 4 shows a state after the stylet tube 51 is inserted into the lumen 30A of the catheter 30.

[0086] First, as shown in FIG. 4, the stylet tube 51 of the stylet 50 is inserted into the lumen 30A of the catheter 30. The stylet tube 51 passes through the inside of the shaft portion 33 and the expansion portion 32 in order, and the flat surface 50a of the stylet tube 51 abuts against the receiving surface 48 of the tip chip 41.

[0087] Here, as shown in FIG. 2, the total axial length of the stylet tube 51 is configured to be longer than the total axial length of the catheter 30. For this reason, with the flat surface 50a of the stylet tube 51 abutting against the receiving surface 48 of the tip chip 41, the tip chip 41 is pressed toward the tip side. As a result, the tip of the expansion portion 32 fixed to the tip chip 41 is pulled toward the tip side. Thereby, the catheter 30 receives a force to extend in the axial direction, and the relatively stretchable expansion portion 32 and the intermediate portion 34 of the catheter 30 extend in the axial direction. Thereafter, the proximal end of the catheter 30 is fixed to the stylet hub 52.

[0088] The expansion portion 32 extends in the axial direction, and the outer diameter of the expansion portion 32 becomes smaller and substantially the same as the outer diameter of the shaft portion 33 (see FIG. 4). The wire W constituting the first reinforcing body 321 of the expansion portion 32 is deformed so that the inclination angle with respect to the axial direction gradually decreases as the expansion portion 32 extends in the axial direction. Further, the wire W constituting the third reinforcing body 341 of the intermediate portion 34 is deformed so that the inclination angle with respect to the axial direction gradually decreases as the intermediate portion 34 extends in the axial direction.

[0089] As described above, since the braiding angle θ3 of the third reinforcing member 341 of the catheter 30 according to the present embodiment is configured to be smaller than the braiding angle θ1 of the first reinforcing member 321 and the braiding angle θ3 of the second reinforcing member 331, compared with the case where the braiding angle θ3 of the third reinforcing member 341 is larger than the braiding angle θ1 of the first reinforcing member 321 and the braiding angle θ2 of the second reinforcing member 331, the inclination angle of the wire W constituting the third reinforcing member 341 with respect to the axial direction becomes smaller, and the extension distance along the axial direction of the intermediate portion 34 when the stylet 50 is inserted into the catheter 30 becomes shorter. By shortening the extension distance along the axial direction of the intermediate portion 34 as the stylet 50 is inserted into the catheter 30 in this way, the contraction of the intermediate portion 34 inward in the radial direction is suppressed, and it is possible to suitably prevent the stylet 50 from being tightened.

[0090] Next, the catheter 30 with the stylet 50 inserted is inserted along a guide wire (not shown) that has been previously inserted into a target site in the living body. At this time, since the stylet 50 is inserted into the catheter 30, the outer diameters of the expansion portion 32 and the intermediate portion 34 are substantially the same as the outer diameter of the shaft portion 33, and the catheter 30 can be inserted into the living body with less invasion, and the burden on the patient's body can be suppressed.

[0091] Also, the catheter 30 is inserted into and left in the living body until the through holes 46 and 47 of the tip chip 41 are placed in the right atrium and the side hole 63 is placed in the inferior vena cava. With the through holes 46 and 47 and the side hole 63 arranged in the blood extraction target, the expansion portion 32 is arranged in the inferior vena cava, which is a relatively thick blood vessel, and the shaft portion 33 is arranged in the femoral vein, which is a relatively thin blood vessel.

[0092] Next, the stylet tube 51 and the guide wire are removed from the catheter 30. At this time, the stylet tube 51 and the guide wire are first withdrawn to the position of the clamp tube 37 of the catheter 30 and clamped by forceps (not shown), and then completely removed from the catheter 30. When the stylet tube 51 is removed from the lumen of the catheter 30, the catheter 30 is released from the axially extending force received from the stylet 50. Therefore, the expansion portion 32 contracts axially, and the inner diameter of the expansion portion 32 increases. Thereby, it is possible to reduce the pressure loss in the expansion portion 32 and ensure the flow rate of the liquid required.

[0093] Next, the lock connector 36 of the catheter 30 is connected to the blood withdrawal tube 11 of the extracorporeal circulation device shown in FIG. 1. After confirming that the connection of the catheter on the blood delivery side is completed, the forceps of the clamp tube 37 are released to start extracorporeal circulation.

[0094] When the extracorporeal circulation is completed, the catheter 30 is removed from the blood vessel, and hemostasis repair is performed by surgical techniques as necessary at the insertion site.

[0095] As described above, the catheter 30 according to the present embodiment is a catheter 30 that extends in the axial direction and allows blood to pass therethrough. The catheter 30 includes an expandable expansion portion 32 that extends in the axial direction, a shaft portion 33 that extends in the axial direction and is provided on the proximal end side in the insertion direction of the expansion portion 32, and an intermediate portion 34 that is provided between the expansion portion 32 and the shaft portion 33. The expansion portion 32 has an inner and outer diameter larger than that of the shaft portion 33 and is configured to be more stretchable than the shaft portion 33. The intermediate portion 34 is configured such that the inner and outer diameters gradually decrease from the expansion portion 32 toward the shaft portion 33. The expansion portion 32 has a first reinforcing body 321 formed of wires W braided so as to cross each other, the shaft portion 33 has a second reinforcing body 331 formed of wires W braided so as to cross each other, and the intermediate portion 34 has a third reinforcing body 341 formed of wires W braided so as to cross each other. The third reinforcing body 341 is configured such that a knitting angle θ3, which is an inner angle in the axial direction among the angles formed by the intersecting wires W, is smaller than those of the first reinforcing body 321 and the second reinforcing body 331.

[0096] According to the catheter 30 configured as described above, the catheter 30 can be inserted into the living body with the expansion portion 32 extended in the axial direction and the outer diameter reduced, thereby suppressing the burden on the patient's body. Further, after the catheter 30 is left in the living body, when the stylet 50 is removed from the catheter 30, the expansion portion 32 contracts in the axial direction and returns to its original state. Here, since the expansion portion 32 has an inner diameter larger than that of the shaft portion 33, the pressure loss in the expansion portion 32 is reduced, and the required liquid flow rate can be ensured.

[0097] Further, when the extension part 32 and the intermediate part 34 extend in the axial direction, the wire W forming the first reinforcing body 321 of the extension part 32 and the third reinforcing body 341 of the intermediate part 34 is deformed such that the inclination angle with respect to the axial direction gradually decreases. Here, since the knitting angle θ3, which is the inner angle in the axial direction among the angles formed by the intersecting wires W of the third reinforcing body 341, is configured to be smaller than those of the first reinforcing body 321 and the second reinforcing body 331, compared with the case where the knitting angle of the third reinforcing body is larger than those of the first reinforcing body and the second reinforcing body, the inclination angle of the wire W forming the third reinforcing body with respect to the axial direction becomes smaller, and the extension distance along the axial direction of the intermediate part 34 associated with inserting the stylet 50 into the catheter 30 becomes shorter. By thus shortening the extension distance along the axial direction of the intermediate part 34 associated with inserting the stylet 50 into the catheter 30, the inward contraction in the radial direction of the intermediate part 34 is suppressed, and it is possible to preferably prevent the stylet 50 from being clamped.

[0098] Therefore, it is possible to provide a catheter 30 that can reduce the pressure loss of the liquid circulating in the circulation circuit and ensure the flow rate of the liquid required without significantly increasing the invasion and burden on the patient's body, and can preferably prevent the stylet 50 from being clamped when the stylet 50 is inserted.

[0099] Further, the third reinforcing body 341 has a first region 341A in which the knitting angle θ3 is configured to gradually decrease from the knitting angle θ1 of the first reinforcing body 321, and a second region 341B that is continuous from the first region 341A and in which the knitting angle θ3 is configured to gradually increase toward the knitting angle θ2 of the second reinforcing body 331. According to the catheter 30 configured in this way, the length along the axial direction of the intermediate part 34 can be shortened, and it can also be preferably applied to a catheter 30 having a relatively short length along the axial direction.

[0100] <Second Embodiment> With reference to FIGS. 10 to 12, a percutaneous catheter (hereinafter referred to as "catheter") 60 according to the second embodiment of the present invention will be described. FIGS. 10 to 12 are diagrams for explaining the configuration of the catheter 60 according to the second embodiment.

[0101] This catheter 60 is a so-called double-lumen catheter that can perform both blood delivery and blood drainage simultaneously. Therefore, in this embodiment, in the extracorporeal circulation device of FIG. 1, instead of using two catheters, i.e., the venous-side catheter (blood drainage catheter) 5 and the arterial-side catheter (blood delivery catheter) 6, the procedure is performed using only one catheter 60.

[0102] The catheter 60 according to the second embodiment is different from the catheter 30 according to the first embodiment in that, as shown in FIGS. 10 and 11, a third tube 161 having a double-tube structure with a first lumen 61 communicating with the blood delivery side holes 163 is disposed in the lumen of the shaft portion 133.

[0103] According to the catheter 60 of the second embodiment, after operating the pump of the extracorporeal circulation device to drain blood from the vein (vena cava) of the patient, performing gas exchange in the blood by the artificial lung to oxygenate the blood, the blood can be returned to the vein (vena cava) of the patient again to perform veno-venous (VV) artificial lung extracorporeal blood circulation.

[0104] Hereinafter, each component of the catheter 60 will be described. Note that the parts common to the first embodiment will be omitted from the description, and only the parts characteristic of the second embodiment will be described. Also, the same reference numerals will be given to the same parts as those in the first embodiment described above for the description, and the overlapping descriptions will be omitted.

[0105] As shown in FIGS. 10 to 12, the catheter 60 has an expansion portion 32, a shaft portion 133, an intermediate portion 34, a tip chip 41 disposed at the tip of the expansion portion 32, and a third tube 161 disposed in the lumen of the shaft portion 133. Since the configurations of the expansion portion 32, the intermediate portion 34, and the tip chip 41 are the same as those of the catheter 30 of the first embodiment, the description thereof will be omitted.

[0106] As shown in FIG. 11, the catheter 60 has a first lumen 61 that functions as a blood feed channel, and a second lumen 62 that functions as a blood removal channel.

[0107] The first lumen 61 is formed in the inner cavity of the third tube 161. The second lumen 62 is formed in the inner cavities of the expansion section 32, the intermediate section 34, and the shaft section 133, and penetrates them from the distal end to the proximal end.

[0108] The shaft portion 133 is provided with a blood feed side hole 163 that communicates with the first lumen 61, which is a blood feed path.

[0109] The shaft portion 133 is provided with a blood removal side hole 164 that communicates with the second lumen 62 which is the blood removal path.

[0110] The blood feed side hole 163 and the blood removal side hole 164 are configured in an elliptical shape.

[0111] The third tube 161 is inserted into the second lumen 62 from the base end side of the shaft portion 133 and is connected to the blood feed side hole 163 .

[0112] The blood feed side hole 163 is disposed at a blood feed target inside a living body, and blood that has been oxygenated by the artificial lung is fed into the living body via the blood feed side hole 163.

[0113] The through-holes 46, 47 of the distal tip 41 and the blood removal side hole 164 of the shaft portion 133 are configured to be positioned at different blood removal targets within a living body to enable efficient blood removal. Even if the through-holes 46, 47 or the blood removal side hole 164 are adsorbed to the blood vessel wall and blocked, blood removal can be performed from the unblocked hole, allowing stable extracorporeal circulation.

[0114] In this embodiment, the catheter 60 is inserted from the internal jugular vein in the neck, passes through the superior vena cava and the right atrium, and the tip is placed in the inferior vena cava. The target for blood supply is the right atrium, and the targets for blood removal are two locations, the superior vena cava and the inferior vena cava.

[0115] As shown in Fig. 12, the catheter 60 is inserted and left in the living body such that with the stylet 50 inserted, the through holes 46 and 47 of the tip chip 41 face the inferior vena cava and the blood extraction side hole 164 of the shaft portion 133 faces the internal jugular vein.

[0116] Similar to the first embodiment, the expansion portion 32 is configured to have a larger inner diameter than the shaft portion 133. With the through holes 46 and 47 and the blood extraction side hole 164 arranged in the blood extraction target, the expansion portion 32 is arranged in the inferior vena cava, which is a relatively thick blood vessel, and the shaft portion 133 is arranged in the femoral vein, which is a relatively thin blood vessel.

[0117] As shown in Fig. 11, the lock connector 136 has a first lock connector 137 communicating with the first lumen 61 and a second lock connector 138 provided in parallel with the first lock connector 137 and communicating with the second lumen 62. The lock connector 136 is a Y-shaped Y connector in which the first lock connector 137 branches from the second lock connector 138.

[0118] The first lock connector 137 is connected to the proximal end portion of the third tube 161. The second lock connector 138 is coaxially connected to the proximal end portion of the shaft portion 133. A blood delivery tube (blood delivery line) is connected to the first lock connector 137, and a blood extraction tube (blood extraction line) is connected to the second lock connector 138.

[0119] The intermediate portion 34 exhibits the same function as that of the first embodiment, and the operational effects are also common.

[0120] As described above, according to the catheter 60 according to the present embodiment, both the functions of blood extraction and blood delivery can be achieved with one catheter.

[0121] Although the catheter according to the present invention has been described through the embodiments above, the present invention is not limited to only the configurations described in the embodiments and modification examples, and can be appropriately changed based on the description of the claims.

[0122] For example, in the above-described first embodiment, as shown in FIG. 6, the third reinforcing member 341 has a first region 341A in which the knitting angle θ3 is configured to gradually decrease from the knitting angle θ1 of the first reinforcing member 321, and a second region 341B that is continuous from the first region 341A and in which the knitting angle θ3 is configured to gradually increase toward the knitting angle θ2 of the second reinforcing member 331. However, as shown in FIG. 13, the third reinforcing member 341 may have a constant region 341C in which the knitting angle θ3 is constant between the first region 341A and the second region 341B. According to the catheter 30 configured in this way, the length along the axial direction of the intermediate portion 34 can be increased, and it can be suitably applied to a catheter having a relatively long length along the axial direction.

[0123] The material constituting the wire W is not limited to a configuration using a shape memory material as long as it has a restoring force to deform and return to its original shape and a function of reinforcing the resin layer, and for example, it can be constituted by a known elastic material.

[0124] Also, in the above-described second embodiment, the through holes 46 and 47 and the blood extraction side holes 164 are used for blood extraction, and the blood supply side holes 163 are used for blood supply. However, the through holes 46 and 47 and the side holes 164 may be used for blood supply, and the side holes 163 may be used for blood extraction.

[0125] Also, in the above-described first and second embodiments, the expansion part 32 is provided with the first resin layer 322, but the configuration is not limited to this, and it may be a configuration without the first resin layer.

[0126] This application is based on Japanese Patent Application No. 2020-029665 filed on February 25, 2020, the disclosure of which is incorporated herein by reference in its entirety.

Description of Reference Numerals

[0127] 30, 60 Catheter (Percutaneous Catheter), 32 Expansion Part, 321 First Reinforcing Member, 33, 133 Shaft part, 331 Second reinforcing body, 34 Intermediate part, 341 Third reinforcing body, θ1 Knitting angle of the first reinforcing body, θ2 Knitting angle of the second reinforcing body, θ3 Knitting angle of the third reinforcing body, W Wire.

Claims

1. 1. A percutaneous catheter for passing blood therethrough, the percutaneous catheter extending axially therethrough, the axially extending and expandable extension portion; a shaft portion extending in the axial direction and provided on a base end side in the insertion direction of the expansion portion; an intermediate portion disposed between the extension portion and the shaft portion; the extension portion has an inner and outer diameter larger than the shaft portion and includes a first reinforcement body, the first reinforcement body being made of cross-braided wires; the shaft portion has a second reinforcement body, the second reinforcement body being made of cross-braided wires; the intermediate section is configured such that an inner and outer diameter gradually decreases from the expansion section toward the shaft section, and the intermediate section has a third reinforcement body, the third reinforcement body being made of cross-braided wires; The braid angle of the first reinforcement body, which is an interior angle in the axial direction among the angles formed by the crossing wires, is smaller than that of the second reinforcement body, A percutaneous catheter, wherein the braid angle of the third reinforcement body is smaller than the braid angle of the second reinforcement body.

2. A percutaneous catheter extending axially and for passing blood, comprising: the axially extending and expandable extension portion; a shaft portion extending in the axial direction and provided on a base end side in the insertion direction of the expansion portion; an intermediate portion disposed between the extension portion and the shaft portion; the extension portion has an inner and outer diameter larger than the shaft portion and includes a first reinforcement body, the first reinforcement body being made of cross-braided wires; the shaft portion has a second reinforcement body, the second reinforcement body being made of cross-braided wires; the intermediate section is configured such that an inner and outer diameter gradually decreases from the expansion section toward the shaft section, and the intermediate section has a third reinforcement body, the third reinforcement body being made of cross-braided wires; The braid angle of the first reinforcement body, which is an interior angle in the axial direction among the angles formed by the crossing wires, is smaller than that of the second reinforcement body, A percutaneous catheter, wherein the braid angle of the third reinforcement body is smaller than the braid angle of the first reinforcement body.

3. The third reinforcing body is A first region in which the braid angle is configured to gradually decrease from the braid angle of the first reinforcement body; The percutaneous catheter according to claim 1 or 2, further comprising: a second region continuous from the first region, the braid angle of which is configured to gradually increase toward the braid angle of the second reinforcing body.

4. The percutaneous catheter according to claim 1 or 2, wherein the third reinforcement body has a constant region in which the braiding angle is constant.

5. The braid angle of the first reinforcement body is between 100 degrees and 120 degrees, The braid angle of the second reinforcement body is between 130 degrees and 150 degrees, The percutaneous catheter according to any one of claims 1 to 4, wherein the braiding angle of the third reinforcing body is 60 degrees or more.

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