JP2023032536A - Sheath and medical assembly - Google Patents

Abstract

To provide a sheath that can regulate radial shrinkage of a shaft part when a stylet is inserted, and is easily removed from the inside of a catheter.SOLUTION: A sheath 40 comprises: a main body part 41 extending in an axial direction; an insertion lumen 41L which is formed inside the main body part, and into which a stylet 50 is inserted; and a regulating part 43 for regulating radial shrinkage of a shaft part 33 while being inserted into the catheter.SELECTED DRAWING: Figure 7

Description

The present invention relates to sheaths and medical assemblies.

Conventionally, percutaneous cardiopulmonary support (PCPS) has been used for cardiopulmonary resuscitation, circulatory assistance, and respiratory assistance in emergency treatment. This percutaneous cardiopulmonary support method is a method of temporarily assisting/substituting for cardiopulmonary function using an extracorporeal circulation device.

The extracorporeal circulation apparatus includes an extracorporeal circulation circuit composed of a centrifugal pump, an oxygenator, a blood removal channel, a blood delivery channel, and the like, and performs gas exchange on the removed blood and sends the blood to the blood delivery channel.

When blood is circulated in this circulation circuit, the blood is circulated by the force of a pump driven by a motor. Therefore, it is required to reduce the pressure loss in the tubes that constitute the circulation circuit in order to circulate the blood appropriately.

However, if the inner diameter of the tube is small, the pressure loss increases and the flow rate through the circulation circuit decreases. Therefore, unless the inner diameter of the tube is sufficiently large, the required amount of blood circulation cannot be obtained.

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

In this regard, for example, Patent Document 1 below discloses a high performance cannula in which a cannula body (catheter) can be axially expanded or contracted by a mandrel (stylet) to expand or contract the diameter. disclosed. According to the high-performance cannula constructed in this manner, the cannula body is axially extended by the mandrel to reduce the diameter (outer diameter), and is inserted into the body of the patient, thereby minimizing invasiveness to the patient's body. become smaller in extent. Furthermore, by removing the mandrel after inserting the smart cannula into the body, the cannula body axially shrinks to increase its diameter (inner diameter). Therefore, the pressure loss in the catheter is reduced, and the required flow rate of the liquid can be ensured.

Patent No. 5059305

In the high-performance cannula disclosed in US Pat. No. 5,400,100, the distal end (extension) is axially extended and radially inwardly retracted when the stylet is inserted into the catheter. At this time, there is a possibility that the insertion point (shaft portion) located at the proximal end of the expanded portion may also expand in the axial direction and contract radially inward. When the shaft contracts radially inward in this way, the frictional resistance against the stylet increases, the stylet cannot be inserted to a desired position, and the expanded portion does not completely contract radially inward. If the expanded portion is not completely contracted radially inward and then inserted into the living body, the degree of invasiveness to the patient's body increases, which is not preferable.

On the other hand, if the stylet, etc., remains inserted into the catheter, the thickness of the tip of the stylet, etc. causes a step that causes blood to stagnate and generate shearing force, resulting in blood damage (thrombosis, hemolysis). may occur. Furthermore, if the stylet or the like remains inserted into the catheter, the lumen through which blood flows becomes smaller, resulting in pressure loss. Therefore, it is desired to easily remove the long member such as the stylet from the inside of the catheter after the catheter is placed at the desired position.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and is capable of restricting radial contraction of a shaft portion when a stylet is inserted and allowing the stylet to be easily removed from the interior of the catheter. The purpose is to provide a sheath.

A sheath that achieves the above object is a sheath configured to be attachable to and detachable from a catheter having an axially extending shaft portion and a lumen through which blood can flow. The sheath includes a main body portion extending in the axial direction, an insertion lumen formed inside the main body portion and into which the stylet is inserted, and a radial contraction of the shaft portion while being inserted into the catheter. and a regulation unit that regulates the

According to the sheath configured as described above, when the stylet is inserted into the catheter, the shaft portion attempts to contract radially inwardly, but the shaft portion contacts the restricting portion, causing the shaft portion to contract radially inwardly. Inward contraction is restricted. In this state, by moving the stylet distally, the distal end of the tube expands axially and preferably contracts radially inwardly. In addition, since the sheath is detachable from the catheter, it can be easily removed from the catheter. As described above, it is possible to provide a sheath that can restrict radial contraction of the shaft portion when the stylet is inserted, and that can be easily removed from the inside of the catheter.

1 is a system diagram showing an example of an extracorporeal circulation device to which a percutaneous catheter according to an embodiment of the present invention is applied; FIG. [ Fig. 2] Fig. 2 is a side view showing a state before the sheath and stylet according to the present embodiment are inserted into the catheter. Fig. 3 is a side cross-sectional view of a catheter; FIG. 4 is a schematic side view showing a state after the sheath and stylet according to the present embodiment are inserted through the catheter; FIG. 5(A) is a diagram for explaining the weaving angle of the first reinforcing body, and FIG. 5(B) is a diagram for explaining the weaving angle of the second reinforcing body. 1 is a schematic cross-sectional view showing the configuration of a sheath according to this embodiment; FIG. FIG. 4 is a diagram for explaining how to use the sheath and stylet according to the present embodiment; FIG. 4 is a plan view showing a state before the stylet according to the present embodiment is inserted through the double lumen catheter; Fig. 2 is a side cross-sectional view showing a double lumen catheter; FIG. 11 is a schematic side view showing a sheath according to a modification; FIG. 11 is a schematic side view showing a stylet according to a modification; FIG. 11 is a schematic side view showing a state after the sheath and stylet according to the modification are inserted through the catheter;

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 convenience of explanation, and may differ from the actual ratios.

FIG. 1 shows that a percutaneous catheter according to an embodiment of the present invention is applied to temporarily assist and replace the functions of the heart and lungs until the heart function recovers when the patient's heart is weakened. 1 is a system diagram showing an example of an extracorporeal circulation device used as percutaneous cardiopulmonary support (PCPS); FIG.

According to the extracorporeal circulation device 1, the pump is operated to remove blood from the patient's vein (caval vein), oxygenate the blood by performing gas exchange in the blood with an artificial lung, and then re-inject the blood. A Veno-Arterial (VA) procedure that returns to the patient's artery (aorta) can be performed. This extracorporeal circulation device 1 is a device that assists the heart and lungs. Hereinafter, a technique of removing blood from a patient, performing a predetermined treatment outside the body, and then reinjecting the blood into the patient's body is referred to as "extracorporeal circulation".

As shown in FIG. 1, the extracorporeal circulation device 1 has a circulation circuit for circulating blood. The circulation circuit includes an oxygenator 2, a centrifugal pump 3, a drive motor 4 which is driving means for driving the centrifugal pump 3, a venous catheter (percutaneous catheter for blood removal) 5, and an arterial catheter ( It has a blood feeding catheter) 6 and a controller 10 as a control unit.

A venous catheter (blood removal catheter) 5 is inserted from the femoral vein, and the tip of the venous catheter 5 is placed in the right atrium via the inferior vena cava. The venous catheter 5 is connected to the centrifugal pump 3 via a blood removal tube (blood removal line) 11 . The blood removal tube 11 is a conduit for sending blood.

An artery side catheter (blood feeding catheter) 6 is inserted from the femoral artery.

When the drive motor 4 operates the centrifugal pump 3 in accordance with the command SG from the controller 10, the centrifugal pump 3 removes blood from the blood removal tube 11 and passes the blood through the oxygenator 2, and then the blood supply tube (blood supply line). Blood can be returned to patient P via 12 .

Oxygenator 2 is arranged between centrifugal pump 3 and blood supply tube 12 . The oxygenator 2 performs gas exchange (oxygenation and/or carbon dioxide removal) for the blood. The oxygenator 2 is, for example, a membrane oxygenator, and preferably a hollow fiber membrane oxygenator. Oxygen gas is supplied from an oxygen gas supply unit 13 to the oxygenator 2 through a tube 14 . The blood supply tube 12 is a conduit connecting the oxygenator 2 and the arterial catheter 6 .

As the blood removal tube 11 and the blood transfer tube 12, for example, a highly transparent, elastically deformable flexible synthetic resin conduit such as vinyl chloride resin or silicone rubber can be used. Inside the blood removal tube 11, the liquid blood flows in the direction V1, and inside the blood supply tube 12, the blood flows in the direction V2.

In the circulation circuit shown in FIG. 1, an ultrasonic air bubble detection sensor 20 is arranged in the blood removal tube 11 . Fast clamp 17 is arranged in the middle of blood transfer tube 12 .

The ultrasonic air bubble detection sensor 20 detects air bubbles that have entered the circulation circuit due to an erroneous operation of the three-way stopcock 18, breakage of the tube, or the like during extracorporeal circulation. When the ultrasonic bubble detection sensor 20 detects that there are bubbles in the blood being sent into the blood removal 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 and lowers the rotational speed of the centrifugal pump 3 or stops the centrifugal pump 3 . Further, the controller 10 commands the fast clamp 17 to immediately occlude the blood transfer tube 12 with the fast clamp 17 . This prevents air bubbles from being sent into the patient's P body. The controller 10 controls the operation of the extracorporeal circulation device 1 to prevent air bubbles from entering the patient's P body.

The tube 11 (12, 19) of the circulation circuit of the extracorporeal circulation device 1 is provided with a pressure sensor. The pressure sensor is, for example, installed at any position A1 of the blood removal tube 11, A2 of the blood transfer tube 12 of the circulation circuit, or A3 of the connection tube 19 connecting between the centrifugal pump 3 and the oxygenator 2. or one or all of them. As a result, the pressure in the tube 11 (12, 19) can be measured by the pressure sensor while the extracorporeal circulation is performed on the patient P by the extracorporeal circulation device 1. FIG. The mounting positions of the pressure sensors are not limited to the mounting positions A1, A2, and A3, and can be mounted at arbitrary positions in the circulation circuit.

2 to 5, a percutaneous catheter (hereinafter referred to as "catheter") through which a sheath 40 and a stylet 50 (corresponding to a medical assembly) according to an embodiment of the present invention are inserted. 30 will be described. 2 to 5 are diagrams for explaining the configuration of the catheter 30. FIG. This catheter 30 is used as the venous side catheter (bleeding catheter) 5 in FIG. The configuration of the catheter 30 described below is an example, and the catheter through which the stylet 50 according to the present embodiment is inserted is not limited to the following configuration.

As shown in FIG. 2, the catheter 30 includes a tube 31 having a first side hole 63 and a second side hole 46, a distal tip 49 disposed at the distal end of the tube 31 and having a through hole 47, and a proximal end of the tube 31. It has a side-arranged clamping tube 34 , a catheter connector 35 connecting the tube 31 and the clamping tube 34 , and a lock connector 36 .

In this specification, the side to be inserted into the living body is called "distal end" or "distal end side", and the hand side operated by the operator is called "proximal end" or "proximal end side". The distal end means a fixed range including the distal end (most distal end) and its periphery, and the proximal end means a fixed range including the proximal end (most proximal end) and its periphery.

The catheter 30 has a lumen 30A penetrating from the distal end to the proximal end, as shown in FIG. The through hole 47 of the distal tip 49 and the first side hole 63 and the second side hole 46 of the tube 31 are configured to be arranged in different blood removal targets in the living body so that blood can be removed efficiently. ing.

When inserting the catheter 30 into the living body, the sheath 40 and the stylet 50 shown in FIG. 2 are used. The catheter 30, the sheath 40, and the stylet 50 are integrated in advance and inserted into the living body.

Each configuration of the catheter 30 will be described below. In addition, the configuration of the catheter 30 is not limited to the following.

The tube 31 has an extension portion 32 and a shaft portion 33 connected to the proximal end side of the extension portion 32, as shown in FIG.

The extension portion 32 is configured to have higher elasticity than the shaft portion 33 . Further, the extension portion 32 is configured to have an outer diameter and an inner diameter larger than those of the shaft portion 33 .

The extension part 32 and the shaft part 33 have lengths necessary for arranging the through hole 47 of the distal tip 49 and the first side hole 63 and the second side hole 46 of the tube 31 in the desired blood removal target. is configured to The length of the extension portion 32 can be, for example, 20-40 cm, and the length of the shaft portion 33 can be, for example, 20-30 cm.

In this embodiment, blood removal targets are the right atrium and the inferior vena cava. The catheter 30 is inserted into the body so that the through hole 47 of the distal tip 49 and the second side hole 46 of the tube 31 are positioned in the right atrium, and the first side hole 63 of the tube 31 is positioned in the inferior vena cava. detained.

With the through hole 47, the second side hole 46, and the first side hole 63 arranged in the target of blood removal, the extension part 32 is arranged in the inferior vena cava, which is a relatively large blood vessel, and the shaft part 33 is relatively large. It is placed in the femoral vein, which is a small blood vessel.

Further, when the stylet 50 is inserted through the lumen 30A of the catheter 30, the highly stretchable expansion portion 32 expands in the axial direction to reduce its outer diameter and inner diameter as shown in FIG. At this time, the outer diameter of the extended portion 32 is substantially the same as the outer diameter of the shaft portion 33 . Since the catheter 30 is inserted into the living body in a state in which the expansion portion 32 is axially extended to reduce the outer diameter and the inner diameter, the catheter 30 can be inserted in a minimally invasive manner.

Further, when the sheath 40 and the stylet 50 are removed from the lumen 30A of the catheter 30 after the catheter 30 is indwelled in the living body, the expanded portion 32 is contracted from the axially expanded state to increase the inner diameter (Fig. 7). (D)). Here, the extension 32 is placed in the inferior vena cava, which is a relatively large blood vessel. Therefore, the outer diameter of the expanded portion 32 can be increased, and the inner diameter can be increased accordingly.

Here, the pressure loss in the expanded portion 32 is equal to the total length of the expanded portion 32×(average) passage cross-sectional area. That is, by increasing the inner diameter of the expanded portion 32, the pressure loss in the expanded portion 32 is reduced. When the pressure loss in the expansion portion 32 is reduced, the flow rate of blood through the circulation circuit is increased. Therefore, in order to obtain a sufficient amount of blood circulation, it is necessary to increase the inner diameter of the expanded portion 32 .

On the other hand, when the wall thickness is substantially constant, increasing the inner diameters of the expansion portion 32 and the shaft portion 33 increases the outer diameter, which increases the burden on the patient when inserting the catheter 30 into the living body, and is minimally invasive. It interferes with proper technique.

From the above point of view, the inner diameter of the expansion portion 32 can be set to, for example, 9 to 11 mm, and the inner diameter of the shaft portion 33 can be set to, for example, 4 to 8 mm. Further, the thickness of the extension portion 32 and the shaft portion 33 can be set to 0.4 to 0.5 mm, for example.

Moreover, as shown in FIG. 2, the distal end of the extended portion 32 preferably forms a tapered portion that gradually tapers from the center of the extended portion 32 toward the distal end in the axial direction. As a result, the inner diameter of the distal end of the expanded portion 32 is continuous with the inner diameter of the distal tip 49 arranged on the distal side.

As shown in FIG. 5A, the extension part 32 includes a first reinforcing body 321 made of wires W braided so as to intersect, and a first resin layer provided to cover the first reinforcing body 321. 322 and .

As shown in FIG. 5B, the shaft portion 33 includes a second reinforcing body 331 made of wires W braided so as to intersect, and a second resin layer provided to cover the second reinforcing body 331. 332 and .

As shown in FIG. 5A, the first reinforcing body 321 is constructed by braiding the wire W at a braiding angle θ1. Moreover, as shown in FIG. 5(B), the second reinforcing body 331 is configured by braiding the wire W so as to have a braiding angle θ2.

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

The weaving angle θ1 of the first reinforcing member 321 is 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 wires W forming the first reinforcing body 321 with respect to the axial direction is smaller than when the weaving angle of the first reinforcing body 321 is larger than the weaving angle of the second reinforcing body 331 . The weaving angle θ1 of the first reinforcing member 321 may be set larger than the weaving angle θ2 of the second reinforcing member 331 .

Here, as the expansion portion 32 extends in the axial direction, the wire W forming the first reinforcing body 321 of the expansion portion 32 deforms such that the inclination angle with respect to the axial direction gradually decreases. When the angle of inclination of the wire W forming the first reinforcing member 321 of the extended portion 32 with respect to the axial direction becomes approximately zero, the extension of the extended portion 32 in the axial direction is restricted.

Therefore, by setting 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 weaving angle of the first reinforcing member 321 is larger than the weaving angle of the second reinforcing member 331. In comparison, the axial extension of extension 32 associated with passing stylet 50 through catheter 30 is reduced.

The weaving angle θ1 of the first reinforcing member 321 is not particularly limited, but is 100 to 120 degrees. Further, the weaving angle θ2 of the second reinforcing member 331 is not particularly limited, but is 130 degrees to 150 degrees. By making the weaving angle θ2 of the second reinforcing member 331 larger than the weaving angle θ1 of the first reinforcing member 321 in this manner, the kink resistance of the second reinforcing member 331 can be improved. Therefore, the catheter 30 can be preferably inserted into the living body through the femoral vein, which has a complicated structure.

As shown in FIGS. 5A and 5B, the first reinforcing member 321 of the extended portion 32 is braided so as to be looser than the second reinforcing member 331 of the shaft portion 33 . According to this configuration, the expansion portion 32 can be made softer than the shaft portion 33, and stretchability can be enhanced.

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.) and copper-based alloys can be used. Examples of shape memory resins that can be used include acrylic resins, trans-isoprene polymers, polynorbornenes, styrene-butadiene copolymers, and polyurethanes.

Since the wire W is made of a shape memory material, the axial contraction distance of the extension 32 as the stylet 50 is withdrawn from the catheter 30 is the same as the extension 32 as the stylet 50 is passed through the catheter 30. 32 axial extension distance.

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

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 preferably exhibited.

On the other hand, by setting the wire diameter of the wire W to 0.2 mm or less, it is possible to increase the inner diameter while reducing the outer diameter of the extension part 32, thereby suppressing the burden on the patient's body when inserting the catheter 30 and reducing the pressure. Both loss reduction can be achieved. In this embodiment, the wire W has a circular cross section, but is not limited to this, and may be rectangular, square, elliptical, or the like.

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

The first and second resin layers 322 and 332 can be formed using vinyl chloride, silicone, polyethylene, nylon, urethane, polyurethane, fluororesin, thermoplastic elastomer resin, or the like, or using a composite material thereof.

Silicone materials are highly biocompatible and soft, so they are less likely to damage blood vessels. The polyethylene material is soft and has hardness to withstand pressure. Moreover, polyethylene materials have biocompatibility comparable to silicon materials. Polyethylene material is harder than silicon and has the advantage of being easy to insert into small blood vessels. In addition, the polyurethane material has the advantage of becoming soft after insertion. As materials for the first and second resin layers 322 and 332, applicable materials can be used by taking advantage of the features of these materials.

Also, a hydrophilic coating may be applied to the polyurethane material. In this case, the surface of the tube is smooth, making it easy to insert into a blood vessel and not damaging the blood vessel wall. It is expected to prevent the formation of thrombus because it is difficult for blood and proteins to adhere to it.

Although the method of forming the extension part 32 and the shaft part 33 is not particularly limited, they can be formed by, for example, dip coating (immersion method) or insert molding. At least the outer surfaces of the reinforcing bodies 321 and 331 should be covered with the resin layers 322 and 332 .

The extension 32 has a second side hole 46, as shown in FIG. As shown in FIG. 2, a plurality of (four in FIG. 2) second side holes 46 are provided along the axial direction. It is preferable that a plurality of the second side holes 46 are provided also in the circumferential direction. The second side hole 46 functions as a blood removal hole.

The shaft portion 33 has a first side hole 63 as shown in FIG. The first side hole 63 functions as a blood removal hole. It is preferable to have a plurality of first side holes 63 in the circumferential direction. In this embodiment, the shaft portion 33 is provided with four first side holes 63 in the circumferential direction. As a result, even if one of the first side holes 63 adheres to the blood vessel wall and is blocked due to blood removal, blood can be removed by the other first side holes 63, thereby stabilizing blood circulation. It can be carried out.

Distal tip 49 is positioned at the distal end of extension 32, as shown in FIGS. The distal tip 49 has a tapered shape whose diameter gradually decreases toward the distal end.

Inside the distal tip 49, a flat receiving surface 48 is formed that abuts on the flat surface 50a of the stylet 50 used prior to inserting the catheter 30 into the living body.

The distal tip 49 is configured to accommodate the distal end of the wire W, as shown in FIG. The distal tip 49 has a through hole 47 . The through hole 47 functions as a blood removal hole. Through hole 47 of distal tip 49 constitutes a portion of lumen 30A of catheter 30 . The distal tip 49 can be made of urethane, for example.

By fixing the hard distal tip 49 to the distal end portion of the extended portion 32, it is possible to effectively prevent the extended portion 32 from being crushed during blood removal.

The clamp tube 34 is provided on the proximal end side of the shaft portion 33, as shown in FIGS. A lumen through which the stylet 50 can be inserted is provided inside the clamp tube 34 . The clamping tube 34 can be formed using the same material as the tube 31 .

The catheter connector 35 connects the shaft portion 33 and the clamping tube 34, as shown in FIGS. A lumen through which the stylet 50 can be inserted is provided inside the catheter connector 35 .

The lock connector 36 is connected to the proximal end of the clamping tube 34 as shown in FIGS. 2-4. A lumen through which the stylet 50 can be inserted is provided inside the lock connector 36 . An outer surface of the lock connector 36 on the proximal end side is provided with a male screw portion 36A provided with a screw thread. The male threaded portion 36A is fitted and held by the first holding portion 44 of the sheath 40, as shown in FIGS.

Next, the configuration of the sheath 40 according to this embodiment will be described with reference to FIG. 6 and the like. FIG. 6 is a diagram for explaining the configuration of the sheath 40 according to this embodiment.

The sheath 40 is detachably attached to the catheter 30 . As shown in FIG. 6 , the sheath 40 has a body portion 41 extending in the axial direction and a holding portion 42 provided on the proximal end side of the body portion 41 .

The outer periphery of the body portion 41 is configured as a restricting portion 43 that restricts contraction of the shaft portion 33 in the radial direction when the sheath 40 is inserted into the catheter 30 . The restriction portion 43 is configured by setting the hardness of the body portion 41 to be higher than the hardness of the shaft portion 33 .

An insertion lumen 41L into which the stylet 50 is inserted is formed on the inner periphery of the body portion 41 . As shown in FIG. 6, the distal end portion 41A of the body portion 41 is configured to be tapered. This configuration improves the insertability of the sheath 40 into the catheter 30 . Further, according to this configuration, when the extension portion 32 of the tube 31 is axially extended by the stylet 50 (see FIG. 7C), the extension portion 32 conforms to the shape of the distal end portion 41A of the main body portion 41. Since it deforms so as to follow, it is possible to prevent the occurrence of a step.

With the sheath 40 set on the catheter 30 (see FIG. 7A), the distal end portion 41A of the main body portion 41 is arranged inside the extension portion 32 . According to this configuration, it is possible to prevent the extension portion 32 from unintentionally hanging down during use in the state shown in FIG. 7(A).

Moreover, according to this configuration, the lumen surface of the catheter 30 is protected by the sheath 40, so that the lumen surface of the catheter 30 can be prevented from being damaged by the tip of the stylet 50 when the stylet 50 is inserted.

The material forming the body portion 41 is not particularly limited, but the same material as the first and second resin layers 322 and 332 described above can be used.

As shown in FIG. 6, the holding portion 42 is composed of one component, and includes a first holding portion 44 for holding the insertion state of the sheath 40 into the catheter 30, and a first holding portion 44 for holding the insertion state of the stylet 50 into the insertion lumen 41L. It has a second holding portion 45 for holding and a partition portion 42A interposed between the first holding portion 44 and the second holding portion 45 .

The first holding portion 44 is an elastic piece capable of pressing the male screw portion 36A of the catheter 30 radially inward. The second holding portion 45 is an elastic piece capable of pressing the stylet hub 52 of the stylet 50 radially inward. The holding force of the second holding portion 45 is greater than the holding force of the first holding portion 44 . According to this configuration, as shown in FIG. 7(D), by pulling out the stylet hub 52 toward the proximal end side, the sheath 40 and the stylet 50 can be removed while maintaining the connected state of the sheath 40 and the stylet 50. It can be withdrawn from the catheter 30 .

A partition wall 42 A is interposed between the first holding portion 44 and the second holding portion 45 . When the second holding portion 45 is held by the partition wall 42A, the first holding portion 44 is opened (that is, the holding of the catheter 30 is released) in order to prevent the holding force from being transmitted to the first holding portion 44. can be prevented.

In addition, the inner diameter of the second holding portion 45 increases toward the base end side in the axial direction. This makes it easier to insert the stylet hub 52 and makes it easier to grasp the stylet hub 52 together with the second holding portion 45 . Further, when the stylet 50 is removed from the second holding portion 45, the second holding portion 45 opens in the direction in which the expansion diameter of the second holding portion 45 expands, so the stylet 50 can be easily removed.

The holding portion 42 is made of rubber, for example, and has elasticity. Note that the holding portion 42 is not limited to rubber as long as it has a holding capability, and any material that allows the male screw portion 36A of the catheter 30 and the stylet hub 52 of the stylet 50 to be tightly fitted may be used.

Next, referring back to FIG. 2, the configuration of the stylet 50 according to this embodiment will be described.

As shown in FIG. 2, the stylet 50 has a stylet tube 51 extending in the axial direction and a stylet hub 52 to which the base end of the stylet tube 51 is fixed.

The stylet tube 51 is an elongated body extending in the axial direction and having relatively high rigidity. The total axial length of the stylet tube 51 is substantially the same as the axial length of the catheter 30 . The stylet tube 51 has a guidewire lumen 54 through which a guidewire (not shown) can be inserted. The stylet tube 51 is guided by a guide wire and inserted into the living body together with the sheath 40 and the catheter 30 . The stylet tube 51 is removed from the catheter 30 together with the sheath 40 by pulling out the stylet hub 52 to the proximal end side after the catheter 30 is left in the living body.

The stylet tube 51 has a relatively high rigidity, and is provided with a stiffness that enables transmission of pushing force toward the distal end side by operation at hand to the tube 31 . Therefore, the stylet tube 51 plays a role of dilating a narrow blood vessel by pushing it toward the distal end side while being fixed to the catheter 30 . Moreover, the hardness of the stylet tube 51 is preferably smaller than the hardness of the body portion 41 of the sheath 40 . According to this configuration, as shown in FIG. 7, the portion where the stylet tube 51 is exposed from the body portion 41 is made flexible, while the portion where the stylet tube 51 is arranged inside the body portion 41 is made rigid. can be done. Therefore, operability is improved.

The tip 52A of the stylet hub 52 has an outer diameter slightly larger than the inner diameter of the second holding portion 45 of the holding portion 42 . The stylet 50 can be held with respect to the sheath 40 by pushing the tip 52A of the stylet hub 52 into the second holding portion 45 .

<How to use the sheath and stylet>
Next, with reference to FIG. 7, a method of using the sheath 40 and stylet 50 described above will be described. FIG. 7 is a diagram for explaining how to use the sheath 40 and the stylet 50 according to this embodiment. 7, illustration of the wire W, the first side hole 63, the second side hole 46, and the like in the catheter 30 is omitted.

First, the sheath 40 is set on the catheter 30 as shown in FIG. 7(A). Specifically, the sheath 40 is inserted through the lumen 30A of the catheter 30 . At this time, the sheath 40 passes through the shaft portion 33 and the extension portion 32 in order. Then, the male screw portion 36A of the lock connector 36 of the catheter 30 is fitted and held in the first holding portion 44 of the holding portion 42 of the sheath 40 . At this time, since the distal end portion 41A of the main body portion 41 of the sheath 40 is positioned inside the expanded portion 32, it is possible to prevent the expanded portion 32 from unintentionally hanging down. reduce the risk of being

Next, as shown in FIG. 7B, the stylet 50 is inserted through the lumen 30A of the catheter 30 in which the sheath 40 is set. The stylet 50 sequentially passes through the interior of the shaft portion 33 and the extension portion 32 , and the flat surface 50 a of the stylet 50 contacts the receiving surface 48 of the distal tip 49 .

Here, as shown in FIG. 2, the total axial length of the stylet 50 is configured to be longer than the total axial length of the catheter 30 before the expansion portion 32 is expanded. Therefore, with the flat surface 50 a of the stylet 50 in contact with the receiving surface 48 of the distal tip 49 , the extended portion 32 is pressed distally.

Then, as shown in FIG. 7(C), the distal end of the extended portion 32 is pulled toward the distal end side. As a result, the catheter 30 receives an axially extending force, and the expanded portion 32 of the catheter 30, which has relatively high stretchability, is axially extended. In addition, although the shaft portion 33 tends to contract radially inward, the radially inward contraction of the shaft portion 33 can be prevented by the restricting portion 43 of the sheath 40 . In this state, by moving the stylet 50 distally, the extension 32 expands axially and preferably contracts radially inward.

Thereafter, as shown in FIG. 7(C), the stylet 50 is attached to the sheath 40 by fitting the stylet hub 52 of the stylet 50 to the second holding portion 45 of the holding portion 42 of the sheath 40 . and attached to the catheter 30 .

Next, the catheter 30 to which the sheath 40 and the stylet 50 are fixed is inserted along a guide wire (not shown) that has been inserted into the target site in vivo in advance. At this time, since the stylet 50 is inserted through the catheter 30, the outer diameter of the expanded portion 32 is substantially the same as the outer diameter of the shaft portion 33, so that the catheter 30 can be inserted into the living body in a minimally invasive manner. It is possible to suppress the burden on the patient's body.

Further, the catheter 30 is inserted into the living body until the through hole 47 of the distal tip 49 and the second side hole 46 of the tube 31 are arranged in the right atrium, and the first side hole 63 of the tube 31 is arranged in the inferior vena cava, detain. With the through hole 47, the first side hole 63, and the second side hole 46 arranged in the target for blood removal, the extended portion 32 is arranged in the inferior vena cava, which is a relatively large blood vessel, and the shaft portion 33 is relatively large. It is placed in the femoral vein, which is a small blood vessel.

The sheath 40 , stylet 50 and guidewire are then withdrawn from the catheter 30 . At this time, since the holding force of the second holding portion 45 is greater than the holding force of the first holding portion 44, as shown in FIG. The sheath 40 and stylet 50 can be removed from the catheter 30 while maintaining the connected state of 40 and stylet 50 .

The sheath 40, stylet 50, and guide wire are once pulled out to the clamping tube 34 of the catheter 30, clamped with forceps (not shown), and then completely pulled out of the catheter 30. FIG. Withdrawal of sheath 40 and stylet 50 from the lumen of catheter 30 relieves catheter 30 of the axially extending force that catheter 30 was subjected to from stylet 50 . Therefore, the expanded portion 32 contracts in the axial direction, and the inner diameter of the expanded portion 32 increases. As a result, the pressure loss in the expanded portion 32 can be reduced and the required flow rate of the liquid can be ensured.

Next, the lock connector 36 of the catheter 30 is connected to the blood removal tube 11 of the extracorporeal circulation system shown in FIG. After confirming that the connection of the catheter on the blood sending side is completed, the forceps of the clamp tube 34 are released to start extracorporeal circulation.

After the extracorporeal circulation is completed, the catheter 30 is removed from the blood vessel and the insertion site is surgically repaired to provide hemostasis if necessary.

As described above, the sheath 40 according to the present embodiment is detachable from the catheter 30 having the shaft portion 33 extending in the axial direction and the lumen 30A through which blood can flow. . The sheath 40 includes a main body portion 41 extending in the axial direction, an insertion lumen 41L formed inside the main body portion 41 and into which the stylet 50 is inserted, and a diameter of the shaft portion 33 in a state of being inserted into the catheter 30. and a restriction portion 43 that restricts contraction in the direction. According to the sheath 40 configured in this way, when the stylet 50 is inserted into the catheter 30 , the shaft portion 33 tries to contract radially inward, but the shaft portion 33 contacts the restricting portion 43 . , the radially inward contraction of the shaft portion 33 is restricted. In this state, by moving the stylet 50 to the distal side, the distal end of the tube 31 expands in the axial direction and preferably contracts radially inward. In addition, since the sheath 40 is detachable from the catheter 30 , it can be easily removed from the catheter 30 . As described above, when the stylet 50 is inserted, the radial contraction of the shaft portion 33 can be restricted, and the sheath 40 can be easily removed from the catheter 30 .

In addition, the sheath 40 according to the present embodiment includes a first holding portion 44 for holding the inserted state of the catheter 30, a second holding portion 45 for holding the inserted state of the stylet 50 into the insertion lumen 41L, have According to the sheath 40 configured in this way, the sheath 40 and the stylet 50 can be preferably fixed to the catheter 30, so that the sheath 40, the stylet 50 and the catheter 30 are inserted into the blood vessel. Improved operability.

The first holding portion 44 is an elastic piece capable of pressing the catheter 30 radially inward. According to this configuration, it is possible to maintain the inserted state of the sheath 40 with respect to the catheter 30 with a simple configuration.

The second holding portion 45 is an elastic piece capable of pressing the stylet 50 radially inward. According to this configuration, it is possible to maintain the insertion state of the stylet 50 into the insertion lumen 41L with a simple configuration.

Also, the holding force of the second holding portion 45 is greater than the holding force of the first holding portion 44 . According to this configuration, as shown in FIG. 7(D), by pulling out the stylet hub 52 toward the proximal end side, the sheath 40 and the stylet 50 can be removed while maintaining the connected state of the sheath 40 and the stylet 50. It can be withdrawn from the catheter 30 . Therefore, the operability during the procedure is improved.

Further, the restriction portion 43 is configured by making the body portion 41 harder than the shaft portion 33 . According to this configuration, the restricting portion 43 can be configured with a simple configuration.

Further, the distal end portion 41A of the body portion 41 is positioned inside the expanded portion 32 formed on the distal end side of the shaft portion 33 of the catheter 30 . The sheath 40 configured in this manner can prevent the extension 32 from unintentionally sagging, reducing the risk of contamination of the catheter tip.

<Modified example of catheter>
Next, modifications of the catheter will be described. In the embodiments described above, sheath 40 and stylet 50 were applied to catheter 30 with one lumen 30A. However, it can also be used with a double lumen catheter 60 as shown in FIGS. The configuration of a catheter 60 having a double lumen will be described below with reference to FIGS. 8 and 9. FIG.

The catheter 60 is a so-called double-lumen catheter, and is capable of both infusion and withdrawal of blood at the same time. Therefore, in this embodiment, in the extracorporeal circulation device of FIG. A procedure is performed using only the catheter 60 .

As shown in FIGS. 8 and 9, the catheter 60 has a double-tube structure in which a third tube 161 having a first lumen 61 communicating with a side hole 163 for blood transmission is arranged in the lumen of the shaft portion 133. have.

According to the catheter 60, the pump of the extracorporeal circulation device is operated to remove blood from the patient's vein (caval vein), oxygenate the blood by performing gas exchange in the blood with an artificial lung, and then oxygenate the blood. Veno-Venous (VV) oxygenated extracorporeal blood circulation can be performed by returning the blood to the patient's vein (caval vein).

As shown in FIGS. 8 and 9, the catheter 60 includes an extension portion 32, a shaft portion 133, a distal tip 49 arranged at the distal end of the extension portion 32, and a third tip 49 arranged in the lumen of the shaft portion 133. and a tube 161 . Since the configurations of the extended portion 32 and the distal tip 49 are the same as those of the catheter 30 of the first embodiment, description thereof will be omitted.

As shown in FIG. 9, the catheter 60 has a first lumen 61 functioning as a blood supply channel and a second lumen 62 functioning as a blood removal channel.

A first lumen 61 is formed in the lumen of the third tube 161 . A second lumen 62 is formed in the inner lumen of the extension portion 32 and the shaft portion 133 and penetrates from the distal end to the proximal end.

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

The shaft portion 133 has a blood removal side hole 164 that communicates with the second lumen 62, which is a blood removal path.

The blood supply side hole 163 and the blood removal side hole 164 are configured in an elliptical shape.

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

The blood supply side hole 163 is arranged in a blood supply target in the living body, and the blood oxygenated by the artificial lung is delivered into the living body through the blood supply side hole 163 .

The through hole 47 provided in the distal tip 49, the second side hole 46 provided in the extended portion 32, and the blood removal side hole 164 provided in the shaft portion 133 are arranged in different blood removal targets in vivo to efficiently remove blood. is configured to perform Further, even if the through hole 47, the second side hole 46, or the blood removal side hole 164 is blocked by adhesion to the blood vessel wall, blood can be removed from the hole that is not blocked. Extracorporeal circulation can be performed stably.

In this embodiment, the catheter 60 is inserted from the internal jugular vein in the neck, and the tip is left in the inferior vena cava via the superior vena cava and the right atrium. The target for blood supply is the right atrium, and the targets for blood removal are the superior vena cava and the inferior vena cava.

With the sheath 40 and the stylet 50 inserted into the catheter 60, the through hole 47 of the distal tip 49, the second side hole 46 of the expanded portion 32 are connected to the inferior vena cava, and the blood removal side hole 164 of the shaft portion 133 is connected. is placed in the internal jugular vein and left in the body.

The extension portion 32 is configured to have an inner diameter larger than that of the shaft portion 133 . With the through hole 47, the second side hole 46, and the blood removal side hole 164 arranged in the blood removal target, the extension part 32 is placed in the inferior vena cava, which is a relatively thick blood vessel, and the shaft part 133 is placed in the comparative It is placed in the femoral vein, which is a very small blood vessel.

As shown in FIG. 9 , the lock connector 136 includes a first lock connector 137 communicating with the first lumen 61 and a second lock connector 137 provided in parallel with the first lock connector 137 and communicating with the second lumen 62 . 138 and . The lock connector 136 is a Y-shaped Y connector formed by branching a first lock connector 137 from a second lock connector 138 .

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

As described above, according to the catheter 60 according to the present embodiment, a single catheter can perform both blood removal and blood feeding functions.

Although the catheter according to the present invention has been described above through the embodiments, the present invention is not limited to the configurations described in the embodiments and modifications, and can be appropriately modified based on the description of the claims. It is possible.

For example, in the above-described embodiment, the first holding portion 44 is an elastic piece capable of pressing the tube 31 radially inward. However, the first holding portion may be a female threaded portion that can be screwed onto the male threaded portion 36A of the lock connector 36 .

In addition, the material constituting the wire W is not limited to a shape memory material as long as it has a restoring force to deform and return to its original shape and has a function to reinforce the resin layer. It can be made of a known elastic material.

Further, in the above-described embodiment, the holding force of the second holding portion 45 is greater than the holding force of the first holding portion 44, but the holding force of the second holding portion 45 is equal to the holding force of the first holding portion 44. may be smaller than At this time, when removing the sheath 40 and the stylet 50 , the sheath 40 and the stylet 50 are removed while holding the stylet 50 by hand so that the stylet 50 does not come off from the second holding portion 45 .

Further, in the above-described embodiment, the configuration including the expanded portion 32 as the catheter 30 has been described as an example. However, the catheter may be configured without extensions.

10, the sheath 140 may have a holder 141, and the stylet 150 may have a hub 151, as shown in FIG. In this configuration, the sheath 140 is slidably inserted into the catheter 30 as shown in FIG. Then, as shown in FIG. 12, the sheath 140 is fixed to the proximal end portion of the catheter 30 by fixing the stylet 150 inserted from the proximal end side of the sheath 140 to the catheter 30 by, for example, screwing. be. By fitting the catheter 30 and the stylet 150 with the holder 141, the sheath 140 can be easily removed when the stylet 150 is removed.

30, 60 catheters (percutaneous catheters),
30A lumens,
31 catheter tube (tube),
32 extensions,
33, 133 shaft portion,
36A male screw part,
40, 140 sheath,
41 main body,
41A the tip of the main body,
41L insertion lumen,
43 Regulatory Department,
44 first holding portion,
45 second holding part,
50, 150 stylet.

Claims (8)

A sheath detachable from a catheter having a shaft portion extending in the axial direction and a lumen through which blood can flow,
an axially extending body;
an insertion lumen formed inside the main body and into which the stylet is inserted;
a restricting portion that restricts contraction of the shaft portion in a radial direction while being inserted into the catheter. a first holding part for holding an inserted state with respect to the catheter;
2. The sheath according to claim 1, further comprising a second holding portion for holding the inserted state of the stylet with respect to the insertion lumen. The sheath according to claim 2, wherein the first holding portion is an elastic piece or a female screw portion capable of pushing the catheter radially inward. The sheath according to claim 2 or 3, wherein the second holding portion is an elastic piece capable of pressing the stylet radially inward. The sheath according to any one of claims 2 to 4, wherein the holding force of the second holding portion is greater than the holding force of the first holding portion. The sheath according to any one of claims 1 to 5, wherein the regulating portion is configured such that the hardness of the body portion is higher than that of the shaft portion. The sheath according to any one of claims 1 to 6, wherein the distal end of the main body portion is positioned inside an expanded portion formed on the distal end side of the shaft portion of the catheter. A sheath according to any one of claims 1 to 7,
and said stylet inserted into said insertion lumen of said sheath.

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