Patent Application
20250135155
The present disclosure relates to an indwelling catheter indwelled in a living body lumen such as a blood vessel to administer a predetermined administered substance.
Conventionally, there has been known an indwelling catheter indwelled in a living body lumen such as a blood vessel for administering an administered substance such as various nutrients and medical agents to an administration target (refer to JP 11-33107 A). In a procedure using a peripherally inserted central venous catheter (PICC), which is a type of indwelling catheters, for example, the catheter is introduced into the blood vessel from a puncture site formed in a vein (for example, basilic vein, cephalic vein, median cubital vein and the like) located in the periphery of a body such as a hand, an arm, or an elbow, and a distal end of the catheter is indwelled in a central vein (for example, superior vena cava) via an axillary vein or a subclavian vein.
In an indwelling catheter indwelled in a blood vessel, a catheter distal end position at the time of indwelling is important to appropriately administer an administered substance to a target site. If the distal end position is displaced, there is a case in which the administration cannot be appropriately performed, for example, the administration is performed toward another blood vessel, and there is a possibility that a sufficient effect by the administered substance cannot be expected.
Since the indwelling catheter is a device indwelled in the blood vessel to be used, a distal end might be displaced from the initial indwelling position due to body movement of a patient, recoil when a medical agent is administered and the like. For example, in a case in which the medical agent is administered via the catheter, the distal end is drawn toward a proximal end side due to the recoil when the medical agent is administered. In such a case, with a catheter having a high restoring property of the catheter distal end (distal end returning property), the distal end moved toward the proximal end side returns to the initial indwelling position again; however, with a catheter having a low restoring property, after being drawn from the initial indwelling position to the proximal end side, the catheter cannot return to the initial indwelling position and the distal end position remains displaced.
The inventors of the present application have intensively studied the properties of the catheter to enhance the distal end returning property of the catheter against such unintended positional displacement of the catheter distal end. The inventors of the present application have found that a mutual relationship between slipperiness of a surface of the catheter and physical properties of the catheter (shape restoring property (shape restoring rate) of the distal end shape and hardness (initial elasticity) of the catheter) is significantly involved in the distal end returning property of the catheter, and have developed the present invention.
At least one embodiment of the present disclosure has been made in view of the above-described circumstances, and specifically, an object of certain embodiments is to provide an indwelling catheter having an excellent distal end returning property for returning a distal end position to an initial indwelling position even when positional displacement occurs on a catheter distal end in a state of being indwelled in a living body lumen.
An indwelling catheter according to one embodiment includes a shaft including a lumen, the indwelling catheter indwelled in a living body lumen, in which an outer diameter is 2.5 mm or less, initial elasticity in warm water at 37° C. is 0.012 N/mm to 0.13 N/mm, a shape restoring rate in warm water at 37° C. is 73% or more, and sliding resistance in physiological saline at 23° C. is 0.025 N or less.
An indwelling catheter according to at least one embodiment of the present invention is provided with three characteristic physical properties of initial elasticity, a shape restoring rate, and sliding resistance, so that even if the position of the distal end is displaced from the initial indwelling position due to the positional displacement mechanism at the time of indwelling in the blood vessel, appropriate elasticity and slipperiness necessary for returning to the initial indwelling position are provided. Therefore, even if the distal end position is displaced in a state in which the indwelling catheter is indwelled in the living body lumen, this can return the distal end position to the initial indwelling position by exhibiting an excellent distal end returning property.
Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Embodiments described herein are illustrated to embody the technical ideas of the present invention, but the present invention is not limited to the described embodiments. Other feasible embodiments, examples, operation technologies and the like that could be conceived by those skilled in the art without departing from the gist of the present invention are all included in the scope and gist of the present invention and included in the invention recited in claims and the scope of equivalents thereof.
Moreover, for convenience of illustration and ease of understanding, the drawings attached to the present specification might be schematically represented by changing a scale, an aspect ratio, a shape and the like from actual ones as appropriate. The drawings are merely examples, and do not limit the interpretation of the present invention.
In the description of the present specification, a side on which an indwelling catheter 1 is inserted into a blood vessel is referred to as a “distal end side,” and a side opposite to the distal end side (a side gripped by an operator) is referred to as a “proximal end side.” A portion including a certain range in a long axis direction from a distal end (most distal end) is referred to as a “distal end portion,” and a portion including a certain range in the long axis direction from a proximal end (most proximal end) is referred to as a “proximal end portion.”
The indwelling catheter 1 according to the present embodiment is a medical device used for administering a predetermined administered substance to an administration target over a long period of time in a state of being indwelled in a living body lumen such as the blood vessel. The indwelling catheter 1 can be formed as a central venous catheter (CVC) for intravenous indwelling such as a PICC, for example. The indwelling catheter 1 configured as the central venous catheter is percutaneously inserted into the living body lumen (for example, the basilic vein, cephalic vein, median cubital vein and the like) by a Seldinger method and the like, and a distal end thereof is delivered to a target indwelling position (for example, the superior vena cava and the like) to be indwelled.
As illustrated in
A shaft 10 serving as a main body of the indwelling catheter 1 includes the lumen 11. A hub 20 serving as a port for administering the administered substance is attached to a proximal end side of the shaft 10. The number of lumens 11 of the shaft 10 is not limited to one, and may be plural. The hub 20 may include a plurality of ports in accordance with the number of lumens 11.
The shaft 10 may be formed of a material having flexibility. The material forming the shaft 10 is not particularly limited, but a material satisfying at least physical properties (initial elasticity and shape restoring property) of the indwelling catheter 1 to be described later is appropriately selected. The shaft 10 can be formed of, for example, polyolefins such as polyethylene, polypropylene, an ethylene-propylene copolymer, and an ethylene-vinyl acetate copolymer, thermoplastic resins such as soft polyvinyl chloride, various elastomers such as a polyurethane resin, a polyamide resin, and a polyester resin, crystalline plastics such as polyamide, crystalline polyethylene, and crystalline polypropylene, a silicon resin and the like. As the polyurethane resin, that containing a diisocyanate, a diol chain extender, and a polyglycol as main components, in which the diisocyanate is an aromatic diisocyanate, the diol is an aliphatic diol, and the polyglycol is an aromatic polyglycol or an aliphatic polyglycol can be suitably used. The shaft 10 can also use a mixture containing two or more kinds of the above-described materials as a constituent material.
Note that these materials may contain an antithrombotic material having antithrombogenicity and biocompatibility (effect of suppressing and preventing adhesion/adhesion of platelets, and effect of suppressing and preventing activation of platelets). The antithrombotic material includes a physiologically active substance having antithrombogenicity, an antithrombotic synthetic polymer material having a chemical structure exhibiting antithrombogenicity and suppressing adsorption of proteins and the like. Examples of the physiologically active substance include heparin, prostaglandin, urokinase, and arginine derivative, for example. Examples of the antithrombotic synthetic polymer material include a polymer material including zwitterionic monomers exhibiting antithrombogenicity, such as, for example, 2-methoxyethyl acrylate (2-MEA) and a betaine-type monomer (sulfobetaine-type monomer, carboxybetaine-type monomer such as phosphobetaine-type monomer containing a phosphorylcholine group such as 2-methacryloyloxyethyl phosphorylcholine (MPC)), for example. These antithrombotic materials may be used alone or in a form of a mixture of two or more of them.
In a case in which the indwelling catheter 1 is a device intended for being indwelled in the blood vessel (mainly vein) as the living body lumen, an outer diameter of the shaft 10 is 2.5 mm or less, preferably 1.0 mm or more and 1.7 mm or less.
An outer surface of the shaft 10 is provided with a lubricative coating that functions as a friction reducing portion for reducing sliding resistance at the time of insertion into the blood vessel and improving a distal end returning property for unintended displacement of a distal end position.
The lubricative coating is not particularly limited as long as this swells upon contact with a body fluid or an aqueous solvent and expresses high lubricity in a living body, and a material satisfying at least the physical property (sliding resistance) of the indwelling catheter 1 to be described later is appropriately selected. The lubricative coating can be formed of, for example, a low-friction material such as a hydrophilic material. Examples of the hydrophilic material include hydrophilic polymers such as cellulose-based polymer substances, polyethylene oxide-based polymer substances, maleic anhydride-based polymer substances (for example, a maleic anhydride copolymer such as a methyl vinyl ether-maleic anhydride copolymer), acrylamide-based polymer substances (for example, a block copolymer of polyacrylamide and glycidyl methacrylate-dimethylacrylamide), water-soluble nylon, polyvinyl alcohol, polyvinyl pyrrolidone, and derivatives thereof, for example.
The lubricative coating may contain an antithrombotic material (physiologically active substances, antithrombotic synthetic polymer materials and the like) having antithrombogenicity and biocompatibility. Note that, as the antithrombotic material contained in the lubricative coating, the antithrombotic material similar to that applicable as the constituent material of the shaft 10 described above can be used. As a result, the shaft 10 of the indwelling catheter 1 has excellent slipperiness, and can exhibit excellent antithrombogenicity even when this is indwelled in the blood vessel for a long period of time.
The outer surface of the indwelling catheter 1 may be coated with the lubricative coating using known coating treatment (such as dip coating or spray coating). The indwelling catheter 1 may have a configuration in which a functional layer having a friction reducing function during shaft molding is provided on the outer surface in advance, in addition to a configuration in which the outer surface is coated with a low-friction material by the coating treatment.
The administered substance administered from the indwelling catheter 1 can be appropriately selected according to a therapeutic purpose. The administered substance is a fluid composition that can express a predetermined effect by being administered to the living body as the administration target, and can be intermittently released from the device. The administered substance is, for example, a medical agent (liquid agent) intended for treatment of predetermined disease and various nutrients. The medical agent includes a drug. The drug can be any physiologically or pharmacologically active substance, in particular one known to be delivered to a human or animal body. Examples of the medical agent include, but are not limited to, an infusion agent, an anticancer agent, an antibacterial agent and the like, for example.
The indwelling catheter 1 according to the present embodiment is provided with the following physical properties for improving the distal end returning property to solve a problem caused by positional displacement of the distal end that might occur during indwelling in the blood vessel as illustrated in
In the indwelling catheter 1, the outer diameter of the shaft 10 is set to 2.5 mm, “initial elasticity in warm water at 37° C. is set to 0.012 N/mm to 0.13 N/mm (first physical property),” “a shape restoring rate in warm water at 37° C. is set to 73% or more (second physical property),” and “sliding resistance in physiological saline at 23° C. is set to 0.025 N or less (third physical property).” Provided with these three characteristic physical properties, the indwelling catheter 1 is excellent in distal end returning property as compared with a known indwelling catheter, and can be returned to the initial indwelling position (or a position at which administration of the administered substance is not interfered) even if the positional displacement of the distal end occurs.
Hereinafter, the three physical properties (first to third physical properties) of the indwelling catheter 1 will be described in detail.
The initial elasticity is a physical property value [N/mm] quantitatively indicating hardness of the shaft 10 of the indwelling catheter 1. The initial elasticity of the indwelling catheter 1 is uniquely defined by a type and a composition ratio of constituent materials, and a product size (inner and outer diameters and the like).
The initial elasticity can be measured using a test device 100 illustrated in
As a measurement method using the test device 100, the indwelling catheter 1 is arranged on the supports 110, the pressing drive unit 130 is driven to move the indenter 120 so as to press the same by a predetermined pressing distance (for example, 0.1 mm) at a predetermined pressing speed (for example, 20 mm/min), and a pressing load [N] and the pressing distance [mm] are measured. The initial elasticity is a physical property value obtained on the basis of the pressing load [N] and the pressing distance [mm] when the indwelling catheter 1 is pressed by the indenter 120; the larger the value, the harder, and the smaller the value, the softer. The initial elasticity can also be said to be a proportional constant (inclination) at an initial stage of deformation between the pressing load and the pressing distance.
In the indwelling catheter 1 according to the present embodiment, in a case in which the distal end returning property for a positional displacement mechanism at the time of indwelling in the blood vessel is improved, the initial elasticity is preferably set in a range of 0.012 N/mm to 0.13 N/mm, and more preferably set in a range of 0.027 N/mm to 0.036 N/mm. By setting the initial elasticity of the indwelling catheter 1 within the above-described range, it is possible to exhibit an appropriate shape retaining property necessary for the distal end to return to the initial indwelling position when this is drawn toward the proximal end side, for example.
The shape restoring rate is a physical property value [%] quantitatively indicating a restoring property for the deformed shaft 10 of the indwelling catheter 1 to return to its original shape.
The shape restoring rate can be measured using a test device 200 illustrated in
As a measurement method using the test device 200, the indwelling catheter 1 is arranged on the placing surface 210, the indwelling catheter 1 is wound around the column 220 by 180° and the indwelling catheter 1 is separated after a predetermined time elapses (for example, after one second) to release a wound state, and an angle between an outer surface facing the placing surface 210 and the placing surface 210 in the distal end portion of the indwelling catheter 1 after the winding is released is measured. The shape restoring rate is a physical property value on the basis of the angle between the indwelling catheter 1 and the placing surface 210 serving as a reference surface before and after winding of the indwelling catheter 1, and can be obtained from following Expression 1 by measuring the angle of the indwelling catheter 1 after the winding is released. The shape restoring rate indicates that the larger the value, the higher the restoring property, and the smaller the value, the lower the restoring property. For example, when the angle of the indwelling catheter 1 after the winding is released is 0°, the shape restoring rate is “100%,” which means the restoration to the original shape.
Expression 1: Angle from placing surface 210 after winding is released/180°×100%.
In the indwelling catheter 1 according to the present embodiment, in a case in which the distal end returning property for the positional displacement mechanism at the time of indwelling in the blood vessel is improved, the shape restoring rate is preferably set to 73% or more, and more preferably set to 79% or more. By setting the shape restoring rate within the above-described range, the indwelling catheter 1 can exhibit an appropriate shape restoring property necessary for the distal end to return to the initial indwelling position when this is drawn toward the proximal end side, for example.
The sliding resistance is a physical property value [N] quantitatively indicating ease of sliding when the indwelling catheter 1 is inserted into the blood vessel. That is, the sliding resistance means magnitude of resistance when moving the shaft 10 in a bent state in the axial direction relative to the lumen of a unit length.
The sliding resistance can be measured using a test device 300 illustrated in
As a measurement method using the test device 300, a tensile load [N] when the indwelling catheter 1 is inserted into the blood vessel model 330 and the tensile drive unit 340 is driven is measured. The sliding resistance is a physical property value indicating magnitude of the frictional resistance when passing through the blood vessel model 330, indicating that the larger the value, the higher the frictional resistance, and the smaller the value, the lower the frictional resistance.
In the indwelling catheter 1 according to the present embodiment, in a case in which the distal end returning property for the positional displacement mechanism at the time of indwelling in the blood vessel is improved, the sliding resistance is preferably set to 0.025 N or less. By setting the sliding resistance of the indwelling catheter 1 within the above-described range, it is possible to exhibit appropriate slipperiness necessary for the distal end to return to the initial indwelling position when this is drawn toward the proximal end side, for example.
As described above, the indwelling catheter 1 is provided with the three characteristic physical properties (initial elasticity, shape restoring rate, and sliding resistance) measured using the test devices 100, 200, and 300. The indwelling catheter 1 is a device excellent in distal end returning property. Therefore, even in a case in which the positional displacement of the distal end occurs in the indwelling catheter 1 in a state of being indwelled in the blood vessel, this can return to the initial indwelling position by exhibiting the excellent distal end returning property.
The distal end returning property of the indwelling catheter 1 can be evaluated by a distal end returning rate [%] obtained by a test device 400 illustrated in
As illustrated in
As a measurement method using the test device 400, the table 410 on which the scale 420 is arranged is installed in the water tank X3 storing warm water. The indwelling catheter 1 is placed on the blood vessel 430 in parallel with the scale 420, and a distal end position is aligned to a scale of zero of the scale 420. To accurately measure the initial position B1 and the return position B3 when placing the indwelling catheter 1 on the blood vessel 430, a contact distance L (for example, 90 mm) between the blood vessel 430 and the shaft 10 in a state in which the indwelling catheter 1 is placed on the blood vessel 430 is defined in advance. To suppress the movement of the indwelling catheter 1 due to a water flow that might occur during the test, a height of a water surface of the warm water stored in the water tank X3 is set substantially equivalent to a height of an uppermost surface of the indwelling catheter 1. Next, after the distal end of the indwelling catheter 1 is drawn from the initial position B1 toward the proximal end side by a predetermined distance (for example, 25 mm) and moved to a drawn position B2, the drawing is released. A drawing/releasing operation the distal end position of the indwelling catheter 1 can be performed, for example, by pressing the proximal end side of the indwelling catheter 1 in a bottom direction of the water tank X3 with a finger of an examiner and the like and then releasing the pressing. In
The indwelling catheter 1 according to the present embodiment is provided with the three characteristic physical properties (initial elasticity, shape restoring rate, and sliding resistance), the distal end returning rate is 96% or more. Therefore, even in a case in which the positional displacement of the distal end occurs in the indwelling catheter 1 in a state of being indwelled in the blood vessel, this can return to the initial indwelling position (or a position at which administration of the administered substance is not interfered) by exhibiting the excellent distal end returning property.
As described above, the indwelling catheter according to the present embodiment is a catheter provided with the shaft 10 including the lumen 11 and is indwelled in the living body lumen, the catheter having the outer diameter of 2.5 mm or less, the initial elasticity in warm water at 37° C. of 0.012 N/mm to 0.13 N/mm, the shape restoring rate in warm water at 37° C. of 73% or more, and the sliding resistance in physiological saline at 23° C. of 0.025 N or less. The indwelling catheter 1 preferably has the initial elasticity of 0.027 N/mm to 0.036 N/mm, and the shape restoring rate of 79% or more.
The indwelling catheter 1 is provided with the three characteristic physical properties of the initial elasticity, the shape restoring rate, and the sliding resistance in the above-described range, so that even if the position of the distal end is displaced from the initial indwelling position due to the positional displacement mechanism at the time of indwelling in the blood vessel, this is provided with appropriate elasticity and slipperiness necessary for returning to the initial indwelling position. Therefore, even if the distal end position is displaced in a state in which the indwelling catheter 1 is indwelled in the living body lumen, this can return the distal end position to the initial indwelling position by exhibiting the excellent distal end returning property.
In the indwelling catheter 1 according to the present embodiment, it is preferable that the lubricative coating is applied to the outer surface of the shaft 10, and further, it is particularly preferable that the lubricative coating is a physiologically active substance having antithrombogenicity or a configuration having a chemical structure exhibiting antithrombogenicity (a configuration containing an antithrombotic material such as a physiologically active substance having antithrombogenicity and an antithrombotic synthetic polymer material having a chemical structure exhibiting antithrombogenicity and suppressing adsorption of proteins).
With such a configuration, the indwelling catheter 1 has a configuration having appropriate slipperiness contributing to improvement in distal end returning property, and can smoothly return to a target indwelling position without damaging the inner wall of the blood vessel at the time of a return operation of the distal end. When the lubricative coating contains an antithrombotic material, generation of thrombus due to indwelling of the shaft 10 is suppressed, and long-term indwelling in a blood vessel becomes possible.
In the indwelling catheter 1 according to the present embodiment, the shaft 10 may contain a polyurethane resin or may contain a silicone resin.
With such configuration, it is possible to manufacture the indwelling catheter 1 having the initial elasticity as the first physical property and the shape restoring rate as the second physical property necessary for improving the distal end returning property.
Hereinafter, while the present invention will be specifically described with reference to Examples, the scope of the present invention is not limited to the following Examples.
Examples and Comparative Examples of the indwelling catheter according to the embodiment of the present invention will be described.
For the indwelling catheters prepared in Examples and Comparative Examples, “initial elasticity,” “shape restoring property,” “sliding resistance,” and “distal end returning rate” were measured as physical properties according to the following test conditions and measurement procedures.
An initial elasticity test is a test in which the initial elasticity of each sample is measured using a test device 100 illustrated in
A shape restoring rate test is a test in which a shape restoring rate of each sample is measured using a test device illustrated in
A sliding resistance test is a test in which sliding resistance of each sample is measured using a test device 300 illustrated in
A distal end returning rate test is a test in which a returning rate before and after movement of a distal end portion of each sample is measured using a test device 400 illustrated in
Table 1 illustrates specifications of each sample used in Examples and Comparative Examples.
A measurement results of Examples and Comparative Examples are illustrated in Table 2.
As illustrated in Table 2, in Examples 1 to 7, the distal end returning rate exceeded 96%. This indicates that, by setting the initial elasticity, which is a physical property of the indwelling catheter, to a range of 0.012 N/mm to 0.13 N/mm, setting the shape restoring rate to 73% or more, and setting the sliding resistance to 0.025 N or less, these physical properties function effectively to enhance the distal end returning property of the indwelling catheter. In particular, in Example 2 and Examples 4 to 6, the initial elasticity was in the range of 0.027 N/mm to 0.036 N/mm, and the shape restoring rate was 79% or more, so that the distal end returning rate was 100%, indicating that more excellent distal end returning properties than those of Examples 1, 3, and 7 can be obtained.
In contrast, as illustrated in Table 2, in Comparative Examples 1 to 10, the distal end returning rate was lower than 96%. This is presumed to be due to the fact that all the physical property values of the initial elasticity, shape restoring rate, and sliding resistance of each Comparative Example do not satisfy the ranges of Examples.
As described above, to improve the distal end returning property in the indwelling catheter, it has been proved that it is effective to set the initial elasticity to the range of 0.012 N/mm to 0.13 N/mm, set the shape restoring rate to 73% or more, set the sliding resistance to 0.025 N or less, and more preferably set the initial elasticity to the range of 0.027 N/mm to 0.036 N/mm, and set the shape restoring rate to 79% or more.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-109463 | Jul 2022 | JP | national |
This application is a bypass continuation of PCT Application No. PCT/JP2023/024553, filed on Jul. 3, 2023, which claims priority to Japanese Patent Application No. 2022-109463, filed on Jul. 7, 2022. The entire contents of these applications are incorporated by references.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2023/024553 | Jul 2023 | WO |
| Child | 19006457 | US |
