JPS6122987B2 - - Google Patents

Description

BACKGROUND TECHNICAL FIELD OF THE INVENTION The present invention relates to extracorporeal circulation of blood, continuous monitoring of blood, continuous blood fractionation, and furthermore, the use of an artificial organ such as an artificial kidney or an artificial lung to collect blood from a patient. This invention relates to an intravascular indwelling catheter that is punctured and fixed into a blood vessel for suctioning, returning, etc. Prior Art Intravascular indwelling catheters generally consist of a tube body with openings at both ends into which an internal needle for vascular puncture is inserted, and a hub portion fixed to one end of the tube body. The tube is used by puncturing the blood vessel with the inner needle inserted, then withdrawing the inner needle, and then indwelling the tube body with the tube further pushed into the blood vessel. Therefore, the tube body of an intravascular indwelling catheter has a certain degree of mechanical strength, can be inserted into a blood vessel, does not easily bend due to external pressure, and can be shaped into a tapered tip. In addition, good biocompatibility is required. Furthermore, in recent years, the wall thickness of this tube body has been made as thin as possible to obtain as much fluid passage as possible even if the outer diameter is the same, and the overall stiffness has been strengthened so that puncturing can be performed reliably. Therefore, there is an increasing demand for the ability to use thicker inner needles. Heretofore, it has been known to use polyethylene, polypropylene, tetrafluoroethylene, fluorinated ethylene/propylene copolymer (FEP), etc. as the material for the tube body of this type of intravascular indwelling catheter. Problems with the Prior Art That is, polyethylene is a common material for tubes placed in blood vessels, and because it is easy to mold into a tube shape and is flexible, it is used as a material that does not easily damage blood vessel walls. However, on the other hand, it has low strength and there is a risk of cutting, and it is also too flexible, so it is difficult to use it as a tube body for an intravascular indwelling catheter that is covered with an inner needle and punctured into a blood vessel. Furthermore, blood clots easily. In addition, polypropylene is strong and hard, so it is suitable as a material for the tube body of an intravascular catheter, and has relatively good moldability. However, it is easy to bend, has low restoring force, and has low bending resistance, so there is a risk that the tube body will become cold and break. Also, blood clotting is likely to occur. Furthermore, FEP is used as a material for tube bodies because it has good moldability, is difficult to coagulate, and has a low incidence of phlebitis. Hardness decreased and satisfactory results could not be obtained. In other words, when a tube body is molded from these conventional plastic materials, if the wall thickness of the tube body is made as thin as necessary, the mechanical strength will be reduced and it will become easier to bend, and the inner needle will be pulled out and only the tube body will be removed. Further, when inserting the tube into the blood vessel, there are problems such as difficulty in manipulating the tube, and conversely, if the tube is made thick enough not to cause problems in handling, the flow rate cannot be increased sufficiently, Another problem was that it was not possible to use a thick inner needle in order to strengthen the overall body so that the puncture could be performed reliably. It is also desired to provide a side hole at the tip of the tube body. This is because the diameter of the distal end of the tube body is smaller than the diameter of the tube body, and it is brought into close contact with the internal needle to reduce the penetration resistance when inserting the intravascular catheter into the blood vessel. The flow rate is restricted due to the small size. This amount will be secured through the side holes. When injecting a drug using an intravascular catheter, if the drug is discharged only from the tip opening of the tube body, the discharge direction will be concentrated at one point, so the higher the concentration of the drug, the more likely it is that the blood vessel wall will become inflamed. Therefore, side holes are provided to disperse the discharge. When blood is circulated outside the body, a pump is used to control the speed of blood circulation outside the body, so negative pressure is applied to the opening at the tip of the tube, which may cause the opening to come into close contact with the blood vessel wall. Therefore, the formation of the side holes prevents negative pressure from being concentrated. This is due to the following reasons. However, it would be better to provide a side hole in the tube body, but in that case, the mechanical strength would be reduced accordingly, making it easier to bend, and the side hole would be deformed by external force, resulting in increased penetration resistance. Currently, it is difficult to provide side holes. Furthermore, in the currently commonly used method of blood dialysis using an artificial kidney, two intravascular indwelling catheters are placed in each of the patient's arterialized veins to perform suction and ring return.
Puncturing a blood vessel with an intravascular indwelling catheter at two locations in this way places a heavy burden on the patient and shortens the life of the shunt, which is not necessarily satisfactory. For this purpose, a method has been developed that uses a double tube structure to simultaneously suck and return blood, and is considered promising. Intravascular indwelling catheters consisting of a tube body with a double tube structure generally consist of an inner tube through which an inner needle is inserted in order to be guided into the blood vessel, and an outer tube that forms an annular passage outside the inner tube. The tube body is connected to a hub, and a side hole communicating with the annular passageway is provided in the side tube at the tip end of the annular passageway. However, when the tube body has a double-tube structure, the wall thickness of the tube body is thinned in order to reduce the outer diameter of the tube body, but during use, the outer tube tends to collapse due to the pressure of the muscles at the puncture site. There are also problems such as the annular passage between the outer tube and the inner tube being closed. Furthermore, since this tube body is placed in a blood vessel, it is necessary to select a material that does not have any effects on the living body such as blood coagulation or toxicity, and there are many problems in selecting the material. Purpose of the Invention The present invention has been made in view of the above circumstances, and has been designed to have exceptional effects and effects compared to conventional intravascular indwelling catheters, that is, to have no adverse effects on the living body, and to The object of the present invention is to form a tube body of an intravascular catheter using a material whose wall thickness can be significantly reduced without significantly impairing mechanical properties. Namely, there is an inner needle for puncturing a blood vessel having a hub portion, and an inner needle having an inner diameter that is open at both ends, has a hub portion fixed to one end, has a tapered shape at the other end, and has the inner needle inside. An intravascular indwelling catheter consisting of a tube body having a length such that the tip of the inner needle protrudes when inserted, the tube body being thin and made of ethylene-tetrafluoroethylene copolymer with a specific gravity of 1.73 to 1.75. Provided is an intravascular indwelling catheter characterized in that it is made of extruded material. Another object of the present invention is to provide a specific invention characterized in that the tube has a double tube structure in which an outer tube and an inner tube are provided concentrically. Furthermore, in the relationship between the outer diameter gauge number G _T of the tube body and the outer diameter gauge number G _I of the inner needle, G _T =G _I −2
(In the formula, G _I is 15≦G _I ≦26, and G _T is 13≦G _T ≦24.) Another object of the present invention is to provide a specific invention characterized in that a side hole is provided at the tip of the tube body. DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below based on an illustrated embodiment. In the figure, reference numeral 1 denotes an intravascular indwelling catheter, which includes a tube body 2 with both ends open, and a hub portion 4 made of polypropylene fixed to one end of the tube body 2 via an adhesive 3 such as epoxy or urethane. It is made up of A side hole 9 may be provided at the tip of the tube body 2. When drilling side holes in the tube body, the drilling operation is easy without crushing. Furthermore, by making the diameter of the tip opening of the tube body 2 smaller than the diameter of the tube body, it is possible to bring the inner needle 5 into close contact with the inner needle 5, thereby reducing the penetration resistance when the intravascular indwelling catheter is inserted into the blood vessel. I can do it. When the inner needle 5 is completely inserted into the tube body 2,
It is necessary to make the tube body 2 to a length such that the tip of the inner needle slightly protrudes from the tip of the tube body 2. This tube body 2 is made of ethylene/tetrafluoroethylene copolymer, that is, the general formula is (-CH ₂ -
It is made by extruding a material having repeating units of _CH2 - _CF2 - _CF2 )-. Therefore, the tube body can be made thinner. In other words, the inner needle can have a gauge number (outer diameter indication) of the tube body plus 2 gauges. Therefore, compared to conventional intravascular indwelling catheters, it can pass a larger flow rate, and despite its thinner wall, it has sufficient mechanical strength such as bending strength, and even when punctured, the inner needle is thicker. Therefore, the back of the catheter placed in the blood vessel becomes strong and stable. Further, even if a side hole is provided at the tip of the tube body 2, the tube body 2 has sufficient mechanical strength and is stable. Furthermore, it has good biocompatibility. Furthermore, the material of the present invention can be extruded and therefore easily manufactured. This ethylene/tetrafluoroethylene copolymer is manufactured by ASTM (American Standard Testing).
Method - American Standard Test Method - hereinafter abbreviated as ASTM. ), specific gravity is 1.73 to 1.73.
1.75, and when tested according to ASTM D785, a hardness of about R45 to 55 is appropriate, and preferably R50. Further, the physical properties of the material of the tube body 2 will be detailed as follows. Tensile strength: 410 Kg/cm ² or more (Tested according to Japanese Industrial Standard K6891. Test methods in brackets below are compliant), Elongation: 330% or more (Japanese Industrial Standard K6891), Flexural modulus: 10 x 10 ³ Kg/cm Mechanical strength of ² or above (ASTM D790), melting point below 270℃, tensile modulus 8Kg/cm ²
The friction coefficient against stainless steel is preferably 0.2 or less (ASTM D638). It is neither obvious nor clearly foreseeable that adoption of these requirements will have the necessary functionality to achieve the objectives of the present invention. This ethylene/tetrafluoroethylene copolymer has been tested for acute toxicity, intramuscular implantation, and intradermal reaction (United States Pharmacopoeia, 19th edition, Biological Tests for Plastic Containers), as well as hemolysis (Japanese Pharmacopoeia). , 9th Revised Plastic Container Standards for Infusions), it was confirmed that there were no problems in either case. Ethylene/tetrafluoroethylene is thus inert to living organisms and has relatively high mechanical strength such as bending strength, making the wall thickness of the tube body 2 significantly smaller than in the case of conventional materials. It was also found that the surface of the molded product has good smoothness, and when the catheter 1 is pushed into a blood vessel, there is little frictional resistance with the skin, and smooth insertion is possible. In addition, fluorinated ethylene propylene copolymer (abbreviated as FEP) is conventionally considered the most preferable.
The specific gravity of the intravascular indwelling catheter made from
2.17 to 2.17 (ASTM D792), hardness R25 (ASTM
D785), tensile strength is 189-220Kg/cm ² (Japanese Industrial Standard K6891), flexural modulus is 6.7×10 ³ Kg/cm ²
(ASTM D790). Therefore, the tube body of the intravascular indwelling catheter of the present invention has various special effects compared to FEP as described above. When using this intravascular indwelling catheter 1, as shown in FIG. 2, and the transparent hub 6 is fitted into the lumen 8 of the hub portion 4 of the intravascular catheter 1. When the puncture needle 7 is fully fitted into the intravascular indwelling catheter 1 in this way, the tip of the inner needle 5 is inserted into the tube body 2.
It will be slightly protruding from the tip. However,
In this state, puncture the blood vessel wall. When the needle is completely punctured, blood flows into the inner needle 5. and,
After confirming that blood has reached the hub portion 6, the tube body 2 is pushed into the blood vessel by the required length using the inner needle 5 as a guide, and then the puncture needle 7 is pulled out. Since the diameter of the distal end of the tube body 2 is closed smaller than the pipe diameter of the tube body, it is in close contact with the inner needle 5, and the distal end is formed in a tapered shape, insertion of the tube body is smooth. Furthermore, the wall thickness of the tube body is made thinner, and the coefficient of friction against stainless steel is also made smaller. Therefore, the inner needle can be easily inserted and withdrawn from the tube body, and the intravascular indwelling catheter can be safely inserted and indwelled. Furthermore, if necessary, only the intravascular indwelling catheter 1 can be pushed into the blood vessel, thereby making it possible to maintain the intravascular indwelling state well. Although the tube body 2 has a thin wall thickness, it has mechanical strength, does not easily bend under external pressure, and is strong, so puncturing can be performed reliably. It also has good biocompatibility. Furthermore, even if the outer diameter of the tube body 2 is the same as that of the conventional tube body 2, a larger amount of fluid can flow. Next, we will discuss test results comparing the relationship between the wall thickness and bending strength of the tube body of the intravascular indwelling catheter according to the present invention with a catheter made from FEP, which is conventionally considered the most preferable catheter. First, as shown in Table 1, the intravascular indwelling catheter of the present invention with a gauge number of 18G (outer diameter) (A) and the conventional FEP
Comparative tests were conducted on bending strength using a product (B) with a gauge number of 18G (outer diameter) made by Manufacturer.

[Table] The results are shown in Figure 2. In this comparative test, each tube body was held horizontally, and then a 5g weight was suspended from the tip of each tube body, and the hanging distance (mm) from the horizontal position of the tip of each tube body was varied by changing the distance from the tube fulcrum. It was measured while As is clear from this test result, the conventional
Gauge number 18G made from FEP, inner needle gauge number
When compared with the product (B) of No. 21, the product (A) of the present invention has a higher bending strength even though the wall thickness is significantly smaller than that of the product (A). Therefore, it is clear that the bending strength of the tube body according to the present invention is significantly improved. From the results of such tests, it was confirmed that the tube body according to the present invention allows the use of an inner needle with a smaller gauge number than conventional ones. For example, Table 2 below shows the relationship between the gauge number of the tube body and the gauge number of the inner needle that can be used in the tube body.

[Table] In other words, in the relationship between the gauge number G _T of the tube body and the gauge number G _I of the inner needle, G _T = G _I −2 (in the formula, G _I is 15≦G _I ≦26, and G _T is 13≦ G _T ≦24). In conventional products, considering the mechanical strength of the tube body, for example, the gauge number of the tube body is
For 18G, 20G, and 22G, it was necessary to make the tube body thick enough to require the gauge numbers of the inner needle to be 21G, 24G, and 28G, respectively. This means that the smaller the outer diameter of the tube, the thinner the inner needle must be, and as a result, the blood flow cannot be obtained effectively and the inner needle becomes thinner. This means that the inner needle loses its elasticity and lacks stability when puncturing. On the other hand, the needle of the present invention can employ an inner needle having a gauge number plus two gauges of the tube body. Therefore, a larger flow rate can be passed per unit time, a thicker inner needle can be used, so the stiffness during puncturing is strong, and mechanical strength is sufficient despite the thinning of the tube body. It can be done. It is clear that these effects are unexpectedly effective and quantitatively enhanced. Next, an example in which the present invention is applied to an intravascular indwelling catheter having a double tube structure will be described. 3 and 4 show an example of an intravascular indwelling catheter according to the present invention, for example,
A hub 10 made of polycarbonate resin or the like and made by injection molding, and a proximal end processed into a funnel shape at the distal end of the hub 10 are attached together with an outer hub 11, and the other end forms a tapered tip 12. An inner tube is disposed through the axis of the outer hub 11 and the tube body 13, and an inner needle 14 is disposed through the axis of the inner tube.
is now inserted. That is, the tube body 13 has an inner passage 15 through which the inner needle 14 is inserted.
An annular passage 18 is formed between an inner tube 16 forming an inner tube 16 and an outer tube 17 concentrically disposed outside the inner tube 16. The inner tube and outer tube can be made by extrusion molding. One or more side holes 19 are provided in the preemption start portion 21 at the distal end of the outer tube 17, and the annular passage 18 is provided with one or more side holes 19.
It communicates with The size of the side holes is preferably such that the total opening area thereof is approximately equal to or larger than the area of the annular passage. Furthermore, the outer tube 17 and the inner tube 1
6 is melted and fused at its tip by a heat mold to form a tube body having an inner passage having a tapered tip and an annular passage. Note that the method of fixing the inner tube 16 and the outer tube 17 to the respective hubs 10 and 11 may be by adhesion with epoxy resin or the like, or by insert molding, in addition to caulking. That is, the hubs 10 and 11 may be integrated. Next, a method of using the intravascular indwelling catheter having a double tube structure will be described. First, before piercing the blood vessel, the inner needle is inserted into the tube body and integrated. Since the coefficient of friction between the inner surface of the tube body and the outer surface of the inner needle made of stainless steel is small, it can be inserted smoothly. This friction coefficient is preferably 0.2 or less. Next, when inserting the intravascular indwelling catheter into the blood vessel, the exposed tip portion of the inner needle is inserted into the blood vessel. When the needle is completely penetrated, blood flows into the inner needle and reaches the inside of the hub 20. After confirming whether the tip of the inner needle 14 is reliably located within the blood vessel, the tube body 13 is pushed in using the inner needle as a guide. The distal end of the tube body 13 is tapered so that it can be smoothly inserted into a blood vessel. Make sure that the side hole 19 at the tip of the tube body completely enters the blood vessel. Even though the tube body 13 has the same outer diameter as the conventional one, its thin wall allows for a large fluid flow rate, and it also has mechanical strength and does not bend easily due to external pressure, so it does not easily enter the blood vessel. Insertion is safe and easy. Furthermore, the tube has one or more side holes at its tip, which has mechanical strength and good stiffness, so it can be inserted reliably without breaking or bending. Next, hold the hub lightly with your fingers and pull out the inner needle. As mentioned above, the tube body is thin, has a large blood flow rate, and has mechanical strength due to its material, so even when the tube body is indwelling in the blood vessel, it is difficult to aspirate and return blood from the patient, for example. It is effective and safe while performing. The tapered tip 12 at the tip of the tube body is made of the same material and is integrally molded, so even when inserted into a blood vessel, the tube body can be inserted smoothly without being compressed and deformed inward by the epidermis and tissue. I can do it. As detailed above, according to the present invention, by using an ethylene/tetrafluoroethylene copolymer as the tube body of an intravascular catheter, the tube body can be made thinner.
Therefore, compared to conventional catheters of this type, a larger flow rate can be passed per unit time, and because a thicker inner needle can be used, the stiffness during puncture is strong, and the bending strength is strong despite the thinness of the catheter. It is possible to provide an intravascular indwelling catheter that has many advantages such as having a practically sufficient mechanical strength such as the mechanical strength of the present invention, and having no adverse effects on the living body. In addition, especially when the ethylene/tetrafluoroethylene copolymer is used in the double-tube structure tube according to the present invention, it is possible to effectively prevent the outer tube from collapsing due to muscle pressure at the puncture site during use. However, the advantages are especially great because the annular passage between the outer tube and the inner tube is not blocked. Further, although the tube body is provided with a side hole, the tube body has mechanical strength and has good stiffness, so the tube body can be inserted reliably without being damaged or bent. Further, there is an advantage that the drilling operation when drilling a side hole in the tube body is facilitated because the tube body is not crushed. Furthermore, in the relationship between the gauge number G _T of the tube body and the gauge number G _I of the inner needle, G _T =G _I −2 (where G _I is 15≦G _I ≦26, G
Since _T can be set such that 13≦G _T ≦24), a larger flow rate can be passed per unit time. In addition, since a thick inner needle can be used, it is strong during puncturing, and the mechanical strength can be made sufficient despite the thinning of the tube body. These effects by adopting the ethylene/tetrafluoroethylene copolymer could not have been predicted based on the current state of the art, and have been increased effectively and quantitatively to an unexpected extent.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an intravascular indwelling catheter according to the present invention, FIG. 2 is a diagram showing the bending strength of the indwelling intravascular catheter of the present invention in comparison with a conventional example, and FIG.
This figure is a side view of an intravascular indwelling catheter according to another embodiment of the present invention, and FIG. 4 is a side view with the distal end of the tube body shown in FIG. 3 partially cut away. In the figure, 1... Intravascular indwelling catheter, 2... Tube body, 3... Adhesive, 4... Hub portion, 5...
Inner needle, 6...Transparent hub, 7...Puncture needle, 8...Inner lumen, 9...Side hole, 10...Hub, 11...Outer hub, 12...Tapered tip, 13...Tube body , 14...inner needle, 15...inner passage, 16...
Inner tube, 17... Outer tube, 18...
Annular passage, 19... side hole, 20... hub, 21...
...Tapering start part.

Claims (1)

[Scope of Claims] 1. An inner needle for puncturing a blood vessel, which is provided with a hub portion, has both ends open, has a hub portion fixed to one end, and has a tapered shape at the other end, into which the inner needle is inserted. An intravascular indwelling catheter comprising a tube body having an inner diameter of 100 mm and a length such that the tip of the inner needle protrudes when the inner needle is inserted, the tube body comprising:
1. An intravascular indwelling catheter characterized by being thin and extruded from an ethylene/tetrafluoroethylene copolymer having a specific gravity of 1.73 to 1.75. 2. The intravascular indwelling catheter according to claim 1, wherein the tube body has a double tube structure in which an outer tube and an inner tube are provided concentrically. 3 In the relationship between the outer diameter gauge number G _T of the tube body and the outer diameter gauge number G _{I of} the inner needle, G _T = G _I −2 (in the formula, G _I is 15≦G _I ≦26, G The intravascular indwelling catheter according to claim 1, wherein _T ≦24. 4. The intravascular indwelling catheter according to claim 1 or 2, wherein a side hole is provided at the distal end of the tube body.