MXPA00002547A - An intravenous catheter assembly and a method of making a combination hub and catheter - Google Patents

Abstract

According to one aspect of the invention a method is provided for making a combination hub and catheter. A material is molded into a body having at least a first hub, and at least a first nose extending from the first hub. The first nose is then elongated into a catheter.

Description

AN ASSEMBLY OF INTRAVENOUS CATHETER AND A METHOD TO MANUFACTURE A COMBINED CENTRAL PART AND CATHETER BACKGROUND OF THE INVENTION FIELD OF THE INVENTION This invention relates to a method for manufacturing a combined central part and a catheter, as well as an intravenous catheter assembly.

RELATED PREVIOUS TECHNIQUE Catheter assemblies are often used to pass fluids between a device such as a syringe or container to receive drops to or from body lumens such as veins or arteries, or other internal targets. This type of assembly usually includes a central part, a catheter and a needle. Commonly, an eyelet ring is inserted into the catheter. The catheter, together with the eyelet ring, is inserted in turn into an opening in the nose or tip of the central part and the eyelet ring snaps into the inside of the tip of the central part. Subsequently, a needle is inserted into the catheter. A body lumen is drilled through the sharp tip of the needle so that the catheter and needle have access to it. Once the catheter and needle are inside the body lumen, the needle is removed. Next, a syringe or a drop tube is connected to the central part to receive drops to enable the passage of fluids through the central part and the catheter, between the receiving container or the syringe, and the lumen. bodily. Normally, the central part is made of a material that provides sufficient rigidity and the catheter is made of a flexible material, at least when it is inserted into the body lumen and exposed to the prevailing humidity inside it. The method described above by which the catheter is connected to the central part is inconvenient, expensive and requires complex assembly machines.

BRIEF DESCRIPTION OF THE INVENTION In accordance with one aspect of the invention, a method for the manufacture of a combined central part and a catheter. A material is molded into a body having at least a first central part and at least one first tip protruding from that first central part. The first tip extends into the catheter. The central part can have a Luer closure. The catheter can have a length of at least 12 mm, preferably at least 18 mm, and most preferably at least 30 mm.

The catheter can have an outer diameter between 0.37 mm and 3.7 mm. Preferably, the catheter is flexible enough to fit a curved body lumen when it is inserted into it. The material can be a polyamide such as nylon, a mixture of acrylonitrile / butadiene / styrene and polyurethane, polyetheramide, polypropylene, and ethylene-propylene copolymers, polyurethane or a mixture of a polyamide and a polyether amide. Preferably, the tip is elongated or stretched at a temperature at which the material is malleable. Preferably, the catheter is rigid at room temperature and flexible when exposed to moisture and body temperature. Preferably, the body has a second central part, and a second tip protruding from that second central part, characterized in that one end of the first tip remote from the first central part joins another end of the second tip remote from the second part. central, and both the first tip and the second tip extend, respectively, into the interior of a first catheter and a second catheter. The method may further include the step of separating the first and second catheters from each other.

It is possible to mold a variety of bodies simultaneously, and the first and second tips of each of these various bodies can be elongated simultaneously. The bodies can be molded in a mold mounted on a rotating table, which is rotated so that the mold is located in a first station. The method can include the step of rotating the turntable so that the mold is moved to a second station where the first and second tips of each of the various bodies will be elongated. The method may include the steps of rotating the rotary table so that the mold is moved to a third station, and for the bodies to be ejected from the mold while it is in the third station. The invention also relates to a mold for making a combined central part and a catheter, and the mold includes a first component and a second component. The first and second components define a volume within which a material can be injected so that this material assumes the shape of the central part and the tip. The central part may be connected to the first component and the tip connected in turn to the second component so that the tip extends into the catheter when the first and second components are separated from each other.

The volume may include a first volume of the central part in the first component, a second volume of the central part in the second component, and a channel or conduit of the tip communicating to the first volume of the central part with the second volume of the central part. The material in the tip channel can be extended when the first and second components are separated from each other. The first and second components can define a diversity of these volumes. The invention also relates to an intravenous catheter assembly that includes a hollow central part, a catheter and a needle. The catheter has a length of at least 12 mm, a first end forming a unitary structure with the central part, a second end distant from the central part, and a channel extending from the central part to the exterior of the second end. The needle, which can be excised, is located within the canal and has a sharp tip near the second end of the catheter. Preferably, the central part and the catheter are made of the same material.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is described in more detail by means of examples with reference to the drawings appended hereto, characterized in that: Figure 1 is a side view of a longitudinal section of a mold that is used to make a combined central part and catheter in accordance with one embodiment of the invention; Figure 2 is a view similar to that of Figure 1 after a second component of the mold is displaced relative to a first component thereof, to elongate the tip of a body formed by the mold illustrated in Figure 1, towards the inside of the catheter; Figure 3 is a side view of a longitudinal section of a combined central part and catheter made in accordance with the method illustrated in Figure 1 and Figure 2; Figure 4 illustrates an intravenous catheter assembly, including the combined central part and catheter, once they have been inserted into a body lumen; Figure 5 illustrates a combined central part and catheter once the needle of the assembly illustrated in Figure 4 has been removed therefrom and the catheter that is part of the combined central part and catheter assumes or adapts to the natural shape of the body lumen; Figure 6 is a side view of a longitudinal section of a mold that is used to make two combined central parts and catheters in accordance with another embodiment of the invention; Figure 7 is a view similar to that of Figure 6, once the second component of the mold has been displaced relative to a first component thereof to stretch the tips of a body, formed in the mold of Figure 6, into the respective catheters; Figure 8 is a side view of a longitudinal section of two combined central parts and catheters made in accordance with the method illustrated in Figures 6 and 7; Figure 9 illustrates a mold in which various central parts and combined catheters can be made; and Figure 10 is a plan view or horizontal projection of an apparatus that is used for the manufacture of combined central parts and catheters in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 of the accompanying drawings illustrates a mold 10 which is used to make the combined central part and catheter. The mold 10 includes a first component 12, a second component 14 and a central barrel 16. The first component 12 has an opening formed therein with a lower part, or first volume of the tip 18, with a relatively small diameter, and an upper part, or volume of the central part 20, with a relatively large diameter. The upper part 20 is slightly enlarged in a mouth 22 at the top of it. An opening is formed in the second component, which has an upper part, or second volume of the tip 24, having a diameter equivalent to the lower part 18 of the first component 12, and a lower part 26 which is smaller than the upper part 24. The second component 14 is located below the first component 12 so that the surfaces of the first and second components 12 and 14 make contact with each other, and the lower part 18 of the first component 12 is aligned with the upper part 24 of the second component 14. The central barrel 16 has a bottom 28, a trunk 30 extending from the bottom, and this trunk 30 has a relatively large diameter, and a barrel 32 extending from the trunk 30, and this barrel 32 has a relatively small diameter with respect to the trunk 30. The barrel 32 is inserted into the upper part 20 of the first component 12 and from there towards the interior of the lower part 18 of the first component 12, the upper part 24 of the second component 14 and through the lower part 26 of the second component 14 so that the ca The nose 32 protrudes from the second component 14. In this way, the trunk 30 is located within the upper part 20 of the first component 12. The first and second components 12 and 14 together with the central barrel define a volume 34 around this central barrel. and inside the openings in the first and second components 12 and 14, but excluding the part that is between the barrel 32 and the lower part 26 of the second component 14. A material 36 is injected into the interior of the volume 34 until this material 36 completely fills the volume 34. The material 36 is above its melting point and above, also, from the ambient temperature, and is preferably also chromium-coded. Subsequently, the material inside the volume 34 is allowed to cool to a temperature below its melting point, but still above the temperature at which the material becomes malleable and above room temperature. In this way, a malleable body 40 is molded into the interior of the mold 10, and this body 40 has a central part 42 and a tip 44 extending from the central part 42. The central part 42 is formed inside the upper part. 20 of the first component 12 and the tip 44 is formed in the lower part 18 of the first component 12 and the upper part 24 of the second component 14. An extension or groove 46 is formed very low inside the upper part 24 of the second component 14 and the material fills the notch 46 so that the tip 44 has a rib or rib 48 located inside the notch 46. As illustrated in Figure 2, the second component 14 is removed from the first component 12 together with the barrel 32 while the material retains its malleable condition. The rib 48 engages the inside of the notch 46 so that the tip 44 of Figure 1 is elongated or stretched toward the interior of the catheter 50. The outer diameter of the tip 44 reduces its size while the tip is stretched. into the catheter 50 to form an outer diameter 52 of the catheter 50. The internal diameter 54 of the catheter 50 is generally determined by the external diameter of the barrel 32.

It is also possible to control the diameter 54 more accurately by controlling the stretch rate of the catheter 50 and by heating or cooling the catheter 50 when it is being formed. It is also possible to selectively warm or cool the catheter 50 at various points along it when it is being formed, in order to selectively modify the diameters 52 and 54 along the catheter. By maintaining, for example, the lower part of the catheter 50 at a temperature lower than that of the rest of the catheter 50, the lower part may have an external diameter smaller than that of the upper part of the catheter 50, so that the external surface of the catheter it is sharpened inwards in the lower part of it, or it is bevelled. Subsequently, the second component 14 is released from the catheter 50. The central barrel 16 is extracted from the catheter 50 and from the central part 42 by a pull. The barrel 32 extends slightly only towards the interior of the catheter 50, thus facilitating its release from the catheter 50. The central part 42 and the catheter 50 are then removed from the first component 12. The combined central part and catheter 56 with Figure 3 are characterized in that they include a central part 42 and a catheter 50. The combined central part and catheter 56 are cooled to room temperature, which is lower than the temperature at which the material becomes malleable. An important advantage is that the combined central part and catheter 56 are manufactured in accordance with a simple and inexpensive method that does not require the assembly of a catheter and a central part by the use of complex assembly equipment or procedures.

The central part 42 has a Luer closure 58 on one side thereof opposite the catheter 50, and a first channel 60 passing through it. The catheter 50 has a first end 62 which is fixed to the central part 42 in a unitary structure, in the sense that the central part 42 and the catheter 50 are made of a single component, that is, without an interconnection between a component with which is formed by the central part 42 and another component with which the catheter 50 is formed. The catheter 50 is cut just above the rib 48 to release or release the catheter 50 from the rib 48. A second end 64 of the catheter 50 is located away from the central part 42. A second channel 66 is formed through the catheter 50 and extends from the first channel 60 of the central part 42, through the catheter 50, to exit the second end 64. The catheter 50 it has an outer diameter 52, an internal diameter 54 and a length 68. The material of the combined central part and catheter 56 is chromocoded, and the color of the combined central part and catheter 56 depends on the caliper or thickness of the catheter 50. In The following table describes different central parts and combined catheters, characterized in that the dimensions are expressed in millimeters.

Figure 4 illustrates an intravenous catheter assembly 76 in accordance with one embodiment of the invention, which includes a combined central part and catheter 56, and a needle assembly 78. The needle assembly 78 includes a body, a transparent chamber for the rectification of the fluid 80 and a needle 82. The needle has a first end 84 which is fixed to the chamber 80, and a second end 86, which has a sharp tip at the far end of the chamber 80. The needle 82 has a channel formed therethrough and communicating with the confines of the chamber 80. A calibrator plug 88 closes the open end of the chamber 80 opposite the needle 82. The second end 86 is first inserted inwardly from the central part 42, and from the central part 42 through the catheter 50 until the second end 86 protrudes from the second end 64 of the catheter 50, remaining near the second end 64 of the catheter 50.

In practice, the second end 86 of the needle 82 is used to pierce a body 90 lumen like a vein or artery, so that an opening 92 is formed towards the interior of the body lumen 90. Subsequently, the catheter 50 is inserted together with the needle 82 into the body lumen 90 through the opening 92. As stated above, the catheter may have a conical or beveled shape at its second end 86. Thanks to this sharp or bevelled shape of end 86, the catheter can more easily penetrate the lumen 90 than if it lacked the above-mentioned shape. The plug 88, due to its porosity, allows ventilation of the air coming from inside the chamber 80, so that the fluid inside the lumen 90 can pass through the needle 82 towards the interior of the chamber 80, where it is It is possible to see the fluid through a transparent wall of the chamber 80. As illustrated in FIG. 5, the needle assembly 78 of FIG. 4 is then removed from the combined central part and the catheter 56. Subsequently, another device 94, such as a syringe or a drip tube of a container for receiving drops, to the Luer closure 58. Thereafter, it is possible to pass the fluids through the central part and the catheter 50 between the body lumen 90 and the device 94. It is possible that the lumen 90 has a natural curved shape as illustrated in Figure 5. Preferably, the catheter 50 is made of a relatively strong material when inserted into the lumen, but flexible enough to be able to er adopt the natural form of the body lumen 90 once it is inserted into the interior of the body lumen 90 and the needle 82 is removed. As will be seen below, certain materials are rigid at room temperature and in dry conditions, but are hydrophilic , so that catheter 50 becomes sufficiently flexible upon contact with higher temperature and humidity conditions, such as those prevailing generally within a body lumen. Preferably, the catheter material 50 should also be able to remain inside the lumen for at least 24 hours, most preferably for up to 72 hours. Since the central part 42 and the catheter 50 are made of the same material, the materials should be strong enough to provide the necessary stiffness to the central part 42. A material that can be used to make the combined central part and catheter 56 It is a polyamide such as nylon 6, nylon 66, nylon 11 or nylon 12. In addition, a polyamide is easy to mold and stretch. Polyamides are also materials to which color can be added easily. A central part and a catheter such as those described above and made of polyamide have a central part rigid enough when ribs or other ribs are placed to strengthen it, and with a catheter sufficiently flexible to be able to take the form of a curved body lumen. In particular, a polyamide is hydrophilic, so that it becomes more flexible upon contact with heat and humidity. Another material that can be used for the central part and the combined catheter described above is a mixture of acrylonitrile / butadiene / styrene (ABS) and polyurethane resins, such as the material that is marketed under the name PREVAIL 3050, PREVAIL 3100 or PREVAIL 3150, manufactured by Dow Chemicals of Midland, Michigan. The PREVAIL can be easily colored, molded and stretched. A central part made of PREVAIL is rigid enough when it has ribs or ribs that strengthen it, and a catheter formed with PREVAIL is flexible enough to take the shape of a curved body lumen. In particular, PREVAIL is hydrophilic so that it becomes more flexible when exposed to moisture and heat. Other materials that can be molded and stretched with ease are fluorinated ethylene-propylene copolymers (FEP). The FEP is flexible enough to take the shape of a curved body lumen. The EFF also provides a sufficiently rigid central part, and a hydrophilic catheter that becomes flexible when in contact with moisture and heat. However, other materials mentioned herein are easier to chromocode than FEP. Yet another material that can be used for the manufacture of the combined core and catheter described hereinabove is polyurethane. The polyurethane provides a sufficiently rigid central part when ribs and other ribs are added to strengthen it, and a catheter which, in general, is flexible enough for the objects to obtain a catheter with the desired flexibility characteristics. Polyurethane is also hydrophilic, so it becomes more flexible when exposed to heat and moisture. The polyurethane can also be easily chromed, molded and stretched. Another material that can be used to make the combined central portion and catheter 56 of the type described herein above is polyether amide, such as that sold under the name PEBAX, manufactured by Elf Atochem of Philadelphia, Pennsylvania. The PEBAX has characteristics similar to those of nylon. It is also possible to use polypropylene to make a combined central part and a catheter as described above. The polypropylene generally has sufficient stiffness to give rigidity to the central part of this type of combined central part and catheter. Polypropylene catheters are relatively rigid in general, but it is possible to use them for certain objects in particular. Other materials such as ethylene-propylene copolymers can be used. These copolymers have characteristics similar to those of the ethylene and propylene described above and, depending on the respective amounts of ethylene and propylene used, sufficiently rigid central parts and sufficiently flexible catheters are obtained. Another material that can be used is a mixture of PEBAX and a polyamide that, depending on the proportions used in the mixture, can provide certain characteristics of PEBAX that are superior to polyamide and other characteristics of polyamide that are superior to the PEBAX.

Figure 6 illustrates another mold 100 that can be used to make two central parts and catheters combined. The mold 100 includes a first component 102, a second component 104, a first central barrel 106 and a second central barrel 108. The first component 102 has an opening formed therein with a lower portion 110 having a relatively small diameter and an upper part 102 having a relatively large diameter. The upper part 112 is slightly enlarged at its upper end 114. The first central barrel has a trunk 118 with a relatively large diameter, and a barrel 120 extending from the trunk, and this barrel 120 has a relatively small diameter with respect to the of the trunk 118. The first component 102 includes a first and second part 122 and 124 which as a whole define a capsule or open chamber only in the lower part 110. In order to place the first central barrel 106 inside the first component 102, the first and second parts 122 and 124 of the first component must be separated. Subsequently, the central barrel 106 is inserted and the first and second parts 122 and 124 are brought together so that the first central barrel 106 is located within the first component 102. The first component 102 and the first central barrel 106 define a first volume of the central part 128 and a first volume of the tip 130.

The second component 104 and the second central barrel 108 have exactly the same structure as the first component 102 and the first central barrel 106, respectively. The second component 104 and the second central barrel 108 define a second volume of the central part 132 and a second volume of the tip 134. The first and second components 102 and 104 are initially located next to each other so that the first and second volumes of the tips 120 and 124 are located one above the other and the barrels 120 of the first and second central cannons 106 and 108 have contact with each other. Accordingly, a volume 136 is defined which includes the first and second volumes of the central portion 128 and 132, as well as a tip channel defined by the first and second volumes of the tip 130 and 134 as a whole. A material 138 is injected into the interior 136 so that the material 138 flows into the volumes of the central part 128 and 132 and the volumes of the tip 130 and 134. The material inside is allowed to solidify. of the volume 136, whereby the body having a first central part 140 is formed in the first volume of the central part 128, a second central part 142 in the second volume of the central part 132, a first tip 144 in the first volume of the tip 130 and a second tip 146 in the second volume of the tip 134. While the material is still malleable, as illustrated in Figure 7, the first and second components 102 and 104 are separated from one another. The first tip 144 is drawn into the interior of the first catheter 148, and the second tip 146 is drawn into the interior of the second catheter 150. The ends of the first and second catheters 148 and 150 are joined together. The first and second parts 122 and 124 are then separated from each other, and the central cannons 106 and 108 are removed. Next, the first and second catheters 148 and 150 are separated to leave two combined central portions and catheters, 152 and 154 respectively, as illustrated in FIG. 8. Each combined central part and catheter 152 or 154 is equal to the central part. and combined catheter 56 which is illustrated in Figure 3. The material used to make the combined central portion and catheter 152 and 154 may be the same as that used to make the combined central portion and catheter 56 shown in Figure 3, and the way in which the combined central part and catheter 152 and 154 are created including the mold that is used for its manufacture, is the same in all aspects of the combined central part and catheter 56 of Figure 3. Figure 9 illustrates another mold 160 including first and second components 162 and 164 respectively. The mold 160 defines a diversity of volumes 166. Each volume 166 is equal to volume 136 of Figure 6. The bodies are molded simultaneously into each of the volumes 166 and the tips of all the bodies are also elongated. simultaneously. An advantage of using the mold 100 of figure 6, and specifically the mold 160 of Figure 9, is that it is possible to manufacture, in a same cycle, more combined central parts and catheters. Figure 10 illustrates the manufacturing apparatus 170, which includes a rotary table 172, a mold 160 similar to the mold 160 of Figure 9, an injection molding machine 174, a pulling or pulling apparatus 176, a cutter and ejector apparatus 178 and a sealing or sealing apparatus 180. The mold 160 is mounted on the rotating table 172. The injection molding apparatus 174, the pulling apparatus 176, the cutting and ejecting apparatus 178 and the sealing apparatus 180, are respectively located first, second, third and fourth stations around the rotary table 172. Initially, the rotary table 172 rotates so that the mold 160 is in the first station, where material is injected thereinto. Subsequently, the rotary table 172 rotates approximately 90 ° so that the mold 160 moves and is located in the second station, where the traction apparatus 176 stretches the tips towards the interior of the catheters. Then, the rotary table 172 rotates around 90 ° to a third station so that the cutting and ejecting apparatus 178 removes the bodies from the mold 160 and subsequently divides or cuts the catheters that are joined together. Next, the rotary table 172 rotates again about 90 ° until the mold 160 is located opposite the fourth station where the sealing apparatus 180 rejoins the first and second components 162 and 164 of the mold 160 with each other. After this, the mold 160 is ready to restart the injection step in the first station.

In another embodiment, the bodies can be ejected from the injection molding machine and placed in a stretching machine such as a universal testing instrument by Instron, so that they can be stretched by the stretching machine under optimally controlled conditions. Although various examples of modalities have been described and illustrated in the appended drawings, it should be noted that these embodiments of the present invention are merely illustrative but not limiting, and that this invention is not limited to the specific structures and arrangements illustrated and described, since those skilled in the art can make some modifications.

Claims (25)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for making a combined central part and a catheter, which includes: molding a material to form a body having at least a first central part, and at least a first tip protruding from that first central part; and lengthen the first tip into a catheter.

2. A method according to claim 1, further characterized in that the central part has a Luer lock.

3. A method according to claim 1, further characterized in that the catheter has a length of at least 12 mm.

4. A method according to claim 1, further characterized in that the catheter has a length of at least 30 mm.

5. A method according to claim 1, further characterized in that the catheter has an external diameter between 0.37 mm and 3.7 mm.

6. A method according to claim 1, further characterized in that the catheter is flexible enough to conform to a curved body lumen, when it enters the interior of that body lumen.

7. A method according to claim 1, further characterized in that the material is selected from a group including a polyamide, a mixture of acrylonitrile / butadiene / styrene and polyurethane, a polyether amide, a fluorinated ethylene-propylene copolymer, polypropylene, an ethylene-propylene copolymer, polyurethane, and a mixture of a polyamide and a polyether amide.

8. A method according to claim 1, further characterized in that the tip is elongated at a temperature at which the material becomes malleable.

9. A method according to claim 1, further characterized in that the catheter is rigid at room temperature and flexible when exposed to moisture and body temperature.

10. A method according to claim 1, further characterized in that (i) the body has a second central part, and a second tip extending from the second central part, one end of the first tip that is moving away from the first central part is joined to another end of the second point that is remote from the second central part, and (ii) the first and second central parts are separated so that both the first point and the second point extend, respectively, towards the inside the first catheter and the second catheter, and this method further includes: separating the first and second catheters from each other.

11. - The method according to claim 10, further characterized in that: there is a diversity of bodies that are molded simultaneously; and the first and second tips of each of the different bodies are elongated simultaneously.

12. The method according to claim 11, further characterized in that the bodies are molded in a mold mounted on a rotating table when this table rotates to place the mold in a first station, and this method includes: rotating the rotary table so that the mold moves towards a second station, where the first and second tips of each of the various bodies are elongated.

13. The method according to claim 12, further characterized in that: the rotating table rotates so that the mold moves to a third station, where the first and second catheters are cut during the stay of the mold in this third station.

14. The method according to claim 12, further characterized in that: the rotating table rotates so that the mold moves towards the third station; and the bodies are expelled from the mold during the latter's stay in the third station.

15. A mold for making a combined central part and a catheter, and this mold includes: a first component; and a second component, and this first and second components define a volume within which material can be injected so that this material takes the form of a central part and a tip, with the central part connected to the first component and the tip connected to the second component so that the tip extends into the catheter when the first and second components are separated from each other.

16. The mold according to claim 15, further characterized in that the volume includes a first volume of the central part in the first component, a second volume of the central part in the second component, and a channel of the tip from the first volume of the central part towards the second volume of the central part so that the material contained in the tip channel extends when the first and second components are separated from each other.

17. The mold according to claim 16, further characterized in that the first and second components define a diversity of volumes.

18. An intravenous catheter assembly that includes: a hollow central part; a catheter with a length of at least 12 mm, a first end fixed to the central part in a unitary structure, a second end remote from the central part, and a channel extending from the central part until it leaves the second end; and a needle, which is located within the canal and can be removed, with a sharp tip near the second end of the catheter.

19. - An intravenous catheter assembly according to claim 18, further characterized in that the central part and the catheter are made of the same material.

20. An intravenous catheter assembly according to claim 18, further characterized in that the central part has a Luer lock thereon.

21. An intravenous catheter assembly according to claim 18, further characterized in that the catheter has a length of at least 30 mm.

22. An intravenous catheter assembly according to claim 18, further characterized in that the catheter has an external diameter of between 0.37 mm and 3.7 mm.

23. An intravenous catheter assembly according to claim 18, further characterized in that this catheter is flexible enough to conform to a curved body lumen as it penetrates that body lumen.

24. An intravenous catheter assembly according to claim 18, further characterized in that the material is selected from a group including a polyamide, a mixture of acrylonitrile / butadiene / styrene and polyurethane, a polyether amide, an ethylene-propylene copolymer fluorinated, polypropylene, an ethylene-propylene copolymer, polyurethane, and a mixture of a polyamide and a polyether amide.

25. - An intravenous catheter assembly according to claim 18, further characterized in that the catheter is rigid at room temperature and flexible when exposed to moisture and body temperature.