HK1070849B - Catheter and use method thereof - Google Patents

Description

Catheter and method of use

Object of the Invention

The catheter and method of use thereof involves the use of a device consisting of three main parts including a cylinder with a cannula, a piston and a sleeve with a needle, which allows the use of the invention with only one hand, that is, which enables the needle and cannula to be introduced into the desired location (blood vessel, visceral space, etc.) in one operation with only one hand and ensures the hygiene of the operation without having air in contact with the internal device components, preventing the spread of infection or contaminants and introducing air into the blood vessel or living body.

This device and the method of use thereof have particular application in the medical and veterinary field, for the intravenous drainage of fluid products into living bodies, or preferably for the human body, as well as for the extraction of blood and any other body fluids, supplies of drugs, etc.

Background

There are a number of catheters and similar devices in the prior art for introducing a needle into a living body with minimal risk for this life and for supplying fluid components, mainly serum, into veins.

US-A-3827434 to VicrA Sterile inc discloses A catheter insertion device having A needle assembly comprising A hollow slotted needle having its shaft fixed to its proximal end. The catheter assembly includes a flexible catheter having a sealing segment with an enlarged outer diameter to prevent backflow of blood, and a hollow catheter shaft secured to a proximal end thereof. All components are releasably locked together to prevent relative longitudinal movement of the catheter in the needle, which can be released in the absence of relative longitudinal movement between the catheter and the needle. The catheter has a stylet with an enlarged rounded tip.

US patent 4950252 by Luther Medical Products inc. discloses a needle, cannula and a device for protecting the needle by a tube within which the needle slides. The tube is held by one hand only, with the cannula fixed thereto, and the needle sliding inside it, which is also connected to the tube. The needle and cannula are introduced into the living body with only one hand and it is not possible to find out whether they are both introduced into the vein or, conversely, whether a second needle is required to introduce the composition into the vein. Once introduced into the living body without ensuring correct introduction into the vein, the needle is withdrawn from the cannula and out of the body, while the flap at the upper part of the tube connected to the needle slides backwards. After withdrawal of the needle, and if the cannula is correctly introduced, the cannula is detached from the tubular body, and an infusion set, which is subsequently connected to a container with the liquid to be supplied, is connected to the free end of the cannula.

Similar to any commercially available device, the main problem with this device is that it requires contact with the outside, air, which can result in dangerous ingress of air into the vein or contamination of the blood stream from air contact when the cannula is connected to the infusion set. Another disadvantage that results is that, at the same time as the puncture, i.e. when inserting the needle and the cannula, it is not possible to judge whether the cannula is in the desired position, through which it may have passed, which will result in a new puncture being performed.

Another device similar to the one described above is also disclosed in us patent 5456668 filed by f.h. faulting & co.limited and includes a system in which the needle is hidden inside a tube after being introduced into a living body together with a cannula. This device has the same disadvantages as the device described above.

Another novel feature of the device of the present invention is that the needle is used to introduce a cannula into the vein, and the cannula can then be withdrawn. Prior to the needle disclosed in this patent specification, a needle is disclosed in us patent 4354491 to Steven l. The structure of the needle prevents the cannula from being removed from its position inside the needle until the user wishes to do so, but by means of the structure of the invention the same function is achieved with a simpler and more advantageous design and characteristics.

With respect to the use flow used now, it basically comprises: a hollow needle is introduced into the plastic cannula and is provided with a transparent or translucent tube at its opposite end, similar to a coating. Once the needle with the cannula has been introduced into the desired position, it is checked whether it has been correctly introduced into said position. This test is performed by observing whether the rear transparent or translucent tube of the catheter has been filled with blood, and if so, the cannula is slid into the interior of the needle at the puncture area, and then the needle is withdrawn and the cannula is left in vivo to then connect the distal end of the cannula to the infusion set. The infusion set is connected to a container having a liquid component.

Such a device has the previously disclosed disadvantage that the needle tip is not correctly positioned in the living body, since even if the rear catheter body contains blood or fluid, this does not imply a permanent retention of the needle tip in the desired position of the living body. When this occurs, the plastic cannula does not slip into the interior of the living body due to its repetition and the corresponding failure of its movement, causing bleeding, hematoma, vein rupture, infection, etc.

Another drawback of the above device is that, in the case of a cannula correctly introduced into the living body, when the needle is withdrawn and the blood at the rear of the plastic cannula and inside it comes into contact with external contaminants, air, there is the possibility of insanitation and contamination, and of concurrent infection and air ingress (which may lead to air embolism).

Disclosure of Invention

The invention comprises the following steps: connecting the three separate parts or bodies forming the catheter for introducing the cannula to the desired location (blood vessel, visceral space, etc.); ensuring that it is properly set for the next supply of fluid composition or withdrawal of fluid therefrom.

The individual components or bodies are: a cylinder having a cannula to be introduced into a patient connected thereto; a piston that slides along the length of the cylinder and is then connected to the plastic tube using a connector for an infusion set; and a cylindrical sleeve to which the needle is connected, the cylinder sliding linearly on the sleeve. The cylinder is introduced into the tube and will slide along its length by means of a guide groove provided on the outside of the cylinder, which is assembled on a guide rail on the inside of the tube, the piston being located inside the cylinder and being able to have, at its end, a plastic tube which is connected to the infusion set and then to the supply container. The cannula, connected to the cylinder, is arranged inside the needle, the needle being horizontally sectioned along its diameter except at the front, where the wall can be higher than the horizontal section to resemble a curved protrusion, the curved surface being continuous.

After assembling the three components forming the catheter, the catheter may be adapted for single-handed use, with the thumb on one side and the index finger on top, on a stop connected to the plunger, and the other fingers holding the side opposite the thumb. It is possible to purge all components connected to the contained fluid prior to use of the conduit. To use the catheter, a needle-cannula assembly is introduced into the desired area and it is verified whether the cannula and needle are indeed introduced into the living body, the assembly being slightly withdrawn by pushing the piston when the index finger acts on the stop, so that if the assembly is in the desired position, the cylinder will be filled with blood and liquid from the living body. Once we have determined with the "set check in the vein" system that it is in place, there is no need to repeat the puncture and continue to cause pain to the patient and damage the punctured living body, while the flap is pushed with the same index finger, causing a corresponding slippage of the cannula in the body. Once the cannula has been introduced into the living body, the sleeve with the needle is removed from its interior as a result of the slotted opening of the sleeve allowing the cannula and the needle to be separated, while only the cannula remains in the vein, while the cylinder and the piston are supported on the outside of the patient's arm.

By opening the valve switches at the end of the supply container and the piston, the necessary fluid components are supplied to the patient without the risk of air entering therein and without the risk of infection by contact with air, since the system has been purged from the beginning of the operation.

Drawings

For the purpose of facilitating an understanding of the invention, there are attached 19 figures, the purpose of which is to provide a better understanding of the principles underlying the invention and to better illustrate the forms of the preferred embodiments of the invention, it being noted that these figures are by way of illustration and not of limitation.

Figure 1 shows two possible forms of the free end of the needle and an exploded perspective view of the catheter components.

Figure 2 shows a perspective view of the catheter before assembly of its two parts.

Figure 3 shows a perspective view of the catheter ready for use and details of the needle.

Figure 4 shows a cross-sectional view of the catheter as it is introduced into the patient and an enlarged detail of the introduction of the needle/cannula into the vein.

Figure 5 shows a cross-sectional view of a catheter with a cannula and needle introduced into a vein and blood drawn.

Fig. 6 shows a cross-sectional view of a catheter with a cannula introduced into a vein.

Figure 7 shows a cross-sectional view of the catheter with the needle introduced into the vein and the cannula withdrawn.

Figure 8 shows a cross-sectional view of the catheter with the needle retracted and the cannula fully introduced into the vein.

Fig. 9 shows a cross section taken along the plane a-B in fig. 3.

Fig. 10 shows an enlarged view of a needle with a cannula.

Fig. 11 shows a front view of the components of fig. 10.

Fig. 12 shows a top view of a needle with a cannula.

Fig. 13 shows a cross-section taken along the plane C-D in fig. 10.

Fig. 14 shows a section along the plane E-F in fig. 10.

Fig. 15 shows an exploded perspective view of a second preferred form of conduit.

Figure 16 shows a perspective view of the second preferred form of conduit prior to assembly of its two parts.

Figure 17 shows a perspective view of a second preferred catheter form to be used and details of the needle.

Fig. 18 shows another preferred catheter form, in which the needle is introduced inside the cannula.

Figure 19 shows a cross-sectional view of a catheter with a needle introduced into the cannula.

Detailed Description

In fig. 1, it can be seen that all components of the catheter of the present invention are in a pre-assembled state. Prior to assembly of the catheter, it has three separate bodies: a cylinder 10 having an insertion tube 30 to be introduced into a patient, the insertion tube being connected to the cylinder 10; a piston 20 introduced into the cylinder 10, forming a hermetically sealed chamber with a rubber 22 at the end of the piston 20, and sliding along the length of the cylinder 10; and a cylindrical sleeve 40 to which the needle 50 is connected, on which the cylinder 10 and the cannula 30 slide linearly.

Next, the hollow cylinder 10, which is hollow and open at its rear end, has three different sections from its front inclined end 12, where the insertion tube 30 is connected to the cylinder 10, also the interior of the hollow insertion tube 30 is connected to the hollow interior of the cylinder 10. The cylinder has guide rails 11 on both sides thereof, on which guide grooves 41 provided on the inside of the sleeve 40 slide. The front end of the cannula 30 opposite to the point of connection with the cylinder 10 has two intersecting planes which form the shape of its free end, the upper part 31 of the cannula being inclined in one direction and the lower part 32 being inclined in the other direction so as to conform to the inclination of the needle 50 without exceeding the needle.

The piston 20, which is introduced into the cylinder 10 and slides in the cylinder 10, is pierced in the form of a hole 23 passing through it, while its front end has a rubber stopper 22, which is also hollow. There is an empty or hollow space between the main cylindrical portion 26 of the piston 20 and the pusher 27, which is connected to the piston at its rear end and which allows the piston 20 to slide along the length of the cylinder 10 with the aid of a flap 21 arranged at the front end of the pusher 27 and perpendicular to the pusher 27, to enable the cylinder 10 to be introduced, thus keeping the piston 20 accommodated in the cylinder 10. At the rear, the piston 20 has a flexible conduit 24 for introducing fluid into the patient. This can be connected to an infusion set or another fluid, such as serum, connected to a container containing the fluid component via a connector 25 at the end of the catheter 24.

The third body part, the sleeve 40, has, in addition to the guide grooves 41 for receiving the guide rails 11 of the cylinder 10, cylindrical openings in its upper part, as well as in the front and rear part, and flanges or projections 42 in its rear part to prevent the piston 20 from falling out of the cylinder 10, in particular slipping backwards, in one duct-operating movement. The front side of the sleeve 40 has a needle 50 attached to it, which is cut in half over most of its length, which has two possible configurations: the first configuration has a protrusion 51 at its end near the end of the needle 50, almost changing the semi-circular cross-section of the needle 50 into a circle, and has a bevel 52 towards the front of the needle, which then has a horizontal span 54 ending in a tip 53 with an inclination; in the second configuration, the angled portion 56 of the projection 55 conforms to the tip 56 or free end of the needle 50.

The catheter assembly is very simple and consists of the following steps: the piston 20 is introduced into the cylinder 10, and then the guide rail 11 of the outer cylinder 10 is fitted into the guide groove 41 of the inner side of the sleeve 40. After the cylinder 10 has been introduced into the sleeve 40, it can be seen how the cannula 30 connected to the cylinder 10 is held in the space defined by the needle 50 and the projection 51 of the needle 50, the inclination of the upper part 31 of the cannula 30 corresponding to the inclination of the free end of the needle 53. The protrusion 51 thus ensures that the cannula does not slip perpendicular to the needle 50.

The method of use of the catheter is suitable for one-handed use without risk of contamination, infection or air ingress, and it has been provided for this purpose. In the desired situation it is possible to first purify all material, for which purpose a serum bottle is connected to the infusion set and the connector 25, after which the infusion set valve switch is opened, thereby purifying all material. To grip the catheter, a thumb 71 is placed on one side of the sleeve 40, a forefinger 72 is supported at the rear of the flap 21 and on the slider 27, and the remaining fingers are on the opposite side of the thumb to assist in gripping the sleeve 40. Once the device is secured, the device is tilted for the purpose of introducing the cannula 30 supported on the needle 50 into the patient. This begins with the introduction of the tip of the needle 50, which has the same inclination as the upper part of the cannula 31, so that the two inclined parts coincide in the span 33 to facilitate its introduction into the patient. After the needle 50 and cannula 30 are introduced so that they pass through the skin and subcutaneous tissue 61, they reach the vein wall 62 where the cannula 30 must be introduced. To do so, it is passed through the vein wall 62 by gently introducing the tip 53 of the needle and the leading end 31 of the cannula into the vein 63. Once the leading end is introduced into the vein 63, it is necessary to check whether the cannula 30 is inside the vein 63, since it may happen that the cannula 30 is introduced outside the vein 63 by mistake, passing it completely through the vein.

To perform the test, once the component is in the position shown above, the index finger 72 is supported in front of the flap 21, rather than at its rear, and the finger 72 is removed, so that the slide 27 slides backwards, which achieves a corresponding suction of blood from inside the vein 63, the blood flowing through the cannula 30 flowing into the cavity 13 of the cylinder 10 formed by the front inclined portion 12 of the cylinder. Due to the translucent nature of the material of which the cylinder and the piston are made, the user is able to verify that the chamber 13 is filled with blood and verify that the needle 50 and the free end of the cannula 30 are located within the vein 63, that is, in the correct position for the cannula 30 to be fully inserted.

To continue introducing the cannula 30, the position of the index finger 72 is changed again, the index finger being supported again on the rear part of the flap 21 and on the slide 27 and, when the flap 21 is pushed forward (towards the vein 63), it slides the cannula 30 relative to the needle 50 in the direction of the vein 63, and the entire "cylinder-piston" assembly 10-20 relative to the sleeve 40 in the guide groove 41 and in the guide rail 11 in the direction of the vein 63.

Once the cannula 30 is introduced into the interior of the vein 63, the needle 50 is retracted from the interior of the vein 63, for which purpose the sleeve 40 is pulled back, but carefully to ensure that the cannula 30 remains within the vein 63. The needle 50, which has a curved protrusion 51 at its front end to prevent the cannula 30 from turning, releases the cannula 30 by a slight deformation of the cannula 30, which is made of a flexible material and protrudes from the groove between the two protruding curved walls 51 of the needle 50.

Once the cannula 30 is introduced into the vein 63 and the "cylinder-piston" 10-20 assembly is secured to the patient, a valve switch (not shown) provided on the infusion set connected to the connector 24 is opened to allow liquid, such as serum, from the bag to be introduced into the patient. To prevent the patient from operating the piston while it is fixed to his living body, it is possible to separate the flap 21 from the slide 27 by slight manual pressure.

A variation on the above arrangement includes providing a longer piston, using a connection point 25 directly coupled to its end, rather than through the conduit 24. The arrangement of the remaining components is the same as the detailed assembly described above.

In order to use the needle 87 and cannula 89 of the catheter now in use so that it is not necessary to manufacture parts with a special design, another variation of the above example involves the use of a needle 87 that is introduced into the cannula 89. This function is similar to that described above, but differs from the devices currently in use in that it is not necessary to draw in order to verify that the cannula is in place, in which device it is possible to draw in fluid and blood with the piston to verify or verify that the cannula 89 is properly positioned in the vein 63.

For this purpose, the device has a cylindrical body 80, which has, in its upper part, a plurality of guide slots 85 for receiving the body of the pusher, which pusher is formed by a component having, on its side 84, guide rails and flaps 83. Within the cylindrical member 80 there is a piston 91, formed at its rear by a wall 81 on which the slide 84 is supported. The cylindrical member 80 has a flange 82 on its rear portion for preventing the piston 91 from coming out of the cylinder 80. The rear part of the cylinder 80 has a needle 87 which is connected to the cylinder by means of a conical part 86, the cannula being fixed to the cylindrical part 80 due to the introduction of the conical part 88 of the cannula 89 on the conical part of the cylinder 80.

This function differs from the previous one in that once the cannula 89 and the needle 87 have been introduced inside the vein and after checking their correct position by pushing the flap 83 to draw blood, it is necessary to then completely extract the needle and the cylinder member, which forces the cannula through its conical member 88 open to the outside environment, with the risk of contamination of the patient. To reduce this risk, it is necessary to connect the catheter to the end of the cannula 90 as soon as possible in order to introduce the serum, for example, into the patient.

The invention is capable of other embodiments and of being practiced and carried out in other than the described exemplary embodiments, which differ only in detail. The invention may thus be implemented in any shape and size, using the most suitable means and materials, and using the most convenient components, possibly substituted by other technically equivalent elements, which are all encompassed by the claims.

Claims (9)

1. Catheter with a sleeve (40) with a needle (50) and a cylinder (10) with a cannula (30), characterized in that it comprises three independently assembled bodies:

a hollow cylinder (10) having an opening at the rear end thereof and having an insertion tube (30) and a guide (11) connected to the front end thereof;

a hollow piston (20) perforated along its entire length, having a flap (21) and a pusher (27) in its upper part, and having a plastic tube (24) at its rear end, which has a joint (25); and

a sleeve (40) having a guide (41) and open at its upper, front and rear ends, the front end of which has a needle (50) attached thereto, the needle having a semicircular cross-section over most of its length,

thus, for assembling the self-contained assembly body, the piston (20) is introduced inside the cylinder (10), the guide means (11) of the cylinder (10) and the guide means (41) of the sleeve (40) cooperate to assemble the cylinder (10) to the sleeve (40) and to introduce the cannula (30) into the needle (50), and the front portion of the piston (20) has a rubber stopper (22) with a hole (23) which provides a hermetic sealing condition for the cylinder (10).

2. A catheter as claimed in claim 1, characterized in that the flap (21) of the piston (20) is connected to the front end of the pusher (27) and is perpendicular to the pusher (27), the rear part of said pusher (27) being connected to the rear end of the piston (20), leaving a cavity or space between the curved upper surface of the piston (20) and the underside of the pusher (27) to enable the wall of the cylinder (10) to be introduced into said cavity, whereby the piston (20) is accommodated in the cylinder (10), and the pusher (27) and the flap (21) are arranged outside the cylinder (10).

3. Catheter according to claim 1, characterized in that the flap (21) can be retracted from the pusher (27) by slight manual pressure.

4. A guide tube according to claim 1, characterized in that the guide means (11) of the cylinder (10) are constituted by guide rails (11) and the guide means (41) of the sleeve (40) are constituted by guide grooves (41).

5. Catheter according to claim 1, characterized in that the sleeve (40) has a flange or projection (42) at its open rear end, which limits the backward sliding of the piston (20).

6. Catheter according to claim 1, characterized in that the joint (25) is provided at the end of a plastic tube (24), said plastic tube (24) being a continuation of the bore of the piston (20).

7. Catheter according to claim 1, characterized in that the needle (50) has in its front a span where the needle section is not semicircular, a protrusion (51) rising to almost complete the circular section of the needle and having a rising and falling bevel (52) constituting the section from the semicircular section of the needle (50) to the almost circular section of the needle (50), and after the falling bevel (52) a horizontal span (54) ending at the free end of the needle (50).

8. Catheter according to claim 1, characterized in that the needle (50) has a span at its front where the needle section is not semicircular, at its free end a projection (55) rising to almost complete the circular section, the needle having a rising and falling bevel (56) constituting the ascending and descending bevel from the semicircular section of the needle to the almost circular section of the needle, the inclination of the descending bevel (56) coinciding with the inclination of the free end of the needle (50).

9. Catheter according to claim 1, characterized in that the free end of the cannula (30) has sections (31, 32) which form the shape of its free end, the upper part (31) of which has the same inclination as the free end of the needle (50), while the lower part (32) is inclined in the other direction, preventing the cannula (30) from protruding beyond the needle (50).