Cannula having a wire that extends along said cannula

Abstract

A cannula has an electrically conductive material that runs along the cannula. This material has an electrical terminal, which can be wired or wirelessly connected with a measuring device. This makes it possible to acquire the position of the cannula in a human body, and generate a warning signal given a dislocation of the cannula.

Claims

1. A cannula with an electrically conductive material that runs along the cannula, wherein the material has an electrical terminal; wherein the cannula has an outer jacket and an inner jacket, which are electrically insulating, and between which the electrically conductive material is arranged such that the electrically conductive material is guided in a cannula wall and radially outwardly and radially inwardly insulated by a tubular wall; wherein the electrically conductive material extends in the cannula wall over an area along the cannula from the cannula tip to the electrical terminal; and wherein the cannula is adapted such that, when arranged in a body vessel, the outer jacket of the cannula acts as a dielectric, with the electrically conductive material corresponding to a first electrode, and the body vessel to a second electrode, such that the position of the cannula inside of a body part relative to an electrical contact surface can be measured.

2. The cannula according to claim 1, wherein the material is cylindrical in design along the cannula.

3. The cannula according to claim 1, wherein the material has a wire.

4. The cannula according to claim 3, wherein the wire is spirally wound.

5. The cannula according to claim 1, wherein the cannula has a transmitter that is connected with the electrical terminal.

6. The cannula according to claim 1, wherein the electrical terminal has a sliding contact.

7. The cannula according to claim 6, wherein the sliding contact is designed as an electrically conductive ring.

8. The cannula according to claim 7, wherein the electrically conductive ring is designed as a conical sleeve.

9. The cannula according to claim 1, wherein the cannula has an RFID element, which is connected with the electrical terminal in an electrically conductive manner.

10. The cannula according to claim 1, wherein the cannula has another electrical terminal that has no electrically conductive connection to the wire.

11. The cannula according to claim 1, wherein the cannula has a cable and a plug or a bushing, wherein there is an electrically conductive connection between the plug or the bushing and the cable, and between the cable and the electrical terminal.

12. A cannula system with the cannula according to claim 1, further comprising an electrical contact surface that can be fastened to a body surface and a measuring device that is electrically connected with the electrical contact surface and the terminal.

13. The cannula system according to claim 12, wherein the measuring device is a measuring device for determining the electrical capacitance.

14. The cannula system according to claim 12, wherein the electrical contact surface has a transmitter.

15. The cannula system according to claim 12, wherein the cannula system has a computer and a signaling device which are connected with the measuring device.

16. The cannula system according to claim 15, wherein the signaling device has several different signal transmitters.

Description

(1) An exemplary embodiment is shown on the drawing, and will be explained in more detail below. Shown on:

(2) FIG. 1 is a schematic section through a wire-reinforced cannula,

(3) FIG. 2 is a wire-reinforced cannula with electrical terminal,

(4) FIG. 3 is a top view of a wire-reinforced cannula,

(5) FIG. 4 is a schematic view of an electrical capacitor,

(6) FIG. 5 is a schematic view of a cannula system with cannula, electrical contact surface and measuring device,

(7) FIG. 6 is the cannula system shown on FIG. 5 with partially withdrawn cannula,

(8) FIG. 7 is the cannula system shown on FIG. 5 with completely withdrawn cannula,

(9) FIG. 8 is a cannula with electrically conductive material cylindrically formed along the cannula,

(10) FIG. 9 is a magnified view of the area of the cannula with electrical terminal shown on FIG. 8 with plug,

(11) FIG. 10 is an alternative embodiment of the cannula with electrical terminal shown on FIG. 8 with bushing,

(12) FIG. 11 is a plug-plug adapter,

(13) FIG. 12 is a magnified view of the areas of the electrical terminal,

(14) FIG. 13 is a cable with ring holder and bushing,

(15) FIG. 14 is the cable shown on FIG. 13 on the cannula,

(16) FIG. 15 is a magnified section through the area where the cable abuts against the cannula,

(17) FIG. 16 is the interaction between the cable shown on FIG. 13 and an electrically conductive ring as part of the cannula, and

(18) FIG. 17 is the interaction between the cable shown on FIG. 13 and a cannula according to FIG. 3 with a spiral wire.

(19) The cannula 1 shown on FIG. 1 has a polyurethane outer jacket 2 and a polyurethane inner jacket 3, which comprise an electrical insulation. A wire 4 extending spirally in the longitudinal direction of the cannula is arranged in between as the electrically conductive material.

(20) FIG. 2 shows how the wire 4 is laid around the polyurethane inner jacket 3 in tightly abutting windings visible from outside, and protected by the polyurethane outer jacket 2.

(21) FIG. 3 shows how the wire 4 at one end of the cannula 1 is guided through the polyurethane outer jacket 2 and to the outside, so as to form an electrical terminal 5 at which a cable 6 is used to tap an electrical potential that can be relayed to a measuring device 8 via the plug 7.

(22) If such a cannula 1 is arranged in a bodily vessel 9, the arrangement acts as an electrical capacitor or an electrical capacitance. FIG. 4 presents a schematic illustration of a capacitor that demonstrates how the polyurethane outer jacket 2 of the cannula 1 acts as a dielectric 10, with the reinforcing wire 4 corresponding to a first electrode 11, and the bodily vessel to a second electrode 12.

(23) These characteristics of a cannula arranged in a vessel are used in the cannula system 13 shown on FIGS. 5 to 7 to measure the position of a cannula 1 inside of a body part 16 relative to an electrical contact surface 14.

(24) To this end, for example, the electrical contact surface 14 is adhesively bonded to a skin area 15 in proximity to the vessel (not shown) with an EKG patch. The cannula is subsequently positioned in the body part 16, and in particular in a vessel, wherein the cannula 1 is pushed into the proximity of the contact surface 14. The cannula 1 is here connected with the electrical measuring device 8 via the electrical terminal 5 and the line 7, while the electrical contact surface 14 is connected with the measuring device 8 via a line 17.

(25) After the cannula 1 has been optimally positioned via the vessel access 18, the measuring device 8 indicates a value for the measured capacitance. In the exemplary embodiment, this value lies at 0.14 nF. This value is roughly proportional to the length 19 to which the cannula 1 is pushed into the body part 16.

(26) For example, if the cannula is now partially pulled out of the body part 16, and thus out of the vessel, by an awkward movement of the patient, the length 19 is reduced to a length 20, which also reduces the electrical capacitance indicated on the measuring device 8. In the present exemplary embodiment, the length 19 is reduced to roughly half its length 20, with the capacitance dropping from 0.14 nF to 0.07 nF in the process.

(27) FIG. 7 shows a case in which the cannula 1 has been completely pulled out of the body part 16. This causes the measured capacitance to drop to 0.00 nF.

(28) The measured value 21 determined with the measuring device 8 is transmitted to a computer 22, which compares the measured value with a prescribed measured value. Given a drop below a limit, the computer 22 activates a signaling device 23, for example which can emit an optical and/or acoustic signal. The signaling device can also be an alarm or monitoring system of a clinic. As a result, the medical personnel are informed that the position of the cannula should be checked.

(29) The computer 22 can also store the determined measured values over a period of time, so as to comprehensibly demonstrate how the cannula was moved relative to the body part 16.

(30) In addition, the computer 22 can also act on other devices, for example a pump connected with the cannula, for example to stop or reduce the inflow to the cannula when removing the cannula 1 from a vessel.

(31) FIG. 8 shows a cannula 30 with an electrically conductive material 31 cylindrically formed along the cannula and an RFID chip 32. This RFID chip 32 with its connection to the material 31 is incorporated insulated inside of the cannula, and the RFID chip is arranged on the cannula in such a way as to be located outside of the body when positioning the cannula in a body.

(32) FIG. 9 shows a cannula 40 with an electrical terminal 41, onto which a cable 42 is soldered. The cable 42 has a plug 43, which is used for connecting to the measuring device 8.

(33) FIG. 10 presents an alternative embodiment of the cannula 50. The cable 52 is here lengthened, and is connected with the electrically conductive material 53 via the electrical terminal 51. The end of the cable 52 has a bushing 54, which can also be used as a plug via the adaptor 55 depicted on FIG. 11.

(34) Such cannulas can be easily manufactured, so as to also be used as disposables.

(35) FIG. 12 shows a section of a cannula 50 consisting of a polyurethane material 56. Attached to the material 56 is a metal cannula reinforcement 57, which serves as a sensor element and is integrated into the cannula wall in such a way as to be electrically insulated to the outside and inside. An accessible metal electrically conductive area 58 in the cannula surface comprised of biocompatible material is electrically connected with the sensor element. The cable 52 is soldered onto this electrical terminal 51.

(36) Instead of soldering a cable 52 onto a contact 51, the embodiment variants shown on FIGS. 13 to 17 provide a cable 60 with a slip ring 61 and a bushing 62, which is designed as a reusable unit that can be disinfected and, in autoclaves, sterilized.

(37) This cable 60 can be easily secured via the slip ring 61 with an electrically conductive ring 63 having a conical sleeve 64. FIG. 15 shows how the ring 61 can be slipped onto the conical sleeve 64, so as to there enable an electrical contact between the electrically conductive material 65 and the cable 60 via the ring 61.

(38) FIG. 16 shows how the cable 60 is fastened to a ring 64 detached from the cannula. As an alternative, the ring 61 can also interact directly with a wire 71 spirally guided in a cannula 70 in an area 73 with insulation 72 removed.