DEVICE AND METHOD TO POSITION A CANNULA FOR NERVE BLOCK

• US 20090210029A1
• Filed: 02/11/2009
• Published: 08/20/2009
• Est. Priority Date: 02/14/2008
• Status: Abandoned Application

• Current Assignee: Pajunk GmbH & Co. KG Besitzverwaltung
• Original Assignee: Pajunk GmbH & Co. KG Besitzverwaltung
• Inventors: TSUI, Ban C.H.
• Application Number:
  US12/369,044
• Publication Number:
  US 20090210029A1
• Time in Patent Office: Days
• US Class Current: 607/46
• CPC Class Codes: A61B 17/3401 Puncturing needles for the peridural or subarachnoid space or the plexus, e.g. for anaesthesia local anaesthesia A61M19/00
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/415 the glands, e.g. tonsils, adenoids or thymus
• CPC Class Codes: A61B 5/4821 Determining level or depth of anaesthesia A61B5/1106 takes precedence
• CPC Class Codes: A61B 5/489 Blood vessels
• CPC Class Codes: A61B 5/4893 Nerves
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: A61B 5/7405 using sound

Abstract

A device and method to position a cannula or a catheter for nerve block are provided for use with a unipolar cannula (10), which is electrically insulated around its axial length. The device includes a stimulation device (20) to generate an electrical signal, an electrically conductive bare stimulation electrode (12) provided on a distal end of the unipolar cannula (10) and a skin electrode (14), which can be applied to a body surface (26) of a patient with an electrically conductive contact. The stimulation electrode (12) and the skin electrode (14) can be connected to the stimulation device (20), so that the electrical signals are routed from the stimulation electrode (12) through a patient'"'"'s body (28) to the skin electrode (14). Further, the stimulation device (20) includes a measuring device (22) to measure the electrical resistance between the stimulation electrode (12) and the skin electrode (14) and the stimulation device (20) includes an alarm device (24) which produces an audible alarm signal when the measured resistance exceeds an adjustable threshold value.

Claims

1. A device to position a cannula or a catheter for nerve block for use with a unipolar cannula (10), which is electrically insulated around its axial length, the device comprising:

a stimulation device (20) to generate an electrical signal;

an electrically conductive bare stimulation electrode (12) provided on a distal end of the unipolar cannula (10);

a skin electrode (14), which can be applied to a body surface (26) of a patient with an electrically conductive contact;

wherein the stimulation electrode (12) and the skin electrode (14) can be connected to the stimulation device (20), so that the electrical signals are routed from the stimulation electrode (12) through a patient'"'"'s body (28) to the skin electrode (14);

wherein the stimulation device (20) comprises a measuring device (22) to measure the electrical resistance between the stimulation electrode (12) and the skin electrode (14), and

wherein the stimulation device (20) comprises an alarm device (24) which produces an audible alarm signal when the measured resistance exceeds an adjustable threshold value.

2. The device according to claim 1, wherein the alarm device (24) is designed to produce an acoustic signal.

3. The device according to claim 1, wherein a catheter can be introduced through the cannula (10).

4. The device according to claim 3, wherein a stimulation electrode is arranged on the distal end of the catheter to which the stimulation device (20) is connected.

5. The device according to claim 1, wherein the electrical signals are electric pulses.

6. The device according to claim 5, wherein the electric pulses are adjustable as to amplitude and/or length and/or frequency.

7. A method to position a cannula or a catheter for nerve block, comprising the following steps:

providing of a stimulation device which generates electrical signals;

providing a cannula which is electrically insulated along its axial length and is provided with a bare electrically conductive stimulation electrode on its distal end;

applying a skin electrode to the body surface of a patient in a fashion that the skin electrode is in electrically conductive contact with the body surface;

connecting the cannula and the skin electrode in electrical conductance to the stimulation device in a fashion that the electrical signals of the stimulation device are applied to the stimulation electrode of the cannula and the skin electrode;

penetrating the patient'"'"'s body with the cannula;

measuring of the cannula in the patient'"'"'s body between the stimulation electrode and the skin electrode when the cannula penetrates;

localizing the position of the distal end of the cannula with the stimulation electrode with respect to a nerve to be blocked based on the increase of the resistance when the stimulation electrode penetrates the nerve sheath of the nerve.

8. The method according to claim 7, wherein an alarm signal is produced when the measured resistance exceeds a threshold value.

9. The method according to claim 8, wherein the threshold value is adjustable.

10. The method according to claim 7, wherein the electrical signals are current pulses.

11. The method according to claim 10, wherein the current pulses are adjustable in terms of amplitude and/or length and/or frequency.

12. The method according to claim 7, wherein a catheter is introduced through the cannula when the distal end of the cannula is positioned on the nerve.

13. The method according to claim 12, wherein a stimulation electrode is provided on the distal end of the catheter and wherein the stimulation electrode of the catheter is connected to the stimulation device.

14. The method according to claim 7, wherein when piercing and positioning the cannula, this cannula injects a physiological fluid with low electrical conductivity.

15. The method according to claim 14, wherein the physiological fluid is D5W (5% dextrose in water).

16. The method according to claim 14, wherein the position of the point of the cannula can be localized by the increase and time of the measured resistance after injection of the fluid.

17. The method according to claim 8, wherein the alarm signal is an optical and/or preferably acoustic alarm signal