Electric- or Magnetic-Field Based Detection of when Electrode Pads have been Handled or Removed from their Package

• US 20080140171A1
• Filed: 06/01/2004
• Published: 06/12/2008
• Est. Priority Date: 06/27/2003
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Hansen, Kim, Roberts, Douglas
• Granted Patent: US 8,463,405 B2
• Time in Patent Office: Days
• US Class Current: 607/142
• CPC Class Codes: A61N 1/0408 Use-related aspects
• CPC Class Codes: A61N 1/046 Specially adapted for shock therapy, e.g. defibrillation
• CPC Class Codes: A61N 1/0492 Patch electrodes A61N1/0412, A61N1/0428 take precedence
• CPC Class Codes: A61N 1/3931 Protecting, e.g. back-up systems
• CPC Class Codes: A61N 2001/37294 Means for testing medical devices within the package prior to implantation

Abstract

Handling or removal of a pair of defibrillator electrode pads from their package is detected in order to effectively time the issuance of prompts to guide the user. One plate of a capacitor is embedded in the package, the electrode pads and lead wires serving as the other plate. Impedance across the capacitor in an alternating current circuit is monitored to detect an increase in the distance between the pads and the package. The impedance level is determined, in a low-cost hardware solution, by rectifying and then integrating an output voltage of the capacitor to produce a voltage signal whose magnitude attenuates as the pads arc handled or removed. In one embodiment, the above methodology is time-division multiplexed with an alternative process that identifies handling or removal based on pad-to-pad impedance. In a further embodiment, the capacitive configuration is replaced with an inductive one.

Claims

1. An apparatus comprising:

an electrode with attached lead wire;

a conductor;

a source of alternating current; and

an electrode deployment detector configured for;

monitoring a magnitude of an electrical characteristic measured from an electrical circuit having from said source an alternating electric current path that includes said electrode with attached lead wire, said conductor, and a space or other electrical insulator intervening between said conductor and said electrode with attached lead wire, said conductor being disposed in proximity of said electrode with attached lead wire to create capacitance in said electrical circuit; and

identifying, based on said magnitude, an occurrence of at least one of handling of said electrode with attached lead wire and removing of said electrode with attached lead wire from a package containing said electrode with attached lead wire.

3. The apparatus of claim 1, wherein said electrical circuit includes an integrator in series with said capacitance.

4. The apparatus of claim 3, wherein said electrical circuit further includes a rectifier for rectifying input voltage to the integrator.

5. The apparatus of claim 1, wherein said source periodically shifts between different frequencies of alteration.

6. The apparatus of claim 5, wherein said electrical circuit is configured so that said magnitude varies with said capacitance;

and wherein said detector is configured to perform said identifying based on at least one of a sum and a difference between measurements of said magnitude that correspond to respective ones of said frequencies.

7. The apparatus of claim 1, wherein the alternating electric current path further includes another electrode and attached lead wire.

8. The apparatus of claim 7, wherein the alternating electric current path further comprises an electrically conductive medium disposed between the electrodes that provides a pathway for flow of electric current from one of the lead wires to the other by means of the electrodes and said medium.

9. The apparatus of claim 8, wherein activation of a source for the electric current from one of the lead wires to the other and activation of said source of alternating current are alternated in a time division manner.

10. The apparatus of claim 1, comprising a defibrillator that is configured to issue a sequence of user prompts and to advance from a particular one of the user prompts to a next one of the user prompts upon said identifying.

17. The method of claim 1, wherein the alternating current path further includes another electrode and attached lead wire.

18. The method of claim 17, wherein the alternating current path further comprises an electrically conductive medium disposed between the electrodes that provides a pathway for flow of electric current from one of the lead wires to the other by means of the electrodes and said medium.

19. The method of claim 8, wherein activation of a source for the electric current from one of the lead wires to the other and activation of said source of alternating current are alternated in a time division manner.

2. The apparatus of claim l, wherein said electrical circuit is configured so that said magnitude varies with said capacitance.

11. A method comprising the steps of:

monitoring a magnitude of an electrical characteristic measured from an electrical circuit having from an alternating current source an alternating electric current path that includes an electrode with attached lead wire, a conductor, and a space or other electrical insulator intervening between said conductor and said electrode with attached lead wire, said conductor being disposed in proximity of said electrode with attached lead wire to create capacitance in said electrical circuit; and

identifying, based on said magnitude, an occurrence of at least one of handling of said electrode with attached lead wire and removing said electrode with attached lead wire from a package containing said electrode with attached lead wire.

12. The method of claim 11, wherein said electrical circuit is configured so that said magnitude varies with said capacitance.

13. The apparatus of claim 11, wherein said electrical circuit includes an integrator in series with said capacitance.

14. The apparatus of claim 13, wherein said electrical circuit further includes a rectifier for rectifying input voltage to the integrator.

15. The method of claim 11, wherein said source periodically shifts between different frequencies of alternation.

16. The method of claim 15, wherein said electrical circuit is configured so that said magnitude varies with said capacitance, and wherein the identifying step performs said identifying based on at least one of a sum and a difference between measurements of said magnitude that correspond to respective ones of said frequencies.

20. The method of claim 11, further comprising the step of issuing a sequence of user prompts, the issuing step including the step of advancing from a particular one of the user prompts to a next one of the user prompts upon said identifying.

21. An apparatus comprising:

an alternating current (AC) source;

an AC circuit powered by said source and having a complex-impedance-generating element with at least one electrode pad that is within said circuit, said element being expandable from a package containing said element to change a voltage drop across said element; and

an electrode deployment detector configured for monitoring a magnitude of an electrical characteristic measured from said circuit to identify based on said magnitude, an occurrence of at least one of handling of said element and removing of said element from said package.