Medical electrode with reusable conductor and method of manufacture

• US 4,827,939 A
• Filed: 03/14/1988
• Issued: 05/09/1989
• Est. Priority Date: 07/18/1985
• Status: Expired due to Term

• Current Assignee: NDM, Inc.
• Original Assignee: Baxter International Inc.
• Inventors: Cartmell, James V., Burcham, Larry R., Wolf, Michael L.
• Primary Examiner(s): Coven, Edward M.
• Assistant Examiner(s): Citrin, Randy
• Application Number:
  US07/170,129
• Time in Patent Office: 421 Days
• Field of Search: 128/639, 128/640, 128/641, 128/783, 128/798, 439/680, 439/681, 439/441
• US Class Current: 600/392
• CPC Class Codes: A61B 2562/0215 Silver or silver chloride containing
• CPC Class Codes: A61B 2562/0217 Electrolyte containing
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 5/259 using conductive adhesive means, e.g. gels

Abstract

A medical electrode intended for short term use has a disposable electrode pad provided with a socket and a reusable electrode conductor which is attached to a lead wire and which has a ridged body adapted to enter and be retained by the socket. The pad includes a pair of spaced foam sheets with patient-contacting adhesive layers on their lower surfaces. An electrolyte gel matrix, preferably formed from conductive adhesive urethane hydrogel, is located between the foam sheets. The socket is formed in a relatively stiff socket plate that overlies the gel matrix and the foam sheets. The socket includes a bore located over the gel matrix shaped to receive the electrode conductor, which is slightly larger than the bore, and may optionally include outwardly extending slits projecting from the bore. A method of manufacturing a strip of the electrode pads on a release liner on a continuous basis is disclosed. In a modification for longer term monitoring uses, the electrode pads are constructed to confine the gel matrix to avoid gel dry out and the socket and the conductor are provided with a cooperating key and keyway for restraining relative movements therebetween.

Claims

1. A disposable medical electrode pad of the type adapted to be removed from a release liner and applied to the skin of a patient for use with a reusable electrode conductor comprising a pair of mutually-spaced foam sheets having mutually substantially coplanar respective upper and lower surfaces, a patient-contacting adhesive on said lower surfaces, and a gap between mutually confronting edges of said sheets, an electrolyte gel matrix filling said gap, a socket plate overlying said gel matrix and overlapping said foam sheets, a said socket plate comprising a sheet of plastic and socket means overlying said gel matrix for removably assembling an electrode conductor in engagement with said gel matrix, and means adhering said socket plate to said foam sheets.

2. The pad of claim 1, wherein said electrolyte gel matrix comprises a hydrogel.

3. The pad of claim 1, wherein said electrolyte gel matrix comprises a urethane hydrogel.

4. For use with a reusable electrode conductor, the combination of a release liner and a disposable medical electrode pad comprising a pair of mutually-spaced foam sheets on said release liner, said pair of foam sheets having mutually confronting edges with a gap therebetween, an electrolyte gel matrix on said release liner filling said gap between said foam sheets, a socket plate overlying said gel matrix and overlapping said foam sheets, said socket plate comprising a sheet of plastic having a socket therein overlying said gel matrix for receiving an electrode conductor, said socket comprising a bore extending through said socket plate, and means adhering said socket plate to said foam sheets.

5. The combination of claim 4 wherein each of the sheets of said pair of foam sheets has a patient-contacting adhesive on its surface engaged with said release liner.

6. The combination of claim 4 wherein said release liner has a trough bounded by mutually-spaced surface portions on which each of the sheets of said pair of foam sheets are respectively located and said gel matrix fills said trough and the area between said foam sheets.

7. The combination of claim 6 wherein each of said foam sheets has a patient-contacting adhesive on its surface engaged with said release liner.

8. The combination of claim 4 wherein said electrolyte gel matrix comprises a hydrogel.

9. The combination of claim 4 wherein said electrolyte gel matrix comprises a urethane hydrogel.

10. For use with a reusable electrode conductor, a disposable medical electrode pad comprising a socket plate comprising a substantially flat sheet of relatively stiff plastic having first and second oppositely facing sides and socket means for receiving an electrode conductor, a pair of mutually-spaced foam sheets overlapped by said socket plate and extending from said first side to said second side of said socket plate, an electrolyte gel matrix between said foam sheets and underlying said socket plate and said socket, and means adhering said socket plate to one surface of each of said foam sheets, said foam sheets and said gel matrix each having exposed first edges extending below said socket plate on said first side of said of socket plate and exposed second edges extending below said socket plate on said second side of said socket plate, and each of said foam sheets having a patient-contacting adhesive on its surface opposite said one surface thereof adhered to said socket plate.

11. The pad of claim 10 wherein said electrolyte gel matrix comprises a hydrogel.

12. The pad of claim 10 wherein said electrolyte gel matrix comprises a urethane hydrogel.

13. The electrode of claim 10 wherein gel matrix is thicker than said foam sheets.

14. The pad of claim 13 wherein said electrolyte gel matrix comprises a hydrogel.

15. The pad of claim 13 wherein said electrolyte gel matrix comprises a urethane hydrogel.

16. For use with a reusable electrode conductor, an electrode assembly comprising a disposable medical electrode pad comprising an electrolyte gel matrix and a socket plate overlying said gel matrix, said socket plate comprising a sheet of plastic having a socket therein overlying said gel matrix for receiving an electrode conductor, said socket comprising a bore extending through said socket plate and a plurality of slits extending outwardly from said bore so that said socket plate has flaps adjacent said bore, each bounded by a pair of said slits, said flaps defining means aiding in the retention of said electrode conductor.

17. The electrode assembly of claim 16 further comprising a release liner, a pair of mutually-spaced foam sheets on said release liner, said gel matrix being on said release liner between said foam sheets, and means adhering said socket plate to said foam sheets.

18. The electrode assembly of claim 17 wherein said foam sheets have a patient-contacting adhesive on their surfaces engaged with said release liner.

19. The electrode assembly of claim 17 wherein said release liner has a trough bounded by surface portions on which said foam sheets are located and said gel matrix fills said trough and the area between said foam sheets.

20. The electrode assembly of claim 16 further comprising a release liner, a foam body having an adhesive coating on its bottom surface engaging said release liner, said foam body having a bore extending therethrough, and said gel matrix being positioned on said release liner and within said last mentioned bore.

21. The electrode assembly of claim 16 wherein said socket further includes a keyway adapted to interfit with a reusable electrode conductor having a key adapted to fit within said keyway to restrain relative movement between said pad and said conductor.

22. For use with reusable electrode conductors, a strip assembly comprising:

a release liner comprising an elongate strip of sheet material formed with a central, longitudinally-extending trough bounded by mutually-spaced, upwardly-facing surface portions of said liner; and

a plurality of disposable medical electrode pads aligned in side-by-side relationship on said release liner, each of said pads comprising;

a pair of mutually-spaced foam sheets each located respectively on one of said upwardly facing surface portions of said release liner, an electrolyte gel matrix filling the entire length of said trough bounded by said foam sheets and the area between said foam sheets, and a socket plate adhered to said foam sheets and overlying said gel matrix, said socket plate comprising a sheet of plastic having a socket therein overlying said gel matrix for receiving an electrode conductor, said socket comprising a bore extending through said socket plate.

23. The strip assembly of claim 22 wherein said foam sheets have a patient-contacting adhesive on their surfaces engaged with said release liner.

24. The strip assembly of claim 22 wherein said socket of each of said pads further comprises a plurality of slits extending outwardly from said bore so that said socket plate has flaps adjacent said bore, each bounded by a pair of said slits, said flaps defining means aiding in the retention of said electrode conductor.

25. The strip assembly of claim 22 wherein said socket of each of said pads further includes a keyway adapted to interfit with a reusable electrode conductor having a key adapted to fit within said keyway to restrain relative movement between said pad and said conductor.

26. The strip assembly of claim 22 wherein said foam sheets have a patient-contacting adhesive on their surfaces engaged with said release liner.

27. The strip assembly of claim 22 wherein said electrolyte gel matrix comprises a hydrogel.

28. The strip assembly of claim 22 wherein said electrolyte gel matrix comprises a urethane hydrogel.

29. For use with reusable electrode conductors, a strip assembly comprising:

a release liner comprising an elongate strip of sheet material formed with a longitudinally-extending center portion bounded by mutually-spaced, longitudinally-extending, upwardly-facing surface portions of said liner; and

a plurality of disposable medical electrode pads aligned in side-by-side relationship on said release liner, each of said pads comprising;

a pair of mutually-spaced foam sheets each located respectively on one of said upwardly facing surface portions of said release liner, each of said foam sheets having a patient-contacting adhesive on their surfaces engaged with said release liner, an electrolyte gel matrix filling the area between said foam sheets and a socket plate adhered to said foam sheets and overlying said gel matrix, said socket plate comprising a sheet of plastic and socket means overlying said gel matrix for removably assembling an electrode conductor in engagement with said gel matrix.

30. The strip assembly of claim 29 wherein said electrolyte gel matrix comprises a hydrogel.

31. The strip assembly of claim 29 wherein said electrolyte gel matrix comprises a urethane hydrogel.

32. The strip assembly of claim 29 wherein said upwardly facing surfaces portions are mutually substantially coplanar and said central portion of said release liner comprises gel matrix-receiving means beneath the plane of said upwardly facing surface portions for enabling parts of said gel matrix to extend below the level of the said foam sheets in addition to filling the area between them.

33. The strip assembly of claim 32 wherein said electrolyte gel matrix comprises a hydrogel.

34. The strip assembly of claim 32 wherein said electrolyte gel matrix comprises a urethane hydrogel.