Compositions for disposable bio-medical electrodes

• US 5,686,516 A
• Filed: 06/15/1995
• Issued: 11/11/1997
• Est. Priority Date: 07/24/1994
• Status: Expired due to Fees

• Current Assignee: SLP Scientific Laboratory Products Limited
• Original Assignee: SLP Scientific Laboratory Products Limited
• Inventors: Tzur, Yoel
• Primary Examiner(s): Lee, Helen
• Application Number:
  US08/490,675
• Time in Patent Office: 880 Days
• Field of Search: 524/394, 524/403, 524/436, 524/437, 524/447, 524/492, 524/493, 524/495, 428/356
• US Class Current: 524/394
• CPC Class Codes: A61B 5/259 using conductive adhesive means, e.g. gels
• CPC Class Codes: A61B 5/291 for electroencephalography [EEG]
• CPC Class Codes: Y10T 428/2857 including metal or compound thereof or natural rubber

Abstract

The present invention relates to a disposable electrode for providing electrical contact with a patient'"'"'s scalp or skin during routine EEG or EKG tests, as well as EEG during full sleeping period in order to record electrical brain or skin waves, which comprises an electrically conductive composition having a volume resistivity in the range of between 1000 to 1500 ohms, acting also as an adhesive to the skin or the scalp by its remoistable property. The composition comprises: (1) a partially hydrolysed polyvinyl alcohol; (2) a highly hygroscopic salt selected from an metal salt, or organic chloride salt; (3) a highly electrolytic salt, and (4) a metal powder selected from aluminium, bronze and silver. The performance of the electrode was found to be the same as those known on the market.

Claims

1. A disposable electrode for providing electrical contact with a patient'"'"'s skin or scalp during sleeping, in order to record electrical waves or brain waves, which comprises an electrically conductive composition having a volume resistivity in the range of between 1000 to 1500 ohms, said composition acting also as an adhesive to the skin or scalp by its remoistable property and comprising:

a polyvinyl alcohol hydrolysed to an extent of above 72% and present in an amount between 20% and 75% by weight of the composition;

a highly hygroscopic salt selected from the group consisting of magnesium chloride, calcium chloride, aluminum chloride, an alkali metal citrates, an alkali metal acetate and mixtures thereof;

said hygroscopic salt being present in an amount between 3% and 35% by weight of the composition;

a highly electrolytic, alkali metal salt selected from the group consisting of sodium chloride and potassium chloride, said electrolyte alkali metal salt being present in an amount between 1% and 5% by weight of the composition; and

a metal powder selected from the group consisting of aluminum, bronze and silver, said metal powder being present in an amount between 1% and 10% by weight of the composition.

2. The disposable electrode according to claim 1, wherein said polyvinyl alcohol is hydrolysed to an extent of between 80% to 90%.

3. The disposable electrode according to claim 1, wherein the amount of the hydrolysed polyvinyl alcohol in said composition, is in the range of between 20% to 75% by weight.

4. The disposable electrode according to claim 1, wherein said highly hygroscopic salt is an organic salt selected from the group consisting of an alkali metal citrate or acetate.

5. The disposable electrode according to claim 1, wherein said highly hygroscopic salt is selected from the group consisting of a hydrated magnesium chloride, calcium chloride, aluminum chloride and any mixture thereof.

6. The disposable electrode according to claim 1 wherein said electrode is connected with carbon fibres conducting leads.

7. The disposable electrode according to claim 1, wherein said composition contains a thixotropic agent which prevents the settling of the metal powder thus controlling the flow properties of the conductive composition and improving the tackiness of the composition.

8. The disposable electrode according to claim 7, wherein said thixotropic agent is selected from the group consisting of fumed silica oxide, precipitated silica oxide and bentonite.

9. The disposable electrode according to claim 1, wherein an antifoaming compound is added.

10. The disposable electrode according to claim 9, wherein said antifoaming compound is selected from a blend of paraffin oil and non-ionic emulsifiers.