United States Patent 3710782

Method of applying a composition in aerosol form for use with electromedical devices, such as, electrocardiographic and electroencephalographic devices, the composition being used to treat the tissue before application of electrodes to clean it and render it electroconductive, and comprising an aerosol propellant carrying a solution of an alkali metal salt of an organic acid inn alcohol.

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A61B5/0408; (IPC1-7): A61B5/04
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Primary Examiner:
Kamm, William E.
What is claimed is

1. A method of treating human skin preparatory to application of an electrode thereto, comprising the steps of:

2. A method in accordance with claim 1 wherein said composition comprises from about 30-95 weight percent of a lower alkyl alcohol and about 1-40 weight percent of an alkali metal salt of an organic acid.

3. A method in accordance with claim 2 in which the organic acid is a member selected from the group consisting of formic, acetic, propionic, citric, lactic and stearic acids.

4. A method in accordance with claim 3 in which the acid is a member selected from the group consisting of lower alkyl organic acids.

5. A method in accordance with claim 2 to which is added from about 5-50 weight percent of a polyhalogen substituted lower alkane as an aerosol propellant.

6. A method in accordance with claim 5 in which the alcohol is ethyl alcohol, the organic salt is potassium acetate and the aerosol propellent is dichloro-difluoro methane.

7. A method in accordance with claim 6 wherein the ingredients named therein are in the proportions of 30 grams of ethyl alcohol, 10 grams of potassium acetate, and 12 grams of dichloro-difluoro methane.


The invention is related to the electromedical art in which electrical signals generated by various parts of the anatomy, such as, the heart or brain, are monitored by electromedical apparatus to study various conditions of the part of the anatomy being monitored. In this art it is essential that the contact between the tissue and the electrode connected to the recording apparatus have a low resistance and provide the highest degree of conductivity. Accordingly, the electrode contact area of the tissue should be entirely free of skin oil and otherwise clean. According to prior art practices in which the electrode is attached to the tissue by a conductive paste, an electrolyte, such as, sodium chloride, is included in the paste. Typical of such electroconductive pastes is one sold commercially as Beckman Offner Paste made of glycerin, gum tragaranth and benzyl alcohol and including sodium chloride as an electrolyte. The electrolyte increases the electrical conductivity of the skin and thereby improves the transmission of electrical signals through the skin. Another paste of this type is one sold under the trade name of EKG-Sol by Burton Parsons and Company of Washington, D.C. Use of the pastes is normally preceded by use of alcohol to remove skin oils, etc.

In order to use the available electroconductive pastes incorporating an electrolyte many electrodes are designed with a reservoir-like arrangement to contain the electrolyte. Patents disclosing electrodes of this type are U.S. Pat. Nos. 2,555,037; 2,872,926; 2,985,172; 3,085,577 and 3,187,745. These electrodes are complicated in structure, expensive to manufacture and have other disadvantages over flat type bonded contact electrodes, such as, those disclosed in copending U.S. patent application Ser. No. 735,394 for "Biological Electrode and Method of Making Same" filed in the U.S. Patent Office on June 7, 1968, now U.S. Pat. No. 3,565,059.

The prior art electroconductive pastes are inefficient with flat contact bonded electrodes as disclosed in the above referred to patent application for the reason that an adherent surface must be left on the tissue contact area in the use of the latter type electrodes and the pastes obstruct this and must be wiped off before application of flat type bonded electrodes.

Accordingly, it is a principal objective of this invention to provide a method of applying a composition for application to the electrode contact area of the tissue which provides skin oil removal, electrolyte penetration into the skin and leaves no residue on the skin to obstruct adherence of the electrode.


Method of applying a composition which comprises an aerosol propellant which is a polyhalogen substituted lower alkane carrying an alcohol solution of a salt of an alkali metal and an organic acid. The preferred propellant is dichlorodifluoro methane sold commercially as Freon 12. The preferred alcohol is ethyl alcohol, and the preferred salt is potassium acetate.


In application, the composition of the invention is sprayed upon the human tissue and allowed to penetrate for a few seconds before the application of flat type electrodes by spraying or bonding. The composition may then be wiped off before application of the electrodes.

It is preferred to use the composition in the form of an aerosol, the preferred aerosol being Freon 12. Other polyhalogen substituted lower alkanes and mixed polyhalogen substituted lower alkanes may be used, such as, the other freons. Although the preferred alcohol is ethyl alcohol, other suitable solvent alcohols are the lower alkyl alcohols, such as, methyl, propyl and octyl; while potassium acetate is the preferred salt, other alkali metal salts of organic acids may be used. These include the sodium and potassium salts of formic, propionic, citric lactic and stearic acids, and other salts of these metals, such as, sodium or potassium methyl or ethyl sulfate. The amount of alcohol may vary from 30 to 95 weight percent, depending upon the solubility of the salts, the amount of the salt in the composition may vary from 1 to 40 weight percent depending upon its solubility and sufficient propellant must be used to create a satisfactory aerosol. The amount of propellant will preferably vary from about 5 to about 50 weight percent.

The following examples are illustrative of the invention but not limiting thereof.


A 2 ounce aerosol was prepared having the following composition:

Component Amount Ethyl Alcohol 30 grams Potassium Acetate 10 grams Freon 12 (Propellant) 12 grams

A portion of the above solution was sprayed onto an area of human skin and allowed to penetrate for a few seconds. The electrical resistance of the treated skin was measured and found to be comparable to that obtained with Beckman Offner Paste and EKG-Sol, the commercial preparations.


Another portion of the above composition was sprayed onto a human chest in proper locations for attachment of the "Lifesaver" electrodes (patent application Ser. No. 735,394), and various size electrodes tested on the treated area. Electrical impedance of electrodes 0.70 inches in diameter between pairs of electrodes has ranged from 50,000 ohms to 900,000 ohms in a large number of experiments ranging in duration from one minute to 72 hours.

The above results illustrate the effectiveness of the composition in skin oil removal and electolyte penetration into the skin. The electrical impedance characteristics of the bonded electrodes which were obtained show that there was good electrolyte penetration of the skin and low resistance contact between the skin and the electrodes. The alkali metal salt is an excellent electrolyte and the alcohol functions not only as a solvent for the salt but also as a skin oil removal agent. It is thus seen that the composition provides in one medium a skin oil cleanser and electrolyte and leaves no residue which interferes with the contact between the electrode and the skin.