CA1144606A - Skin contact pellet for bio-electric signal measurement - Google Patents
Skin contact pellet for bio-electric signal measurementInfo
- Publication number
- CA1144606A CA1144606A CA000356681A CA356681A CA1144606A CA 1144606 A CA1144606 A CA 1144606A CA 000356681 A CA000356681 A CA 000356681A CA 356681 A CA356681 A CA 356681A CA 1144606 A CA1144606 A CA 1144606A
- Authority
- CA
- Canada
- Prior art keywords
- pellet
- weight
- skin
- approximate range
- sheet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/25—Bioelectric electrodes therefor
- A61B5/251—Means for maintaining electrode contact with the body
- A61B5/257—Means for maintaining electrode contact with the body using adhesive means, e.g. adhesive pads or tapes
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/25—Bioelectric electrodes therefor
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/25—Bioelectric electrodes therefor
- A61B5/263—Bioelectric electrodes therefor characterised by the electrode materials
- A61B5/265—Bioelectric electrodes therefor characterised by the electrode materials containing silver or silver chloride
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/25—Bioelectric electrodes therefor
- A61B5/263—Bioelectric electrodes therefor characterised by the electrode materials
- A61B5/266—Bioelectric electrodes therefor characterised by the electrode materials containing electrolytes, conductive gels or pastes
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/25—Bioelectric electrodes therefor
- A61B5/263—Bioelectric electrodes therefor characterised by the electrode materials
- A61B5/268—Bioelectric electrodes therefor characterised by the electrode materials containing conductive polymers, e.g. PEDOT:PSS polymers
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Medical Informatics (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Physics & Mathematics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)
- Electrotherapy Devices (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A flexible pellet is disclosed for transmitting bio-electric signals from a skin surface to an electrical conductor. The pellet replaces gel pads and other conductive layers which provide different signal strengths to the monitoring equipment, or in some cases irritate the skin of a patient. The pellet comprises a polymer resin, humectant and water. There is also provided a skin contacting electrode for measuring bio-electric signals comprising a flexible foam sheet having an aperture therethrough. The sheet having an adhesive coated lower surface for contacting the skin, an electrical terminal extending through the aper-ture in the sheet, the terminal being secured to the sheet, and having a substantially flat lower contact surface, an electrical conductive flexible pellet on the lower contact surface of the terminal, the pellet having a skin contacting surface extending flush or beyond the lower surface of the sheet, the pellet adapted to transmit bio-electric signals from the skin to the lower contact surface of the terminal, the pellet comprising a resin, humectant and water.
A flexible pellet is disclosed for transmitting bio-electric signals from a skin surface to an electrical conductor. The pellet replaces gel pads and other conductive layers which provide different signal strengths to the monitoring equipment, or in some cases irritate the skin of a patient. The pellet comprises a polymer resin, humectant and water. There is also provided a skin contacting electrode for measuring bio-electric signals comprising a flexible foam sheet having an aperture therethrough. The sheet having an adhesive coated lower surface for contacting the skin, an electrical terminal extending through the aper-ture in the sheet, the terminal being secured to the sheet, and having a substantially flat lower contact surface, an electrical conductive flexible pellet on the lower contact surface of the terminal, the pellet having a skin contacting surface extending flush or beyond the lower surface of the sheet, the pellet adapted to transmit bio-electric signals from the skin to the lower contact surface of the terminal, the pellet comprising a resin, humectant and water.
Description
This invention relates to medical electrodes. More specifically this invention relates to a bio-electric signal transmitting pellet that may be used with an electrode for ad-herence to the skin of a patient to provide conductive contact between the s~in surface and an electrical conductor, Temporary body electrodes are required for measuring bio-electric signals from the skin of a patient for medical monitoring equipment. Conventionally these electrodes have a conductive male metallic snap fastener element to which may be connected a female snap fastener element and an electrical lead to the monitoring equipment, Medical electrodes presently used today have a thin base layer between the snap fastener element and the skin of a patient, This base layer is formed from some form of conductive material and the electrodes incorporate an adhesive sheet or strip to hold this conductive layer in position on the skin of a patient, Many electrodes used today have gel pads as the conductive layer between the fastener element and the skin, It has been found, however, that gel pads have some limitations, especially if the electrode has to remain on the patient for some time, because the gel is free flowing and can vary in thickness in the pad when the patient moves, This variation in thickness of the gel pad can affect the strength of the bio-electric signal from the skin and hence give an unstable reading on the monitoring equipment. This variation in thickness of the gel pad may occur when the snap fastener element is disconnected and reconnected from the electrical lead because pressure placed on the pad will tend to squeeze the gel forcing it out from under the adhesive portion of the electrode, Furthermore if the gel spills under the adhesive surface or is smeared onto the skin prior to application of the electrode, the adhesion of the electrode to the skin may be affected, Another problem that can occur with gel, is that it dries out, either ~1~4~
during storage or on the skin which has an effect on the signal resolution.
Other attempts have been made to provide a conductive layer between the snap fastener connector and the skin. Some of these include an adhesive pad which has graphite or some other conductor material incorporated with the adhesive. Other types of elements have also been tried, none of these, however, have proved to be completely satisfactory inasmuch as the signal does not remain consistent over a 2 or 3 day period which is often required for monitoring purposes. The reasons for this are many, one such reason is that the conductive layer itself is not a sufficiently good electrical conductor to monitor minor changes in bio-electric signals. Another problem that can exist is that patients who have to wear electrodes for many days are concerned with irritation of the skin due to the contact between the skin and the conductive layer.
We have found that a pellet made from a polymer resin, a humectant, water and in some cases an electrolyte provides a conductive layer which may be used between the skin and the snap fastener element of a monitoring electrode. Such a pellet is flexible but not free flowing, thus it can be used on a curved portion of the body. It retains its shape and, therefore, has little variation in thickness due to either mvvement of the body or connection and disconnection of the electrical lead to the electrode. Furthermore, the flexible pellet contains a humectant which retains water in the pellet itself, thus ensuring that the pellet remains moist and maintains good electrical contact with the skin. Furthermore, if the pellet is left on the patient's skin for a long time the water in the pellet may tend to e~aporate, in which case, the humectant tends to draw water from the skin of the patient to ensure that the conductive properties of the pellet are maintained substantially constant at all times.
Using latex type polymer emulsions, humectant, water and preferrably an electrolyte, it has been found that a solid flexible conductive pellet of any size and shape can be provided.
The thickness of the pellet may be considerably less than the conventional type of gel pads used in electrodes available on the market today, thus the distance between the skin and the snap fastener element of the electrode is reduced resulting in less spurious noise in the signal. The electrode may be small so that it can be used on newborn babies, and does not obstruct placement of other electrodes or other medical devices such as tubes and dressings. A small electrode adheres more easily to curved skin surfaces. Furthermore, a small electrode does not obstruct examination of a patient's chest area or other medical procedures such as defibrillation. Precise placement of a small size of electrode on the skin surface of a patient is an advantage during stress testing procedures.
The present invention provides a flexible pellet for transmitting bio-electric signals from a skin surface to an electrical conductor comprising a polymer resin, a humectant, and water. In a preferred embodiment an electrolyte is added.
The polymer resin may be a suitable latex type polymer emulsion.
Some examples of suitable polymer resins include acrylic, acryl;c esters, methacrylic acid ester, vinyl acetate, acrylic ester-acrylonitrile copolymer, ethylene-vinyl acetate copolymer, vinyl chloride-ethylene-vinyl acetate terpolymer or mixtures thereof.
These examples in no way limit the range of polymer resins suit-able for inclusion in pellets of the present invention. Polymer resin may be in the approximate range of about 50-70% by weight of the pellet. Suitable humectants include but are not limited to, glycerine, triethanolamine, urea, sorbitol or mixtures thereof, and be in the approximate range of about 10-25~ by weight of the pellet. The electrolyte may include metal halides, 60~i nitrates and sulfates such as sodium chloride, potassium chloride, ammonium nitrate, sodium bromide, potassium iodide, silver chloride, magnesium sulfate; other suitable electrolytes include ammonium acetate, sodium citrate, ammonium citrate, zinc citrate and mixtures thereof, or other suitable electrolyte materials and may be in the approximate range of about 1-10% by weight of the pellet, and the water may be in the approximate range of about 10-25% by weight of the pellet.
In another embodiment there is provided a skin con-tacting electrode for measuring bio-electric signals comprising a flexible foam sheet having an aperture therethrough, the sheet having an adhesive coated lower surface for contacting the skin, an electrical terminal extending through the aperture in the sheet, the terminal being secured to the sheet and having a sub-stantially flat lower contact surface, an electrical conductive flexible pellet on the lower contact surface of the terminal, the pellet having a skin contacting surface extending flush or beyond the lower surface of the sheet, the pellet adapted to transmit bio-electric signals from the skin to the lower contact surface of the terminal, the pellet comprising a polymer resin, a humectant, water, and preferably an electrolyte.
In drawings which illustrate embodiments of the invention, Fig. 1 is a vertical cross sectional view of one embodiment of an electrode incorporating the bio~electric signal transmitting pellet of this invention.
Fig. 2 is an exploded view of the components of the electrode shown in Fig. 1.
Figs. 3 and 4 are vertical cross sectional views of other embodiments of an electrode incorporating the bio-electric signal transmitting pellet of the present invention.
Fig. 5 is an isometric view of an electrode attached 1 ~ ~ 160~;
to the skin of a patient.
Fig. 6 is an isometric view of a triangular shaped electrode that may be used with a bio-electric signal trans-mitting pellet of the present invention.
Fig. ~ is an isometric view of an oval shaped elect rode showing aeration holes in the foam sheet.
Bio-electric signal transmitting pellets of the present invention are composed of polymer resin, a humectant, water and in some cases an electrolyte. The polymer resin may be selected from a variety of suitable latex type polymer emulsions such as an aqueous emulsion of acrylic esters or acrylic ester - acrylonitrile copolymer. Suitable polymer emulsions include acrylic - PLEX 4871D (Trade mar~ of Rohm GmbH
Chemische Fabrik), methacrylic acid ester - ROHAFLOC KF-400 (Trade mark of Rohm GmbH Chemische Fabrik), vinyl acetate - C191-103 (Trade mark of Borden Chemicals), epoxy - EC9722 (Trade mark of Borden Chemicals), acrylic ester -acrylonitrile copolymer - DL3260 (Trade mark of Reichhold Chemicals Inc.), ethylene-vinyl acetate copolymer - AIRFLEX 400 (Trade mark of Air Products and Chemicals Inc.), and vinyl chloride-ethylene-~inyl acetate terpolymer -AIRFLEX 456 (Trade mark of Air Products and Chemicals Inc.).
This list covers only a few of the polymer resins suitable for inclusion in pellets of the present invention. The polymer resin in the pellet is preferably in the approximate range of about 50 to 70% by weight of the pellet.
The humectant may be glycerine, triethanolamine, urea, sorbitol and mixtures thereof. This list does not limit the range of suitable humectants. The approximate range of humectant is about 10 to 25% by weight of the pellet. The electrolyte is normally incorporated into the polymer resin in the approximate range of up to about 10% by weight of the total pellet. Examples of suitable electrclytes include metal halides, nitrates and 0~
sulfates such as sodium chloride, potassium chloride, sodium bromide, potassium iodide, ammonium nitrate, silver chloride, magnesium sulfate and the like. Other suitable electrolyte materials include ammonium acetate, sodium citrate, ammonium citrate, zinc citrate and the like. Those skilled in the art can obtain a conductive medium using any one or more of the above-mentioned electrolytes or mixtures thereof. Many other suitable electrolytes may be employed. The water may be dis-tilled, de-ionized or plain tap water. The range of water is normally in the approximate range of about 10 to 25% by weight of the pellet.
Preferred ranges of formulations are as follows, polymer resins about 55 to 65% by weight of the pellet, humectant about 15 to 20% by weight of the pellet, electrolyte about 2 to 5% by weight of the pellet, and water about 15 to 20% by weight of the pelletO
In some cases it has been found that no electrolyte is required in the pellet, but in such cases, higher amounts of humectant and water are required. In one example, 50% by weight polymer resin, 25% by weight humectant and 25% by weight water were formed into a satisfactory pellet. The mixture is formed into whatever shape of pellet is desired. In one embodiment the pellets are substantially flat, and may be any shape, round, square, triangular as required for the electrode. In other embodiments the pellets may have one flat surface for contact with the terminal and a curved surface for contacting the skin of a patient.
~ eferring now to the drawings, one embodiment of an electrode is shown in Figs. 1 and 2 wherein a flexible foam sheet 10 having a large aperture 11 therein has an adhesive composition on its lower surface 12. The adhesive composition is any one of a number of adhesives used for attachment of the sheet 10 to the 6~)~
skin of a patient. A stud 13 of a two part electrical male snap fastener element terminal for connection to a female snap fastener elelnent attached to an electrical lead. The eyelet 14 of the terminal has a post 15 which extends upwards into an aperture on the underneath of the stud 13 and sandwiches a flexible sheet 16 therebetween. The eyelet 14 of the terminal is made from a hard plastic material and is silver plated with a silver chloride coating. The silver chloride coating on the eyelet 14 extends to a substantially flat lower contact sur-face 17 which is contained within the large aperture 11 of the flexible foam sheet 10. The flexible sheet 16 sandwiched be-tween the stud 13 and the eyelet 14 of the electrical terminal has an adhesive on its lower surface which adheres to the top surface of the flexible foam sheet 10.
A bio-electric signal transmitting pellet 18 of the present invention is provided within the aperture 11 of the flexible foam sheet 10. The pellet 18 illustrated is shown in the shape of a round disc. In some cases other shapes, such as square pellets, are suitable especially if they are cut from sheets. The pellet 18 is in contact with the flat lower con-tact surface 17 of the eyelet 14 of the terminal, and is sub-stantially the same area as the eyelet 14 of the terminal. The skin contacting surface 19 of the pellet 18 is flush or extends beyond the lower surface 12 of the foam sheet 10. The electrical conductive pellet 18 is shown as being substantially flat and flexible. It retains its shape in normal use and provides a consistent reproducible stab-e signal with little or no drift in the baseline. The skin contacting surface 19 of the pellet 18 preferably extends in the order of from 1 to 50 thousands of an inch beyond the adhesive lower surface 12 of the foam sheet 10.
Fig, 3 illustrates another embodiment of an electrode which does away with the sheet 16 and sandwiches the flexible 6()6 foam sheet 10 between the stud 13 and the eyelet 14 of the two part terminal. The electrical conductive pellet 18 is located on the substantially flat lower contact surface 17 of the eyelet 14 of the terminal. As can be seen, the skin contacting sur-face 19 of the pellet 18 extends beyond the lower surface 12 of the flexible foam sheet 10, This lower surface 12 of the foam sheet 10 has an adhesive coating thereon to ensure that the sensing element stays in contact with the skin of a patient.
A further embodiment of an electrode is shown in Fig. 4 wherein a one part stud 13A is provided with a sheet 16 adhering to the top of the flat portion of the stud 13A. The flexible foam sheet 10 is the same as shown in Fig. 1, but the pellet 18 has a flat surface for contacting the lower contact surface 17 of the stud 13A and a curved surface for contact with the skin of a patient.
Fig. 5 illustrates an electrode 20 attached to the ar~ 21 of a patient with a snap fastener connector 22 having an electrical lead 23 thereon which leads to a monitoring device.
The shape of electrodes may be round as illustrated in Fig. 2, substantially square with rounded edges as illustrated in Fig. 5, triangular with rounded edges as illustrated in Fig. 6, or oval as shown in Fig. 7. Almost any desired shape of electrodes may be made, Fig. 7 shows an added feature for electrodes which include a number of aeration holes 30 in the foam sheet 10 surrounding the stud 13 and the sheet 16. The aeration holes 30 aid in aerating the skin under the electrode. In general the size of the electrodes of the present invention may be made smaller than those presently available today. When packaged the electrodes have a protective film or release sheet extending over the adhesive surface of the foam sheet 10 protecting the electrical conductive pellet 18 therein. The electrodes are packaged in a sealed envelope to avoid evaporation of water from 11'~'~6~
the pellet 18 durin~ storage. It has been found that if the pellet 18 does dry out, then in view of the humectant material contained therein it re-absorbs water when a drop or more is added, allowin~ the pellet 18 to retain its conductive properties.
EXAMPLES
~ atches of material were made for forming into bio-electric signal transmitting pellets from the following formu-lations:
Percentages 1. Borden C191-103 60 Glycerine 17.5 Ammonium Nitrate 5 Water 17.5
during storage or on the skin which has an effect on the signal resolution.
Other attempts have been made to provide a conductive layer between the snap fastener connector and the skin. Some of these include an adhesive pad which has graphite or some other conductor material incorporated with the adhesive. Other types of elements have also been tried, none of these, however, have proved to be completely satisfactory inasmuch as the signal does not remain consistent over a 2 or 3 day period which is often required for monitoring purposes. The reasons for this are many, one such reason is that the conductive layer itself is not a sufficiently good electrical conductor to monitor minor changes in bio-electric signals. Another problem that can exist is that patients who have to wear electrodes for many days are concerned with irritation of the skin due to the contact between the skin and the conductive layer.
We have found that a pellet made from a polymer resin, a humectant, water and in some cases an electrolyte provides a conductive layer which may be used between the skin and the snap fastener element of a monitoring electrode. Such a pellet is flexible but not free flowing, thus it can be used on a curved portion of the body. It retains its shape and, therefore, has little variation in thickness due to either mvvement of the body or connection and disconnection of the electrical lead to the electrode. Furthermore, the flexible pellet contains a humectant which retains water in the pellet itself, thus ensuring that the pellet remains moist and maintains good electrical contact with the skin. Furthermore, if the pellet is left on the patient's skin for a long time the water in the pellet may tend to e~aporate, in which case, the humectant tends to draw water from the skin of the patient to ensure that the conductive properties of the pellet are maintained substantially constant at all times.
Using latex type polymer emulsions, humectant, water and preferrably an electrolyte, it has been found that a solid flexible conductive pellet of any size and shape can be provided.
The thickness of the pellet may be considerably less than the conventional type of gel pads used in electrodes available on the market today, thus the distance between the skin and the snap fastener element of the electrode is reduced resulting in less spurious noise in the signal. The electrode may be small so that it can be used on newborn babies, and does not obstruct placement of other electrodes or other medical devices such as tubes and dressings. A small electrode adheres more easily to curved skin surfaces. Furthermore, a small electrode does not obstruct examination of a patient's chest area or other medical procedures such as defibrillation. Precise placement of a small size of electrode on the skin surface of a patient is an advantage during stress testing procedures.
The present invention provides a flexible pellet for transmitting bio-electric signals from a skin surface to an electrical conductor comprising a polymer resin, a humectant, and water. In a preferred embodiment an electrolyte is added.
The polymer resin may be a suitable latex type polymer emulsion.
Some examples of suitable polymer resins include acrylic, acryl;c esters, methacrylic acid ester, vinyl acetate, acrylic ester-acrylonitrile copolymer, ethylene-vinyl acetate copolymer, vinyl chloride-ethylene-vinyl acetate terpolymer or mixtures thereof.
These examples in no way limit the range of polymer resins suit-able for inclusion in pellets of the present invention. Polymer resin may be in the approximate range of about 50-70% by weight of the pellet. Suitable humectants include but are not limited to, glycerine, triethanolamine, urea, sorbitol or mixtures thereof, and be in the approximate range of about 10-25~ by weight of the pellet. The electrolyte may include metal halides, 60~i nitrates and sulfates such as sodium chloride, potassium chloride, ammonium nitrate, sodium bromide, potassium iodide, silver chloride, magnesium sulfate; other suitable electrolytes include ammonium acetate, sodium citrate, ammonium citrate, zinc citrate and mixtures thereof, or other suitable electrolyte materials and may be in the approximate range of about 1-10% by weight of the pellet, and the water may be in the approximate range of about 10-25% by weight of the pellet.
In another embodiment there is provided a skin con-tacting electrode for measuring bio-electric signals comprising a flexible foam sheet having an aperture therethrough, the sheet having an adhesive coated lower surface for contacting the skin, an electrical terminal extending through the aperture in the sheet, the terminal being secured to the sheet and having a sub-stantially flat lower contact surface, an electrical conductive flexible pellet on the lower contact surface of the terminal, the pellet having a skin contacting surface extending flush or beyond the lower surface of the sheet, the pellet adapted to transmit bio-electric signals from the skin to the lower contact surface of the terminal, the pellet comprising a polymer resin, a humectant, water, and preferably an electrolyte.
In drawings which illustrate embodiments of the invention, Fig. 1 is a vertical cross sectional view of one embodiment of an electrode incorporating the bio~electric signal transmitting pellet of this invention.
Fig. 2 is an exploded view of the components of the electrode shown in Fig. 1.
Figs. 3 and 4 are vertical cross sectional views of other embodiments of an electrode incorporating the bio-electric signal transmitting pellet of the present invention.
Fig. 5 is an isometric view of an electrode attached 1 ~ ~ 160~;
to the skin of a patient.
Fig. 6 is an isometric view of a triangular shaped electrode that may be used with a bio-electric signal trans-mitting pellet of the present invention.
Fig. ~ is an isometric view of an oval shaped elect rode showing aeration holes in the foam sheet.
Bio-electric signal transmitting pellets of the present invention are composed of polymer resin, a humectant, water and in some cases an electrolyte. The polymer resin may be selected from a variety of suitable latex type polymer emulsions such as an aqueous emulsion of acrylic esters or acrylic ester - acrylonitrile copolymer. Suitable polymer emulsions include acrylic - PLEX 4871D (Trade mar~ of Rohm GmbH
Chemische Fabrik), methacrylic acid ester - ROHAFLOC KF-400 (Trade mark of Rohm GmbH Chemische Fabrik), vinyl acetate - C191-103 (Trade mark of Borden Chemicals), epoxy - EC9722 (Trade mark of Borden Chemicals), acrylic ester -acrylonitrile copolymer - DL3260 (Trade mark of Reichhold Chemicals Inc.), ethylene-vinyl acetate copolymer - AIRFLEX 400 (Trade mark of Air Products and Chemicals Inc.), and vinyl chloride-ethylene-~inyl acetate terpolymer -AIRFLEX 456 (Trade mark of Air Products and Chemicals Inc.).
This list covers only a few of the polymer resins suitable for inclusion in pellets of the present invention. The polymer resin in the pellet is preferably in the approximate range of about 50 to 70% by weight of the pellet.
The humectant may be glycerine, triethanolamine, urea, sorbitol and mixtures thereof. This list does not limit the range of suitable humectants. The approximate range of humectant is about 10 to 25% by weight of the pellet. The electrolyte is normally incorporated into the polymer resin in the approximate range of up to about 10% by weight of the total pellet. Examples of suitable electrclytes include metal halides, nitrates and 0~
sulfates such as sodium chloride, potassium chloride, sodium bromide, potassium iodide, ammonium nitrate, silver chloride, magnesium sulfate and the like. Other suitable electrolyte materials include ammonium acetate, sodium citrate, ammonium citrate, zinc citrate and the like. Those skilled in the art can obtain a conductive medium using any one or more of the above-mentioned electrolytes or mixtures thereof. Many other suitable electrolytes may be employed. The water may be dis-tilled, de-ionized or plain tap water. The range of water is normally in the approximate range of about 10 to 25% by weight of the pellet.
Preferred ranges of formulations are as follows, polymer resins about 55 to 65% by weight of the pellet, humectant about 15 to 20% by weight of the pellet, electrolyte about 2 to 5% by weight of the pellet, and water about 15 to 20% by weight of the pelletO
In some cases it has been found that no electrolyte is required in the pellet, but in such cases, higher amounts of humectant and water are required. In one example, 50% by weight polymer resin, 25% by weight humectant and 25% by weight water were formed into a satisfactory pellet. The mixture is formed into whatever shape of pellet is desired. In one embodiment the pellets are substantially flat, and may be any shape, round, square, triangular as required for the electrode. In other embodiments the pellets may have one flat surface for contact with the terminal and a curved surface for contacting the skin of a patient.
~ eferring now to the drawings, one embodiment of an electrode is shown in Figs. 1 and 2 wherein a flexible foam sheet 10 having a large aperture 11 therein has an adhesive composition on its lower surface 12. The adhesive composition is any one of a number of adhesives used for attachment of the sheet 10 to the 6~)~
skin of a patient. A stud 13 of a two part electrical male snap fastener element terminal for connection to a female snap fastener elelnent attached to an electrical lead. The eyelet 14 of the terminal has a post 15 which extends upwards into an aperture on the underneath of the stud 13 and sandwiches a flexible sheet 16 therebetween. The eyelet 14 of the terminal is made from a hard plastic material and is silver plated with a silver chloride coating. The silver chloride coating on the eyelet 14 extends to a substantially flat lower contact sur-face 17 which is contained within the large aperture 11 of the flexible foam sheet 10. The flexible sheet 16 sandwiched be-tween the stud 13 and the eyelet 14 of the electrical terminal has an adhesive on its lower surface which adheres to the top surface of the flexible foam sheet 10.
A bio-electric signal transmitting pellet 18 of the present invention is provided within the aperture 11 of the flexible foam sheet 10. The pellet 18 illustrated is shown in the shape of a round disc. In some cases other shapes, such as square pellets, are suitable especially if they are cut from sheets. The pellet 18 is in contact with the flat lower con-tact surface 17 of the eyelet 14 of the terminal, and is sub-stantially the same area as the eyelet 14 of the terminal. The skin contacting surface 19 of the pellet 18 is flush or extends beyond the lower surface 12 of the foam sheet 10. The electrical conductive pellet 18 is shown as being substantially flat and flexible. It retains its shape in normal use and provides a consistent reproducible stab-e signal with little or no drift in the baseline. The skin contacting surface 19 of the pellet 18 preferably extends in the order of from 1 to 50 thousands of an inch beyond the adhesive lower surface 12 of the foam sheet 10.
Fig, 3 illustrates another embodiment of an electrode which does away with the sheet 16 and sandwiches the flexible 6()6 foam sheet 10 between the stud 13 and the eyelet 14 of the two part terminal. The electrical conductive pellet 18 is located on the substantially flat lower contact surface 17 of the eyelet 14 of the terminal. As can be seen, the skin contacting sur-face 19 of the pellet 18 extends beyond the lower surface 12 of the flexible foam sheet 10, This lower surface 12 of the foam sheet 10 has an adhesive coating thereon to ensure that the sensing element stays in contact with the skin of a patient.
A further embodiment of an electrode is shown in Fig. 4 wherein a one part stud 13A is provided with a sheet 16 adhering to the top of the flat portion of the stud 13A. The flexible foam sheet 10 is the same as shown in Fig. 1, but the pellet 18 has a flat surface for contacting the lower contact surface 17 of the stud 13A and a curved surface for contact with the skin of a patient.
Fig. 5 illustrates an electrode 20 attached to the ar~ 21 of a patient with a snap fastener connector 22 having an electrical lead 23 thereon which leads to a monitoring device.
The shape of electrodes may be round as illustrated in Fig. 2, substantially square with rounded edges as illustrated in Fig. 5, triangular with rounded edges as illustrated in Fig. 6, or oval as shown in Fig. 7. Almost any desired shape of electrodes may be made, Fig. 7 shows an added feature for electrodes which include a number of aeration holes 30 in the foam sheet 10 surrounding the stud 13 and the sheet 16. The aeration holes 30 aid in aerating the skin under the electrode. In general the size of the electrodes of the present invention may be made smaller than those presently available today. When packaged the electrodes have a protective film or release sheet extending over the adhesive surface of the foam sheet 10 protecting the electrical conductive pellet 18 therein. The electrodes are packaged in a sealed envelope to avoid evaporation of water from 11'~'~6~
the pellet 18 durin~ storage. It has been found that if the pellet 18 does dry out, then in view of the humectant material contained therein it re-absorbs water when a drop or more is added, allowin~ the pellet 18 to retain its conductive properties.
EXAMPLES
~ atches of material were made for forming into bio-electric signal transmitting pellets from the following formu-lations:
Percentages 1. Borden C191-103 60 Glycerine 17.5 Ammonium Nitrate 5 Water 17.5
2. Borden EC9722 62.2 Urea 8.6 Magnesium Sulfate 4.2 Water 25,0
3. Rohm Rohafloc KF-400 50 Glycerine 25 Water 25
4. Air Products Airflex 456 70 Triethanolamine 12 Zinc Citrate 6 Water 12
5. Airflex 100 HS 60 Urea 20 Ammonium Acetate 5 Water 15
6. Rohafloc KF 400 15 Reichhold DL-3260 45 Triethanolamine 17 Sodium Sulfate 2.5 Water 20.5
7. Rohafloc KF 400 4 Reichhold DL-3260 56 Glycerine 15 Potassium Chloride 5 Water 20
8. Reichhold DL-3260 60 Glycerine 17 ` Sodium Chloride 5 Water 18
9. Reichhold DL-3260 55 Urea 10 Potassium Nitrate 10 Water 25 6(:)t;
10. Borden EC 97~2 62.5 Triethanolamine 10 Urea 10 Ammonium Chloride 2.5 Water 15
11. Reichhold DL-3260 60 Glycerine 17.5 Zinc Citrate 2.5 Sodium Chloride 2.5 Water 17.5
12. Borden EC 9722 60 Sorbitol 15 Potassium Chloride 5 Water 20
13. Airflex 456 70 Sorbitol 10 Potassium Chloride 4 Water 16
14. Borden C191-103 52.4 Sorbitol 7.1 Glycerine 7.1 Magnesium Sulfate 9.5 Water 23.9
15. Airflex 456 60 Rohafloc KF-400 5 Triethanolamine 15 Sodium Chloride 6 Water 14
16. PLEX 4871D 55 Glycerine 15 Potassium Chloride 2.5 Water 17.5 The formulations were formed into pellets approximately 1/16 inch thick. Some of the pellets were made into round discs, some were made into square pellets. In each case the area of the pellet was about the same as the lower contact surface of a snap fastener terminal. Electrodes were prepared similar to those shown in the drawings and tested for conductivity. All the samples were satisfactory, and performed as well or better than present day commercially available electrodes.
Although the invention has been described by reference to specific materials forming the conductive pellets and specific electrode designs, it is not intended that the invention be limited thereby but that modifications to the above-described invention are intended to be included as falling within the _ 10 --11~41;06 broad scope and spirit of the invention,
Although the invention has been described by reference to specific materials forming the conductive pellets and specific electrode designs, it is not intended that the invention be limited thereby but that modifications to the above-described invention are intended to be included as falling within the _ 10 --11~41;06 broad scope and spirit of the invention,
Claims (8)
1. A flexible pellet for transmitting bio-electric signals from a skin surface to an electrical conductor, the pellet formed from solid material and being non-adhesive, comprising in combination a polymer resin selected from the group consisting of acrylic, acrylic esters, methacrylic acid ester, vinyl acetate, acrylic ester-acrylonitrile copolymer, ethylene-vinyl acetate copolymer, vinyl chloride-ethylene-vinyl acetate terpolymer or mixtures thereof; humectant selected from the group consisting of glycerine, triethanolamine, urea, sorbitol or mixtures thereof; electrolyte selected from the group consisting of metal halides, nitrates and sulfates, sodium chloride, potassium chloride, sodium bromide, potassium iodide, ammonium nitrate, silver chloride, magnesium sulfate, ammonium citrate, zinc citrate, ammonium acetate, sodium citrate or mixtures thereof; and water.
2. The pellet according to claim 1, wherein the polymer resin is in the approximate range of about 50-70% by weight of the pellet, the humectant is in the approximate range of about 10-25% by weight of the pellet, the electrolyte is in the approxi-mate range of about 1-10% by weight of the pellet, and the water is in the approximate range of about 10-25% by weight of the pellet.
3. The pellet according to claim 1, wherein the polymer resin is in the approximate range of about 55-65% by weight of the pellet, the humectant is in the approximate range of about 15-20% by weight of the pellet, the electrolyte is in the approximate range of about 2-5% by weight of the pellet, and the water is in the approximate range of about 15-20% by weight of the pellet.
4. A skin contacting electrode for measuring bio-electric signals comprising, a flexible foam sheet having an aperture therethrough the sheet having an adhesive coated lower surface for contacting the skin, an electrical terminal extending through the aperture in the sheet, the terminal being secured to the sheet, and having a substantially flat lower contact surface, an electrical conductive flexible pellet on the lower contact surface of the terminal, the pellet having a skin con-tacting surface extending flush or beyond the lower surface of the sheet, the pellet adapted to transmit bio-electric signals from the skin to the lower contact surface of the terminal, the pellet formed from a solid material and being non-adhesive, the pellet comprising in combination, a polymer resin selected from the group consisting of acrylic, acrylic esters, methacrylic acid ester, vinyl acetate, acrylic ester-acrylonitrile copolymer, ethylene-vinyl acetate copolymer, vinyl chloride-ethylene-vinyl acetate terpolymer or mixtures thereof; humectant selected from the group consisting of glycerine, triethanola-mine, urea, sorbitol or mixtures thereof; electrolyte selected from the group consisting of metal halides, nitrates and sulfates, sodium chloride, potassium chloride, sodium bromide, potassium iodide, ammonium nitrate, silver chloride, magnesium sulfate, ammonium citrate, zinc citrate, ammonium acetate, sodium citrate or mixtures thereof; and water.
5. The electrode according to claim 4 wherein the pellet has substantially the same area as the lower contact surface of the terminal.
6. The electrode according to claim 4 wherein the electrical conductive pellet has the polymer resin in the approximate range of about 50-70% by weight of the pellet, the humectant is in the approximate range of about 10-25% by weight ]
of the pellet, the electrolyte is in the approximate range of about 1-10% by weight of the pellet, and the water is in the approximate range of about 10-25% by weight of the pellet.
of the pellet, the electrolyte is in the approximate range of about 1-10% by weight of the pellet, and the water is in the approximate range of about 10-25% by weight of the pellet.
7. The electrode according to claim 4 wherein the electrical conductive pellet has the polymer resin in the approximate range of about 55-65% by weight of the pellet, the humectant is in the approximate range of about 15-20% by weight of the pellet, the electrolyte is in the approximate range of about 2-5% by weight of the pellet, and the water is in the approximate range of about 15-20% by weight of the pellet.
8. The electrode according to any of claim 4 or claim 5 including a plurality of aeration holes in the flexible foam sheet surrounding the electrical terminal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000356681A CA1144606A (en) | 1980-07-22 | 1980-07-22 | Skin contact pellet for bio-electric signal measurement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000356681A CA1144606A (en) | 1980-07-22 | 1980-07-22 | Skin contact pellet for bio-electric signal measurement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1144606A true CA1144606A (en) | 1983-04-12 |
Family
ID=4117478
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000356681A Expired CA1144606A (en) | 1980-07-22 | 1980-07-22 | Skin contact pellet for bio-electric signal measurement |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1144606A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0168917A1 (en) * | 1984-05-07 | 1986-01-22 | Lloyd A. Ferreira | Conductive material and biomedical electrode |
| WO1986005083A1 (en) * | 1985-03-01 | 1986-09-12 | Arbo Gmbh Medizin-Technologie | Bioelectrical electrode |
| US4979517A (en) * | 1988-02-01 | 1990-12-25 | Physio-Control Corporation | Disposable stimulation electrode with long shelf life and improved current density profile |
| WO1995005772A1 (en) * | 1993-08-27 | 1995-03-02 | Micron Medical Products, Inc. | Medical electrode |
| US6673852B1 (en) * | 1995-07-11 | 2004-01-06 | Nihon Kohden Corporation | Conductive composition for biological electrode |
-
1980
- 1980-07-22 CA CA000356681A patent/CA1144606A/en not_active Expired
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0168917A1 (en) * | 1984-05-07 | 1986-01-22 | Lloyd A. Ferreira | Conductive material and biomedical electrode |
| WO1986005083A1 (en) * | 1985-03-01 | 1986-09-12 | Arbo Gmbh Medizin-Technologie | Bioelectrical electrode |
| US5024227A (en) * | 1985-03-01 | 1991-06-18 | Arbo Medizin-Technologie Gmbh | Bioelectrical electrode |
| US4979517A (en) * | 1988-02-01 | 1990-12-25 | Physio-Control Corporation | Disposable stimulation electrode with long shelf life and improved current density profile |
| WO1995005772A1 (en) * | 1993-08-27 | 1995-03-02 | Micron Medical Products, Inc. | Medical electrode |
| US5489215A (en) * | 1993-08-27 | 1996-02-06 | Micron Medical Products, Inc. | Medical electrode |
| US5499628A (en) * | 1993-08-27 | 1996-03-19 | Micron Medical Products, Inc. | Medical electrode |
| US6673852B1 (en) * | 1995-07-11 | 2004-01-06 | Nihon Kohden Corporation | Conductive composition for biological electrode |
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