Medical electrode and method

• US 5,520,683 A
• Filed: 05/16/1994
• Issued: 05/28/1996
• Est. Priority Date: 05/16/1994
• Status: Expired due to Fees

• Current Assignee: Physiometrix, Inc. (Pfizer Inc.)
• Original Assignee: Physiometrix, Inc. (Pfizer Inc.)
• Inventors: Barnett, Donald E. Jr., Subramaniam, Raj, Clare, Christopher R.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US08/243,226
• Time in Patent Office: 743 Days
• Field of Search: 606/32, 607/142, 607/149, 607/152, 607/153
• US Class Current: 606/32
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61N 1/048 Electrodes characterised by a specific connection between lead and electrode
• CPC Class Codes: A61N 1/0492 Patch electrodes A61N1/0412, A61N1/0428 take precedence

Abstract

A medical electrode for use with a power supply for providing a more uniform current distribution for contacting an exposed surface of skin of a living body comprising a flexible carrier layer formed of an insulating material. A layer of conductive material is carried by the carrier layer. The layer of conductive material is separated into at least two segments with a space therebetween so that the two segments are electrically isolated from each other. A continuous layer of hydrogel material overlies the segments and is disposed in said space. The hydrogel material has a resistivity greater than the resistivity of the skin of the patient. A connector is adapted to be connected to the source of power whereby substantially equal current flow can be achieved from each segment through the skin of the patient without sharp transitions in current flow between the segments and the space between the segments.

Claims

1. A low impedance medical electrode for use in defibrillation electrocautery and electrosurgery and for use with a power supply for providing a more uniform current distribution for contacting an exposed surface of skin of a living body of a patient comprising a flexible carrier layer formed of an insulating material, a layer of conductive material carried by the carrier layer, said layer of conductive material being separated into at least two segments with a space therebetween so that the two segments are electrically isolated from each other, a continuous layer of hydrogel material containing an electrolyte overlying said segments and being disposed in said space, said hydrogel material having a bulk resistivity of less than 250 ohm centimeters and connector means connected to the segments and adapted to be connected to the power supply whereby substantially equal current flow can be achieved from each segment through the skin of the patient without sharp transitions in current flow between the segments and the space between the segments, said connector means including at least one resistor having a resistivity of no greater than approximately 9.5 ohms for controlling the flow of current in one segment with respect to the other segment.

2. An electrode as in claim 1 together with a removable release liner disposed over the hydrogel material.

3. An electrode as in claim 1 wherein said layer of conductive material is formed of aluminum.

4. An electrode as in claim 3 wherein said hydrogel is substantially oxygen free and has a pH ranging from 4-10 and serving to protect the aluminum from corrosion.

5. An electrode as in claim 4 wherein said pH is approximately 8.5.

6. A medical electrode comprising a flexible carder layer formed of an insulating material, an aluminum electrode carried by the flexible carrier layer having an exposed surface and a hydrogel material overlying the exposed surface of the aluminum electrode and being in contact therewith, said hydrogel material being substantially free of oxygen, said hydrogel material having a pH ranging from 4-9 to reduce the corrosion of the aluminum to a minimum.

7. A medical electrode for use with a power supply for making contact to an exposed surface of skin of a living body of a patient comprising a flexible carrier layer formed of an insulating material, said flexible carrier layer having an outer perimeter, said flexible carrier layer having a plurality of spaced-apart openings formed in the flexible carrier layer near the outer perimeter, said openings being generally triangular in shape and having bases and apices with said bases being disposed adjacent the outer perimeter and with said apices facing inwardly away from the outer perimeter, a layer of conductive material carried by the carrier layer, said layer of conductive material being separated into at least two segments with a space therebetween so that the two segments are electrically isolated from each other, a continuous layer of hydrogel material containing an electrolyte overlying said segments and being disposed in said space, said hydrogel material having a bulk resistivity of less than 250 ohm centimeters and connector means, including at least one resistor having a resistivity of no greater than approximately 9.5 ohms connected to the segments adapted to be connected to the power supply, the openings in the flexible carrier layer serving to permit the medical electrode to readily conform to the contours of the skin of the patient to which it is applied.