# US 8,019,401 B1 · Stretchable electrode and method of making physiologic measurements > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,019,401 B1 - Document ID: US8019401B1 - Status: Granted - Kind: B1 - Application number: 11/633,077 - Filed: 2006-12-04 - Granted: 2011-09-13 - Earliest claimed: 2006-12-04 - Assignees: Smithmarks, Inc. - Inventors: Michael Smith; Lloyd Marks - Web page: https://patentgrep.com/patent/US8019401B1 ## CPC - A61B 5/0535: Impedance plethysmography (for measuring blood flow A61B5/0295) - A61B 2562/164: the sensor is mounted in or on a conformable substrate or carrier - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A stretchable electrode for use in physiologic measurements on a human body, such as peripheral impedance plethysmography, is disclosed. One embodiment of the stretchable electrode comprises an uninsulated stainless steel wire braid formed into a tubular conductor surrounding an elastic core and attached to an elastic substrate or base. Other embodiments of the stretchable electrode include a garter spring, a flat braided or woven conductor and an undulating wire. The electrode is placed about a limb of a human body and elastically stretched so that the conductor is in substantially continuous circumferential electrical contact with the skin of the limb. A method of attaching the stretchable electrode to the limb of a human body is also disclosed. ## Claims ### Claim 1 An electrode for making electrical contact with the skin comprising an uninsulated metal conductor adapted to make electrical contact with the skin, said conductor having a longitudinal axis and being elastically stretchable along said axis, wherein said metal conductor comprises a plurality of metal wires woven into a tube which is disposed about an elastic core. ### Claim 2 (depends on 1) The electrode of claim 1, wherein said metal wires are braided into a tubular form and disposed about the elastic core. ### Claim 3 (depends on 1) The electrode of claim 1, wherein said metal wires are stainless steel and the elastic core is a synthetic rubber cord or tube. ### Claim 4 (depends on 1) The electrode of claim 1, wherein said metal conductor has a circular cross-section. ### Claim 5 (depends on 1) The electrode of claim 1, wherein said metal conductor is attached to an elastic substrate. ### Claim 6 (depends on 5) The electrode of claim 5, wherein said metal conductor is attached to said elastic substrate by an adhesive or by stitching. ### Claim 7 (depends on 5) The electrode of claim 5, wherein said elastic substrate is moisture impervious. ### Claim 8 (depends on 5) The electrode of claim 5, wherein said elastic substrate has opposite sides provided with hook and loop material for fastening the metal conductor about the limb of a human subject in an elastically stretched condition of the conductor and with the conductor in substantially continuous circumferential electrical contact with the skin of the limb. ### Claim 9 (depends on 1) The electrode of claim 1, wherein said electrode is sterilizable and reusable. ### Claim 10 An electrode for making electrical contact with the skin, including four conductors arranged in parallel in a quadripolar array for making peripheral plethysmograph measurements, each of said conductors being an uninsulated metal conductor adapted to make electrical contact with the skin, each of said conductors having a longitudinal axis and being elastically stretchable along said axis, said conductors being attached to an elastic substrate and means affixed to said substrate for fastening said conductors about a limb of a subject with the conductors in an elastically stretched condition. ### Claim 11 (depends on 10) The electrode of claim 10, wherein the conductors are grouped in pairs. ### Claim 12 (depends on 11) The electrode of claim 11, further comprising a bridge connecting the pairs of the conductors. ### Claim 13 A stretchable electrode adapted for encircling a body portion of a subject and making substantially continuous circumferential electrical contact with the skin of the body portion, comprising an uninsulated metal conductor having a longitudinal axis, said conductor being elastically stretchable along said axis, wherein said metal conductor comprises a plurality of metal wires woven into a tube which is disposed about an elastic core. ### Claim 14 (depends on 13) The electrode of claim 13, wherein said metal conductor is made of a stainless steel wire braid formed into a tube surrounding an elastic core and means connected to said conductor for fastening said electrode about the body portion with the metal conductor in its elastically stretched condition. ### Claim 15 An electrode for making physiologic measurements of the human body comprising a plurality of metal wires braided into a tubular conductor having a longitudinal axis, an elastic core disposed inside said tubular conductor along said longitudinal axis, and means for attaching the tubular conductor to a portion of the body in an elastically stretched condition with the conductor in substantially continuous electrical contact with the skin of the body portion. ### Claim 16 (depends on 15) The electrode of claim 15, wherein said metal wires are stainless steel wires, said attaching means comprising a moisture impervious substrate to which the tubular conductor is fastened. ### Claim 17 (depends on 15) The electrode of claim 15, including four of said conductors arranged in parallel on said substrate in a quadripolar array for making peripheral plethysmograph measurements, said attaching means fastening said conductors and substrate about a limb of the body with the conductors in an elastically stretched condition.