Medical electrode and release liner configurations facilitating packaged electrode characterization

Abstract

An electrode includes a conductive adhesive layer and a conductive foil layer having a void therein. One such electrode may be mounted in conjunction with another electrode upon a release liner having one or more openings therein to facilitate electrical signal exchange between electrodes. A release liner may include a moisture permeable and/or moisture absorbent membrane. A release liner may alternatively include a conductive backing layer. A release liner may also include an insulating swatch covering an opening. A release liner may be implemented as a foldable sheet, such that multiple electrodes may be mounted upon the same side of the foldable sheet. A medical device to which the mounted electrodes are coupled may characterize the electrical path between the electrodes. The medical device may perform a variety of electrical measurements, including real and/or complex impedance measurements. Based upon one or more measurements, the medical device may provide an indication of electrode condition, fitness for use, and/or an estimated remaining lifetime. An electrode condition indicator, which may form a portion of the medical device, may generate, present, or display electrode condition and/or estimated remaining lifetime information via a visual metaphor, such as a fuel gauge.

1. A release liner comprising:
 a release layer, said release layer having an opening therein; and   one from the group of a moisture permeable membrane and a moisture absorbent membrane, the membrane covering the opening.   
     
     
       2. The release liner of  claim 1 ,
 wherein the membrane comprises paper.   
     
     
       3. The release liner of  claim 1 ,
 wherein the membrane is maintained in a position via attachment to the release layer.   
     
     
       4. A release liner comprising:
 a first release layer; 
 one from the group of a moisture permeable membrane and a moisture absorbent membrane; and 
 a second release layer,
 wherein the first release layer includes an opening therein, and wherein the second release layer includes an opening therein. 
 
 
     
     
       5. The release liner of  claim 4 ,
 wherein the membrane comprises paper. 
 
     
     
       6. An electrode system for a medical device employing an electrode to exchange signals with a subject comprising:
 a conductive adhesive layer; and   a conductive layer affixed to the conductive adhesive layer, the conductive layer having a nonconductive region therein,   wherein the conductive adhesive layer overlays the nonconductive region,   wherein the conductive adhesive layer and the conductive layer comprise a first electrode; and further comprising:   a second conductive adhesive layer;   a second conductive layer affixed to the second conductive adhesive layer, the second conductive layer having a nonconductive region therein, the second conductive adhesive layer overlaying the nonconductive region of the second conductive layer,   wherein the second conductive adhesive layer and the second conductive layer comprise a second electrode; and   a release liner, located between the conductive adhesive layers of the first and second electrodes, the release liner having a a first release layer, one from the group of a moisture permeable membrane and a moisture absorbent membrane, and a second release layer, wherein the first release layer includes an opening therein, and wherein the second release layer includes an opening therein,   and further wherein the conductive adhesive layers of the first and second electrodes are electrically connected in the vicinity of the nonconductive regions.   
     
     
       7. The electrode system of claim 6, wherein the nonconductive regions comprise voids in the conductive layers. 
     
     
       8. The electrode system of claim 6, further comprising:
 a first lead wire electrically coupled to the conductive layer of the first electrode;   a second lead wire electrically coupled to the conductive layer of the second electrode; and   a measurement circuit, located in the medical device, and electrically coupled to the first and second lead wires, and operable to measure an electrical characteristic of the conductive adhesive layers.   
     
     
       9. The electrode system of claim 8, wherein the measurement circuit is operable to measure at least one of a current or impedance of the conductive adhesive layers. 
     
     
       10. The electrode system of claim 6, wherein the low impedance region of the release liner is smaller than the nonconductive regions of the conductive layers. 
     
     
       11. An electrode system for a medical device employing an electrode to exchange signals with a subject comprising:
 a conductive adhesive layer having a lateral dimension and a thickness dimension;   an electrical conductor electrically coupled to the conductive adhesive layer; and   a conductive layer having a lateral dimension and affixed to the conductive adhesive layer with its lateral dimension substantially in parallel with the lateral dimension of the conductive adhesive layer, the conductive layer constraining the passage of current in at least a portion of the shortest current path between the conductive layer and the electrical conductor to be in the lateral dimension of the conductive adhesive layer;   wherein the conductive layer and the affixed conductive adhesive layer comprise a first electrode;   wherein the electrical conductor comprises a second electrode having a conductive layer and an affixed conductive adhesive layer; and   a release liner to which the conductive adhesive layers of the first and second electrodes are attached, the release liner having a first release layer, one from the group of a moisture permeable membrane and a moisture absorbent membrane, and a second release layer, wherein the first release layer includes an opening therein, and wherein the second release layer includes an opening therein to form a low impedance region which electrically couples the conductive adhesive layer of the first electrode to the second electrode.   
     
     
       12. The electrode system of claim 11, wherein the conductive layer of the first electrode has a high impedance region therein;
 wherein the low impedance region of the release liner opposes the high impedance region of the conductive layer across the thickness dimension of the conductive adhesive layer of the first electrode.   
     
     
       13. The electrode system of claim 12, wherein the low impedance region of the release liner is smaller than the high impedance region of the conductive layer. 
     
     
       14. The electrode system of claim 13, wherein the passage of current is constrained to the lateral dimension of the conductive adhesive layer of the first electrode where the high impedance region of the conductive layer opposes the release liner adjacent to the low impedance region of the release liner. 
     
     
       15. An electrode system for a medical device employing an electrode to exchange signals with a subject comprising:
 a release liner having a first release layer, one from the group of a moisture permeable membrane and a moisture absorbent membrane, and a second release layer, wherein the first release layer includes an opening therein, and wherein the second release layer includes an opening therein to form a low impedance region;   a first electrode having a conductive adhesive layer overlaying a surface of a conductive layer, the conductive adhesive layer having a thickness dimension which is orthogonal to the surface of the conductive layer and a lateral dimension, the conductive adhesive layer transporting current between the conductive layer and the low impedance region of the release liner in the lateral dimension of the conductive adhesive layer during a test mode.   
     
     
       16. An electrode system for a medical device employing an electrode to exchange signals with a subject comprising:
 a release liner having a first release layer, one from the group of a moisture permeable membrane and a moisture absorbent membrane, and a second release layer, wherein the first release layer includes an opening therein, and wherein the second release layer includes an opening;   a first electrode attached to the first release layer of the release liner and having a conductive adhesive layer overlaying a conductive layer;   a second electrode attached to the second release layer of the release liner and having a conductive adhesive layer overlaying a conductive layer, the conductive adhesive layer of the second electrode being electrically coupled to the conductive adhesive layer of the first electrode,   wherein the conductive adhesive layer of the first electrode is in contact with the conductive adhesive layer of the second electrode through a low impedance region of the release liner,   wherein the impedance between the conductive layers of the electrodes is outside the expected impedance range of the subject.   
     
     
       17. The electrode system of claim 16, wherein the thickness of the conductive adhesive layer of the first electrode exhibits a first impedance;
 wherein the thickness of the conductive adhesive layer of the second electrode exhibits a second impedance; and   wherein the impedance between the conductive layers of the electrodes is greater than the sum of the first and second impedances.   
     
     
       18. The electrode system of claim 17, wherein the impedance between the conductive layers of the electrodes includes a current path through a conductive adhesive layer which is orthogonal to the thickness dimension of the conductive adhesive layer.