CA1182864A

CA1182864A - Medical electrode construction and method of assembly

Info

Publication number: CA1182864A
Application number: CA000366232A
Authority: CA
Inventors: Rex O. Bare; Earl F. Robinson
Original assignee: CR Bard Inc
Current assignee: CR Bard Inc
Priority date: 1979-12-06
Filing date: 1980-12-05
Publication date: 1985-02-19
Also published as: ES8201421A1; BE886526A; ES8300013A1; GB2075348B; ES505963A0; ES8300014A1; ES8300015A1; ES497491A0; GB2075348A; US4365634A; WO1981001646A1; FR2471198A1; ES505964A0; FR2471198B1; ES505962A0

Abstract

Abstract of the Disclosure There is disclosed an electrode construction of the type including a terminal arrangement and support means for said terminal arrangement, said support means adapted for the transcutaneous application of the electrode to a patient.
The support means may be fabricated from a layer of foam or microporous material, or plural layer employing a combina-tion of both, or from a layer of conductive adhesive. The terminal arrangement may be of single terminal or multi-terminal design, and is provided by a conductive pattern printed on a semi-flexible plastic-like sheet, wherein said pattern is printed with a conductive ink of the type em-ploying a conductive metal, such as silver, in a binder composition. The disclosure also contemplates novel struc-ture for connection of the electrode to a lead wire, as well as several novel, overall designs for the construction of the electrode support means.

Description

~ard Case 14 M¢DICAL ELECTRODE CONSI'R~CTIO~
_ AND METHOD OF ASS~MBLY __ Background of the invention -The present invention relates to electrodes, and more par-ticularly ~o disposable medi.cal electrodes of the type employed in the transcutaneous monitoring of biological or physiological electrical potential associatea with muscular activity.

In recent years, medical science has developed the art of transcutaneous monitoring to a rather high degree and for a variety of purposes. This type of monitoring is used to detect muscular activi~y of the heart muscle by use of electrical apparatus referred to in the art as an electro-cardiograph (ECG) The resulti-ng traces or electrocardio-grams achieved with this procedure provide a diagnostictool which enables the cardiologist to detect neart disease and general defects, etc In addition to cardio-muscular applications, transcutaneous monitoring can be employed to indicate the degree of nerve blockage result-ing due to anesthetization of a patient during surgery.In this regard, one set of electrodes are used to apply a controlled, low voltage potential to a particular muscle nerve, and a second set of electrodes may be used to moni-tor the resulting muscular contractions. These contrac-tions are recorded on a electromyograph ~EMG), with theresulting trace indicating the degree of effectiveness being achieved with the anesthetic.

The electrodes initially developed for ECG or EMG applica-tions were reusable, and referred to as "permanent elec-trodes". These electrodes were of a type which utilized a non-conductive base that was applied to the skin either by means of suction cups or straps, with a metal ~erminal element housed within the non-conductive base and connected to the ECG or EMG apparatus via lead wires. To assure ~ard ~ase 1~

- 2 -proper electrical contact, an electrolytic gel or paste was often employed in conjunction with the metal terminal. In many of these ear:Ly designs, the terminals employed were either pure silver, German silver (pewter) or silver-plated metals or plastics" as it was found that silver provided superior results due to its tendency not to store an elec trical charge. As can be appreciated, these permanent electrodes were rather expensive to manufacture. Also, the permanent type of electrode required that it be cleaned and disinfected after each use and before reuse. This procedure was time cons~ning such that disposable or single use elec-trodes were soon developed which out of necessity had to be of an inexpensive construction. Examples of several types of disposable electrodes can be found in United States Patents Nos. 3,989,035 and 3,~05,769.

These disposable electrodes typically included a support structure for the metal terminal element in the form of a relatively thin adhesively coated layer or disc of cellular foam, or in some applications, a thin microporous tape is used. The requisite metal terminal was provided by the em-ployment of a two piece snap fastener engaged either di-rectly through the foam or tape layer, or in some instances, the support arrangement was apertured with a second layer of impervious material overlying the aperture, and the snap fastener carried by said second layer. In conjunction with the snap fastener, a porous matrix was applied which in the case of a pregelled electrode, was impregnated with a quan~
tity of gel, and a cover arrangement of some sort placed over both the gelled matrix and the adhesively coated sur-face of the support arrangement.

The snap fasteners which provide the electrical terminals for these prior art electrodes have proven to be both expensive, and a source contributing to inconsistent per~
formance of the el.ectrode. In this regard, the snap fastener ~ald ~ase l4 component associated with the gelled matrix is of a two part construction, with an inner element and an outer element, and is e:ither totally or partially constructed of silver, stainless steel, nickel, or a silver-coated plastic or metal component. As such, the snap fastener is a rela-tively expensive component of the overall electrode con-struction, however, this design is tolerated as the snap fasteners lend themselves to the high speed automated con-struction of the electrode, necessary to achieve low cost production.

Further, it has been found that in use the snap fast~ner contributes significantly to the often erratic performance of the electrode. In this regard, the electrode is con-nected to the ECG apparatus by means of a lead wire havinga female type snap connector on the end thereof engaged over the post or male component of the snap fastener. This connection provides considerable mass with respect to the remainder of elect.rode, such that patient movement results in alterations in the disposition of the electrode terminal with respect to the skin of the patient. More specifically, any movement producing tension in the lead wires would tend to pull the electrode terminal away from the patient's skin, whereas if the pat:ient should happen to roll over, the pro-truding nature of the snap fastener would cause the metalterminal to be forced inwardly toward the skin, all of which contributing to the production of rather inconsistent ECG
traces. As a further problem, electrodes with projecting snap fastener type termlnal means do not lend themselves to stacking, and must: be handled carefully during shipping and storage. In this regard, any rough handling or compressing together of the electrodes will tend to squeeze the gel from the gelled matrix.

The electrode system and electrode design of the present invention, as illustrated and described hereinafter, eli-minates the need ~or the snap fastener as a component of Bard Case 14 the Lerminal means. Further, the present design achieves elimination of the snap fastener component, in a manner which results in improv~d performance, in that stability ofthe terminal position vis-a-vis the patient's skin is attained. Still further, this improved electrode design lends itself readily to automated assembly, and is usable with an overall system that envisions further improvements in the manner of connecting the electrode to the lead wire extending from the ECG or EMG apparatus.
More specifically, the electrode d~signs of the present invention utilizes a terminal arrangement provided by a pattern printed with conductive ink on a sheet of stable, semi-flexible, plastic-like material. The term "semi-flexible" is used with respPct to the terminal bearingsheet for purposes of description, in that said sheet must be capable of slight flexure, yet must be relatively stiff or rigid, so as to resist any stretching or perma-nent deformation during use. Should stretching or defor-mation occur, this would result in fracture or interrup-tion in the continuity of the printed conductive pattern, and thereby destroy its effectiveness as a conductive ele-ment. It has been found, that a relatively thin, clear, plastic-like film such as that sold under the trade mark "MYLAR", is satisfactory for this purpose.

Looking to the overall basic construction, the electrode design of the present invention utilizes a support arrange-ment or layer which may be fabricated from a relatively thick, closed cell foam material of various types widely known in the trade, with one side of the foam support layer coated with a standard medical grade adhesive for securing or adhering the electrode to the skin of the patient. The support layer is apertured and the semi-

3~ flexible plastic-like terminal bearing sheet is affixed to the side of the support layer opposite that upon which the adhesive is appl;ed. In this regard, ~he plastic-like sheet is positioned with the side having the conductive i:
, .. .~ ~

Bard Case 14 ink pattern thereon facing the support layer, with the terminal portion of said conductive ink pattern aligned with the associated aperture. Preferably, the conductive ink pattern also includes a conductor portion extending away from the area of the aperture, to which a lead wire is connected. The aperture in the support layer and the overlying plastic-like sheet material serve to define a well or chamber in which is disposed a porous or reticu-lated matrix, such as may be provided by a sponge-like plastic-like material, many versions of which are well known in the art. The porous matrix, or 'Igel pad" as it is often termed, i5 impregnated with a quantity of electrolytic gel, ,also of known formulation. ~ suitable easily removable cover arrangement overlies the adhesive coating on the support layer and the gel pad to prevent deterioration of the gel during storage.

The use of the sem:i-flexible terminal bearing sheet provides a relatively low mass terminal arrang~ment, which in use achieves a constant, stable positioning of the terminal means with respect to the skin of the patient.
That is to say~ the terminal portion will be spaced from the patient's skin, with the intermediate space filled by the electrolyte gel and the gel impregnated pad or matrix. This spacing is referred to in the art, and here-inafter, as the "gel colum~L". More specifically, due to the low mass of the terminal arrangement provided by the conductive pattern on the sheet and the manner of connec-tion of the electrode to the ECG apparatus, any patient motion, rclling over of the patient, or any tension on the ECG lead wires will not affect gel column stability to a great extent. Thus, the present design provides an inexpensive, disposable electrode capable of attainment of a consistent, highly accurate trace from the ECG
apparatus.

As mentioned above, the manner of connecting the electrode to the ECG apparatus lead wire as contemplated by the Bard Case 14 ~ 3 present invention is also of significance, and contributes to the overall effectiveness Oc the electrode system. In both the single terminal and multi-terminal designs illus-trated and to be discussed, the lead wires are connected S at areas remot~ from t~e terminal portion. In one pre-ferred, disclosed embodiment, ~he plastic-like, semi-flexible terminal bearing sheet includes a tab segment which is free of connection or adherence to the underlying support layer. The conductive pattern printed on said semi-flexible plastic-like sheet includes a conductor portion extending along this tab segmen~, such that the tab may be inserted within an electrical connector affixed to the end of an ECG lead wire. As will be discussed, the construction of the connector and the tab segment are such that they serve to isolate any stress or strain from the area of the terminal portion, which might affect tne gel column.

A further aspect of the present invention and one most particularly applicable with respect to the single terminal electrode design dlscussed above, is the manner by which the design lends itself to automated fabrication. In and of itself, automated fabrication of an electrode is not novel, one such method of being illustrated and described in the aforementioned United Statés Letters Patent No.
3,805,769. The present invention, however, contemplates a novel method of assembly that is particularly advantageous with respect to the single terminal design as disclosed herein and other existing or possible future electrode designs.

In addition to the single terminal type of construction discussed above, the invention also contemplates various forms of multi-terminal assemblies, one of which is illustrated in the drawings and discussed in detail hereinafter. With the illustrated, contemplated design, a plastic-like, semi-flexible terminal bearing sheet is tl employed to join toge-ther two simil~r shaped suppo~t layers, each having one or more apertures thereln with a terminal element on said sheet aligned with each aperture. With this arrangement, the semi-flexible sheet not only carries the terminal means, but acts as a hinge or connection between the respective support layer to provide an integral yet articulated assemblage. As will become apparen-t from the discussion to follow, this design is extremely advantageous with regard to both use of the multi-terminal assembly, its manu-facture, and packaging thereof.
Thus, in accordance with a broad aspect of the invention, there is provided a disposable medical electrical construction of the type adapted to be adhered to the s]cin of a patient for opera-tive connection to electrical apparatus, said electrode construc-tion comprising: a support arrangement for an electrical terminal, said support arrangement having aperture means formed therein, and an adhesive coating on a surface thereof for applying the electrode construction to the skin of a patient; a semi-flexible plastic~like sheet secured to said support arrangement and overlying, at least partially, said aperture means in spaced relation to said adhesively coated surface on the support arrangement; terminal means on said plastic-like, semi-flexible sheet adapted for use in establishing an electrical connection to the electrical apparatus, said terminal means being provided by a thin pattern of conductive ink printed on the surface of said sheet in the area thereof overlying said aper-ture, said pattern including a terminal portion aligned with said aperture meansl said semi-flexible plastic-like sheet further includ-ing a tab member extending from the segment thereof having the ter-minal portion of the ink pattern thereon, -the distal end of the -tab member being free from attachment to said support arrangement, and said thin conductive ink pattern extending from -the -terminal portion along the tab member to define a conductive portion, such that said tab member may be inserted into a suitable electrical connector and the conductive portion of said ink pattern brought into contact with terminal means carried by said connector.
The present invention is possessed of numerous features and advantagesl in addition to those discussed specifically above.
It is believed that these features and advantages will become appar-ent Erom the detailed description of the invention which follows, taken in conjunction with the accompanying drawinys which form a part of said description.
BRIEF DESCRIPTION OF THE DRAWINGS
, . _ .~_ FIGURE 1 is an exploded perspective view of a single term-inal electrode, including the cover member;
FIGURE 2 is an assembled view of the electrode of Figure 1, with a lead wire connector attached to the electrode assemblage;
FIGURE 3 is a plan view of the semi-flexible, plastic-like terminal bearing sheet, with the adhesive layer applied thereto;
FIGURE 4 is an exploded sectional view of the electrode of Figure 3;

- 7a -Bard Case 14 ~ &

FIGURE 5 is a sectional view taken along the line 5-5 of Figure 3;-FIGURE 6 is a partial sectional view of one form of con-5 nector arrangement to be employed with the electrode assemblage of Figures 1 and 2 and the electrode tab seg-ment engaged therewith;

FIGURE 7 is a longitudinal sectional view of the con-10 nector of Figure 6 with the tab portion of the electrode disengaged;

FIGURE 8 is a partial sectional view of an alternate form of connector to that as shown in FI&URE 6;
FIGURE 9 is a longitudinal, partial sectional view of the connector form of Figure 8 J with the tab segment of the electrode disengaged;

20 FIGURE 10 is an exploded perspective of an alternate form of electrode assemblage constructed in accordance with the invention;

FIGURE 11 is an exploded sectional view of the electrode 25 as illustrated in Figure 10;

FIGURE 12 is a sectional view of the electrode embodiment in Figure lO adhered to the skin of a patient;

30 FIGURE 13 is a schematic, diagrammatic view illustrating the respective steps of a method of constructing the electrode assemblage of Figures 1-5;

FIGURE 14 is a partial schematic view illustrating 35 several of the steps in the method of assembly as illustrated in Figure 13;

Bard Case 14 ~ 2 g FIGURE lS is a plan view of a multi-terminal electrode, constructed in accordance with the present invention, with an upper foam layer removed from the left hand portion of the assemblage, as viewed;

FIGURE 16 is a view of the adhesively coated surface of the electrode of Figure 15, illustrating the reverse side of said electrode and the application of a deacti-vating compound to certain portions of said adhesively 10 coated surface;

FIGURE 17 is a partial sectional view of the connector portion of the electrode of Figure 15J taken along the lines 17-17 of sa;d Figure 15;
FIGURE 18 is a partial sectional view through one of the terminal portions and the gel pad of the electrode assemblage of Figure 15 taken along ~he line 18-18;

20 FIGURE 19 is a partial, exploded view of the electrode construction as illustrated in Figure 15;

FIGU~E 20 is a partial plan view of an extension portion on the semi~flexible plastic sheet at which a terminal 25 portion of the conductive ink pattern is shown;

FIGURE 21 is a perspective view of the manner in which the electrode assemblage of Figure 15 is prepared for packaging;

30 FIGURE 22 is a pers~pective view illustrating the electrode assemblage in the pre-packaged construction;

FIGURE 23 is a sectional view taken along the line 23-23 of Figure 22;
FIGURE 24 is an exploded perspective view of still another type or form of electrode design in accordance with the invention;

~ard C`ase 14 FIGURE 25 is a sectional view along the line 25-25 of Figure 24;

FIGURE 26 is a perspective view similar to Figure 24, and illustrating an alternate form of connection of the electrode to a leacl wire;

FIGURE 27 is a sectional view taken through a completed electrode of Figure 26, generally along the line 26-26;

FIGURE 28 is a plan view of a multi-terminal electrode constructed in accordance with the design of Figure 24, and having pre-attached lead wires; and FIGURE 29 is a sectional view taken along the line 29-29 of Figure 28, and illustrating the crimp-type connection for the lead wires.

Bard Case 14 .D9L

Detailed Descr ~__on Of The Drawin~s The present invention is possessed of numerous aspects, and four distlnct but related embodiments of electrode constructions are :illustrated in the drawings. The first embodiment is encompassed by Figures 1-9, and relates to a single terminal electrode assemblage designated generally 30 which is employed with a lead wire and connec-tor assembly 32 and utilizes the relatively thick, foam type 10 support arrangement or layer. Figures 10-12 illustrate an alternate form of a single terminal design 80 which is adapted for use wit:h the assembly 32 (not shown in said figures). This alt:ernate design 80 employs a support arrangement which i.s comprised of a relatively thick foam 15 ring to provide the desired gel column, and a thinner, more extensive microporous layer, which microporous layer includes the adhesive material employed to affix the electrode to the skin of a patient. In Figures ].3 and 14 there is shown rather schematically, a method of 20 assemblage for the electrode construction 30 of Figures 1-5. A multi-terminal electrode construction in accor-dance with the present invention is shown in Figures 15-23, and designated generally 120. Still a further type of electrode construction is shown in Figures 24-29, wherein 25 the support arrangement is provided by a conductive ad-hesive layer, thereby enabling elimination of the foam and/or microporous layers as well as the porous matrix.
In the discussion that follows, even though common com-ponents of the various emodiments will be designated by 30 similar terms, for purposes of description and understand~
ing different reference characters will be utilized. As a further matter, since certain of the features of the various electrode designs are embodied in extremely thin layers or components, certain of these have been exagge-35 rated dimensionally in the drawings in order to facili-tate description and discussion.

P~ard Case :L4 ~ ~ ~Z~6~

Looking now to Figures 1-5, the construction of a single terminal electrode assemblage 30 is shown and will be considered in detail. In this regard, the term "elec-5 trode construction" is used collectively to indicatethe assemblage as actually applied to the skin of a patient, as well as said assemblage in conjunction with a release liner type cover 34. More specifically, the electrode construction 30 includes a base or support 10 arrangement 3G in the form of a layer of foam-like plastic material such as polyethylene foam which material is preferably of a non-reticulated or closed cellular con-struction to prevent absorption of the gel material.
The base or support layer 36 includes a generally central 15 aperture 38 extendi.ng completely through the layer 36.
One surface of the support arrangement provided by the foam layer 36 includes a coating 40 of an adhesive material (Figs. 4 and 5), which adhesi~e material may be any of a number of commercially available medical grade adhesives 20 presently in use with prior art types of electrodes, and thereby well known in the art.

Affixed to the surface of the support layer 36 approximate said adhesively coated surface is a sheet of semi-flexible 25 plastic-like material 42 which is secured in overlying relation with respect to the aperture 38 by means of an extremely thin ring--like component or layer 43 having adhesively coated surfaces 45 and 47 on opposite sides ~hereof; said component bei.ng termed hereinafter "a 30 double sided adhesively coated annu~ The assemblage of the sheet of plastic-like material 42 to the support layer 36 in effect closes on~ end of the aperture 38 and serves to cooperate therewith to define a well or chamber 38 for a purpose to be discussed. The sheet 42 is re-35 ferred to as constructed of a "semi-flexible, plastic-like material" for purposes of description and general Bard Case 14 definition. In this regardJ it is to be understood that there exists numerous types of materials from which the sheet 4~ can be constructed; these materials, however, must possess certa:in properties in that it is important that they be relat:ively thin and slightly flexible, yet they must not be subject to stretching or permanent deformation during normal use or during assembly. A
material which has proven satisfactory for use in con-struction of the sheet 42 is a clear plastic material 10 sold in sheet form under the trademark "MYLAR".

Further, the semi-flexible, plastic-like sheet 42 has terminal means thereon in the form of a conductive ink pattern 44 printed directly on one surface of said sheet.
15 Due to the clear nature of the preferred material for the semi-flexible sheet 42, this pat~ern is visible from the opposite surface of said sheet. The pattern 44 of the disclosed embodiment 30 includes a generally circular terminal portion 46 and a conductor portion 48. As can 20 best be seen in Figure 1, the conductor portion 48 ex-tendsfrom the terminal portion 46 along a tab s~gment 50 of said sheet 42, whi h tab segment includes a pair of notches 52 for the purpose to be discussed.

25 Disposed in the well 38' is a porous matrix or gel pad 54, preferably formed of an open cellular sponge like plastic material. Keeping in mind the fact that the electrode 30 is of the pregelled type, there is also included a quantity of electrolytic gel (no reference 30 character), which impregnates the matrix 54 and effec-tively fills the well 38' provided by the aperture 38.
This electrolytic gel can be any of various commercially available products, as for example sodium chloride in agar. In the event that the electrode is not to be pre-35 gelled, the emplo~nent of said electrolytic gel may bedispensed with, without variation in the overall con-s~ruction.

Bard Case 14 - 13 ~

With reference to Figures 3, 4 and 5, it should be noted that the double sided adhesive annulus 43 includes an aperture 56 which is smaller in diameter than the aperture 38 in foam layer 36, and upon assembly,surrounds the terminal portion 46 without overlying said terminal portion, Figure 3. As such, when the semi-flexible sheet 42 is mountecl ~o the support arrangemen~, 36, a portion47a of the adhes:ive coating 47 on said ring 43 is exposed interiorly of the aperture 38, as bes~ seen 10 in Figure 13. Thus, upon disposition of the gel matrix 54'in the aperture 38, as shown in Fi~ure 5, said matrix 54 is adhered to the semi-flexible plastic-like sheet 42 by means of the exposed adhesive portion 47a.

15 To complete the electrodeconstruction 30, the cover 34 is applied to the adhesively coated surface 40 of the foam layer 36, said cover 34 overlying said surface 40, as well as the gelled matrix 54. The cover 34 is pre-ferably constructed of a high density polyethylene having 20 a release coating on the surface thereof engaged against the adhesively coated surface 40 of the foam layer 36.
As such, when it is desired to utilize the electrode,the cover 34 can be removed easily and ~he electrodecon-struction applied to the skin of the patient, with the 25 adhesive surface 40 providing the means for affixing and maintaining the electrode in proper pOSitiOII.

Returning to the semi-flexible sheet 42 with the con-ductive ink pattern 4~ thereon, the ink utilized is 30 applied by conventional printing techniques in an ex-tremely thin layer, .001-.010". As such, patterns other than the pattern 44 as specifically illustrated may be easily employed. Ink of the general type con-templated is comprised of a composition of a conductive 35 metal, carried within a binder. It is preferred that the ink utilized employ silver as the conductive com ponent. Ink of this nature can be obtained from Bard Case 14 n~mlerous sources, one such source being E.I. DuPont DeNemours and Company. The particular compositions available from this company lnclude silver in a pro-prietary binder system specifically designed to adhere ~o a plastic~like material such as "MYLAR" without peel-ing or cracking during flexure of said material. As such, it carl be appreciated that the material used for the plastic-like sheet or subs~ra~e 42 must be sufficiently rigid to resist any stretching or deformation during 10 normal use or assembly. Should stretching occur, the danger exists that the ink pa~tern will be fractured, destroying its continuity and the ability of said conduc-tive pattern 44 to function as an electrical terminal arrangement. As an additional matter it is also preferred 15 that the sur~ace of the terminal portion 46 of said conductive silver ink pattern be chlorided to produce a thin silver chloride coating, which has proven to provide superior performance This process of chlorid-ing can be accomplished in any one of several known 20 manners, such as electrodeposition or by reaction with chlorine gas.

An additional feature of the invention that should be noted, is the construction of the sheet 42 with 25 its tab portion 50, and the location of the adhe-sively coated annulus 43 thereon, as best seen in Figure 3. In this regard, the sheet 42 is fabri-cated and the conductive ink pattern 44 is printed thereon prior to application of the adhesive annulus 30 43. The adhesive annulus 43 includes an aperture 56, such that upon its application to a surface of the semi-flexible sheet 42, it will encompass the termi-nal portion 46 of the conductive ink pattern 44, but preferably does not cover or overlie said terminal 35 portion 46. As shown in Figure 3, the adhesively coated annulus extends only to the general periphery Ba~d Case 14 6~

of the main segment of the sheet 42, and does not ex-~end along the tab segment 50, thus overlying only partially the conductor Portion 48. When the sheet 42 is assembled to the su~ort layer 36 only the main segment thereof is adhered to the u~er surfacP of said sup~ort layer 36, the ~ab segment 50 re~aining free and unsecured thereto. In addition to providing the surface 47a to which the porous matrix 54 is attached, and securing the sheet 42 to the support 10 layer 36, the annulus 43 also serves to seal the gel matrix chamber 38' and prevent migration or leakage of the gel along the tab se~ment 50. As such, tak.ing into account the non-~orous nature of the foam layer 36, the sheet 42 and the release liner 34, it can 15 be seen that there is provided a substantially her-metically sealed chambers 38' for the gel which serves to resist deterioration and drying out of the gel during storage nri.or to ,use.

20 l'he free or unsecured nature o the tah segment 50 enables the electrode to be connected to ECG ap~aratus by means of a lead wire arran~ement 32 having an elec-trical connector 60. As seen in Figures 2 and 5, the tab segment 50 is engaged with or received within 25 the electrical connector 60 and a connection is made with the conductor nortion 48 on said tab segment 50.
Details of two preferred or anticipated designs for connectors 60 are illustrated in Fîgures 6-9 and will be discussed more fullv hereinafter. While these 30 specific designs are believed to be novel ~er se, it is also believed that the general conce~t utilizing a free tab se,~ment and a ~rinted ink conductor segment thereon to achieve electrical connection with ~he lead wire arran~ement 32 is a novel concent, Looklng to Figures 6 and 7, there is illustrated a first form or tvne of electrode connector 60 which may be Bard Case 14 f,~

em~loyed in the electrode system of the presen~ in~ention.
The connector 60 includes a housing 62 having an open end 63 leading to the interior thereof, wherein there is mounted a spring-tyne clip terminal 64 having upper and lower arms 65 and 66, resnectively A lead wire 68 passes inwardly of the housing with the housing being crimped to enga~e said lead wire at 69, said wire 68 being con- -nected to the tenninal 64. At the forward entry portion of the open end of the housing 62 there is provided a 10 nair of spaced, ramp shaped projections 70. The pro-jections 70 are s:ized and spaced apart such that u~on disnosition of the tab se~ment 50 within the housing, the projections 7() will be receive~ within the notches 52 of said tab segment, The tab segment 50 is re-15 ceived between the snrin~,-like arms 65 and 66 with the upner spring arm 65 forcing the tab segment down-wardly to maintain the tab seg~ent engaged over the nrojections 70. Accordingly, if any tension is appli~d to the lead wire 68, the engagement of the projections 70 20 in the notches 52 will serve to resist inadver~en~ dis-connection, and also function to achieve a degree of strain relief, isolating any stress from the area of the electrode terminal portion 46, It can be appreciated further, the metal terminal 64 is designed to engage 25 the nrinted ink conductor ortion 48 on the tab seg-ment 50, thereby effecting an electrical connection.
Further, since said metal terminal 64 includes a pair of opposed arms 65 and 66, inverting of the connector 60 upon assembly would not preclude attainment of a `30 pro~er electrical connection.

Figures 8 and 9 illustrate a modified ty~e of connector 60' for use with a tab segment 50 having an aperture 72 formed thereon. In this regard, the connector 35 h~us,ing 62' has a nrojection or nost 74 formed thereon, and siæed for dispostion in said aperture 72. Accordin~ly, Bard Case 14 in the assembled or en~a~ed position, as shown in Figure 8, the spring terminal 64' will engage the printed ink con-ductor portion 48 to effect the desired electrical con-nection, and also ~aintain the tab segment 50 engaged over the post 74.

A modified form of electrode construction in accor-dance with the present invention isillustrated in Fi~,ures 10-12, and designated generally 80. The elec-10 trode embodiment 80 differs from the electrode con-struction 30 in that the supPort arran~ement includes a relatively thick ring 82 which may be made of a foam material or a rigid plastic, and a section of microporous ta~e material 84 having an adhesive 15 coating 86 on one surface thereof for adhering the electrode to the skin of a patient. The rin~ 82 includes a cen~ral aperture 83, while the section of microporous tape 84 has an anerture 85 of a somewhat smaller dimension, for a purpose to be discussed 20 ~ore fully hereina:E~er, In certain applications where an electrode wil:L be in place for an extended period of time, use of a m:icroporous ta~e layer prevents derma-talogical problems as it allows air to reach the patient's skin surface, Suitable types of medical 25 grade of micro~orous tape are available and well known in the art, one being sold under the trade ,mark "MICP.OPORE" by the 3~ Company, and another by Johnson &
Johnson under the trademark "DE~IICIL".

30 The re~aining construction of the electrode 80 is somewhat similar to that of the electrode 3Q discussed above, in that the ter~inal arrange~.ent is provided by a semiflexible plastic-like sheet 42 of identical construction to that previously detailed, said sheet 35 including a tab portion 50, a pattern 44 printed thereon with the conductivP ink and definin~, a terminal portion 46 and a conductor ortion 48. A double-sided .

Bard Case 14 6 ~

adhesive annulus 43 is used to affix the semi-flexible sheet 42 to the upper surface of the ring 82, with the tab 50 re~aining free of any connection thereto.
The lower surface of the ring 82 as mentioned previously, includes an adhesive la~er 86, which affixes the ring 82 to the upper surface of the micrQ-norous disc 84. The a~lication of the semi-flexible Plastic-like sheet 42 to the ring 82 serves to define a well 83 in which a ~orous matrix 54 is disPosed. As was the case with 10 the electrode 30, the double-sided adhesive annulus 43 has a central aperture somewhat smaller than the aperture 83 of the rinF" such that a ~ortion of the adhesive will be exnosed with the norous matrix 54 secured thereto.
A cover member 34 is ~rovided, having an upPer sur-15 face 34' uPon which there is provided a release linercoat~n~ which enables the cover 34 to be removed easily immediately prior to application of the electrode to the skin of a pati.ent.

20 In Figure 12, the assembled electrode construction 80 is shown mounted to the skin 90 of a patient. It can be seen that the relatively thick ring 82 serves to nrovide a substantial well 83' for the gel pad 54, which also defines the height of the gel column. Further, 25 it should be noted that the aperture 85 in the mi.cro-porous sunport arrangement component 84 is of slightly smaller dimension than the gel matrix 54, so as to over-~lap slightly said matrix in the assembled condition.
This overlap~ing design serves to further retain the 30 gel matrix 54 in Position, and prev~nt migration of the - ~-gel along the interface with the patient's skin 90.

Attention is now invited to Fi~ures 13 and 14, wherein a ~referred method of manufacture of the electrode con-35 struction 30 is shown, the illustration thereindepicting the successive stens of said methods in Bard Case 14 somewhat sche~atic fashion. Initially, an elongate strip 100 of foam materi.al 36 in roll form is nrovided, with said stri.p 100 having a fi.rst release liner 102 covering the adhesive surfaces 40 thereon.
The strip materia:L lO0 is oriented for feeding to a first station I w-Lth the release liner 102 facing up-wardly. At the s~ation I the aper~ures 38 are formed in the striP 100 by a die or punch 104 at spaced successive locations along the strip. At a separate lO sub-station II, the double-sided adhesively coated annulus or ring 43 is applied to the sheet of semi-flexible plastic-like material 42, to attain,a preass~mbled componen~ as was illustrated and discussed with re-spect to Figure 3. Prior to the application of the 15 annulus 43, to the semi-flexible sheet 42, the printed ink conductor pattern 44 is applied to a sec~ion of ~lastic-like sheet material by a conventional print-ing process (not shown) and the sheet material die cut or otherwise formed to the desired shape for the 20 sheet 42.

Next, the preassembled terminal bearing sheet 42 and adhesive annulus 43 are affixed to the undersurface of the strip 100 at station III. With reference to 25 Figure 14, the resulting assembly is illustrated in the left hand portion of said Figure 14, as vie~ed, which illustrates the lower surface of the strip 100 at station.III. In this regard~ it can be seen that the semi-flexible clear sheet 42 is positioned such that ' 30 the terminal portion 46 of the conductive pattern 44 is aligned with the aperture 38. Looking now to the cen-tral portion of Figure 14, the strip 100 has been rotated 180, such that the upper surface carrying the first release liner 10~ is the facing surface, It .' 35 can be seen that a portion 47a of the adhesive am~ulus 43 extends inwardly of the aperture 38 and is disposed in surrounding relationship tothe terminal portion 46.

Bard Case 14 This is the condi~ion of the partially assembled electrode construction, as it is presented to station IV.

At station IV, a ~recut porous ~latr~x 54 is supplied S and disposed within the anerture 38, this results in the matrix adhering to the adhesive portion of 47a.
This step is also illustrated in thecentral portion of Figure 14.

10 The strip 100 next passes to the station V, wherein a quantity of el.ectrolytic gel is injected into said matrix, which gel imPregnates the matrix 54 and fills the well 38'. In this regard, a dispenser 106 will meter out a pre-determined quantity of the gel to 15 prevent over filling of the gel chamber.

The strip 100 ~hen passes to station VI, at which the anertured, first release liner 102 is rem.oved and discarded as waste, As can be seen, the al~ertured 20 release liner 102 is coiled for easy disposition, as illustrated 108. The s~rip 100 with the partially assembled electrode thereon next passes to the station VII, at which a second rel~ase liner 34 is applied. The second release liner 34 is preferably a hig,h density 25 polyethylene sheet with a release liner coating 34' thereon, which material ultimately forms the cover for the pre~,elled electrode 30. In this regard, the second release liner material 34 is in roll form 110, and is applied to the~ strip 100 by a roller 112.
As the strip 100 passes from the station VII, the basic construction for the electrode 30 is complete.
At station VIII, a die cutter or Punch 114 severs the co~pleted electrode construction 30 from the strip 100.
35 The remaining portion of the strip 100 thus becomes waste and can be easily discarded, as the adhesively coated surfaces thereon remains covered by the waste Bard Case 14 portion of the release liner 34.

Looking to Figures 15-23, there is illustrated a multi-terminal electrode, designated ~enerally 120, and con-structed in accordance with the present invention.Multi-terminal electrode constructions of this nature ~reoften referred to in the art as "back pads", in that they are ~ffixed to the patient's back to pro-vide monitoring during chest or abdominal surgery and 10 during recovery thereafter, wherein it would be imprac-tical to utilize chest mounted electrodes. Accordingly, while the multi-terminal electrode illustrated is of the "back p2d" type, it is to be kept in mind that other types of multi-terrninal electrodes such as used ir.
l~ muscle stimulation, electromygographic monitoring or pain therapy may also be constructed in accordance with this lnvention; as such with respect to multi-terminal designs, the embocliment of Figure 15 to be discussed is merely illustrative of one preferred type, and the 20 invention is not l.imited thereto.

Looking now to Figures 15 and 19, the multi-terminal electrode construction 120 contemplates employment of a preconnected lead wire arrangement 122, including a 25 plurality of separate lead wires 123. A further point to be kept in mind for better understanding of the dis-cussion to follow, is that the electrode 120 as sho~n in Figure 15 has a sheet-like component or layer re-moved from the left-hand portion as viewed for purposes 30 of illustration.

More specifically, the electrode 122 is comprised of a support arrangement provided by a pair of similarly shaped sections of relatively thick foam material 124.
35 As was the case with the previously discussed elec-trodes, employment of a closed cellular type foam is preferred, however, any one of a number of various con~nercially available foam materials may be utilized.

Bard Case 14 EaGh section of foam material 124 includes a pair of spaced apertures 126 formed therein. A singular _ section or sheet of semi-flexible, plastic-like material 128 is proviaed, said sheet being mounted to each of the foam sections 124 and in effect interconnecting said sections 124 by bridging the space or joint therebetween.
The semi-flexible sheet 128 is preferably constructed of a plas~ic-like material of the same type as discussed with respect to electrodes 30 and 80, that is the term 10 being "semi-flegible" being used to designate a ~ype of material, such as "MYLAR", which will 1ex slightly, but will not stretch or permanently deform during normal use, assembly or storage. Said semi-flexible plastic-like sheet 128 which will be discussed in 15 greater detail hereinafter, is initially affixed to the foam sections 124 by a partial adhesive coating on the upper surfaces of the foam sections 124 in ~he areas 130, as indica~ed. To complete mounting of the sheet 128, a second relatively thin foam layer or shee~
20 132 is employed w~lich has an adhesive coating on the under surface thereof. Upon assembly of said second sheet 132, as i:Llustrated in the right hand portion of Figure 15, said sheet 132 overlies the semi-flexible plastic-like sheet 128 and is secured to both said 25 sheet 128 and the upper surface of the foam layer 124 by said adhesive coating. It should be noted that while it is preferred that the layer or sheet 132 be o~ a foam or cellular material,other suitable materials may be employed.

30 The specific construction of the semi-flexible, plastic-like section`or sheet 128 will now be considered. In this rega~d, the sheet 128 will be discussed primarily with the left hand portion of Figure 15 and Figure 19, lt being understood that the right hand portion of said shee~ is 35 essentially identical, being a mlrror image of that as illustrated. Further, with regard to Figure 19, which ~s an exploded view of the electrode construction 120, Bard Case 14 ~ 23 -the left hand portion of said sheet 128 can be viewed in somewhat greater detail.

The sheet 128 includes a plurality of arm sections or extensi.ons 136 eminating from a base or central section lS0, each of which terminates in generally circular portion 138. Each of the respective circular portions 138 includes an aperLure 140 formed therein, as is best illustrated in Figure 20. A plurality of 10 individual terminal means corresponding in number to the aper~ures 126 in ~he sheet 124 are provided on the semi-flexible sheet 128. The terminal means in the preferred form of the invention are provided by four individual patterns 144, printed on the underside of 15 the semi-flexible sheet 128 with a conductive ink of the same general type and in the same manner as dis-cussed previously. Each pattern 144 includes a termi-nal por~ion 146 and an elongate conductor portion 148.
As best shown in Figure 20, the terminal portion 146 20 of the illustrated embodiment is of a ring-like configu-ration, encircl~ng the aperture 140, with the conductor portion 148 extending along the arm or extension 136.
The respective conductor portions 148 on each half of ~he sheet 136 extend in opposite direc~ions, and ter-25 minate ad~acent to each other on the base or centralsegment 150 of said sheet. The lead wire arrangement 122 is affixed to the base segment 150 and electrical contact with the conductor portions 148 is attained in a manner which will be discussed more fully herein-30 after with respect to Figure 17.

Completing the basic electrode construction 120 are aplurality of porous matrix members 154 which are engaged in the-apertures 126, as best shown in Figure 35 18. With reference to said Figures18 and also Figure 15, it should be noted that the circular end portion 138 on the respecti.ve extensions 136 are of a diameter Bard Case 14 slightly less than that of the openings 126. Accordingly, when the semi-flexible plastlc-like sheet 128 is mounted in position as shown in Figure 15, the circular end seg- ~' ments 138 overliethe apertures 126 only par~ially. Fur~
ther, taking into account the presence of the opening 140 in said circular end portions 138, i~ can be appre-ciated that when the second, relatively thin sheet of foam material 132 is applied over the semi~flexible plastic-like shee~ 128, portions of the adhesive coating 10 on said sheet 138 remained exposed, interiorly of the aperture 126. Thus, upon disposi~ion of the matrix 154 wi~h the aperture 126, said matrix will be adhered to the exposed adhesive portions, as is shown in Figure 18. Thus, the respective matrixes are maintained in 15 operative association with the terminal portions 146 carried on the circular end segments 138 of the pro-jection 136.

Directing attention to Figure 17, the manner of con-20 necting the lead wire arrangement 122 to the semi flexible plastic-like sheet 128 is illustrated. In this regard, a suitable crimp-type terminal connector 162 is included on the ends of the individual lead wires 123, the crimp-type terminal being engaged through 25 the upper surface of the semi-flexible plastic-like sheet 120 at location 160, and bent over to effect firm electrical contact with the conductor portion 148 on the under surface of said sheet. The rela-tively ~hin foam like sheet 132 is engaged over the 30 terminal connections 162, and is adhered in firm engagement to the plastic-like sheet about the area of said terminal connection 162, such that the en-gagement of said sheet with the terminal connection -~ - and its associated lead wire 123 serve to provide a = - -- 35 measure of strain~d relief. ~s such any tension applied to the lead wires 123 will be taken up, at Bard Case 14 _ ~5 _ least partially, by the engagement of the flexible sheet 132 with the lead wire 123.
~, In Fi~ure 16, the under surface of the electrode 120 is shown with said electrode in the fully open condi-tion. In this regard, the under surface of the respec-tive support layers or sheets 124 is coated with a con-ventional medical grade adhesive for attachment of the electrode to the skin of the patient. Since the 10 extent of the adhesive on the under surface is rather large, and further since it is not always desirable nor necessary to have the entire surface area of the electrode in adhesive contact with a patien~'s skin, a portion of adhesive is deactivated to avoid derma-15 tological problems which may occur after extendedperiods of u6e of the elec~rode or back pad 120. In this regard, a medical grade silicone coating, as designated generally 164, is applied to the central area of each of support arrangement 124, as indicated.
20 This coating in effect deactivates the adhesive in said central area, with the adhesive on the remaining portion, ~he areas surrounding the apertures 126 and gel pads ~54, remain active and capable of effecting attachment of ~.he electrode.
As was mentioned previously, the support arrangement for the preferrecL design utilizes a pair of separate, similarly shaped sheet sections 124, maintained in assembly by their joint connection to the plastic ` 30 like sheet 128. This arrangement is for a specific purpose which will be discussed; however, it should be kept in mind that the present invention also envisions use of but a single support arrangement wherein the - respective halves are provided by a single layer or .
35 sheet of foam material. The purpose for use of the arrangement wherein the semi-flexible plastic-like Bard Case 14 - 26 ~

sheet 128 interconnects the respective layers 124 is to attain flexibility. More specifically, it can he appreciated that these back pads are rather e~tensive.
Accordingly, with the disclosed arrangement, the cen-tral portion 150 of the plastic-like sheet 128 provides a hinge which permits the respective halves of the electrode to flex and adjust to the contour of the patient's back. Also, as will be apparent in con-junction with the discussion to follow with regard to 10 Figures 21-23, this flexibility facilitates packaging of the electrode 120.

Looking first to Figure 21, the manner Eor packaging or completing the electrode arrangement for storage is 15 shown. As mentioned above, the semi-flexible plastic-like sheet 128 provides a hinge between the respective foam sections 124 of the suppvrt arrangement. This hinge area, the central segment 150 of the sheet 128, does not include por~ions of the conductive pa~tern 20 144 ~roviding the terminal means. Accordingly, the respective foam layers 124 may be folded over upon themselves, as is indicated in Figure 21, without undue flexing of the pattern 144. In this regard, a sheet of release liner material 168 is disposed inter-25 mediate the respective halves of the electrodeJ saidsheet 168 having a release coating on both sides thereof.
As such, the respective halves or sections 124 of the electrode are releasably secured against said sheet 168 in overlapped relation, as is best illustrated in 30 Figures 22 and 23, with the lead wire arrangement 122 coiled as illustrated. As such, there is provided a compact arrangement for packaging and storage purposes.

In Figures 24-29, a still further modified version of 35 the present invention is illustrated. In Figures 24-27 there is shown two forms of a single terminal electrode Bard Case 14 _ 27 -construction, designated 170 and 170' respectlvely. In Figures 28 and 29, there is shown a multi-terminal elec-trode construction using the general concept as to be discussed with respect to the slngle terminal elec-trodes 170 and 170'.

Looking first to Figures 24 and 25, the électrode 170differs from the electrode 30, previously discussed, primarily in that the foam layer 36 and the gelled 10 matrix 54 have been replaced by a specially constructed conductive adhesive layer 171. More specifically, the electrode 170 of Figure 24 is illustrated in exploded fashion with the assembled arrangement being shown in Figure 25, affixed to a patient. The electrode 170 15 is comprised of a sheet of semi-flexible plastic-like material 172 upon which is printed a conductive pattern 174.
The pattern 174 preferably is formed with a silver ink, or some other type of donductive ink printed directly on the shQet material as discussed previously, and said 20 pattern 144 includes a terminal portion 176, and a conductor portion 178. The semi-flexible plastic-like sheet 172 also includes the tab segment 180 adapted to be received within a connector 182 affixed to the end of a lead wire 184 in a manner similar to 25 that as discussed with respect to the electrode of Figures 1-5. It should be noted that the conductor portion 178 extends along the length of the tab 180, which in turn extends from the periphery of the main segment of the electrode, whi.ch conductor portion 178.
30 will be associated in electrical contact with a metal.
terminal housed within the connector 182.

The layer of conductive adhesive is affixed to the major or main segment 173 of the seml-flexible plastic-like sheet 35 172, but does not extend along the tab 180, whereby said tab remains free for engagement within a connector 182. A cover member 190, having a release liner coated surface 191 is provided, which is releasably attached to the under surface of the adhesive layer 171, and can be peeled off or removed for mounting of ~he electrode to the skin 90 of a patient, as is shown in Figure 25.

Due to the conductive properties of the adhesive layer 171, the gel pad or matrix and foam support layer used with the electrodes discussed previously, are not required. As such, the conductive adhesive layer 171 is not apertured, as was the adhesive annulus 43 discussed previously, and overlies the terminal portion 176.

The adhesive layer 171 may be provided by any one of several known electrically conductive adhesives. One such conduc-tive adhesive is produced by Johnson & Johnson Company under the trade mark "BIO-HESIVE", and is disclosed in United States Patent No. 4,066,078. Other conductive adhesives and methods for rendering adhesive materials conductive are known in the art; as for example in United States Patent Nos. 4,008,721; 3,998,215; 3,993,049; and 3,911,90~.
The aforesaid patents disclosed that certain adhesive compositions may be rendered conductive by a number of methods, including the dispersing of conductive 2~ materials such as col~ductive salts or metals throu~h~
out the composition. The adhesive layer 171 o~ the present invention is preferably constructed of a hydrophilic adhesive composition manufactured by Tyndale-Plain-Hunter, L~d., which material may be rendered conductive by any one of the above-noted methods, or other methods known in the art. This hydrophilic material is disclosed Eully in United States Patent Nos. 3,822,23~3; 4,156,066; and ~,156,067.
Basically, the adhesive layer 171 is of a double-sided nature so that it has one surface secured to the semi-flexible plastic-like sheet 172 and an opposed surface for ....

Bard Case 14 ~ ~ ~ 2 attachm~nt to the skin of a patient.

It can be appreciated that the elimination of the foam layer and the gel pad not only reduces the material costs, but also simplifies the method of production of the elec-trode.

A second or modified version of the electrode 170 is illus-trated in Figures 26 and 27, sail modified design being designated 170'. In this regard, the electrode 170' in-cludes a semi-flexible plastic-like sheet 172' with terminal means formed thereon preferably in the orm of a printed ink conduc~ive pattern 174' having a terminal portion 176' and a conductor portion 178l. In place of the tab segment 180 which extends from the periphery of the main portion 173 of the semi-flexible plastic-like sheet 172 of the elec~rode 170, shown in Figure 24, the embodiment of Figures 26 and 27 utilizes a tab 180' in the form of a cut-out depending from the main segment 173' of said sheet. The tab segment extends upwardly from said main segment 173' of the sheet 172' for attachment to a connector 182', as shown.

The electrode 170' also utilizes the conductive adhesive layer 171', as discussed previously. In order to prevent adherence of the t:ab 180' to the double-sided adhesive layer 171', the tab 180 is coated with a medical grade of silicone or the like, during manufacture. Accordingly, upon application of the conductive adhesive layer 171', said tab 180' remains free of adhesion thereto, and can be lifted up out of the plane of the main segment 173' of a flexible sheet 172' for attachment to the conductor. There-fore, except for the manner of forming the tab 180', the electrode 170' is essentially identical to that as discussed with regard to Figures 24 and 25.
Turning now to Figures 28 and 29, there is illustrated a multi-terminal electrode constructed in accordance with the Bard Case 14 concept of the invention as illustrated in Figures 24-27, sald electrode being designated generally 192. The elec-trode 190 is of the type having a lead wire assembly 193 pre-attached thereto. Further, the electrode 190 includes a single sheet of semi-flexible plas~ic-like sheet material 194 having separate individual conductive patterns, 195 printed thereon. Each pattern 195 includes a terminal por-tion 196, and a conductor portion 198. The conductor por-tionsl98cneach half of the semi-flexible plastic-like sheet extend in opposite directions toward each other, and ter-minate proximate a central segment of the sheet. At this location, a crimp-type ~erminal 197 connector carried on the end of each lead wire of the assembly 193 is engaged through the upper surface of ~he semi-flexible plastic-like lS sheet 194 and disposed in electrical contact-with the con-ductor portion 198, of the conductive pattern l9S on the under surfaces of said semi-flexible plastic-like sheet 194.
This connection being best shown in Figure 29, which is a sectional view showing the electrode 192 engaged to the skin 90 of a patient.

As was the case with the electrode 170 and 170l; the elec-trode 192 includes a layer of conductive adhesive 199;
Figure 29 on the ~mder surface of sheet 194. In practice, it is undesirable to have a junction of dissimilar metals such as the copper which may be used for the terminal con-nection 197 and the silver or silver chloride coating on the conductor portion 198 in association with the conductive adhesive 199, as there exists the danger of electrolytic corrosion. Therefore, the joint or connection of the termi-nal 197 with the conductor portion 198 is hermatically sealed by placement of a quantity of epoxy or wax, or some other substance, designated generally 200, over the poin-t of connection on the under side of the sheet 194. The conduc-tive adhesive layer 199 is then applied in overlying rela-tion to the undersurface of the electrode, preferably over the entire electrode. If desired, said adhesive may be Bard Case 14 ~ 3 subject to æoned application, in whatever pattern desired, provided the termlnal portions 196 o the conductive pattern 195 is covered.

While the drawings disclose and the preceding specification discusses various preferred embodiments of ~he inven-tion, it is not the intent to limit said invention thereto, In this regard, it is contemplated that those skilled in the art and possessed of the present disclosure may develop various alternative forms o the invention, without depart-ing from the spiri.t and scope of said invention, as defined in the appended claims.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A disposable medical electrical construction of the type adapted to be adhered to the skin of a patient for operative connection to electrical apparatus, said electrode construction comprising: a support arrangement for an electrical terminal, said support arrangement having aperture means formed therein, and an adhesive coating on a surface thereof for applying the electrode construction to the skin of a patient; a semi-flexible plastic-like sheet secured to said support arrangement and overlying, at least partially, said aperture means in spaced relation to said adhesively coated surface on the support arrangement;
terminal means on said plastic-like, semi-flexible sheet adapted for use in establishing an electrical connection to the electrical apparatus, said terminal means being provided by a thin pattern of conductive ink printed on the surface of said sheet in the area thereof overlying said aperture, said pattern including a terminal portion aligned with said aperture means, said semi-flexible plastic-like sheet further including a tab member extending from the segment thereof having the terminal portion of the ink pattern thereon, the distal end of the tab member being free from attachment to said support arrangement, and said thin conductive ink pattern extending from the terminal portion along the tab member to define a conductive portion, such that said tab member may be inserted into a suitable electrical connector and the conductive portion of said ink pattern brought into contact with terminal means carried by said connector.

2. A disposable medical electrode construction according to claim 1, including means disposed in said aperture means in the form of a porous matrix adapted to retain a quantity of electrolytic gel in association with said terminal portion, and said electrode further including a removable cover means affixed to said adhesively coated surface and overlying said aperture means, said matrix and said adhesive coating.

3. A disposable medical electrode according to claim 2, further including a quantity of conductive electrolytic gel impregnating said porous matrix.

4. A disposable medical electrode according to claim 1, wherein said support arrangement is provided by a sheet of non-porous, flexible foam material with said aperture means being a through aperture and said adhesive coating covering at least a portion of one surface of said sheet, and said flexible plastic-like sheet having the terminal means thereon secured to the opposite surface of said flexible foam material.

5. A disposable medical electrode according to claim 1, wherein said support arrangement includes a sheet of thin flexible, microporous material having said adhesive coating on one surface thereof, and a substantially thicker layer of material affixed to the other side of said flexible microporous sheet, with said aperture means extending through both said microporous sheet and said thicker layer, said semi-flexible plastic-like sheet being affixed to said thicker layer, whereby said aperture means and said semi-flexible sheet define a well, a porous matrix and a quantity of electrolytic gel disposed in said well, and removable cover means affixed to said adhesively coated surface of said microporous sheet and overlying and sealing said well.

6. A disposable medical electrode as defined in claim 1, wherein said tab member includes notch means for retentive engagement with cooperating means on a suitable electrical connector.

7. A disposable medical electrode according to claim 1 wherein said tab member includes aperture means for engagement over post means carried by the electrical connector to be affixed to said tab member.

8. A disposable medical electrode according to claim 1, wherein said plastic-like, semi-flexible sheet is affixed to said support arrangement by means of an adhesive layer, said adhesive layer extending inwardly beyond the periphery of said aperture means and surrounds the terminal portion provided by the conductive ink pattern, a porous matrix disposed in said aperture means and engaged with said semi-flexible sheet with the terminal portion printed thereon, with said porous matrix adhering to said adhesive layer to maintain said matrix in position with respect to said aperture means and said terminal portion.

9. A disposable medical electrode according to claim 1, wherein said support means includes a first sheet of flexible foam material having said aperture means formed therein and said adhesive coating on one surface thereof, said flexible plastic-like sheet being engaged with said first layer of foam material to overlie said aperture means, and a second sheet of adhesively coated thin flexible foam material overlying said semi-flexible plastic-like sheet and a portion of the other surface of said first sheet of foam material to secure said semi-flexible sheet in position.