US 3720209 A
A one-piece disposable electrode having a flat flexible base of non-electrical conductive sheet material. An electrical conductive skin is secured to one side of the base. The skin is divided into separate sections engageable with distinct portions of a body. Clamps and cables are used to attach the electrode to an electrical-surgical machine, an electrocardiograph recording mechanism, or a device coupled to a cardiac catheter.
Description (OCR text may contain errors)
United States Patent 1191 Bolduc PLATE ELECTRODE Lee R. Bolduc, Minneapolis, Minn.
Assignee: Medical Plastics Inc., Minneapolis,
Filed: Nov. 25, 1970 Appl. No.: 92,767
Related 0.5. Application Data Continuation-in-part of Ser. Nos. 711,949, March 1 1, 1968, Pat. No. 3,543,760, and Ser. No. 866,630, Oct. 7 15, 1069, Pat. No. 3,642,008.
US. Cl. ..128/2.06 E, 128/416 Int. Cl. ..A6lb 5/04 Field of Search ..128/303.13303.l9, 128/404, 410, 413, 416-418, 2.06 E, 422; 24/243, 243.15; 339/228, 229, 230,261,
[5 6] References Cited UNITED STATES PATENTS Frankel ..339/97 Frankel ....339/3l Buck ..24/252 Eads ..339/176 1March 13, 1973 Primary Examiner-Lawrence W. Trapp AttorneyBurd, Braddock & Bartz  ABSTRACT A one-piece disposable electrode having a flat flexible base of non-electrical conductive sheet material. An electrical conductive skin is secured to one side of the base. The skin is divided into separate sections engageable with distinct portions of :a body. Clamps and cables are used to attach the electrode to an electrical-surgical machine, an electrocardiograph recording mechanism, or a device coupled to a cardiac catheter.
37 Claims, 16 Drawing; Figures 20/ 204 I j 202 ll l CONVENTIONAL 1] 208/1 E K e RECORDING MECHANISM ll 206 l llll I b l l") I Ill PATENTEDHARHIGTS 720,209
SHEET 30F 4 20 207 Z00 v I II I I I I E .I p CONVENTIONAL 208 E K e I REcoRDI e 209A I .---207, MECHANISM I |l F J0 MW? ME I I 2/2 209 3K 21 k I I I 1 HI Y I wJE ILE CONVENTIONAL 1 E Ks I RECORDING MECHANISM I 226 Q7 I Ill I III I j 244 241 242 23$ Z1 u. gig I CONVENTIONAL a l II v EKG Z46 RECORDING 1 "fl7" MECHANISM \252 25% 25 3 Iii 9 239 i j 74 INVENTOR. FILE-L25 LEE R. BOLDUC BY .fimcfi/laaldoczfiwf AT TORNEYS I PLATE ELECTRODE CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of U. S. Patent application Ser. No. 711,949, filed Mar. 11, 1968, now U. S. Pat. No. 3,543,760 and U. S. Pat. application Ser. No. 866,630, filed Oct. 15, 1969, now U. S. Pat. No. 3,642,008.
BACKGROUND OF THE INVENTION In 1907, Pozzi demonstrated fulguration as a cure for malignant disease to the Paris Academy of Medicine, using an Oudin resonator and unipolar current of a frequency around half a million cycles per second. His results were by no means uniform, and it was left to Iredell and Turner, in 1919, to demonstrate true diathermy by providing a plate, 6 by 12 inches, for the return circuit. They showed that the effects of the treatment were entirely due to heat destruction of tissues and were first to use a water pipe to ground both the indifferent electrode and the patient. This contribution to safety has remained until the present day. In use, heat is developed at both the active electrode and the indifferent or ground electrode, commonly a lead plate, in surface contact with the skin of a patient. The heat generated is inversely proportional to the square area of these electrodes. The ground electrode must be of a certain size and has to make uniform contact all over its surface so that the heat is diffused over a wide area. If the ground electrode has point contacts, the patient can be severely burned. In some instances, two ground electrodes are used at the same time to insure adequate grounding of the patient.
Efficient functioning and safety of electrical-surgical machines depends upon an unimpaired return of current via the indifferent ground electrode and its cable. If this fails, then the current will choose the next best route, which will mean a short circuit to ground with a consequent risk of a diathermy burn. Some machines are equipped with a ground test stud that requires the operating staff, before each operation, to check the circuit. This system only monitors the continuity of the cable and its attachment to the ground electrode. It does not monitor the electrical contact and conductivity between the ground electrode and the patient.
Various materials are used for the ground plate electrodes. The material should be a good conductor and easily malleable. Lead plates havebeen the most practical to use. Electrodes have been made of stainless steel, aluminum, brass, silver, zinc and tin, as suggested by Wappler, U. S. Pat. No. 1,662,446; Huth, U. S. Pat. No. 1,853,814; Ruben, U. S. Pat. No. 1,973,911; and Howell, U. S. Pat. No. 2,943,628.
Electrodes including plate electrodes are used in conjunction with conventional recording mechanisms used to monitor the electrical signal from a patients heart. It is a common practice to engage separate electrodes at different points relative to the front of the patients body to make a separate contact with the body. An electrode assembly is designed for this use and is disclosed in U. S. Pat. Nos. 2,943,628 and 3,476,104.
The use of catheters in the human provides potential for electrocution because the instruments can be conductors of electricity. Many of the electrocution accidents are caused by faulty equipment and people who fail to recognize the hazards. The remedy to this problem is to ground all elements of the system. Many factors make total grounding of all elements of the system at all times almost impossible. The plate electrode of the invention can be used with catheters and other electrical apparatus to reduce these electrocution hazards.
SUMMARY OF THE INVENTION The invention relates to an electrode usable to ground a patient or monitor electrical signals generated by the patient. The electrodes are used in conjunction with electrosurgical units, as a component of an electrocardiograph apparatus, and with a cardiac catheter. The electrode has a flexible electrically insulated base carrying an electrically conductive skin means. The entire skin means is secured to one side of the base.
One form of the electrode has a flexible base sheet member carrying electrically conductive skin means separated into two skin sections. A clamp having a pair of spaced electrical contact members with flat surfaces is attached in surface engagement with the separate skin sections of the ground plate electrode. Another form of the electrode has a plurality of spaced electrically conductive skin means carried by a flexible sheet base member. The separate electrical conductive skin means are connected with suitable connectors as wires, clamps and jacks to an electrocardiograph recording mechanism.
IN THE DRAWINGS FIG. 1 is a diagrammatic view of the electro-surgical unit equipped with a ground plate electrode of the invention;
FIG. 2 is a perspective top view of the electrode positioned on an operating table;
FIG. 3 is an enlarged sectional view taken along the line 3-3 of FIG. 2;
FIG. 4 is a sectional view similar to FIG. 3 showing the flange folded over adjacent the base of the electrode;
FIG. 5 is an enlarged plan view of the ground plate electrode showing the area indicia lines and the fold line for the end flange;
FIG. 6 is a diagrammatic view of an electro-surgical unit having a split skin ground plate electrode attached to a bipolar clamp connected to circuit testing unit;
FIG. 7 is an enlarged sectional view taken along the line 77 of FIG. 6; 1
FIG. 8 is an enlarged sectional view taken along lin Z 88 of FIG. 6;
FIG. 9 is a plan view of a split ground plate electrode having a clamp locater hole with parts broken away;
FIG. 10 is a diagrammatic view of an electrode connected to an electrocardiograph recording mechanism;
FIG. 11 is a modified electrode connected to an electrocardiograph recording mechanism;
FIG. 12 is an enlarged sectional. view taken along the line l212 of FIG. 10;
FIG. 13 is a further modification of a plate electrode connected to an electrocardiograph recording mechanism;
FIG. 14 is a sectional view of an electrode having a plastic foam base;
FIG. is a diagrammatic view of a device having a cardiac catheter attached to a plate electrode located under the body of a patient positioned on a table; and
FIG. 16 is a diagrammatic view, partly sectioned, of the cardiac catheter and plate electrode of FIG. 15.
Referring to the drawings, there is shown in FIG. 1, an electro-surgical unit indicated generally at 10 illustrated in an operating environment theater on a patient 11 lying on a table 12. An upright base 13 supports the table 12 above floor 14 to locate patient 11 in a convenient position for surgeon 16.
The electro-surgical unit 10 uses high frequency current from a portable transformer 17 connected to a power supply and an active electrode 18 by a cable or line 19. A ground plate electrode or indifferent electrode, indicated generally at 21, connected by a cable or line 22 to transformer 17 completes the circuit through the patient. A releasable connector or clamp, indicated generally at 23, electrically couples cable 22 with the ground plate electrode 21. The opposite end of cable 22 is connected to a test and control unit, indicated generally at 24, plugged into the transformer 17. A test and control unit is disclosed in U. S. Patent application Ser. No. 866,630, now U. S. Pat. No. 3,642,008. Under operating conditions, high frequency currents flow through the patient 11 from the active electrode 18 and return to the ground through electrode 21 located under the patient 11 on the table 12. The placement of the ground plate electrode 21 on the patient varies according 'to the surgical area. The electrode 21 may be placed under the buttock, or wrapped around an arm or leg, to provide a maximum area of flesh or skin contact. For proper patient grounding it has been found that a substantial electrical surface contact is required between patient 11 and electrode 21. An example of electrode 21 is shown in FIG. 5. This electrode has 154 square inches of electrically conductive skin. The requirement is that there be substantial electrical surface contact with a body for proper grounding. If the area is too small, chances for burning are substantially increased. A 100 square inch contact area provides for a margin of safety. The ground plate electrode 21 is operative with skin areas of less than 100 square inches, as well as with skin areas that are greater than 100 square inches. Plate electrodes usable with children, may have only 50 square inches of electrically conductive skin. The effectiveness of the ground plate electrode is also dependent upon the conductivity of the skin of'the patient, as well as the type of metal used in the ground plate electrode.
Ground plate electrode 21 is a generally rectangular flexible sheet member capable of being shaped to fit the contour of the parts of the body, as a leg or arm. As shown in FIG. 2, the electrode 21 is placed on the top of table 12 so as to engage a large area of the skin in the posterior of the patient 11.
As shown in FIG. 3, ground electrode 21 has a flat and flexible base layer 26 which may be made of cardboard, paper or similar flexible and electrically insulative material. Located over the top surface of the base layer 26 is an electrical conductive skin 27. Skin 27 can be a metal sheet or foil, as aluminum foil. The base layer 26 is impregnated with a plastic material which bonds the skin 27 to the base layer 26. The plastic material increases the thermal characteristics of the electrode so that it can be placed in the autoclave for sterilization and is liquid proof.
A specific example of electrode 21 usable as a disposable item with an electro-surgical unit is as follows: The base layer is an 11 X 14 inch rectangular sheet of flexible, electrically insulative, cardboard about 0.024 0.022 inch thick. A 0.003 inch aluminum foil covers the entire top surface of the cardboard and is bonded to the top surface of the cardboard with plastic bonding material impregnated in the cardboard. The plastic material makes the cardboard liquid and waterproof and autoclavable.
An end flange or flap 28 of electrode 21 is turned over and secured to the back of the base 26 with a bonding material 29, as adhesive or glue, to form a stop edge 31. The releasable connector 23 cooperates with stop edge 31 to prevent the accidental removal of the connector. The plastic impregnated in the base 26 may be utilized to bond the base and flange 28 together thereby to eliminate the bonding material 29.
As shown in FIG. 4, flange 28 can be folded under the base to provide the stop edge 31 without securing the flange to the base.
As shown in FIG. 5, ground electrode 21 has a generally rectangular shape with the flange 28 extended transversely across the electrode 21. The skin 27 of the electrode has broken guide lines 32 to outline a square area approximately square inches. The lines are parallel to the sides and ends of the electrode. Lines 32 outline a 10 inch square. In a similar manner broken lines 33 outline a rectangular area which is generally 100 square inches. Lines 33 also extend parallel to the sides and ends of the electrode and outline an area of approximately 100 square inches. Extended across the end of electrode 27 is a broken fold line 34 providing a guide for turning flange 31 under base layer 26 as shown in FIG. 8. Flange 28 may be prefolded and secured to base layer 26 as shown in FIG. 3.
Referring to FIG. 6, there is shown a diagrammatic view of an electrical-surgical unit, indicated generally at 106, connected to a split ground plate electrode 107 with a cable 108 and a releasable bipolar connector or clamp, indicated generally at 109. The cable 108 connects the clamp to a circuit testing unit 111 plugged into the electrical-surgical unit 106. The electric circuit through the patient is completed by the use of an active electrode coupled to a cable extended back to the electrical-surgical unit 106, as illustrated in FIG. 1.
The ground plate electrode 107 is a rectangularshaped one-piece sheet member having a transverse flap or scored end 112 cooperating with the clamp 109 to prevent the accidental disengagement of the clamp from the ground plate electrode. The corners 1l3 and 114 are curved or arcuate to eliminate sharp points and edges which may cut the patient or personnel in the operating theater.
Asshown in FIG. 7, the ground plate electrode 107 has a flat and flexible base 114 which may be made of cardboard, paper, or similar flexible and electrically insulative material. Secured to the top of the base 114 is a pair of spaced electrically conductive skins 116 and 117 having flat and smooth surfaces. The skins 116 and 117 are located in a 'side-by-side relation and are separated from each other by a longitudinal space 118 extended down the longitudinal center line of the 174 permits the easy and convenient folding of the flap prior to insertion into the clamp. The corners 176 and 177 of the opposite end of the electrode are rounded or curved to eliminate any sharp points or edges. Inwardly of the flap 173 in the midsection of the base 168 is a clamp locater hole 178. The electrode 167 can be provided with two other holes 178A and 178B for the purpose of locating and holding a clamp on the electrode.
Referring to FIG. 10, there is shown a bipolar electrode, indicated generally at 200, used in conjunction with a conventional electrocardiograph (EKG or ECG) recording mechanism 201 or an ECG viewer. Lines or cables 202 and 203 connected to clamps 204 and 206 foam, polystyrene foam and polyester foam. Located along the opposite sides of the top of base 207 are elongated longitudinal conductive skins 208 and 209. The skins 208 and 209 along one edge of the base have por' tions 208A and 209A that extend toward each other so that they can be engaged with a single bipolar clamp, as shown in FIGS. 6 and 8. Each skin can be a relatively thin layer of metal, as metal foil or sprayed metal including but not limited to aluminum, tin, copper, silver, and anodized aluminum. The electrically conductive skins 208 and 209 can be sprayed or deposited on the base 207. The skins can be silver dust, carbon particles or like electrical conductive particles, comprising a filler for polyethylene, polyurethane or polypropylene plastic material. The filler is preferably approximately 80 per cent of the plastic material.
FIG. 14 shows an electrode 210 having a plastic foam base 211 carrying an electrical conductive skin or coating 212. Base 211 can be polyurethane foam bonded to an aluminum foil skin 212.
Referring to FIG. 1 1, there is shown a further modification of the electrode, indicated generally at 213, connected to a conventional electrocardiograph recording mechanism 214 with cables 227 or lines 216, 217 and 218 and clamps 219, 221 and 222. Electrode 213 has a relatively flat flexible base 223 of electrically non-conductive sheet material. The base may be made of the same material as the base 204 described above. Secured to the corner portions of the base 223 are a plurality of separated electrically conductive skins 224, 225, 226 and 227. The skins 224-227 are substantially equal in area and shape and may be of electrical conductive metal or coating that is the same as skins 208 and 209 described above. For example, each skin has a dimension of 2-% inches by 4 inches. The base has a size of 8 inches by 14 inches. The skin 227 can be alternatively connected to the recording mechanism 214 in lieu of one of the other skins 224, 225 and 226, depending on the position of the electrode relative to the patient.
Referring to FIG. 12, there is shown a clamp 222 in assembled relation with the electrode 213. The clamp 222 has a U-shaped body having relatively flat upper and lower arms 228 and 229 separated from each other with a transverse slot 231. The outer ends 228A and 229A of the arms 228 and 229 are directed inwardly toward each other to grip the opposite sides of the electrode 213. Line 218 is attached to the base of the arms. Arms 228 and 229 are biased toward each other with a pivotally mounted lever 231 attached to a transverse lip 232. The lip 232 can have a plurality of teeth to grip the base. Opposite ends of the lip 232 have have short projections rotatably mounted in holes in upright ears 233 secured to opposite sides of the top lever 228. The outer end 234 of the lever 231 has a step or projection to provide a grip to permit the lever to be moved as indicated by the arrow 236. As shown in FIG. 11, the lip 232 is in the over-center position forcing the lever 23] against the arm 229 and thereby biases the arms 228 and 229 together into engagement with opposite sides of the electrode 213. When lever 23] is moved away from arm 229, lip 232 will also move away from arm 229 thereby opening the clamp. The clamps shown in FIGS. 10,11 and 13 can be the same as clamp 222.
Referring to FIG. 13 there is shown a further modification of the electrode, indicated generally at 237, connected to conventional electrocardiograph recording mechanism 238 with cables or lines 239, 240, 241 and clamps 242, 243 and 244. The electrode 237 has a generally flat base 246 of non-conductive sheet material similar to the base 207. Secured to one side of the base are a pair of first skins 247 and 248 located on opposite corners of the base 246. A second skin 249 is attached along the entire opposite side of the base. A lead or electrically conductive strip 251 extends from the skin 248 to one edge of the base and ends in an end tab 252.
A cover or mast 253 of non-electrically conductive material is secured to the base to cover the strip 251. The base and skins of electrodes 223 and 237 can be the same materials as that described for the electrode 200. The electrodes can vary in size and shape. For ex ample, the electrodes could be round, square, triangular, as well as rectangular in shape. The skins can also vary in size and shape. The base can be the size ofa bed sheet. The skins can be located in; the mid-portion of a bed sheet-sized base. The process of applying or attaching the skins to the base may include an adhesive bond, a bonding reaction between the base and skins, as well as plastic impregnated material in the base to attach the skins to the base.
In use, the electrode is placed under the body of a patient located in a prone position. The electrical conductive skins are in electrical engagement with the back of the patient. With the electrode coupled to the electrocardiograph recording mechanism, an electrocardiogram can be prepared in a conventional manner.
The body of the patient is a shield against outside electrical interference and the weight of the body serves to provide effective electrical contact with the skins of the electrode.
The electrode of the invention is a one-piece disposable member having one or more electrically conductive skin means for providing an electrical contact between a patient and the electrode. The electrode is usable as a ground plate electrode in electro-surgical procedures as well as EKG electrodes to monitor electrocardiographic impulses.
ground plate electrode 107. The skins 116 and 117 may be sheet metal or metal foil, as aluminum foil, bonded to the base 114. The skins have smooth continuous top surfaces and outer peripheral edges 119 that are turned down into the adjacent edges of the base 114. The turned down edges 119 provide rounded edges around the entire ground plate, thereby eliminating any sharp edges which may injure the patient or operating personnel. The base 114 is impregnated with a plastic material which bonds the skins 116 and 117 to the top of the base. Other chemicals and materials can be used to treat and liquid-proof the base. The plastic material increases the thermal characteristics of the ground plate electrode 107 so that it can be placed in an autoclave for sterilization. In addition, the plastic material makes the entire ground plate electrode liquid-proof. The plastic material functions to maintain a continuous bond between the skins and the base so that the elec trode may be flexed and wrapped around a patient without separating the skin from the base or cracking the base. The back side of the base can be printed with instruction and inventory code information with ink that does not run or react with liquids or change with heat.
A specific example of the bipolar ground plate electrode 107, usable as a disposable electrode with an electrical-surgical unit, is as follows: The base 114 is a cardboard sheet member having rectangular dimensions of 8 by 13 inches. The base is electrically insulative cardboard about 0.024 0.022 inch thick. The skins 116 and 117 are 0.003 inch aluminum foil bonded with plastic material to the top of the base. The base 114 is entirely impregnated with plastic material. The longitudinal center space 118 extends the entire length of the electrode, including the flap 112. The space has a width of to 75 inch. The rounded corners have a radius of 1 inch and the flap has a width of 1: inch. Other sizes and shapes of the ground plate electrode and the skins 116 and 117 are intended to be within the scope of the invention.
As shown in FIG. 8, the bipolar clamp 109 has a pair of movable levers 122 and 123. Forward portions of thelevers engage opposite sides of the electrode 107. Lever 122 has a first flat contact nose or plate 122A and a second contact nose or plate 122B separated from the first contact plate with an electrically insulative strip 124. The strip 124 separates the lever 122 into separate electrical conductors. The lower lever 123 is also separated into two electrical conductors, each having rearwardly directed plates 123A and 1238 separated from each other with an electrically insulative strip 125. The plates 123A and 123B have flat upper surfaces that face the flat contact surfaces of the plates 122A and 1228.
Projected downwardly from the forward portion of the insulation strip 124 is a projection or pin 126 which extends through a hole 127 in the ground plate electrode 107 and a hole 128 in the insulation strip 125 of lever 123. The hole 127 is located in the space 118 of the ground plate electrode 107 adjacent the flap 112. Plates 122A and 1228 caneach be provided with a projection or pin adapted to extend through suitable spaced holes in the ground plate electrode. The use of two pins prevents rotation of the clamp relative to the ground plate electrode. The entire clamp 109, except for the contact plates 122A and 1228 and corresponding surfaces on the legs 123A and 1238, is coated with an electrically insulative material, as an electrically insulative plastic. This coating prevents the grounding of the patient through the clamp and thereby avoids any contact burns.
The clamp 109 is releasably attached to the ground plate electrode 107 by compressing the outer ends of the levers 122 and 123 to open the mouth of the clamp by separating the contact plates 122A and 1238 from the legs 123A and 1238. The ground plate electrode 107 with the flap 112 in the folded position, as shown in FIG. 10, is inserted into the clamp. The middle of the clamp 109 is aligned with the space 118 by aligning the projection 126 with the hole 127 and the ground plate electrode 107. This positions the contact plate 122A in flat surface engagement with the skin 116 and the contact plate 1228 in surface engagement with the skin 117. The projection 126, by extending through the hole 128 in the lower lever 123, prevents the accidental removal upon disengagement of the clamp 109 from the electrode 107. The only way the clamp 109 can be removed from the electrode 107 is to depress and open the clamp to remove the projection 126 from the electrode 107. The purpose of aligning the bipolar clamp 109 so that one electrical contact portion 122A engages one skin 116 and the other contact plate 122B engages skin 117, is to provide a structure and electrical circuit capable of monitoring the efficiency of the electrical conductivity between the ground plate electrode 107 and the skin of a patient, as well as the electrical connection between the clamp 109 and the ground plate electrode 107 and the continuity of the cable 108. The circuit testing unit 111 functions to form these tests. This unit is disclosed in detail in U. 8. Patent application Ser. No. 866,630, now U. S. Pat. No. 3,642,008.
Referring to FIG. 9, there is shown a ground plate electrode 167 having a generally rectangular shape. Electrode 167 has a flexible base 168 which can be made of cardboard, paper, wood, and similar material. The base is substantially flat, flexible, and electrically insulative. Attached to the top of the base 168 is a pair of substantially identical electrical conductive skins 169 and 171. The skins are spaced from each other .along the longitudinal center line of the base with a uniform longitudinal space 172. The skins 169 and 171 are electrically conductive sheet members having flat continuous and smooth top surfaces. The skins 169 and 171 may be made of sheet metal, metal foil, and like electrically conductive material, as aluminum foil. The skins can be bonded or secured to the top of the base 168 with an adhesive or plastic material embedded in the base 168. Other chemicals, bonding and adhesive materials can be used to treat and liquid-proof the base, as well as bond the skins 169 and 171 to the base 168. The treatment of the base increases its thermal characteristics, as well as its resistance to chemical action and liquids, as water, blood, and the like. The peripheral edges of the ground plate are rounded to eliminate any sharp edges which may injure a patient or operating personnel, as shown in FIG. 7.
One end of the ground plate electrode has a flap or flange 173 extended across the end of the electrode and defined with a crease or fold line 174. The crease The disposable ground plate electrode shown in FIG. is usable with a patient during surgery, catherization and routine electro-cardiography to ground and provide an alternate electrical circuit to the patient. The ground plate is used to minimize the induction of ventricular fibrillation or multiple extra systoles when an electrical apparatus is connected to the patient. It is known that alternating current having 60 cycle per second frequency as used in the United States is among the most prone to cause ventricular fibrillation. The threshold of ventricular fibrillation with 60 cycle alternating current shocks administered to human hearts is very low, in the neighborhood of I80 microamperes. With a safety factor of 10 it has been found that shocks exceeding 2 microamperes of 60 cycle alternating current is regarded as hazardous if delivered directly to the human heart. Human studies indicate that 60 cycle shocks are 500 to 5000 times more dangerous when delivered directly to the heart rather than to the body surface. The very small magnitude of the shocks capable of producing ventricular fibrillation may be appreciated in the light of the observation at 60 cycles that currents less than 1 microamperecannot be detected through the skin. Saline of blood filled cardiac catheters and pacemaker electrodes are the usual means of gaining electrical access to the human heart.
To minimize the electrocution hazards, the voltage 0 difference between the table and the patient and the apparatus or device which may be attached directly to the heart or any other part of the body must be eliminated or reduced to less than a few microamperes of current. In the present invention, the apparatus is connected to a disposable ground plate in surface contact with the skin of the patient to shunt or bypass any electrical current that may flow between the apparatus and the patients heart.
Referring to FIG. 15, there is shown a patient 300 located on a table 301. An electrical apparatus, indicated generally at 302, having an electrically conductive saline solution 303 is connected directly to a patients heart 304 and a source of alternating current 305 used to operate the apparatus. The apparatus 302 comprises an intra-cardiac catheter 306. The catheter 306 is an elongated flexible plastic tube for carrying the saline solution 303 to one of the chambers of the heart 304. A coupling 307 is used to connect the catheter to a dye injector 31 1. The coupling 307 has an electrically conductive body 308 of metal or the like carrying a non-electrically conductive coating or skin 309. The dye injector 311 may be replaced with a densimeter or other apparatus for monitoring the condition of the heart.
As shown in FIG. 15, a plate electrode, indicated generally at 312, is located on the table 301 in surface engagement with the back of the patient 300. The electrode 312, shown in FIG. 16, has a substantially flat base 313 of electrically non-conductive material, as cardboard. Secured to one side of the base 313 is an electrically conductive skin 314 of aluminum, tin, or similar conductive metal. The skin and base may be of the same materials as used in electrodes 21 and 200, described above. An electrical conductor 316, as a line or wire, is connected to a clamp 317. Clamp 317 is in engagement with skin 314. The line 316 is secured to the body 308 of the connector 307 and thereby electrically connects the fluid or saline liquid 303 with the electrode 312.
In use, the electrode 312 shunts or shorts away most of the current from the heart 304. The line 316 and electrode 312 together have less resistance to the cur-' rent than the saline liquid in the catheter 306. The ratio of the resistance between the line 316 and electrode 312 together compared to saline column in the catheter 306 is between 300 to 500 to 1. This ratio depends upon the diameter and/or length of the saline column. Accordingly, the amount of current applied to the heart is reduced by this factor. The plate electrode 312 along with the connecting line 316 in electrical contact with the saline liquid 303 will substantially reduce the incidence of ventricular fibrillation of the heart 304.
While there has been shown and described a disposable plate electrode for use with an electrosurgical unit, an electrocardiograph apparatus, and an intra-cardiac catheter, it is intended that the electrode can be used with other electrical apparatus for either grounding or monitoring electrical signals from a patient.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. An electrode for engaging the surface of a body and releasably attachable to an electrical connector having electrical conductor means comprising: a onepiece flexible electrically non-conductive sheet member having a generally flat base .layer of flexible material, said base layer having a surface on at least one side thereof, electrically conductive flexible skin means substantially covering at least one surface of the base layer, said skin means having a substantial electrically conductive external surface area for engagement with the surface of a body to make a large surface electrical contact between the skin means and the body,
and means securing the entire inner side of said skin means to said one surface of the base layer, one edge of said sheet member having a flange terminating in an edge.
2. The electrode of claim 1 wherein: said flangeis secured to the base layer.
3. The electrode of claim 1 wherein: said skin means is an aluminum sheet.
4. The electrode of claim 1 including: indicia means on the sheet member outlining a minimum external surface area of the skin means to ensure an electrical contact of the electrode.
5. The electrode of claim 1 wherein: the minimum external surface area is at least square inches.
6. The electrode of claim 1 including: indicia means comprising lines on the sheet member outlining at least one minimum external surface area.
7. A plate electrode comprising: a one-piece generally flat sheet member having a flexible electrically nonconductive base, said base having a surface, a first skin of electrically conductive material located on a first portion of said surface of the base, a second skin of electrically conductive material spaced from the first skin located on a second portion of said surface of the base, said first skin and second skin having electrically conductive external surface areas for engagement with the surface of a body to make surface electrical con tacts between both skins and the body, and means securing the inner sides of the first skin and second skin to said one surface of the base.
8. The electrode of claim 7 wherein: the first skin and second skin have substantially the same external surface areas.
9. The electrode of claim 8 wherein: the first skin and second skin are longitudinally separated along the central portion of the base.
10. The electrode of claim 7 wherein: said electrode has at least one round corner.
11. The electrode of claim 7 wherein: the first skin and second skin each have edge portions that are turned adjacent the edges of the base.
12. The electrode of claim 7 wherein: said sheet member has a transverse scored end adapted to be folded back.
13. The electrode of claim 7 wherein: the means securing the skins to the surface comprise material impregnated into the base to bond the first skin and second skin to the base.
14. A plate electrode comprising: a one-piece generally flat sheet member having a flexible electrically non-conductive base, said base being a flat flexible cardboard, a first skin of electrically conductive material secured to a first portion of one side of the base and a second skin of electrically conductive material spaced from the first skin secured to a second portion of said one side of the base, said first skin and second skin comprising separate sheets of aluminum longitudinally separated along the midsection of the base, and liquid-proof material impregnated throughout the cardboard base to bond the aluminum to the base.
15. The electrode of claim 14 wherein: said sheet member has a pair of round corners and said first and second skins each have edge portions that are turned adjacent the edges of the cardboard base.
16. The electrode of claim 7-wherein: said sheet member has at least one hole adjacent one edge thereof.
17. An electrode comprising: a flexible sheet member having a flat flexible base of electrically nonconductive cardboard, an electrically conductive aluminum skin means secured to and substantially covering at least one surface of the base, said skin means having a substantial surface area for engagement with the surface of a body to make a large surface electrical contact between the skin means and the body, and plastic material impregnated in the cardboard bonding the entire inner side of the skin means to said base.
18. The electrode of claim 17 wherein: said skin means comprise a plurality of separated skins attached to the base.
19. A plate electrode comprising: a one-piece generally flat sheet member having an electrically nonconductive base, said base having a surface, a plurality of separated skin means of electrically conductive material located on separate portions of said surface of the base, said skin means having electrically conductive external surface areas for engagement with the surface of a body to make surface electrical contacts between said skin means and the body, and means securing the entire inside surfaces of the skin means to the surface of the base.
20. The electrode of claim 19 wherein: said plurality of skin means comprise a first skin and a second skin longitudinally separated along the center portion of the base.
21. The electrode of claim 19 wherein: the base has corners and the plurality of skin means comprises an electrically conductive skin at each corner of the base.
22. The electrode of claim 19 wherein: said plurality of skin means comprises a first longitudinal skin along one side of the base and a pair of separated skins located along the opposite side of the base.
23. The electrode of claim 22 including: electrical conductor means connected to one of said pair of skins to provide an electrical connection along an edge of the base common with the first skin and the other of said pair of skins.
24. An electrode comprising: a flexible sheet member having a base layer, said base layer being a generally flat flexible cardboard sheet, an electrically conductive skin comprising an aluminum sheet covering one side of the cardboard sheet, said skin having a substantial electrically conductive external surface area for engagement with the surface ofa body to make a large surface electrical contact between the skin and the body, bond liquid-proof material impregnated throughout the cardboard sheet to bone the aluminum sheet to said cardboard sheet.
25. The electrode of claim 1 wherein: said sheet member has at least a pair of rounded corners.
26. The electrode of claim 1 wherein: said sheet member has at least one hole adjacent one edge thereof.
27. The electrode of claim 1 wherein: said sheet member has a transverse scored fold line along one edge of the flange.
28. The electrode of claim 17 wherein: said sheet member has at least a pair of round corners.
29. The electrode of claim 17 wherein: said sheet member has at least one hole adjacent one edge thereof.
30. The electrode of claim 17 wherein: at least one end of the sheet member has a transverse scored end adapted to be folded back toward the base.
31. An electrode releasably attachable to an electrical connector having electrical conductor means and projection means comprising: a one-piece, generally flat and flexible sheet member, said sheet member having an electrically non-conductive base, said base being generally flat and having a surface on one side thereof, and electrically conductive skin means of a size to cover the surface of the base and adapted to be engaged by the conductor means when the connector is attached to the sheet member, said skin means having separate sections and a substantial surface area for engagement with the surface of a body to make large surface electrical contact between the skin means and the body, and means to secure the entire inside face of the skin means to said surface thereby covering said surface, at least one hole in said sheet member adjacent one edge thereof and between the separate sections of the skin means defining a stop edge engageable with said projection means to prevent accidental separation of the connector from the sheet member.
32. The electrode of claim 31 wherein: the hole is located adjacent one end of the sheet member.
33. The electrode of claim 31 wherein: the sheet member has at least one round corner.
34. The electrode of claim 31 wherein: the skin means has edge portions that are turned adjacent the edges of the base.
35. A plate electrode for engaging the surface of a body and releasably attachable to an electrical connector having electrical conductor means and leg means on itself forming a flange with a stop edge, said stop edge adapted to be engageable with said leg means to prevent accidental separation of the connector from the sheet member.
36. The electrode of claim 19 wherein: the plurality of skin means comprise three separate electrically conductive skins.
37. The electrode of claim 36 wherein: at least two of said skins have substantially the same external surface area.