U.S. patent number 3,720,209 [Application Number 05/092,767] was granted by the patent office on 1973-03-13 for plate electrode.
Invention is credited to Lee R. Bolduc.
United States Patent |
3,720,209 |
Bolduc |
March 13, 1973 |
PLATE ELECTRODE
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.
Inventors: |
Bolduc; Lee R. (Minneapolis,
MN) |
Family
ID: |
27377265 |
Appl.
No.: |
05/092,767 |
Filed: |
November 25, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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711949 |
Mar 11, 1968 |
3543760 |
|
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866630 |
Oct 15, 1069 |
3642008 |
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Current U.S.
Class: |
600/395; 607/152;
128/908 |
Current CPC
Class: |
A61N
1/04 (20130101); A61B 18/16 (20130101); G01R
31/52 (20200101); G01R 31/58 (20200101); G01R
31/54 (20200101); A61B 5/276 (20210101); A61B
5/274 (20210101); Y10S 128/908 (20130101) |
Current International
Class: |
A61B
18/16 (20060101); A61B 18/14 (20060101); A61B
5/0408 (20060101); A61B 5/0416 (20060101); A61B
5/0424 (20060101); A61M 25/00 (20060101); A61N
1/04 (20060101); G01R 31/02 (20060101); A61b
005/04 () |
Field of
Search: |
;128/303.13-303.19,404,410,413,416-418,2.6E,422 ;24/243,243.15
;339/228,229,230,261,259,259F,255,255P |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Trapp; Lawrence W.
Parent Case Text
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.
Claims
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 one-piece 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 flange is 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 50 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 non-conductive 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 contacts 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 non-conductive 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 non-conductive 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 of a 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 comprising: a one-piece sheet member
having an electrically non-conductive base, an electrically
conductive skin means secured to one side of the base and
engageable with the electrical conductor means, 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, one edge of said sheet member having a
portion turned 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.
Description
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 have been 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 patient's heart. It is a common practice to engage
separate electrodes at different points relative to the front of
the patient's 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 electro-surgical 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 7--7 of
FIG. 6;
FIG. 8 is an enlarged sectional view taken along line 8--8 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 12--12
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. 15 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
.times. 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 100 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 rectangular-shaped 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 113 and 114 are
curved or arcuate to eliminate sharp points and edges which may cut
the patient or personnel in the operating theater.
As shown 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 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 electrode 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 3/8 to 1/2 inch. The rounded corners have a radius
of 1 inch and the flap has a width of 1/2 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 the levers 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 123B 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 122B.
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 122B can each 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 122B and corresponding
surfaces on the legs 123A and 123B, 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
123B from the legs 123A and 123B. 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 122B 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. S. 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 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
electrically couple the electrode 200 with the recording mechanism
201.
Electrode 200 has a flexible base 207 made of non-conductive sheet
material as cardboard, paper, plastic and the like. Preferably the
base 207 is a cardboard sheet impregnated with plastic material
which increases the thermal characteristics of the base and makes
the base liquid-proof and autoclavable. The base 207 may be
flexible sheet plastic foam, as polyurethane 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 portions 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. 11, 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 2-1/2 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
231 against the arm 229 and thereby biases the arms 228 and 229
together into engagement with opposite sides of the electrode 213.
When lever 231 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 example, 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 of a 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.
The disposable ground plate electrode shown in FIG. 5 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 180 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
microampere cannot 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 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 patient's 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 patient's 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 311. 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 current 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 electro-surgical 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.
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