U.S. patent number 3,827,428 [Application Number 05/311,764] was granted by the patent office on 1974-08-06 for bipolar electrode structure for monitoring fetal heartbeat and the like.
Invention is credited to Edward H. Hon, Robert W. Hon.
United States Patent |
3,827,428 |
Hon , et al. |
August 6, 1974 |
BIPOLAR ELECTRODE STRUCTURE FOR MONITORING FETAL HEARTBEAT AND THE
LIKE
Abstract
An improved electrode system for monitoring fetal heartbeat
includes a curved guide tube adapted to be inserted through the
vagina and cervix of a woman in labor, a retaining coil mounted on
a holder member which is slidably disposed in the guide tube, a
flexible driving tube adapted to rotate the holder member to screw
the retaining coil into a fetal epidermis and two spaced electrodes
which are adapted to be electrically connected to a suitable
apparatus for monitoring fetal heartbeat. In the first disclosed
embodiment of the invention one of the electrodes is a pointed
member mounted in the holder which mounts the retaining coil. The
retaining coil, when screwed into the fetal epidermis, maintains
the pointed first electrode in piercing engagement with the fetus.
In the second disclosed embodiment the retaining coil and the first
electrode are one and the same structure; i.e., the first electrode
is in the form of a coil which is adapted to screw into the fetal
epidermis. In both of the embodiments disclosed the second
electrode is spaced from the first electrode and electrical contact
between the two electrodes is established by vaginal and cervical
secretions of the woman in labor. Driving connection between the
holder member and the flexible driving tube is provided by slots in
the forward end of the driving tube and fin means on the holder. In
the second embodiment disclosed the second electrode is in the form
of a flat member mounted on the rear end of the holder and serves
as the fin means.
Inventors: |
Hon; Edward H. (Bradbury,
CA), Hon; Robert W. (Bradbury, CA) |
Family
ID: |
26805457 |
Appl.
No.: |
05/311,764 |
Filed: |
December 4, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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108034 |
Jan 20, 1971 |
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Current U.S.
Class: |
600/376 |
Current CPC
Class: |
A61N
1/05 (20130101); A61B 5/4362 (20130101); A61B
5/344 (20210101); A61B 5/288 (20210101); A61B
5/25 (20210101) |
Current International
Class: |
A61B
5/0408 (20060101); A61B 5/0444 (20060101); A61B
5/0402 (20060101); A61B 5/0448 (20060101); A61N
1/05 (20060101); A61b 005/04 () |
Field of
Search: |
;128/2.6E,2.6R,2.1E,DIG.4,404,418 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kamm; William E.
Parent Case Text
This application is a continuation-in-part of U.S. Pat. application
Ser. No. 108,034, filed Jan. 20, 1971.
Claims
We claim:
1. An apparatus for use in monitoring fetal heartbeat and the like
comprising:
a relatively rigid, curved guide tube adapted to be inserted
through the vagina and cervix of a woman in labor;
a holder member slidably and rotatably disposed in said guide
tube;
a retaining coil mounted on said holder member and adapted to be
screwed into a fetal epidermis by rotating the holder member;
monitoring means mounted on said holder member;
a flexible drive tube slidably and rotatably disposed in said
curved guide tube for moving said holder member through said guide
tube to bring said retaining coil into engagement with a fetal
epidermis and for rotating said holder member to screw said
retaining coil into the epidermis; and
cooperating means on said drive tube and said holder member for
rotating said holder member and said retaining coil by rotating
said drive tube.
2. The apparatus according to claim 1, wherein said retaining coil
comprises a first electrode.
3. The apparatus according to claim 2, and further comprising a
second electrode mounted on said holder member and spaced from said
first electrode; said holder member comprising insulating
material.
4. The apparatus according to claim 1, and further comprising a
first electrode mounted on said holder member and adapted to
contact the epidermis into which the said retaining coil is
screwed.
5. The apparatus according to claim 1, wherein said drive tube has
a sustantially uniform outer diameter throughout the length
thereof, and said guide tube has a substantially uniform inside
diameter throughout the length thereof; the outer diameter of said
drive tube being smaller than the inside diameter of said guide
tube, whereby said drive tube may be freely slid forwardly and
rearwardly in said guide tube.
6. An improved electrode structure for monitoring fetal heartbeat
and the like comprising:
an elongated, relatively flexible, relatively narrow guide tube
having an open forward end adapted to be inserted through the
vagina and cervix of a woman in labor;
a generally cylindrical holder member slidably and rotatably
disposed within said guide tube; said holder member having a
forward end portion and a rear end portion;
a plurality of circumferentially-spaced driving fins on the rear
end portion of said holder member;
a retaining coil mounted on the forward end portion of said holder
member; said retaining coil terminating in a pointed forward end
spaced forwardly of the forward end of said holder member;
a first electrode mounted in said holder member; said first
electrode including a rear portion mounted in said holder member,
and a pointed forward end extending through the forward end of said
holder member; said pointed forward end of said first electrode
terminating rearwardly of the pointed forward end of said retaining
coil;
a first electrical wire conductor having a forward end extending
through the rear end of said holder member and electrically
connected to said first electrode;
insulating means covering the juncture of said first electrode and
said first electrical wire conductor;
an elongated, relatively flexible driving tube slidably and
rotatably disposed in said guide tube; said driving tube having a
forward end provided with a plurality of axially-extending,
circumferentially-spaced driving slots releasably engaging said
driving fins on said holder member for rotating said holder member
when said driving tube is rotated;
a second electrode slidably disposed within said driving tube,
rearwardly of said slotted forward end thereof;
a second electrical wire conductor having a forward end
electrically connected to said second electrode;
insulation means covering the juncture of said second electrical
wire conductor and said second electrode;
said first and second electrical wire conductors having rear ends
extending out of the rear ends of said driving tube and said guide
tube for connection to an electrical monitoring apparatus.
7. An improved electrode structure according to claim 6, wherein
said driving tube is longer than said guide tube, and has a rear
end portion extending rearwardly of the reare end of said guide
tube; and further comprising an indicator mark on said rear end
portion of said driving tube for indicating to the user when the
pointed forward end of said retaining coil approaches the forward
end of said guide tube.
8. An improved electrode structure according to claim 6, wherein
said second electrode is formed in the shape of a coil, encircling
said first electrical wire to hold said first and second electrical
wires adjacent one another.
9. An improved electrode structure according to claim 6, wherein
said first electrode is made of a silver-silver chloride
composition.
10. An improved electrode structure according to claim 6, wherein
said second electrode is formed in the shape of a tubular
sleeve.
11. An improved electrode structure for use in monitoring fetal
heartbeat and the like comprising:
a relatively rigid, curved elongated guide tube having an open
forward end adapted to be inserted through the vagina and cervix of
a woman in labor;
holder means slidably and rotatably disposed in said guide
tube;
a retaining coil connected to said holder means and adapted to
engage a fetal epidermis;
a flexible driving tube slidably and rotatably disposed in said
guide tube for driving said retaining means into engagement with a
fetal epidermis; said drive tube having a forward end; and means on
said forward end of said driving tube operatively connected to said
retaining coil for rotating said retaining coil to screw said coil
into the fetal epidermis;
an electrode mounted on said holder means; and
means for electrically connecting said electrode to an electrical
monitoring apparatus.
12. An improved electrode structure according to claim 11, wherein
said electrode comprises a pointed electrode spaced from said
retaining coil, and wherein said retaining coil is adapted to
maintain said pointed electrode in engagement with the fetal
epidermis when said retaining coil is screwed into the fetal
epidermis.
13. An improved electrode structure according to claim 11, wherein
said electrode includes at least a portion of said retaining
coil.
14. An improved electrode structure according to claim 11, wherein
said electrode comprises a silver-silver chloride electrode.
15. An improved electrode structure according to claim 11, wherein
said retaining coil is mounted on one end of said holder member;
fin means on the other end of said holder member; and wherein said
means on said forward end of said driving tube comprises a
plurality of slots releasably engaging said fin means on said
holder member for rotating said holder member and said retaining
coil when said driving tube is rotated.
16. An improved electrode structure according to claim 11, and
further comprising a second electrode disposed in said guide tube
rearwardly of said first electrode, and means for electrically
connecting said second electrode to an electrical monitoring
apparatus.
17. An improved structure for use in monitoring fetal heartbeat and
the like comprising;
a relatively rigid, elongated, curved guide tube having an open
forward end adapted to be inserted through the vagina and cervix of
a woman in labor;
a holder member sliably and rotatably disposed within said guide
tube; said holder member having a forward end portion and a rear
end portion;
a retaining coil mounted on the forward end portion of said holder
member; said retaining coil terminating in a pointed forward end
spaced forwardly of the forward end of said holder member;
electrode means mounted on said holder member;
an elongated, relatively flexible driving tube slidably and
rotatably disposed in said guide tube; and
cooperating engaging means on said rear end portion of said holder
member and the forward end portion of said driving tube for
rotating said holder member and said retaining coil by rotating
said driving tube.
18. An apparatus for monitoring fetal heartbeat and the like
comprising:
a relatively rigid guide tube having an open forward end; said
guide tube being curved to conform to and fit the angular
anatomical configuration of a woman's vagina and cervix so as to be
adapted to be comfortably inserted through the vagina and cervix of
a woman in labor;
a holder member adapted to be slidably and rotatably disposed in
said guide tube; said holder member having a forward end and a rear
end;
an electrode coil mounted on said forward end of said holder member
and being adapted to be screwed into an epidermis when said holder
member is rotated; said electrode coil having a pointed forward end
adapted to pierce an epidermis;
a flexible driving tube adapted to be slidably and rotatably
disposed in said curved guide tube for selectively moving and
rotating said holder member and said electrode coil; said driving
tube having a forward end;
cooperating drive means on said driving tube and on said holder
member for rotating said holder member and said electrode coil when
said driving tube is rotated; and
means for electrically connecting said electrode coil to an
electrical monitoring apparatus.
19. The apparatus according to claim 18 and further comprising a
second electrode mounted on said rear end of said holder member and
spaced from said first electrode; said holder member comprising
insulating material electrically insulating said first and second
electrodes from one another.
20. The apparatus according to claim 19, wherein said second
electrode comprises a generally flat member, and wherein said
cooperating drive means comprises slots in the forward end of said
driving tube and a portion of said flat second electrode.
21. An improved structure for use in monitoring fetal heartbeat and
the like comprising:
a relatively rigid, elongated guide tube having an open forward;
said guide tube being curved to conform to and fit the angular
anatomical configuration of a woman's vagina and cervix so as to be
adapted to be confortably inserted through the vagina and cervix of
a woman in labor;
a holder member slidably and rotatably disposed within said guide
tube; said holder member having a forward end portion and a rear
end portion;
a retaining coil mounted on the forward end portion of said holder
member; said retaining coil terminating in a pointed forward end
spaced forwardly of the forward end of said holder member;
monitoring means mounted on said holder member;
an elongated, relatively flexible driving tube slidably and
rotatably disposed in said guide tube; and
cooperating engaging means on said rear end portion of said holder
member and the forward end portion of said driving tube for
rotating said holder member and said retaining coil by rotating
said driving tube; said cooperating engaging means on said rear end
portion of said holder member and on the forward end portion of
said driving tube establishing a relatively loose connection so
that the engaging means on the forward end of said driving tube
will slip around said engaging means on the rear end portion of
said holder member when the holder member meets with a
predetermined amount of resistance to rotation.
22. An improved structure according to claim 21, wherein said
cooperating engaging means on said rear end of said holder member
and the forward end of said driving tube comprise fin means on one
of said holder member or said driving tube and slots in the other
of said holder member or said driving tube.
23. An improved structure for use in monitoring fetal heartbeat and
the like comprising:
a relatively rigid, elongated guide tube having an open forward;
said guide tube being curved to conform to and fit the angular
anatomical configuration of a woman's vagina and cervix so as to be
adapted to be comfortably inserted through the vagina and the
cervix of a woman in labor;
a holder member slidably and rotatably disposed within said guide
tube; said holder member having a forward end portion and a rear
end portion;
a retaining coil mounted on the forward end portion of said holder
member; said retaining coil terminating in a pointed forward end
spaced forwardly of the forward end of said holder member;
monitoring means mounted on said holder member;
an elongated, relatively flexible driving tube slidably and
rotatably disposed in said guide tube; and
fin means on said rear end of said holder member and means defining
slots in the forward end of said driving tube for releasably
engaging said fin means and rotating said holder member and said
retaining coil by rotating said driving tube; the portions of the
forward end of said driving tube between said slots being
relatively soft and flexible to establish a relatively loose
connection with said fin means so that the forward end of said
driving tube will slip around said fin means on the rear end
portion of said holder member when the holder member meets with a
predetermined amount of resistance to rotation.
24. An apparatus for use in monitoring fetal heartbeat and the like
comprising:
a holder member;
a retaining coil mounted on said holder member and adapted to be
screwed into a fetal epidermis by rotating the holder member;
monitoring means mounted on said holder member;
an elongated tube for moving said holder member to bring said
retaining coil into engagement with a fetal epidermis and for
rotating said holder member to screw said retaining coil into the
epidermis; and
slots in the forward end of said tube and fin means on said holder
member, whereby said holder member and said retaining coil may be
rotated by rotating said tube.
25. An improved electrode structure for use in monitoring fetal
heartbeat and the like comprising:
holder means having fin means thereon;
a retaining coil connected to said holder means and adapted to
engage a fetal epidermis;
a driving tube for driving said retaining means into engagement
with a fetal epidermis; said drive tube having a forward end; and
slots in said forward end of said driving tube operatively
connected to said fin means on said holder means for rotating said
holder means and said retaining coil to screw said coil into a
fetal epidermis;
an electrode mounted on said holder means; and
means for electrically connecting said electrode to an electrical
monitoring apparatus.
26. An improved structure for use in monitoring fetal heartbeat and
the like comprising:
a relatively rigid, elongated outer tube having an open forward end
adapted to be inserted through the vagina and cervix of a woman in
labor;
a holder member slidably and rotatably disposed within said outer
tube; said holder member having a forward end portion and a rear
end portion;
a retaining coil mounted on the forward end portion of said holder
member; said retaining coil terminating in a pointed forward end
spaced forwardly of the forward end of said holder member;
monitoring means mounted on said holder member;
an elongated driving tube disposed in said outer tube; and
fin means on said holder member and slots in the forward end
portion of said driving tube for rotating said holder member and
said retaining coil by rotating said driving tube.
Description
The present invention relates to an improved bipolar electrode
structure adapted to be inserted through the vagina and cervix of a
woman in labor, into contact with the fetus. The electrode
structure is designed to be operatively connected to an amplifier
and a cardiotachometer for recording the fetal electrocardiogram
and heart rate during labor and delivery.
It has long been recognized that monitoring fetal heartbeat is a
most important procedure during the conduct of labor. Various types
of methods and apparatuses for performing this monitoring function
have been designed in recent years. The most successful and
practical techniques are those employing electrodes which are
attached to the fetus.
One such technique is described in Volume 35, No. 1, of Obstetrics
and Gynecology, January 1970 issue, pages 111-113. The technique
there described utilizes a vaginal endoscope and specially designed
forceps to apply a silver electrode to the fetal scalp.
A second type of electrode structure for recording fetal heartbeat
is described in Volume 16, No. 5 of Obstetrics and Gynecology,
November 1960 edition, pages 567-570. The electrode structure there
described is a unipolar structure comprising a spring steel clip
adapted to be closed by a sliding plastic sleeve to engage the
fetal scalp or buttocks.
The foregoing electrode structures give rise to several problems
which the structure of the present invention is designed to
overcome. Both the "forceps-endoscope" and the "sliding
sleeve-clip" types of electrodes cannot be applied until the
mother's cervix has dilated to about 2.0 cm, and thus cannot
ordinarily be applied during the very early stages of labor.
Another disadvantage associated with the foregoing types of
electrodes is that both include clips which must be squeezed onto
the fetal epidermis. These clips are extremely thin and brittle and
are often cracked or damaged by mechanical stresses during
application. Such cracks create electrical "noise" in the
electrocardiogram system during the fetal heartbeat monitoring
operation, and thus interfere with such monitoring studies.
The foregoing types of electrodes are also relatively difficult to
apply and remove. The "forceps-endoscope" system requires a
specially designed lighting apparatus which must be used to insure
proper application of the electrode.
In view of the foregoing, it is an object of the present invention
to provide a vaginal electrode structure which overcomes the
foregoing problems associated with the prior art electrode
structures.
A further object of the present invention is to provide an
improved, durable, vaginal electrode structure which can be quickly
and effectively applied to the fetus during a relatively early
stage of labor, and which can be quickly and easily removed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional side elevational view of the forward portion
of a first preferred embodiment of the electrode structure of the
present invention, with the various parts thereof positioned as
they would be prior to use.
FIG. 2 is a perspective view of the holder member, first electrode,
retaining coil and the forward end of the driving tube of the
electrode structure shown in FIG. 1.
FIG. 3 is a sectional side elevational view of the rear portion of
the electrode structure shown in FIGS. 1 and 2.
FIG. 4 is a sectional side elevational view showing the electrode
structure of FIGS. 1-3 with a modified form of the second
electrode.
FIGS. 5, 6 and 7 are diagrammatic views illustrating the manner in
which the improved electrode structure of the present invention is
applied to a fetus.
FIG. 8 is a perspective view of a second preferred embodiment of an
electrode structure constructed according to the teachings of the
present invention, wherein the retaining coil serves as the first
electrode and wherein the first and second ellectrodes are mounted
on the same holder.
FIG. 9 is a sectional side elevational view of the electrode
structure shown in FIG. 8 with the various parts thereof positioned
as they would be prior to use.
FIG. 10 is a side elevational view, partly in section, showing the
electrode unit rotated 90 degrees from the position illustrated in
FIG. 9.
DESCRIPTION OF EMBODIMENT OF FIGS. 1-7
Referring now to the drawings, the electrode structure 10
illustrated in FIGS. 1, 2 and 3 comprises a guide tube 12 having an
open forward end through which a holding member 14 is movable, and
an open rear end through which electrode wires 16, 18 extend. The
guide tube 12 is curved (see FIGS. 5-7) to facilitate insertion of
the tube through the vagina and cervix of a woman in labor.
One of the wires 16 extends through the holding member 14 and is
electrically connected to a pointed electrode 20 which is
preferably made of silver-silver chloride. The desirability of
using a silver-silver chloride electrode is discussed in some
detail in Volume 30, No. 2 of Obstetrics & Gynecology, August
1967 issue, pages 281-286. The electrode 20 is preferably crimped
on the forward end of wire 16, as at 22 (FIG. 1) and soldered
thereto to insure a good electrical connection.
An insulating sleeve 24 covers the juncture of the first wire 16
and the first electrode 20. Epoxy adhesive 26 fills and seals the
annular space between the insulation 17 of wire 16 and the interior
wall of the holder 14, behind the sleeve 24. The epoxy 26 also
covers and seals the rear end of the holder 14.
Epoxy adhesive is also provided in the annular space 28 between the
electrode 20 and the interior wall of tube 24, in the annular space
30 between the wire 16 and the interior wall of the tube 24, in the
annular space between the wire insulation 17 and the interior wall
of tube 24, and in the annular space 36 between the exterior wall
of tube 24 and the interior wall of the holder 14. The epoxy
adhesive at these locations insures a good seal from the forward
end of the holder 14.
The forward end 40 of the holder 14 has a retaining coil 42 mounted
thereon by means of a suitable adhesive 44 (e.g., epoxy). The
retaining coil 42 (which may be plastic, metal or any other
suitable material) is provided with a pointed forward end 46 to
pierce the fetal epidermis. When the holding member 14 and the
retaining coil 42 are rotated the retaining coil will "screw" into
the fetus and bring the first electrode 20 into engagement with the
fetal epidermis with the pointed tip 47 piercing the epidermis. The
forward end 40 of the holder 14 acts as a "stopper" which limits
the distance which the tip 47 of the first electrode 20 can travel
into the fetus. The distance between the pointed end 46 of the
retaining coil 42 and the forward end 40 of the holder member 14 is
relatively small (e.g., about 1/16 of an inch).
As best shown in FIG. 2, the rear portion 49 of the holder member
14 is provided with a plurality of radially outwardly extending,
circumferentially spaced wings or fins 50, 50, 50, 50, which are
adapted to be releasably engaged by circumferentially spaced slots
52, 52, 52, 52, in the forward end 53 of a flexible driving tube
54.
The flexible driving tube 54 (preferably made of plastic) extends
through the curved guide tube 12 for rotating the holder 14 and the
retaining coil 42. As noted above, rotation of the holder 14 by the
flexible driving tube 54 is accomplished via the slots 52 in the
forward end 53 of the driving tube and the fins 50 on the holder.
It should be noted that the driving connection between the fins 50
and the slots 52 is relatively "loose" so that thhe driving tube 54
will "slip" around the holder fins 50 when the holder meets with a
relatively slight amount of resistance to rotation. Thus, when the
holder 14 meets with resistance to rotation (e.g., when the first
electrode 20 has pierced the fetal epidermis and the forward end of
the holder has come into contact with the fetus), continued
rotation of the driving tube 54 will not drive the retaining coil
or first electrode further into the fetus. This "loose driving
connection" may be accomplished by making the fins 54 or the
driving tube segments 56 between the slots 52 "soft" or pliable
enough so that they will bend and "slip" relative to one another
when the holder 14 resists rotation.
Referring to FIG. 1, it will be seen that the forward end of the
second conductor 18 terminates within the guide tube 12
substantially behind the holder 14. A silver-silver chloride
electrode coil 60 is crimped (as at 62, FIG. 1) and soldered onto
the forward end of the second conductor 18. The coil 20 is the
second electrode in the system and also functions to hold the
conductors 16, 18 adjacent to one another.
A plastic insulating sleeve 64 is provided around the juncture of
the electrode coil 60 and the second conductor 18 to eliminate or
minimize any electrical noise which otherwise might be created if
the juncture of the conductor 18 and the electrode coil 60 were
exposed to vaginal fluids when the system is in use.
Epoxy adhesive is preferably provided between the interior wall of
the insulating sleeve 64 and the rear end of the coil electrode 60
to seal the forward end of the insulating sleeve. Epoxy adhesive is
also preferably provided between the conductor 18 and the interior
wall of the insulating sleeve 64 (as at 66, FIG. 1), and between
the interior wall of the insulating sleeve 64 and the insulation
cover 19 on the second conductor 18 to seal these junctures.
In FIG. 4, an alternative structure for the second electrode is
shown. In the FIG. 4 embodiment the second electrode 160 is in the
form of a sleeve which is crimped and soldered onto the forward end
of the second conductor 18 and an insulating sleeve 164 encloses
both of the conductors 16, 18. Epoxy adhesive is preferably
provided in the FIG. 4 structure to seal the juncture between the
electrode sleeve 160 and the conductor 18 from vaginal fluids.
As best shown in FIG. 1, the electrode structure 10 of the present
invention is packaged so that the retaining coil 42 and the first
electrode 20 are well behind the forward end of the guide tube 12,
thereby protecting the retaining coil and electrode from damage
prior to use.
As best shown in FIG. 5, the rear ends of the wires 16, 18 are
folded back and inserted between the rear end of the curved guide
tube 12 and the rear portion of the flexible driving tube 54. A
wedge 80 (FIGS. 5 and 7) may be inserted in the rear end of the
driving tube 54 to prevent relative sliding movement between the
flexible driving tube and the wires 16, 18.
The method of using the electrode structure 10 of the present
invention is illustrated diagrammatically in FIGS. 5, 6 and 7.
With the first and second electrodes, 20 and 60, disposed within
the guide tube 12, the doctor inserts the forward end of the curved
guide tube through the mother's vagina 82 and cervix 84 until the
forward end of the guide tube makes contact with the fetal head 86
(or other portion of the fetus), as shown in FIG. 5. The doctor
then removes the folded-back ends of the wires 16, 18 from between
the rear ends of the guide tube 12 and the driving tube 54 to
permit relative sliding movement between these tubes. While holding
the forward end of the guide tube 12 stationary, the doctor then
pushes the rear end of the flexible driving tube 54 forwardly until
the retaining coil 42 makes contact with the fetal epidermis (FIG.
6). An indicator mark 88 (FIGS. 5-7) may be provided on the driving
tube 54 to visually warn the doctor when the retaining coil 42 has
passed beyond the forward end of the guide tube 12.
When the doctor feels or sees that the retaining coil 42 has
contacted the fetal epidermis 86, he rotates the flexible driving
tube 54 (e.g., about one full turn) while maintaining the forward
end of the guide tube 12 against the fetal head. This will screw
the retaining coil 42 into the fetal epidermis and drive the
pointed end of the first electrode 20 into the epidermis (see FIG.
6). It will be appreciated that the flexible construction of the
driving tube 54 permits it to slide and rotate in the curved guide
tube 12.
The wedge 80 is then removed from the rear end of the driving tube
54 to permit relative sliding movement between the wires 16, 18 and
the driving tube. The doctor then removes his fingers from the
mother's vagina 82, grasps the outer ends of the driving tube and
the guide tube, and slides these tubes (as a unit) off of the wires
16, 18 leaving only the electrodes 20 and 60, and the very thin
wires 16, 18 within the mother.
The outer ends of the wires 16, 18 are then connected to suitable
apparatus (not shown) for monitoring fetal heartbeat.
DESCRIPTION OF THE EMBODIMENT OF FIGS. 8-10
FIGS. 8-10 illustrate a second preferred embodiment of the
electrode structure of the present invention wherein the first
electrode serves as the retaining coil and the second electrode is
mounted on the holder member and serves as the fin means which
cooperates with the slots in the forward end of the flexible
driving tube to provide the driving connection between the holder
and the driving tube.
Referring to FIG. 9, the electrode structure 210 comprises a curved
guide tube 212 having an open forward end through which a holder
member 214 is adapted to pass. The holder member 214 has a spiral
electrode 220 mounted in its forward end and a generally flat
electrode 222 mounted in its rear end.
A first electrode wire 216 extends through the rear end of the
holder member 214 and is electrically connected to the rear end of
spiral electrode 220. A second electrode wire 218 also extends
through the rear end of holder member 214 and is electrically
connected to the forward end of the second electrode 222.
Both electrodes, 220 and 222, are preferably constructed of
stainless steel and are soldered to their respective electrode
wires, 216 and 218. The holder member 214 is made of an insulative
material, such as plastic, and electrically isolates the electrodes
220 and 222 from one another.
A flexible driving tube 254 is slidably and rotatably disposed in
the curved guide tube 212 for rotating the holder 214 to screw the
spiral electrode 220 into a fetal epidermis. As best shown in FIG.
8, the forward end of the driving tube 254 is provided with a pair
of slots 252, 252 which are adapted to receive the rearwardly
extending portion of the plate electrode 222. When the slots 252,
252 on the forward end of the holder 214 engage the plate electrode
222 the holder 214 and the spiral electrode 220 may be rotated by
rotating the flexible driving tube 254.
The electrode wires, 216 and 218, extend rearwardly through the
rear portion (not shown) of the driving tube 254 and the rear
portion (not shown) of the guide tube 212 for connection to a
suitable apparatus (not shown) for monitoring fetal heartbeat.
The electrode structure 210 is used in the same manner as described
above and illustrated in FIGS. 5-7 in connection with the structure
of FIGS. 1-7. In use, with the spiral electrode 220, holder 214 and
plate electrode 222 disposed within the curved guide tube 212,
behind the forward end thereof, the doctor inserts the forward end
of the guide tube 212 through the woman's vagina and cervix until
the forward end of the guide tube makes contact with the fetal head
(or other portion of the fetus) in the same manner as described
above in connection with the electrode structure 10 illustrated in
FIGS. 1-7. The doctor then holds the forward end of the guide tube
212 stationary and pushes the rear end of the flexible driving tube
254 forwardly until the spiral electrode 220 makes contact with the
fetal epidermis.
When the doctor feels or sees that the spiral electrode 220 has
contacted the fetal epidermis, he rotates the flexible driving tube
254 while maintaining the guide tube 212 against the fetal head to
screw the spiral electrode 220 into the fetal epidermis.
It is intended that the present invention be limited only by the
scope of the appended claims.
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