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.

We claim: 
     
       1. An apparatus for use in monitoring fetal heartbeat and the like comprising: a .[.relatively rigid.]. .Iadd.form-sustaining.Iaddend., 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.].   .Iadd.said guide tube being more rigid than said drive tube so that said guide tube will maintain its curved configuration when said flexible drive tube is rotated within it; and .Iaddend.   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 substantially 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, rigid.]. .Iadd.form-sustaining.Iaddend., 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; .Iadd.   said guide tube being more rigid than said driving tube so that said guide tube will maintain its curved configuration when said flexible driving tube is rotated within it; .Iaddend.   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.]. .Iadd.rear .Iaddend.end of said guide 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.]. .Iadd.form-sustaining.Iaddend., 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.]. .Iadd.driving .Iaddend.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; .Iadd.   said guide tube being more rigid than said driving tube so that said guide tube will maintain its curved configuration when said flexible driving tube is rotated within it; .Iaddend.   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.]. .Iadd.form-sustaining.Iaddend., 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 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;   electrode means mounted on said holder member;   an elongated, relatively flexible driving tube slidably and rotatably disposed in said guide tube; .[.and.]. .Iadd.   said guide tube being more rigid than said driving tube so that said guide tube will maintain its curved configuration when said flexible driving tube is rotated within it; and .Iaddend.   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.]. .Iadd.form-sustaining .Iaddend.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; .Iadd.   said guide tube being more rigid than said driving tube so that said guide tube will maintain its curved configuration when said flexible driving tube is rotated within it; .Iaddend.   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.]. .Iadd.form-sustaining.Iaddend., elongated guide tube having an open forward .Iadd.end.Iaddend.; 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.]. .Iadd.   said guide tube being more rigid than said driving tube so that said guide tube will maintain its curved configuration when said flexible driving tube is rotated within it; and .Iaddend.   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.]. .Iadd.form-sustaining.Iaddend., elongated guide tube having an open forward .Iadd.end.Iaddend., 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.]..Iadd.   said guide tube being more rigid than said driving tube so that said guide tube will maintain its curved configuration when said flexible driving tube is rotated within it; and .Iaddend.   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.]. .Iadd.form-sustaining.Iaddend. , 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.]. .Iadd.   said guide tube being more rigid than said driving tube so that said guide tube will maintain its curved configuration when said flexible driving tube is rotated within it; and .Iaddend.   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. .Iadd. 27. A fetal electrode structure for use in monitoring fetal heartbeat, comprising:   an elongated, cylindrical, form-sustaining guide tube curved to conform to and fit the angular anatomical configuration of a woman's vagina and cervix so as to be comfortably inserted through the vagina and cervix of a woman in labor, said guide tube having a forward end and a rear end and being adapted to maintain its curved configuration when a flexible driving tube is rotated within it;   a cylindrical holder slidably and rotatably disposed in said guide tube, said holder being made of an electrically insulating material and having a forward end surface and a rear end surface, the length and diameter of the holder being such as to prevent substantial lateral movement and skewing of said holder relative to said guide tube when the forward portion of said holder extends from said guide tube;   an electrode coil extending from the front end surface of said cylindrical holder and terminating in a forward, pointed end adapted to pierce a fetal epidermal layer;   a second electrode extending rearwardly from the rear end surface of said cylindrical holder, said second electrode being electrically insulated from said electrode coil;   a flexible driving tube slidably and rotatably disposed in said guide tube, said driving tube having a forward end and a rear end, said guide tube being more rigid than said driving tube;   first and second wires passing through said driving tube into the rear end surface of said holder and electrically contacting said electrode coil and second electrode, respectively, said wires extending from the rear end of said driving tube;   cooperating engaging means on the rear end surface of said holder and the forward end of said driving tube for releasably connecting said driving tube and said holder for rotating said holder about its axis within said   
     
     
        guide tube. 28.  A fetal electrode structure according to claim 27, further comprising means for selectively holding said wires at the rear end of said driving tube for locking said cooperating engaging means together. 29. A fetal electrode structure according to claim 27, wherein said cooperating engaging means comprises said second electrode and slots in the forward end of said driving tube for engaging said second electrode. 30. A fetal electrode structure according to claim 29, wherein said second electrode comprises a flat plate. 31. A fetal electrode structure according to claim 27, wherein said second electrode comprises a flat metal plate. 32. A fetal electrode structure according to claim 30, further comprising means for selectively holding said wires at the rear end of said driving tube for locking said cooperating engaging means together. 33. A fetal electrode structure according to claim 27, including means on said driving tube for indicating when said electrode coil extends a preselected distance beyond the forward end of said guide tube. 34. A fetal electrode structure according to claim 27, wherein the outer diameter of said driving tube is less than the diameter of said holder. 
     
     
             A fetal electrode structure for use in monitoring fetal heartbeat, comprising: a form-sustaining, elongated cylindrical guide tube curved to conform to and fit the angular anatomical configuration of a woman's vagina and cervix so as to be comfortably inserted through the vagina and cervix of a woman in labor, having a forward end and a rear end;   a cylindrical holder having a front face and a rear face, the cylindrical surface of said holder engaging the inner surface of said guide tube for enabling slidable movement and rotation of said holder within said guide tube;   an electrode coil extending from the front face of said cylindrical holder and terminating in a forward, pointed end adapted to pierce a fetal epidermal layer;   a flat electrode fin perpendicular to the rear face of said cylindrical holder, said electrode fin substantially located on a diameter of said rear face and being electrically insulated from said electrode coil;   a relatively flexible driving tube slidably and rotatably disposed in said guide tube, said driving tube having a forward end and a rear end;   said guide tube being more rigid than said driving tube so that said guide tube will maintain its curved configuration when said flexible driving tube is rotated within it;   first and second wires passing through said driving tube into the rear face of said holder and electrically contacting said electrode coil and flat electrode fin, respectively, said wires extending rearwardly from the rear end of said driving tube;   slots in the forward end of said driving tube for releasably engaging said electrode fin; and   means for selectively holding said wires at the rear end of said driving   
     
     
        tube for locking said slots and flat electrode fin together. 36.  A fetal electrode structure according to claim 35, wherein said driving tube includes arcuate drive segments between said slots, said arcuate drive segments being sufficiently pliable to slip over said electrode fin when the rotational drive force transmitted from said driving tube to said holder exceeds a predetermined limit..Iaddend.