US3361129A - Annular electrode assembly for a plethysmograph - Google Patents

Annular electrode assembly for a plethysmograph Download PDF

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Publication number
US3361129A
US3361129A US471891A US47189165A US3361129A US 3361129 A US3361129 A US 3361129A US 471891 A US471891 A US 471891A US 47189165 A US47189165 A US 47189165A US 3361129 A US3361129 A US 3361129A
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United States
Prior art keywords
electrode
members
support
plethysmograph
electrode assembly
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Expired - Lifetime
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US471891A
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English (en)
Inventor
Figar Stepan
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Czech Academy of Sciences CAS
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Czech Academy of Sciences CAS
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow
    • A61B5/026—Measuring blood flow
    • A61B5/0295—Measuring blood flow using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
    • A61B5/053—Measuring electrical impedance or conductance of a portion of the body
    • A61B5/0535—Impedance plethysmography

Definitions

  • This invention relates to the investigation of blood circulation and of other factors which affect the volume of portions of the human body, and particularly to plethysmography.
  • the invention is concerned with an adjustable annular electrode assembly for a plethysmograph in which changes in the distance between a sensing electrode and a portion of the body cause variations in the capacitance of a circuit, and which is equipped with indicating or recording means for displaying the capacitance changes as a function of the varying distance.
  • an electrode assembly for a plethysmograph and the like which is more sensitive than the known devices and which yields useful data on localized volume changes.
  • the invention in one of its aspects, resides in an electrode assembly in which a plurality of electrode members is angularly spaced about the axis of a passage through a rigid annular support, Resilient fasteners secure the electrode members to the support in the passage. Pressure devices are interposd between the support and respective electrode members for moving the associated members in a direction toward the axis against the resilient force of the fasteners. The support, the fasteners, and/or the pressure device electrically insulate the electrode members from each other.
  • FIG. 1 shows an annular electrode assembly of the invention in plan view
  • FIG. 2 shows the device of FIG. 1 in elevation, and partly in section on its axis
  • FIG. 3 illustrates a modified annular electrode assembly in fragmentary plan section on its median radial plane
  • FIG. 4 illustrates a sensing device for a plethysmograph mainly consisting of electrode assemblies of the type shown in FIGS. 1 and 2 in elevation.
  • FIGS. 1 and 2 there is shown an annular element of the sensing device illustrated in FIG. 4.
  • An outer support ring is a low, hollow metal cylinder.
  • One of its axially terminal faces has an integral annular ridge 11, and the other terminal face has a recess 12 shaped and dimensioned to receive the ridge 11 of another identical ring 10 in c0- axial engagement.
  • spacers of resilient insulating material such as rubber or another elastomer are secured to 3,361,129 Patented Jan. 2, 1968 the inner face of the ring 10 by an adhesive,
  • the spacers are segments of a ring of I-shaped cross section as best seen in FIG. 2.
  • the width of the two flange portions of each spacer is not quite equal to the axial height of the ring 10, and the web portion extends in the median radial plane of the ring 10.
  • the three spacers 20 are offset from each other in a circumferential direction, and their radially inner flange portions carry circumferentially and axially coextensive electrode plates 36 which are attached to the spacers by adhesive.
  • Each electrode plate 30 is a segment of a hollow cylinder.
  • Threaded radial bores in the ring 10 are aligned with openings in both flanges of the spacers 2t) and receive screws 40 of rigid insulating material such as non-plasticized polyvinyl chloride.
  • the heads of the screws 40 are accessible outside the ring 10.
  • the free ends of the screw shanks are normally in abutting engagement with the electrodes 30.
  • Three screws 40 are associated with each spacer 20 and the attached electrode plate 31).
  • the nine screws are uniformly angularly offset about the axis of the ring 10, and are arranged in two axially spaced planes.
  • the two circumferentially outer screws 40 associated with the same electrode plate 3h are in one of the planes, and the circumferentially central screw is in the other plane.
  • a lead 31 is conductively secured to each electrode plate and passes radially outwardly through the two flanges of the associated spacer, and through the ring 1t) from which each lead 31 is insulated in a conventional manner, not shown.
  • FIGS. 1 and 2 may be combined to form a sensing device as shown in FIG. 4.
  • the illustrated device has six electrode assemblies, each identical with that described in more detail above, but only the six support rings 10 have been shown for the sake of clarity.
  • the screws 4t) and leads 31 have been omitted.
  • the several rings 10 are coaxially juxtaposed, and their ridges 11 and recesses 12, not visible in FIG. 4, are conformingly engaged.
  • the ends of the tubular body so formed are provided with metallic covers 18, 19 coaxially aligned with the ringsltl by ridges 11 and recesses 12.
  • Each cover is basically a fiat circular disk formed with a central circular aperture 28, 29 whose rim is thickened.
  • the diameter of each aperture 28, 29 is somewhat smaller than the diameter of the generally cylindrical passage defined by the electrode plates 30 in the relaxed condition of the spacers 20, and selected to hold an inserted finger or the like in a fixed position relative to the rings 10.
  • Each of the eighteen electrode plates 30 of the sensing device shown in FIG. 4 may be moved radially toward the surface of the inserted finger by turning the associated three screws 40 an equal number of turns.
  • the plate may also be tilted to some extent about two axes at right angles to each other to bring it as close as possible to a surface element of the finger without touching the same.
  • the eighteen leads may be connected to a suitable capacitance bridge equipped with an eighteen-channel recorder to provide individual readings of volume changes in eighteen different areas on the inserted finger.
  • Its support ring 19 is of glass, but other insulating material may be used if so desired.
  • Three plugs of elastomeric material are fastened to the inner cylindrical face of the ring 10 at uniform distances by screws 26.
  • Three electrode plates are each made of a spring metal strip whose central portion is bent into a circular arc, whereas the two ends extend radially outward, and engage respective faces of two plugs 25 under the circumferential spring tension of the electrode plate.
  • the metallic rings 19 of the sensing device shown in FIG. 4 provide electrical shielding for the electrode assemblies and may be grounded.
  • the glass rings 10' cannot perform this function, but external shielding may be provided in an obvious manner.
  • At least one of said support, said fastening means, and said pressure means including means for electrically insulating said electrode members from each other.
  • said fastening means including a plurality of fastening members of elastomeric material radially interposed between said support and respective electrode members, said fastening members being attached to said support and to the respective electrode members.
  • said fastening means including a plurality of fastening members of elastomeric material circumferentially interposed between respective pairs of angularly spaced electrode members,
  • each fastening member being attached to said support in said passage and engaging the members of the associated pair of electrode members.
  • said pressure means including three spaced threaded pressure members abuttingly engaging each of said electrode members, said pressure members engaging said support for threaded movement in a direction extending radially relative to the axis of said support, two of said three pressure members being spaced from the third pressure member in an axial direction, and two of said three pressure members being spaced from each other in a circumferential direction.
  • a sensing device for a plethysmograph and the like comprising, in combination:
  • said supports jointly constitute a tubular body, the sensing device further comprising two covers on the axial end faces of said body, said covers being formed with apertures axially aligned with said passages and of smaller cross section.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Physics & Mathematics (AREA)
  • Veterinary Medicine (AREA)
  • Biophysics (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Hematology (AREA)
  • Public Health (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Radiology & Medical Imaging (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Cardiology (AREA)
  • Physiology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
  • Measuring Fluid Pressure (AREA)
US471891A 1964-07-25 1965-07-14 Annular electrode assembly for a plethysmograph Expired - Lifetime US3361129A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CS430564 1964-07-25

Publications (1)

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US3361129A true US3361129A (en) 1968-01-02

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US471891A Expired - Lifetime US3361129A (en) 1964-07-25 1965-07-14 Annular electrode assembly for a plethysmograph

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US (1) US3361129A (da)
DE (1) DE1466785A1 (da)
DK (1) DK115486B (da)
SE (1) SE315070B (da)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4296754A (en) * 1978-07-04 1981-10-27 Hennig Ewald M C Method for determining the value of cardiologic quantities and apparatus for performing said method
CN105411587A (zh) * 2015-12-07 2016-03-23 天津大学 用于人体胸腔电阻抗层析成像的胸腔轮廓数据采集方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2667159A (en) * 1948-12-21 1954-01-26 Harold D Goldberg Plethysmograph
US2755796A (en) * 1951-03-27 1956-07-24 Radio Patents Company Electrostatic transducers
US3156237A (en) * 1963-03-08 1964-11-10 Physio Control Company Inc Apparatus for measuring blood pressure and heartbeat pulses
US3189024A (en) * 1962-05-31 1965-06-15 Dynamics Corp America Blood pressure transducer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2667159A (en) * 1948-12-21 1954-01-26 Harold D Goldberg Plethysmograph
US2755796A (en) * 1951-03-27 1956-07-24 Radio Patents Company Electrostatic transducers
US3189024A (en) * 1962-05-31 1965-06-15 Dynamics Corp America Blood pressure transducer
US3156237A (en) * 1963-03-08 1964-11-10 Physio Control Company Inc Apparatus for measuring blood pressure and heartbeat pulses

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4296754A (en) * 1978-07-04 1981-10-27 Hennig Ewald M C Method for determining the value of cardiologic quantities and apparatus for performing said method
CN105411587A (zh) * 2015-12-07 2016-03-23 天津大学 用于人体胸腔电阻抗层析成像的胸腔轮廓数据采集方法
CN105411587B (zh) * 2015-12-07 2018-06-01 天津大学 用于人体胸腔电阻抗层析成像的胸腔轮廓数据采集方法

Also Published As

Publication number Publication date
DE1466785A1 (de) 1969-03-13
DK115486B (da) 1969-10-13
SE315070B (da) 1969-09-22

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