US 2895479 A
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Description (OCR text may contain errors)
R. A. LLOYD` ELECTROCARDIOGRARH ELECTRODE July 21, 1959 Filed Sept. 13, 1957 iff" INVENTOR A. LLOYD Attorney ROGER United States Patent O sclims. (cl.- 412s- 417) l 1 .ff
This invention relates to a new electrode comprising a portion of an electrocardiograph or other instrument comprising one or more electrodes which establish contact with the epidermis and more particularly it relates to such an electrode comprising a sintered porous metallic disc.
s Heretofore it has not been Iunusual for electrocardiograph electrodes to give inaccurate ahd'inconsistentreadings due to changes in the conductance of the electrode. Such inaccuracy and inconsistency of results obtained with prior electrocardiograph electrodes has been caused in part by the depletion of the conductive material or solution and in part by the conductive material or solution not providing good contact between electrode and patient. Also in many prior electrocardiograph electrodes, conductive salts and salt solutions have been prepared as pastes or liquid solutions and have been applied to an area of the patients skin on which the electrode was to be placed. Application of such conductive salts as pastes or as liquid salt solutions has not been conducive to restricted area testing because the pastes and liquid salt solutions could not be limited to the area in which the electrode contacted the patient. Pastes and liquid salt solutions also have dried out before completion of tests and by such drying out have caused lowering of conductance and inaccuracy in the nal report.
Another disadvantage of prior electrocardiograph electrodes has been the poor means of attachment between electrode and cable which in turn has caused the electrode to give inaccurate test results and has also caused the electrode to be detached from the cable and damaged or lost during transfer of the electrocariograph from one part of a hospital or clinic to another.
In addition to being part of an electrocardiograph, my electrode may be part of any other instrument which comprises one or more electrodes which are used to establish electrical contact with a polygraph (lie detector) or electrotherapeutical apparatus.
It is therefore an object of my invention to provide an electrocardiograph electrode which has uniform conductance and retains continuous uniform conductance over long periods of sustained use.
Another object is to provide an electrocardiograph electrode which gives consistent and accurate testing results.
Another object is to provide an electrocardiograph electrode which contains a reserve supply of conductive solution which does not dry out and which does not need to be replenished over long period of use such as, for exple, during use in major heart and brain surgery.
Another object is to provide an electrocardiograph electrode which gives good contact between electrode and patient and also provides a test area which is limited to the electrode contact for restricted area testing.
Another object is to provide an electrocardiograph electrode which does not require a conductive paste or other accessory and thereby require extra expense and a cleanup operation.
Another object is to provide an electrocardiograph'elecftrode which is permanently attached to the cable of the `electrocardiograph and which therefore can not be lost or misplaced during transfer of the electrocardiograph.
Another object is to provide an electrocardiograph elecl l trode which is unbreakable, streamlined. and permanent.
Another object is to provide an electrode for an electrocardiograph which requires no separate action of application of the electrolyte to the testing surface of the `patients body and which does not cause undue mental distress to the patient nor staining of the clothing.
Another object is to provide an electrodefor an electrocardiograph with which accurate results can be obtained by relatively inexperienced operators.
Other objects will become apparent from the drawings and from the following detailed description in which it is "intended to illustrate the applicability of the invention `without thereby limiting it to a scope less than that of all equivalents which will be apparent to one skilled in the art. In the drawings `-like parts and;
f "Figure l isa graph electrode;
`like reference numerals refer to `sectional elevation'of the electrocardio- Figure 2 is a perspective view of the embodiment of Figure l;
Figure 3 is a sectional elevation of another embodiment of my invention.
Referring now more particularly to the drawings, reference numeral 1 is the main body of my electrode; the lower portion of said body 1 encloses a sintered or porous metal disc 2 which constitutes the base of said electrode. Housing 1 or 1 is conductively attached to disc 2 as by soldering or swaging and provides reservoir 3 immediately above said disc. Immediately above disc 2, housing 1 or 1' is provided with a hole to receive a cable jack adapter 4 or conductor such as wire 17 (Figure 1) respectively. Cable jack 5 may be soldered into the cable jack adapter 4; however a thumbscrew 6 may be used as an alternative as shown. Conductor 17 is irremovably attached to housing 1 by suitable means such as solder 18. Attached to and perpeidcular to the upper surface of the body 1 of my electrode is a stem 7 or holder 9; depend ing on the particular embodiment, said stem or holder may be attached to the body 1 by solder or by screw means 10 or by other suitable means such as swaging, staking or riveting.
The reservoir 3 of my electrode is filled by means ot a hypodermic syringe, or other suitable means, at the lling hole 12 or 13, depending on the model. In the embodiment of Figures 1 and 2 the lling hole 12 is located on the axis of stem of the electrode and in the embodiment of Figure 3 the filling hole 13 extends through the upper portion of the body 1 of the electrode. The filling hole 12 of the embodiment of' Figures 1 and 2 must be located on the axis of stem 7 of the electrode because this specific embodiment is used to make tests by placing the electrode on the limb of the patient. The electrode is attached to the limb 8 of a patient by a rubber or plastic strap 11, said strap 11 containing holes 15 in each end. The stem 7 of my electrode is placed through one of the holes 15 in one end of the said strap 11 and the other end of said strap 11 is extended around said limb 8 until said extended end of said strap extends over stem 7; stem 7 is then placed in the hole 15 which best provides a tight contact for my electrode against the limb 8 of the patient. The reservoir 3 may be lled while the device is in use and attached to a patient. It may be filled with tap water, or if preferred various other water soluble electrolytes, skin irritants to lower skin resistance, penetrating agents, detergents, surface active agents or the like may be added to the water to lower its resistance and improve its skin contact. The Water or aqueoussolution,diffusesthrough the sintere'dconductive Y- The body 1 ofmy nev/ and unique .electrocardiograph electrode may beconstructedof stainless steel, aluminum bronze or vany other metal which lends itself to the con- ,structionlof such ,an article. The sintered conductive dise 2, however, kis lconstructed of a highly conductive material and While other Ymaterials are .operable, `the preferred vmaterial-is ahighlyconductive metal such :as ,silver., platinum, stainless steel, bronze orcopper.
kI f desired, the klower .surfaces of disc,.2 may berough as shown in Figure ,1. l,Such roughness ,makes'it easy to ,mildly Iirritate the patients Yskin by lightly vrubbing or l rotating the electrodewhen Aputting it in-placeg this has beenfound to have the 'desirable effect of markedly infcreasing conductance.
While certain modifications and embodiments of `the rinvention have been described, it is of courseto be understood that there are a great number of variations which suggest themselves @to .anyone familiar with the subject matter thereof and it is distinctly understood that this `invention should `'not -be limited except "by such limitations as are clearly imposed in the appended claims.
1. A device of the type described comprising a disc of sintered conductive material, said disc being impregnated with a liquid electrolyte, a metal housing in conductive relation to said disc, said housing providing a reservoir above said disc for said electrolyte, and electrical conductor means attached "to sai'd'housing.
2. Theglevice-of .gclairn V,1:fu1'ther characterized by said disc being of stainless steel.
3. The device /of'claimd further'characterized by said electrolyte Abeing :tap water.`
4. The device of claim l further characterized by said housing being provided -with .la singleupward'ly extending tube having a bore which provides means for introducing said electrolyte into said reservoir and provides means for attaching the device to a patient.
15. The devieepf claim 1 provided with electrically conductive means .,-irremovably attached to Isaid housing.
References .Cited in the le of this patent LUNITED STATES PATENTS