Claims
- 1. A method of determining the amount of skin contact between a biomedical electrode and skin of a patient, comprising the steps of:(a) measuring change of phase angle over change in time (δΘ/δt) of an energized biomedical electrode in contact with a patient's skin; wherein the measuring step uses the equation: ΘTotal=[θLossy Dielectric*(AreaLossy Dielectroc/AreaTotal )]+[ΘBare Metal*(AreaBare Metal/AreaTotal)]; and (b) sounding an alarm when δΘ/δt exceeds a predetermined amount; δΘ/δt being indicative of the amount of skin contact between a biomedical electrode and the patient's skin.
- 2. The method of claim 1, wherein the measuring step uses software, hardware, or both to achieve a monitoring of phase angles of current flow of various portions of the energized biomedical electrode connected to both biomedical instrumentation and the skin of a patient.
- 3. The method of claim 2, wherein the measuring step uses software including an A/D conversion algorithm measurement wherein the maximum sample period is given by the equation:Ts,max(1/ν)/(360°/Θ).
- 4. The method of claim 3, wherein the phase angle is represented by the equation:phase=Θ=Q−F=tan−1{IM(vcauterize(n))RE(vcauterize(n)}where IM (.) is the imaginary component and RE(.) is the real component of the discrete time cauterizing signal, vcauteize(n).
- 5. The method of claim 2, wherein the measuring step uses hardware circuitry.
- 6. The method of claim 5, wherein the hardware circuitry multiplies two signals to yield the following equation:Θ=Q−F=cos−1[2 LP{vsource(t)vcauterize(t)}/VsourceVcauterize)], wherein Q is the x intercept of electrical wave (E) and F is the x intercept of the corresponding magnetic wave (M) orthogonal to the electrical wave; wherein LP{vsource(t) vcauterize(t)} is an amount using a low pass filter of the two signals vsource(t) vcauterize(t) being multiplied and (Vsource Vcauterize) are known values of the voltages of the source signal and the cauterizing signal.
- 7. The method of claim 5, wherein the hardware circuitry is a phase locked loop device.
- 8. The method of claim 5, wherein the hardware circuitry is a zero-crossing detector.
- 9. The method of claim 5, wherein the hardware circuitry measures time difference using an integration of a resistor/capacitor circuit using the following equation:VRC=∫vand(t) wherein the equation uses zero crossing signals into a fast AND gate which drives a parallel resistor and capacitor.
- 10. The method of claim 1, wherein the alarm is visible or audible.
- 11. The method of claim 10, wherein the alarm is electrically connected to biomedical instrumentation that drives electrosurgery.
- 12. An apparatus for detecting loss of contact between a biomedical electrode and skin of a patient, comprising:(a) a biomedical electrode having an electrical conductor wherein at least a portion thereof has a layer of lossy dielectric material in electrical contact with both biomedical instrumentation and the skin of a patient; and (b) means for detecting when a change in phase angle over change in time (δΘ/δt) exceeds a predetermined amount; wherein the means for detecting is electrically connected to the biomedical electrode: and wherein means for detecting uses the equation: ΘTotal=[ΘLossy Dielectric*(AreaLossy Dielectric/AreaTotal)]+[ΘBare Metal*(AreaBare Metal/AreaTotal)] to sound an alarm when δΘ/δt exceeds the predetermined amount; and wherein δΘ/δt uses voltage signals of a source signal vsource and a cauterizing signal vcauterize.
- 13. The apparatus of claim 12, wherein the biomedical electrode has a body contact portion that includes the electrical conductor and the layer of lossy dielectric; andwherein the electrical conductor comprises at least two conductor plates.
- 14. The apparatus of claim 12, wherein each of the at least two conductor plates has an extended tab extending away from the body contact portion.
- 15. The apparatus of claim 13, wherein the body contact portion further comprises a field of pressure sensitive adhesive.
- 16. The apparatus of claim 15, wherein the field of pressure sensitive adhesive is ionically conductive.
- 17. The apparatus of claim 13, wherein the at least two conductor plates have interior edges having curvilinear geometries relative to a longitudinal axis of the biomedical electrode.
- 18. The apparatus of claim 13, wherein the at least two conductor plates are made from metal-containing or graphic-containing coated ink or paint.
- 19. The apparatus of claim 13, wherein the layer of lossy dielectric material occupies an area of the body contact portion ranging from about 5% to about 70% defining an area percentage and wherein the area percentage determines two variable in the equation.
- 20. The apparatus of claim 17, wherein the layer of lossy dielectric material is applied in a non-uniform thickness to result in an electrical impedance gradient from the interior edge to an exterior edge of the body contact portion ranging from about 30% to about 90% of the maximum impedance at the exterior edge of the body contact portion.
Parent Case Info
This application is a continuation in part of Ser. No. 08/832,835 filed Apr. 4, 1997 now abandoned.
US Referenced Citations (23)
Foreign Referenced Citations (4)
Number |
Date |
Country |
32 06 947A |
Sep 1983 |
DE |
2 516 782 |
May 1983 |
FR |
WO 8101954 |
Jul 1981 |
WO |
WO 9619152 |
Jun 1996 |
WO |
Non-Patent Literature Citations (1)
Entry |
Derwent Abstract for FR 2 516 782 A. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
08/832835 |
Apr 1997 |
US |
Child |
09/256022 |
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US |