Systems and methods for measuring tissue impedance through an electrosurgical cable
First Claim
1. An electrosurgical generator for delivering electrosurgical energy to a tissue via an electrosurgical cable and an electrosurgical instrument, the electrosurgical generator comprising:
- an output stage coupled to an electrical energy source and configured to generate the electrosurgical energy to the electrosurgical instrument;
a plurality of sensors configured to sense a voltage waveform and a current waveform of the electrosurgical energy; and
a controller configured to control the output stage to generate a desired level of the electrosurgical energy, the controller comprising;
a calculator configured to calculate a real part of an impedance based on the sensed voltage and current waveforms;
an impedance compensator configured to modify a target impedance profile using a solution to a quadratic equation that models reactive components of the electrosurgical cable; and
a control signal generator configured to generate a control signal to control the output stage so that the calculated real part of the impedance tracks the modified target impedance profile,wherein the solution to the quadratic equation is
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Abstract
The electrosurgical systems and methods of the present disclosure include a tissue resistance measurement system that compensates for capacitive parasitics in a cable connecting an electrosurgical generator to and electrosurgical cable to estimate the real resistance of a tissue load. The electrosurgical generator includes an output stage coupled to an electrical energy source and generates electrosurgical energy. The electrosurgical generator includes a plurality of sensors sensing a voltage and current of the electrosurgical energy and a controller controlling the output stage. The controller includes a calculator that calculates a real part of an impedance based on the sensed voltage and current, an estimator that estimates a resistance of the tissue using a solution to a quadratic equation that is a function of the real part of the impedance, and a control signal generator configured to generate a control signal for the output stage based on the resistance of the tissue.
1220 Citations
15 Claims
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1. An electrosurgical generator for delivering electrosurgical energy to a tissue via an electrosurgical cable and an electrosurgical instrument, the electrosurgical generator comprising:
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an output stage coupled to an electrical energy source and configured to generate the electrosurgical energy to the electrosurgical instrument; a plurality of sensors configured to sense a voltage waveform and a current waveform of the electrosurgical energy; and a controller configured to control the output stage to generate a desired level of the electrosurgical energy, the controller comprising; a calculator configured to calculate a real part of an impedance based on the sensed voltage and current waveforms; an impedance compensator configured to modify a target impedance profile using a solution to a quadratic equation that models reactive components of the electrosurgical cable; and a control signal generator configured to generate a control signal to control the output stage so that the calculated real part of the impedance tracks the modified target impedance profile, wherein the solution to the quadratic equation is - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of controlling an electrosurgical generator that delivers electrosurgical energy to a tissue via an electrosurgical cable and an electrosurgical instrument, the method comprising:
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sensing a voltage waveform and a current waveform of the electrosurgical energy; calculating a real part of an impedance based on the sensed voltage and current waveforms; modifying a target impedance profile using a solution to a quadratic equation that models reactive components of the electrosurgical cable; and generating a control signal to control an output from an output stage of the electrosurgical generator so that the calculated real part of the impedance tracks the modified target impedance profile, wherein the solution to the quadratic equation is - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A non-transitory computer-readable storage medium storing a program that, when executed by a processor, performs a method of controlling an electrosurgical generator that delivers electrosurgical energy to tissue via an electrosurgical cable and an electrosurgical instrument, the method comprising:
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sensing a voltage waveform and a current waveform of the electrosurgical energy; calculating a real part of an impedance based on the sensed voltage and current waveforms; modifying a target impedance profile using a solution to a quadratic equation that models reactive components of the electrosurgical cable; and generating a control signal to control an output from an output stage of the electrosurgical generator so that the calculated real part of the impedance tracks the modified target impedance profile, wherein the solution to the quadratic equation is
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Specification