Valleylab, Inc.

Covidien Ag

William G Paterson

David W Newton

Michael S Klicek

Derek M Blaha

An electrosurgical generator is provided which includes a continuity test circuit assembly for testing electrical continuity through an electrode of an electrosurgical instrument. The continuity test circuit assembly includes a test power source providing electrical test energy to a first conductor which is in electrical communication with the electrode and the electrosurgical generator and to at least one second conductor which is coupled to the first conductor for providing a path for current to flow between the first conductor and the at least one second conductor for establishing a test path through which the test energy flows between the first conductor and at least one conductor of the at least one second conductor. The continuity test circuit assembly further includes energy detection circuitry positioned along the test path for detecting the flow of the test energy through the test path for determining electrical continuity through the electrode.

Method and system for continuity testing of medical electrodes

A power control apparatus for an electrosurgical generator is used for controlling output power from the generator to the tissue or bodily fluids of a patient. The control apparatus rapidly determines the range of impedance of the load on the electrosurgical generator and adjusts the output power accordingly. Output current and output voltage from the electrosurgical generator are monitored and sent to a microprocessor. The microprocessor runs an algorithm that determines the impedance range of the load on the generator. The algorithm uses computational techniques, such as comparisons and bit shifting, that avoid long division and other time-consuming operations. The microprocessor can then adjust a high voltage power supply that effects the radio frequency amplifier stage. A method for controlling the power of the electrosurgical generator, including steps in the algorithm, is also disclosed.

Control apparatus for electrosurgical generator power output

Apparatus and method find leakage due to tissue load or transients and has active and return electrodes for RF energy sensed by transformers for a circuit that finds leakage at more than two thousand times per second or a frequency dependent on the phase shift between voltage and current. Software and feedback manage V.sub.rms to reduce the voltage or increase the crest factor, which is V.sub.rms divided by peak voltage, by pulse width modulation of the RF drive. Voltage and current phase shift changes, angle .theta., are compared to a threshold, and when greater, the frequency at which the differences between the active and return current signals are examined is increased. The differences between the active and return currents are examined and when greater than maximum leakage while in coagulation mode, the RF drive pulse width is reduced to maintain voltage wave peaks at a preset value and reduce V.sub.rms thereby reducing leakage to the allowable maximum. Reducing the duty cycle or the pulse width of the output wave increases the crest factor. When the differences between active and return currents are greater than a maximum for leakage while in cut or bipolar mode, the V.sub.rms is reduced to limit leakage to a maximum level. When the phase angle .theta. is less than a threshold, the frequency with which leakage is examined is reduced.

Apparatus for leakage control and method for its use

An electrosurgical generating system including an electrosurgical generator; a handpiece including an active electrode connected to the generator for applying electrosurgical current from the generator to a patient; and an initializing device or circuit for making an initial determination as to whether the handpiece includes power changing switches for changing the level of the output power delivered from the generator to the patient. Assuming the handpiece does include such switches, circuitry is also disclosed for limiting the amount the power can be increased or decreased from the handpiece. Also circuitry is disclosed for effecting the power increase or decrease in incremental steps.

Circuitry for processing requests made from the sterile field of a

A return electrode monitoring system for use with a split patient return electrode having two, electrically isolated electrode elements adapted for contacting a patient, the system comprising means responsive to the impedance between the two electrode elements for producing a signal which is a function of the impedance; means for establishing a desired range having an upper limit and a lower limit for the impedance when the patient is in contact with the electrode elements; determining means responsive to the signal for determining whether the impedance is within the desired range; and adjusting means for adjusting the upper limit to adapt the system to the particular impedance of the patient in response to the particular impedance occurring within the desired range.

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Longmont, CO, United States of America

William G Paterson