Power control for beam-type electrosurgical unit
AssigneeC. R. Bard, Inc.
InventorCarol Bertrand
Life of this patent
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Abstract
An electrosurgical generator in an electrosurgical unit (ESU) controls the repetition rate and the energy content of bursts of RF energy delivered to a gas jet supplied by the ESU, in order to maintain RF leakage current within acceptable limits while still achieving a sufficient state of ionization in the gas jet to reliably initiate the conduction of arcs to the tissue. The repetition rate of the RF bursts is substantially reduced in an inactive state when no arcs are delivered. A relatively small number of the RF bursts delivered during the inactive state have an increased or boosted energy content to assure an adequate ionization state in the gas jet.
Claims21
In an electrosurgical unit which includes means for conducting a predetermined gas in a jet to tissue and means for transferring electrical energy in ionized conductive pathways in the gas jet, said electrical energy transferring means operatively transferring arcs to the tissue in the ionized conductive pathways in an active state to thereby create a predetermined electrosurgical effect on the tissue, said electrical energy transferring means operatively creating substantially only ionized conductive pathways in the gas jet in an inactive state to allow arc initiation upon transition to the active state, said electrical energy transferring means including electrosurgical generator means for generating target bursts of radio frequency electrical energy at a predetermined inactive repetition rate in the inactive state and for generating active bursts of radio frequency electrical energy at a predetermined active repetition rate in the active state, said electrical energy transferring means applying the bursts of radio frequency energy to the gas jet, and an improvement to said electrosurgical generator means comprising, in combination:
- repetition rate changing means for changing the predetermined repetition rate of the target bursts to a value substantially less than the predetermined repetition rate of the active bursts.
In an electrosurgical unit which includes means for conducting a predetermined gas in a jet to tissue and means for transferring electrical energy in ionized conductive pathways in the gas jet, said electrical energy transferring means operatively transferring arcs to the tissue in the ionized conductive pathways in an active state to thereby create a predetermined electrosurgical effect on the tissue, said electrical energy transferring means operatively creating substantially only ionized conductive pathways in the gas jet in an inactive state to allow arc initiation upon transition to the active state, said electrical energy transferring means including electrosurgical generator means for generating target bursts of radio frequency electrical energy at a predetermined repetition rate in the inactive state and for generating active bursts of radio frequency electrical energy at a predetermined repetition rate in the active state, said electrical energy transferring means applying the bursts of radio frequency energy to the gas jet, and an improvement to said electrosurgical generator means comprising, in combination:
- means for generating the target bursts in a plurality of repeating sequences during the inactive state, each sequence including a plurality of target bursts;
- and
- booster means for substantially increasing the energy content of a predetermined plurality less than all of the target bursts occurring during each sequence, those target bursts of increased energy being booster target bursts and those other target bursts being normal target bursts.
Dependencies are inferred from the claim text.