Multiple RF return pad contact detection system
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Accused Products
Abstract
A multiple RF return pad contact detection system is provided which is adaptive to different physiological characteristics of patients without being susceptible to electrosurgical current interference (e.g., interference or measurement interaction between components of the detection system). The detection system can measure or sense the contact resistance or impedance between the patient and pairs of RF return pads or return electrodes where multiple pairs of RF return pads are utilized due to the high current frequently needed during electrosurgery while eliminating or minimizing the risk of measurement interaction between the RF return pad pairs. The system allows for the independent and simultaneous measurement of the pad contact impedance for each pair of RF return pads. If the impedance of any pad pair is above a predetermined limit, the system turns off or reduces the electrosurgical output of the electrosurgical generator to prevent excess heating. The system eliminates or minimizes interference or measurement interaction between the pad pairs by providing a different signal source frequency for each pad contact pair, but a frequency which matches an associated series resonant network frequency. The current that flows in the series resonant network is a direct reflection or function of the pad impedance of the corresponding pad pair.
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Citations
36 Claims
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1-22. -22. (canceled)
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23. A method for adaptive impedance monitoring of at least one patient return pad configured for contacting a patient and transmitting electrosurgical energy back to an electrosurgical generator, the method comprising the steps of:
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selecting a desired impedance range having a lower limit and an upper limit;
recording impedance of at least one patient return pad to obtain an instantaneous impedance value;
determining whether the instantaneous impedance is within the impedance range;
updating the upper limit as a function of the instantaneous impedance value according to the determination of the determining step; and
monitoring the impedance of the at least one patient return pad to determine if the impedance is between the lower limit and the updated upper limit. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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30. An electrosurgical system comprising:
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an electrosurgical generator configured to generate electrosurgical energy, the electrosurgical generator coupled to least one patient return pad configured for contacting a patient and transmitting electrosurgical energy back to the electrosurgical generator;
an impedance measurement subsystem coupled to the at least one patient return pad and adapted to record impedance of at least one patient return pad to obtain an instantaneous impedance value; and
a microprocessor configured to;
select a desired impedance range having a lower limit and an upper limit;
update the upper limit as a function of the instantaneous impedance value according to the determination whether the instantaneous impedance is within the impedance range; and
monitor the impedance of the at least one patient return pad to determine if the impedance is between the lower limit and the updated upper limit. - View Dependent Claims (31, 32, 33, 34, 35, 36)
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Specification