US6258085B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrosurgical return electrode monitor
Assignee: Covidien AG
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Filing: 1999-05-11
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Granted: 2001-07-10
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Expires: 2019-05-11
Abstract
Abstract The present disclosure provides a method for determining the probability of a patient burn under a return electrode in a momopolar electrosurgical system comprising calculating a heating factor adjacent the return electrode utilizing a first algorithm, calculating a cooling factor adjacent the return electrode utilizing a second algorithm, subtracting the calculated cooling factor from the calculated heating factor to obtain a difference value, comparing the difference value to a threshold value, and adjusting the power dependent on the relationship of the difference value to the threshold value.
Inventors
- 👤 Jeffrey L. Eggleston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:08
CPC Classifications
A; A61; A61B; A61B18/00; A61B18/04; A61B18/12; A61B18/1206; A61B18/1233; A61B18/14; A61B18/16
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
127 words
An electrosurgical system comprising: an electrosurgical generator having an electrosurgical tool for treating tissue, a return electrode, and an impedance sensor in electrical communication with the return electrode to measure impedance of the return electrode, wherein said electrosurgical generator further comprises: a current sensor for measuring an output current delivered by the electrosurgical generator; a microprocessor electrically connected to the current sensor and the impedance sensor for calculating a heating factor and a cooling factor of the tissue under the return electrode, the calculation of the heating factor being based at least in part on the measured output current; and a controller electrically connected to the microprocessor for adjusting a power supply of the generator in response to a relationship of the calculated heating and cooling factors.
Claim 2
Dependent Claim
127 words
An electrosurgical system comprising: an electrosurgical generator having an electrosurgical tool for treating tissue, a return electrode, and an impedance sensor in electrical communication with the return electrode to measure impedance of the return electrode, wherein said electrosurgical generator further comprises: a current sensor for measuring an output current delivered by the electrosurgical generator; a microprocessor electrically connected to the current sensor and the impedance sensor for calculating a heating factor and a cooling factor of the tissue under the return electrode, the calculation of the heating factor being based at least in part on the measured output current; and a controller electrically connected to the microprocessor for adjusting a power supply of the generator in response to a relationship of the calculated heating and cooling factors.
Claim 3
Dependent Claim
27 words
The generator of claim 1 , wherein the microprocessor includes a first algorithm for calculating the heating factor and a second algorithm for calculating the cooling factor.
Claim 4
Dependent Claim
55 words
The generator of claim 2 , wherein the second algorithm is defined as k c t off wherein K c is a constant representative of the time it takes for the tissue to cool down in degrees per minute and t off is the time in seconds that the output current is not being delivered.
Claim 5
Dependent Claim
62 words
The generator of claim 2 , wherein the first algorithm is defined as k h I 2 t on wherein K h is a constant representative of a measured impedance in Ohms of the return electrode, I 2 is the square of said measured output current in milliamps and t on is the time in seconds that the output current is delivered.
Claim 6
Dependent Claim
24 words
The generator of claim 4 , wherein the measured impedance is indicative of the degree of adherence to the tissue of the return electrode.
Claim 7
Dependent Claim
73 words
The electrosurgical generator of claim 1 , wherein the microprocessor includes an algorithm for subtracting the cooling factor from the heating factor to calculate a difference value, and the generator further comprises a comparator electrically connected to the microprocessor for comparing the difference value to a threshold value, the comparator being electrically connected to the controller to generate a first signal indicative of the relationship of the difference value and the threshold value.
Claim 8
Dependent Claim
33 words
The electrosurgical generator of claim 6 , further comprising an alarm electrically connected to the comparator for generating a warning signal if the difference value exceeds the threshold value by a predetermined amount.
Claim 9
Dependent Claim
35 words
The electrosurgical generator of claim 6 , wherein the controller generates a shut off signal to terminate power if the difference value exceeds a predetermined value, the predetermined value being greater than the threshold value.
Claim 10
Dependent Claim
33 words
The electrosurgical generator of claim 8 , wherein the controller generates a second signal to reduce the power if the difference value exceeds the threshold value but does not exceed the predetermined value.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-07-09 | 2005-01-08 | 2005-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-07-09 | 2009-01-08 | 2009-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-07-09 | 2013-01-08 | 2013-07-10 | $7700.00 | Window Closed / Lapsed |