Low cost system to measure active power in electrosurgical units

José Flavio Dums; Bertoldo Schneider Junior; Alceu André Badin

doi:10.1590/2446-4740.03217

Original Article

Low cost system to measure active power in electrosurgical units

José Flavio Dums; Bertoldo Schneider Junior; Alceu André Badin

http://dx.doi.org/10.1590/2446-4740.03217 Res. Biomed. Eng., vol.33, n4, p.313-323, 2017

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Abstract

Abstract Introduction: The real-time measurement of active power delivered to patients during the electrosurgical act is still an engineering challenge. Besides, there is no electrosurgical unit on the market capable of doing it according to the normative requirement.

Methods: This work presents the design of an electronic structure capable to probe the electrosurgical equipment output electrical signals, using low-costs very common resistors, and High Frequency distortions compensation circuits, and process them to provide an analogue signal proportional to the active power, allowing the knowledge and control of the energy delivered to the biological tissue. The reading circuits and the active power calculation method are presented. The power calculation is performed in two stages. The first one consists of a multiplier circuit that uses the readings voltage and current quantities to determine the instantaneous output power, and the second stage is formed by an integrating circuit which determines the average power value, resulting in a rippled continuous voltage, proportional to the active power delivered to the patient or biological tissue.

Results: Practical tests of the compensation technical are statistically evaluated by means of linear regressions. Results of 23 tests are summarized in a way to demonstrate de effectiveness of the proposed system.

Conclusion: Analysis of the results demonstrate the efficiency of the proposed system, whose average error is lower than 5%, and correlating them with the standard IEC 60601-2-2, that regulates the operation of electrosurgery units.

Keywords

Electrosurgery, Active power, Analogue multiplier, Analogue integrator, HF current probing, HF voltage probing

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Low cost system to measure active power in electrosurgical units

José Flavio Dums; Bertoldo Schneider Junior; Alceu André Badin

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