Electrosurgical safety circuit and method of using same

摘要

An improved electrosurgical safety circuit where the currents in the active and patient leads are monitored, the monitored currents being respectively rectified and then subtracted from one another. Whenever the active current exceeds the patient or return current by an amount corresponding to a dynamically variable threshold, an appropriate measure is taken such as the sounding of an alarm and/or the de-energization of the electrosurgical generator. The dynamic threshold varies in accordance with the level of the signal applied to the patient and compensates for leakage current through stray capacitance from the active lead to ground.