RF Exposure During Use of Electrosurgical Units

Liljestrand B, Sandström M, Hansson Mild K.

Electromag. Biol. Med. 22:129-132, 2003

Electrosurgical units (ESUs) commonly used in operating suites employ radiofrequency (RF) energy for cutting and coagulation, and operate at different frequencies in the range 0.3­5 MHz. Around the electrode and cables, electric and magnetic fields at similar frequencies will be generated, and the surgeon using the ESU will therefore be exposed to these electromagnetic fields.

In this study we have measured the levels of RF fields near the lead wires of two electrosurgical units, BARD 3000 operating at a fixed frequency of 0.5 MHz, and ERBE ICC 350 with a frequency range from 0.3 to 1 MHz. Electric fields were measured at distances from 5­30 cm from the lead wire.

Measurements were done with the ESU both cutting and coagulating, and power levels ranging from 10­100 W. The magnetic field outside the lead wire was calculated from the measured current through the leads using standard theory. Using those measurements as a base, the calculated local exposure of the surgeon's hand was estimated to exceed 15 kV/m for the electric field and the corresponding value for the magnetic field was 16 µT.

These calculations exceed the suggested international reference levels at 0.5 MHz (610 V/m and 4 µT, respectively).