Electric and magnetic fields created by electrosurgical units

One of the places where it is critical to prevent equipment malfunction due to electromagnetic interference is in the hospital operating room. Unfortunately, the electromagnetic environment in hospital operating rooms can be quite harsh. The electromagnetic fields present in this environment are created by distant sources such as AM and FM broadcast transmitting antennas as well as local sources such as electrosurgical units. Measured values are reported of electric and magnetic field strengths created by typical electrosurgical units. Measurements were taken in operating rooms at the Department of Veterans Affairs Medical Center in Fargo, ND, and were made for three electrosurgical units (ESU) operating modes. All three components of the electric and magnetic fields were determined as a function of frequency. Field strengths as large as 153 dB/spl mu/V/m and 76 dB/spl mu/A/m were measured 1 m from the electrosurgical unit.