Measurement of electromagnetic field strengths in urban and suburban hospital operating rooms

Measurements of radiated electromagnetic (EM) fields were performed in 14 operating rooms (ORs) in two hospitals, one urban and one suburban. A broadband electromagnetic field measurement system with a data-logger was used to measure the electric field strength. In four of the ORs, no surgery was taking place so only the ambient field was measured and was found to be <0.2 V/m. Data from the other nine ORs show ambient fields as high as 0.8 V/m in the urban hospital and source levels exceeding 30 V/m near electrosurgical units (ESUs). These levels exist at locations where other critical medical devices were seen to be located and represent levels of EM energy to which devices must be immune if they are to perform without electromagnetic interference (EMI) problems.