Mobile telephones interfere with medical electrical equipment

Electromagnetic interference in medical electrical equipment has not been a serious problem in recent years even with the proliferation of analogue mobile phones and two-way handheld radios. With the introduction of GSM digital mobile phones into Australia we have conducted measurements and found that, within 2m, the electric fields from digital mobile phones can exceed the immunity level of 7 V/m recommended by the US Food and Drug Administration (FDA) for medical electrical equipment. Current analogue mobile phones were shown to produce electric fields that exceed the 7 V/m level only at relatively shorter distances. In another test, both analogue and digital mobile phones were operated close to a range of typical medical electrical equipment. It was found that existing equipment generally meets the FDA standard, but digital mobile phones caused a variety of artefacts and alarm conditions. This problem must be addressed by the medical engineering profession; in the meantime, nursing and other staff should be educated to recognise these problems and restrictions must be placed upon the use of mobile phones in hospitals.