The Blindspot of Electromagnetic Interference Affecting Sensitive Medical Devices at Hospitals and Healthcare Facilities

Abstract

Electromagnetic interference (EMI) can affect a hospital's sensitive medical equipment when the EMI is powerful enough and close enough to cause partial or complete failure of the equipment or its sub systems. Particularly amidst a lack of EMI shielding, the closer in proximity the EMI is to susceptible medical equipment, the chance of interference grows and is more likely to occur. Failure of critical electronic medical equipment can be life-threatening and should be prevented whenever possible. Power recycling/re-calibration time can be a lengthy process, so EMI should be mitigated to the maximum extent possible. The adverse impact of EMI, as pertains to sensitive medical devices, may only be transient in some instances, but it may also have profound impact leading to patient injury. True EMI immunity can only be ascertained by careful measurement and testing, and this is usually not performed routinely as hospitals and healthcare facilities have rapidly expanded. Indeed, while alternate current (AC) powerline EMI filters may be commonly employed, oftentimes what is in plain sight is overlooked — that of “noise” from a direct current (DC) source from a nearby instrument transformer, disconnecting switch, and similar components. The National Institutes of Health (NIH) have reported that several medical-related devices have had operational issues due to radiofrequency interference (RFI), particularly as pertains to super low frequency (SLF) (in the frequency range of 30 Hz up to 300 Hz), such as for power grids.