The News Room

It seems like a normal situation. A doctor making rounds in a hospital intensive care unit (ICU) leans against a bedside table that has a telemetry transmitter. The doctor’s mobile phone rings, subsequently causing the telemetry transmitter to lose its signal and inadvertently interfere with the entire ICU telemetry system.

An updated technical information report (TIR) developed by the Association for the Advancement of Medical Instrumentation (AAMI) offers guidance on how to prevent this and other instances of electromagnetic interference (EMI) of medical devices and systems. The report, ANSI/AAMI TIR18: 2010, Guidance on electromagnetic compatibility of medical devices in healthcare facilities, includes a template for a wireless and electromagnetic compatibility (EMC) policy. It also offers recommendations on ad-hoc testing of devices to estimate their immunity to EMI.

The TIR is primarily geared toward clinical and biomedical engineers to help them assess the electromagnetic environment in their facility and implement actions that minimize electromagnetic interference (EMI) problems. The new edition also has been rearranged to make it easier for non-engineers to find and understand recommendations.

“We are also trying to reach the hospital administrators because they make all the decisions on resources, and it is important that resources be allocated to this activity,” says Jeffrey Silberberg, a senior electronics engineer for the U.S. Food and Drug Administration (FDA), and a member of the AAMI Electromagnetic Compatibility Committee, which drafted the TIR.

The updated TIR contains new information on development of a wireless/EMC policy for a healthcare facility. A model policy will help to mitigate risks associated with medical device EMI and to address the use of radio frequency (RF) wireless technology, according to the TIR.

The model EMC and RF wireless policy is organized into six sections in the TIR: purpose, applicability, responsibilities, abbreviations and definitions, EMI mitigation and EMC management, and references.

A policy tailored for a specific institution should include examples of the problems that could arise from medical device EMI and RF wireless and why they are important, according to the TIR.

Designating a Coordinator

A key recommendation in the TIR focuses on the designation of an EMC/wireless coordinator to help manage medical devices for EMC. “The potential for EMI problems can be reduced through pre-purchase assessment or evaluation of new devices and proper evaluation, maintenance, and management of existing devices,” the TIR states.

The EMC/wireless coordinator would be involved with purchasing equipment and coordinating with biomedical/clinical engineering departments, information technology (IT), medical staff, and others to determine whether the equipment complies with hospital standards and policies regarding EMC. “It is nice to get equipment that is more immune to electromagnetic disturbances,” says Silberberg.

Another option for measuring devices’ immunity is ad-hoc testing, which estimates the RF immunity of medical devices to specific RF transmitters, according to the TIR. Ad-hoc testing should be used in certain instances, such as investigating EMI incidents and when the electromagnetic immunity of a device is unknown. The TIR points readers to the recommended practice for ad hoc RF immunity testing, ANSI/IEEE C63.18:1997.

Founded in 1967, the Association for the Advancement of Medical Instrumentation (AAMI) is a nonprofit organization representing a unique alliance of nearly 6,000 members from around the world united by one mission — to increase the understanding and beneficial use of medical instrumentation through effective standards and educational programs, and publications.