CDRH receives many inquires from healthcare organizations, medical device manufacturers, clinicians, and the public seeking information about experiences with and prevention of electromagnetic interference (EMI) with medical devices. Of particular interest is the safe use of cellular and wireless communications equipment in the vicinity of medical devices. The following information is intended to help minimize the risks associated with medical device EMI and promote electromagnetic compatibility (EMC) in healthcare facilities.
CDRH EMC/EMI recommendations for healthcare facilities are as follows:
- Make use of available resources such as EMC professionals and publications and Internet web pages on the subject of medical device EMC;
- Assess the electromagnetic environment of the facility (e.g., identify radio transmitters in around the facility) and identify areas where critical medical devices are used (e.g., ER, ICU, CCU, NICU);
- Manage the electromagnetic environment, RF transmitters and all electrical and electronic equipment, including medical devices, to reduce the risk of medical device EMI and achieve EMC;
- Coordinate the purchase, installation, service, and management of all electrical and electronic equipment used in the facility to achieve EMC;
- Educate healthcare facility staff, contractors, visitors, and patients about EMC and EMI and how they can recognize medical device EMI and help minimize EMI risks;
- Establish and implement written policies and procedures that document the intentions and methods of the healthcare institution for reducing the risk of medical device EMI and achieving EMC;
- Report EMI problems to the FDA MedWatch program and communicate EMI/EMC experiences to colleagues in open forums such as medical/technical publications and conferences.
A comprehensive guidance document for EMC in healthcare facilities was developed, with CDRH participation, by the Association for the Advancement of Medical Instrumentation (AAMI):
Technical Information Report (TIR) 18, Guidance on Electromagnetic Compatibility of Medical Devices for Clinical/Biomedical Engineers. AAMI TIR 18-1997. Arlington, Virginia: Association for the Advancement of Medical Instrumentation; 1997.
See Electromagnetic Compatibility - Documents Available to Help Resolve Medical Device EMC Problems for a description of this document. To find out how to obtain AAMI TIR 18, go to the Standards Search page of the AAMI website and enter keyword "EMC."
For a better understanding of the concerns and issues of medical device EMI, particularly in healthcare institutions, CDRH recommends that AAMI TIR 18 be examined in its entirety. CDRH concurs with the summary recommendations that appear in AAMI TIR 18, which are reproduced below, and recommends that healthcare organizations consider them in reducing the risk of medical device EMI and achieving EMC in healthcare facilities.
Additional information and recommendations regarding medical device EMC in healthcare facilities can be found on the EMC pages of the CDRH website and the links that appear below. Of particular importance are the CDRH recommendations regarding medical telemetry, which were developed after TIR 18 was published.
Another important information resource for EMC assessment and management in healthcare facilities was developed by American National Standards Institute (ANSI) Accredited Committee C63 (EMC), also with CDRH participation:
ANSI C63.18-1997, Recommended practice for an on-site, ad hoc test method for estimating radiated electromagnetic immunity of medical devices to specific radio-frequency transmitters. New York: ANSI, 1997.
See Electromagnetic Compatibility - Documents Available to Help Resolve Medical Device EMC Problems for a description of this document. To find out how to obtain C63.18, go to http://shop.ieee.org/store/default.asp and search for product code SH94556
Association for the Advancement of Medical Instrumentation American Medical Association Council on Science and Public Health Electromagnetic Compatibility (EMC)
- ECRI - webpage
Guidance for Industry - Wireless Medical Telemetry Risks and Recommendations
- Medical Device Safety, Public Health Advisories, and Notices
- MedWatch- Safety Information and Adverse Event Reporting Program
Center for the Study of Wireless Electromagnetic Compatibility
- UK Medical Devices Agency "Mobile Communications - Summary"
AAMI TIR 18 Summary Recommendations
- Because of their responsibility for the safe functioning of patient care equipment, clinical/biomedical engineers should be the focal point for EMC, EMI mitigation, and EMC/EMI education/training within the health care organization.
- Purchase, installation, service, and management of all equipment (medical, communications, building systems, and information technology) used in the facility should be coordinated to assure EMC. Clinical/biomedical engineering, facility management, information systems, materials management, and risk management personnel should all be aware of the possibility for equipment interactions and the need for coordination.
- EMC/EMI should become a permanent responsibility of the health care organization's Safety Committee.
- Staff, visitors, and patients, including home-care patients, should be educated regarding the nature of EMI and how they can recognize and help prevent it.
- EMC should be considered in the site selection, design, construction, and layout of health care facilities.
- Clinical/biomedical engineers should work with facility management, telecommunications, information systems, materials management, and risk management personnel to manage the electromagnetic environment of the health care facility.
- The institution's administration or its designate, e.g., the Safety Committee, should promulgate policies and procedures that clearly set forth the intentions of the institution regarding management to achieve EMC including, among other things, the designation of areas of the facility where the use of common hand-held RF transmitters (e.g., cellular and PCS telephones, two-way radios) by staff, visitors, and/or patients is to be managed or restricted.
- Ad hoc radiated RF immunity testing should be considered when EMI is suspected, when RF transmitters are likely to operate in proximity to critical care medical devices, in prepurchase evaluation of new types of RF transmitters to determine their effect on existing medical devices, in prepurchase evaluation of new electronic medical devices, and when checking for age-related changes in medical device RF immunity. Ad hoc testing can be used to estimate the minimum distance that should be maintained between a specific RF transmitter and a specific medical device to mitigate EMI. Policies and procedures for EMI mitigation should be based on objective information, such as that obtainable by ad hoc RF immunity testing.
- RF transmitters purchased for use in the facility should have the lowest possible output power rating that can be used to accomplish the intended purpose.
- Electrically-powered medical devices purchased for use in the facility should meet EMC standards.
- Electronic medical devices used in intense electromagnetic environments, such as near ambulance radios or in electrosurgery, should have EMC specifications suitable for these environments.
- Clinical/biomedical engineers should consider tracking "no problem found" service calls by the location, date, and time of the reported malfunction. This can help associate malfunctions with sources of electromagnetic disturbance (EMD).
- EMI problems should be reported to the manufacturer and to regulatory authorities.
- The health care organization may want to consider obtaining the services of an EMC professional for assistance in characterizing the electromagnetic environment, solving specific problems, and/or educating staff.
Adapted from Association for the Advancement of Medical Instrumentation. Guidance on Electromagnetic Compatibility of Medical Devices for Clinical/Biomedical Engineers. AAMI TIR 18-1997. Arlington, Virginia: Association for the Advancement of Medical Instrumentation; 1997.