GUIDE TO INSPECTIONS OF ELECTROMAGNETIC
COMPATIBILITY ASPECTS OF MEDICAL DEVICE
21 CFR 820.200(c) Determining MDR-reportable Service Reports
Any service report that represents an EMI event which must be reported to FDA under parts 803 or 804 of the MDR regulation should automatically be considered a complaint and have appropriate follow-up under the requirements of 21 CFR 820.198.
21 CFR 820.200(d) Documentation of Service Reports
Service reports for potential EMI problems should be documented by the firm in accordance with the Quality System regulations.
21 CFR 820.100(a) Corrective and Preventive Actions
For electrically powered devices in production, the manufacturer should be analyzing its quality problem information (e.g. complaints, field service reports, etc.), for potential EMI problems.
The firm should consider whether its electrically-powered device (e.g. powered wheelchair, ventilator, apnea monitor, ECG monitor, hearing aid, etc..) is vulnerable to different forms of electromagnetic energy which could cause EMI (e.g. static, radio frequency transmissions) and/or whether it emits electromagnetic energy which could cause interference in other devices (e.g. electrosurgical unit, telemetry transceiver, device controllers). Some devices can be both a source and a "receiver" of EMI, depending on the environment in which they are used (e.g. telemetry devices). Devices which commonly fall prey to EMI are telemetry based devices and devices with microcircuitry (including microprocessors), particularly devices that have inadequate shielding and/or filtering. Offending RF sources are often RF equipment.
The firm should look for trends in its quality problem information which would identify erratic, unexpected behavior of its therapeutic devices (e.g. wheelchairs moving without user command; sudden irregular pacing of a pacemaker) or inexplicable inconsistencies between a patient's condition and the expected output of its diagnostic device (e.g. inexplicable or "noisy" waveforms, alarms not activating in an alarm condition or vice versa). (See Appendix D for a list of key words to look for in complaint records.)
A firm should be aware that device malfunctions that seem to "self-resolve" or which cannot be reproduced when removed from the environment in which it malfunctioned could be attributable to EMI and should not be disregarded.
The firm should assess whether EMI could be a potential cause of nonconformance. Events that appear to be EMI-related can sometimes be attributed to causes other than EMI (e.g. poor circuit design, poor selection of components, software bug, component failure intermittent connection, user error). However, the firm should not automatically rule out EMI as a cause of a potential problem unless it can be attributed to another cause.
The firm should try to determine the environment in which the device was used when the problem occurred. Note that the actual environment may differ from the firm's idea of the intended use environment. A firm may shield a device from certain emissions, believing that the device is protected. It may find that the device is not protected because its design was based on incorrect environmental use assumptions.
Example: A powered wheelchair firm may not presume in its design that a user would live near high power transmission lines or television broadcast antennas, but the same firm may have designed for immunity to personal communications systems output since this would be commonly found in the use environment.
There will be occasions when EMI is difficult if
- Analyzing Quality Problem Information
- Investigating or Determining the Cause