GUIDE TO INSPECTIONS OF ELECTROMAGNETIC...F MEDICAL DEVICE QUALITY SYSTEMS Page 1

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1 1 TABLE OF CONTENTS Introduction Pg 1 Electromagnetic Compatibility Pg 2 IEC Pg 2 EMC in GMP Inspections Pg 3 Design Controls Pg 3 Device Labeling Content Pg 5 Purchasing Controls Pg 6 Inspection, Measuring & Test Equip Pg 6 Production/Process Controls Pg 7 Handling/Storage Pg 7 Device Master Record Pg 7 Complaint Files Pg 7 Servicing Pg 8 Corrective/Preventive Action Pg 9 Recalls/Upgrades Pg 11 Inspection Reports/Observations Pg 12 Appendix A Pg 13 Appendix B Pg 14 Appendix C Pg 15 Appendix D Pg 16 Appendix E Pg 17 INTRODUCTION This guide was prepared by the FDA, Office of Regulatory Affairs, and the Center for Devices and Radiological Health (CDRH), Office of Compliance. This guide provides FDA investigators with information regarding electromagnetic compatibility (EMC) and how it is likely to be addressed in a medical device firm's Quality System/Good Manufacturing Practices (QS/GMP) (21 CFR Part 820). Terms throughout this document that are in bold typeface are defined in Appendix A. 1 von :10

2 THIS DOCUMENT APPLIES ONLY TO ELECTRICALLY POWERED (MAINS OR BATTERY) DEVICES. It includes information on the following: 1. electromagnetic disturbances (EMD), including radiated and conducted emissions, as well as electrostatic discharge (ESD); 2. electromagnetic interference (EMI), susceptibility and immunity; 3. international and voluntary EMCstandards, such as IEC ; (these are not FDA performance standards or mandatory requirements.) 4. areas of the new Quality System regulations where EMC is likely to be addressed; 5. how the regulations apply to EMCissues in continuing production of existing devices, design and production of new or modified devices, and upgrades and recalls of marketed devices; and 6. expectations and limitations of the GMP inspection process regarding EMC. The Center for Devices and Radiological Health (CDRH) is encouraging firms, many of whom have never considered some of these issues, to begin the process of addressing EMC. The goal is to improve the industry norm, not to penalize industry efforts to design EMC into their devices. There are a number of confounding factors in achieving EMC. Manufacturers can design EMCinto their electrical devices for most expected use environments, depending on design options for proper functioning or electrical safety, intensity or variableness of environments, the 2 statistical confidence of measurements, and costs. However, EMC cannot be achieved in every environment. Additional appropriate labeling may be necessary in some situations. Comments on this guide are welcome and may be sent to: Joanne Barron, FDA/CDRH (HFZ-342), 2098 Gaither Road, Rockville, MD ( 2 von :10

3 address: and/or DEIO, Medical Device Group (HFC-130), 5600 Fishers Lane, Rockville, MD (internal address: References: Design Control Guidance for Medical Device Manufacturers, FDA/CDRH, March 11, 1997; Do It By Design, An Introduction to Human Factors in Medical Devices, FDA/CDRH, December 1996; Design Control Inspectional Strategy Report, FDA, May 1997; and, Medical Device Quality Systems Manual: A Small Entity Compliance Guide, FDA/CDRH, December ELECTROMAGNETIC COMPATIBILITY Electrical and electronic products are capable of being interfered with and interfering with other products through transfer of any of several forms of energy. These forms of electromagnetic energy include: radiated energy - through air or media such as walls, conducted energy - through power and signal lines and cables, or electrostatic discharges (ESD) - through air or direct contact. FDA investigators may be familiar with the terms radiofrequency interference (RFI) and ESD with regard to GMP process controls. However, current standards use the term electromagnetic disturbance (EMD) for the electromagnetic environment to distinguish it from either of two possible responses of the product, electromagnetic interference (EMI) or electromagnetic compatibility (EMC). Electrical and electronic products can both produce and receive such energy (intentionally or unintentionally), referred to as "transmitters" and "receivers." Receivers are susceptible to degradation of performance - EMI - unless they are designed and constructed to be immune to the energies -EMC. The goal of EMCis that expected energy in the environment - EMD - will not degrade the 3 von :10

4 performance of a product and that the product will not interfere with another product. This means medical devices should: 1. Account for the expected electromagnetic environment in the design and labeling of the device (from other medical devices, consumer electronic products, commercial and private radio transmissions, power line disturbances, and (ESD), 2. Accomplish its intended purpose without degradation of performance in the expected environments, and 3. Not interfere with other devices expected to be used in the same environment or provide sufficient labeling for safe use. REMINDER: These can be confusing terms and acronyms. EMC - compatibility in the same environment - is our goal. EMI - interference - is what we want to prevent. EMD - disturbance - is the electromagnetic environment. IEC AND OTHER EMC STANDARDS Over the past 20 years, several standards applicable to medical devices were developed with EMC requirements, primarily standards for military products (MIL-STD), the Association for the Advancement of Medical Instrumentation (AAMI) pacemaker standard, and a 1979 medical device EMC standard (MDS ). The latter two standards were written under contracts from FDA but were not adopted as mandatory; they are considered voluntary guidance. Recently, the international standards development process, in which FDA has participated, has developed significant and appropriate standards. 3 They are not ideal, but when used, they certainly 4 von :10

5 increase product safety. Appendix B lists examples of available standards. CDRH encourages manufacturers of electromedical equipment to use the IEC standard, a widely recognized standard issued by the International Electrotechnical Commission, Geneva, Switzerland. [NOTE: IEC recently renumbered the standards, adding to all previous numbers, so investigators may know it as IEC ] It is a collateral standard to IEC , which is a horizontal (product family) standard intended to apply across many medical disciplines. Other standards such as MIL-STDs or some industry standards may be appropriate as well. It is the manufacturer's responsibility to determine the most appropriate specifications and requirements for their devices. If conformance claims have been made in a PMA or the labeling, however, the GMP documents should contain documented evidence consistent with and supporting those claims. The IEC series currently includes a general safety standard, four collateral standards (systems, EMC, diagnostic x-ray protection, and programmable electrical medical systems), and over 40 particular, or product specific standards that adapt the general and collateral standards. Related international standards contain details of the IEC requirements and test methods (e.g., International Special Committee on Radio Interference (CISPR) standards CISPR 11 and CISPR 16, and IEC x which supersedes the obsolete IEC 801-x series). FDA investigators may be aware of IEC 801-2, since many firms have used it to determine requirements for controlling ESD during manufacturing. These standards are subject to frequent revisions and many documents have to be reviewed simultaneously to determine the current requirements. Hence, manufacturers of the same device, claiming to meet the same standard, may have differing specifications. Firms may claim partial or complete conformance to IEC or may have alternate test methods or parameters. Partial conformance may be adequate if the firm substantiates and/or justifies the deviations. The IEC standard provides various limits on emissions and immunity. While these 5 von :10

6 limits are clear, the pass/fail criteria are not. Therefore, CDRH encourages manufacturers to clearly specify all deviations from the standard, their specific pass/fail criteria, and justifications as part of their GMP documentation. (NOTE that IEC is not applicable to in vitro diagnostic devices or sterilizers but may be used.) EMC IN GMP INSPECTIONS FDA investigators should assess a firm's EMC activities while conducting an overall inspection of their Quality System/Good Manufacturing Practices (QS/GMP). This guidance is not intended for separate inspections. Manufacturers of electrical products may have included EMC requirements in parts of the QS/GMP process when: 1. FDA required safety and effectiveness data on emissions and immunity in a premarket approval application (PMA), 2. FDA requested information in the premarket notification (510(k)) submissions due to a history of interference issues or recent significant EMI concerns, or 3. a firm has voluntarily, or based on complaints, begun to address some EMC issues. DESIGN CONTROLS EMC generally needs to be designed into the product. Therefore, the following questions regarding EMC are included in the Design Control Inspectional Strategy (DCIS), dated March 1997: "820.30(c) Design input For an electrically powered device, where electromagnetic compatibility (EMC) should have been considered in the design, determine the following: 1. How has EMC been addressed with regard to the device use environment? For 6 von :10

7 4 example, the interface with other medical devices or the interference from other consumer products? 1. If complaint or failure data for similar devices distributed by the manufacturer indicated EMCproblems, did the manufacturer use this information in establishing the design requirements for the new device? 2. Identify any relevant EMC standard(s) used as a part of the design input process." AT THIS TIME FDA DOES NOT REQUIRE CONFORMANCE TO ANY EMC STANDARDS. HOWEVER EMC SHOULD BE ADDRESSED DURING THE DESIGN OF NEW DEVICES OR REDESIGN OF EXISTING DEVICES, ESPECIALLY IF EMC INFORMATION HAS BEEN REQUIRED FOR PREMARKET CLEARANCE. In the DCIS, Investigators are asked to determine during an inspection of design control activities what, if anything, manufacturers are doing to design electrical and electronic devices for EMC. The most significant phases where EMC should be addressed are design input and design verification. If reports of EMI implicate either a design problem or any other GMP problem, the investigator may find the questions in Appendix E helpful in guiding the inspection. Appendix E is to be used only for help in understanding the application of the DCIS to EMC issues, not for reporting findings of the inspection. 21 CFR (c) Design Input It is important for a manufacturer of electrical devices to determine how EMC will be addressed with regard to the device use environment. Possible EMD - from and to other medical devices or from consumer electronic products, commercial and private radio transmissions, power line disturbances, and ESD - needs to be evaluated. Example: A ventilator is likely to be used in conjunction with other devices such as patient monitors. The ventilator performance may be affected by EMD from other devices and/or 7 von :10

8 non-device sources such as cellular phones or two-way radios. The ventilator may emit EMD which interferes with other devices used in the same area. A manufacturer may have complaint, failure, or service data or have experience with device performance problems caused by EMI. Such information should be used in establishing the design specifications of the redesigned device. If a manually operated device is being redesigned to add electronic controls, the manufacturer may not have any past experience with EMI problems with that device. Research will be needed to identify sources of EMD in the use environment. The same is true for a totally new device. MDR reports from other manufacturers' similar devices may be helpful in identifying EMI problems. The firm also should have criteria for deciding when and how EMC will be addressed in labeling in addition to the product design. 21 CFR (d) Design Output The design system should identify and define the design output in regard to EMC. Components such as cables and housing may have shielding to protect the device from EMD. The output must be defined in terms of measurable performance of the device so that appropriate testing and verification can be performed. Thus EMC may be addressed through a combination of specifications for components and performance requirements for sub-assemblies and the finished device. 21 CFR (f) Design Verification Verification methods and activities are required to confirm that input requirements for EMChave been fulfilled by design output. Verification will often be a physical test of the product, a subassembly or component of the product to determine if the specified EMC criteria or specification (design input) was met by the final design (design output). If design input includes specifications based on requirements in IEC or other EMC standards, the firm should determine who will test the design output 8 von :10

9 5 for conformance to these requirements and who will certify conformance to the standard. Because expensive equipment and facilities are needed for other than ESD testing, independent laboratories and larger manufacturing firms are more likely to have the capability of testing products for conformance with EMC standards than are smaller manufacturers. Any certification or declaration of conformance to IEC or other EMC standard should be supported by the following types of documentation, including appropriate justifications: 1. applicable collateral or particular standards that were used. 2. any EMC requirements that are not applicable to the device. 3. test levels, pass/fail criteria, variances from test criteria, and pass/fail results. 4. any differences between the tested device and the device to be marketed. 5. name and address of the certification body and by whom and how it is accredited. 6. other EMC standards and guidelines applicable to the particular medical device. (See Appendix B.) 21 CFR (g) Design Validation Validation is use of the final device to determine if it operates as intended in the expected use environment. Example: A laboratory test exposing the device to MHz fields is verification, while trial use of the device in a clinic where cellular phones are used in adjacent rooms is validation. Validation activities for EMC may include clinical evaluations or use simulations. They should be conducted on production devices or the manufacturer should demonstrate how the tested devices are equivalent to production devices. Some EMI may be considered clinically acceptable if the hazard is reduced as much as possible through design and adequate precautions, 9 von :10

10 warnings, and instructions for safe use are provided. Both hardware and software can affect EMI responses so validation should address EMI of an integrated system, especially if verification of hardware and software were done separately. Also be aware that since cellular telephone systems, other transmitters, and electrical supplies are different in foreign countries, devices intended for export may undergo unusual validation methods. 21 CFR (i) Design Changes For devices already being produced and marketed, EMC may be addressed for the first time during design changes. A device manufacturer should determine the criteria for when and how EMC specifications will be added to the design process. DEVICE LABELING CONTENT Labeling in place of design controls usually is not adequate to prevent adverse events. It should supplement EMC design and testing to address any precautions that need to be taken by users despite the design considerations. Users can enhance safety and effectiveness of devices susceptible to EMI if they are provided clear guidance for avoiding, identifying and resolving EMI problems, information on conformance to existing standards including how testing was done, and possibly recommended separation distances from other devices or EMD sources. Adequate labeling is particularly important if the device is often used in high field strength environments and cannot be made to function as intended in these environments. If a device cannot meet applicable test requirements, if certain tests have been omitted, or there are competing safety issues, device labeling may be used to warn the user of the potential of EMI from exposure to outside EMD sources and/or of emissions from the subject device that may affect other equipment. If a firm makes a declaration of conformance to IEC , that standard specifies that the labeling include: 1. guidelines for avoiding or identifying adverse electromagnetic effects; 10 von :10

11 6 2. restrictions of use of the device; and 3. justification for any immunity levels that are lower than the standard's general immunitytest levels, as well as any actions that need to be taken by a user or installer as a result. In addition, the PMA or 510(k) may have required specific EMC labeling. Investigators should collect copies of any questionable labeling for review by CDRH. PURCHASING CONTROLS 21 CFR (a) Evaluation of suppliers, contractors, and consultants All purchased or otherwise received products and services must conform to specified requirements (specifications). Since design verification for EMC will often be done by type-testing at a contract laboratory, purchasing controls apply to that contractual arrangement. The device manufacturer may require that the product meet certain safety requirements, such as those specified in IEC , or some other standard. When adherence to such a standard is specified, the FDA investigator should identify which standard and what sections of the standard the product is intended to be in conformity with, and then review the finished device manufacturer's product specifications as provided to the vendor, as well as the documentation (if any) provided by the vendor to the device manufacturer for verification of conformity. Manufacturers of finished devices should clearly convey to a vendor the specified requirements for the product to be procured from the vendor, including the quality, functional, and safety characteristics for the product. When the product supplied by the vendor is itself an electrical component (e.g., shielded cables, filters, circuit boards), and/or will be used in or with an 11 von :10

12 electronic medical device (i.e., an accessory), the finished device manufacturer should provide the vendor with the EMC requirements for that product. This includes: 1. product electrical specifications, such as the type of cable or electrical parameters of a component or filler material, 2. any testing requirements, such as use of an anechoic chamber or GTEM cell or specific EMD frequency ranges or distance of the signal from the device, 3. shipping and storage requirements (if necessary), 4. testing documentation (if performed), and 5. documentation to be supplied to the medical device manufacturer (e.g., certificates of analysis, certificates of conformance, raw test results, etc.) 21 CFR (b) Purchasing Data Manufacturers are encouraged to have a written agreement with the vendor for advanced notification of any changes to vendor manufacturing, product design, or testing prior to implementation. If the vendor is unwilling to enter into such agreement, the finished device manufacturer should demonstrate that an effort was made, and demonstrate how their receiving inspection department is capable of identifying product that is changed in some manner affecting EMC prior to acceptance and use. INSPECTION, MEASURING & TEST EQUIPMENT 21 CFR (a) Control of Inspection, Measuring, and Test Equipment For the finished medical device manufacturer who produces electronic devices, the role of inspection, measuring and test equipment, calibration, and calibration standards during the various phases of production is significant. Such equipment could range from a simple volt-ohm meter to a complex computer-controlled radiation detector. Therefore, it is very important that the manufacturer select, design (where appropriate), and operate this equipment in a manner which both prevents any damage to the medical device, and accurately detects adherence or non-adherence to electrical or EMC specifications 12 von :10

13 for the device. Routine inspection and calibration (where 7 appropriate) of inspection or test equipment (e.g., for correct operation and electromagnetic emissions) are essential. Equipment used to detect electromagnetic emissions should operate within the limits specified for accuracy and precision and should be appropriate for the frequencies, field strengths, angle of incidence, and distance from theemd source. The manufacturer should justify the inspection, calibration, and maintenance schedule for each piece of test equipment based on historical use, experience, vendor specifications, or a combination thereof. 21 CFR (b) Calibration For some equipment, conformity or calibration to standards may be demonstrated by a classification marking on the piece of equipment or accompanying documents from a testing laboratory (e.g., Underwriters Laboratories, Inc.). This, however, does not obviate the need for routine calibration checks, maintenance, and recalibration. PRODUCTION AND PROCESS CONTROLS 21 CFR (c) Environmental Control Since electronic components can be susceptible to damage from high levels of EMD,production and process controls should address EMI concerns. FDA investigators are generally aware of the need for ESD controls for printed circuit boards such as use of grounding devices (e.g., worker wrist straps) and use of appropriate plastic storage containers. In addition, the firm may need controls on such things as use of cellular phones and two-way radios in the manufacturing areas or very close (10-20 cm) to components and subassemblies, machinery qualifications for 13 von :10

14 radiated emissions and/or ESD generation, the installation and distance from susceptible components of new machinery that may be a source of EMD, re-arrangement of existing machinery, and the susceptibility of the manufacturing and test equipment to power surges and outages. HANDLING AND STORAGE 21 CFR and Handling and Storage Many electronic components (e.g. circuit boards) and subassemblies are very susceptible to EMD, particularly ESD. Verify the firm has documented and implemented procedures for minimizing damage similar to those needed for process controls, if appropriate to the device. DEVICE MASTER RECORD 21 CFR Device Master Record (DMR) Investigators should verify that any instructions or procedures for production, installation, maintenance, and servicing related to ESD or other sources of EMD are included, or referred to, in the DMR. If the PMA or 510(k) includes EMC claims or test results, the DMR should include EMC design specifications and drawings, EMC test results, and possibly labeling and packaging specifications. COMPLAINT FILES Electrical devices are subjected to many influences in the use environment, both expected and unexpected. Since radiated or conducted EMD is unseen and can be transient, EMI events are difficult to detect or duplicate. Sometimes the operation of a device recovers after an EMI event, sometimes the device must be reset by an operator, and sometimes the device is permanently damaged. Intermittent hardware malfunctions and software "bugs" can mimic EMI events and some intense EMD events can cause component failures. 21 CFR (a) Establish and Maintain Complaint Handling Procedures 14 von :10

15 The firm should process acquired information in a uniform and timely manner so that details are still fresh in the user's memory and all peripheral information can be synthesized to evaluate for: 1. additional events which may have contributed to the EMI (e.g., construction 8 at the facility during this time period or a power outage); additional diagnostic procedures that necessitated use of other devices which may have contributed to the EMI (e.g., a portable x-ray machine was being used at the other end of the room on another patient at the same time the event occurred); 2. additional equipment used in conjunction with the subject device (e.g., radiant heater used over a neonate's crib); 3. environmental conditions which may have contributed to the event (e.g., static charge was high because of dry climate that day, the adverse event occurred during a thunderstorm). 4. repeatability of the event and comparison to similar events at the same facility or other geographic areas (e.g., radio transmissions of delivery vehicles at the loading dock in a hospital caused ECG monitors to malfunction on that side of the building). 21 CFR (b) Determining Whether An Investigation Is Necessary Any complaint involving EMI should be evaluated and investigated by the firm, unless such investigation has already been performed for a similar complaint and another investigation is not necessary. Documentation should justify why another investigation is not necessary. The firm may need to determine if a complaint is EMI-related, aided by the following types of questions: 1. Based on the information at hand, is EMI a possible or probable cause for the malfunction? (See the possible keywords for 15 von :10

16 EMI in Appendix D.) 2. Could the erratic behavior or the intermittent malfunctioning of the device be related to a hardware problem, user error, deficiency in the manufacturing process, or a possible EMDsource? What is the basis for the conclusion? If the answers to the above questions do not indicate that EMI was a causative factor, then that information should be documented as the reason for not investigating EMI and the name of the individual responsible for the decision not to investigate for EMI aspects. 21 CFR (d) Determination of MDR Events Complaints should be evaluated by the firm for: 1. circumstances leading to the event (e.g., ESD occurred in the winter and humidity was not controlled in the hospital); 2. consequences or risk of the event to the patient or the caregiver (e.g., ESD from the side rails of the bed caused arcing to affect a ventilator) (Appendix C may be helpful in determining the risk of an EMI event.); and 3. criticality of the event if it should recur (e.g., infusion pump stopped pumping and alarmed due to a cellular telephone). The firm should determine if the complaint is a true positive (correctly attributed to EMI by the reporter), false positive (incorrectly attributed to EMI by the reporter), or false negative (not attributed to EMI by the reporter yet probably was EMI). Questioning should demonstrate correct categorization so that appropriate follow-up at the user and manufacturer facilities can occur and appropriate complaints will be submitted to FDA under the Medical Device Reporting regulation, 21 CFR, Parts 803 or 804. Any EMI-related MDR reportable event should be maintained in a separate portion of the complaint files or otherwise clearly identified. Records should follow the Quality System regulations. SERVICING 21 CFR (a)&(b) Analyzing Reports 16 von :10

17 and Establishing and Maintaining Procedures For Performing and Verifying That Servicing Meets Specified Requirements Manufacturers should thoroughly analyze service reports associated with EMI, and document corrective and preventive action in accordance with 21 CFR Failure trends by grouping failures by location, user application, repeat component failures, etc., can yield evidence or potential EMC problems CFR (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 CFR (d) Documentation of Service Reports Service reports for potential EMI problems should be documented by the firm in accordance with the Quality System regulations. CORRECTIVE AND PREVENTIVE ACTION 21 CFR (a) Corrective and Preventive Actions 1. Analyzing Quality Problem Information 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 17 von :10

18 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. 2. Investigating or Determining the Cause 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 18 von :10

19 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 10 not impossible to pinpoint because it is not possible to determine the exact circumstances of an incident after it has occurred. It might even be impossible to detect during an event if the source is unseen, intermittent, and/or mobile. Example: A monitored patient (and his nurse and doctor) may not be aware of the cellular telephone in the pocket of another patient's visitor. However, it is sometimes possible for a firm to establish the credibility of an incident by duplicating the problem in the normal use environment or in the laboratory. A firm should be aware that if it services or investigates a device outside its normal use environment, the device may experience a significantly different electromagnetic environment which may possibly mask an EMD source found during normal use. Example: Interference from some electrosurgical units (ESUs) disrupted the communication link between an anesthetic gas monitor and a central mass spectrometer, causing the monitor to fail to display the concentration of anesthetic gas in the operating room during surgery. When testing to find the failure mode, a firm might not think of simulating an ESU with these devices in a 19 von :10

20 laboratory. If a device type is known to be susceptible to EMD and a cause cannot be attributed to something other than EMD, the firm should conduct "ad-hoc" susceptibility testing in an environment simulating the actual use environment. If the firm determined that EMI is the cause of the device's nonconformance, the investigator should question whether any product lines using similar designs and subject to the same environment have been assessed or determined to be prone to EMI. Investigators should also review records maintained under the requirements of 21 CFR , to determine if data can further identify the problem to a manufacturing step, work station, or one or more employees. 3. Identifying a Solution or Preventive Action When EMI is confirmed, a firm will often choose to shield the device (e.g. different selection of shielded cable, cabinet shielding, etc.) and/or redesign the vulnerable circuit(s). Labeling containing warnings or precautions may be necessary to supplement the design changes. The specific EMD source that caused the device malfunction may not be the only source which will affect the device performance. The firm should also attempt to determine any other EMDsources that can be expected in the use environment which may have emerged since the design inception. Whatever action is proposed should consider the frequencies, power output, modulation characteristics, proximity, and shielding of the EMD sources that affect the device, as well as the user's ability to be aware of and control the proximity of EMD sources. Example: Cellular telephones are not always seen and proximity to equipment cannot always be controlled. 4. Verifying or Validating the Solution The device should be verified or validated with new shielding and/or new circuitry and/or other physical adaptation in place. If verification is performed, the firm should test the device in a laboratory to a generally recognized EMC standard or a reasonable and well-defined test protocol, 20 von :10

21 simulating conditions of use. Testing should be conducted on finished devices. If a device is to be offered sterile and reusable, the device should be tested after several cycles of sterilization as well. If the design change is not verified, the device performance must be validated in the actual environment or an accurate simulation of it. Labeling changes may be validated by querying different user populations as to whether they believe the labeling provides adequate warning. If verification or validation indicate that the solution does not solve the problem and prevent recurrence, this step will have to be performed again in its entirety once a new solution is identified. The firm should verify that the correction does not introduce any new EMI, electrical safety, or other problems Implementing and Recording Changes The changes which are implemented and recorded should be identical to the solution which was implemented for verification or validation. For example, no last-minute labeling changes should be made after validation. Any labeling changes should be validated and then fully implemented. The firm will have to decide whether the change should be implemented to existing units as well as new inventory. See the Recall and Upgrade section of this document for further guidance. 6. Disseminating Information A change to the device is most likely to be initiated by an engineering department. Other departments such as manufacturing, purchasing, production, quality assurance, regulatory affairs, etc. should be informed, since each will have its own responsibilities in effecting an EMC change. RECALLS AND UPGRADES 21 von :10

22 As manufacturers begin to test their devices to meet voluntary EMC standards, device modifications or labeling changes resulting from such testing generally will be considered upgrades. CDRH will not consider modifications of marketed devices to reduce EMI to be recalls unless there is a significant hazard or violation of the Federal Food, Drug, and Cosmetic Act (the Act). In certain cases, the Center or the firm might choose to issue a safety alert. As a result of a firm's analysis or an evaluation by CDRH, the firm may consider several options: issue warnings and guidance to the users, revise device labeling, modify the device, or conduct market withdrawals or recalls. If a labeling change or modification results in a new intended use, a new 510(k) may need to be submitted to CDRH. In the conduct of an upgrade or recall, the firm may choose to issue a letter to users, amend user guidance/operator instructions, and/or revise other labeling to provide warnings and recommendations for unusual or changing use environments. The Agency may determine that this additional user guidance adequately addresses the potential hazard and not require a recall. The determination whether a modification would constitute a recall or be considered an upgrade would be based on the hazard associated with the device's deficiency or whether the Act was violated. If CDRH or the manufacturer identifies that there exists a potential hazard in accordance with section 518 of the Act, then CDRH will classify it as a recall and require notification to purchasers following normal procedures as outlined in 21 CFR , the Investigations Operations Manual (IOM), Chapter 8, and the Regulatory Procedures Manual (RPM), Chapter 7. The Agency has authority under section 518 to require notification and recall if there is a reasonable probability that a device would cause serious, adverse health consequences or death. Appendix C may be helpful in determining the level of risk associated with EMI-related modifications to a device. The following are examples of various situations: 1. Upgrade: wheelchairs When CDRH testing determined that certain 22 von :10

23 powered wheelchairs and powered scooters were susceptible to EMD, manufacturers worked with CDRH to investigate the problems. CDRH scientists developed improved test methods. In addition, one wheelchair manufacturer worked in cooperation with CDRH to make appropriate shielding and circuitry modifications, resulting in greatly improved immunity. Although CDRH determined that there was not enough evidence to warrant a recall, CDRH notified manufacturers that future premarket submissions on powered wheelchairs and scooters should address EMC in labeling and testing. The modifications and revised labeling are considered upgrades. 2. Recall: Apnea monitors As a result of CDRH testing on one model 12 of apnea monitors, CDRH determined the devices were so susceptible to expected EMD to be sufficiently hazardous and in violation of the Act. The manufacturer agreed to recall and correct the products. 3. Safety Alert: Ventilators Although the device complied with IEC , the manufacturer determined in the laboratory that the units displayed functional irregularities, such as a flashing display, when exposed to high ESD or EMD fields, at levels above the IEC standard. Because normal operation would resume in a few seconds and there was little likelihood of patient injury, the firm issued a safety alert to purchasers recommending a proper EM environment. The firm concurrently developed improved software that provides further immunity to EMD. The software replacement was performed voluntarily by the manufacturer and at no cost to the customers. The enhanced software constituted an upgrade. Inspection Reports and Observations 23 von :10

24 Investigators may discuss any EMC issue with a firm. All concerns should be documented in the Establishment Inspection Report (EIR). The EIR should include information on the DMR, product testing, qualifying laboratories, complaint handling, failure investigations and design controls, as appropriate. Investigators must document design aspects of inspectional information using the Design Control Inspectional Strategy (DCIS) report from June 1, 1997 through May 31, The design control questions in Appendix E are to be used only for reference in understanding the scope of the DCIS questions as they apply to EMC issues. EMI issues should NOT be cited on the Form FDA 483, Inspectional Observations, unless they can be related to GMP deficiencies. Examples of non-design GMP deficiencies that may be cited on the FDA 483 are: 1. failure to conduct an investigation of an MDR - reportable EMI malfunction or injury; 2. failure to file an MDR for a reportable EMI event; 3. failure to maintain appropriate environmental controls for processing of electronic components known to be susceptible to ESD; or 4. failure to maintain proper incoming controls for electronic components. 13 APPENDIX A - DEFINITIONS (EMC)- the ability of a device to function a) properly in its intended energy environment and b) without introducing excessive electromagnetic energy that may interfere with other devices. ELECTROMAGNETIC DISTURBANCE (EMD)- any electromagnetic phenomenon which may degrade the performance of equipment (e.g., 24 von :10

25 devices). Examples include electromagnetic fields (radiated emissions), electrostatic discharges, and conducted emissions. ELECTROMAGNETIC INTERFERENCE (EMI) - degradation of the performance of a piece of equipment, transmission channel, or system (e.g., medical devices) caused by an electromagnetic disturbance. ELECTROSTATIC DISCHARGE - the rapid transfer of electrostatic charge between bodies of different electrostatic potential, either in proximity in air (air discharge) or through direct contact (contact discharge). EMC - See Electromagnetic Compatibility. EMD - See Electromagnetic Disturbance. EMI - See Electromagnetic Interference. EMISSIONS - CONDUCTED EMISSIONS - electromagnetic energy introduced into a product through a conductor by means of resistance, inductance or capacitance. Conductors include AC power cords, metallic enclosures of a subsystem, or cables interconnecting subsystems or the patient to the product. Conducted emissions include power line anomalies, harmonics, surges, EFTs (electrical fast transients), and radiofrequencies, especially 150kHz to 80 MHz. RADIATED EMISSIONS - electromagnetic energy emanating from a device and propagating through space or a medium (which can affect the distance and direction of propagation). ESD - See Electrostatic Discharge. IMMUNITY - the ability of an electrical or electronic product to operate as intended without performance degradation in the presence of an electromagnetic disturbance. RECALL - a firm's removal or correction of a marketed product that (1) the FDA considers to be inviolation of the laws it administers and against which the FDA would initiate legal action or (2) where the FDA finds that there is a reasonable probability that the device would cause 25 von :10

26 serious, adverse health consequences or death. This is contrasted with a device upgrade, defined below. RADIOFREQUENCY - a frequency in the portion of the electromagnetic spectrum that is between the audio and the infrared portions. Commonly used radio frequencies range from 9 khz to 100 GHz. RFI - Radio Frequency Interference; one type of EMD, resulting from radiated emissions from broadcast antennas or electronic emitters. SUSCEPTIBILITY - the potential for equipment (e.g. devices) to respond to an electromagnetic disturbance. UPGRADE - an action taken voluntarily by a device manufacturer to improve or enhance the performance or safety of a device when there is no violation of the FD&C Act and it would not cause serious, adverse health consequences or death. An upgraded device would still perform as it was originally designed and labeled to do, in accordance with its premarket clearance specifications. The design change may be brought about due to user recommendations, improved technology, compliance with government or industry standards, or may be a natural evolutionary development. A product upgrade may or may not result in the return of the device to a facility to institute the retrofit/upgrade. VULNERABILITY - See susceptibility. 14 APPENDIX B - EXAMPLES OF EMC STANDARDS AAMI (FDA/HFK-76-38), Pacemaker Standard (draft), This standard, which was never finalized, included some EMC requirements. It is currently being revised. CISPR 11, Limits and Methods of Measurement 26 von :10

27 of Electromagnetic Disturbance Characteristics of Industrial, Scientific, and Medical (ISM) Radiofrequency Equipment, CISPR 14, Limits and Methods of Measurement of Radio Interference Characteristics of Household Electrical Appliances, Portable Tools and Similar Electrical Apparatus, CISPR 16, CISPR Specification for Radio Interference Measuring Apparatus and Measurement Methods, CISPR 22, Limits and Methods of Measurement of Electromagnetic Disturbance Characteristics of Information Technology Equipment (ITE), IEC , Medical Electrical Equipment, Part 1: General Requirements for Safety, 2. Collateral Standard: Electromagnetic Compatibility -Requirements and Tests, This standard sets limits based on the IEC 801 and 1000 series standards and the CISPR 11, 14, 16 and 22 standards. IEC 801-x, Electromagnetic Compatibility for Industrial-Process Measurement and Control Equipment. This series of standards has been superseded by the IEC x series, which is referenced in more recent product family and generic EMC standards. IEC 801-1, General Introduction, IEC 801-2, Electrostatic Discharge Requirements, IEC 801-3, Radiated Electromagnetic Field Requirements, IEC 801-4, Electrical Fast Transient/Burst Requirements, IEC 60878, Graphical symbols for electrical equipment in medical practice, IEC x, Electromagnetic Compatibility (EMC) Part 4: Testing and Measurement Techniques IEC , Overview of Immunity Tests, IEC , Electrostatic Discharge Immunity Test, IEC , Radiated, RF, EMF Electromagnetic Fields Immunity Test, von :10

28 IEC , Electrical Fast Transient/Burst Immunity Test, IEC , Surge Immunity Test, IEC , Immunity to Conducted Disturbances, Induced by RF, IEC , Harmonics and Interharmonics Measurements and Instrumentation for Power Supply Systems, IEC , Power Frequency Magnetic Field Immunity Test, IEC , Pulse Magnetic Field Immunity Test, IEC , Damped Oscillatory Magnetic Field Immunity Test, IEC , Voltage Dips, Short Interruptions, and Voltage Variations Immunity Test, IEC , Oscillatory Waves Immunity Test, IEC , EMC Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use (draft), MIL-STD-461D, Requirements for the Controls of Electromagnetic Interference Emissions and Susceptibility, January 11, MIL-STD-462D, Measurements of Electromagnetic Interference Characteristics, January 11, MIL-STD-463A, Definitions and System of Units, Electromagnetic Interference and Electromagnetic Compatibility Technology, June 1, MDS , Electromagnetic Compatibility Standard for Medical Devices, October 1, This standard was developed under contract from FDA by McDonnell Douglas, but was not adopted as mandatory; it is considered a voluntary guideline. UL , Medical Electrical Equipment, December This standard includes the text of the IEC standard with U.S. national deviations for such things as wire coding. A UL mark for conformance with this standard, however, does NOT cover EMC unless the certification paper specifically so states. 28 von :10

29 15 APPENDIX C - PRIORITIZATION OF RISK Device Function Life supporting or sustaining (high) Patient monitor with alarm (possibly high) Used for drug delivery (possibly high) Automated diagnosis function (possibly high) Interconnected with other critical devices (medium to low) Failure or Malfunction Consequences Lead to patient death (high) Serious injury (possibly high) Minor injury (medium) Possible EMI, but no direct patient/user injury (medium) EMI Events History EMI-related incidents associated with death or serious injury (high) Numbers or types of reports of concern (high to medium) EMI-related incident reports, other (medium) Intended Use Environment Intended use in operating rooms, intensive or critical care units, or other critical care area (high) Many sources of EMD: radio transmitters, cellular telephones, high power transmission lines (possibly high) Intended or typically used in transport vehicles (possibly high) Few sources or low power EMD sources (medium to low) EM Emissions Device or accessory intentionally emits electromagnetic energy or radiation (high) Device has pumps, motors, large power supplies or digital components that may emit electromagnetic energy (high to medium) Device is AC (alternating electrical current) or 29 von :10