An FDA Perspective on Medical Device EMC and Wireless

Transcription

1 Center for Devices and Radiological Health An FDA Perspective on Medical Device EMC and Wireless Jeffrey L. Silberberg US Food and Drug Administration (FDA) Center for Devices and Radiological Health (CDRH)

2 Jeffrey L. Silberberg, MSEE Senior Electronics Engineer FDA/CDRH Office of Science and Engineering Laboratories Secretary, IEC SC62A MT23 May 8, 2015 Wireless Electronics and Electrical Medical Devices 2

3 Summary Medical device EMI continues to be reported Most reports involve active implanted devices Defibrillators Pacemakers Neurostimulators Infusion pumps RF wireless technology in healthcare is proliferating May 8, 2015 Wireless Electronics and Electrical Medical Devices 3

4 Summary (cont d) RF Wireless Technology FDA guidances Coexistence FDA participates in many standards activities FDA currently recognizes (among many others) IEC Ed. 3 IEC Ed. 4 Many X and X standards May 8, 2015 Wireless Electronics and Electrical Medical Devices 4

5 Summary (cont d) FDA coordinates with FCC on EMC and wireless issues Completeness/quality of EMC information in regulatory submissions varies It saves time and money to get it right the first time! May 8, 2015 Wireless Electronics and Electrical Medical Devices 5

6 Topics Introduction Medical device EMI reports FDA research FDA standards activities FDA recognition of IEC RF Wireless Technology in Medical Devices Regulatory issues Conclusions May 8, 2015 Wireless Electronics and Electrical Medical Devices 6

7 Introduction U.S. Food and Drug Administration (FDA) Center for Devices and Radiological Health (CDRH) We assure that patients and providers have timely and continued access to safe, effective, and high-quality medical devices safe radiation-emitting products. medical occupational consumer products May 8, 2015 Wireless Electronics and Electrical Medical Devices 7

8 CDRH Coordination with FCC New wireless technology that could affect medical devices Rules changes that could affect medical devices New medical applications of wireless technology More on this later May 8, 2015 Wireless Electronics and Electrical Medical Devices 8

9 Office of Science and Engineering Laboratories Assesses state-of-the-art of device technology Performs leading-edge research Develops novel test methods and performs testing Participates in the development of consensus standards Consults with other offices in CDRH Reviews of regulatory submissions Enforcement actions Problem identification and resolution May 8, 2015 Wireless Electronics and Electrical Medical Devices 9

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13 Experiences We continue to receive reports of medical device electromagnetic interference (EMI) Most reports involve implanted ICDs, pacemakers, neurostimulators, and infusion pumps Proliferation of RF wireless technology In medical devices In hospitals WLAN and telemetry RFID EMC information in regulatory submissions is often incomplete and has errors May 8, 2015 Wireless Electronics and Electrical Medical Devices 13

14 Sources of EMI Information Mandatory reports Voluntary reports Compliance (enforcement) actions Professional contacts Device and system professionals EMC engineers and consultants Hospital engineers Trade and professional organizations Consensus standards groups Published literature May 8, 2015 Wireless Electronics and Electrical Medical Devices 14

15 Mandatory reporting requirements Medical Device Manufacturers Medical-device-related Deaths Serious injuries Malfunctions that caused or could have caused the above To the FDA May 8, 2015 Wireless Electronics and Electrical Medical Devices 15

16 Mandatory reporting requirements User facilities Medical-device-related deaths to both the FDA and the manufacturers Medical-device-related serious injuries only to the manufacturer May 8, 2015 Wireless Electronics and Electrical Medical Devices 16

17 Voluntary reports MedWatch Reporters can include Healthcare professionals Patients The general public MedSun Hospitals May 8, 2015 Wireless Electronics and Electrical Medical Devices 17

18 MAUDE Database Manufacturer and User Facility Device Experience Database Includes manufacturer, user facility, and voluntary reports Searchable at AUDE/search.CFM In 2013 there were more than 630,000 individual reports entered into MAUDE May 8, 2015 Wireless Electronics and Electrical Medical Devices 18

19 MAUDE Search Screen May 8, 2015 Wireless Electronics and Electrical Medical Devices 19

20 Maude Simple Search Screen May 8, 2015 Wireless Electronics and Electrical Medical Devices 20

21 Recent MAUDE data Slide courtesy MDR Analyst Karen Nast May 8, 2015 Wireless Electronics and Electrical Medical Devices 21

22 A quick search of 2014 reports (Simple) text search on 12/18/2014 for electromagnetic interference Over 500 reports found for 2014 Almost all were for implanted devices, primarily Cardioverter defibrillators (ICDs) Pacemakers Neurostimulators Infusion pumps Some implants had EMI detection Some EMI detections were due to lead wire problems May 8, 2015 Wireless Electronics and Electrical Medical Devices 22

23 Pacemaker and ICD Sensing Characteristics Pacemakers and ICDs must be able to sense low-level signals to be able to perform their intended use 1V 100mV 10mV 1mV 100uV Reject Pacemaker Sensing Curve Sense ICD Sensing Curve Reject 10uV Slide courtesy Seth Seidman Frequency (Hz) May 8, 2015 Wireless Electronics and Electrical Medical Devices 23

24 A quick search of 2014 reports (cont d) In a more thorough EMI search, many additional related search terms would also be used that were not used for this quick (simple) search, e.g. Electromagnetic compatibility EMI EMC Interfer Incompatible Incompatibility May 8, 2015 Wireless Electronics and Electrical Medical Devices 24

25 A quick search of 2014 reports (cont d) Some of the reports found appeared to be confirmed or reproducible actual EMI problems Many mentions of EMI were NOT confirmed EMI problems. Examples: Implantable cardioverter defibrillator - A secure sense warning was observed during device interrogation. Electromagnetic interference was suspected. The device was reprogrammed. The patient condition was good. May 8, 2015 Wireless Electronics and Electrical Medical Devices 25

26 A quick search of 2014 reports (cont d) Example mentions of EMI that were NOT confirmed EMI problems (cont d) Implanted cardioverter defibrillator -A review of the device data was completed by an engineer and because the source of EMI cannot be confirmed, must consider the possibility that the device malfunction [sic]. Programmer - The electromagnetic interference tape was slightly lifted and was also replaced. May 8, 2015 Wireless Electronics and Electrical Medical Devices 26

27 Apparent EMI problem examples MDR Report Key , Rec. 02/13/2014 Event Description: It was reported the patient had electromagnetic interference due to use of their electric razor. The patient had felt their stimulation turn on and off when they used the electric razor. It was stated the report showed 48 activations and a previous time of 170 activations. It was noted the close proximity of the electric razor to the implantable neurostimulator was likely the cause of the high activation count. May 8, 2015 Wireless Electronics and Electrical Medical Devices 27

28 Apparent EMI problem examples (cont d) MDR Report Key (cont d) Event description (cont d): Additional information was received indicating that electromagnetic interference was conclusively identified as the cause of low impedance measurement as it was determined that patient has weekly electric stimulation therapy. May 8, 2015 Wireless Electronics and Electrical Medical Devices 28

29 Apparent EMI problem examples (cont d) MDR Report Key , Rec. 11/12/2014 Event Description: There was an electromagnetic interference issue that occurred approximately two days prior to the initial report. The patient went through a theft detector in a shop, received strong stimulation, and the lead at the cervical level displaced. Impedance testing and reprogramming were performed. The implantable pulse generator (IPG) had a power on reset, which was resolved through reprogramming. The patient experienced pain and less than 50% therapy relief at the lead location. There was no patient injury. May 8, 2015 Wireless Electronics and Electrical Medical Devices 29

30 EMI report examples (cont d) Ventilator MDR Report Key Rec Jan 31, 2013 Respiratory therapist was standing in front of a high-frequency oscillatory ventilator. She had noticed that there was a change in delta-p and mean airway pressure was fluctuating by 10. Behind the therapist were 7 staff members using [smart phones]. When [they were] asked to move away from the ventilator, the delta-p stopped fluctuating. Manufacturer response: known issue documented in operator s manual. May 8, 2015 Wireless Electronics and Electrical Medical Devices 30

31 EMI report examples (cont d) Ventilator (cont d) Manufacturer said that the root cause of the reported event was EMI from cell phone use by the end user. EMI causes erroneous pressure readings that are not due to fluctuations in the actual pressure but are the effect of EMI on the components of the measurement circuits. Mfr continued that as the reported event was caused by the device being exposed to higher than normal EMI, an investigation is not required. May 8, 2015 Wireless Electronics and Electrical Medical Devices 31

32 Adverse events reported to FDA Provide a qualitative snapshot of adverse events Vary in quality and usefulness Include both coding of problems as well as narrative text Can be coded with multiple problem codes Slide courtesy MDR Analyst Karen Nast May 8, 2015 Wireless Electronics and Electrical Medical Devices 32

33 FDA adverse event report caveats Under-reporting of events Insufficient or inadequate information Inability to establish causality Inability to establish rate of adverse events Lack of denominator data Trends in numbers should be interpreted cautiously One report can be important Adapted from a slide by MDR Analyst Karen Nast May 8, 2015 Wireless Electronics and Electrical Medical Devices 33

34 MedSun Medical Product Safety Network icalproductsafetynetwork/default.htm Participants Clinical sites Participation is voluntary Feedback Follow-up May 8, 2015 Wireless Electronics and Electrical Medical Devices 34

35 EMI information from EMC professionals Noise in the image or ECG trace (conducted EMI) Telemetry dropouts (radiated EMI) Artifacts in the Image Noise in the ECG Trace Telemetry Dropouts Slide courtesy EMC engineer Dara McLain May 8, 2015 Wireless Electronics and Electrical Medical Devices 35

36 Examples of published EMI reports Gimbel et. al., Electronic Article Surveillance Systems and Interactions With Implantable Cardiac Devices: Risk of Adverse Interactions in Public and Commercial Spaces Mayo Clin Proc. 2007;82: , A 71-year-old man with a biventricular ICD reported receiving 2 ICD shocks while shopping in the automotive center of a large commercial retail store. There was an electronic article surveillance (EAS) pedestal near the checkout counter. May 8, 2015 Wireless Electronics and Electrical Medical Devices 36

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38 Example of EMI identification in published research Remko van der Togt et al., Electromagnetic Interference From Radio Frequency Identification Inducing Potentially Hazardous Incidents in Critical Care Medical Equipment, Journal of the American Medical Association, June 25, 2008, Vol. 299, No. 24, pp May 8, 2015 Wireless Electronics and Electrical Medical Devices 38

39 Example regulatory investigation Ambulatory insulin infusion pump exhibited lockup in use Manufacturer was able to mitigate problems by increasing ESD immunity to 30 kv May 8, 2015 Wireless Electronics and Electrical Medical Devices 39

40 An EMC recall case study: EMC conformity gone wrong Date Recall Initiated: March 17, 2008 Date Posted: July 23, 2008 Recall Number: Z Product: Model X extracorporeal blood circulation system Reason for Recall: Stops pumping: Interruption of Model X support may occur when using a Model Y Electrocautery Unit See Appendix for more information May 8, 2015 Wireless Electronics and Electrical Medical Devices 40

41 FDA/CDRH/OSEL EMC research Immunity testing, immunity test method development Susceptibility of patient cables of automatic external defibrillators (AEDs) below 80 MHz Comparison of results of conducted and radiated immunity testing Pacemakers and ICDs with cell phones Powered wheelchairs Ventilators May 8, 2015 Wireless Electronics and Electrical Medical Devices 41

42 OSEL EMC and wireless research Pacemakers, ICDs, and nerve stimulators with security systems Wireless technology / wireless coexistence Working with University of Oklahoma at Tulsa C63.27 Round robin RFID (readers) and medical devices May 8, 2015 Wireless Electronics and Electrical Medical Devices 42

43 FDA/CDRH/OSEL EMC research publications Seidman S. et al.: In vitro tests reveal sample radiofrequency identification readers inducing clinically significant electromagnetic interference to implantable pacemakers and implantable cardioverter defibrillators, Heart Rhythm, vol. 7, no. 1, pp , 2010 May 8, 2015 Wireless Electronics and Electrical Medical Devices 43

44 FDA/CDRH/OSEL EMC research publications (cont d) Seidman, Seth J., and Guag, Joshua W.: Ad hoc electromagnetic compatibility testing of nonimplantable medical devices and radio frequency identification, BioMedical Engineering OnLine, 11 July, 2013 Seidman, Seth J. et al.: Design of Unique Simulators to Evaluate Medical Device Susceptibility to Radio Frequency Identification Exposure, 2014 IEEE Electromagnetic Compatibility Magazine, Vol. 3, Quarter 1 May 8, 2015 Wireless Electronics and Electrical Medical Devices 44

45 A few of the many CDRH standards activities 2010 data 240 representatives 30 standards development organizations 500 standards activities AAMI AIM REG HCI ASC C63 ASTM IEC ISO RESNA May 8, 2015 Wireless Electronics and Electrical Medical Devices 45

46 CDRH EMC and wireless activities AAMI Wireless coexistence TIR working group FDA co-chair Document development in process Working group EMC test protocols for cardiac rhythm management FDA co-chair Working on EMC section of a standard for cochlear implants May 8, 2015 Wireless Electronics and Electrical Medical Devices 46

47 CDRH EMC activities (cont d) RFID Working with Association for Automatic Identification and Mobility (AIM Global) RFID Experts Group (REG) on protocol for testing immunity of medical devices to RFID systems Protocol (test method) completed Circulated to the REG for comment 4 May 2015 Comments due 22 May 2015 May 8, 2015 Wireless Electronics and Electrical Medical Devices 47

48 CDRH EMC activities (cont d) C63 standards C63.12, limit and test level setting C63.16, ESD C63.27, wireless coexistence IEC standards IEC TR , Medical electrical equipment Part 4-2: Guidance and interpretation Electromagnetic immunity; performance of medical electrical equipment and medical electrical systems May 8, 2015 Wireless Electronics and Electrical Medical Devices 48

49 CDRH EMC activities (cont d)- IEC IEC TR Scope: The IMMUNITY of medical electrical equipment and medical electrical systems Immunity test levels -1-2: reasonably foreseeable maximum -4-2: typical, the same for home and hospital Scheduled to be circulated for comment 8 May 2015 IEC Ed 5 May 8, 2015 Wireless Electronics and Electrical Medical Devices 49

50 Standards recognition Declaration of conformity to consensus standards recognized by FDA can be used in regulatory submissions Recognition and Use of Consensus Standards; Final Guidance for Industry and FDA Staff, issued 20 June ulationandguidance/guidancedocuments/ucm htm May 8, 2015 Wireless Electronics and Electrical Medical Devices 50

51 Search for recognized standards s/cfstandards/search.cfm Enter Standard Designation Number Click Search May 8, 2015 Wireless Electronics and Electrical Medical Devices 51

52 May 8, 2015 Wireless Electronics and Electrical Medical Devices 52

53 Standards recognition (cont d) Clicking on the title opens the supplementary information page for that recognition Date of Standard Address of Standards Organization CDRH Office and Division Associated with Recognized Standard Devices Affected Processes Affected: 510(k), PMA, PDP, HDE, GMP, Design Controls May 8, 2015 Wireless Electronics and Electrical Medical Devices 53

54 Standards recognition (cont d) Supplementary information page (cont d) Type of Standard Extent of Recognition Portion of standard recognized or entire standard Any transition dates from older version(s) Related CFR Citations and Product Codes Relevant Guidance FDA Technical Contacts May 8, 2015 Wireless Electronics and Electrical Medical Devices 54

55 Recognition of IEC Ed. 2 and Ed. 2.1 no longer recognized Ed. 3 will be recognized until April 1, 2017 (Subject to change) Ed. 4 recognized as of June 2014 Extent of Recognition Complete standard with the following exceptions: In Subclause 8.9, Table 8 on Page 39: The citation of Note b) under Conducted disturbances induced by RF fields (4 th Row) is not recognized. May 8, 2015 Wireless Electronics and Electrical Medical Devices 55

56 Recognition of IEC (cont d) Ed. 4 Extent of Recognition (cont d) Exceptions (cont d) Please note the following corresponding titles, subtitles or provisions: Subclause 8.9: IMMUNITY TEST LEVELS Table 8: Signal input/output parts PORT Note b): SIP/SOPS whose maximum cable length is less than 3 m in length are excluded 4 th Row: Conducted disturbances induced by RF fields May 8, 2015 Wireless Electronics and Electrical Medical Devices 56

57 Recognition of X and X standards Many are recognized Examples IEC :2012, Medical electrical equipment - Part 2-10: Particular requirements for the basic safety and essential performance of nerve and muscle stimulators ISO :2011, Medical electrical equipment - Part 2-12: Particular requirements for the safety of lung ventilators - Critical care ventilators May 8, 2015 Wireless Electronics and Electrical Medical Devices 57

58 May 8, 2015 Wireless Electronics and Electrical Medical Devices 58

59 RF Wireless Guidance Accessible at andguidance/guidancedocuments/ucm htm Motivation Increasing use of RF wireless in healthcare Increasing congestion (e.g., in ISM bands) Medical devices can be both source and recipient of disturbances Need for awareness of potential pitfalls By FDA reviewers By manufacturers May 8, 2015 Wireless Electronics and Electrical Medical Devices 59

60 May 8, 2015 Wireless Electronics and Electrical Medical Devices 60

61 RF Wireless Guidance (cont d) Methods Risk-based approach References to FDA Quality System Regulation May 8, 2015 Wireless Electronics and Electrical Medical Devices 61

62 RF Wireless Guidance (cont d) Considerations for design, testing, and use of wireless medical devices Selection and performance of wireless technology Wireless quality of service (QoS) Wireless coexistence Security of wireless signals and data EMC of the wireless technology Information for proper setup and operation Considerations for maintenance May 8, 2015 Wireless Electronics and Electrical Medical Devices 62

63 RF Wireless Guidance (cont d) Recommendations for Premarket Submissions for Devices that Incorporate RF Wireless Technology Description of device Risk-based approach to verification and validation Test data summaries Labeling related to wireless medical devices May 8, 2015 Wireless Electronics and Electrical Medical Devices 63

64 RF Wireless Guidance (cont d) EMC Because IEC :2007 exempts RF receivers from immunity testing in the exclusion band, the medical device s wireless communication(s) should be actively transmitting during EMC immunity testing. May 8, 2015 Wireless Electronics and Electrical Medical Devices 64

65 Wireless coexistence FDA reviewers have been asking manufacturers for wireless coexistence testing since at least 2004 No standardized test method FDA asked C63 to develop a test method October 2010 Assigned to SC7, Spectrum Etiquette October 2011 Designated C63.27, Chair: Steve Berger Participants from government, industry, academia May 8, 2015 Wireless Electronics and Electrical Medical Devices 65

66 Example wireless coexistence test setup

67 Example wireless coexistence test setup

68 Example wireless coexistence test setup

69 Example wireless coexistence test setup from draft C63.27

70 Example wireless coexistence test setup from draft C63.27

71 Example wireless coexistence test setup from draft C63.27

72 Wireless coexistence conclusions C63.27 development in progress AAMI wireless coexistence TIR in progress Good cooperation and division of labor C63: Test methods AAMI Medical intended use Risk management Guidance on pass/fail criteria May 8, 2015 Wireless Electronics and Electrical Medical Devices 72

73 FDA wireless activities (cont d) Meetings/working with FCC (And also with SAE) on wireless charging of electric vehicles (wireless power transfer) FCC/FDA Joint Workshop on Wireless Medical Test Beds March 31, 2015 May 8, 2015 Wireless Electronics and Electrical Medical Devices 73

74 FDA wireless activities (cont d) Mobile Medical Applications Guidance Those that are not medical devices Those that are medical devices that FDA intends to exercise regulatory discretion Those that are medical devices that FDA plans to regulate May 8, 2015 Wireless Electronics and Electrical Medical Devices 74

75 Experience with EMC information in regulatory submissions Submissions with little or no EMC information Submissions with incomplete EMC information Only certification submitted EMC test report submitted But evidence of conformity with labeling requirements is missing For RF receivers, no indication whether passed immunity in exclusion band or exemption was used May 8, 2015 Wireless Electronics and Electrical Medical Devices 75

76 Experience with EMC information in regulatory submissions (cont d) EMI missing from list of hazards ERP not specified for transmitters Immunity pass/fail criteria were not based on Essential Performance Product-specific pass/fail criteria not specified Test failures No wireless coexistence testing for transmitter / receiver or testing inadequate May 8, 2015 Wireless Electronics and Electrical Medical Devices 76

77 Experience with EMC information in regulatory submissions (cont d) Some submissions include complete EMC information and meet all requirements of referenced standards Some manufacturers go above and beyond the requirements One manufacturer of surgical device controllers worked with chip manufacturer to reduce RF output power of remote control reduce risk of outside wireless detecting and causing problems with system May 8, 2015 Wireless Electronics and Electrical Medical Devices 77

78 Deficiencies in test planning Essential Performance not specified Pass/fail criteria listed, if associated with BS and EP, but EP not specified Pass/fail criteria A/B/C/D specified Intended use environments not specified Default hospital test levels used for all environments (Ed 3) May 8, 2015 Wireless Electronics and Electrical Medical Devices 78

79 Deficiencies in testing Min and max mains voltages not used for EFT/burst; surge; and voltage dips, short interruptions and voltage fluctuations tests (Ed 3) Entire system not included in the test and/or subsystems not simulated adequately Deficiencies in the test report Essential Performance not specified, etc. (see test planning) Photos not legible May 8, 2015 Wireless Electronics and Electrical Medical Devices 79

80 Deficiencies in labeling Statements and warnings omitted Performance determined to be EP Stacking/adjacent warning Special precautions put into service according to the EMC information (Ed 3) Accessories statement and warning Portable and mobile RF communications equipment can affect medical electrical equipment (Ed 3) May 8, 2015 Wireless Electronics and Electrical Medical Devices 80

81 Deficiencies in EMC guidance tables (Ed 3) Guidance tables (four) missing Calculation of equation coefficients e.g.,. not completed Rounding not as specified by Conducted and radiated RF separation distance equations not aligned with compliance levels Compliance level and EMC guidance not modified when higher immunity test levels are used May 8, 2015 Wireless Electronics and Electrical Medical Devices 81

82 Guidance and manufacturer s declaration electromagnetic immunity The Model 006 is intended for use in the electromagnetic environment specified below. The customer or the user of the Model 006 should assure that it is used in such an environment. IMMUNITY test IEC TEST LEVEL Compliance level Electromagnetic environment guidance Portable and mobile RF communications equipment should be used no closer to any part of the Model 006, including cables, than the recommended separation distance calculated from the equation applicable to the frequency of the transmitter. Recommended separation distance Conducted RF 3 Vrms 3 Vrms d = 1, 2 P IEC khz to 80 MHz Radiated RF IEC V/m 80 MHz to 2,5 GHz 3 V/m d = 1, 2 P 80 MHz to 800 MHz d = 2, 3 P 800 MHz to 2,5 GHz where P is the maximum output power rating of the transmitter in watts (W) according to the transmitter manufacturer and d is the recommended separation distance in metres (m). Field strengths from fixed RF transmitters, as determined by an electromagnetic site survey, a should be less than the compliance level in each frequency range. b Interference may occur in the vicinity of equipment marked with the following symbol: (Ed 3) May 8, 2015 Wireless Electronics and Electrical Medical Devices 82

83 Conclusions Medical device EMI continues to be reported Most reports involve active implanted devices Defibrillators Pacemakers Neurostimulators Infusion pumps RF wireless technology in healthcare is proliferating May 8, 2015 Wireless Electronics and Electrical Medical Devices 83

84 Conclusions (cont d) RF Wireless Technology FDA guidances Coexistence FDA participates in many standards activities FDA currently recognizes (among many others) IEC Ed. 3 IEC Ed. 4 Many X and X standards May 8, 2015 Wireless Electronics and Electrical Medical Devices 84

85 Conclusions (cont d) FDA coordinates with FCC on EMC and wireless issues Completeness/quality of EMC information in regulatory submissions varies It saves time and money to get it right the first time! May 8, 2015 Wireless Electronics and Electrical Medical Devices 85

86 Jeffrey L. Silberberg, MSEE Senior Electronics Engineer FDA/CDRH Office of Science and Engineering Laboratories Secretary, IEC SC62A MT23 May 8, 2015 Wireless Electronics and Electrical Medical Devices 86

87 Thank you for your attention! Questions?

88 Appendix Supplemental material

89 An EMC recall case study: EMC conformity gone wrong Date Recall Initiated: March 17, 2008 Date Posted: July 23, 2008 Recall Number: Z Product: Model X extracorporeal blood circulation system Reason for Recall: Stops pumping: Interruption of Model X support may occur when using a Model Y Electrocautery Unit May 8, 2015 Wireless Electronics and Electrical Medical Devices 89

90 EMC recall case study: System details Includes primary and backup pump consoles Was claimed to conform to IEC : 2007 (Ed. 3) Manufacturer claimed system was tested for immunity to electrosurgical units (ESU) / HF surgical equipment Designed to stop and alarm if problem detected with pump motor May 8, 2015 Wireless Electronics and Electrical Medical Devices 90

91 EMC recall case study: Adverse events At least three adverse event reports Argentina (1), UK (1) and Spain (1) System performed OK in OR Patient moved to ICU, was bleeding ESU used in ICU in monopolar coagulate mode Pump stopped and alarmed Motor Fail Required restart, taking several minutes No reported patient injury RF coupled to device through the blood May 8, 2015 Wireless Electronics and Electrical Medical Devices 91

92 EMC recall case study: EMI incident details Manufacturer said: Pump stopping and alarming was OK Performed as intended Recommended user mitigation Switch to bipolar mode Reboot Warning: Don t use Model Y ESU with Model X blood pump May 8, 2015 Wireless Electronics and Electrical Medical Devices 92

93 EMC recall case study: EMI incident details FDA said: Pump is intended to pump blood Pump monitoring system was mistaken No problem with pump motor EMI was detected erroneously as a pump problem Patient at risk during reboot Backup console equally susceptible Further coagulation might be needed Please mitigate via design modification May 8, 2015 Wireless Electronics and Electrical Medical Devices 93

94 EMC recall case study (cont d) Nine hospitals had ONLY Model X blood pump and ONLY Model Y ESU! Recommended using Model Y in bipolar mode only when Model X in use The fallacy of fail-safe Some say that safe failure is OK in hospitals because of the availability of other equipment; however, Other equipment might have the same susceptibility Some hospitals might not have alternatives May 8, 2015 Wireless Electronics and Electrical Medical Devices 94

95 Recall: IEC :2007 considerations Tested for ESU immunity by performing IEC (radiated RF immunity) test down to 150 khz ESU emissions are broadband, IEC is narrowband Could not have met IEC s field uniformity requirement Test lab should have known better than to test down to 150 khz with radiated RF May 8, 2015 Wireless Electronics and Electrical Medical Devices 95

96 Recall: :2007 considerations (cont d) IEC :2007 says that patient simulators should not be grounded PATIENT simulation [from ] The simulator used shall not provide an intentional conductive or capacitive connection to earth during testing, except as otherwise specified in a subclause of this collateral standard. Unintentional capacitance between the PATIENT coupling point and earth should be no greater than 250 pf. May 8, 2015 Wireless Electronics and Electrical Medical Devices 96

97 Standards considerations (cont d) IEC (all editions): PATIENT COUPLING includes via conductive fluids IEC (Ed. 4 and later) includes an annex on testing immunity to ESU May 8, 2015 Wireless Electronics and Electrical Medical Devices 97

98 EMC recall case study Summary Mitigation by design is best Conformance to standards is important Patient simulator requirements of Field uniformity requirements of ESU immunity recommendations of Particular ( Part 2 ) requirements and test methods are needed for ESU immunity of external blood pumps (and other devices) The manufacturer fixed the problem with a software upgrade May 8, 2015 Wireless Electronics and Electrical Medical Devices 98

99 AIM/REG/HCI test method details Minimum and maximum occupied BW Compliance criteria: 8.1 of :2014 IEC methods and modified calibration procedure Calibrate uniform field area using commerciallyavailable signal generator Replace sig gen with custom RFID sig gen and validate at one point HF test levels based on 2.5 cm separation distance LF and UHF test levels based on 20 cm separation distance May 8, 2015 Wireless Electronics and Electrical Medical Devices 99

100 Test specifications RFID SPECIFICATION FREQUENCY TEST LEVEL ISO khz 65 A/m ISO/IEC Type A MHz 7.5 A/m ISO/IEC Type B MHz 7.5 A/m ISO/IEC (ISO Mode 1) MHz 5 A/m ISO/IEC Mode MHz 12 A/m ISO/IEC MHz 3 V/m ISO/IEC Type C MHz 54 V/m ISO/IEC Mode GHz 54 V/m May 8, 2015 Wireless Electronics and Electrical Medical Devices 100

101 RF Wireless Guidance Considerations Information that should be provided to users The specific RF wireless technology type, characteristics of the modulation, and effective radiated RF power Specification of each RF frequency or frequency band of transmission and the preferred frequency or frequency band (if applicable), and specification of the bandwidth of the receiving section of the equipment or system in those bands May 8, 2015 Wireless Electronics and Electrical Medical Devices 101

102 RF Wireless Guidance Considerations (cont d) Information that should be provided to users (cont d) Applicable FCC labeling A warning that other equipment could interfere with the medical device or device system, even if the other equipment complies with CISPR emission requirements. Information about the needed quality of service and security May 8, 2015 Wireless Electronics and Electrical Medical Devices 102

103 RF Wireless Guidance Considerations (cont d) Information that should be provided to users (cont d) Functions and performance of the wireless data transmissions including data throughput, latency, and data integrity Information about any limitations on the number, output power, or proximity of other inband transmitters used in the vicinity that might adversely impact a device s operation May 8, 2015 Wireless Electronics and Electrical Medical Devices 103

104 RF Wireless Guidance Premarket submissions Device description should include Description of wireless technology and functions How the design of the device s wireless functions assures timely, reliable, accurate, and secure data transfer If wireless is used for alarms, alarm description, priority, and how RF wirelessrelated risks are managed/mitigated May 8, 2015 Wireless Electronics and Electrical Medical Devices 104

105 RF Wireless Guidance Premarket submissions (cont d) Device description should include (cont d) Whether other wireless products or devices are able to make a wireless connection to the device. If so, identify them and explain how the medical device functions are protected from adverse effects of such connections May 8, 2015 Wireless Electronics and Electrical Medical Devices 105

106 RF Wireless Guidance Premarket submissions (cont d) Test data should include Tests performed Reference to applicable medical device, RF wireless technology, and EMC standards Explanations for any deviations Operating modes used and explanation of their significance Pass/fail criteria Statement that modifications made to pass testing will be made to production units May 8, 2015 Wireless Electronics and Electrical Medical Devices 106

107 RF Wireless Guidance Premarket submissions (cont d) Labeling should include A summary of the medical device wireless functions and specific wireless technology incorporated into the medical device A summary of the operating characteristics of the wireless technology, effective RF radiated power output and operating range, modulation, and bandwidth of receiving section May 8, 2015 Wireless Electronics and Electrical Medical Devices 107

108 RF Wireless Guidance Premarket submissions (cont d) Labeling should include (cont d) A description of the wireless QoS needed for safe and effective operation A description of the recommended wireless security measures Information addressing wireless issues and what to do if problems occur Information about any wireless coexistence issues and mitigations May 8, 2015 Wireless Electronics and Electrical Medical Devices 108

109 RF Wireless Guidance Premarket submissions (cont d) Labeling should include (cont d) Appropriate EMC and telecommunications standards compliance and test results Appropriate RF wireless communications information such as those required by FCC rules Warnings about possible effects from RF sources in the vicinity of the device (e.g., electromagnetic security systems, cellular telephones, RFID or other in-band transmitters). May 8, 2015 Wireless Electronics and Electrical Medical Devices 109

110 RF Wireless Guidance Premarket submissions (cont d) Labeling should include (cont d) Labeling required by applicable EMC and wireless standards May 8, 2015 Wireless Electronics and Electrical Medical Devices 110

111 A quick search of 2014 reports (cont d) Example mentions of EMI that were NOT confirmed EMI problems (cont d) Implanted neurostimulator for incontinence - The caller was with the patient and trying to interrogate stimulator with clinician programmer and getting telemetry failure message. Caller also states they cannot interrogate stimulator using patient programmer. Caller states they are in room where they typically interrogate devices and were not near EMI (electromagnetic interference). May 8, 2015 Wireless Electronics and Electrical Medical Devices 111

112 A quick search of 2014 reports (cont d) Example mentions of EMI that were NOT confirmed EMI problems (cont d) A critical alarm was heard. The healthcare provider (HCP) thought the pump might have been empty. However, the HCP later interrogated the pump, which revealed that multiple motor stalls occurred, for ~ 3 hours. The stalls only occurred on some days. On [date], the patient was in the emergency room due to the event. The patient did use a microphone/amplifier but not all of the time. The patient s wife was going to try to rule out any electromagnetic interference that could have caused the stalls. The device system was used to deliver compounded baclofen. May 8, 2015 Wireless Electronics and Electrical Medical Devices 112

113 Apparent EMI problem examples (cont d) MDR Report Key , Rec. 10/07/2014 Event description: [Mfr] received information that this implantable cardioverter defibrillator and right ventricular lead exhibited low, out of range shocking lead impedance measurement of 0 ohms detected via the patient remote monitoring system. A review on shock impedance trend revealed a measurement of greater than 200 ohms, but no alert was received. May 8, 2015 Wireless Electronics and Electrical Medical Devices 113

114 Older EMI report examples Implanted pacemaker, in a hospital During breast surgery, the doctor was using the 9900 electrosurgery generator and the patient s pacemaker stopped working. Cardiopulmonary resuscitation (CPR) was used to resuscitate the patient. May 8, 2015 Wireless Electronics and Electrical Medical Devices 114

115 Older EMI report examples (cont d) External pacemaker, public place The device manufacturer reported that while a female patient (age unknown) was being transported by helicopter, the patient s pacing was intermittently interrupted by radio frequency interference. The patient subsequently died. May 8, 2015 Wireless Electronics and Electrical Medical Devices 115

116 Older EMI report examples (cont d) IV syringe pump MDR Report Key Rec March 12, 2007 User and biomedical technician noted excessive 60 cycle interference on the ekg waveform making the waveform unreadable. The biomed tech unplugged all the [model] syringe pumps from ac power and noted that the 60 cycle interference was removed from the ekg monitor. May 8, 2015 Wireless Electronics and Electrical Medical Devices 116

117 Example EMI reports (cont d) Implanted spinal cord stimulator, public place The patient walked through the theft detector at a university library and received a shock that knocked him to the floor. The implanted device was reset to "0" by the shock. The patient sustained no known injury. The device was reprogrammed and it is functioning properly. The health care provider stated that the security system was reportedly set too high. May 8, 2015 Wireless Electronics and Electrical Medical Devices 117

118 Example EMI reports (cont d) Pulse oximeter MDR Report Key Rec January 6, 2003 Upon transporting a pt intra hosp, pulse oximeter failed in battery mode. Personnel switched oximeter to a.c. power. Hosp investigation team tried to duplicate the malfunction. Fully charged oximeter from ICU would not malfunction when a two-way radio was keyed next to it. But, when using oximeter with slightly discharged battery, malfunction was duplicated. Keying two-way radio approx one foot [30 cm] from unit created an internal reset problem and keying two-way radio adjacent to oximeter caused complete shutdown. Manufacturer s initial report suggests effects of EMI contributed to the failure and this may be related to a low battery/poor battery circuitry. May 8, 2015 Wireless Electronics and Electrical Medical Devices 118

119 Example EMI reports (cont d) Infusion pump MDR Report Key Rec February 21, 2006 The facility reported an infusion pump with over infusion. Reportedly a displayed rate changed during pt infusion. The pt's cell phone rang and the nurse at the bedside noticed that rate of pitocin was displayed at 120ml/hr rather than the prescribed rate of 20 ml/hr. The change was noticed in less than one minute and there was no harm to the pt. A new pump was put on the pt. According to the hosp. rep, the event history did not show any buttons being pressed for the rate change. May 8, 2015 Wireless Electronics and Electrical Medical Devices 119

120 Example EMI reports (cont d) Infusion pump MDR Report Key Received June 19, 2006 The facility reported a pump that stopped infusing during patient use. The pump was infusing heparin, at which time the patient's family member used a cell phone in close proximity to the pump. The pump then stopped infusing. There was no patient injury or medical intervention according to the hospital rep. May 8, 2015 Wireless Electronics and Electrical Medical Devices 120

121 Case Studies Conducted EMI Ultrasound Artifacts Slide courtesy Dara McLain Reproduced Spectrum Analysis of a noisy power supply from a patient monitor Actual May 8, 2015 Wireless Electronics and Electrical Medical Devices 121

122 Case Studies HVAC Controllers Slide courtesy Dara McLain Broadband noise caused by variable speed controllers used in the air handling system. An adjustment on the controller provided by the manufacturer significantly reduced the interference. Facilities had this new system installed in a newly constructed wing and 1) did not review EMC documentation, and 2) did not notify Clinical Engineering of this installation. Interference began at the same time as installation of this new HVAC system, and continued for 11 months before mitigation was achieved. May 8, 2015 Wireless Electronics and Electrical Medical Devices 122

123 Case Studies - HVAC Control Circuitry Relay Slide courtesy Dara McLain Normally Open Normally Closed Due to relays in HVAC circuitry that were either not rated for the current through them, or incorrect for the circuit design, the plastic body melted and caused the normally closed condition to be slightly open, resulting in arcing. There were two main hallways with an HVAC relay circuit for each room, more than 60 relays that any one of them could produce broadband interference of up to 15 minutes in length. May 8, 2015 Wireless Electronics and Electrical Medical Devices 123

124 Case Studies Patient Room Hair Dryer Slide courtesy Dara McLain In-room hair dryers found during a pre-installation RF Survey. Not all hair dryers emitted noise. Defective hair dryers functioned [in]correctly. The proposed wireless system would not have functioned properly due to this noise. May 8, 2015 Wireless Electronics and Electrical Medical Devices 124

125 Case Studies Automated Door Mechanism Slide courtesy Dara McLain Broadband noise from automated door into the NICU. These solenoids had degraded over time. Replacement was recommended. May 8, 2015 Wireless Electronics and Electrical Medical Devices 125

126 Case Studies Lighting Dimmers Hallway lighting controlled by automated dimming at specified times. System cabinets were not equipped with any shielding, though the system documentation called for it. All dimmer switches are potential broadband sources. A broad frequency span shows the arcing characteristics of the dimmers. Only the weak signals are affected at the time the noise occurs. Recommendations: Install shielding on the dimmer system control cabinets. Slide courtesy Dara McLain May 8, 2015 Wireless Electronics and Electrical Medical Devices 126

127 Case Studies Elevator Controls Doctor s office building elevator motor control circuitry* with excessive noise emissions (only one of two elevator control circuits emitted noise). This noise was conducted onto the power line. It radiated as well, but the building had no wireless systems. *These elevators had brushless motors. Slide courtesy Dara McLain May 8, 2015 Wireless Electronics and Electrical Medical Devices 127

128 Case Studies Co-channel Occupancy Slide courtesy Dara McLain Two wireless systems programmed to the same frequencies in use, interfering with each other. Unknown to Clinical Engineering, the offending system field service tech reprogrammed the system transmitters. The affected system company resolved the issue at the customer s expense. May 8, 2015 Wireless Electronics and Electrical Medical Devices 128