Avalon Fetal Monitor - Risk of Inaccurate Ultrasound-Derived Fetal Heart Rate Monitoring

Starting date:
October 9, 2019
Posting date:
October 9, 2019
Type of communication:
Dear Healthcare Professional Letter
Subcategory:
Medical Device
Source of recall:
Health Canada
Issue:
Important Safety Information
Audience:
Healthcare Professionals
Identification number:
RA-71217

Last updated:

Audiences

Healthcare professionals including obstetricians, gynaecologists, family physicians practicing in obstetrics, neonatologists, nurses, midwives, and biomedical and clinical engineers.

Key messages

  • Health Canada analyzed reports of inaccurate Doppler ultrasound-derived fetal heart rate (FHR) monitoring associated with the use of the Avalon Fetal Monitor.  Health Canada found that there is insufficient evidence to establish a link between the use of the Avalon Fetal Monitor and adverse fetal outcomes.  
  • While the Avalon Fetal Monitor Instructions for Use (IFU) contained detailed information regarding the correct use of the device, some important instructions were not prominently emphasized. In order to help further reduce the risk associated with inaccurate monitoring, Health Canada has worked with the manufacturer to improve the IFU to ensure that important instructions are appropriately highlighted.
  • Healthcare professionals are advised that changes have been made in the Avalon Fetal Monitor IFU to highlight the following important instructions:
    • Check the mother’s pulse periodically during monitoring and compare this with the FHR signal. Beware of mistaking a “doubled” maternal heart rate (MHR) for FHR.
    • Always confirm fetal life before using the monitor.
    • The simultaneous monitoring of MHR (preferably, the maternal ECG) and the fetal heart rate is encouraged.
    • Whenever possible make use of the cross-channel verification (CCV) feature.
  • Additionally, healthcare professionals are advised that starting with software version Revision J.3, an audible tone is provided to help users identify potential coincidence between all monitored heart rates.

Issue

Reports of inaccurate FHR monitoring, including outcomes of stillbirth and low Apgar score, have been reported with the use of the Avalon Fetal Monitor in Canada and internationally. Although Health Canada’s review of the available information found that inaccurate FHR monitoring has been observed in some cases, there was insufficient evidence to establish a link between the use of the Avalon Fetal Monitor  and adverse fetal outcome. A review of the literature shows that all continuous FHR monitors that use Doppler ultrasound to derive FHR have the potential to show inaccurate readings.

Products affected

Medical Device Licence Name Manufacturer Medical Device Licence Numbers
Avalon Fetal Monitor FM20 Philips Medizin Systeme Boeblingen GmbH 70451
Avalon Fetal Monitor FM30 Philips Medizin Systeme Boeblingen GmbH 70452
Avalon Fetal Monitor FM40 Philips Medizin Systeme Boeblingen GmbH 77190
Avalon Fetal Monitor FM50 Philips Medizin Systeme Boeblingen GmbH 77094

Background information

The Avalon Fetal Monitor is a continuous electronic fetal monitoring device, which uses a cardiotocograph (CTG) to allow healthcare professionals providing obstetrical care to analyze FHR changes during labour and delivery, and to institute timely intervention to avoid intrapartum hypoxic and/or ischemic injury.

The Avalon Fetal Monitor models FM20, FM30, FM40 and FM50 are used for monitoring FHR and MHR in labour and delivery rooms, and in antepartum testing areas. While features vary among the Avalon Fetal Monitor models, all four models have the same device software.

Maternal artefact is common in Doppler ultrasound-derived FHR tracings and is a limitation associated with the use of CTG technology, nonspecific to any particular manufacturer. Many fetal monitors include signal modulation and autocorrelation algorithms, and use wider ultrasound beams to decrease FHR signal loss. However, such features can also increase the likelihood of accidental recording of the MHR. Literature reports suggest that any continuous FHR, from any Fetal monitor that uses Doppler ultrasound for the determination of FHR, could show inaccurate FHR.

The Avalon Fetal Monitor manufacturer initiated a recall in 2009 to amend the IFU by including an addendum with supplemental information to further help users recognize any potential inaccuracies in the readings and to mitigate risks arising from inaccurate FHR readings or the misinterpretation of tracings. This addendum has since been incorporated into all subsequent versions of the Avalon Fetal Monitor IFU. This recall did not involve product removal from the market.

In 2014, the manufacturer released an updated software version of the Avalon Fetal Monitor. Starting with software Revision J.3, an audible alarm tone with the coincidence alarm is provided to help users identify potential coincidence between all monitored heart rates.

In 2017, Health Canada received incident reports related to the Avalon Fetal Monitor and inaccurate FHR monitoring. As a result, Health Canada conducted a safety review to assess the potential safety risks associated with this device.

At the time of the review, 10 Canadian incident reports had been received by Health Canada for the Avalon Fetal Monitor in which stillbirth or potential need for immediate care at birth were described. Internationally, there were also reports of stillbirth, neonatal death, poor neonatal outcome, and unnecessary caesarean section associated with the use of Avalon Fetal Monitors. While Health Canada found that inaccurate FHR monitoring had occurred in some cases, there was insufficient information in the reports to establish a relationship between the incidents and the use of the Avalon Fetal Monitor.  Additionally, Health Canada found no evidence of malfunction of the Avalon Fetal Monitor in the reported incidents.
 

Who is affected

Information for consumers

The Avalon Fetal Monitor is a medical device licensed in Canada to monitor the heart rate of a mother and her unborn baby or babies during labour and delivery. This device helps healthcare professionals identify possible fetal distress and provide timely intervention, if needed.

There have been Canadian and international reports of inaccurate fetal heart rate monitoring, some of which were associated with stillbirths and babies with potential need for immediate care at birth, with this device. There was no evidence of any device malfunction in connection with the reports.

Health Canada conducted a safety review to assess potential safety risks. Although Health Canada found that inaccurate fetal heart rate monitoring had occurred in some cases, there was not enough information to establish a link between the use of the device and the incidents. 

Patients should contact their healthcare professional for further information.

Information for healthcare professionals

Healthcare professionals are advised that the following important instructions have been highlighted in the Avalon Fetal Monitor IFU in order to help further reduce the risk associated with inaccurate monitoring:

  • Check the mother’s pulse periodically during monitoring and compare this with the FHR signal. Beware of mistaking a “doubled” MHR for FHR.
  • Always confirm fetal life before using the monitor.
  • The simultaneous monitoring of MHR (preferably, the maternal ECG) and the fetal heart rate is encouraged.
  • Whenever possible make use of the cross-channel verification (CCV) feature.
  • Periodically compare the mother’s pulse with the signal coming from the monitor’s loudspeaker to ensure that you are monitoring FHR. A doubled or elevated MHR should not be mistaken for FHR.
  • The audible alarms should not be relied upon for remote monitoring since the alarm systems of the monitor and those of the connected obstetrical information and surveillance system are independent and not synchronized.

Lastly, healthcare professionals should be aware that starting with software version Revision J.3 released in 2014, an audible tone is provided to help users identify potential coincidence between all monitored heart rates.

Action taken by Health Canada

In order to help further reduce the risk of inaccurate monitoring Health Canada has worked with the manufacturer to improve the device’s instructions for use and ensure that important instructions are appropriately highlighted.

Health Canada is also communicating this important safety information to Canadians via the Recalls and Safety Alerts Database on the Healthy Canadians website. This communication will be further distributed through the MedEffect™ e-Notice email notification system, as well as social media channels including LinkedIn and Twitter.

Health Canada will continue to monitor safety information involving fetal monitors, as it does for all health products on the Canadian market, to identify and assess potential harm. Health Canada will take appropriate and timely action if and when any new health risks are identified.
 

Report health or safety concerns

Health Canada’s ability to monitor the safety of marketed health products depends on healthcare professionals and consumers reporting adverse reactions and medical device incidents. Any cases of serious or unexpected adverse incidents associated with the use of Avalon Fetal Monitors or any other device should be reported to the manufacturer or Health Canada.

Any suspected adverse incident can be reported to:

Regulatory Operations and Enforcement Branch
Health Canada
Address Locator: 2003D
Ottawa, Ontario K1A 0K9
Telephone: Regulatory Operations and Regions Branch Hotline: 1-800-267-9675

The Health Product Complaint Form (FRM-0317) can be found on the Health Canada Web site. 

For other health product inquiries related to this communication, contact Health Canada at:

Marketed Health Products Directorate (MHPD)
E-mail: hc.mhpd-dpsc.sc@canada.ca
Telephone: 613-954-6522
Fax: 613-952-7738