Electromedical device manufacturers have been dealing for some time with issues related to the electromagnetic compatibility of electromedical equipment and systems, both regarding the disturbances emitted and the ability to withstand external environment disturbances without alterations in the performance.
Surgical tables activated during procedural steps, unexpectedly triggered defibrillators, dosage changing infusion pumps, ECG results that change during procedural steps, these are all situations that should never occur! For this reason, devices and electromedical systems must be able to provide the essential performance required, not only keeping the general electrical and usability risks low, but also ensuring that interferences with other equipment in the environments in which they are used do not generate potential sources of danger. Electromagnetic interferences apply to all types of energy of this species, considering both the energy radiated through the air (or other means such as the walls), or the one conducted through power lines or signal lines.
If the IEC 60601-1 standard determines the general requirements, the basic safety tests and the performance of the electroMedical Devices, the electromagnetic disturbances are controllable by observing the “collateral” IEC 60601-1-2 standard.
The 2014 revision of the latter cancels and replaces the previous version of 2007, and it represents the fourth edition of a standard that has become more and more important over the years, especially in view of the developments that electronics have undergone in terms of radio frequency communication.
The most significant changes compared to the previous edition of 60601-1-2 include the following items:
- defining the immunity test levels according to the provided, classified and harmonized use environments in accordance with IEC 60601-1-11 (not just professional environments in the medical field but also other environments);
- new test level parameters to improve the electromedical equipment and systems safety when radio frequency (RF) communication equipment is used closer to an electromedical device than recommended;
- specification of immunity test and immunity test levels based on potential entry points for equipment or electromedical system disturbances;
- specification of immunity test levels based on the reasonably foreseeable maximum level of electromagnetic disturbances in environments of intended use, with a resultant higher immunity test level than that of the previous edition;
- better harmonization with the risk concepts of basic security and essential performance, including the deletion of the term “life-supporting”.
The current fourth edition includes a guide to determine the levels of immunity testing for particular environments, the guidelines on safety risk management, the essential performance of electromagnetic disturbances and instructions on identifying the criteria for acceptance or rejection of immunity levels.
According to standard 60601-1-2, the manufacturer is responsible for designing and performing the necessary verifications to meet the technical requirements recognized as optimal. The manufacturer must also maintain a specific control in terms of risk management associated with the use of its own equipment. In particular, the manufacturer is associated with all the responsibilities related to special situations that may arise during equipment or analyzed electromedical system use. Clearly, it is up to the producer to disclose the necessary information to the operators so that the equipment use can always be safe during its presumed lifetime. Moreover, standardization bodies specified that, for certain types of equipment or electrical systems, the requirements included in IEC 60601-1-2 may be modified by the vertical product standards special requirements.
Electromagnetic Compatibility (EMC) of a device or system requires design activities to be considered as part of the device’s design and development stages, both with reference to interference towards and with other devices (EMI) and to disturbances in the surrounding environment (EMD). These aspects, mainly invasive and present in ordinary situations of any operating environment, cannot be addressed with extemporaneousness and improvisation.
As far as decisions of the European Community are concerned, it is worth stressing that standard EN 60601-1-2:2015 has been implemented and recognized in the harmonized standards list.
It replaces the version issued in 2007 and the subsequent 2010 amendment, accepting an overlap period of both versions until December 31, 2018. After this date, devices registered according to the 2007 under review standard should be able to overcome the new performance required to maintain the presumption of conformity to the expected essential requirements.
At the same time, it is worth noting that the US Food & Drug Administration already expects compliance with this standard: considering the particularity of devices to be used in a non-professional environment (at home, but also in schools, hotels, airports, museums …) and the risks associated with the particular conditions that may arise in these areas, the FDA issued a specific guideline that can be used as a further reference for design.
Until 2019, such standard will remain unchanged, as shown in the IEC site where the Stability Date is included, a time reference within which no changes are planned. On the other hand, a series of integrations, which are expected by the end of 2019, are currently underway, which will probably lead to an amendment.
Paride Bruni
Do you want to keep up to date with Thema’s work? Subscribe to our newsletter!