A medical device being single-fault safe is when a piece of medical electrical equipment remains free of unacceptable risk during its expected service life under single fault conditions. But the challenges to achieving that state in healthcare can be daunting.
Designers and developers of medical devices are aware of the relevance and risks involved in single faults, which must be avoided in all states of operation. However, the dynamics of development, technological progress, and the normative framework require in-depth expertise—especially for innovative equipment.
From a regulatory and technical perspective, it is very clear why single-fault safety should be ensured in electrical, electronic, and programmable electronic medical equipment (E/E/PE systems). For example, the drug dose delivered by an infusion pump must never be too high or too low, and a neonatal incubator for premature newborns must safely and reliably keep the temperature within narrow limits, never going above or below those limits even in the case of a malfunction.
However, in practice, the types of equipment posing additional challenges for manufacturers are mostly far more complex, including X-ray devices, MRI scanners, or machines for extracorporeal membrane oxygenation (ECMO). To make matters worse, technical standards are not always unambiguous. This is also made clear by Interpretation Sheet IEC 60601-1:2005/AMD1:2012/ISH1:2021, published in March 2021 by the International Electrotechnical Commission (IEC).
Read the full article at Medical Device + Diagnostic Industry.