Page 101 - Safety Risk Management for Medical Devices

80 Safety Risk Management for Medical Devices

At this point the PHA is ready to serve its purpose and answer the following
questions:

1. Can the System be built such that its risks are acceptable?
This is to advise the management on whether they should commit
resources to design and development of the medical device. Using the risk
acceptability criteria in the RMP evaluate the overall residual risks of the
System. If the risks in all severity classes are acceptable, the answer to the ques-
tion will be affirmative. But if the risks in one or more of the severity classes
come out to be unacceptable, then investigate with the RMT, and R&D to
determine whether the team believes that with additional future Risk
Controls, they can feasibly bring the System risk down low enough so that in
the end, the overall risks of the medical device become acceptable. If they can,
then again the answer to the question is affirmative. Else, the answer to the
question is negative and the project should not be started.
Some factors may give you early warning of potential future problems. For
example, if the concept for an implantable device requires the use of a toxic
metal such as nickel or mercury, you could anticipate the possibility that in the
end the residual risk of the product may be unacceptable.
2. What are the most safety-critical aspects of the System?
The answer to this question helps to focus resources on the most important
safety-critical aspects of the System. Look for any Hazardous Situation which
has a risk in the unacceptable zone. They should be the highest priority areas
for the Design and Development tram. If all the risks of all the Hazardous
Situations are acceptable, then make a subjective judgment on how to priori-
tize them. For example, you could see how close any Hazardous Situation is to
the unacceptability boundary, and prioritize by the distance to unacceptability.

12.4 FAILURE MODES AND EFFECTS ANALYSIS

FMEA is a systematic method of exploring the ways in which an item or process might
potentially fail to achieve its objective, and the effects of such failures on: the performance
of the system, or process, or the environment and personnel. FMEA is a forward reason-
ing process, also referred to as bottom-up, or inductive analysis. The FMEA technique
was originally developed by the US military in 1949 as a reliability analysis tool. Later, it
was used by NASA in many space programs. Today, many industries, in particular the
automotive industry, use this analytical tool to improve the quality of their products.
There are different types of FMEA processes serving different purposes. The BXM
method adapts the FMEA for the benefit of medical device risk management and uses