Page 192 - Safety Risk Management for Medical Devices

CHAPTER 19

Risk Evaluation

Abstract
ISO 14971 requires the manufacturer to determine if the residual risks posed by the medical device
are acceptable using the criteria defined in the risk management plan. Three methods of risk evalu-
ation are presented: qualitative, semi-quantitative, and quantitative.
Keywords: Risk evaluation; qualitative; semi-quantitative; quantitative

ISO 14971 [3,7] requires the manufacturer to determine if the residual risks posed by
the medical device are acceptable when compared against the criteria defined in the
risk management plan (RMP). Although preliminary risk evaluations can be done
before the completion of design, what matters is the final evaluation of the residual
risks of the medical device, after all the Risk Controls have been implemented.
ISO 14971 [3] requires that the manufacturer evaluate the acceptability of residual
risk for:
• each Hazard
• each Hazardous Situation
• overall

The Standard [3,7] does not prescribe a method for risk evaluation and allows the
manufacturer to choose an appropriate method. Nor does the Standard specify
whether the same or different criteria are to be used for the evaluation of individual
residual risks, and the overall residual risks. The choice is left up to the manufacturer.
Depending on which method of risk estimation is chosen: qualitative, semiquanti-
tative, or quantitative, the evaluation method varies.

19.1 APPLICATION OF RISK ACCEPTANCE CRITERIA

For some of the Hazards that a medical device presents, it may be possible to identify
an applicable product safety standard that offers specific requirements for safety. ISO
14971 [3,7] considers compliance with such a standard an indication of acceptability
of risk for that particular Hazard. According to Ref. [22], harmonized standards
should be sought first. If no harmonized standard is available, then other national or
international recognized standards or publications should be considered.

Safety Risk Management for Medical Devices r 2018 Elsevier Ltd.
DOI: https://doi.org/10.1016/B978-0-12-813098-8.00019-2 All rights reserved. 171