Page 142 - Safety Risk Management for Medical Devices

CHAPTER 13

Safety Versus Reliability

Abstract
There is a general misperception that reliability and safety are the same, and that a reliable device
is a safe device. While this is sometimes true, it is not a universal truth.
Keywords: Safety; reliability

There is a general misperception that reliability and safety are the same, and that a
reliable device is a safe device. While this is sometimes true, it is not a universal truth.
A simple example is a scalpel. A reliable scalpel will cut tissue every time, but if it
cuts the surgeon’s hand, there is a safety issue. A converse example—imagine a
medical device that has so many safety mechanisms that it frequently shuts down to
avoid causing injury. The device may be very safe, but also very unreliable. Typically,
when safety mechanisms have high sensitivity but low specificity, we encounter safe
but unreliable Systems.
The role that reliability plays in safety is when both attributes are aligned. Take the
example of a stent. An unreliable stent that dislodges, or fractures, would be also an
unsafe stent. When safety and reliability are aligned, improved reliability also improves
safety.

Safety Risk Management for Medical Devices r 2018 Elsevier Ltd.
DOI: https://doi.org/10.1016/B978-0-12-813098-8.00013-1 All rights reserved. 121