Author: Dan Sterling | Date: February 7, 2018
Medical device hazard analysis is a fundamental requirement of ISO 14971 risk management. Hazard analysis entails identification of hazards from possible occurrences or “hazardous effects”. These hazardous events could stem from the environment or usability of the device from human factors. After an assessment of the possible failures in the products or “causes”, steps should be taken to do a comparison of the risks’ costs to its benefits. This is known as a “top-down” approach that reviews the component of the product at the end.
In the case the cost is greater than maintaining a residual risk—actions should be taken to mitigate or eliminate this risk. In the case the benefit is greater than perceived cost—actions should be taken to ensure that stakeholders are aware of the residual risks that they are being exposed to during use, why they are necessary to the medical device, and how they should be handled. There are two major co-dependent factors used in determining whether the risks the medical device poses are acceptable. On one axis there is probability of hazardous event’s occurrence, or the likelihood of this event happening. On the other axis there is the evaluation of the severity of the event, or how risky the consequences are.
The most common approaches to top-down hazard analysis in medical device development include Fault Tree Analysis (FTA) and Hazard Analysis and Critical Control Point (HACCP). The two are similar in approach, but visually FTA is seen as a convenient way to estimate probabilities of frequency. At the top of the tree lies the hazardous event that poses a risk, which then branches down to various levels of factors that cause this event to happen that need to be addressed. This method is based off of logic gates to target all causation events or “gates”, are necessary to make the top level event occur.
In the initial steps of development, it can be difficult to know specific hazardous events that might occur, but there are still high-cost baseline hazardous events that could pose risk during development that must be considered. This is useful for determining the best course of action when selecting materials, developing monitors, controls, and other design features for the product. Thus FTA is primarily risks of various alternatives.
HACCP has a specific seven step process in structuring the hazard analysis. In addition to identification, HACCP targets critical points and limits. Once done, a specific system is established to monitor these critical control points and verify that the HACCP system is working effectively while establishing a record-keeping system.
The same perspective is applied throughout the intricacies of production to post-production of medical devices to ensure there are considerations for life threatening risks from malfunctions and misinformation. Often a risk matrix will be created with the aforementioned probability of occurrence, set in relativity to severity based on the company’s risk-acceptability criteria. The result is a constantly improving and low cost product.
At Sterling Medical Devices we embed hazard analysis with our human factors engineering process. To learn more about our human factors engineering, visit here.
February 7, 2019
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