At first glance, the term hazard appears quite intuitive to understand. According to the dictionary, it is the source of danger. But it is not so easy to precisely define it when doing risk analysis for your medical device in the context of ISO 14971. 

ISO 14971 defines it simply as a "potential source of harm". But what does that mean?

It is not that this definition is incorrect. The problem is that according to this definition nearly everything could be a hazard.

Is hazard a thing, an activity, an event or a condition?

In simple terms, this definition is not sufficiently precise for us to apply in practice.

As a result, there is a lot of confusion in the medical device industry and many mistakes are made during hazard analysis. 

Why does it matter, you ask?!

The main reason is that if we don't correctly identify hazards associated with our medical device in both normal and fault modes, then we can't effectively identify and implement appropriate risk control measures. 

Here are a few examples of common points of confusion

Use of Failure Modes and Effects Analysis (FMEA) is very common in medical device industry. Often, it is the only technique used for risk analysis.

But an FMEA is not sufficient to appropriately analyze risks in the context of ISO 14971. You may be surprised to learn that FMEA is not hazard analysis!

It is not uncommon to find that many people in the industry incorrectly equate the effect(s) of a failure mode to hazard(s). This is not necessarily correct in many situations. For example:

Damaged packaging is not a hazard

If a medical device is intended to be supplied in a sterile condition, protected with a sterile barrier packaging, then there may be damage to this barrier packaging due to one or more failure modes. This may lead to a breach of sterility and contamination with microbiological agents such as bacteria, virus and parasites. 

However, this is not a hazard but an initiating/trigger event that may lead to a sequence of events and hazardous situation, where the patient or user is exposed to the real source of harm (i.e. microbiological agents). 

Weak or damaged battery in an AED is not a hazard

It is very important for an automated external defibrillator (AED) to deliver sufficient electrical energy at the point of use. That is why, the battery needs to hold sufficient charge at all times. However, if the battery is weak or damaged due to one or more failure modes, it does not mean that it is a hazard (i.e. a source of harm). It is a condition which may lead to harm following a sequence of other events. The real source of harm in this case is insufficient/low amount of electrical energy at the point of use. 

Missing or incorrect label is not a hazard

Labeling is very important in the medical device industry because it must comply with strict regulatory requirements. However, missing or incorrect label, by itself, is not a hazard. If the label is missing, or if it provides incomplete, inaccurate or ambiguous information, then it may lead to a sequence or combination of events, that may eventually lead to harm from one or more other real sources of hazards. 

That is why using an FMEA for the purpose of identifying hazards and hazardous situation is not an effective way to do hazard analysis. 

Also keep in mind that you cannot use an FMEA to identify hazards in the normal mode of operation. 

So, how do you identify the real hazard?

In simple terms, you have to drill down further to identify the "real" hazard that most directly leads to harm through exposure in a hazardous situation. 

Watch the brief video above for a few examples. Other examples of different types of hazards that may be applicable for your medical device are provided in Annex C of ISO 14971:2019. 

Conclusions

1. A simple definition of the term hazard as a "potential source of harm" is not sufficiently precise for application in practice
2. Failure modes and their effects are not necessarily hazards
3. Using FMEA for the purpose of identifying hazards, sequence of events and hazardous situations is not effective
4. Examples of different types of hazards are provided in Annex C of ISO 14971:2019.

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