Page 84 - Safety Risk Management for Medical Devices

Risk Management Process 63

• The totals of all the five P 2 numbers add up to 100%. This means all possibili-
ties are accounted—from nothing to death.
• The Harm outcomes are the aggregate of all potential circumstances, e.g., for
Harm.4 in Table 11.1, if some infections receive medical care and some don’t,
the cited probability of Harm numbers account for both possibilities.
The creation of a HAL requires foresight and good judgment. Harm outcomes
depend on many factors. The same Harm would have different outcomes on
different patient populations, under different conditions, etc. For example, con-
sider the Harm of electrocution, meaning injuries due to electric shock. The volt-
age and current of the source, the impedance of the skin of the person, the
location of electrical discharge on the body are all factors on the severity of the
Harm. The creator of the HAL may choose to create multiple lines for the Harm
of electrocution, e.g.,
Electrocution due to:

• Exposure to 100 200 V
• Exposure to 200 400 V
1
• Exposure to 400 V
• Exposure to unprotected hand
• Exposure to gloved hand
• Exposure while user is standing in water
• etc.
Application of this strategy to all the Harms could create a very large HAL.
Alternatively, all the various circumstances of electrocution could be aggregated into
one line—electrocution. This option would offer less precision in the determination
of the risk of Harm, but is more practical with respect to the size of the HAL. A
midway method would be to consult KOLs about the most likely levels of Harm, and
stratify the Harm only to those most likely levels. Striking the right balance is the art
of risk management.
Remember that only a qualified person (e.g., an MD) can assign severities to
Harms.

11.6.1 How to create a Harms Assessment List

There are two methods by which a HAL can be created:
Method 1—Using published data
Method 2—Using expert opinion

Each method is detailed as follows.