Page 83 - Safety Risk Management for Medical Devices

62 Safety Risk Management for Medical Devices

Table 11.1 Example of Harms Assessment List
Severity Class
FDA Catastrophic Critical Serious Minor Negligible
ID Harm Code (%) (%) (%) (%) (%) Total (%)
Harm.1 Burn (thermal 1757 1.5 4.0 66.8 19.8 7.9 100
tissue
heating)
Harm.2 Cerebral Fluid 1772 0.1 2.3 60.4 35.8 1.4 100
Leak
Harm.3 Hemorrhage, 1891 2.5 19.0 31.7 46.8 0.0 100
intracranial
Harm.4 Infection 1930 0.9 2.2 72.1 18.3 6.5 100

After the first pass of cleanup, route the list to subject matter experts. For example,
clinicians, clinical investigators, or R&D engineers who have experience with similar
devices. After the second round of reviews, the list should be ready for approval and
use in your risk management process.
You may find that some Hazards may need to be stratified. For example, cessation
of breathing for 10 seconds, versus 2 minutes, versus 5 minutes could have dramati-
cally different harms. In such cases the same Hazard could be cited n times, each with
a different qualification.
The CHL is a living document which is kept up to date. If at any time a new
Hazard manifests that was not previously in the CHL, revise and update the CHL.
This is how the claim of completeness can be made—that at any given time, the CHL
is as complete as possible.

11.6 HARMS ASSESSMENT LIST

Another pivotal tool in the BXM method of risk management is the HAL. The HAL
is a list of all the potential Harms that could result from the use of the System under
analysis. Table 11.1 shows an example of a partial HAL.
Note: The data in Table 11.1 is fictitious—do not use for actual analysis.
The HAL provides P 2 , the probability of sustaining Harm in a Hazardous Situation.
In other words, it is assumed that the Hazardous Situation has already happened.
The HAL model presented here is inspired by ISO 14971 [3,7]. Note the follow-
ing in the construct of the HAL:
• Harms are physical injury.
• For each Harm five P 2 numbers are provided, one for each Severity class.
• Sometimes no Harm occurs in a Hazardous Situation. In this example, the
lowest Severity class: Negligible includes the “No Harm” outcomes.