Page 99 - Safety Risk Management for Medical Devices

78 Safety Risk Management for Medical Devices

the risks of the yet undeveloped device will outweigh its benefits. It is far less expen-
sive to cancel a project early, than to embark on the project and have to cancel it late
in the design and development phase.
Basically, the PHA is an early version of the Hazard Analysis Report (HAR). In
fact, it uses the same Risk Assessment and Control Table (RACT) template. The
main difference is that the PHA has access to little actual design information and uses
a lot of estimations. Also, the PHA is not a living document. It is only used as guid-
ance to start the project, and also as a reference for the HAR. But it is the HAR that
lives on for the life of the product.
It is highly recommended that a PHA be performed especially for new and novel
product development.

12.3.2 Methodology
Inputs to the PHA are:

• System requirements
• Concept architecture
• Intended use, intended user, and intended use environment
• Risk acceptability criteria (from the Risk Management Plan (RMP))
• Clinical Hazards List (CHL)
• Harms Assessment List (HAL)

If the System is a new version or an iteration of a product that has been previously
analyzed for risk, then it is advisable that the previous risk analysis be used as an input
to the new analysis.
In the following sections the PHA workflow is described.

12.3.2.1 Safety characteristics
Given the intended use, intended user, and intended use environment for the System,
and given the concept architecture and System requirements, identify those qualitative
and quantitative characteristics that could affect the safety of the medical device.
Consider the technologies used in the device, and how they can contribute to
Hazards. Where appropriate identify the operational specification limits within which
the device can be operated safely.
Include user interface (UI) characteristics that could be related to safety.
Annex C of ISO 14971 [3,7] provides questions that can be useful aids in this effort.

12.3.2.2 Identify System Hazards
Using the knowledge gained in Section 12.3.2.1 examine the CHL. Identify the
Hazards that are relevant to the System. Exclude the remaining Hazards in the CHL
from the analysis and provide rationales for why any Hazard is excluded.