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Risk Analysis Techniques 113

disease; what part of the body, etc. Use Specification is about the context of use of the
medical device, which includes:
• Intended use
• Intended user
• Intended use environment

12.8.3 UMFMEA Workflow
In the following sections the workflow for UMFMEA is described. The workflow
corresponds to the template that is provided in Appendix B—Templates.

12.8.3.1 Set scope
Explicitly define the scope of analysis. For UMFMEA the scope should include the
System and the users who would interact with the System, e.g., patient, physician, or
service personnel. External influences to the scope of analysis are considered as causes
to Failure Modes. For example, loud noises, dim ambient lighting, etc.

12.8.3.2 Identify primary and secondary functions
As in the DFMEA and PFMEA, identify the primary and secondary functions of the
subject of analysis. Since UMFMEA analyzes the entire System, this step identifies the
primary and secondary functions of the medical device. Primary functions are those
that achieve the main mission of the System. All other functions are secondary. For
example, if a pacemaker logs the history of therapy that it has delivered, the primary
function of the pacemaker would be pacing, and the secondary function would be
logging therapy history.

12.8.3.3 Analyze
Analysis of the System for use-failures requires knowledge of the System Use-
Scenarios and their constituent tasks. A formal usability engineering task analysis is a
good basis for the UMFMEA. If a formal task analysis is not available, at a minimum,
inventory the Use Scenarios and actors. A graphical representation like Fig. 12.14 is a
handy way to communicate and confer with your team to make sure a complete
inventory of the use scenarios and actors is achieved.
Next, for each identified Use Scenario, list the tasks and step actions by the
Actors. This can be tabular or a graphic flow chart. For each step action, hypothesize
the ways in which the step action could be done incorrectly, and the causes thereof.
Consider the distinctions that are described in Section 12.8.1. Use hypotheses such as:
user is unable to see/hear, interpret, press, etc. Log this information in the UMFMEA
spreadsheet.