The starting point of the usability engineering is to draft a preliminary use specification. Its purpose is to collect enough information necessary to help planning and conducting user research activities (e.g. observations, interviews, surveys).
The medical device use specification is a document prescribed by IEC 62366 – 1 clause 5.1 with a precise structure that must be delivered to the regulatory authorities. It is the foundation for defining and designing the user interface of the device as its elements aid in identifying the known and foreseeable hazards and hazardous situations related to the user interface.
At this early initial stage, it contains some necessary information:
· the identified user groups which will be interviewed;
· the defined use environment which will be inspected;
· the identified intended medical indications of the device.
•Pliability and rigidity of the catheter
–if present, mandrin handling
•Visibility of the guidewire marks
The use specification is refined over time, even in a post-market phase, while more knowledge is gained through user research, and its level of detail and accuracy increases. New user groups might be discovered during the user research. If so, these would be added to the use specification and can trigger new user research activities.
IEC 62366-1:2015 requires the use specification of a medical device to contain at least the following elements:
· intended medical indication; which are conditions or disease(s) to be screened, monitored, treated, diagnosed, or prevented.
· intended patient population to whom is though the device
· intended part of the body or type of tissue applied to or interacted with;
· intended user profile;
· intended use environment;
· operating principle of the device.
Additional information can be present as these can be helpful to support subsequent usability engineering activities. They are as follows:
· anticipated tasks of users in the operation of the medical device;
· the set of user needs derived from the anticipated task.
Much or all of the use specification is likely to be input to design and development of the device, in particular of the user interface. Moreover, as the user interface development process proceeds, the use specification should be reviewed and updated as needed.
While preparing the use specification, expert reviews can be a rapid means to identify the strengths and weaknesses of a comparable user interface. Such reviews could concern an expert examining a medical device and citing its strength and weaknesses in a brief memorandum or the engagement of several experts to review independently the medical device, identify potential improvements, prioritise the improvements, and then report their consensus findings.
Therefore, the realisation and updating of the use specification is an essential and iterative step in identifying potential use errors and to improve the characteristics of the user interface.