The medical treatment of patients is associated with risks. These risks are considerable and also come from medical devices themselves. Inadequate usability of medical devices can lead to misuse and thus to harm or even death of patients. This also applies to software as a medical device. For this reason, manufacturers of medical devices are obliged to carry out a development process that is linked to usability engineering. This article gives an overview about the requirements and how to fulfill them.
- What requirements does the MDR place on the usability of medical devices?
- How do I implement the usability requirements of medical devices?
- What changes have been made to IEC 62366?
- How is the usability engineering process structured?
- Why is usability engineering also economically useful?
- How do I perform usability engineering for medical software?
What requirements does the MDR place on the usability of medical devices?
The European Medical Device Regulation (EU) 2017/745 (MDR), whose date of application is May 26, 2021, gives great importance to the usability of medical devices. Direct references can be found in particular in Annex I, which describes the general safety and performance requirements.
According to this, the manufacturer shall, among other things:
- reduce risks due to ergonomic features of the product and the product environment (patient safety),
- take into account the technical knowledge as well as the health condition of the users (user safety),
- design the medical device in such a way as to reduce the risk of injury through the physical and ergonomic characteristics of the product,
- design and manufacture measuring, checking or indicating devices in accordance with ergonomic principles, and
- design medical devices for use by laypersons accordingly and provide easily understandable information.
In addition, there are a number of requirements for the instructions for use. These can be found mainly in Chapter III of Annex I, which describes the “Requirements regarding the information supplied with the device”.
Even after the product has been placed on the market, the assessment of usability does not end. The manufacturer must record any incidents in the course of clinical follow-up, report them as part of post-market-surveillance (PMS) and improve the usability of the product.
How do I implement the usability requirements of medical devices?
The IEC 62366-1 standard describes a usability engineering process aimed at ensuring an acceptable application risk for a medical device. The application risk of a medical device is reduced if it is easy to operate, learn and use.
To this end, the standard requires a usability engineering process to be carried out that covers all aspects of transport, storage, installation, operation, maintenance, repair and disposal of the medical device. The process contains measures for risk control with regard to the design of the user interface and for the provision of safety information.
The process documentation takes place in the Usability Engineering File. There is an additional technical report on the IEC 62366-1 standard, which explains in more detail how usability engineering can be designed (IEC TR 62366-2). The report is more comprehensive than the standard and covers not only usability with regard to safety, but also, for example, accuracy, task completion, efficiency or user satisfaction.
Since quality management according to ISO 13485, which is obligatory for the manufacturer, is closely related to usability, this standard also plays a role here. There is a direct reference above all to Chapter 7 (Product Realisation) and to the subsections on design and development.
What changes have been made to IEC 62366?
The current version of the IEC 62366 standard is not the first edition. Therefore, the main changes to the previous version should be taken into account:
- With the publication of IEC 62366-1:2015, the previous IEC 62366 standard was divided into two parts. The normative part IEC 62366-1 specifies a process for usability engineering for medical devices with the aim of increasing product safety. The technical report IEC TR 62366-2 explains the implementation and application of the process described in Part 1.
- The current version of IEC 62366-1 aligns the requirements and terminology more closely with those of the U.S. Food and Drug Administration (FDA).
- The previously independent chapters “Accompanying Documents” and “Training and Training Material” have been integrated into the entire usability engineering process.
How is the usability engineering process structured?
First, the manufacturer must create a Use Specification. This contains, for example, the medical indication, the user group, the patient group and the body region. For example, it can make a difference whether a ventilator is to be used in the ambulance or on the station.
This is followed by a systematic analysis of the user interface with regard to safety-critical properties that may result in use errors. Subsequently, the manufacturer identifies hazards and hazardous situations as part of the risk analysis of the medical device. At this point, the standard advises to include findings from comparable medical devices.
Subsequently, the manufacturer determines and describes hazard-related usage scenarios which contain all tasks, their sequences and the corresponding severity of the damage. This is followed by the preparation of a User Interface Specification, which also includes testable technical requirements as well as information as to whether accompanying documentation and specific training are required.
The manufacturer shall then evaluate the user interface. The IEC 62366 standard describes various procedures and planning steps for this purpose. Finally, based on the evaluation results, the manufacturer implements the usable design of the user interface of the medical device.
Why is usability engineering also economically useful?
A usable medical device also has advantages outside of regulatory requirements. In this way, the manufacturer receives valuable information at an early stage, which can shorten the time to market. The risk of design defects in the user interface, the correction of which can be time-consuming and expensive, is lower.
In addition, usability engineering as part of mandatory risk management should have an overall positive effect on the quality of the product file and its evaluation.
A further advantage is the higher acceptance of the user by more user-friendliness. This can result in competitive advantages. User training is also easier if the manufacturer focuses on intuitive operating concepts.
Overall, less advice and support from the manufacturer should be required in order to communicate operating concepts and processes to users. Users can also correct errors more easily themselves.
How do I perform usability engineering for medical software?
Although usability is an integral part of medical device development and the importance of medical device development has increased even further as a result of the MDR, many manufacturers and developers of medical software are not very familiar with it.
This concerns both the development of independent medical software and embedded software that is part of a medical device. Numerous questions arise with regard to the practical implementation of usability engineering:
- How do I set up an efficient usability engineering process for my software?
- What is the relationship between usability engineering, risk management and clinical evaluation?
- At which points in the product life cycle does usability engineering play a role?
- What is the concrete usability engineering process for software with regard to planning, use specification, risk analysis, user interface specification and evaluation?
Manufacturers should not neglect the usability of a product. It is part of risk management, which in turn is part of regulatory requirements.
A consistently operated usability engineering process leads to higher user satisfaction. Application errors occur less frequently and the handling of the product by users becomes more efficient.
In order to align product functions with user needs, usability should be taken into account at an early stage of development.
In addition, it has advantages to have usability engineering supervised by experts who are not involved in the actual production of the product. As externals, they do not yet know the product and are therefore not burdened with expectations and experiences. As a rule, usability specialists are also better acquainted with the required processes and documentation.