Recently with the new regulations, standards and guidance there is an emerging emphasis on the application of usability engineering to medical devices. Historically, manufacturers of active medical devices, including software should be familiar with the application of usability engineering during product development.
It’s important to note that usability engineering shall be applied to all medical device, not exclusively active devices. This is evident and can be clearly identified in the documentation within the regulation, standards and guidance document.
MDR (EU) 2017/745
By close reading of the MDR, EU regulators stressing the application of usability engineering is eminent.
- Article 7 Claims:
“In the labelling, instructions for use, making available, putting into service and advertising of devices, it shall be prohibited to use text, names, trademarks, pictures and figurative or other signs that may mislead the user or the patient with regard to the device's intended purpose, safety and performance by:
- ascribing functions and properties to the device which the device does not have;
- creating a false impression regarding treatment or diagnosis, functions or properties which the device does not have;
- failing to inform the user or the patient of a likely risk associated with the use of the device in line with its intended purpose;
- suggesting uses for the device other than those stated to form part of the intended purpose for which the conformity assessment was carried out.”
Article 7 sets clear requirements for the labeling, instructions for use, informing the user and/or the patient about risk associated with use product claims and intended purpose. All these activities and outputs are part of usability engineering.
- Annex I General Safety & Performance Requirements, e.g.:
- General Requirement 3.(c): estimate and evaluate the risks associated with, and occurring during, the intended use and during reasonably foreseeable misuse.
- General Requirement 5: In eliminating or reducing risks related to use error, the manufacturer shall:
- reduce as far as possible the risks related to the ergonomic features of the device and the environment in which the device is intended to be used (design for patient safety), and
- give consideration to the technical knowledge, experience, education, training and use environment, where applicable, and the medical and physical conditions of intended users (design for lay, professional, disabled or other users).
From the above examples it is now clear the EU regulators wants manufacturers of all medical devices to considers their product claims and subject devices to Risk Management including use error (and reasonably foreseeable misuse, please continue to read).
ISO 13485:2016
In the latest quality management system standard, we can read the following:
- Definitions 3.4 complaint
written, electronic or oral communication that alleges deficiencies related to the identity, quality, durability, reliability, usability, safety or performance of a medical device that has been released from the organization’s control or related to a service that affects the performance of such medical devices.
Please note that usability is explicitly included in the definition (and in the previous :2012 version it was not).
ISO 14971:2019
Also, the recent update of ISO 14971 gives more attention to use related risks.
- Definition 3.5 reasonably foreseeable misuse
use of a product or system in a way not intended by the manufacturer, but which can result from readily predictable human behavior.
This definition broadens the scope of usability engineering to also include use error and associated risks related to abnormal use. - Definition 3.30 use error
A definition of use error is now included in the standard.
IEC 62366-1:2015
But what about ‘passive’ medical device, such as catheters, application pasts, such devices do not have ‘Essential Performance’ as defined for electrical devices or a user interface in the sense of a computer screen or buttons, dials, adjustable controls etc. Ok, but still, they have an intended use, there can be use errors made, there can be (clinical) functions related to safety. Moreover, when performing the appropriate Risk Management steps, a training for using the device can be deemed necessary, the labeling is defined, information for safety (warning symbols, warnings and contraindication) is defined.
Information for safety that relates to usability needs to be subjected to the Usability Engineering process and the Instructions for use is part of the user interface. And information for safety, including instructions for use is considered part of the User Interface of the device.
Recently, I was involved in the case of Continuous Positive Airway Pressure (CPAP) tube. An applicable product standard for that device is ISO 80601-2-74:2017. Clearly a CPAP tube does not have a user interface in the classical sense, but still the standard specifically defines user functions related to safety (usability!), such as: reprocessing, connecting it to mask and humidifier interface ports.
Another example I recently worked on is the case of a Tooth Mousse used by patients with e.g. risk of dental caries, clearly a ‘passive device’ without a ‘user interface’. But still the performance of the mousse is strongly dependent of the application of it, i.e. how it is used. Imaginable, the information for safety and the instructions for application are in the Instructions for Use and need to be validated for proper usability (determine that the information is perceivable, understandable and supports correct use).
MEDDEV 2.1.7 Rev 4
One of the key changes in the MEDDEV 2.7.1 Rev.4 Clinical Evaluation: a Guide for Manufacturers and Notified Bodies is that Evaluators should determine if sufficient clinical evidence is available to support the following, see par. 6.1.:
- the intended purpose described in the information materials supplied by the manufacturer (including for all medical indications);
- the clinical performance and benefits described in the information materials supplied by the manufacturer (including, for example, any claims on product performance and safety);
- measures for risk avoidance and risk mitigation described in the information materials supplied by the manufacturer (including, for example the declaration of the residual risks,
- contraindications, precautions, warnings, instructions for managing foreseeable unwanted situations);
- the usability of the device for the intended users and the suitability of the information materials supplied by the manufacturer for the intended users (including, if applicable, for lay or disabled persons);
- Instructions for target population groups (including, for example, pregnant women, pediatric populations).
Basically, this paragraph in the Rev.4. wraps-up most subjects I mentioned above, that you need to evaluate in a Clinical Evaluation Report.
PMS/PMCF
The manufacturer shall proactively collect and evaluate clinical data when conducting PMCF (as part of the Post-Market Surveillance (PMS) plan. In MDR ANNEX XIV part B 6.1. one of the aims of Post Market Clinical Follow-up (PMCF) is defined as: “identifying possible systematic misuse or off-label use of the device, with a view to verifying that the intended purpose is correct”.
With the processes in place of proactively collecting Usability related data via PMCF and by conducting trending in PMS, we have now closed the loop of evaluating the suitability of the device for its intended use by continuously evaluating the safety, performance and effectiveness of the device, Including usability. Now you know why Usability Engineering is applicable for all medical devices.
Summarizing
The loop of developing and maintaining the safety and effectiveness of any medical device, with respect to Usability Engineering can be summarized with the following info-graphic:
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