This is a continuation of part 1 and looks at more usability requirements.
“Devices shall be designed and manufactured in such a way as to remove or reduce as far as possible; a) the risk of injury, in connection with their physical features, including the volume/pressure ratio, dimensional and where appropriate ergonomic features, and d) the risks associated with the possible negative interaction between software and the IT environment within which it operates and interacts.”
This requirement states that the medical device has to be developed to remove or minimise specific risks discussing harms, environmental conditions, contact, software, interference, ingress and maintenance. Section a) details risks of injury (harm) in “connection with their physical features” which includes ergonomic features. This would be proven though risk assessment of the interaction between the user/person and the ergonomic features of the medical device. In this, we would add “user interfaces” since these are the parts of the device that the user/person will have to interact with. Section d) is an interesting requirement in that it details the “risks with the possible interaction between software and the IT environment”. Connectivity between the medical device and any external power and information source is what this requirement is asking the manufacturer to understand and make as safe as possible. Many medical devices are now internet enabled, data is stored “in the cloud” or on servers, power is more often wireless or through other interacting devices and products. Considering how users/persons interact with the device safely and in a non-negative manner is thus important and now a requirement to have evidence to show compliance to. In an early stage usability study, emotions – both positive and negative can be simulated, discussed and design solutions evaluated. So, if the device arrives with the incorrect plug on its power cord, or the software in the device is incompatible with a hospital IT system, then these situations can be designed out.
“Devices shall be designed and manufactured in such a way that adjustment, calibration, and maintenance can be done safely and effectively.”
This requirement focuses on the management of the device – adjustment, calibration and maintenance, if they are applicable. The requirement states to ensure that these activities can be performed “safely” and effectively”. This can proven post-launch by actual use, but pre-launch this may involve testing out whether these activities are indeed safe and effective. Here, inclusion in usability and human factors studies would be sufficient to generate adequate data to prove compliance.
“Devices that are intended to be operated together with other devices or products shall be designed and manufactured in such a way that the interoperability and compatibility are reliable and safe.”
This requirement looks at systems – where the device being CE Marked is part of a larger system. The device that needs to operate with other devices or products needs to do so safely, reliably with optimal compatibility and interoperability. Again, this can be proven by evaluating the system as part of usability or human factors studies, not just the device.
“Any measurement, monitoring or display scale shall be designed and manufactured in line with ergonomic principles, taking account of the intended purpose, users and the environmental condition in which the devices are intended to be used.”
This requirement states to ensure that ergonomic principles are involved in the design and manufacturing of the device – one that has any measurement, monitoring or display scale. By definition, this requirement asks to focus on the intended purpose, users and the use environment – all parts of the usability and human factors engineering process.
“Devices shall be designed and manufactured in such a way as to facilitate their safe disposal and the safe disposal of related waste substances by the user, patient or other person. To that end, manufacturers shall identify and test procedures and measures as a result of which their devices can be safely disposed after use. Such procedures shall be described in the instructions for use.”
This requirement focuses on the disposal of the device, it’s packaging and related waste substances. For hospital-based devices, this will be an element where usability and human factors used in development would research current practices and procedures and proven safety in theory. It is only when the user, the patient, or other person, who is not in a controlled use environment such as at home, does this requirement become important to further understand. It is not sufficient to assume the user will dispose of the device, its packaging and related waste substances safely – evidence that this will occur should be sought, ideally through expert review, testimonies, user research and usability evaluation.
“The function of the controls and indicators shall be clearly specified on the devices. Where a device bears instructions required for its operation or indicates operating or adjustment parameters by means of a visual system, such information shall be understandable to the user and, as appropriate, the patient.”
With this requirement, it is obvious that the focus is on labeling – ensuring the controls and indicators used are clearly defined and obvious to the user. To ensure that these are understood by the user and/or patient, it makes sense to use usability data to show user comprehension and therefore to prove compliance to this requirement, usability testing could be performed. In addition, where it is discussing the use of a visual system, this would refer to a graphical user interface such as a touchscreen, display or software-based device. Any software where a visual interaction is required, usability testing could help in proving that the information is safe and usable.
“Devices for use by lay persons shall be designed and manufactured in such a way that they perform appropriately for their intended purpose taking into account the skills and the means available to lay persons and the influence resulting from variation that can be reasonably anticipated in the lay person’s technique and environment. The information and instructions provided by the manufacturer shall be easy for the lay person to understand and apply.”
This requirement is very focused around the human factors of the user – the abilities and disabilities they may have if they are a lay person. Lay people are often the user or the patient for non-hospital based devices (home healthcare devices frequently). The requirement wants manufacturers to look at the use environment as well as the user, and to ensure they fit into the intended purpose of the device. In addition, it states to ensure that any instructions, IFU’s, User Manuals, websites, digital instructions are comprehendible by lay persons. This can be proven in usability testing and with the US-based FDA regulations for Human Factors, this level of testing has been around since early 2016 as a requirement. This shows a harmonisation between the European requirements and the USA requirements.
“The medium, format, content, legibility, and location of the label and instructions for use shall be appropriate to the particular device, its intended purpose and the technical knowledge, experience, education or training of the intended user(s). In particular, instructions for use shall be written in terms readily understood by the intended user and, where appropriate, supplemented with drawings and diagrams.”
In this requirement, the regulations require manufacturers to focus on ensuring any instructions are able to be again comprehendible by the user (See 22.1), and rather than be just words, include drawings and diagrams. Adding content such as these should enable higher comprehension of tasks and activities required to use the device and to maintain it until it is not required any longer. Often we see Instructions for Use that are very heavily textual, and we recommend the use of illustrations, drawings and diagrams where the instruction itself is long-winded, complex or clinical in nature. But, there is a balance to be had since the instructions should be suited to the user. A clinician would expect to be reading about clinical instructions, clinically-based warnings and precautions, surgical techniques etc., where they are likely to be text heavy. Illustrations may help, but their use may be limited. With lay persons who are not clinically trained, then more illustrations, drawings and diagrams make sense since you cannot predict the intelligence, language capability or location of the user or patient. Therefore, describing tasks in drawings and diagrams often enables a higher level of comprehension with this type of user. For the team at THAY Medical, we have been incorporating this level of human factors since incorporation, and now it is a requirement. It shows we have been performing a best practice and we will continue to do so!
If you have any questions, please do not hesitate to contact THAY Medical. We would love to hear from you.
The staff at THAY Medical