The FDA and a number of other regulatory agencies are primarily concerned with the safety and effectiveness of medical devices. For a device to be safe and effective, the device user must be able to perform some important tasks. One thing is clear, a medical device should be able to fulfill its function effectively, otherwise it is meaningless.
An X-ray machine is capable of producing pictures of bones (intact, cracked, or broken); an insulin pump is capable of delivering insulin into subcutaneous tissue at a set rate; and a minimally invasive surgical anastomosis is capable of placing an anastomotic staple in the desired location. If the user does not know how to start the X-ray machine, how to set the rate of basal insulin delivery, and how to load the anastomotic staple onto the anastomosis, then none of the intended uses of these three medical devices can be realized.
In countries that require approval of medical devices for marketing, the corresponding regulatory agencies have requirements for functional validity. In other words, decades ago, the medical device market (both in the US and in other countries) was full of "quack" devices that did not fulfill their intended use well, or at all.
In the face of these worthless and potentially harmful devices, we are pleased that medical device manufacturers are now being asked to demonstrate that their devices are both safe and effective.
Let's discuss this topic in the context of usability testing. In summative usability testing, you're trying to find evidence that the user can perform high-risk tasks without making potentially harmful use errors. At the same time, you should be looking for evidence that the user can successfully complete the task.
Thus, just proving that your medical device is low risk is not enough to get regulatory approval. The user must also be able to perform tasks related to the effectiveness of the device.
Usability testing experts choose tasks that are safety-relevant because there is a possibility that harm could result simply from the user's inability to perform a task. Consider resuscitating a patient in ventricular fibrillation with an automated external defibrillator. What happens if the patient cannot be shocked due to confusion about how to operate it?
On the one hand, the device will not harm the patient because the patient is already in a very dangerous situation. However, not being able to perform the shock would also cause the patient to miss out on life-saving treatment. Is this outcome just a matter of the device being ineffective? Or is it a safety issue? Or is it both. We think it's both.
Emergo is a medical device registration consulting firm with in-depth knowledge of medical device usability testing and evaluation, and if you have any questions about medical device registration compliance, please visit the emergo website
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