Why incorporate human factors early in medical device design?
By Adam R Shames
A common reason for a medical device company to call us for the first time is that they have received a response letter from the Food and Drug Administration (FDA) requiring them to run a human factors study. They are usually surprised because they have never had to consider human factors before. Why should a company incorporate human factors early on in their medical device design process, and not just as a reaction to an FDA letter? It is simple, because it will create a better, more effective device and save them time and money.
Many designers claim their device is intuitive and people will be able to use it with common sense. Unfortunately, you cannot assume a person can use a medical device until you see a person actually using it safely in real-life or a simulated-use environment.
The reality is that people are fallible. Highly educated healthcare professionals make medical mistakes that result in far too many deaths than we should find acceptable. The Department of Health and Human Services stated that in one month 0.6% of Medicare beneficiaries (~6367 patients) had adverse events classified as “should never occur in a healthcare setting.” An example is the administration of aspirin to a patient with a low platelet count that led to pulmonary hemorrhage and death, which was judged as clearly preventable. In 2000, the Institute of Medicine concluded that preventable adverse events cause between 44,000 and 98,000 deaths in hospitals each year and newer estimates have only increased this number.
Employing human factors engineering (HFE) processes helps reduce the number of preventable deaths; therefore, it is important to incorporate HFE in the medical device design process.
A simple definition of HFE is that it is the scientific discipline concerned with the understanding of interactions among people and other elements of a system, and it applies theory, principles, data, and other methods to design in order to optimize human well-being and overall system performance. All HFE practitioners working with products are interested in how the intended users use the product in its intended use environment. However, there are many specializations within HFE, one of which focuses on medical devices, our expertise.
When medical device HFE practitioners talk about “users” we are talking about caregivers, healthcare professionals, and patients themselves. That means we must simulate quite diverse use environments, from hospital ICUs to living rooms. Is there something about the ICU lighting at night that might make using a device problematic? Then we would test the usability of the device in the correct amount of light to simulate that environment. If the patient is the user, then we have to take into account any medical conditions the patients might have that could affect their interaction with the device. For example, can a person with arthritis in their hands actuate the device that contains an arthritis medication? Our focus is on whether a device can be used safely and effectively by the intended users.
Unlike other HFE fields, an aspect of HFE in medical device design in the United States is that we function under regulation from the FDA. In 2011, The FDA published a draft guidance document, “Applying Human Factors and Usability Engineering to Optimize Medical Device Design,” that represents their current thinking on HFE. For validation studies, we follow this guidance on user group size, decay of learning times, etc. HFE work in most fields is not regulated. The FDA requirement for HFE testing on medical devices is moving the ball down the field toward safety. Remember that medical errors happen all the time and hospitals are complex systems filled with humans.
So why should manufacturers incorporate HFE early on in their medical device design process? It comes down to a few important reasons. Until you see a user using your product in the correct use environment, you really do not know what is going to happen. This is a learning process and actually is part of the fun. It is also crucial to making the safest and most effective device. You do not want to discover a problem late in development—perhaps even years into development—when changes to the device can be costly and impractical. It is easier, cheaper, and a more dynamic process to identify early in development what changes are required and then be able to make those appropriate device alterations.
You do not want to be surprised during your validation testing. And if you learn something during that testing and there is a fix that will reduce risk, then you may be required to make that change. By now, you know what comes next—you test the device again! Do yourself and your medical device a favor and incorporate HFE early and often in the design process.