Less uncertainty from the FDA, and a smoother 510(k) submission process, is always a good thing. That’s why most medical device manufacturers (MDMs) support the new FDA guidance document released on June 22 that will improve the safety of medical devices by conducting more human factors engineering.
The 37-page document, entitled “Applying Human Factors and Usability Engineering to Optimize Medical Device Design,” states that its “recommendations are intended to improve the usability of devices to reduce use error, injuries from medical devices, and product recalls.”
The FDA requires that manufacturers conduct risk analyses to determine the risks associated with device use. “If analysis indicates there is a moderate to high risk of use error, then the manufacturer should perform human factors testing,” states the draft document (this testing, however, is required for certain products that are already viewed as higher risk, such as infusion pumps).
According to the document, the sample size for a human factors study may need to be expanded if the device has users with distinctly different characteristics, such as use responsibilities, age ranges, skill sets, or experience levels. If this is the case, validation-testing activities should include 15 from each major user group. “Requiring that sample size for these studies is expected to be a concern for industry, due to the expense and logistics of conducting validation usability studies that test actual users under realistic conditions, user production or pre-production models,” says Virgil Dickson, editor at FDAnews.
Section 8 of the draft document, entitled “Mitigation and Control of Use-Related Hazards,” states that “use-related hazards that are identified through analytical approaches or formative evaluations should be designed out or controlled prior to submitting the device for HFE/UE validation testing. Use-related hazards often require a combination of mitigation and control strategies. The following list presents the order of overall priority for applying strategies to control or mitigate risks of use-related hazards:
• Modify the device design to remove a hazard or reduce its consequences: For example, making the user interface intuitive and ensuring that critical information is effectively communicated to the user can reduce the likelihood of or eliminate certain use-related hazards. If hazards cannot be eliminated, the design should, to the extent possible, reduce their likelihood and the severity of any consequences.
• Make the user interface, including its operating logic, error tolerant: When errors occur during device use, such as users pressing an adjacent key on a keypad, the device should act to preclude a hazardous outcome. Safety mechanisms such as physical safety guards, shielded controls, or software or hardware interlocks will make the design more tolerant of errors that users might make.
• Alert users to the hazard: When neither design nor safety features will eliminate a use-related hazard or adequately mitigate the consequences, the device should detect the condition and provide an adequate warning signal to users.
• Develop written procedures and training for safe operation: If it is impossible to eliminate hazards through any of the previous strategies, or to enhance other control or mitigation strategies, then written procedures, labeling enhancements, and training for safe operation are the remaining options.”
This is good protocol when it comes to redesigning devices and improving user interactions to mitigate possible hazardous situations—it’s also a helpful view of how the FDA expects MDMs to proceed at this sometimes-challenging stage of device development.
The FDA is currently soliciting comments and suggestions on the draft. Send comments to docket No. FDA-2011-D-0469 by September 19, 2011. The complete draft document can be accessed at: www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm259748.htm#b.
The final document will replace “Medical Device Use-Safety: Incorporating Human Factors Engineering into Risk Management,” which took effect in July 2000.
Even though this may be viewed as another layer of regulation by the FDA, it’s a good thing because it presents a clear picture of what the FDA expects regarding the integration of human factors and usability engineering in the design and development process—which also means a smoother and faster 510(k) process and safer medical devices.