FDA Issues Draft Guidance on Human Factors and Usability Engineering to Optimize Medical Device Design

• By: Staff Editor
• Date: November 11, 2011

The FDA issued new draft guidance on using human factors and usability engineering to optimize medical device design.

• The risks analysis results show that there might be a moderate to high risk of use error or
• If a manufacturer is modifying a marketed device due to use error as a CAPA.

1. Submission of human factors information is required (for example, as a special control);
2. Submission of human factors information is recommended in a specific guidance for a device type and the manufacturer cannot justify forgoing such testing; or
3. On a for-cause basis if it is the least burdensome method to address FDA’s concerns regarding human factors issues.

• All components of a device with which the user interacts, such as controls and displays (i.e., those parts of the device that users see, touch, and hear).
• Including the device labeling, which includes package labels, any instructions for use in user manuals, package inserts, instructions on the device itself, and any accompanying informational materials.

1. Device Users
2. Device Use Environments
3. Device User Interfaces

• Device use requires physical, perceptual, or cognitive abilities that exceed the abilities of the user;
• The use environment affects operation of the device and this effect is not recognized or understood by the user;
• The particular use environment impairs the user’s physical, perceptual, or cognitive capabilities when using the device to an extent that negatively affects the user’s interactions with the device;
• Device use is inconsistent with user’s expectations or intuition about device operation;
• Devices are used in ways that were not anticipated; or
• Devices are used in ways that were anticipated but inappropriate and for which adequate controls were not applied.

• Identify anticipated use-related hazards and unanticipated use-related hazards, and determine how hazardous use situations occur;
• Develop and apply strategies to mitigate or control use-related hazards; and
• Demonstrate safe and effective device use through human factors validation testing.

•  Device users
  • Identification of the end-users of the device (e.g., patient, family member, physician, nurse, professional caregiver)
  • The level of training users will have and/or receive
  • User characteristics (e.g., functional capabilities, attitudes and behaviors) that could impact the safe and effective use of the device
  • Ways in which users might use the device that could cause harm
• Device use environment
  • Hospital, surgical suite, home, emergency use, public use, etc.
  • Special environments (e.g., emergency transport, mass casualty event, sterile isolation, hospital intensive care unit)
  • Interoperability with other devices
• Device user interface
  • E.g., functions, capabilities, features, maintenance requirements
  • Indicated uses 

• Analytical approaches
• Formative evaluations

• Analysis of the expected use of new devices and of available information about the use of similar devices; and
• Employment of methods that can include contextual inquiry, interview techniques, function and task analysis, and heuristic and expert analyses.

• Should focus initially on the major issues that preliminary evaluations indicate are most likely to have an impact on use safety and effectiveness and those areas where design options for the user interface are not final
• Can be expanded to include certain aspects of the use environment or specific sub-groups of users depending on the results of preliminary evaluations
• Methods should be chosen based on the need for clarification prior to developing final design specifications and based on resources available

• Cognitive walk-through:
  • In a cognitive walk-through, a user or small group of users are guided through a structured process of using a device, which may be represented as a simple mock-up or early-stage prototype.
  • Participants are questioned and encouraged to provide feedback on difficulties they notice while using the device.
  • Evaluators can collect subjective information from participants about their thought processes, mental models, and perceived workload when using the device.
• Simulated Use Testing:
  • Simulated use testing, (also called usability testing and, occasionally, user testing) involves systematic collection of data from users (participants) using a device (or device component or system) in realistic situations.
  • Data are obtained in a variety of ways, including subjective user feedback, manual and automated measures of user performance, and direct observation.

• Modify the device design to remove a hazard or reduce its consequences
• Make the user interface, including its operating logic, error tolerant
• Alert users to the hazard
• Develop written procedures and training for safe operation