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Overview of FDA's New Human Factors Program Plan: Implications for the Medical Device Industry

History of FDA’s Involvement With Human Factors

The Food and Drug Administration (FDA) has been engaged in human factors-related activities and projects to improve patient safety since 1975. Initial FDA efforts began when staff joined voluntary consensus standards committees engaged in writing performance and safety standards for medical devices. Many of these performance and safety standards included human factors engineering design requirements. The need for a human factors design guideline for medical devices first became apparent to the Center for Devices and Radiological Health (CDRH) when Center staff worked with the American National Standards Institute (ANSI) Committee Z79 to write a standard for anesthesia gas machines. More than 80% of the requirements in that American National Standard related to human factors. Many of the human factors design requirements that ANSI Z79 had struggled to generate were applicable to more than just anesthesia gas machines and, unbeknownst to the committee, were already described in a military standard (MIL-STD-1472 Human engineering design criteria for military systems, equipment and facilities.) CDRH staff suggested to the then chairman of ANSI Z79, Dr. Leslie Rendell-Baker, that he contact AAMI to propose establishing an AAMI Human Factors Committee to write a human factors design guideline for medical devices similar to the military standard. The ANSI/AAMI HE48-1993 guideline, Human factors engineering guidelines and preferred practices for the design of medical devices, was the result.

Additionally, over the last 10 years, CDRH has commissioned a number of human factors studies of specific medical devices; assisted in the production of a number of educational films on human factors directed at the central venous catheters, hemodialysis, and anesthesia health care communities; written articles for the medical device trade press; and delivered lectures on human factors at manufacturer workshops. The Center also published a booklet entitled Write it Right, which gives advice about writing medical device labels and instructions for use.

Focus on Human Factors

Human factors is not new to CDRH. What is new, however, is the Center's recent decision to focus more attention and resources on its human factors program. This is prompted by a growing body of evidence that shows medical device use error is an even more significant factor in patient deaths and injuries than was previously thought. It is increasingly clear that errors in the use of medical devices result in hundreds, if not thousands, of patient deaths and serious injuries each year.

People make mistakes. Even the most experienced, conscientious, and disciplined people make mistakes. When these people are health care givers and the mistakes involve their use of medical devices, the results too often are patient death or serious injury. Poor human factors designs of devices is a significant contributing cause. Too many devices employ features or operate in ways that encourage error. In addition, many devices lack features known by human factors experts to be effective in protecting against or reducing the chance of error. The Center believes that much more can and should be done to design medical devices that better match users' needs, expectations, and abilities.

CDRH is convinced that manufacturers must pay more attention to human factors at the earliest stages of product design and development, when user input can make a difference. A commitment by company management to ensure that the design team take the necessary steps to involve users early in the design and development process is essential. It is simply not possible for designers to predict the sort of problems that the typical user will have with a device and the kind of misinterpretations and errors that will occur. A range of typical users, including novices and occasional users, should be engaged to help designers develop design input requirements, evaluate concepts, test prototypes, and validate the final design.

The process for incorporating human factors into design and development is well-established and tested. It benefits manufacturers, users, and patients. The benefits from an improved human factors design substantially outweigh the costs. The Center is concerned that the manufacturers who incorporate human factors into product development may be the exception rather than the rule. FDA wants all medical device manufacturers to profit from implementing a sound human factors program during product design and development. The Safe Medical Devices Act of 1990 (SMDA) gave us a means to accomplish that goal.

Premarket Activities

The SMDA provided FDA with explicit authority to add preproduction design validation controls to the good manufacturing practices regulation for medical devices. These new design controls will require manufacturers to establish and maintain procedures to control and verify that a design appropriately addresses the needs of device users. In complying with these new design controls, design teams will have many options. There is no one prescription because manufacturers must have the flexibility to tailor a human factors program that makes sense for their organization and the type of products and product line they supply. FDA will issue guidance on the subject but has no intention of dictating a process. However, we expect that process to be appropriate for the device, adequately documented, and adhered to.

Our Office of Device Evaluation (ODE) has required human factors assessments of medical devices, for example, in reviewing patient labeling for several home use medical devices and in evaluating a reclassification petition and investigational device exemption supplements for two cardiac devices. ODE will be focusing more attention on human factors in the future. Human factors guidance documents related to device exemptions and 510(k) premarket notifications are presently being considered for some higher priority medical devices.

The Center is developing a system to rank medical devices in priority order for human factors efforts. The system considers the probable frequency and seriousness of errors associated with the use of these devices, the extent to which these errors could be minimized, and the number of patients at risk. Its use will ensure that CDRH resources are directed at devices that cause the highest mortality and morbidity rates and are amenable to being made safer through application of established human factors design practices and principles. Experts in medical device design and use, including representatives from the device industry, health professionals, engineers, and human factors professionals, will participate with our staff in the ranking process. These experts will review a subset of devices that are known or believed to have a significant potential to injure patients as a consequence of use error. The system will be pilot tested this year. The Center will seek outside review of the priority scheme before it is finalized.

Postmarket Activities

The Center's human factors program will also have a postmarket focus. The SMDA requires hospitals, nursing homes, ambulatory surgical facilities, and outpatient treatment and diagnostic facilities to report device-related patient deaths and serious injuries. Device design may have contributed to errors that occur. The SMDA also authorizes CDRH to require manufacturers to conduct postmarket surveillance studies for certain devices. Rational concerns about patient deaths and injuries resulting from use error caused by poor user-device interface design could serve as a basis for the Center requiring such studies. Studies would seek to determine the incidence and outcome of use error and the extent to which user-device interface design contributed to the problem.

Updated December 3, 1996

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