Study of human factors may eliminate errors
By Daniel L. Welch, PhD, CPE
Human Factors Engineering Consultant
Washington, DC
Human error is inevitable in any health care situation. It will happen in health care systems just as it does in all other complex systems, and no measure of attention, training, dedication, or punishment is going to stop it.
But the discipline of human factors engineering (HFE) can help. HFE has been dealing with the causes and effects of human error since the 1940s. Originally applied to the design of increasingly complex military aircraft cockpits, HFE has since been effectively applied to the problem of human error in such diverse systems as nuclear power plants, NASA spacecraft, the process control industry, and "user friendly" software.
Today the health care industry is becoming aware of the costs of human error and is turning to HFE for answers. Just as early experimental psychologists went beyond the label of "pilot error" to explain how the design of cockpits led to air crashes, today’s HFE specialists are assisting the health care industry in identifying the causes of significant human errors in medicine and developing ways to eliminate or ameliorate them.
Regulators push for HFE in health care
As the positive effects of HFE in health care are recognized, government and other regulatory agencies are beginning to push for the use of HFE to reduce human error. The Association for the Advancement of Medical Instrumentation is currently revising its Human Factors Guidelines and Preferred Practices for the Design of Medical Devices (ANSI/AAMI HE-48-1993), and the International Electrotechnical Commission (IEC) is simultaneously revising IEC 60601-1, 3rd Edition: Human Factors Design Requirements.
The U.S. Food and Drug Administration has been especially busy in the area of HFE. In March 1997, it published Design Control Guidance for Medical Device Manufacturers. These design controls will ensure that good HFE processes are employed during product design and development. At the same time, a guidance document, Do It By Design, describes what the FDA intends when it states that HFE considerations must be taken into account when designing and validating devices.
The FDA also published Design Control Inspection Strategy, which guides field inspectors in aspects of HFE required for compliance with the new design control requirements. In addition, the FDA’s Center for Devices and Radiological Health forwarded a document titled Human Factors Points to Consider for IDE Devices to sponsors of approved investigational device exemptions (IDEs) to advise them of the need to pay attention to HFE as they conduct clinical studies to support development and validation of their new devices.
The new American Medical Association National Patient Safety Foundation (NPSF) will address the problem of medical error, including use error related to medical products as one of its primary foci. The NPSF is to be modeled after the Anesthesia Patient Safety Foundation, which is credited with reducing anesthesia patient mortality by a factor of 30 in the past 10 years.
Finally, the Joint Commission on Accreditation of Healthcare Organizations is seriously considering the causes and effects of human error in reviews and investigations.
Most human error in health care, as well as in other industries, is not due to bad intentions, poor training, improper personnel selection, or careless practice. Human error is generally not the "root cause" of an accident or incident; rather, it is usually one of a number of contributing factors. In many instances, error is either permitted to occur or actually induced by the design of the system, equipment, and procedures with which the person is working.
For example, a radiation source was left in a patient’s body during the course of a 1992 brachytherapy procedure. The tip of the probe had broken off, but the display indicated the "demand status" of the probe rather than the "response status." The technician thought that, given the indication of the display, the source had been removed. The system essentially lied to him.
In another brachytherapy case, a patient was seriously overexposed. The device required the technician to enter the date in order to calculate the delay of the source and establish the required exposure. Unfortunately, the device had been designed and built in Europe and used the European dating convention of DD/MM/YY. The technician, with all good intent, naturally used the American dating convention of MM/DD/YY. As a result, the calculations were greatly in error. Though it is easy to say the operator erred by inputting the date incorrectly, the real problem is that the system had induced the error by its design.
Incidents of syringe swaps are common in health care. Computer-based infusion pumps intended for home use also have been involved in errors, with some mistakes traced to the complex and arbitrary sequence of operations required to program the pump, different operating modes intended for different contexts, ambiguous alarms, and poor feedback on device state. All of those problems can be considered design-induced causes of user error.
So how does HFE apply to risk management in health care settings? An understanding of HFE and application of its principles to health care can help reduce errors by making your investigation more than just an exercise in placing blame. Even if your investigation of an accident reveals that an employee made a tragic human error, the principles of HFE will help you go a step further and determine why that human error was possible or even inevitable.
HFE is not intended simply to make people happier with the systems and machinery they use. Though HFE can indeed make systems and machinery more user-friendly, HFE enhances the total performance of the system by enhancing personnel performance, reducing errors and accidents, and enhancing personal safety. This will have the effect of enhancing worker satisfaction, but the total impact is much broader.
Though some HFE changes will seem obvious in retrospect don’t put the "on" and "off" buttons right next to each other, and don’t make them the same color HFE is not just common sense. If it was, there would be a lot less human error in the first place. HFE is a collection of tools and techniques for analyzing the human role in systems and the human use of equipment and procedures, and it is a process of finding the best way to combine human performance with the necessary machines, workspaces, environments, and procedures.
The appropriate application of HFE in health care should result in systems, equipment, and procedures that accommodate a wide range of users working under variable, often stressful conditions that are less prone to user error and that require less training and less sophisticated users.
Familiarity breeds success
HFE can be applied to a number of undertakings in health care. Within the health care facility, HFE can be of value in evaluating an existing system or one under consideration for purchase. The HFE evaluation can help identify potential usability problems and error-inducing aspects of design. HFE also can be used to ensure that the new equipment will integrate effectively into the existing operating environment without causing unforeseen difficulties or error potentials.
In other words, familiarity with HFE can help you spot problems with systems or equipment before you introduce them in your facility. Using a simplistic example again, you would be able to spot the potential problems with a machine that has identical "on" and "off" buttons next to each other. Without HFE, you might just expect your highly trained, well-intentioned employees to notice the difference and never confuse the buttons. With HFE, you might conclude that the equipment is poorly designed and represents an error-inducing addition to your facility.
HFE also can be used to examine procedures to identify and correct elements with the potential for inducing or permitting errors. In the event of an accident or sentinel event, HFE can be employed to go beyond the root cause of "human error" and identify those aspects of system and procedure design which contributed to, permitted, or increased the likelihood of the error. HFE also can recommend efficient and cost-effective means to reduce the likelihood of catastrophic results from similar human errors in the future.
[For more information, contact Daniel L. Welch, 4307 Harvard St., Silver Spring, MD 20906-4461. Telephone: (301) 946-2905. E-mail: DLWelch@ Carlow.com.]
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