Ergonomics

By Eric F. Shaver and Curt C. Braun

The right choices can improve safety and productivity

Health care organizations face increasing demands in the 21st century. Workforce shortages, rising financial concerns, and advances in medical technology are just a few of the challenges. Although medical technology has great potential, its implementation is often viewed as a mixed blessing. Medical technology that looked good during the initial sales presentation is likely to create as many problems as it solves.

Many of these problems originate from equipment that was not appropriately designed for the conditions in which it will be used or for the people who will use it. Equipment and technology must be incorporated into existing workflow and patient care practices.

Failing to adequately consider the design of equipment or technology, how it will work within existing systems and how physicians, nurses and other care specialists will interact with it can increase medical errors and threaten patient safety.

Even when medical technology undergoes an evaluation, the implementation is all too often associated with surprises that require changes in work methods and processes.

To capitalize on the potential of medical technology, it is incumbent on health care personnel to scrutinize needs, evaluate systems, assess impacts on patients and staff, establish work procedures, offer training and provide technical support and maintenance. Given the number of choices and the limited time and resources health care personnel can devote to such an endeavor, a way to facilitate the selection process is needed. One way makes use of methods from the field of human factors and ergonomics. 

Working proposition

Human factors and ergonomics is a unique scientific discipline that systematically applies the knowledge of human abilities and limitations to the design of systems with the goal of optimizing the interaction between people and other system elements to enhance safety, performance and satisfaction. In simpler terms, human factors and ergonomics focus on designing the world to better accommodate people. They are relevant anywhere people work with systems, whether the systems are social and/or technical in nature.

A health care organization is an example of a complex system that consists of many system elements, including people (e.g., patients, staff, etc.), technology (e.g., tools, machines, products, software, etc.), tasks, environments, organization (e.g., culture, policies, financial, etc.), industry, legal (e.g., regulations, enforcement, etc.) and political.

By taking a holistic approach to understanding the interactions between people and system elements, it is possible to identify the technological requirements that will best fulfill users’ needs, which in turn will improve quality and safety.

The people-centered systems approach used by human factors and ergonomics practitioners can give health care organizations a systematic method to use when purchasing and implementing medical technology.

It entails determining if the medical technology conforms to basic human factors and ergonomics principles and whether it will negatively influence the system into which it will be integrated.

An increasing number of health care organizations are turning to this methods as a means of facilitating the process used to specify, evaluate, procure and implement new technology.

Ideally, in the future, all medical technology will undergo some type of human factors and ergonomics methods prior to purchase and implementation in health care organizations.

In the business world, benefits are often judged by their return on investment (ROI). A common way to determine the benefit of a given initiative is by performing a cost-benefit analysis.

The results of such an analysis can guide where an organization can best invest their financial resources, thus maximizing their ROI. With regard to human factors and ergonomics methods, there is a growing body of literature that demonstrates a positive ROI for their implementation (see sidebar).

For example, in the book Usability Engineering, it was reported that a 6 percent budget investment on usability has provided returns of 200 percent to 500 percent. Specifically, for the health care industry, the potential benefits to patients and staff include:

Increased

• Patient and staff safety
• Productivity and work quality
• Staff satisfaction and acceptance
• Ease of learning and use (i.e., less training)

Decreased

• Number of adverse events
• Potential for introduction of new system hazards
• Need for modifications, “work- arounds” and/or shortcuts

Human factors and ergonomics practitioners use a variety of methods when evaluating, designing or procuring technology. Two human factors and ergonomics methods can be used to analyze potential state-of-the-art medical technology prior to procurement and implementation: Heuristic evaluations and usability testing.

These methods are directly applicable to health care organizations and can be performed either in-house or with the assistance of a human factors and ergonomics consultant. Ideally, a health care organization will use both techniques, given that they each have their own strengths and weaknesses.

Heuristic evaluations

Heuristic evaluations consist of evaluators using a list of human factors and ergonomics principles (Heuristics) to independently identify usability issues with a device.

With respect to health care organizations, the evaluators should be individuals who are familiar with the technology, the potential working conditions in which the technology will be implemented and have an understanding of human factors and ergonomics.

Heuristic evaluations have several strengths and weaknesses, including:

Strengths

• Easy to learn and use
• Requires minimal training
• Cost effective to implement

Weaknesses

• Does not discover missing functionality
• Relies on the knowledge and the experience of the evaluator

These evaluations consist of three steps: comparing the Heuristic list against the medical technology, identifying Heuristic violations and determining the severity of each violation.

For example, a set of 14 Heuristics, coined the Nielsen-Shneiderman Heuristics, were used by researchers in articles published in a 2003 issue of the Journal of Biomedical Informatics and a 2004 issue of the International Journal of Medical Informatics to evaluate the usability of medical infusion pumps.

The Nielsen-Shneiderman Heuristics were developed based on the combination of 10 user-interface design Heuristics proposed by Nielsen and the eight golden rules of interface design proposed by Shneiderman (see sidebar).

The procedure consists of evaluators independently rating each of the devices using the Nielsen-Shneiderman Heuristics and generating lists of violations.

The evaluators’ lists are aggregated for each device and redundant violations are removed.

The compiled lists are returned to the evaluators, where violations are assigned a severity rating using a five-point scale (0—not a usability problem, 1—cosmetic problem only, 2—minor usability problem, 3—major usability problem, 4—usability catastrophe), and an average severity rating is computed across the evaluators. The results from the Heuristic evaluation allow the number of devices to be narrowed down based on the lowest combined rating.

Heuristic evaluations are used for three reasons. First, they are used to identify potential usability issues that might arise from the medical technology itself or after its integration into the current system, which in turn, might lead to medical errors.

The literature indicates that one evaluator will find approximately 35 percent of the violations, while three to five evaluators will find approximately 60 percent to 70 percent.

Second, they are useful when comparing multiple devices. It allows the evaluators to “weed out” medical technology that has poor usability, thus saving the time and cost of performing subsequent usability tests.

Finally, the outcome of Heuristic evaluations can help guide training efforts by educating health care personnel about potential violations that routinely occur when using the medical technology, thereby decreasing the likelihood of medical errors.

Usability testing

Usability testing consists of having intended users (i.e., staff) perform routine tasks with the specific medical technology in a realistic setting. The steps required to complete a usability test include:

• Designing the test
• Performing a dry run and making modifications to the test design if necessary
• Recruiting users
• Conducting the test
• Analyzing the results
• Determining the appropriate action to take based on the test results.

Usability testing can capture objective and subjective outcome performance data. The former typically includes time to perform individual tasks, resolutions of tasks, and number and type of errors.

The latter includes user feedback regarding strengths and weaknesses of the medical technology, perceived ease of use and observations made by the tester.

As with Heuristic evaluations, usability testing can help guide user training by covering violations that routinely occur when using the medical technology.

An article published in a 1992 issue of Human Factors, along with the book Usability Engineering, has shown that testing with five users will typically find approximately 80 percent of the usability problems.

Usability testing has several strengths and weaknesses, including:

Strengths

• A small number of test participants are needed to identify most problems
• Identifies the severity of usability problems
• Detects problems not identified by Heuristic evaluations

 Weaknesses

• Can be time consuming and costly to perform
• Requires testers that are knowledgeable with the method

In the end

The people-centered systems approach of human factors and ergonomics can give health care organizations a systematic method of purchasing and implementing medical technology. Health care organizations should incorporate both Heuristic evaluations and usability testing to identify potential problems with the introduction of new medical technology into an existing system.

Heuristic evaluations are useful for identifying potential medical technology usability issues that might occur from the technology itself or after its integration in the current system. However, Heuristic evaluations cannot capture all the potential usability issues for new medical technology or the level of staff acceptance and increased work efficiency. 

Thus, it is also necessary to conduct usability testing with health care personnel. While both methods have their place, when used in tandem, they can have the greatest impact and success. These methods also help determine whether the medical technology effectively serves the goals of organizations (e.g., decreased medical errors). Finally, human factors and ergonomics methods are designed to help health care organizations maximize their ROI by increasing the positive and reducing the negative impact that new medical technology can create.

Eric F. Shaver, Ph.D., is a senior consultant, and Curt C. Braun, Ph.D., is the president, CEO and founder of Benchmark Research & Safety Inc., Moscow, Idaho. Benchmark provides consulting and services for a variety of areas, including human factors and ergonomics, usability, safety and training.

This article first appeared in the September 2008 issue of Materials Management in Health Care.

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