Imagine that you are an experienced nurse starting a new job at a large teaching hospital. You’ve been assigned to a cardiac-care unit where your first patient is a 65-year-old male with acute hypertension (high blood pressure). The charge nurse asks you to set up and begin an intravenous infusion for the patient using a four-channel pump that you’ve never operated before.Fortunately, the comparatively advanced device is intuitive to use. The device’s large computer display explains exactly what to do at every step, from hanging the IV solution bag to inserting the IV tube into the pumping mechanism to programming a flow rate. After the pump checks that the programmed dosage is safe, it directs the user to start the infusion by pressing the big green button that dominates the front panel.Potential delay or compromise to patient care averted! Instead of struggling to understand how to set up and run the unfamiliar pump, you could follow the instructions and draw upon your existing knowledge and skills to operate it correctly the first time. Wouldn’t it be nice if all user–device interactions went this smoothly?Regrettably, many user-device interactions do not proceed this smoothly. Rather, caregivers frequently encounter obstacles trying to use an unfamiliar device. The device may offer little guidance on its proper operational sequence, leaving the user guessing what to do next. It may require the user to look up and enter a cryptic numerical code to start a function, thereby opening the door to confusion and user error. Or the device may provide little feedback to judge whether it is working properly.Caregivers, many of whom consider themselves “can do” individuals, overcome such obstacles by seeking guidance from experienced colleagues or by simply spending precious time figuring things out. Naturally, most caregivers prefer devices that are easy to use from the start, especially considering the large number of devices they encounter in their work.The key for medical device developers is to fulfill their customers’ need and desire for initial ease of use (i.e., intuitiveness) without compromising operational efficiency (i.e., task speed). It’s a balancing act that requires developers to take a holistic view of the user experience, which may begin with in-service training or self-discovery and span a decade of daily use.Limitations of TrainingDevelopers often cite training, particularly in-servicing, as the cure-all for products that are difficult to learn to use. The average in-service session lasts no more than an hour and may include a dozen or more people. Some trainers may wish to provide more information one-on-one, but caregivers usually do not have sufficient time to devote to in-depth training.
Criticare Systems’s 504 DX portable pulse oximeter employs large, well-spaced membrane keys.
Typically, a manufacturer’s representative teaches the in-service sessions, covering the basic operational concepts and demonstrating the essential tasks. Many hospitals take a “train the trainer” approach that calls for key staff, such as nurse educators, to receive training from the manufacturer’s representative, then pass the lessons along to other staff. Caregivers generally much prefer hands-on training to reading and following instructions in a user manual.However, despite the popularity and presumed effectiveness of in-service training, many first encounters between caregivers and medical devices actually occur at the point of care, such as the patient’s bedside. A caregiver may have missed the training because she or he was busy with a patient or was off duty. In some cases, caregivers “float” from another unit that does not use the particular device and, therefore, have not received training. Perhaps the caregiver comes from a temporary nurse agency that has supplied RNs to address a staffing shortage. Or, it may be a caregiver’s first day on the job, as described earlier, presenting no prior opportunity for training.Accordingly, it is wrong to assume that all staff will receive formal training before they use a particular medical product, despite the movement to require caregivers to complete training exercises before they are authorized to use a device. Restrictions on device use are simply not the norm at this time. So, the burden remains on manufacturers to design products that enable users to easily understand a device for themselves—and quickly—before a patient suffers any harm.Intuitive Design: Caregiver’s PerspectiveHuman factors textbooks offer extensive advice on how to design intuitive user interfaces. However, caregivers are also a good source of guidance. The following recommendations have been distilled from interviews with several nurses working in general medical and critical-care environments. Notably, many of the design characteristics that enhance intuitiveness also tend to reduce the potential for user error and increase product appeal.Provide Extensive Prompts. Nurses want devices to lead them through a clear and consistent series of actions to accomplish a task, almost as if a human guide were leading them. They view prompting (i.e., a series of short, context-sensitive instructions) as the surest way to avoid skipping a critical step. They accept that prompting may increase the time required to complete a task, but feel that extensive prompting can speed up procedures by reducing the need to seek help. They also see prompts as a means for new users to teach themselves to use a device in a fail-safe manner.One nurse commented that she attended an in-service session on how to use an epidural pump, but then did not see it for another few months, leaving her time to forget her training. She felt that step-by-step prompting would have been her savior if she were pressed to use the pump with little notice. She noted that nurses are prone to take any shortcuts that save time, but deep down prefer to follow methodical procedures that prevent errors.Another nurse commented, “Why keep steps 1 – 2 – 3 and 4 a secret? Print them right on the product.” She was less concerned with making a medical device look too simplistic than with ensuring that every person operated the device correctly. So, while literally labeling a product with the numerals 1 – 2 – 3 and 4 may not always be a viable solution, the underlying intent seems valid: design the user interface to accentuate the proper operational sequence. One nurse insisted that a device should not only tell users when they do something wrong, but should also tell them how to correct their mistake. She welcomed the use of voice output as an intuitive means for appropriate devices, such as defibrillators, to communicate with caregivers.Use Prominent Labels. Nurses applaud the use of prominent labels to conspicuously indicate a device’s purpose and proper operation. One nurse offered the example of labeling defibrillator pads with the words Front and Back in large black letters as a good way to direct users to apply them correctly. She explained that first responders, such as members of a Code team, have little time to figure things out in a crisis. They perform tasks by rote rather than pausing to identify and analyze their options. So, they are better off when a device spells out the operational basics in an almost exaggerated manner.Commit to a Single, Optimized Configuration. Contrary to the call for customization, nurses considered device configurability to be a problem. In their view, enabling devices used within the same institution to assume various configurations compromises a nurse’s ability to master their operation. Consequently, experienced nurses may encounter new configurations that take time to decipher. Many would sacrifice flexibility for the sake of configuration stability, noting that stability enables the experienced nurse to provide expert support to new users.Prevent Users from Turning Off Critical Alarms. Nurses recognize that they may give device manufacturers conflicting guidance regarding alarms. They despise nuisance alarms that create more work. However, they recognize the underlying benefit of alarm systems associated with critical therapeutic and monitoring devices. Therefore, they advise manufacturers to prevent users from turning off any critical alarms, presuming that users can silence alarms for an appropriate amount of time.Provide Large Displays. Large displays have obvious benefits. They provide enough space to utilize large graphics, text, and numbers, making the information readable from a distance. Designers can also use large displays to emphasize critical procedures, which helps both new and experienced users focus on the most important information. Large displays also provide room for prompts.One nurse lamented that manufacturers seem to design their products for people in their 20s who have better than 20/20 vision and who will view displays in ideal lighting conditions. Noting that the average age of nurses is in the mid-40s, she advised manufacturers to oversize their displays, labels, and other printed materials so they are legible to people who have reduced visual acuity. Provide On-Line Help. Nurses like an embedded on-line help system, as long as the manufacturer invests enough resources to make it truly helpful. One nurse described on-line help systems as a time-saver. She noted that she could direct new nurses to check the on-line help if they encounter operational problems, thereby reducing demands on her time.Another nurse considered on-line help superior to quick-reference cards because cards become worn and outdated, whereas on-line help contains more information and can provide context-sensitive assistance. She also commented that nurses just out of school are quite comfortable with computers and expect a sophisticated device to incorporate on-line help, just as they expect contemporary software applications to include one.Another nurse insisted that smart devices, such as those that incorporate an on-line help system, should tell new users what they need to know about operating the device in three minutes or less. She explained that nurses in her large hospital rarely have time to attend an hour-long training session. She added that so much equipment is being “rolled out” that she would be attending such sessions all the time rather than attending to her patients.Provide Large Controls. One nurse observed, “I’ve yet to see a device with buttons that were too big.” This comment underscores the view held by several nurses that large controls make a device easier to use and, conversely, that small controls make a device harder to use. The association between large controls and ease of use may be part perception, but one can understand the preference for controls that provide a good visual target as well as a firm grip. Shape and color coding can make controls even more intuitive. Touch screen–based controls, such as those found on some patient monitors, can also make a device easier to use, presuming that the touch targets are not crowded together and provide effective actuation feedback by means of visual effects and sounds.Be Consistent. Several nurses recommended that manufacturers standardize their controls and graphical symbols. One nurse noted that people could step into virtually any rental car and drive away because the placement and operation of the primary controls are relatively consistent. She challenged medical device manufacturers to achieve a similar degree of design consistency so that caregivers can easily switch from one medical device to another.One nurse advised manufacturers to make all of the necessary connections obvious, half-seriously suggesting that some manufacturers now go so far as to hide connection ports from the user. She also recommended using shape and color coding to the maximum extent possible so that making the proper connections is a simple matter of matching up similar looking components.Automate Appropriate Functions. Nurses welcome automation as long as they can remain “in the loop” in terms of understanding a patient’s condition so that they are prepared to respond effectively to emergencies, including those involving a device failure. For example, nurses feel no strong need to calibrate a device or run a maintenance check if the device can be engineered to perform these functions automatically. Such automation makes devices easier to learn because there is simply less to learn.Avoid Minor Changes. Nurses get frustrated by minor, incremental changes to medical devices that contradict the expectations they have developed using earlier-generation products. They recommend that manufacturers stick to one method of operation, rather than introduce a slightly different scheme of operation, until they are ready to launch an entirely new iteration of the device. Minor changes can actually be more confusing than wholesale changes.Enable Users to Practice Tasks. Nurses welcome medical devices that incorporate a simulation mode and the accessories necessary to practice using them. Such devices enable users to gain proficiency with a device before using it on a patient. However, devices need protections in place to prevent users from confusing simulated performance with actual performance.Enable Users to Perform Checks. Nurses also welcome the increased computing power found in many devices that makes it possible to check user settings, such as a programmed infusion rate. Such power enables them to ensure that the settings fall within the boundaries of normal use established by the manufacturer or healthcare institution. That way, if their inputs fall out of the normal range, the device can alert them to the potential hazard, such as a morphine overdose.Make Important Features and Information Prominent. Nurses recognize that some controls and displays are used more frequently or urgently than others and that some controls and displays perform especially critical functions. They feel that the important controls and displays should grab the user’s attention. This may be accomplished by making them larger, segregating them from others, or coding them in a conspicuous manner, such as giving them a special shape or color.Hold the Extras. Manufacturers feel compelled by market forces to include extra features in their products because procurement processes tend to reward feature-filled products that appear to offer greater value. However, nurses view most extra features as excess baggage that gets in the way of simple operation. One nurse commented, “Our patient monitors have lots of advanced features. I have no idea what they do.”But, is the answer to eliminate the extras altogether? Perhaps, depending on whether the extras are important to a small percentage of potential users or practically nobody. For example, one nurse cited the dose calculator built into some infusion pumps as an extra that is useful to a small percentage—perhaps 20 percent—of all users. But other extras may be useful to only a handful of people and not worth keeping. Another solution is to isolate the extra features by placing them behind a panel or in a software menu. However, this solution is antithetical to human factors guidelines, such as creating logical functional groupings and providing easy access to functions. Therefore, the best approach is to scrutinize every feature in terms of its true value and to purge those that increase complexity while adding little benefit.ConclusionThe medical care environment rivals consumer electronic stores, such as Best Buy and Circuit City, as a technology haven. Within critical-care environments, one finds blood gas analyzers, defibrillators, electrocardiographs, electronic thermometers, infusion pumps, noninvasive blood pressure monitors, patient monitors, patient warmers, diagnostic spirometers, and many other specialized devices. For nurses and other caregivers, these devices present a lot of technology to master, so it is no wonder they gravitate toward intuitive designs.In a perfect world, there would be enough time to learn how to use all the features built into all of the medical devices. However, in the real world, most caregivers worry about learning the basics and utilizing the special features only when necessary and, often, only as time permits. This makes intuitiveness a critical design feature and a great opportunity for innovation, even if the innovation is the removal of an extraneous feature.
Michael Wiklund is a human factors consultant in Concord, MA. He chairs the Medical Section of the Industrial Designers Society of America. Copyright ©2005 Chinese Medical Device Manufacturer