Providers need safety and efficacy in medical products and equipment.
Add usability, and you’re that much closer to a sale.
Pharmaceutical labels and packaging that look so much like others, patients get the wrong medication. An insulin pump that’s difficult to program or calibrate. Blood pressure tubing that is erroneously connected to an IV catheter, resulting in a fatal air embolus. These things happen, usually chalked up to “medical error.” But who’s responsible? The nurse? Pharmacist? Respiratory therapist? How about the manufacturer?
The fact is, manufacturers of medical devices and equipment jump through hoops with the FDA to demonstrate their products are designed with “human factors” in mind. It’s called “human factors engineering.” Basically, it refers to the ease of use of a medical product, device or piece of equipment. It’s an important point, because if it’s not easy to use, someone’s going to get hurt, either a patient or a healthcare worker. For that reason, human factors engineering – though an unlikely tagline – can be an important selling tool for medical salespeople.
Warm and fuzzies?
Making something usable isn’t about warm-and-fuzzy add-ons. Rather, usability is designed into the device. In fact, the U.S. Food and Drug Administration has a definition for human factors engineering and usability engineering: “The application of knowledge about human behavior, abilities, limitations, and other characteristics of medical device users to the design of medical devices including mechanical- and software-driven user interfaces, systems, tasks, user documentation, and user training to enhance and demonstrate safe and effective use.”
Patrice Tremoulet, PhD, human factors scientist for ECRI, says she would add the word “comfortable” between “safe” and “effective.” “Clinical users (and patients) need to be able to use things not only safely and effectively but also comfortably, otherwise you set them up for either repetitive stress injuries or inadvertent misuse during times of fatigue.”
“No product development occurs where the goal isn’t ease of use,” says Mary Beth Privitera, PhD, FIDSA, professor of biomedical engineering at the University of Cincinnati and co-chair of the Association for the Advancement of Medical Instrumentation (AAMI) Human Engineering Committee. “But sometimes it gets lost.” Often that’s because the people designing medical devices aren’t the ones practicing medicine.
The FDA and industry groups feel a special urgency today to prevent that from happening. “Use errors caused by inadequate medical device usability have become an increasing cause for concern,” write the authors of the international standard IEC 62366, which specifies how manufacturers should analyze, specify, develop and evaluate the usability of a medical device as it relates to safety. “Many of the medical devices developed without applying a usability engineering (human factors engineering) process are non-intuitive, difficult to learn and difficult to use. As healthcare evolves, less skilled users, including patients themselves, are now using medical devices, and medical devices are becoming more complicated.”
Three tenets
Privitera points to three fundamental tenets of human factors engineering. “First, there must be a clear definition of who the user will be, taking into consideration demographics, physical characteristics, language, education level, etc. And because most products are made for the global market, cultural norms have to be considered too.”
Second, designers must try to understand the use environment and its variability. “A device may start in the OR, then follow the patient to the PACU, then to the floor, and perhaps even home.” A physician may initially place the device on or in the patient, but a nurse, respiratory therapist or other clinician may be responsible for maintaining it. There is also the question of how the provider/s can review historical data, such as that from monitoring devices.
And third, “you have to consider the use environment and use scenario,” she says. “So, if I know the user, the use environment and the use scenario, I – as the manufacturer – can ask questions like, ‘How can I make this better by design?’”
User interface
A term often associated with computers – user interface – is key to human factors engineering. The FDA defines it as “all points of interaction between the user and the device.” It comes into play when the user sets up the device (e.g., unpacking, setting up, calibrating), uses it, or performs maintenance on it (e.g., cleaning, replacing a battery, repairing parts). User interface involves:
- The size and shape of the device (particularly a concern for hand-held and wearable devices).
- Elements that provide information to the user, such as indicator lights, displays, auditory and visual alarms.
- Graphic user interfaces of device software systems.
- Overall user-system interaction, including how, when, and in what form information (i.e., feedback) is provided to the user.
- Components that the operator connects, positions, configures or manipulates.
- Hardware components the user handles to control device operation, such as switches, buttons and knobs.
- Components or accessories that are applied or connected to the patient.
- Packaging and labeling, including operating instructions, training materials, and other materials.
The FDA says that physical, mental and emotional characteristics of users must also be considered by product manufacturers. They include:
- Physical size, strength, and stamina.
- Physical dexterity, flexibility, and coordination.
- Sensory abilities (i.e., vision, hearing, tactile sensitivity).
- Cognitive abilities, including memory.
- Literacy and language skills.
- General health status.
- Mental and emotional state.
- Level of education and health literacy relative to the medical condition involved.
- General knowledge of similar types of devices.
- Knowledge of and experience with the particular device.
- Ability to learn and adapt to a new device.
- Willingness and motivation to learn to use a new device.
“The healthcare workforce is large and very diverse,” says Tremoulet. “So it’s important to test new devices and equipment not only with users who are representative of intended users, but also others, including patients and caregivers. Whenever possible, principles of universal design – making things that everyone can use – should be applied.”
The environments in which the medical device or equipment might be used – including clinical environments, non-clinical environments, community settings or moving vehicles – are also part of human factors engineering. Questions to be considered include:
- Lighting level: Is it low or high, making it hard to see device displays or controls?
- Noise level: Will users have difficulty hearing device operation feedback or audible alerts and alarms, or distinguishing one alarm from another?
- Does the room contain multiple models of the same device, component or accessory, making it difficult to identify and select the correct one?
- Will the room be full of equipment or clutter or busy with people and activities, making it difficult to maneuver and providing distractions that could confuse or overwhelm the device user?
- Will the device be used in a moving vehicle, subjecting it and the user to jostling and vibration that could make it difficult to read a display or perform fine motor movements?
Progress
“Today, manufacturers and providers realize that improving usability – not just of devices and equipment but also of workflow and workplace layout – is more likely to have a sustained significant positive impact on patient safety than training, incentives, establishing organizational goals or creating mandates,” says Tremoulet.
Says Privitera, “The fact of the matter is, we’ve realized we can’t develop safe medical devices without considering usability. Ten years ago, we were just recognizing the need to take into account human factors. The conversation has changed: Now it’s about what constitutes good human factors engineering.”
The expectations from a regulatory standpoint have also increased, she says. The FDA’s Human Factors
Premarket Evaluation Team serves as consultants on the multi-disciplinary review team of various premarket submissions in the agency’s Center for Devices and Radiological Health (CDRH) and other centers. The team is responsible for evaluating use-related risk analyses, and human factors/usability information and validation study data included in the submission. The recommendations are reviewed and incorporated in FDA letters to the device manufacturer.
“When a medical device is easy to use, it means the manufacturer has taken the time to learn about the customer, the use environment, the context of use, and then put features in that make sense,” says Privitera. “We’ve really advanced.”
Providers themselves can play a role in advancing the craft of human factors engineering, says Tremoulet. “They can provide candid feedback, both positive and negative, to manufacturers about their existing products. Manufacturers want their products to be used safely and effectively, and even comfortably, but they don’t always have good access to representative end users. Concrete feedback, which can be anonymous, is extremely valuable to them.
Within healthcare organizations, encouraging management to obtain samples that can be tested in clinical environments or in simulation before purchasing large quantities, is also helpful. “Any usability issues uncovered should be carefully considered by management/purchasing organizations and shared with manufacturers.”
Sidebar:
Why is Human Factor Engineering important to medical devices?
For medical devices, the most important goal of the human factors/usability engineering process is to minimize use-related hazards and risks and then confirm that these efforts were successful and users can use the device safely and effectively, according to the FDA.
Specific beneficial outcomes of applying human factors/usability engineering to medical devices include:
- Easier-to-use devices,
- Safer connections between device components and accessories (e.g., power cords, leads, tubing, cartridges),
- Easier-to-read controls and displays,
- Better user understanding of the device’s status and operation,
- Better user understanding of a patient’s current medical condition,
- More effective alarm signals,
- Easier device maintenance and repair,
- Reduced user reliance on user manuals,
- Reduced need for user training and retraining,
- Reduced risk of use error,
- Reduced risk of adverse events, and
- Reduced risk of product recalls.