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Blending Form and Function: Good Design Starts with Usability


Posted by mddiadmin on April 1, 2004

Originally Published MDDI April 2004

Cover Story

Sherrie Conroy

Good design can often mean the difference between the success or failure of a product. Defining good design is often subjective, but customers know intuitively what works and what doesn't. The MDEA jurors noted that some of the winning products excelled particularly in their design, providing a significant improvement over currently available products.

“Industrial design encompasses the creation of a product's physical form and its points of user interaction,” said juror Michael E. Wiklund, vice president of human factors research and design for the American Institutes for Research (Concord, MA). “Invest in industrial design, and you get a product that satisfies the intended users on several levels, including intuitiveness, effectiveness, efficiency, and appeal.”

He stressed that medical devices should have appeal in addition to satisfying a functional requirement. He explained that some clinicians spend several hours a day operating medical devices, so devices need to be “a glove fit” with the task requirements and the users' preferences. Products that are easy to use make people more effective at their jobs. “Products that are hard to use are the source of user complaints. They run up the cost of training and induce user errors that can place patients at risk and cause equipment damage and material waste,” Wiklund added.

The jurors noted that although some design changes are incremental improvements to existing devices, the improvements are such that they offer a real and tangible benefit to the clinician or patient. “Many products were beautifully designed but not very innovative, and many products were very innovative but poorly designed. We tried to choose for awards the few that fell into both categories,” said Stephen B. Wilcox, PhD, founder and principal of Design Science Consulting Inc. (Philadelphia).

As they identified products deemed superior in design, the term ease of use came up often. It emerged as a core element of what determined good design. “Ease of use is the quintessential aspect of how I would evaluate a product's excellence,” said juror Tor Alden, principal at HS Design Inc. (Gladstone, NJ). “If it's not easy to use,” he added, “no matter how valuable it may be to doctor, nurse, or patient, it has not reached award-winning status.” 

He noted, however, that ease of use is not black and white. “Depending on the class of instrument or the complexity of the task, successful ‘ease of use' products may require training.” When usability is done right, Alden said, the user can adapt to the process and retain the process steps quickly. He stressed that usability is also tied heavily to the intuitiveness of a device. “Color-coded attachment points, common interfaces among product lines, icons, and cheat sheets all come into play,” he explained.

“I think that it's fair to say that ease of use was a key criterion that we required for design awards. The only exception was if the product was so new and revolutionary that we gave it some slack vis-à-vis ease of use,” said Wilcox.

“But,” Wiklund added, “you would expect the manufacturer to follow right away with an version optimized for usability.” Wiklund also noted that clinicians do not have time to waste using products that increase their mental and physical workload. “Accordingly, I view ease of use as an essential characteristic of an award-winning product.”

“When talking about perception, look and feel and personality are words often used,” Alden said. “We believe all products have a personality, similar to the way people do. Some are friendly, some are approachable, some are easy to deal with, and some require more energy than they are worth.” In medical design, approachability, intuitiveness, ease of use, and strategic value are the most critical aspects, he explained. Products that exhibit all these qualities will create superior demands by the user and thereby stimulate sales and create brand loyalty. “Design excellence, in my opinion, must have all these components,” he stressed. The winning products described in the sections below go far toward satisfying those criteria.

Audicor Cardiograph Expansion System

The Audicor cardiograph expansion system, manufactured by Inovise Medical Inc. (Newberg, OR), provides primary-care and emergency medicine physicans with automated detection and reporting of heart sounds and ECG information to aid in timely diagnosis of congestive heart failure, acute coronary syndrome, myocardial infarction, and left ventricular hypertrophy. 

The Audicor cardiograph expansion system, manufactured by Inovise Medical Inc. (Newberg, OR), provides primary-care and emergency medicine physicans with automated detection and reporting of heart sounds and ECG information. It is designed to aid in timely diagnosis of congestive heart failure (CHF), acute coronary syndrome (ACS), myocardial infarction, and left ventricular hypertrophy. 

“It's really a clever little device,” said juror Wilcox. “You replace two of the leads of an ECG and it plugs right into the system. It puts an additional line on the ECG, which provides heart sounds.”

One of the goals for the Audicor product was that it made use of the same patient preparation and hookup procedures as a normal 12-lead ECG, according to Sue Hart, director of development for Inovise Medical. “In order to do this, it meant that our sound sensors had to double as normal ECG electrodes,” she said. “Our design of the sensor, in fact, handles this through two of the additional ECG channels that the targeted electrocardiographs provide.”

Hart pointed out that not all electrocardiographs provide more than 12 ECG channels. Only certain models used for pediatric hookups and research have the extra channels. “If we had not combined ECG electrode capability into the Audicor sensors, the ECG technician would have had to apply two standard electrodes as well as two sensors in the V3 and V4 positions,” she added.

Wilcox noted that the device was particularly well suited for nonspecialists. “It has a built-in microprocessor that uses algorithms to process the ECG for noncardiologists,” he said. “For example, those in the ER might not be able to read an ECG in the sophisticated manner a cardiologist would.”

Hart said the mounting options were key to the design. Because the unit runs on four different cardiograph models, each with different form factors, the company designed four separate mounting schemes. “The challenge here was to minimize kludge as much as possible for each unit, while also accommodating easy use,” said Hart. “Our goal was to be able to upgrade existing carts at user sites as well, so each design was constrained to attributes of those carts.”

Emergency departments and primary care physician were seen as the natural targets for patients with early or symptomatic indications of ACS and CHF. “To best provide diagnostic value for these heart conditions, our product had to be designed with its users and user environments in mind.”

Hart said that most U.S. emergency departments use the four cardiographs that the Audicor CE runs with. To preserve the existing features of these cardiographs, she said, “it meant that one of the design goals had to be minimal interference with normal, intended cardiograph use.”

“This is a new technology that improves clinical care in a very simple and clever way,” commented Wilcox.

Dermabond Topical Adhesive ProPen XL

The Dermabond topical adhesive ProPen XL, manufactured by Closure Medical Corp. (Raleigh, NC) is a disposable, sterile, single-use delivery system for Dermabond topical skin adhesive (Ethicon Inc.). The applicator system is designed for precision application of liquid adhesive technology, which can replace sutures and staples in surgical procedures. 

The Dermabond topical adhesive ProPen XL, manufactured by Closure Medical Corp. (Raleigh, NC) is an applicator system for topical adhesive. Specifically, it is a disposable, sterile, single-use delivery system for Dermabond topical skin adhesive (Ethicon Inc.) and is designed for precision application of the liquid adhesive technology, which can replace sutures and staples in surgical procedures.
“One of the key design goals [of the ProPen XL] was to make the device intuitive to the user, not requiring any additional training or extensive instructions, while maintaining a high level of product performance,” said Bill Cotter, vice president of operations for Closure Medical.

“Through the use of rapid prototyping methods, we were able to quickly modify and adapt early design concepts that then were taken directly to clinicians for evaluation,” Cotter said. “Extensive preference studies, surgeon panels, and one-on-one interviews with physicians in addition to direct observation of surgical procedures by the development team were instrumental in ensuring that user needs were addressed from the very early stages of product development.”

Prior to commercialization, he added, design validations were conducted with the clinician base to verify that the final design met or exceeded their needs.

The jurors found the new package for delivering surgical adhesive very innovative. The glue is packaged in a glass vial, and a 180Þ turn activates a plunger that dispenses the adhesive. “The design is unique in its approach and fairly ergonomic and disposable,” said juror Yadin David, PhD, director of the biomedical engineering and television services department at Texas Children's Hospital (Houston). “It eliminates the need to manually mix in the operating room. It is very easy to use to replace sutures in skin closure, and you know the glue is being discharged,” he added.

“The Dermabond topical adhesive ProPen XL shows a good example of proper usability,” said Alden. He noted that the two-part surgical glue had previously been mixed at the point of application using a series of steps. “They reduced the steps to a simple twist of an applicator breaking a glass vial,” he said. “Pressing the integrated plunger dispenses the glue through a felt applicator, similar to a pen. Simplistic as this may seem, the designers spent considerable time getting to this level of ease of use.

“The ergonomic advantages of this product are self-evident,” said Wiklund. “One applies the topical adhesive with the same intuitiveness as drawing on a tablet. By design, the product reduces the user's workload.” He noted that with this device, no mixing is required, and cleanup is a simple matter of disposing of the applicator. “The adhesive product itself isn't new, but it's packaged in way that really improves ease of use,” said Wilcox.

System 100 Fluid Removal System

The System 100 fluid removal system, manufactured by CHF Solutions Inc. (Brooklyn Park, MN), removes up to 4 L of fluid over 8 hours from patients with fluid overload. It consists of a microprocessor-controlled console, disposable extra-
corporeal blood circuit, and venous access catheters. 

The System 100 fluid removal system, manufactured by CHF Solutions Inc. (Brooklyn Park, MN) removes up to 4 L of fluid over 8 hours from patients with fluid overload. It consists of a microprocessor-controlled console, disposable extracorporeal blood circuit, and venous access catheters.

“We liked it because it has a combination of mechanical, electrical, software algorithm, packaging, and biomaterials in a nice, easy-to-use system,” said David. “It removes fluid from the vascular system of people that have congestive heart failure. Each system has a key with software coded into it, and part of the application is to use the key to identify the specific system, flow rate, pressure. It is intuitive.” 

“The biggest step we took in the design of this product was to really understand who the customer was and what the customer wanted,” said John O'Mahony, vice president of R&D for CHF Solutions. “This cannot be done from behind a desk and can only come from real-world interaction.”

A company founder, Howard Levin, MD, is both a cardiologist and an engineer. “Being a cardiologist, he realized that even though the therapy may be prescribed by the cardiologist, it would be implemented by a nurse,” said O'Mahony.

On most medical device design projects, he said, the engineering department does not directly interact with the customer, making it difficult to get feedback when critical decisions are being made. But on the System 100 project, all of the engineers participated in clinical trials and interfaced with customers. “Engineers were always just a telephone call or walk across the street to getting customer feedback,” he said.

Product introductions can fail if nurses take a dislike to the product, noted O'Mahony. This occurs if a product is not intuitive to use, uses unnecessary alarms, or takes too much time to set up and use for the perceived benefit, he said. “From the very start of the project we believed that nurses could be our biggest advocates and that we needed to satisfy their needs if we were to design a successful product.”

He explained that a fundamental difference exists between the ways a nurse and an engineer respond to a device alarming. When a nurse hears an alarm he or she first looks to see whether the patient and setup are still OK. If the patient is OK, the nurse generally clears the alarm to see if it reoccurs. By contrast, he said, an engineer looks at the device to determine the cause of the alarm. These different perspectives on technology must be appreciated if a product design is going to be successful, O'Mahony said. “We took every step possible to ensure that our device would alarm only when necessary.”

O'Mahony said the company used an iterative design approach, noting the importance of having potential users give feedback as soon as possible. “We solicited feedback on how to make the user interface and alarm systems more user friendly and tried to tailor alarm messages to the nurse and not to the engineer. We ran a trial in Romania within nine months of starting the project, which led us to further simplify the device before performing [a trial] here in the United States.” He said this iterative approach helped validate user requirements and implementation.

“The display is very clear, the graphical user interface is very clear, and the landscape is divided: function on right, order on left, input in middle,” noted David. “This is innovative for CHF patients. Nothing else does this. The interface is very solid, and the manufacturing is good.” 

The system's engineering requirements were generated from true user requirements. On many projects, said O'Mahony, the engineering team is left trying to fight science by being asked to achieve some unrealistic sensor or actuator accuracies. “Avoiding this pitfall gave the team more time to focus on the true requirements,” he said.

“The System 100 fluid removal system, to me, was one of the best examples of great ease of use or usability,” noted Alden. “I was able to put the disposables and tubing in place within minutes without any instructions.” Alden added that although the instrument is very complicated, the jurors required no training to set it up. Some of the factors contributing to its simplicity, he said, were its use of color coding and of one-way attachment points.

“Ease of use as a design element saves the manufacturer and the buyer money,” said Alden. It provides for fewer service calls, less training, and more productivity. “The system is a classic example of the benefits of applying usability in the design process.” 

“This system has a lot going for it in terms of hardware design,” said Wiklund. “It has many features designed to make tasks proceed smoothly. The device's form looks refined and places the display and controls in a physically and visually accessible location.”

Unlike a lot of medical devices, he added, the display is large enough to communicate a good amount of information on a single screen, rather than requiring the user to page through many screens. The control panel appears easy to clean with the wipe of a wet cloth. “The controls themselves appear large enough to press without concern for selecting the wrong one. The Run and Stop keys are color coded to draw attention. No doubt, a clinician would be able to find the Stop key quickly in an emergency,” he said.“Aesthetically, the device's blue color gives the product character while still harmonizing with the use environment.”

CT Exprés Advanced Contrast Media Delivery System

The CT Exprés advanced contrast media delivery system, manufactured by Swiss Medical Care, SA (Lausanne, Switzerland), handles contrast media used for computed tomography. It provides multidosing and programmable saline flushing for applications in both the public and private imaging markets.

The CT Exprés advanced contrast media delivery system, manufactured by Swiss Medical Care, SA (Lausanne, Switzerland), was designed to handle contrast media used for computed tomography. It provides multidosing and programmable saline flushing for applications in both the public and private imaging markets. 

“This device answers a problem a lot of people have,” said juror Dale Bevington, cofounder of Product Innovation Partners (London). “The achievement is a large-scale bottle to hold the dyes with a disposable area. You can run the device all day long without having to flush it.” 

“To prove a high level of clinical hygiene, the CT Exprés was tested under worst-case conditions and with viruses—instead of having only bacteria—used for simulating the risk in daily use,” explained Larry Minix, CEO of Swiss Medical Care. “Knowing that some customers try to reuse disposable products, the system was designed to eliminate the possibility of doing so. The safety disposables are designed so that reuse is excluded. Software routines control the proper use of disposables.”

Minix said that the time-consuming manual handling of preparing an injection (e.g., filling disposable syringes) is no longer an issue with the CT Exprés. “The radiographer can focus more on the patient and, by saving time, the patient throughput can be increased. The waste of contrast can be reduced because the contrast is directly injected from the bottle through the safety disposables,” said Minix.
Minix said that previous attempts by others to develop peristaltic systems have been unsuccessful because they were not able to achieve guaranteed parameters such as flow rates.

“The device is a patient-by-patient disposable, so there is no problem with a syringe,” noted Bevington. “It's a good idea for sorting out a real problem. It stops air before injection stops, and it has an incredibly fast injector.” The real improvement, he said, is that it is “fundamentally different from a syringe” for dispensing dyes for scans.

“This solves an old problem in a new way by getting rid of injector syringes,” said Wilcox. “It allows for the contrast container to be mounted directly to the machine. To my knowledge, this hasn't been done before.”

Diego Powered Dissector

The Diego powered dissector, manufactured by Gyrus ENT LLC (Bartlett, TN) is a powered tissue dissector for ear, nose, and throat (ENT) surgery. It is used with the patient under general anesthetic. The dissector incorporates an electrically powered handpiece and single-use, disposable cutting blades and burrs. 

The Diego powered dissector, manufactured by Gyrus ENT LLC (Bartlett, TN) is a powered tissue dissector for ear, nose, and throat (ENT) surgery. It is used with the patient under general anesthetic. The dissector incorporates an electrically powered handpiece and single-use, disposable cutting blades and burrs. 

“The Diego was designed in a different way than any other device of which I'm aware,” noted Perry Mykleby, senior product manager for Gyrus. The project was divided into two parts. “First, there was the background work that occurred before the project ever formally got under way. That included market and user research, as well as assembly of the design team. The next was the actual design and development phase.” The design team included members of Gyrus ENT, leaders in the ENT surgical community, and IDEO (Palo Alto, CA). “A great deal of work went into selection of both the design partner and the surgical team,” he said. “It's not uncommon for manufacturers to involve customers during the design process. In our case, the surgeons participated in the actual design exercises. When the project began, none of us had any idea what the final device would look like, feel like, or even how it would work.”

Mykleby said the designers began by listening to what surgeons had to say about the way they used this type of device. “The design team spent hours and hours in surgery, taking 982 digital images and 62 hours of digital film. All this was reviewed and analyzed to identify key issues and workarounds that the users invented on-the-fly to problem solve,” he said.

“It is a sleek product,” noted juror Denise Korniewicz, RN, DNSc, associate dean for research and doctoral programs for the University of Miami School of Nursing (Miami). To achieve a sleek design and address the engineering challenges, Mykleby said that the handpiece design came first, and “some talented engineers just made it happen. The inside of Diego is almost as cool as the outside,” he said. 

“As an ergonomic specialist, I can inspect a device such as the Diego powered dissector and speculate about its suitability to the associated surgical tasks. But what impressed me about this entry,” said Wiklund, “was the testimony from the users about how it made them more effective and efficient surgeons. Clearly, the designers worked closely with the users to understand the tool's functional requirements as well the users' needs and preferences.”

Wiklund explained that the tool packs a lot of capability into a clean form that balances nicely in the hand, keeps supply lines out of the way, and enables the user to rotate the cutting head instead of rotating the entire tool. “Aesthetically, the tool looks empowering by virtue of its engineering refinement and overall simplicity. It's no wonder it was easy for the designers to collect so many strong testimonials,” he added.

The Diego powered dissector demonstrates ease of use, said Alden. “It is a handheld device that can be operated intuitively with one hand.” He explained that when the user picks up the device, it becomes part of his or her hand, and the person's fingers instinctively “find home.” A surgical tool like the Diego should enable users to perform procedures without perceived hindrance, he noted. “Based on the task performance data provided by the manufacturer, the tool seems to do just that. The product appears to have only as much form as necessary to serve its purpose,” he said.

According to Wiklund, form has followed function in a definite manner, explaining the lack of aesthetic or pseudoergonomic adornment. In this case, he said, the lack of special ergonomic features, such as a sculptured grip, appears to ensure the device's ergonomic suitability to the task. “It does not force the users to place their hands and fingers in a specific position. Therefore, it appears well suited to varied hand sizes.”

Radically innovative? Maybe not. But, as juror Wilcox noted, “there is something to be said for old-fashioned good design.”

Copyright ©2004 Medical Device & Diagnostic Industry


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