Reading room requires attention to ergonomic issues

Oct 3, 2010

As radiologists spend an increasing amount of time at their workstations, they also face an elevated risk for repetitive motion injuries and cumulative trauma disorders. As a result, sound ergonomic practices are very important, according to Steven Horii, MD, of the University of Pennsylvania Medical Center in Philadelphia.

The digital reading room requires careful attention to the principles of ergonomic design. Fortunately, relatively simple steps can be taken to reduce the risk of work-induced injury, Horii said.

Ergonomics is based on the principle of neutral positioning of the body and extremities, as well as avoiding behaviors known to be deleterious over time, Horii said. Important environmental design elements include lighting, HVAC (heating, ventilation, air conditioning), acoustics, and workstation furniture.

He discussed the need for ergonomics in radiology during a session at the 2010 Society for Imaging Informatics in Medicine (SIIM) meeting in Minneapolis.

Lighting

Even in the days of film reading, ambient lighting that was too high was shown to have a detrimental effect. And several studies have shown that this still holds true for soft-copy reading, according to Horii.

Unfortunately, many books on workstation design use data from video display terminals, which are high-contrast, high-luminance displays. As such, their recommendations for general ambient lighting would result in a room that's too bright for radiology, he said.

A typical error is to use standard down lighting. Lighting should be bright enough for housekeeping staff, but make sure it can be switched off completely, Horii said.

In a reading room, the ambient luminance should be about equal to the average luminance of the images on the workstation, he said. This reduces pupil fatigue.

The ambient lighting should be low-glare; this is best achieved with indirect lighting that's reflected from the ceiling, walls, or both. Therefore, light is diffused and glare is reduced, he said.

Horii also noted that lighting at correct ambient levels may be too low for some tasks. As a result, task lighting should be provided via switchable, dimmable, and directed lighting.

HVAC and acoustics

Institutions should work with architects and engineers on HVAC requirements for their reading room.

"Be sure that they know about the number of workstations and people that are going to be in the room," Horii said. "People are a source of heat."

Glossy, hard sources should be avoided due to their effect on room acoustics, according to Horii. Cloth-covered partitions may help in "ballroom"-type reading rooms.

Also, research from the University of Maryland found that noise generators designed for use with speech recognition systems can improve recognition, he noted.

Furniture

Horii recommends avoiding built-in casework, as technology changes may make fixed furniture obsolete. Instead, he suggests choosing from the wide range of modular, reconfigurable furniture available in the marketplace.

While adjustability is important, it can also become a problem, Horii said.

"It should be possible to make important adjustments quickly, or people won't make them," he said.

Motorized tables that can store several user preferences are available, but that's not the case for monitor mounts and seating, Horii said.

Since radiologists may spend up to 10 hours in a reading room, it's worth their while to spend five minutes adjusting the furniture to their needs, he said. Assigned reading stations can reduce this problem.

Positioning

A number of steps can be taken to ensure proper positioning. For example, with a single monitor the centerline should be entered in your field-of-view, Horii said.

The monitor should be positioned at a distance of an arm's length with your back against the back of the chair. The height of the monitor should also be at a height of about 2 to 3 inches below the top of the monitor case, he said.

The monitor height is an important adjustment, as a monitor that's set too high will result in constant extension of the neck. A monitor that's set too low will have the opposite effect, Horii said.

"You are striving to have your neck be in a neutral position most of the time," he said.

Radiologists who wear bifocals may have to set the monitor slightly lower and tip it slightly, Horii noted.

With two-monitor workstations, set the monitors so that your line of sight falls in the center of the two displays, he said.

"Move the monitors so that they are as close together as possible and angle them toward you about the vertical centerline of the monitors," he said. "This reduces the amount of time you have to turn your neck. Again, you're trying to reduce repetitive motion."

Keyboard

The keyboard should be positioned so that your forearms are parallel with your thighs when your feet are flat on the floor, Horii said. Forearms should be angled down slightly or at a right angle.

"If possible, use a keyboard tray that tilts downward (away from you) and set the tilt so that your wrists are neutral (neither flexed nor extended)," he said.

The keyboard space bar should be centered directly in front of you, Horii said. Also, a wrist rest should not be used, as it puts pressure right on the carpal tunnel area.

If chairs have forearm rests and they are adjustable, they can be set to position your forearms at the right angle and height to work on the keyboard, he said. This can reduce stress on the biceps.

As for the mouse, radiologists should be able to locate the mouse to be used by whichever hand they use it with. Keyboard trays should either have mouse trays or have mouse surfaces that can be readily changed to either side, according to Horii.

In using the mouse, it's important to keep the elbow close to the body and try to keep the forearm relaxed. Also, move the mouse by rotating and extending or flexing your forearm at the elbow, he said.

"Avoid using the wrist for these movements," Horii said.

Also, avoid using a mouse that requires deviation of the wrist. And if possible, try to reduce the use of the scroll wheel, he said.

Chair

Chair height should be set so that you can work the keyboard and mouse properly, Horii said.

"If this means that you cannot easily put your feet on the floor, use a footrest," he said. "You should sit fully back in the chair and lean back slightly from vertical."

Your back should also maintain its normal lordotic curve, and a lumbar pad can be used for lower back support. The seat depth should position the popliteal fossae slightly forward of the seat cushion's front, he said.

As for what not to do with your chair, be sure not to tuck your feet under your chair seat, Horii said. This stresses your ankles and knees and compresses the popliteal veins.

"If possible, do not lean forward to look at your monitor screen," he said. "Doing so frequently likely means your monitor is positioned too far away or is undersized for the task."

Also, it's important to take breaks and stretch, Horii noted.

Some folks even advocate alternating between sitting down at the workstation and standing up, according to Horii. However, there's no documented evidence that this is beneficial.

In other issues to be aware of, studies have shown that long-term workstation use may worsen or induce myopia. In addition, a computer user's blink rate drops markedly during workstation use, increasing "dry eye" and the risk for corneal abrasions, Horii said.

"With film reading, the way we did things provided built-in breaks from prolonged staring at the film on the lightbox or alternator," he said.

Horii recommends that every 10 minutes, users should take a 20-second break to look at something at least 20 ft away.

Value

A properly designed workspace can be quite valuable, perhaps as much as 8% of an employee's salary, according to architect Michael Brill. Also, the American Society of Interior Designers has found that workspace design was one of the top three factors contributing to job satisfaction, Horii said.

Architects can be useful, as they are trained to balance workflow needs with design, understand workspace ergonomics, and make use of evidence-based design, Horii said. A noteworthy trend is the move toward evidence-based design, as architects are beginning to ask whether some design elements are based on scientific evidence.

Horii also noted the effect of building psychology, as spaces can have a psychological effect on occupants. Architects try to incorporate design features that have a demonstrated positive impact on patients and staff.

While having a view outside may help patients feel more relaxed, reading rooms unfortunately do not tend to have windows with an outside view. If they do, the windows are usually covered, Hori said.

"One of the things I've been advocating in new reading room design is I want an alcove off the reading room with a window you can see out of," he said. "This would be a good area for a short break."

By Erik L. Ridley
AuntMinnie.com staff writer
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