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"Price is always a factor," added Dave Rector, director of marketing, TRUMPF Medical Systems, Inc, Charleston, SC, "but quality of patient care is the real key. Facilities need to look for solutions that deliver the best combination of benefits that are not only financially feasible but can also help their staff provide the best possible patient care."

What do buyers and users need to know about surgical lights to make a good purchasing decision? HPN talked with some surgical-light experts who offered advice. All agreed on key features: intensity, color temperature, heat control, shadow control, maneuverability, flexibility, and surgeons’ comfort.

"Certain surgical light features are more important to surgeons, while others are more important to staff," said Pam Rockow, senior product marketing manager, MAQUET Surgical Workplaces, Getinge USA, Rochester, NY. "Surgeons want good quality light with a nice even patch, free of hot spots and shadows, with good color rendering that allows them to clearly differentiate healthy from unhealthy tissue and giving them the ability to see into deep cavities without the need to refocus. Nursing staff will look for easy maneuverability, easily accessible handles for repositioning, light heads that do not drift, and bulbs that are easy to change."

"Light intensity, heat generation, shadow control, and the ability to focus the light effectively are all important from a surgical perspective," added Rector. "The life cycle of the light source is important in terms of scheduling and costs. From a management standpoint, longer life cycles minimize interruptions in the operating room (OR) schedule, improve efficiency, and reduce hospital costs."

The MAQUET PowerLED surgical light, Getinge USA

Intense light is important to surgeons, but this isn’t a case of "if a little is good, more is better." "Surgeons need intense light," said Walters, "but if it’s too intense, it could burn the patient."

Light intensity is measured in units of lux. Most surgical lights are 80,000 to 160,000 lux. STERIS’s Harmony LA Surgical Lighting System reaches the maximum 160,000 lux, in accordance with standards of the International Electrotechnical Commission (IEC), a leading global organization that prepares and publishes international standards for all electrical, electronic, and related technologies.

Skytron’s Stellar Lighting System also reaches 160,000 lux. Randy Tomaszewski, vice president, marketing, Skytron, Grand Rapids, MI, offered another reason for achieving the right balance in intensity: "Light too intense, too blindingly white, exhausts the surgeon’s eyes."

MAQUET surgical lights are different. Rockow explained: "Whereas other manufacturers use converging and reflective technology, MAQUET surgical lights use diverging and refractive technology, which delivers thousands of individual overlapping light beams. One misconception in purchasing a surgical light is the need for high lux. Brighter is not better. Our lights don’t have high lux due to the technology and optical system. High lux causes strain on the surgeons’ eyes, reflection off instruments, etc. Shadow control, light consistency, and volume of light are virtually no problem, because no matter where the surgeon’s head is positioned, the individual beams of light are compensated. Because of the technology, the light doesn’t need high illumination levels to reflect around the surgeon’s head."

Color temperature is measured in degrees Kelvin (K). Sunlight at noon measures about 5,000 K; the light bulbs in houses and stores are between 2,000 K and 3,600 K; most surgical lights are 4,000 K to 4,500 K.

The color rendering index (CRI) is a scale used to measure a light source’s color characteristics—vividness, discriminability, and naturalness—with 100 representing the maximum value. Again, this is not necessarily a case of more is better, explained Tomaszewski: "If the light is too white, which is close to 100 on the color index; the surgeon will see sun spots. Most surgical lights are in the 90 to 95 range on the CRI. Surgeons need soft white lights with high intensity to illuminate deep recesses in the patient’s body."

Incandescent light generates heat. The trick is to balance intense, soft white light with a comfortable temperature for the surgeon. "Surgeons may stand for 6 to 8 hours," observed Walters, "so surgeon comfort is a big deal. Cool operation of a surgical light is necessary."

"Heat is a significant factor," agreed Rector. "Obviously a light that gives off more heat can have a negative impact on surgical-team comfort and performance, particularly in longer procedures."

Reflectors are employed to control heat in some surgical lights. Walters explained how it works: "STERIS’s Harmony surgical lights have a special coating and cold-mirror reflection designed to reflect the heat out the back of the light while the cool light illuminates the surgical site."

Lights and shadows go together like Tom and Jerry: where there’s light, there’s usually shadow. Shadow often is created by the surgeon’s head, because it falls in between the light and the surgical site. "Shadows exist," acknowledged Rector, "but the key is to minimize them, so the surgeon always has the clearest possible view."

"The goal is to produce intensity with a minimum of heat and soft, rather than harsh, shadows or no shadows," said Tomaszewski. It’s critical that shadows don’t block the lighting. Soft shadowing allows for depth perception, gives it the 3-D look. Black shadows are not good."

TRUMPF iLED

"Flexible lighting systems give surgeons the ability to treat anything," said Tomaszewski. "It’s better to have and not need than to need and not have when it comes to surgical lighting. For example, the surgeon never knows whether, during a minimally invasive procedure, complications might occur that would mean opening up the patient. The necessary light must already be in place for such unforeseen events."

Tomaszewski added: "Surgeons need surgical lights that are lightweight, so they’re easy to maneuver, and have the flexibility to deliver light where needed. For maximum flexibility, lights need to rotate 360°. Lights should hold their position. The surgeon shouldn’t have to be a mechanic to operate a surgical light."

STERIS’s Harmony LA Surgical Lighting System is compact, which helps toward maneuverability. Rather than one large light head, which can drift because of its weight, two of their smaller lights can be brought together for more flexibility and ease of use.

Another important aspect of
flexibility is integration. Rockow pointed out that the ability to integrate is vital in today’s market. "Any new construction uses integration systems to control cameras, patient monitoring, display monitors, and so forth. The arms of the suspension systems must have enough space to run cables easily. MAQUET lighting systems are compatible with other vendors in this respect."

"It’s hard to predict how the OR’s needs will change," Walters told HPN. "STERIS prepares for that by designing modularity into the system. We can add a light head or a flat-panel monitor later, expanding as needs change. Also, our monitor arms are pre-cabled to accommodate every current vendor’s signals, so the cables don’t need to be ripped out if the facility changes to a different vendor or added in after installation as the OR evolves."

It seems that everyone is jumping on the LED bandwagon, and no wonder: the advantages are multiple and serious. STERIS’s Walters explained: "The LED has a much longer life than a halogen bulb, 20,000 hours of light versus 1,000 hours. It’s approximately 30% cooler than incandescent lighting. LED uses less energy, which creates less heat. LEDs also give manufacturers more flexibility in design. Up to this point, surgical lights have looked similar. LEDs will replace reflectors and will therefore be able to be arranged in innovative ways. A drawback of traditional surgical lights is that, as the light pattern becomes bigger, intensity is lost. LED technology will change that as well. Another difference is that incandescent light bulbs blow out and need to be replaced every 3 months, whereas LED lights will last 7 to 10 years, will fade away over time, and will need to be replaced all at once. What LEDs will be replaced with we don’t know at this point; maybe the whole light head will have to be changed. This is 10 years away, so we’ll have to see how it plays out."

Rector also expounded on the virtues of LED: "The TRUMPF iLED series has up to 184 white and color LEDs, providing up to 160,000 lux of low-heat, virtually shadow-free illumination. The iLED light field is adjustable from 11.5 to 8.6 inches. Heat increase at the surgeon’s head is less than 1°C, a significant benefit in terms of surgeon and surgical team comfort. The iLED compensates for even extreme shadowing created by surgeon positioning or the depth of the wound, by providing settings that switch off unnecessary LEDs and increase the intensity to the remaining ones, depending on the surgical situation, without repositioning the lights during surgery."

"The iLED offers the ability to change color temperature without affecting light intensity, which provides optimal contrast and tissue differentiation. A single light allows surgeons to change color temperature from 3,500 K to 5,000 K, without affecting light intensity. By adjusting color temperature, the surgical team can optimize contrast and tissue differentiation, based on factors including the type and depth of the surgery, blood flow, surgeon’s preference, and even his or her degree of eye fatigue. The key to adjusting color temperature is in the ability to change the ratio of white to color LEDs, thus ‘mixing’ the desired color tone. Bathed in warm, nonglare light (about 3,500 K), skin and light-tissue parts reflect less, and the contrast remains intact. Colder light colors (up to 5,000 K), however, are preferred for deeper-lying body areas and for longer surgeries. When eyes are tired and concentration lapses, we perceive cold, or blue, color tones as a relief to the eye. Either way, the surgical team, whether working on shorter outpatient procedures or longer surgeries, has their choice."

The TRUMPF iLED is equipped with a sterile control unit, which permits the surgical team to control all functions, including on/off, dimming, color temperature, shadow correction, and camera functions quickly and easily. Both the TRUMPF iLED 5 and the new iLED 3 are available with TRUMPF’s new integrated TRUMPF TruVidia CCD camera, which provides razor-sharp, true-to-life video and still images. A new iLED, ideal for emergency ICU procedures, is also scheduled to be released in late 2007.

STERIS Harmony LA surgical suite

Skytron expects to release their new LED light, Aurora LED, in mid-summer. Tomaszewski touted the wonders of LED. "The advantages of LED are ten-fold in terms of energy conservation. LED also will allow for selectivity of color temperature: whereas some surgeons prefer bright white light, others prefer a softer white. The unique property of LED cells can change focal length of the light with multiple reflectors, allowing for deep cavities to be intensely illuminated without deep shadows."

MAQUET’s new PowerLED provides a cool working environment for the surgical team, prevents tissue from drying out during an operation, and has a long illumination life, delivering 30,000 hours of light versus competitors’ 20,000 hours. This is due to its open-ring design, which allows heat to dissipate out the back of the light. Although LEDs produce virtually no heat at the surgical site, the electronics within the light head do. "Getting rid of the heat prolongs the life of the LED, which allows us to obtain a longer lifetime of approximately 4 years," said Rockow.

PowerLED uses individual Fresnel lenses, incorporating the same refractive, diverging technology found in other MAQUET lights. PowerLED has 168 individual LEDs, each producing an 8.3-inch patch, allowing for superior shadow control. "Having a large number of LEDs reduces service and replacement time and cost, as well as having less impact on illumination should you lose a small percentage over time," said Rockow. "PowerLED has no moving parts, there are no motors, and no adjustment is needed because it’s focused all of the time."

At the end of this year, MAQUET will offer a patented, optional feature called "Automatic Shadow Compensation System." No manual adjustment will be needed because sensors in the light will darken LEDs directly above the obstruction, such as equipment or the surgeon’s head, and increase the illumination of those not blocked.

"Anyone can produce light," said Rockow. "The difference—and it’s an important difference—is the quality of the light and how it’s delivered."