Stand under an LED surgical lighting unit for a few minutes and you'll notice 2 things: The light is brighter than the surgical illumination you're used to, and the top of your head isn't warming up the way it does when you stand under a halogen light. Yes, light-emitting diodes are brighter and cooler than halogen or incandescent bulbs. They last longer and use less energy. Here's what sets one LED lighting system apart from another.

1. Color and temperature. Some LEDs give off a warmer, more yellow or red hue while others give off a more intense, blue-tinted light. Manufacturers use 2 numbers when referring to the color of their lights.

• Color temperature. This measurement is defined in degrees Kelvin. A halogen light tends to be more yellow, with a color temperature in the sub-3,000 Kelvin range. "As you go higher in that color temperature reading from 3,000 to 4-, 5-, 6,000 Kelvin, the middle range tends to be more natural. As you get further up, the lights will tend to get bluer," says Chip Losee, operations manager for Huot Instruments.
• Color rendering index. CRI measures color temperature relative to natural sunlight at 100%. The higher your CRI value, the more "natural" the light given off by the LED. Many companies boast surgical LEDs with a CRI of 90 or above. Being able to render the colors that are illuminated as naturally as possible "helps surgeons distinguish good tissues from bad tissues," says Chad Bittner, senior product manager of ceiling systems for Steris Corp.

2. Intensity. Light intensity is typically measured in lux or foot-candles, with about 160,000 lux being around the maximum intensity for surgical LEDs. While many manufacturers boast that their lights are set around the maximum intensity, that number may not matter in the OR. "There is a point where some people feel you can make a light too bright so that you get glare in the surgical field," says medical equipment planner Lynne Ingle, RN, BS, MHA, CNOR, of Gene Burton and Associates. Many lights offer the option of adjusting the intensity to suit the needs and preferences of different surgeons and procedures.

Another aspect of intensity to consider is duration and stability: Do the lights stay at the same intensity from the beginning of a long procedure through to the end, or do they begin to lose strength? How about over the entire life cycle of the LED? Although the LEDs themselves should almost never burn out, they will decay and lose output over time, says Brett Messina, director of sales and marketing for Nuvo. In Nuvo's surgical LEDs, a service light will go on when the LEDs begin to decay, and the company will come in and boost the lights back up to 100% output so that the quality of the intensity remains constant, says Mr. Messina.

3. White vs. multi-colored LEDs. Some companies boast "all-white" LEDs, while others tout the benefits of their multi-colored LEDs. What's the difference? And, perhaps more importantly, does it matter? Mr. Messina says having multi-colored LEDs lets Nuvo maintain a constant CRI through different intensity settings. Frank Alles, head of international sales support for Maq-uet's surgical lights, counters that multi-colored LEDs run the risk of casting colored shadows on the surgeon or surgical field. David Church, marketing product manager for Stryker's booms and lights, says it's the pure-white nature of his company's surgical LEDs that "provide the best illumination." Due to the conflicting nature of the manufacturers' claims, this may be a feature that comes down to surgeon and staff preference.

4. Shadow control. In addition to how bright the lights can get, you'll want to test whether that intensity is balanced by what Mr. Alles of Maquet calls "shadow dilution." "You hear that an OR light has to have no shadows — not true. You need some in order to view depth and 3 dimensions," says Mr. Alles. But what you don't want is a large, dark shadow cast over the table when, say, the surgeon or circulator sticks his head directly under the light. When trialing lights, make sure you can place an obstruction between the light head and the table but still get a clear, illuminated view of the surgical site.

5. Spot size and focus. When the lights are turned on, do they bathe the room in a wide glow of bright light, or do they provide a sharp beam directly on the surgical field? You'll want to consider the potential uses of the lights (What types of procedures are going to be performed in that room?) and whether they're up to the challenge of, say, deep-cavity open procedures or cases covering a large surface area vs. smaller, more targeted surgical sites — or all of the above. And then there's the question of control and adjustability. For example, Stryker says its LEDs provide a large, continuous spot size throughout the depth of field, so whether you move the table or go into a cavity mid-procedure, you don't have to adjust the light. Skytron, on the other hand, is all about surgeon control and adjustability, says Senior Product Manager Harold Koltnow. "Surgery light is not about flooding an area with very bight light. It's about being able to focus the light on the target area that you're working on," he says. Skytron has included controls on the center handle of its light heads, which surgeons can use to adjust the light's focus and intensity mid-procedure without leaving or taking their eyes off the field.

6. Dimming capabilities. By giving you the option of adjusting the intensity of the light, many LEDs are equipped with dimming capabilities — a necessity for minimally invasive procedures that require a darkened room for optimal visualization. In these cases, you can't simply turn off the overhead lights, leaving anesthesia providers and nursing staff in the dark. For white LEDs, being able to turn down the intensity just enough so the room is dimmed but not completely dark lets support staff continue working while the surgeon is looking at the video monitor.

Alternatively, some LEDs have a "green mode" in which all but a series of green LEDs are turned off, bathing the room in a green glow, which Mr. Messina says is better than traditional dimming because "the human eye can see more shades of green than any other color." However, the green light option tends to be a matter of personal preference, says Ms. Ingle. "Some people really like it; some people think it's a bunch of baloney. It's in the eyes of the beholder."

7. Durability and service. One of the greatest benefits of LEDs is their potential to save you the long-term hassle and cost of replacing your light sources. While more expensive up-front, LEDs are designed to last tens of thousands of hours, as long as 15 to 20 years. However, they're not going to stay in mint condition for that long. Consider the durability of the light head itself relative to the LEDs contained within. Although LEDs are much cooler than halogens, they still emit heat, and over time that can wear away at the light head. Some LEDs are able to do more with fewer actual LEDs (and therefore less heat) through carefully designed reflectors that enhance the light's intensity and range. Pay close attention to the quality of the materials and what the vendor is willing to offer in terms of service and upgrades down the road. "LED lighting is a new technology," says Mr. Koltnow. "It changes every year." Make sure that future improvements can be made to your lights with as little hassle and downtime as possible.

8. Cost. Of course, cost is a major issue with a capital equipment purchase like surgical lighting. Ms. Ingle says LEDs are typically more expensive than traditional surgical lighting units, although Sunnex, a newcomer to the surgical LED market, says it will price the new lights it's unveiling later this year comparably to halogens. When analyzing the costs of switching to LEDs, you'll want to take into account their durability and reduced energy consumption compared to halogen lights, as well as what the vendor is offering in terms of service over the life cycle of the system. Most companies offer a standard 1-year warranty on LED surgical lights, although some offer warranties lasting as long as 5 to 10 years. There is also wide variation in the market between basic LED lights and more advanced lighting systems with options like HD video integration. If you're considering an integrated OR either now or down the road, ask if LED vendors will work with any HD system or boom vendor, or if they require that you purchase all the equipment through them or their affiliates.

See for yourself
The best way to find an LED lighting solution that suits your facility's needs and budget is to conduct a thorough, hands-on trial. "To me, the most important factor to consider is whether the lights are acceptable to the physicians who will be working under them," says Ms. Ingle. Most vendors should be willing to bring their LED lights into your facility and install them for a trial period, but don't invite everyone, she warns. Because of the logistical hurdles and the risk that, by the time the trial is over, you won't remember which lights you liked best, try to settle on about 2 or 3 top contenders before you do an on-site trial. Go on site visits to other facilities and check out the different vendors at trade shows, then consider cost and service to narrow down the playing field. Ultimately, you'll need to weigh your current and future needs against what your budget will allow to find the best possible solutions for your facility.