The Benefits of LED Based Surgical Lighting

LED lighting units are becoming more and more prominent in all segments of lighting, and surgical lighting is certainly no exception. LEDs are proving to be perfectly suited for examination and surgical illumination applications, and the switch in lighting technology from halogen to LEDs is widespread. Hospitals are always interested in finding more effective ways to run their operations at an optimum level and LEDs fit the bill not only economically, but also in terms of comfort for both surgeon (who endure hours under these lights) and patients alike.

Light emitting diode surgical lights, first introduced in the United States in July 2006, were initially met with a healthy mix of interest and skepticism. Why use LEDs in the operating room (OR)? Were the proposed benefits real? Did those benefits justify turning away from proven technologies, such as halogen, especially with lives on the line in the OR?  In the relatively short period since their introduction, these questions have been answered and the validity of LED surgical lights has been confirmed by a variety of factors. 

Low heat
Reducing heat, particularly in the area of the surgeon’s head, provides a more comfortable environment with the potential to improve surgical team performance, OR efficiency, which also would improve patient outcomes. While traditional surgical light manufacturers have made continual progress to reduce the heat produced by their lights, LED technology essentially ends this battle. In fact, the heat output of LEDs is better described as “no heat” rather than “low heat,” with temperature increases in the area of surgeon’s head measured at less than 1 degree Celsius by one manufacturer.

Extended Lifespan

LED based lights offer dramatically longer life cycles over conventional halogen based lights. The expected service life for the light source used in traditional lights is upwards of 2,000 hours. Various LED surgical light manufacturers talk about dramatically different numbers. The diodes used in LED lights are manufactured to last 50,000 hours on average. LED surgical light manufacturers will either use that 50,000-hour figure or a more conservative guarantee of 20,000 hours referring to the whole light and all its components.

Quality of Light

Beyond the benefits of long life and low/no heat, which seem to dominate most conversations on LED technology, it is important from a surgical team’s viewpoint to pose more basic questions regarding the quality of the light output. Some things to consider are:

• A homogeneous light field: The quality of light is a subjective issue, with surgeon preference coming into play to explain why some lights get approval over others. Among the factors that are at work here is whether the light field is homogeneous. Surgeons are looking for consistency of the light across its focused area with no hot spots or drop-offs.
  The quality of the field is certainly affected by the configuration of LEDs in the light head, with more LEDs providing greater coverage and a better pattern. The critical assessment of the quality of the light field is best left to the surgeon’s discerning eye during a light trial.
• Focusing ability: Another basic question is how the light is focused. Some LED lights offer a manual focus but a few can be focused electronically. What is the size of the spot and quality of the focus? Again, these functions are best judged by clinical staff during a light trial.
• Intensity: The maximum allowable intensity of a surgical light is 160,000 Lux. The best traditional lights provide this level of intensity. The best LED surgical lights also meet this standard and provide dimming capabilities so a surgical team can adjust to the demands of each procedure.

Advanced Features

Depending on the manufacturer, LED surgical lights also offer various advanced features that can contribute significantly to a surgical team’s ability to deal with common problems, as well as provide them with new capabilities.

• Shadow correction: Shadows during surgery are created by surgeon positioning, surgical team movement, equipment or the depth of a wound. The key is to minimize shadows so a surgeon always has the clearest possible view of the surgical site. In a typical LED surgical light, each LED generates the entire spot. These individual spots are then precisely overlapped, so no matter how many LEDs are blocked, the spot remains round and consistent. As obstructions move inside the light field, the pattern does not change.
• Adjustable color temperature: An option currently offered by two LED light manufacturers is the ability to adjust color temperature. Color temperature is measured in Kelvin (K) with a lower number indicating a warmer, more orange light and a higher number representing a cooler, neutral, white light. The ability to adjust color temperature, not possible prior to the introduction of LED lights, allows a surgical team to improve contrast and tissue differentiation, based on factors such as the type and depth of the surgery, blood flow and a surgeon’s preference.

It comes down to a better view for a surgeon, and that can only help to benefit the patient. OR managers benefit by having one light that can address varied surgeon preferences, so staff satisfaction is increased and room scheduling is easier. The hospital benefits by being better positioned to recruit and retain qualified surgical talent. Factor in the economic advantages of consuming less electricity to power LED lights, and it’s easy to see why LEDs are the driving force in surgical lighting.

The team at Norlux will help design and manufacture your LED based examination, procedure and surgical lighting systems; call Norlux today!

Reference:

"The future of LED lighting and why surgeons prefer it: Benefits start to push new technology ahead of traditional products"

By Dave Rector, Jan 2008

http://www.matmanmag.com/matmanmag_app/jsp/articledisplay.jsp?dcrpath=MATMANMAG/Article/data/01JAN2008/0801MMH_FEA_OR_Technology&domain=MATMANMAG

Wireless Controls in LED Applications

With the advent of solid state lighting, we are now able to add intelligent controls to the lighting solutions. Already existing circuitry designed to control and dim the LEDs can easily be added on to include wireless control; a microcontroller can use its dormant Rx/Tx pins and connect to a wireless transceiver, instantly creating a wireless solution.

Wireless controls range from intelligent home automation to whole factory control. The fact that no control wires are required allows the customer to place the lighting controller wherever deemed most convenient. This means that adding a wireless switch at home would not require the costly addition of a junction box and wiring it directly to the light source. Wireless controls also allow for mobile control; from a laptop on the manufacturing floor to an iPad on your living room couch. Wireless solutions with a gateway to the internet can even be monitored and controlled from a remote location via the internet connection.

Some of the networks implemented by wireless control are mesh networks and point-to-point networks. Mesh networks occur when each light acts as an individual node, passing controlling data through the network. This allows for a larger range of communication from the initial command point as the signal gets passed from node to node until it reaches its final destination. Conversely, a point-to-point network occurs when a single remote manipulates a single light source. 

There are many different solutions to wireless control in LED applications. Some of the leading communication protocols are IR (infrared), Zigbee and Wi-Fi. IR controls, while a tried-and-true communication path, has become antiquated because its range and light of sight disadvantages have been overcome by other advances in wireless communication. Zigbee and Wi-Fi, on the other hand, take advantage of radio waves to extend the range and remove the line-of-sight requirement. 

Zigbee is IEEE 802.15.4 compliant and uses a mesh network and low data rates to connect many nodes to each other. Because Zigbee is a standard, it allows for interoperation with existing zigbee products that include many other controls then just lighting. Communication directly between a zigbee light source and a zigbee sensor can be achieved without the need for human control. The zigbee alliance boasts 64,000 individual nodes on a single network; however an extra gateway device is required to interface the zigbee communication to the internet. This means that a gateway is required if you want your PC or IPhone to communicate to a zigbee network.

Another popular communication protocol is Wi-Fi. While Wi-Fi is limited to only 255 nodes per access point (although it is often recommended that the number be less than 30), it can handle large amounts of data and is already connected to the internet via a router. This makes Wi-Fi a good choice for advanced lights that a consumer may only need a handful of.

When choosing a wireless solution for your lighting needs, it is important to consider the quantity of nodes per network as well as the need for internet connectivity. For example, many LED lights in a manufacturing warehouse can easily take advantage of a large mesh network solution that the zigbee affords. However, controlling a single strip of colored LEDs from your IPhone lends itself to Wi-Fi connectivity because it could connect directly to your router.

Here at Norlux we are committed to explore and understand all developments in wireless control of LED lighting. If you are interested in a wireless LED solution, please contact the engineers at Norlux.