2013-07-03
Life-Saving LEDs
In applications from medicine to mining to suicide prevention, LEDs aren't just improving the quality of life, they are preserving lives.
We can all recite by rote the usual advantages LEDs offer over other lighting solutions: longer life, greater energy efficiency, greater flexibility in color and control, and lower maintenance costs. We don't usually think of LED applications providing even greater value, indeed the ultimate value: saving lives. But some applications arguably do this.
Medical
The first application that comes to mind is one we discussed here a couple of months back: blue lights to treat jaundice. "Bili lights" and "bili blankets" existed before the advent of LEDs, but the new technology has increased their efficiency by sharpening the control of the light spectrum used to encourage human bodies to get rid of bilirubin from the bloodstream.
We may not normally think of the pulse oximeter, the fingertip device that non-invasively measures the oxygen content of blood, as a life-saver. But in some circumstances it is exactly that. A report in EDN claims that over the last three decades, when this device has been in use in operating rooms, there has been "a marked drop in catastrophic anesthesia malpractice claims." It is notoriously difficult to recognize the distress from anesthesia when the blood oxygen level dips dangerously low. Other factors may be involved, but the LED-based pulse oximeter has to take some of the credit.
Mining
In the mining arena, at least two peer-reviewed studies indicate that LED lighting improves miner safety, at least potentially. Researchers at the National Institute for Occupational Safety and Health studied 30 miners in three age ranges to see whether LED-based cap lamps could improve safety, and concluded:
Results suggest that LEDs with a visible spectrum containing a higher concentration of the shorter wavelengths can enable visual performance improvements with respect to disability glare, the detection of moving hazards in the peripheral field-of-view, and the detection of floor hazards in the forward field-of-view.
Some of the same workers looked at mining accident records with an eye to whether LED lighting could reduce injury severity and frequency, and concluded that "low-power and lightweight auxiliary LED lighting for surface mines could also have potential impact for improving safety." But that study concluded that the greatest benefit was provided by LEDs' reduced need for maintenance.
Suicide prevention
Samsung Life Insurance sponsored an ambitious project to reduce the incidence of people jumping to their deaths from the Mapo Bridge in Seoul, Korea. One can see why the company was anxious to reduce the suicide rate. According to a writeup on the site of the ad agency Cheil: "Suicide is one leading causes of death in South Korea (No. 1 among OECD countries) and the largest reason for insurance payment at Samsung Life Insurance."
The "Bridge of Life" project features proximity sensors that react when someone approaches the guard rail, and trigger one of over 2,200 LED lights illuminating either a lighted panel or "messages approved by suicide prevention groups" ("What is troubling you?," and "Just go and see the person you miss," and the like). From the video embedded at the SmartPlanet link above, it looks as if the lighted messages are static and at fixed locations along the bridge. To my Western eyes it all seems rather a cold and mechanical approach when addressed to someone ready to take his or her own life. But the statistics bear witness to its effectiveness: The suicide rate had dropped by 77 percent since the installation went in last fall.
Granted, the Bridge of Life could have been implemented with incandescent or fluorescent or another lighting technology. But the control aspects are simplified by using LEDs.
Are there other life-saving applications in which LEDs play a part?
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— Keith Dawson 
, Editor-in-Chief, All LED Lighting