New research suggests that circadian lighting in the ICU may improve the outcomes of these very ill patients, both now and up to a year after their hospital stay.

More than 4 million patients are admitted to the ICU, or intensive care unit, every year. These units offer the one-on-one nursing care and high technology that our nation’s sickest patients need. Due to high mortality rates among these very ill patients, 10 to 30 percent don’t ever leave the hospital. Of these survivors, many will be back in the hospital within just a few months. Many studies have been performed looking at ways to help these incredibly ill people regain health permanently, reducing the financial and human cost of the serious illnesses or injuries that require ICU care. New studies suggest that simple changes in lighting could help ICU patients fare better both in the hospital and in the year after discharge.

Circadian Lighting in the ICU: Short and Long Term Effects

Like many hospital rooms, ICU rooms tend to have the same fluorescent lighting 24 hours a day. Researchers modified this lighting so it changed throughout the day in a similar way to natural outdoor light. Mornings began with weak light heavy in warm red tones that resembled dawn. At 8 AM, stronger blue lights took over, gaining strength throughout the day. The light began to get dimmer and warmer again in evening when light sources shifted to lower height levels. Later at night, the only light was weak and warm lights from the baseboards.

Patients said that they preferred this lighting, which helped them to gauge the time of day at a time when many are drifting in and out of consciousness. They rated their recovery better when they were discharged. More importantly, they had higher recovery ratings even a year after leaving the intensive care unit. Circadian lighting appears to not just help orient patients, but to have other health effects as well.

Lighting appears to be especially important in intensive care units, where 24-hour bright light combined with many patients entering in an unconscious state can cause disorientation. Patients found the circadian lighting to be soothing and reported that it calmed them while making it easier to orient themselves. Patients also had a lower incidence of delirium, a mental disorder that strikes many ICU patients.

The Importance of Lighting in Healthcare Settings

This is not the first or only chronobiology study to find that lighting in hospital settings can make a meaningful difference. Prior research has found that exposing mice to blue light in the 24 hours before surgery can reduce adverse events such as inflammation and organ damage. It appears to work by lowering the levels of inflammatory mediators in the bloodstream. This can reduce swelling, pain, and other common post-surgery complications. These are common barriers to healing, so it stands to reason that humans may fare better when pre-operative rooms use this wavelength of light.

Imagine hospitals with light designed to benefit patients most at crucial parts of their healthcare process. This may be the future of medicine. Controlling lighting is a cost-effective way to improve patient outcomes in a world where many are searching for ways to make hospitals safer, cheaper and more effective. Our circadian rhythms do not stop when we are sick, so we may indeed heal better when our internal clocks are kept functioning as well as possible during one’s time in the hospital.