Effect of Monochromatic Light on Incidence of Emergence Delirium in Children

Emergence delirium/emergence agitation (ED/EA) is a behavioral phenomenon of unclear etiology consisting of short lived behavioral changes that can be both traumatic to families and pose a safety risk to patients and staff. ED is characterized by a variety of presentations, including crying, excitation and agitation, that occur during the early stage of recovery from general anesthesia, generally in the first 30 minutes. Involuntary activity in the bed and even thrashing about during an episode of ED can lead to dislodgement of IV cannulas, surgical dressings and or surgically placed items such as drains and catheters. Emergence delirium occurs in children of all ages following an anesthetic with halogenated agents (e.g. sevoflurane/isoflurane) with or without having undergone a surgical procedure (e.g. MRI patients). Electroencephalograms (EEG) in patients experiencing emergence delirium show diffuse background slowing. Presently, the treatment for ED is to revert the patient back to a hypnotic state mainly with sedatives so that they may "reset" themselves postulating that by re-inducing a hypnotic state, the brain has time to resolve this issue. The hypothesis of this study is that during ED, there is failure of organized EEG activity, especially alpha wave activity and that by enhancing alpha activity, the incidence of ED may be reduced without the need for additional pharmaceuticals which may be costly, delay recovery and are not without adverse effects specifically cardiopulmonary depression.

Monochromatic light (ML) has been used in a variety of clinical and non-clinical applications to affect a variety of changes. Exposure to light of short wavelength within the visible spectrum (450-470nm) has been associated with effects on circadian rhythm, neuroendocrine and neurobehavioral changes and enhanced cognitive performance. Blue ML has been studied safely to enhance work-place alertness and productivity. Clinically, blue ML has been used safely for decades in the neonatal intensive care unit to treat jaundice.

Blue ML, has been known to suppress melatonin secretion and enhance alertness and workplace performance. The effect occurs within the retinal photoreceptive ganglion cells which mediate the observed responses. The effect is even present in visually blind persons lacking outer retinal function. Short exposure to bursts of blue light has revealed enhanced neural activity on functional MRI. Use of blue ML has been shown to enhance EEG activity in the alpha range (awake range) compared with light of greater wavelengths. Using blue ML in the operating room may enhance alpha EEG activity, (a circadian marker for alertness) it may be possible to reduce the incidence of emergence delirium in the post-operative period and therefore the amount of (non-pain) sedative medication needed in recovery.