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.

Inclusion Criteria:

- American Society of Anesthesiologist Classification of 1,2

- Patients ages 2-6 years

- Routine tonsillectomy and adenoidectomy

Exclusion Criteria:

- American Society of Anesthesiology classification other than 1,2

- history of migraine headaches

- ocular disorders

- seizure history

- psychiatric conditions

- parental refusal

- developmental delay

- patients on medication for attention deficit disorders or caffeine stimulants.

- Patients with contraindications to receiving inhalation agents,

- Use of premedication with midazolam or dexmedetomidine.