Daytime Bright Light, Circadian Abnormalities, and Delirium in Medical ICU Patients

To determine if daytime bright light will promote circadian alignment and shorten or prevent delirium. The objective is to conduct a randomized controlled trial to determine if a circadian entrainment intervention, daytime bright light, will promote circadian alignment and reduce days of delirium

Inclusion criteria

• Hospital admission ≤30 hours at noon on enrollment day
• Expected to say in the Medical Intensive Care Unit (MICU) ≥24 hours after enrollment
• Age ≥50 years

Exclusion criteria

• At significant risk for pre-existing circadian abnormalities:

• Severe chronic brain injury (Injury greater than 30 days ago resulting in the inability to live independently)
• Acute brain injury of any severity (Injury less than 30 days ago including acute intracranial bleed, traumatic brain injury, central nervous system infection, tumor)
• Documented circadian disorder or blind/disease of the optic nerve
• Current history of substance abuse including alcohol (use in last 30 days)

• Transferred from an outside hospital. 4. History of bipolar disease 5. Paralyzed (due to injury, disease or medications)

Enrolled patients who do not stay in the MICU through 13:00 of Study Day 2 will be excluded; patients transferred from the MICU to the floor between 22:00 and 05:00 on subsequent study nights will continue in the study but be excluded from the primary analysis (estimated 10% of patients).