Reestablishing Sleep and Circadian Alignment in Medical Intensive Care Unit (MICU) Patients Via a Mechanistic RCT of an Sleep Chronobundle

"Bright daytime light from 09:00 to 13:00 starting on day 1. The light will be 10,000 lux at 12 and provide a minimal intensity of 1,250 lux at the angle of the eye (30 to 36 distance). The light has a temperature of 5,000 Kelvin indicating a high blue wavelength content which should maximize circadian effects (validated device Sunbox Lighting, Maryland). Following the 09:00 to 13:00 bright light, the room lights will remain on and the curtains will remain open to maximize daytime light exposure while not decreasing bright light tolerance."

For patients receiving enteral feeds, time-restricted (daytime) intermittent feeding will include 4 meals delivered at 08:00, 12:00, 16:00 and 20:00. Each meal will include one-fourth of the recommended daily tube feed volume.

While in the MICU, exercise/mobility sessions led by physical therapy or occupational therapy providers will occur twice daily between 09:00 and 16:00 (i.e., one additional session beyond usual care); intensity will be determined by clinical status and documented in the chart by our physical therapy service. Patients in other hospital locations (e.g., general medical ward post-MICU discharge) will receive one additional session beyond usual care via a study staff-led exercise/mobility session; intensity will be determined by clinical status.

Overnight sleep promotion will occur between 22:00 and 06:00 with a more restricted sleep period between 00:00 and 04:00. This will be achieved by rescheduling non-urgent care. There will be no changes to urgent care. Additionally, room lights will be dimmed, curtains drawn, and room doors closed. Television screens will be fitted with blue light-blocking filters.