Inclusion:
- Critically ill patients admitted to the MICU who require mechanical ventilation, noninvasive ventilation, high flow nasal cannula, or vasopressor support and who remain on qualifying support as of 09:00 on study randomization day. Randomization will occur on the second or third calendar day following MICU admission. MICU admission must have occurred within 24 hours of hospital admission.
- Age greater than or equal to 18 years old.
Exclusion:
- Not expected to remain in the MICU for at least 48 hours post-randomization.
- Imminently dying or with a hospice status.
- At significant risk for pre-existing circadian abnormalities including: (1) severe chronic brain injury (injury greater than 30 days ago resulting in the inability to live independently); (2) acute brain injury of any severity that is reasonably expected to impact the central circadian clock (e.g., cardiac arrest); (3) documented circadian disorder (<1% population) or blind/disease of the optic nerve; (4) current or recent (last 1 year) shiftwork; and (5) homelessness, incarceration, or institutionalization.
- At elevated risk of aspiration due to structural or functional abnormality of the gastrointestinal tract OR fed via enteral nutrition (e.g., "tube feeds") prior to ICU admission.
- Admitted to the ICU for treatment of diabetic ketoacidosis or hyperosmolar state; this diagnosis will be established via review of the medical record for a description of diabetes in the past medical history or the presence of diabetes medication on the confirmed home medication list AND hyperglycemia attributed to diabetic ketoacidosis or diabetic hyperosmolar state by the admitting care team in their written assessment of the patient.
- Having a history of hypoglycemia without documented full neurological recovery; this diagnosis will be established via review of the patient's past medical history in the medical record;
- Having a history suggesting an abnormally high risk of suffering hypoglycemia (e.g., known insulin secreting tumor, history of unexplained or recurrent hypoglycemia or fulminant hepatic failure); this diagnosis will be established via review of the patient's past medical history in the medical record.
- Admitted due to complications of a suicide attempt.
- Admitted due to an acute drug overdose or active alcohol withdrawal.
- Positive for SARS-CoV.
Urine 6-sulfatoxymelatonin measures will be considered for all patients who make sufficient urine and have an appropriate bladder catheter in place during the indicated time points. However, we will exclude patients from urine measures if they have a history or positive test for any known disease or illness that would categorize biological samples as BSL3 or higher. This includes HIV, West Nile virus, Monkeypox, and Mycobacterium tuberculosis (TB).
Note: Patients who leave the MICU within 24 hours of randomization are excluded from further study activities. Patients who leave the MICU between 24 and 48 hours post-randomization continue all study activities but will not be included in the primary analysis. Patients who remain in the MICU for at least 48 hours post-randomization will continue all study activities and be included in the primary analysis.