Effects of Feeding Schedule on the Development of ICU Delirium

This study will investigate if enteric feeding schedules alter the development of delirium in Intensive Care Unit patients who have been placed on mechanical ventilation. Delirium is an altered state of consciousness, which can involve agitation, inattention, and decreased awareness. We will enroll Intensive Care Unit patients who have been placed on a ventilator and are being given tube feedings. We will randomize participants into two groups: one group will receive continuous feedings via feeding tube, and the other group will receive feedings on a schedule to mimic breakfast, lunch, a snack, and dinner. Subjects will be assessed for the development of delirium. Subjects will also be monitored for sleep quality and biomarkers of circadian rhythm.

Patients will need to have at least 48 hours of enteric feedings to be included, and will be stratified by their APACHE IV score. Patients will be randomized into time restricted feeding vs continuous feeding by investigators, with no change in caloric intake nor nutrient content from orders. Patients will be assessed for delirium using the CAM-ICU (Confusion Assessment Method in the Intensive Care Unit) screening tool every twelve hours. At the time of the CAM ICU assessment, as part of the experimental design, the patient's sleep will be monitored by X8 Sleep Profiler device, placed and secured to their forehead, and the Sleep Profiler device will collect information regarding sleep quality as assessed by relative delta power, relative theta power and relative beta power. For the circadian rhythm marker analysis, blood samples (15 mL) will be collected at two time points: a day sample will be collected between 6 and 7 AM and a night sample will be collected between 11 PM and 12 AM. Collection will start approximately 48 hours after ICU admission. The expressions of the genes PER2 and SIRT with their proteins will be analyzed. The samples will also be used to measure serum free cortisol and serum insulin levels.

Patients will be randomly assigned to one of two treatment groups: standard continuous feeding or timed feeding.

Participants will be under sedation. The outcome assessor for delirium (primary outcome) is not blinded. Assessors rating the sleep quality and biomarkers of circadian disruption (secondary outcomes) will be blinded.

Enteric feeding will be given four times per day, approximating breakfast, lunch, a snack, and dinner.

The development of delirium as measured by the CAM-ICU (Confusion Assessment Method for the ICU) protocol. The percent of patients developing delirium will be assessed in each arm. Delirium will be assessed every 12 hours.

The difference between day and night expression of PER2 in serum will be compared between the two arms.

The difference between day and night expression of SIRT in serum will be compared between the two arms.

The difference between day and night concentrations of serum free cortisol will be compared between the two arms.

The difference between day and night concentrations of serum insulin will be compared between the two arms.

Inclusion Criteria: Admitted to the ICU Mechanically ventilated Receiving enteric feedings for at least 48 hours Exclusion Criteria: Pregnancy Previously diagnosed neurocognitive disorders, Alcohol withdrawal and history of alcohol dependence