DeliKet (Substudy of KetoNiFast Study ID 22-1398_1)

Postoperative delirium is a common problem of the critically ill patient and associated with an increased mortality. Intermittent fasting and ketogenesis have been shown to be beneficial for maintaining a circadian rhythm and initiating anti-inflammatory repair mechanisms which could potentially be neuroprotective. However, so far there is little data if cyclic enteral feeding with ketogenic nighttime fasting might be beneficial for reducing the rate of postoperative delirium. The study hypothesis is that equicaloric cyclic enteral feeding (12 hrs) during daytime with ketogenic fasting and exogenous ketone supplementation at nighttime compared to continuous standard enteral nutrition (24 hours) decreases the incidence of postoperative delirium in critically ill patients.