Table 1.

Strategies to improve sleep and realign circadian rhythm in the ICU.

Intervention	Mechanism	Evidence
Increase light-dark contrast in the ICU	Loss of exposure to natural light is associated with circadian rhythm disruption that may impact incident delirium and outcomes in critically ill patients	Existing evidence does not support routine light therapy in isolation, the optimal dose, timing, and patient population require further investigation and it may be that light therapy is best deployed as part of a multicomponent strategy
Melatonin therapy	Potential role of melatonin to regulate the circadian distribution of sleep and prevent ICU-acquired delirium	General interest in the potential prophylactic use of melatonin but no current recommendations exist supporting the exogenous administration of melatonin to treat ICU-acquired delirium • Recent meta-analysis indicated that the peri-operative supplementation of melatonin agonists reduced the risk of transitioning into delirium to 37% compared to placebo or no treatment (p = 0.006) (76) • Investigators are currently evaluating the use of melatonin as a prophylactic agent for delirium prevention in the ICU (77)
Mechanical ventilation	Relationship between mechanical ventilation, sleep disturbances, and circadian dysrhythmia not well-understood and likely complex as relate to the use of sedative agents	Attention should be paid to reducing over-assistance with pressure support ventilation and, as available, clinicians should consider modes such as proportional assist-ventilation, and neurally adjust ventilatory assist