Sleep disturbances should not be overlooked in the management of critically ill patients. Critically ill patients frequently encounter sleep deprivation and circadian rhythm disruptions due to various factors, such as underlying diseases, environmental influences, frequent medical interventions, immobility, and delirium. This manuscript aims to review the research progress regarding the mechanisms and impact of sleep disturbances in critically ill patients, thereby enhancing sleep quality and stabilizing circadian rhythms. The synaptic homeostasis hypothesis, neural synchronization and desynchronization processes, memory consolidation mechanisms, metabolic and energy dynamics, immune system modulation, organ functional interactions, disruption of the light-dark cycle, and pharmacological agents utilized are all implicated in the pathophysiology of sleep disorders and circadian rhythm disturbances of critically ill patients. These conditions can exacerbate organ dysfunction, delay recovery, prolong hospital stays, and negatively impact both short-term and long-term outcomes. Understanding the pathogenesis of sleep disorders in critically ill patients effectively is of paramount importance.
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