Prospective cohort study on characteristics, associated factors and short-term prognosis of sleep and circadian rhythm in intensive care unit: protocol for the SYNC study.

introductionAcute sleep and circadian rhythm (SCR) disruption can lead to a range of negative physical and mental consequences, such as depression, delirium, respiratory dysfunction and increased mortality. In the intensive care unit (ICU), the unique environment can exacerbate disruptions in SCR. Few studies have identified the characteristics of SCR in the ICU, and the roles of patient characteristics, illness and medical interventions in ICU SCR remain unclear. A single-centre prospective cohort study, called SYNC study (Sleep and circadian rhYthm in iNtensive Care unit), will be conducted to explore the characteristics and associated factors of SCR and investigate the short-term prognosis among patients in the surgical ICU. METHODS AND ANALYSIS: Patients from a surgical ICU at a tertiary teaching hospital will be enrolled. SCR will be assessed by both objective and subjective indicators, including melatonin secretion rhythm, activity rhythm, sleep pattern and perceived sleep quality. Data on eight potential factors that influence SCR, including light exposure, noise level, pain level, nighttime disturbances, mechanical ventilation, sedative and analgesic use, meal pattern and restraints, will be collected. These data will be gathered in the first 3 days after ICU admission. Short-term prognostic indicators, including anxiety, depression, cognitive function, insomnia, activities of daily living, ICU stay, hospital stay and hospital mortality will be collected during the hospital stay and at 1 month after discharge. ETHICS AND DISSEMINATION: The study has been approved by the Ethics Committee of Zhongshan Hospital, Fudan University (B2024-076R). The results of this study will be published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT06346613.