Sleep and Circadian Rhythm Intervention in ICU

Circadian rhythm intervention is a growing research field in critical care. The ICU environment is complTex, and circadian disruption is influenced by many risk factors. Studies have shown that single interventions have limited effects on improving clinical outcomes. Therefore, a multicomponent approach targeting multiple risk factors may be more effective in improving sleep and circadian regulation in ICU patients. Previous studies have often focused only on subjective sleep quality and ignored objective circadian measures such as hormone secretion rhythms and sleep-wake cycles. This limits the reliability of their findings.

This study develops a multicomponent sleep and circadian rhythm intervention that includes sound and light control, optimization of nursing activities, promotion of daytime activity, and cognitive stimulation. Subjective and objective measures will be used to evaluate sleep and circadian rhythm. The study is a non-randomized controlled trial designed to test the feasibility of this intervention and to explore its preliminary effects in ICU patients.

• Sound and Light Optimization (Other): Patients receive eye masks and earplugs at night; Overhead lights are turned off at 10:00 p.m. and replaced with dim bedside lights until 7:00 a.m; Curtains are opened as early as possible after 7:00 a.m; Device alarms and telephones are set to low volume during the night and restored to normal levels after 7:00 a.m; Staff members switch their phones to silent or vibration mode and keep conversations at low volume; A noise meter is installed to remind staff to maintain a quiet environment.
• Night-time Patient Care Activities (Other): Nighttime care activities will be reorganized to reduce patient disturbances. Non-urgent procedures will be postponed to daytime hours, while emergency interventions will proceed as needed.
• Enhanced Daytime Mobility (Other): Additional early mobilization sessions led by a physiotherapist will be conducted once daily between 10:00 and 16:00 during ICU stay, including out-of-bed and limb exercises. The intensity will be individualized according to the patient's clinical condition.
• Cognitive Stimulation (Other): Patients will receive daily orientation to time and environment to reinforce temporal and spatial awareness. Daytime interaction with patients will be encouraged to promote alertness and assess comfort and sleep quality. For nonverbal patients, visual aids such as picture cards or writing boards will be provided to facilitate communication. Simple entertainment tools (e.g., radio, rehabilitation ball) will be offered to promote wakefulness during the daytime.

Primary outcomes

• Recruitment rate [From enrollment to Day 3]: Percentage of eligible patients who provide informed consent and enroll in the study
• Retention rate through Day 3 [From enrollment to Day 3]: Percentage of enrolled participants who remain in the study through Day 3
• Data completeness [From enrollment to Day 3]: Percentage of required study data that are missing
• Intervention adherence [From enrollment to Day 3]: Percentage of participants allocated to the intervention group who receive the complete intervention as planned up to ICU discharge

Secondary outcomes

• Melatonin concentration [Blood samples will be collected at 03:00, 15:00 in the first three days after ICU admission]: Serum melatonin concentrations will be measured to characterize melatonin secretion and its temporal pattern. Melatonin concentrations will be quantified using liquid chromatography-mass spectrometry (LC-MS).
• Cortisol concentration [Blood samples will be collected at 03:00 and 15:00 in the first three days after ICU admission]: Serum cortisol concentrations will be measured to characterize cortisol secretion and its temporal pattern.
• Richards-Campbell Sleep Questionnaire score [Each mornining the first three days after ICU admission]: Subjective sleep quality will be assessed using the Richards-Campbell Sleep Questionnaire (RCSQ). The RCSQ evaluates perceived nighttime sleep, including sleep depth, sleep latency, awakenings, return to sleep, and overall sleep quality. The total score ranges from 0 to 100, with higher scores indicating better perceived sleep quality.
• Total sleep time measured by polysomnography [During the second night following ICU admission.]: Overnight polysomnography (PSG) will be performed to objectively assess sleep. Total sleep time, expressed in minutes, will be derived from overnight polysomnography.
• N3 sleep stage percentage [During the second night following ICU admission.]: Overnight polysomnography (PSG) will be performed to objectively assess sleep. N3 sleep stage percentage will be derived from overnight polysomnography.
• REM sleep stage percentage [During the second night following ICU admission]: Overnight polysomnography (PSG) will be performed to objectively assess sleep.REM sleep stage percentage, will be derived from overnight polysomnography.
• Mean activity level measured by wrist actigraphy [During Days 1 and 2 of the ICU stay.]: Physical activity will be continuously assessed using a wrist-worn actigraphy device. Mean activity level will be calculated separately for daytime and nighttime periods.
• Rate of non-zero activity measured by wrist actigraphy [During Days 1 and 2 of the ICU stay.]: The rate of non-zero activity will be assessed using a wrist-worn actigraphy device and defined as the percentage of valid epochs with activity counts greater than zero, calculated separately for daytime and nighttime periods.
• Mean non-zero activity intensity measured by wrist actigraphy [During Days 1 and 2 of the ICU stay.]: Mean non-zero activity intensity will be assessed using a wrist-worn actigraphy device and expressed as the mean activity counts among epochs with activity counts greater than zero, calculated separately for daytime and nighttime periods.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Adult patients aged 18 years or older.
* Patients expected to stay in the surgical ICU for at least 2 nights.
* Patients directly admitted to the surgical ICU postoperatively.
* Patients with a Richmond Agitation-Sedation Scale (RASS) score between -1 and 1 upon ICU admission.

Exclusion Criteria:

* Patients who have delirium or dementia at ICU admission.
* Patients who are unable to communicate effectively.
* Patients with hearing or vision impairment.
* Patients with lower-limb deep vein thrombosis, fractures, or multiple severe injuries that contraindicate early mobilization.
* Patients after cranial or otolaryngological surgery who cannot use earplugs or eye masks.
* Patients with a history of dementia, psychiatric disorders, or structural neurological diseases.
* Pregnant or breastfeeding patients.
* Patients in a terminal or end-of-life condition.