Sedation With Dexmedetomidine-esketamine Combination and Delirium in ICU Patients

Patients in the intensive care unit (ICU) often develop anxiety and agitation, sleep disturbances, and delirium. Delirium occurrence is associated with worse early and long-term outcomes. Dexmedetomidine and ketamine are recommended for sedation and analgesia in postoperative ICU patients, but each may induce side effects. The sedative effects of dexmedetomidine can help mitigate the neuropsychiatric side effects of esketamine. Recent studies showed that dexmedetomidine-esketamine combination improved analgesia and sleep quality without increasing side effects. This trial is designed to test the hypothesis that dexmedetomidine-esketamine combination for sedation and analgesia in postoperative ICU patients may reduce delirium.

Inclusion Criteria: 1. Aged 60 years or older; 2. Admitted to the intensive care unit (ICU) after surgery; 3. Expected to stay in the ICU for at least one night. Exclusion Criteria: 1. History of schizophrenia, epilepsy, Parkinson's disease, or myasthenia gravis; 2. Presence of preoperative delirium, or inability to communicate due to coma, severe dementia, or language barrier; 3. Previously diagnosed obstructive sleep apnea, judged to be at high risk of moderate-to-severe obstructive sleep apnea according to the STOP-Bang questionnaire, or have a body mass index \>30 kg/m²; 4. Preoperative left ventricular ejection fraction \