Mini-dose Dexmedetomidine-Esketamine Supplemented Analgesia in Patients at High-risk of OSA

Inclusion criteria: 1. Aged ≥18 years but ≤80 years; 2. Preoperative diagnosis of OSA, or judged to be at moderate-to-high risk of OSA according to the STOP-Bang Questionnaire; 3. Scheduled to undergo thoracoscopic or laparoscopic surgery under general anesthesia, with an expected surgical duration of ≥1 hours, and required patient-controlled intravenous analgesia (PCIA) after surgery. Exclusion criteria: 1. Diagnosed as central sleep apnea syndrome; 2. Previous history of schizophrenia, epilepsy, Parkinson disease, or myasthenia gravis. 3. History of schizophrenia, or having antipsychotic drugs (including antidepressants or anxiolytics); 4. Inability to communicate in the preoperative period because of coma, profound dementia, or deafness; 5. History of drug or alcohol dependence, or sedative or hypnotic therapy within 1 month before surgery; 6. Contraindications to ketamine (such as hyperthyroidism, pheochromocytoma, or glaucoma); 7. Sick sinus syndrome, severe sinus bradycardia (\<50 beats per minute), or second-degree or above atrioventricular block without pacemaker; 8. Contraindications to high-flow nasal cannula therapy (such as mediastinal emphysema, shock or hypotension, cerebrospinal fluid leakage, nasosinusitis, otitis media, or deviation of nasal septum); 9. Severe hepatic dysfunction (Child-Pugh class C), severe renal dysfunction (requirement of renal replacement therapy), severe heart dysfunction (preoperative New York Heart Association functional classification ≥3 or left ventricular ejection fraction \<30%), or ASA classification IV or above; 10. Expected intensive care unit (ICU) admission with tracheal intubation after surgery; 11. Other conditions that are considered unsuitable for study participation.