The Effective Blood Concentration of Ciprofol

Inclusion Criteria: * Patients aged 18-65 years * Scheduled for elective thyroidectomy * ASA physical status classification I-II * Willing to participate and providing written informed consent Exclusion Criteria: * Recent use of sedatives or opioid analgesics * Severe hepatic or renal dysfunction defined as:Child-Pugh class C (score ≥10), Creatinine clearance \<35 mL/min ,Requiring preoperative dialysis * Significant cardiovascular comorbidities * Body mass index ≥35 kg/m² or \<18.5 kg/m² * Known hypersensitivity or adverse reactions to propofol/ciprofol * Neuropsychiatric disorders including:Alzheimer's disease,History of cerebrovascular events,Traumatic brain injury,Space-occupying brain lesions,Other significant neurological deficits