Brain-monitored anesthesia may cut complications in elderly surgery patients

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: Aged ≥65 years, regardless of gender; Scheduled for elective abdominal surgery with general anesthesia duration (from anesthesia induction to surgery completion) ≥ 2 hours; American Society of Anesthesiologists (ASA) physical status classification of I-III; Body mass index (BMI) of 18.5-29.9 kg/m²; Postoperative hospital stay expected to exceed 72 hours; Compliant with ethical standards, with voluntary signed informed consent. Exclusion Criteria: Severe cardiovascular diseases, including: History of myocardial infarction within the past 6 months; Bradycardia (resting heart rate \<50 beats/min); Uncontrolled hypertension (sitting systolic blood pressure ≥160 mmHg and/or diastolic blood pressure ≥100 mmHg during screening); Sitting systolic blood pressure ≤90 mmHg during screening; History of severe valvular heart disease; Uncontrolled severe respiratory infections: e.g., severe pneumonia, acute bronchitis. Abnormal liver function: Aspartate Aminotransferase (AST) and/or Alanine Aminotransferase (ALT) ≥2.5×Upper Limit of Normal (ULN), Total Bilirubin (TBIL) ≥1.5×Upper Limit of Normal (ULN); Abnormal renal function: urea or blood urea nitrogen (BUN) ≥1.5×Upper Limit of Normal (ULN), serum creatinine \>Upper Limit of Normal (ULN); Admission hemoglobin A1c (HbA1c) ≥6.5% or ≥2 fasting blood glucose measurements ≥180 mg/dl (10 mmol/L) and/or random blood glucose ≥200 mg/dL (≈11.1 mmol/L); Preoperative anemia (Hemoglobin \[Hb\] ≤90 g/L), thrombocytopenia (Platelet \[PLT\] ≤80×10⁹/L), hypoproteinemia (Albumin \[Alb\] ≤30 g/L); History of drug abuse and/or alcoholism within the past 2 years (alcoholism defined as daily average alcohol consumption \>2 units, where 1 unit = 360 mL beer or 45 mL 40% ethanol liquor or 150 mL wine); Neurological diseases (e.g., stroke within 6 months, Alzheimer's disease, Parkinson's disease, mental disease, myasthenia gravis) or psychiatric disorders (e.g., schizophrenia, mania, bipolar disorder, delirium), history of long-term use of neuropsychiatric medications, or cognitive impairment; Allergy or contraindication to study medications; Patients refusing or unable to cooperate with the study; Scheduled for pancreatic surgery; Other conditions deemed inappropriate for participation by the investigator.