Heart Rate Variability and Processed EEG Features as Predictors of Postoperative Outcomes After Cranial Neurosurgery

Inclusion Criteria: * Adult patients (≥18 years) scheduled for elective cranial neurosurgery. * Planned extubation in the PACU after surgery. * Ability to obtain high-quality ECG and EEG recordings intra- and postoperatively (≥60 min expected PACU monitoring). * Written informed consent signed preoperatively. Exclusion Criteria: * Pre-existing severe cardiac arrhythmias (e.g., atrial fibrillation, frequent ectopy) or pacemaker dependence. * Known severe autonomic neuropathy (e.g., advanced diabetes, Parkinson's disease with autonomic failure). * Preoperative conditions associated with abnormal EEG (status epilepticus, uncontrolled seizures, sedative/hypnotic overdose). * Intraoperative or immediate postoperative events necessitating continued mechanical ventilation or ICU admission (e.g., massive bleeding, intraoperative arrest). * Inability to provide informed consent (e.g., cognitive impairment, language barrier without interpreter). * Refusal of informed consent