Predictive Efficacy of Ratio of Median Frequency to Spectral Edge Frequency Used in the Depth of Anaesthesia Monitoring on Post-operative Cognitive Functions

Inclusion Criteria: Adult patients (aged over 18 years), Patients undergoing elective surgeries, Patients consenting to participate in the study. Exclusion Criteria: Pediatric patients (aged under 18 years), Patients undergoing emergency surgeries, Patients requiring or anticipated to require postoperative intensive care for more than one day, Patients undergoing cardiac surgeries, Patients undergoing intracranial surgeries, Patients are undergoing endoscopic sinus or brain surgeries, Patients with pacemakers or implantable cardioverter-defibrillators (ICDs), Patients diagnosed with dementia (including Alzheimer's disease, Lewy body dementia, etc.), Patients with chronic opioid or benzodiazepine use, Patients with contraindications to Propofol, Remifentanil, or Fentanyl, Pregnant or breastfeeding women, Patients are not willing to participate in the study.