Major Noncardiac Surgery

This prospective observational study aims to develop and evaluate predictive models for postoperative complications in patients aged 65 years or older scheduled for elective major surgery. The investigators will recruit 520 eligible patients visiting the preoperative assessment clinic. The study involves the prospective collection of comprehensive preoperative data using specific validated tools: * Physical Activity: Assessed using the Saltin-Grimby Physical Activity Scale (SGPAS) to categorize physical activity intensity. * Nutritional Risk: Screened using the Nutritional Risk Screening 2002 (NRS-2002) tool. * Psychological Status: Evaluated for anxiety and depression using the Hospital Anxiety and Depression Scale (HADS). * Body Composition: Measured using a portable bioelectrical impedance analysis (BIA) device (BWA2.0S, InBody) to assess muscle mass, body fat/water, and phase angle. * Physical Function: Assessed via the short physical performance battery (SPPB) using electronic measurement devices (AndanteFit, DYPHI) to calculate frailty index and physical age. The primary endpoint is the occurrence and severity of postoperative complications within 30 days, evaluated using both the Clavien-Dindo Classification and the Comprehensive Complication Index (CCI). Using the collected dataset, the investigators will develop prediction models using both classical regression analysis and machine learning algorithms to compare their predictive performance.

Patients over the age of 65 years are at increased risk for developing delirium after noncardiac surgeries, resulting in increased morbidity and mortality. The prevention of postoperative delirium has been classified as a public health priority. However, so far data regarding possible intraoperative interventions to reduce the incidence of postoperative delirium is very scarce. Due to the more rapid wash-in and wash-out times of desflurane as compared to sevoflurane or propofol it seems reasonable that desflurane might be beneficial for the prevention of postoperative delirium. Therefore, we evaluate the effect of maintenance of anesthesia using desflurane, sevoflurane or propofol on postoperative delirium in elderly patients undergoing moderate- to high-risk major noncardiac surgery.

Sleep disturbances are common early after major surgery, and are associated with delayed recovery. A previous study showed that dexmedetomidine-esketamine combination as a supplement to patient-controlled intravenous analgesia improved postoperative analgesia and subjective sleep quality in patients after scoliosis correction surgery. The purpose of this trial is to test the hypothesis that dexmedetomidine-esketamine combination used as a supplement during general anesthesia and postoperative intravenous analgesia may reduce sleep disturbances in adult after major noncardiac surgery.