Objective: This study was designed to evaluate the accuracy of Pleth Variability Index (PVI), Perfusion Index (PI) and Regional Oxygen Saturation (rSO2) in both ventilation modes in patients undergoing septorhinoplasty operation under general anaesthesia. Materials and Methods: After anaesthesia induction, ventilation was provided with volume control for 20 minutes. Heart Rate (HR), PI, PVI, Oxygen Saturation (SpO2), Non-Invasive Blood Pressure (NIBP) and rSO2 values were recorded every 5 minutes. At the 20th minute of the surgical procedure, the ventilation mode was set as the pressure-controlled mode. After switching to pressure-controlled mode, HR, PI, PVI, SpO2, NIBP and rSO2 values were recorded every 5 minutes for 20 minutes.

Inclusion Criteria:

• patients with American Society of Anesthesiologists (ASA) score I-III between the ages of 18-80 were included

Exclusion Criteria:

• Those patients with any Liver and/or Kidney Failure
• obese patients (Body Mass Index (BMI) 30 and above)
• trauma patients
• cancer patients
• ASA IV patients
• those patients with emergency surgery
• cardiac arrhythmia
• implanted pacemakers
• those with a history of chronic pain

50 patients with American Society of Anesthesiologists (ASA) score I-III between the ages of 18-80 were undergoing septoplasty surgery