Inclusion Criteria:  patients aged between 18-60 years, ASA I-II risk class with a minimum operative time of 1.5 hour(s) for whom septoplasty operation under elective conditions  Exclusion Criteria:  metabolic, endocrine, hepatic, cardiac, or renal diseases, malignancies and who used a drug with antioxidant properties such as vitamin E-C acetylcysteine in the last 48 hours, patients requiring intraoperative 100% O2 inhalation