The Effects of Intraoperative Oxygen used at Different Concentrations on Oxidative Stress Markers: A Randomized Prospective Study

Abstract

Aim:In the case of hypoxia, despite the definite benefit of oxygen (O2) administration, there is controversial evidence regarding the risk/benefit balance of high concentration O2 inhalation during surgery as a precaution in those not previously hypoxic. The purpose of this study was to determine the effect of inspiratory O2 (FiO2) administered at different concentrations on oxidative stress during general anesthesia.Methods:This randomized prospective study was conducted from February to May 2021. According to intraoperative FiO2, the patients were divided into two groups: 50% FiO2 (group 1) and 30% FiO2 (group 2). Blood samples taken before preoxygenation and at the end of surgery were used to assess arterial partial O2 pressure (PaO2), total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI).Results:The study was completed with 40 patients. Intragroup plasma TOS, OSI, and PaO2 levels increased significantly at the end of surgery (group 1 p=0.003, 0.003, <0.001, and group 2 p=0.002, 0.044, 0.002) and TAS levels decreased (p<0.001 in both groups) were found. Because of intergroup surgery, TAS, TOS, and PaO2 levels were higher in group 1 than in group 2 (respectively p=0.002, 0.002, <0.001).Conclusion:Since the use of high concentrations of O2 (50%) causes a significant increase in oxidative stress, we think that it is important to use lower concentrations of O2 in the intraoperative period in suitable patients. More research is urgently needed on perioperative O2 therapy.

Keywords

• inspiratory oxygen concentrations
• oxidative stress index
• total antioxidant status
• total oxidant status