Comparison of changes in total oxidant and total antioxidant capacities in low-flow and high-flow general anesthesia protocols

Introduction and objective: Oxidative stress is a condition of oxidative damage that occurs when the critical balance between free radical production and antioxidant defense systems is disrupted. Biological targets most exposed to this damage include enzymes, cell membranes and DNA. There are studies showing patient-based advantages of low-flow anesthesia such as respiratory functions and inflammatory response in the postoperative period. However, the number of studies showing its effects on oxidative stress is quite limited. Our study aimed to comparatively evaluate the effects of low-flow anesthesia on total oxidant and total antioxidant balance, as well as its other benefits. Materials and Methods: 72 patients aged 18-65 with physical status of ASA I-II, undergoing general anesthesia were included in the study. The patients were divided into two groups: low flow group (D) and high flow group (Y). Group D received 1 L/min and group Y received 4 L/min fresh gas flow. Vitamin D, albumin, CRP, TAS and TOS values were checked before the operation. BIS monitoring was applied and the same depth of anesthesia was ensured in both groups. Hemodynamic parameters, temperature, ETCO2 and BIS values of the patients were recorded periodically. Albumin, CRP, TAS and TOS were evaluated in the blood samples taken from all patients before the operation, intraoperatively and at the 6th hour after the operation. Results: There was no significant difference between the groups in the preoperative, intraoperative and postoperative TAS, TOS, CRP and albumin values. It was observed that intraoperative TAS values increased significantly in both groups compared to preoperative TAS values (p = 0.006) and postoperative TAS values increased significantly in both groups compared to preoperative TAS values (p = 0.02). It was observed that intraoperative albumin values decreased significantly in both groups compared to preoperative albumin values (p<0.001) and postoperative albumin values decreased significantly in both groups compared to preoperative albumin values (p<0.001). It was observed that CRP increased significantly in the postoperative period in both groups compared to intraoperative (p < 0.001) and preoperative (p < 0.001) values. Conclusion: In our study, it was observed that the effects of low-flow anesthesia on total oxidant and total antioxidant status were similar to high-flow anesthesia. In addition, it was thought that the increase in oxidative stress levels expected due to the application of additional oxygen in general anesthesia applications was suppressed due to the increase in antioxidant levels in our study. Keywords: low flow anesthesia, oxidative stress