The Effect of Minimal Flow Anesthesia on Oxidative and Neuroendocrine Stress Response

Patients under general anesthesia who are unconscious and have stopped spontaneous breathing are actively ventilated with anesthesia machines, ensuring the anesthesia gas reaches the lungs and then the bloodstream. Not all the gas reaching the lungs during respiration is used; a small portion is absorbed by the body, and most of it is expelled during exhalation. After eliminating the carbon dioxide in the expired gas, it is more suitable to re-breathe the remaining gas. The portion taken by the patient needs to be provided for the next breath, and this added gas is called "fresh gas flow." Today, low flow anesthesia is defined when the fresh gas flow rate is 0.5-1 L/min, minimal flow anesthesia when it is 0.25-0.5 L/min, and metabolic flow anesthesia when it is 0.25 L/min. Our study will evaluate the effects of minimal flow anesthesia, which is widely used today due to its advantages, on oxidative stress and neuroendocrine stress response