Cerebral Oxymeter and End Tidal Carbondioxide Values Under Surgical Drapes With and Without Past COVID-19 Infection

After the patients who meet the specified criteria are informed about the study, the volunteers who agreed to participate and signed informed consent will be included in the study. After all volunteers are taken to the operation room, vascular access will be established, electrocardiography, pulse oximetry, non-invasive blood pressure, end-tidal carbon dioxide and cerebral oximetry (with the neck in the supine position in the neutral position and 2 probes placed on the forehead) are monitored without any medication (Figure 1). The optic nerve sheath diameter will be measured by the ultrasonography device in the inventory of the Department of Anesthesiology and Reanimation by the researchers, basal heart rate (CTA), peripheral oxygen saturation (SpO2), systolic (SBP) and diastolic blood pressure (DBP), end- Tidal carbon dioxide (ETCO2), cerebral oxygen saturation (SO) values will be recorded. All measurements except optic nerve sheath diameter will be recorded and repeated at 5 minute intervals throughout the operation. During this time, no drugs or invasive methods will be used. During the operation, the volunteers in both groups will be randomly divided into 2 subgroups and 2L/min and 4 L/min nasal oxygen support will be provided. At the end of the operation, the ultrasonographic optic nerve sheath diameter measurement will be repeated immediately after the dressing is removed.