This study aims to better understand postoperative respiratory adverse events that may occur in some children under three years of age undergoing airway management during surgery. As part of the study, ultrasonographic measurements of a portion of the upper airway will be performed during surgery using a non-invasive ultrasound device. These measurements will be evaluated in relation to perioperative respiratory outcomes. The results of this study may contribute to improved understanding of airway-related factors associated with postoperative respiratory safety in young children.