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.

Inclusion Criteria:

• Children aged 0 to 35 months
• Scheduled for elective surgery under general anesthesia
• Planned airway management with a laryngeal mask airway
• Ability to perform intraoperative ultrasonographic subglottic airway measurements
• Written informed consent obtained from a parent or legal guardian

Exclusion Criteria:

• Known congenital or acquired airway anomalies
• Craniofacial anomalies
• Emergency surgical procedures
• Planned tracheal intubation instead of laryngeal mask airway
• Inability to obtain adequate ultrasonographic subglottic airway measurements

The study population consists of children under three years of age scheduled for elective surgery under general anesthesia. All participants undergo planned airway management with a laryngeal mask airway and intraoperative ultrasonographic assessment of the subglottic airway as part of routine clinical care. Written informed consent is obtained from a parent or legal guardian prior to participation.