Children have a highly compliant chest wall and atelectasis formation occurs often during pediatric anesthesia. Inhalation induction is commonly performed in pediatric anesthesia but it is still unclear if this can have an effect on the development of atelectasis. Aim of this study is to investigate the impact of inhalation versus intravenous induction on atelectasis formation during anesthesia induction in children. Atelectasis will be evaluated with lung ultrasound before induction and right after induction.

Respiratory complications, among which atelectasis, are a common cause of adverse events in pediatric anesthesia. Lung ultrasound (LUS) examination is a point of care, non-invasive, radiation-free tool with high sensitivity and specificity for the identification of anesthesia-induced atelectasis in children.

Inhalation induction is commonly performed in pediatric anesthesia to avoid pain at venipuncture or to facilitate vein cannulation. This technique has been associated with a higher rate of respiratory adverse events but no study has investigated the role of inhalation or intravenous induction on lung atelectasis development in pediatric anesthesia.

The investigators will perform this study aiming to describe the impact of inhalation versus intravenous induction technique on atelectasis formation during anesthesia induction in children of different ages.

Inclusion Criteria:

• scheduled for elective surgery under general anesthesia
• parental consent

Exclusion Criteria:

• American Society of Anesthesiologists (ASA) physical status III-VI
• neuromuscular disease
• chronic lung disease
• cardiopathy
• thoracic cage malformations
• chronic home ventilation (either invasive or non-invasive)
• positive history of foreign body inhalation
• required immediate life-saving procedures
• lack of parental consent

Children under 18 years of age scheduled for general anesthesia due to surgery.