The objective of this observational study is to evaluate the relationship between ketonemia and emergence delirium in children undergoing general anesthesia. The main questions it aims to answer are:

• Does the level of ketonemia correlate with the risk of emergence delirium in pediatric patients?
• Are there specific perioperative factors that influence this relationship?

If there is a comparison group: Not applicable, as this is an observational study without intervention groups.

Participants will be asked to:

• Provide clinical and demographic information relevant to anesthesia and perioperative care.
• Undergo standard perioperative monitoring, including ketonemia measurement.
• Allow researchers to record anesthesia and recovery outcomes related to emergence delirium.

KETOMED is a multicenter observational study designed to investigate the relationship between ketonemia and emergence delirium in pediatric patients undergoing general anesthesia. The study will prospectively collect perioperative data from children aged 2 to 12 years who are scheduled for elective procedures under general anesthesia.

Blood ketone levels will be measured at standardized time points during the perioperative period, and patients will be monitored for signs of emergence delirium using validated scales (e.g., Pediatric Anesthesia Emergence Delirium scale). In addition to ketonemia, perioperative variables such as type of anesthetic agents, duration of anesthesia, fasting status, and demographic information will be recorded to identify potential confounding factors.

The study aims to characterize the incidence of emergence delirium in relation to ketone levels and to explore whether specific metabolic or perioperative conditions are associated with higher risk. No experimental interventions will be applied; all patients will receive standard clinical care. The study is multicenter, allowing collection of data across diverse pediatric populations and surgical procedures, enhancing generalizability.

Inclusion Criteria:

• Age between 2 and 12 years
• Elective procedure under general anesthesia
• Inpatient or Ambulatory Surgery Center (ASC) setting

Exclusion Criteria:

• Age younger than 2 years or older than 12 years
• Emergency surgery
• Postoperative admission to the Pediatric Intensive Care Unit (PICU)
• Neuropsychiatric disorder
• Carbohydrate metabolism disorder
• Declines to participate voluntarily in the study

The study population includes children aged 2 to 12 years undergoing elective procedures under general anesthesia at participating centers. Participants may be admitted as inpatients or treated in an Ambulatory Surgery Center (ASC). Children with neuropsychiatric disorders, carbohydrate metabolism disorders, those undergoing emergency surgery, or requiring postoperative admission to the Pediatric Intensive Care Unit (PICU) are excluded.