Critical Events in Anaesthetised Kids Undergoing Tracheal Intubation (CRICKET)-study protocol for an international multicentre prospective observational study.

Background: Critical Events in Anaesthetised Kids undergoing Tracheal Intubation (CRICKET) is a prospective, international multicentre observational study with the objective of capturing, assessing, and analysing critical events associated with tracheal intubation in children. Methods: CRICKET involves paediatric patients aged 0-16 yr, requiring tracheal intubation, performed by the anaesthesia team for procedures or interventions requiring general anaesthesia, either planned or unplanned. Patient characteristics and airway management techniques are recorded using a dedicated electronic case report form. If one or more critical events associated with airway management occur, a second, more detailed questionnaire will be completed for the follow-up until the patient is discharged or up to a maximum of 30 days. We aim to include 105 000 patients from participating centres disseminated worldwide. Every participating centre collects data over a consecutive observational period of 3 months. The primary outcome is the incidence of critical events associated with tracheal intubation in children. Results: The CRICKET study started in January 2024 and is currently ongoing. By May 2025, around 25 000 patients were entered into the database, with an estimated 50 000 patients by the end of 2025. Because of the observational nature of the study and the extensive international involvement and effort, continuing the study or analysing the existing data will depend on available resources and exact incidence of critical events. Funding: This work was supported by the Italian Ministry of Health (Ricerca Corrente 2025). Clinical trial registration: ClinicalTrials.gov (NCT05804188).