The unique physiology of children presents challenges to providers in identifying the correct diagnosis, calculating accurate medication doses, and selecting appropriately sized equipment. This study describes the adaptation of an ambulance trigger tool (ATT) to a version for pediatric patients (pATT) to retrospectively identify and classify adverse events in emergency medical service encounters. The pATT identified near misses in 55% of encounters, no-harm incidents in 5.8% of encounters, and harmful incidents in 0.4% of encounters.