We conducted a retrospective cross-sectional study of an urban EMS system and an urban ED. We studied 141 consecutive patients (47 children and 94 adults, matched by date of presentation) in cardiopulmonary arrest who were transported to the pediatric and adult EDs by ALS-trained prehospital providers (paramedics) between January 1992 and July 1995. We reviewed ambulance trip reports and ED records to determine when and which interventions were performed in the prehospital setting