METHODS A prospective blinded, randomized controlled study compared the effect of a perioperative infusion of aprotinin versus placebo during long segment spinal fusions in children. OBJECTIVE To determine whether aprotinin decreases blood loss and transfusion requirements in pediatric patients with spinal deformities undergoing posterior spinal fusions of seven or greater segments. BACKGROUND Blood loss is a major cause of morbidity during long segment spinal fusion. Several preoperative and intraoperative techniques are currently used to reduce blood loss and transfusion requirements. Aprotinin, an antifibrinolytic and anti-inflammatory agent, has been used to decrease blood loss in cardiac surgical patients. We designed a prospective, randomized, and blinded controlled study to evaluate aprotinin's efficacy in reducing bleeding during pediatric spine surgery. METHODS After obtaining informed written consent, we studied 44 children and adolescents who were anticipated to be at higher risk for major blood loss during posterior spinal fusion. Children were randomly assigned to receive high dose aprotinin or placebo infusion during the perioperative period. Patients were assessed for blood loss, transfusion requirements, days in the intensive care unit, and days in hospital. RESULTS Demographics in the two groups of patients were similar. The study demonstrated a significant reduction in estimated blood loss (aprotinin 545 cc, placebo 930 cc) and transfusion requirements (aprotinin 1.1 U, placebo 2.2 U). The duration of intensive care unit admission was similar in the two groups, as was the time until discharge. CONCLUSIONS This randomized, blinded study suggests that aprotinin significantly decreased blood loss and transfusion requirements in pediatric and adolescent scoliosis surgical patients at increased risk for intraoperative bleeding.