Résumé : Background Total thrombus formation velocity calculated using amplitude parameters obtained at different times could be used to estimate the amplification and the propagation phases observed during coagulation processes, and therefore might be useful to predict postoperative hemostatic products administration in pediatric patients. Methods We retrospectively analyzed data from 49 children <3 months of age who underwent cardiac surgery. Children ≤1 month of age routinely received fresh frozen plasma during bypass while children >1 month of age did not. The EXTEM parameters were used to calculate velocity curves using amplitudes obtained at different times, the area under the curve called total thrombus formation and the maximum rate of thrombus formation. These parameters were compared between children who received fresh frozen plasma and those who did not. Receiver operating characteristics curves were used to define variables that could be used to predict postoperative fresh frozen plasma transfusion. Results Total thrombus formation and maximum rate of thrombus formation significantly increased in children who received fresh frozen plasma compared to those who did not. Both total thrombus formation and maximum rate of thrombus formation have a better specificity to predict postoperative fresh frozen plasma transfusion compared to clotting time or maximal clot firmness. Conclusion Based on this descriptive study, dynamic ROTEM® parameters of total thrombus formation could be used to estimate the amplification and the propagation phases of coagulation in children. These parameters might be used in further well-designed study to predict the need for hemostatic products in children undergoing cardiac surgery with cardiopulmonary bypass.