Validation of a definition of excessive postoperative bleeding in infants undergoing cardiac surgery with cardiopulmonary bypass.

Objective: To derive and validate an objective definition of postoperative bleeding in neonates and infants undergoing cardiac surgery with cardiopulmonary bypass.

Methods: Using a retrospective cohort of 124 infants and neonates, we included published bleeding definitions and cumulative chest tube output over different postoperative periods (eg, 2, 12, or 24 hours after intensive care unit admission) in a classification and regression tree model to determine chest tube output volumes that were associated with red blood cell transfusions and surgical re-exploration for bleeding in the first 24 hours after intensive care unit admission. After the definition of excessive bleeding was determined, it was validated via a prospective cohort of 77 infants and neonates.