Risk factors for the development of significant postoperative bleeding after pediatric cardiac surgery with cardiopulmonary bypass: A nested case-control study

Background: Postoperative bleeding of more than 10% of circulating blood volume (CBV) within the first six hours after a cardiac surgery with cardiopulmonary bypass (CBS) is one of the most frequent complications associated with postoperative morbidity and mortality in children. Objectives: This study aimedto identify specific risk factors for the development of this complication in a subpopulation of Mexican pediatric patients. Methods: A nested case-control study was conducted at a tertiary level pediatric intensive care unit (PICU) of Mexico City. Cases were those children who developed bleeding of more than 10% of circulating blood volume (CBV) within the first six hours after the surgery and controls were all those children who did not presented this complication. Bivariate and logistic regression analyses were performed. A P-value less than 0.05 was considered as statistically significant. Results: Results showed that 33% (n = 21) of included children developed significant bleeding in the first six hours after the cardiac surgery. The main risk factors for developing this complication were the cyanotic congenital heart disease (P < 0.01), bypass time exceeding 90 minutes (P < 0.01), aortic clamping time > 60 minutes (P = 0.01), intraoperative bleeding volume (P = 0.04), and an initial activated clotting time > 140 seconds (P < 0.01). Conclusions: An important proportion of patients developed postoperative significant bleeding. Risk factors identified in the present study could help to identify and close monitor a subgroup of children at high risk for the development of this complication.