Excessive postoperative bleeding and outcomes in neonates undergoing cardiopulmonary bypass.

BACKGROUND: Neonates undergoing cardiac surgery are especially prone to the hemostatic alterations of cardiopulmonary bypass (CPB) and are at high risk for post-CPB bleeding. An immature coagulation system, significant hemodilution from the CPB prime, long CPB times at low temperatures, and extensive suture lines increase neonates' susceptibility to bleeding after CPB. In this study, we examined the relationship between excessive bleeding in neonates after CPB and major postoperative adverse events.
METHODS: We retrospectively reviewed the medical records of 169 neonates who underwent complex congenital heart surgery with CPB between January 1, 2010, and December 31, 2011. Perioperative data were collected and analyzed with specific focus on post-CPB bleeding as measured by 24-hour postoperative chest tube output (CTO), post-CPB transfusion requirements, and major postoperative adverse events, including renal dysfunction, dialysis, thrombosis, extracorporeal membrane oxygenation (ECMO), and in-hospital mortality. We used Spearman correlation to determine correlations between multiple perioperative variables and 24-hour CTO and postoperative blood product requirements. Also, we used logistic regression analysis to determine the association between excessive bleeding (defined as 24-hour CTO >75th percentile) and major postoperative adverse events.
RESULTS: Significant correlations were found between 24-hour CTO and postoperative blood product transfusion with weight, Risk Adjustment for Congenital Heart Surgery (RACHS-1) score, CPB time, and lowest temperature. Logistic regression found that excessive bleeding after CPB was an independent predictor of postoperative dialysis (relative risk [RR] 12.0; confidence interval, 1.50-54.69; P = 0.02) and ECMO (RR 9.95; confidence interval, 3.07-28.47; P = 0.0008). RACHS-1 score was a significant predictor of in-hospital mortality (P = 0.03).
CONCLUSIONS: Excessive postoperative bleeding in neonates after CPB is independently associated with increased adverse events, specifically the need for postoperative dialysis and ECMO support. Our findings in neonates are congruent with other recent research that also has found increasing transfusion requirements after pediatric CPB to be independently associated with an increase in major postoperative adverse events. Our results may aid clinicians in anticipating potential adverse events after neonatal bypass and in allocating the resources necessary to manage these events.