Postoperative Hematocrit and Adverse Outcomes in Pediatric Cardiac Surgery Patients: A Cross-Sectional Study from the Society of Thoracic Surgeons and Congenital Cardiac Anesthesia Society Database Collaboration

BACKGROUND: We sought to examine potential associations between pediatric postcardiac surgical hematocrit values and postoperative complications or mortality. METHODS: A retrospective, cross-sectional study from the Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) and Congenital Cardiac Anesthesia Society Database Module (2014-2019) was completed. Multivariable logistic regression models, adjusting for covariates in the STS-CHSD mortality risk model, were used to assess the relationship between postoperative hematocrit and the primary outcomes of operative mortality or any major complication. Hematocrit was assessed as a continuous variable using linear splines to account for nonlinear relationships with outcomes. Operations after which the oxygen saturation is typically observed to be <92% were classified as cyanotic and ≥92% as acyanotic. RESULTS: In total, 27,462 index operations were included, with 4909 (17.9%) being cyanotic and 22,553 (82.1%) acyanotic. For cyanotic patients, each 5% incremental increase in hematocrit over 42% was associated with a 1.31-fold (95% confidence interval [CI], 1.10-1.55; P =.003) increase in the odds of operative mortality and a 1.22-fold (95% CI, 1.10-1.36; P <.001) increase in the odds of a major complication. For acyanotic patients, each 5% incremental increase in hematocrit >38% was associated with a 1.45-fold (95% CI, 1.28-1.65; P <.001) increase in the odds of operative mortality and a 1.21-fold (95% CI, 1.14-1.29; P <.001) increase in the odds of a major complication. CONCLUSIONS: High hematocrit on arrival to the intensive care unit (ICU) is associated with increased operative mortality and major complications in pediatric patients following cardiac surgery.