Fluid Accumulation After Neonatal Congenital Cardiac Surgery; Clinical Implications and Outcomes

Abstract

BACKGROUND To determine the association between fluid balance metrics and mortality and other postoperative outcomes after neonatal cardiac surgery in a contemporary multi-center cohort. METHODS Observational cohort study across 22 hospitals in neonates (≤30 days) undergoing cardiac surgery. We explored overall % fluid overload, postoperative day 1 % fluid overload, peak % fluid overload, and time to first negative daily fluid balance. The primary outcome was in-hospital mortality. Secondary outcomes included postoperative duration of mechanical ventilation, and intensive care unit (ICU) and hospital length of stay. Multivariable logistic or negative binomial regression was used to determine independent associations between fluid overload variables and each outcome. RESULTS The cohort included 2223 patients. In-hospital mortality was 3.9% (n=87). Overall median peak % fluid overload was 4.9%, (interquartile range 0.4-10.5%). Peak % fluid overload and postoperative day 1 % fluid overload were not associated with primary or secondary outcomes. Hospital resource utilization increased on each successive day of not achieving a first negative daily fluid balance and was characterized by longer duration of mechanical ventilation (incidence rate ratio 1.11, 95% confidence interval 1.08-1.14, ICU length of stay (incidence rate ratio 1.08, 95% confidence interval 1.03-1.12), and hospital length of stay (incidence rate ratio 1.09, 95% confidence interval 1.05-1.13). CONCLUSIONS Time to first negative daily fluid balance, but not % fluid overload is associated with improved postoperative outcomes in neonates after cardiac surgery. Specific treatments to achieve an early negative fluid balance may decrease postoperative care durations.