Assistant Professor of Pediatrics Washington University School of Medicine St. Louis, Missouri, United States
Abstract:
Background: Fluid overload associates with poor outcomes after neonatal cardiac surgery, but consensus does not exist for the most clinically relevant method of measuring fluid balance (FB). While weight-change based FB (FB-W) is standard in neonatal intensive care units, weighing infants after cardiac surgery may be challenging. We aimed to identify characteristics associated with obtaining weights and to understand how intake/output-based FB (FB-IO) and FB-W compare in the early postoperative period in this population.
Methods: Observational retrospective study of 2235 neonates undergoing cardiac surgery from 22 hospitals comprising the NEonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) database.
Results: 45% (n = 998) of patients were weighed on postoperative day (POD) 2, varying from 2 – 98% among centers. Odds of being weighed were lower for STAT categories 4 and 5 (OR 0.72; 95% CI 0.53-0.98), cardiopulmonary bypass (0.59; 0.42-0.83), delayed sternal closure (0.27; 0.19-0.38), prophylactic peritoneal dialysis use (0.58; 0.34-0.99), and mechanical ventilation on POD 2 (0.23; 0.16-0.33). Correlation between FB-IO and FB-W was weak for every POD 1 – 6 and within the entire cohort (correlation coefficient 0.15; 95% CI 0.12-0.17). FB-W measured higher than paired FB-IO (mean bias 12.5%; 95% CI 11.6%-13.4%) with wide 95% limits of agreement (-15.4%-40.4%).
Conclusions: Weighing neonates early after cardiac surgery is uncommon, with significant practice variation among centers. Patients with increased severity of illness are less likely to be weighed. FB-W and FB-IO have weak correlation, and further study is needed to determine which cumulative FB metric most associates with adverse outcomes.
