Nucleated red blood cells as a biomarker for mortality in infants and neonates requiring veno-arterial extracorporeal membrane oxygenation for cardiac disease

Introduction: Nucleated red blood cells (NRBC) are rare in the peripheral circulation of healthy individuals and their presence have been associated with mortality in adults and very low birth weight newborns, however, its value as a biomarker for mortality in infants requiring veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) has yet to be studied. We sought to determine if NRBC can serve as a biomarker for ECMO mortality and inpatient mortality in infants requiring V-A ECMO. Methods: A single-center retrospective chart review analyzing infants <1 year of age requiring VA ECMO due to myocardial dysfunction or post-cardiotomy between January 1, 2011 to June 30, 2020. Results: One hundred two patients required VA ECMO. Sixty-five patients required ECMO post-cardiotomy, 19 for perioperative deterioration, and 18 for myocardial dysfunction. Fifty-one patients (50%) died (21 died on ECMO, 30 died post-ECMO decannulation). Multivariable analysis found Age <60 days (OR 13.0, 95% CI 1.9-89.6, p = 0.009), NRBC increase by >50% post-ECMO decannulation (OR 17.1, 95% CI 3.1-95.1, p = 0.001), Single Ventricle (OR 9.0, 95% CI 1.7-47.7, p = 0.01), and lactate at ECMO decannulation (OR 3.0, 95% CI 1.3-7.1, p = 0.011) to be independently associated with inpatient mortality. ROC curves evaluating NRBC pre-ECMO decannulation as a biomarker for mortality on ECMO (AUC 0.80, 95% CI 0.68-0.92, p <= 0.001) and post-ECMO decannulation (AUC 0.75, 95% CI 0.65-0.84, p <= 0.001) show NRBC to be an accurate biomarker for mortality. Conclusions: Greater than 50% increase in NRBC post-ECMO decannulation is associated with inpatient mortality. NRBC value pre-ECMO decannulation may be a useful biomarker for mortality while on ECMO and post-decannulation.