Neonatal Fellow Brooke Army Medical Center US Army Brooke Army Medical Center San Antonio, Texas, United States
Background: Abnormally high ferritin has been reported during pediatric ECMO, suggestibly attributed to chronic red blood cell transfusion and the potential for iron overload. However, the use of ferritin for diagnosing iron overload is complicated by its roles during hypoxia as an acute phase reactant and supporting erythropoiesis. We aimed to elucidate the role of ferritin during and after ECMO with secondary aims to assess for risk of iron overload and the role of transfusion.
Design/Methods: This prospective observational pilot study included nine pediatric patients from the Children’s Hospital of San Antonio. ECMO candidates with prior exchange transfusion, ECMO run, hemoglobinopathy, liver disease, hemochromatosis, or oncological disorder were excluded. Serial measurements of serum ferritin, iron, erythropoietin (EPO), hepcidin, and interleukin-6 (IL-6) were collected prior to and throughout ECMO. Descriptive statistics, Pearson correlation coefficients, one and two-way ANOVA were utilized to compare targeted biomarkers, cannulation type, and transfusion volumes.
Results: Significant ferritin elevation occurred throughout ECMO treatment (median 459ng/ml, IQR 327, 694). Iron increased 57.6% after cannulation while on ECMO, however normalizing before decannulation. Incidentally, abnormally high EPO levels were observed throughout ECMO (median 44.8mIU/ml, IQR 18.9, 132.6) and rapidly decreased after decannulation. (Table 1) Despite elevation, ferritin poorly correlated with serum iron [r(80) = .05, p=.65] and other markers of iron metabolism. Strong correlations existed between ferritin and IL-6 [r(76) = .48, < .001] and EPO [r(81) =.55, < .001] (Table 2). Despite normalization of IL-6 during ECMO and EPO after ECMO, ferritin remained elevated beyond decannulation in spite of a relatively short half-life of 30 hours. VA cannulation was associated with higher ferritin levels (p <0.001). Serum iron and EPO elevations were associated with higher daily and cumulative transfusion volumes (p<0.01). (Table 3) Conclusion(s): Elevated ferritin during pediatric ECMO appears to correlate predominantly with acute inflammation and is not associated with markers of iron overload. The unexpected significant elevation in EPO during ECMO correlated with ferritin and transfusion volumes. We suggest that ferritin is a poor surrogate for iron overload in ECMO patients, and future investigation into its relationship with EPO and erythropoiesis is warranted.
Authors/Institutions: Zachary Weber, US Army Brooke Army Medical Center, San Antonio, Texas, United States; Ashley E. Sam, US Army Brooke Army Medical Center, Fort Sam Houston, Texas, United States; Cody l. Henderson, Children's Hospital of San Antonio, San Antonio, Texas, United States; Utpal Bhalala, Children's Hospital of San Antonio, San Antonio, Texas, United States; Roger Garcia, Children's Hospital of San Antonio, San Antonio, Texas, United States; Jonathan M. King, Trinity University, San Antonio, Texas, United States; Nicholas R. Carr, University of Utah Health, Sandy, Utah, United States