LAUSR

Background: We recently developed an EXTrauterine Environment for Neonatal Development (EXTEND) that provides physiologic support for premature lambs. Here, we assess the efficacy of exogenous erythropoietin (EPO) to prevent anemia and transfusions on EXTEND. Materials and Methods: Lambs were cannulated at 0.7 gestation and supported on EXTEND for up to 4 weeks. The lambs were divided into three groups: (1) No EPO, (2) Low EPO (300 U kg–1 per day), and (3) High EPO (800 U kg–1 per day). Daily hematocrit and weekly complete blood count were assessed. Results: The mean percentage change in hematocrit from baseline was significantly different between the groups (No EPO –23.6 ± 7.8% vs. Low EPO –16.6 ± 6.4% vs. High EPO +2.6 ± 6.6%; p = 0.02). This occurred despite a greater median number of blood transfusions in the No EPO group (5 vs. 1 vs. 0; p = 0.02). EPO administration was associated with a higher mean corpuscular volume (MCV; p < 0.01) and reticulocyte count (p = 0.02). The High EPO group was comparable to in utero control fetuses with respect to hematocrit (p = 0.49), MCV (p = 0.24), and reticulocyte count (p = 0.68). Conclusions: EPO (800 U kg–1 per day) prevents anemia, eliminates transfusions, and restores normal red blood cell indices in premature lambs supported by EXTEND.