Fig. 1

Study schema illustrating our specific aims, projected infant enrollment, and methodologic approach. Our prospective, observational cohort investigation will determine the associations of prolonged irradiation time (pIST) and metabolic changes of transfused RBCs to alterations in mesenteric oxygenation that may increase the risk for NEC in preterm infants weighing ≤1250 g. In addition, we will explore the implications of severe anemia (hemoglobin ≤8 g/dL) when infants are most vulnerable to NEC development, approximately 29–34 weeks’ gestation. Abbreviations: NIRS, near-infrared spectroscopy, RBC, red blood cell; PMA, post menstrual age; NEC, necrotizing enterocolitis; mesSO2, mesenteric regional oxygen saturation