Transfusion of Prematures Trial

Long-term outcomes of extremely low birth weight (ELBW) preterm infants, those weighing less than or equal to 1000 g at birth, are poor and pose a major health care burden. Virtually all of these infants are transfused, but at inconsistent hemoglobin (Hgb) thresholds. The investigators propose in TOP to randomize infants less than or equal to 1000 g BW and gestational age at least 22 weeks but less than 29 weeks to receive red blood cell (RBC) transfusions according to one of two strategies of Hgb thresholds, either a high Hgb (liberal transfusion) or a low Hgb (restrictive transfusion) algorithm. It is currently unknown which transfusion strategy is superior. TOP is powered to demonstrate which strategy reduces the primary outcome of death or neurodisability in survivors at 22-26 months. A secondary study entitled "Effect of Blood Transfusion Practices on Cerebral and Somatic Oximetry", also known as the NIRS study, will determine differences in cerebral oxygenation and fractional tissue oxygen extraction with NIRS between high and low hemoglobin threshold groups during red blood cell transfusions. The investigators also propose to determine whether abnormal cerebral NIRS measures are a better predictor of NDI than hemoglobin alone and whether abnormal mesenteric NIRS measures are associated with the development of NEC within the 48 hours following a transfusion. A secondary study entitled "Economic Evaluation Ancillary to the Transfusion of Prematures Randomized Controlled Trial" will determine whether higher transfusion threshold will result in lower total costs to society over the first 22 to 26 corrected months of life and estimate the incremental cost-effectiveness ratio for survival without neurodevelopmental impairment, from the perspective of society, the third-party payer, and the family. Extended follow-up: Subjects will be seen for a follow-up visit at 5-6 years corrected age to assess neurological and functional outcomes at early school age based on neonatal transfusion threshold.