Little known and less understood: the benefits of a lower hematocrit (~40%) in reconstituted blood for double volume exchange transfusion.

A double volume exchange transfusion (DVET) is an important, if infrequently performed, intervention to acutely lessen the total serum bilirubin (TSB) and reduce the extravascular CNS bilirubin exposure when neonatal hyperbilirubinemia poses a neurotoxicity risk. The current analysis based on the seminal works of Valaes, and Sproul and Smith, predicts that a DVET blood product of lower hematocrit (~40%) via its greater plasma volume and corresponding higher albumin content optimizes the benefits of an DVET in several ways. First, by augmenting bilirubin clearance from the extravascular space and thereby further reducing the CNS bilirubin exposure, second, by favorably positioning the intravascular albumin-bilirubin binding capacity at DVET completion to accommodate additional bilirubin equilibration and rebound hyperbilirubinemia post-exchange, and third by correcting anemia if present.