Isovolemic hemodilution red cell exchange and blood use in children and young adults with sickle cell disease

Chronic red blood cell (RBC) transfusions are essential for sickle cell disease (SCD) management, but the cumulative demand for donor RBCs strains blood supplies and increases risks of iron overload and alloimmunization. Isovolemic hemodilution red cell exchange (IHD-RCE) is a 2-step procedure designed to reduce RBC requirements, but its effectiveness remains unclear, particularly in pediatric patients. We conducted a retrospective cohort study of 45 children and young adults with SCD, each receiving standard RCE followed by IHD-RCE, comparing within-patient RBC use between RCE types. Inclusion required ≥6 consecutive standard RCEs and ≥6 consecutive IHD-RCEs within a year of each other. Across 2667 RCE procedures, paired analyses demonstrated both standard and IHD-RCE required a median of 1.2 RBC units per liter of total blood volume (TBV; P = .3017). Adjusted analyses showed that IHD-RCE increased RBC requirements for patients with a TBV of ≤3500 mL. Although not statistically significant, IHD-RCE offered modest RBC savings in patients with a TBV of >4500 mL. Stratified analysis showed IHD-RCE related savings only for patients requiring >4 RBC units per transfusion before transitioning from standard RCE to IHD-RCE (P = .0186). These findings challenge the assumption that IHD-RCE universally reduces donor blood needs. In patients with low TBV or RBC needs, IHD-RCE does not reduce, and may even increase, RBC use. Our findings underscore the importance of individualized transfusion strategies, especially during growth and puberty, because not all patients benefit from IHD-RCE.