ToolsCalculators
Sickle Cell RBC Exchange Volume
Sickle Cell RBC Exchange Volume
Sex
Height
Weight
Patient hematocrit
%
Initial HbS
%
Goal HbS
%
Hematocrit of transfused RBCs
%
Complete the fields above to see the result.
When to use
- Planning automated (isovolaemic) red cell exchange for acute or chronic complications of sickle cell disease.
Formula
Total blood volume by the Nadler equations; patient RBC volume = TBV x hematocrit. Fraction of cells remaining (FCR) = goal HbS / initial HbS. Donor RBC volume = RBC volume x (-ln FCR); product volume = donor RBC volume / hematocrit of transfused RBCs.
Pearls and pitfalls
- Assumes donor units are HbS-free, so post-exchange HbS approximates FCR x initial HbS.
- A rough single-compartment estimate; the apheresis device and blood bank refine the actual replacement volume.