Blood Transfusion in Sickle Cell Disease

Simple (Top-Up) Blood Transfusion

Simple transfusion is indicated in patients with symptomatic anaemia or when the haemoglobin concentration has fallen by >2 g/dL below the patient's steady-state baseline.

Exchange Blood Transfusion

The goal of exchange transfusion is to reduce HbS to ≤30% while avoiding excessive increases in total haemoglobin and blood viscosity.

Indications

• Acute ischemic stroke or other cerebrovascular events

• Acute chest syndrome (moderate to severe)

• Major surgery requiring general anaesthesia

• Multi-organ failure, including systemic marrow fat embolism syndrome

• Multiple pregnancy in selected high-risk patients

• Secondary prevention of recurrent stroke

Relative indications

• Recurrent severe vaso-occlusive crises refractory to optimal medical therapy

• Severe or prolonged priapism unresponsive to standard treatment

Important Considerations

• Routine transfusion is not recommended for patients in steady-state sickle cell disease solely because the haemoglobin level is 8–10 g/dL, as these patients are physiologically adapted to chronic anaemia.

• Packed red blood cells (PRBCs) are preferred over whole blood to minimize the risk of volume overload.

• Avoid raising the haemoglobin concentration above 10–11 g/dL with simple transfusion to reduce the risk of hyperviscosity.

• Blood should be appropriately cross-matched, and patients should be monitored for transfusion reactions, alloimmunization, iron overload, and transfusion-transmitted infections.

• Exchange transfusion is preferred over simple transfusion when rapid reduction of HbS is required without significantly increasing blood viscosity.