What are the indications for blood transfusion in patients with sickle cell disease during acute crises?

Blood transfusion in patients with sickle cell disease during acute crises is indicated primarily for management of severe anaemia, acute splenic sequestration, acute chest syndrome, and other severe complications such as acute stroke or severe vaso-occlusive crises unresponsive to standard treatment. Specifically, transfusion is considered when there is an acute fall in haemoglobin, particularly if it results in symptomatic anaemia or if haemoglobin levels drop below restrictive thresholds (typically around 70 g/L in stable patients without major bleeding or acute coronary syndrome) ¹,³.

In acute chest syndrome, transfusion aims to reduce the proportion of sickled cells and improve oxygen delivery, often requiring exchange transfusion in severe cases ¹,². Acute splenic sequestration, especially in young children, is another indication where urgent transfusion is needed to manage rapid enlargement of the spleen and severe anaemia ¹.

Other indications include severe vaso-occlusive crises with complications such as stroke or multi-organ involvement, where transfusion can help reduce sickling and improve clinical outcomes ¹,². Elective transfusions may also be used in specific scenarios such as pulmonary hypertension or priapism, but these are generally outside the acute crisis context ¹.

Transfusion thresholds should be individualized, but restrictive transfusion strategies are recommended to avoid complications associated with over-transfusion, with targets generally aiming for haemoglobin concentrations of 70–90 g/L post-transfusion in most acute settings ³. Single-unit transfusions with reassessment are preferred to minimize risks ³.

Recent literature supports selective transfusion approaches tailored to the severity of the crisis and individual patient factors, emphasizing the importance of balancing benefits against risks such as alloimmunization and iron overload (Okusanya and Oladapo, 2013; Novelli and Gladwin, 2016).