Blood Transfusion and Component Therapy in Children
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Direct answer
Blood transfusion in children replaces a specific deficit with the smallest effective component rather than defaulting to whole blood. Packed red cells at 10 mL/kg raise haemoglobin by about 2 g/dL in a child who is not bleeding, while plasma, platelets and cryoprecipitate correct clotting factors and platelet counts. Irradiated products are required for immunocompromised children, and leucodepletion reduces febrile reactions, HLA alloimmunisation and CMV transmission.
What you must remember
- Packed red cells: give 10 to 15 mL/kg, with each 10 mL/kg raising haemoglobin by about 2 g/dL, and complete the infusion within four hours of issue.
- Fresh frozen plasma: 10 to 15 mL/kg corrects multiple clotting factor deficiency, as seen in liver failure, disseminated intravascular coagulation or massive transfusion.
- Platelets: about one random donor unit per 10 kg of body weight raises a low count, and platelets correct platelet numbers, not clotting factors.
- Cryoprecipitate: a source of fibrinogen, factor VIII, von Willebrand factor and factor XIII, used for hypofibrinogenaemia and selected bleeding disorders.
- Irradiated products: required for congenital immunodeficiency, intrauterine transfusion, stem cell transplant recipients and patients on purine analogues, to prevent transfusion-associated graft-versus-host disease.
- Leucodepleted products: reduce febrile non-haemolytic reactions, HLA alloimmunisation and cytomegalovirus transmission, and are the usual standard in many blood services.
- Acute haemolytic reaction: ABO incompatibility causes fever, haemoglobinuria, back pain and possibly disseminated intravascular coagulation, so the transfusion is stopped at once.
- Other reactions: urticaria, transfusion-related acute lung injury, transfusion-associated circulatory overload, and hypocalcaemia or hyperkalaemia after massive transfusion.
A pathway for prescribing a red cell transfusion
A 3-year-old with severe anaemia from a chronic illness needs a red cell transfusion. The steps below cover the product, dose and monitoring.
- Confirm the indication: decide using the clinical state and haemoglobin together, since a single number does not dictate transfusion in chronic anaemia.
- Calculate the volume: give 10 to 15 mL/kg of packed red cells and check the expected rise of about 2 g/dL per 10 mL/kg.
- Select the product: choose leucodepleted red cells, and irradiated units only for the immunocompromised groups listed above.
- Check compatibility: perform ABO and Rh grouping, cross-match and confirm consent before the unit leaves the blood bank.
- Infuse safely: start slowly and watch closely for an early reaction, then complete the infusion within four hours of issue.
- Monitor for reactions: record vital signs before, during and after the transfusion, looking for fever, rash, breathlessness or dark urine.
- Act on a reaction: stop the transfusion, return the bag and a fresh sample to the blood bank, and treat according to the reaction type.
Where the exam tries to catch you
Transfusion questions reward precise product choice and recognition of the reaction that matters most.
- Trap: calling every fever during a transfusion a febrile non-haemolytic reaction. Correct: stop the transfusion and exclude an acute haemolytic reaction first, because fever with ABO incompatibility can be life-threatening.
- Trap: giving fresh frozen plasma to correct a low platelet count. Correct: platelets correct the platelet number, whereas plasma supplies clotting factors and does not raise the count meaningfully.
- Trap: irradiating every product as routine. Correct: irradiation is for specific immunocompromised and intrauterine groups, whereas leucodepletion is the routine safeguard.
Frequently asked questions
What volume of packed red cells is usually given to a child?
Packed red cells are usually given at 10 to 15 mL/kg in children. A volume of 10 mL/kg raises haemoglobin by about 2 g/dL in a child who is not actively bleeding, and the dose is checked against the target haemoglobin and clinical state.
When must blood products be irradiated?
Irradiation is required for children with congenital immunodeficiency, for intrauterine transfusions, for haematopoietic stem cell transplant recipients and for patients receiving purine analogues. It prevents transfusion-associated graft-versus-host disease, which is almost always fatal.
What does leucodepletion prevent?
Leucodepletion removes most white cells from a blood component, which reduces febrile non-haemolytic reactions, HLA alloimmunisation and transmission of cytomegalovirus. It does not prevent acute haemolytic reactions, which depend on ABO and Rh compatibility.
How are transfusion reactions managed in a child?
The transfusion is stopped immediately, and the bag and a fresh blood sample return to the blood bank. Acute haemolytic reactions need urgent review of renal function and clotting, while urticaria responds to antihistamines and fever is treated only after haemolysis has been excluded.