Red Cell Transfusion in Stable Anaemia

Stable anaemia means a patient who is not bleeding and not haemodynamically unstable, in whom anaemia is acute, subacute or chronic and compensation is adequate or partly adequate. Most of these patients do not need transfusion. When transfusion is needed, the safest approach is a single unit followed by reassessment of symptoms and haemoglobin before any further unit.

Principle. The goal is relief of symptoms and safe oxygen delivery, not a normal haemoglobin. The cause must be found and treated at the same time.

Risk context. Chronic anaemia is a state of expanded plasma volume, so rapid or repeated transfusion causes circulatory overload, especially with heart failure, renal failure, severe malnutrition, older age and very low haemoglobin. Transfusion also increases the risk of alloimmunisation and, with repeated use, iron overload.

Special groups. Severe chronic anaemia in children and in pregnancy, haemoglobinopathies, chronic kidney disease, haematological malignancy and the older adult with cardiac disease.

Assess the patient, not the number. Ask about exertional dyspnoea, chest pain, syncope, palpitations, heart failure, cognitive change and functional limitation. Examine for tachycardia, hypotension, flow murmurs, signs of heart failure and pallor.

Usual thresholds.

• Haemoglobin under 7 g/dL in a stable hospitalised adult is the usual point at which transfusion is considered.

• Haemoglobin 7 to 8 g/dL with established cardiovascular disease, after orthopaedic surgery, or in symptomatic patients.

• Haemoglobin under 7 g/dL with no symptoms and a treatable cause (iron, vitamin B12, folate deficiency) may be managed without transfusion, with close follow up.

• In children in malaria endemic regions, haemoglobin under 4 g/dL, or under 6 g/dL with respiratory distress, shock or impaired consciousness, is a usual indication.

Find the cause. Blood film, reticulocyte count, ferritin, vitamin B12, folate, malaria testing, stool for helminths, renal and liver function, HIV status, haemolysis markers and, where indicated, haemoglobin variants and bone marrow examination.

Red flags. Haemoglobin falling in hospital (hidden bleeding or haemolysis), anaemia with fever or jaundice, anaemia with bleeding at another site, and transfusion requirement that recurs soon after.

One unit and reassess.

1. Confirm the indication and consent.

2. Give one unit of red cells over 2 to 4 hours, completed within 4 hours of leaving controlled storage.

3. Reassess symptoms and vital signs at completion.

4. Check haemoglobin about 1 hour after completion.

5. Order a further unit only if the threshold is still crossed or symptoms persist.

Expected response. One unit raises haemoglobin by about 1 g/dL in a 70 kg adult without ongoing loss. A smaller rise points to bleeding, haemolysis, haemodilution or splenic sequestration.

Rate and cardiac risk. In patients with heart failure, renal failure, severe chronic anaemia or older age, about 1 mL/kg/hour, with a diuretic only if there are signs of volume overload, and with each unit completed within 4 hours.

Treat the cause at the same time. Iron, vitamin B12, folate, antimalarial therapy, anthelmintic therapy, control of haemolysis, and management of chronic kidney disease.

Special groups.

• Children: 10 to 15 mL/kg of red cells, or 20 mL/kg of whole blood for severe anaemia, at a slower rate (about 5 mL/kg/hour), with reassessment.

• Pregnancy: severe anaemia near term is corrected before labour where possible, using single units and attention to overload.

• Sickle cell disease: avoid raising haemoglobin over 10 g/dL.

• Chronic kidney disease: transfuse only when erythropoiesis stimulating agents and iron are inadequate or the need is urgent, and avoid sensitisation in patients who may need a transplant.

Monitoring. Temperature, pulse, blood pressure, respiratory rate and oxygen saturation before, at 15 minutes and at completion. Watch for breathlessness, raised jugular venous pressure and crepitations during and for 6 hours after.

Complications. Circulatory overload, febrile and allergic reactions, haemolysis, and iron overload with repeated transfusion.

Referral and escalation. Haematology for unexplained or refractory anaemia, repeated transfusion need, and suspected haemolysis. Cardiology or nephrology when heart or kidney disease limits volume.

Disposition. Discharge only when haemoglobin is stable and the cause is being treated. Arrange follow up haemoglobin and ferritin, and give a plan so that further transfusion is avoided.