Neonatal Transfusion

Neonates have a small blood volume (about 85 to 90 mL/kg), immature organs and little tolerance for error. Transfusion decisions depend on gestational and postnatal age, respiratory and cardiovascular state, and laboratory values. Thresholds are deliberately restrictive, products are specially selected and exposure to multiple donors is limited.

Product specifications. Red cells that are leucodepleted, cytomegalovirus safe, fresh enough for the indication and, for intrauterine and exchange transfusion, irradiated. Small aliquots from a single donor unit reduce donor exposure. Group O RhD compatible units are used when maternal antibodies are present.

Risk context. Hyperkalaemia, hypocalcaemia, hypothermia, volume overload, necrotising enterocolitis in preterm infants, transfusion associated lung injury, infection and graft versus host disease.

Special groups. Extremely preterm infants, infants with haemolytic disease, infants of mothers with antibodies, and those on respiratory support. In East Africa, hyperbilirubinaemia from ABO and RhD incompatibility and from glucose-6-phosphate dehydrogenase deficiency is a recognised cause of exchange transfusion, and delay in reaching facilities adds risk.

Red cells. Thresholds depend on age and support, and are set by the neonatal service. Approximate ranges for haemoglobin:

• First week with severe respiratory disease or ventilation: about 11 to 12 g/dL.

• First week, stable on low support: about 10 g/dL.

• Second week: about 10 g/dL on support, about 8 to 9 g/dL when stable.

• From the third week, stable: about 7 to 8 g/dL, with symptoms (apnoea, poor weight gain, tachycardia, high lactate) being the reason to go higher.

• Acute blood loss over 10% of blood volume with shock: transfuse regardless of haemoglobin.

Platelets. Usual thresholds in non-bleeding neonates: under about 25 x 10⁹/L (prophylaxis), under 50 x 10⁹/L with bleeding, before invasive procedures or with sepsis, and under 100 x 10⁹/L for major bleeding or neurosurgery. Neonatal alloimmune thrombocytopenia requires human platelet antigen compatible or washed maternal platelets, started without waiting for confirmation when bleeding or very low counts are present.

Plasma and cryoprecipitate. Only for bleeding with documented coagulopathy, or before an invasive procedure with documented deficiency. Prophylactic plasma in preterm infants is not advised. Vitamin K prophylaxis (1 mg intramuscularly at birth, 0.5 mg if birth weight is under 1 kg) prevents most vitamin K deficiency bleeding.

Exchange transfusion indications.

• Severe hyperbilirubinaemia over the gestation and age specific exchange line, or rising bilirubin despite intensive phototherapy, or signs of acute bilirubin encephalopathy.

• Haemolytic disease of the foetus and newborn with anaemia and rapidly rising bilirubin.

• Severe polycythaemia with symptoms (rare).

Red flags. Lethargy, hypotonia, high pitched cry, arching and fever with jaundice, which indicate bilirubin neurotoxicity and need immediate action.

Red cells. 10 to 20 mL/kg (often 15 mL/kg) over 3 to 4 hours, at about 2 to 5 mL/kg/hour, from a dedicated unit with aliquots, reassessing after the dose. In acute bleeding, rapid warmed blood.

Platelets. 10 to 20 mL/kg (often 10 to 15 mL/kg) over 30 to 60 minutes, ABO compatible where possible, plasma reduced or low titre.

Plasma. 10 to 20 mL/kg over 1 to 2 hours. Cryoprecipitate 5 to 10 mL/kg.

Exchange transfusion.

• First give intensive phototherapy, intravenous hydration and, in immune haemolytic disease, intravenous immunoglobulin 0.5 to 1 g/kg.

• Use fresh (under 5 days) group O RhD compatible red cells reconstituted with compatible plasma to a haematocrit of about 50 to 55%, irradiated and cytomegalovirus safe, or the unit selected by the blood bank. The unit must be compatible with the baby and with maternal antibodies.

• Double volume exchange is about 160 mL/kg (twice 80 mL/kg), done in aliquots of 5 to 10 mL over 60 to 90 minutes, by an umbilical or peripheral route, with warming.

• Monitor heart rate, oxygen saturation, temperature, glucose, calcium, potassium and platelets before, during and after, and give calcium if signs or low levels occur.

• Rebound bilirubin is expected, so recheck 2 to 4 hours after.

Special groups.

• Preterm infants: minimise donor exposure, small aliquots, restrictive thresholds, fresh enough units.

• Mothers with antibodies: crossmatch against maternal plasma, and use antigen negative units.

• Infants with sickle cell disease: not an issue in the first months because of foetal haemoglobin.

Monitoring. Heart rate, respiratory rate, oxygen saturation, temperature and blood pressure before, during and after each transfusion, and haemoglobin, bilirubin and glucose as relevant. After exchange, monitor for 24 hours.

Complications. Apnoea, bradycardia, hypothermia, hypocalcaemia, hypoglycaemia, hyperkalaemia, thrombocytopenia, necrotising enterocolitis, infection, catheter complications and, rarely, death.

Referral and escalation. Neonatologist and blood bank for all exchange transfusions. Transfer early to a centre with capacity for exchange when bilirubin approaches the exchange line.

Disposition. After exchange, continue phototherapy, follow bilirubin and haemoglobin, monitor for late anaemia in haemolytic disease (up to 6 to 12 weeks) and arrange hearing and neurodevelopmental follow up.