Transfusion in fetuses, neonates, older children (BSH 2016)

 

Definitions

Neonate – up to 28 days

Infant – 28 days to 1 year

Clinically significant bleeding = WHO bleeding grades 2-4 (of total range 1-4)

 

Blood Components - basic requirements

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Red Cells - additional requirements

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Platelets - additional requirements

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FFP and Cryo - additional requirements

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Granulocytes - additional requirements

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Plasma components

Imported for all patients born after 1st jan 1996

Methylene Blue (MB) treatment results in 25-30% reduced factors VIII, XI, FGN and reduced thrombin generation. This is of uncertain clinical significance.

Solvent Detergent (SD) treatment results in reduced protein S, antitrypsin and antiplasmin and has been associated with thrombosis.

 

 

Neonates

 

Intrauterine transfusion (IUT) / Fetal Blood Sampling (FBS)

 

Continuous ultrasound, can be performed ages 16-35 weeks

Risks: 1-3% fetal death per procedure, up to 20% in hydrops fetalis

AE’s: miscarriage, preterm labour, fetal bradycardia, cord haematoma, vessel spasm, bleeding from puncture site.

QA – 2 specialists + minimum 15 procedures per year

 

Red cell IUT

Indications: HDN 2o to anti-D, -c or –k, or fetal parvovirus

Middle cerebral artery peak systolic velocities (MCA PSV) for non-invasive diagnosis

Transfuse aiming for Hct 0.45

Aim for delivery at 37-38 weeks

24 hours to prepare – in emergency irradiated red cell exchange units or irradiated paedipacks are acceptable.

 

Post-delivery Management

Monitor for several weeks, risk of haemolysis / bone marrow suppression in neonates that were transfused for HDN.

Anaemia beyond a few weeks usually result of passively acquired maternal antibodies (jaundice, haemolytic blood film).

Late anaemia follows transient suppression of neonatal erythropoiesis by transfusion.

 

Platelet IUT

Indication: Neonatal Alloimmune Thrombocytopenia (NAIT)

Almost all cases due to alloantibodies to HPA-1a (80-90%), HPA-5b and HPA-3a

Treat mother with steroids / IVIg in first instance to avoid IUT

Greatest risk at plt count <50

Transfuse more slowly than red cells due to risk of circulatory stasis / stroke

 

Neonatal Red Cell Transfusion

 

15ml/kg for non-bleeding neonates

 

Principles

Guidelines developed based on studies for VLBW pre-term babies (<1.5Kg)

Most pre-term babies require transfusion, often iatrogenic anaemia

(e.g. 0.5ml blood sample in 500g infant equalt to 70ml in a 70kg adult)

Transfusion thresholds debatable –restrictive threshold has slight advantage

 

Red cells

Indications: Surrogate markers of anaemia – poor growth, lethargy, apneic episodes

Risks: as for adults + necrotizing enterocolitis (NEC)

Use of paedipacks reduces donor exposure for multiply transfused neonates

 

Exchange blood transfusion (EBT)

Indications: rapidly rising bilirubin not response to phototherapy or IVIg. Or for severe anaemia.

Used in HDN to prevent bilirubin encephalopathy and removes antibody-coated red cells and excess bilirubin.

Other uses include other causes of neonatal hyperbilirubinaemia – e.g. G6PD def

Single blood volume EBT removes 75% of neonatal RBC’s, double vol up to 85-90%, and 50% of circulating bilirubin.

 

EPO

May reduce need for transfusion. Risk of retinopathy of prematurity (due to stimulated neovascularization).

 

Placental transfusion and delayed cord clamping (DCC)

Where baby does not need resuscitation, DCC of 1 minute increases Hb, reduces frequency of iron def at 2-6 months and reduced transfusion requirement.

 

Surgery and large volume transfusion (non-cardiac)

Definition – 80ml/kg in 24 hours or 50% of circulating volume in 3 hours

To avoid hyperkalaemia  /hypothermia à red cells <5 days old, within 24 hours of irradiation, transfused through blood warmer.

 

Neonatal Platelet Transfusion

 

RCT of prophylactic plt transfusion thresholds is ongoing in UK (PLANET1 and 2)

In absence of evidence, NICU’s often use plt count <25 as trigger for transfusion

NAIT – monitor with cranial USS for hemorrhage. No bleeding, Tx <25, bleeding aim for 50-100. IVIg alternative if HPA-1a/5b neg platelets do not increment. Resolves spontaneously 1-6 weeks after birth.

 

Neonatal FFP / Cryoprecipitate

 

Uncertainty around appropriate use of FFP prophylaxis

Studies show inconsistent benefit of coagulopathy screening and early plasma use to prevent intracranial bleeding. 1996 study showed no benefit (but neonates are younger now)

 

Normal values for PT/APTT poorly defined in neonates

‘Normal’ local population samples hard to attain + variation in analysers and reagents means difficult to interpret results. This most affects APTT.

PT raised by polycythaemia.

 

Neonatal purpura fulminans (PF)

Skin necrosis and DIC secondary to severe protein C or S deficiency

Early recognition and treat with FFP. Prot C concentrate available. No Prot S.

 

T-activation

 

Occurs in neonatal sepsis, particularly NEC and S.pneumoniae.

Neuroaminidase produced by infective organism strips sialic acid from red cell surface, exposing the T-cryptantigen.

Detectable by lectin panel.

Anti-T antibodies are naturally occurring IgM, developing in infancy.

Where haemolysis post-transfusion occurs and high suspicion this is due to anti-T, could consider:

  • Red cells in SAGM (little plasma present)

  • Low-titre anti-T FFP

  • Washed platelets in platelet suspension medium

 

Infants and Children

 

Calculate Vol. = (Desired Rise in Hb x weight(kg) x 4) / 10

 

Principles

 

50% of paediatric transfusion to non-neonates go to haem-onc patients

Other groups – cardiac surgery, PICU, ECMO

Children receiving regular transfusions should be vaccinated for Hep B

Those on chronic transfusions should have extended red cell phenotyping/genotyping, e.g. haemoglobinopathies, aplastic anaemia

Monitor growth – e.g. restrictive transfusion in thalassemia may impair it

 

Red cell transfusion

 

PICU

TRIPICU 2007 – restrictive threshold (70g/l) reduced blood use, no extra harm

Phlebotomy losses contribute to anaemia and increased blood requirement

 

Stem cell transplant / oncology

No specific guidance, current practice suggests 70-80g/l threshold is appropriate

?Tx for thalassemia - ?hypertransfuse to improve engraftment. Not been proven.

 

Surgery (non-cardiac)

Craniofacial, scoliosis and cardiac surgery cause greatest blood loss

Correct iron def pre-op

Tranexamic acid reduces blood loss – best dose and side effects not fully established

As for PICU, transfusion threshold of 70g/l

Consider cell salvage

 

Platelet Transfusion

 

Principles

No data on transfusion thresholds in haem-onc

Howard et al 2000 – 941 LP’s performed on children with plt <50 and without prophylactic plt transfusion found no bleeding events.

Survey of UK paed centers plt threshold prior to LP found variation of 10-80

 

FFP & Cryoprecipitate

 

Principles

Very little evidence of most current uses of FFP in infants and children

Should not be used to correct minor PT defects in non-bleeding pts prior to surgery

Suggested FGN threshold of 1.0g/l for transfusion

Major indications or cryoprecipitate in infants and children are DIC with bleeding,

bleeding following cardiac surgery and major haemorrhage.

 

 

Major Haemorrhage

 

Blood volume of children approx. 80ml/kg

Major haemorrhage = 80ml/kg in 24 hours, 40ml/kg in 3 hours or 2-3ml/kg/min

Management as for adults

 

Volume to transfuse = (Desired Hb – Actual Hb) x Weight x Factor / 10

Factor can be between 3-5, often 4 is used

4ml/kg is approx. equal to a one unit transfusion in an adult, raising Hb by 10g/l

Maximum 20ml/kg