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Blood product management during paediatric Cardio Pulmonary Bypass (CPB)

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  • Blood and blood product transfusion can have serious adverse effects.
  • There is some good evidence that a Hct less than 0.3 results in a worse neurological outcome in paediatric patients undergoing CPB.
  • The most common coagulation defect post CPB is a defect of platelet function and/or an absolute decrease in platelet number.
  • There is very little need for FFP to treat coagulopathy in children post CPB.
  • Neonates and infants have an immature coagulation system.
  • There are some patients who are more likely to bleed post CPB and in these patients there should be a lower threshold for coagulation factor administration.
  • Antifibrinolytic treatment limits blood loss - aprotinin may be superior to high dose tranexamic acid in neonates.
  • Coagulation tests should be performed after initial coagulation component treatment including TEG if available.
  • The role of recombinant factor VIIa is unclear but it can be effective in cases of severe bleeding without surgical cause and despite normal coagulation tests.


Aim for a Hct on CPB of 0.3 in all patients on CPB

This may be slightly less in an older child having a straightforward procedure as it may be possible to avoid transfusion entirely in these patients. However the HCT should NEVER be less than 0.26.

In neonates, cyanotic patients, and those who have been very polycythemic preop (Hct > 0.6) a Hct > 0.35 should be targeted when coming off CPB and some of these patients may benefit from running their Hct on CPB at this level. The surgeon needs to be made aware of the Hct during rewarming so that the patient comes off bypass with an acceptable Hct.

Post bypass MUFing is performed on most patients for 15-20 minutes to remove excess water and to allow for haemoconcentration to the desired haematocrit (usually 5-10 points above the Hct coming off bypass). This also allows for the transfusion of blood products without haemodiluting the patient.

Blood Component Therapy in OR

  1. Platelets
    Patients less than 5 kilograms undergoing CPB will usually undergo a platelet transfusion of 10-20ml/kg while MUFing post bypass. Ideally these platelets should be single donor platelets ie one or more neonatal units or a single adult platelet pheresis unit.

    Older patients undergoing redo surgery, DHCA, or prolonged CPB may also benefit from platelet infusions as will those who have been on aspirin pre-op.

    Platelets can have a serious negative inotropic effect on the heart immediately post CPB. In patients with poor myocardial function they need to be given very slowly and often accompanied by calcium infusion +/- a temporary increase in inotropes. It is advisable to delay platelet transfusion for 5-10 mins after coming off CPB and starting to MUF in patients with poor ventricular function.
  2. Cryoprecipitate
    Patients less than 5 kilograms and those undergoing DHCA may also require a cryoprecipitate transfusion of 10ml/kg. For patients > 15kg give 1 unit up to 25kg then 1 unit per 25kg.

    This should be added to the bypass circuit during rewarming.
  3. Fresh Frozen Plasma
    Fresh frozen plasma is very seldom indicated but if required is dosed at 10ml/kg. There may be an increased requirement for this now that the platelets are no longer suspended in plasma.

    This should be added to the bypass circuit during rewarming.
  4. Activated Factor VII
    Ongoing blood loss without repairable surgical cause and with relatively normal coagulation profile may exceptionally be treated with activated factor VIIa (dose 30-90microgm/kg).


Do not treat coagulation results in isolation, i.e. if the patient is not bleeding then the coagulation does not have to be normalised.

Minimise bleeding by controlling systolic blood pressure and atrial filling pressures.

Avoid excessive volumes of blood component transfusion post CPB which can lead to atrial overdistension and exacerbate bleeding from atrial suture lines.

Patients who receive blood products should have a FBC and coagulation screen taken with their post protamine ACT. Usually they will also have a TEG done at this stage.

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  • Date last published: 01 June 2017
  • Document type: Clinical Guideline
  • Services responsible: Paediatric Intensive Care Unit
  • Owner: Dave Buckley
  • Editor: John Beca
  • Review frequency: 2 years