Blood Products - Red Blood Cells

Transfusion threshold

Patients undergoing marrow suppressive therapy should be transfused on the basis of symptoms rather than the Hb level.  Younger children can generally tolerate a lower Hb.  If a patient is nearing their known transfusion tolerance it may be helpful to transfuse them prior to discharge so they don't need to return a couple of days later. If myelosuppression is expected to continue, transfuse earlier rather than waiting for Hb to drop to symptomatic levels.

There are situations when it is prudent to maintain Hb at a higher level:

• ongoing bleeding

• patient is experiencing symptoms from anaemia - this is particularly true of teenagers who may respond to a higher Hb threshold

• neonates

• patients receiving radiotherapy - keep Hb > 100 g/l.

There are also situations when transfusions should be limited where possible:

• aplastic anaemia (sensitization to transfusions may decrease the chance of a successful transplant)

• other bone marrow failure syndromes (e.g., Fanconi's, DBA) (as above)

• chronic anaemia (e.g., hereditary spherocytosis)

• a newly presenting patient with leukaemia and white cell count > 100 x 10⁹/litre should not be transfused without discussion with the treating oncologist, even if mildly/moderately symptomatic from anaemia. Increased circulating red blood cells plus hyperleucocytosis increases risk of hyperviscosity.

Transfusion volume

Order quantity by volume rather than units if possible:

Volume required = Required rise in Hb in g/L x weight (kg) x 0.4.

For example:

Hb 70 g/L aim is 110 g/L patient is 40 kg.

40 x 40 x 0.4 = 640 mL.

For patients of adult size this is 10-15 mL/kg for Hb of 80 g/L.

A RBC transfusion must be completed over a maximum of 4 hours. The usual rate is around 5 mL/kg/hr.

Diuretics are not routinely required. If there is fluid overload or a large volume transfusion then frusemide 0.5 - 1 mg/kg can be used.