Objective A new formula has been recommended to standardise the calculation of the volume required for blood transfusion across all age and diagnostic groups of patients in paediatric intensive care units (PICU). The application of the new formula was audited against clinical practice in the PICU in Birmingham Children’s Hospital, UK. Volume of packed cell (ml)  =  4.8 × weight (kg) × desired rise in haemoglobin (g/dl) (Morris 2005, Davies 2007).

Methods A comparison of the actual volume of blood transfused and the “ideal” volume of blood calculated from the new formula was documented in critically ill children. Confounding factors, eg, active bleeding, haemolysis, recent surgery and cyanotic heart disease, were taken into account.

Results Transfusion volumes were documented for 28 children (median age 16 days, range 3 days to 5 years) over 8 weeks. The correct volume (±10%) was transfused in 19 children. Five patients (18%) were over-transfused (factor of 6.3−7.5×). None of these patients had active bleeding or haemolysis. Four patients (14%) were under-transfused (factor 3.3−4.0×). Two of the patients that were under-transfused required a further blood transfusion within 3 days.

Conclusions The application of this new formula is not being widely used in clinical practice. The implementation of this formula could be improved by the introduction of electronic blood product prescribing and more widespread and purposeful education. An accurate calculation of volume required for paediatric patients could reduce multiple transfusions, reducing risks and cutting costs.