Blood Transfusion

Estimated total blood volume:

• Premature neonates: 100ml/kg.
• Term neonates: 90ml/kg.
• Infants: 80ml/kg
• Children & adults: 70ml/kg.

Permissible blood loss or blood replacement:

Method 1: Red Cross Childrens’ Hospital formula:

(1) Hct x TBV = PCV (current or starting packed cell volume).

(2) Hct x TBV = PCV (accepted minimum).

(1) – (2) PCV (permissible loss)

Permissible TBV loss = PCV/Hct.

Note: Use Haematocrit as decimal (eg. 36% = 0.36).

Method 2: Dr Tony Butt’s rule of thumb (much easier):

If one assumes an Hb of 10g/dL as normal (rule of thumb), then each 10% aliquot of total blood volume will drop or raise Hb by 1g/dL.

Whole Blood

• 6ml/kg of whole blood for 1g increase HB
• Therefore: Volume to be transfused (mls) = desired HB - actual HB x weight x 6

Packed Cells

• 4ml/kg of whole blood for 1g increase HB
• Therefore: Volume to be transfused (mls) = desired HB - actual HB x weight x 4