Discussion Forums > Thalassemia Major

Transfusion problems

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Andy Battaglia:
Maha,

There are formulas that doctors use to determine the volume needed for transfusion. I am certain your doctor is abiding by the formula and does not want to exceed the volume indicated by the formula. In the young and elderly, this is most important as to avoid unnecessary transfusion complications, specifically volume overload. The formula is based on hematocrit before transfusion, desired hematocrit after the transfusion and the weight of the patient. It is in the best interest of the patient to abide by this formula. The result is to minimize both the iron intake and the stress that transfusion volume can have on the heart.

The formula, from http://www.scinfo.org/transfus.htm


--- Quote ---Formulas of use in Blood Transfusion (Useful Approximations):

Total Blood Volume = 70 cc X Weight in kg.or 75 cc X Weight in Kg (With chronic anemia).

Red Cell Volume of Patient = Total Blood Volume X Hematocrit

Giving 3 cc/kg of packed red cells will raise the hemoglobin by 1 gm/dl

Giving 10 cc/kg of packed red cells will raise the hematocrit by 10 points (vol%) or hemoglobin by about 3 gm/dl

Quick Formula to Approximate Volume of Red Cells for Transfusion

Transfusion volume = [Total Blood Volume X (Hcrit goal - Hcrit pre Tx)]/ Hcrit of Donor Unit

Example: For 50 kg person with pre-transfusion Hcrit 23%, goal Hcrit 30%, average PRBC unit Hcrit 70%,

[(75 cc/kg) (50 kg) (0.30 – 0.23)]/0.70 = 375 cc (or 7.5 cc/kg)

Hematocrit of donor unit average values in transfused units

Whole blood donor unit average Hematocrit = 35%

Packed red cell unit average Hematocrit = 70%

PRBC unit with AdSol averages Hematocrit = 60%

Those being treated for acute anemia, aplastic crisis, heart failure, splenic sequestration, and bleeding should be given packed cells to raise the hematocrit to 28 - 33 vol.%. Patients should receive further transfusions based on symptoms.
--- End quote ---

Caution is the word when transfusing those with the lowest blood capacity. Infants, young children and the elderly all fall into this category. Many steps are taken to make transfusion as safe as possible, and restricting the blood volume taken is one of these steps.

maha:
Hi Andy
For the past 2 years his doc has been following 15ml/kg formula. Hassan weighs 16.8kg and this time he was given 220cc which is around 13ml/kg. Probably the doc has decided to take some interest in his case, by the way he is only a paediatrician and not a thal specialist.

Maha

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