- Why should blood be transfused?
- What should be transfused?
- How much to transfuse?
- How often to transfuse?
- Complications of transfusion
Why should blood be transfused?
Children living with Thalassaemia Major due to premature destruction of Red Blood Cells (RBCs) are not able to deliver oxygen to the different tissues and cells of the body. This very obviously will have fatal consequences. Blood transfusions, which will ensure that the children receive RBCs, therefore form the mainstay of treatment of Thalassaemia Major.
Since the children need RBCs, ideally Whole Blood should not be given. The children need to be transfused with RBCs, also called as ‘Packed Cells’, after cross-matching. The Packed Cells if saline-washed will minimize transfusion reactions. In summary, ideally saline-washed Packed Cells should be transfused. For further precaution depletion of leukocytes can be done by using either bedside filters or pre-storage filtration.
The quantity of Packed Cells to be transfused will depend upon the weight of the patient, Hb level of the patient, desired Hb level after transfusion and Haematocrit of the Packed Cells being transfused. As a Thumb Rule, the dosage is usually 10-15 ml/kg of patient’s body weight. In the case of anaemic patients (Hb<5 gm/dl) and patients with cardiac problems, the dosage of Packed Cells does not exceed 5 ml/kg of patient’ body weight.
Transfusion therapy should commence immediately after confirmation of the diagnosis of Thalassaemia Major. In most cases, the first transfusion is given when the Hb level drops below 7 gm/dl. Thereafter it is necessary to decide on a transfusion regimen. In recent times, there is a school of thought which talks about maintaining a very high Hb level. A super-transfusion regimen advocates a pre-transfusion Hb>11gm/dl with a mean Hb of about 14gm/dl. A hyper-transfusion regimen aims at at pre-transfusion Hb> 10gm/dl with a mean of about 12gm/dl. A moderate transfusion regimen tries to maintain the pre-transfusion Hb in the range of 9-10 gm/dl. Most Centres in India adopt the moderate transfusion regimen, which they believe leads to better control of iron overloading. Having decided on the transfusion regimen, the frequency of transfusions can be decided by monitoring the pre-transfusion Hb. The time taken for the Hb level to drop down to the desired pre-transfusion level should be figured. The frequency will vary from patient to patient, and will increase with the age/weight of the child.
Apart from the problem of iron overload, complication of repeated blood transfusions include non-haemolytic febrile reactions, alloimmunization and transfusion transmitted infections like HIV, Hepatitis B, Hepatitis C and Malaria.
Non-haemolytic transfusion reaction and alloimmunization can be prevented by leucoreduction at the prestorage stage (when the components are separated). However, most countries are not able to meet the huge costs of prestorage leucoreduction. The option of using bedside filters is available to the patient.
With respect to transfusion transmitted infections (TTIs), blood banks have to ensure that:
- blood is collected from voluntary donors
- mandatory screening is carried out for all TTIs
- Nucleic Acid testing is adopted for minimizing the threat of window period
Protection can be taken against Hepatitis B by taking vaccination as per the dose recommended by the doctor, with a booster dose after every 5 years.