Thalassemia is caused due to lack of synthesis of haemoglobin (Hb) molecules carrying oxygen to different parts of the body resulting in the lysis of red blood cells (RBC’s) thereby causing anaemia. Blood transfusion is the only mainstay of care for thalassemia major and thalassemia intermedia (showing up late age at onset of the disorder) patients in order to maintain adequate oxygen supply to the tissues by maintaining haemoglobin levels near normal. According to Dr. Suman Jain, Chief Medical Research officer and Secretary, TSCS & Dr. Padma G, Research Scientist, TSCS, the current management involves repeated blood transfusion of packed cells (RBC’s) every two to four weeks regularly to maintain pre-transfusion Hb levels, 9.5-10g/dl.
Before initiating blood transfusion for a patient, the cause of anaemia should be ascertained first and the diagnosis should be confirmed. The first transfusion can be undertaken when the Hb level of the patient falls <7gms/dl or in a situation where there is poor growth, facial changes, fractures or extra medullary haematopoiesis.
Measures to be taken before embarking on transfusion therapy:
The patients should have extended red cell antigen typing including C, c, E, e, Kell in order to help identify and characterise antibodies in case of later immunisation. Efforts should be made to perform a full crossmatch and screen for new antibodies before every transfusion.
- All thalassemia patients should be transfused with ABO and Rh (D) compatible blood
- All patients should be screened for Hepatitis B, Hepatitis C, and HIV.
- All patients and their family members should be vaccinated for Hepatitis B if not vaccinated earlier.
Quality and adequacy of blood
Safety starts right from blood collection. In order to safeguard the health of the transfusion dependent thalassemia patient, blood should always be obtained from carefully selected regular voluntary, non-remunerated donors who have honestly answered a questionnaire (related to lifestyle, medication, travel, and medical history).
- All the donors have to be tested for all infectious markers like HIV, HCV, syphilis, HBsAg and malaria.
- Transfusion of blood from first-degree relatives should be avoided due to the risk of developing antibodies that might adversely affect the outcome of a later stem cell transplant. There is a risk of Graft Vs Host disease on Bone Marrow Transplantation (BMT).
- Freshly packed red blood cells (not>7 days old) should be used for transfusion to maintain maximum viability of red cells. Leukoreduction minimises the transfusion reactions.
- Pre-storage filtration is the best method to remove leucocytes from a donor's blood followed by pretransfusion laboratory filtration.
- Bedside filters can be used in the absence of these techniques. Saline washed red cells are indicated if repeated allergic transfusion reactions occur.
- Transfusion of the blood units should be completed within four hrs after it is removed from controlled temperature storage (CTS) as the risk of bacterial proliferation increases with time especially in a warm ambient temperature.
Transfusion Process
The recommended treatment for thalassemia major involves transfusion of 10-15ml/kg body weight of leukoreduced packed RBCs for over three to four hrs to maintain a pretransfusion haemoglobin level above 9–10.5 g/dl. This promotes normal growth, allows normal physical activities, adequately suppresses bone marrow activity in most patients, and minimises transfusional iron accumulation.
In case of congestive cardiac failure, a child may be given 5-8 ml/kg of packed cells at one time over four to six hours along with a diuretic.
Information pertaining to date of transfusion, bag number, and amount of the blood transfused, height and weight of the patient, liver and spleen size, and details of transfusion reactions should be recorded at each transfusion to assess the annual requirement, cause of reactions, tracing of transfusion infections and the impact of transfusions.
Adverse reactions and management
Blood transfusion may expose the patient to a variety of risks.
- Acute haemolytic reaction (AHR) is a life threatening complication that occurs immediately within five to 10 minutes of blood transfusion due to ABO incompatibility.
- Infectious agents like viruses, bacteria, and parasites may be transmitted through blood due to window period, sensitivity threshold of tests, etc.
- Transfusion-related acute lung injury (TRALI), is a clinical syndrome which may occur during or after a transfusion in which there is acute, noncardiogenic pulmonary edema associated with hypoxia.
- Other adverse reactions include febrile nonhemolytic transfusion reactions, allergic reactions, urticaria, anaphylaxis, acute non immune mediated reactions etc.,
Thus, it is vital to continue improving blood safety and to find ways of reducing transfusion requirements and the number of donor exposures.
Image credits- freepik
Data credits- Blood Transfusion Therapy in β-Thalassaemia Major
