How to transfuse
Dr. Lal said the pretransfusion hemoglobin target is 10 g/dL, with a range of 9.5-10.5 g/dL in beta thalassemia major and a range of 9.0-10.5 g/dL for E beta thalassemia. A target of 10 g/dL is adequate for most individuals, Dr. Lal said, but he recommends individualization of hemoglobin target for patients with E beta thalassemia.
In general, patients should be transfused every 3 weeks, although 4 weeks is acceptable in younger children and those with hemoglobin E beta thalassemia.
As for the volume of a transfusion, children should receive 4 mL per kg of body weight, per gram increase in hemoglobin desired. Partial units can be used to avoid undertransfusion.
For adults, in general, those with pretransfusion hemoglobin less than 10 g/dL should receive three units, and those with pretransfusion hemoglobin of 10 g/dL or greater should receive two units.
The hemoglobin threshold should be adjusted based on fatigue or bone pain, Dr. Lal said. He also noted that patients with intact spleens have higher transfusion needs.
The rate of transfusion should be 5 mL/kg/hour in children and 200-300 mL/hour in adults, based on tolerance. Patients with impaired cardiac function should receive a reduced blood volume at a reduced rate.
Non–transfusion dependent thalassemia
Dr. Vichinsky discussed recommendations for non–transfusion dependent thalassemia (NTDT), noting that these patients may need transient transfusions to prevent morbidity.
Hemoglobin should not be the sole determinant of transfusion need in NTDT patients, he said. Their well-being – activity level, growth, and skeletal changes – is more important than hemoglobin levels. However, patients with hemoglobin levels less than 7 g/dL often have severe morbidity, and those with levels of 10 g/dL or greater are usually protected from severe morbidity.
Indications for transfusion in NTDT patients include:
- Growth failure.
- Hematopoietic tumors.
- Pulmonary hypertension.
- Silent brain infarcts.
- Skin ulcers.
- Severe bone pain.
- Poor quality of life.
- Frequent hemolytic crises.
- Marked and enlarging spleen.
- Failure of secondary sex development.
- Cosmetic and facial changes.
“There is a risk to transfusing this population,” Dr. Vichinsky said. “They’re older, and when you transfuse them, they can get iron overloaded.”
He added that splenectomized NTDT patients have a high risk of alloimmunization, and the transfusion duration should be serially reevaluated in NTDT patients.
Alpha thalassemia major
For alpha thalassemia major, Dr. Vichinsky discussed the importance of prevention, screening, and fetal therapy. He said couples with a fetus at risk of alpha thalassemia major should be identified early and offered, in addition to termination, the option of early fetal transfusion.
Dr. Vichinsky recommended prenatal testing and monitoring of at-risk pregnancies with ultrasound. If the fetus requires a transfusion, monitoring hemoglobin Barts and hemoglobin A is necessary.
A fetus that requires a transfusion should receive packed red blood cells that are cytomegalovirus negative, are less than 7 days old, have been irradiated, have a hemoglobin mass greater than 75%, and have been optimally cross matched with the mother first.
“These babies appear, with serial transfusions, to survive and have a relatively normal neonatal period,” Dr. Vichinsky said.
He added, however, that postnatal management of alpha thalassemia major involves an aggressive transfusion protocol. These patients should be transfused to a higher hemoglobin level than patients with beta thalassemia – roughly 12 g/dL versus 10 g/dL.
These and Dr. Lal’s recommendations are based on information in the Standards of Care Guidelines for Thalassemia – Oakland 2011, the Thalassemia International Federation Guidelines – 2014, the Thalassemia Management Checklists: United States – 2018, the Thalassemia Western Consortium Consensus: US – 2019, and the International Collaboration for Transfusion Medicine Guidelines – 2019.
Dr. Lal and Dr. Vichinsky did not disclose any conflicts of interest.