Aggressive use of red blood cell transfusion for very premature infants born before 29 weeks of pregnancy and those weighing less than 1,000 grams (slightly more than two pounds) does not improve survival. It also fails to stem neurodevelopmental impairment by age 2, according to a recent study appearing in the New England Journal of Medicine.
The findings come from the Transfusion of Prematures (TOP) trial, which was conducted at 41 neonatal intensive care units across the United States. The investigators wanted to know whether higher hemoglobin thresholds for transfusing extremely low birth weight infants resulting in higher hemoglobin levels improves survival and rates of neurodevelopmental impairment at 22-26 months. These infants are at high risk for anemia because of their early stage of development, reduced ability to produce red blood cells, and need for blood sampling as part of their intensive medical care.
The trial of 1,824 infants weighing 1,000 grams or lower used an algorithm to assess when a transfusion was advised based on infant age and respiratory support. Of 845 infants assigned to a higher hemoglobin threshold, 423 died or survived with a neurodevelopmental impairment, compared to 422 of 847 infants assigned to a lower threshold. Infants assigned to both groups had similar rates of death and neurodevelopmental impairment.
At two years of age, the higher hemoglobin threshold increased the number of transfusions, but did not improve the chance of survival without neurodevelopmental impairment. By the time they were discharged from the hospital, 241 infants in the higher threshold group survived without severe complications compared to 262 infants in the lower threshold group.
Researchers will continue to assess the children in this study until five years of age to check for long-term differences in higher and lower threshold groups. The trial is partly-funded by NHLBI.