Thrombopoietin following transfusion of platelets in preterm neonates

Thrombocytopenia is common in the neonatal intensive care unit. Transfusion of platelets is often required. The purpose of our study was to determine changes in thrombopoietin (Tpo) following transfusion of platelets in preterm neonates. Preterm neonates undergoing platelet transfusion were randomized to receive a transfusion volume of either 10 or 15 ml/kg. Blood was obtained for Tpo measurement pre-transfusion, one and 24 hours post-transfusion. Platelet Factor 4 (PF4) was also measured to quantify platelet activation. Statistical analysis was performed using repeated measures ANOVA, and Mann-Whitney U test as appropriate. Ten infants were enrolled in each group. Gestational age, birth weight, etiology of thrombocytopenia, and timing of transfusion did not differ between the 10 and 15 ml/kg groups. There were no differences between the groups in platelet count prior to and/or following transfusion. Both transfusion volumes were equally well tolerated. Tpo and PF4 did not differ between groups at any of the study time points. When both groups were analysed together, Tpo dropped 43% (95% confidence 37-49%, p = 0.01) 1-hour post compared to pre-transfusion. In conclusion the observed decrease in Tpo following platelet transfusion suggests that Tpo kinetics in neonates is similar to adults following transfusion. PF4 was not affected by transfusion. There was not an increase in platelet count following transfusion volume of 15 ml/kg compared to 10 ml/kg.