Transfusing neonates based on platelet count vs. platelet mass: A randomized feasibility-pilot study
Abstract The objective of this study was to obtain pilot data on which to judge the feasibility and sample size needed for a future comparative-effectiveness trial of platelet transfusions in the NICU. We conducted a limited-scope pilot trial in which neonates were randomized to receive platelet transfusions based on platelet mass vs. platelet count, using preset "transfusion-trigger" values. Analysis included parental consent rate, number of platelet transfusions given, bleeding episodes recorded, and mortality rate. Statistical analysis included ANOVA and Chi-square. A convenience sample of 30 were randomized; 15 per group. No differences were found between groups in gestational age, birth weight, race, gender or clinical diagnoses. The study consent rate was 52% (30/58). No differences were found in number of platelet transfusions received, bleeding episodes, or mortality. Lack of a trend in transfusion-reduction resulted in inability to estimate the number needed in a future comparative-effectiveness trial. Using platelet mass, rather than platelet count, for a NICU platelet transfusion trigger is feasible. However, any future comparative-effectiveness trial, testing the hypothesis that a platelet mass-based trigger reduces the transfusion rate will likely require a very large sample size.
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.