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Although platelet transfusions are currently administered on the basis of platelet counts or platelet mass, the evidence strongly suggests that factors other than the degree of thrombocytopenia determine the bleeding risk.
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Thus, larger studies are needed to better characterize the platelet function and the hemostatic profile of preterm infants, and their changes over time and in response to illness.
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It will be important to develop and validate tests that can be used in preterm infants and that
Platelet Transfusions in the Neonatal Intensive Care Unit
Section snippets
Key points
Platelet transfusion practices
Platelet transfusion remains the primary treatment modality for neonatal thrombocytopenia, but there is lack of agreement regarding the platelet count below which a newborn infant should be transfused. Nevertheless, it has been widely accepted that neonates should be transfused at higher platelet counts than older children and adults, and thus platelet transfusions are a frequent intervention in the NICU. In an earlier study of a single NICU in the United States with liberal transfusion
Primary hemostasis in the neonate
Multiple studies evaluating platelet activation and aggregation clearly demonstrated that neonatal platelets are hyporesponsive in vitro to most agonists (including adenosine diphosphate (ADP), epinephrine, collagen, thrombin, and thromboxane analogs), compared with adult platelets.12, 13 The underlying mechanisms responsible for the decreased platelet responses are different for each agonist. Specifically, the lack of response to epinephrine is explained by the presence of fewer α2-adrenergic
Relationship between severity of thrombocytopenia and bleeding risk
The combination of thrombocytopenia and platelet dysfunction in neonates has been invoked as a potential contributor to the high incidence of intraventricular hemorrhage (IVH) in preterm infants. In that regard, several studies have shown an association between thrombocytopenia and IVH, although this does not establish causality. Importantly, most neonates who experience IVH have normal or minimally decreased platelet counts at the time of their bleeds, highlighting the fact that the
Do platelet transfusions decrease the incidence of bleeding?
Platelet transfusions constitute the only readily available specific treatment for thrombocytopenia in neonates. Although platelet transfusions are frequently given to neonates with platelet counts below a certain arbitrary trigger, there is no good evidence to determine which neonate would benefit from a transfusion. In contrast to the multiple platelet transfusion trigger studies that have been performed in thrombocytopenic adults, the only platelet transfusion trigger trial performed in
Current recommendations
At this point, it is clear that additional well designed randomized controlled trials are needed to help identify safe and effective platelet transfusion thresholds for neonates. The PlaNeT-2 study is a large multicenter study conducted in several European countries that is comparing liberal versus restrictive prophylactic platelet transfusion strategies in thrombocytopenic preterm infants (50 vs 25 × 109/L, respectively).37 Approximately 350 infants have been enrolled to date, of a planned
Future directions
Although currently platelet transfusions are administered on the basis of platelet counts or platelet mass, the evidence strongly suggests that factors other than the degree of thrombocytopenia determine the bleeding risk. Thus, larger studies are needed to better characterize the platelet function and the hemostatic profile of preterm infants, and their changes over time and in response to illness. Along these lines, it will also be important to develop and validate tests that can be used in
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Disclosures: None.